Investigation on the molecular mechanism regulating endovascular differentiation of extravillous trophoblast

绒毛外滋养层（EVT）细胞在血管生成过程中模仿内皮细胞，诱导螺旋动脉重塑，增加流向绒毛内空间的血流。我们之前已经表明，涉及血管内皮生长因子（VEGF）轴的信号是通过来自细胞外基质的整合素信号传导进行血管内分化所必需的：这是通过使用人EVT细胞系TCL 1来实现的，TCL 1显示出特异性地回忆内皮细胞中的形态学变化的管形成。我们使用DNA微阵列分析来检测常氧下在基质胶上管形成期间TCL 1细胞中基因表达谱的改变。缺氧诱导因子（HIF）1A，HIF 1转录因子的亚基，不仅调节适应性反应缺氧，但也在常氧下的许多细胞功能，上调在此形态变化。HIF 1A诱导VEGF和ITGAV/ITGB 3聚集，已知这些作用对EVT中的细胞存活和血管内分化很重要。通过siRNA或化学方法抑制HIF 1A的表达，可抑制缺氧反应元件的转录活性、VEGF的诱导、ITGAV/ITGB 3的聚集，并抑制微管的形成，提示HIF 1A在调节血管内皮细胞的行为，包括基质胶诱导的血管内分化中起重要作用。

Extravillous trophoblast (EVT) cells mimic endothelial cells during angiogenesis, inducing remodeling of the spiral arteries that increases blood flow toward the intravillous space. We have previously shown that signals involving the vascular endothelial growth factor (VEGF) axis are essential for endovascular differentiation through integrin signaling from the extracellular matrix: This was accomplished with use of the human EVT cell line TCL1, which shows tube formation that specifically recalls morphological changes in endothelial cells.Tb investigate endovascular differentiation in EVT further, we used DNA microarray analysis to examine the alteration in gene expression profile in TCL1 cells during tube formation on matrigel under normoxia. Hypoxia inducible, factor (HIF)1A, a subunit of HIF1 transcription factor that regulates not only adaptive responses to hypoxia, but also many cellular functions under normoxia, was up-regulated during this morphological change. HIF1A induces VEGF and ITGAV/ITGB3 aggregation, actions known to be important for cellular survival and endovascular differentiation in EVT. Inhibition of HIF1A up-regulation using siRNA introduction or chemical inhibition suppressed hypoxia-responsive element transcriptional activity, VEGF induction, ITGAV/ITGB3 aggregation accompanied by the inhibition of tube formation in TCL1 cells.These results suggest that HIF1A has a crucial role in regulating EVT behavior including matrigel-induced endovascular differentiation under normoxia.