Department of Developmental Biology, School of Medicine, University of Pittsburgh, 8117 Rangos Research Center, 530 45th Street, Pittsburgh, PA 15201, USA.
J Mol Cell Cardiol. 2013 Oct;63:146-54. doi: 10.1016/j.yjmcc.2013.07.019. Epub 2013 Aug 9.
Early heart development takes place through a complex series of steps, including the induction of cardiac mesoderm, formation of the cardiovascular progenitor cells and the commitment of cardiovascular lineage cells, such as cardiomyocytes (CMs), smooth muscle cells (SMCs) and endothelial cells (ECs). Recently, microRNAs, a family of endogenous, small non-coding RNAs, have been identified as critical regulators in cardiogenesis and cardiovascular disease. Previous studies demonstrated that microRNA-1 (miR-1) could promote cardiac differentiation from mouse and human embryonic stem (ES) cells. However, the underlying mechanism remained largely unclear. We performed microRNA deep sequencing among human ES cells, ES cell derived-multipotent cardiovascular progenitors (MCPs), and MCP-specified CMs, ECs, and SMCs. A specific enrichment of miR-1 was found in CMs, not in SMCs or ECs, implying a key role of miR-1 in determining cardiovascular commitment from MCPs. When overexpressed in human induced pluripotent stem cells, miR-1 enhanced the expression of key cardiac transcriptional factors and sarcomeric genes. Importantly, we found miR-1 promoted CM differentiation and suppressed EC commitment from MCPs by modulating the activities of WNT and FGF signaling pathways. FZD7 and FRS2 were confirmed as miR-1 targets using luciferase reporter assay and western blot. Overall, this study reveals a fate-switching role of miR-1 at early human cardiovascular commitment stage via suppressing both WNT and FGF signaling pathways.
早期心脏发育是通过一系列复杂的步骤进行的，包括心脏中胚层的诱导、心血管祖细胞的形成以及心血管谱系细胞（如心肌细胞[CMs]、平滑肌细胞[SMCs]和内皮细胞[ECs]）的定向分化。最近，miRNA（miRNA）作为一种内源性的小型非编码 RNA，被鉴定为心脏发生和心血管疾病的关键调节因子。先前的研究表明，miR-1 可以促进小鼠和人胚胎干细胞（ES 细胞）的心脏分化。然而，其潜在机制在很大程度上仍不清楚。我们在人 ES 细胞、ES 细胞衍生的多能心血管祖细胞（MCPs）以及 MCP 定向的 CMs、ECs 和 SMCs 中进行了 miRNA 深度测序。在 CMs 中发现 miR-1 的特异性富集，而在 SMCs 或 ECs 中没有，这表明 miR-1 在决定 MCP 向心血管定向分化中起着关键作用。当在人诱导多能干细胞中过表达时，miR-1 增强了关键心脏转录因子和肌节基因的表达。重要的是，我们发现 miR-1 通过调节 WNT 和 FGF 信号通路来促进 CM 分化并抑制 MCP 向 EC 的定向分化。FZD7 和 FRS2 被荧光素酶报告基因检测和 Western blot 证实为 miR-1 的靶标。总之，本研究揭示了 miR-1 在早期人类心血管定向分化阶段通过抑制 WNT 和 FGF 信号通路发挥命运转换作用。
