Siu Chung-Wah, Lee Yee-Ki, Ho Jenny Chung-Yee, Lai Wing-Hon, Chan Yau-Chi, Ng Kwong-Man, Wong Lai-Yung, Au Ka-Wing, Lau Yee-Man, Zhang Jinqiu, Lay Kenneth Weijian, Colman Alan, Tse Hung-Fat
Cardiology Division, Department of Medicine, Queen Mary Hospital, the University of Hong Kong, Hong Kong SAR, China.
Aging (Albany NY). 2012 Nov;4(11):803-822. doi: 10.18632/aging.100503.
We identified an autosomal dominant non‐sense mutation (R225X) in exon 4 of the lamin A/C (LMNA) gene in a Chinese family spanning 3 generations with familial dilated cardiomyopathy (DCM). In present study, we aim to generate induced pluripotent stem cells derived cardiomyocytes (iPSC‐CMs) from an affected patient with R225X and another patient bearing LMNA frame‐shift mutation for drug screening.
Higher prevalence of nuclear bleb formation and micronucleation was present in LMNA(R225X/WT) and LMNA(Framshift/WT) iPSC‐CMs. Under field electrical stimulation, percentage of LMNA‐mutated iPSC‐CMs exhibiting nuclear senescence and cellular apoptosis markedly increased. shRNA knockdown of LMNA replicated those phenotypes of the mutated LMNA field electrical stress. Pharmacological blockade of ERK1/2 pathway with MEK1/2 inhibitors, U0126 and selumetinib (AZD6244) significantly attenuated the pro‐apoptotic effects of field electric stimulation on the mutated LMNA iPSC‐CMs.
LMNA‐related DCM was modeled in‐vitro using patient‐specific iPSC‐CMs. Our results demonstrated that haploinsufficiency due to R225X LMNA non‐sense mutation was associated with accelerated nuclear senescence and apoptosis of iPSC‐ CMs under electrical stimulation, which can be significantly attenuated by therapeutic blockade of stress‐related ERK1/2 pathway.
我们在一个三代相传的患有家族性扩张型心肌病(DCM)的中国家系中,鉴定出了核纤层蛋白A/C(LMNA)基因第4外显子的一个常染色体显性无义突变(R225X)。在本研究中,我们旨在从一名携带R225X突变的患病患者以及另一名携带LMNA移码突变的患者中获取诱导多能干细胞衍生的心肌细胞(iPSC-CMs)用于药物筛选。
在LMNA(R225X/WT)和LMNA(移码突变/WT)iPSC-CMs中,核泡形成和微核形成的发生率更高。在电场刺激下,表现出核衰老和细胞凋亡的LMNA突变iPSC-CMs的百分比显著增加。通过短发夹RNA敲低LMNA可重现突变型LMNA电场应激的那些表型。用MEK1/2抑制剂U0126和司美替尼(AZD6244)对ERK1/2通路进行药理学阻断,可显著减弱电场刺激对突变型LMNA iPSC-CMs的促凋亡作用。
利用患者特异性iPSC-CMs在体外构建了与LMNA相关的DCM模型。我们的结果表明,R225X LMNA无义突变导致的单倍剂量不足与电刺激下iPSC-CMs的核衰老加速和凋亡有关,而应激相关的ERK1/2通路的治疗性阻断可显著减弱这种情况。