Modelling diastolic dysfunction in induced pluripotent stem cell-derived cardiomyocytes from hypertrophic cardiomyopathy patients
Modelling diastolic dysfunction in induced pluripotent stem cell-derived cardiomyocytes from hypertrophic cardiomyopathy patients
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DOI：
10.1093/eurheartj/ehz326
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发表时间：
2019-12-01
影响因子：
39.3
通讯作者：
Wu, Joseph C.
中科院分区：
文献类型：
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作者：
Wu, Haodi;Yang, Huaxiao;Wu, Joseph C.
目的舒张功能障碍（DD）在肥厚性心肌病（HCM）患者中很常见，是主要的发病率和死亡率。然而，其细胞机制尚不完全清楚，目前也没有有效的治疗方法。患者特异性诱导多能干细胞衍生的心肌细胞（iPSC-CMs）在研究HCM中DD的潜在机制和作为药物发现的平台方面具有巨大的潜力。方法和结果在本研究中，健康对照和患有DD的HCM患者产生跳动iPSC-CMs， HCM患者的微型化iPSC-CMs表现出舒张功能受损，表现为舒张时间延长，舒张率降低，舒张肌节长度缩短。比值Ca2+成像显示HCM iPSC-CMs舒张[Ca2+](i)升高和Ca2+处理异常，β -肾上腺素能刺激加剧了这种情况。结合Ca2+成像和牵引力显微镜，我们观察到HCM iPSC-CMs中肌丝Ca2+敏感性增强（以dF/Delta[Ca2+](i)测量）。这些结果被携带HCM突变的基因组编辑的等基因iPSC系证实，表明细胞质舒张Ca2+超载，减慢[Ca2+](i)循环，增加肌丝Ca2+敏感性，共同损害HCM iPSC- cms的松弛。通过部分阻断Ca2+或晚期Na+电流恢复舒张Ca2+稳态，恢复舒张功能，改善长期生存，表明Ca2+信号紊乱是DD的重要细胞病理机制。进一步的研究表明，与对照组iPSC-CMs相比，HCM iPSC-CMs中l型Ca（2+）通道（LTCC）和瞬时受体电位阳离子通道（TRPC）的表达增加，这可能导致舒张[Ca2+](i)过载。综上所述，本研究在单细胞水平上概括了HCM中的DD，并利用iPSC-CMs揭示了DD的新的细胞机制和潜在的治疗靶点。
Aims Diastolic dysfunction (DD) is common among hypertrophic cardiomyopathy (HCM) patients, causing major morbidity and mortality. However, its cellular mechanisms are not fully understood, and presently there is no effective treatment. Patient-specific induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) hold great potential for investigating the mechanisms underlying DD in HCM and as a platform for drug discovery.Methods and results In the present study, beating iPSC-CMs were generated from healthy controls and HCM patients with DD. Micropatterned iPSC-CMs from HCM patients showed impaired diastolic function, as evidenced by prolonged relaxation time, decreased relaxation rate, and shortened diastolic sarcomere length. Ratiometric Ca2+ imaging indicated elevated diastolic [Ca2+](i) and abnormal Ca2+ handling in HCM iPSC-CMs, which were exacerbated by beta-adrenergic challenge. Combining Ca2+ imaging and traction force microscopy, we observed enhanced myofilament Ca2+ sensitivity (measured as dF/Delta[Ca2+](i)) in HCM iPSC-CMs. These results were confirmed with genome-edited isogenic iPSC lines that carry HCM mutations, indicating that cytosolic diastolic Ca2+ overload, slowed [Ca2+](i) recycling, and increased myofilament Ca2+ sensitivity, collectively impairing the relaxation of HCM iPSC-CMs. Treatment with partial blockade of Ca2+ or late Na+ current reset diastolic Ca2+ homeostasis, restored diastolic function, and improved long-term survival, suggesting that disturbed Ca2+ signalling is an important cellular pathological mechanism of DD. Further investigation showed increased expression of L-type Ca(2+)channel (LTCC) and transient receptor potential cation channels (TRPC) in HCM iPSC-CMs compared with control iPSC-CMs, which likely contributed to diastolic [Ca2+](i) overload.Conclusion In summary, this study recapitulated DD in HCM at the single-cell level, and revealed novel cellular mechanisms and potential therapeutic targets of DD using iPSC-CMs.