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(Circulation Research. 2000;87:731.)
© 2000 American Heart Association, Inc.

Review

Calcineurin and Beyond

Cardiac Hypertrophic Signaling

Jeffery D. Molkentin

From the Department of Pediatrics, University of Cincinnati, Division of Molecular Cardiovascular Biology, Children’s Hospital Medical Center, Cincinnati, Ohio.

Correspondence to Jeffery D. Molkentin, PhD, Division of Molecular Cardiovascular Biology, Children’s Hospital Medical Center, 3333 Burnet Ave, Cincinnati, OH 45229-3039. E-mail molkj0{at}chmcc.org\\ © 2000 American Heart Association, Inc.

	Abstract

Top Abstract Introduction Calcium and Calcineurin... Sufficiency of Calcineurin and... Calcineurin Activation in... Use of CsA and... Targeted Inhibition of... Conserved Role of Calcineurin... Role of NFAT Transcription... Beyond Calcineurin: Integrated... Clinical Implications References

 
Abstract—In response to increased ventricular wall tension or neurohumoral stimuli, the myocardium undergoes an adaptive hypertrophy response that temporarily augments pump function. Although initially beneficial, sustained cardiac hypertrophy can lead to decompensation and cardiomyopathy. Recent studies have focused on characterizing the molecular mechanisms that underlie cardiac hypertrophy. An increasing number of signal transduction pathways have been identified as important regulators of the hypertrophic response, including the low–molecular weight GTPases (Ras, RhoA, and Rac), mitogen-activated protein kinases, protein kinase C, and calcineurin. This review will discuss an emerging body of evidence that implicates the calcium-calmodulin–activated protein phosphatase calcineurin as a physiological regulator of the cardiac hypertrophic response. Although the sufficiency of calcineurin to promote cardiomyocyte hypertrophy in vivo and in vitro is established, its overall necessity as a hypertrophic mediator is currently an area of ongoing debate. The use of the calcineurin-inhibitory agents cyclosporine A and FK506 have suggested a necessary role for calcineurin in many, but not all, animal models of hypertrophy or cardiomyopathy. The evidence implicating a role for calcineurin signaling in the heart will be weighed against a growing body of literature suggesting necessary roles for a diverse array of intracellular signaling pathways, highlighting the multifactorial nature of the hypertrophic program.

Key Words: calcineurin • cardiac hypertrophy • transcription • heart failure • signaling

	Introduction

Top Abstract Introduction Calcium and Calcineurin... Sufficiency of Calcineurin and... Calcineurin Activation in... Use of CsA and... Targeted Inhibition of... Conserved Role of Calcineurin... Role of NFAT Transcription... Beyond Calcineurin: Integrated... Clinical Implications References

 
Cardiac hypertrophy is defined as an increase in heart size resulting from an increase in cardiomyocyte cell volume. The hypertrophic growth of the myocardium is initiated by a wide array of endocrine, paracrine, and autocrine growth factors in response to increased workload, injury, or intrinsic defects in contractile performance. Although it is initially an adaptive response that temporarily augments or maintains cardiac output, sustained cardiac hypertrophy is a leading cause of the development of heart failure and sudden death in humans.^{1 2} To begin to understand the molecular determinants of the hypertrophic response, recent investigation has focused on identifying and characterizing intracellular signal transduction pathways in the heart.

Traditionally, discussion of intracellular signaling has been largely associated with the actions of protein kinases such as the mitogen-activated protein kinases (MAPKs) or the actions of G proteins. However, intracellular protein phosphatases are also important signal transduction factors that regulate growth and stress responses in a wide variety of cell types. One such phosphatase is the calcium-calmodulin–activated protein phosphatase 2B (PP2B), or calcineurin. Calcineurin is a serine-/threonine–specific phosphatase that is uniquely activated by sustained elevation in [Ca²⁺]_i.^{3 4 5} The active calcineurin holoenzyme is composed of a 59- to 63-kDa catalytic subunit referred to as calcineurin A, a 19-kDa calcium binding protein referred to as calcineurin B, and the calcium binding protein calmodulin.^{3 4} Three mammalian calcineurin A genes have been identified (, ß, and ) that share 81% sequence identity across a 350-amino acid stretch that constitutes the catalytic domain (Figure 1). Even more striking, the calcineurin A and Aß genes share 99% amino acid sequence identity between mouse and human species, suggesting tight evolutionary selection. The calcineurin A and Aß gene products are expressed in a relatively ubiquitous and overlapping pattern throughout the body, whereas calcineurin A is expressed in a more restricted pattern that includes the testis.^{6 7 8 9} Both calcineurin A and Aß proteins, but not A, are present in cardiomyocytes.¹⁰

View larger version (102K): [in this window] [in a new window]   Figure 1. Figure 1. Amino acid sequence comparison of the 3 human calcineurin catalytic subunit genes (CnA, CnAß, and CnA). The blue, green, red, and yellow shaded boxes highlight the catalytic, calcineurin B subunit binding, calmodulin binding, and autoinhibitory domains, respectively.

Calcineurin enzymatic activity is uniquely regulated by displacement of the C-terminal autoinhibitory domain within the catalytic subunit in response to calmodulin binding to an adjacent domain (Figure 1). Calcineurin catalytic activity is inhibited by the immunosuppressive drugs cyclosporine A (CsA) and FK506 through complexes with cyclophilins and FKBP12, respectively.^{3 4} The identification of calcineurin as a target for CsA and FK506 suggested a critical role for this phosphatase in the regulation of T-cell reactivity and cytokine gene expression. The mechanism whereby calcineurin promotes T-cell activation and cytokine induction has been largely attributed to the family of transcriptional regulators referred to as nuclear factor of activated T cells (NFAT). Calcineurin directly binds to NFAT transcription factors in the cytoplasm, resulting in their dephosphorylation and subsequent translocation into the nucleus (Figure 2). Five NFAT transcription factors have been identified, of which NFATc1 through NFATc4 are regulated by calcineurin-mediated dephosphorylation, whereas NFATc5 is constitutively nuclear and not subject to calcineurin regulation.^{11 12}

View larger version (23K): [in this window] [in a new window]   Figure 2. Figure 2. The mechanism of calcineurin-NFAT signaling was first established in T cells. Activation of the T-cell receptor (TCR) promotes increased [Ca2+]i, which saturates calmodulin, resulting in calcineurin activation and subsequent dephosphorylation of NFAT transcription factors. Dephosphorylated NFAT translocates to the nucleus, where it interacts with the promoters of cytokine genes. Immunosuppressive drugs CsA and FK506 complex with immunophilin proteins, which subsequently bind and inhibit calcineurin. T-cell activation also utilizes MAPK (JNK) activation to promote transcriptional activation through activator protein-1 (AP-1), which synergizes with NFAT factors to promote inducible gene expression.

	Calcium and Calcineurin Signaling in the Heart

Top Abstract Introduction Calcium and Calcineurin... Sufficiency of Calcineurin and... Calcineurin Activation in... Use of CsA and... Targeted Inhibition of... Conserved Role of Calcineurin... Role of NFAT Transcription... Beyond Calcineurin: Integrated... Clinical Implications References

 
Although calcium is the fundamental regulator of actin-myosin crossbridge interaction and contraction, it has also been implicated as an inducer of cardiac hypertrophy in response to neurohumoral stimulation, stretch, and pacing.^{13 14 15 16} Many studies have identified alterations in calcium handling in the failed myocardium such that the amplitude of the intracellular calcium transient is decreased and prolonged.¹⁷ Such studies have suggested the hypothesis that alterations in intracellular calcium handling progressively exacerbate a hypertrophic or cardiomyopathic phenotype, in part, through sustained activation of calcium-sensitive signal transduction pathways. The recent identification of calcineurin as a potential hypertrophic regulatory factor supports such a hypothesis.

	Sufficiency of Calcineurin and NFAT to Induce Cardiac Hypertrophy

Top Abstract Introduction Calcium and Calcineurin... Sufficiency of Calcineurin and... Calcineurin Activation in... Use of CsA and... Targeted Inhibition of... Conserved Role of Calcineurin... Role of NFAT Transcription... Beyond Calcineurin: Integrated... Clinical Implications References

 
Calcineurin was originally proposed as a hypertrophic signaling factor based on the identification of NFATc4 as a GATA4 interacting factor in the heart.¹⁸ To characterize the potential involvement of calcineurin in cardiac hypertrophy, an activated truncation mutant of calcineurin was overexpressed in the hearts of transgenic mice.¹⁸ Eleven separate transgenic lines were generated that each demonstrated a profound hypertrophic response (2- to 3-fold increase in heart size) that rapidly progressed to dilated heart failure within 2 to 3 months (Figure 3). Such data implicated calcineurin as a sufficient inducer of the hypertrophic response and as a potential causative factor associated with the transition to decompensation and heart failure. In vitro, infection of cultured neonatal cardiomyocytes with a calcineurin-expressing adenovirus also induced a hypertrophic response, supporting the sufficiency of calcineurin as a hypertrophic mediator.¹⁹

View larger version (91K): [in this window] [in a new window]   Figure 3. Figure 3. Histological analysis demonstrates the profound cardiac hypertrophy response that characterizes the calcineurin transgenic mouse. Top, Hematoxylin and eosin–stained histological sections from a calcineurin transgenic and a wild-type heart at 2 months of age. Bottom, Wheat germ agglutinin (WGA)-TRITC–stained histological sections show the significant increase in myofibrillar cross-sectional area from a calcineurin transgenic heart.

That NFAT transcription factors act downstream of calcineurin in the heart was suggested by the observation that transgenic mice expressing a constitutively nuclear NFATc4 protein (N-terminal truncation) also developed profound hypertrophy within 2 to 3 months of age.¹⁸ However, overexpression of full-length (cytoplasmic) NFATc4 did not produce detectable hypertrophy, suggesting a critical role for calcineurin-mediated activation of NFAT proteins in the heart.¹⁸ Although these studies have demonstrated a sufficiency for calcineurin and NFAT transcription factors as mediators of the cardiac hypertrophic response, a number of questions remain. The requirement of calcineurin and NFAT as endogenous regulators of physiological stress responses in the heart remains largely unproven and an active area of investigation. In addition, the degree to which NFAT factors are required to mediate the hypertrophic effects of calcineurin in the heart remains unresolved (see Role of NFAT Transcription Factors in the Heart, below).

	Calcineurin Activation in Cardiac Hypertrophy

Top Abstract Introduction Calcium and Calcineurin... Sufficiency of Calcineurin and... Calcineurin Activation in... Use of CsA and... Targeted Inhibition of... Conserved Role of Calcineurin... Role of NFAT Transcription... Beyond Calcineurin: Integrated... Clinical Implications References

 
Treatment of cultured neonatal cardiomyocytes with the calcineurin-inhibitory agent CsA was reported to attenuate agonist-induced hypertrophy in vitro.¹⁸ This initial observation suggested that calcineurin is likely activated in cultured cardiomyocytes in response to agonist stimulation. Accordingly, agonist stimulation (phenylephrine, angiotensin II, and 1% FBS) significantly increased calcineurin enzymatic activity in cultured cardiomyocytes, which was associated with an increase in both calcineurin Aß mRNA and protein levels.¹⁰ The observed increase in calcineurin Aß protein in association with myocyte hypertrophy suggests a secondary mechanism (apart from calcium) whereby calcineurin activity can be regulated in the heart. Endothelin-1–stimulated hypertrophy of cultured cardiomyocytes also induced a significant (3-fold) increase in calcineurin activity, although protein levels were not examined.²⁰ In addition, electrical pacing-induced hypertrophy of cultured cardiomyocytes was inhibited by CsA, further implicating calcineurin as a regulator of cardiomyocyte hypertrophy in vitro.²¹ Collectively, these studies demonstrated that calcineurin enzymatic activity was upregulated in cultured cardiomyocytes in association with the hypertrophic response.

Activation of calcineurin in response to pathophysiological stress in vivo remains more controversial. Calcineurin enzymatic activity was upregulated by 2-fold in hearts from juvenile tropomodulin transgenic mice, a model of dilated heart failure.²² This increase was later shown to be associated with a 3-fold increase in total calcineurin A protein content in the heart.²³ Similarly, pressure-overload hypertrophy in aortic-banded rats and exercise-induced cardiac hypertrophy in the rat were each associated with increased calcineurin enzymatic activity in the heart.^{24 25 26 27} In contrast, one group reported no change in cardiac calcineurin activity in response to pressure-overload stimulation,²⁸ whereas another group reported decreases in calcineurin activity.²⁹

The disparate reports discussed above suggest that either differences exist between experimental animal models with respect to calcineurin activation or, more likely, quantification of calcineurin phosphatase activity from tissue or cell lysates is problematic. Experimentally, calcineurin enzymatic activity is determined by monitoring the release of free phosphate (radioactively or chemically) from a phosphorylated substrate such as the RII peptide from whole-cell or tissue protein extracts. Because multiple phosphatases are present in cell extracts, parallel reactions are required in which calcineurin activity is specifically inhibited with the autoinhibitory peptide domain. The resultant activity is then calculated as the difference between the blocked and unblocked states.²⁴ A mixture of phosphatase inhibitors is required to reduce background phosphatase activity and enhance sensitivity, a necessary strategy that also has the effect of partially inhibiting calcineurin activity (okadaic acid). An additional consideration relates to the lability of calcineurin due to oxidation of the Fe-Zn active center, which underscores the observation that calcineurin is 10 to 20 times more active in situ compared with purified protein extracts.³⁰

Despite technical concerns surrounding the calcineurin activity assay, a more important consideration is the relevant information that such an assay gives and its inherent limitations. Even if the in vitro assay is properly performed, it is only an indirect measure of activity and, as such, is inadequate for assessing calcineurin activity in vivo. The calcineurin phosphatase assay measures peak activity in the presence of saturating levels of calmodulin and hence probably only reflects the content of calcineurin available for activation. Given these concerns, it can be argued that a simple Western blot for calcineurin A protein might suffice. Indeed, we have observed that increased enzymatic activity in the heart is often associated with a secondary increase in calcineurin A protein levels.^{22 23 24}

	Use of CsA and FK506 as Calcineurin-Inhibitory Agents in the Heart

Top Abstract Introduction Calcium and Calcineurin... Sufficiency of Calcineurin and... Calcineurin Activation in... Use of CsA and... Targeted Inhibition of... Conserved Role of Calcineurin... Role of NFAT Transcription... Beyond Calcineurin: Integrated... Clinical Implications References

 
Although CsA has been reported to attenuate agonist-induced cardiomyocyte hypertrophy in vitro,^{18 19 20 21} its effectiveness in vivo is problematic. CsA and FK506 each prevented the phenotypic manifestations of hypertrophic and dilated cardiomyopathy in 3 separate transgenic mouse models of intrinsic heart disease.²² In the same report, CsA administration to aortic-banded rats over 6 days prevented the induction of cardiac hypertrophy (Table).²² Although these results suggested new theoretical strategies for treating certain forms of human heart disease, enthusiasm was tempered by the known side effects of CsA and FK506 in humans (see Clinical Implications section, below). Furthermore, 4 subsequent studies concluded that calcineurin inhibitors did not significantly block pressure-overload hypertrophy in either aortic-banded mice or rats, suggesting that CsA and FK506 might not be effective antihypertrophic agents (Table).^{29 30 31 32} However, 6 reports demonstrated a partial or complete inhibition of load-induced cardiac hypertrophy with CsA or FK506 in aortic-banded rats or mice (Table).^{28 29 31 32} In addition, CsA prevented exercise-induced cardiac hypertrophy in the rat,²⁶ attenuated hypertrophy and histopathology in renin and angiotensin transgenic rats,³⁵ attenuated myocardial infarction–induced cardiac hypertrophy in the rat,³⁶ and reduced cardiac hypertrophy in activated Gq transgenic mice.³⁷ In contrast, CsA did not prevent cardiac hypertrophy due to hypertension in the spontaneously hypertensive rat.²⁸ Whereas most pharmacologic studies support a role for calcineurin in the hypertrophic response, the negative accounts may reflect factors such as drug dosage, differences in the surgical preparations, sex, age, or animal strain. For example, the drug dosages that have been used to date vary between 5 and 40 mg/kg of CsA injected either once or twice a day for periods of time between 6 days and 5 weeks.

View this table: [in this window] [in a new window]   Table 1. Summary of Animal Models of Cardiac Hypertrophy Treated With CsA and FK506

Although technical details might certainly underlie some of the conflicting data discussed above, an alternative consideration is the degree to which specific animal models require/utilize a calcineurin-dependent signaling pathway or other hypertrophic signaling pathways. For example, 2 transgenic mouse models of hypertrophic cardiomyopathy have been reported that are resistant to CsA treatment. Transgenic mice overexpressing a mutated retinoid X receptor- or constitutively nuclear NFATc4 in the heart develop cardiac hypertrophy that is insensitive to calcineurin inhibition.^{22 23} In addition, CsA did not block hypertrophy in ascending aortic-banded juvenile mice, a model of gradual onset pressure overload during postnatal development.²⁹ Taken together, these observations underscore the multifactorial nature of the cardiac hypertrophic response and suggest calcineurin-independent pathways for regulating myocyte reactivity.

	Targeted Inhibition of Calcineurin Attenuates Cardiomyocyte Hypertrophy

Top Abstract Introduction Calcium and Calcineurin... Sufficiency of Calcineurin and... Calcineurin Activation in... Use of CsA and... Targeted Inhibition of... Conserved Role of Calcineurin... Role of NFAT Transcription... Beyond Calcineurin: Integrated... Clinical Implications References

 
Another aspect of controversy surrounding CsA and FK506 studies in animal models of hypertrophy pertains to drug specificity. CsA and FK506 each affect multiple intracellular targets besides calcineurin, suggesting alternative mechanisms whereby such drugs might attenuate the hypertrophic response.^{38 39 40} To address the issue of specificity, an alternate approach using the noncompetitive calcineurin-inhibitory domains from the calcineurin-interacting proteins Cain/Cabin-1 and A-kinase anchoring protein 79 (AKAP79) were used.^{41 42 43} Adenovirus expressing the calcineurin-inhibitory domains of Cain or AKAP inhibited calcineurin activity and attenuated phenylephrine- and angiotensin II–induced hypertrophy in cultured cardiomyocytes.¹⁰ The inhibition of hypertrophy by Cain and AKAP adenoviral infection was similar to the inhibition observed with CsA and FK506, suggesting calcineurin as the determinative factor.¹⁰ Calcineurin activity is also negatively regulated by the inhibitory proteins MCIP1 and MCIP2 (DSCR1 and ZAKI-4), which are each highly expressed in the heart and skeletal muscle.^{44 45} It will be interesting to generate and characterize transgenic mice expressing these various calcineurin-inhibitory proteins in the heart to more specifically evaluate the importance of calcineurin as a regulator of cardiac hypertrophy in vivo. Alternatively, targeted disruption of the calcineurin A and/or Aß genes might also provide important genetic evidence confirming or disputing calcineurin as a necessary regulator of cardiac hypertrophy in vivo.Indeed, both calcineurin A and Aß knockout mice are viable, which should permit a final, definitive analysis of the role of calcineurin in the hypertrophic response in the near future. However, because the viability of double-null calcineurin A and Aß mice is uncertain, transgenic dominant-negative–based approaches might still be of significant value.

	Conserved Role of Calcineurin and NFAT in Skeletal Muscle Hypertrophy

Top Abstract Introduction Calcium and Calcineurin... Sufficiency of Calcineurin and... Calcineurin Activation in... Use of CsA and... Targeted Inhibition of... Conserved Role of Calcineurin... Role of NFAT Transcription... Beyond Calcineurin: Integrated... Clinical Implications References

 
A number of recent reports have implicated calcineurin and NFAT in the differentiation and hypertrophy of skeletal muscle, suggesting a conservation in the regulatory program that controls striated muscle cell growth. Specifically, calcineurin promoted skeletal muscle myoblast hypertrophy downstream of an IGF-1–dependent signaling pathway.^{46 47} CsA treatment also blocked the growth response of cultured human myoblasts, attenuated muscle regeneration in response to acute injury in vivo,⁴⁸ and prevented skeletal muscle hypertrophy in response to muscle overloading.⁴⁹ Adenovirus-mediated gene transfer of activated calcineurin in cultured C2C12 and Sol8 myoblasts potentiated their growth, whereas inhibition of calcineurin with Cain or AKAP inhibitory domains attenuated myocyte growth.⁵⁰ NFATc1, NFATc2, and NFATc3 have all been implicated as downstream effectors of calcineurin in the regulation of myoblast differentiation or subsequent hypertrophy in cultured skeletal muscle cells.^{47 48 50} Collectively, these studies suggest a conservation in the regulatory program that controls striated muscle cell hypertrophy through a calcineurin- and NFAT-dependent pathway.

	Role of NFAT Transcription Factors in the Heart

Top Abstract Introduction Calcium and Calcineurin... Sufficiency of Calcineurin and... Calcineurin Activation in... Use of CsA and... Targeted Inhibition of... Conserved Role of Calcineurin... Role of NFAT Transcription... Beyond Calcineurin: Integrated... Clinical Implications References

 
Whereas NFAT transcription factors are important downstream effectors of calcineurin in T cells, neurons, and skeletal muscle myoblasts, we must also consider the alternative hypothesis that calcineurin regulates the cardiac hypertrophic response independently of NFAT factors. Indeed, calcineurin also regulates activity of the transcriptional regulatory factors nuclear factor-B, Elk-1, and myocyte enhancer factor-2 (MEF-2).^{40 51 52 53 54 55} That MEF-2 might be an important hypertrophic transcription factor was recently suggested by the observation that transgenic mice expressing a dominant-negative MEF-2 factor in the heart presented with diminished developmental hypertrophic growth.⁵⁶ As a final consideration, it has been difficult to directly demonstrate endogenous NFAT nuclear translocation in response to hypertrophic agonists in cardiac myocytes. Such a description in the literature may be lacking for technical reasons related to low NFAT protein concentration and/or the lack of reliable antibodies. To ultimately resolve the contribution of NFAT transcription factors as downstream mediators of calcineurin in the heart, it will be necessary to evaluate the ability of NFAT knockout mice to mount a hypertrophic response.

However, analysis of mRNA distribution in mammals has demonstrated that all 5 NFAT genes are expressed in the heart, suggesting that gene-targeting approaches in the mouse will be complicated by redundancy issues.^{12 57 58 59} Despite this concern, single or combinatorial knockout strategies might still implicate NFAT factors as calcineurin effectors in the heart. Accordingly, NFATc4- and NFATc3-null mice are viable and should permit such an evaluation in the near future. Alternatively, NFAT-specific dominant-negative approaches in transgenic mice might also provide significant insights, similar to strategies used in T cells.⁶⁰

Calcineurin may also regulate the cardiac hypertrophic response in coordination with other intracellular signal transduction pathways. Indeed, calcineurin promotes c-Jun N-terminal kinase (JNK), extracellular signal–regulated kinase (ERK), and protein kinase C (PKC) and activation in cardiac myocytes.⁶¹ This observation is consistent with reports in T cells in which calcineurin interconnects (cross talks) with PKC and MAPK signaling pathways in the regulation of cytokine gene expression.^{62 63} However, the mechanisms whereby a phosphatase (calcineurin) might promote the activation of kinases such as JNK and PKC in either T cells or cardiac myocytes is uncertain. A working hypothesis is that calcineurin initiates a primary transcriptional response through NFAT, Elk-1, nuclear factor-B, or MEF-2 factors to set in motion autocrine regulatory mechanisms (angiotensin II or endothelin-1 release) that promote re-entrant signaling through G protein–coupled receptors and receptor tyrosine kinases leading to the secondary activation of PKC and MAPK factors. However, we cannot rule out the possibility that calcineurin might regulate one or more cytoplasmic regulatory factors to indirectly promote PKC and MAPK activation. For example, calcineurin, PKC, and PKA all share a common cytoplasmic docking protein, AKAP79, which suggests a mechanism whereby multiple signaling pathways are coordinately regulated by localization to common cofactors.⁶⁴

	Beyond Calcineurin: Integrated Signaling Networks

Top Abstract Introduction Calcium and Calcineurin... Sufficiency of Calcineurin and... Calcineurin Activation in... Use of CsA and... Targeted Inhibition of... Conserved Role of Calcineurin... Role of NFAT Transcription... Beyond Calcineurin: Integrated... Clinical Implications References

 
In T cells, calcineurin functions in concert with MAPK and PKC signaling pathways to regulate cytokine gene expression and ultimately the immune response itself. Accordingly, gene knockout approaches in the mouse have demonstrated that calcineurin A, PKC, and JNK are each required for productive T-cell reactivity in vivo, suggesting that multiple intracellular signaling pathways are necessary for orchestrating the immune response.^{65 66 67} This paradigm likely extends to cardiac myocytes given the emerging literature that demonstrates a necessary role for diverse intracellular regulatory factors in the hypertrophic response. For example, transgenic mice expressing a dominant-negative G protein in the heart failed to undergo hypertrophy in response to pressure overload.⁶⁸ Similarly, expression of RGS4, a GTPase-activating protein, in the hearts of transgenic mice attenuated pressure-overload hypertrophy, supporting a critical role for G proteins as transducers of hypertrophic stimuli.⁶⁹ Adenovirus-mediated gene transfer of a dominant-negative SEK1 factor (MAPK-kinase-4) blocked the hypertrophic response of aortic-banded rats, suggesting a critical role for MAPK factors in vivo.⁷⁰ Cardiac-restricted deletion of the gp130 receptor in mice profoundly affected the pressure-overload response, implicating an important role for gp130 in cardiac homeostasis.⁷¹ Lastly, fibroblast growth factor 2 knockout mice and AT₂ knockout mice each demonstrated a dramatic reduction in cardiac hypertrophy induced by acute aortic banding.^{72 73} In vitro, several studies have demonstrated necessary roles for signaling factors such as Ras, Raf-1, rac-1, p38, MAP/ERK kinase 1, focal adhesion kinase, and calcineurin in mediating aspects of cardiomyocyte hypertrophy.^{10 74 75 76 77 78 79 80 81}

The above-mentioned studies underscore the multifactorial nature of the cardiac hypertrophic response and suggest a great deal of molecular heterogeneity in the process referred to as cardiac hypertrophy. These studies suggest a model of reactive signaling in the heart whereby certain central pathways are absolutely necessary for the initiation and maintenance of a balanced hypertrophy response, similar to the complexity of signaling involved in T-cell reactivity and cytokine production. In addition, many central regulatory pathways likely interconnect or cross talk with one another in the orchestration of the hypertrophic response. For example, pharmacological inhibition of calcineurin is associated with inhibition of PKC, PKC, and JNK p54 in the heart.⁶¹ Such cross talk might occur through direct molecular interconnections or indirectly through autocrine release of peptide growth factors leading to re-entrant signaling at the cell membrane.

	Clinical Implications

Top Abstract Introduction Calcium and Calcineurin... Sufficiency of Calcineurin and... Calcineurin Activation in... Use of CsA and... Targeted Inhibition of... Conserved Role of Calcineurin... Role of NFAT Transcription... Beyond Calcineurin: Integrated... Clinical Implications References

 
Although calcineurin-inhibitory drugs can attenuate cardiac hypertrophy in some rodent models of pressure overload, their usefulness in humans is doubtful. Both CsA and FK506 have a number of side effects in humans, including nephrogenic and neurogenic toxicity as well as immunosuppression.⁸² Indeed, chronic CsA therapy in human transplant patients induces renal toxicity leading to hypertension and secondary cardiac hypertrophy.⁸³ This observation suggests that CsA is actually associated with cardiac hypertrophy in humans (albeit secondary) when given at immunosuppressive doses. To inhibit cardiac hypertrophy in animals, a 10-fold higher dose of CsA is used than is commonly administered in human immunosuppressive regimens.⁸⁴ Such dosing could be related to higher calcineurin protein content in cardiomyocytes relative to T and B cells or to differences in tissue accessibility. In any event, because a large number of humans develop renal failure and hypertension on the lower dosage, CsA is effectively eliminated as a treatment for cardiac hypertrophy in humans. It is possible, however, that future cardiac-specific methods of inhibiting calcineurin activity will be developed and of potential benefit.

	Acknowledgments

 

This work was supported by NIH Grants HL69562, HL-62927, and HL52318 and by the Pew Charitable Trust Foundation. I would like to thank Drs Katherine Yutzey and Jeffrey Robbins for critical evaluation of this manuscript.

Received August 14, 2000; revision received September 12, 2000; accepted September 15, 2000.

	References

Top Abstract Introduction Calcium and Calcineurin... Sufficiency of Calcineurin and... Calcineurin Activation in... Use of CsA and... Targeted Inhibition of... Conserved Role of Calcineurin... Role of NFAT Transcription... Beyond Calcineurin: Integrated... Clinical Implications References

 
1. Levy D, Garrison RJ, Savage DD, Kannel WB, Castelli WP. Prognostic implications of echocardiographically determined left ventricular mass in the Framingham Heart Study. N Engl J Med. 1990;322:1561–1566.[Abstract]

2. Ho KK, Levy D, Kannel WB, Pinsky JL. The epidemiology of heart failure: the Framingham Study. J Am Coll Cardiol. 1993;22:6–13.[Medline] [Order article via Infotrieve]

3. Crabtree GR. Generic signals and specific outcomes: signaling through Ca²⁺, calcineurin, and NF-AT. Cell. 1999;96:611–614.[Medline] [Order article via Infotrieve]

4. Klee CB, Ren H, Wang X. Regulation of the calmodulin-stimulated protein phosphatase, calcineurin. J Biol Chem. 1998;273:13367–13370.[Free Full Text]

5. Dolmetsch RE, Lewis RS, Goodnow CC, Healy JI. Differential activation of transcription factors induced by Ca²⁺ response amplitude and duration. Nature. 1997;386:855–858.[Medline] [Order article via Infotrieve]

6. Takaishi T, Saito N, Kuno T, Tanaka C. Differential distribution of the mRNA encoding two isoforms of the catalytic subunit of calcineurin in the rat brain. Biochem Biophys Res Commun. 1991;174:393–398.[Medline] [Order article via Infotrieve]

7. Buttini M, Limonta S, Luyten M, Boddeke H. Distribution of calcineurin A isoenzyme mRNAs in rat thymus and kidney. Histochem J. 1995;27:291–299.[Medline] [Order article via Infotrieve]

8. Jiang H, Xiong F, Kong S, Ogawa T, Kobayashi M, Liu JO. Distinct tissue and cellular distribution of two major isoforms of calcineurin. Mol Immunol. 1997;34:663–669.[Medline] [Order article via Infotrieve]

9. Muramatsu T, Giri PR, Higuchi S, Kincaid RL. Molecular cloning of a calmodulin-dependent phosphatase from murine testis: identification of a developmentally expressed nonneural isoenzyme. Proc Natl Acad Sci U S A. 1992;89:529–533.[Abstract/Free Full Text]

10. Taigen T, De Windt LJ, Lim HW, Molkentin JD. Targeted inhibition of calcineurin prevents agonist-induced cardiomyocyte hypertrophy. Proc Natl Acad Sci U S A. 2000;97:1196–1201.[Abstract/Free Full Text]

11. Rao A, Luo C, Hogan PG. Transcription factors of the NFAT family: regulation and function. Annu Rev Immunol. 1997;15:707–747.[Medline] [Order article via Infotrieve]

12. Lopéz-Rodríguez C, Aramburu J, Rakeman AS, Rao A. NFAT5, a constitutively nuclear NFAT protein that does not cooperate with Fos and Jun. Proc Natl Acad Sci U S A. 1999;96:7214–7219.[Abstract/Free Full Text]

13. Marbán E, Kitakaze M, Kusuoka H, Porterfield JK, Yue DT, Chacko VP. Intracellular free calcium concentrations measured with 19F NMR spectroscopy in intact ferret hearts. Proc Natl Acad Sci U S A. 1987;84:6005–6009.[Abstract/Free Full Text]

14. Bustamante JO, Ruknudin A, Sachs F. Stretch-activated channels in heart cells: relevance to cardiac hypertrophy. J Cardiovasc Pharmacol. 1991;17:S110–S113.

15. Perreault CL, Shannon RP, Shen YT, Vatner SF, Morgan JP. Excitation-contraction coupling in isolated myocardium from dogs with compensated left ventricular hypertrophy. Am J Physiol. 1994;266:H2436–H2442.[Abstract/Free Full Text]

16. Eble DM, Qi M, Waldschmidt S, Lucchesi PA, Byron KL, Samarel AM. Contractile activity is required for sarcomeric assembly in phenylephrine-induced cardiac myocyte hypertrophy. Am J Physiol. 1998;274:C1226–C1237.[Abstract/Free Full Text]

17. Balke CW, Shorofsky SR. Alterations in calcium handling in cardiac hypertrophy and heart failure. Cardiovasc Res. 1998;37:290–299.[Abstract/Free Full Text]

18. Molkentin JD, Lu JR, Antos CL, Markham B, Richardson J, Robbins J, Grant SR, Olson EN. A calcineurin-dependent transcriptional pathway for cardiac hypertrophy. Cell. 1998;93:215–228.[Medline] [Order article via Infotrieve]

19. De Windt LJ, Lim HW, Taigen T, Wencker D, Condorelli G, Dorn GW 2nd, Kitsis RN, Molkentin JD. Calcineurin-mediated hypertrophy protects cardiomyocytes from apoptosis in vitro and in vivo: an apoptosis-independent model of dilated heart failure. Circ Res. 2000;86:255–263.[Abstract/Free Full Text]

20. Zhu W, Zou Y, Shiojima I, Kudoh S, Aikawa R, Hayashi D, Mizukami M, Toko H, Shibasaki F, Yazaki Y, Nagai R, Komuro I. Ca²⁺/calmodulin-dependent kinase II and calcineurin play critical roles in endothelin-1-induced cardiomyocyte hypertrophy. J Biol Chem. 2000;275:15239–15245.[Abstract/Free Full Text]

21. Xia Y, McMillin JB, Lewis A, Moore M, Zhu WG, Williams RS, Kellems RE. Electrical stimulation of neonatal cardiac myocytes activates the NFAT3 and GATA4 pathways and up-regulates the adenylosuccinate synthetase 1 gene. J Biol Chem. 2000;275:1855–1863.[Abstract/Free Full Text]

22. Sussman MA, Lim HW, Gude N, Taigen T, Olson EN, Robbins J, Colbert MC, Gualberto A, Wieczorek DF, Molkentin JD. Prevention of cardiac hypertrophy in mice by calcineurin inhibition. Science. 1998;281:1690–1693.[Abstract/Free Full Text]

23. Lim HW, De Windt LJ, Mante J, Kimball TR, Witt SA, Sussman MA, Molkentin JD. Reversal of cardiac hypertrophy in transgenic disease models by calcineurin inhibition. J Mol Cell Cardiol. 2000;32:697–709.[Medline] [Order article via Infotrieve]

24. Lim HW, De Windt LJ, Steinberg L, Taigen T, Witt SA, Kimball TR, Molkentin JD. Calcineurin expression, activation, and function in cardiac pressure-overload hypertrophy. Circulation. 2000;101:2431–2437.[Abstract/Free Full Text]

25. Shimoyama M, Hayashi D, Takimoto E, Zou Y, Oka T, Uozumi H, Kudoh S, Shibasaki F, Yazaki Y, Nagai R, Komuro I. Calcineurin plays a critical role in pressure overload-induced cardiac hypertrophy. Circulation. 1999;100:2449–2454.[Abstract/Free Full Text]

26. Eto Y, Yonekura K, Sonoda M, Arai N, Sata M, Sugiura S, Takenaka K, Gualberto A, Hixon ML, Wagner MW, Aoyagi T. Calcineurin is activated in rat hearts with physiological left ventricular hypertrophy induced by voluntary exercise training. Circulation. 2000;101:2134–2137.[Abstract/Free Full Text]

27. Hayashida W, Kihara Y, Yasaka A, Sasayama S. Cardiac calcineurin during transition from hypertrophy to heart failure in rats. Biochem Biophys Res Commun. 2000;273:347–351.[Medline] [Order article via Infotrieve]

28. Zhang W, Kowal RC, Rusnak F, Sikkink RA, Olson EN, Victor RG. Failure of calcineurin inhibitors to prevent pressure-overload left ventricular hypertrophy in rats. Circ Res. 1999;84:722–728.[Abstract/Free Full Text]

29. Ding B, Price RL, Borg TK, Weinberg EO, Halloran PF, Lorell BH. Pressure overload induces severe hypertrophy in mice treated with cyclosporine, an inhibitor of calcineurin. Circ Res. 1999;84:729–734.[Abstract/Free Full Text]

30. Wang X, Culotta VC, Klee CB. Superoxide dismutase protects calcineurin from inactivation. Nature. 1996;383:434–437.[Medline] [Order article via Infotrieve]

31. Luo Z, Shyu KG, Gualberto A, Walsh K. Calcineurin and cardiac hypertrophy. Nat Med. 1998;10:1092–1093.

32. Müller JG, Nemoto S, Laser M, Carabello BA, Menick DR. Calcineurin inhibition and cardiac hypertrophy. Science. 1998;282:1007. Letter.

33. Meguro T, Hong C, Asai K, Takagi G, McKinsey TA, Olson EN, Vatner SF. Cyclosporine attenuates pressure-overload hypertrophy in mice while enhancing susceptibility to decompensation and heart failure. Circ Res. 1999;84:735–740.[Abstract/Free Full Text]

34. Hill JA, Karimi M, Kutschke W, Davisson RL, Zimmerman K, Wang Z, Kerber RE, Weiss RM. Cardiac hypertrophy is not a required compensatory response to short-term pressure overload. Circulation. 2000;101:2863–2869.[Abstract/Free Full Text]

35. Mervaala E, Muller DN, Park JK, Dechend R, Schmidt F, Fiebeler A, Bieringer M, Breu V, Ganten D, Haller H, Luft FC. Cyclosporin A protects against angiotensin II-induced end-organ damage in double transgenic rats harboring human renin and angiotensinogen genes. Hypertension. 2000;35(1 pt 2):360–366.

36. Øie EB, Reidar OPF, Clausen H, Attramadal. Cyclosporin A inhibits cardiac hypertrophy and enhances cardiac dysfunction during postinfarction failure in rats. Am J Physiol Heart Circ Physiol. 2000;278:2115–2123.

37. Mende U, Kagen A, Cohen A, Aramburu J, Schoen FJ, Neer EJ. Transient cardiac expression of constitutively active Gq leads to hypertrophy and dilated cardiomyopathy by calcineurin-dependent and independent pathways. Proc Natl Acad Sci U S A. 1998;95:13893–13898.[Abstract/Free Full Text]

38. duBell WH, Gaa ST, Lederer WJ, Rogers TB. Independent inhibition of calcineurin and K⁺ currents by the immunosuppressant FK-506 in rat ventricle. Am J Physiol Heart Circ Physiol. 1998;275:2041–2052.

39. Kaibori M, Okumura T, Ito S, Oda M, Inoue T, Kamiyama Y. Inhibition of iNOS induction by FK506, but not by cyclosporine, in rat hepatocytes. Transplant Proc. 1999;31:804–805.[Medline] [Order article via Infotrieve]

40. Meyer S, Kohler NG, Joly A. Cyclosporine A is an uncompetitive inhibitor of proteasome activity and prevents NF-B activation. FEBS Lett. 1997;413:354–358.[Medline] [Order article via Infotrieve]

41. Lai MM, Burnett PE, Wolosker H, Blackshaw S, Snyder SH. Cain, a novel physiologic protein inhibitor of calcineurin. J Biol Chem. 1998;273:18325–18331.[Abstract/Free Full Text]

42. Sun L, Youn HD, Loh C, Stolow M, He W, Liu JO. Cabin 1, a negative regulator for calcineurin signaling in T lymphocytes. Immunity. 1998;8:703–711.[Medline] [Order article via Infotrieve]

43. Coghlan VM, Perrino BA, Howard M, Langeberg LK, Hicks JB, Gallatin WM, Scott JD. Association of protein kinase A and protein phosphatase 2B with a common anchoring protein. Science. 1995;267:108–111.[Abstract/Free Full Text]

44. Rothermel B, Vega RB, Yang J, Wu H, Bassel-Duby R, Williams RS. A protein encoded within the Down syndrome critical region is enriched in striated muscles and inhibits calcineurin signaling. J Biol Chem. 2000;275:8719–8725.[Abstract/Free Full Text]

45. Fuentes JJ, Genesca L, Kingsbury TJ, Cunningham KW, Perez-Riba M, Estivill X, de la Luna S. DSCR1, overexpressed in Down syndrome, is an inhibitor of calcineurin-mediated signaling pathways. Hum Mol Genet. 2000;9:1681–1690.[Abstract/Free Full Text]

46. Semsarian C, Wu M-J, Ju Y-K, Marciniec T, Yeoh T, Allen DG, Harvey RP, Graham RM. Skeletal muscle hypertrophy is mediated by a Ca²⁺-dependent calcineurin signaling pathway. Nature. 1999;400:576–580.[Medline] [Order article via Infotrieve]

47. Musaró A, McCullagh KJA, Naya FJ, Olson EN, Rosenthal N. IGF-1 induces skeletal myocyte hypertrophy through calcineurin in association with GATA-2 and NF-ATc1. Nature. 1999;400:581–585.[Medline] [Order article via Infotrieve]

48. Abbott KL, Friday BB, Thaloor D, Murphy TJ, Pavlath GK. Activation and cellular localization of the cyclosporine A-sensitive transcription factor NF-AT in skeletal muscle. Mol Biol Cell. 1998;9:2905–2916.[Abstract/Free Full Text]

49. Dunn SE, Burns JL, Michel RN. Calcineurin is required for skeletal muscle hypertrophy. J Biol Chem. 1999;274:21908–21912.[Abstract/Free Full Text]

50. Delling U, Tureckova J, Lim HW, De Windt LJ, Rotwein P, Molkentin JD. A calcineurin/NFATc3-dependent pathway regulates skeletal muscle differentiation and slow myosin heavy chain expression. Mol Cell Biol. 2000;20:6600–6611.[Abstract/Free Full Text]

51. Sugimoto T, Stewart S, Guan KL. The calcium-dependent protein phosphatase calcineurin is the major Elk-1 phosphatase. J Biol Chem. 1997;272:29415–29418.[Abstract/Free Full Text]

52. Tian J, Karin M. Stimulation of Elk1 transcriptional activity by mitogen-activated protein kinases is negatively regulated by protein phosphatase 2B (calcineurin). J Biol Chem. 1999;274:15173–15180.[Abstract/Free Full Text]

53. Wu H, Naya FJ, McKinsey TA, Mercer B, Shelton JM, Chin ER, Simard AR, Michel RN, Bassel-Duby R, Olson EN, Williams RS. MEF2 responds to multiple calcium-regulated signals in the control of skeletal muscle fiber-type. EMBO J. 2000;19:1963–1973.[Medline] [Order article via Infotrieve]

54. Mao Z, Wiedmann M. Calcineurin enhances MEF2 DNA binding activity in calcium-dependent survival of cerebellar granule neurons. J Biol Chem. 1999;274:31102–31107.[Abstract/Free Full Text]

55. Blaser F, Ho N, Prywes R, Chatila TA. Calcium-dependent gene expression mediated by MEF2 transcription factors. J Biol Chem. 2000;275:197–209.[Abstract/Free Full Text]

56. Kolodziejczyk SM, Wang L, Balazsi K, DeRepentigny Y, Kothary R, Megeney LA. MEF2 is upregulated during cardiac hypertrophy and is required for normal post-natal growth of the myocardium. Curr Biol. 1999;9:1203–1206.[Medline] [Order article via Infotrieve]

57. Liu J, Koyano-Nakagawa N, Amasaki Y, Saito-Ohara F, Ikeuchi T, Imai S, Takano T, Arai N, Yokota T, Arai K. Calcineurin-dependent nuclear translocation of a murine transcription factor NFATx: molecular cloning and functional characterization. Mol Biol Cell. 1997;8:157–170.[Abstract]

58. Masuda ES, Naito Y, Tokumitsu H, Campbell D, Saito F, Hannum C Arai K, Arai N. NFATx, a novel member of the nuclear factor of activated T cells family that is expressed predominantly in the thymus. Mol Cell Biol. 1995;15:2697–2706.[Abstract]

59. Hoey T, Sun YL, Williamson K, Xu X. Isolation of two new members of the NF-AT gene family and functional characterization of the NF-AT proteins. Immunity. 1995;2:461–472.[Medline] [Order article via Infotrieve]

60. Aramburu J, Yaffe MB, Lopez-Rodriguez C, Cantley LC, Hogan PG, Rao A. Affinity-driven peptide selection of an NFAT inhibitor more selective than cyclosporin A. Science. 1999;285:2129–2133.[Abstract/Free Full Text]

61. De Windt LJ, Lim HW, Haq S, Force T, Molkentin JD. Calcineurin promotes protein kinase C and c-Jun NH2-terminal kinase activation in the heart: evidence of crosstalk between cardiac hypertrophic signaling pathways. J Biol Chem. 2000;275:13571–13579.[Abstract/Free Full Text]

62. Avraham A, Jung S, Samuels Y, Seger R, Ben-Neriah Y, Co-stimulation-dependent activation of a JNK-kinase in T lymphocytes. Eur J Immunol. 1998;28:2320–2330.[Medline] [Order article via Infotrieve]

63. Werlen G, Jacinto E, Xia Y, Karin M. Calcineurin preferentially synergizes with PKC- to activate JNK and IL-2 promoter in T lymphocytes. EMBO J. 1998;17:3101–3111.[Medline] [Order article via Infotrieve]

64. Klauck TM, Faux MC, Labudda K, Langeberg LK, Jaken S, Scott JD. Coordination of three signaling enzymes by AKAP79, a mammalian scaffold protein. Science. 1996;271:1589–1592.[Abstract]

65. Zhang BW, Zimmer G, Chen J, Ladd D, Li E, Alt FW, Wiederrecht G, Cryan J, O’Neill EA, Seidman CE, Abbas AK, Seidman JG. T cell responses in calcineurin A -deficient mice. J Exp Med. 1996;183:413–420.[Abstract/Free Full Text]

66. Sun Z, Arendt CW, Ellmeier W, Schaeffer EM, Sunshine MJ, Gandhi L, Annes J, Petrzilka D, Kupfer A, Schwartzberg PL, Littman DR. PKC- is required for TCR-induced NF-B activation in mature but not immature T lymphocytes. Nature. 2000;404:402–407.[Medline] [Order article via Infotrieve]

67. Dong C, Yang DD, Tournier C, Whitmarsh AJ, Xu J, Davis RJ, Flavell RA. JNK is required for effector T-cell function but not for T-cell activation. Nature. 2000;405:91–94.[Medline] [Order article via Infotrieve]

68. Akhter SA, Luttrell LM, Rockman HA, Iaccarino G, Lefkowitz RJ, Koch WJ. Targeting the receptor-Gq interface to inhibit in vivo pressure overload myocardial hypertrophy. Science. 1998;280:574–577.[Abstract/Free Full Text]

69. Rogers JH, Tamirisa P, Kovacs A, Weinheimer C, Courtois M, Blumer KJ, Kelly DP, Muslin AJ. RGS4 causes increased mortality and reduced cardiac hypertrophy in response to pressure overload. J Clin Invest. 1999;104:567–576.[Medline] [Order article via Infotrieve]

70. Choukroun G, Hajjar R, Fry S, del Monte F, Haq S, Guerrero JL, Picard M Rosenzweig A, Force T. Regulation of cardiac hypertrophy in vivo by the stress-activated protein kinases/c-Jun NH₂-terminal kinases. J Clin Invest. 1999;104:391–398.[Medline] [Order article via Infotrieve]

71. Hirota H, Chen J, Betz UA, Rajewsky K, Gu Y, Ross J Jr, Muller W, Chien KR. Loss of a gp130 cardiac muscle cell survival pathway is a critical event in the onset of heart failure during biomechanical stress. Cell. 1999;97:189–198.[Medline] [Order article via Infotrieve]

72. Schultz JE, Witt SA, Nieman ML, Reiser PJ, Engle SJ, Zhou M, Pawlowski SA, Lorenz JN, Kimball TR, Doetschman T. Fibroblast growth factor-2 mediates pressure-induced hypertrophic response. J Clin Invest. 1999;104:709–719.[Medline] [Order article via Infotrieve]

73. Senbonmatsu T, Ichihara S, Price E Jr, Gaffney FA, Inagami T. Evidence for angiotensin II type 2 receptor-mediated cardiac myocyte enlargement during in vivo pressure overload. J Clin Invest. 2000;106:1–5.

74. Gillespie-Brown J, Fuller SJ, Bogoyevitch MA, Cowley S, Sugden PH. The mitogen-activated protein kinase kinase MEK1 stimulates a pattern of gene expression typical of the hypertrophic phenotype in rat ventricular cardiomyocytes. J Biol Chem. 1995;270:28092–28096.[Abstract/Free Full Text]

75. Zou Y, Komuro I, Yamazaki T, Aikawa R, Kudoh S, Shiojima I, Hiroi Y, Mizumo T, Yazaki Y. Protein kinase C, but not tyrosine kinases or Ras, plays a critical role in angiotensin II-induced activation of Raf-1 kinase and extracellular signal-regulated protein kinases in cardiac myocytes. J Biol Chem. 1996;271:33592–33597.[Abstract/Free Full Text]

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

77. Abdellatif M, Packer SE, Michael LH, Zhang D, Charng MJ, Schneider MD. A Ras-dependent pathway regulates RNA polymerase II phosphorylation in cardiac myocytes: implications for cardiac hypertrophy. Mol Cell Biol. 1998;11:6729–6736.

78. Pracyk JB, Tanaka K, Hegland DD, Kim KS, Sethi R, Rovira II, Blazina DR, Bruder JT, Kovesdi I, Goldschmidt-Clermont PJ, Irani K, Finkel T. A requirement for the rac1 GTPase in the signal transduction pathway leading to cardiac myocyte hypertrophy. J Clin Invest. 1998;102:929–937.[Medline] [Order article via Infotrieve]

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

80. Eble DM, Strait JB, Govindarajan G, Lou J, Byron KL, Samarel AM. Endothelin-induced cardiac myocyte hypertrophy: role for focal adhesion kinase. Am J Physiol Heart Circ Physiol. 2000;278:H1695–H1707.[Abstract/Free Full Text]

81. Ueyama T, Kawashima S, Sakoda T, Rikitake Y, Ishida T, Kawai M, Yamashita T, Ishido S, Hotta H, Yokoyama M. Requirement of activation of the extracellular signal-regulated kinase cascade in myocardial cell hypertrophy. J Mol Cell Cardiol. 2000;32:947–60.[Medline] [Order article via Infotrieve]

82. Haverich A, Costard-Jackle A, Cremer J, Herrmann G, Simon R. Cyclosporin A and transplant coronary disease after heart transplantation: facts and fiction. Transplant Proc. 1994;26:2713–2715.[Medline] [Order article via Infotrieve]

83. Ventura HO, Malik FS, Mehra MR, Stapelton DD, Smart FW. Mechanisms of hypertension in cardiac transplantation and the role of cyclosporine. Curr Opin Cardiol. 1997;12:375–381.[Medline] [Order article via Infotrieve]

84. Batiuk TD, Urmson J, Vincent D, Yatscoff RW, Halloran PF. Quantitating immunosuppression. Transplantation. 1996;61:1618–1624.[Medline] [Order article via Infotrieve]

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				B. J. Wilkins, L. J. De Windt, O. F. Bueno, J. C. Braz, B. J. Glascock, T. F. Kimball, and J. D. Molkentin Targeted Disruption of NFATc3, but Not NFATc4, Reveals an Intrinsic Defect in Calcineurin-Mediated Cardiac Hypertrophic Growth Mol. Cell. Biol., November 1, 2002; 22(21): 7603 - 7613. [Abstract] [Full Text] [PDF]

				B. G. Petrich, X. Gong, D. L. Lerner, X. Wang, J. H. Brown, J. E. Saffitz, and Y. Wang c-Jun N-Terminal Kinase Activation Mediates Downregulation of Connexin43 in Cardiomyocytes Circ. Res., October 4, 2002; 91(7): 640 - 647. [Abstract] [Full Text] [PDF]

				P. K Busk, J. Bartkova, C. C Strom, L. Wulf-Andersen, R. Hinrichsen, T. E.H Christoffersen, L. Latella, J. Bartek, S. Haunso, and S. P Sheikh Involvement of cyclin D activity in left ventricle hypertrophy in vivo and in vitro Cardiovasc Res, October 1, 2002; 56(1): 64 - 75. [Abstract] [Full Text] [PDF]

				Y. Wang, G. W. De Keulenaer, E. O. Weinberg, S. Muangman, A. Gualberto, K. T. Landschulz, T. G. Turi, J. F. Thompson, and R. T. Lee Direct biomechanical induction of endogenous calcineurin inhibitor Down Syndrome Critical Region-1 in cardiac myocytes Am J Physiol Heart Circ Physiol, August 1, 2002; 283(2): H533 - H539. [Abstract] [Full Text] [PDF]

				E. A. Woodcock, B. H. Wang, J. F. Arthur, A. Lennard, S. J. Matkovich, X.-J. Du, J. H. Brown, and R. D. Hannan Inositol Polyphosphate 1-Phosphatase Is a Novel Antihypertrophic Factor J. Biol. Chem., June 14, 2002; 277(25): 22734 - 22742. [Abstract] [Full Text] [PDF]

				S. E. Hardt and J. Sadoshima Glycogen Synthase Kinase-3{beta}: A Novel Regulator of Cardiac Hypertrophy and Development Circ. Res., May 31, 2002; 90(10): 1055 - 1063. [Abstract] [Full Text] [PDF]

				B. J Wilkins and J. D Molkentin Calcineurin and cardiac hypertrophy: Where have we been? Where are we going? J. Physiol., May 15, 2002; 541(1): 1 - 8. [Abstract] [Full Text] [PDF]

				O. F. Bueno, B. J. Wilkins, K. M. Tymitz, B. J. Glascock, T. F. Kimball, J. N. Lorenz, and J. D. Molkentin Impaired cardiac hypertrophic response in Calcineurin Abeta -deficient mice PNAS, April 2, 2002; 99(7): 4586 - 4591. [Abstract] [Full Text] [PDF]

				G. Chu, A. N. Carr, K. B. Young, J.W. Lester, A. Yatani, A. Sanbe, M. C. Colbert, S. M. Schwartz, K. F. Frank, P. D. Lampe, et al. Enhanced myocyte contractility and Ca2+ handling in a calcineurin transgenic model of heart failure Cardiovasc Res, April 1, 2002; 54(1): 105 - 116. [Abstract] [Full Text] [PDF]

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

				M. Mendez and M. C. LaPointe Trophic Effects of the Cyclooxygenase-2 Product Prostaglandin E2 in Cardiac Myocytes Hypertension, February 1, 2002; 39(2): 382 - 388. [Abstract] [Full Text] [PDF]

				C. L. Antos, T. A. McKinsey, N. Frey, W. Kutschke, J. McAnally, J. M. Shelton, J. A. Richardson, J. A. Hill, and E. N. Olson Activated glycogen synthase-3beta suppresses cardiac hypertrophy in vivo PNAS, January 7, 2002; (2002) 231619298. [Abstract] [Full Text] [PDF]

				Z. Wang, W. Kutschke, K. E. Richardson, M. Karimi, and J. A. Hill Electrical Remodeling in Pressure-Overload Cardiac Hypertrophy: Role of Calcineurin Circulation, October 2, 2001; 104(14): 1657 - 1663. [Abstract] [Full Text] [PDF]

				D.-S. Lim, R. Roberts, and A. J. Marian Expression profiling of cardiac genes in human hypertrophic cardiomyopathy: insight into the pathogenesis of phenotypes J. Am. Coll. Cardiol., October 1, 2001; 38(4): 1175 - 1180. [Abstract] [Full Text] [PDF]

				G. W. Dorn II Calcineurin Inhibition in Hypertrophy : Back From the Dead! Circulation, July 3, 2001; 104(1): 9 - 11. [Full Text] [PDF]

				T. E Hebert Signalling in cardiac disease: the molecular deficit at the heart of the problem Cardiovasc Res, April 1, 2001; 50(1): 7 - 9. [Full Text] [PDF]

				H. W. Lim, L. New, J. Han, and J. D. Molkentin Calcineurin Enhances MAPK Phosphatase-1 Expression and p38 MAPK Inactivation in Cardiac Myocytes J. Biol. Chem., May 4, 2001; 276(19): 15913 - 15919. [Abstract] [Full Text] [PDF]

				Z. Wang, B. Nolan, W. Kutschke, and J. A. Hill Na+-Ca2+ Exchanger Remodeling in Pressure Overload Cardiac Hypertrophy J. Biol. Chem., May 18, 2001; 276(21): 17706 - 17711. [Abstract] [Full Text] [PDF]

				O. F. Bueno, B. J. Wilkins, K. M. Tymitz, B. J. Glascock, T. F. Kimball, J. N. Lorenz, and J. D. Molkentin Impaired cardiac hypertrophic response in Calcineurin Abeta -deficient mice PNAS, April 2, 2002; 99(7): 4586 - 4591. [Abstract] [Full Text] [PDF]

				C. L. Antos, T. A. McKinsey, N. Frey, W. Kutschke, J. McAnally, J. M. Shelton, J. A. Richardson, J. A. Hill, and E. N. Olson Activated glycogen synthase-3beta suppresses cardiac hypertrophy in vivo PNAS, January 22, 2002; 99(2): 907 - 912. [Abstract] [Full Text] [PDF]

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