Department of Molecular Pharmacology & Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, MN, USA.
Department of Molecular Pharmacology & Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, MN, USA; Department of Cardiovascular Medicine, Division of Heart Rhythm Services, Mayo Clinic, Rochester, MN, USA.
Stem Cell Reports. 2023 May 9;18(5):1075-1089. doi: 10.1016/j.stemcr.2023.04.005.
Triadin knockout syndrome (TKOS) is a malignant arrhythmia disorder caused by recessive null variants in TRDN-encoded cardiac triadin. Induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) were generated from two unrelated TKOS patients and an unrelated control. CRISPR-Cas9 gene editing was used to insert homozygous TRDN-p.D18fs13 into a control line to generate a TKOS model (TRDN). Western blot confirmed total knockout of triadin in patient-specific and TRDN iPSC-CMs. iPSC-CMs from both patients revealed a prolonged action potential duration (APD) at 90% repolarization, and this was normalized by protein replacement of triadin. APD prolongation was confirmed in TRDN iPSC-CMs. TRDN iPSC-CMs revealed that loss of triadin underlies decreased expression and co-localization of key calcium handling proteins, slow and decreased calcium release from the sarcoplasmic reticulum, and slow inactivation of the L-type calcium channel leading to frequent cellular arrhythmias, including early and delayed afterdepolarizations and APD alternans.
三联蛋白敲除综合征(Triadin knockout syndrome,TKOS)是一种由 TRDN 编码的心肌三联蛋白隐性纯合缺失变异引起的恶性心律失常疾病。从两名无关 TKOS 患者和一名无关对照中生成诱导多能干细胞衍生的心肌细胞(induced pluripotent stem cell-derived cardiomyocytes,iPSC-CMs)。使用 CRISPR-Cas9 基因编辑将同源 TRDN-p.D18fs13 插入对照系中,以生成 TKOS 模型(TRDN)。Western blot 证实了患者特异性和 TRDN iPSC-CMs 中三联蛋白的完全敲除。两名患者的 iPSC-CMs 均显示复极 90%时动作电位时程(action potential duration,APD)延长,而通过三联蛋白的蛋白替代可使 APD 恢复正常。TRDN iPSC-CMs 证实 APD 延长。TRDN iPSC-CMs 表明,三联蛋白的缺失导致关键钙处理蛋白的表达和共定位减少、肌浆网钙释放缓慢和减少,以及 L 型钙通道失活缓慢,导致频繁的细胞心律失常,包括早期和延迟后除极以及 APD 交替。