Review

Stress (Heat Shock) Proteins

Molecular Chaperones in Cardiovascular Biology and Disease

Ivor J. Benjamin, D. Randy McMillan
https://doi.org/10.1161/01.RES.83.2.117
Circulation Research. 1998;83:117-132
Originally published July 27, 1998

Jump to

Abstract

Abstract—How a cell responds to stress is a central problem in cardiovascular biology. Diverse physiological stresses (eg, heat, hemodynamics, mutant proteins, and oxidative injury) produce multiple changes in a cell that ultimately affect protein structures and function. Cells from different phyla initiate a cascade of events that engage essential proteins, the molecular chaperones, in decisions to repair or degrade damaged proteins as a defense strategy to ensure survival. Accumulative evidence indicates that molecular chaperones such as the heat shock family of stress proteins (HSPs) actively participate in an array of cellular processes, including cytoprotection. The versatility of the ubiquitous HSP family is further enhanced by stress-inducible regulatory networks, both at the transcriptional and posttranscriptional levels. In the present review, we discuss the regulation and function of HSP chaperones and their clinical significance in conditions such as cardiac hypertrophy, vascular wall injury, cardiac surgery, ischemic preconditioning, aging, and, conceivably, mutations in genes encoding contractile proteins and ion channels.

Physiological stresses ranging from myocardial ischemia to genetic mutations produce disease states in which protein damage and misfolded protein structures are a common denominator.1 2 3 4 5 6 7 8 9 How does the cell respond? Multiple endogenous pathways are engaged in restoring cellular homeostasis, but one well-characterized mechanism that involves protein folding is the heat shock family of stress proteins, or HSPs.10 11 Insight into the mechanisms underlying HSP function is provided by 2 main lines of evidence: (1) the correct folding of many proteins in a cell requires protein-folding machinery, the molecular chaperones,12 13 and (2) HSP chaperones repair denatured proteins or promote their degradation after heat shock.14 15

Genetic studies provide convincing proof in different phyla that overexpression of stress proteins is a powerful means of cytoprotection, even in the intact heart.10 16 17 18 Similarly, biochemical studies have demonstrated that the Hsc70 chaperone increases the productive folding of the common ΔF508 mutation of CFTR. This suggests a physiological role of an HSP chaperone in human diseases.19 20 Divergent mechanisms that produce abnormal or misfolded cellular proteins converge into a common pathway, leading to an increase in the levels of cytoprotective stress proteins, which decrease or neutralize the deleterious effects of acute or chronic stresses.

In this review, we summarize present knowledge about the regulation and function of individual chaperones (eg, Hsp90, Hsp70, Hsp60, Hsp47, Hsp27, and αB-crystallin) in the cardiovascular system. Besides their well-established roles in cell survival (necrosis and apoptosis), we will emphasize the emerging evidence regarding chaperone functions in physiological adaptation during cardiac hypertrophy, ischemic preconditioning, vessel wall injury, oxidative stress, and aging. Although we presently can only speculate about their roles in specific cardiac diseases, we will discuss many potential opportunities to establish whether HSP chaperones either exert an effect on or play a direct physiological role in the natural history of diseases resulting from mutations of cardiac contractile apparatus (eg, hypertrophic cardiomyopathy) and ion channels (eg, long-QT syndrome) in humans.

Definitions and Nomenclature

What Are Stress “Heat Shock” Proteins?

The term “heat shock” protein is a misnomer but remains as a legacy of Ritossa’s serendipitous discovery21 that heat shock produced chromosomal puffs of salivary gland cells in Drosophila. Heat stress (≈5° above normal growth temperature) upregulates the rapid synthesis of a multigene family of proteins, originally called heat shock proteins,22 which are the result of a response often referred to as the heat shock response.10 21 Prior sublethal heat stress transiently increases the ability of a cell to withstand an otherwise lethal subsequent heat challenge. This phenomenon, or thermotolerance, played a key role in launching numerous studies in both in vitro and in vivo experimental models in which a similar association was found between the heat shock response and protection against either simulated hypoxia or ischemia. Indeed, diverse stresses, including heavy metals, amino acid analogues, inflammation, and oxidative/ischemic stress, induce the expression of HSP genes. Consequently, the terms “stress proteins” or “heat shock family of stress proteins” are preferred, although many of these proteins have essential functions during unstressed conditions.13

Stress proteins belong to multigene families that range in molecular size from 10 to 150 kDa and are found in all major cellular compartments. The convention is to name stress proteins of various molecular sizes as follows: Hsp27, Hsp70, and Hsp90; whereas heat shock protein genes are designated as follows: hsp27, hsp70, and hsp90.23 The distinction between constitutively expressed (eg, Hsc70 and Hsp90β) or cognate members of the HSP family and their inducible isoforms (Hsp70 and Hsp90α, respectively) is arbitrary, since accumulating evidence, in physiologically relevant in vivo systems, now indicates that such relationships depend on cell- and tissue-restricted expression.

Cellular Consequences of Heat and Ischemic Stress Are Similar

Like experimental ischemia/reperfusion, heat shock is a stress that disrupts numerous metabolic processes and cellular structures and that culminates in cell death when a critical threshold is exceeded.10 24 25 Both heat stress and ischemia cause extensive damage to the cytoskeleton, including collapse of the threadlike intermediate filament network into large perinuclear aggregates, reorganization of the cytoplasmic network, relocalizaton of actin-containing fibers around the nucleus, and disruption of microtubules and the mitotic spindle.26 27 Mitochondrial swelling, loss of mitochondria, and uncoupling of oxidative phosphorylation are similarly shared features of heat shock and early reversible ischemic injury.28 29 30

Characteristically, general protein synthesis is inhibited after extreme heat challenge as a result of phosphorylation of initiation factors such as eIF2α, which disrupts ribosomal assembly and inactivates cap-binding proteins.31 32 33 In contrast, HSP genes are efficiently expressed after heat challenge, in part, as a result of the absence of introns in several inducible (eg, hsp70) genes. In addition, alterations of mRNA splicing and heat-induced stabilization of mRNA are adaptive mechanisms used to efficiently translate stress proteins, which can reach 15% to 25% of total intracellular protein within minutes after physiological stress under these conditions.10 34 Coincidentally, several cytosolic chaperones translocate into the nucleus,35 where heat-induced inhibition of DNA chromatin assembly exposes a nuclease-sensitive conformation, a pathognomonic feature of both heat- and ischemia-induced apoptosis.36 Less dramatic changes are seen in integral membrane proteins, the lipid bilayer, and cellular surface morphology. Cessation of noxious stimuli is followed by rapid and efficient degradation of Hsp mRNAs.37 38 39

As mentioned previously, prior sublethal heat stress or “hyperthermic preconditioning” profoundly attenuates all of the heat-induced cellular changes to a subsequent severe heat challenge. Moreover, pretreatment with heat produces “cross tolerance” to varying types of physiological stress. For example, protection of the intact ischemic heart after heat pretreatment may last for hours to days.40 41 Insight gained from the physiological roles of Hsp expression during the heat shock response has contributed to current thoughts about chaperone functions in pathological states likely to result in abnormal protein folding.

Attention has primarily focused on the induction of HSP chaperones and the potential repair mechanisms involved in mitigating ischemia/reperfusion injury. Figure 1⇓ schematically summarizes many of these concepts and illustrates the multiple well-recognized mechanisms implicated in ischemic myocardial injury, including oxidative stress/damage, calcium overload and activated proteases, release of proteolytic and lysosomal enzymes, alterations of the cytoskeleton, and complement activation.

Figure 1.
Figure 1.

A summary of the major pathophysiological signals that activate HSP synthesis (left of vertical solid line) and the potential functions of HSPs (right of vertical solid line). Cellular injury is manifested by increased generation of ROS, availability of redox-active iron, peroxidation of membrane lipids, and protein damage, among others.92 The extracellular sources of ROS (A) could be endothelial cells, VSMCs, and even myocytes in the surrounding tissue; mitochondrial electron transport of molecular oxygen (B) may be the main intracellular source for ROS generation. Intracellular free calcium (C), which increases 10-fold within 10 minutes of reperfusion,228 229 has been implicated in the activation of proteases (D), which, in turn, are thought to contribute to intracellular myocardial injury.230 231 232 Damage to the cytoskeleton (E) is an early event of ischemic injury, which causes ventricular dysfunction or “myocardial stunning” when the injury is reversible.87 Myocardial injury could also occur from recruitment of polymorphonuclear leukocytes (PMNs) by multiple mechanisms into the ischemic territory and by the release of oxygen-derived free radicals (A), cytotoxic lysosomal enzymes (F), extracellular proteases (G), and complement activation (H) (reviewed in Reference 233). Diverse physiological signals are thought to activate the stress-inducible HSF1 (I), which binds to the sequence-specific heat shock element (HSE) (J), contained in the promoters of all HSPs (K). Although the precise mechanism of Hsp70-mediated ischemic protection is poorly understood, it is widely attributed to the biological property of “molecular chaperones,” which are proposed to assist in the assembly or repair of newly synthesized or damaged proteins.11 234 235 In physiological terms, potential functions for molecular chaperones in the ischemic heart include the following: protein folding of newly synthesized polypeptides essential for maintaining oxidative metabolism after myocyte damage (L), protection of mitochondria from ROS and cytokines such as TNFα204 236 and translocation of newly synthesized proteins during organelle repair (M), repair of critical structural proteins after ischemia-induced cytoskeletal alterations (N),237 recycling of membrane vesicles (Hsc70) (O), transport of potential toxic byproducts for degradation by the proteasome (P),78 238 239 suppression of proinflammatory cytokines such as pro–interleukin-1β (Q),204 236 240 suppression of NADPH oxidase and the oxidative burst by the heat shock response (R),241 protection by NO production from inducible synthesis of HSP expression (S),61 242 243 244 245 246 prevention of apoptosis either through the mitochondrial chaperone Hsp60 binding of cytochrome c and/or Hsp70 binding of cytosolic targets (T),36 204 repair of ion channel (U), collagen synthesis by Hsp47 chaperone for reparative fibrosis (V),180 and modulation of the immune-mediated ischemic injury (W).241

Diverse Physiological Stresses Induce HSP Gene Expression Through a Common Mechanism

Rapid induction of stress protein expression is accomplished through mechanisms of transcriptional activation and preferential translation.10 42 HSFs (HSF1 through HSF4) regulate the inducible synthesis of HSPs during development, growth, and adaptation.42 43 44 Whereas essential single-copy genes encode HSF in Saccharomyces cerevisiae and Drosophila,45 46 multiple HSFs have been identified in chicks, plants, mice, and humans.47 48 49 50 51 Two HSFs (HSF1 and HSF2, encoding proteins of 75 and 72 kDa, respectively) have been identified in the mouse.49 Neither HSF1 nor HSF2 is heat inducible, but HSF1 is hyperphosphorylated in a ras-dependent manner by members of the MAPK subfamilies (ERK1, JNK/SAPK, and p38 protein kinase) during physiological stress.52 53 During unstressed conditions, both DNA-binding activity and transcriptional activity of vertebrate HSF1 are under tight negative control (reviewed in Reference 4444 ). However, it remains controversial whether repression by chaperone Hsp70, sequestration of constitutive phosphorylation on serine residues, or unknown inhibitory regulators are the principal mechanisms underlying stress-inducible activation and rapid deactivation of HSF1.43 54 55 56

Previous studies have demonstrated that in response to both heat and simulated ischemia, the mechanism(s) for HSF1 activation is similar, if not identical, in myogenic cells57 and that depletion of intracellular ATP plays an important role in triggering the HSF1-DNA binding activity.58 In disease conditions, inducers of HSF1 activation, such as oxidized LDL and reactive nitrogen intermediates, are thought to increase protein damage, which triggers upregulation of HSP gene expression.59 60 61 However, transcriptional activation of the HSF1 pathway does not require new protein synthesis, since the preexisting transactivator (HSF1) is inactive in the unstressed state.43 56 57 Physiological stresses, such as heat and ischemia, induce HSF1 monomers to oligomerize as homotrimers, which then bind to an upstream sequence-specific motif, heat shock element, in the promoter of all stress-inducible HSP genes62 63 (Figure 1I⇑ through 1K⇑). We recently established a gene knockout model of Hsf1 and demonstrated in in vitro studies the essential requirement of this regulatory pathway in cellular defense and thermotolerance.36 In addition, stress protein expression has been implicated in promoting tumor cell survival64 and protection of the ischemic heart.16 17 18

Stress Protein Overexpression Enhances the Speed of Physiological Recovery of the Ischemic Heart

A substantial literature describes the induction of Hsp70 by ischemia,57 65 66 the potential role of Hsp70 in ischemic preconditioning,40 67 and an inverse correlation between expression of Hsp70 induced by ischemic or thermal preconditioning and infarct size in animal models.41 68 69 70 In addition, forced expression of Hsp70 conveys a cytoprotective effect in cultured cells, including cardiac myocytes subjected to simulated ischemia.71 72 Specifically, overexpression of the major 70-kDa heat shock protein (Hsp70) in transgenic mice improves myocardial function,16 17 18 preserves metabolic functional recovery,18 and reduces infarct size73 after ischemia/reperfusion. In addition to Hsp70, Hsp27 and αB-crystallin can protect primary cardiomyocytes against ischemic damage.74 Although the precise mechanisms are insufficiently understood, stress proteins are thought to mediate cardioprotection through their biological functions as molecular chaperones.

Stress Proteins Can Function as Molecular Chaperones

Molecular chaperones, like Hsp70 and αB-crystallin, are proteins that facilitate the folding, assembly, and disassembly of other proteins but are not part of the finished product.75 Since many proteins require chaperones to fold, these proteins are essential components in the final stage of the central dogma of molecular biology: DNA↔RNA→polypeptide→folded protein.11 75 In vitro chaperones function to prevent aggregation of other proteins under conditions of stress and to promote restoration of enzymatic activity of denatured protein substrates or enzymes (eg, citrate synthase, β-galactosidase, or luciferase) on removal of the stress.11 13 76

Figure 2⇓ shows schematically the reaction cycle of chaperone Hsc70 in relation to recently identified cochaperones and molecular substrates in the cell. For example, chaperone Hsp40 plays a major catalytic function in loading target substrates onto the Hsc70 binding/release cycle.77 Although the mechanisms of these functions are still emerging, the major functions of molecular chaperones are to (1) transiently bind and delay the folding of nascent polypeptide chains until synthesis is complete, (2) maintain polypeptide chains in an appropriate conformation suitable for translocation across organelle membranes, (3) prevent aggregation from intramolecular or intermolecular interactions, (4) actively disassemble clathrin-coated vesicles, (5) hold steroid aporeceptor complexes in ligand competent states (Hsp90 and cochaperone), and (6) assist in degrading toxic metabolites by promoting ubiquination and proteasome lysis78 (Figure 1L⇑ through 1P⇑).

Figure 2.
Figure 2.

A proposed scheme for the reaction cycle of chaperone Hsc70 complex in folding of a hypothetical substrate in the cell. Starting at the bottom of the figure, chaperone Hsc70 (A) consists of an N-terminal ATPase and C-terminal domain for binding target substrate. Hsp40 (B), the eukaryotic homologue of DnaJ, either binds unfolded proteins (UPs) first (C) and then binds Hsc70.ADP, or it binds to the Hsc70.ADP.UP complex (D), which has a low on/off rate for UPs. Several different fates for the Hsc70.ADP.UP complex are envisioned, each of which depends on the replacement of Hsp40 by different accessory partners, specifically, Hip (Hsc70-interacting protein), Hop (Hsc70/Hsp90-organizing protein), and Hap (Hsc70 accessory protein).166 247 248 After Hsp40 is released, Hip binds to the ATPase domain of Hsc70 (E), stimulates its activity, and then remains bound to stabilize the ADP-Hsc70-substrate complex, suggesting that it may play a role in the transport of substrates within cells (F).166 Hop serves as a physical linker between Hsc70 and Hsp90 (G), presumably to facilitate the transfer of UPs between these chaperones. Whether or not Hop changes the ATPase activity of Hsc70 is controversial.249 The function of Hup, which stimulates the release of UPs from Hsc70 (H) and converts oligomers of Hsc70 into monomers (I), remains to be established. The energy transferred from ATP hydrolysis, the rate-limiting step of the eukaryotic chaperone cycle, is used in successive cycles to assist folding and prevent aggregation and degradation. To this end, two related proteins, BAG-1 (not shown) and Hap (J), which bind to the Hsc70 ATPase domain, also inhibit binding of Hsp70 to unfolded protein substrate in vitro, suggesting that these proteins may play roles in maintaining quality control by directing nonproductive interactions toward degradation250 (illustration kindly provided by L.E. Hightower, University of Connecticut, Storrs).

The Case for Molecular Chaperones in Cardiac Diseases

Widespread clinical interest into the biological functions of molecular chaperones extends over a range of human pathologies from degenerative conditions such as Alzheimer’s disease, prions, amyloidosis, cataract formation, sickle cell disease, cystic fibrosis, and various cardiac diseases including myocardial ischemia. Early events that reestablish timely reflow of the ischemic myocardium either through thrombolytics, direct angioplasty, or spontaneous clot lysis are essential for enhancing myocardial salvage and reducing morbidity and mortality.79 80 Nonetheless, recurrent ischemia either from rupture of an unstable plaque or congestive heart failure can complicate the clinical course of an acute myocardial infarction. In uncomplicated acute myocardial infarction, physiological recovery at the cellular level begins within minutes but could last for weeks to months before myocardial repair is complete. Thus, endogenous protective mechanisms have clinical relevance in mitigating the effects of ischemic heart disease.

Biochemical Activities of HSP Regulatory Pathway and Chaperones During Myocardial Ischemia

In previous work undertaken to define the proximate stimulus to HSF activation, we observed that severe intracellular acidosis (pH 6.7) was insufficient to induce the DNA binding of HSF1 in cultured myogenic cells exposed to simulated ischemia, if ATP stores were preserved.58 In contrast, severe ATP depletion (65%) stimulated DNA binding of HSF1, even if pH was maintained within the normal range.58 In the intact ischemic heart, 15 minutes of ischemia, which produces reversible injury, is associated with a similar reduction (65%) of high-energy ATP stores, whereas lethal injury is found with prolonged ischemia (>40 minutes) and >90% depletion of high-energy pools.81 The Km for the weak ATPase activity of bovine Hsc70 is 1 to 2 μmol/L, 3 orders of magnitude below the millimolar concentrations of intracellular adenine nucleotide pools.75 Therefore, ATP-dependent activation of the HSF1 regulatory pathway and the biochemical properties of molecular chaperones are unlikely to be adversely affected during periods of transient ischemia or reversible myocardial ischemic injury.

Proof of principle indicating a cardioprotective effect of Hsp70 in transgenic animals subjected to ischemia/reperfusion suggests that pharmacological or genetic methods to increase stress protein expression in the myocardium of patients at risk of acute ischemic events might limit ischemic injury.82 However, additional basic knowledge is needed regarding (1) their relationships to other endogenous pathways involved in myocardial protection from oxidative stress/damage, (2) functional specificity among chaperone members of the HSP multigene family, and (3) the contribution of this pathway during acute ischemia and other physiological states that trigger the heat shock response, before clinical application.

Stress Proteins and Antioxidant Pathways for Cardioprotection

Since the 1970s, the hypothesis that free radical scavengers can ameliorate oxidative damage during ischemia/reperfusion has been pursued by clinicians and researchers.83 In model systems ranging from transgenic Drosophila to mice, overexpression of catalase, superoxide dismutase, or glutathione peroxidase tends to be protective against oxidative stress.84 85 86 Oxidative stress, from ischemia/reperfusion, also plays a central role in the injury of vital organs such as the brain, kidney, and heart. ROS are thought to contribute to ventricular dysfunction, or “myocardial stunning,” arrhythmias, and progressive cell damage or death after ischemic injury (Figure 1⇑).87 88 89 90

Discrepant results have been reported from attempts to deliver antioxidants during and after myocardial ischemia/reperfusion.91 92 Exogenous antioxidants, which are restricted to the interstitial spaces, may have limited ability to protect intracellular proteins against ROS. For example, the hydroxyl free radical (·OH), believed to be the main agent of oxidative damage, is so highly reactive with a typical substrate that its half-life at 37°C is 7×10−10 seconds.93 Thus, it is difficult to envision that the administration of exogenous antioxidants, at concentrations that are physiologically feasible, can effectively prevent ·OH-induced macromolecular damage. A potentially more effective strategy may be to physiologically minimize the production of ·OH. Indeed, overexpression of members of the HSP family may provide one such avenue. Several studies have reported that during protection against myocardial ischemia, upregulation of stress protein levels correlates with increases in the enzymatic activity of catalase, suggesting potential additive or synergistic interactions of these endogenous pathways against oxidative stress.40 94 95 An important unanswered question is whether functions of stress proteins, as molecular chaperones, complement the unique functions of antioxidant enzymes in protecting against oxidative stress/damage.

Molecular Chaperones of the Cytosol/Nuclear Compartments

The Table⇓ shows the major classes of HSPs, the intracellular compartments, their putative functions, and potential significance in cardiovascular biology.

View this table:
Table 1.

Major Classes of HSPs in Cardiovascular Biology

Hsp70 Chaperones

Members of the Hsp70 family are the most widely studied and abundant group in eukaryotic cells.96 In the cytosol, Hsp70 binds to nascent polypeptides before their release from the ribosome.97 All members of the Hsp70 chaperone class possess two distinct domains: a highly conserved N-terminal ATPase domain and a more divergent C-terminal domain, which binds short hydrophobic peptides of target substrates98 99 (Figure 2A⇑). Hsp70 chaperone function requires the N-terminal ATPase domain, which, interestingly, is similar structurally to rabbit skeletal muscle actin despite little sequence similarity.100

These structure/functional relationships of Hsp70 likely confer in vivo chaperone activity in cardioprotection. In this regard, virtually nothing is known about the constitutive Hsc70 chaperone, which shares >80% sequence homology with Hsp70. Conceivably, modest upregulation of the constitutive Hsc70 could promote substantial cardioprotective benefit. However, upregulation of HSPs beyond a critical threshold may have deleterious cellular consequences.101 Distinct functions between Hsp70 members were reported recently to exist in regions outside the peptide binding domain, suggesting additional levels of complexity to chaperone functions in vivo.102

Hsp90 Chaperones

Figure 2⇑ shows that the chaperone Hsp90 is a component of the reaction cycle involving the chaperone Hsc70 complex and newly synthesized proteins. In addition, members of the Hsp90 family, Hsp90α and Hsp90β, which constitute 1% to 2% of the total soluble cytoplasmic proteins, have the best characterized in vivo functional relationships with target proteins, the steroid hormone receptors.103 Hsp90 with chaperone partners, Hsp70 and Hsp56, directly binds, stabilizes, and maintains the aporeceptor complex in an inactive conformation. Ligand binding (eg, estrogen) to the aporeceptor complex triggers ATP hydrolysis by Hsp90, which dissociates from an “activated” receptor that can now bind to the sequence-specific recognition motif and induce the transcription of target genes.104 In addition, elevated levels of Hsp90 expression destabilize the estrogen receptor/estrogen responsive element complex and downregulate estrogen-responsive target gene expression, indicating a regulatory feedback loop.105

Hsp90 chaperone functions are mediated by signal transduction pathways involving various protein kinases of both tyrosine and serine-threonine types, casein kinase II, the heme-regulated eIF-2α, and a variety of other cellular proteins, such as calmodulin, actin, and tubulin (reviewed in Reference 106106 ). Finally, Hsp90 chaperones of Saccharomyces cerevisiae are essential for survival under all conditions, supporting their important physiological roles in lower eukaryotes.107

Cytosolic Chaperones of Special Interest in Cardiac and Vascular Biology

Unlike the ubiquitous Hsp70 and Hsp90 counterparts, specific members of the small MW HSPs (HO-1 or Hsp32, Hsp27, αB-crystallin, and Hsp20 chaperones) exhibit tissue-restricted expression, suggesting potential specialized properties in the cardiovascular system.

Inducible HO (Hsp32)

HO is the rate-limiting enzyme in the degradation of heme to biliverdin (a potent antioxidant), molecular iron, and carbon monoxide. Three related single-copy genes encode HO isoforms: HO-1, HO-2, and HO-3.108 109 110 HO-1 is a bona fide 32-kDa stress protein (Hsp32) that is induced by diverse physiological stresses, including hypoxia, ischemia/reperfusion, hemin, hydrogen peroxide, and several heavy metals (selenium, arsenite, cobalt, cadmium, and stannous ions).108 109 110 Inducible Hsp32 (HO-1), the most widely expressed isoform, is present in myocardial cells.111

Hsp32, like the inducible form of NO synthase mediates guanylyl cyclase–dependent platelet inhibition and vasodilation of VSMCs.112 113 114 However, physiologically relevant hemodynamic forces (shear stress and cyclic strain) induce HO-1 mRNA expression but not inducible NO synthase expression, suggesting specificity of this stress response pathway to physiological signals.115 Either endogenously released or exogenous administered NO induces a 3- to 6-fold increase in Hsp32 (HO-1) gene expression and CO production in VSMCs116 ; similarly, the inhibitor tin protoporphyrin-IX prevents platelet aggregation through induction of HO-1 gene expression and CO production in aortic VSMCs.115 In rat VSMCs, angiotensin II treatment decreases Hsp32 (HO-1) mRNA expression in a calcium-dependent manner.117 However, angiotensin II–induced hypertension increases Hsp32 (HO-1) mRNA expression in rat aorta, suggesting the overriding influences of hemodynamic factors in vivo.118

Several regulatory pathways are involved in the induction of Hsp32 gene expression, most notably the HSF1 and the hypoxia-inducible transcription factor-1 pathways.119 120 121 122 Although direct evidence of a chaperone function of Hsp32 is lacking, its overexpression in several cell types protects against oxidative stress/damage.123 124 125 Accordingly, studies to define the precise regulatory pathways stimulated by heavy metals, hypoxia, and oxidative stress could provide novel insight into the biological roles of Hsp32 (HO-1) in modulating oxidative stress/damage during ischemia/reperfusion, vascular tone (eg, hypertension), and inhibition of platelet aggregation and/or VSMC proliferation after balloon angioplasty.

Hsp25/27 Chaperone

After its discovery as an inhibitor of actin polymerization,126 chaperone Hsp 25/27 (Hsp25 in mice and Hsp27 in humans) has been demonstrated to play a major role in actin filament dynamics in diverse cell types. Physiological stimuli (oxidative stress, cytokines, and growth factors) dramatically increase the phosphorylation of human Hsp27 at Ser15, Ser78, and Ser83 residues, which is essential for acquired tolerance.127 128 129 Hsp25/27 phosphorylation is catalyzed by the MAPKs (p38-MAPKs, JNKs, or SAPKs) and ERKs.130 In the perfused adult heart, both p38-MAPK and JNK/SAPK are activated after ischemia/reperfusion.131 In response to ROS treatment, activation of p38-MAPK increases MAPKAP kinase 2 activity, which phosphorylates Hsp27.132

In human endothelial cells, inhibition of vascular endothelial growth factor–induced p38-MAPK activation abolishes Hsp27 phosphorylation, actin polymerization, and cell migration, suggesting a possible link between Hsp27 and angiogenesis.133 Together, available evidence places the p38-MAPK as an upstream activator of stress-inducible Hsp25/27 phosphorylation, and this pathway underlies the effect of p38-MAPK on the reorganization of filamentous actin, accumulation of stress fibers, and the recruitment of vinculin at focal adhesion sites.134 It will be important next to determine whether Hsp25/27 exerts vasoprotective actions in response to hemodynamic forces or vessel wall injury. However, direct analysis will likely require an Hsp27 gene knockout model.

αB-Crystallin Chaperone (Hsp22)

Whereas Hsp27 is detected in endothelial cells, VSMCs, and cardiomyocytes, the αB-crystallin chaperone is expressed in cardiomyocytes only.135 Both Hsp27 and αB-crystallin are structurally related bona fide HSPs with in vitro chaperone activity but, unlike Hsp70, are not ATP-binding proteins.136 137 138 139 Heightened interest into the regulation and function of αB-crystallin protein (Hsp22), a major structural protein of the ocular lens, is related to its tissue-restricted expression in striated myogenic lineages with high oxidative capacity, such as the heart and type I skeletal muscle fibers.140 In nonlenticular tissues, αB-crystallin postnatal expression increases and reaches its highest levels in the adult heart (≈1% to 3% of the total soluble protein), followed by skeletal muscle and the kidney.140 Previous immunohistochemical studies have localized the highest αB-crystallin expression in the cardiac conduction fibers of the adult heart.141 Whether an alteration of αB-crystallin expression could lead to abnormalities of the conduction system is presently unknown but raises an intriguing possibility.

Although αB-crystallin expression has been localized to Z bands of the cytoskeleton, in a pattern similar to desmin and actin,142 recent studies suggest that this interaction is much more transient and dynamic with respect to intracellular targets, depending on the physiological conditions. In unstimulated cardiac myocytes, biochemical studies indicate that αB-crystallin is highly soluble and remains in the cytosolic fraction; heat or ischemia triggers rapid translocation of αB-crystallin into the insoluble cytoskeletal/nuclear fractions, aggregation, and specific interactions at Z bands (Reference 142142 and I.J. Benjamin, unpublished data, 1998). The physiological significance for the tendency of both αB-crystallin and Hsp25/27 to form large hetero-oligomeric complexes (500 to 800 kDa) both in vivo and in vitro after physiological stresses remains a mystery.143 144 Although αB-crystallin chaperone provides cytoprotection to cardiomyocytes,74 the regulatory mechanisms of posttranslation modifications such as phosphorylation, glycation, and deacetylation on αB-crystallin function await direct analysis in the cardiovascular system.

Stress Proteins and Striated Muscle Development and Differentiation

Increased small MW HSP chaperone expression has been described during periods associated with increased protein synthesis, protein degradation, and cellular reorganization, such as myogenic differentiation and embryogenesis.145 The tissue-restricted expression of αB-crystallin during skeletal muscle myogenesis may require the MyoD family of basic helix-loop-helix transcription factors, which bind the essential E-box enhancer contained in αB-crystallin promoter.146 147 We recently reported that expression of αB-crystallin, but not Hsp27, is directly linked to increases in oxidative metabolism in skeletal muscle after chronic nerve stimulation.148 However, the physiological role of upregulation of Hsp27 expression, which precedes early differentiation of murine embryonic stem cells, remains to be established in myogenic lineages.149

Much less is known about the regulatory mechanisms involved in αB-crystallin–restricted expression in cardiac myocytes. αB-Crystallin is abundantly expressed in early cardiac development beginning at embryonic day 8.5, suggesting a role either as a structural protein or as a molecular chaperone in myofiber stabilization.150 Since Myo-d–like factors are absent in the heart, in vitro binding studies of cardiac nuclear extracts have implicated the transcriptional activities of an upstream stimulating factor at the E-box element and the serum response factor at a reverse CArG box in the αB-crystallin promoter.151 So far, an in vivo developmental survey reveals that αB-crystallin expression is unaffected in skeletal muscle of myf5 null mice or the heart of d-HAND null mice at embryonic day 9.0 (I.J. Benjamin, unpublished data, 1998).152 153

Other Cytosolic/Nuclear Chaperones

Several other HSPs that exist in the cytosolic/nuclear compartment are of potential interest in cardiovascular biology. For example, the cytosolic 20-kDa protein, p20, is abundantly expressed in heart, skeletal, and smooth muscle and copurifies with the chaperones αB-crystallin and Hsp27.154 155 Although p20 expression is induced by neither heat nor chemical stress, it contains the homologous C-terminal “α-crystallin domain” shared by all members of the small MW HSPs.138 In VSMCs, p20 is a substrate for both cAMP and cGMP protein kinases, suggesting a regulatory role to postulated functions in physiological maintenance of vascular tone and adaptation to vessel wall injury.156

A fourth member of the small HSPs (besides Hsp27, αB-crystallin, and p20), a myotonic dystrophy protein kinase–binding protein associates and increases the activity of dystrophy protein kinase and prevents its heat-induced denaturation in vitro.157 Myotonic dystrophy protein kinase, unlike Hsp27 or αB-crystallin, is upregulated in the skeletal muscle of patients with myotonic dystrophy, suggesting that this novel protein may be involved in the pathogenesis of this disease.157

Members of the Hsp110 family exhibit chaperone and cytoprotective functions, although details about their relative expression in myocardial cells and regional distribution in the cardiovascular system await further characterization.158 Additional Hsp110 family members include Hsp105, Apg-1, and Osp94.159 160 161 There is intense interest in identifying a mammalian homologue of yeast Hsp104, which, instead of preventing protein aggregation, seems to resolubilize insoluble protein aggregates.162

Mitochondrial Hsp70 Chaperone System

All organisms possess ATP-dependent mechanisms for protein folding and assembly within organelles.11 13 Translocation of proteins across the mitochondrial membrane requires mitochondrial chaperone Hsp70 in the matrix, where folding into the native state is completed13 (see Figure 1⇑).

Mitochondrial Chaperonin System

Besides Hsp70-like chaperones, mitochondrial chaperonins Hsp60 and Hsp10 constitute a separate system that provides a sequestered environment for folding a subset of proteins in vivo.163 These 7-membered rings are arranged as cylindrical structures in which ATP-dependent protein folding occurs in their central cavity.164 Evidence from in vitro studies suggests the Hsp70 chaperones and chaperonin systems function cooperatively in protein folding and assembly in eukaryotes (reviewed in Reference 1313 ).

Cytosolic Chaperonin System

TRiC chaperonin is considered the functional equivalent of chaperonin Hsp60/Hsp10 in the eukaryotic cytosol. The TRiC complex, which consists of either 8- or 9-membered double rings of ≈55 to 65 kDa subunits, is required for folding of actin and tubulin in vivo.165 Chaperonin TRiC requires additional components, such as Hsp40, which stimulates the Hsc70 ATPase, for protein folding in the cytosol77 166 (see Figure 2⇑). Available evidence suggests that TRiC chaperonin functions in the final stages of folding during translation of a limited number of polypeptide domains.13

Implications

Mitochondrial chaperones and chaperonins are only modestly induced by physiological stress in cardiomyocytes and the heart.167 However, the location of mitochondrial Hsp70 chaperones and chaperonins at major sites of ROS production could serve to complement both enzymatic and nonenzymatic defense mechanisms to diminish oxidative injury and increase the rate of physiological recovery after ischemic injury.168 169 Whether overexpression of either mitochondrial Hsp75 chaperone or chaperonin can provide equivalent or superior protection against ischemic injury is presently unknown. Another important question concerns whether the overlapping functions of Hsp70 chaperones and Hsp60 or TRiC/Hsp40 chaperonin systems are coordinated for de novo protein folding and potential cytoprotection during the pathogenesis of heart disease.

Molecular Chaperones in ER

Glucose-Regulated Proteins

Analysis of ER chaperones may be of particular clinical interest, because the ER functions to degrade or repair proteins damaged after myocardial ischemia or after mutant proteins (eg, CFTR or thyroglobulin) fail to fold properly.11 170 171 Anoxia, glucose starvation, and calcium ionophores induce members of the Ca2+-binding glucose-regulated class of stress proteins, Grp170, Grp94, and Grp78/BiP.11 172 Variable changes in the expression of Grp78 protein have been reported after ischemia.173 174 Although “guilt by association” with cytosolic chaperones is the presumed role of chaperone Grp function in protein surveillance and quality control, more studies of their expression are needed in pathophysiological states associated with the expression, posttranslational glycosylation, and secretion of abnormal proteins via the ER-Golgi pathway.

Hsp47 Chaperones

The 47-kDa collagen-binding glycoprotein Hsp47 is a member of the serpin (serine protease inhibitor) superfamily and is highly induced by heat stress or pathophysiological states (eg, hepatic fibrosis) associated with increased collagen synthesis.175 Hsp47 resides in the ER and contains the C-terminal Arg-Asp-Glu-Leu ER retention signal.176 Hsp47 binds transiently to collagen types I to IV and avidly to denatured collagen substrates; thus, its role in procollagen processing and transport seems firmly established.177 Future studies must now address the likely biological and clinical relevance of Hsp47 expression at the onset and progression of pathophysiological states, such as myocardial infarction, idiopathic and hypertrophic cardiomyopathies, and hypertension, in which myocardial fibrosis is prominently featured.178

Current Challenges and Future Directions

Physiological recovery of the ischemic heart begins within minutes, but the rate of cellular ischemic repair, which may last for days to weeks, is critical for the reduction of subsequent cardiovascular morbidity and mortality. The idea that stress proteins can speed the physiological recovery of reversible myocardial injury is based on experimental evidence indicating that multiple proximate “signals” can activate the heat shock response and, thereby, evoke the endogenous protective mechanisms of Hsps. Major clinical events such as unstable angina, recurrent occlusion after thrombolytic therapy, and acute exacerbation of chronic angina are potential physiological inducers of cytoprotective stress proteins. The next logical step would be to consider the possibility that related members of the multigene stress protein family confer similar or additional functional benefits. Because ischemia and other physiological perturbations disrupt the normal structure-function relationships of intracellular proteins, future studies must establish whether molecular chaperones, either alone or in combination, alleviate ischemic damage by accelerating physiological recovery of the myocardial cell in the intact organism.

Experimental Models for Stress Protein Research

Transgenic models of Hsp70 overexpression (gain of function) and hsf1-deficient mice (loss of function), and their subsequent characterization, are beginning to illuminate their physiological roles in vivo.16 17 18 36 One exciting direction of such efforts could lead to integrated approaches into the physiological roles of entire systems or regulatory networks in genetically modified animal models of human diseases. However, the wealth of existing knowledge of physiological studies in animals larger than the mouse should not be disregarded. Studies to define the role of HSP expression in myocardial stunning using conscious animals could justify the development of transgenic rat and rabbit models. Potential limitations of such strategies include substantially greater costs from the longer gestation periods, longer time to reach sexual maturity, and smaller litter sizes of such larger species. However, investigators with expertise in molecular biology and molecular physiology undertaking collaborative projects increase the chances of success, while avoiding the duplication of efforts.

Does Stress-Inducible Expression of HSP Genes Affect Infarct Size, Arrhythmogenesis, and Myocardial Remodeling After Acute Myocardial Infarction?

Previous studies have demonstrated that pretreatment (24 hours) with heat stress attenuates free radical release in the isolated rat heart95 and reduces the amount of arrhythmias, a major functional hallmark of ischemia/reperfusion injury (reviewed in Reference 9292 ). Together, these studies correlate potential interactions between these protective pathways but are inadequate to establish a cause and effect relationship. The development of an HSF1 gene knockout mouse model provides a powerful experimental approach to determine whether a deficiency in stress-inducible HSP synthesis, during physiological perturbations such as myocardial ischemia, affects the outcome of postinfarction injury and the repair mechanisms in the intact organism. Results of such studies can help establish causality, elucidate potential mechanisms by which HSP synthesis relates to myocardial ischemia, and evaluate the participation of stress proteins during early and late ischemic preconditioning. Timely characterization of several knockout models, currently in development in laboratories worldwide, should continue to foster fruitful collaborations among investigators.179 Further progress should accelerate the flow of new knowledge into related areas such as postischemic reactive and reparative fibrosis,180 postreperfusion inflammation,181 and myocardial stunning.89 182

Stress Protein Expression and Mechanisms of Ischemic Preconditioning

Ischemic preconditioning is the most powerful experimental maneuver that reproducibly protects the heart against subsequent ischemic challenge.183 However, controversy exists about the precise roles of stress proteins in this well-characterized phenomenon.184 Several mechanisms involving protein kinase C, adenosine receptors, and their relationships to signal transduction pathways have been implicated in ischemic preconditioning.185 Sufficient evidence indicates a lack of correlation between stress-inducible expression (eg, Hsp70) and early preconditioning, which is short-lived and lasts between 1 and 3 hours, depending on the model and species.186

Is the Chaperone Family of Stress Proteins Unlikely to Have Physiological Relevance in Early Preconditioning?

In our opinion, studies in this area have either prematurely dismissed or paid inadequate attention to the potential importance of the small MW Hsps, such as αB-crystallin and Hsp27. These chaperones seem likely to be candidates for the “first line of defense” against nonlethal stress. Whether oligomerization of small MW Hsps contributes to the mechanical stability or speculated role of the cytoskeleton in ischemic protection of the cardiac myocyte is presently unknown.187 188 Both αB-crystallin and Hsp27 gene knockout models, currently in development, could directly address this hypothesis.

Similarly, studies are needed to address the correlation between late preconditioning and stress protein expression. Twenty-four hours after an initial ischemic stress, several studies have reported increases in Hsp60 and Hsp70 synthesis in rabbits,41 Hsp70 in pigs,182 and manganese-SOD in dogs189 190 and delayed ischemic tolerance or late preconditioning. Therefore, a fundamental question is whether a direct relationship exists between stress protein expression and late preconditioning.191 192 193 A more detailed assessment of the specific role of individual Hsp in cardioprotection is also required. Attempts to determine the mechanism of the cardioprotective ATP-sensitive potassium channel by use of inhibitors have found a lack of correlation with stress protein Hsp70 expression.194 However, approaches using specific inhibitors are inadequate for establishing specificity, to any degree of certainty, beyond the proteins under investigation.195

Molecular Chaperones and Cell Death Pathways

Stress proteins are ideal candidates to play key regulatory roles in cell survival and death pathways involving DNA damage and protein synthesis, repair, and degradation. Maneuvers that increase Hsp70 expression after heat shock, sodium butyrate exposure, and constitutive or regulated overexpression inhibit apoptosis in a variety of cell types.196 197 198 The proto-oncogene c-myc potentiates heat shock–induced apoptosis199 200 ; in contrast, Bcl-2 overexpression augments thermotolerance-induced cellular survival.201 Tissue-specific expression of Hsp70-2 prevents apoptosis in certain mitotic cells through a mechanism involving cell cycle control.202 Hsp70 chaperone function in regulating apoptosis may be at the level of signal transduction, as it has been implicated in the stress-activated kinase pathway.203

Recent studies in our laboratory using hsf1-deficient cultured cells have established the role of stress-inducible Hsps to render cells thermotolerant to heat-induced apoptosis.36 The present study provides a genetic model to examine potential interdependent relationships between stress-inducible of Hsps and the mechanisms involved in cell survival and/or cell death pathways. Sublethal heat stress protects mitochondria against oxidative stress and prevents cell death by apoptosis.204 Given their strategic locations in all major organelles, it is tempting to speculate that multiple Hsps may combat oxidative stress/damage by refolding damaged repressors of the cell death pathway or preventing their degradation. Alternatively, repressing the release of suicide activators such as cytochrome c could occur through interactions with mitochondrial chaperones and chaperonins (Figure 1⇑).

In addition, results of several recent studies have implicated the small MW Hsp25/27 in cell survival pathways involving cell differentiation and oxidative stress/damage. Previous studies have demonstrated that overexpression of Hsp25/27, like the antiapoptotic protein Bcl-2, increases the levels of the antioxidant glutathione and resistance to Fas/APO-1–mediated apoptosis, although whether this occurs directly remains unclear.205 Withdrawal of mouse embryonic stem cells from the cell cycle induces upregulation of Hsp25/27 mRNA, which is accompanied by decreases in phosphorylation and increases in oligomerization of Hsp25/27 protein.149 Antisense reduction of Hsp25/27 reverses these changes through the prolongation of the cell cycle, reduction in glutathione levels, and acceleration toward apoptosis. Together, these provocative findings suggest that during proliferation and differentiation of myocardial cells, the Hsp25/27 chaperone, and others, can reduce oxidative stress/damage and prevent apoptosis through a novel redox-dependent mechanism.206

Does Stress-Inducible Expression of HSP Genes Affect the Natural History of Chronic Cardiovascular Diseases, Including Aging?

Numerous studies have correlated the induction of Hsp expression and pressure overload by aortic banding, acute hypertension, exposure to vasoactive agents or left ventricular hypertrophy, and growth factor expression in several cell types.207 208 209 Decreases in the expression of HSP genes and the DNA-binding activity of HSF1 are reported to occur during the aging process in the rodent myocardium.210 There is increasing evidence suggesting that oxidative stress/damage may be a major causal factor in the aging process.211 The level of oxidative stress and the susceptibility of tissues to experimentally induced oxidative stress seem to increase during the aging process. Whether the increased amounts of molecular oxidative damage, observed during the aging process, are causally associated with a decreased activity of HSF1 and, by implication, Hsp gene expression is presently unknown. The availability of transgenic and gene knockout models will enable future studies to establish the role of stress-inducible heat shock gene expression during normal aging or physiological adaptation to disease-associated cardiac risk factor(s).

Molecular Chaperones in Cardiac Disease States Caused by Expression of Mutant Proteins

Elevated levels of misfolded or denatured proteins, as well as microinjection of abnormal proteins, are potent inducers of HSP gene expression.14 59 Recent studies indicating that the Hsc70 chaperone interacts indirectly with the CFTR harboring the common ΔF508 folding mutation support this general notion of their biological role in human diseases.20

From the perspective of chaperone biology, cardiac diseases that arise from mutations in genes encoding components of the contractile apparatus or ion channel proteins are essentially problems of abnormal proteins. Multiple mutations of sarcomeric proteins have been implicated in the pathogenesis of familial hypertrophic cardiomyopathy, including myosin heavy and light chains, troponin I and T subunits, myosin binding protein C, and tropomyosin (Reference 66 and reviewed in Reference 77 ). Whereas chaperone Hsp27 plays a role in actin polymerization and chaperonin TRiC is involved in actin and tubulin folding, the physiological role of chaperone and chaperonin systems in folding and assembly of sarcomeric structures, under normal conditions or in disease, remains a mystery. Conceivably, chaperones can influence either the repair or degradation of mutant sarcomeric proteins, which, ultimately, affect the structure-function relationships and phenotype of the disease.212 In vitro analyses are first needed to determine whether chaperone function can affect productive protein folding caused by the relevant mutations, which can be validated in appropriate animal models.18 213

Molecular Chaperones in Vascular Biology

Numerous opportunities exist to dissect chaperone functions during the synthesis and secretion of biological active peptides and proteins, cellular proliferation, intracellular signaling, and cytoskeletal rearrangement. Results of such studies may identify the specific HSP protein targets and the specificity among the various cell types in promoting the vascular protective effects of estrogen.214 215 The essential roles of Hsp90 and cochaperones in steroid receptor biology suggest that HSP chaperones play a clinically significant role in the effects of hormonal replacement therapy in postmenopausal women.216 217 Epidemiological studies have found that the protective benefit against coronary heart disease in premenopausal women is abolished in the postmenopausal years.218 219 220 Potential protective actions of estrogen have been attributed to its antioxidative and vasoprotective properties, lowering of blood lipids and lipoproteins, and direct effects on the vessel wall.221 It will be important to define whether stress-inducible Hsp expression in genetically modified mice plays a role in the vascular response to injury in male and female animals.215

Molecular Chaperone and Immunological Diseases

In contrast to their well-established cytoprotective roles, certain stress proteins have been implicated in the pathogenesis of cardiovascular diseases. For example, elevated serum levels of antibodies against the bacterial homologue of mammalian Hsp60 have been demonstrated in patients with cardiomyopathy and diabetes, in asymptomatic individuals with carotid stenosis, and in atherosclerotic lesions in rabbits and humans (reviewed in Reference 222222 ). One hypothesis is that autoimmune disease results from cross-reactivity of immunogenic peptides, which are derived from bacterial and mitochondrial chaperones and Hsp60 (chaperonin) and are recognized by activated γ/δ T lymphocytes.223 224 Humoral immune responses and seropositive markers against the Hsp70 family (especially ER Grp78 and Hsc70) of the protozoan parasite Trypanosoma cruzi have been implicated in the pathogenesis of Chagas’ disease,224A the most common cause of congestive heart failure in Latin America (see Table⇑). Although these correlative studies have inherent limitations, future research to establish causality could open avenues to develop vaccines or other novel therapies for treatment and prevention.

Potential Therapeutic Applications of Molecular Chaperones

Strategies that could increase the rate of physiological recovery after postinfarction stunning and ventricular dysfunction remain important goals in the management of patients with acute myocardial infarction. Because maneuvers using either tissue or whole body hyperthermia are cumbersome and impractical in conscious humans, pharmacological strategies that increase stress protein expression for isothermal protection have potential merit against ischemic damage to the heart, kidney, and brain. Proteasome inhibitors, which transiently elevate the level of unfolded proteins inside cells, is one potential approach.225 Alternative approaches may involve the development of small molecules and peptides226 226A that mimic the in vivo actions of chaperones with therapeutic benefits.

Perspectives

The role of stress proteins in cardioprotection has been acknowledged as one of the most important future directions of research in ischemic heart disease.227 Since the number of affected individuals is so large, a therapeutic intervention that contributes to a small change in post–myocardial infarction morbidity and mortality, for example, can have dramatic effects on overall clinical outcomes. Opportunities to address the physiological roles of cytoprotective chaperones in cardiac diseases need to be expanded to include their likely roles during chronic conditions (atherosclerotic, hypertension, diabetes, genetic disorders, and valvular heart disease) that converge through common pathways, resulting in heart failure and sudden death. Strategic alliances among research teams could forge new directions and accelerate progress in this promising area, which, ultimately, could succeed in exploiting endogenous pathways to enhance physiological health and to reduce physiological attrition associated with cardiovascular diseases.

Selected Abbreviations and Acronyms

CFTR=cystic fibrosis transmembrane conductance regulator
ER=endoplasmic reticulum
ERK=extracellularly responsive kinase
Grp=glucose-related protein
HO=heme oxygenase
Hsc=heat shock cognate
HSF=heat shock transcription factor
HSP=heat shock family of stress proteins
Hsp=heat shock protein
JNK=c-Jun N-terminal kinase
MAPK=mitogen-activated protein kinase
MAPKAP=MAPK-activated protein kinase
MW=molecular weight
ROS=reactive oxygen species
SAPK=stress-activated protein kinase
TRiC=TCP-1 ring complex
VSMC=vascular smooth muscle cell

Acknowledgments

Dr Benjamin was supported by the American Foundation for Medical Research, the National Institutes of Health, and an Established Investigator Award from the American Heart Association. We thank R. S. Williams, R. Meidell, A. Davis, P. Thomas, and R. Sohal for their critical comments regarding our manuscript.

  • Received February 4, 1998.
  • Accepted March 25, 1998.

References

  1. 1.↵
    Rannels DE, Chua B, Kao R, Morgan HE. Inhibition of protein degradation in the energy-poor heart. Adv Myocardiol. 1980;1:535–546.
    OpenUrlPubMed
  2. 2.↵
    Westfall MV, Solaro RJ. Alterations in myofibrillar function and protein profiles after complete global ischemia in rat hearts. Circ Res. 1992;70:302–313.
    OpenUrlAbstract/FREE Full Text
  3. 3.↵
    Yoshida Y, Shiga T, Imai S. Degradation of sarcoplasmic reticulum calcium-pumping ATPase in ischemic-reperfused myocardium: role of calcium-activated neutral protease. Basic Res Cardiol. 1990;85:495–507.
    OpenUrlCrossRefPubMed
  4. 4.↵
    Gao WD, Atar D, Liu Y, Perez NG, Murphy AM, Marban E. Role of troponin I proteolysis in the pathogenesis of stunned myocardium. Circ Res. 1997;80:393–399.
  5. 5.↵
    Tanigawa G, Jarcho JA, Kass S, Solomon SD, Vosberg HP, Seidman JG, Seidman CE. A molecular basis for familial hypertrophic cardiomyopathy: an alpha/beta cardiac myosin heavy chain hybrid gene. Cell. 1990;62:991–998.
    OpenUrlCrossRefPubMed
  6. 6.↵
    Geisterfer-Lowrance AA, Kass S, Tanigawa G, Vosberg HP, McKenna W, Seidman CE, Seidman JG. A molecular basis for familial hypertrophic cardiomyopathy: a beta cardiac myosin heavy chain gene missense mutation. Cell. 1990;62:999–1006.
    OpenUrlCrossRefPubMed
  7. 7.↵
    Vikstrom KL, Leinwand LA. Contractile protein mutations and heart disease. Curr Opin Cell Biol. 1996;8:97–105.
    OpenUrlCrossRefPubMed
  8. 8.↵
    Curran ME, Splawski I, Timothy KW, Vincent GM, Green ED, Keating MT. A molecular basis for cardiac arrhythmia: HERG mutations cause long QT syndrome. Cell. 1995;80:795–803.
    OpenUrlCrossRefPubMed
  9. 9.↵
    Keating MT. The long QT syndrome: a review of recent molecular genetic and physiologic discoveries. Medicine (Baltimore). 1996;75:1–5.
    OpenUrlCrossRefPubMed
  10. 10.↵
    Lindquist S, Craig EA. The heat-shock proteins. Annu Rev Genet. 1988;22:631–677.
    OpenUrlCrossRefPubMed
  11. 11.↵
    Gething MJ, Sambrook J. Protein folding in the cell. Nature. 1992;355:33–45.
    OpenUrlCrossRefPubMed
  12. 12.↵
    Ellis RJ, Hemmingsen SM. Molecular chaperones: proteins essential for the biogenesis of some macromolecular structures. Trends Biochem Sci. 1989;14:339–342.
    OpenUrlCrossRefPubMed
  13. 13.↵
    Hartl F. Molecular chaperones in cellular protein folding. Nature. 1996;381:571–579.
    OpenUrlCrossRefPubMed
  14. 14.↵
    Pelham HR. Speculations on the functions of the major heat shock and glucose-regulated proteins. Cell. 1986;46:959–961.
    OpenUrlCrossRefPubMed
  15. 15.↵
    Hightower LE. Heat shock, stress proteins, chaperones, and proteotoxicity. Cell. 1991;66:191–197.
    OpenUrlCrossRefPubMed
  16. 16.↵
    Plumier JC, Ross BM, Currie RW, Angelidis CE, Kazlaris H, Kollias G, Pagoulatos GN. Transgenic mice expressing the human heat shock protein 70 have improved post-ischemic myocardial recovery. J Clin Invest. 1995;95:1854–1860.
  17. 17.↵
    Marber MS, Mestril R, Chi SH, Sayen MR, Yellon DM, Dillmann WH. Overexpression of the rat inducible 70-kD heat stress protein in a transgenic mouse increases the resistance of the heart to ischemic injury. J Clin Invest. 1995;95:1446–1456.
  18. 18.↵
    Radford NB, Fina M, Benjamin IJ, Moreadith RW, Graves KH, Zhao P, Gavva S, Wiethoff A, Sherry AD, Malloy CR, Williams RS. Cardioprotective effects of 70-kDa heat shock protein transgenic mice. Proc Natl Acad Sci U S A.. 1996;93:2339–2342.
    OpenUrlAbstract/FREE Full Text
  19. 19.↵
    Thomas PJ, Qu BH, Pedersen PL. Defective protein folding as a basis of human disease. Trends Biochem Sci. 1995;20:456–459.
    OpenUrlCrossRefPubMed
  20. 20.↵
    Strickland E, Qu BH, Millen L, Thomas PJ. The molecular chaperone Hsc70 assists the in vitro folding of the N-terminal nucleotide-binding domain of the cystic fibrosis transmembrane conductance regulator. J Biol Chem. 1997;272:25421–25424.
    OpenUrlAbstract/FREE Full Text
  21. 21.↵
    Ritossa F. Discovery of the heat shock response. Cell Stress Chaperones. 1996;1:97–98.
    OpenUrlCrossRefPubMed
  22. 22.↵
    Tissieres A, Mitchell HK, Tracy UM. Protein synthesis in salivary glands of Drosophila melanogaster: relation to chromosome puffs. J Mol Biol. 1974;84:389–398.
    OpenUrlCrossRefPubMed
  23. 23.↵
    Hightower LE, Hendershot LM. Molecular chaperones and the heat shock response at Cold Spring Harbor. Cell Stress Chaperones. 1997;2:1–11.
    OpenUrlCrossRefPubMed
  24. 24.↵
    Jennings RB, Ganote CE, Reimer KA. Ischemic tissue injury. Am J Pathol. 1975;81:179–198.
    OpenUrlPubMed
  25. 25.↵
    Welch WJ. How cells respond to stress. Sci Am. 1993;268:56–64.
    OpenUrl
  26. 26.↵
    Welch WJ, Kang HS, Beckmann RP, Mizzen LA. Response of mammalian cells to metabolic stress: changes in cell physiology and structure/function of stress proteins. Curr Top Microbiol Immunol. 1991;167:31–55.
    OpenUrlPubMed
  27. 27.↵
    Laszlo A. The thermoresistant state: protection from initial damage or better repair? Exp Cell Res.. 1992;202:519–531.
    OpenUrlCrossRefPubMed
  28. 28.↵
    Neely JR, Grotyohann LW. Role of glycolytic products in damage to ischemic myocardium: dissociation of adenosine triphosphate levels and recovery of function of reperfused ischemic hearts. Circ Res. 1984;55:816–824.
    OpenUrlAbstract/FREE Full Text
  29. 29.↵
    Patriarca EJ, Maresca B. Acquired thermotolerance following heat shock protein synthesis prevents impairment of mitochondrial ATPase activity at elevated temperatures in Saccharomyces cerevisiae. Exp Cell Res. 1990;190:57–64.
    OpenUrlCrossRefPubMed
  30. 30.↵
    Patriarca EJ, Kobayashi GS, Maresca B. Mitochondrial activity and heat-shock response during morphogenesis in the pathogenic fungus Histoplasma capsulatum. Biochem Cell Biol. 1992;70:207–214.
    OpenUrlPubMed
  31. 31.↵
    Panniers R, Stewart EB, Merrick WC, Henshaw EC. Mechanism of inhibition of polypeptide chain initiation in heat-shocked Ehrlich cells involves reduction of eukaryotic initiation factor 4F activity. J Biol Chem. 1985;260:9648–9653.
    OpenUrlAbstract/FREE Full Text
  32. 32.↵
    Scorsone KA, Panniers R, Rowlands AG, Henshaw EC. Phosphorylation of eukaryotic initiation factor 2 during physiological stresses which affect protein synthesis. J Biol Chem. 1987;262:14538–14543.
    OpenUrlAbstract/FREE Full Text
  33. 33.↵
    Zapata JM, Maroto FG, Sierra JM. Inactivation of mRNA cap-binding protein complex in Drosophila melanogaster embryos under heat shock. J Biol Chem. 1991;266:16007–16014.
    OpenUrlAbstract/FREE Full Text
  34. 34.↵
    Theodorakis NG, Morimoto RI. Posttranscriptional regulation of hsp70 expression in human cells: effects of heat shock, inhibition of protein synthesis, and adenovirus infection on translation and mRNA stability. Mol Cell Biol. 1987;7:4357–4368.
    OpenUrlAbstract/FREE Full Text
  35. 35.↵
    Arrigo AP, Suhan JP, Welch WJ. Dynamic changes in the structure and intracellular locale of the mammalian low-molecular-weight heat shock protein. Mol Cell Biol. 1988;8:5059–5071.
    OpenUrlAbstract/FREE Full Text
  36. 36.↵
    McMillan DR, Xiao X, Shao L, Graves K, Benjamin IB. Targeted disruption of heat shock transcription factor 1 abolishes thermotolerance and protection against heat-induced apoptosis. J Biol Chem. 1998;273:7523–7528.
    OpenUrlAbstract/FREE Full Text
  37. 37.↵
    Hargrove JL, Schmidt FH. The role of mRNA and protein stability in gene expression. FASEB J. 1989;3:2360–2370.
    OpenUrlAbstract
  38. 38.↵
    Yost HJ, Lindquist S. Heat shock proteins affect RNA processing during the heat shock response of Saccharomyces cerevisiae. Mol Cell Biol. 1991;11:1062–1068.
    OpenUrlAbstract/FREE Full Text
  39. 39.↵
    Dellavalle RP, Petersen R, Lindquist S. Preferential deadenylation of Hsp70 mRNA plays a key role in regulating Hsp70 expression in Drosophila melanogaster. Mol Cell Biol. 1994;14:3646–3659.
    OpenUrlAbstract/FREE Full Text
  40. 40.↵
    Currie RW, Karmazyn M, Kloc M, Mailer K. Heat-shock response is associated with enhanced postischemic ventricular recovery. Circ Res. 1988;63:543–549.
    OpenUrlAbstract/FREE Full Text
  41. 41.↵
    Marber MS, Latchman DS, Walker JM, Yellon DM. Cardiac stress protein elevation 24 hours after brief ischemia or heat stress is associated with resistance to myocardial infarction. Circulation. 1993;88:1264–1272.
    OpenUrlAbstract/FREE Full Text
  42. 42.↵
    Morimoto RI, Tissieres A, Georgopoulos C. Progress and perspectives on the biology of heat shock proteins and molecular chaperones. In: Morimoto RI, Tissieres A, Georgopoulos C, eds. The Biology of Heat Shock Proteins and Molecular Chaperones. Cold Spring Harbor, NY: Cold Spring Harbor Press; 1994.
  43. 43.↵
    Morimoto RI. Cells in stress: transcriptional activation of heat shock genes. Science. 1993;259:1409–1410.
    OpenUrlFREE Full Text
  44. 44.↵
    Wu C. Heat shock transcription factors: structure and regulation. Ann Rev Cell Dev Biol. 1995;11:441–469.
    OpenUrlCrossRefPubMed
  45. 45.↵
    Sorger PK, Pelham HR. Yeast heat shock factor is an essential DNA-binding protein that exhibits temperature-dependent phosphorylation. Cell. 1988;54:855–864.
    OpenUrlCrossRefPubMed
  46. 46.↵
    Jedlicka P, Mortin MA, Wu C. Multiple functions of Drosophila heat shock transcription factor in vivo. EMBO J. 1997;16:2452–2462.
    OpenUrlAbstract
  47. 47.↵
    Nakai A, Kawazoe Y, Tanabe M, Nagata K, Morimoto RI. The DNA-binding properties of two heat shock factors, HSF1 and HSF3, are induced in the avian erythroblast cell line HD6. Mol Cell Biol. 1995;15:5268–5278.
    OpenUrlAbstract/FREE Full Text
  48. 48.↵
    Scharf KD, Rose S, Zott W, Schoffl F, Nover L, Schoff F. Three tomato genes code for heat stress transcription factors with a region of remarkable homology to the DNA-binding domain of the yeast HSF [published erratum appears in EMBO J. 1991;10:1026]. EMBO J. 1990;9:4495–4501.
    OpenUrl
  49. 49.↵
    Sarge KD, Zimarino V, Holm K, Wu C, Morimoto RI. Cloning and characterization of two mouse heat shock factors with distinct inducible and constitutive DNA-binding ability. Genes Dev. 1991;5:1902–1911.
    OpenUrlAbstract/FREE Full Text
  50. 50.↵
    Schuetz TJ, Gallo GJ, Sheldon L, Tempst P, Kingston RE. Isolation of a cDNA for HSF2: evidence for two heat shock factor genes in humans. Proc Natl Acad Sci U S A.. 1991;88:6911–6915.
    OpenUrlAbstract/FREE Full Text
  51. 51.↵
    Rallu M, Loones M, Lallemand Y, Morimoto R, Morange M, Mezger V. Function and regulation of heat shock factor 2 during mouse embryogenesis. Proc Natl Acad Sci U S A.. 1997;94:2392–2397.
    OpenUrlAbstract/FREE Full Text
  52. 52.↵
    Knauf U, Newton EM, Kyriakis J, Kingston RE. Repression of human heat shock factor 1 activity at control temperature by phosphorylation. Genes Dev. 1996;10:2782–2793.
    OpenUrlAbstract/FREE Full Text
  53. 53.↵
    Kim J, Nueda A, Meng YH, Dynan WS, Mivechi NF. Analysis of the phosphorylation of human heat shock transcription factor-1 by MAP kinase family members. J Cell Biochem. 1997;67:43–54.
    OpenUrlCrossRefPubMed
  54. 54.↵
    Abravaya K, Myers MP, Murphy SP, Morimoto RI. The human heat shock protein hsp70 interacts with HSF, the transcription factor that regulates heat shock gene expression. Genes Dev. 1992;6:1153–1164.
    OpenUrlAbstract/FREE Full Text
  55. 55.↵
    Rabindran S, Wisniewski J, Li L, Li G, Wu C. Interaction between heat shock factor 70 and hsp70 is insufficient to suppress induction of DNA-binding activity in vivo. Mol Cell Biol. 1994;14:6552–6560.
    OpenUrlAbstract/FREE Full Text
  56. 56.↵
    Lis J, Wu C. Protein traffic on the heat shock promoter: parking, stalling, and trucking along. Cell. 1993;74:1–4.
    OpenUrlCrossRefPubMed
  57. 57.↵
    Benjamin IJ, Kroger B, Williams RS. Activation of the heat shock transcription factor by hypoxia in mammalian cells. Proc Natl Acad Sci U S A.. 1990;87:6263–6267.
    OpenUrlAbstract/FREE Full Text
  58. 58.↵
    Benjamin IJ, Horie S, Greenberg ML, Alpern RJ, Williams RS. Induction of stress proteins in cultured myogenic cells: molecular signals for the activation of heat shock transcription factor during ischemia. J Clin Invest. 1992;89:1685–1689.
  59. 59.↵
    Ananthan J, Goldberg AL, Voellmy R. Abnormal proteins serve as eukaryotic stress signals and trigger the activation of heat shock genes. Science. 1986;232:522–524.
    OpenUrlAbstract/FREE Full Text
  60. 60.↵
    Zhu W, Roma P, Pirillo A, Pellegatta F, Catapano AL. Human endothelial cells exposed to oxidized LDL express hsp70 only when proliferating. Arterioscler Thromb Vasc Biol. 1996;16:1104–1111.
    OpenUrlAbstract/FREE Full Text
  61. 61.↵
    Xu Q, Hu Y, Kleindienst R, Wick G. Nitric oxide induces heat-shock protein 70 expression in vascular smooth muscle cells via activation of heat shock factor 1. J Clin Invest. 1997;100:1089–1097.
    OpenUrlCrossRefPubMed
  62. 62.↵
    Xiao H, Lis JT. Germline transformation used to define key features of heat-shock response elements. Science. 1988;239:1139–1142.
    OpenUrlAbstract/FREE Full Text
  63. 63.↵
    Amin J, Ananthan J, Voellmy R. Key features of heat shock regulatory elements. Mol Cell Biol. 1988;8:3761–3769.
    OpenUrlAbstract/FREE Full Text
  64. 64.↵
    Ciocca DR, Fuqua SA, Lock-Lim S, Toft DO, Welch WJ, McGuire WL. Response of human breast cancer cells to heat shock and chemotherapeutic drugs. Cancer Res. 1992;52:3648–3654.
    OpenUrlAbstract/FREE Full Text
  65. 65.↵
    Mehta HB, Popovich BK, Dillmann WH. Ischemia induces changes in the level of mRNAs coding for stress protein 71 and creatine kinase M. Circ Res. 1988;63:512–517.
    OpenUrlAbstract/FREE Full Text
  66. 66.↵
    Knowlton AA, Brecher P, Apstein CS. Rapid expression of heat shock protein in the rabbit after brief cardiac ischemia. J Clin Invest. 1991;87:139–147.
  67. 67.↵
    Yellon DM, Alkhulaifi AM, Browne EE, Pugsley WB. Ischaemic preconditioning limits infarct size in the rat heart. Cardiovasc Res. 1992;26:983–987.
    OpenUrlAbstract/FREE Full Text
  68. 68.↵
    Donnelly TJ, Sievers RE, Vissern FL, Welch WJ, Wolfe CL. Heat shock protein induction in rat hearts: a role for improved myocardial salvage after ischemia and reperfusion? Circulation. 1992;85:769–778.
    OpenUrlAbstract/FREE Full Text
  69. 69.↵
    Currie RW, Tanguay RM, Kingma JG Jr. Heat-shock response and limitation of tissue necrosis during occlusion/reperfusion in rabbit hearts [see comments]. Circulation. 1993;87:963–971.
    OpenUrlAbstract/FREE Full Text
  70. 70.↵
    Hutter MM, Sievers RE, Barbosa V, Wolfe CL. Heat-shock protein induction in rat hearts: a direct correlation between the amount of heat-shock protein induced and the degree of myocardial protection. Circulation. 1994;89:355–360.
    OpenUrlAbstract/FREE Full Text
  71. 71.↵
    Williams RS, Thomas JA, Fina M, German Z, Benjamin IJ. Human heat shock protein 70 (hsp70) protects murine cells from injury during metabolic stress. J Clin Invest. 1993;92:503–508.
  72. 72.↵
    Mestril R, Chi SH, Sayen MR, O’Reilly K, Dillmann WH. Expression of inducible stress protein 70 in rat heart myogenic cells confers protection against simulated ischemia-induced injury. J Clin Invest. 1994;93:759–767.
  73. 73.↵
    Hutter JJ, Mestril R, Tam EK, Sievers RE, Dillmann WH, Wolfe CL. Overexpression of heat shock protein 72 in transgenic mice decreases infarct size in vivo. Circulation. 1996;94:1408–1411.
    OpenUrlAbstract/FREE Full Text
  74. 74.↵
    Martin JL, Mestril R, Hilal-Dandan R, Brunton LL, Dillmann WH. Small heat shock proteins and protection against ischemic injury in cardiac myocytes. Circulation. 1997;96:4343–4348.
    OpenUrlAbstract/FREE Full Text
  75. 75.↵
    Hightower LE, Sadis SE, Takenaka IM. Interactions of vertebrate hsc70 and hsp70 with unfolded proteins and peptides. In: Morimoto RI, Tissieres A, Georgopoulos C, eds. The Biology of Heat Shock Proteins and Molecular Chaperones. Cold Spring Harbor, NY: Cold Spring Harbor Press; 1994.
  76. 76.↵
    Ellis J. Proteins as molecular chaperones. Nature. 1987;328:378–379.
    OpenUrlCrossRefPubMed
  77. 77.↵
    Freeman BC, Myers MP, Schumacher R, Morimoto RI. Identification of a regulatory motif in Hsp70 that affects ATPase activity, substrate binding and interaction with HDJ-1. EMBO J. 1995;14:2281–2292.
    OpenUrlPubMed
  78. 78.↵
    Chiang HL, Terlecky SR, Plant CP, Dice JF. A role for a 70-kilodalton heat shock protein in lysosomal degradation of intracellular proteins. Science. 1989;246:382–385.
    OpenUrlAbstract/FREE Full Text
  79. 79.↵
    Tiefenbrunn AJ, Sobel BE. Timing of coronary recanalization: paradigms, paradoxes, and pertinence. Circulation. 1992;85:2311–2315.
    OpenUrlFREE Full Text
  80. 80.↵
    Rogers WJ, Bowlby LJ, Chandra NC, French WJ, Gore JM, Lambrew CT, Rubison RM, Tiefenbrunn AJ, Weaver WD. Treatment of myocardial infarction in the United States (1990 to 1993): observations from the National Registry of Myocardial Infarction. Circulation. 1994;90:2103–2114.
    OpenUrlAbstract/FREE Full Text
  81. 81.↵
    Jennings RB, Hawkins HK, Lowe JE, Hill ML, Klotman S, Reimer KA. Relation between high energy phosphate and lethal injury in myocardial ischemia in the dog. Am J Pathol. 1978;92:187–214.
    OpenUrlPubMed
  82. 82.↵
    Liu X, Engelman RM, Moraru II, Rousou JA, Flack JE III, Deaton DW, Maulik N, Das DK. Heat shock: a new approach for myocardial preservation in cardiac surgery. Circulation. 1992;86(suppl II):II-358–II-363.
  83. 83.↵
    Hearse DJ. Reperfusion of the ischemic myocardium. J Mol Cell Cardiol. 1977;9:605–616.
    OpenUrlCrossRefPubMed
  84. 84.↵
    Sohal RS, Agarwal A, Agarwal S, Orr WC. Simultaneous overexpression of copper- and zinc-containing superoxide dismutase and catalase retards age-related oxidative damage and increases metabolic potential in Drosophila melanogaster. J Biol Chem. 1995;270:15671–15674.
    OpenUrlAbstract/FREE Full Text
  85. 85.↵
    Chan PH, Epstein CJ, Li Y, Huang TT, Carlson E, Kinouchi H, Yang G, Kamii H, Mikawa S, Kondo T, et al. Transgenic mice and knockout mutants in the study of oxidative stress in brain injury. J Neurotrauma. 1995;12:815–824.
    OpenUrlCrossRefPubMed
  86. 86.↵
    Kondo T, Sharp FR, Honkaniemi J, Mikawa S, Epstein CJ, Chan PH. DNA fragmentation and prolonged expression of c-fos, c-jun, and hsp70 in kainic acid-induced neuronal cell death in transgenic mice overexpressing human CuZn-superoxide dismutase. J Cereb Blood Flow Metab. 1997;17:241–256.
    OpenUrlCrossRefPubMed
  87. 87.↵
    Braunwald E, Kloner RA. The stunned myocardium: prolonged, postischemic ventricular dysfunction. Circulation. 1982;66:1146–1149.
    OpenUrlAbstract/FREE Full Text
  88. 88.↵
    Bolli R. Oxygen-derived free radicals and myocardial reperfusion injury: an overview. Cardiovasc Drugs Ther. 1991;2:249–268.
  89. 89.↵
    Bolli R. Myocardial “stunning” in man. Circulation. 1992;86:1671–1691.
    OpenUrlFREE Full Text
  90. 90.↵
    Marban E. Myocardial stunning and hibernation: the physiology behind the colloquialisms. Circulation. 1991;83:681–688.
    OpenUrlFREE Full Text
  91. 91.↵
    Tanaka M, Richard VJ, Murry CE, Jennings RB, Reimer KA. Superoxide dismutase plus catalase therapy delays neither cell death nor the loss of the TTC reaction in experimental myocardial infarction in dogs. J Mol Cell Cardiol. 1993;25:367–378.
    OpenUrlCrossRefPubMed
  92. 92.↵
    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.
    OpenUrlCrossRefPubMed
  93. 93.↵
    Pryor WA. Free radicals in autoxidation and in aging. In: Armstrong D, Sohal RS, Cutler RG, Slater TF, eds. Free Radicals in Molecular Biology, Aging, and Disease. New York, NY: Raven Press Publishers; 1984:13–41.
  94. 94.↵
    Karmazyn M, Mailer K, Currie RW. Acquisition and decay of heat-shock-enhanced postischemic ventricular recovery. Am J Physiol. 1990;259:H424–H431.
    OpenUrlAbstract/FREE Full Text
  95. 95.↵
    Mocanu MM, Steare SE, Evans MC, Nugent JH, Yellon DM. Heat stress attenuates free radical release in the isolated perfused rat heart. Free Radic Biol Med. 1993;15:459–463.
    OpenUrlCrossRefPubMed
  96. 96.↵
    Tavaria M, Gabriele T, Kola I, Anderson RL. A hitchhiker’s guide to the human Hsp70 family. Cell Stress Chaperones. 1996;1:23–28.
    OpenUrlCrossRefPubMed
  97. 97.↵
    Beckmann R, Mizzen L, Welch W. Interaction of Hsp 70 with newly synthesized proteins: implications for protein folding and assembly. Science. 1990;248:850–854.
    OpenUrlAbstract/FREE Full Text
  98. 98.↵
    Flynn G, Pohl J, Flocco M, Rothman J. Peptide-binding specificity of the molecular chaperone BiP. Nature. 1991;353:726–730.
    OpenUrlCrossRefPubMed
  99. 99.↵
    Blond-Elguindi S, Cwirla SE, Dower WJ, Lipshutz RJ, Sprang SR, Sambrook JF, Gething MJ. Affinity panning of a library of peptides displayed on bacteriophages reveals the binding specificity of BiP. Cell. 1993;75:717–728.
    OpenUrlCrossRefPubMed
  100. 100.↵
    Flaherty KM, McKay DB, Kabsch W, Holmes KC. Similarity of the three-dimensional structures of actin and the ATPase fragment of a 70-kDa heat shock cognate protein. Proc Natl Acad Sci U S A.. 1991;88:5041–5045.
    OpenUrlAbstract/FREE Full Text
  101. 101.↵
    Feder JH, Rossi JM, Solomon J, Solomon N, Lindquist S. The consequences of expressing hsp70 in Drosophila cells at normal temperatures. Genes Dev. 1992;6:1402–1413.
    OpenUrlAbstract/FREE Full Text
  102. 102.↵
    James P, Pfund C, Craig EA. Functional specificity among Hsp70 molecular chaperones. Science. 1997;275:387–389.
    OpenUrlAbstract/FREE Full Text
  103. 103.↵
    Lai B, Chin N, Stanek A, Keh W, Lanks K. Quantitation and intracellular localization of the 85K heat shock protein by using monoclonal and polyclonal antibodies. Mol Cell Biol. 1984;4:2802–2810.
    OpenUrlAbstract/FREE Full Text
  104. 104.↵
    Denis M, Gustafsson J. The Mr approximately 90,000 heat shock protein: an important modulator of ligand and DNA-binding properties of the glucocorticoid receptor. Cancer Res. 1989;49:2275s–2281s.
    OpenUrlAbstract/FREE Full Text
  105. 105.↵
    Sabbah M, Radanyi C, Redeuilh G, Balieu E. The 90 kDA heat-shock protein (hsp90) modulates the binding of the oestrogen receptor to its cognate DNA. Biochem J. 1996;314:205–213.
  106. 106.↵
    Pratt W. The role of heat shock proteins in regulating the function, folding, and trafficking of the glucocorticoid receptor. J Biol Chem. 1993;268:21455–21458.
    OpenUrlFREE Full Text
  107. 107.↵
    Borkovich KA, Farrelly FW, Finkelstein DB, Taulien J, Lindquist S. hsp82 is an essential protein that is required in higher concentrations for growth of cells at higher temperatures. Mol Cell Biol. 1989;9:3919–3930.
    OpenUrlAbstract/FREE Full Text
  108. 108.↵
    Cruse I, Maines MD. Evidence suggesting that the two forms of heme oxygenase are products of different genes. J Biol Chem. 1988;263:3348–3353.
    OpenUrlAbstract/FREE Full Text
  109. 109.↵
    Ewing JF, Maines MD. Rapid induction of heme oxygenase 1 mRNA and protein by hyperthermia in rat brain: heme oxygenase 2 is not a heat shock protein. Proc Natl Acad Sci U S A.. 1991;88:5364–5368.
    OpenUrlAbstract/FREE Full Text
  110. 110.↵
    McCoubrey WK Jr, Huang TJ, Maines MD. Isolation and characterization of a cDNA from the rat brain that encodes hemoprotein heme oxygenase-3. Eur J Biochem. 1997;247:725–732.
    OpenUrlPubMed
  111. 111.↵
    Abraham NG, Pinto A, Levere RD, Mullane K. Identification of heme oxygenase and cytochrome P-450 in the rabbit heart. J Mol Cell Cardiol. 1987;19:73–81.
    OpenUrlCrossRefPubMed
  112. 112.↵
    Maines MD. Heme oxygenase: function, multiplicity, regulatory mechanisms, and clinical applications. FASEB J. 1988;2:2557–2568.
    OpenUrlAbstract
  113. 113.↵
    Stamler JS, Singel DJ, Loscalzo J. Biochemistry of nitric oxide and its redox-activated forms. Science. 1992;258:1898–1902.
    OpenUrlAbstract/FREE Full Text
  114. 114.↵
    Christodoulides N, Durante W, Kroll MH, Schafer AI. Vascular smooth muscle cell heme oxygenases generate guanylyl cyclase-stimulatory carbon monoxide. Circulation. 1995;91:2306–2309.
    OpenUrlAbstract/FREE Full Text
  115. 115.↵
    Wagner CT, Durante W, Christodoulides N, Hellums JD, Schafer AI. Hemodynamic forces induce the expression of heme oxygenase in cultured vascular smooth muscle cells. J Clin Invest. 1997;100:589–596.
    OpenUrlCrossRefPubMed
  116. 116.↵
    Durante W, Kroll MH, Christodoulides N, Peyton KJ, Schafer AI. Nitric oxide induces heme oxygenase-1 gene expression and carbon monoxide production in vascular smooth muscle cells. Circ Res. 1997;80:557–564.
    OpenUrlAbstract/FREE Full Text
  117. 117.↵
    Ishizaka N, Griendling KK. Heme oxygenase-1 is regulated by angiotensin II in rat vascular smooth muscle cells. Hypertension. 1997;29:790–795.
    OpenUrlAbstract/FREE Full Text
  118. 118.↵
    Ishizaka N, de Leon H, Laursen JB, Fukui T, Wilcox JN, De Keulenaer G, Griendling KK, Alexander RW. Angiotensin II–induced hypertension increases heme oxygenase-1 expression in rat aorta. Circulation. 1997;96:1923–1929.
    OpenUrlAbstract/FREE Full Text
  119. 119.↵
    Shibahara S, Muller RM, Taguchi H. Transcriptional control of rat heme oxygenase by heat shock. J Biol Chem. 1987;262:12889–12892.
    OpenUrlAbstract/FREE Full Text
  120. 120.↵
    Muller RM, Taguchi H, Shibahara S. Nucleotide sequence and organization of the rat heme oxygenase gene. J Biol Chem. 1987;262:6795–6802.
    OpenUrlAbstract/FREE Full Text
  121. 121.↵
    Lee PJ, Jiang BH, Chin BY, Iyer NV, Alam J, Semenza GL, Choi AM. Hypoxia-inducible factor-1 mediates transcriptional activation of the heme oxygenase-1 gene in response to hypoxia. J Biol Chem. 1997;272:5375–5381.
    OpenUrlAbstract/FREE Full Text
  122. 122.↵
    Guillemin K, Krasnow MA. The hypoxic response: huffing and HIFing. Cell. 1997;89:9–12.
    OpenUrlCrossRefPubMed
  123. 123.↵
    Lee PJ, Alam J, Wiegand GW, Choi AM. Overexpression of heme oxygenase-1 in human pulmonary epithelial cells results in cell growth arrest and increased resistance to hyperoxia. Proc Natl Acad Sci U S A.. 1996;93:10393–10398.
    OpenUrlAbstract/FREE Full Text
  124. 124.↵
    Motterlini R, Foresti R, Intaglietta M, Winslow RM. NO-mediated activation of heme oxygenase: endogenous cytoprotection against oxidative stress to endothelium. Am J Physiol. 1996;270:H107–H114.
    OpenUrlAbstract/FREE Full Text
  125. 125.↵
    Wong HR, Wispe JR. The stress response and the lung. Am J Physiol. 1997;273:L1–L9.
    OpenUrlAbstract/FREE Full Text
  126. 126.↵
    Miron T, Vancompernolle K, Vandekerckhove J, Wilchek M, Geiger B. A 25-kD inhibitor of actin polymerization is a low molecular mass heat shock protein. J Cell Biol. 1991;114:255–261.
    OpenUrlAbstract/FREE Full Text
  127. 127.↵
    Gaestel M, Schroder W, Benndorf R, Lippmann C, Buchner K, Hucho F, Erdmann VA, Bielka H. Identification of the phosphorylation sites of the murine small heat shock protein hsp25. J Biol Chem. 1991;266:14721–14724.
    OpenUrlAbstract/FREE Full Text
  128. 128.↵
    Landry J, Lambert H, Zhou M, Lavoie JN, Hickey E, Weber LA, Anderson CW. Human HSP27 is phosphorylated at serines 78 and 82 by heat shock and mitogen-activated kinases that recognize the same amino acid motif as S6 kinase II. J Biol Chem. 1992;267:794–803.
    OpenUrlAbstract/FREE Full Text
  129. 129.↵
    Huot J, Houle F, Spitz DR, Landry J. HSP27 phosphorylation-mediated resistance against actin fragmentation and cell death induced by oxidative stress. Cancer Res. 1996;56:273–279.
    OpenUrlAbstract/FREE Full Text
  130. 130.↵
    Kyriakis JM, Avruch J. Sounding the alarm: protein kinase cascades activated by stress and inflammation. J Biol Chem. 1996;271:24313–24316.
    OpenUrlFREE Full Text
  131. 131.↵
    Bogoyevitch MA, Gillespie-Brown J, Ketterman AJ, Fuller SJ, Ben-Levy R, Ashworth A, Marshall CJ, Sugden PH. Stimulation of the stress-activated mitogen-activated protein kinase subfamilies in perfused heart: p38/RK mitogen-activated protein kinases and c-Jun N-terminal kinases are activated by ischemia/reperfusion. Circ Res. 1996;79:162–173.
    OpenUrlAbstract/FREE Full Text
  132. 132.↵
    Rouse J, Cohen P, Trigon S, Morange M, Alonso-Llamarazes A, Zamanillo D, Hunt T, Nebreda AR. A novel kinase cascade triggered by stress and heat shock that stimulates MAPKAP kinase-2 and phosphorylation of heat shock proteins. Cell. 1994;78:1027–1037.
    OpenUrlCrossRefPubMed
  133. 133.↵
    Rousseau S, Houle F, Landry J, Huot J. p38 MAP kinase activation by vascular endothelial growth factor mediates actin reorganization and cell migration in human endothelial cells. Oncogene. 1997;15:2169–2177.
    OpenUrlCrossRefPubMed
  134. 134.↵
    Huot J, Houle F, Marceau F, Landry J. Oxidative stress–induced actin reorganization mediated by the p38 mitogen-activated protein kinase/heat shock protein 27 pathway in vascular endothelial cells. Circ Res. 1997;80:383–392.
    OpenUrlAbstract/FREE Full Text
  135. 135.↵
    Lutsch G, Vetter R, Offhauss U, Wieske M, Grone HJ, Klemenz R, Schimke I, Stahl J, Benndorf R. Abundance and location of the small heat shock proteins HSP25 and alphaB-crystallin in rat and human heart. Circulation. 1997;96:3466–3476.
    OpenUrlAbstract/FREE Full Text
  136. 136.↵
    Ingolia TD, Craig EA. Four small Drosophila heat shock proteins are related to each other and to mammalian alpha-crystallin. Proc Natl Acad Sci U S A.. 1982;79:2360–2364.
    OpenUrlAbstract/FREE Full Text
  137. 137.↵
    Klemenz R, Frohli E, Steiger RH, Schafer R, Aoyama A. Alpha B-crystallin is a small heat shock protein. Proc Natl Acad Sci U S A.. 1991;88:3652–3656.
    OpenUrlAbstract/FREE Full Text
  138. 138.↵
    de Jong WW, Leunissen JA, Voorter CE. Evolution of the alpha-crystallin/small heat-shock protein family. Mol Biol Evol. 1993;10:103–126.
    OpenUrlAbstract
  139. 139.↵
    Jakob U, Gaestel M, Engel K, Buchner J. Small heat shock proteins are molecular chaperones. J Biol Chem. 1993;268:1517–1520.
    OpenUrlAbstract/FREE Full Text
  140. 140.↵
    Kato K, Shinohara H, Kurobe N, Inaguma Y, Shimizu K, Ohshima K. Tissue distribution and developmental profiles of immunoreactive alpha B crystallin in the rat determined with a sensitive immunoassay system. Biochim Biophys Acta. 1991;1074:201–208.
    OpenUrlPubMed
  141. 141.↵
    Leach IH, Tsang ML, Church RJ, Lowe J. Alpha-B crystallin in the normal human myocardium and cardiac conducting system. J Pathol. 1994;173:255–260.
    OpenUrlCrossRefPubMed
  142. 142.↵
    Bennardini F, Wrzosek A, Chiesi M. αB-Crystallin in cardiac tissue: association with actin and desmin filaments. Circ Res. 1992;71:288–294.
    OpenUrlAbstract/FREE Full Text
  143. 143.↵
    Merck KB, Groenen PJ, Voorter CE, de Haard-Hoekman WA, Horwitz J, Bloemendal H, de Jong WW. Structural and functional similarities of bovine alpha-crystallin and mouse small heat-shock protein: a family of chaperones. J Biol Chem. 1993;268:1046–1052.
    OpenUrlAbstract/FREE Full Text
  144. 144.↵
    Longoni S, James P, Chiesi M. Cardiac alpha-crystallin, I: isolation and identification [corrected and republished with original paging, article originally printed in Mol Cell Biochem.. 1990;97:113–20]. Mol Cell Biochem. 1990;99:113–120.
  145. 145.↵
    Haynes JI II, Duncan MK, Piatigorsky J. Spatial and temporal activity of the alpha B-crystallin/small heat shock protein gene promoter in transgenic mice. Dev Dyn. 1996;207:75–88.
    OpenUrlCrossRefPubMed
  146. 146.↵
    Gopal-Srivastava R, Piatigorsky J. The murine alpha B-crystallin/small heat shock protein enhancer: identification of alpha BE-1, alpha BE-2, alpha BE-3, and MRF control elements. Mol Cell Biol. 1993;13:7144–7152.
    OpenUrlAbstract/FREE Full Text
  147. 147.↵
    Olson EN. Regulation of muscle transcription by the MyoD family: the heart of the matter. Circ Res. 1993;72:1–6.
    OpenUrlAbstract/FREE Full Text
  148. 148.↵
    Neufer PD, Benjamin IJ. Differential expression of alpha B-crystallin and hsp27 in skeletal muscle during continuous contractile activity: relationship to myogenic regulatory factors. J Biol Chem. 1996;271:24089–24095.
    OpenUrlAbstract/FREE Full Text
  149. 149.↵
    Mehlen P, Mehlen A, Godet J, Arrigo AP. Hsp27 as a switch between differentiation and apoptosis in murine embryonic stem cells. J Biol Chem. 1997;272:31657–31665.
    OpenUrlAbstract/FREE Full Text
  150. 150.↵
    Benjamin IJ, Shelton J, Garry DJ, Richardson JA. Temporospatial expression of the small HSP/alpha B-crystallin in cardiac and skeletal muscle during mouse development. Dev Dyn. 1997;208:75–84.
    OpenUrlCrossRefPubMed
  151. 151.↵
    Gopal-Srivastava R, Hapnes JI II, Piatigorsky J. Regulation of the murine aB-crystallin/small heat shock protein gene in cardiac muscle. Mol Cell Biol. 1995;15:7081–7090.
    OpenUrlAbstract/FREE Full Text
  152. 152.↵
    Rudnicki MA, Schnegelsberg PN, Stead RH, Braun T, Arnold HH, Jaenisch R. MyoD or Myf-5 is required for the formation of skeletal muscle. Cell. 1993;75:1351–1359.
    OpenUrlCrossRefPubMed
  153. 153.↵
    Srivastava D, Cserjesi P, Olson EN. A subclass of bHLH proteins required for cardiac morphogenesis. Science. 1995;270:1995–1999.
    OpenUrlAbstract/FREE Full Text
  154. 154.↵
    Kato K, Goto S, Inaguma Y, Hasegawa K, Morishita K, Asano T. Purification and characterization of a 20-kDa protein that is highly homologous to alpha B-crystallin. J Biol Chem. 1994;269:15302–15309.
    OpenUrlAbstract/FREE Full Text
  155. 155.↵
    Caspers GJ, Leunissen JA, de Jong WW. The expanding small heat-shock protein family, and structure predictions of the conserved “alpha-crystallin domain.” J Mol Evol. 1995;40:238–248.
    OpenUrlCrossRefPubMed
  156. 156.↵
    Beall AC, Kato K, Goldenring JR, Rasmussen H, Brophy CM. Cyclic nucleotide-dependent vasorelaxation is associated with the phosphorylation of a small heat shock-related protein. J Biol Chem. 1997;272:11283–11287.
    OpenUrlAbstract/FREE Full Text
  157. 157.↵
    Suzuki A, Sugiyama Y, Hayashi Y, Nyu-i N, Yoshida M, Nonaka I, Ishiura S, Arahata K, Ohno S. MKBP, a novel member of the small heat shock protein family, binds and activates the myotonic dystrophy protein kinase. J Cell Biol. 1998;140:1113–1124.
    OpenUrlAbstract/FREE Full Text
  158. 158.↵
    Lee-Yoon D, Easton D, Murawski M, Burd R, Subjeck JR. Identification of a major subfamily of large hsp70-like proteins through the cloning of the mammalian 110-kDa heat shock protein. J Biol Chem. 1995;270:15725–15733.
    OpenUrlAbstract/FREE Full Text
  159. 159.↵
    Yasuda K, Nakai A, Hatayama T, Nagata K. Cloning and expression of murine high molecular mass heat shock proteins, HSP105. J Biol Chem. 1995;270:29718–29723.
    OpenUrlAbstract/FREE Full Text
  160. 160.↵
    Kaneko Y, Nishiyama H, Nonoguchi K, Higashitsuji H, Kishishita M, Fujita J. A novel hsp110-related gene, apg-1, that is abundantly expressed in the testis responds to a low temperature heat shock rather than the traditional elevated temperatures. J Biol Chem. 1997;272:2640–2645.
    OpenUrlAbstract/FREE Full Text
  161. 161.↵
    Kojima R, Randall J, Brenner B, Gullans S. Osmotic stress protein 94 (Osp94): a new member of the Hsp110/SSE gene subfamily. J Biol Chem. 1996;271:12327–12332.
    OpenUrlAbstract/FREE Full Text
  162. 162.↵
    Parsell DA, Kowal AS, Singer MA, Lindquist S. Protein disaggregation mediated by heat-shock protein Hsp104. Nature. 1994;372:475–478.
    OpenUrlCrossRefPubMed
  163. 163.↵
    Rospert S, Looser R, Dubaquie Y, Matouschek A, Glick BS, Schatz G. Hsp60-independent protein folding in the matrix of yeast mitochondria. EMBO J. 1996;15:764–774.
    OpenUrlPubMed
  164. 164.↵
    Weissman JS, Hohl CM, Kovalenko O, Kashi Y, Chen S, Braig K, Saibil HR, Fenton WA, Horwich AL. Mechanism of GroEL action: productive release of polypeptide from a sequestered position under GroES. Cell. 1995;83:577–587.
    OpenUrlCrossRefPubMed
  165. 165.↵
    Frydman J, Nimmesgern E, Erdjument-Bromage H, Wall JS, Tempst P, Hartl FU. Function in protein folding of TRiC, a cytosolic ring complex containing TCP-1 and structurally related subunits. EMBO J. 1992;11:4767–4778.
    OpenUrlPubMed
  166. 166.↵
    Hohfeld J, Minami Y, Hartl F. Hip, a novel cochaperone involved in the eukaryotic Hsc70/Hsp40 reaction cycle. Cell. 1995;83:589–598.
    OpenUrlCrossRefPubMed
  167. 167.↵
    Nishio ML, Ornatsky OI, Craig EE, Hood DA. Mitochondrial biogenesis during pressure overload induced cardiac hypertrophy in adult rats. Can J Physiol Pharmacol. 1995;73:630–637.
    OpenUrlCrossRefPubMed
  168. 168.↵
    Sohal RS, Ku H-H, Agarwal S, Forster MJ, Lal H. Oxidative damage, mitochondrial oxidant generation and antioxidant defenses during aging and in response to food restriction in the mouse. Mech Ageing Dev. 1994;74:121–133.
    OpenUrlCrossRefPubMed
  169. 169.↵
    Benjamin IJ, Williams RS. Expression and function of stress proteins in the ischemic heart. In: Morimoto RI, Tissieres A, Georgopoulos S, eds. The Biology of Heat Shock Proteins and Molecular Chaperones. 2nd ed. Cold Spring Harbor, NY: Cold Spring Harbor Laboratory Press; 1994:533–552.
  170. 170.↵
    Klausner RD, Sitia R. Protein degradation in the endoplasmic reticulum. Cell. 1990;62:611–614.
    OpenUrlCrossRefPubMed
  171. 171.↵
    Medeiros-Neto G, Kim PS, Yoo SE, Vono J, Targovnik HM, Camargo R, Hossain SA, Arvan P. Congenital hypothyroid goiter with deficient thyroglobulin: identification of an endoplasmic reticulum storage disease with induction of molecular chaperones. J Clin Invest. 1996;98:2838–2844.
    OpenUrlCrossRefPubMed
  172. 172.↵
    Lin HY, Masso-Welch P, Di YP, Cai JW, Shen JW, Subjeck JR. The 170-kDa glucose-regulated stress protein is an endoplasmic reticulum protein that binds immunoglobulin. Mol Biol Cell. 1993;4:1109–1119.
    OpenUrlAbstract/FREE Full Text
  173. 173.↵
    Kilgore JL, Musch TI, Ross CR. Regional distribution of HSP70 proteins after myocardial infraction. Basic Res Cardiol. 1996;91:283–288.
    OpenUrlCrossRefPubMed
  174. 174.↵
    Nishizawa J, Nakai A, Higashi T, Tanabe M, Nomoto S, Matsuda K, Ban T, Nagata K. Reperfusion causes significant activation of heat shock transcription factor 1 in ischemic rat heart. Circulation. 1996;94:2185–2192.
    OpenUrlAbstract/FREE Full Text
  175. 175.↵
    Nakai A, Satoh M, Hirayoshi K, Nagata K. Involvement of the stress protein HSP47 in procollagen processing in the endoplasmic reticulum. J Cell Biol. 1992;117:903–914.
    OpenUrlAbstract/FREE Full Text
  176. 176.↵
    Satoh M, Hirayoshi K, Yokota S, Hosokawa N, Nagata K. Intracellular interaction of collagen-specific stress protein HSP47 with newly synthesized procollagen. J Cell Biol. 1996;133:469–483.
    OpenUrlAbstract/FREE Full Text
  177. 177.↵
    Nagata K. Hsp47: a collagen-specific molecular chaperone. Trends Biochem Sci. 1996;21:22–26.
    OpenUrlPubMed
  178. 178.↵
    Weber KT, Anversa P, Armstrong PW, Brilla CG, Burnett JC Jr, Cruickshank JM, Devereux RB, Giles TD, Korsgaard N, Leier CV, et al. Remodeling and reparation of the cardiovascular system. J Am Coll Cardiol. 1992;20:3–16.
    OpenUrlCrossRefPubMed
  179. 179.↵
    Yoshida T, Maulik N, Engelman RM, Ho YS, Magnenat JL, Rousou JA, Flack JE III, Deaton D, Das DK. Glutathione peroxidase knockout mice are susceptible to myocardial ischemia reperfusion injury. Circulation. 1997;96(suppl II):II-216–II-220.
  180. 180.↵
    Benjamin IJ, Jalil JE, Tan LB, Cho K, Weber KT, Clark WA. Isoproterenol-induced myocardial fibrosis in relation to myocyte necrosis. Circ Res. 1989;65:657–670.
    OpenUrlAbstract/FREE Full Text
  181. 181.↵
    Michael LH, Entman ML, Hartley CJ, Youker KA, Zhu J, Hall SR, Hawkins HK, Berens K, Ballantyne CM. Myocardial ischemia and reperfusion: a murine model. Am J Physiol. 1995;269:H2147–H2154.
    OpenUrlAbstract/FREE Full Text
  182. 182.↵
    Sun JZ, Tang XL, Knowlton AA, Park SW, Qiu Y, Bolli R. Late preconditioning against myocardial stunning: an endogenous protective mechanism that confers resistance to postischemic dysfunction 24 h after brief ischemia in conscious pigs. J Clin Invest. 1995;95:388–403.
  183. 183.↵
    Murry CE, Jennings RB, Reimer KA. Preconditioning with ischemia: a delay of lethal cell injury in ischemic myocardium. Circulation. 1986;74:1124–1136.
    OpenUrlAbstract/FREE Full Text
  184. 184.↵
    Yellon DM, Iliodromitis E, Latchman DS, Van Winkle DM, Downey JM, Williams FM, Williams TJ. Whole body heat stress fails to limit infarct size in the reperfused rabbit heart. Cardiovasc Res. 1992;26:342–346.
    OpenUrlAbstract/FREE Full Text
  185. 185.↵
    Downey JM, Cohen MV, Ytrehus K, Liu Y. Cellular mechanisms in ischemic preconditioning: the role of adenosine and protein kinase C. Ann N Y Acad Sci. 1994;723:82–98.
    OpenUrlPubMed
  186. 186.↵
    Heads RJ, Latchman DS, Yellon DM. Differential stress protein mRNA expression during early ischaemic preconditioning in the rabbit heart and its relationship to adenosine receptor function. J Mol Cell Cardiol. 1995;27:2133–2148.
    OpenUrlCrossRefPubMed
  187. 187.↵
    Ganote C, Armstrong S. Ischaemia and myocyte cytoskeleton: review and speculation. Cardiovasc Res. 1993;27:1387–1403.
    OpenUrlFREE Full Text
  188. 188.↵
    Liang P, MacRae TH. Molecular chaperones and the cytoskeleton. J Cell Sci. 1997;110:1431–1440.
    OpenUrlAbstract/FREE Full Text
  189. 189.↵
    Kuzuya T, Hoshida S, Yamashita N, Fuji H, Oe H, Hori M, Kamada T, Tada M. Delayed effects of sublethal ischemia on the acquisition of tolerance to ischemia. Circ Res. 1993;72:1293–1299.
    OpenUrlAbstract/FREE Full Text
  190. 190.↵
    Hoshida S, Kuzuya T, Yamashita N, Oe H, Fuji H, Hori M, Tada M, Kamada T. Brief myocardial ischemia affects free radical generating and scavenging systems in dogs. Heart Vessels. 1993;8:115–120.
    OpenUrlCrossRefPubMed
  191. 191.↵
    Tang X-L, Qiu Y, Park S-W, Sun J-Z, Kalya A, Bolli R. Time course of late preconditioning against myocardial stunning in conscious pigs. Circ Res. 1996;79:424–434.
    OpenUrlAbstract/FREE Full Text
  192. 192.↵
    Yang XM, Baxter GF, Heads RJ, Yellon DM, Downey JM, Cohen MV. Infarct limitation of the second window of protection in a conscious rabbit model. Cardiovasc Res. 1996;31:777–783.
    OpenUrlCrossRefPubMed
  193. 193.↵
    Schwarz ER, Whyte WS, Kloner RA. Ischemic preconditioning. Curr Opin Cardiol. 1997;12:475–481.
    OpenUrlPubMed
  194. 194.↵
    Hoag JB, Qian YZ, Nayeem MA, D’Angelo M, Kukreja RC. ATP-sensitive potassium channel mediates delayed ischemic protection by heat stress in rabbit heart. Am J Physiol. 1997;273:H2458–H2464.
    OpenUrl
  195. 195.↵
    Brooks G, Hearse DJ. Role of protein kinase C in ischemic preconditioning: player or spectator [editorial]? Circ Res. 1996;79:627–630.
  196. 196.↵
    DeMeester S, Buchman T, Qiu Y, Jacob A, Dunnigan K, Hotchkiss R, Karl I, Cobb J. Heat shock induces IκB-α and prevents stress-induced endothelial cell apoptosis. Arch Surg. 1997;132:1283–1287.
    OpenUrlCrossRefPubMed
  197. 197.↵
    Garcia-Bermejo L, Vilaboa N, Perez C, Galan A, De Blas E, Aller P. Modulation of heat-shock protein 70 (HSP70) gene expression by sodium butyrate in U-937 promonocytic cells: relationships with differentiation and apoptosis. Exp Cell Res. 1997;236:268–274.
    OpenUrlCrossRefPubMed
  198. 198.↵
    Mosser D, Caron A, Bourget L, Denis-Larose C, Massie B. Role of the human heat shock protein hsp70 in protection against stress-induced apoptosis. Mol Cell Biol. 1997;17:5317–5327.
    OpenUrlAbstract/FREE Full Text
  199. 199.↵
    Bissonnette RP, Echeverri F, Mahboubi A, Green DR. Apoptotic cell death induced by c-myc is inhibited by bcl-2. Nature. 1992;359:552–554.
    OpenUrlCrossRefPubMed
  200. 200.↵
    Li WX, Chen CH, Ling CC, Li GC. Apoptosis in heat-induced cell killing: the protective role of hsp-70 and the sensitization effect of the c-myc gene. Radiat Res. 1996;145:324–330.
    OpenUrlCrossRefPubMed
  201. 201.↵
    Strasser A, Anderson RL. Bcl-2 and thermotolerance cooperate in cell survival. Cell Growth Differ. 1995;6:799–805.
    OpenUrlAbstract
  202. 202.↵
    Dix DJ, Allen JW, Collins BW, Mori C, Nakamura N, Poorman-Allen P, Goulding EH, Reddy EM. Targeted gene disruption of Hsp70–2 results in failed meiosis, germ cell apoptosis, and male fertility. Proc Natl Acad Sci U S A.. 1996;93:3264–3268.
    OpenUrlAbstract/FREE Full Text
  203. 203.↵
    Gabai V, Meriin A, Mosser D, Caron A, Rits S, Shifrin V, Sherman M. Hsp70 prevents activation of stress kinases. J Biol Chem. 1997;272:18033–18037.
    OpenUrlAbstract/FREE Full Text
  204. 204.↵
    Polla BS, Kantengwa S, Francois D, Salvioli S, Franceschi C, Marsac C, Cossarizza A, Jacquier-Sarlin MR, Polla BS. Mitochondria are selective targets for the protective effects of heat shock against oxidative injury: dual regulation of heat-shock transcription factor (HSF) activation and DNA-binding activity by H2O2: role of thioredoxin. Proc Natl Acad Sci U S A.. 1996;93:6458–6463.
    OpenUrlAbstract/FREE Full Text
  205. 205.↵
    Kohno T, Yamada Y, Hata T, Mori H, Yamamura M, Tomonaga M, Urata Y, Goto S, Kondo T. Relation of oxidative stress and glutathione synthesis to CD95(Fas/APO-1)-mediated apoptosis of adult T cell leukemia cells. J Immunol. 1996;156:4722–4728.
    OpenUrlAbstract
  206. 206.↵
    Mehlen P, Schulze-Osthoff K, Arrigo AP. Small stress proteins as novel regulators of apoptosis: heat shock protein 27 blocks Fas/APO-1- and staurosporine-induced cell death. J Biol Chem. 1996;271:16510–16514.
    OpenUrlAbstract/FREE Full Text
  207. 207.↵
    Kohane DS, Sarzani R, Schwartz JH, Chobanian AV, Brecher P. Stress-induced proteins in aortic smooth muscle cells and aorta of hypertensive rats. Am J Physiol. 1990;258:H1699–H1705.
    OpenUrlAbstract/FREE Full Text
  208. 208.↵
    Xu Q, Li DG, Holbrook NJ, Udelsman R. Acute hypertension induces heat-shock protein 70 gene expression in rat aorta. Circulation. 1995;92:1223–1229.
    OpenUrlAbstract/FREE Full Text
  209. 209.↵
    Patton WF, Erdjument-Bromage H, Marks AR, Tempst P, Taubman MB. Components of the protein synthesis and folding machinery are induced in vascular smooth muscle cells by hypertrophic and hyperplastic agents: identification by comparative protein phenotyping and microsequencing. J Biol Chem. 1995;270:21404–21410.
    OpenUrlAbstract/FREE Full Text
  210. 210.↵
    Locke M, Tanguay RM. Diminished heat shock response in the aged myocardium. Cell Stress Chaperones. 1996;1:251–260.
    OpenUrlCrossRefPubMed
  211. 211.↵
    Sohal RS. Role of mitochondria and oxidative stress in the aging process. In: Beal MF, Howell N, Bodis-Wollner I, eds. Mitochondria and Free Radicals in Neurogenerative Diseases. New York, NY: Wiley-Liss Inc; 1997.
  212. 212.↵
    Robbins J. α-Tropomyosin knockouts: a blow against transcriptional chauvinism. Circ Res. 1998;82:134–136.
    OpenUrlFREE Full Text
  213. 213.↵
    Geisterfer-Lowrance AA, Christe M, Conner DA, Ingwall JS, Schoen FJ, Seidman CE, Seidman JG. A mouse model of familial hypertrophic cardiomyopathy. Science. 1996;272:731–734.
    OpenUrlAbstract/FREE Full Text
  214. 214.↵
    Sullivan TR Jr, Karas RH, Aronovitz M, Faller GT, Ziar JP, Smith JJ, O’Donnell TF Jr, Mendelsohn ME. Estrogen inhibits the response-to-injury in a mouse carotid artery model. J Clin Invest. 1995;96:2482–2488.
  215. 215.↵
    Iafrati MD, Karas RH, Aronovitz M, Kim S, Sullivan TR Jr, Lubahn DB, O’Donnell TF Jr, Korach KS, Mendelsohn ME. Estrogen inhibits the vascular injury response in estrogen receptor alpha-deficient mice. Nat Med. 1997;3:545–548.
    OpenUrlCrossRefPubMed
  216. 216.↵
    Lobo RA, Speroff L. International consensus conference on postmenopausal hormone therapy and the cardiovascular system [editorial]. Fertil Steril. 1994;61:592–595.
    OpenUrlPubMed
  217. 217.↵
    Marchant DJ. Supplemental estrogen replacement. Cancer. 1994;74:512–517.
    OpenUrlPubMed
  218. 218.↵
    Kannel WB, Hjortland MC, McNamara PM, Gordon T. Menopause and risk of cardiovascular disease: the Framingham study. Ann Intern Med. 1976;85:447–452.
  219. 219.↵
    Castelli WP. Epidemiology of coronary heart disease: the Framingham study. Am J Med. 1984;76:4–12.
    OpenUrlCrossRefPubMed
  220. 220.↵
    Kannel WB, Wilson PW. Risk factors that attenuate the female coronary disease advantage. Arch Intern Med. 1995;155:57–61.
    OpenUrlCrossRefPubMed
  221. 221.↵
    Farhat MY, Lavigne MC, Ramwell PW. The vascular protective effects of estrogen. FASEB J. 1996;10:615–624.
    OpenUrlAbstract
  222. 222.↵
    Xu Q, Wick G. The role of heat shock proteins in protection and pathophysiology of the arterial wall. Mol Med Today. 1996;2:372–379.
    OpenUrlPubMed
  223. 223.↵
    Kleindienst R, Schett G, Amberger A, Seitz CS, Michaelis D, Metzler B, Dietrich H, Xu Q, Wick G. Atherosclerosis as an autoimmune condition. Isr J Med Sci. 1995;31:596–599.
    OpenUrlPubMed
  224. 224.↵
    Schett G, Xu Q, Amberger A, Van der Zee R, Recheis H, Willeit J, Wick G. Autoantibodies against heat shock protein 60 mediate endothelial cytotoxicity. J Clin Invest. 1995;96:2569–2577.
  225. 224A.↵
    Krautz GM, Peterson JD, Godsel LM, Krettli AU, Engman DM. Human antibody responses to Trypanosoma cruzi 70-kD heat-shock proteins. Am J Trop Med Hyg. 1998;58:137–143.
    OpenUrlAbstract
  226. 225.↵
    Bush KT, Goldberg AL, Nigam SK. Proteasome inhibition leads to a heat-shock response, induction of endoplasmic reticulum chaperones, and thermotolerance. J Biol Chem. 1997;272:9086–9092.
    OpenUrlAbstract/FREE Full Text
  227. 226.↵
    Gottesfeld JM, Neely L, Trauger JW, Baird EE, Dervan PB. Regulation of gene expression by small molecules. Nature. 1997;387:202–205.
    OpenUrlCrossRefPubMed
  228. 226A.↵
    Vigh L, Literati PN, Horvath I, Torok Z, Balogh G, Glatz A, Kovacs E, Boros I, Ferdinandy P, Farkas B, Jaszlits L, Jednakovits A, Koranyi L, Maresca B. Bimoclomol: a nontoxic, hydroxylamine derivative with stress-protein activity and cytoprotective effects. Nat Med. 1997;3:1150–1154.
    OpenUrlCrossRefPubMed
  229. 227.↵
    Black SC, Lucchesi BR. Heat shock proteins and the ischemic heart: an endogenous protective mechanism [editorial comment]. Circulation. 1993;87:1048–1051.
    OpenUrlFREE Full Text
  230. 228.↵
    Shen AC, Jennings RB. Myocardial calcium and magnesium in acute ischemic injury. Am J Pathol. 1972;67:417–440.
    OpenUrlPubMed
  231. 229.↵
    Jennings RB, Shen AC. Calcium in experimental myocardial ischemia. Recent Adv Stud Cardiac Struct Metab. 1972;1:639–655.
    OpenUrlPubMed
  232. 230.↵
    Dayton WR, Goll DE, Zeece MG, Robson RM, Reville WJ. A Ca2+-activated protease possibly involved in myofibrillar protein turnover: purification from porcine muscle. Biochemistry. 1976;15:2150–2158.
    OpenUrlCrossRefPubMed
  233. 231.↵
    Dayton WR, Schollmeyer JV. Isolation from porcine cardiac muscle of a Ca2+-activated protease that partially degrades myofibrils. J Mol Cell Cardiol. 1980;12:533–551.
    OpenUrlCrossRefPubMed
  234. 232.↵
    Ganote CE, Nayler WG. Contracture and the calcium paradox. J Mol Cell Cardiol. 1985;17:733–745.
    OpenUrlCrossRefPubMed
  235. 233.
    Kilgore KS, Lucchesi BR. Reperfusion injury after myocardial infarction: the role of free radicals and the inflammatory response. Clin Biochem. 1993;26:359–370.
    OpenUrlCrossRefPubMed
  236. 234.↵
    Barraclough R, Ellis RJ. Protein synthesis in chloroplasts, IX: assembly of newly-synthesized large subunits into ribulose bisphosphate carboxylase in isolated intact pea chloroplasts. Biochim Biophys Acta. 1980;608:19–31.
    OpenUrlPubMed
  237. 235.↵
    Ellis RJ. The general concept of molecular chaperones. Philos Trans R Soc Lond B Biol Sci. 1993;339:257–261.
    OpenUrlCrossRef
  238. 236.↵
    Polla BS, Jacquier-Sarlin MR, Kantengwa S, Mariethoz E, Hennet T, Russo-Marie F, Cossarizza A. TNF alpha alters mitochondrial membrane potential in L929 but not in TNF alpha-resistant L929.12 cells: relationship with the expression of stress proteins, annexin 1 and superoxide dismutase activity. Free Radic Res. 1996;25:125–131.
    OpenUrlCrossRefPubMed
  239. 237.↵
    Jennings RB, Murry CE, Steenbergen C Jr, Reimer KA. Development of cell injury in sustained acute ischemia. Circulation. 1990;82(suppl II):II-2–II-12.
  240. 238.↵
    Medina R, Wing SS, Goldberg AL. Increase in levels of polyubiquitin and proteasome mRNA in skeletal muscle during starvation and denervation atrophy. Biochem J. 1995;307:631–637.
  241. 239.↵
    Sherman MY, Goldberg AL. Involvement of molecular chaperones in intracellular protein breakdown. EXS. 1996;77:57–78.
    OpenUrlPubMed
  242. 240.↵
    Cahill CM, Waterman WR, Xie Y, Auron PE, Calderwood SK. Transcriptional repression of the prointerleukin 1beta gene by heat shock factor 1. J Biol Chem. 1996;271:24874–24879.
    OpenUrlAbstract/FREE Full Text
  243. 241.↵
    Jacquier-Sarlin MR, Fuller K, Dinh-Xuan AT, Richard MJ, Polla BS. Protective effects of hsp70 in inflammation. Experientia. 1994;50:1031–1038.
    OpenUrlCrossRefPubMed
  244. 242.↵
    Malyshev I, Manukhina EB, Mikoyan VD, Kubrina LN, Vanin AF. Nitric oxide is involved in heat-induced HSP70 accumulation. FEBS Lett. 1995;370:159–162.
    OpenUrlCrossRefPubMed
  245. 243.↵
    Malyshev I, Malugin AV, Golubeva L, Zenina TA, Manukhina EB, Mikoyan VD, Vanin AF. Nitric oxide donor induces HSP70 accumulation in the heart and in cultured cells. FEBS Lett. 1996;391:21–23.
    OpenUrlCrossRefPubMed
  246. 244.↵
    Chi SH, Mestril R. Stable expression of a human HSP70 gene in a rat myogenic cell line confers protection against endotoxin. Am J Physiol. 1996;270:C1017–C1021.
    OpenUrlAbstract/FREE Full Text
  247. 245.↵
    Wang D, McMillin JB, Bick R, Buja LM. Response of the neonatal rat cardiomyocyte in culture to energy depletion: effects of cytokines, nitric oxide, and heat shock proteins. Lab Invest. 1996;75:809–818.
    OpenUrlPubMed
  248. 246.↵
    Malyshev I, Malugin AV, Manukhina EB, Larionov NP, Malenyuk EB, Malysheva EV, Mikoyan VD, Vanin AF. Is HSP70 involved in nitric oxide-induced protection of the heart? Physiol Res. 1996;45:267–272.
    OpenUrlPubMed
  249. 247.↵
    Prapapanich V, Chen S, Nair S, Rimerman R, Smith D. Molecular cloning of human p48, a transient component of progesterone receptor complexes and an Hsp70-binding protein. Mol Endocrinol. 1996;10:420–431.
    OpenUrlCrossRefPubMed
  250. 248.↵
    Chen S, Prapapanich V, Rimerman RA, Honoré B, DF Smith. Interactions of p60, a mediator of progesterone receptor assembly, with heat shock proteins hsp90 and hsp70. Mol Endocrinol. 1996;10:682–693.
    OpenUrlCrossRefPubMed
  251. 249.↵
    Gross M, Hessefort S. Purification and characterization of a 66-kDa protein from rabbit reticulocyte lysate which promotes the recycling of hsp 70. J Biol Chem. 1996;271:16833–16841.
    OpenUrlAbstract/FREE Full Text
  252. 250.↵
    Takayama S, Bimston DN, Matsuzawa S, Freeman BC, Aime-Sempe C, Xie Z, Morimoto RI, Reed JC. BAG-1 modulates the chaperone activity of Hsp70/Hsc70. EMBO J. 1997;16:4887–4896.
    OpenUrlAbstract
View Abstract

This Issue

Jump to

Article Tools

Share this Article

  • Email
  • Stress (Heat Shock) Proteins
    Ivor J. Benjamin and D. Randy McMillan
    Circulation Research. 1998;83:117-132, originally published July 27, 1998
    https://doi.org/10.1161/01.RES.83.2.117
    Permalink:
    del.icio.us logo Digg logo Reddit logo Twitter logo CiteULike logo Facebook logo Google logo Mendeley logo

Related Articles

Cited By...