Dantrolene, a Therapeutic Agent for Malignant Hyperthermia, Markedly Improves the Function of Failing Cardiomyocytes by Stabilizing Interdomain Interactions Within the Ryanodine Receptor

JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY

卷:53

Article

Kobayashi, Shigeki¹  Yano, Masafumi¹  Suetomi, Takeshi¹  Ono, Makoto¹  Tateishi, Hiroki¹  Mochizuki, Mamoru¹  Xu, Xiaojuan¹  Uchinoumi, Hitoshi¹  Okuda, Shinichi¹  Yamamoto, Takeshi¹  Koseki, Noritaka²  Kyushiki, Hiroyuki²  Ikemoto, Noriaki³  Matsuzaki, Masunori^1,4 

[1] Yamaguchi Univ, Dept Med & Clin Sci, Div Cardiol, Grad Sch Med, Yamaguchi 7558505, Japan

[2] Otsuka Pharmaceut Co Ltd, Inst New Drug Discovery 1, Tokushima 77101, Japan

[3] Boston Biomed Res Inst, Watertown, MA USA

[4] Harvard Univ, Sch Med, Dept Neurol, Boston, MA 02115 USA

关键词: heart failure;    calcium;    sarcoplasmic reticulum;   

DOI  :  10.1016/j.jacc.2009.01.065

来源: Elsevier

【 摘 要 】

Objectives We sought to investigate the effect of dantrolene, a drug generally used to treat malignant hyperthermia, on the Ca(2+) release and cardiomyocyte function in failing hearts. Background The N-terminal (N: 1-600) and central (C: 2000-2500) domains of the ryanodine receptor (RyR) harbor many mutations associated with malignant hyperthermia in skeletal muscle RyR (RyR1) and polymorphic ventricular tachycardia in cardiac RyR (RyR2). There is strong evidence that interdomain interaction between these regions plays an important role in the mechanism of channel regulation. Methods Sarcoplasmic reticulum vesicles and cardiomyocytes were isolated from the left ventricular muscles of dogs (normal or rapid ventricular pacing for 4 weeks), for Ca(2+) leak, transient, and spark assays. To assess the zipped or unzipped state of the interacting domains, the RyR was labeled fluorescently with methylcoumarin acetate in a site-directed manner. We used a quartz-crystal microbalance technique to identify the dantrolene binding site within the RyR2. Results Dantrolene specifically bound to domain 601-620 in RyR2. In the sarcoplasmic reticulum isolated from pacing-induced failing dog hearts, the defective interdomain interaction (domain unzipping) had already occurred, causing spontaneous Ca(2+) leak. Dantrolene suppressed both domain unzipping and the Ca(2+) leak, demonstrating identical drug concentration-dependence (IC(50) = 0.3 mu mol/l). In failing cardiomyocytes, both diastolic Ca(2+) sparks and delayed afterdepolarization were observed frequently, but 1 mu mol/l dantrolene inhibited both events. Conclusions Dantrolene corrects defective interdomain interactions within RyR2 in failing hearts, inhibits spontaneous Ca(2+) leak, and in turn improves cardiomyocyte function in failing hearts. Thus, dantrolene may have a potential to treat heart failure, specifically targeting the RyR2. (J Am Coll Cardiol 2009; 53: 1993-2005) (C) 2009 by the American College of Cardiology Foundation

【 授权许可】

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