VLDL-VLDLR通路激活中性粒细胞分泌exosomes促动脉粥样硬化的作用机制研究

Cholesterol carried by very low density lipoprotein (VLDL) is an important independent risk factor for atherosclerotic cardiovascular disease (CVD). Our previous cohort study found that increased levels of neutrophil VLDL receptor (VLDLR) in the population could significantly increase the risk of prevelance atherosclerosis caused by VLDL-C, but the mechanism was unclear. Latest reports and our preliminary experimental study has found that the concentration and component of neutrophils-drived exosomes play a key regulatory roal in atherosclerosis, thus we arise the research hypothesis that VLDL-VLDLR pathways activated neutrophils to secrete exosomes, which promotion atherosclerosis. Here, we will constructe the chimera model based on VLDLR-/- mice and wild type mice to explore the influence of neutrophils VLDLR pathways and neutrophils-drived exosomes in atherosclerosis. On the other hand, we will through lack of VLDLR or normal neutrophils model to explore the original generation VLDL - VLDLR pathways activated neutrophils secrete exosomes differences and molecular mechanism in atherosclerosis, to clarify neutrophils VLDL - VLDLR pathways to atherosclerosis mechanism and provides the basis for looking for new CVD prevention targets.

极低密度脂蛋白（VLDL）携带的胆固醇（VLDL-C）是动脉粥样硬化性心血管病（CVD）的重要独立危险因素。我们前期队列研究发现人群中性粒细胞VLDL受体（VLDLR）水平升高可显著增加VLDL-C致As危险，但具体机制不明。最新国内外报道及我们预实验研究发现中性粒细胞分泌exosomes浓度及组分在动脉粥样硬化中起关键调控作用，由此我们提出VLDL经VLDLR通路激活中性粒细胞分泌exosomes而促进As的研究假设。本研究拟基于VLDLR基因敲除小鼠的嵌合体模型探讨中性粒细胞VLDLR通路及中性粒细胞产生的exosomes对动脉粥样硬化的影响，通过VLDLR缺失或正常的原代中性粒细胞模型探讨VLDL-VLDLR通路激活中性粒细胞分泌exosomes的差异及在动脉粥样硬化中的分子机制，为阐明中性粒细胞VLDL-VLDLR通路致动脉粥样硬化作用机制和寻找新的CVD防治靶点提供依据

本项目是为寻找人群中性粒细胞VLDLR水平升高显著增加VLDL-C致动脉粥样硬化危险的具体机制。本研究以apoE缺陷小鼠为受体，构建VLDLR基因敲除小鼠为供体的嵌合体，在此基础上辅以高脂饮食建立动脉粥样硬化动物模型。在动物水平及分离的动物原代细胞水平探讨中性粒细胞VLDLR缺失对动脉粥样硬化形成的影响，以及VLDL经VLDLR途径对中性粒细胞分泌exosomes的影响及该exosomes在动脉粥样硬化中的作用及机制。结果发现：中性粒细胞VLDLR缺失不仅减少动脉粥样硬化斑块形成，还可改善动物整体的血脂水平。中性粒细胞的分泌的exosomes浓度及其miRNA表达与动脉粥样硬化形成密切相关，高浓度的exosomes释放及exosomes里携带的miR-223在诱导巨噬细胞迁移上发挥重要作用。汇总本项目研究结果提示VLDLR缺陷可能是抑制动脉粥样硬化进程的一个作用机制。在中性粒细胞与巨噬细胞通讯的过程中，VLDL-VLDLR诱导产生的exosomes促进了斑块形成，其中的miR-223是一个重要的通讯分子。可更进一步探讨miR-223参与动脉粥样硬化的机制，开发出miRNA作用靶点，为治疗动脉粥样硬化性心血管疾病提供更多的可能及相关小分子抑制剂药物研发的科学依据。