機能既知化合物ライブラリーからスクリーニングした新規RyR2阻害薬の抗不整脈作用

• Published in: 日本薬理学会年会要旨集 p. 3-O-107
• Main Authors: 村山, 尚, 武中, 真衣, 石井, 光一郎, 呉林, なごみ, 村越, 伸行, 石上ー湯浅, 磨里, 森, 修一, 森本, 幸生, 児玉, 昌美, 影近, 弘之, 小西, 真人, 櫻井, 隆
• Format: Journal Article
• Language: Japanese
• Published: 公益社団法人 日本薬理学会 2022
• Subjects: arrhythmia; calcium; ryanodine receptor
• ISSN: 2435-4953
• DOI: 10.1254/jpssuppl.95.0_3-O-107

Ryanodine receptor 2 (RyR2) is a Ca2+-release channel on the sarcoplasmic reticulum of cardiomyocyte that plays a central role in cardiac excitation-contraction coupling. Spontaneous Ca2+ release events caused by abnormal hyperactive RyR2 are linked to ventricular arrhythmias in patients with heart failure and catecholaminergic polymorphic ventricular tachycardia (CPVT). To search for novel RyR2 inhibitors from well-characterized drug library, we performed a high-throughput screening using HEK293 cells that stably express WT RyR2 and R-CEPIA1er, a genetically encoded endoplasmic reticulum (ER) Ca2+ indicator. By screening 1,535 compounds, we identified three ones that increased the ER Ca2+ signal greater than 4SD above the mean: chloroxylenol (Clxy), orserinate β-methyl (OBM) and riluzole (Ril). All three compounds increased ER Ca2+ signal and decreased the frequency of spontaneous Ca2+ oscillations dose-dependently in HEK293 cells expressing CPVT-linked mutant RyR2s as well as WT RyR2, which corresponded reduction of the Ca2+-dependent [3H]ryanodine binding. To investigate the drug effects on arrhythmogenic Ca2+ release, we observed Ca2+ signals in cardiomyocytes obtained from Tnnt2 ΔK210 and RYR2 I4093V mice that show Ca2+ waves, sparks and triggered activity frequently. Ril and Clxy suppressed Ca2+ waves without affecting action potential induced Ca2+ transients. These results suggest that the RyR2 inhibitors are promising candidates for novel anti-arrhythmic drugs.