Smooth muscle SIRT1 reprograms endothelial cells to suppress angiogenesis after ischemia
Smooth muscle SIRT1 reprograms endothelial cells to suppress angiogenesis after ischemia
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平滑肌 SIRT1 重新编程内皮细胞以抑制缺血后血管生成
DOI：
10.7150/thno.39320
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发表时间：
2020-01-01
期刊：
影响因子：
12.4
通讯作者：
Han, Mei
中科院分区：
文献类型：
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作者：
Dou, Yong-Qing;Kong, Peng;Han, Mei
目的：血管平滑肌细胞(VSMCs)在缺血后血管重塑过程中经历由收缩状态到合成状态的表型变化。SIRT1通过维持VSMC的分化表型来保护应激诱导的血管重塑。然而，SIRT1对血管内皮细胞(ECs)功能的影响尚不清楚。在此，我们探讨了SIRT1在缺血后内皮血管生成中的作用及其机制。方法：采用VSMC特异性人SIRT1转基因(SIRT1-TG)和基因敲除(KO)小鼠建立股动脉结扎模型。通过毛细血管总数、创面愈合和基质堵塞试验以及体外内皮细胞的管状形成、增殖和迁移试验来评估体内血管生成。用免疫沉淀法、α下拉和原位杂交等方法检测HIF1RNA与环状核糖核酸的相互作用。结果：SIRT1-TG小鼠血流恢复明显减弱，SIRT1-Tg小鼠经SIRT1抑制剂EX527治疗后血流恢复明显改善，SIRT1-KO小鼠血流恢复明显改善。SIRT1-TG小鼠缺血腓肠肌毛细血管密度明显低于SIRT1-KO和WT小鼠，VEGFA表达减少，导致小动脉数量减少。我们发现，与SIRT1-KO和WT VSMCs相比，SIRT1-TG VSMCs的表型转换在低氧条件下减弱，收缩蛋白水平高，合成标志物和NG2的表达减少。从机制上讲，SIRT1-TG VSMCs通过外切体cZFP609抑制缺氧诱导的内皮血管生成。将其导入内皮细胞，通过与α的相互作用，将α滞留在胞浆内，从而抑制血管内皮生长因子的表达和内皮血管生成功能。同时，动脉粥样硬化性或糖尿病周围动脉病变患者血浆中cZFP609的高表达与踝臂指数降低有关。敲除cZFP609可改善SIRT1-TG小鼠后肢缺血后的血流恢复。结论：SIRT1可能损害VSMC的可塑性。CZFP609介导VSMCs对内皮功能的重新编程，是评估缺血性疾病预后和临床结局的有价值的指标。
Objective: Vascular smooth muscle cells (VSMCs) undergo the phenotypic changes from contractile to synthetic state during vascular remodeling after ischemia. SIRT1 protects against stress-induced vascular remodeling via maintaining VSMC differentiated phenotype. However, the effect of smooth muscle SIRT1 on the functions of endothelial cells (ECs) has not been well clarified. Here, we explored the role of smooth muscle SIRT1 in endothelial angiogenesis after ischemia and the underlying mechanisms. Methods: We performed a femoral artery ligation model using VSMC specific human SIRT1 transgenic (SIRT1-Tg) and knockout (KO) mice. Angiogenesis was assessed in in vivo by quantification of the total number of capillaries, wound healing and matrigel plug assays, and in vitro ECs by tube formation, proliferation and migration assays. The interaction of HIF1α with circRNA was examined by using RNA immunoprecipitation, RNA pull-down and in situ hybridization assays. Results: The blood flow recovery was significantly attenuated in SIRT1-Tg mice, and markedly improved in SIRT1-Tg mice treated with SIRT1 inhibitor EX527 and in SIRT1-KO mice. The density of capillaries significantly decreased in the ischemic gastrocnemius of SIRT1-Tg mice compared with SIRT1-KO and WT mice, with reduced expression of VEGFA, which resulted in decreased number of arterioles. We identified that the phenotypic switching of SIRT1-Tg VSMCs was attenuated in response to hypoxia, with high levels of contractile proteins and reduced expression of the synthetic markers and NG2, compared with SIRT1-KO and WT VSMCs. Mechanistically, SIRT1-Tg VSMCs inhibited endothelial angiogenic activity induced by hypoxia via the exosome cZFP609. The cZFP609 was delivered into ECs, and detained HIF1α in the cytoplasm via its interaction with HIF1α, thereby inhibiting VEGFA expression and endothelial angiogenic functions. Meantime, the high cZFP609 expression was observed in the plasma of the patients with atherosclerotic or diabetic lower extremity peripheral artery disease, associated with reduced ankle-brachial index. Knockdown of cZFP609 improved blood flow recovery after hindlimb ischemia in SIRT1-Tg mice. Conclusions: Our findings demonstrate that SIRT1 may impair the plasticity of VSMCs. cZFP609 mediates VSMCs to reprogram endothelial functions, and serves as a valuable indicator to assess the prognosis and clinical outcomes of ischemic diseases.