TRC40锚定UBL4A类泛素化ALDH1L1诱导内质网应激介导apelin促单核细胞-内皮细胞粘附

Applicant reported that apelin-13 (endogenous peptides of APJ receptor) could promote monocyte - vascular endothelial cell adhesion. Preliminary experiments found that apelin-13 increased the expression of 40kDa component of the transmembrane domain recognition complex (TRC40),ubiquitin-like 4A(UBL4A), aldehyde dehydrogenase 1 family member L1(ALDH1L1) and induced endoplasmic reticulum stress. According to that the scientific hypothesis “TRC40 anchors UBL4A sumoylation of ALDH1L1 inducing endoplasmic reticulum stress mediated monocyte and endothelial cell adhesion promoted by apelin -13” was proposed. We adopt RNA interference and other methods to explore whether apelin - 13 can promote vascular endothelial cell UBL4A sumoylation of ALDH1L1. We will analysis whether TRC40 recognition and anchors UBL4A sumoylation of ALDH1L1 may induce endoplasmic reticulum which participate in apelin-13 promotes vascular endothelial cells endoplasmic reticulum stress; and we will explore whether TRC40 anchores UBL4A sumoylation of ALDH1L1 can induce endoplasmic reticulum stress mediates monocyte-vascular endothelial cell adhesion promoted by apelin-13. From the new perspective that TRC40 anchores UBL4A sumoylation of ALDH1L1 induces endoplasmic reticulum stress ,so as to reveal the apelin/APJ promotes monocyte - vascular endothelial cell adhesion mechanisms, further clarify the mechanism of apelin/APJ would be involve in the ccurrence and development of atherosclerosis.

已报道APJ受体的配体apelin-13促单核细胞(M)-内皮细胞(EC)粘附，实验发现apelin-13促EC尾锚定蛋白识别复合物(TRC40)、类泛素化蛋白4A（UBL4A）、乙醛脱氢酶1L1（ALDH1L1）表达及诱导内质网应激，据此提出“TRC40锚定UBL4A类泛素化修饰的ALDH1L1诱导内质网应激介导apelin-13促单核细胞-血管内皮细胞粘附”假说。课题拟采用RNA干扰等技术明确apelin-13是否促EC的UBL4A类泛素化修饰ALDH1L1；分析TRC40是否识别并锚定UBL4A类泛素化的ALDH1L1到内质网膜参与apelin-13促EC内质网应激；探讨TRC40锚定UBL4A类泛素化的ALDH1L1诱导内质网应激是否介导apelin-13促M-EC粘附。课题从TRC40锚定UBL4A类泛素化的ALDH1L1诱导内质网应激揭示apelin-13促M-EC粘附新机理。

Apelin是一种新型的血管调节因子，本团队成员前期发现活性氧ROS可介导Apelin-13促单核细胞-血管内皮细胞粘附，但其具体机制尚未明确，因此，进一步深入研究Apelin/APJ系统对动脉粥样硬化发生发展的具体机制，将为抗动脉粥样硬化的早期预防和治疗提供了重要的资料。主要研究内容：1.证明UBL4A类泛素化修饰ALDH1L1。2.研究TRC40锚定UBL4A类泛素化修饰的ALDH1L1调控Apelin-13诱导血管内皮细胞内质网应激。3.探讨TRC40锚定UBL4A类泛素化修饰的ALDH1L1诱导内质网应激介导Apelin-13促单核细胞-血管内皮细胞粘附。本项目研究揭示以下重要成果：1. APJ拮抗剂F13A能抑制Apelin-13以浓度（0-1.0μM）和时间（0-24h）依赖性诱导的血管内皮细胞中转运蛋白TRC40、类泛素蛋白UBL4A﹑尾锚定蛋白ALDH1L1的表达。 2. RNA干扰UBL4A减弱Apelin-13诱导的ALDH1L1﹑内质网应激标志蛋白（BIP﹑CHOP）﹑细胞粘附分子（ICAM1﹑VCAM1）的表达。3. RNA干扰TRC40、RNA干扰ALDH1L1、内质网应激抑制剂（Salubrinal）均可减弱Apelin-13诱导的BIP﹑ICAM1﹑VCAM1的表达。4. 透射电子显微镜发现F13A能减弱Apelin-13诱导的内质网应激。5. F13A和Salubrinal均可减弱Apelin-13促单核细胞-人脐静脉内皮细胞粘附。6. F13A抑制Apelin-13促ApoE-/-小鼠主动脉血管内动脉粥样硬化斑块增大。本课题首次将Apelin/APJ系统、尾锚定蛋白ALDH1L1锚定至内质网诱导内质网应激、单核细胞-血管内皮细胞粘附联系起来，提出类泛素化蛋白UBL4A修饰尾锚定蛋白 ALDH1L1 这一新的方式，并引入了TRC40介导UBL4A类泛素化修饰的ALDH1L1锚定于内质网膜诱导内质网应激的新概念，这些是对Apelin-13促单核细胞-血管内皮细胞粘附新机制的研究重要的学术创新，对于深入揭示以APJ药物为靶点针对动脉粥样硬化的防治具有重要的科学意义。