5’-AMP调控EAM小鼠心肌浸润巨噬细胞再编程促进炎症消退的机制研究

An inflammatory dilated cardiomyopathy (iDCM) that develops from myocarditis has been shown to be an important cause of heart failure and sudden death; experimental autoimmune myocarditis (EAM) has been widely used as a valid model from myocarditis to developing iDCM. In our previous studies, macrophages (Mφ) play important roles in inflammatory injury, resolving inflammation, and progression to iDCM. 5’-AMP reduced LPS/INF-γ-induced high expression of TNF-α in Mφ, inhibiting the reprogramming of Mφ into inflammatory Mφ. These results suggested that 5’-AMP reprograms the functions of cardiac infiltrating Mφ, leading to pro-resolving inflammation, and delay the development of EAM. In this project, we will investigate the effects of 5’-AMP on Mφ reprogramming and explore the molecular mechanisms in vitro. In vivo, we will investigate the mechanisms for pro-resolving inflammation by 5’-AMP in mice with EAM, which are macrophage ablation in CD11b-diphtheria toxin receptor transgenic mice. This project will indicate a potential preventive and therapeutic strategy for myocarditis, and our findings will be important to further understanding of the functions of purinergic signaling in immunoregulation.

由心肌炎发展来的炎性扩张性心肌病（iDCM）是导致心衰、猝死的重要原因，适时的控制炎症的消退成为控制心肌炎向iDCM进展的关键；实验性自身免疫性心肌炎（EAM）是研究由心肌炎演变为iDCM的有效模型。前期研究证实巨噬细胞（Mφ）在EAM炎症损伤、炎症消退以及向iDCM进展过程中扮演着重要的角色；预实验显示，5’-AMP抑制LPS/INF-γ诱导的TNF-α mRNA高表达，影响Mφ向炎性Mφ再编程，基于此提出“5’-AMP重塑心肌浸润Mφ功能，诱导炎症主动消退，延缓EAM进程”的假说。为证实这一假说，体外阐明5’-AMP对Mφ再编程的影响及其分子机制，体内通过使用CD11b-DTR巨噬细胞消融型小鼠以及5’-AMP的干预进一步阐明5’-AMP在EAM炎症消退过程中的机制。通过上述研究有望为心肌炎的防治提供新思路，并为嘌呤核苷酸在免疫调节中的作用提供新的研究方向。

适时的炎症消退是改善炎性疾病的关键，巨噬细胞（Mφ）在炎症损伤及炎症消退中均扮演着重要的角色。在局部组织微环境调控下，促进炎性型Mφ向炎症消退/组织修复型再编程，有助于延缓炎性疾病进程。本项目研究了外源性5’-AMP对Mφ再编程的影响及其分子机制。体外研究证实，外源性5’-AMP抑制LPS诱导的Mφ向炎性型再编程、降低Mφ胞内ROS水平、抑制Mφ糖酵解代谢；5’-AMP对Mφ再编程的影响是通过调控Mφ关键转录因子STATs实现的，5’-AMP通过CD73/A2AR/cAMP/PKA信号通路升高STAT3磷酸化水平、通过ERK和JNK信号通路抑制STAT1磷酸化水平。体内研究表明，小鼠心肌梗死模型中，外源性5’-AMP抑制心脏组织的炎症反应；实验性自身免疫性心肌炎模型中，5’-AMP促进炎症消退的作用不明显；内毒素血症模型中，5’-AMP能显著提高小鼠生存率，其机制是通过调控巨噬细胞功能表型实现的。5’-AMP作为一种内源性分子，是一种潜在的促消退介质，本项目为后续药物研发提供了实验数据支撑。本项目的研究对于深入理解腺嘌呤核苷酸及其代谢在免疫调节中的作用有着重要的意义。