巨噬细胞源外泌体介导自噬障碍致糖尿病肾脏炎症及纤维化机制研究

Macrophages playe an important role in the inflammation and fibrosis of diabetic nephropathy (DN) , but the mechanism remains unclear. We have previously demonstrated that there was interaction between macrophages and renal resident cells, but whether there was interaction between macrophages that amplified inflammatory effects was an urgent problem to be solved.Recently reported exosome as a intercellular signal transduction medium,targeted the autophagy gene through microRNA, but the exosome-autophagy pathway had not been reported in DN.In our previous study, the extracted exosome from high glucose stimulated macrophages supernatant suppressed macrophages autophagy, induced macrophages activation and transdifferentiation to myofibroblasts. We hypothesized that high glucose stimulated macrophage-derived exosome mediated surrounding macrophages autophagy deficiency，activation and transdifferentiation to myofibroblasts . In this proposal, we applied high glucose stimulated-macrophages exosomes in diabetic models which were induced in lysM-Cre-/-Atg7flox/flox and lysM-Cre+/-Atg7flox/flox mice with or without rapamycin treatment. Primary macrophages from lysM-Cre-/-Atg7flox/flox and lysM-Cre+/-Atg7flox/flox mice were used to investigate the effects of macrophage-derived exosomes mediated autophagy deficiency regulating renal surrounding macrophages activation and transdifferentiated into myofibroblasts. Our study provide scientific basis and a novel therapeutic target for inflammation and fibrosis in DN.

巨噬细胞在糖尿病肾病（DN）炎症及纤维化中起重要作用，但机制尚待进一步阐明，我们以前证实巨噬细胞与肾脏固有细胞之间存在相互作用，但巨噬细胞之间是否存在相互作用致炎症作用放大是一个亟待解决的课题。外泌体是一种新的细胞间信息传递方式，通过microRNA靶向自噬基因，但外泌体-自噬途径在DN尚未见报道。我们前期研究中将高糖刺激巨噬细胞上清液中提取的外泌体作用于小鼠巨噬细胞，可见巨噬细胞自噬障碍及活化与转分化。我们假设高糖微环境可能通过改变巨噬细胞源外泌体microRNA，下调自噬诱导周围巨噬细胞激活及转分化，最终导致糖尿病肾脏炎症及纤维化。本项目拟利用高糖刺激巨噬细胞源外泌体于糖尿病、Atg7敲基因、雷帕霉素动物模型以及上述小鼠原代细胞，探讨高糖环境肾内巨噬细胞外泌体介导自噬障碍调控周围巨噬细胞的激活及转分化机制，为临床防治DN炎症及纤维化提供科学依据。

巨噬细胞在糖尿病肾病（DN）的炎症及纤维化中起重要作用，除了介导炎症介质释放外，是否具有其他机制尚待进一步阐明；我们前期实验已经证实巨噬细胞与肾脏固有细胞之间存在相互作用，但其机制有待进一步阐明。外泌体是一种新的细胞间信息传递方式，已有大量研究证实外泌体可以通过携带各类信息物质，包括mRNA、miRNA及蛋白质等进入靶细胞，并影响其功能。自噬是一种自我保护机制，其稳态在DN的疾病进展中有着至关重要的作用，但巨噬细胞源外泌体对肾脏内细胞自噬活性的研究暂无报道。在本研究中，我们发现高糖刺激的巨噬细胞释放的外泌体，可以影响周边正常的巨噬细胞，诱导其活化及炎症反应。不仅如此，外泌体还可以被肾脏固有细胞摄取，如系膜细胞和肾小管上皮细胞，诱导其功能变化及炎症加重。我们通过进一步研究探讨其机制，发现这种现象与外泌体内成分的变化相关。高糖可以通过刺激巨噬细胞释放外泌体，并包裹过量的蛋白质、mRNA和miRNA等进入靶细胞，导致靶细胞的自噬失衡及信号激活，引起肾脏内细胞的异常增殖或损伤及炎症增加。综上所述，我们的研究丰富了巨噬细胞在DN中的作用，也为疾病的诊治提供了新的思路。