CTRP9通过AMPK/ATF-1/LXRα途径抑制动脉粥样硬化形成的分子机制

Accumulation of foam cells derived from macrophages is an important pathological feature of atherosclerotic lesions at an early stage. C1q/ tumor necrosis factor related protein 9 (CTRP9) plays an important role in the occurrence and development of atherosclerosis. Our previous studies have found that overexpression of CTRP9 significantly inhibits atherosclerosis in ApoE knockout mice induced by a high fat diet, but its molecular mechanism remains unknown. In this study, we will use CTRP9 transgenic and knockout mice: (1) To elucidate the mechanism of CTRP9 inhibiting atherosclerosis; (2) To verify whether that CTRP9 promotes cholesterol efflux in macrophages by activating AMPK phosphorylated nuclear transcription factor ATF-1, and up-regulating the expression of nuclear receptor LXRα, thereby increasing the expression of downstream target genes in macrophages. (3) The recovery experiment was to validate the effect of CTRP9 on atherosclerosis in vivo by adenovirus overexpression technology. The purpose of this study is to elucidate the molecular mechanism of CTRP9 regulating atherosclerosis by activating AMPK/ATF-1/LXRα signal axis, further reveal the relationship between CTRP9 and atherosclerosis, and provide a new target and theoretical basis for the prevention and treatment of atherosclerosis.

巨噬细胞泡沫化是动脉粥样硬化病变早期阶段的重要病理特征，C1q/肿瘤坏死因子相关蛋白9（CTRP9）在动脉粥样硬化发生、发展中具有重要作用。我们的前期研究发现过表达CTRP9显著抑制高脂饮食诱导的ApoE基因敲除小鼠动脉粥样硬化形成，其分子机制仍然未知。本课题拟采用CTRP9转基因及基因敲除小鼠模型：（1）利用转基因小鼠模型研究CTRP9抑制动脉硬化的作用机制；（2）利用巨噬细胞揭示CTRP9通过AMPK磷酸化核转录因子ATF-1，上调核受体LXRα表达，进而增加下游目标基因表达促进巨噬细胞中胆固醇外流；（3）利用腺病毒过表达技术进行在体恢复实验，验证CTRP9缺失后再恢复对动脉硬化的影响。本课题旨在阐明CTRP9通过活化AMPK/ATF-1/LXRα信号轴调控动脉硬化形成的分子机制，进一步揭示CTRP9与动脉硬化的关系，为动脉硬化的防治提供新的靶点和理论依据。

动脉粥样硬化是心血管疾病的主要病理基础，巨噬细胞的“泡沫化”是动脉粥样硬化病变发生的重要阶段。研究其发病机制，对心血管疾病的防治具有重大意义。C1q/肿瘤坏死因子相关蛋白9（CTRP9）在动脉粥样硬化发生、发展中具有重要作用。本研究利用病毒过表达以及干扰技术，通过尾静脉注射以及高脂高胆固醇饮食饲喂，探索CTRP9过表达或者敲低对动脉粥样硬化斑块形成的影响。结果表明，过表达CTRP9显著减少ApoE敲除小鼠动脉粥样硬化斑块的形成，而利用腺相关病毒敲低CTRP9的表达，ApoE敲除小鼠主动脉动脉粥样硬化斑块的形成显著减少。为了探索巨噬细胞中缺失CTRP9对动脉粥样硬化斑块形成的影响，利用高能x射线处理LDLr敲除小鼠，并将CTRP9敲除鼠骨髓细胞进行移植，结果显示巨噬细胞中缺失CTRP9的LDLr敲除小鼠动脉粥样硬化斑块形成显著增多。为了进一步揭示CTRP9调控动脉粥样硬化的分子机制，利用转录组测序技术挖掘差异表达基因，KEGG富集信号通路筛选发现线粒体氧化磷酸化相关基因表达水平被显著激活，过表达或干扰CTRP9均显著改变血浆氧化应激相关因子表达水平。这些结果进一步说明CTRP9在动脉粥样硬化形成过程中扮演重要角色，进一步揭示CTRP9与动脉粥样硬化的关系，为动脉粥样硬化的防治提供新的靶点和理论依据。