Myotonic dystrophy type 1 patient-derived iPSCs for the investigation of CTG repeat instability.
Myotonic dystrophy type 1 patient-derived iPSCs for the investigation of CTG repeat instability.
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DOI：
10.1038/srep42522
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发表时间：
2017-02-13
影响因子：
4.6
通讯作者：
Sakurai H
中科院分区：
文献类型：
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作者：
Ueki J;Nakamori M;Nakamura M;Nishikawa M;Yoshida Y;Tanaka A;Morizane A;Kamon M;Araki T;Takahashi MP;Watanabe A;Inagaki N;Sakurai H
强直性肌营养不良 1 型 (DM1) 是一种常染色体显性多系统疾病，由强直性肌营养不良蛋白激酶 (DMPK) 中 CTG 重复序列扩增引起。扩展的 CTG 重复序列不稳定，并且会随着年龄的增长而增加基因长度，从而使症状恶化。为了建立适合重复不稳定性研究的人类干细胞系统，产生了 DM1 患者来源的 iPSC，并分化为 DM1 中常见的三种细胞类型，即心肌细胞、神经元和肌细胞。然后我们精确分析了这些细胞中的CTG重复长度。我们的 DM1-iPSC 显示 CTG 重复序列逐渐延长，而所有细胞系中的重复分布没有变化，具体取决于未分化细胞的传代数量。然而，分化成不同体细胞类型后，平均 CTG 重复长度没有显着变化。我们还使用 ATAC-seq 评估了 DM1-iPSC 中的染色质可及性。 DM1 心肌细胞中的染色质状态在 DMPK 位点以及 SIX5 及其启动子区域是封闭的，而在对照中是开放的，表明表观遗传修饰可能与 DM1 中的 CTG 重复扩增有关。这些发现可能有助于阐明重复不稳定性在 DM1 中 CTG 重复扩增中的作用。
Myotonic dystrophy type 1 (DM1) is an autosomal-dominant multi-system disease caused by expanded CTG repeats in dystrophia myotonica protein kinase (DMPK). The expanded CTG repeats are unstable and can increase the length of the gene with age, which worsens the symptoms. In order to establish a human stem cell system suitable for the investigation of repeat instability, DM1 patient-derived iPSCs were generated and differentiated into three cell types commonly affected in DM1, namely cardiomyocytes, neurons and myocytes. Then we precisely analysed the CTG repeat lengths in these cells. Our DM1-iPSCs showed a gradual lengthening of CTG repeats with unchanged repeat distribution in all cell lines depending on the passage numbers of undifferentiated cells. However, the average CTG repeat length did not change significantly after differentiation into different somatic cell types. We also evaluated the chromatin accessibility in DM1-iPSCs using ATAC-seq. The chromatin status in DM1 cardiomyocytes was closed at the DMPK locus as well as at SIX5 and its promoter region, whereas it was open in control, suggesting that the epigenetic modifications may be related to the CTG repeat expansion in DM1. These findings may help clarify the role of repeat instability in the CTG repeat expansion in DM1.