调节T细胞（Tregs）辅助的巨噬细胞胞葬对骨骼肌炎症调控及其机制研究

急性创伤或过度运动导致的剧烈炎症和肌坏死频繁发生。近期研究指出，调节T细胞（Tregs) 辅助的巨噬细胞胞葬有助组织炎症消退。我们前期研究发现，肌纤维TGF-β信号缺失会加剧肌损伤炎症，导致肌内巨噬细胞渗出增多、Tregs减少、凋亡细胞聚集。因此，本项目拟采用Cardiotoxin诱导肌纤维TGF-β条件敲除鼠（SM TGF-βrII-/-)、肌纤维携带OVA抗原且TGF-β缺失的双转基因鼠（SM-TGFβrII-/-/SM-OVATg）肌损伤，辅以体内Tregs灭活/重构，Tregs、巨噬细胞、肌纤维体外共培养，以及OT-I/II细胞移植，检测损伤肌内巨噬细胞胞葬相关细胞和分子表型，分析肌内炎性环境能否触发Tregs-IL-13-巨噬细胞-IL-10-Vav1-Rac1胞葬信号，以及内源TGF-β信号通过影响肌纤维免疫行为对该胞葬途径的干预。

It has been reported that, Treg cells boost efferocytosis by macrophages, which is a critically important effector arm of inflammation resolution. Recently, we found that, in mutant mice, deficiency of TGF-β signaling in muscle cells caused more serious muscle inflammation, with an increased number of macrophages and decreased number of Treg cells. In addition, apoptotic cells accumulation can be observed in inflamed muscle. We thus assume that, after myoinjury, TGF-β signaling is activated in regenerating myofibers, which promotes IL-13 secretion by myofibers or Treg cells, and finally triggers IL-10-Vav1-Rac1signal in macrophages to enhance apoptotic cell engulfment. We will address these in a mouse tibialis anterior muscle cardiotoxin injection-induced injury repair model in control or transgenic mice with or without TGF-β receptor II being specifically deleted in muscle cells (SM TGF-βrII-/-), and in double transgenic mice with TGF-βrII knocking in myofibers and with expression of OVA as a self-antigen in skeletal myofibers (SM-TGF-βrII-/-/SM-OVA Tg). As well, the co-culture of Treg cells and macrophages, or primary mice myoblast will be performed in this work. OT-I/II cell transferring into SM-TGF-βrII-/-/SM-OVA Tg mice will be performed to analyze muscle auto-antigen specific T cells reaction. Thus, this work is possible to get information for muscle immune tolerance and myoinjury therapeutic strategy by targeting regulatory T cells-mediated enhancement of macrophage efferocytosis in inflamed muscle.