PCSK9-MIF介导单核/巨噬细胞促进动脉粥样硬化形成的分子机制及靶向干预研究

高胆固醇血症及炎症反应是诱发动脉粥样硬化（Atherosclerosis，AS）形成的关键危险因素。我们研究发现：PCSK9在肝脏的靶向表达导致显著的血脂代谢紊乱和AS表型，同时诱导肝源性巨噬细胞移动抑制因子（MIF）的合成及分泌，但机制不清楚，提出“PCSK9-MIF-CD36/SR-A/TLR4-NF-κB”级联信号通路轴向调控血管壁脂质蓄积和慢性炎症反应的科学假说。本项目拟采用全身及肝脏特异性MIF基因敲除的小鼠及细胞，构建过表达及靶向编辑肝脏PCSK9的新型重组AAV8.2载体，通过体内外转染实验，在细胞、组织及动物整体水平上，系统研究PCSK9通过MIF调控单核/巨噬细胞脂质吞噬与炎症反应的分子机制；明确基因编辑技术靶向沉默肝脏PCSK9、纠正血脂异常、抑制肝源性MIF生成实现防治AS的效果，确定PCSK9结合MIF作为AS治疗靶标的叠加效用，为AS的防控提供新的思路和手段。

Hypercholesterolemia and inflammatory response are the key risk factors of atherosclerosis (AS). Our pilot study revealed that genetically overexpression of proprotein convertase subtilisin/kexin type 9 (PCSK9) in the liver resulted in a significant lipid disorder and AS phenotype. Meanwhile this genetic intervention induced an increased synthesis and secretion of liver-derived macrophage migration inhibitory factor (MIF), a key pro-atherosclerotical and pro-inflammatory factor. However, the mechanism of PCSK9 promoting AS via MIF is unknown. We therefore hypothesize that the signaling cascade of “PCSK9-MIF-CD36/SR-A/TLR4-NF-κB” is the major mechanism regulating lipid deposition in the vascular wall and chronic inflammatory response during the development of AS. This proposed project aims to (1) systemically investigate the molecular mechanism of PCSK9–MIF regulating monocyte/macrophage lipid uptake and pro-inflammatory response by 1) use global and liver-specific MIF knockout mice and monocyte/macrophages and 2) establishing a novel and recombinant AAV8.2 vector to induce overexpression of PCSK9 in the liver and cells or silencing liver PCSK9 in mice; (3) elucidate the effects of lipid control, inhibition of liver-derived MIF and ultimately reducing AS by gene-editing technology to silence liver PCSK9 and (4) explore the therapeutic efficacy of combination of PCSK9 silencing and MIF inhibition and provide a new insight and strategy for AS treatment.