Free accessResearch articleFirst published online 2005-10
Sarcoplasmic Reticulum Adenosine Triphosphatase Overexpression in the L-type Ca2+ Channel Mouse Results in Cardiomyopathy and Ca2+-Induced Arrhythmogenesis
Background: Overexpression of the L-type voltage-dependent calcium channel α1C-subunit (L-VDCC OE) in transgenic mice results in adaptive hypertrophy followed by a maladaptive phase associated with a decrease in sarcoplasmic reticulum adenosine triphosphatase (SERCA)2a expression at 8 to 10 months of age. Overexpressing SERCA to manipulate calcium (Ca2+) cycling and prevent pathologic phenotypes in some models of heart failure has been proven to be a promising genetic strategy.
Objective: In this study we investigated whether genetic manipulation that increases Ca2+ uptake into the sarcoplasmic reticulum by overexpressing SERCA1a (skeletal muscle specific) into the L-VDCC OE background could restore or further deteriorate Ca2+ cycling, contractile dysfunction, and electrical remodeling in the heart failure phenotype.
Results: We found that the survival rate of L-VDCC OE/SERCA1a OE double transgenic mice decreased by 50%. L-VDCC OE/SERCA1a OE mice displayed an accelerated phenotype of severe dilation of both ventricles associated with deteriorated left ventricular function. Voltage clamp experiments revealed enhanced increased inward Ca2+ current density and decreased the transient outward potassium current. Action potential duration in double transgenic ventricular myocytes was prolonged, and isoproterenol induced early afterdepolarization. These mice demonstrated a high incidence of spontaneous left ventricular arrhythmia. Expression of the proarrhythmic signaling protein Ca2+/calmodulin-dependent kinase II (CaMKII) was increased while connexin43 expression was decreased, defining an important putative mechanism in the electrophysiologic disturbances and mortality.
Conclusions: Despite previous reports of improved cardiac function in heart failure models after SERCA intervention, our results advocate the need to elucidate the involvement of augmented Ca2+ cycling in arrhythmogenesis.
Gwathmey J , Copelas L, MacKinnon R, et al. Abnormal intracellular calcium handling in myocardium from patients with end-stage heart failure. Circ Res61:70-76, 1987
2.
Wehrens X , Marks A. Novel therapeutic approaches for heart failure by normalizing calcium cycling. Nat Rev Drug Discov3:565-573, 2004
3.
del Monte F , Hajjar R. Targeting calcium cycling proteins in heart failure through gene transfer. J Physiol546:49-61, 2002
4.
Chen Y , Escoubet B, Prunier F, et al. Constitutive cardiac overexpression of sarcoplasmic/endoplasmic reticulum Ca2+-ATPase delays myocardial failure after myocardial infarction in rats at a cost of increased acute arrhythmias. Circulation109:1898-1903, 2004
5.
Tweedie D , Harding S, MacLeod K. Sarcoplasmic reticulum Ca content, sarcolemmal Ca influx and the genesis of arrhythmias in isolated guinea-pig cardiomyocytes. J Mol Cell Cardiol32:261-272, 2000
6.
Zarain-Herzberg A , MacLennan D, Periasamy, M. Characterization of rabbit cardiac sarco(endo)plasmic reticulum Ca2(+)-ATPase gene. J Biol Chem265:4670-4677, 1990
7.
Periasamy M , Huke S. SERCA pump level is a critical determinant of Ca(2+)homeostasis and cardiac contractility. J Mol Cell Cardiol33:1053-1063, 2001
8.
Inesi G , Lewis D, Sumbilla C, et al. Cell-specific promoter in adenovirus vector for transgenic expression of SERCA1 ATPase in cardiac myocytes. Am J Physiol274:C645-C653, 1998
9.
Muth J , Yamaguchi H, Mikala G, et al. Cardiac-specific overexpression of the α1 subunit of the L-type voltage-dependent Ca2+ channel in transgenic mice. Loss of isoproterenol-induced contraction. J Biol Chem274:21503-21506, 1999
10.
Muth J , Bodi I, Lewis W, et al. A Ca2+ dependent transgenic model of cardiac hypertrophy: A role for protein kinase Cα. Circulation103:140-147, 2001
11.
Bodi I , Muth J, Hahn H, et al. Electrical remodeling in hearts from a calcium-dependent mouse model of hypertrophy and failure: Complex nature of K+ current changes and action potential duration. J Am Coll Cardiol41:1611-1622, 2003
12.
D’Angelo D , Sakata Y, Lorenz J, et al. Transgenic Gαq overexpression induces cardiac contractile failure in mice. Proc Natl Acad Sci U S A94:8121-8126, 1997
13.
Molkentin J , Lu J, Antos C, et al. A calcineurin-dependent transcriptional pathway for cardiac hypertrophy. Cell93:215-228, 1998
14.
Ji Y , Loukianov E, Loukianova T, et al. SERCA1a can functionally substitute for SERCA2a in the heart. Am J Physiol276:H89-H97, 1999
15.
Lalli M , Yong J, Prasad V, et al. Sarcoplasmic reticulum Ca2+-ATPase (SERCA) 1a structurally substitutes for SERCA2a in the cardiac sarcoplasmic reticulum and increases cardiac Ca2+ handling capacity. Circ Res89:160-167, 2001
16.
Loukianov E , Ji Y, Grupp I, et al. Enhanced myocardial contractility and increased Ca2+ transport function in transgenic hearts expressing the fast-twitch skeletal muscle sarcoplasmic reticulum Ca2+-ATPase. Circ Res83:889-897, 1998
17.
Zhou Y , Wang S, Zhu W, et al. Culture and adenoviral infection of adult mouse cardiac myocytes: Methods for cellular genetic physiology. Am J Physiol Heart Circ Physiol279:H429-H436, 2000
18.
Petrashevskaya N , Bodi I, Rubio M, et al. Cardiac function and electrical remodeling of the calcineurin-overexpressed transgenic mouse. Cardiovasc Res54:117-132, 2002
19.
Wu Y , Temple J, Zhang R, et al. Calmodulin kinase II and arrhythmias in a mouse model of cardiac hypertrophy. Circulation106:1288-1293, 2002
20.
Mitchell G , Jeron A, Koren G. Measurement of heart rate and Q-T interval in the conscious mouse. Am J Physiol274:H747-H751, 1998
21.
Song L , Guia A, Muth J, et al. Ca2+ signaling in cardiac myocytes overexpressing the α1 subunit of L-type Ca2+ channel. Circ Res90:174-181, 2002
22.
Momtaz A , Coulombe A, Richer P, et al. Action potential and plateau ionic currents in moderately and severely DOCA-salt hypertrophied rat hearts. J Mol Cell Cardiol28:2511-2522, 1996
23.
Kaab S , Nuss H, Chiamvimonvat N, et al. Ionic mechanism of action potential prolongation in ventricular myocytes from dogs with pacing-induced heart failure. Circ Res78:262-273, 1996
24.
Beuckelmann D , Nabauer M, Erdmann, E. Intracellular calcium handling in isolated ventricular myocytes from patients with terminal heart failure. Circulation85:1046-1055, 1992
25.
Wolska B , Stojanovic M, Luo W, et al. Effect of ablation of phospholamban on dynamics of cardiac myocyte contraction and intracellular Ca2+. Am J Physiol271:C391-C397, 1996
26.
Zhao W , Frank K, Chu G, et al. Combined phospholamban ablation and SERCA1a overexpression result in a new hyperdynamic cardiac state. Cardiovasc Res57:71-81, 2003
27.
Zhang T , Johnson E, Gu Y, et al. The cardiac-specific nuclear ΔB isoform of Ca2+/calmodulin-dependent protein kinase II induces hypertrophy and dilated cardiomyopathy associated with increased protein phosphatase 2A activity. J Biol Chem277:1261-1267, 2002
28.
Chu G , Carr A, Young K, et al. Enhanced myocyte contractility and Ca2+ handling in a calcineurin transgenic model of heart failure. Cardiovasc Res54:105-116, 2002
29.
Marx S , Reiken S, Hisamatsu Y, et al. PKA phosphorylation dissociates FKBP12.6 from the calcium release channel (ryanodine receptor): Defective regulation in failing hearts. Cell101:365-376, 2000
30.
Santana L , Kranias E, Lederer W. Calcium sparks and excitation-contraction coupling in phospholamban-deficient mouse ventricular myocytes. J Physiol503 (Pt 1):21-29, 1997
31.
Hudmon A , Schulman H. Structure-function of the multi-functional Ca2+/calmodulin-dependent protein kinase II. Biochem J364:593-611, 2002
32.
Anderson M . Calmodulin kinase and L-type calcium channels: A recipe for arrhythmias? Trends Cardiovasc Med14:152-161, 2004
33.
Anderson M , Braun A, Wu Y, et al. KN-93, an inhibitor of multifunctional Ca2+/calmodulin-dependent protein kinase, decreases early afterdepolarizations in rabbit heart. J Pharmacol Exp Ther287:996-1006, 1998
34.
Dzhura I , Wu Y, Colbran R, et al. Calmodulin kinase determines calcium-dependent facilitation of L-type calcium channels. Nat Cell Biol2:173-177, 2000
35.
MacDougall L , Jones L, Cohen P. Identification of the major protein phosphatases in mammalian cardiac muscle which dephosphorylate phospholamban. Eur J Biochem196:725-734, 1991
36.
Neumann J , Maas R, Boknik P, et al. Pharmacological characterization of protein phosphatase activities in preparations from failing human hearts. J Pharmacol Exp Ther289:188-193, 1999
37.
Nakamura K , Robertson M, Liu G, et al. Complete heart block and sudden death in mice overexpressing calreticulin. J Clin Invest107:1245-1253, 2001
38.
Donoghue M , Wakimoto H, Maguire C, et al. Heart block, ventricular tachycardia, and sudden death in ACE2 transgenic mice with downregulated connexins. J Mol Cell Cardiol35:1043-1053, 2003
39.
Dong D , Duan Y, Guo J, et al. Overexpression of calcineurin in mouse causes sudden cardiac death associated with decreased density of K+ channels. Cardiovasc Res57:320-532, 2003
40.
del Monte F , Lebeche D, Guerrero J, et al. Abrogation of ventricular arrhythmias in a model of ischemia and reperfusion by targeting myocardial calcium cycling. Proc Natl Acad Sci U S A101:5622-5727, 2004
41.
O’Donnell J , Sumbilla C, Ma H, et al. Tight control of exogenous SERCA expression is required to obtain acceleration of calcium transients with minimal cytotoxic effects in cardiac myocytes. Circ Res88:415-421, 2001
42.
Teucher N , Prestle J, Seidler T, et al. Excessive sarcoplasmic/endoplasmic reticulum Ca2+-ATPase expression causes increased sarcoplasmic reticulum Ca2+ uptake but decreases myocyte shortening. Circulation110:3553-3559, 2004
