Intermedin Enlarges the Vascular Lumen by Inducing the Quiescent Endothelial Cell Proliferation
Intermedin Enlarges the Vascular Lumen by Inducing the Quiescent Endothelial Cell Proliferation
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Intermedin 通过诱导静止内皮细胞增殖来扩大血管腔
DOI：
10.1161/atvbaha.117.310317
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发表时间：
2018-02-01
影响因子：
8.7
通讯作者：
Zhang, Wei
中科院分区：
文献类型：
--
作者：
Wang, Li-jun;Xiao, Fei;Zhang, Wei
目的中介素在血管重构中起重要作用，并能显著改善血液灌注，但其确切机制尚不清楚。方法和结果为了研究intermedin的作用，我们使用CRISPR/Cas9（clustered regularly interspaced short palindromic repeat/clustered regularly interspaced short palindromic repeat-associated 9）系统产生了IMD-KO（Adm 2（-/-））小鼠。Intermedin在体外（纤维蛋白珠测定）和体内（鼠视网膜）显著促进血管腔扩大，这有助于改善生理（视网膜）和病理（肿瘤）血管生成模型中的血液灌注。我们设计实验来计算内皮细胞（EC）的大小，发现管腔扩大是因为EC增殖，而不是因为细胞形状的变化。构建血管壁的EC被认为是静止细胞，因为它们处于接触抑制状态，并且对VEGF（血管内皮生长因子）的反应性降低。通过免疫沉淀、Western blot和荧光显微镜观察，我们发现Intermedin诱导ECs形成一个包含CRLR（calcitonin receptor-like receptor）/-arr 1（-arrestin 1）/Src的信号复合物，并以网格蛋白依赖的方式促进其内化到细胞质中，从而激活下游的ERK 1/2（extracellular signal-regulated kinase 1/2）。重要的是，这种作用并没有被EC的细胞-细胞接触所消除。通过这一机制，intermedin可以重新激活静止的EC增殖，导致连续的管腔扩张和更有效的血液perfusion.Conclusions我们的研究结果提出了一种新的机制，可以解释如何静止的EC克服接触抑制和恢复能力的连续血管管腔扩张的增殖。
Objective Intermedin plays an important role in vascular remodeling and significantly improves blood perfusion, but the precise mechanism remains unclear. Herein, we aimed to define whether vascular lumen enlargement is responsible for the intermedin-increased blood perfusion and explore the underlying cellular and molecular mechanisms.Approach and Results To study the role of intermedin, we generated the IMD-KO (Adm2(-/-)) mice using CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/clustered regularly interspaced short palindromic repeat-associated 9) system. Intermedin significantly promoted vascular lumen enlargement in vitro (fibrin beads assay) and in vivo (murine retinas), which contributed to the improved blood perfusion in both physiological (retinal) and pathological (tumor) angiogenic models. We designed experiments to calculate the endothelial cell (EC) size and found that the lumen enlargement is because of EC proliferation but not because of a change in cell shape. ECs that construct vessel walls are considered quiescent cells because they are in a state of contact inhibition and show reduced responsiveness to VEGF (vascular endothelial growth factor). Using immunoprecipitation, Western blot assay, and fluorescent microscopy, we found that intermedin induced the formation of a signaling complex containing CRLR (calcitonin receptor-like receptor)/-arr1 (-arrestin1)/Src in ECs and promoted it internalizing into cytoplasm in a clathrin-dependent manner to activate downstream ERK1/2 (extracellular signal-regulated kinase 1/2). Importantly, this effect was not abrogated by cell-cell contacts of ECs. Through this mechanism, intermedin could reactivate the quiescent ECs to proliferate, resulting in continuous lumen expanding and a more effective blood perfusion.Conclusions Our findings suggest a novel mechanism that may explain how quiescent ECs overcome the contact inhibition and regain the ability to proliferate for continuous vascular lumen enlargement.