IC53基因新功能-促动脉粥样硬化作用及其机制

Atherosclerosis is the primary cause of coronary artery disease (CAD) and stroke, the mechanism underlying atherosclerosis remains unclear. In our previous study, we found a gene named IC53, which was expressed in the macrophage of atherosclerosic plaque, results of immunoprecipitation and immunofluorescence showed IC53 physiological interacted with HSP90, which has been reported to promote atherosclerosis through inflammation. Overexpression of IC53 activated ERK-Elk-1 signal pathway, increased recruitment of phospho-ERK in HSP90-IC53 complex and promoted angiogenesis, which has been reported to promote atherosclerosis. Furthermore, the CC genotype of rs2737, located in the 3'UTR of IC53, created a miRNA379 binding site and protected against atherothrombotic stroke. These results led us to hypothesize that IC53 may promote atherosclerosis through angiogenesis and inflammation by interaction with HSP90 and the functional variant rs2737 may reduce atherosclerosic disease (stroke and CAD) risk by creating a miRNA379 target. To test our hypothesis, at first, we will investigate whether IC53 promote angiogenesis through HSP90-ERK signal pathway by tube formation assay on matrigel in vitro, whether IC53 promote angiogenesis in plaque through HSP90 by immunofluorescence in the ApoE knock out model, and whether IC53 promote inflammation through binding with HSP90 by detecting inflammationary cytokines such as IL-6, TNF-alpha, IL-1 alpha and beta, adhesion between monocyte and endothelial cells and activation of NF-κB and STAT3, quantification?of?monocyte?recruitment?into?plaques?by labeling monocyte?subsets?in?vivo?using?the?bead-labeling?approach. Next, the ApoE knock out mice will be applied to analyze the role of IC53 to promote atherosclerosis in vivo by infection of AdMax-empty, AdMax-IC53, AdMax-IC53-shRNA and AdMax-IC53 plus 17-DMAG, respectively. Finally, we will test the association between rs2737 and stroke or CAD in the four independent large samples with case-control study, and investigate the inhibition effect on IC53 translation, IC53-mediated angiogenesis or inflammation of miRNA379 at different rs2737 genotype by in situ hybridization, real time PCR, dual-luciferase reporter assay, tube formation, detecting inflammationary cytokines and activation of NF-κB and STAT3.We hope to verify the IC53 gene is a novel risk gene of atherosclerosis，dissect its underlying mechanism, and provide a novel target for prevention and therapy of atherosclerosic disease,through this project.

鉴定动脉粥样硬化（AS）相关新基因十分重要。我们前期发现IC53促血管新生并与HSP90相互作用，HSP90能促进血管新生、炎症反应及AS，IC53多态rs2737导致miR379可能抑制IC53并对脑血栓具有保护作用。据此，推测IC53能通过与HSP90相互作用促进血管新生及炎症从而促进AS。拟首先分析IC53是否通过HSP90-ERK通路促斑块血管新生（检测微管形成，血管新生相关因子表达），是否通过与HSP90作用促进炎症反应（检测炎症因子水平、NF-κB活化及单核细胞募集等），然后在ApoE敲除小鼠中分析IC53对AS斑块形成的作用，最后分析rs2737与冠心病、脑卒中遗传易感性的关系（病例对照研究）及miR379在rs2737不同基因型时对IC53翻译、IC53介导的血管新生及炎症的作用。从而证明IC53是新的促AS基因并明确其机制，为理解AS机制提供新视角,为AS防治提供新靶点。

IC53基因是一种新的动脉粥样硬化相关基因，其在该病的发生、发展过程中发挥重要作用。本项目采用氧化低密度脂蛋白（ox-LDL）处理内皮及单核细胞，探讨IC53在动脉粥样硬化过程中所发挥的调控作用。本研究主要取得了如下研究成果：第一，本研究首次证实，ox-LDL可诱导内皮细胞IC53蛋白表达显著升高，提示该蛋白很可能是动脉粥样硬化的关键调控蛋白。第二，IC53蛋白促进单核细胞的迁移、侵袭和粘附，并诱导内皮细胞凋亡，促进动脉粥样硬化进程。第三，IC53可与HSPB1、Annexin A2、Myo1E及SFN等多种动脉粥样硬化相关蛋白相互作用，并可调控MCP-1、TLR8及EFTUD2等多种动脉粥样硬化相关基因的表达。其中MCP-1很可能是IC53参与动脉粥样硬化调控的关键蛋白之一。本研究通过阐明IC53在单核细胞及内皮细胞两种参与动脉粥样硬化的关键细胞类型中的机制，对于动脉粥样硬化的治疗提供了新的靶点。