调节性T细胞在心肌梗死后巨噬细胞胞葬过程中的作用及机制研究

Inflammation and immunity play important roles in Myocardial infarction. Macrophage efferocytosis play an protective role in myocardial infarction (MI) by resoluting inflammation ,and regulatory T cells (Treg) were proved to reduce inflammation after MI because of their effect in promoting macrophages to M2 polarization. However, little is known about whether Treg cells are involved in the regulation of macrophage efferocytosis. Our preliminary study found that Treg cells can enhance the efferocytosis of macrophage and ameliorate heart function in MI, but the mechanism has not been clarified. Based on this foundation, we attempt to use the mice MI model to study the following contents: Firstly, we will dynamically observe the ability of macrophages to phagocytose apoptotic cells at the different time points. At the same time, mice which were treated with PC61mAb ,Diphtheria toxin ,IL-2C or adoptive transfer Treg cells to Rag-/- mice were used to evaluate the effect of different frequency of Treg cells on the process of macrophage efferocytosis more deeply. Secondly, we will co-culture Treg cells with macrophages in vitro and use the related knockout mice to explore the specific mechanism of Treg cells in promoting macrophage efferocytosis in vitro and in vivo. Through this research, it is expected to elucidate the new mechanism of Treg cells in the protection of MI and improve the theory of MI immunity and inflammation, which provide a new theoretical and experimental basis for MI clinical targeted therapy.

炎症及免疫在心肌梗死（MI）中发挥重要作用。研究证实巨噬细胞胞葬促进炎症消退，保护心功能。调节性T细胞（Treg）促进巨噬细胞M2极化减轻心梗后炎症，但其是否参与调节巨噬细胞胞葬研究甚少。我们研究证实：MI中，Treg细胞促进巨噬细胞胞葬效应，但机制尚未明确。基于此本课题拟以小鼠作为MI模型研究以下内容：1、观察MI不同时间点巨噬细胞胞葬能力，分别使用正常Treg小鼠、Treg消除小鼠（包括使用PC61mAb及Foxp3DTR小鼠）、增加Treg小鼠（IL-2C及Rag-/-小鼠过继转输Treg细胞），探究Treg细胞在巨噬细胞胞葬过程中的作用 2、利用Treg细胞与巨噬细胞共培养及相关敲基因小鼠离体及在体探究Treg细胞促进巨噬细胞胞葬过程的具体机制。通过本课题的研究有望阐明Treg细胞在MI中保护作用的新机制，完善MI免疫炎症理论，为MI临床靶向治疗提供新的理论基础及实验依据。

炎症及免疫在心血管疾病发生发展过程中发挥重要作用。前期研究证实巨噬细胞胞葬作用可促进心肌梗死（MI）后炎症消退，在心肌梗死中发挥保护性作用。调节性T细胞（Treg）是体内重要的免疫调节细胞，其被证实可促进巨噬细胞M2极化减轻MI后炎症。但Treg细胞是否参与调节巨噬细胞胞葬过程则研究甚少。基于此，本课题以小鼠作为MI模型研究了以下内容：1、动态观察不同时间点巨噬细胞吞噬凋亡细胞的能力，分别使用正常Treg小鼠、Treg消除小鼠（包括使用PC61mAb及Foxp3DTR小鼠）、增加Treg小鼠（IL-2-AntiIL-2复合物及Rag-/-小鼠过继转输Treg细胞），进一步探究Treg细胞在巨噬细胞胞葬过程中的作用 2、利用Treg细胞与巨噬细胞体外共培养及相关敲基因小鼠离体及在体探究Treg细胞促进巨噬细胞胞葬过程的具体机制。我们的研究结果显示：MI后第5天巨噬细胞胞葬作用达到最强。消除Treg细胞后巨噬细胞胞葬作用减弱，这一过程与Treg细胞产生的IL-10及TGF-β有关。相反的，增加在体Treg细胞可增强巨噬细胞胞葬作用，其作用也与Treg细胞产生的IL-10及TGF-β有关。机制研究结果显示Treg细胞可以通过产生上述两种细胞因子激活巨噬细胞STAT3-Vac-1-Rac-1通路从而促进巨噬细胞胞葬作用，改善疾病预后。本课题的初步研究结果阐明了Treg细胞在MI中保护作用的新机制，完善了MI免疫炎症理论，为MI临床靶向治疗提供新的理论基础及实验依据。