NFAT5/CCL2轴调控巨噬细胞M2型极化在心肌梗死后血管再生中的作用及机制研究

The M2 polarization of macrophage plays an important role in the process of revascularization and cardiac function repair after MI. Nuclear factor of activated T cells 5 (NFAT5) is a transcription factor that is sensitive to high salt and hypertonic microenvironment. Studies have demonstrated that NFAT5/ chemokine ligand 2 (CCL2)axis play important role in regulating M2 polarization of macrophage. Our previous work showed that NFAT5 expression was significantly elevated in mouse infarct tissue and macrophages under hypoxic conditions. Meanwhile, we also found that NFAT5 regulated M2 macrophage infiltration via CCL2, in order to regulate collateral artery formation and angiogenesis in rat. However, little is known for the effects of NFAT5 in MI. Therefore, we will first to investigate the role of NFAT5/CCL2 axis in the M2 polarization of macrophage and revascularization after MI in mice, with the use of adenovirus-mediated NFAT5 overexpression or knockdown and CCL2 neutralizing antibody. Secondly, we will also explore the role of NFAT5/CCL2 axis in regulating the M2 polarization of macrophage at the cellular level, using hypoxia-treated macrophages to simulate MI status. This project is expected to expand our understandings of the mechanism of revascularization after MI, and provide a new experimental basis for the development of pro-angiogenic drugs after MI.

巨噬细胞M2型极化在心肌梗死后的血管再生和心功能修复过程中扮演着重要作用。活化T细胞核因子5（NFAT5）是一种高盐敏感性的转录因子，研究表明NFAT5/趋化因子配体2（CCL2）轴在调控巨噬细胞M2型极化过程发挥重要作用。我们前期的研究发现小鼠心梗组织和低氧培养的巨噬细胞中NFAT5表达显著上调，且NFAT5以CCL2依赖方式调控M2型巨噬细胞浸润促进大鼠侧枝动脉生成和血管新生，但目前尚无NFAT5在心肌梗死中的研究。本项目拟在动物实验中利用腺病毒介导的NFAT5过表达或敲低表达，同时利用CCL2中和抗体，探讨NFAT5/CCL2轴在心肌梗后对巨噬细胞M2型极化及血管再生的调控作用；在细胞实验中利用低氧处理巨噬细胞模拟心肌缺氧状态，探讨NFAT5/CCL2轴调控巨噬细胞M2型极化的作用及机制。本研究将有望加深我们对心梗后血管再生机制的理解，为促进心梗后血管再生药物的研发提供新的实验依据。

巨噬细胞M2型极化在心肌梗死后的血管再生和心功能修复过程中发挥着重要作用。活化T细胞核因子5（NFAT5）是一种高盐敏感性的转录因子，研究表明NFAT5/趋化因子配体2（CCL2，也称为MCP-1）轴在调控巨噬细胞M2型极化过程发挥重要作用。在本项目资助下，我们通过在体实验和离体实验的研究，发现心梗和缺氧均可激活NFAT5/MCP-1轴，同时还可诱导巨噬细胞M2型极化；利用腺相关病毒介导的NFAT5 shRNA干预小鼠，可显著抑制心梗后的血管再生、巨噬细胞M2型极化，同时扩大梗死面积；利用NFAT5 siRNA干预巨噬细胞，发现NFAT5敲低可显著抑制低氧诱导的MCP-1表达及巨噬细胞M2型极化。本项目的研究结果表明，NFAT5可通过MCP-1调控巨噬细胞M2型极化，从而影响心梗后的血管再生。此外，在本项目资助期间，我们还进行了心肌梗死相关的其它研究，发现omentin-1通过抑制p38 MAPK/CREB通路改善EPCs功能、抑制颈动脉损伤后的内膜新生；lncRNA-ANRIL通过靶向AKT信号通路促进心梗后的血管新生和改善心功能。本项目及其它相关研究结果有望为阐明心梗后血管再生的机制，以及心肌修复的防治和相关药物研发提供理论依据和新的潜在靶点。