巨噬细胞外泌体miR-155活化口腔肌成纤维细胞NLRP3炎症小体促进口腔黏膜下纤维化的机制

Oral submucous fibrosis (OSF) is a precancerous lesion caused by arecoline. Exosome mediates intercellular communication and plays an important role in the regulation of inflammasome and fibrosis. However, whether OSF has a similar mechanism remains unclear. Previous studies have shown that the increased expression of miR-155 in human oral myofibroblasts (HOMF) is due to arecoline-induced exosome transport of macrophages, and after the overexpression of HOMF miR-155, the expression of NLRP3 and collagen I increase. Therefore, we hypothesize that arecoline induces the secretion of miR-155-enriched exosomes in macrophages, these exosomes are then absorbed by HOMF and promote the activation of NLRP3 inflammasome and collagen production, which eventually leads to OSF. This project aims to analyze the correlation between exosomal miR-155 and clinical characteristics of OSF patients, to verify the regulation of arecoline on macrophage exosomal miR-155, and to explore the effect of macrophage exosomal miR-155 on oral mucosal fibroblasts. The effects of arecoline-induced exosomal miR-155 in THP-1 on the migration、pyroptosis、NLRP3 inflammasome and regulation of collagen in HOMF will be observed in both vivo and vitro, and the possibility of exosome as a therapeutic target will be studied.

口腔黏膜下纤维化（OSF）是由槟榔碱引起的癌前病变。外泌体可介导促纤维化因子引起器官纤维化发生，并在炎症小体的调节及纤维化的网络调控中发挥重要作用，但在OSF是否类似机制有待阐明。本项目前期研究显示人口腔肌成纤维细胞（HOMF）miR-155表达增加缘于槟榔碱诱导的巨噬细胞外泌体传输；HOMF miR-155过表达后，NLRP3及I型胶原增加。我们推测槟榔碱诱导富含miR-155的巨噬细胞外泌体被HOMF摄取后激活NLRP3炎症小体促进胶原生成以及纤维化。本项目拟验证槟榔碱对巨噬细胞外泌体miR-155的调控；探讨巨噬细胞外泌体miR-155对口腔黏膜成纤维细胞功能的影响；分析外泌体miR-155与OSF患者临床特征的相关性。本项目将进一步阐明巨噬细胞外泌体miR-155激活NLRP3炎症小体促进OSF的作用机制，并探讨外泌体作为治疗靶点的价值，为防治OSF提供新的科学依据。

目前研究认为，病理性纤维化与慢性炎症密切相关。尽管已有研究证实槟榔碱可能通过诱导炎症细胞因子的分泌，促进成纤维细胞增殖，但槟榔碱调控炎症细胞的潜在机制及其对下游成纤维细胞的影响方式目前尚未完全阐明。外泌体中所包含的种类丰富的miRNA不仅参与细胞生物功能的调控，还为疾病诊断和预后评估提供了潜在生物标志物，是近年的研究热点。本项目前期研究表明，正常的大鼠口腔黏膜组织成纤维细胞miR-155 表达低；而口腔粘膜下纤维化（OSF）大鼠口腔黏膜组织成纤维细胞miR-155表达显著增高；外泌体阻断剂GW4869 可抑制大鼠口腔成纤维细胞miR-155 表达以及OSF 的发生。槟榔碱可诱导人单核巨噬细胞外泌体中miR-155 含量增高，被人口腔肌成纤维细胞摄取后miR-155 表达增高；人口腔肌成纤维细胞miR-155 过表达后，NLRP3 及胶原蛋白表达增高。我们证实槟榔碱可诱导THP-1细胞分泌富含miR-155-5p的外泌体，该外泌体可进一步被HOMF细胞摄取并促进细胞向成纤维表型转化。这一发现拓展了槟榔碱诱导OSF的发病机制，口腔黏膜下炎症细胞与口腔成纤维细胞间外泌体通讯可能是治疗槟榔碱相关OSF的新靶点。