细胞特异性Met/MetSO酶控平衡对脂质代谢及动脉粥样硬化的干预机制研究

蛋白质中甲硫氨酸（Met）与其氧化产物甲硫氨酸亚砜（MetSO）的可逆转变是一种特殊的氧还修饰调节，细胞特异的甲硫氨酸亚砜还原酶A（MsrA）催化MetSO还原。有证据，Met/MetSO的酶控平衡具有抗氧化应激及调节靶蛋白功能活性的作用，但疾病过程中组织特异性Met氧还修饰靶蛋白特征并不明确。我们前期工作发现，不同手段提高肝细胞、巨噬细胞MsrA活性可显著降低ROS水平、抑制炎症、改善细胞脂质转运功能，并有效减少小鼠动脉粥样硬化（As）斑块，但对不同模型小鼠脂代谢的调控靶点和途径并不一样。故本项目特别构建了MsrA基因敲除小鼠，拟借助慢病毒感染、骨髓移植和硫氧化修饰蛋白组学技术，选择性于肝细胞或巨噬细胞中表达MsrA，探讨在应激下特定细胞Met/MetSO酶控平衡对脂代谢、炎症相关的关键靶蛋白及信号的调控，以期从蛋白质Met氧还修饰角度揭示对As的干预机制，为As抗氧化防治提供新依据。

Oxidation of methionine (Met) and reversible reduction of its oxidized product, methionine sulfoxide (MetSO) in proteins, constitute a special redox regulation, in which MetSO reduction is catalyzed by a specific intracellular enzyme, named as methionine sulfoxide reductase A (MsrA). There is evidence that Met/MetSO enzymatic-controlled equilibrium acts as an important mechanism for protecting cells from oxidative stress and regulation of target protein function. However, the characteristics of target proteins regulated by cell-specific redox modification during the process of disease are not clear. Our previous study showed that different approaches to improve the MsrA activity of hepatocytes or macrophages could significantly decrease reactive oxygen species (ROS) level, inhibit inflammation, improve cellular lipid transport, and obviously reduce atherosclerotic plaques in mouse models, but the targets and pathways for regulating lipid metabolism in different mice were not exactly the same. Therefore, we specially generate MsrA knockout mice as model, MsrA could be specifically expressed in hepatocytes or macrophages by means of lentivirus infection, bone marrow transplantation and redox proteomics of protein-bound Met oxidation, to explore the regulation of cell-specific Met/MetSO enzymatic-controlled equilibrium on the target proteins and signaling pathways which related with lipid metabolism and inflammation under stress. These studies will shed light on the intervention mechanism of atherosclerosis from the perspective of protein Met redox modification, and provide a new basis for the antioxidative strategy in the prevention and treatment of atherosclerotic cardiovascular diseases.