The overall goal is to elucidate the molecular mechanism of excitation-contraction coupling in normal and diseased cardiac muscle. Based upon the unique distribution of the ryanodine receptor (RyR) mutations reported in some cardiac diseases and the pilot studies, the investigator postulates that these mutable domains constitute interacting domain pairs, and that zipping of such domain pairs closes the calcium channel while unzipping opens the channel. Weakening of the inter-domain interaction will cause an increased tendency of domain unzipping, and hence of channel-opening; this leads to the general syndrome of cardiac disease (i.e. increased cytoplasmic Ca 2+ and cardiac injury). According to the investigator's recent studies, a group of peptides corresponding to various regions of the RyR (designated as domain peptides) serves as a powerful tool to identify and characterize key domains involved in Ca 2+ channel regulation. Such domain peptides will be used to mimic the same type of channel hyper-activation phenomena that occur in diseased channels. Mutated domain peptides will be used as a negative control to test the physiologic significance of the observed hyper-activation effect of the peptides. Localizing the regions of the RyR to which these domain peptides bind by means of site-directed fluorescence labeling will identify the key domain pair. By using a fluorescence probe that has been incorporated into the critical site of the domain pair, the investigator proposes to monitor the zipping/unzipping action of the interacting domains. The investigator and his collaborators will then examine the effects of domain peptides on the cardiac channel at levels ranging from the single molecule (single channel measurements) to the whole cell system (skinned cardiac fibers). Further, in collaboration with a group of researchers working on channel dysfunction in a cardiac hypertrophy animal model, the investigator will examine how the domain zipping/unzipping action is altered in this disease model and how one can pharmacologically control the altered domain and channel functions. The new information derived from this program will permit a better understanding of the fundamental mechanism of cardiac calcium channel regulation as well as the pathogenic mechanism of Ca 2+ channel dysfunction occurring in some cardiac diseases. This program will also provide one with new clues for the method of treatments of diseased cardiac RyR channels.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL072841-02
Application #
6725376
Study Section
Cardiovascular and Pulmonary Research A Study Section (CVA)
Program Officer
Przywara, Dennis
Project Start
2003-04-01
Project End
2007-03-31
Budget Start
2004-04-01
Budget End
2005-03-31
Support Year
2
Fiscal Year
2004
Total Cost
$398,360
Indirect Cost
Name
Boston Biomedical Research Institute
Department
Type
DUNS #
058893371
City
Watertown
State
MA
Country
United States
Zip Code
02472
Hino, Akihiro; Yano, Masafumi; Kato, Takayoshi et al. (2012) Enhanced binding of calmodulin to the ryanodine receptor corrects contractile dysfunction in failing hearts. Cardiovasc Res 96:433-43
Gangopadhyay, Jaya P; Ikemoto, Noriaki (2011) Aberrant interaction of calmodulin with the ryanodine receptor develops hypertrophy in the neonatal cardiomyocyte. Biochem J 438:379-87
Suetomi, Takeshi; Yano, Masafumi; Uchinoumi, Hitoshi et al. (2011) Mutation-linked defective interdomain interactions within ryanodine receptor cause aberrant Caýýýýýrelease leading to catecholaminergic polymorphic ventricular tachycardia. Circulation 124:682-94
Gangopadhyay, Jaya Pal; Ikemoto, Noriaki (2010) Intracellular translocation of calmodulin and Ca2+/calmodulin-dependent protein kinase II during the development of hypertrophy in neonatal cardiomyocytes. Biochem Biophys Res Commun 396:515-21
Uchinoumi, Hitoshi; Yano, Masafumi; Suetomi, Takeshi et al. (2010) Catecholaminergic polymorphic ventricular tachycardia is caused by mutation-linked defective conformational regulation of the ryanodine receptor. Circ Res 106:1413-24
Xu, Xiaojuan; Yano, Masafumi; Uchinoumi, Hitoshi et al. (2010) Defective calmodulin binding to the cardiac ryanodine receptor plays a key role in CPVT-associated channel dysfunction. Biochem Biophys Res Commun 394:660-6
Liu, Zheng; Wang, Ruiwu; Tian, Xixi et al. (2010) Dynamic, inter-subunit interactions between the N-terminal and central mutation regions of cardiac ryanodine receptor. J Cell Sci 123:1775-84
Ono, Makoto; Yano, Masafumi; Hino, Akihiro et al. (2010) Dissociation of calmodulin from cardiac ryanodine receptor causes aberrant Ca(2+) release in heart failure. Cardiovasc Res 87:609-17
Hamada, Tomoyo; Gangopadhyay, Jaya P; Mandl, Adel et al. (2009) Defective regulation of the ryanodine receptor induces hypertrophy in cardiomyocytes. Biochem Biophys Res Commun 380:493-7
Tateishi, Hiroki; Yano, Masafumi; Mochizuki, Mamoru et al. (2009) Defective domain-domain interactions within the ryanodine receptor as a critical cause of diastolic Ca2+ leak in failing hearts. Cardiovasc Res 81:536-45

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