Role of Afadin in Vascular Endothelial Growth Factor- and Sphingosine 1-Phosphate-Induced Angiogenesis
Role of Afadin in Vascular Endothelial Growth Factor- and Sphingosine 1-Phosphate-Induced Angiogenesis
复制标题
DOI：
10.1161/circresaha.110.216747
复制
发表时间：
2010-06-11
影响因子：
20.1
通讯作者：
Takai, Yoshimi
中科院分区：
文献类型：
--
作者：
Tawa, Hideto;Rikitake, Yoshiyuki;Takai, Yoshimi
理论基础：血管生成有助于生理和病理条件，包括动脉粥样硬化。Rap1小G蛋白调节血管完整性和血管生成。然而，对RAP1参与血管生成的效应因子知之甚少。Fafadin是一种连接免疫球蛋白样黏附分子Nectins到肌动蛋白细胞骨架并结合激活的Rap1的黏附连接蛋白，目前尚不清楚它是否在血管生成中发挥作用。目的：研究内皮Fadin在血管生成中的作用，并试图阐明其分子机制。方法和结果：血管内皮生长因子(VEGF)和1-磷酸鞘氨醇(S1P)处理人脐静脉内皮细胞(HUVECs)后，诱导RAP1激活。激活的RAP1调节Fafadin的细胞内定位。RAP1或afadin被小干扰RNA敲除后，可抑制血管内皮生长因子和S1P诱导的毛细血管样网络的形成、迁移和增殖，并增加血清剥夺诱导的HUVECs的凋亡。RAP1或afadin的敲除减少了粘附物和紧密连接蛋白在细胞-细胞接触部位的积累。Rap1调控着afadin与磷脂酰肌醇3-激酶(PI3K)之间的相互作用，使afadin-PI3K复合体聚集到前沿，并激活Akt，提示Rap1和afadin参与了PI3K-Akt信号通路。Afadin与Rap1的结合以正反馈的方式调节Rap1的活性。在体内，利用Cre-loxP系统有条件地缺失小鼠血管内皮细胞中的afadin，可抑制VEGF和S1P诱导的血管生成。结论：Rap1和afadin调控VEGF和S1P诱导的血管生成是一种新的分子机制。(中国保监会决议2010；106：1731-1742。)
Rationale: Angiogenesis contributes to physiological and pathological conditions, including atherosclerosis. The Rap1 small G protein regulates vascular integrity and angiogenesis. However, little is known about the effectors of Rap1 involved in angiogenesis. It is not known whether afadin, an adherens junction protein that connects immunoglobulin-like adhesion molecule nectins to the actin cytoskeleton and binds activated Rap1, plays a role in angiogenesis.Objective: We investigated the role of endothelial afadin in angiogenesis and attempted to clarify the underlying molecular mechanism.Methods and Results: Treatment of human umbilical vein endothelial cells (HUVECs) with vascular endothelial growth factor (VEGF) and sphingosine 1-phosphate (S1P) induced the activation of Rap1. Activated Rap1 regulated intracellular localization of afadin. Knockdown of Rap1 or afadin by small interfering RNA inhibited the VEGF-and S1P-induced capillary-like network formation, migration, and proliferation, and increased the serum deprivation-induced apoptosis of HUVECs. Knockdown of Rap1 or afadin decreased the accumulation of adherens and tight junction proteins to the cell-cell contact sites. Rap1 regulated the interaction between afadin and phosphatidylinositol 3-kinase (PI3K), recruitment of the afadin-PI3K complex to the leading edge, and the activation of Akt, indicating the involvement of Rap1 and afadin in the PI3K-Akt signaling pathway. Binding of afadin to Rap1 regulated the activity of Rap1 in a positive-feedback manner. In vivo, conditional deletion of afadin in mouse vascular endothelium using a Cre-loxP system impaired the VEGF-and S1P-induced angiogenesis.Conclusions: These results demonstrate a novel molecular mechanism by which Rap1 and afadin regulate the VEGF-and S1P-induced angiogenesis. (Circ Res. 2010; 106: 1731-1742.)