RRAD mutation causes electrical and cytoskeletal defects in cardiomyocytes derived from a familial case of Brugada syndrome
RRAD mutation causes electrical and cytoskeletal defects in cardiomyocytes derived from a familial case of Brugada syndrome
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DOI：
10.1093/eurheartj/ehz308
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发表时间：
2019-10-01
影响因子：
39.3
通讯作者：
Le Scouarnec, Solena
中科院分区：
文献类型：
--
作者：
Belbachir, Nadjet;Portero, Vincent;Le Scouarnec, Solena
Brugada综合征（BrS）是一种易发生室性心律失常的遗传性心脏病。尽管付出了相当大的努力，但其遗传基础和细胞机制仍然在很大程度上未知。本研究的目的是确定一个新的易感基因BrS通过家族investigation.Methods和结果全外显子组测序进行了三代系谱与五个受影响的成员允许识别一个罕见的非同义取代（P.R211H）在RRAD，基因编码的RAD GTdR，携带的所有受影响的家庭成员。在3/186例不相关的索引病例中发现了另外三种罕见的错义变体。我们检测到更高水平的RRAD转录物在心外膜下比在人心脏的心内膜下，并在右心室流出道相比，在小鼠的其他心脏隔室。然后在源自诱导多能干细胞（iPSC-CM）的人心肌细胞中对p.R211H变体进行电生理学和结构研究。来自两个受影响家族成员的诱导多能干细胞衍生的心肌细胞表现出动作电位上升速度降低，动作电位延长和早期后除极发生率增加，Na+峰电流幅度降低和Na+持续电流幅度增加，以及肌动蛋白分布异常和局灶性粘连较少，通过基因组编辑在对照iPSC中插入p.R211H-RRAD变体证实了这些结果。结论本研究发现了一个潜在的新的BrS易感基因RRAD。来自诱导多能干细胞表达RRAD变体的心肌细胞概括了BrS的单细胞电生理学特征，包括改变的Na+电流以及细胞骨架紊乱。
Aims The Brugada syndrome (BrS) is an inherited cardiac disorder predisposing to ventricular arrhythmias. Despite considerable efforts, its genetic basis and cellular mechanisms remain largely unknown. The objective of this study was to identify a new susceptibility gene for BrS through familial investigation.Methods and results Whole-exome sequencing performed in a three-generation pedigree with five affected members allowed the identification of one rare non-synonymous substitution (p.R211H) in RRAD, the gene encoding the RAD GTPase, carried by all affected members of the family. Three additional rare missense variants were found in 3/186 unrelated index cases. We detected higher levels of RRAD transcripts in subepicardium than in subendocardium in human heart, and in the right ventricle outflow tract compared to the other cardiac compartments in mice. The p.R211H variant was then subjected to electrophysiological and structural investigations in human cardiomyocytes derived from induced pluripotent stem cells (iPSC-CMs). Cardiomyocytes derived from induced pluripotent stem cells from two affected family members exhibited reduced action potential upstroke velocity, prolonged action potentials and increased incidence of early after depolarizations, with decreased Na+ peak current amplitude and increased Na+ persistent current amplitude, as well as abnormal distribution of actin and less focal adhesions, compared with intra-familial control iPSC-CMs Insertion of p.R211H-RRAD variant in control iPSCs by genome editing confirmed these results. In addition, iPSC-CMs from affected patients exhibited a decreased L-type Ca2+ current amplitude.Conclusion This study identified a potential new BrS-susceptibility gene, RRAD. Cardiomyocytes derived from induced pluripotent stem cells expressing RRAD variant recapitulated single-cell electrophysiological features of BrS, including altered Na+ current, as well as cytoskeleton disturbances.