糖酵解限速酶丙酮酸激酶M2(PKM2)介导T淋巴细胞代谢重塑在高同型半胱氨酸血症促进动脉粥样硬化提前发病中的作用和调控机制

Hyperhomocysteinemia (HHcy) accelerates atherosclerosis in apoE-/- mice by enhancing T cell inflammatory activation. It has been known that metabolic reprogramming is critical for T cell activation and function. Our previous study has shown that homocysteine (Hcy) promotes splenic T cell activation by increasing ER-mitochondria coupling and mitochondrial functions, but the precise mechanism of how metabolic reprogramming contributes to Hcy-induced T cell activation is still unclear. PKM2 is the final rate-limiting enzyme in glycolysis. In the present study, we will identify an important role of PKM2-dependent metabolic reprogramming as determined by liquid chromatography-tandem mass spectrometry in regulating HHcy-induced early overactivation of T cells. In the preliminary experiments, we have found that HHcy-accelerated atheroclerosis in ApoE-/- mice was successfully ameliorated by PKM2 inhibitor shikonin in vivo, which was at least in part due to reduced CD4+ T cell activation. On the basis of this, we will further confirm the role of PKM2-induced glucose-lipid metabolic axis of T cells in HHcy-accelerated atheroclerosis by use of lck-Cre PKM2fl/fl mice in which PKM2 was specific knockout in T cells. These results shed light on the pathological mechanisms of HHcy-relative cardiovascular diseases.

高同型半胱氨酸血症(HHcy)是动脉粥样硬化的独立危险因素。前期研究表明HHcy增强线粒体功能而过度激活T细胞，进而加速小鼠动脉粥样硬化的提前发生。代谢方式的转变是调控T细胞激活的新方式。但是，细胞代谢重塑是否参与HHcy对免疫细胞的激活过程尚不完全清楚。本项目在预实验基础上，结合对HHcy小鼠动物模型和临床病人研究，从细胞代谢的新角度，利用高通量代谢组学、细胞和分子生物学及免疫学研究手段，揭示糖酵解限速酶PKM2介导HHcy促进细胞糖-脂代谢重塑而激活T淋巴细胞的分子调控机制；在目前已取得的PKM2抑制剂（紫草素）的预实验结果基础上，将利用已成功制作的T细胞特异性敲除PKM2(lck-Cre PKM2 fl/fl)小鼠进行细胞特异性在体和离体干预，确证PKM2介导HHcy引起T细胞激活而加速小鼠动脉粥样硬化的提前发生。该研究成果将为T淋巴细胞激活的相关炎症免疫疾病提供新的干预策略。

免疫炎症引起的血管损害是动脉粥样硬化发病的关键。高同型半胱氨酸血症(HHcy)是动脉粥样硬化的独立危险因素。本项目结合对HHcy小鼠动物模型和临床病人研究，从细胞代谢的新角度，利用高通量代谢组学、细胞和分子生物学、免疫学和T细胞特异性敲除PKM2(lck-Cre PKM2fl/fl)小鼠等研究手段，确证糖酵解限速酶PKM2介导糖脂代谢重塑而激活T淋巴细胞过度增殖和分泌致炎性细胞因子，最终阐明PKM2介导HHcy引起T细胞激活而加速小鼠动脉粥样硬化的提前发生的机制。再此基础上，我们还在炎症免疫性疾病AAA等模型中发现：B细胞来源的特异性抗体加速HHcy促进的AAA；T细胞来源的外泌体促进B细胞致病性抗体的分泌，继而促进动脉粥样硬化的发生；除此之外，我们还在HHcy促进血小板激活等方面取得了原创性研究结果。该申请项目是深对HHcy 促进动脉粥样硬化等炎症免疫发病的新机理的深化理解，也为炎症免疫性疾病提供新的思路和有效干预策略。