151
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Nakayama H, Bodi I, Maillet M, DeSantiago J, Domeier TL, Mikoshiba K, Lorenz JN, Blatter LA, Bers DM, Molkentin JD. The IP3 receptor regulates cardiac hypertrophy in response to select stimuli. Circ Res 2010; 107:659-66. [PMID: 20616315 DOI: 10.1161/circresaha.110.220038] [Citation(s) in RCA: 134] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
RATIONALE Inositol 1,4,5-trisphosphate (IP(3)) is a second messenger that regulates intracellular Ca(2+) release through IP(3) receptors located in the sarco(endo)plasmic reticulum of cardiac myocytes. Many prohypertrophic G protein-coupled receptor (GPCR) signaling events lead to IP(3) liberation, although its importance in transducing the hypertrophic response has not been established in vivo. OBJECTIVE Here, we generated conditional, heart-specific transgenic mice with both gain- and loss-of-function for IP(3) receptor signaling to examine its hypertrophic growth effects following pathological and physiological stimulation. METHODS AND RESULTS Overexpression of the mouse type-2 IP(3) receptor (IP(3)R2) in the heart generated mild baseline cardiac hypertrophy at 3 months of age. Isolated myocytes from overexpressing lines showed increased Ca(2+) transients and arrhythmias in response to endothelin-1 stimulation. Although low levels of IP(3)R2 overexpression failed to augment/synergize cardiac hypertrophy following 2 weeks of pressure-overload stimulation, such levels did enhance hypertrophy following 2 weeks of isoproterenol infusion, in response to Galphaq overexpression, and/or in response to exercise stimulation. To inhibit IP(3) signaling in vivo, we generated transgenic mice expressing an IP(3) chelating protein (IP(3)-sponge). IP(3)-sponge transgenic mice abrogated cardiac hypertrophy in response to isoproterenol and angiotensin II infusion but not pressure-overload stimulation. Mechanistically, IP(3)R2-enhanced cardiac hypertrophy following isoproterenol infusion was significantly reduced in the calcineurin-Abeta-null background. CONCLUSION These results indicate that IP(3)-mediated Ca(2+) release plays a central role in regulating cardiac hypertrophy downstream of GPCR signaling, in part, through a calcineurin-dependent mechanism.
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Affiliation(s)
- Hiroyuki Nakayama
- Howard Hughes Medical Institute, Cincinnati Children's Hospital Medical Center, 240 Albert Sabin Way, Cincinnati, OH 45229-3039, USA
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152
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Patel A, Sharif-Naeini R, Folgering JRH, Bichet D, Duprat F, Honoré E. Canonical TRP channels and mechanotransduction: from physiology to disease states. Pflugers Arch 2010; 460:571-81. [PMID: 20490539 DOI: 10.1007/s00424-010-0847-8] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2010] [Revised: 05/05/2010] [Accepted: 05/06/2010] [Indexed: 01/03/2023]
Abstract
Mechano-gated ion channels play a key physiological role in cardiac, arterial, and skeletal myocytes. For instance, opening of the non-selective stretch-activated cation channels in smooth muscle cells is involved in the pressure-dependent myogenic constriction of resistance arteries. These channels are also implicated in major pathologies, including cardiac hypertrophy or Duchenne muscular dystrophy. Seminal work in prokaryotes and invertebrates highlighted the role of transient receptor potential (TRP) channels in mechanosensory transduction. In mammals, recent findings have shown that the canonical TRPC1 and TRPC6 channels are key players in muscle mechanotransduction. In the present review, we will focus on the functional properties of TRPC1 and TRPC6 channels, on their mechano-gating, regulation by interacting cytoskeletal and scaffolding proteins, physiological role and implication in associated diseases.
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Affiliation(s)
- Amanda Patel
- IPMC-CNRS, Université de Nice Sophia Antipolis, 660 Route des Lucioles, 06560, Valbonne, France
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153
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Lipskaia L, Ly H, Kawase Y, Hajjar RJ, Lompre AM. Treatment of heart failure by calcium cycling gene therapy. Future Cardiol 2010; 3:413-23. [PMID: 19804232 DOI: 10.2217/14796678.3.4.413] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Heart failure is a major cause of morbidity and mortality in Western countries. While progress in conventional treatment modalities is making steady and incremental gains to reduce this disease burden, there remains a need to explore new and potentially therapeutic approaches. Gene therapy, for example, was initially envisioned as a treatment strategy for inherited monogenic disorders. It is now apparent that gene therapy has broader potential, which also includes acquired polygenic diseases such as heart failure. Advances in the understanding of the molecular basis of conditions such as these, together with the evolution of increasingly efficient gene transfer technology, has placed congestive heart failure within the reach of gene-based therapy.
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Affiliation(s)
- Larissa Lipskaia
- INSERM U621, Université Pierre et Marie Curie-CHU Pitié-Salpétriêre, Paris, France
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154
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Kinoshita H, Kuwahara K, Nishida M, Jian Z, Rong X, Kiyonaka S, Kuwabara Y, Kurose H, Inoue R, Mori Y, Li Y, Nakagawa Y, Usami S, Fujiwara M, Yamada Y, Minami T, Ueshima K, Nakao K. Inhibition of TRPC6 channel activity contributes to the antihypertrophic effects of natriuretic peptides-guanylyl cyclase-A signaling in the heart. Circ Res 2010; 106:1849-60. [PMID: 20448219 DOI: 10.1161/circresaha.109.208314] [Citation(s) in RCA: 117] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Atrial and brain natriuretic peptides (ANP and BNP, respectively) exert antihypertrophic effects in the heart via their common receptor, guanylyl cyclase (GC)-A, which catalyzes the synthesis of cGMP, leading to activation of protein kinase (PK)G. Still, much of the network of molecular mediators via which ANP/BNP-GC-A signaling inhibit cardiac hypertrophy remains to be characterized. OBJECTIVE We investigated the effect of ANP-GC-A signaling on transient receptor potential subfamily C (TRPC)6, a receptor-operated Ca(2+) channel known to positively regulate prohypertrophic calcineurin-nuclear factor of activated T cells (NFAT) signaling. METHODS AND RESULTS In cardiac myocytes, ANP induced phosphorylation of TRPC6 at threonine 69, the PKG phosphorylation site, and significantly inhibited agonist-evoked NFAT activation and Ca(2+) influx, whereas in HEK293 cells, it dramatically inhibited agonist-evoked TRPC6 channel activity. These inhibitory effects of ANP were abolished in the presence of specific PKG inhibitors or by substituting an alanine for threonine 69 in TRPC6. In model mice lacking GC-A, the calcineurin-NFAT pathway is constitutively activated, and BTP2, a selective TRPC channel blocker, significantly attenuated the cardiac hypertrophy otherwise seen. Conversely, overexpression of TRPC6 in mice lacking GC-A exacerbated cardiac hypertrophy. BTP2 also significantly inhibited angiotensin II-induced cardiac hypertrophy in mice. CONCLUSIONS Collectively, these findings suggest that TRPC6 is a critical target of antihypertrophic effects elicited via the cardiac ANP/BNP-GC-A pathway and suggest TRPC6 blockade could be an effective therapeutic strategy for preventing pathological cardiac remodeling.
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Affiliation(s)
- Hideyuki Kinoshita
- Department of Medicine and Clinical Science, Kyoto University Graduated School of Medicine, Kyoto 606-8507, Japan
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155
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TRPC channels are necessary mediators of pathologic cardiac hypertrophy. Proc Natl Acad Sci U S A 2010; 107:7000-5. [PMID: 20351294 DOI: 10.1073/pnas.1001825107] [Citation(s) in RCA: 206] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Pathologic hypertrophy of the heart is regulated through membrane-bound receptors and intracellular signaling pathways that function, in part, by altering Ca(2+) handling and Ca(2+)-dependent signaling effectors. Transient receptor potential canonical (TRPC) channels are important mediators of Ca(2+)-dependent signal transduction that can sense stretch or activation of membrane-bound receptors. Here we generated cardiac-specific transgenic mice that express dominant-negative (dn) TRPC3, dnTRPC6, or dnTRPC4 toward blocking the activity of the TRPC3/6/7 or TRPC1/4/5 subfamily of channels in the heart. Remarkably, all three dn transgenic strategies attenuated the cardiac hypertrophic response following either neuroendocrine agonist infusion or pressure-overload stimulation. dnTRPC transgenic mice also were partially protected from loss of cardiac functional performance following long-term pressure-overload stimulation. Importantly, adult myocytes isolated from hypertrophic WT hearts showed a unique Ca(2+) influx activity under store-depleted conditions that was not observed in myocytes from hypertrophied dnTRPC3, dnTRPC6, or dnTRPC4 hearts. Moreover, dnTRPC4 inhibited the activity of the TRPC3/6/7 subfamily in the heart, suggesting that these two subfamilies function in coordinated complexes. Mechanistically, inhibition of TRPC channels in transgenic mice or in cultured neonatal myocytes significantly reduced activity in the calcineurin-nuclear factor of activated T cells (NFAT), a known Ca(2+)-dependent hypertrophy-inducing pathway. Thus, TRPC channels are necessary mediators of pathologic cardiac hypertrophy, in part through a calcineurin-NFAT signaling pathway.
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156
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Sun YH, Li YQ, Feng SL, Li BX, Pan ZW, Xu CQ, Li TT, Yang BF. Calcium-sensing receptor activation contributed to apoptosis stimulates TRPC6 channel in rat neonatal ventricular myocytes. Biochem Biophys Res Commun 2010; 394:955-61. [PMID: 20307499 DOI: 10.1016/j.bbrc.2010.03.096] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Accepted: 03/16/2010] [Indexed: 02/07/2023]
Abstract
Capacitative calcium entry (CCE) refers to the influx of calcium through plasma membrane channels activated on depletion of endoplasmic sarcoplasmic/reticulum (ER/SR) Ca(2+) stores, which is performed mainly by the transient receptor potential (TRP) channels. TRP channels are expressed in cardiomyocytes. Calcium-sensing receptor (CaR) is also expressed in rat cardiac tissue and plays an important role in mediating cardiomyocyte apoptosis. However, there are no data regarding the link between CaR and TRP channels in rat heart. In this study, in rat neonatal myocytes, by Ca(2+) imaging, we found that the depletion of ER/SR Ca(2+) stores by thapsigargin (TG) elicited a transient rise in cytoplasmic Ca(2+) ([Ca(2+)](i)), followed by sustained increase depending on extracellular Ca(2+). But, TRP channels inhibitor (SKF96365), not L-type channels or the Na(+)/Ca(2+) exchanger inhibitors, inhibited [Ca(2+)](i) relatively high. Then, we found that the stimulation of CaR with its activator gadolinium chloride (GdCl(3)) or by an increased extracellular Ca(2+)([Ca(2+)](o)) increased the concentration of intracelluar Ca(2+), whereas, the sustained elevation of [Ca(2+)](i) was reduced in the presence of SKF96365. Similarly, the duration of [Ca(2+)](i) increase was also shortened in the absence of extracellular Ca(2+). Western blot analysis showed that GdCl(3) increased the expression of TRPC6, which was reversed by SKF96365. Additionally, SKF96365 reduced cardiomyocyte apoptosis induced by GdCl(3). Our results suggested that CCE exhibited in rat neonatal myocytes and CaR activation induced Ca(2+)-permeable cationic channels TRPCs to gate the CCE, for which TRPC6 was one of the most likely candidates. TRPC6 channel was functionally coupled with CaR to enhance the cardiomyocyte apoptosis.
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Affiliation(s)
- Yi-hua Sun
- Department of Clinical Laboratory, The Second Affiliated Hospital of Harbin Medical University, Harbin 150086, China
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157
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Abstract
JPs (junctophilins) contribute to the formation of junctional membrane complexes in muscle cells by physically linking the t-tubule (transverse-tubule) and SR (sarcoplasmic reticulum) membranes. In humans with HCM (hypertrophic cardiomyopathy), mutations in JP2 are linked to altered Ca2+ signalling in cardiomyocytes; however, the effects of these mutations on skeletal muscle function have not been examined. In the present study, we investigated the role of the dominant-negative JP2-S165F mutation (which is associated with human HCM) in skeletal muscle. Consistent with the hypertrophy observed in human cardiac muscle, overexpression of JP2-S165F in primary mouse skeletal myotubes led to a significant increase in myotube diameter and resting cytosolic Ca2+ concentration. Single myotube Ca2+ imaging experiments showed reductions in both the excitation-contraction coupling gain and RyR (ryanodine receptor) 1-mediated Ca2+ release from the SR. Immunoprecipitation assays revealed defects in the PKC (protein kinase C)-mediated phosphorylation of the JP2-S165F mutant protein at Ser165 and in binding of JP2-S165F to the Ca2+ channel TRPC3 (transient receptor potential cation canonical-type channel 3) on the t-tubule membrane. Therefore both the hypertrophy and altered intracellular Ca2+ signalling in the JP2-S165F-expressing skeletal myotubes can be linked to altered phosphorylation of JP2 and/or altered cross-talk among Ca2+ channels on the t-tubule and SR membranes.
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158
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Gronich N, Kumar A, Zhang Y, Efimov IR, Soldatov NM. Molecular remodeling of ion channels, exchangers and pumps in atrial and ventricular myocytes in ischemic cardiomyopathy. Channels (Austin) 2010; 4:101-7. [PMID: 20090424 PMCID: PMC2891309 DOI: 10.4161/chan.4.2.10975] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Existing molecular knowledge base of cardiovascular diseases is rudimentary because of lack of specific attribution to cell type and function. The aim of this study was to investigate cell-specific molecular remodeling in human atrial and ventricular myocytes associated with ischemic cardiomyopathy. Our strategy combines two technological innovations, laser-capture microdissection of identified cardiac cells in selected anatomical regions of the heart and splice microarray of a narrow catalog of the functionally most important genes regulating ion homeostasis. We focused on expression of a principal family of genes coding for ion channels, exchangers and pumps (CE&P genes) that are involved in electrical, mechanical and signaling functions of the heart and constitute the most utilized drug targets. We found that (1) CE&P genes remodel in a cell-specific manner: ischemic cardiomyopathy affected 63 CE&P genes in ventricular myocytes and 12 essentially different genes in atrial myocytes. (2) Only few of the identified CE&P genes were previously linked to human cardiac disfunctions. (3) The ischemia-affected CE&P genes include nuclear chloride channels, adrenoceptors, cyclic nucleotide-gated channels, auxiliary subunits of Na(+), K(+) and Ca(2+) channels, and cell-surface CE&Ps. (4) In both atrial and ventricular myocytes ischemic cardiomyopathy reduced expression of CACNG7 and induced overexpression of FXYD1, the gene crucial for Na(+) and K(+) homeostasis. Thus, our cell-specific molecular profiling defined new landmarks for correct molecular modeling of ischemic cardiomyopathy and development of underlying targeted therapies.
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Affiliation(s)
- Naomi Gronich
- National Institute on Aging; National Institutes of health; Baltimore, MD USA
| | - Azad Kumar
- National Institute on Aging; National Institutes of health; Baltimore, MD USA
| | - Yuwei Zhang
- National Institute on Aging; National Institutes of health; Baltimore, MD USA
| | | | - Nikolai M. Soldatov
- National Institute on Aging; National Institutes of health; Baltimore, MD USA
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159
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KIYONAKA S, KATO K, NISHIDA M, MORI Y. Pharmacological Properties of Novel TRPC Channel Inhibitors. YAKUGAKU ZASSHI 2010; 130:303-11. [DOI: 10.1248/yakushi.130.303] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Shigeki KIYONAKA
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University
| | - Kenta KATO
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University
| | - Motohiro NISHIDA
- Department of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Kyushu University
| | - Yasuo MORI
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University
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160
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Nishida M, Watanabe K, Sato Y, Nakaya M, Kitajima N, Ide T, Inoue R, Kurose H. Phosphorylation of TRPC6 channels at Thr69 is required for anti-hypertrophic effects of phosphodiesterase 5 inhibition. J Biol Chem 2010; 285:13244-53. [PMID: 20177073 DOI: 10.1074/jbc.m109.074104] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Activation of Ca(2+) signaling induced by receptor stimulation and mechanical stress plays a critical role in the development of cardiac hypertrophy. A canonical transient receptor potential protein subfamily member, TRPC6, which is activated by diacylglycerol and mechanical stretch, works as an upstream regulator of the Ca(2+) signaling pathway. Although activation of protein kinase G (PKG) inhibits TRPC6 channel activity and cardiac hypertrophy, respectively, it is unclear whether PKG suppresses cardiac hypertrophy through inhibition of TRPC6. Here, we show that inhibition of cGMP-selective PDE5 (phosphodiesterase 5) suppresses endothelin-1-, diacylglycerol analog-, and mechanical stretch-induced hypertrophy through inhibition of Ca(2+) influx in rat neonatal cardiomyocytes. Inhibition of PDE5 suppressed the increase in frequency of Ca(2+) spikes induced by agonists or mechanical stretch. However, PDE5 inhibition did not suppress the hypertrophic responses induced by high KCl or the activation of protein kinase C, suggesting that PDE5 inhibition suppresses Ca(2+) influx itself or molecule(s) upstream of Ca(2+) influx. PKG activated by PDE5 inhibition phosphorylated TRPC6 proteins at Thr(69) and prevented TRPC6-mediated Ca(2+) influx. Substitution of Ala for Thr(69) in TRPC6 abolished the anti-hypertrophic effects of PDE5 inhibition. In addition, chronic PDE5 inhibition by oral sildenafil treatment actually induced TRPC6 phosphorylation in mouse hearts. Knockdown of RGS2 (regulator of G protein signaling 2) and RGS4, both of which are activated by PKG to reduce G alpha(q)-mediated signaling, did not affect the suppression of receptor-activated Ca(2+) influx by PDE5 inhibition. These results suggest that phosphorylation and functional suppression of TRPC6 underlie prevention of pathological hypertrophy by PDE5 inhibition.
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Affiliation(s)
- Motohiro Nishida
- Department of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Kyushu University, Higashi-ku, Fukuoka 812-8582, Japan
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161
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van Oort RJ, Respress JL, Li N, Reynolds C, De Almeida AC, Skapura DG, De Windt LJ, Wehrens XHT. Accelerated development of pressure overload-induced cardiac hypertrophy and dysfunction in an RyR2-R176Q knockin mouse model. Hypertension 2010; 55:932-8. [PMID: 20157052 DOI: 10.1161/hypertensionaha.109.146449] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In response to chronic hypertension, the heart compensates by hypertrophic growth, which frequently progresses to heart failure. Although intracellular calcium (Ca(2+)) has a central role in hypertrophic signaling pathways, the Ca(2+) source for activating these pathways remains elusive. We hypothesized that pathological sarcoplasmic reticulum Ca(2+) leak through defective cardiac intracellular Ca(2+) release channels/ryanodine receptors (RyR2) accelerates heart failure development by stimulating Ca(2+)-dependent hypertrophic signaling. Mice heterozygous for the gain-of-function mutation R176Q/+ in RyR2 and wild-type mice were subjected to transverse aortic constriction. Cardiac function was significantly lower, and cardiac dimensions were larger at 8 weeks after transverse aortic constriction in R176Q/+ compared with wild-type mice. R176Q/+ mice displayed an enhanced hypertrophic response compared with wild-type mice as assessed by heart weight:body weight ratios and cardiomyocyte cross-sectional areas after transverse aortic constriction. Quantitative PCR revealed increased transcriptional activation of cardiac stress genes in R176Q/+ mice after transverse aortic constriction. Moreover, pressure overload resulted in an increased sarcoplasmic reticulum Ca(2+) leak, associated with higher expression levels of the exon 4 splice form of regulator of calcineurin 1, and a decrease in nuclear factor of activated T-cells phosphorylation in R176Q/+ mice compared with wild-type mice. Taken together, our results suggest that RyR2-dependent sarcoplasmic reticulum Ca(2+) leak activates the prohypertrophic calcineurin/nuclear factor of activated T-cells pathway under conditions of pressure overload.
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Affiliation(s)
- Ralph J van Oort
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, 1 Baylor Plaza, BCM 335, Houston, TX 77030, USA
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162
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Voelkers M, Salz M, Herzog N, Frank D, Dolatabadi N, Frey N, Gude N, Friedrich O, Koch WJ, Katus HA, Sussman MA, Most P. Orai1 and Stim1 regulate normal and hypertrophic growth in cardiomyocytes. J Mol Cell Cardiol 2010; 48:1329-34. [PMID: 20138887 DOI: 10.1016/j.yjmcc.2010.01.020] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2009] [Revised: 01/23/2010] [Accepted: 01/28/2010] [Indexed: 01/19/2023]
Abstract
Cardiac hypertrophy is an independent risk for heart failure (HF) and sudden death. Deciphering signalling pathways dependent on extracellular calcium (Ca(2+)) influx that control normal and pathological cardiac growth may enable identification of novel therapeutic targets. The objective of the present study is to determine the role of the Ca(2+) release-activated Ca(2+) (CRAC) channel Orai1 and stromal interaction molecule 1 (Stim1) in postnatal cardiomyocyte store operated Ca(2+) entry (SOCE) and impact on normal and hypertrophic postnatal cardiomyocyte growth. Employing a combination of siRNA-mediated gene silencing, cultured neonatal rat ventricular cardiomyocytes together with indirect immunofluorescence, epifluorescent Ca(2+) imaging and site-specific protein phosphorylation and real-time mRNA expression analysis, we show for the first time that both Orai1 and Stim1 are present in cardiomyocytes and required for SOCE due to intracellular Ca(2+) store depletion by thapsigargin. Stim1-KD but not Orai1-KD significantly decreased diastolic Ca(2+) levels and caffeine-releasable Ca(2+) from the sarcoplasmic reticulum (SR). Conversely, Orai1-KD but not Stim1-KD significantly diminished basal NRCM cell size, anp and bnp mRNA levels and activity of the calcineurin (CnA) signalling pathway although diminishing both Orai1 and Stim1 proteins similarly attenuated calmodulin kinase II (CamKII) and ERK1/2 activity under basal conditions. Both Orai1- and Stim1-KD completely abrogated phenylephrine (PE) mediated hypertrophic NRCM growth and enhanced natriuretic factor expression by inhibiting G(q)-protein conveyed activation of the CamKII and ERK1/2 signalling pathway. Interestingly, only Orai1-KD but not Stim1-KD prevented Gq-mediated CaN-dependent prohypertrophic signalling. This study shows for the first time that both Orai1 and Stim1 have a key role in cardiomyocyte SOCE regulating both normal and hypertrophic postnatal cardiac growth in vitro.
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Affiliation(s)
- Mirko Voelkers
- Department of Internal Medicine III, Laboratory for Molecular and Translational Cardiology, Division of Cardiology, INF 350, University of Heidelberg, 69120 Heidelberg, Germany.
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163
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Chatham JC, Marchase RB. The role of protein O-linked beta-N-acetylglucosamine in mediating cardiac stress responses. BIOCHIMICA ET BIOPHYSICA ACTA 2010; 1800:57-66. [PMID: 19607882 PMCID: PMC2814923 DOI: 10.1016/j.bbagen.2009.07.004] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2009] [Revised: 07/01/2009] [Accepted: 07/06/2009] [Indexed: 11/24/2022]
Abstract
The modification of serine and threonine residues of nuclear and cytoplasmic proteins by O-linked beta-N-acetylglucosamine (O-GlcNAc) has emerged as a highly dynamic post-translational modification that plays a critical role in regulating numerous biological processes. Much of our understanding of the mechanisms underlying the role of O-GlcNAc on cellular function has been in the context of its adverse effects in mediating a range of chronic disease processes, including diabetes, cancer and neurodegenerative diseases. However, at the cellular level it has been shown that O-GlcNAc levels are increased in response to stress; augmentation of this response improved cell survival while attenuation decreased cell viability. Thus, it has become apparent that strategies that augment O-GlcNAc levels are pro-survival, whereas those that reduce O-GlcNAc levels decrease cell survival. There is a long history demonstrating the effectiveness of acute glucose-insulin-potassium (GIK) treatment and to a lesser extent glutamine in protecting against a range of stresses, including myocardial ischemia. A common feature of these approaches for metabolic cardioprotection is that they both have the potential to stimulate O-GlcNAc synthesis. Consequently, here we examine the links between metabolic cardioprotection with the ischemic cardioprotection associated with acute increases in O-GlcNAc levels. Some of the protective mechanisms associated with activation of O-GlcNAcylation appear to be transcriptionally mediated; however, there is also strong evidence to suggest that transcriptionally independent mechanisms also play a critical role. In this context we discuss the potential link between O-GlcNAcylation and cardiomyocyte calcium homeostasis including the role of non-voltage gated, capacitative calcium entry as a potential mechanism contributing to this protection.
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Affiliation(s)
- John C Chatham
- Department of Medicine, Division of Cardiovascular Disease, Center for Free Radical Biology, Center for Aging and Clinical Nutrition Research Center, University of Alabama at Birmingham, Birmingham, AL, USA.
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164
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Glasnov TN, Groschner K, Kappe CO. High-speed microwave-assisted synthesis of the trifluoromethylpyrazol-derived canonical transient receptor potential (TRPC) channel inhibitor Pyr3. ChemMedChem 2010; 4:1816-8. [PMID: 19728347 DOI: 10.1002/cmdc.200900304] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Toma N Glasnov
- Institute of Chemistry, Karl-Franzens-University Graz, Austria
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165
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Chatham JC, Marchase RB. Protein O-GlcNAcylation: A critical regulator of the cellular response to stress. CURRENT SIGNAL TRANSDUCTION THERAPY 2010; 5:49-59. [PMID: 22308107 PMCID: PMC3270492 DOI: 10.2174/157436210790226492] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The post-translational modification of serine and threonine residues of nuclear and cytoplasmic proteins by the O-linked attachment of the monosaccharide ß-N-acetyl-glucosamine (O-GlcNAc) is a highly dynamic and ubiquitous protein modification that plays a critical role in regulating numerous biological processes. Much of our understanding of the mechanisms underlying the role of O-GlcNAc on cellular function has been in the context of chronic disease processes. However, there is increasing evidence that O-GlcNAc levels are increased in response to stress and that acute augmentation of this response is cytoprotective, at least in the short term. Conversely, a reduction in O-GlcNAc levels appears to be associated with decreased cell survival in response to an acute stress. Here we summarize our current understanding of protein O-GlcNAcylation on the cellular response to stress and in mediating cellular protective mechanisms focusing primarily on the cardiovascular system as an example. We consider the potential link between O-GlcNAcylation and cardiomyocyte calcium homeostasis and explore the parallels between O-GlcNAc signaling and redox signaling. We also discuss the apparent paradox between the reported adverse effects of increased O-GlcNAcylation with its recently reported role in mediating cell survival mechanisms.
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Affiliation(s)
- John C. Chatham
- Department of Medicine, Division of Cardiovascular Disease, Center for Free Radical Biology, Center for Aging and Clinical Nutrition Research Center, University of Alabama at Birmingham, Birmingham, AL
- Department of Cell Biology, University of Alabama at Birmingham, Birmingham, AL
| | - Richard B. Marchase
- Department of Cell Biology, University of Alabama at Birmingham, Birmingham, AL
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166
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Essential role of TRPC1 channels in cardiomyoblasts hypertrophy mediated by 5-HT2A serotonin receptors. Biochem Biophys Res Commun 2010; 391:979-83. [DOI: 10.1016/j.bbrc.2009.12.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Accepted: 12/02/2009] [Indexed: 11/21/2022]
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167
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Abstract
Atrial and brain natriuretic peptides (ANP and BNP, respectively) are cardiac hormones. During cardiac development, their expression is a maker of cardiomyocyte differentiation and is under tight spatiotemporal regulation. After birth, however, their ventricular expression is only up-regulated in response to various cardiovascular diseases. As a result, analysis of ANP and BNP gene expression has led to discoveries of transcriptional regulators and signaling pathways involved in both cardiac differentiation and cardiac disease. Studies using genetically engineered mice have shed light on the molecular mechanisms regulating ANP and BNP gene expression, as well as the physiological and pathophysiological relevance of the cardiac natriuretic peptide system. In this review we will summarize what is currently known about their regulation and the significance of ANP and BNP as hormones derived from the heart.
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Affiliation(s)
- Koichiro Kuwahara
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Sakyo-ku, Kyoto, Japan.
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168
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Mechanosensitive channels in striated muscle and the cardiovascular system: not quite a stretch anymore. J Cardiovasc Pharmacol 2009; 54:116-22. [PMID: 19597371 DOI: 10.1097/fjc.0b013e3181aa233f] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Stretch-activated or mechanosensitive channels transduce mechanical forces into ion fluxes across the cell membrane. These channels have been implicated in several aspects of cardiovascular physiology including regulation of blood pressure, vasoreactivity, and cardiac arrhythmias, as well as the adverse remodeling associated with cardiac hypertrophy and heart failure. This review discusses mechanosensitive channels in skeletal muscle and the cardiovascular system and their role in disease pathogenesis. We describe the regulation of gating of mechanosensitive channels including direct mechanisms and indirect activation by signaling pathways, as well as the influence on activation of these channels by the underlying cytoskeleton and scaffolding proteins. We then focus on the role of transient receptor potential channels, several of which have been implicated as mechanosensitive channels, in the pathogenesis of adverse cardiac remodeling and as potential therapeutic targets in the treatment of heart failure.
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169
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Koitabashi N, Aiba T, Hesketh GG, Rowell J, Zhang M, Takimoto E, Tomaselli GF, Kass DA. Cyclic GMP/PKG-dependent inhibition of TRPC6 channel activity and expression negatively regulates cardiomyocyte NFAT activation Novel mechanism of cardiac stress modulation by PDE5 inhibition. J Mol Cell Cardiol 2009; 48:713-24. [PMID: 19961855 DOI: 10.1016/j.yjmcc.2009.11.015] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2009] [Revised: 10/28/2009] [Accepted: 11/19/2009] [Indexed: 12/15/2022]
Abstract
Increased cyclic GMP from enhanced synthesis or suppressed catabolism (e.g. PDE5 inhibition by sildenafil, SIL) activates protein kinase G (PKG) and blunts cardiac pathological hypertrophy. Suppressed calcineurin (Cn)-NFAT (nuclear factor of activated T-cells) signaling appears to be involved, though it remains unclear how this is achieved. One potential mechanism involves activation of Cn/NFAT by calcium entering via transient receptor potential canonical (TRPC) channels (notably TRPC6). Here, we tested the hypothesis that PKG blocks Cn/NFAT activation by modifying and thus inhibiting TRPC6 current to break the positive feedback loop involving NFAT and NFAT-dependent TRPC6 upregulation. TRPC6 expression rose with pressure-overload in vivo, and angiotensin (ATII) or endothelin (ET1) stimulation in neonatal and adult cardiomyocytes in vitro. 8Br-cGMP and SIL reduced ET1-stimulated TRPC6 expression and NFAT dephosphorylation (activity). TRPC6 upregulation was absent if its promoter was mutated with non-functional NFAT binding sites, whereas constitutively active NFAT triggered TRPC6 expression that was not inhibited by SIL. PKG phosphorylated TRPC6, and both T70 and S322 were targeted. Both sites were functionally relevant, as 8Br-cGMP strongly suppressed current in wild-type TRPC6 channels, but not in those with phospho-silencing mutations (T70A, S322A or S322Q). NFAT activation and increased protein synthesis stimulated by ATII or ET1 was blocked by 8Br-cGMP or SIL. However, transfection with T70A or S322Q TRPC6 mutants blocked this inhibitory effect, whereas phospho-mimetic mutants (T70E, S322E, and both combined) suppressed NFAT activation. Thus PDE5-inhibition blocks TRPC6 channel activation and associated Cn/NFAT activation signaling by PKG-dependent channel phosphorylation.
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Affiliation(s)
- Norimichi Koitabashi
- Division of Cardiology, Ross 858, Department of Medicine, Johns Hopkins University Medical Institutions, 720 Rutland Avenue, Baltimore, MD 21205, USA
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170
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Nakayama H, Bodi I, Correll RN, Chen X, Lorenz J, Houser SR, Robbins J, Schwartz A, Molkentin JD. alpha1G-dependent T-type Ca2+ current antagonizes cardiac hypertrophy through a NOS3-dependent mechanism in mice. J Clin Invest 2009; 119:3787-96. [PMID: 19920353 DOI: 10.1172/jci39724] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2009] [Accepted: 09/23/2009] [Indexed: 12/21/2022] Open
Abstract
In noncontractile cells, increases in intracellular Ca2+ concentration serve as a second messenger to signal proliferation, differentiation, metabolism, motility, and cell death. Many of these Ca2+-dependent regulatory processes operate in cardiomyocytes, although it remains unclear how Ca2+ serves as a second messenger given the high Ca2+ concentrations that control contraction. T-type Ca2+ channels are reexpressed in adult ventricular myocytes during pathologic hypertrophy, although their physiologic function remains unknown. Here we generated cardiac-specific transgenic mice with inducible expression of alpha1G, which generates Cav3.1 current, to investigate whether this type of Ca2+ influx mechanism regulates the cardiac hypertrophic response. Unexpectedly, alpha1G transgenic mice showed no cardiac pathology despite large increases in Ca2+ influx, and they were even partially resistant to pressure overload-, isoproterenol-, and exercise-induced cardiac hypertrophy. Conversely, alpha1G-/- mice displayed enhanced hypertrophic responses following pressure overload or isoproterenol infusion. Enhanced hypertrophy and disease in alpha1G-/- mice was rescued with the alpha1G transgene, demonstrating a myocyte-autonomous requirement of alpha1G for protection. Mechanistically, alpha1G interacted with NOS3, which augmented cGMP-dependent protein kinase type I activity in alpha1G transgenic hearts after pressure overload. Further, the anti-hypertrophic effect of alpha1G overexpression was abrogated by a NOS3 inhibitor and by crossing the mice onto the Nos3-/- background. Thus, cardiac alpha1G reexpression and its associated pool of T-type Ca2+ antagonize cardiac hypertrophy through a NOS3-dependent signaling mechanism.
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Affiliation(s)
- Hiroyuki Nakayama
- Department of Pediatrics, University of Cincinnati, Division of Molecular Cardiovascular Biology, Howard Hughes Medical Institute, Children's Hospital Medical Center, Cincinnati, Ohio, USA
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171
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Miyagi K, Kiyonaka S, Yamada K, Miki T, Mori E, Kato K, Numata T, Sawaguchi Y, Numaga T, Kimura T, Kanai Y, Kawano M, Wakamori M, Nomura H, Koni I, Yamagishi M, Mori Y. A pathogenic C terminus-truncated polycystin-2 mutant enhances receptor-activated Ca2+ entry via association with TRPC3 and TRPC7. J Biol Chem 2009; 284:34400-12. [PMID: 19812035 DOI: 10.1074/jbc.m109.015149] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mutations in PKD2 gene result in autosomal dominant polycystic kidney disease (ADPKD). PKD2 encodes polycystin-2 (TRPP2), which is a homologue of transient receptor potential (TRP) cation channel proteins. Here we identify a novel PKD2 mutation that generates a C-terminal tail-truncated TRPP2 mutant 697fsX with a frameshift resulting in an aberrant 17-amino acid addition after glutamic acid residue 697 from a family showing mild ADPKD symptoms. When recombinantly expressed in HEK293 cells, wild-type (WT) TRPP2 localized at the endoplasmic reticulum (ER) membrane significantly enhanced Ca(2+) release from the ER upon muscarinic acetylcholine receptor (mAChR) stimulation. In contrast, 697fsX, which showed a predominant plasma membrane localization characteristic of TRPP2 mutants with C terminus deletion, prominently increased mAChR-activated Ca(2+) influx in cells expressing TRPC3 or TRPC7. Coimmunoprecipitation, pulldown assay, and cross-linking experiments revealed a physical association between 697fsX and TRPC3 or TRPC7. 697fsX but not WT TRPP2 elicited a depolarizing shift of reversal potentials and an enhancement of single-channel conductance indicative of altered ion-permeating pore properties of mAChR-activated currents. Importantly, in kidney epithelial LLC-PK1 cells the recombinant 679fsX construct was codistributed with native TRPC3 proteins at the apical membrane area, but the WT construct was distributed in the basolateral membrane and adjacent intracellular areas. Our results suggest that heteromeric cation channels comprised of the TRPP2 mutant and the TRPC3 or TRPC7 protein induce enhanced receptor-activated Ca(2+) influx that may lead to dysregulated cell growth in ADPKD.
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Affiliation(s)
- Kyoko Miyagi
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Japan
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172
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Seth M, Zhang ZS, Mao L, Graham V, Burch J, Stiber J, Tsiokas L, Winn M, Abramowitz J, Rockman HA, Birnbaumer L, Rosenberg P. TRPC1 channels are critical for hypertrophic signaling in the heart. Circ Res 2009; 105:1023-30. [PMID: 19797170 DOI: 10.1161/circresaha.109.206581] [Citation(s) in RCA: 168] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
RATIONALE Cardiac muscle adapts to increase workload by altering cardiomyocyte size and function resulting in cardiac hypertrophy. G protein-coupled receptor signaling is known to govern the hypertrophic response through the regulation of ion channel activity and downstream signaling in failing cardiomyocytes. OBJECTIVE Transient receptor potential canonical (TRPC) channels are G protein-coupled receptor operated channels previously implicated in cardiac hypertrophy. Our objective of this study is to better understand how TRPC channels influence cardiomyocyte calcium signaling. METHODS AND RESULTS Here, we used whole cell patch clamp of adult cardiomyocytes to show upregulation of a nonselective cation current reminiscent of TRPC channels subjected to pressure overload. This TRPC current corresponds to the increased TRPC channel expression noted in hearts of mice subjected to pressure overload. Importantly, we show that mice lacking TRPC1 channels are missing this putative TRPC current. Moreover, Trpc1(-)(/)(-) mice fail to manifest evidence of maladaptive cardiac hypertrophy and maintain preserved cardiac function when subjected to hemodynamic stress and neurohormonal excess. In addition, we provide a mechanistic basis for the protection conferred to Trpc1(-)(/)(-) mice as mechanosensitive signaling through calcineurin/NFAT, mTOR and Akt is altered in Trpc1(-)(/)(-) mice. CONCLUSIONS From these studies, we suggest that TRPC1 channels are critical for the adaptation to biomechanical stress and TRPC dysregulation leads to maladaptive cardiac hypertrophy and failure.
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Affiliation(s)
- Malini Seth
- Department of Medicine, Duke University School of Medicine, Durham, NC, USA
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173
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Differential expression of TRPC channels in the left ventricle of spontaneously hypertensive rats. Mol Biol Rep 2009; 37:2645-51. [PMID: 19757180 DOI: 10.1007/s11033-009-9792-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2008] [Accepted: 09/02/2009] [Indexed: 10/20/2022]
Abstract
This study was designed to identify the differential expression of the canonical transient receptor potential (TRPC) channels in the left ventricle of spontaneously hypertensive rats (SHR). Echocardiography studies were performed to compare the left ventricular function in SHR vs. Wistar-Kyoto rats (WKY), and the mRNA level of the TRPC channels was determined by quantitative real-time RT-PCR (qRT-PCR). Western blots were performed to examine whether the mRNA expression corresponded with the protein expression. Compared with the WKY, the mRNA expression of TRPC4 and TRPC5 was significantly increased in the 10-week-old SHR (P = 0.032 for TRPC4 and P = 0.043 for TRPC5), so did the TRPC4/5 protein content. The midwall fractional shortening (mFS) of SHR was lower than WKY (P = 0.016). Furthermore, increased expression of TRPC4/5 was correlated with both increased blood pressure and decreased mFS. These findings suggest that TRPC4 and 5 seem to be the main subtypes expressed in the heart of the SHR at the beginning period of hypertension. Theses channels may participate in the development of left ventricular systolic dysfunction.
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174
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Sensing pressure in the cardiovascular system: Gq-coupled mechanoreceptors and TRP channels. J Mol Cell Cardiol 2009; 48:83-9. [PMID: 19345226 DOI: 10.1016/j.yjmcc.2009.03.020] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2009] [Revised: 03/06/2009] [Accepted: 03/13/2009] [Indexed: 12/18/2022]
Abstract
Despite the central physiological importance of cardiovascular mechanotransduction, the molecular identities of the sensors and the signaling pathways have long remained elusive. Indeed, how pressure is transduced into cellular excitation has only recently started to emerge. In both arterial and cardiac myocytes, the diacylglycerol-sensitive canonical transient receptor potential (TRPC) subunits are proposed to underlie the stretch-activated depolarizing cation channels. An indirect mechanism of activation through a ligand-independent conformational switch of Gq-coupled receptors by mechanical stress is invoked. Such a mechanism involving the angiotensin type 1 receptor and TRPC6 is proposed to trigger the arterial myogenic response to intraluminal pressure. TRPC6 is also involved in load-induced cardiac hypertrophy. In this review, we will focus on the molecular basis of pressure sensing in the cardiovascular system and associated disease states.
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175
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Miyamoto S, Murphy AN, Brown JH. Akt mediated mitochondrial protection in the heart: metabolic and survival pathways to the rescue. J Bioenerg Biomembr 2009; 41:169-80. [PMID: 19377835 PMCID: PMC2732429 DOI: 10.1007/s10863-009-9205-y] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cardiomyocyte death is now recognized as a critical factor in the development of heart disease. Mitochondria are not only responsible for energy production to ensure that cardiac output meets the body's energy demands, but they serve as critical integrators of cell survival signals. Numerous stressors are known to induce cell death by necrosis and/or apoptosis mediated through mitochondrial dysregulation. Anti- and pro-apoptotic Bcl-2 family proteins regulate apoptosis by controlling mitochondrial outer membrane permeability, whereas opening of the mitochondrial permeability transition pore (PT-pore) induces large amplitude permeability of the inner membrane and consequent rupture of the outer membrane. Akt is one of the best described survival kinases activated by receptor ligands and its activation preserves mitochondrial integrity and protects cardiomyocytes against necrotic and apoptotic death. The mechanisms responsible for Akt-mediated mitochondrial protection have not been fully elucidated. There is, however, accumulating evidence that multiple Akt target molecules, recruited through both transcriptional and post-transcriptional mechanisms, directly impinge upon and protect mitochondria. In this review we discuss mechanisms by which Akt activation can effect changes at the mitochondria that protect cardiomyocytes and attenuate pathophysiological responses of the heart.
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Affiliation(s)
- Shigeki Miyamoto
- Department of Pharmacology, University of California, 9500 Gilman Dr., La Jolla, San Diego, CA 92093-0636, USA.
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176
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Kiyonaka S, Kato K, Nishida M, Mio K, Numaga T, Sawaguchi Y, Yoshida T, Wakamori M, Mori E, Numata T, Ishii M, Takemoto H, Ojida A, Watanabe K, Uemura A, Kurose H, Morii T, Kobayashi T, Sato Y, Sato C, Hamachi I, Mori Y. Selective and direct inhibition of TRPC3 channels underlies biological activities of a pyrazole compound. Proc Natl Acad Sci U S A 2009; 106:5400-5. [PMID: 19289841 PMCID: PMC2664023 DOI: 10.1073/pnas.0808793106] [Citation(s) in RCA: 283] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Indexed: 12/31/2022] Open
Abstract
Canonical transient receptor potential (TRPC) channels control influxes of Ca(2+) and other cations that induce diverse cellular processes upon stimulation of plasma membrane receptors coupled to phospholipase C (PLC). Invention of subtype-specific inhibitors for TRPCs is crucial for distinction of respective TRPC channels that play particular physiological roles in native systems. Here, we identify a pyrazole compound (Pyr3), which selectively inhibits TRPC3 channels. Structure-function relationship studies of pyrazole compounds showed that the trichloroacrylic amide group is important for the TRPC3 selectivity of Pyr3. Electrophysiological and photoaffinity labeling experiments reveal a direct action of Pyr3 on the TRPC3 protein. In DT40 B lymphocytes, Pyr3 potently eliminated the Ca(2+) influx-dependent PLC translocation to the plasma membrane and late oscillatory phase of B cell receptor-induced Ca(2+) response. Moreover, Pyr3 attenuated activation of nuclear factor of activated T cells, a Ca(2+)-dependent transcription factor, and hypertrophic growth in rat neonatal cardiomyocytes, and in vivo pressure overload-induced cardiac hypertrophy in mice. These findings on important roles of native TRPC3 channels are strikingly consistent with previous genetic studies. Thus, the TRPC3-selective inhibitor Pyr3 is a powerful tool to study in vivo function of TRPC3, suggesting a pharmaceutical potential of Pyr3 in treatments of TRPC3-related diseases such as cardiac hypertrophy.
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Affiliation(s)
| | | | - Motohiro Nishida
- Department of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Kyushu University, Higashiku, Fukuoka 812-8582, Japan
| | - Kazuhiro Mio
- Neuroscience Research Institute, National Institute of Advanced Industrial Science and Technology, Umezono 1-1-4, Tsukuba Ibaraki 305-8568, Japan
| | | | | | | | | | | | | | - Masakazu Ishii
- Department of Pathophysiology, School of Pharmaceutical Sciences, Showa University, Tokyo 142-8555, Japan
| | - Hiroki Takemoto
- Laboratory of Bioorganic Chemistry, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan
| | - Akio Ojida
- Laboratory of Bioorganic Chemistry, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan
| | - Kenta Watanabe
- Department of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Kyushu University, Higashiku, Fukuoka 812-8582, Japan
| | - Aya Uemura
- Department of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Kyushu University, Higashiku, Fukuoka 812-8582, Japan
| | - Hitoshi Kurose
- Department of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Kyushu University, Higashiku, Fukuoka 812-8582, Japan
| | - Takashi Morii
- Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Tsutomu Kobayashi
- Pharmacology Laboratory, Mitsubishi Tanabe Pharma Corporation 2-2-50, Kawagishi, Toda 335-8505, Japan; and
| | - Yoji Sato
- National Institute of Health Sciences, Setagaya, Tokyo 158-8501, Japan
| | - Chikara Sato
- Neuroscience Research Institute, National Institute of Advanced Industrial Science and Technology, Umezono 1-1-4, Tsukuba Ibaraki 305-8568, Japan
| | - Itaru Hamachi
- Laboratory of Bioorganic Chemistry, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan
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177
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Wu X, Chang B, Blair NS, Sargent M, York AJ, Robbins J, Shull GE, Molkentin JD. Plasma membrane Ca2+-ATPase isoform 4 antagonizes cardiac hypertrophy in association with calcineurin inhibition in rodents. J Clin Invest 2009; 119:976-85. [PMID: 19287093 DOI: 10.1172/jci36693] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2008] [Accepted: 02/04/2009] [Indexed: 01/19/2023] Open
Abstract
How Ca2+-dependent signaling effectors are regulated in cardiomyocytes, given the extreme cytoplasmic Ca2+ concentration changes that underlie contraction, remains unknown. Cardiomyocyte plasma membrane Ca2+-ATPase (PMCA) extrudes Ca2+ but has little effect on excitation-contraction coupling, suggesting its potential role in controlling Ca2+-dependent signaling effectors such as calcineurin. We generated cardiac-specific inducible PMCA4b transgenic mice that displayed normal global Ca2+ transient and cellular contraction levels and reduced cardiac hypertrophy following transverse aortic constriction (TAC) or phenylephrine/Ang II infusion, but showed no reduction in exercise-induced hypertrophy. Transgenic mice were protected from decompensation and fibrosis following long-term TAC. The PMCA4b transgene reduced the hypertrophic augmentation associated with transient receptor potential canonical 3 channel overexpression, but not that associated with activated calcineurin. Furthermore, Pmca4 gene-targeted mice showed increased cardiac hypertrophy and heart failure events after TAC. Physical associations between PMCA4b and calcineurin were enhanced by TAC and by agonist stimulation of cultured neonatal cardiomyocytes. PMCA4b reduced calcineurin nuclear factor of activated T cell-luciferase activity after TAC and in cultured neonatal cardiomyocytes after agonist stimulation. PMCA4b overexpression inhibited cultured cardiomyocyte hypertrophy following agonist stimulation, but much less so in a Ca2+ pumping-deficient PMCA4b mutant. Thus, Pmca4b likely reduces the local Ca2+ signals involved in reactive cardiomyocyte hypertrophy via calcineurin regulation.
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Affiliation(s)
- Xu Wu
- Department of Pediatrics, Division of Molecular Cardiovascular Biology, University of Cincinnati, Cincinnati, Ohio 45229, USA
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178
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Chiang CS, Huang CH, Chieng H, Chang YT, Chang D, Chen JJ, Chen YC, Chen YH, Shin HS, Campbell KP, Chen CC. The Ca
V
3.2 T-Type Ca
2+
Channel Is Required for Pressure Overload–Induced Cardiac Hypertrophy in Mice. Circ Res 2009; 104:522-30. [DOI: 10.1161/circresaha.108.184051] [Citation(s) in RCA: 131] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Voltage-gated T-type Ca
2+
channels (T-channels) are normally expressed during embryonic development in ventricular myocytes but are undetectable in adult ventricular myocytes. Interestingly, T-channels are reexpressed in hypertrophied or failing hearts. It is unclear whether T-channels play a role in the pathogenesis of cardiomyopathy and what the mechanism might be. Here we show that the α
1H
voltage-gated T-type Ca
2+
channel (Ca
v
3.2) is involved in the pathogenesis of cardiac hypertrophy via the activation of calcineurin/nuclear factor of activated T cells (NFAT) pathway. Specifically, pressure overload–induced hypertrophy was severely suppressed in mice deficient for Ca
v
3.2 (Ca
v
3.2
−/−
) but not in mice deficient for Ca
v
3.1 (Ca
v
3.1
−/−
). Angiotensin II–induced cardiac hypertrophy was also suppressed in Ca
v
3.2
−/−
mice. Consistent with these findings, cultured neonatal myocytes isolated from Ca
v
3.2
−/−
mice fail to respond hypertrophic stimulation by treatment with angiotensin II. Together, these results demonstrate the importance of Ca
v
3.2 in the development of cardiac hypertrophy both in vitro and in vivo. To test whether Ca
v
3.2 mediates the hypertrophic response through the calcineurin/NFAT pathway, we generated Ca
v
3.2
−/−
, NFAT-luciferase reporter mice and showed that NFAT-luciferase reporter activity failed to increase after pressure overload in the Ca
v
3.2
−/−
/NFAT-Luc mice. Our results provide strong genetic evidence that Ca
v
3.2 indeed plays a pivotal role in the induction of calcineurin/NFAT hypertrophic signaling and is crucial for the activation of pathological cardiac hypertrophy.
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Affiliation(s)
- Chien-Sung Chiang
- From the Institute of Biomedical Sciences (C.-S.C., C.-H.H., H.C., Y.-T.C., D.C., J.-J.C., Y.-C.C.,Y.-H.C., C.-C.C.), Academia Sinica, Taipei, Taiwan; Graduate Institute of Life Sciences (C.-H.H., C.-C.C.), National Defense Medical Center, Taipei, Taiwan; Center for Neural Science (H.-S.S.), Korea Institute of Science and Technology, Seoul, Korea; and Department of Physiology and Biophysics and Department of Neurology (K.P.C.), Howard Hughes Medical Institute, University of Iowa, Iowa City
| | - Ching-Hui Huang
- From the Institute of Biomedical Sciences (C.-S.C., C.-H.H., H.C., Y.-T.C., D.C., J.-J.C., Y.-C.C.,Y.-H.C., C.-C.C.), Academia Sinica, Taipei, Taiwan; Graduate Institute of Life Sciences (C.-H.H., C.-C.C.), National Defense Medical Center, Taipei, Taiwan; Center for Neural Science (H.-S.S.), Korea Institute of Science and Technology, Seoul, Korea; and Department of Physiology and Biophysics and Department of Neurology (K.P.C.), Howard Hughes Medical Institute, University of Iowa, Iowa City
| | - Hockling Chieng
- From the Institute of Biomedical Sciences (C.-S.C., C.-H.H., H.C., Y.-T.C., D.C., J.-J.C., Y.-C.C.,Y.-H.C., C.-C.C.), Academia Sinica, Taipei, Taiwan; Graduate Institute of Life Sciences (C.-H.H., C.-C.C.), National Defense Medical Center, Taipei, Taiwan; Center for Neural Science (H.-S.S.), Korea Institute of Science and Technology, Seoul, Korea; and Department of Physiology and Biophysics and Department of Neurology (K.P.C.), Howard Hughes Medical Institute, University of Iowa, Iowa City
| | - Ya-Ting Chang
- From the Institute of Biomedical Sciences (C.-S.C., C.-H.H., H.C., Y.-T.C., D.C., J.-J.C., Y.-C.C.,Y.-H.C., C.-C.C.), Academia Sinica, Taipei, Taiwan; Graduate Institute of Life Sciences (C.-H.H., C.-C.C.), National Defense Medical Center, Taipei, Taiwan; Center for Neural Science (H.-S.S.), Korea Institute of Science and Technology, Seoul, Korea; and Department of Physiology and Biophysics and Department of Neurology (K.P.C.), Howard Hughes Medical Institute, University of Iowa, Iowa City
| | - Dory Chang
- From the Institute of Biomedical Sciences (C.-S.C., C.-H.H., H.C., Y.-T.C., D.C., J.-J.C., Y.-C.C.,Y.-H.C., C.-C.C.), Academia Sinica, Taipei, Taiwan; Graduate Institute of Life Sciences (C.-H.H., C.-C.C.), National Defense Medical Center, Taipei, Taiwan; Center for Neural Science (H.-S.S.), Korea Institute of Science and Technology, Seoul, Korea; and Department of Physiology and Biophysics and Department of Neurology (K.P.C.), Howard Hughes Medical Institute, University of Iowa, Iowa City
| | - Ji-Jr Chen
- From the Institute of Biomedical Sciences (C.-S.C., C.-H.H., H.C., Y.-T.C., D.C., J.-J.C., Y.-C.C.,Y.-H.C., C.-C.C.), Academia Sinica, Taipei, Taiwan; Graduate Institute of Life Sciences (C.-H.H., C.-C.C.), National Defense Medical Center, Taipei, Taiwan; Center for Neural Science (H.-S.S.), Korea Institute of Science and Technology, Seoul, Korea; and Department of Physiology and Biophysics and Department of Neurology (K.P.C.), Howard Hughes Medical Institute, University of Iowa, Iowa City
| | - Yong-Cyuan Chen
- From the Institute of Biomedical Sciences (C.-S.C., C.-H.H., H.C., Y.-T.C., D.C., J.-J.C., Y.-C.C.,Y.-H.C., C.-C.C.), Academia Sinica, Taipei, Taiwan; Graduate Institute of Life Sciences (C.-H.H., C.-C.C.), National Defense Medical Center, Taipei, Taiwan; Center for Neural Science (H.-S.S.), Korea Institute of Science and Technology, Seoul, Korea; and Department of Physiology and Biophysics and Department of Neurology (K.P.C.), Howard Hughes Medical Institute, University of Iowa, Iowa City
| | - Yen-Hui Chen
- From the Institute of Biomedical Sciences (C.-S.C., C.-H.H., H.C., Y.-T.C., D.C., J.-J.C., Y.-C.C.,Y.-H.C., C.-C.C.), Academia Sinica, Taipei, Taiwan; Graduate Institute of Life Sciences (C.-H.H., C.-C.C.), National Defense Medical Center, Taipei, Taiwan; Center for Neural Science (H.-S.S.), Korea Institute of Science and Technology, Seoul, Korea; and Department of Physiology and Biophysics and Department of Neurology (K.P.C.), Howard Hughes Medical Institute, University of Iowa, Iowa City
| | - Hee-Sup Shin
- From the Institute of Biomedical Sciences (C.-S.C., C.-H.H., H.C., Y.-T.C., D.C., J.-J.C., Y.-C.C.,Y.-H.C., C.-C.C.), Academia Sinica, Taipei, Taiwan; Graduate Institute of Life Sciences (C.-H.H., C.-C.C.), National Defense Medical Center, Taipei, Taiwan; Center for Neural Science (H.-S.S.), Korea Institute of Science and Technology, Seoul, Korea; and Department of Physiology and Biophysics and Department of Neurology (K.P.C.), Howard Hughes Medical Institute, University of Iowa, Iowa City
| | - Kevin P. Campbell
- From the Institute of Biomedical Sciences (C.-S.C., C.-H.H., H.C., Y.-T.C., D.C., J.-J.C., Y.-C.C.,Y.-H.C., C.-C.C.), Academia Sinica, Taipei, Taiwan; Graduate Institute of Life Sciences (C.-H.H., C.-C.C.), National Defense Medical Center, Taipei, Taiwan; Center for Neural Science (H.-S.S.), Korea Institute of Science and Technology, Seoul, Korea; and Department of Physiology and Biophysics and Department of Neurology (K.P.C.), Howard Hughes Medical Institute, University of Iowa, Iowa City
| | - Chien-Chang Chen
- From the Institute of Biomedical Sciences (C.-S.C., C.-H.H., H.C., Y.-T.C., D.C., J.-J.C., Y.-C.C.,Y.-H.C., C.-C.C.), Academia Sinica, Taipei, Taiwan; Graduate Institute of Life Sciences (C.-H.H., C.-C.C.), National Defense Medical Center, Taipei, Taiwan; Center for Neural Science (H.-S.S.), Korea Institute of Science and Technology, Seoul, Korea; and Department of Physiology and Biophysics and Department of Neurology (K.P.C.), Howard Hughes Medical Institute, University of Iowa, Iowa City
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179
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Abramowitz J, Birnbaumer L. Physiology and pathophysiology of canonical transient receptor potential channels. FASEB J 2009; 23:297-328. [PMID: 18940894 PMCID: PMC2630793 DOI: 10.1096/fj.08-119495] [Citation(s) in RCA: 252] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2008] [Accepted: 09/25/2008] [Indexed: 11/11/2022]
Abstract
The existence of a mammalian family of TRPC ion channels, direct homologues of TRP, the visual transduction channel of flies, was discovered during 1995-1996 as a consequence of research into the mechanism by which the stimulation of the receptor-Gq-phospholipase Cbeta signaling pathway leads to sustained increases in intracellular calcium. Mammalian TRPs, TRPCs, turned out to be nonselective, calcium-permeable cation channels, which cause both a collapse of the cell's membrane potential and entry of calcium. The family comprises 7 members and is widely expressed. Many cells and tissues express between 3 and 4 of the 7 TRPCs. Despite their recent discovery, a wealth of information has accumulated, showing that TRPCs have widespread roles in almost all cells studied, including cells from excitable and nonexcitable tissues, such as the nervous and cardiovascular systems, the kidney and the liver, and cells from endothelia, epithelia, and the bone marrow compartment. Disruption of TRPC function is at the root of some familial diseases. More often, TRPCs are contributing risk factors in complex diseases. The present article reviews what has been uncovered about physiological roles of mammalian TRPC channels since the time of their discovery. This analysis reveals TRPCs as major and unsuspected gates of Ca(2+) entry that contribute, depending on context, to activation of transcription factors, apoptosis, vascular contractility, platelet activation, and cardiac hypertrophy, as well as to normal and abnormal cell proliferation. TRPCs emerge as targets for a thus far nonexistent field of pharmacological intervention that may ameliorate complex diseases.
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Affiliation(s)
- Joel Abramowitz
- Transmembrane Signaling Group, Laboratory of Neurobiology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA.
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180
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Endothelin-1-Stimulated InsP3-Induced Ca2+ Release Is a Nexus for Hypertrophic Signaling in Cardiac Myocytes. Mol Cell 2009; 33:472-82. [DOI: 10.1016/j.molcel.2009.02.005] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2007] [Revised: 10/24/2008] [Accepted: 02/10/2009] [Indexed: 11/20/2022]
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181
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Schlöndorff J, Del Camino D, Carrasquillo R, Lacey V, Pollak MR. TRPC6 mutations associated with focal segmental glomerulosclerosis cause constitutive activation of NFAT-dependent transcription. Am J Physiol Cell Physiol 2009; 296:C558-69. [PMID: 19129465 DOI: 10.1152/ajpcell.00077.2008] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Mutations in the canonical transient receptor potential channel TRPC6 lead to an autosomal dominant form of human kidney disease characterized histologically by focal and segmental glomerulosclerosis. Several of these mutations enhance the amplitude and duration of the channel current. However, the effect of these mutations on the downstream target of TRPC6, the nuclear factor of activated T cell (NFAT) transcription factors, has not been previously examined. Here we demonstrate that all three TRPC6 mutations previously shown to enhance channel activity lead to enhanced basal NFAT-mediated transcription in several cell lines, including cultured podocytes. These effects are dependent on channel activity and are dominant when mutants are coexpressed with wild-type TRPC6. While TRPC6 mutants do not demonstrate an increase in basal channel currents, a subset of cells expressing the R895C and E897K mutants have elevated basal calcium levels as measured by Fura-2 imaging. Activation of NFAT by TRPC6 mutants is blocked by inhibitors of calcineurin, calmodulin-dependent kinase II, and phosphatidylinositol 3-kinase. PP2 partially inhibits NFAT activation by mutant TRPC6 independently of Src, Yes, or Fyn. Differences in channel glycosylation and surface expression do not explain the ability of mutants to enhance NFAT activation. Taken together, these results identify the activation of the calcineurin-NFAT pathway as a potential mediator of focal segmental glomerulosclerosis.
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Affiliation(s)
- Johannes Schlöndorff
- Renal Division, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
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182
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RNA interference targeting STIM1 suppresses vascular smooth muscle cell proliferation and neointima formation in the rat. Mol Ther 2008; 17:455-62. [PMID: 19107116 DOI: 10.1038/mt.2008.291] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Our objective was to study the expression and function of stromal interaction molecule 1 (STIM1), an endoplasmic reticulum protein recently identified as the calcium sensor that regulated Ca(2+)-released activated channels in T cells. STIM1 was found to be upregulated in serum-induced proliferating human coronary artery smooth muscle cells (hCASMCs) as well as in the neointima of injured rat carotid arteries. Growth factors-induced proliferation was significantly lower in hCASMC transfected with STIM1 siRNA than in those transfected with scrambled siRNA (increase relative to 0.1% S: 116 +/- 12% and 184 +/- 16%, respectively, P < 0.01). To assess the role of STIM1 in preventing vascular smooth muscle cells (VSMCs) proliferation in vivo, we infected balloon-injured rat carotid arteries with an adenoviral vector expressing a short hairpin (sh) RNA against rat STIM1 mRNA (Ad-shSTIM1). Intima/media ratios reflecting the degree of restenosis were significantly lower in Ad-shSTIM1- infected arteries than in Ad-shLuciferase-infected arteries (0.34 +/- 0.02 vs. 0.92 +/- 0.11, P < 0.006). Finally, we demonstrated that silencing STIM1 prevents activation of the transcription factor NFAT (nuclear factor of activated T cell). In conclusion, STIM1 appears as a major regulator of in vitro and in vivo VSMC proliferation, representing a novel and original pharmacological target for prominent vascular proliferative diseases.
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183
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Qin N, Gong QH, Wei LW, Wu Q, Huang XN. Total ginsenosides inhibit the right ventricular hypertrophy induced by monocrotaline in rats. Biol Pharm Bull 2008; 31:1530-5. [PMID: 18670084 DOI: 10.1248/bpb.31.1530] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ginsenosides have been reported to release nitric oxide (NO) and decrease intracellular free Ca(2+) in cardiovascular system, which play important roles in antihypertrophic effect. This study investigated the potential inhibitory effect of total ginsenosides (TG) on right ventricular hypertrophy induced by monocrotaline (MCT, 60 mg/kg/d) and examined the possible antihypertrophic mechanism in male Sprague Dawley rats. MCT-intoxicated animals were treated with TG (20, 40, 60 mg/kg/d) for 18 d. TG treatment ameliorated MCT-induced elevations in right ventricular peak systolic pressure, right ventricular hypertrophy and the expression of atrial natriuretic peptide; N(G)-nitro-L-arginine-methyl ester (L-NAME), an NO synthase (NOS) inhibitor, had no influence on these inhibitory effects of TG 40 mg/kg/d, and TG at this dose had no any effect on the eNOS mRNA expression, suggesting the limited rule of NO in TG's effects. To further examine the mechanisms of the protection, the expression of calcineurin and its catalytic subunit CnA, as well as extracellular signal-regulated kinase-1 (ERK-1) and mitogen-activated protein kinase (MAPK) Phosphatase-1 (MKP-1) was examined. TG treatment significantly suppressed MCT-induced elevations of these signaling pathways in a dose-dependent manner. In summary, TG is effective in protecting against MCT-induced right ventricle hypertrophy, possibly through lowering pulmonary hypertension. Multiple molecular mechanisms appeared to be involved in this protection, such as the suppression of MCT-activated calcineurin and ERK signaling pathways.
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Affiliation(s)
- Na Qin
- Department of Pharmacology, Zunyi Medical College, Zunyi, China
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184
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Smedlund K, Vazquez G. Involvement of native TRPC3 proteins in ATP-dependent expression of VCAM-1 and monocyte adherence in coronary artery endothelial cells. Arterioscler Thromb Vasc Biol 2008; 28:2049-55. [PMID: 18787184 DOI: 10.1161/atvbaha.108.175356] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
UNLABELLED Background- Vascular cell adhesion molecule-1 (VCAM-1) is critical in monocyte recruitment to the endothelium, a key event in development of atherosclerotic lesions. Stimulation of human coronary artery endothelial cells (HCAECs) with ATP positively modulates VCAM-1 expression and function through a mechanism involving Ca(2+) signaling. We here examined the role of Ca(2+) influx and native TRPC3 channels in that mechanism. METHODS AND RESULTS Omission of extracellular Ca(2+) or pretreatment of cells with channel blockers markedly reduced ATP-induced VCAM-1 and monocyte adhesion. Using a siRNA strategy and real-time fluorescence, we found that native TRPC3 proteins contribute to constitutive and ATP-regulated Ca(2+) influx. ATP-dependent upregulation of VCAM-1 was accompanied by an increase in basal cation entry and TRPC3 expression. Notably, TRPC3 knock-down resulted in a dramatic reduction of ATP-induced VCAM-1 and monocyte adhesion. CONCLUSIONS These findings indicate that in HCAECs, native TRPC3 proteins form channels that contribute to constitutive and ATP-dependent Ca(2+) influx, and that TRPC3 expression and function are fundamental to support VCAM-1 expression and monocyte binding. This is the first evidence to date relating native TRPC3 proteins with regulated expression of cell adhesion molecules in coronary endothelium, and suggests a potential pathophysiological role of TRPC3 in coronary artery disease.
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Affiliation(s)
- Kathryn Smedlund
- Department of Physiology and Pharmacology, Center for Diabetes and Endocrine Research, University of Toledo College of Medicine, Health Science Campus, Ohio 43614, USA
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185
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Ho JWK, Stefani M, dos Remedios CG, Charleston MA. Differential variability analysis of gene expression and its application to human diseases. Bioinformatics 2008; 24:i390-8. [PMID: 18586739 PMCID: PMC2718620 DOI: 10.1093/bioinformatics/btn142] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
MOTIVATION Current microarray analyses focus on identifying sets of genes that are differentially expressed (DE) or differentially coexpressed (DC) in different biological states (e.g. diseased versus non-diseased). We observed that in many human diseases, some genes have a significant increase or decrease in expression variability (variance). As these observed changes in expression variability may be caused by alteration of the underlying expression dynamics, such differential variability (DV) patterns are also biologically interesting. RESULTS Here we propose a novel analysis for changes in gene expression variability between groups of samples, which we call differential variability analysis. We introduce the concept of differential variability (DV), and present a simple procedure for identifying DV genes from microarray data. Our procedure is evaluated with simulated and real microarray datasets. The effect of data preprocessing methods on identification of DV gene is investigated. The biological significance of DV analysis is demonstrated with four human disease datasets. The relationships among DV, DE and DC genes are investigated. The results suggest that changes in expression variability are associated with changes in coexpression pattern, which imply that DV is not merely stochastic noise, but informative signal. AVAILABILITY The R source code for differential variability analysis is available from the contact authors upon request.
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Affiliation(s)
- Joshua W K Ho
- School of Information Technologies, The University of Sydney, Sydney, NSW 2006, Australia.
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186
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Roles of TRP channels in the development of cardiac hypertrophy. Naunyn Schmiedebergs Arch Pharmacol 2008; 378:395-406. [DOI: 10.1007/s00210-008-0321-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2008] [Accepted: 06/02/2008] [Indexed: 10/21/2022]
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187
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Hidalgo C, Donoso P. Crosstalk between calcium and redox signaling: from molecular mechanisms to health implications. Antioxid Redox Signal 2008; 10:1275-312. [PMID: 18377233 DOI: 10.1089/ars.2007.1886] [Citation(s) in RCA: 143] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Studies done many years ago established unequivocally the key role of calcium as a universal second messenger. In contrast, the second messenger roles of reactive oxygen and nitrogen species have emerged only recently. Therefore, their contributions to physiological cell signaling pathways have not yet become universally accepted, and many biological researchers still regard them only as cellular noxious agents. Furthermore, it is becoming increasingly apparent that there are significant interactions between calcium and redox species, and that these interactions modify a variety of proteins that participate in signaling transduction pathways and in other fundamental cellular functions that determine cell life or death. This review article addresses first the central aspects of calcium and redox signaling pathways in animal cells, and continues with the molecular mechanisms that underlie crosstalk between calcium and redox signals under a number of physiological or pathological conditions. To conclude, the review focuses on conditions that, by promoting cellular oxidative stress, lead to the generation of abnormal calcium signals, and how this calcium imbalance may cause a variety of human diseases including, in particular, degenerative diseases of the central nervous system and cardiac pathologies.
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Affiliation(s)
- Cecilia Hidalgo
- Centro FONDAP de Estudios Moleculares de la Célula and Programa de Biología Molecular y Celular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
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188
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189
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Tokudome T, Kishimoto I, Horio T, Arai Y, Schwenke DO, Hino J, Okano I, Kawano Y, Kohno M, Miyazato M, Nakao K, Kangawa K. Regulator of G-protein signaling subtype 4 mediates antihypertrophic effect of locally secreted natriuretic peptides in the heart. Circulation 2008; 117:2329-39. [PMID: 18443239 DOI: 10.1161/circulationaha.107.732990] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Mice lacking guanylyl cyclase-A (GC-A), a natriuretic peptide receptor, have pressure-independent cardiac hypertrophy. However, the mechanism underlying GC-A-mediated inhibition of cardiac hypertrophy remains to be elucidated. In the present report, we examined the role of regulator of G-protein signaling subtype 4 (RGS4), a GTPase activating protein for G(q) and G(i), in the antihypertrophic effects of GC-A. METHODS AND RESULTS In cultured cardiac myocytes, treatment of atrial natriuretic peptide stimulated the binding of guanosine 3',5'-cyclic monophosphate-dependent protein kinase (PKG) I-alpha to RGS4, PKG-dependent phosphorylation of RGS4, and association of RGS4 and Galpha(q). In contrast, blockade of GC-A by an antagonist, HS-142-1, attenuated the phosphorylation of RGS4 and association of RGS4 and Galpha(q). Moreover, overexpressing a dominant negative form of RGS4 diminished the inhibitory effects of atrial natriuretic peptide on endothelin-1-stimulated inositol 1,4,5-triphosphate production, [(3)H]leucine incorporation, and atrial natriuretic peptide gene expression. Furthermore, expression and phosphorylation of RGS4 were significantly reduced in the hearts of GC-A knockout (GC-A-KO) mice compared with wild-type mice. For further investigation, we constructed cardiomyocyte-specific RGS4 transgenic mice and crossbred them with GC-A-KO mice. The cardiac RGS4 overexpression in GC-A-KO mice significantly reduced the ratio of heart to body weight (P<0.001), cardiomyocyte size (P<0.01), and ventricular calcineurin activity (P<0.05) to 80%, 76%, and 67% of nontransgenic GC-A-KO mice, respectively. It also significantly suppressed the augmented cardiac expression of hypertrophy-related genes in GC-A-KO mice. CONCLUSIONS These results provide evidence that GC-A activates cardiac RGS4, which attenuates Galpha(q) and its downstream hypertrophic signaling, and that RGS4 plays important roles in GC-A-mediated inhibition of cardiac hypertrophy.
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Affiliation(s)
- Takeshi Tokudome
- Department of Medicine, National Cardiovascular Center, 5-7-1, Fujishirodai, Suita, Osaka 565-8565, Japan
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190
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Kirchhof P, Fortmüller L, Waldeyer C, Breithardt G, Fabritz L. Drugs that interact with cardiac electro-mechanics: old and new targets for treatment. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2008; 97:497-512. [PMID: 18406454 DOI: 10.1016/j.pbiomolbio.2008.02.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The concept of mechano-electrical feedback was derived from the observation that a short stretch applied to the beating heart can invoke an electrical response in the form of an afterdepolarization or a premature ventricular beat. More recent work has identified stretch-activated channels whose specific inhibition might help to treat atrial fibrillation in the near future. But the interaction between electrical and mechanical function of the heart is a continuum from short-term (within milliseconds) to long-term (within weeks or months) effects. The long-term effects of pressure overload have been well-described on the molecular and cellular level, and substances that interact with these processes are used in clinical routine in the care of patients with cardiac hypertrophy and heart failure. These treatments help to prevent lethal arrhythmias (sudden death) and potentially atrial fibrillation. The intermediate interaction between mechanical and electrical function of the heart is less well-understood. Several recently identified regulatory mechanisms may provide novel antiarrhythmic targets associated with the "intermediate" response of the myocardium to stretch.
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Affiliation(s)
- Paulus Kirchhof
- Department of Cardiology and Angiology, Hospital of the University of Münster, Münster, Germany.
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191
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Role of sarco/endoplasmic reticulum calcium content and calcium ATPase activity in the control of cell growth and proliferation. Pflugers Arch 2008; 457:673-85. [PMID: 18188588 DOI: 10.1007/s00424-007-0428-7] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2007] [Accepted: 12/11/2007] [Indexed: 12/11/2022]
Abstract
Ca(2+), the main second messenger, is central to the regulation of cellular growth. There is increasing evidence that cellular growth and proliferation are supported by a continuous store-operated Ca(2+) influx. By controlling store refilling, the sarco/endoplasmic reticulum Ca(2+) ATPase (SERCA) also controls store-operated calcium entry and, thus, cell growth. In this review, we discuss data showing the involvement of SERCA in the regulation of proliferation and hypertrophy. First, we describe the Ca(2+)-related signaling pathways involved in cell growth. Then, we present evidence that SERCA controls proliferation of differentiated cells and hypertrophic growth of cardiomyocytes, and discuss the role of SERCA isoforms. Last, we consider the potential therapeutic applications of increasing SERCA activity for the treatment of cardiovascular diseases and of modulating SERCA and SR content for the treatment of cancer.
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192
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Shan D, Marchase RB, Chatham JC. Overexpression of TRPC3 increases apoptosis but not necrosis in response to ischemia-reperfusion in adult mouse cardiomyocytes. Am J Physiol Cell Physiol 2008; 294:C833-41. [PMID: 18184877 DOI: 10.1152/ajpcell.00313.2007] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
An increase in cytosolic Ca2+ via a capacitative calcium entry (CCE)-mediated pathway, attributed to members of the transient receptor potential (TRP) superfamily, TRPC1 and TRPC3, has been reported to play an important role in regulating cardiomyocyte hypertrophy. Increased cytosolic Ca2+ also plays a critical role in mediating cell death in response to ischemia-reperfusion (I/R). Therefore, we tested the hypothesis that overexpression of TRPC3 in cardiomyocytes will increase sensitivity to I/R injury. Adult cardiomyocytes isolated from wild-type (WT) mice and from mice overexpressing TRPC3 in the heart were subjected to 90 min of ischemia and 3 h of reperfusion. After I/R, viability was 51 +/- 1% in WT mice and 42 +/- 5% in transgenic mice (P < 0.05). Apoptosis assessed by annexin V was significantly increased in the TRPC3 group compared with WT (32 +/- 1% vs. 21 +/- 3%; P < 0.05); however, there was no significant difference in necrosis between groups. Treatment of TRPC3 cells with the CCE inhibitor SKF-96365 (0.5 microM) significantly improved cellular viability (54 +/- 4%) and decreased apoptosis (15 +/- 4%); in contrast, the L-type Ca2+ channel inhibitor verapamil (10 microM) had no effect. Calpain-mediated cleavage of alpha-fodrin was increased approximately threefold in the transgenic group following I/R compared with WT (P < 0.05); this was significantly attenuated by SKF-96365. The calpain inhibitor PD-150606 (25 microM) attenuated the increase in both alpha-fodrin cleavage and apoptosis in the TPRC3 group. Increased TRPC3 expression also increased sensitivity to Ca2+ overload stress, but it did not affect the response to TNF-alpha-induced apoptosis. These results suggest that CCE mediated via TRPC may play a role in cardiomyocyte apoptosis following I/R due, at least in part, to increased calpain activation.
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Affiliation(s)
- Dan Shan
- Division of Cardiovascular Disease, Dept. of Medicine, Univ. of Alabama at Birmingham, Birmingham, AL 35294-0005, USA
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193
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Nakayama H, Chen X, Baines CP, Klevitsky R, Zhang X, Zhang H, Jaleel N, Chua BH, Hewett TE, Robbins J, Houser SR, Molkentin JD. Ca2+- and mitochondrial-dependent cardiomyocyte necrosis as a primary mediator of heart failure. J Clin Invest 2007; 117:2431-44. [PMID: 17694179 PMCID: PMC1937500 DOI: 10.1172/jci31060] [Citation(s) in RCA: 327] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2006] [Accepted: 05/14/2007] [Indexed: 01/08/2023] Open
Abstract
Loss of cardiac myocytes in heart failure is thought to occur largely through an apoptotic process. Here we show that heart failure can also be precipitated through myocyte necrosis associated with Ca2+ overload. Inducible transgenic mice with enhanced sarcolemmal L-type Ca2+ channel (LTCC) activity showed progressive myocyte necrosis that led to pump dysfunction and premature death, effects that were dramatically enhanced by acute stimulation of beta-adrenergic receptors. Enhanced Ca2+ influx-induced cellular necrosis and cardiomyopathy was prevented with either LTCC blockers or beta-adrenergic receptor antagonists, demonstrating a proximal relationship among beta-adrenergic receptor function, Ca2+ handling, and heart failure progression through necrotic cell loss. Mechanistically, loss of cyclophilin D, a regulator of the mitochondrial permeability transition pore that underpins necrosis, blocked Ca2+ influx-induced necrosis of myocytes, heart failure, and isoproterenol-induced premature death. In contrast, overexpression of the antiapoptotic factor Bcl-2 was ineffective in mitigating heart failure and death associated with excess Ca2+ influx and acute beta-adrenergic receptor stimulation. This paradigm of mitochondrial- and necrosis-dependent heart failure was also observed in other mouse models of disease, which supports the concept that heart failure is a pleiotropic disorder that involves not only apoptosis, but also necrotic loss of myocytes in association with dysregulated Ca2+ handling and beta-adrenergic receptor signaling.
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MESH Headings
- Adrenergic beta-2 Receptor Antagonists
- Animals
- Calcium/metabolism
- Calcium Channels, L-Type/genetics
- Calcium Channels, L-Type/metabolism
- Cardiomyopathies/genetics
- Cardiomyopathies/metabolism
- Cardiomyopathies/pathology
- Cyclin D
- Cyclins/metabolism
- Disease Models, Animal
- Gene Expression Regulation
- Heart Failure/genetics
- Heart Failure/metabolism
- Heart Failure/pathology
- Heart Failure/prevention & control
- Mice
- Mice, Transgenic
- Mitochondria, Heart/metabolism
- Myocytes, Cardiac/metabolism
- Myocytes, Cardiac/pathology
- Necrosis/genetics
- Necrosis/metabolism
- Necrosis/pathology
- Receptors, Adrenergic, beta-2/genetics
- Receptors, Adrenergic, beta-2/metabolism
- Survival Rate
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Affiliation(s)
- Hiroyuki Nakayama
- Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA.
Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania, USA.
Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA.
James H. Quillen School of Medicine, East Tennessee State University, and James H. Quillen Veterans Affairs Medical Center, Johnson City, Tennessee, USA
| | - Xiongwen Chen
- Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA.
Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania, USA.
Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA.
James H. Quillen School of Medicine, East Tennessee State University, and James H. Quillen Veterans Affairs Medical Center, Johnson City, Tennessee, USA
| | - Christopher P. Baines
- Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA.
Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania, USA.
Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA.
James H. Quillen School of Medicine, East Tennessee State University, and James H. Quillen Veterans Affairs Medical Center, Johnson City, Tennessee, USA
| | - Raisa Klevitsky
- Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA.
Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania, USA.
Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA.
James H. Quillen School of Medicine, East Tennessee State University, and James H. Quillen Veterans Affairs Medical Center, Johnson City, Tennessee, USA
| | - Xiaoying Zhang
- Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA.
Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania, USA.
Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA.
James H. Quillen School of Medicine, East Tennessee State University, and James H. Quillen Veterans Affairs Medical Center, Johnson City, Tennessee, USA
| | - Hongyu Zhang
- Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA.
Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania, USA.
Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA.
James H. Quillen School of Medicine, East Tennessee State University, and James H. Quillen Veterans Affairs Medical Center, Johnson City, Tennessee, USA
| | - Naser Jaleel
- Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA.
Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania, USA.
Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA.
James H. Quillen School of Medicine, East Tennessee State University, and James H. Quillen Veterans Affairs Medical Center, Johnson City, Tennessee, USA
| | - Balvin H.L. Chua
- Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA.
Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania, USA.
Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA.
James H. Quillen School of Medicine, East Tennessee State University, and James H. Quillen Veterans Affairs Medical Center, Johnson City, Tennessee, USA
| | - Timothy E. Hewett
- Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA.
Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania, USA.
Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA.
James H. Quillen School of Medicine, East Tennessee State University, and James H. Quillen Veterans Affairs Medical Center, Johnson City, Tennessee, USA
| | - Jeffrey Robbins
- Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA.
Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania, USA.
Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA.
James H. Quillen School of Medicine, East Tennessee State University, and James H. Quillen Veterans Affairs Medical Center, Johnson City, Tennessee, USA
| | - Steven R. Houser
- Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA.
Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania, USA.
Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA.
James H. Quillen School of Medicine, East Tennessee State University, and James H. Quillen Veterans Affairs Medical Center, Johnson City, Tennessee, USA
| | - Jeffery D. Molkentin
- Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA.
Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania, USA.
Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA.
James H. Quillen School of Medicine, East Tennessee State University, and James H. Quillen Veterans Affairs Medical Center, Johnson City, Tennessee, USA
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194
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Hool LC. What Cardiologists Should Know About Calcium Ion Channels and Their Regulation by Reactive Oxygen Species. Heart Lung Circ 2007; 16:361-72. [PMID: 17353151 DOI: 10.1016/j.hlc.2007.01.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2006] [Accepted: 01/16/2007] [Indexed: 12/17/2022]
Abstract
Ion channels underlie the electrical activity of cells. Calcium channels have a unique functional role, because not only do they participate in this activity, they form the means by which electrical signals are converted to responses within the cell. Calcium channels play an integral role in excitation in the heart and shaping the cardiac action potential. In addition, calcium influx through calcium channels is responsible for initiating contraction. Abnormalities in calcium homeostasis underlie cardiac arrhythmia, contractile dysfunction and cardiac remodelling. Reactive oxygen species participate in the development of pathology by altering the redox state of regulatory proteins. There is now good evidence that reactive oxygen species regulate the function of calcium channels. In this mini-review, the evidence for regulation of calcium channels by reactive oxygen species and implications with respect to pathology are presented. Calcium channels may represent a target for intervention during hypoxic trigger of arrhythmia or chronic pathological remodelling.
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Affiliation(s)
- Livia C Hool
- Discipline of Physiology, School of Biomedical, Biomolecular and Chemical Sciences, The University of Western Australia, Crawley, Western Australia.
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195
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Ju YK, Allen DG. Store-operated Ca2+ entry and TRPC expression; possible roles in cardiac pacemaker tissue. Heart Lung Circ 2007; 16:349-55. [PMID: 17822952 DOI: 10.1016/j.hlc.2007.07.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2006] [Accepted: 07/09/2007] [Indexed: 11/25/2022]
Abstract
Store-operated Ca(2+) channels (SOCCs) were first identified in non-excitable cells by the observation that depletion of Ca(2+) stores caused increased influx of extracellular Ca(2+). Recent studies have suggested that SOCCs might be related to the transient receptor potential (TRPC) gene family. The mechanism of cardiac pacemaking involves voltage-dependent pacemaker current; in addition there is growing evidence that intracellular sarcoplasmic reticulum (SR) Ca(2+) release plays an important role. In the present short review we assess preliminary evidence for Ca(2+) entry related to SR store depletion and expression of TRPCs in pacemaker tissue. These newer findings suggest that Ca(2+) entry and inward current triggered by store depletion might also contribute to the pacemaker current. Many hormones, drugs and interventions such as ischaemia and stretch, which alter Ca(2+) handling, will also modulate pacemaker firing thought their effect on SOCCs.
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Affiliation(s)
- Yue-kun Ju
- School of Medical Sciences (F13), University of Sydney, Sydney, NSW 2006, Australia.
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196
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Kraft R. The Na+/Ca2+ exchange inhibitor KB-R7943 potently blocks TRPC channels. Biochem Biophys Res Commun 2007; 361:230-6. [PMID: 17658472 DOI: 10.1016/j.bbrc.2007.07.019] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2007] [Accepted: 07/06/2007] [Indexed: 10/23/2022]
Abstract
Na(+)/Ca(2+) exchangers (NCXs) and members of the canonical transient receptor potential (TRPC) channels play an important role in Ca(2+) homeostasis in heart and brain. With respect to their overlapping expression and their role as physiological Ca(2+) influx pathways a functional discrimination of both mechanisms seems to be necessary. Here, the effect of the reverse-mode NCX inhibitor KB-R7943 was investigated on different TRPC channels heterologously expressed in HEK293 cells. In patch-clamp recordings KB-R7943 potently blocked currents through TRPC3 (IC(50)=0.46 microM), TRPC6 (IC(50)=0.71 microM), and TRPC5 (IC(50)=1.38 microM). 1-Oleoyl-2-acetyl-sn-glycerol-induced Ca(2+) entry was nearly completely suppressed by 10 microM KB-R7943 in TRPC6-transfected cells. Thus, KB-R7943 is able to block receptor-operated TRP channels at concentrations which are equal or below those required to inhibit reverse-mode NCX activity. These data further suggest that the protective effects of KB-R7943 in ischemic tissue may, at least partly, be due to inhibition of TRPC channels.
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Affiliation(s)
- Robert Kraft
- Carl-Ludwig-Institute for Physiology, University Leipzig, Liebigstr. 27, 04103 Leipzig, Germany.
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197
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Brenner JS, Dolmetsch RE. TrpC3 regulates hypertrophy-associated gene expression without affecting myocyte beating or cell size. PLoS One 2007; 2:e802. [PMID: 17726532 PMCID: PMC1950081 DOI: 10.1371/journal.pone.0000802] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2007] [Accepted: 07/21/2007] [Indexed: 11/19/2022] Open
Abstract
Pathological cardiac hypertrophy is associated with an increased risk of heart failure and cardiovascular mortality. Calcium (Ca2+) -regulated gene expression is essential for the induction of hypertrophy, but it is not known how myocytes distinguish between the Ca2+ signals that regulate contraction and those that lead to cardiac hypertrophy. We used in vitro neonatal rat ventricular myocytes to perform an RNA interference (RNAi) screen for ion channels that mediate Ca2+-dependent gene expression in response to hypertrophic stimuli. We identified several ion channels that are linked to hypertrophic gene expression, including transient receptor potential C3 (TrpC3). RNAi-mediated knockdown of TrpC3 decreases expression of hypertrophy-associated genes such as the A- and B-type natriuretic peptides (ANP and BNP) in response to numerous hypertrophic stimuli, while TrpC3 overexpression increases BNP expression. Furthermore, stimuli that induce hypertrophy dramatically increase TrpC3 mRNA levels. Importantly, whereas TrpC3-knockdown strongly reduces gene expression associated with hypertrophy, it has a negligible effect on cell size and on myocyte beating. These results suggest that Ca2+ influx through TrpC3 channels increases transcription of genes associated with hypertrophy but does not regulate the signaling pathways that control cell size or contraction. Thus TrpC3 may represent an important therapeutic target for the treatment of cardiac hypertrophy and heart failure.
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Affiliation(s)
- Jacob S. Brenner
- Program in Chemical and Systems Biology, Stanford University, Stanford, California, United States of America
- Department of Neurobiology, Stanford University, Stanford, California, United States of America
| | - Ricardo E. Dolmetsch
- Department of Neurobiology, Stanford University, Stanford, California, United States of America
- * To whom correspondence should be addressed. E-mail:
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198
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Nishida M, Onohara N, Sato Y, Suda R, Ogushi M, Tanabe S, Inoue R, Mori Y, Kurose H. Galpha12/13-mediated up-regulation of TRPC6 negatively regulates endothelin-1-induced cardiac myofibroblast formation and collagen synthesis through nuclear factor of activated T cells activation. J Biol Chem 2007; 282:23117-28. [PMID: 17533154 DOI: 10.1074/jbc.m611780200] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Sustained elevation of [Ca(2+)](i) has been implicated in many cellular events. We previously reported that alpha subunits of G(12) family G proteins (Galpha(12/13)) participate in sustained Ca(2+) influx required for the activation of nuclear factor of activated T cells (NFAT), a Ca(2+)-responsive transcriptional factor, in rat neonatal cardiac fibroblasts. Here, we demonstrate that Galpha(12/13)-mediated up-regulation of canonical transient receptor potential 6 (TRPC6) channels participates in sustained Ca(2+) influx and NFAT activation by endothelin (ET)-1 treatment. Expression of constitutively active Galpha(12) or Galpha(13) increased the expression of TRPC6 proteins and basal Ca(2+) influx activity. The treatment with ET-1 increased TRPC6 protein levels through Galpha(12/13), reactive oxygen species, and c-Jun N-terminal kinase (JNK)-dependent pathways. NFAT is activated by sustained increase in [Ca(2+)](i) through up-regulated TRPC6. A Galpha(12/13)-inhibitory polypeptide derived from the regulator of the G-protein signaling domain of p115-Rho guanine nucleotide exchange factor and a JNK inhibitor, SP600125, suppressed the ET-1-induced increase in expression of marker proteins of myofibroblast formation through a Galpha(12/13)-reactive oxygen species-JNK pathway. The ET-1-induced myofibroblast formation was suppressed by overexpression of TRPC6 and CA NFAT, whereas it was enhanced by TRPC6 small interfering RNAs and cyclosporine A. These results suggest two opposite roles of Galpha(12/13) in cardiac fibroblasts. First, Galpha(12/13) mediate ET-1-induced myofibroblast formation. Second, Galpha(12/13) mediate TRPC6 up-regulation and NFAT activation that negatively regulates ET-1-induced myofibroblast formation. Furthermore, TRPC6 mediates hypertrophic responses in cardiac myocytes but suppresses fibrotic responses in cardiac fibroblasts. Thus, TRPC6 mediates opposite responses in cardiac myocytes and fibroblasts.
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Affiliation(s)
- Motohiro Nishida
- Department of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Fukuoka 812-8582, Japan
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199
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McKinsey TA, Kass DA. Small-molecule therapies for cardiac hypertrophy: moving beneath the cell surface. Nat Rev Drug Discov 2007; 6:617-35. [PMID: 17643091 DOI: 10.1038/nrd2193] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Pathological stress from cardiovascular disease stimulates hypertrophy of heart cells, which increases the risk of cardiac morbidity and mortality. Recent evidence has indicated that inhibiting such hypertrophy could be beneficial, encouraging drug discovery and development efforts for agents that could achieve this goal. Most existing therapies that have antihypertrophic effects target outside-in signalling in cardiac cells, but their effectiveness seems limited, and so attention has recently turned to the potential of targeting intracellular signalling pathways. Here, we focus on new developments with small-molecule inhibitors of cardiac hypertrophy, summarizing both agents that have been in or are poised for clinical testing, and pathways that offer further promising potential therapeutic targets.
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Affiliation(s)
- Timothy A McKinsey
- Gilead Colorado, Inc., 7575 West 103rd Avenue, Westminster, Colorado 80021, USA.
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200
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Ambudkar IS, Ong HL, Liu X, Bandyopadhyay BC, Bandyopadhyay B, Cheng KT. TRPC1: The link between functionally distinct store-operated calcium channels. Cell Calcium 2007; 42:213-23. [PMID: 17350680 DOI: 10.1016/j.ceca.2007.01.013] [Citation(s) in RCA: 155] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2007] [Revised: 01/30/2007] [Accepted: 01/31/2007] [Indexed: 10/23/2022]
Abstract
Although store-operated calcium entry (SOCE) was identified more that two decades ago, understanding the molecular mechanisms that regulate and mediate this process continue to pose a major challenge to investigators in this field. Thus, there has been major focus on determining which of the models proposed for this mechanism is valid and conclusively establishing the components of the store-operated calcium (SOC) channel(s). The transient receptor potential canonical (TRPC) proteins have been suggested as candidate components of the elusive store-operated Ca(2+) entry channel. While all TRPCs are activated in response to agonist-stimulated phosphatidylinositol 4,5, bisphosphate (PIP(2)) hydrolysis, only some display store-dependent regulation. TRPC1 is currently the strongest candidate component of SOC and is shown to contribute to SOCE in many cell types. Heteromeric interactions of TRPC1 with other TRPCs generate diverse SOC channels. Recent studies have revealed novel components of SOCE, namely the stromal interacting molecule (STIM) and Orai proteins. While STIM1 has been suggested to be the ER-Ca(2+) sensor protein relaying the signal to the plasma membrane for activation of SOCE, Orai1 is reported to be the pore-forming component of CRAC channel that mediates SOCE in T-lymphocytes and other hematopoetic cells. Several studies now demonstrate that TRPC1 also associates with STIM1 suggesting that SOC and CRAC channels are regulated by similar molecular components. Interestingly, TRPC1 is also associated with Orai1 and a TRPC1-Orai1-STIM1 ternary complex contributes to SOC channel function. This review will focus on the diverse SOC channels formed by TRPC1 and the suggestion that TRPC1 might serve as a molecular link that determines their regulation by store-depletion.
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Affiliation(s)
- Indu S Ambudkar
- Secretory Physiology Section, GTTB, NIDCR, NIH, Bethesda, MD 20892, USA.
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