Apoptosis

Basic Mechanisms and Implications for Cardiovascular Disease

From the Cardiovascular Division, Beth Israel Deaconess Medical Center, Department of Medicine, Harvard Medical School, Boston, Mass.

Correspondence to Seigo Izumo, MD, Beth Israel Deaconess Medical Center, Room SL-201, 330 Brookline Ave, Boston, MA 02115. E-mail sizumo{at}bidmc.harvard.edu

Key Words: apoptosis • caspase • bcl-2 family • Fas • cardiovascular system

1. Introduction

Since Kerr et al¹ in 1972 coined the term "apoptosis" for a morphologically distinct mode of cell death, this concept of cell suicide has gained increasing interest in cytology and pathology. In terms of tissue kinetics, apoptosis may be considered a mechanism that counterbalances the effect of cell proliferation by mitotic division. In fact, deregulated apoptosis has been implicated as a fundamental pathogenetic mechanism in a variety of human diseases. Excessive apoptotic cell death may cause organ atrophy and organ failure, as suggested for neurodegenerative diseases and viral hepatitis. On the other hand, inefficient elimination of malignant, autoreactive, infected, or redundant cells may lead to the development of neoplasia, autoimmunity, viral persistence, and congenital malformations. Further interest in apoptosis has arisen from the recent elucidation of effector and regulatory mechanisms with the aid of molecular biology, genetics of lower organisms, and genetic modification of the mouse. However, only recently, compelling evidence has accumulated indicating that apoptotic cell death may also play a critical role in a variety of cardiovascular diseases, including myocardial infarction, heart failure, and atherosclerosis.

Apoptosis can be differentiated from other forms of cell death that occur in response to toxins, physical stimuli, and ischemia. Although not widely used, this form of cell death was termed "accidental cell death" in the pathology literature.² In contrast to apoptosis, accidental cell death does not involve suicide mechanisms and is not energy dependent. In the case of accidental cell death induced by ischemia, depletion of intracellular ATP stores, swelling, and disruption of the cell membrane, leading to liberation of cytoplasmic contents into the extracellular space, are prominent features (Figure 1). This specific form of accidental cell death is also referred to as "oncosis." The term "necrosis," often used to describe cell death other than apoptotic cell death, is imprecise, because it actually refers to irreversible cell and/or tissue alterations visible on microscopy irrespective of whether cell death is apoptotic or accidental.² For the scope of clarity and simplicity, we will refer to cell death characterized by caspase activation and caspase-mediated protein cleavage and internucleosomal DNA fragmentation as apoptotic (Figure 1). Other forms of cell death will be collectively summarized under the term "nonapoptotic cell death."

View larger version (21K): [in this window] [in a new window]   Figure 1. Classification of cell death based on the mechanisms believed to cause cell death. Nonapoptotic cell death associated with cell swelling is also referred to as oncosis. Fas indicates the death receptor Fas on the cell surface that can mediate ligand-induced cell apoptosis on stimulation.

Although some of the features of apoptosis have previously been summarized in several recent reviews,^3–8 research in apoptosis is progressing at a tremendous pace, and interesting new insights into the mechanisms of apoptosis have been gained since then. Because most of these findings have been made and published in the fields of immunology and oncology, it is the scope of this review both to provide an overview summarizing the important literature involving molecular mechanisms of apoptosis in general and to summarize current specific knowledge about apoptosis in cardiovascular disease. The morphological alterations associated with apoptosis will be addressed in the second section of this article. The third and fourth sections will review structure and function of caspases and mechanisms leading to their activation. On the basis of current evidence, mechanisms that depend on the activation of apoptosis-inducing cell surface receptors and on the mitochondrial release of proapoptotic factors will be addressed separately. Because apoptosis affects the basic function of a cell, namely cell viability, several mechanisms that regulate its initiation have evolved. These include mechanisms specific to apoptosis regulation (eg, bcl-2 family proteins) and signal transduction pathways involved in other cellular functions (eg, SAPKs). These are discussed in detail in sections 5 and 6, respectively. In addition, several reports suggest that apoptosis provides a safeguard against deregulated cell proliferation. Because this may be of pathophysiological significance in cardiovascular disease, this aspect was also included in the present review (section 7). Section 8 will give an overview of current evidence for apoptosis in cardiac development, heart failure, ischemic heart disease, and atherosclerosis. The final section (section 9) will summarize unanswered questions and the authors' perspective on future directions.

2. Morphology and Identification of the Apoptotic Cell

Morphology
Apoptosis is a distinct form of cell death that displays characteristic alterations in cell morphology and cell fate.² Chromatin condensation and margination that result in a "half-moon" or "horseshoe" appearance of the nucleus are typical features of apoptotic cell death.² Although morphological alterations of mitochondria may be subtle, mitochondrial function was reported to be irreversibly impaired early in apoptosis.^9,10 In addition, cytoskeletal alterations and membrane budding can be observed.^2,11 In later stages of apoptosis, nuclear fragmentation becomes evident (karyorrhexis), the cytoplasm condenses progressively, and one or more apoptotic bodies are formed from each dying cell. The cell remnants are taken up by phagocytic cells of the macrophage/monocyte lineage. Interestingly, apoptotic bodies may also be engulfed by cells not specialized in phagocytosis (eg, vascular smooth muscle cells).¹² Nuclear condensation, nuclear fragmentation, and sequestration of cell fragments have been documented in cardiomyocytes in situ.^13,14 Similar features have been observed in apoptotic smooth muscle cells of atherosclerotic lesions by light and electron microscopy, indicating that myocardial and vascular cells show at least some of the cytological features described in other cell types.^15–18

Attachment of apoptotic cell remnants to the phagocytosing cell appears to be mediated by various pathways. Interaction of phosphatidylserine on the cell surface of the apoptotic cell with phosphatidylserine receptors on the phagocytosing cells constitutes one major mechanism.^12,19 In most cell membranes, an asymmetry of phospholipids is maintained, with phosphatidylserine and phosphatidylethanolamine being confined to the inner leaflet of the cell membrane.²⁰ Possibly, through activation of a lipid scramblase or inhibition of the enzyme aminophospholipid translocase, this asymmetry of membrane composition is lost during apoptosis, leading to exposure of phosphatidylserine on the cell surface that can be recognized by specific receptors.²⁰ An alternative mechanism involves the vitronectin receptor, a protein of the integrin family present on fibroblasts and macrophages.^19,21,22 However, other mechanisms, such as lectin-mediated binding of sugar residues or CD14- and CD36-mediated binding, have been suggested.^23,23a In the central core of atherosclerotic lesions, lipid loading and apoptosis of macrophages may interfere with efficient removal of apoptotic cell remnants, leading to accumulation of cell debris in the central core.²⁴

Assays for Apoptosis
How can apoptosis be verified in tissue samples? The most convincing proof for apoptosis in tissue sections is the detection of apoptotic bodies containing nuclei with characteristic features of apoptosis. These are best visualized by electron microscopy. However, because apoptotic bodies are phagocytosed within hours after cell death, apoptotic cell remnants may be difficult to verify whenever apoptosis affects only a limited number of cells or occurs only transiently. Nuclear staining with the fluorescent dye bisbenzimide (Hoechst 22358) allows for the visualization of nuclear condensation and fragmentation in both cell culture and tissue sections.

The most commonly used techniques to detect apoptosis are based on the fact that during apoptosis the genomic DNA is cleaved within internucleosomal DNA segments by an endonuclease selectively activated during apoptosis.^25,26 Internucleosomal DNA fragmentation appears to be preceded by the formation of larger DNA fragments with lengths of 50 and 300 kb.^27,28 In some cells, degradation to small internucleosomal fragments may not take place at all.²⁸ Separation of cellular DNA on agarose gels shows a characteristic ladderlike pattern of fragments with multiples of 200 bp in length. The disadvantage of this technique is that it is not possible to assign the apoptotic process to a specific cell type whenever tissue samples containing different cell populations are analyzed.

Therefore, other techniques that allow for histochemical analysis have been developed. In the TUNEL (TdT-mediated dUTP nick end-labeling) technique, dUMP is attached to the 3' end of genomic DNA by TdT (terminal deoxynucleotidyltransferase). Positive cells are visualized by fluorescent dyes conjugated to dUTP.²⁹ An alternative technique, in situ end-labeling (ISEL), uses the Klenow fragment of Escherichia coli DNA polymerase I that recognizes only 3' recessed ends, whereas TdT processes any type of free 3' ends.³⁰ Comparative analysis suggests a higher sensitivity for the TUNEL technique in the detection of apoptosis.³¹ However, a cautious note needs to be added, because exposure of 3' DNA ends is not a unique feature of apoptosis and may occur during DNA repair and nonspecific DNA damage, potentially limiting the specificity of this technique.^32,33 Sensitivity for the detection of DNA fragmentation in individual cultured cells may be increased by the "comet assay."^34,35 In this assay, cells are lysed in agarose and subjected to gel electrophoresis. Fragmented DNA migrates out of the nucleus and forms a characteristic comet tail. Although this technique displays a high sensitivity for DNA breaks, it does not provide definite proof of the internucleosomal DNA cleavage characteristic of apoptosis.³⁶

Because the enzymatic fragmentation of the DNA is a late event in apoptosis, there is an ongoing search for markers that allow for the detection of cells that are still in the early phases of apoptosis. Current evidence suggests that the binding of annexin V to phosphatidylserine exposed on the outer leaflet of the cell membrane may constitute an advance in this direction.²³ In addition, specific cleavage of cellular target proteins, such as poly(ADP)-ribosylating protein, is considered to be a hallmark of apoptosis.^6,8,36 Detection of protein fragments by Western blotting has been used to verify apoptotic cell death in cell culture models of apoptosis.

3. Caspases as the Effector Machinery of Apoptosis

A key phenomenon of apoptotic cell death is the activation of a unique class of aspartate-specific proteases. Until now, at least 10 members have been identified in this subclass of proteases (Table 1).⁶ In order to simplify the confusing terminology of the known aspartate-specific proteases, a new nomenclature has been adopted, classifying all aspartate-specific proteases under the term caspases.³⁷ Crystal structure analysis of the prototypical caspase ICE (caspase-1) revealed that the serine residue common to many other proteases is replaced by a cysteine residue within a highly conserved pentameric sequence in the catalytic center.^38,39 All caspases are composed of a prodomain and an enzymatic region (Figure 2). Heterogeneity among the proteases exists regarding the structure of the prodomain, suggesting that this region may define important functional differences between caspases. Caspases-1, -2, -4, -5, -8, -9, and -10, like their Caenorhabditis elegans homologue ced-3, contain a long prodomain of 15 to 25 kDa compared with <5 kDa in caspases-3, -6, and -7 (Figure 2 and Table 1). For activation, the caspase proform has to be cleaved into a large subunit and a small subunit within the enzymatic domain that finally reassociate to form a complex comprising 2 small and 2 large subunits. The prodomain is not necessary for the proteolytic activity once the caspase is activated. Interestingly, all activating cleavages occur behind an aspartate residue. Because this cleavage site is a unique characteristic of caspases (with the serine protease granzyme B being the only exception), activation can occur only through autoactivation or cleavage by another caspase or granzyme B.

View larger version (15K): [in this window] [in a new window]   Figure 2. Structural characteristics of caspase-3 and -8. The black segment within the large catalytic subunit indicates the catalytic center of the caspase. The shaded subregions within the prodomain of caspase-8 represent the death effector domains required for the recruitment of caspase-8 to the activated death receptor complex. Asp indicates the cleavage sites for activation of the caspases. Pro indicates the prodomain; p12/p17 and p11/p18, the enzymatic subunits of caspase-3 and -8, respectively.

In contrast to the nematode C elegans, where only one caspase, ced-3, has been identified, we face the dilemma of defining the specific functional role of several different members of this protease family in the mammalian system.^6,40 Do they function in a sequential activation cascade as in the coagulation system, or do they act in parallel, forming at least partially redundant pathways? Surprisingly, phenotypic analysis of mice with a deficiency of the prototypical mammalian ced-3 homologue ICE (caspase-1) exhibited normal intrauterine and postnatal development.⁴¹ Although caspase-1^-/- thymocytes showed impaired Fas-induced apoptosis in vitro, a phenotype similar to mice deficient in the apoptosis-mediating receptor Fas or its ligand with lymphoid hyperplasia and autoimmunity could not be observed.⁴¹ In addition, sensitivity to radiation and glucocorticoids was not reduced, suggesting that caspase-1 does not play a major role within the apoptotic machinery or that it can efficiently be replaced by other caspases. In contrast, mice deficient in caspase-3 exhibited a striking phenotype of multiple neuronal hyperplasia in the brain consistent with inefficient cell elimination during fetal development.⁴² Changes in brain histology became obvious from gestational day 12 on and resulted in markedly reduced prenatal and postnatal viability. Intriguingly, no abnormalities were found in other tissues, including the heart and the immune system, where apoptosis is known to play a major role in cell maturation. A possible explanation is that in those tissues redundant caspase activities are expressed that compensate for the loss of caspase-3 function.

Apart from differences in prodomain length, caspases can be grouped according to the sequence requirement surrounding the target aspartate residue. Caspases-6, -8, and -9 preferentially cleave protein substrates at (valine/leucine)-glutamate-(threonine/histidine)-aspartate (V/L-E-T/H-D), whereas caspases-3 and -7 show a high selectivity for a peptide motif consisting of aspartate-glutamate-valine-aspartate (DEVD).⁴³ The optimal target sequence for caspase-1 and the related caspases-4 and -5 is believed to be tyrosine-valine-alanine-aspartate (YVAD) or the tetrapeptide (tryptophan/leucine)-glutamate-histidine-aspartate (W/L-EHD).⁴³

Enari et al⁴⁴ showed that in apoptosis induced by stimulation of the death receptor Fas, caspases that are competitively inhibited by a YVAD oligopeptide are upstream from caspases that are inhibited by DEVD peptides (eg, caspases-3 and -7), suggesting the sequential activation of caspase subgroups. Recruitment of caspases-2 and -8 through their prodomains to the Fas receptor complex supports the notion that these proteases are activated early through a receptor-dependent mechanism.^45–49 This may also be true for caspase-10, whose prodomain shows a high homology to the prodomain of caspase-8.⁵⁰

Target proteins for caspases comprise a plethora of different proteins, including nuclear proteins, proteins involved in signal transduction, and cytoskeletal targets (Table 2).^6,8,51–53 Most of these protein substrates appear to be cleaved by caspases-3 and -7. However, lamin is selectively cleaved by caspase-6.^54,55 Although many of the target proteins defined to date have a nuclear localization, apoptotic cell death does not depend on the presence of a cell nucleus, as the characteristic cytoplasmic features of apoptosis can be observed in anucleate cytoplasts.⁵⁶ Therefore, proteolytic cleavage of nuclear proteins may be important in eliciting the nuclear features of apoptosis, like chromatin margination induced by lamin B cleavage, but does not constitute a critical event for the apoptotic death of the entire cell.^57,58 Interestingly, internucleosomal DNA fragmentation requires the prior cleavage of a cytoplasmic inhibitor of the apoptosis-specific endonuclease (inhibitor of caspase-activated DNAse, DNA fragmentation factor).^26,53,57 Only after cleavage of the inhibitor can the endonuclease translocate to the nucleus and degrade genomic DNA.^26,53 For most of the downstream targets, the overall contribution to the final cell fate remains to be determined.

In summary, caspases can be grouped into an upstream and a downstream subgroup. Upstream caspases are characterized by long prodomains that appear to contain essential regulatory regions. Most of the activity that finally leads to the lethal proteolytic breakdown of cellular target proteins is exerted by downstream caspases sensitive to DEVD oligopeptides (caspase-3 and caspase-7).

4. Mechanisms of Caspase Activation

Once downstream caspases that execute the lethal cuts to vital cellular components are activated, cell death appears to be inevitable. Therefore, understanding the mechanisms that initiate proteolytic activation of caspases is a crucial step in defining targets that allow for the modulation of apoptotic cell death. Recent data suggest that activation of caspases may take place either within death receptor complexes of the cytoplasmic membrane or by a mitochondrion-dependent mechanism within the cytosol (Figure 3).

View larger version (34K): [in this window] [in a new window]   Figure 3. Schematic diagram of the apoptotic death pathway. Caspases are activated by a receptor- or mitochondrion-dependent mechanism. Subsequent cleavage of multiple cellular target proteins finally results in apoptotic cell death. Antiapoptotic mechanisms are indicated in white boxes. FLIP and IAP indicate FLICE-like inhibitory protein and inhibitor of apoptosis protein, respectively.

Death Receptor Pathway
One of the best characterized pathways for the initiation of apoptosis involves the binding of extracellular death signal proteins (TNF-, FasL, TRAIL, and Apo-3L) to their cognate cell surface receptors.^59–61,61a At present, the cDNA sequences of 5 death receptors are known (Table 3).^62–67 The death receptors contain a distinct cytoplasmic domain comprising 80 amino acid residues that is critical for their proapoptotic function.^68,69 Given its importance in the transmission of proapoptotic signals, this domain was designated "death domain."

The mRNA for the prototypical death receptor Fas was shown to be detectable in several different organs, including the heart, and in atherosclerotic lesions.^18,70–72 Mice deficient in Fas and mice carrying spontaneous mutations of either FasL (gld mice) or Fas (lpr mice) exhibit a phenotype of lymphoproliferative and autoimmune disease.^73–75 In patients with Canale-Smith syndrome, a syndrome caused by a mutation of the Fas gene, similar characteristics of lymphoproliferation, autoimmune hemolytic disease, thrombocytopenia, and an additional propensity for neoplasia were described.⁷⁶

Signal transduction through the death receptor involves a unique set of proteins that are not part of other signal transduction pathways (Figure 4). After binding of their cognate ligands, the death receptors form a homotrimeric complex and, by virtue of death domain-mediated protein-protein interactions, recruit intracellular adaptor proteins to the cell membrane. In the case of TNF- receptor 1 (TNFR1) and death receptor 3 (DR3), this is TNFR-associated death domain protein (TRADD), whereas Fas and DR4 interact with Fas-associated death domain protein (FADD).^{46,64–66,77,78} FADD and TRADD appear not to interact with DR5, suggesting that additional, so far unknown, proteins may be involved.⁶⁷ Signaling induced by activation of TNFR1 or DR3 diverges at the level of TRADD.⁷⁸ On the one hand, nuclear translocation of the transcription factor nuclear factor B (NFB) and activation of c-Jun N-terminal kinase (JNK) are initiated.^64,79,80 On the other hand, TNF- signaling is linked to the Fas signaling pathway through interaction of TRADD with FADD. Surprisingly, FADD knockout mice exhibit a phenotype of ventricular thinning and poorly developed trabeculation of the heart.^80a An additional death domain–containing protein, receptor-interaction protein (RIP), was also shown to interact with the cytoplasmic domain of TNFR1.^81,82

View larger version (18K): [in this window] [in a new window]   Figure 4. Signaling mechanisms implicated in the transduction of proapoptotic and antiapoptotic signals after stimulation of tumor necrosis factor receptor 1. Protein domains essential for protein-protein interactions and signal transduction are highlighted. CRADD indicates caspase and RIP adaptor with death domain; FADD, Fas-associated death domain protein; FasL, Fas ligand; MORT, mediator of receptor-induced toxicity; NFB, nuclear factor B; RAIDD, RIP-associated ICH-1/Ced-3-homologous death domain protein; RIP, receptor-interaction protein; TNFR, tumor necrosing factor receptor; TRADD, TNFR-associated death domain protein; and TRAIL, TNF-related apoptosis-inducing ligand.

Induction of apoptosis by FasL and TNF- critically depends on caspase activation.⁸³ FADD was shown to directly interact with caspase-8.^45,46,50 Similarly, caspase-2 can be recruited to RIP through an adaptor protein called RIP-associated ICH-1/Ced-3-homologous death domain protein (RAIDD).⁴⁷ Interaction of FADD and RAIDD with the caspases requires the so-called death effector domain (DED) that shows homology to the prodomain of the targeted protease.⁸⁴

Mitochondrial Pathway
Recent reports suggest an important role of the mitochondrion in the induction of apoptotic cell death. Using a cell-free assay, Liu et al⁸⁵ defined three proteins in addition to dATP or ATP that are required for caspase-3 activation (Figure 5).⁸⁵ Surprisingly, one of the proteins was identified as the mature heme-containing form of cytochrome c that is located in the mitochondrial intermembranous space under physiological conditions.^85–88 The release of cytochrome c into the cytoplasm appears to be a crucial step for this mechanism of caspase activation. As a potential release mechanism, mechanical rupture of the outer mitochondrial membrane secondary to mitochondrial swelling was suggested.⁸⁹ However, it has to be kept in mind that in most apoptotic cells, mitochondria are not obviously swollen.²

View larger version (22K): [in this window] [in a new window]   Figure 5. Schematic diagram showing the mechanism of cytochrome c–dependent caspase activation.

Interestingly, the second protein, termed apaf-1, is considered to be a mammalian homologue of the proapoptotic factor ced-4 of C elegans.⁹⁰ The third protein involved, apaf-3, was recently shown to be identical to caspase-9.⁹¹ Interaction between caspase-9 and apaf-1 is mediated through homologous regions in the prodomain of the caspase and the amino terminus of apaf-1 and depends on the presence of cytochrome c and dATP (>1 µmol/L) or ATP (>1 mmol/L). Nonhydrolyzable ATP analogues are nonfunctional, indicating that cytochrome c–mediated caspase activation may be an energy-dependent process.⁹¹

In addition to the release of cytochrome c, an alternative mechanism involving the release of another mitochondrial protein, termed apoptosis-inducing factor (AIF), has been proposed.⁹² Unlike cytochrome c, AIF proved to have a proteolytic activity that could be blocked by a broad-spectrum caspase inhibitor but not by inhibitors specific for caspase-1 and -7.⁹³ The release of AIF was shown to depend on the opening of the mitochondrial permeability transition pore that results in the breakdown of the proton and electrical gradients over the inner mitochondrial membrane.⁹⁴ In contrast, cytochrome c release was independent of the formation of the permeability transition pore and even occurred when the gradients over the inner mitochondrial membranes were maintained.^86,87

5. Regulatory Proteins

Given the fact that the effector machinery for apoptotic cell death is already in place in all nucleated metazoan "cell types," it is not surprising that mechanisms have evolved that allow for a tight regulation of apoptosis.⁹⁵ Recent evidence indicates that regulatory mechanisms affect different levels in the sequence of apoptotic events. In the mammalian cell system, inhibitory proteins have been characterized that prevent the activation of caspases as well as inhibit the proteolytic activity of caspases (Figure 3). Interestingly, most of the strategies for the inhibition of apoptosis are copied by viruses that are capable of maintaining a persistent infection of the host cell.

Bcl-2 Protein Family
Genetic analysis in the nematode C elegans defined a genetic locus, ced-9, whose loss-of-function mutation caused apoptosis, thus defining a negative regulator of apoptosis.⁹⁶ The mammalian homologue bcl-2 was initially discovered by virtue of its reciprocal translocation (t14;18) to the immunoglobulin heavy chain locus in follicular B-cell lymphomas and in acute lymphoblastic leukemia, promoting survival of neoplastic cells.⁹⁷ Expression of human bcl-2 in C elegans can functionally substitute for the deficiency of ced-9, suggesting a high degree of functional conservation during evolution.⁹⁸ As in the case of caspases, mammalian cells rely on a whole family of proteins structurally related to ced-9 (Figure 6). In overexpression experiments, members of the mammalian bcl-2 protein family were shown to mediate both proapoptotic and antiapoptotic regulation.^99–110

View larger version (19K): [in this window] [in a new window]   Figure 6. Structural features of antiapoptotic and proapoptotic members of the bcl-2 protein family. BH and TM indicate bcl-2 homology domain and transmembrane domain, respectively.

Functional importance of bcl-2–related proteins is suggested by the phenotypic alterations observed in mice deficient in the antiapoptotic regulators bcl-2 and bcl-x. Bcl-2 knockout mice are characterized by massive apoptotic cell death of lymphocytes in lymphoid tissues as well as by polycystic kidneys, hypopigmented hair, and intestinal abnormalities.^111–114 Interestingly, despite widespread bcl-2 expression in the fetus, intrauterine development was not impaired, and progressive reduction in body weight and increased mortality became obvious only during the postnatal period. Isolated bcl-2^-/- thymocytes had a markedly increased sensitivity to dexamethasone- and irradiation-induced apoptosis.¹¹³ In contrast to bcl-2 knockout mice, mice deficient in the antiapoptotic regulator bcl-x died in utero at approximately day 13.¹¹⁵ Histological analysis showed impaired hematopoiesis and deregulated brain development. The phenotypic differences in the knockout studies suggest that the genes for regulatory proteins may not necessarily function interchangeably because of either a tissue-specific expression pattern or true functional differences. The targeted disruption of the proapoptotic bax gene resulted in a phenotype characterized by lymphoid hyperplasia, hyperplasia of ovarian granulosa cells, and male infertility due to impaired spermatogenesis in the testes.¹¹⁶

Interestingly, abnormalities in the cardiovascular system have not been observed in any of these knockout studies. This, however, does not preclude the possibility that proteins of the bcl-2 protein family are of functional importance in the cardiovascular system, as the loss of one antiapoptotic protein may be compensated for by other members of the same protein family or by alternative antiapoptotic mechanisms. Expression of bcl-2, bcl-x_L, and bax has been documented in cardiomyocytes and in atherosclerotic lesions by immunohistochemistry.^{71,72,117–119} In addition, overexpression of bcl-2 in cardiomyocytes and vascular smooth muscle cells in vitro can prevent apoptotic cell death induced by p53, indicating that all other proteins required for bcl-2 to exert its antiapoptotic function are functional in these cells.^120,121

Structurally, proteins of the bcl-2 family contain different combinations of 4 conserved domains termed BH1 (bcl-2 homology), BH2, BH3, and BH4 (Figure 6).^103,122,123 In most bcl-2–related proteins, localization to the outer mitochondrial and nuclear membranes as well as to the endoplasmic reticulum is mediated by a carboxy-terminal transmembrane domain.^124,125 All antiapoptotic bcl-2–related proteins contain BH1, BH2, BH4, and transmembrane domains. In contrast, the minimal structural requirement for proapoptotic members of this protein family is an intact BH3 domain.^108,109 Surprisingly, the 3-dimensional structure of bcl-x_L showed a close similarity to bacterial proteins that form transmembrane channels, allowing for the translocation of bacterial peptide toxins.¹²⁶ In fact, integration of bcl-x_L into artificial membranes created a large nonselective transmembrane ion conductance.¹²⁷

Four principal mechanisms for the bcl-2–mediated antiapoptotic effect have been proposed. These include (1) a direct antioxidant effect, (2) inhibition of the release of proapoptotic mitochondrial proteins, (3) sequestration and/or modulation of the proapoptotic ced-4 protein and its mammalian homologue, and (4) inhibition of a direct cytotoxic effect of the proapoptotic regulators bax and bak (Figure 7). The generation of reactive oxygen species was initially suggested to be a common final pathway of apoptosis that could be abrogated by the antioxidant activity of bcl-2.¹²⁸ However, later observations indicating that bcl-2 was protective against staurosporine-induced apoptosis even under hypoxic conditions, where the generation of reactive oxygen species is markedly reduced, called this mechanism as the general function of bcl-2 into question.¹²⁹

View larger version (25K): [in this window] [in a new window]   Figure 7. Mechanisms suggested to mediate the antiapoptotic effect of bcl-2. AIF indicates apoptosis-inducing factor.

Increasing evidence suggests that the function of bcl-2 is strongly related to the regulation of protein translocation from the mitochondrial intermembrane space into the cytosolic compartment. Overexpression of bcl-2 effectively blocked the release of cytochrome c from mitochondria into the cytosol.^86,87 This finding is in concordance with previous data indicating that activation of caspase-3, -6, and -7 is downstream from bcl-2.^54,130,131 Likewise, bcl-2 blocked the release of AIF, suggesting that bcl-2 and its antiapoptotic congeners may function as a "guardian" against mitochondrial initiation of caspase activation.⁹³

An intriguing finding is the observation that ced-9, the C elegans homologue of mammalian bcl-2, directly interacts with ced-4, a proapoptotic protein in C elegans that is involved in the activation of the caspase ced-3.^132,133 Actually, ced-4 is essential for ced-9 to execute its antiapoptotic function.¹³⁴ As outlined above, the mammalian ced-4 homologue apaf-1 forms a complex with cytochrome c, (d)ATP, and caspase-9 to activate caspase-3. Given the fact that human bcl-x_L can interact with ced-4, it seems plausible that antiapoptotic bcl-2 family proteins directly interfere with cytochrome c–dependent caspase activation.^91,132 In addition, direct competition of bax with ced-4 to bind to bcl-x_L was proposed to mediate the proapoptotic effect of bax.¹³²

However, overexpression of bax and bak in the yeast Saccharomyces cerevisiae, which does not contain endogenous bcl-2 family proteins, was shown to induce cell death, indicating that bax and bak have a direct cytotoxic effect independent from the inactivation of antiapoptotic bcl-2 proteins.¹³⁵ Cell death could be blocked by concomitant expression of antiapoptotic bcl-2 family proteins. Part of the antiapoptotic effect of bcl-2 may therefore be attributed to the inhibition of a direct cytotoxic effect of bax and bak.¹³⁵

Inhibitor of Apoptosis Proteins
The prototypical form for this family of proteins was initially isolated from baculovirus, a virus infecting insect cells.¹³⁶ In the mammalian system, five homologues have been identified; they are termed X-linked IAP, neuronal IAP, c-IAP1, c-IAP2, and survivin.^137–139 c-IAP1 and c-IAP2 were shown to bind to TNF- receptor–associated factor 1 and 2 (TRAF1 and TRAF2) and thus can be recruited to the activated TNFR complex.¹⁴⁰ c-IAP2 was suggested to be involved in TNF--mediated activation of the NFB pathway that confers protection against apoptosis.¹⁴¹ Direct inhibition of caspase activity was recently shown to be an alternative antiapoptotic mechanism of this class of proteins. X-linked IAP, c-IAP1, and c-IAP2 were shown to interact with and inhibit downstream caspases (caspase-3 and -7), thereby inhibiting apoptosis initiated either by receptor-mediated or by cytochrome c–dependent mechanisms.^142,143

Inhibition of Receptor-Mediated Caspase Activation
As outlined above, initiation of apoptosis by death receptor ligands requires the recruitment of proteins to the activated death receptors mediated through death domains and DEDs. Database searches led to the isolation of viral proteins that contain DEDs and promote cell survival when overexpressed in cells.^144,145 Mammalian homologues of the viral inhibitors termed FLIP, I-FLICE, CASH, and FLAME-1 show a high degree of homology to caspase-8 and -10, although the protease domain appears to be nonfunctional.^146–149 A similar nonfunctional homologue of caspases-2 and -8 termed apoptosis repressor with caspase recruitment domain (ARC) appears to be selectively expressed in skeletal and cardiac muscle.^149a Most likely, this class of proteins competitively inhibits receptor-induced activation of upstream caspases. In addition, a TRAIL receptor lacking the intracytoplasmic region essential for transduction of the death signal was isolated.¹⁵⁰ Because this receptor is attached to the cell membrane through a phosphatidylinositol anchor, it can be released enzymatically.¹⁵⁰ The death receptors Fas and TNFR1 were also shown to exist in soluble forms.^151,152 At present, it is not known whether these soluble death receptors exert a physiological role as scavengers for death receptor ligands.

6. Signal Transduction

Only recently have efforts been made to disentangle the intricate relationships between signal transduction and apoptosis (Figure 8). Analysis is complicated by the fact that receptor agonists may activate several signal transduction mechanisms with opposing effects on apoptosis regulation.

View larger version (28K): [in this window] [in a new window]   Figure 8. Signal transduction pathways implicated in the regulation of cell survival and apoptosis. ASK indicates apoptosis signal-regulating kinase; CAPK, ceramide-activated protein kinase; CAPP, ceramide-activated protein phosphatase; ERK, extracellular signal–regulated kinase; IB, inhibitor of nuclear factor B; JNK, c-Jun N-terminal kinase; MEK, MAPK/ERK kinase; NFB, nuclear factor B; NGF, nerve growth factor; PI-3K, phosphatidylinositol-3 kinase; PKB, protein kinase B; SEK, SAPK/ERK kinase; TNF-, tumor necrosing factor-; TRAF2, TNF- receptor–associated factor 2.

Stimulation of TNFR1 and DR3 activates the nuclear transcription factor NFB, a heterodimeric complex composed of a Rel subunit (RelA, RelB, or c-Rel) and either the p52 or p50 subunit.¹⁵³ IB sequesters and thus inactivates NFB in the cytoplasm. Degradation of the inhibitory subunit IB by a ubiquitin-dependent pathway allows for the nuclear translocation of NFB and transcriptional transactivation of target genes. Using an IB mutant that resists inactivation, cell viability was markedly reduced after treatment with TNF-, daunorubicin, or irradiation.^154–156 Furthermore, mouse fibroblasts deficient in the RelA subunit of NFB became sensitive to TNF-, whereas the parental cell line was resistant to the proapoptotic effect of TNF-, indicating that the apoptotic activity of TNF- depends on whether NFB signaling is inactivated in addition to the recruitment of FADD and caspase-8.¹⁵⁷ In fact, RelA knockout mice die in utero because of liver atrophy due to massive apoptosis of hepatocytes.¹⁵⁸

Survival factors like interleukin-3, nerve growth factor (NGF), insulin-like growth factor-1 (IGF-1), or platelet-derived growth factor protect cells from undergoing apoptotic cell death. The cognate receptors belong to the family of protein tyrosine kinase receptors that are implicated in the activation of phosphatidylinositol-3 kinase (PI-3 kinase). Rescue of PC12 pheochromocytoma cells with NGF or IGF-1 depends on the activation of PI-3 kinase.^159–161 Downstream from PI-3 kinase, Akt (also known as protein kinase B [PKB]) was found to be critical for the prevention of apoptotic cell death.^161–163

The discovery that bad, a proapoptotic bcl-2 family protein, can be phosphorylated by PKB/Akt provided the first direct link between a growth factor signal transduction pathway and apoptosis regulatory proteins.¹⁶⁴ Phosphorylated bad was shown to bind less efficiently to membrane-associated bcl-x_L.¹⁶⁵ Because bad lacks a carboxy-terminal membrane anchor, reduced affinity for membrane-associated bcl-x_L results in the translocation of bad from the intracellular membrane fraction to the cytosol, where it is sequestered in a complex with 14-3-3 proteins. In accordance with this, substitution of two specific serine phosphorylation sites increases the proapoptotic activity of bad.¹⁶⁵

In mammalian cells, four parallel kinase cascades have been described that finally lead to the activation of members of the mitogen-activated protein kinase (MAPK) family, such as the ERKs (p42 and p44), JNK (alternatively called SAPK), and p38 protein kinase.^166,167 In several cell types, a proapoptotic role for the kinase cascade MEKK1-SEK-JNK was shown.^168–172 A similar role has been suggested for the p38 kinase cascade, although available evidence is limited.^168,173 Activation of the JNK pathway is implicated in the initiation of apoptosis by different stress stimuli. In a recent report, even Fas-induced apoptosis was shown to be partly dependent on JNK activation, which was mediated by a novel signal transduction molecule termed Daxx.¹⁷⁴ Likewise, apoptosis signal-regulating kinase 1 (ASK1), an upstream activator of the JNK kinase (SEK), was shown to promote TNF-–induced apoptosis.¹⁷⁵ However, in SEK knockout mice, apoptosis triggered by several stress stimuli was not impaired in thymocytes compared with control cells.¹⁷⁶ Further study is required to elucidate the proapoptotic pathways that involve JNK and p38.

Increasing evidence suggests that activation of the Ras–Raf-1–MEK–ERK pathway is protective against apoptotic cell death. Raf-1 is targeted by bcl-2 to the outer mitochondrial membrane, where it phosphorylates bad.¹⁷⁷ However, the functional significance of this is not clear, since phosphorylation does not involve the serine residues essential for the cytoplasmic sequestration of bad.¹⁶⁵ Constitutively active MEK rescues neuronal cells from apoptotic cell death induced by growth factor withdrawal.^160,168 Cardiomyocytes were shown to be protected from apoptotic cell death after serum deprivation by cardiotrophin-1.¹⁷⁸ Interestingly, the protective effect of cardiotrophin-1 could be blocked by an inhibitor of MEK. Furthermore, blockade of ERK activation augmented apoptosis induced by oxidant stress in neonatal rat ventricular cardiomyocytes, suggesting that the ERK pathway can mediate antiapoptotic signaling in neonatal cardiomyocytes.¹⁷⁹ The antiapoptotic effect of bcl-2 depends on serine phosphorylation between the BH3 and BH4 domains.¹⁸⁰ Signaling through the Raf-1–MEK–ERK pathway has been implicated in the phosphorylation of bcl-2, providing a potential link between ERK activation and cell survival.^180,181

An additional signaling mechanism related to the regulation of apoptosis involves the formation of ceramide from sphingomyelin.^169,182 Interestingly, generation of ceramide appears to be an early event in some forms of stress-induced apoptosis, being detectable within only 10 minutes. Cells from patients with Niemann-Pick disease (hereditary deficiency of acid sphingomyelinase) and from knockout mice deficient in acid sphingomyelinase exhibited a markedly decreased sensitivity to radiation-induced apoptosis.¹⁸³ Although several downstream targets in ceramide signaling have been recognized, including protein kinase C (PKC), ceramide-activated protein phosphatase (CAPP), and ceramide-activated protein kinase (CAPK), the mechanisms that link ceramide signaling pathways to the activation of caspases are still incompletely understood.¹⁸²

7. p53 and Apoptosis

Several reports have established a relationship between DNA damage, cell cycle control, and apoptosis. Inducers of apoptosis that cause DNA damage (eg, UV- or -irradiation and chemotherapeutic drugs) proved to depend on functional p53.^184,185 In addition, when cells are induced to proliferate by deregulated expression of the adenoviral oncoprotein E1A or the oncogene c-myc, they undergo apoptosis, unless they are rescued by bcl-2 or its adenoviral homologue E1B.^186–188 In serum-starved fibroblasts, apoptosis was clearly related to crossing the G₁/S cell cycle checkpoint, as only those cells that showed evidence for DNA synthesis became apoptotic.¹⁸⁹ Interestingly, cell cycle reentry, DNA synthesis, and apoptotic cell death have also been observed in neonatal and cardiac cardiomyocytes overexpressing the positive cell cycle regulators E2F-1 or adenoviral E1A.^190–192 Apoptosis induced by forced cell cycle reentry was reported to depend on p53 in fibroblasts and kidney cells.^193–195 However, despite the capacity of neonatal cardiomyocytes to undergo apoptosis in response to p53 overexpression, myocyte apoptosis induced by forced entry into the S phase of the cell cycle was shown to occur in p53-deficient mice.^120,192,196

The proapoptotic effect of p53 has been linked to the p53-induced expression of Fas, bax, and IGF binding protein-3.^197–200 In an extensive analysis of the gene expression pattern during p53-mediated apoptosis of a colon cancer cell line, 7 of 14 genes that were induced at least 10-fold by p53 were involved in cellular redox reactions.²⁰¹ Since antioxidants reduced the extent of p53-induced apoptosis, oxidative stress seems to constitute an important intermediary step in p53-mediated apoptosis.²⁰¹

8. Evidence for Apoptosis in the Cardiovascular System

Although apoptosis has long been recognized as a principal mechanism for the elimination of redundant, autoreactive, or neoplastic cells, only recently a critical role of apoptosis was suggested in several cardiovascular diseases (Table 4).

Apoptosis in Cardiac Development
During cardiac development, programmed cell death was suggested to be of importance in the formation of septal, valvular, and vascular structures, implicating the potential importance of either excessive or inappropriate apoptosis in congenital heart disease.²⁰² However, so far, direct evidence for an apoptotic cell death by TUNEL staining has been provided only for mesenchymal cells in the bulbus cordis of the rat heart at 14 and 16 days of gestation.²⁰³ Excessive apoptosis of the cardiac conduction system was suggested to be a possible mechanism in the pathogenesis of heart block.^204,205 On the other hand, incomplete apoptotic cell deletion has been postulated to cause the persistence of accessory atrioventricular conduction pathways, such as in Wolff-Parkinson-White syndrome.²⁰⁴

Apoptosis and Heart Failure
The factors that lead to the development and progression of heart failure are still not fully understood. Besides myocyte hypertrophy, myocyte dysfunction due to altered calcium homeostasis, impaired myofilament Ca²⁺ sensitivity, fiber slippage, and myocardial fibrosis, progressive loss of cardiomyocytes is considered to play a major contributory role.^206–208 In canine models of pacing-induced heart failure and heart failure due to chronic ischemic injury, loss of cardiomyocytes due to apoptosis was detectable by TUNEL staining, whereas in control myocardium only rare cardiomyocytes stained positive.^13,209 Narula et al²¹⁰ reported that in myocardial specimens from patients undergoing cardiac transplantation, apoptosis detected by TUNEL staining was consistently observed in idiopathic dilated cardiomyopathy but not in ischemic cardiomyopathy. However, in a more recent study, this difference with regard to the etiology of heart failure could not be confirmed.¹¹⁸ Furthermore, in a series of patients with arrhythmogenic right ventricular dysplasia (a myocardial disease characterized by fibrofatty replacement of right ventricular cardiomyocytes and a high incidence of ventricular arrhythmia and sudden cardiac death), histological evidence for myocyte loss due to apoptotic cell death has been shown in 6 of 8 patients.²¹¹ Notably, an infiltration by inflammatory cells was absent in the tissue sections of patients with heart failure, indicating that cell-mediated cytotoxicity by immune cells appears not to play a major role under these conditions. In heart failure, the apoptotic index, ie, the number of TUNEL-positive nuclei per 100 nuclei, was reported to be as high as 35.5% in the initial study.²¹⁰ Given the fact that the TUNEL-positive state after apoptotic cell death may last <24 hours, this high degree of myocyte loss would lead to rapid organ destruction. Much lower values for the apoptotic index (0.2% to 0.4%) that are still >100-fold above control values may therefore more reliably reflect the overall extent of ongoing myocyte apoptosis in heart failure.^13,118

Potential mechanisms for the induction of apoptotic cell death at the cellular level may involve mechanical factors or elevated levels of neurohumoral factors. In an experimental model of isometric stretch of papillary muscle, apoptosis of cardiomyocytes could be detected in 0.64% of cardiomyocytes by TUNEL staining, indicating that volume overload and elevated end-diastolic left ventricular pressure may constitute an initiating event for myocyte apoptosis.²¹² After aortic banding in rats, apoptosis of myocytes could be verified in tissue sections, further emphasizing the potential role of hemodynamic factors. Peak cell loss was observed 4 days after aortic banding.²¹³

Kajstura et al²¹⁴ observed an increased percentage of apoptotic cells in isolated adult cardiomyocytes after treatment with angiotensin II (0.9% apoptotic cells in angiotensin II–treated cells versus 0.2% in control cells). This effect was mediated by AT₁ angiotensin II receptors, raising the possibility that the beneficial effect of angiotensin-converting enzyme inhibitors or AT₁ receptor blockers in heart failure may in part be attributable to an inhibition of myocyte loss. Recently, atrial natriuretic factor (ANF) was shown to increase the apoptotic index from 4.8% to 19% in isolated neonatal cardiomyocytes.²¹⁵ Because ANF levels are elevated in heart failure, sensitivity of cardiomyocytes to ANF may be of pathophysiological importance. In addition, reexpression of the ANF gene in hypertrophied ventricular cardiomyocytes may expose these cells to markedly increased local levels of ANF and thus may promote transition from myocardial hypertrophy to heart failure by inducing apoptotic cell loss. However, it is somewhat counterintuitive to assume that ANF is produced at high levels in the atrial and fetal ventricular myocytes, and there is no evidence of apoptosis so far reported in these cells in vivo.

Apoptosis in Ischemic Heart Disease
Although myocardial infarction was long considered to be characterized by nonapoptotic ("necrotic") cell death due to the breakdown of cellular energy metabolism, there is growing evidence that myocyte loss during the acute stage of myocardial infarction involves both apoptotic and nonapoptotic cell death.^216–218 In human postmortem studies of myocardial infarction, apoptotic cardiomyocytes appeared to be predominantly localized in the hypoperfused border zone between the central infarct area and noncompromised myocardial tissue.^218,219 Interestingly, myocytes in the peri-infarct region were shown to upregulate the apoptotic regulatory proteins bax and bcl-2.^71,117 In addition, myocytes showing evidence of DNA degradation, chromatin condensation, and cell fragmentation were detected in human hibernating myocardium.¹⁴ Observation in animal models of myocardial infarction suggest that apoptosis may contribute substantially to cell death even within the central infarct area with 5% to 33% of the cardiomyocytes staining positive for DNA fragmentation.^71,220–222 However, at present, the relative importance of apoptotic and nonapoptotic cell death in both the acute and chronic phases of myocardial infarction is not known. Initial evidence for the potential pathophysiological significance of apoptosis has recently been provided in a rat model of myocardial infarction.²²² Treatment with the caspase inhibitor zVAD.fmk led to a reduction in infarct size and an improvement of acute functional parameters. However, these measurements were obtained 24 hours after infarction, and it is not known whether the beneficial effects of zVAD.fmk persists in the chronic stage.

Ischemia is associated with multiple alterations in the extracellular and intracellular milieu of cardiomyocytes that may act as inducers of apoptosis. So far, a proapoptotic role has only been verified in in vitro experiments for hypoxia, whereas the role of acidosis or elevated adenosine concentrations is not known.^196,223 As hypoxia increases transcriptional transactivation by p53 in neonatal rat ventricular cardiomyocytes, a p53-mediated mechanism for myocyte apoptosis under hypoxic conditions was suggested.^120,196 However, the extent of apoptosis in hypoxic regions after ligation of the left coronary artery in p53-deficient mice was shown to be similar to that in wild-type mice.²²⁰ The death receptor Fas is markedly upregulated in cardiomyocytes during ischemia and hypoxia, and cardiomyocytes may thus become susceptible to apoptotic cell death by interaction with FasL. Whereas under control conditions <1% of cardiomyocytes expressed the Fas antigen, Fas was detectable in >50% of cardiomyocytes within a few hours of ischemia and ischemia/reperfusion.^71,224 It is not known, however, whether FasL, which is essential to trigger apoptotic cell death by a Fas-dependent mechanism, is expressed in the ischemic myocardium.

The role of apoptosis in reperfusion injury has recently been addressed in rat and rabbit animal models, where reperfusion was shown to accelerate the occurrence of apoptotic cell death in cardiomyocytes.^221,225 Because the formation of reactive oxygen species has been implicated as one of the pathomechanisms for tissue injury during reperfusion, the recent finding that oxidative stress induces apoptosis in isolated neonatal rat ventricular cardiomyocytes may provide an important mechanistic link between reperfusion and tissue injury.^179,226

In addition, apoptotic cell death may have a role in the remodeling of noninfarcted myocardium, as evidenced in human myocardial specimens sampled within 10 days after myocardial infarction.²¹⁹ In myocardium remote from the infarcted area, 0.7% of the cardiomyocytes were apoptotic, whereas in control hearts no myocyte apoptosis was detectable. Interestingly, apoptosis in noninfarcted regions of myocardium was inhibited by overexpression of IGF-1 in a transgenic mouse model, resulting in reduced ventricular dilation and wall stress 7 days after infarction.²²⁷ IGF-1 has been shown to activate the antiapoptotic kinase Akt in PC12 cells, but it is not known whether the same mechanism is operative in cardiac myocytes.

Apoptosis and Atherosclerosis
Apoptosis may prove to play an essential role in atherosclerotic alterations of the vessel wall. In human specimens from atherosclerotic lesions of native coronary vessels and saphenous vein grafts, widespread apoptosis was detectable by TUNEL staining (up to 43% of cells in the lipid-rich core of atheromata).^{15–17,72,228,229} Apoptotic cells were often arranged in cell clusters and primarily consisted of macrophages and smooth muscle cells. A substantial number of cells undergoing apoptosis were immunoreactive with a polyclonal antiserum directed against caspase-1 and -3.^228,230 Remarkably, apoptosis did not occur in medial smooth muscle cells.¹⁶ A similar spatial restriction of smooth muscle cell apoptosis to the superficial neointima was observed after denudation of the rat aorta.²³¹ In that model, apoptosis was no longer detectable after reendothelialization.

In contrast to primary atherosclerotic lesions, where apoptosis was not a consistent finding in all specimens, almost all atherectomy specimens from restenotic lesions showed evidence of apoptosis.²²⁹ Apoptosis strongly correlated with the presence of intimal hyperplasia.²²⁹ In a rat model of balloon vascular injury, apoptosis primarily affected neointimal smooth muscle cells 7 to 28 days after dilation.¹⁶ In contrast, Perlman et al²³² found extensive apoptosis of medial smooth muscle cells with 70% TUNEL-positive cells as early as 0.5 to 2 hours after balloon injury in rat carotid and rabbit iliac arteries. The difference in time course between neointimal and medial smooth muscle cell apoptosis suggests that balloon vascular injury may directly induce apoptosis in medial smooth muscle cells, whereas apoptosis of neointimal smooth muscle cells may be associated with the restructuring of the neointima.

Vascular smooth muscle cells undergo p53-dependent apoptosis after overexpression of the positive cell cycle regulators c-myc or E1A.^121,188 Interestingly, isolated vascular smooth muscle cells from human atherosclerotic plaques were shown to have a higher propensity for both spontaneous apoptosis and apoptosis induced by overexpression of p53 compared with vascular smooth muscle cells from normal vessels.^233,234

An alternative mechanism may involve the induction of apoptosis by a death receptor–dependent mechanism. Fas is known to be widely expressed in human atherosclerotic lesions, including a sizable fraction of smooth muscle cells.^18,72 Twenty percent of Fas-positive cells showed evidence for internucleosomal DNA fragmentation with associated morphological features of apoptosis, like chromatin condensation and nuclear fragmentation. Interestingly, cultured aortic smooth muscle cells were not sensitive to a cytotoxic anti-Fas antibody despite Fas expression on one third of the cells.¹⁸ However, pretreatment with -interferon, interleukin-1, and TNF- markedly sensitized smooth muscle cells to Fas-induced apoptosis. These cytokines increased both the fraction of Fas-expressing cells to 90% of all cells and the density of Fas antigen on individual cells. Interestingly, the combination of -interferon, interleukin-1, and TNF- alone already exerted a proapoptotic effect on cultured smooth muscle cells that may involve both NO-dependent and -independent mechanisms.^228,235 These observations underline the importance of inflammatory cytokines generated by activated infiltrating T lymphocytes (-interferon) and macrophages (interleukin-1 and TNF-).²³⁶ Activation of immune cells may involve oxidized low-density lipoprotein (LDL) particles, the cell surface receptor CD40, and its cognate ligand.^237,238 One major clinical implication of apoptotic cell death in atherosclerotic lesions may be a reduced plaque stability. In addition to proteolysis, loss of smooth muscle cells in the fibrous cap of atherosclerotic lesions is known to predispose the lesions to plaque instability and therefore may increase the risk of unstable angina pectoris and acute myocardial infarction.²³⁹ In this respect, it is noteworthy that the death receptor Fas is expressed on as many as two thirds of the cells in the fibrous cap in human atherosclerotic lesions.¹⁸

In recent studies,^240,241 a potential role of oxidative mechanisms has been suggested in the apoptosis of vascular cells. Cultured endothelial cells undergo apoptosis in response to oxidized LDL, indicating a potential role for apoptosis in the early phases of atherogenesis.^240,241 Sensitivity to oxidized LDL could be reduced by nitric oxide or by calcium channel blockers.^241,242 In addition, apoptosis of vascular smooth muscle may at least partly be attributable to oxidant damage by hydrogen peroxide.²⁴³

It is interesting to note that exposure of phosphatidylserine on the surface of apoptotic cells can promote thrombin generation in vitro.²⁴⁴ At present, it is not known whether this mechanism contributes to the thrombogenicity of atherosclerotic lesions in vivo.

Other Cardiovascular Diseases
Apoptosis due to immune mechanisms may be of major importance in myocarditis and cardiac allograft rejection. Indeed, in a rat model of heterotopic heart transplantation, Szabolcs et al²⁴⁵ found extensive apoptosis of cardiomyocytes, endothelial cells, and infiltrating leukocytes. Infiltrating cells consisted initially of lymphocytes, whereas macrophages predominated in later stages, when apoptosis was prominent. It is not known to which extent apoptosis is induced by cytotoxic T lymphocytes through Fas-dependent or granzyme B–dependent mechanisms.

Cardiomyocytes express a functional TNFR1 and can undergo apoptosis after stimulation with TNF- in vitro.^35,246,247 Interestingly, TNF- was shown to be produced in myocardium, although the cell type was not clearly defined.²⁴⁸ When TNF- was highly overexpressed under the control of a strong cardiomyocyte-specific promoter, a phenotype of dilated cardiomyopathy was induced in transgenic mice.²⁴⁹ Likewise, in an animal model of myocarditis, TNF- was shown to exert a major role in the pathogenesis of myocardial inflammation, although it is not clear in how far TNF-–mediated apoptosis contributed to myocardial damage.^250,251

9. Future Directions

Basic research in apoptosis has made a tremendous progress within the past few years and will undoubtedly provide exciting new insights in the near future. Accumulating evidence that apoptosis may be an important feature of several cardiovascular diseases will certainly increase the interest in apoptosis in cardiovascular research. In this respect, several points appear to deserve further investigation. First, although apoptosis has been verified histologically in heart failure, acute myocardial infarction, and atherosclerosis, the role of apoptosis in the pathogenesis of these conditions requires substantiation. It is important to determine whether apoptosis is one of the early causes rather than a terminal event that is associated with the end stage of these disease entities. Second, the true incidence of apoptosis is not clear, with reported values ranging from 0.2% to 35% in heart failure. Concerns about the specificity of TUNEL staining have been raised. In addition, TUNEL staining and morphometry are laborious, and the duration of apoptotic cells being detectable by TUNEL may last only a few hours. DNA laddering, though specific, is not quantitative and sensitive in tissue samples, where a small number of cells (<1%) are undergoing apoptosis. Therefore, we need to improve or develop detection techniques that allow for accurate quantitative detection of apoptosis in cardiovascular tissue. Third, to date, the initiating stimuli of apoptosis in myocardial and vascular cells at the cellular level are not well understood. Recognition of the inducing mechanisms could open up ways to inhibit cell death in cardiovascular tissues and possibly help to define targets for future drug design. Fourth, although end-stage events of apoptosis, such as the activation of downstream caspases (caspase-3, -6, and -7) are likely to be essentially uniform in all cell types, some regulatory mechanisms may be unique to cells in cardiovascular tissues. Elucidation of proapoptotic and antiapoptotic mechanisms in cardiomyocytes and vascular smooth muscle cells could delineate potential targets for intervention. Fifth, although pharmacological caspase inhibition prevents myocyte apoptosis induced by ischemia and reperfusion in short-term experiments,²²² the ultimate fate of the cells is not clear. It is not known whether ischemic myocytes that have initiated the apoptosis pathway and are acutely rescued by caspase inhibition will eventually survive or whether the drug simply delays cell death. Sixth, with respect to the clinical situation, the role of apoptosis as a prognostic marker deserves further study. For example, it remains to be determined whether the degree of apoptosis could provide additional prognostic information in patients with impaired left ventricular function and thus help in therapeutic decision making. Seventh, attempts are being made to induce myocyte proliferation as a potential therapeutic approach for heart failure. However, cardiomyocyte apoptosis in response to forced cell cycle reentry may limit the feasibility of this approach. Clarification of the apoptotic mechanisms involved will therefore be of major importance. Finally, initial attempts to reduce neointima formation by inducing apoptosis through adenoviral gene transfer have been promising in animal models of balloon vascular injury.^252,253 Likewise, induced apoptosis of smooth muscle cells was associated with a regression of both neointimal and primary atheromatous lesions in rabbits.¹¹⁹ However, further studies are required to evaluate the potential clinical benefit of this approach, as apoptosis of vascular smooth muscle cells may reduce plaque stability and thus initiate acute coronary events.²³⁹

Taken together, apoptosis increasingly penetrates the field of cardiovascular research. Several exciting hypotheses need to be tested to determine whether the opportunities offered by the modulation of apoptotic cell death will finally translate into new treatment approaches for cardiovascular disease.

Selected Abbreviations and Acronyms

AIF = apoptosis-inducing factor ANF = atrial natriuretic factor apaf = apoptotic protease-activating factor ARC = apoptosis repressor with caspase recruitment domain BH = bcl-2 homology CASH = caspase homologue CD = cluster of differentiation DED = death effector domain DR = death receptor ERK = extracellular signal–regulated kinase FADD = Fas-associated death domain protein FasL = Fas ligand FLAME-1 = FADD-like antiapoptotic molecule FLICE = FADD-homologous ICE/Ced-3-like protease FLIP = FLICE-inhibitory proteins IB = inhibitor of NFB I-FLICE = inhibitor of FLICE IAP = inhibitor of apoptosis protein ICE = interleukin-1ß–converting enzyme IGF = insulin-like growth factor JNK = c-Jun N-terminal kinase MAPK = mitogen-activated protein kinase MEK = MAPK/ERK kinase MEKK = MEK kinase NFB = nuclear factor B NGF = nerve growth factor PI-3 kinase = phosphatidylinositol-3 kinase PKB, PKC = protein kinase B and C RAIDD = RIP-associated ICH-1/Ced-3-homologous death domain protein RIP = receptor-interaction protein SAPK = stress-activated protein kinase SEK = SAPK/ERK kinase TdT = terminal deoxynucleotidyltransferase TNF = tumor necrosis factor TNFR = TNF receptor TRADD = TNFR-associated death domain protein TRAF = TNFR-associated factor TRAIL = TNF-related apoptosis-inducing ligand TUNEL = TdT-mediated dUTP nick end-labeling zVAD.fmk = benzyloxycarbonyl-valine-alanine-aspartate fluoromethylketone

Appendix 1

Glossary
Bcl-2 Family Proteins
This class of proteins shows homology to the C elegans protein ced-9. The first member of this protein family was named B-cell lymphoma 2 gene (bcl-2), because it proved to induce lymphomas in humans when activated by chromosome translocation. In mammalian species, both proapoptotic and antiapoptotic members of this protein family have been characterized. Bcl-2 family proteins are localized to the outer mitochondrial and nuclear membranes and to the membrane of the endoplasmic reticulum.

Caspases
Caspases are intracellular apoptosis-associated proteases that cleave substrate proteins behind aspartate residues. They characteristically contain a cysteine residue in the catalytic center.

ced-3, ced-4, and ced-9
Programmed cell death of a defined set of cells is an inherent feature in the development of the nematode C elegans. Genetic analysis of mutants with disturbances in developmental cell death identified a group of cell death genes (ced). Apart from genes involved in the removal of dead cells, the genes ced-3, ced-4, and ced-9 proved to be instrumental in the execution and regulation of programmed cell death. Characterization of these genes was seminal in the understanding of genes involved in the apoptosis of mammalian cells, such as caspases (ced-3), apaf-1 (ced-4), and bcl-2–related proteins (ced-9).

Death Receptors
Death receptors are a class of cell membrane receptors belonging to the larger group of TNF receptors. Death receptors are characterized by an intracytoplasmic death domain of 80 amino acid residues. Members of this group comprise Fas, TNFR1, DR3, DR4, and DR5. The cognate ligands are Fas ligand (FasL), tumor necrosis factor- (TNF-), Apo-3L, and TNF-related apoptosis-inducing ligand (TRAIL) for Fas, TNFR1, DR3, and DR4/5, respectively.

Fas
Fas, the prototypical death receptor, mediates apoptotic cell death after stimulation by Fas ligand. Receptor activation involves the recruitment of adaptor proteins to the cell membrane and subsequent caspase activation.

Inhibitor of Apoptosis Proteins
Inhibitor of apoptosis proteins (IAPs) are a class of antiapoptotic proteins that were initially isolated in baculovirus, a virus infecting insect cells. Mammalian homologues are believed to inhibit apoptosis by direct caspase inhibition and by mediating survival signals after TNFR stimulation.

p53
p53 is a transcriptional transactivator protein that is involved in cell cycle control and DNA repair. p53 has been implicated in apoptosis induced by genotoxic agents and deregulated cell cycle control.

Acknowledgments

Dr Haunstetter is supported by a grant from the Deutsche Forschungsgemeinschaft (Ha 2606/1-1). The authors would like to thank Hiroki Aoki, Peter Kang, and Tetsuo Shioi for critical reading of the manuscript and helpful discussion.

Received December 3, 1997; accepted April 7, 1998.

References

1. Kerr JF, Wyllie AH, Currie AR. Apoptosis: a basic biological phenomenon with wide-ranging implications in tissue kinetics. Br J Cancer. 1972;26:239–257.[Medline] [Order article via Infotrieve]

2. Majno G, Joris I. Apoptosis, oncosis, and necrosis: an overview of cell death. Am J Pathol. 1995;146:3–15.[Abstract]

3. Yeh ET. Life and death in the cardiovascular system. Circulation. 1997;95:782–786.[Free Full Text]

4. MacLellan WR, Schneider MD. Death by design: programmed cell death in cardiovascular biology and disease. Circ Res. 1997;81:137–144.[Abstract/Free Full Text]

5. Nagata S. Apoptosis by death factor. Cell. 1997;88:355–365.[Medline] [Order article via Infotrieve]

6. Nicholson DW, Thornberry NA. Caspases: killer proteases. Trends Biochem Sci. 1997;22:299–306.[Medline] [Order article via Infotrieve]

7. Reed JC. Double identity for proteins of the Bcl-2 family. Nature. 1997;387:773–776.[Medline] [Order article via Infotrieve]

8. Porter AG, Ng P, Janicke RU. Death substrates come alive. Bioessays. 1997;19:501–507.[Medline] [Order article via Infotrieve]

9. Petit PX, Lecoeur H, Zorn E, Dauguet C, Mignotte B, Gougeon ML. Alterations in mitochondrial structure and function are early events of dexamethasone-induced thymocyte apoptosis. J Cell Biol. 1995;130:157–167.[Abstract/Free Full Text]

10. Zamzami N, Marchetti P, Castedo M, Zanin C, Vayssiere JL, Petit PX, Kroemer G. Reduction in mitochondrial potential constitutes an early irreversible step of programmed lymphocyte death in vivo. J Exp Med. 1995;181:1661–1672.[Abstract/Free Full Text]

11. Martin SJ, Green DR. Protease activation during apoptosis: death by a thousand cuts? Cell. 1995;82:349–352.[Medline] [Order article via Infotrieve]

12. Bennett MR, Gibson DF, Schwartz SM, Tait JF. Binding and phagocytosis of apoptotic vascular smooth muscle cells is mediated in part by exposure of phosphatidylserine. Circ Res. 1995;77:1136–1142.[Abstract/Free Full Text]

13. Liu Y, Cigola E, Cheng W, Kajstura J, Olivetti G, Hintze TH, Anversa P. Myocyte nuclear mitotic division and programmed myocyte cell death characterize the cardiac myopathy induced by rapid ventricular pacing in dogs. Lab Invest. 1995;73:771–787.[Medline] [Order article via Infotrieve]

14. Elsasser A, Schlepper M, Klovekorn WP, Cai WJ, Zimmermann R, Muller KD, Strasser R, Kostin S, Gagel C, Munkel B, Schaper W, Schaper J. Hibernating myocardium: an incomplete adaptation to ischemia. Circulation. 1997;96:2920–2931.[Abstract/Free Full Text]

15. Kockx MM, Cambier BA, Bortier HE, De Meyer GR, Declercq SC, van Cauwelaert PA, Bultinck J. Foam cell replication and smooth muscle cell apoptosis in human saphenous vein grafts. Histopathology. 1994;25:365–371.[Medline] [Order article via Infotrieve]

16. Han DK, Haudenschild CC, Hong MK, Tinkle BT, Leon MB, Liau G. Evidence for apoptosis in human atherogenesis and in a rat vascular injury model. Am J Pathol. 1995;147:267–277.[Abstract]

17. Bjorkerud S, Bjorkerud B. Apoptosis is abundant in human atherosclerotic lesions, especially in inflammatory cells (macrophages and T cells), and may contribute to the accumulation of gruel and plaque instability. Am J Pathol. 1996;149:367–380.[Abstract]

18. Geng YJ, Henderson LE, Levesque EB, Muszynski M, Libby P. Fas is expressed in human atherosclerotic intima and promotes apoptosis of cytokine-primed human vascular smooth muscle cells. Arterioscler Thromb Vasc Biol. 1997;17:2200–2208.[Abstract/Free Full Text]

19. Fadok VA, Savill JS, Haslett C, Bratton DL, Doherty DE, Campbell PA, Henson PM. Different populations of macrophages use either the vitronectin receptor or the phosphatidylserine receptor to recognize and remove apoptotic cells. J Immunol. 1992;149:4029–4035.[Abstract]

20. Zwaal RF, Schroit AJ. Pathophysiologic implications of membrane phospholipid asymmetry in blood cells. Blood. 1997;89:1121–1132.[Free Full Text]

21. Savill J, Dransfield I, Hogg N, Haslett C. Vitronectin receptor-mediated phagocytosis of cells undergoing apoptosis. Nature. 1990;343:170–173.[Medline] [Order article via Infotrieve]

22. Hall SE, Savill JS, Henson PM, Haslett C. Apoptotic neutrophils are phagocytosed by fibroblasts with participation of the fibroblast vitronectin receptor and involvement of a mannose/fucose-specific lectin. J Immunol. 1994;153:3218–3227.[Abstract]

23. Martin SJ, Reutelingsperger CP, McGahon AJ, Rader JA, van Schie RC, LaFace DM, Green DR. Early redistribution of plasma membrane phosphatidylserine is a general feature of apoptosis regardless of the initiating stimulus: inhibition by overexpression of Bcl-2 and Abl. J Exp Med. 1995;182:1545–1556.[Abstract/Free Full Text]

23A. Savill J. Apoptosis. Phagocytic docking without shocking. Nature. 1998;392:442–443.[Medline] [Order article via Infotrieve]

24. Geng YJ. Regulation of programmed cell death or apoptosis in atherosclerosis. Heart Vessels. 1997;suppl 12:76–80.

25. Wyllie AH. Glucocorticoid-induced thymocyte apoptosis is associated with endogenous endonuclease activation. Nature. 1980;284:555–556.[Medline] [Order article via Infotrieve]

26. Enari M, Sakahira H, Yokoyama H, Okawa K, Iwamatsu A, Nagata S. A caspase-activated DNase that degrades DNA during apoptosis, and its inhibitor ICAD. Nature. 1998;391:43–50.[Medline] [Order article via Infotrieve]

27. Brown DG, Sun XM, Cohen GM. Dexamethasone-induced apoptosis involves cleavage of DNA to large fragments prior to internucleosomal fragmentation. J Biol Chem. 1993;268:3037–3039.[Abstract/Free Full Text]

28. Oberhammer F, Wilson JW, Dive C, Morris ID, Hickman JA, Wakeling AE, Walker PR, Sikorska M. Apoptotic death in epithelial cells: cleavage of DNA to 300 and/or 50 kb fragments prior to or in the absence of internucleosomal fragmentation. EMBO J. 1993;12:3679–3684.[Medline] [Order article via Infotrieve]

29. Gavrieli Y, Sherman Y, Ben-Sasson SA. Identification of programmed cell death in situ via specific labeling of nuclear DNA fragmentation. J Cell Biol. 1992;119:493–501.[Abstract/Free Full Text]

30. Wijsman JH, Jonker RR, Keijzer R, van de Velde CJ, Cornelisse CJ, van Dierendonck JH. A new method to detect apoptosis in paraffin sections: in situ end-labeling of fragmented DNA. J Histochem Cytochem. 1993;41:7–12.[Abstract]

31. Mundle SD, Gao XZ, Khan S, Gregory SA, Preisler HD, Raza A. Two in situ labeling techniques reveal different patterns of DNA fragmentation during spontaneous apoptosis in vivo and induced apoptosis in vitro. Anticancer Res. 1995;15:1895–1904.[Medline] [Order article via Infotrieve]

32. Eastman A, Barry MA. The origins of DNA breaks: a consequence of DNA damage, DNA repair, or apoptosis? Cancer Invest. 1992;10:229–240.[Medline] [Order article via Infotrieve]

33. Gold R, Schmied M, Giegerich G, Breitschopf H, Hartung HP, Toyka KV, Lassmann H. Differentiation between cellular apoptosis and necrosis by the combined use of in situ tailing and nick translation techniques. Lab Invest. 1994;71:219–225.[Medline] [Order article via Infotrieve]

34. Fairbairn DW, Olive PL, O'Neill KL. The comet assay: a comprehensive review. Mutat Res. 1995;339:37–59.[Medline] [Order article via Infotrieve]

35. Krown KA, Page MT, Nguyen C, Zechner D, Gutierrez V, Comstock KL, Glembotski CC, Quintana PJ, Sabbadini RA. Tumor necrosis factor alpha-induced apoptosis in cardiac myocytes: involvement of the sphingolipid signaling cascade in cardiac cell death. J Clin Invest. 1996;98:2854–2865.[Medline] [Order article via Infotrieve]

36. Lazebnik YA, Kaufmann SH, Desnoyers S, Poirier GG, Earnshaw WC. Cleavage of poly(ADP-ribose) polymerase by a proteinase with properties like ICE. Nature. 1994;371:346–347.[Medline] [Order article via Infotrieve]

37. Alnemri ES, Livingston DJ, Nicholson DW, Salvesen G, Thornberry NA, Wong WW, Yuan J. Human ICE/CED-3 protease nomenclature. Cell. 1996;87:171.[Medline] [Order article via Infotrieve]

38. Walker NP, Talanian RV, Brady KD, Dang LC, Bump NJ, Ferenz CR, Franklin S, Ghayur T, Hackett MC, Hammill LD, et al. Crystal structure of the cysteine protease interleukin-1 beta-converting enzyme: a (p20/p10)2 homodimer. Cell. 1994;78:343–352.[Medline] [Order article via Infotrieve]

39. Wilson KP, Black JA, Thomson JA, Kim EE, Griffith JP, Navia MA, Murcko MA, Chambers SP, Aldape RA, Raybuck SA, et al. Structure and mechanism of interleukin-1 beta converting enzyme. Nature. 1994;370:270–275.[Medline] [Order article via Infotrieve]

40. Yuan J, Shaham S, Ledoux S, Ellis HM, Horvitz HR. The C. elegans cell death gene ced-3 encodes a protein similar to mammalian interleukin-1 beta-converting enzyme. Cell. 1993;75:641–652.[Medline] [Order article via Infotrieve]

41. Kuida K, Lippke JA, Ku G, Harding MW, Livingston DJ, Su MS, Flavell RA. Altered cytokine export and apoptosis in mice deficient in interleukin-1 beta converting enzyme. Science. 1995;267:2000–2003.[Abstract/Free Full Text]

42. Kuida K, Zheng TS, Na S, Kuan C, Yang D, Karasuyama H, Rakic P, Flavell RA. Decreased apoptosis in the brain and premature lethality in CPP32-deficient mice. Nature. 1996;384:368–372.[Medline] [Order article via Infotrieve]

43. Thornberry NA, Rano TA, Peterson EP, Rasper DM, Timkey T, Garcia-Calvo M, Houtzager VM, Nordstrom PA, Roy S, Vaillancourt JP, Chapman KT, Nicholson DW. A combinatorial approach defines specificities of members of the caspase family and granzyme B: functional relationships established for key mediators of apoptosis. J Biol Chem. 1997;272:17907–17911.[Abstract/Free Full Text]

44. Enari M, Talanian RV, Wong WW, Nagata S. Sequential activation of ICE-like and CPP32-like proteases during Fas-mediated apoptosis. Nature. 1996;380:723–726.[Medline] [Order article via Infotrieve]

45. Muzio M, Chinnaiyan AM, Kischkel FC, O'Rourke K, Shevchenko A, Ni J, Scaffidi C, Bretz JD, Zhang M, Gentz R, Mann M, Krammer PH, Peter ME, Dixit VM. FLICE, a novel FADD-homologous ICE/CED-3-like protease, is recruited to the CD95 (Fas/APO-1) death–inducing signaling complex. Cell. 1996;85:817–827.[Medline] [Order article via Infotrieve]

46. Boldin MP, Goncharov TM, Goltsev YV, Wallach D. Involvement of MACH, a novel MORT1/FADD-interacting protease, in Fas/APO-1-and TNF receptor-induced cell death. Cell. 1996;85:803–815.[Medline] [Order article via Infotrieve]

47. Duan H, Dixit VM. RAIDD is a new "death" adaptor molecule. Nature. 1997;385:86–89.[Medline] [Order article via Infotrieve]

48. Ahmad M, Srinivasula SM, Wang L, Talanian RV, Litwack G, Fernandes-Alnemri T, Alnemri ES. CRADD, a novel human apoptotic adaptor molecule for caspase-2, and FasL/tumor necrosis factor receptor-interacting protein RIP. Cancer Res. 1997;57:615–619.[Abstract/Free Full Text]

49. Srinivasula SM, Ahmad M, Fernandes-Alnemri T, Litwack G, Alnemri ES. Molecular ordering of the Fas-apoptotic pathway: the Fas/APO-1 protease Mch5 is a CrmA-inhibitable protease that activates multiple Ced-3/ICE-like cysteine proteases. Proc Natl Acad Sci U S A. 1996;93:14486–14491.[Abstract/Free Full Text]

50. Fernandes-Alnemri T, Armstrong RC, Krebs J, Srinivasula SM, Wang L, Bullrich F, Fritz LC, Trapani JA, Tomaselli KJ, Litwack G, Alnemri ES. In vitro activation of CPP32 and Mch3 by Mch4, a novel human apoptotic cysteine protease containing two FADD-like domains. Proc Natl Acad Sci U S A. 1996;93:7464–7469.[Abstract/Free Full Text]

51. Cardone MH, Salvesen GS, Widmann C, Johnson G, Frisch SM. The regulation of anoikis: MEKK-1 activation requires cleavage by caspases. Cell. 1997;90:315–323.[Medline] [Order article via Infotrieve]

52. Kothakota S, Azuma T, Reinhard C, Klippel A, Tang J, Chu K, McGarry TJ, Kirschner MW, Koths K, Kwiatkowski DJ, Williams LT. Caspase-3-generated fragment of gelsolin: effector of morphological change in apoptosis. Science. 1997;278:294–298.[Abstract/Free Full Text]

53. Sakahira H, Enari M, Nagata S. Cleavage of CAD inhibitor in CAD activation and DNA degradation during apoptosis. Nature. 1998;391:96–99.[Medline] [Order article via Infotrieve]

54. Orth K, Chinnaiyan AM, Garg M, Froelich CJ, Dixit VM. The CED-3/ICE-like protease Mch2 is activated during apoptosis and cleaves the death substrate lamin A. J Biol Chem. 1996;271:16443–16446.[Abstract/Free Full Text]

55. Takahashi A, Alnemri ES, Lazebnik YA, Fernandes-Alnemri T, Litwack G, Moir RD, Goldman RD, Poirier GG, Kaufmann SH, Earnshaw WC. Cleavage of lamin A by Mch2 alpha but not CPP32: multiple interleukin 1 beta-converting enzyme-related proteases with distinct substrate recognition properties are active in apoptosis. Proc Natl Acad Sci U S A. 1996;93:8395–8400.[Abstract/Free Full Text]

56. Jacobson MD, Burne JF, Raff MC. Programmed cell death and Bcl-2 protection in the absence of a nucleus. EMBO J. 1994;13:1899–1910.[Medline] [Order article via Infotrieve]

57. Liu X, Zou H, Slaughter C, Wang X. DFF, a heterodimeric protein that functions downstream of caspase-3 to trigger DNA fragmentation during apoptosis. Cell. 1997;89:175–184.[Medline] [Order article via Infotrieve]

58. Lazebnik YA, Takahashi A, Moir RD, Goldman RD, Poirier GG, Kaufmann SH, Earnshaw WC. Studies of the lamin proteinase reveal multiple parallel biochemical pathways during apoptotic execution. Proc Natl Acad Sci U S A. 1995;92:9042–9046.[Abstract/Free Full Text]

59. Zheng L, Fisher G, Miller RE, Peschon J, Lynch DH, Lenardo MJ. Induction of apoptosis in mature T cells by tumour necrosis factor. Nature. 1995;377:348–351.[Medline] [Order article via Infotrieve]

60. Suda T, Takahashi T, Golstein P, Nagata S. Molecular cloning and expression of the Fas ligand, a novel member of the tumor necrosis factor family. Cell. 1993;75:1169–1178.[Medline] [Order article via Infotrieve]

61. Pitti RM, Marsters SA, Ruppert S, Donahue CJ, Moore A, Ashkenazi A. Induction of apoptosis by Apo-2 ligand, a new member of the tumor necrosis factor cytokine family. J Biol Chem. 1996;271:12687–12690.[Abstract/Free Full Text]

61A. Marsters SA, Sheridan JP, Pitti RM, Brush J, Goddard A, Ashkenazi A. Identification of a ligand for the death-domain-containing receptor Apo3. Curr Biol. 1998;8:525–528.[Medline] [Order article via Infotrieve]

62. Itoh N, Yonehara S, Ishii A, Yonehara M, Mizushima S, Sameshima M, Hase A, Seto Y, Nagata S. The polypeptide encoded by the cDNA for human cell surface antigen Fas can mediate apoptosis. Cell. 1991;66:233–243.[Medline] [Order article via Infotrieve]

63. Loetscher H, Pan YC, Lahm HW, Gentz R, Brockhaus M, Tabuchi H, Lesslauer W. Molecular cloning and expression of the human 55 kd tumor necrosis factor receptor. Cell. 1990;61:351–359.[Medline] [Order article via Infotrieve]

64. Chinnaiyan AM, O'Rourke K, Yu GL, Lyons RH, Garg M, Duan DR, Xing L, Gentz R, Ni J, Dixit VM. Signal transduction by DR3, a death domain-containing receptor related to TNFR-1 and CD95. Science. 1996;274:990–992.[Abstract/Free Full Text]

65. Kitson J, Raven T, Jiang YP, Goeddel DV, Giles KM, Pun KT, Grinham CJ, Brown R, Farrow SN. A death-domain-containing receptor that mediates apoptosis. Nature. 1996;384:372–375.[Medline] [Order article via Infotrieve]

66. Pan G, O'Rourke K, Chinnaiyan AM, Gentz R, Ebner R, Ni J, Dixit VM. The receptor for the cytotoxic ligand TRAIL. Science. 1997;276:111–113.[Abstract/Free Full Text]

67. Walczak H, Degli-Esposti MA, Johnson RS, Smolak PJ, Waugh JY, Boiani N, Timour MS, Gerhart MJ, Schooley KA, Smith CA, Goodwin RG, Rauch CT. TRAIL-R2: a novel apoptosis-mediating receptor for TRAIL. EMBO J. 1997;16:5386–5397.[Medline] [Order article via Infotrieve]

68. Itoh N, Nagata S. A novel protein domain required for apoptosis: mutational analysis of human Fas antigen. J Biol Chem. 1993;268:10932–10937.[Abstract/Free Full Text]

69. Tartaglia LA, Ayres TM, Wong GH, Goeddel DV. A novel domain within the 55 kd TNF receptor signals cell death. Cell. 1993;74:845–853.[Medline] [Order article via Infotrieve]

70. Watanabe-Fukunaga R, Brannan CI, Itoh N, Yonehara S, Copeland NG, Jenkins NA, Nagata S. The cDNA structure, expression, and chromosomal assignment of the mouse Fas antigen. J Immunol. 1992;148:1274–1279.[Abstract]

71. Kajstura J, Cheng W, Reiss K, Clark WA, Sonnenblick EH, Krajewski S, Reed JC, Olivetti G, Anversa P. Apoptotic and necrotic myocyte cell deaths are independent contributing variables of infarct size in rats. Lab Invest. 1996;74:86–107.[Medline] [Order article via Infotrieve]

72. Cai W, Devaux B, Schaper W, Schaper J. The role of Fas/APO 1 and apoptosis in the development of human atherosclerotic lesions. Atherosclerosis. 1997;131:177–186.[Medline] [Order article via Infotrieve]

73. Adachi M, Suematsu S, Kondo T, Ogasawara J, Tanaka T, Yoshida N, Nagata S. Targeted mutation in the Fas gene causes hyperplasia in peripheral lymphoid organs and liver. Nat Genet. 1995;11:294–300.[Medline] [Order article via Infotrieve]

74. Watanabe-Fukunaga R, Brannan CI, Copeland NG, Jenkins NA, Nagata S. Lymphoproliferation disorder in mice explained by defects in Fas antigen that mediates apoptosis. Nature. 1992;356:314–317.[Medline] [Order article via Infotrieve]

75. Takahashi T, Tanaka M, Brannan CI, Jenkins NA, Copeland NG, Suda T, Nagata S. Generalized lymphoproliferative disease in mice, caused by a point mutation in the Fas ligand. Cell. 1994;76:969–976.[Medline] [Order article via Infotrieve]

76. Drappa J, Vaishnaw AK, Sullivan KE, Chu JL, Elkon KB. Fas gene mutations in the Canale-Smith syndrome, an inherited lymphoproliferative disorder associated with autoimmunity. N Engl J Med. 1996;335:1643–1649.[Abstract/Free Full Text]

77. Chinnaiyan AM, O'Rourke K, Tewari M, Dixit VM. FADD, a novel death domain-containing protein, interacts with the death domain of Fas and initiates apoptosis. Cell. 1995;81:505–512.[Medline] [Order article via Infotrieve]

78. Hsu H, Xiong J, Goeddel DV. The TNF receptor 1-associated protein TRADD signals cell death and NF-kappa B activation. Cell. 1995;81:495–504.[Medline] [Order article via Infotrieve]

79. Hsu H, Shu HB, Pan MG, Goeddel DV. TRADD-TRAF2 and TRADD-FADD interactions define two distinct TNF receptor 1 signal transduction pathways. Cell. 1996;84:299–308.[Medline] [Order article via Infotrieve]

80. Yeh WC, Shahinian A, Speiser D, Kraunus J, Billia F, Wakeham A, de la Pompa JL, Ferrick D, Hum B, Iscove N, Ohashi P, Rothe M, Goeddel DV, Mak TW. Early lethality, functional NF-kappaB activation, and increased sensitivity to TNF-induced cell death in TRAF2-deficient mice. Immunity. 1997;7:715–725.[Medline] [Order article via Infotrieve]

80A. Yeh WC, Pompa JL, McCurrach ME, Shu HB, Elia AJ, Shahinian A, Ng M, Wakeham A, Khoo W, Mitchell K, El-Deiry WS, Lowe SW, Goeddel DV, Mak TW. FADD: essential for embryo development and signaling from some, but not all, inducers of apoptosis. Science. 1998;279:1954–1958.[Abstract/Free Full Text]

81. Stanger BZ, Leder P, Lee TH, Kim E, Seed B. RIP: a novel protein containing a death domain that interacts with Fas/APO-1 (CD95) in yeast and causes cell death. Cell. 1995;81:513–523.[Medline] [Order article via Infotrieve]

82. Hsu H, Huang J, Shu HB, Baichwal V, Goeddel DV. TNF-dependent recruitment of the protein kinase RIP to the TNF receptor-1 signaling complex. Immunity. 1996;4:387–396.[Medline] [Order article via Infotrieve]

83. Longthorne VL, Williams GT. Caspase activity is required for commitment to Fas-mediated apoptosis. EMBO J. 1997;16:3805–3812.[Medline] [Order article via Infotrieve]

84. Nagata S. Apoptosis: telling cells their time is up. Curr Biol. 1996;6:1241–1243.[Medline] [Order article via Infotrieve]

85. Liu X, Kim CN, Yang J, Jemmerson R, Wang X. Induction of apoptotic program in cell-free extracts: requirement for dATP and cytochrome c. Cell. 1996;86:147–157.[Medline] [Order article via Infotrieve]

86. Yang J, Liu X, Bhalla K, Kim CN, Ibrado AM, Cai J, Peng TI, Jones DP, Wang X. Prevention of apoptosis by Bcl-2: release of cytochrome c from mitochondria blocked. Science. 1997;275:1129–1132.[Abstract/Free Full Text]

87. Kluck RM, Bossy-Wetzel E, Green DR, Newmeyer DD. The release of cytochrome c from mitochondria: a primary site for Bcl-2 regulation of apoptosis. Science. 1997;275:1132–1136.[Abstract/Free Full Text]

88. Kluck RM, Martin SJ, Hoffman BM, Zhou JS, Green DR, Newmeyer DD. Cytochrome c activation of CPP32-like proteolysis plays a critical role in a Xenopus cell-free apoptosis system. EMBO J. 1997;16:4639–4649.[Medline] [Order article via Infotrieve]

89. Vander Heiden MG, Chandel NS, Williamson EK, Schumacker PT, Thompson CB. Bcl-xL regulates the membrane potential and volume homeostasis of mitochondria. Cell. 1997;91:627–637.[Medline] [Order article via Infotrieve]

90. Zou H, Henzel WJ, Liu X, Lutschg A, Wang X. Apaf-1, a human protein homologous to C. elegans CED-4, participates in cytochrome c-dependent activation of caspase-3. Cell. 1997;90:405–413.[Medline] [Order article via Infotrieve]

91. Li P, Nijhawan D, Budihardjo I, Srinivasula SM, Ahmad M, Alnemri ES, Wang X. Cytochrome c and ATP-dependent formation of Apaf-1/Caspase-9 complex initiates an apoptotic protease cascade. Cell. 1997;91:479–489.[Medline] [Order article via Infotrieve]

92. Zamzami N, Susin SA, Marchetti P, Hirsch T, Gomez-Monterrey I, Castedo M, Kroemer G. Mitochondrial control of nuclear apoptosis. J Exp Med. 1996;183:1533–1544.[Abstract/Free Full Text]

93. Susin SA, Zamzami N, Castedo M, Hirsch T, Marchetti P, Macho A, Daugas E, Geuskens M, Kroemer G. Bcl-2 inhibits the mitochondrial release of an apoptogenic protease. J Exp Med. 1996;184:1331–1341.[Abstract/Free Full Text]

94. Zoratti M, Szabo I. The mitochondrial permeability transition. Biochim Biophys Acta. 1995;1241:139–176.[Medline] [Order article via Infotrieve]

95. Weil M, Jacobson MD, Coles HS, Davies TJ, Gardner RL, Raff KD, Raff MC. Constitutive expression of the machinery for programmed cell death. J Cell Biol. 1996;133:1053–1059.[Abstract/Free Full Text]

96. Ellis HM, Horvitz HR. Genetic control of programmed cell death in the nematode C. elegans. Cell. 1986;44:817–829.[Medline] [Order article via Infotrieve]

97. Cleary ML, Smith SD, Sklar J. Cloning and structural analysis of cDNAs for bcl-2 and a hybrid bcl-2/immunoglobulin transcript resulting from the t(14;18) translocation. Cell. 1986;47:19–28.[Medline] [Order article via Infotrieve]

98. Vaux DL, Weissman IL, Kim SK. Prevention of programmed cell death in Caenorhabditis elegans by human bcl-2. Science. 1992;258:1955–1957.[Abstract/Free Full Text]

99. Vaux DL, Cory S, Adams JM. Bcl-2 gene promotes haemopoietic cell survival and cooperates with c-myc to immortalize pre-B cells. Nature. 1988;335:440–442.[Medline] [Order article via Infotrieve]

100. Boise LH, Gonzalez-Garcia M, Postema CE, Ding L, Lindsten T, Turka LA, Mao X, Nunez G, Thompson CB. bcl-x, a bcl-2-related gene that functions as a dominant regulator of apoptotic cell death. Cell. 1993;74:597–608.[Medline] [Order article via Infotrieve]

101. Gibson L, Holmgreen SP, Huang DC, Bernard O, Copeland NG, Jenkins NA, Sutherland GR, Baker E, Adams JM, Cory S. bcl-w, a novel member of the bcl-2 family, promotes cell survival. Oncogene. 1996;13:665–675.[Medline] [Order article via Infotrieve]

102. Lin EY, Orlofsky A, Wang HG, Reed JC, Prystowsky MB. A1, a Bcl-2 family member, prolongs cell survival and permits myeloid differentiation. Blood. 1996;87:983–992.[Abstract/Free Full Text]

103. Oltvai ZN, Milliman CL, Korsmeyer SJ. Bcl-2 heterodimerizes in vivo with a conserved homolog, Bax, that accelerates programmed cell death. Cell. 1993;74:609–619.[Medline] [Order article via Infotrieve]

104. Farrow SN, White JH, Martinou I, Raven T, Pun KT, Grinham CJ, Martinou JC, Brown R. Cloning of a bcl-2 homologue by interaction with adenovirus E1B 19K. Nature. 1995;374:731–733.[Medline] [Order article via Infotrieve]

105. Chittenden T, Harrington EA, O'Connor R, Flemington C, Lutz RJ, Evan GI, Guild BC. Induction of apoptosis by the Bcl-2 homologue Bak. Nature. 1995;374:733–736.[Medline] [Order article via Infotrieve]

106. Kiefer MC, Brauer MJ, Powers VC, Wu JJ, Umansky SR, Tomei LD, Barr PJ. Modulation of apoptosis by the widely distributed Bcl-2 homologue Bak. Nature. 1995;374:736–739.[Medline] [Order article via Infotrieve]

107. Yang E, Zha J, Jockel J, Boise LH, Thompson CB, Korsmeyer SJ. Bad, a heterodimeric partner for Bcl-XL and Bcl-2, displaces Bax and promotes cell death. Cell. 1995;80:285–291.[Medline] [Order article via Infotrieve]

108. Boyd JM, Gallo GJ, Elangovan B, Houghton AB, Malstrom S, Avery BJ, Ebb RG, Subramanian T, Chittenden T, Lutz RJ, et al. Bik, a novel death-inducing protein, shares a distinct sequence motif with Bcl-2 family proteins and interacts with viral and cellular survival-promoting proteins. Oncogene. 1995;11:1921–1928.[Medline] [Order article via Infotrieve]

109. Inohara N, Ding L, Chen S, Nunez G. Harakiri, a novel regulator of cell death, encodes a protein that activates apoptosis and interacts selectively with survival-promoting proteins Bcl-2 and Bcl-X(L). EMBO J. 1997;16:1686–1694.[Medline] [Order article via Infotrieve]

110. Wang K, Yin XM, Chao DT, Milliman CL, Korsmeyer SJ. BID: a novel BH3 domain-only death agonist. Genes Dev. 1996;10:2859–2869.[Abstract/Free Full Text]

111. Veis DJ, Sorenson CM, Shutter JR, Korsmeyer SJ. Bcl-2-deficient mice demonstrate fulminant lymphoid apoptosis, polycystic kidneys, and hypopigmented hair. Cell. 1993;75:229–240.[Medline] [Order article via Infotrieve]

112. Kamada S, Shimono A, Shinto Y, Tsujimura T, Takahashi T, Noda T, Kitamura Y, Kondoh H, Tsujimoto Y. bcl-2 deficiency in mice leads to pleiotropic abnormalities: accelerated lymphoid cell death in thymus and spleen, polycystic kidney, hair hypopigmentation, and distorted small intestine. Cancer Res. 1995;55:354–359.[Abstract/Free Full Text]

113. Nakayama K, Nakayama K, Negishi I, Kuida K, Shinkai Y, Louie MC, Fields LE, Lucas PJ, Stewart V, Alt FW, et al. Disappearance of the lymphoid system in Bcl-2 homozygous mutant chimeric mice. Science. 1993;261:1584–1588.[Abstract/Free Full Text]

114. Nakayama K, Nakayama K, Negishi I, Kuida K, Sawa H, Loh DY. Targeted disruption of Bcl-2 alpha beta in mice: occurrence of gray hair, polycystic kidney disease, and lymphocytopenia. Proc Natl Acad Sci U S A. 1994;91:3700–3704.[Abstract/Free Full Text]

115. Motoyama N, Wang F, Roth KA, Sawa H, Nakayama K, Nakayama K, Negishi I, Senju S, Zhang Q, Fujii S, et al. Massive cell death of immature hematopoietic cells and neurons in Bcl-x-deficient mice. Science. 1995;267:1506–1510.[Abstract/Free Full Text]

116. Knudson CM, Tung KS, Tourtellotte WG, Brown GA, Korsmeyer SJ. Bax-deficient mice with lymphoid hyperplasia and male germ cell death. Science. 1995;270:96–99.[Abstract/Free Full Text]

117. Misao J, Hayakawa Y, Ohno M, Kato S, Fujiwara T, Fujiwara H. Expression of bcl-2 protein, an inhibitor of apoptosis, and Bax, an accelerator of apoptosis, in ventricular myocytes of human hearts with myocardial infarction. Circulation. 1996;94:1506–1512.[Abstract/Free Full Text]

118. Olivetti G, Abbi R, Quaini F, Kajstura J, Cheng W, Nitahara JA, Quaini E, Di Loreto C, Beltrami CA, Krajewski S, Reed JC, Anversa P. Apoptosis in the failing human heart. N Engl J Med. 1997;336:1131–1141.[Abstract/Free Full Text]

119. Pollman MJ, Hall JL, Mann MJ, Zhang L, Gibbons GH. Inhibition of neointimal cell bcl-x expression induces apoptosis and regression of vascular disease. Nat Med. 1998;4:222–227.[Medline] [Order article via Infotrieve]

120. Kirshenbaum LA, de Moissac D. The bcl-2 gene product prevents programmed cell death of ventricular myocytes. Circulation. 1997;96:1580–1585.[Abstract/Free Full Text]

121. Bennett MR, Evan GI, Schwartz SM. Apoptosis of rat vascular smooth muscle cells is regulated by p53-dependent and -independent pathways. Circ Res. 1995;77:266–273.[Abstract/Free Full Text]

122. Zha H, Aime-Sempe C, Sato T, Reed JC. Proapoptotic protein Bax heterodimerizes with Bcl-2 and homodimerizes with Bax via a novel domain (BH3) distinct from BH1 and BH2. J Biol Chem. 1996;271:7440–7444.[Abstract/Free Full Text]

123. Chittenden T, Flemington C, Houghton AB, Ebb RG, Gallo GJ, Elangovan B, Chinnadurai G, Lutz RJ. A conserved domain in Bak, distinct from BH1 and BH2, mediates cell death and protein binding functions. EMBO J. 1995;14:5589–5596.[Medline] [Order article via Infotrieve]

124. Jacobson MD, Burne JF, King MP, Miyashita T, Reed JC, Raff MC. Bcl-2 blocks apoptosis in cells lacking mitochondrial DNA. Nature. 1993;361:365–369.[Medline] [Order article via Infotrieve]

125. Nguyen M, Branton PE, Walton PA, Oltvai ZN, Korsmeyer SJ, Shore GC. Role of membrane anchor domain of Bcl-2 in suppression of apoptosis caused by E1B-defective adenovirus. J Biol Chem. 1994;269:16521–16524.[Abstract/Free Full Text]

126. Muchmore SW, Sattler M, Liang H, Meadows RP, Harlan JE, Yoon HS, Nettesheim D, Chang BS, Thompson CB, Wong SL, Ng SL, Fesik SW. X-ray and NMR structure of human Bcl-xL, an inhibitor of programmed cell death. Nature. 1996;381:335–341.[Medline] [Order article via Infotrieve]

127. Minn AJ, Velez P, Schendel SL, Liang H, Muchmore SW, Fesik SW, Fill M, Thompson CB. Bcl-x(L) forms an ion channel in synthetic lipid membranes. Nature. 1997;385:353–357.[Medline] [Order article via Infotrieve]

128. Hockenbery DM, Oltvai ZN, Yin XM, Milliman CL, Korsmeyer SJ. Bcl-2 functions in an antioxidant pathway to prevent apoptosis. Cell. 1993;75:241–251.[Medline] [Order article via Infotrieve]

129. Jacobson MD, Raff MC. Programmed cell death and Bcl-2 protection in very low oxygen. Nature. 1995;374:814–816.[Medline] [Order article via Infotrieve]

130. Chinnaiyan AM, Orth K, O'Rourke K, Duan H, Poirier GG, Dixit VM. Molecular ordering of the cell death pathway: Bcl-2 and Bcl-xL function upstream of the CED-3-like apoptotic proteases. J Biol Chem. 1996;271:4573–4576.[Abstract/Free Full Text]

131. Armstrong RC, Aja T, Xiang J, Gaur S, Krebs JF, Hoang K, Bai X, Korsmeyer SJ, Karanewsky DS, Fritz LC, Tomaselli KJ. Fas-induced activation of the cell death-related protease CPP32 is inhibited by Bcl-2 and by ICE family protease inhibitors. J Biol Chem. 1996;271:16850–16855.[Abstract/Free Full Text]

132. Chinnaiyan AM, O'Rourke K, Lane BR, Dixit VM. Interaction of CED-4 with CED-3 and CED-9: a molecular framework for cell death. Science. 1997;275:1122–1126.[Abstract/Free Full Text]

133. Wu D, Wallen HD, Inohara N, Nunez G. Interaction and regulation of the Caenorhabditis elegans death protease CED-3 by CED-4 and CED-9. J Biol Chem. 1997;272:21449–21454.[Abstract/Free Full Text]

134. Shaham S, Horvitz HR. Developing Caenorhabditis elegans neurons may contain both cell-death protective and killer activities. Genes Dev. 1996;10:578–591.[Abstract/Free Full Text]

135. Tao W, Kurschner C, Morgan JI. Modulation of cell death in yeast by the Bcl-2 family of proteins. J Biol Chem. 1997;272:15547–15552.[Abstract/Free Full Text]

136. Birnbaum MJ, Clem RJ, Miller LK. An apoptosis-inhibiting gene from a nuclear polyhedrosis virus encoding a polypeptide with Cys/His sequence motifs. J Virol. 1994;68:2521–2528.[Abstract/Free Full Text]

137. Roy N, Mahadevan MS, McLean M, Shutler G, Yaraghi Z, Farahani R, Baird S, Besner-Johnston A, Lefebvre C, Kang X, et al. The gene for neuronal apoptosis inhibitory protein is partially deleted in individuals with spinal muscular atrophy. Cell. 1995;80:167–178.[Medline] [Order article via Infotrieve]

138. Uren AG, Pakusch M, Hawkins CJ, Puls KL, Vaux DL. Cloning and expression of apoptosis inhibitory protein homologs that function to inhibit apoptosis and/or bind tumor necrosis factor receptor-associated factors. Proc Natl Acad Sci U S A. 1996;93:4974–4978.[Abstract/Free Full Text]

139. Ambrosini G, Adida C, Altieri DC. A novel anti-apoptosis gene, survivin, expressed in cancer and lymphoma. Nat Med. 1997;3:917–921.[Medline] [Order article via Infotrieve]

140. Rothe M, Pan MG, Henzel WJ, Ayres TM, Goeddel DV. The TNFR2-TRAF signaling complex contains two novel proteins related to baculoviral inhibitor of apoptosis proteins. Cell. 1995;83:1243–1252.[Medline] [Order article via Infotrieve]

141. Chu ZL, McKinsey TA, Liu L, Gentry JJ, Malim MH, Ballard DW. Suppression of tumor necrosis factor-induced cell death by inhibitor of apoptosis c-IAP2 is under NF-kappaB control. Proc Natl Acad Sci U S A. 1997;94:10057–10062.[Abstract/Free Full Text]

142. Devereaux QL, Takahashi R, Salvesen GS, Reed JC. X-linked IAP is a direct inhibitor of cell-death proteases. Nature. 1997;388:300–304.[Medline] [Order article via Infotrieve]

143. Roy N, Deveraux QL, Takahashi R, Salvesen GS, Reed JC. The c-IAP-1 and c-IAP-2 proteins are direct inhibitors of specific caspases. EMBO J. 1997;16:6914–6925.[Medline] [Order article via Infotrieve]

144. Bertin J, Armstrong RC, Ottilie S, Martin DA, Wang Y, Banks S, Wang GH, Senkevich TG, Alnemri ES, Moss B, Lenardo MJ, Tomaselli KJ, Cohen JI. Death effector domain-containing herpesvirus and poxvirus proteins inhibit both Fas- and TNFR1-induced apoptosis. Proc Natl Acad Sci U S A. 1997;94:1172–1176.[Abstract/Free Full Text]

145. Thome M, Schneider P, Hofmann K, Fickenscher H, Meinl E, Neipel F, Mattmann C, Burns K, Bodmer JL, Schroter M, Scaffidi C, Krammer PH, Peter ME, Tschopp J. Viral FLICE-inhibitory proteins (FLIPs) prevent apoptosis induced by death receptors. Nature. 1997;386:517–521.[Medline] [Order article via Infotrieve]

146. Irmler M, Thome M, Hahne M, Schneider P, Hofmann K, Steiner V, Bodmer JL, Schroter M, Burns K, Mattmann C, Rimoldi D, French LE, Tschopp J. Inhibition of death receptor signals by cellular FLIP. Nature. 1997;388:190–195.[Medline] [Order article via Infotrieve]

147. Hu S, Vincenz C, Ni J, Gentz R, Dixit VM. I-FLICE, a novel inhibitor of tumor necrosis factor receptor-1- and CD-95-induced apoptosis. J Biol Chem. 1997;272:17255–17257.[Abstract/Free Full Text]

148. Goltsev YV, Kovalenko AV, Arnold E, Varfolomeev EE, Brodianskii VM, Wallach D. CASH, a novel caspase homologue with death effector domains. J Biol Chem. 1997;272:19641–19644.[Abstract/Free Full Text]

149. Srinivasula SM, Ahmad M, Ottilie S, Bullrich F, Banks S, Wang Y, Fernandes-Alnemri T, Croce CM, Litwack G, Tomaselli KJ, Armstrong RC, Alnemri ES. FLAME-1, a novel FADD-like anti-apoptotic molecule that regulates Fas/TNFR1-induced apoptosis. J Biol Chem. 1997;272:18542–18545.[Abstract/Free Full Text]

149A. Koseki T, Inohara N, Chen S, Nunez G. ARC, an inhibitor of apoptosis expressed in skeletal muscle and heart that interacts selectively with caspases. Proc Natl Acad Sci U S A. 1998;95:5156–5160.[Abstract/Free Full Text]

150. Sheridan JP, Marsters SA, Pitti RM, Gurney A, Skubatch M, Baldwin D, Ramakrishnan L, Gray CL, Baker K, Wood WI, Goddard AD, Godowski P, Ashkenazi A. Control of TRAIL-induced apoptosis by a family of signaling and decoy receptors. Science. 1997;277:818–821.[Abstract/Free Full Text]

151. Nishigaki K, Minatoguchi S, Seishima M, Asano K, Noda T, Yasuda N, Sano H, Kumada H, Takemura M, Noma A, Tanaka T, Watanabe S, Fujiwara H. Plasma Fas ligand, an inducer of apoptosis, and plasma soluble Fas, an inhibitor of apoptosis, in patients with chronic congestive heart failure. J Am Coll Cardiol. 1997;29:1214–1220.[Abstract]

152. Ferrari R, Bachetti T, Confortini R, Opasich C, Febo O, Corti A, Cassani G, Visioli O. Tumor necrosis factor soluble receptors in patients with various degrees of congestive heart failure. Circulation. 1995;92:1479–1486.[Abstract/Free Full Text]

153. Baeuerle PA, Baltimore D. NF-kappa B: ten years after. Cell. 1996;87:13–20.[Medline] [Order article via Infotrieve]

154. Liu ZG, Hsu H, Goeddel DV, Karin M. Dissection of TNF receptor 1 effector functions: JNK activation is not linked to apoptosis while NF-kappaB activation prevents cell death. Cell. 1996;87:565–576.[Medline] [Order article via Infotrieve]

155. Wang CY, Mayo MW, Baldwin AS Jr. TNF- and cancer therapy-induced apoptosis: potentiation by inhibition of NF-kappaB. Science. 1996;274:784–787.[Abstract/Free Full Text]

156. Van Antwerp DJ, Martin SJ, Kafri T, Green DR, Verma IM. Suppression of TNF-alpha-induced apoptosis by NF-kappaB. Science. 1996;274:787–789.[Abstract/Free Full Text]

157. Beg AA, Baltimore D. An essential role for NF-kappaB in preventing TNF-alpha-induced cell death. Science. 1996;274:782–784.[Abstract/Free Full Text]

158. Beg AA, Sha WC, Bronson RT, Ghosh S, Baltimore D. Embryonic lethality and liver degeneration in mice lacking the RelA component of NF-kappa B. Nature. 1995;376:167–170.[Medline] [Order article via Infotrieve]

159. Yao R, Cooper GM. Requirement for phosphatidylinositol-3 kinase in the prevention of apoptosis by nerve growth factor. Science. 1995;267:2003–2006.[Abstract/Free Full Text]

160. Parrizas M, Saltiel AR, LeRoith D. Insulin-like growth factor 1 inhibits apoptosis using the phosphatidylinositol 3'-kinase and mitogen-activated protein kinase pathways. J Biol Chem. 1997;272:154–161.[Abstract/Free Full Text]

161. Dudek H, Datta SR, Franke TF, Birnbaum MJ, Yao R, Cooper GM, Segal RA, Kaplan DR, Greenberg ME. Regulation of neuronal survival by the serine-threonine protein kinase Akt. Science. 1997;275:661–665.[Abstract/Free Full Text]

162. Kauffmann-Zeh A, Rodriguez-Viciana P, Ulrich E, Gilbert C, Coffer P, Downward J, Evan G. Suppression of c-Myc-induced apoptosis by Ras signalling through PI(3)K and PKB. Nature. 1997;385:544–548.[Medline] [Order article via Infotrieve]

163. Franke TF, Kaplan DR, Cantley LC. PI3K: downstream AKTion blocks apoptosis. Cell. 1997;88:435–437.[Medline] [Order article via Infotrieve]

164. Datta SR, Dudek H, Tao X, Masters S, Fu H, Gotoh Y, Greenberg ME. Akt phosphorylation of BAD couples survival signals to the cell-intrinsic death machinery. Cell. 1997;91:231–241.[Medline] [Order article via Infotrieve]

165. Zha J, Harada H, Yang E, Jockel J, Korsmeyer SJ. Serine phosphorylation of death agonist BAD in response to survival factor results in binding to 14–3-3 not BCL-X(L). Cell. 1996;87:619–628.[Medline] [Order article via Infotrieve]

166. Sugden PH, Bogoyevitch MA. Intracellular signalling through protein kinases in the heart. Cardiovasc Res. 1995;30:478–492.[Medline] [Order article via Infotrieve]

167. Force T, Pombo CM, Avruch JA, Bonventre JV, Kyriakis JM. Stress-activated protein kinases in cardiovascular disease. Circ Res. 1996;78:947–953.[Free Full Text]

168. Xia Z, Dickens M, Raingeaud J, Davis RJ, Greenberg ME. Opposing effects of ERK and JNK-p38 MAP kinases on apoptosis. Science. 1995;270:1326–1331.[Abstract/Free Full Text]

169. Verheij M, Bose R, Lin XH, Yao B, Jarvis WD, Grant S, Birrer MJ, Szabo E, Zon LI, Kyriakis JM, Haimovitz-Friedman A, Fuks Z, Kolesnick RN. Requirement for ceramide-initiated SAPK/JNK signalling in stress-induced apoptosis. Nature. 1996;380:75–79.[Medline] [Order article via Infotrieve]

170. Ham J, Babij C, Whitfield J, Pfarr CM, Lallemand D, Yaniv M, Rubin LL. A c-Jun dominant negative mutant protects sympathetic neurons against programmed cell death. Neuron. 1995;14:927–939.[Medline] [Order article via Infotrieve]

171. Chen YR, Wang X, Templeton D, Davis RJ, Tan TH. The role of c-Jun N-terminal kinase (JNK) in apoptosis induced by ultraviolet C and gamma radiation: duration of JNK activation may determine cell death and proliferation. J Biol Chem. 1996;271:31929–31936.[Abstract/Free Full Text]

172. Zanke BW, Boudreau K, Rubie E, Winnett E, Tibbles LA, Zon L, Kyriakis J, Liu FF, Woodgett JR. The stress-activated protein kinase pathway mediates cell death following injury induced by cis-platinum, UV irradiation or heat. Curr Biol. 1996;6:606–613.[Medline] [Order article via Infotrieve]

173. Wang Y, Huang S, Sah VP, Ross J Jr, Brown JH, Han J, Chien KR. Cardiac muscle cell hypertrophy and apoptosis induced by distinct members of the p38 mitogen-activated protein kinase family. J Biol Chem. 1998;273:2161–2168.[Abstract/Free Full Text]

174. Yang X, Khosravi-Far R, Chang HY, Baltimore D. Daxx, a novel Fas-binding protein that activates JNK and apoptosis. Cell. 1997;89:1067–1076.[Medline] [Order article via Infotrieve]

175. Ichijo H, Nishida E, Irie K, ten Dijke P, Saitoh M, Moriguchi T, Takagi M, Matsumoto K, Miyazono K, Gotoh Y. Induction of apoptosis by ASK1, a mammalian MAPKKK that activates SAPK/JNK and p38 signaling pathways. Science. 1997;275:90–94.[Abstract/Free Full Text]

176. Nishina H, Fischer KD, Radvanyi L, Shahinian A, Hakem R, Rubie EA, Bernstein A, Mak TW, Woodgett JR, Penninger JM. Stress-signalling kinase Sek1 protects thymocytes from apoptosis mediated by CD95 and CD3. Nature. 1997;385:350–353.[Medline] [Order article via Infotrieve]

177. Wang HG, Rapp UR, Reed JC. Bcl-2 targets the protein kinase Raf-1 to mitochondria. Cell. 1996;87:629–638.[Medline] [Order article via Infotrieve]

178. Sheng Z, Knowlton K, Chen J, Hoshijima M, Brown JH, Chien KR. Cardiotrophin 1 (CT-1) inhibition of cardiac myocyte apoptosis via a mitogen-activated protein kinase-dependent pathway: divergence from downstream CT-1 signals for myocardial cell hypertrophy. J Biol Chem. 1997;272:5783–5791.[Abstract/Free Full Text]

179. Aikawa R, Komuro I, Yamazaki T, Zou Y, Kudoh S, Tanaka M, Shiojima I, Hiroi Y, Yazaki Y. Oxidative stress activates extracellular signal-regulated kinases through src and ras in cultured cardiac myocytes of neonatal rats. J Clin Invest. 1997;100:1813–1821.[Medline] [Order article via Infotrieve]

180. Ito T, Deng X, Carr B, May WS. Bcl-2 phosphorylation required for anti-apoptosis function. J Biol Chem. 1997;272:11671–11673.[Abstract/Free Full Text]

181. Horiuchi M, Hayashida W, Kambe T, Yamada T, Dzau VJ. Angiotensin type 2 receptor dephosphorylates Bcl-2 by activating mitogen-activated protein kinase phosphatase-1 and induces apoptosis. J Biol Chem. 1997;272:19022–19026.[Abstract/Free Full Text]

182. Testi R. Sphingomyelin breakdown and cell fate. Trends Biochem Sci. 1996;21:468–471.[Medline] [Order article via Infotrieve]

183. Santana P, Pena LA, Haimovitz-Friedman A, Martin S, Green D, McLoughlin M, Cordon-Cardo C, Schuchman EH, Fuks Z, Kolesnick R. Acid sphingomyelinase-deficient human lymphoblasts and mice are defective in radiation-induced apoptosis. Cell. 1996;86:189–199.[Medline] [Order article via Infotrieve]

184. Lowe SW, Schmitt EM, Smith SW, Osborne BA, Jacks T. p53 is required for radiation-induced apoptosis in mouse thymocytes. Nature. 1993;362:847–849.[Medline] [Order article via Infotrieve]

185. Clarke AR, Purdie CA, Harrison DJ, Morris RG, Bird CC, Hooper ML, Wyllie AH. Thymocyte apoptosis induced by p53-dependent and independent pathways. Nature. 1993;362:849–852.[Medline] [Order article via Infotrieve]

186. Rao L, Debbas M, Sabbatini P, Hockenbery D, Korsmeyer S, White E. The adenovirus E1A proteins induce apoptosis, which is inhibited by the E1B 19-kDa and Bcl-2 proteins. Proc Natl Acad Sci U S A. 1992;89:7742–7746.[Abstract/Free Full Text]

187. Evan GI, Wyllie AH, Gilbert CS, Littlewood TD, Land H, Brooks M, Waters CM, Penn LZ, Hancock DC. Induction of apoptosis in fibroblasts by c-myc protein. Cell. 1992;69:119–128.[Medline] [Order article via Infotrieve]

188. Bennett MR, Evan GI, Newby AC. Deregulated expression of the c-myc oncogene abolishes inhibition of proliferation of rat vascular smooth muscle cells by serum reduction, interferon-gamma, heparin, and cyclic nucleotide analogues and induces apoptosis. Circ Res. 1994;74:525–536.[Abstract/Free Full Text]

189. Sofer-Levi Y, Resnitzky D. Apoptosis induced by ectopic expression of cyclin D1 but not cyclin E. Oncogene. 1996;13:2431–2437.[Medline] [Order article via Infotrieve]

190. Kirshenbaum LA, Schneider MD. Adenovirus E1A represses cardiac gene transcription and reactivates DNA synthesis in ventricular myocytes, via alternative pocket protein- and p300-binding domains. J Biol Chem. 1995;270:7791–7794.[Abstract/Free Full Text]

191. Kirshenbaum LA, Abdellatif M, Chakraborty S, Schneider MD. Human E2F-1 reactivates cell cycle progression in ventricular myocytes and represses cardiac gene transcription. Dev Biol. 1996;179:402–411.[Medline] [Order article via Infotrieve]

192. Agah R, Kirshenbaum LA, Abdellatif M, Truong LD, Chakraborty S, Michael LH, Schneider MD. Adenoviral delivery of E2F-1 directs cell cycle reentry and p53-independent apoptosis in postmitotic adult myocardium in vivo. J Clin Invest. 1997;100:2722–2728.[Medline] [Order article via Infotrieve]

193. Debbas M, White E. Wild-type p53 mediates apoptosis by E1A, which is inhibited by E1B. Genes Dev. 1993;7:546–554.[Abstract/Free Full Text]

194. Hermeking H, Eick D. Mediation of c-Myc-induced apoptosis by p53. Science. 1994;265:2091–2093.[Abstract/Free Full Text]

195. Qin XQ, Livingston DM, Kaelin WG Jr, Adams PD. Deregulated transcription factor E2F-1 expression leads to S-phase entry and p53-mediated apoptosis. Proc Natl Acad Sci U S A. 1994;91:10918–10922.[Abstract/Free Full Text]

196. Long X, Boluyt MO, Hipolito ML, Lundberg MS, Zheng JS, O'Neill L, Cirielli C, Lakatta EG, Crow MT. p53 and the hypoxia-induced apoptosis of cultured neonatal rat cardiac myocytes. J Clin Invest. 1997;99:2635–2643.[Medline] [Order article via Infotrieve]

197. Ko LJ, Prives C. p53: puzzle and paradigm. Genes Dev. 1996;10:1054–1072.[Free Full Text]

198. Miyashita T, Reed JC. Tumor suppressor p53 is a direct transcriptional activator of the human bax gene. Cell. 1995;80:293–299.[Medline] [Order article via Infotrieve]

199. Friedlander P, Haupt Y, Prives C, Oren M. A mutant p53 that discriminates between p53-responsive genes cannot induce apoptosis. Mol Cell Biol. 1996;16:4961–4971.[Abstract]

200. Ludwig RL, Bates S, Vousden KH. Differential activation of target cellular promoters by p53 mutants with impaired apoptotic function. Mol Cell Biol. 1996;16:4952–4960.[Abstract]

201. Polyak K, Xia Y, Zweier JL, Kinzler KW, Vogelstein B. A model for p53-induced apoptosis. Nature. 1997;389:300–305.[Medline] [Order article via Infotrieve]

202. Pexieder T. Cell death in the morphogenesis and teratogenesis of the heart. Adv Anat Embryol Cell Biol. 1975;51:3–99.

203. Takeda K, Yu ZX, Nishikawa T, Tanaka M, Hosoda S, Ferrans VJ, Kasajima T. Apoptosis and DNA fragmentation in the bulbus cordis of the developing rat heart. J Mol Cell Cardiol. 1996;28:209–215.[Medline] [Order article via Infotrieve]

204. James TN. Normal and abnormal consequences of apoptosis in the human heart: from postnatal morphogenesis to paroxysmal arrhythmias. Circulation. 1994;90:556–573.[Abstract/Free Full Text]

205. James TN, St. Martin E, Willis PW III, Lohr TO. Apoptosis as a possible cause of gradual development of complete heart block and fatal arrhythmias associated with absence of the AV node, sinus node, and internodal pathways. Circulation. 1996;93:1424–1438.[Abstract/Free Full Text]

206. Weber KT, Brilla CG. Pathological hypertrophy and cardiac interstitium: fibrosis and renin-angiotensin-aldosterone system. Circulation. 1991;83:1849–1865.[Abstract/Free Full Text]

207. Davies CH, Davia K, Bennett JG, Pepper JR, Poole-Wilson PA, Harding SE. Reduced contraction and altered frequency response of isolated ventricular myocytes from patients with heart failure. Circulation. 1995;92:2540–2549.[Abstract/Free Full Text]

208. Kajstura J, Zhang X, Liu Y, Szoke E, Cheng W, Olivetti G, Hintze TH, Anversa P. The cellular basis of pacing-induced dilated cardiomyopathy: myocyte cell loss and myocyte cellular reactive hypertrophy. Circulation. 1995;92:2306–2317.[Abstract/Free Full Text]

209. Sharov VG, Sabbah HN, Shimoyama H, Goussev AV, Lesch M, Goldstein S. Evidence of cardiocyte apoptosis in myocardium of dogs with chronic heart failure. Am J Pathol. 1996;148:141–149.[Abstract]

210. Narula J, Haider N, Virmani R, DiSalvo TG, Kolodgie FD, Hajjar RJ, Schmidt U, Semigran MJ, Dec GW, Khaw BA. Apoptosis in myocytes in end-stage heart failure. N Engl J Med. 1996;335:1182–1189.[Abstract/Free Full Text]

211. Mallat Z, Tedgui A, Fontaliran F, Frank R, Durigon M, Fontaine G. Evidence of apoptosis in arrhythmogenic right ventricular dysplasia. N Engl J Med. 1996;335:1190–1196.[Abstract/Free Full Text]

212. Cheng W, Li B, Kajstura J, Li P, Wolin MS, Sonnenblick EH, Hintze TH, Olivetti G, Anversa P. Stretch-induced programmed myocyte cell death. J Clin Invest. 1995;96:2247–2259.

213. Teiger E, Than VD, Richard L, Wisnewsky C, Tea BS, Gaboury L, Tremblay J, Schwartz K, Hamet P. Apoptosis in pressure overload-induced heart hypertrophy in the rat. J Clin Invest. 1996;97:2891–2897.[Medline] [Order article via Infotrieve]

214. Kajstura J, Cigola E, Malhotra A, Li P, Cheng W, Meggs LG, Anversa P. Angiotensin II induces apoptosis of adult ventricular myocytes in vitro. J Mol Cell Cardiol. 1997;29:859–870.[Medline] [Order article via Infotrieve]

215. Wu CF, Bishopric NH, Pratt RE. Atrial natriuretic peptide induces apoptosis in neonatal rat cardiac myocytes. J Biol Chem. 1997;272:14860–14866.[Abstract/Free Full Text]

216. Itoh G, Tamura J, Suzuki M, Suzuki Y, Ikeda H, Koike M, Nomura M, Jie T, Ito K. DNA fragmentation of human infarcted myocardial cells demonstrated by the nick end labeling method and DNA agarose gel electrophoresis. Am J Pathol. 1995;146:1325–1331.[Abstract]

217. Bardales RH, Hailey LS, Xie SS, Schaefer RF, Hsu SM. In situ apoptosis assay for the detection of early acute myocardial infarction. Am J Pathol. 1996;149:821–829.[Abstract]

218. Saraste A, Pulkki K, Kallajoki M, Henriksen K, Parvinen M, Voipio-Pulkki LM. Apoptosis in human acute myocardial infarction. Circulation. 1997;95:320–323.[Abstract/Free Full Text]

219. Olivetti G, Quaini F, Sala R, Lagrasta C, Corradi D, Bonacina E, Gambert SR, Cigola E, Anversa P. Acute myocardial infarction in humans is associated with activation of programmed myocyte cell death in the surviving portion of the heart. J Mol Cell Cardiol. 1996;28:2005–2016.[Medline] [Order article via Infotrieve]

220. Bialik S, Geenen DL, Sasson IE, Cheng R, Horner JW, Evans SM, Lord EM, Koch CJ, Kitsis RN. Myocyte apoptosis during acute myocardial infarction in the mouse localizes to hypoxic regions but occurs independently of p53. J Clin Invest. 1997;100:1363–1372.[Medline] [Order article via Infotrieve]

221. Fliss H, Gattinger D. Apoptosis in ischemic and reperfused rat myocardium. Circ Res. 1996;79:949–956.[Abstract/Free Full Text]

222. Yaoita H, Ogawa K, Maehara K, Maruyama Y. Attenuation of ischemia/reperfusion injury in rats by a caspase inhibitor. Circulation. 1998;97:276–281.[Abstract/Free Full Text]

223. Tanaka M, Ito H, Adachi S, Akimoto H, Nishikawa T, Kasajima T, Marumo F, Hiroe M. Hypoxia induces apoptosis with enhanced expression of Fas antigen messenger RNA in cultured neonatal rat cardiomyocytes. Circ Res. 1994;75:426–433.[Abstract/Free Full Text]

224. Yue TL, Ma XL, Wang X, Romanic AM, Liu GL, Louden C, Gu JL, Kumar S, Poste G, Ruffolo RR Jr, Feuerstein GZ. Possible involvement of stress-activated protein kinase signaling pathway and Fas receptor expression in prevention of ischemia/reperfusion-induced cardiomyocyte apoptosis by carvedilol. Circ Res. 1998;82:166–174.[Abstract/Free Full Text]

225. Gottlieb RA, Burleson KO, Kloner RA, Babior BM, Engler RL. Reperfusion injury induces apoptosis in rabbit cardiomyocytes. J Clin Invest. 1994;94:1621–1628.

226. Jeroudi MO, Hartley CJ, Bolli R. Myocardial reperfusion injury: role of oxygen radicals and potential therapy with antioxidants. Am J Cardiol. 1994;73:2B–7B.[Medline] [Order article via Infotrieve]

227. Li Q, Li B, Wang X, Leri A, Jana KP, Liu Y, Kajstura J, Baserga R, Anversa P. Overexpression of insulin-like growth factor-1 in mice protects from myocyte death after infarction, attenuating ventricular dilation, wall stress, and cardiac hypertrophy. J Clin Invest. 1997;100:1991–1999.[Medline] [Order article via Infotrieve]

228. Geng YJ, Libby P. Evidence for apoptosis in advanced human atheroma: colocalization with interleukin-1 beta-converting enzyme. Am J Pathol. 1995;147:251–266.[Abstract]

229. Isner JM, Kearney M, Bortman S, Passeri J. Apoptosis in human atherosclerosis and restenosis. Circulation. 1995;91:2703–2711.[Abstract/Free Full Text]

230. Mallat Z, Ohan J, Leseche G, Tedgui A. Colocalization of CPP-32 with apoptotic cells in human atherosclerotic plaques. Circulation. 1997;96:424–428.[Abstract/Free Full Text]

231. Bochaton-Piallat ML, Gabbiani F, Redard M, Desmouliere A, Gabbiani G. Apoptosis participates in cellularity regulation during rat aortic intimal thickening. Am J Pathol. 1995;146:1059–1064.[Abstract]

232. Perlman H, Maillard L, Krasinski K, Walsh K. Evidence for the rapid onset of apoptosis in medial smooth muscle cells after balloon injury. Circulation. 1997;95:981–987.[Abstract/Free Full Text]

233. Bennett MR, Littlewood TD, Schwartz SM, Weissberg PL. Increased sensitivity of human vascular smooth muscle cells from atherosclerotic plaques to p53-mediated apoptosis. Circ Res. 1997;81:591–599.[Abstract/Free Full Text]

234. Bennett MR, Evan GI, Schwartz SM. Apoptosis of human vascular smooth muscle cells derived from normal vessels and coronary atherosclerotic plaques. J Clin Invest. 1995;95:2266–2274.

235. Geng YJ, Wu Q, Muszynski M, Hansson GK, Libby P. Apoptosis of vascular smooth muscle cells induced by in vitro stimulation with interferon-gamma, tumor necrosis factor-alpha, and interleukin-1 beta. Arterioscler Thromb Vasc Biol. 1996;16:19–27.[Abstract/Free Full Text]

236. Libby P, Hansson GK. Involvement of the immune system in human atherogenesis: current knowledge and unanswered questions. Lab Invest. 1991;64:5–15.[Medline] [Order article via Infotrieve]

237. Huang YH, Ronnelid J, Frostegard J. Oxidized LDL induces enhanced antibody formation and MHC class II-dependent IFN-gamma production in lymphocytes from healthy individuals. Arterioscler Thromb Vasc Biol. 1995;15:1577–1583.[Abstract/Free Full Text]

238. Mach F, Schonbeck U, Sukhova GK, Bourcier T, Bonnefoy JY, Pober JS, Libby P. Functional CD40 ligand is expressed on human vascular endothelial cells, smooth muscle cells, and macrophages: implications for CD40-CD40 ligand signaling in atherosclerosis. Proc Natl Acad Sci U S A. 1997;94:1931–1936.[Abstract/Free Full Text]

239. Lee RT, Libby P. The unstable atheroma. Arterioscler Thromb Vasc Biol. 1997;17:1859–1867.[Free Full Text]

240. Dimmeler S, Haendeler J, Galle J, Zeiher AM. Oxidized low-density lipoprotein induces apoptosis of human endothelial cells by activation of CPP32-like proteases: a mechanistic clue to the "response to injury" hypothesis. Circulation. 1997;95:1760–1763.[Abstract/Free Full Text]

241. Escargueil-Blanc I, Meilhac O, Pieraggi MT, Arnal JF, Salvayre R, Negre-Salvayre A. Oxidized LDLs induce massive apoptosis of cultured human endothelial cells through a calcium-dependent pathway: prevention by aurintricarboxylic acid. Arterioscler Thromb Vasc Biol. 1997;17:331–339.[Abstract/Free Full Text]

242. Dimmeler S, Haendeler J, Nehls M, Zeiher AM. Suppression of apoptosis by nitric oxide via inhibition of interleukin-1beta-converting enzyme (ICE)-like and cysteine protease protein (CPP)-32-like proteases. J Exp Med. 1997;185:601–607.[Abstract/Free Full Text]

243. Li PF, Dietz R, von Harsdorf R. Differential effect of hydrogen peroxide and superoxide anion on apoptosis and proliferation of vascular smooth muscle cells. Circulation. 1997;96:3602–3609.[Abstract/Free Full Text]

244. Flynn PD, Byrne CD, Baglin TP, Weissberg PL, Bennett MR. Thrombin generation by apoptotic vascular smooth muscle cells. Blood. 1997;89:4378–4384.[Abstract/Free Full Text]

245. Szabolcs M, Michler RE, Yang X, Aji W, Roy D, Athan E, Sciacca RR, Minanov OP, Cannon PJ. Apoptosis of cardiac myocytes during cardiac allograft rejection: relation to induction of nitric oxide synthase. Circulation. 1996;94:1665–1673.[Abstract/Free Full Text]

246. Torre-Amione G, Kapadia S, Lee J, Bies RD, Lebovitz R, Mann DL. Expression and functional significance of tumor necrosis factor receptors in human myocardium. Circulation. 1995;92:1487–1493.[Abstract/Free Full Text]

247. Torre-Amione G, Kapadia S, Lee J, Durand JB, Bies RD, Young JB, Mann DL. Tumor necrosis factor-alpha and tumor necrosis factor receptors in the failing human heart. Circulation. 1996;93:704–711.[Abstract/Free Full Text]

248. Kapadia S, Lee J, Torre-Amione G, Birdsall HH, Ma TS, Mann DL. Tumor necrosis factor-alpha gene and protein expression in adult feline myocardium after endotoxin administration. J Clin Invest. 1995;96:1042–1052.

249. Kubota T, McTiernan CF, Frye CS, Slawson SE, Lemster BH, Koretsky AP, Demetris AJ, Feldman AM. Dilated cardiomyopathy in transgenic mice with cardiac-specific overexpression of tumor necrosis factor-alpha. Circ Res. 1997;81:627–635.[Abstract/Free Full Text]

250. Bachmaier K, Pummerer C, Kozieradzki I, Pfeffer K, Mak TW, Neu N, Penninger JM. Low-molecular-weight tumor necrosis factor receptor p55 controls induction of autoimmune heart disease. Circulation. 1997;95:655–661.[Abstract/Free Full Text]

251. Smith SC, Allen PM. Neutralization of endogenous tumor necrosis factor ameliorates the severity of myosin-induced myocarditis. Circ Res. 1992;70:856–863.[Abstract/Free Full Text]

252. Steg PG, Tahlil O, Aubailly N, Caillaud JM, Dedieu JF, Berthelot K, Le Roux A, Feldman L, Perricaudet M, Denefle P, Branellec D. Reduction of restenosis after angioplasty in an atheromatous rabbit model by suicide gene therapy. Circulation. 1997;96:408–411.[Abstract/Free Full Text]

253. Sata M, Perlman H, Muruve DA, Silver M, Ikebe M, Libermann TA, Oettgen P, Walsh K. Fas ligand gene transfer to the vessel wall inhibits neointima formation and overrides the adenovirus-mediated T cell response. Proc Natl Acad Sci U S A. 1998;95:1213–1217.[Abstract/Free Full Text]

This article has been cited by other articles:

				C. Wu, L. Yan, C. Depre, S. K. Dhar, Y.-T. Shen, J. Sadoshima, S. F. Vatner, and D. E. Vatner Cytochrome c oxidase III as a mechanism for apoptosis in heart failure following myocardial infarction Am J Physiol Cell Physiol, October 1, 2009; 297(4): C928 - C934. [Abstract] [Full Text] [PDF]

				J. F. Garvey, C. T. Taylor, and W. T. McNicholas Cardiovascular disease in obstructive sleep apnoea syndrome: the role of intermittent hypoxia and inflammation Eur. Respir. J., May 1, 2009; 33(5): 1195 - 1205. [Abstract] [Full Text] [PDF]

				K. D. Meyer and L. Zhang Short- and long-term adverse effects of cocaine abuse during pregnancy on the heart development Therapeutic Advances in Cardiovascular Disease, February 1, 2009; 3(1): 7 - 16. [Abstract] [PDF]

				S.-D. Lee, W.-W. Kuo, D.-T. Bau, F.-Y. Ko, F.-L. Wu, C.-H. Kuo, F.-J. Tsai, P. S. Wang, M.-C. Lu, and C.-Y. Huang The coexistence of nocturnal sustained hypoxia and obesity additively increases cardiac apoptosis J Appl Physiol, April 1, 2008; 104(4): 1144 - 1153. [Abstract] [Full Text] [PDF]

				P. S. Tang, M. Mura, R. Seth, and M. Liu Acute lung injury and cell death: how many ways can cells die? Am J Physiol Lung Cell Mol Physiol, April 1, 2008; 294(4): L632 - L641. [Abstract] [Full Text] [PDF]

				H. Soran, N. Younis, P. Currie, J. Silas, I.R. Jones, and G. Gill Influence of diabetes on the maintenance of sinus rhythm after a successful direct current cardioversion in patients with atrial fibrillation QJM, March 1, 2008; 101(3): 181 - 187. [Abstract] [Full Text] [PDF]

				R. M. Mentzer Jr, M. S. Jahania, and R. D. Lasley Myocardial Protection Card. Surg. Adult, January 1, 2008; 3(2008): 443 - 464. [Full Text]

				D. K. Bowles, K. K. Maddali, V. C. Dhulipala, and D. H. Korzick PKC{delta} mediates anti-proliferative, pro-apoptic effects of testosterone on coronary smooth muscle Am J Physiol Cell Physiol, August 1, 2007; 293(2): C805 - C813. [Abstract] [Full Text] [PDF]

				M. F. Chowdhry, H. A. Vohra, and M. Galinanes Diabetes increases apoptosis and necrosis in both ischemic and nonischemic human myocardium: Role of caspases and poly-adenosine diphosphate-ribose polymerase J. Thorac. Cardiovasc. Surg., July 1, 2007; 134(1): 124 - 131. [Abstract] [Full Text] [PDF]

				K. Meyer and Lubo Zhang Fetal Programming of Cardiac Function and Disease Reproductive Sciences, April 1, 2007; 14(3): 209 - 216. [Abstract] [PDF]

				M. Sun, M. Chen, F. Dawood, U. Zurawska, J. Y. Li, T. Parker, Z. Kassiri, L. A. Kirshenbaum, M. Arnold, R. Khokha, et al. Tumor Necrosis Factor-{alpha} Mediates Cardiac Remodeling and Ventricular Dysfunction After Pressure Overload State Circulation, March 20, 2007; 115(11): 1398 - 1407. [Abstract] [Full Text] [PDF]

				L.-L. Yao, Y.-G. Wang, W.-J. Cai, T. Yao, and Y.-C. Zhu Survivin mediates the anti-apoptotic effect of {delta}-opioid receptor stimulation in cardiomyocytes J. Cell Sci., March 1, 2007; 120(5): 895 - 907. [Abstract] [Full Text] [PDF]

				J. Quadrilatero and J. W. E. Rush Increased DNA fragmentation and altered apoptotic protein levels in skeletal muscle of spontaneously hypertensive rats J Appl Physiol, October 1, 2006; 101(4): 1149 - 1161. [Abstract] [Full Text] [PDF]

				E. Gurbanov and X. Shiliang The key role of apoptosis in the pathogenesis and treatment of pulmonary hypertension. Eur. J. Cardiothorac. Surg., September 1, 2006; 30(3): 499 - 507. [Abstract] [Full Text] [PDF]

				R. D. Balsara, F. J. Castellino, and V. A. Ploplis A Novel Function of Plasminogen Activator Inhibitor-1 in Modulation of the AKT Pathway in Wild-type and Plasminogen Activator Inhibitor-1-deficient Endothelial Cells J. Biol. Chem., August 11, 2006; 281(32): 22527 - 22536. [Abstract] [Full Text] [PDF]

				V. Monceau, Y. Belikova, G. Kratassiouk, E. Robidel, F. Russo-Marie, and D. Charlemagne Myocyte apoptosis during acute myocardial infarction in rats is related to early sarcolemmal translocation of annexin A5 in border zone Am J Physiol Heart Circ Physiol, August 1, 2006; 291(2): H965 - H971. [Abstract] [Full Text] [PDF]

				B. Ramlawi, J. Feng, S. Mieno, C. Szabo, Z. Zsengeller, R. Clements, N. Sodha, M. Boodhwani, C. Bianchi, and F. W. Sellke Indices of Apoptosis Activation After Blood Cardioplegia and Cardiopulmonary Bypass Circulation, July 4, 2006; 114(1_suppl): I-257 - I-263. [Abstract] [Full Text] [PDF]

				A. Toth, J. R. Jeffers, P. Nickson, J.-Y. Min, J. P. Morgan, G. P. Zambetti, and P. Erhardt Targeted deletion of Puma attenuates cardiomyocyte death and improves cardiac function during ischemia-reperfusion Am J Physiol Heart Circ Physiol, July 1, 2006; 291(1): H52 - H60. [Abstract] [Full Text] [PDF]

				Y. Li, Y.-H. Song, J. Mohler, and P. Delafontaine ANG II induces apoptosis of human vascular smooth muscle via extrinsic pathway involving inhibition of Akt phosphorylation and increased FasL expression Am J Physiol Heart Circ Physiol, May 1, 2006; 290(5): H2116 - H2123. [Abstract] [Full Text] [PDF]

				S. Bae and L. Zhang Gender Differences in Cardioprotection against Ischemia/Reperfusion Injury in Adult Rat Hearts: Focus on Akt and Protein Kinase C Signaling J. Pharmacol. Exp. Ther., December 1, 2005; 315(3): 1125 - 1135. [Abstract] [Full Text] [PDF]

				A. M. Samarel Costameres, focal adhesions, and cardiomyocyte mechanotransduction Am J Physiol Heart Circ Physiol, December 1, 2005; 289(6): H2291 - H2301. [Abstract] [Full Text] [PDF]

				A. Malhotra, R. Begley, B. P. S. Kang, I. Rana, J. Liu, G. Yang, D. Mochly-Rosen, and L. G. Meggs PKC-{varepsilon}-dependent survival signals in diabetic hearts Am J Physiol Heart Circ Physiol, October 1, 2005; 289(4): H1343 - H1350. [Abstract] [Full Text] [PDF]

				R. Sheppard, M. Bedi, T. Kubota, M. J. Semigran, W. Dec, R. Holubkov, A. M. Feldman, W. D. Rosenblum, C. F. McTiernan, D. M. McNamara, et al. Myocardial Expression of Fas and Recovery of Left Ventricular Function in Patients With Recent-Onset Cardiomyopathy J. Am. Coll. Cardiol., September 20, 2005; 46(6): 1036 - 1042. [Abstract] [Full Text] [PDF]

				M. Masaki, M. Izumi, Y. Oshima, Y. Nakaoka, T. Kuroda, R. Kimura, S. Sugiyama, K. Terai, M. Kitakaze, K. Yamauchi-Takihara, et al. Smad1 Protects Cardiomyocytes From Ischemia-Reperfusion Injury Circulation, May 31, 2005; 111(21): 2752 - 2759. [Abstract] [Full Text] [PDF]

				S. Bae, R. D. Gilbert, C. A. Ducsay, and L. Zhang Prenatal cocaine exposure increases heart susceptibility to ischaemia-reperfusion injury in adult male but not female rats J. Physiol., May 15, 2005; 565(1): 149 - 158. [Abstract] [Full Text] [PDF]

				E. Camors, V. Monceau, and D. Charlemagne Annexins and Ca2+ handling in the heart Cardiovasc Res, March 1, 2005; 65(4): 793 - 802. [Abstract] [Full Text] [PDF]

				T. Schachner, A. Oberhuber, Y. Zou, A. Tzankov, H. Ott, G. Laufer, and J. Bonatti Rapamycin treatment is associated with an increased apoptosis rate in experimental vein grafts Eur. J. Cardiothorac. Surg., February 1, 2005; 27(2): 302 - 306. [Abstract] [Full Text] [PDF]

				L. Zhang Prenatal Hypoxia and Cardiac Programming Reproductive Sciences, January 1, 2005; 12(1): 2 - 13. [Abstract] [PDF]

				Y. Takada, M. Hashimoto, J. Kasahara, K. Aihara, and K. Fukunaga Cytoprotective Effect of Sodium Orthovanadate on Ischemia/Reperfusion-Induced Injury in the Rat Heart Involves Akt Activation and Inhibition of Fodrin Breakdown and Apoptosis J. Pharmacol. Exp. Ther., December 1, 2004; 311(3): 1249 - 1255. [Abstract] [Full Text] [PDF]

				S. Ghosh, D. Qi, D. An, T. Pulinilkunnil, A. Abrahani, K.-H. Kuo, R. B. Wambolt, M. Allard, S. M. Innis, and B. Rodrigues Brief episode of STZ-induced hyperglycemia produces cardiac abnormalities in rats fed a diet rich in n-6 PUFA Am J Physiol Heart Circ Physiol, December 1, 2004; 287(6): H2518 - H2527. [Abstract] [Full Text] [PDF]

				V. Monceau, Y. Belikova, G. Kratassiouk, D. Charue, E. Camors, C. Communal, P. Trouve, F. Russo-Marie, and D. Charlemagne Externalization of endogenous annexin A5 participates in apoptosis of rat cardiomyocytes Cardiovasc Res, December 1, 2004; 64(3): 496 - 506. [Abstract] [Full Text] [PDF]

				T. Urbanek, B. Skop, K. Ziaja, T. Wilczok, R. Wiaderkiewicz, A. Pal/asz, U. Mazurek, and E. Wielgus Sapheno-Femoral Junction Pathology: Molecular Mechanism of Saphenous Vein Incompetence Clinical and Applied Thrombosis/Hemostasis, October 1, 2004; 10(4): 311 - 321. [Abstract] [PDF]

				G. W. Moe, J. Marin-Garcia, A. Konig, M. Goldenthal, X. Lu, and Q. Feng In vivo TNF-{alpha} inhibition ameliorates cardiac mitochondrial dysfunction, oxidative stress, and apoptosis in experimental heart failure Am J Physiol Heart Circ Physiol, October 1, 2004; 287(4): H1813 - H1820. [Abstract] [Full Text] [PDF]

				T. M. Scarabelli, E. Pasini, G. Ferrari, M. Ferrari, A. Stephanou, K. Lawrence, P. Townsend, C. Chen-Scarabelli, G. Gitti, L. Saravolatz, et al. Warm blood cardioplegic arrest induces mitochondrial-mediated cardiomyocyte apoptosis associated with increased urocortin expression in viable cells J. Thorac. Cardiovasc. Surg., September 1, 2004; 128(3): 364 - 371. [Abstract] [Full Text] [PDF]

				E. E. Brevnova, O. Platoshyn, S. Zhang, and J. X.-J. Yuan Overexpression of human KCNA5 increases IK(V) and enhances apoptosis Am J Physiol Cell Physiol, September 1, 2004; 287(3): C715 - C722. [Abstract] [Full Text] [PDF]

				Z. Y. Fang, J. B. Prins, and T. H. Marwick Diabetic Cardiomyopathy: Evidence, Mechanisms, and Therapeutic Implications Endocr. Rev., August 1, 2004; 25(4): 543 - 567. [Abstract] [Full Text] [PDF]

				U. M. Fischer, P. Tossios, A. Huebner, H. J. Geissler, W. Bloch, and U. Mehlhorn Myocardial apoptosis prevention by radical scavenging in patients undergoing cardiac surgery J. Thorac. Cardiovasc. Surg., July 1, 2004; 128(1): 103 - 108. [Abstract] [Full Text] [PDF]

				T. Uchiyama, R. M. Engelman, N. Maulik, and D. K. Das Role of Akt Signaling in Mitochondrial Survival Pathway Triggered by Hypoxic Preconditioning Circulation, June 22, 2004; 109(24): 3042 - 3049. [Abstract] [Full Text] [PDF]

				S.R. Underwood, J. J Bax, J. v. Dahl, M. Y Henein, A. C van Rossum, E. R Schwarz, J.-L. Vanoverschelde, E. E.v. d. Wall, and W. Wijns Imaging techniques for the assessment of myocardial hibernation: Report of a Study Group of the European Society of Cardiology Eur. Heart J., May 2, 2004; 25(10): 815 - 836. [Abstract] [Full Text] [PDF]

				G. Li, S. Bae, and L. Zhang Effect of prenatal hypoxia on heat stress-mediated cardioprotection in adult rat heart Am J Physiol Heart Circ Physiol, May 1, 2004; 286(5): H1712 - H1719. [Abstract] [Full Text] [PDF]

				J. D. McCully, H. Wakiyama, Y.-J. Hsieh, M. Jones, and S. Levitsky Differential contribution of necrosis and apoptosis in myocardial ischemia-reperfusion injury Am J Physiol Heart Circ Physiol, May 1, 2004; 286(5): H1923 - H1935. [Abstract] [Full Text] [PDF]

				I. Shiraishi, J. Melendez, Y. Ahn, M. Skavdahl, E. Murphy, S. Welch, E. Schaefer, K. Walsh, A. Rosenzweig, D. Torella, et al. Nuclear Targeting of Akt Enhances Kinase Activity and Survival of Cardiomyocytes Circ. Res., April 16, 2004; 94(7): 884 - 891. [Abstract] [Full Text] [PDF]

				E. A. Woodcock Unc-II and Unc-III Are Cardioprotective against Ischemia Reperfusion Injury: An Essential Endogenous Cardioprotective Role for CRFR2 in the Murine Heart Endocrinology, January 1, 2004; 145(1): 21 - 23. [Full Text] [PDF]

				O. Yamaguchi, Y. Higuchi, S. Hirotani, K. Kashiwase, H. Nakayama, S. Hikoso, T. Takeda, T. Watanabe, M. Asahi, M. Taniike, et al. Targeted deletion of apoptosis signal-regulating kinase 1 attenuates left ventricular remodeling PNAS, December 23, 2003; 100(26): 15883 - 15888. [Abstract] [Full Text] [PDF]

				B. P. S. Kang, A. Urbonas, A. Baddoo, S. Baskin, A. Malhotra, and L. G. Meggs IGF-1 inhibits the mitochondrial apoptosis program in mesangial cells exposed to high glucose Am J Physiol Renal Physiol, November 1, 2003; 285(5): F1013 - F1024. [Abstract] [Full Text] [PDF]

				S. Zhang, I. Fantozzi, D. D. Tigno, E. S. Yi, O. Platoshyn, P. A. Thistlethwaite, J. M. Kriett, G. Yung, L. J. Rubin, and J. X.-J. Yuan Bone morphogenetic proteins induce apoptosis in human pulmonary vascular smooth muscle cells Am J Physiol Lung Cell Mol Physiol, September 1, 2003; 285(3): L740 - L754. [Abstract] [Full Text] [PDF]

				A. Gonzalez, M. A Fortuno, R. Querejeta, S. Ravassa, B. Lopez, N. Lopez, and J. Diez Cardiomyocyte apoptosis in hypertensive cardiomyopathy Cardiovasc Res, September 1, 2003; 59(3): 549 - 562. [Abstract] [Full Text] [PDF]

				S. Bae, Y. Xiao, G. Li, C. A. Casiano, and L. Zhang Effect of maternal chronic hypoxic exposure during gestation on apoptosis in fetal rat heart Am J Physiol Heart Circ Physiol, August 7, 2003; 285(3): H983 - H990. [Abstract] [Full Text] [PDF]

				G. Li, Y. Xiao, J. L. Estrella, C. A. Ducsay, R. D. Gilbert, and L. Zhang Effect of Fetal Hypoxia on Heart Susceptibility to Ischemia and Reperfusion Injury in the Adult Rat Reproductive Sciences, July 1, 2003; 10(5): 265 - 274. [Abstract] [PDF]

				U. M. Fischer, O. Klass, U. Stock, J. Easo, H. J. Geissler, J. H. Fischer, W. Bloch, and U. Mehlhorn Cardioplegic arrest induces apoptosis signal-pathway in myocardial endothelial cells and cardiac myocytes Eur. J. Cardiothorac. Surg., June 1, 2003; 23(6): 984 - 990. [Abstract] [Full Text] [PDF]

				S. Chatterjee, L. T. Bish, V. Jayasankar, A. S. Stewart, Y. J. Woo, M. T. Crow, T. J. Gardner, and H. L. Sweeney Blocking the development of postischemic cardiomyopathy with viral gene transfer of the apoptosis repressor with caspase recruitment domain J. Thorac. Cardiovasc. Surg., June 1, 2003; 125(6): 1461 - 1469. [Abstract] [Full Text] [PDF]

				D. Ekhterae, O. Platoshyn, S. Zhang, C. V. Remillard, and J. X.-J. Yuan Apoptosis repressor with caspase domain inhibits cardiomyocyte apoptosis by reducing K+ currents Am J Physiol Cell Physiol, June 1, 2003; 284(6): C1405 - C1410. [Abstract] [Full Text] [PDF]

				J. Goldman, L. Zhong, and S. Q. Liu Degradation of alpha -actin filaments in venous smooth muscle cells in response to mechanical stretch Am J Physiol Heart Circ Physiol, May 1, 2003; 284(5): H1839 - H1847. [Abstract] [Full Text] [PDF]

				Y. Ogata, M. Takahashi, S. Ueno, K. Takeuchi, T. Okada, H. Mano, S. Ookawara, K. Ozawa, B. C. Berk, U. Ikeda, et al. Antiapoptotic Effect of Endothelin-1 in Rat Cardiomyocytes In Vitro Hypertension, May 1, 2003; 41(5): 1156 - 1163. [Abstract] [Full Text] [PDF]

				E.-L. Marchand, S. Der Sarkissian, P. Hamet, and D. deBlois Caspase-Dependent Cell Death Mediates the Early Phase of Aortic Hypertrophy Regression in Losartan-Treated Spontaneously Hypertensive Rats Circ. Res., April 18, 2003; 92(7): 777 - 784. [Abstract] [Full Text] [PDF]

				E. J. Su, C. L. Cioffi, S. Stefansson, N. Mittereder, M. Garay, D. Hreniuk, and G. Liau Gene therapy vector-mediated expression of insulin-like growth factors protects cardiomyocytes from apoptosis and enhances neovascularization Am J Physiol Heart Circ Physiol, April 1, 2003; 284(4): H1429 - H1440. [Abstract] [Full Text] [PDF]

				B. P. S. Kang, S. Frencher, V. Reddy, A. Kessler, A. Malhotra, and L. G. Meggs High glucose promotes mesangial cell apoptosis by oxidant-dependent mechanism Am J Physiol Renal Physiol, March 1, 2003; 284(3): F455 - F466. [Abstract] [Full Text] [PDF]

				S. Der Sarkissian, E.-L. Marchand, D. Duguay, P. Hamet, and D. deBlois Reversal of interstitial fibroblast hyperplasia via apoptosis in hypertensive rat heart with valsartan or enalapril Cardiovasc Res, March 1, 2003; 57(3): 775 - 783. [Abstract] [Full Text] [PDF]

				B. Nadal-Ginard, J. Kajstura, A. Leri, and P. Anversa Myocyte Death, Growth, and Regeneration in Cardiac Hypertrophy and Failure Circ. Res., February 7, 2003; 92(2): 139 - 150. [Abstract] [Full Text] [PDF]

				R. M. Mentzer Jr., M. S. Jahania, and R. D. Lasley Myocardial Protection Card. Surg. Adult, January 1, 2003; 2(2003): 413 - 438. [Full Text]

				T. L. Vanden Hoek, Y. Qin, K. Wojcik, C.-Q. Li, Z.-H. Shao, T. Anderson, L. B. Becker, and K. J. Hamann Reperfusion, not simulated ischemia, initiates intrinsic apoptosis injury in chick cardiomyocytes Am J Physiol Heart Circ Physiol, January 1, 2003; 284(1): H141 - H150. [Abstract] [Full Text] [PDF]

				P. Liu, B. Xu, T. A Cavalieri, and C. E Hock Age-related difference in myocardial function and inflammation in a rat model of myocardial ischemia-reperfusion Cardiovasc Res, December 1, 2002; 56(3): 443 - 453. [Abstract] [Full Text] [PDF]

				O. Platoshyn, S. Zhang, S. S. McDaniel, and J. X.-J. Yuan Cytochrome c activates K+ channels before inducing apoptosis Am J Physiol Cell Physiol, October 1, 2002; 283(4): C1298 - C1305. [Abstract] [Full Text] [PDF]

				J. Bartunek, M. Vanderheyden, M. W. M. Knaapen, W. Tack, M. M. Kockx, and M. Goethals Deoxyribonucleic acid damage/repairproteins are elevated in the failing human myocardium due to idiopathic dilated cardiomyopathy J. Am. Coll. Cardiol., September 18, 2002; 40(6): 1097 - 1103. [Abstract] [Full Text] [PDF]

				A. Moretti, H.-J. Weig, T. Ott, M. Seyfarth, H.-P. Holthoff, D. Grewe, A. Gillitzer, L. Bott-Flugel, A. Schomig, M. Ungerer, et al. Essential myosin light chain as a target for caspase-3 in failing myocardium PNAS, September 3, 2002; 99(18): 11860 - 11865. [Abstract] [Full Text] [PDF]

				M. Akao, Y. Teshima, and E. Marban Antiapoptotic effect of nicorandil mediated by mitochondrial atp-sensitive potassium channels in cultured cardiac myocytes J. Am. Coll. Cardiol., August 21, 2002; 40(4): 803 - 810. [Abstract] [Full Text] [PDF]

				Z.-Q. Zhao and J. Vinten-Johansen Myocardial apoptosis and ischemic preconditioning Cardiovasc Res, August 15, 2002; 55(3): 438 - 455. [Abstract] [Full Text] [PDF]

				H. Sakuma, M. Yamamoto, M. Okumura, T. Kojima, T. Maruyama, and K. Yasuda High glucose inhibits apoptosis in human coronary artery smooth muscle cells by increasing bcl-xL and bfl-1/A1 Am J Physiol Cell Physiol, August 1, 2002; 283(2): C422 - C428. [Abstract] [Full Text] [PDF]

				T. Date, A. J Belanger, S. Mochizuki, J. A Sullivan, L. X Liu, A. Scaria, S. H Cheng, R. J Gregory, and C. Jiang Adenovirus-mediated expression of p35 prevents hypoxia/reoxygenation injury by reducing reactive oxygen species and caspase activity Cardiovasc Res, August 1, 2002; 55(2): 309 - 319. [Abstract] [Full Text] [PDF]

				H. Toko, W. Zhu, E. Takimoto, I. Shiojima, Y. Hiroi, Y. Zou, T. Oka, H. Akazawa, M. Mizukami, M. Sakamoto, et al. Csx/Nkx2-5 Is Required for Homeostasis and Survival of Cardiac Myocytes in the Adult Heart J. Biol. Chem., June 28, 2002; 277(27): 24735 - 24743. [Abstract] [Full Text] [PDF]

				G. Yaniv, M. Shilkrut, R. Lotan, G. Berke, S. Larisch, and O. Binah Hypoxia predisposes neonatal rat ventricular myocytes to apoptosis induced by activation of the Fas (CD95/Apo-1) receptor: Fas activation and apoptosis in hypoxic myocytes Cardiovasc Res, June 1, 2002; 54(3): 611 - 623. [Abstract] [Full Text] [PDF]

				S. Kotamraju, C. R. Chitambar, S. V. Kalivendi, J. Joseph, and B. Kalyanaraman Transferrin Receptor-dependent Iron Uptake Is Responsible for Doxorubicin-mediated Apoptosis in Endothelial Cells. ROLE OF OXIDANT-INDUCED IRON SIGNALING IN APOPTOSIS J. Biol. Chem., May 3, 2002; 277(19): 17179 - 17187. [Abstract] [Full Text] [PDF]

				H. Jankala, C. J. P. Eriksson, K. K. Eklund, M. Harkonen, and T. Maki COMBINED CALCIUM CARBIMIDE AND ETHANOL TREATMENT INDUCES HIGH BLOOD ACETALDEHYDE LEVELS, MYOCARDIAL APOPTOSIS AND ALTERED EXPRESSION OF APOPTOSIS-REGULATING GENES IN RAT Alcohol Alcohol., May 1, 2002; 37(3): 222 - 228. [Abstract] [Full Text] [PDF]

				Q. Zhang, X. Zeng, J. Guo, and X. Wang Oxidant stress mechanism of homocysteine potentiating Con A-induced proliferation in murine splenic T lymphocytes Cardiovasc Res, March 1, 2002; 53(4): 1035 - 1042. [Abstract] [Full Text] [PDF]

				H. FAUVEL, P. MARCHETTI, G. OBERT, O. JOULAIN, C. CHOPIN, P. FORMSTECHER, and R. NEVIERE Protective Effects of Cyclosporin A from Endotoxin-induced Myocardial Dysfunction and Apoptosis in Rats Am. J. Respir. Crit. Care Med., February 15, 2002; 165(4): 449 - 455. [Abstract] [Full Text] [PDF]

				S. Krick, O. Platoshyn, M. Sweeney, S. S. McDaniel, S. Zhang, L. J. Rubin, and J. X.-J. Yuan Nitric oxide induces apoptosis by activating K+ channels in pulmonary vascular smooth muscle cells Am J Physiol Heart Circ Physiol, January 1, 2002; 282(1): H184 - H193. [Abstract] [Full Text] [PDF]

				J.-L. Bascands, J.-P. Girolami, M. Troly, I. Escargueil-Blanc, D. Nazzal, R. Salvayre, and N. Blaes Angiotensin II Induces Phenotype-Dependent Apoptosis in Vascular Smooth Muscle Cells Hypertension, December 1, 2001; 38(6): 1294 - 1299. [Abstract] [Full Text] [PDF]

				Z. Mallat, P. Fornes, R. Costagliola, B. Esposito, J. Belmin, D. Lecomte, and A. Tedgui Age and Gender Effects on Cardiomyocyte Apoptosis in the Normal Human Heart J. Gerontol. A Biol. Sci. Med. Sci., November 1, 2001; 56(11): M719 - 723. [Abstract] [Full Text] [PDF]

				F. B. Mehrhof, F. U. Muller, M. W. Bergmann, P. Li, Y. Wang, W. Schmitz, R. Dietz, and R. von Harsdorf In Cardiomyocyte Hypoxia, Insulin-Like Growth Factor-I-Induced Antiapoptotic Signaling Requires Phosphatidylinositol-3-OH-Kinase-Dependent and Mitogen-Activated Protein Kinase-Dependent Activation of the Transcription Factor cAMP Response Element-Binding Protein Circulation, October 23, 2001; 104(17): 2088 - 2094. [Abstract] [Full Text] [PDF]

				G. S. Filippatos, N. Gangopadhyay, O. Lalude, N. Parameswaran, S. I. Said, W. Spielman, and B. D. Uhal Regulation of apoptosis by vasoactive peptides Am J Physiol Lung Cell Mol Physiol, October 1, 2001; 281(4): L749 - L761. [Abstract] [Full Text] [PDF]

				S. Krick, O. Platoshyn, S. S. McDaniel, L. J. Rubin, and J. X.-J. Yuan Augmented K+ currents and mitochondrial membrane depolarization in pulmonary artery myocyte apoptosis Am J Physiol Lung Cell Mol Physiol, October 1, 2001; 281(4): L887 - L894. [Abstract] [Full Text] [PDF]

				J. Grunenfelder, D. N. Miniati, S. Murata, V. Falk, E. G. Hoyt, M. Kown, M. L. Koransky, and R. C. Robbins Upregulation of Bcl-2 Through Caspase-3 Inhibition Ameliorates Ischemia/Reperfusion Injury in Rat Cardiac Allografts Circulation, September 18, 2001; 104 (2009): I-202 - I-206. [Abstract] [Full Text] [PDF]

				R. S. Hundal, B. S. Salh, J. W. Schrader, A. Gomez-Munoz, V. Duronio, and U. P. Steinbrecher Oxidized low density lipoprotein inhibits macrophage apoptosis through activation of the PI 3-kinase/PKB pathway J. Lipid Res., September 1, 2001; 42(9): 1483 - 1491. [Abstract] [Full Text] [PDF]

				F. Qin, N. K. Rounds, W. Mao, K. Kawai, and C.-s. Liang Antioxidant vitamins prevent cardiomyocyte apoptosis produced by norepinephrine infusion in ferrets Cardiovasc Res, September 1, 2001; 51(4): 736 - 748. [Abstract] [Full Text] [PDF]

				B. Stadler, J. Phillips, Y. Toyoda, M. Federman, S. Levitsky, and J. D. McCully Adenosine-enhanced ischemic preconditioning modulates necrosis and apoptosis: effects of stunning and ischemia-reperfusion Ann. Thorac. Surg., August 1, 2001; 72(2): 555 - 563. [Abstract] [Full Text] [PDF]

				D. Ekhterae, O. Platoshyn, S. Krick, Y. Yu, S. S. McDaniel, and J. X.-J. Yuan Bcl-2 decreases voltage-gated K+ channel activity and enhances survival in vascular smooth muscle cells Am J Physiol Cell Physiol, July 1, 2001; 281(1): C157 - C165. [Abstract] [Full Text] [PDF]

				H. Sugino, R. Ozono, S. Kurisu, H. Matsuura, M. Ishida, T. Oshima, M. Kambe, Y. Teranishi, H. Masaki, and H. Matsubara Apoptosis Is Not Increased in Myocardium Overexpressing Type 2 Angiotensin II Receptor in Transgenic Mice Hypertension, June 1, 2001; 37(6): 1394 - 1398. [Abstract] [Full Text] [PDF]

				H. Fauvel, P. Marchetti, C. Chopin, P. Formstecher, and R. Neviere Differential effects of caspase inhibitors on endotoxin-induced myocardial dysfunction and heart apoptosis Am J Physiol Heart Circ Physiol, April 1, 2001; 280(4): H1608 - H1614. [Abstract] [Full Text] [PDF]

				A. Chesley, M. S. Lundberg, T. Asai, R.-P. Xiao, S. Ohtani, E. G. Lakatta, and M. T. Crow The {beta}2-Adrenergic Receptor Delivers an Antiapoptotic Signal to Cardiac Myocytes Through Gi-Dependent Coupling to Phosphatidylinositol 3'-Kinase Circ. Res., December 8, 2000; 87(12): 1172 - 1179. [Abstract] [Full Text] [PDF]

				K. Fuse, M. Kodama, Y. Okura, M. Ito, S. Hirono, K. Kato, H. Hanawa, and Y. Aizawa Predictors of Disease Course in Patients With Acute Myocarditis Circulation, December 5, 2000; 102(23): 2829 - 2835. [Abstract] [Full Text] [PDF]

				J. He, Y. Xiao, C. A. Casiano, and L. Zhang Role of Mitochondrial Cytochrome c in Cocaine-Induced Apoptosis in Coronary Artery Endothelial Cells J. Pharmacol. Exp. Ther., December 1, 2000; 295(3): 896 - 903. [Abstract] [Full Text]

				T. E. McDonald, M. N. Grinman, C. M. Carthy, and K. R. Walley Endotoxin infusion in rats induces apoptotic and survival pathways in hearts Am J Physiol Heart Circ Physiol, November 1, 2000; 279(5): H2053 - H2061. [Abstract] [Full Text] [PDF]

				M. Thibonnier, D. M. Conarty, and C. L. Plesnicher Mediators of the mitogenic action of human V1 vascular vasopressin receptors Am J Physiol Heart Circ Physiol, November 1, 2000; 279(5): H2529 - H2539. [Abstract] [Full Text] [PDF]

				Q. N. Diep, R. M. Touyz, and E. L. Schiffrin Docosahexaenoic Acid, a Peroxisome Proliferator-Activated Receptor-{alpha} Ligand, Induces Apoptosis in Vascular Smooth Muscle Cells by Stimulation of p38 Mitogen-Activated Protein Kinase Hypertension, November 1, 2000; 36(5): 851 - 855. [Abstract] [Full Text] [PDF]

				I. Jeremias, C. Kupatt, A. Martin-Villalba, H. Habazettl, J. Schenkel, P. Boekstegers, and K. M. Debatin Involvement of CD95/Apo1/Fas in Cell Death After Myocardial Ischemia Circulation, August 22, 2000; 102(8): 915 - 920. [Abstract] [Full Text] [PDF]

				P. M. Kang, A. Haunstetter, H. Aoki, A. Usheva, and S. Izumo Morphological and Molecular Characterization of Adult Cardiomyocyte Apoptosis During Hypoxia and Reoxygenation Circ. Res., July 21, 2000; 87(2): 118 - 125. [Abstract] [Full Text] [PDF]

				Q. Xu, G. Schett, H. Perschinka, M. Mayr, G. Egger, F. Oberhollenzer, J. Willeit, S. Kiechl, and G. Wick Serum Soluble Heat Shock Protein 60 Is Elevated in Subjects With Atherosclerosis in a General Population Circulation, July 4, 2000; 102(1): 14 - 20. [Abstract] [Full Text] [PDF]

				B. Ding, R. L. Price, E. C. Goldsmith, T. K. Borg, X. Yan, P. S. Douglas, E. O. Weinberg, J. Bartunek, T. Thielen, V. V. Didenko, et al. Left Ventricular Hypertrophy in Ascending Aortic Stenosis Mice : Anoikis and the Progression to Early Failure Circulation, June 20, 2000; 101(24): 2854 - 2862. [Abstract] [Full Text] [PDF]

This Article Extract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Haunstetter, A. Articles by Izumo, S. Search for Related Content PubMed PubMed Citation Articles by Haunstetter, A. Articles by Izumo, S.