Glycation of extracellular matrix proteins has been demonstrated to contribute to the pathogenesis of vascular complications. However, no previous report has shown the role of glycated fibronectin (FN) in vascular endothelial growth factor (VEGF)‐induced angiogenesis. Thus, this study aimed to investigate the effects of glycated FN on VEGF signalling and to clarify the molecular mechanisms involved. FN was incubated with methylglyoxal (MGO) in vitro to synthesize glycated FN, and human umbilical vein endothelial cells (HUVECs) were seeded onto unmodified and MGO‐glycated FN. Then, VEGF‐induced angiogenesis and VEGF‐induced VEGF receptor‐2 (VEGFR‐2) signalling activation were measured. The results demonstrated that normal FN‐positive bands (260 kD) vanished and advanced glycation end products (AGEs) appeared in MGO‐glycated FN and glycated FN clearly changed to a higher molecular mass. The glycation of FN inhibited VEGF‐induced VEGF receptor‐2 (VEGFR‐2), Akt and ERK1/2 activation and VEGF‐induced cell migration, proliferation and tube formation. The glycation of FN also inhibited the recruitment of c‐Src to VEGFR‐2 by sequestering c‐Src through receptor for AGEs (RAGE) and the anti‐RAGE antibody restored VEGF‐induced VEGFR‐2, Akt and ERK1/2 phosphorylation, endothelial cell migration, proliferation and tube formation. Furthermore, the glycation of FN significantly inhibited VEGF‐induced neovascularization in the Matrigel plugs implanted into subcutaneous tissue of mice. Taken together, these data suggest that the glycation of FN may inhibit VEGF signalling and VEGF‐induced angiogenesis by uncoupling VEGFR‐2‐c‐Src interaction. This may provide a novel mechanism for the impaired angiogenesis in diabetic ischaemic diseases.

中文翻译：

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纤连蛋白的糖化通过解偶联 VEGF 受体-2-c-Src 串扰来抑制 VEGF 诱导的血管生成。

细胞外基质蛋白的糖化已被证明有助于血管并发症的发病机制。然而，之前没有报道显示糖化纤连蛋白 (FN) 在血管内皮生长因子 (VEGF) 诱导的血管生成中的作用。因此，本研究旨在研究糖化 FN 对 VEGF 信号传导的影响并阐明所涉及的分子机制。FN 在体外与甲基乙二醛 (MGO) 一起孵育以合成糖化 FN，并将人脐静脉内皮细胞 (HUVEC) 接种到未修饰和 MGO 糖化的 FN 上。然后，测量 VEGF 诱导的血管生成和 VEGF 诱导的 VEGF 受体-2（VEGFR-2）信号激活。结果表明，正常 FN 阳性条带 (260 kD) 消失，晚期糖基化终产物 (AGEs) 出现在 MGO 糖化 FN 中，糖化 FN 明显变为更高分子量。FN 的糖基化抑制了 VEGF 诱导的 VEGF 受体-2（VEGFR-2）、Akt 和 ERK1/2 的激活以及 VEGF 诱导的细胞迁移、增殖和管形成。FN 的糖基化还通过 AGE 受体 (RAGE) 隔离 c-Src 来抑制 c-Src 向 VEGFR-2 的募集，抗 RAGE 抗体恢复了 VEGF 诱导的 VEGFR-2、Akt 和 ERK1/2 磷酸化、内皮细胞细胞迁移、增殖和管形成。此外，FN 的糖基化显着抑制了植入小鼠皮下组织的 Matrigel 栓中 VEGF 诱导的新生血管形成。综合起来，这些数据表明 FN 的糖基化可能通过解偶联 VEGFR-2-c-Src 相互作用来抑制 VEGF 信号传导和 VEGF 诱导的血管生成。这可能为糖尿病缺血性疾病中受损的血管生成提供新的机制。