Mutation and dysregulation of the cardiac ryanodine receptor (RyR2) or sarcoplasmic reticulum (SR) calcium release channel contributes directly to catecholaminergic polymorphic ventricular tachycardia (CPVT) and heart failure (HF) in humans. Affected RyRs are more active than normal, leaking Ca from the SR during diastole causing arrhythmias and dysfunction. FKBP12.6 and calmodulin (CaM) are proteins that bind tightly with and may stabilize RyR2. We have developed novel quantitative methods to assess (in adult cardiac myocytes) how FKBP, CaM and other peptides bind to and modulate RyR2 gating, and are structurally positioned on the myocyte RyR2. While FKBP12.6 binds RyR2 with high affinity, it is not a critical RyR2 regulator. Here we examine how CaM binding and altered domain-domain interaction in RyR2 are involved in disease-related RyR2 dysfunction, using fluorescent tagged proteins and novel targeted sensors in adult ventricular myocyte confocal imaging to address 4 aims. We will: 1) Test whether HF-related RyR alterations decrease CaM binding and increase the access of the structural unzipping peptide DPc10. 2) Test whether known RyR inhibitors work on pathological RyR2 by altering FKBP12.6, CaM or DPc10 binding. 3) Measure Cleft [Ca] using novel targeted Ca sensors. 4) Enhance RyR2 structural model by mapping sites of S100A1, CaMKII, IPTx and Sorcin. This is a highly collaborative project between two groups with shared interests in cardiac calcium regulation in HF and arrhythmias and with complementary technical expertise in physiology, pharmacology, biochemistry, molecular biology, fluorescence spectroscopy and confocal imaging. This will greatly enhance our understanding of RyR2 structure and function in cardiac myocytes in health and disease and provide novel strategies for the development of therapeutics for pathologically modulated RyR2 in the heart.

Public Health Relevance

Heart failure and arrhythmias are major human health issues, afflicting millions of Americans. It has become clear that leak of calcium from the sarcoplasmic reticulum within the cardiac myocyte between normal heart beats contributes importantly to both of these major cardiac problems. Here we will elucidate the structural and functional problem at the molecular level and develop novel therapeutic strategies.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL092097-07
Application #
9054900
Study Section
Electrical Signaling, Ion Transport, and Arrhythmias Study Section (ESTA)
Program Officer
Lathrop, David A
Project Start
2008-04-01
Project End
2018-04-30
Budget Start
2016-05-01
Budget End
2017-04-30
Support Year
7
Fiscal Year
2016
Total Cost
Indirect Cost
Name
University of California Davis
Department
Pharmacology
Type
Schools of Medicine
DUNS #
047120084
City
Davis
State
CA
Country
United States
Zip Code
95618
Oda, Tetsuro; Yamamoto, Takeshi; Kato, Takayoshi et al. (2018) Nuclear translocation of calmodulin in pathological cardiac hypertrophy originates from ryanodine receptor bound calmodulin. J Mol Cell Cardiol 125:87-97
Hegyi, Bence; Bossuyt, Julie; Griffiths, Leigh G et al. (2018) Complex electrophysiological remodeling in postinfarction ischemic heart failure. Proc Natl Acad Sci U S A 115:E3036-E3044
Liu, Miao; Hoskins, Amanda; Verma, Nirmal et al. (2018) Amylin and diabetic cardiomyopathy - amylin-induced sarcolemmal Ca2+ leak is independent of diabetic remodeling of myocardium. Biochim Biophys Acta Mol Basis Dis 1864:1923-1930
Stroik, Daniel R; Yuen, Samantha L; Janicek, Kevyn A et al. (2018) Targeting protein-protein interactions for therapeutic discovery via FRET-based high-throughput screening in living cells. Sci Rep 8:12560
Galice, Samuel; Xie, Yuanfang; Yang, Yi et al. (2018) Size Matters: Ryanodine Receptor Cluster Size Affects Arrhythmogenic Sarcoplasmic Reticulum Calcium Release. J Am Heart Assoc 7:
Hegyi, Bence; Bossuyt, Julie; Ginsburg, Kenneth S et al. (2018) Altered Repolarization Reserve in Failing Rabbit Ventricular Myocytes: Calcium and ?-Adrenergic Effects on Delayed- and Inward-Rectifier Potassium Currents. Circ Arrhythm Electrophysiol 11:e005852
Yan, Jiajie; Zhao, Weiwei; Thomson, Justin K et al. (2018) Stress Signaling JNK2 Crosstalk With CaMKII Underlies Enhanced Atrial Arrhythmogenesis. Circ Res 122:821-835
Bartos, Daniel C; Morotti, Stefano; Ginsburg, Kenneth S et al. (2017) Quantitative analysis of the Ca2+ -dependent regulation of delayed rectifier K+ current IKs in rabbit ventricular myocytes. J Physiol 595:2253-2268
Sato, Daisuke; Clancy, Colleen E; Bers, Donald M (2017) Dynamics of sodium current mediated early afterdepolarizations. Heliyon 3:e00388
Lang, Di; Sato, Daisuke; Jiang, Yanyan et al. (2017) Calcium-Dependent Arrhythmogenic Foci Created by Weakly Coupled Myocytes in the Failing Heart. Circ Res 121:1379-1391

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