Highly efficient derivation of ventricular cardiomyocytes from induced pluripotent stem cells with a distinct epigenetic signature

The generation of sufficient numbers of mature ventricular myocytes for effective cell-based therapy is a central barrier for cardiac regenerative medicine. Here we demonstrate that induced pluripotent stem cells (iPSCs) can be derived from murine ventricular myocytes, and consistent with other reports of iPSCs derived from various somatic cell types, ventricular myocyte derived iPSCs (ViPSCs) exhibit a markedly higher propensity to differentiate into beating cardiomyocytes as compared to genetically-matched embryonic stem cells (ESCs) or iPSCs derived from tail-tip fibroblasts. Strikingly, ViPSC-derived cardiomyocytes form up to 99% ventricular myocytes suggesting that ventricular myocyte-derived iPSCs may be a viable strategy to generate specific cardiomyocyte subtypes for cell-based therapies. The enhanced ventricular myogenesis in ViPSCs is mediated via increased numbers of cardiovascular progenitors at early stages of differentiation. In order to investigate the mechanism of enhanced ventricular myogenesis from ViPSCs, we performed global gene expression and DNA methylation analysis, which revealed a distinct epigenetic signature that may be involved in specifying the ventricular myocyte fate in pluripotent stem cells. Total RNA was extracted from mouse ES cells, tail tip fibroblasts (TTFs), ventricular myocytes (VMs), TTF-derived induced pluripotent stem cells (TiPSCs) and VM-derived induced pluripotent stem cells (ViPSCs). Global gene expression profiling was performed using affymetrix mouse 430 2.0 gene arrays.

为实现有效的细胞治疗，获取足量成熟心室肌细胞是心脏再生医学领域面临的核心障碍。本研究证实，可从小鼠心室肌细胞中诱导获得多能干细胞（induced pluripotent stem cells, iPSCs）；与此前通过多种体细胞制备诱导多能干细胞的相关研究结果一致，心室肌细胞来源的诱导多能干细胞（ViPSCs）相较于遗传背景匹配的胚胎干细胞（embryonic stem cells, ESCs）或尾尖成纤维细胞（tail-tip fibroblasts, TTFs）来源的诱导多能干细胞（TiPSCs），其向搏动性心肌细胞分化的潜能显著更高。尤为值得关注的是，ViPSCs分化获得的心肌细胞中，心室肌细胞占比最高可达99%，这表明心室肌细胞来源的诱导多能干细胞或可成为针对细胞治疗获取特异性心肌细胞亚型的可行方案。ViPSCs所具备的更强心室肌生成能力，是通过分化早期心血管祖细胞数量的增加所介导的。为探究ViPSCs心室肌生成能力增强的分子机制，本研究开展了全基因表达谱与DNA甲基化分析，结果揭示了一种独特的表观遗传特征，该特征或参与调控多能干细胞向心室肌细胞的命运特化。本研究从小鼠ES细胞、尾尖成纤维细胞（TTFs）、心室肌细胞（VMs）、尾尖成纤维细胞来源的诱导多能干细胞（TiPSCs）以及心室肌细胞来源的诱导多能干细胞（ViPSCs）中提取了总RNA，并采用Affymetrix小鼠430 2.0基因芯片完成了全基因表达谱检测。