Mutations in JPH2-encoded junctophilin-2 associated with hypertrophic cardiomyopathy in humans
Mutations in JPH2-encoded junctophilin-2 associated with hypertrophic cardiomyopathy in humans
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DOI：
10.1016/j.yjmcc.2007.04.006
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发表时间：
2007-06-01
影响因子：
5
通讯作者：
Ackerman, Michael J.
中科院分区：
文献类型：
--
作者：
Landstrom, Andrew P.;Weisleder, Noah;Ackerman, Michael J.
Junctophilin-2 (JPH2) 是 junctophilins 的心脏特异性成员，是一种新表征的连接膜复合蛋白家族，在物理上接近质膜 L 型钙通道和肌浆网兰尼碱受体（钙诱导的钙释放）方面非常重要。 JPH2 敲除小鼠表现出钙瞬变破坏、连接膜复合物形成改变、心肌病和胚胎致死性。此外，JPH2 基因表达在小鼠心肌病模型中下调。为此，我们探索 JPH2 作为人类肥厚型心肌病 (HCM) 发病机制的新候选基因。利用聚合酶链反应、变性高效液相色谱和直接 DNA 测序，对从 388 名无关 HCM 患者获得的 DNA 进行 JPH2 的全面开放阅读框/剪接位点突变分析。使用免疫细胞化学、细胞形态测量和活细胞共聚焦钙成像对 HCM 相关的 JPH2 突变进行设计和功能表征。在 3/388 名不相关的 HCM 患者中发现了三种新的 HCM 易感性突变：S101R、Y141H 和 S165F，它们定位于关键功能域，并且在 1000 个种族匹配的参考等位基因中不存在。从功能上讲，每个人类突变都会导致（i）junctophilin-2 的蛋白质重组，（ii）细胞内钙信号传导的扰动，以及（iii）显着的心肌细胞增生。分子和功能证据表明，junctophilin-2 缺陷和钙信号传导破坏是 HCM 的一种新致病机制，并将 HCM 确立为第一种与 JPH2 遗传缺陷相关的人类疾病。 JPH2 突变是否会导致对其他心肌病（例如扩张型心肌病）的易感性值得研究。 (C) 2007 Elsevier Inc. 保留所有权利。
Junctophilin-2 (JPH2) is a cardiac specific member of the junctophilins, a newly characterized family of junctional membrane complex proteins important in physically approximating the plasmalemmal L-type calcium channel and the sarcoplasmic reticulum ryanodine receptor for calcium-induced calcium release. JPH2 knockout mice showed disrupted calcium transients, altered junctional membrane complex formation, cardiomyopathy, and embryonic lethality. Furthermore, JPH2 gene expression is down-regulated in murine cardiomyopathy models. To this end, we explored JPH2 as a novel candidate gene for the pathogenesis of hypertrophic cardiomyopathy (HCM) in humans. Using polymerase chain reaction, denaturing high performance liquid chromatography, and direct DNA sequencing, comprehensive open reading frame/splice site mutational analysis of JPH2 was performed on DNA obtained from 388 unrelated patients with HCM. HCM-associated JPH2 mutations were engineered and functionally characterized using immunocytochemistry, cell morphometry measurements, and live cell confocal calcium imaging. Three novel HCM-susceptibility mutations: S101R, Y141H and S165F, which localize to key functional domains, were discovered in 3/388 unrelated patients with HCM and were absent in 1000 ethnic-matched reference alleles. Functionally, each human mutation caused (i) protein reorganization of junctophilin-2, (ii) perturbations in intracellular calcium signaling, and (iii) marked cardiomyocyte hyperplasia. The molecular and functional evidence implicates defective junctophilin-2 and disrupted calcium signaling as a novel pathogenic mechanism for HCM and establishes HCM as the first human disease associated with genetic defects in JPH2. Whether susceptibility for other cardiomyopathies, such as dilated cardiomyopathy, can be conferred by mutations in JPH2 warrants investigation. (C) 2007 Elsevier Inc. All rights reserved.