Investigation on the molecular mechanism regulating endovascular differentiation of extravillous trophoblast

体外滋养细胞（EVT）在血管生成过程中模拟内皮细胞，诱导螺旋动脉的重塑，增加流向静脉内空间的血流量。我们之前已经证明，通过细胞外基质的整合素信号，涉及血管内皮生长因子（VEGF）轴的信号对于血管内分化至关重要：这是通过使用人EVT细胞系TCL1完成的，该细胞系显示了内皮细胞形态变化的管状形成。为了进一步研究EVT血管内分化，我们使用DNA微阵列分析检测了常氧条件下TCL1细胞在基质上形成管过程中基因表达谱的变化。缺氧诱导因子（HIF）1A是HIF1转录因子的一个亚基，它不仅调节对缺氧的适应性反应，还调节正常缺氧下的许多细胞功能，在这种形态变化中上调。HIF1A诱导VEGF和ITGAV/ITGB3聚集，已知这些作用对EVT的细胞存活和血管内分化很重要。在TCL1细胞中，通过siRNA导入或化学抑制HIF1A上调可抑制缺氧反应元件转录活性、VEGF诱导、ITGAV/ITGB3聚集，同时抑制管状形成。这些结果表明，HIF1A在调节EVT行为中起着至关重要的作用，包括在常氧条件下基质诱导的血管内分化。

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.