Guangdong Key Laboratory of Genome Stability and Human Disease Prevention, Department of Pathophysiology, School of Medicine, Shenzhen University, Shenzhen, 518000, China.
College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China.
Acta Pharmacol Sin. 2022 Sep;43(9):2340-2350. doi: 10.1038/s41401-022-00870-1. Epub 2022 Feb 21.
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited, lethal ventricular arrhythmia triggered by catecholamines. Mutations in genes that encode cardiac ryanodine receptor (RyR2) and proteins that regulate RyR2 activity cause enhanced diastolic Ca release (leak) through the RyR2 channels, resulting in CPVT. Current therapies for CPVT are limited. We found that Z16b, a meroterpenoid isolated from Ganoderma cochlear, inhibited Ca spark frequency (CaSF) in R2474S/ + cardiomyocytes in a dose-dependent manner, with an IC of 3.2 μM. Z16b also dose-dependently suppressed abnormal post-pacing Ca release events. Intraperitoneal injection (i.p.) of epinephrine and caffeine stimulated sustained ventricular tachycardia in all R2474S/+ mice, while pretreatment with Z16b (0.5 mg/kg, i.p.) prevented ventricular arrhythmia in 9 of 10 mice, and Z16b administration immediately after the onset of VT abolished sVT in 9 of 12 mice. Of translational significance, Z16b significantly inhibited CaSF and abnormal Ca release events in human CPVT iPS-CMs. Mechanistically, Z16b interacts with RyR2, enhancing the "zipping" state of the N-terminal and central domains of RyR2. A molecular docking simulation and point mutation and pulldown assays identified Z16b forms hydrogen bonds with Arg626, His1670, and Gln2126 in RyR2 as a triangle shape that anchors the NTD and CD interaction and thus stabilizes RyR2 in a tight "zipping" conformation. Our findings support that Z16b is a novel RyR2 stabilizer that can prevent CPVT. It may also serve as a lead compound with a new scaffold for the design of safer and more efficient drugs for treating CPVT.
儿茶酚胺多形性室性心动过速 (CPVT) 是一种遗传性致命性室性心律失常，由儿茶酚胺触发。编码心脏兰尼碱受体 (RyR2) 的基因突变和调节 RyR2 活性的蛋白导致 RyR2 通道中舒张期 Ca 释放（泄漏）增强，导致 CPVT。CPVT 的当前治疗方法有限。我们发现，从灵芝中分离出的倍半萜 Z16b 以剂量依赖性方式抑制 R2474S/+ 心肌细胞中的 Ca 火花频率 (CaSF)，IC 为 3.2 μM。Z16b 还剂量依赖性地抑制异常起搏后 Ca 释放事件。腹腔内注射（i.p.）肾上腺素和咖啡因可刺激所有 R2474S/+ 小鼠持续室性心动过速，而 Z16b（0.5 mg/kg，i.p.）预处理可防止 10 只小鼠中的室性心律失常，而 Z16b 在 VT 发作后立即给药可使 12 只小鼠中的 9 只 VT 消失。具有转化意义的是，Z16b 显著抑制了人类 CPVT iPS-CMs 中的 CaSF 和异常 Ca 释放事件。从机制上讲，Z16b 与 RyR2 相互作用，增强 RyR2 的 N 端和中心结构域的“拉链”状态。分子对接模拟和点突变及下拉实验确定 Z16b 以三角形形状与 RyR2 中的 Arg626、His1670 和 Gln2126 形成氢键，该三角形形状固定 NTD 和 CD 相互作用，从而使 RyR2 稳定在紧密的“拉链”构象。我们的研究结果支持 Z16b 是一种新型的 RyR2 稳定剂，可预防 CPVT。它也可能成为一种新型骨架的先导化合物，用于设计治疗 CPVT 的更安全、更有效的药物。
