“VEGF抵抗”是糖尿病血管新生障碍的重要原因，其机制远未阐明。AGEs及其受体RAGE参与了糖尿病血管新生障碍的发生，但AGEs对“VEGF抵抗”的影响尚未见报道。申请人预实验发现：AGEs-BSA显著降低了VEGF介导的VEGFR-2的磷酸化和内皮细胞迁移，这提示AGEs可能抑制了VEGF信号的激活；我们进一步证实AGEs-BSA介导RAGE-mDia-1-Src形成复合物，而VEGFR-2对Src的招募是VEGF信号激活的关键。由此我们假设：AGEs通过RAGE-mDia-1-Src通路剥夺VEGF信号激活时VEGFR-2对Src的招募，从而抑制VEGF信号及其介导的血管新生，导致“VEGF抵抗”。本项目拟利用免疫共沉淀、RNA干扰、下肢缺血模型等手段探讨AGEs对VEGF信号及其介导血管新生的影响，旨在阐明“VEGF抵抗”产生的原因和机理，为糖尿病血管新生障碍的防治提供理论依据。

Vascular endothelial growth factor (VEGF) resistance has been demonstrated as a molecular basis for the impaired angiogenesis in diabetes mellitus. The molecular mechanism underlying VEGF resistance is not fully understood. Advanced glycation end products (AGEs) and receptor for AGEs (RAGE) contribute to the pathogenesis of impaired angiogenesis in diabetes mellitus. However, no previous studies have implicated the role of AGEs in VEGF resistance. Our preliminary results demonstrated that AGEs-BSA significantly decreased VEGF-induced phosphorylation of VEGF receptor-2 (VEGFR-2) and endothelial cell migration, which indicates that AGEs may inhibit VEGF-induced angiogenesis. Furthermore, we found that AGEs-BSA induced RAGE-mDia-1-Src complex formation in endothelial cells. And previous reports have shown that the recruitment of Src to VEGFR-2 is required for VEGF/VEGFR-2 signaling activation. Taken together, we hypothesize that AGEs prevents VEGF signaling and VEGF-induced angiogenesis by sequestering Src through RAGE-mDia-1-Src signaling pathway. In this study, immunoprecipitation, RNA interference and hindlimb ischemia model will be used to investigate the effects of AGEs on VEGF signaling and VEGF-induced angiogenesis. We anticipate that the proposed studies will explain the molecular mechanism of VEGF resistance and provide a novel therapeutic target for treatment of impaired angiogenesis in people with diabetes mellitus.