Molecular mechanism of vascular formation

(1)瞬时过表达转录因子Ets 1可促进内皮细胞凋亡。Ets 1使促凋亡Bid、细胞色素p450、caspase-4、p27和p21的表达增加2倍以上，而使抗凋亡DAD-1、AXL、考克斯-2、IAP-2和MDM-2的表达降低小于0. 5倍于ECs。(2)VEGF在大血管内皮细胞和小血管内皮细胞中的信号转导途径不同。尤其是Ras在小血管内皮细胞中起重要作用。(3)转基因小鼠实验表明，VEGF家族的新成员VEGF-E可促进血管新生，但无血管通透性。(4)VEGFR-2（KDR）自身磷酸化位点为1175 Y和1214 Y。PLC-γ的羧基端SH 2结构域与磷酸化的1214 Y结合，这是MAPK激活和DNA合成增加所必需的。(5)MadCAM-1在胚胎早期的静脉内皮细胞中特异性表达。BMP-4增加MadCAM-1阳性静脉EC的数量。(6)将GFP标记的基因稳定地导入小鼠胚胎干（ES）细胞。建立Time-rap视频系统，分析ES细胞的分化和GFP标记基因的表达模式。(7)建立了紧密连接蛋白-5和EC特异性紧密连接蛋白的靶向破坏。(8)将人TERT基因和SV 40 T抗原基因导入人脐静脉内皮细胞（HUVECS）。表转染表现出细胞分裂能力的延长，并建议产生一种新的自分泌生长因子。

(1) Transient overexpression of transcription factor Ets1 promoted apoptosis of endothelial cells (Ecs). Ets1 increased expression of pro-apoptotic Bid, cytochrome p450, caspase-4, p27 and p21 more than 2 fold, while it decreased expression of anti-apoptotic DAD-1, AXL, Cox-2, IAP-2, and MDM-2 less than 0. 5 fold in Ecs. (2) The signal transduction pathway of VEGF appeared to be different between ECs of large vessels and small vessels. Especially, Ras played an important role in ECs of small vessels. (3) Transgenic mouse experiment revealed that VEGF-E, a new member of VEGF family, promoted angiogenesis without any evidences of vascular permeability. (4) Autophosphorylation sites of VEGFR-2 (KDR) were determined to be 1175Y and 1214Y. Carboxyl-terminal SH2 domain of PLC-γ bound to phosphorylated 1214Y, which was indispensable for the MAPK activation and augmented DNA synthesis. (5) MadCAM-1 was specifically expressed in venous ECs in the early embryonic stage. BMP-4 increased the number of MadCAM-1 positive venous ECs. (6) GFP-tagged genes were stably introduced into mouse embryonic stem (ES) cells. Time-rap video system was established to analyze the differentiation of ES cells and the expression pattern of GFP-tagged genes. (7) Target destruction of claudin-5, and EC-specific claudin, was established. (8) Human TERT gene and SV40 T antigen gene were introduced into human umbilical vein ECs (HUVECS). The table transfectants exhibited the prolongation of cell-division capability and were suggested to produce a novel autocrine growth factor.