Abstract：
OBJECTIVE: Proper arteriogenesis after tissue ischemia is necessary to rebuild stable blood circulation; nevertheless, this process is impaired in type-2 diabetes mellitus (T2DM). Raptor, is a scaffold protein and a component of mammalian target of rapamycin complex 1 (mTORC1). However, the role of the endothelial Raptor in arteriogenesis under the conditions of T2DM remains unknown. This study investigated the role of endothelial Raptor in ischemia-induced arteriogenesis during T2DM.
RESULTS: Although endothelial mTORC1 is hyperactive in T2DM, we observed a marked reduction in the expression of endothelial Raptor in two mouse models and in human vessels. Inducible endothelial-specific Raptor knockout severely exacerbated impaired hindlimb perfusion and arteriogenesis after hindlimb ischemic injury in 12-week high-fat diet fed mice. Additionally, we found that Raptor deficiency dampened vascular endothelial growth factor receptor 2 (VEGFR2) signaling in endothelial cells and inhibited VEGF-induced cell migration and tube formation in a PTP1B-dependent manner. Furthermore, mass spectrometry analysis indicated that Raptor interacts with neuropilin 1 (NRP1), the co-receptor of VEGFR2, and mediates VEGFR2 trafficking by facilitating the interaction between NRP1 and Synectin. Finally, we found that endothelial cell-specific overexpression of the Raptor mutant (loss of mTOR binding) reversed impaired hindlimb perfusion and arteriogenesis induced by endothelial Raptor knockout in high-fat diet fed mice.
CONCLUSIONS: Collectively, our study demonstrated the crucial role of endothelial Raptor in promoting ischemia-induced arteriogenesis in T2DM by mediating VEGFR2 signaling. Thus, endothelial Raptor is a novel therapeutic target for promoting arteriogenesis and ameliorating perfusion in T2DM.
RESULTS: Although endothelial mTORC1 is hyperactive in T2DM, we observed a marked reduction in the expression of endothelial Raptor in two mouse models and in human vessels. Inducible endothelial-specific Raptor knockout severely exacerbated impaired hindlimb perfusion and arteriogenesis after hindlimb ischemic injury in 12-week high-fat diet fed mice. Additionally, we found that Raptor deficiency dampened vascular endothelial growth factor receptor 2 (VEGFR2) signaling in endothelial cells and inhibited VEGF-induced cell migration and tube formation in a PTP1B-dependent manner. Furthermore, mass spectrometry analysis indicated that Raptor interacts with neuropilin 1 (NRP1), the co-receptor of VEGFR2, and mediates VEGFR2 trafficking by facilitating the interaction between NRP1 and Synectin. Finally, we found that endothelial cell-specific overexpression of the Raptor mutant (loss of mTOR binding) reversed impaired hindlimb perfusion and arteriogenesis induced by endothelial Raptor knockout in high-fat diet fed mice.
CONCLUSIONS: Collectively, our study demonstrated the crucial role of endothelial Raptor in promoting ischemia-induced arteriogenesis in T2DM by mediating VEGFR2 signaling. Thus, endothelial Raptor is a novel therapeutic target for promoting arteriogenesis and ameliorating perfusion in T2DM.
摘要：
目的：组织缺血后适当的动脉生成对于重建稳定的血液循环是必要的；然而，这一过程在2型糖尿病(T2DM)中受损.猛禽,是支架蛋白和哺乳动物雷帕霉素靶复合物1(mTORC1)的组分。然而,内皮细胞Raptor在T2DM患者动脉生成中的作用尚不清楚.本研究探讨了内皮Raptor在T2DM缺血诱导的动脉生成中的作用。
结果：虽然内皮细胞mTORC1在T2DM中呈过度活跃，我们在两种小鼠模型和人血管中观察到内皮Raptor的表达显著降低。可诱导的内皮特异性Raptor敲除严重加剧了12周高脂饮食喂养小鼠后肢缺血性损伤后后肢灌注和动脉生成受损。此外,我们发现Raptor缺乏抑制了内皮细胞中的血管内皮生长因子受体2(VEGFR2)信号传导,并以PTP1B依赖性方式抑制了VEGF诱导的细胞迁移和管形成.此外，质谱分析表明Raptor与神经纤毛蛋白1（NRP1）相互作用，VEGFR2的共受体，并通过促进NRP1和Synectin之间的相互作用来介导VEGFR2的运输。最后,我们发现,在高脂饮食喂养的小鼠中,内皮细胞特异性过表达Raptor突变体(mTOR结合缺失)逆转了内皮Raptor基因敲除诱导的后肢灌注和动脉生成受损.
结论：总的来说，我们的研究证明了内皮Raptor在通过介导VEGFR2信号促进T2DM缺血诱导的动脉生成中的关键作用.因此，内皮Raptor是促进T2DM动脉生成和改善灌注的新治疗靶点。
结果：虽然内皮细胞mTORC1在T2DM中呈过度活跃，我们在两种小鼠模型和人血管中观察到内皮Raptor的表达显著降低。可诱导的内皮特异性Raptor敲除严重加剧了12周高脂饮食喂养小鼠后肢缺血性损伤后后肢灌注和动脉生成受损。此外,我们发现Raptor缺乏抑制了内皮细胞中的血管内皮生长因子受体2(VEGFR2)信号传导,并以PTP1B依赖性方式抑制了VEGF诱导的细胞迁移和管形成.此外，质谱分析表明Raptor与神经纤毛蛋白1（NRP1）相互作用，VEGFR2的共受体，并通过促进NRP1和Synectin之间的相互作用来介导VEGFR2的运输。最后,我们发现,在高脂饮食喂养的小鼠中,内皮细胞特异性过表达Raptor突变体(mTOR结合缺失)逆转了内皮Raptor基因敲除诱导的后肢灌注和动脉生成受损.
结论：总的来说，我们的研究证明了内皮Raptor在通过介导VEGFR2信号促进T2DM缺血诱导的动脉生成中的关键作用.因此，内皮Raptor是促进T2DM动脉生成和改善灌注的新治疗靶点。
