1. Role of endothelial Raptor in abnormal arteriogenesis after lower limb ischaemia in type 2 diabetes.
- Author
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Liu T, Zhang J, Chang F, Sun M, He J, and Ai D
- Subjects
- Animals, Humans, Male, Regional Blood Flow, Muscle, Skeletal blood supply, Muscle, Skeletal metabolism, Cells, Cultured, Diabetic Angiopathies metabolism, Diabetic Angiopathies physiopathology, Diabetic Angiopathies genetics, Diabetic Angiopathies etiology, Diabetic Angiopathies pathology, Cell Movement, Human Umbilical Vein Endothelial Cells metabolism, Mice, Diabetes Mellitus, Type 2 metabolism, Diabetes Mellitus, Type 2 genetics, Regulatory-Associated Protein of mTOR metabolism, Regulatory-Associated Protein of mTOR genetics, Regulatory-Associated Protein of mTOR deficiency, Ischemia metabolism, Ischemia physiopathology, Ischemia genetics, Ischemia pathology, Hindlimb blood supply, Neovascularization, Physiologic, Mice, Knockout, Disease Models, Animal, Signal Transduction, Mice, Inbred C57BL, Vascular Endothelial Growth Factor Receptor-2 metabolism, Vascular Endothelial Growth Factor Receptor-2 genetics, Endothelial Cells metabolism, Endothelial Cells pathology
- Abstract
Aims: Proper arteriogenesis after tissue ischaemia 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 ischaemia-induced arteriogenesis during T2DM., Methods and 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 ischaemic injury in 12-week high-fat diet fed mice. Additionally, we found that Raptor deficiency dampened vascular endothelial growth factor receptor 2 (VEGFR2) signalling in endothelial cells (ECs) 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 EC-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., Conclusion: Collectively, our study demonstrated the crucial role of endothelial Raptor in promoting ischaemia-induced arteriogenesis in T2DM by mediating VEGFR2 signalling. Thus, endothelial Raptor is a novel therapeutic target for promoting arteriogenesis and ameliorating perfusion in T2DM., Competing Interests: Conflict of interest: none declared., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)
- Published
- 2024
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