Lindskog Henrik, Athley Elisabet, Larsson Erik, Lundin Samuel, Hellström Mats, Lindahl Per
Institute of Biomedicine, Department of Medical Biochemistry and Cell Biology, Sahlgrenska Academy, Göteborg University, Göteborg, Sweden.
Arterioscler Thromb Vasc Biol. 2006 Jul;26(7):1457-64. doi: 10.1161/01.ATV.0000222925.49817.17. Epub 2006 Apr 20.
The molecular mechanisms that regulate pericyte differentiation are not well understood, partly because of the lack of well-characterized in vitro systems that model this process. In this article, we develop a mouse embryonic stem (ES) cell-based angiogenesis/vasculogenesis assay and characterize the system for vascular smooth muscle cell (VSMC) and pericyte differentiation.
ES cells that were cultured for 5 days on OP9 stroma cells upregulated their transcription of VSMC and pericyte selective genes. Other SMC marker genes were induced at a later time point, which suggests that vascular SMC/pericyte genes are regulated by a separate mechanism. Moreover, sequence analysis failed to identify any conserved CArG elements in the vascular SMC and pericyte gene promoters, which indicates that serum response factor is not involved in their regulation. Gleevec, a tyrosine kinase inhibitor that blocks platelet-derived growth factor (PDGF) spell-receptor signaling, and a neutralizing antibody against transforming growth factor (TGF) beta1, beta2, and beta3 failed to inhibit the induction of vascular SMC/pericyte genes. Finally, ES-derived vascular sprouts recruited cocultured MEF cells to pericyte-typical locations. The recruited cells activated expression of a VSMC- and pericyte-specific reporter gene.
We conclude that OP9 stroma cells induce pericyte differentiation of cocultured mouse ES cells. The induction of pericyte marker genes is temporally separated from the induction of SMC genes and does not require platelet-derived growth factor B or TGFbeta1 signaling.
调节周细胞分化的分子机制尚未完全明确，部分原因是缺乏能够模拟该过程的、特征明确的体外系统。在本文中，我们开发了一种基于小鼠胚胎干（ES）细胞的血管生成/血管发生检测方法，并对该系统中血管平滑肌细胞（VSMC）和周细胞的分化进行了特征分析。
在OP9基质细胞上培养5天的ES细胞上调了其VSMC和周细胞选择性基因的转录。其他平滑肌细胞标记基因在较晚时间点被诱导，这表明血管平滑肌细胞/周细胞基因受一种独立机制调控。此外序列分析未能在血管平滑肌细胞和周细胞基因启动子中鉴定出任何保守的CArG元件，这表明血清反应因子不参与它们的调控。格列卫（一种阻断血小板衍生生长因子（PDGF）受体信号传导的酪氨酸激酶抑制剂）以及针对转化生长因子（TGF）β1、β2和β3的中和抗体未能抑制血管平滑肌细胞/周细胞基因的诱导。最后，ES来源的血管芽将共培养的MEF细胞招募到周细胞典型位置。被招募的细胞激活了VSMC和周细胞特异性报告基因的表达。
我们得出结论，OP9基质细胞可诱导共培养的小鼠ES细胞发生周细胞分化。周细胞标记基因的诱导在时间上与平滑肌细胞基因的诱导分开，并且不需要血小板衍生生长因子B或TGFβ1信号传导。
