最近，美國(guó)桑福德-伯納姆醫(yī)學(xué)研究所和約翰·霍普金斯大學(xué)的研究人員合作,，用一種遺傳性心臟病患者的皮膚細(xì)胞培育出心肌細(xì)胞,，并在培養(yǎng)皿中誘導(dǎo)出心臟病模型，再現(xiàn)了該病發(fā)作時(shí)的主要特征,。研究人員指出,，這一成果有助于人們更好地研究該病，測(cè)試新的治療方法,。相關(guān)論文發(fā)表在1月27日的《自然》（Nature）雜志上,。
這一遺傳性心臟病叫心律失常性右室發(fā)育不良/右室心肌病（ARVD/C）,。大多數(shù)該病患者在20歲之前沒(méi)有征兆,，因此很難研究其進(jìn)展情況和相應(yīng)療法。論文高級(jí)作者,、桑福德-伯納姆醫(yī)學(xué)研究所副教授惠生文森特·陳說(shuō)：“要證明培養(yǎng)皿中的疾病模型和成人患者疾病之間具有臨床相關(guān)性是非常困難的,。ARVD/C癥狀通常到青年期才會(huì)顯出來(lái)，而我們用的干細(xì)胞在性質(zhì)上屬于胚胎,。但我們的研究有一項(xiàng)關(guān)鍵突破,，誘導(dǎo)胚胎細(xì)胞擁有了成人心肌的新陳代謝。”
研究人員先從ARVD/C患者身上采集皮膚細(xì)胞,，這些細(xì)胞含有與該病相關(guān)的遺傳變異,；然后加入某些分子，讓成人皮膚細(xì)胞逆轉(zhuǎn)回到類(lèi)似胚胎狀態(tài),，也就是誘導(dǎo)多能干細(xì)胞（iPSCs）狀態(tài),；再進(jìn)一步誘導(dǎo)iPSCs，使其能無(wú)限供給患者特有的心肌細(xì)胞,。這些心肌細(xì)胞擁有大部分的胚胎性質(zhì),，但同時(shí)又?jǐn)y帶了患者最初的遺傳變異,。
培養(yǎng)皿中處于胚胎階段的ARVD/C心肌細(xì)胞在一年內(nèi)都未顯出任何疾病的跡象。他們用了一些混合物,，誘導(dǎo)心肌細(xì)胞的新陳代謝由胚胎方式轉(zhuǎn)換成成人方式,。新陳代謝成熟是誘導(dǎo)胚胎心肌細(xì)胞產(chǎn)生成人ARVD/C信號(hào)的關(guān)鍵，因?yàn)槿祟?lèi)胎兒心肌細(xì)胞是以葡萄糖為主要能源,，而成人心肌細(xì)胞是用脂肪,。他們還在誘變后的心肌細(xì)胞中發(fā)現(xiàn)了ARVD/C心臟的特征，一種叫做PPAR的蛋白過(guò)度活躍,。
研究人員指出,，新模型在培養(yǎng)皿中再現(xiàn)了這種疾病，為治療該病提供了新的潛在藥物標(biāo)靶,。約翰·霍普金斯大學(xué)醫(yī)學(xué)院遺傳心臟病中心副教授與醫(yī)學(xué)主管丹尼爾·加杰說(shuō)：“目前,，世界上還沒(méi)有預(yù)防ARVD/C發(fā)展的方法，有了這一新模型,，我們希望能對(duì)這種威脅生命的疾病,，開(kāi)發(fā)出更好的治療方法。”(生物谷Bioon.com)
doi:10.1038/nature11799
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Studying arrhythmogenic right ventricular dysplasia with patient-specific iPSCs
Changsung Kim,1 Johnson Wong,1 Jianyan Wen,1, 2 Shirong Wang,1 Cheng Wang,1 Sean Spiering,3 Natalia G. Kan,3 Sonia Forcales,3 Pier Lorenzo Puri,3, 4 Teresa C. Leone,5 Joseph E. Marine,6 Hugh Calkins,6 Daniel P. Kelly,5 Daniel P. Judge6 & Huei-Sheng Vincent Chen1, 7
Cellular reprogramming of somatic cells to patient-specific induced pluripotent stem cells (iPSCs) enables in vitro modelling of human genetic disorders for pathogenic investigations and therapeutic screens1, 2, 3, 4, 5, 6, 7. However, using iPSC-derived cardiomyocytes (iPSC-CMs) to model an adult-onset heart disease remains challenging owing to the uncertainty regarding the ability of relatively immature iPSC-CMs to fully recapitulate adult disease phenotypes. Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is an inherited heart disease characterized by pathological fatty infiltration and cardiomyocyte loss predominantly in the right ventricle8, which is associated with life-threatening ventricular arrhythmias. Over 50% of affected individuals have desmosome gene mutations, most commonly in PKP2, encoding plakophilin-2 (ref. 9). The median age at presentation of ARVD/C is 26 years8. We used previously published methods1, 10 to generate iPSC lines from fibroblasts of two patients with ARVD/C and PKP2 mutations11, 12. Mutant PKP2 iPSC-CMs demonstrate abnormal plakoglobin nuclear translocation and decreased β-catenin activity13 in cardiogenic conditions; yet, these abnormal features are insufficient to reproduce the pathological phenotypes of ARVD/C in standard cardiogenic conditions. Here we show that induction of adult-like metabolic energetics from an embryonic/glycolytic state and abnormal peroxisome proliferator-activated receptor gamma (PPAR-γ) activation underlie the pathogenesis of ARVD/C. By co-activating normal PPAR-alpha-dependent metabolism and abnormal PPAR-γ pathway in beating embryoid bodies (EBs) with defined media, we established an efficient ARVD/C in vitro model within 2 months. This model manifests exaggerated lipogenesis and apoptosis in mutant PKP2 iPSC-CMs. iPSC-CMs with a homozygous PKP2 mutation also had calcium-handling deficits. Our study is the first to demonstrate that induction of adult-like metabolism has a critical role in establishing an adult-onset disease model using patient-specific iPSCs. Using this model, we revealed crucial pathogenic insights that metabolic derangement in adult-like metabolic milieu underlies ARVD/C pathologies, enabling us to propose novel disease-modifying therapeutic strategies.
