TREM-1 介导 PGLYRP1加重心肌缺血再灌注损伤作用及其机制研究

Activation of innate immunity receptors is closely involved in the myocardial ischemia-reperfusion injury (MIRI). The present study have uncovered that the expression of TREM-1, an innate immunity receptor, was significantly increased in myocardial tissue of MIRI mice model. The similar result was observed in cardiomyocytes experienced hypoxia-reoxygenation. The expression of markers reflecting Inflammation and abnormal autophagy was dramatically attenuated in TREM-1 knockout mice, relative to wide-type mice. We found that PGLYRP1 robustly bound to TREM-1 in vitro, using immunoprecipitation followed by mass spectrometry. Notably, the expression of PGLYRP1 was also increased in MIRI mice model and in cardiomyocytes experienced hypoxia-reoxygenation. Recombinant PGLYRP1 protein promoted the progress of inflammation and abnormal autophagy. Therefore, we hypothesized that the impact of PGLYRP1 on MIRI might be mediated by TREM-1 through the pathway of inflammation and abnormal autophagy. In the following study, the genetically modified mice (Tg-Trem-1, Trem-1-KO) will be administrated by recombinant PGLYRP1 protein and PGLYRP1 antibody, respectively. The cytokines and other markers, involved in the pathway of inflammation and autophagy will be tested.

固有免疫受体介导的炎症和异常自噬与心肌缺血再灌注损伤 (MIRI) 关系密切。我们发现在MIRI小鼠心肌组织和缺氧复氧心肌细胞中，固有免疫受体TREM-1表达增高。TREM-1-KO小鼠MIRI后和心肌细胞缺氧复氧后，炎症和异常自噬显著降低。通过免疫沉淀质谱分析发现并证实PGLYRP1与TREM-1紧密结合。 PGLYRP1在MIRI小鼠心肌组织和缺氧复氧心肌细胞中表达上调，血清PGLYRP1水平与心梗后心衰患者心功能显著负相关。PGLYRP1重组蛋白加剧缺氧复氧后心肌细胞炎症和异常自噬。结合文献提示PGLYRP1经TREM-1介导促进MIRI。后续将用PGLYRP1重组蛋白和中和抗体干预Tg-TREM-1、TREM-1-KO和野生型小鼠，从动物层面和细胞层面探讨TREM-1和PGLYPR1与MIRI的关系，阐明相应机制。

固有免疫受体介导的炎症和异常自噬与心肌缺血再灌注损伤关系密切。既往文献报导固有免疫受体髓样细胞触发受体1（TREM1）参与促进心肌梗死的病理生理机制。肽聚糖识别蛋白1（PGLYRP1）已证实可以在体外与TREM1稳定结合。因此我们猜想PGLYRP1作为TREM1的配体，可能参与心肌缺血再灌注损伤和心肌梗死的的过程。在一个医院人群中，我们采用ELISA检测176名接受冠脉造影患者的血浆，结果显示1个单位PGLYRP1水平的升高导致57%心肌梗死风险增高 (95%CI 0.60-4.11), 四分位最高位较之于最低位心肌梗死风险增高近3倍（OR:3.14, 95%CI: 0.25-39.1)。我们运用免疫组化，RT-PCR，Western blot等技术证明TREM1与PGLYRP1在缺血再灌注小鼠心肌组织和缺氧复氧心肌细胞中表达上调。在心梗组织中，PGLYRP1主要表达于巨噬细胞，同时PGLYRP1在炎症刺激下表达量上调。PGLYRP1重组蛋白摄入显著降低缺血再灌注/心梗小鼠左心室射血分数，并扩大心肌梗死范围。这些结果提示PGLYRP1可能参与了心肌缺血再灌注损伤的发生发展，为PGLYRP1成为心梗和缺血再灌注损伤的治疗靶点提供了理论依据。