从JAK2/STAT3通路研究A-FABP介导的巨噬细胞“自噬-凋亡对话”促动脉粥样硬化机制

Macrophage apoptosis is a major cause of plaque rupture. The balance between autophagy and apoptosis determines cell fate, and influences atherosclerosis(AS) progression. A-FABP deficiency can mediate protection from lipid induced-apoptosis in macrophages and the course of AS, although the underlying mechanisms remain unknown. Our previous studies have suggested that one potential way A-FABP can modulate stress responses to toxic lipids may be through alteration in mitochondria function and autophagy. Here, a comprehensive evaluation is presented of status of autophagy, mitochondrial function and apoptosis by utilizing multiple techniques. We demonstrate in vivo the relationship between AS and A-FABP, and confirm the critical role of A-FABP in mediating macrophage mitochondrial damage and autophagy/apoptosis imbalance in the setting of dyslipidemia in AS utilizing ApoE-/- mouse model. Then in vitro A-FABP is silenced/ overexpressed in RAW264.7 macrophage cells to futher confirm its role as an obligatory intermediate for autophagy/apoptosis imbalance. Various blocking strategies are developed to inhibit JAK2 and autophagy to uncover the signaling of lipid-induced autophagy/apoptosis imbalance in macrophages, and examine the impact of autophagy on A-FABP-mediated mitochondrial injury and apoptosis. In conclusion, the study will uncover a previous unknown function for A-FABP in lipid-induced autophagy/apoptosis imbalance in macrophages, while addressing the essential role of mitochondrial function in A-FABP-mediated lipotoxic signaling.

巨噬细胞凋亡是斑块破裂的重要因素。自噬/凋亡平衡决定了细胞命运，并影响动脉粥样硬化AS进程。A-FABP介导毒性脂质所致巨噬细胞凋亡而促AS发展，但其机制尚未阐明。本项目在我们先前证明 A-FABP增强脂毒性的作用可能与线粒体损伤及自噬有关的基础上，拟从整体、细胞以及亚细胞水平，综合运用多种技术对自噬、线粒体损伤、线粒体功能及凋亡展开全方位评价。利用ApoE-/-小鼠模型，体内论证A-FABP与AS发展的关系及对粥样斑块中巨噬细胞线粒体损伤及自噬/凋亡变化的作用。然后在巨噬细胞中使其沉默和过表达进行体外验证，并采用多种阻断策略依次抑制JAK2和自噬，明确作用的信号传导途径，及自噬对A-FABP介导的线粒体损伤及凋亡的影响。本课题首次以自噬-凋亡的交叉对话与A-FABP关系为切入点，从线粒体角度揭示了A-FABP对巨噬细胞凋亡/自噬平衡的调控及其信号传导途径，为AS发病机制提供新的理论依据。

糖脂代谢紊乱是围术期的常见问题，其对遭受手术麻醉应激患者的影响和作用机制远未阐明。在本项目资助下，申请者以巨噬细胞免疫调控作用为切入点，深入开展了糖脂代谢紊乱对围术期器官功能损害的作用及机制研究。我们首先探讨了高脂环境对围术期斑块不稳定性的影响及机制，发现毒性脂质会导致巨噬细胞线粒体功能障碍及凋亡，揭示了A-FABP促斑块不稳定的可能机制。本课题基本按原计划施行，未做重大原则性修改。在课题顺利进展和逐步完成的基础上，我们也进行了新的实验设计和研究。申请者发现持续性高糖会激活巨噬细胞 TLR4/JNK 信号，上调炎症因子水平，而波动性高糖较持续性高糖可进一步加重巨噬细胞的炎症反应；进一步发现A-FABP是调控这一途径的关键分子。以上提示防治血糖波动是糖尿病患者围术期炎症反应调控的重要策略，而A-FABP有望作为调控围术期糖脂代谢紊乱诱发炎症反应的潜在靶点。