重组人血管内皮生长因子D诱导鸡胚尿囊膜血管增生

为了表达和纯化具有生物学活性的人血管内皮生长因子（vascular endothelial growth factor,VEGF）-D,探讨VEGF-D对血管增生作用,从人胎肺组织中提取总RNA,设计特异性引物并应用RT-PCR法扩增VEGF-D成熟肽片段;经测序证明目的片段序列正确后,构建重组表达质粒pGEX-5X-1/VEGF-D并在大肠杆菌BL21（DE3）中进行GST-VEGF-D融合蛋白的表达。结果表明,融合蛋白的分子量约为38kD,表达量占菌体总蛋白的15%以上,抗GST和抗VEGF-D的抗体均能识别融合蛋白;纯化的GST-VEGF-D融合蛋白与VEGFR-3/Fc具有结合活性,并能刺激红白血病细胞系HEL细胞生长;在鸡胚尿囊膜实验中GST-VEGF-D具有促进鸡胚尿囊膜血管生成的作用。结论：成功表达了具有生物学活性的重组人VEGF-D融合蛋白,为进一步研究VEGF-D的作用机理提供了实验模型。

Recombinant Human VEGF-D Induces the Angiogenesis of the Chick Embryo Chorioallantoic Membrane

Vascular endothelial growth factor-D (VEGF-D) and vascular endothelial growth factor receptor-2,-3 (VEGFR-2,-3) with their corresponding signaling pathway play significant roles in the development of the embryonic vascular system and pathological lymphangiogenesis. The study was aimed to express and purify the GST-VEGF-D fusion protein, and to explore the angiogenesis effect of VEGF-D. The total RNA was extracted from human fetal lung tissue, and the mature form of VEGF-D was expanded by polymerase chain reaction (PCR), then the plasmid pGEX-5X-1/VEGF-D was reconstructed and the GST-VEGF-D fusion protein expressed in transformed E.coli BL21-DE3.The results showed that the molecular mass of this fusion protein was 38 kD and compassed more than 15% of the total bacteria proteins.The fusion protein was recognized by anti-GST and anti-VEGF-D antibodies.The soluble GST-VEGF-D fusion protein could interact with VEGFR-3/Fc and was able to stimulate the proliferation of human erythroleukemia cell line(HEL) cells. The data of chick embryo chorioallantoic membrane (CAM) experiments indicated that GST-VEGF-D could induce the CAM angiogenesis. It is concluded that the GST-VEGF-D fusion protein with biological activity was successfully expressed, and which may provide an experimental model for the investigation of the VEGF-D-induced angiogenesis and lymphangiogenesis.