细胞骨架结合蛋白4.1R在巨噬细胞源性泡沫细胞形成和驻留中的作用及分子机制

Foam cell formation and retention in vascular subendothelium was the hallmark event of early stage in atherosclerosis. Actin cytoskeleton was closely related to the atherosclerosis disease progress and played the important role on formation and retention of macrophage-derived foam cells(MDFC). Protein 4.1R was the classical cytoskeleton binding protein which was involved in regulation of the distribution and function of membrane protein and intervened in membrane receptors signaling pathway. In our previous work, we found that the 4.1R mRNA expression in MDFC was significant upregulated with oxLDL stimulation. Moreover, 4.1R gene deletion would decrease the cholesterol accumulation in MDFC, attenuate the phagocytosis of MDFC and reduce the quantity of CD36 receptor on MDFC membrane. These results suggested that protein 4.1R was the important molecular involved in formation and retention of MDFC. In this work, we will study the role of protein 4.1R in the whole process of formation and retention of MDFC, investigate the regulatory function of protein 4.1R on cytoskeleton polymerization and rearragement, and clarify the molecular mechanism of protein 4.1R involved in formation and retention of MDFC. It would deepen our understanding of the function of cytoskeleton in formation and retention of MDFC. Morevoer, it propose the new target for reversing the formation and retention of MDFC as well as prevention and therapy of atherosclerosis.

泡沫细胞形成并在血管内皮下驻留是动脉粥样硬化（AS）形成的早期事件和标志。肌动蛋白细胞骨架与AS的发生关系密切，在巨噬源性泡沫细胞（MDFC）的形成和驻留中发挥重要作用。蛋白4.1R是重要的细胞骨架结合蛋白，依赖肌动蛋白细胞骨架改变膜蛋白的分布和功能，调控膜受体信号转导。我们前期研究发现，oxLDL刺激显著上调MDFC中4.1R的表达。4.1R基因缺失减少MDFC中胆固醇的累积，减弱胞吞作用，减少CD36受体膜分布。以上结果提示，蛋白4.1R是参与MDFC形成和驻留的重要调控分子。本项目将系统全面地研究4.1R在MDFC形成及驻留中的作用，及其对MDFC肌动蛋白骨架的聚合和重排的调控作用，阐明4.1R影响MDFC形成及驻留的分子机制。通过项目的实施将为理解细胞骨架参与调控MDFC形成和驻留累积实验依据，为逆转泡沫细胞形成和驻留，以及预防和治疗动脉粥样硬化提供潜在的靶点。

肌动蛋白细胞骨架在巨噬源性泡沫细胞（MDFC）的形成和驻留中发挥重要作用，与动脉粥样硬化（AS）的发生关系密切。蛋白4.1R作为重要的细胞骨架结合蛋白，依赖肌动蛋白细胞骨架改变膜蛋白的分布和功能，调控膜受体信号转导，提示其可能在MDFC的形成和驻留中发挥重要的作用，是研究AS病理机制值得关注的关键分子。项目利用4.1R+/+MDFC和4.1R-/-MDFC细胞模型，在分子，细胞及组学水平探究了细胞骨架结合蛋白4.1R在MDFC形成和驻留中的作用及分子机制。结果显示，oxLDL刺激能够显著增加MDFC蛋白4.1R的mRNA及蛋白表达水平；转录组分析提示蛋白4.1R缺失显著影响MDFC的NF-κB炎性信号通路；蛋白4.1R缺失减少MDFC脂质累积和胞内胆固醇含量；蛋白4.1R缺失显著降低MDFC炎性细胞因子MCP-1, IL-6和IL-1β的表达及活性氧ROS的分泌；蛋白4.1R缺失显著提高MDFC的迁移能力；蛋白4.1R缺失导致MDFC细胞表面CD36受体定位减少、肌动蛋白聚合程度降低以及oxLDL的摄取能力减弱；蛋白4.1R缺失显著降低CD36-Lyn-MEKK2-MAPK/FAK信号通路活化程度。综上所述，蛋白4.1R缺失可能通过影响MDFC的细胞骨架的稳定性和清道夫受体CD36的膜表达定位，减少oxLDL的摄取，进一步通过抑制CD36-Lyn-MEKK2-MAPK/FAK信号通路活化，最终影响MDFC的形成。本研究证实了蛋白4.1R在MDFC的形成和驻留中发挥重要作用并阐明了其作用机制。所得出的结论为AS早期病程中细胞骨架稳态影响MDFC形成和驻留的研究提供新的的实验依据，同时也为蛋白4.1R作为AS的早期诊断和治疗的潜在靶点提供了理论和实验依据。

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