Calcium regulation in cardiac myocytes is central to excitation-contraction coupling (ECC) and in mitochondrial and hypertrophic (Hyp) nuclear signaling. Ubiquitous Ca regulatory systems, Ca-calmodulin (CaM) dependent protein kinase II (CaMKll), calcineurin and inositol (1,4,5)P3 receptors (InsP3R) in myocytes have been implicated in altering ECC, arrhythmogenesis and nuclear signaling. This PPG has advanced understanding of these emergent fields during the current award. In this renewal, novel questions &methods will be used to deepen understanding of these areas with respect to ECC, mitochondrial signaling, Hyp &heart failure (HF). Four highly synergistic multidisciplinary projects are planned. Project I (Bers) focuses on critical aspects of cellular CaMKll in aims concerning: 1) acute CaM &CaMKll effects on ECC, 2) Ca/CaM-dependent nuclear signaling via HDAC and NFAT, 3) quantitative aspects of mitochondrial Ca signaling, and 4) altered CaMKll signaling in Hyp &HF (regarding ECC, arrhythmias &nuclear regulation). Project II (Blatter) focuses on cellular aspects of IP3 signaling in 3 aims (?Hyp &HF) concerning: 1) acute IP3R-mediated effects on ECC and arrhythmias, 2) the role of InsP3R in mitochondrial Ca signaling and oxidative stress, and 3) Ca coding and IP3R involvement in nuclear NFAT signaling. Project III (Molkentin) focuses on Ca signaling and hypertrophic signaling and will assess how 1) altered Na influx via Na channels and 2) altered Na efflux via Na/K-ATPase regulate myocyte Ca and Hyp, and 3) how cyclophilin D &permeability transition pore regulate mitochondrial Ca. Project IV (Brown) focuses on CaMKll isoform-specific targets and localization by assessing 1) CaMKIldeltaB(B vs. CaMKIldeltaC(c localization and targets, 2) functional consequences of CaMKll compartmentalization, 3) how CaMKll is involved in post-ischemic signaling and 4) how CaMKll alters mitochondrial function. Scientific cores will support these aims. Core B (Genefic Mouse Models) will develop unique mice (e.g. KO/transgenics for InsP3R, CaMKIIdelta/gamma(, PKD, Epac1/2) for whole animal &myocyte studies. Core C (HF Rabbits) will prepare and do some analysis of HF rabbits. This integrates experienced investigators with highly complementary expertise and perspective to tackle these questions in an interactive multidisciplinary approach. Results will greatly increase our understanding of the roles of CaMKll and InsP3R in cardiac myocytes during ECC, arrhythmogenesis &nuclear signaling in normal, Hyp and HF cardiac myocytes.
Cardiac myocyte calcium signaling is critical to the electrical activity which synchronizes the heartbeat, the contraction that pumps blood, energetic balance at the mitochondrial level, and the control of gene transcription. In heart failure or arrhythmias things go wrong in these pathways, contributing to heart malfunction. Here we will provide novel experimental results in careful quantitative studies, which will help to understand the fundamental workings of these systems critical to health and cardiac disease.
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|Panama, Brian K; Korogyi, Adam S; Aschar-Sobbi, Roozbeh et al. (2016) Reductions in the Cardiac Transient Outward K+ Current Ito Caused by Chronic Î²-Adrenergic Receptor Stimulation Are Partly Rescued by Inhibition of Nuclear Factor ÎºB. 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) CaMKIIÎ´ mediates Î²-adrenergic effects on RyR2 phosphorylation and SR Ca(2+) leak and the pathophysiological response to chronic Î²-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 Î´. J Biol Chem 290:25646-56|
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