IPaR-dependent Ca release plays an important role for a wide variety of cardiac functions, including modulation of excitation-contraction coupling (ECC), generation of arrhythmia, modulation of mitochondrial function and regulation of Ca-dependent transcription factors in hypertrophy and hear failure. The overall goal of the proposed study is to 1) identify the mechanisms of IPsR-dependent Ca signaling for diastolic and systolic function, 2) determine the relationship between IPaR-dependent Ca release, mitochondrial Ca uptake and its effect on mitochondrial function, and 3) define the Ca-dependent mechanisms of isoform- and tissuespecific regulation of the hypertrophy transcription factor NFAT.
The specific aims are: 1) test the hypothesis that IP3 receptor (IP3R)-dependent Ca release modulates diastolic (SR Ca leak) and systolic (positive inotropic and proarrhythmic effects) Ca signaling in normal adult myocytes and in cardiac hypertrophy and heart failure; 2) test the hypothesis that IPsR-dependent Ca release enhances mitochondrial Ca uptake and mitochondrial Ca-dependent functions (Ca-dependent hydrogenases and metabolic function;opening of the permeability transition pore;nitric oxide (NO) and ROS production by mitochondrial NOS, leading to altered cellular redox state); 3) identify Ca signaling pathways relevant for the activation of the transcription factor NFAT that initiates hypertrophic remodeling processes, and test the hypothesis that Ca-dependent regulation of NFAT is isoform- (NFATcl vs. NFATc3), tissue- (atrial vs. ventricle) and disease state- (normal vs. heart failure) specific and modulated by the redox state of the cell. To achieve these aims a multitude of experimental techniques will be used: high resolution imaging by laser scanning confocal microscopy in single myocytes to measure whole cell and subcellular [Ca]i, [Cajmito and [Ca]sR, whole-cell voltage and current clamp techniques, subcellular photolysis of caged Ca, adenoviral gene-transfer, and pharmacological manipulation of Ca transport and buffering. Experiments will be conducted on adult myocytes from wild-type mouse and rabbit, heart failure rabbit, and transgenic mouse models. The proposed research will provide fundamental new information on the cellular mechanism of Ca signaling relevant to the understanding of cardiac hypertrophy and failure.

Public Health Relevance

Cardiovascular diseases, including cardiac hypertrophy and failure, dre among the leading causes of morbidity and mortality, and are responsible for a significant portion of health related costs. This study seeks to investigate, at the cellular level, the specific disturbances in cellular calcium homeostasis of the diseased heart that ultimately result in failing heart function, and to elucidate the mechanisms and signaling pathways that result in the structural and functional changes typical for the hypertrophic and failing heart.

National Institute of Health (NIH)
National Heart, Lung, and Blood Institute (NHLBI)
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Heart, Lung, and Blood Initial Review Group (HLBP)
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University of California Davis
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Hoeker, Gregory S; Hanafy, Mohamed A; Oster, Robert A et al. (2016) Reduced Arrhythmia Inducibility With Calcium/Calmodulin-dependent Protein Kinase II Inhibition in Heart Failure Rabbits. J Cardiovasc Pharmacol 67:260-5
Panama, Brian K; Korogyi, Adam S; Aschar-Sobbi, Roozbeh et al. (2016) Reductions in the Cardiac Transient Outward K+ Current Ito Caused by Chronic β-Adrenergic Receptor Stimulation Are Partly Rescued by Inhibition of Nuclear Factor κB. J Biol Chem 291:4156-65
Lu, Xiyuan; Kwong, Jennifer Q; Molkentin, Jeffery D et al. (2016) Individual Cardiac Mitochondria Undergo Rare Transient Permeability Transition Pore Openings. Circ Res 118:834-41
Uchinoumi, Hitoshi; Yang, Yi; Oda, Tetsuro et al. (2016) CaMKII-dependent phosphorylation of RyR2 promotes targetable pathological RyR2 conformational shift. J Mol Cell Cardiol 98:62-72
Kanaporis, Giedrius; Blatter, Lothar A (2016) Calcium-activated chloride current determines action potential morphology during calcium alternans in atrial myocytes. J Physiol 594:699-714
Miyamoto, Shigeki; Brown, Joan Heller (2016) Drp1 and Mitochondrial Autophagy Lend a Helping Hand in Adaptation to Pressure Overload. Circulation 133:1225-7
Bossuyt, Julie; Bers, Donald M (2015) Assessing GPCR and G protein signaling to the nucleus in live cells using fluorescent biosensors. Methods Mol Biol 1234:149-59
Grimm, Michael; Ling, Haiyun; Willeford, Andrew et al. (2015) CaMKIIδ mediates β-adrenergic effects on RyR2 phosphorylation and SR Ca(2+) leak and the pathophysiological response to chronic β-adrenergic stimulation. J Mol Cell Cardiol 85:282-91
Hohendanner, Felix; Maxwell, Joshua T; Blatter, Lothar A (2015) Cytosolic and nuclear calcium signaling in atrial myocytes: IP3-mediated calcium release and the role of mitochondria. Channels (Austin) 9:129-38
Erickson, Jeffrey R; Nichols, C Blake; Uchinoumi, Hitoshi et al. (2015) S-Nitrosylation Induces Both Autonomous Activation and Inhibition of Calcium/Calmodulin-dependent Protein Kinase II δ. J Biol Chem 290:25646-56

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