高糖激活VEGF受体和TNF受体共调控内皮祖细胞的增殖与凋亡信号通路的作用机制

Endothelial progenitor cells (EPC) dysfunction and apoptosis are involved in many vascular diseases of the common pathological basis．Vascular endothelial growth factor receptor(VEGFR)and tumor necrosis factor receptor (TNFR) mediated intracellular signal transduction pathway plays an pivot role in regulating the proliferation and apoptosis of EPC. We have found that high glucose can induce increase of TNFR1 expression and downregulation of VEGF1 expression through accumulate of oxidative stress. We hypothesis that High glucose induced the activation of VEGFR and TNFR-mediated cellular signaling pathway that co-regulate vascular endothelial cells proliferation and apoptosis. We further research project includes the following three parts:(1)to determine how the high glucose effect. EPC's dysfunction.(2) to determine whether high glucose plays a key role in the development of vascular lesions and the imbalance of VEGFR2 and TNFR1 mediated signaling pathway associated with the endothelial dysfunction．(3) a preliminary study on the therapeutic effects of oligomer proanthocyanidins in diabetic rats with vascular diseases in vivo to determine whether high glucose plays a key role in the development of vascular lesions. The subjects of this research is to discuss the mechanism contributing to diabetic trunk and capillaries complication and can help clinic.

内皮祖细胞功能障碍和凋亡是许多血管受累性疾病的共同发病基础, 血管内皮生长因子受体(VEGFR)和肿瘤坏死因子受体(TNFR)介导的细胞内信号转导通路对内皮祖细胞的增殖、功能障碍和凋亡有着重要的调控作用.我们前期研究发现：高糖抑制了内皮祖细胞的增殖并诱导其凋亡，高糖能引起内皮祖细胞TNFR表达增高，VEGFR的表达降低。且与氧化应激反应密切相关。因此我们假设高糖可能通过氧化应激反应激活该两条信号通路调控科内皮祖细胞的增殖与凋亡。我们拟在前期研究的基础上进一步研究：（1）高糖引起氧化应激对于内皮祖细胞的影响（2）高糖通过激活VEGF 及TNF通路调控内皮祖细胞增殖与凋亡（3）制作糖尿病大鼠后肢缺血模型，并以抗氧化剂干预，体内试验验证。本项目了解糖尿病缺血后侧枝循环建立困难的血管并发症的机理而指导临床治疗。

本研究通过对高糖环境下体外培养的大鼠内皮祖细胞进行干预，首次发现：1. 高糖能够诱导EPC增加TNFR-1 mRNA表达，抗氧化剂TEMPOL能抑制这一效应,说明高糖诱导的EPC氧化应激反应可能通过激活TNF受体调控EPC凋亡。2. 高糖明显抑制大鼠EPCs VEGFR的表达，但在抗氧化剂的治疗干预下，明显提高了高糖干预组EPCs VEGFR的表达，并在一定程度上挽救了高糖干预组EPCs VEGFR表达的严重缺陷。3. 原花青素可能通过缓解高糖环境对EPCs的氧化损伤作用，上调内皮祖细胞VEGFR-2及其下游通路蛋白表达进而促进了细胞增殖。上述结论证实了我们对于高糖可能通过TNF及VEGF通路共调控EPC的凋亡与增殖，可能为治疗糖尿病血管病变提供新的靶点。

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