Different populations of cardiovascular progenitor cells have been shown to possess varying differentiation potentials. They have also been used to facilitate heart repair. However, sensitive reporter cell lines that mark the human cardiovascular progenitors are in short supply./nMethods: MESP1 marks the earliest population of cardiovascular progenitor cells during embryo development. Here, we generated a homozygous MESP1 knock-in reporter hESC line where mTomato gene joined to the MESP1 coding region via a 2A peptide, in which both MESP1 alleles were preserved. We performed transcriptome and functional analysis of human MESP1+ cardiovascular progenitor cells and tested their therapeutic potential using a rat model of myocardial infarction./nResults: MESP1-mTomato knock-in reporter faithfully recapitulated the endogenous level of MESP1. Transcriptome analysis revealed that MESP1+ cells highly expressed early cardiovascular genes and heart development genes. The activation of MESP1 relied on the strength of canonical Wnt signaling, peak MESP1-mTomato fluorescence correlated with the window of canonical Wnt inhibition during in vitro differentiation. We further showed that MESP1 bound to the promoter of the WNT5A gene and the up-regulation of WNT5A expression suppressed canonical Wnt/β-CATENIN signaling. Moreover, induced MESP1 expression could substitute the canonical Wnt inhibition step and promote robust cardiomyocyte formation. We used a configurable, chemically defined, tri-lineage differentiation system to obtain cardiomyocytes, endothelial cells, and smooth muscle cells from MESP1+ cells at high efficiency. Finally, we showed that the engraftment of MESP1+ cells repaired rat myocardial infarction model./nConclusions: MESP1-mTomato reporter cells offered a useful platform to study cardiovascular differentiation from human pluripotent stem cells and explore their therapeutic potential in regenerative medicine.

中文翻译：

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纯合MESP1敲入记者hESCs促进心血管细胞分化和心肌梗死修复。

已经显示出不同的心血管祖细胞群具有不同的分化潜能。它们也已用于促进心脏修复。然而，标记人类心血管祖细胞的敏感报告细胞系供不应求。/n方法： MESP1标志着胚胎发育期间最早的心血管祖细胞群。在这里，我们生成了一个纯合的MESP1敲入报告基因hESC系，其中mTomato基因通过2A肽与MESP1编码区相连，其中两个MESP1等位基因均得以保留。我们对人MESP1 +心血管祖细胞进行了转录组和功能分析，并使用大鼠心肌梗死模型测试了其治疗潜力。MESP1-mTomato敲入报告者忠实地概括了MESP1的内源性水平。转录组分析显示，MESP1 +细胞高表达早期心血管基因和心脏发育基因。MESP1的激活依赖于经典Wnt信号的强度，在体外分化过程中，峰值MESP1-mTomato荧光与经典Wnt抑制的窗口相关。我们进一步表明MESP1绑定到WNT5A基因的启动子和WNT5A表达的上调抑制了规范的Wnt /β-CATENIN信号传导。此外，诱导的MESP1表达可以替代经典的Wnt抑制步骤，并促进强劲的心肌细胞形成。我们使用了可配置的，化学定义的三谱系分化系统来获取心肌细胞，内皮细胞，高效地从MESP1 +细胞获得平滑肌细胞。最后，我们证明了MESP1 +细胞的移植修复了大鼠心肌梗死模型。结论： MESP1-mTomato报告细胞为研究人类多能干细胞的心血管分化和探索其在再生医学中的治疗潜力提供了有用的平台。