miR-301a-3p和miR-22a-3p在实验性自身免疫性葡萄膜炎中对Th17细胞的调控及机制

Uveitis is a group of diseases causing serious impairment of visual function. However, the mechanisms involved in the development of autoimmune uveitis are still not completely understood. Recent work have revealed that IL-17 producing Th17 cells are critical mediators of autoimmune uveitis. Although many Th17-specific mediatiors of phthogenesis have been identified, the role of microRNAs that control IRBP-specific Th17 cells, and whether targeting microRNAs can have therapeutic effects remain unclear. Our preliminary studies showed that miR-301a-3p and miR-22a-3p are closely related with the function of IPBP-Th17 cells. Based on our preliminary data and the latest progress in this field, this project will investigate mechanisms of miR-301a-3 and miR-22a-3p regulating IRBP-specific Th17 cells in experimental autoimmune uveitis induced by active immunization or adoptive transfer of active IRBP-specific T cells, verify the target genes of miR-301a-3p and miR -22a-3p and elucidate the signaling pathway of miR-301a-3p and miR-22a-3p regulating IRBP-Th17 cells. The therapeutic effects of down-regulation of miR-301a-3p and miR-22a-3p on EAU will also be studied. These will shed further light on the mechanisms driving human uveitis, and will provide strong theoretical basis as well as standardized technology platform for developing novel strategies for prevention and treatment of autoimmune uveitis.

葡萄膜炎是一类严重损害视功能的疾病，其尚未完全明了的发病机制局限了其有效治疗。目前认为，IRBP-Th17细胞在实验性自身免疫性葡萄膜炎中（EAU）起着重要的作用, 但微小RNA在EAU中对致病性Th17细胞的作用尚不完全清楚。我们前期研究发现，miR-301a-3p 和miR-22a-3p与IRBP-Th17细胞功能密切相关。结合前期研究和最新进展，本课题将通过不同的EAU动物模型首次研究葡萄膜炎相关微小RNA（miR-301a-3p和miR-22a-3p）对Th17细胞的调控及机制，探讨其在EAU发生中的作用，明确其对免疫细胞群特别是对Th17细胞的影响；通过研究他们的靶基因及下游基因，分析其参与Th17细胞分化的信号通路；研究对比疾病不同时期、不同的方式下调其活性对EAU的治疗效果。本项目的开展有利于进一步阐明葡萄膜炎的发病机理，也将为临床葡萄膜炎的治疗提供新的思路和坚实的理论基础。

自身免疫性葡萄膜炎是常见的致盲性眼病。其确切的病因和发病机制尚未完全阐明，限制了其有效治疗方法的发展。研究表明，致病性Th17细胞在实验性自身免疫性葡萄膜炎（EAU）中发挥重要作用，但微小RNA在EAU中对致病性Th17细胞的调控及机制尚不清楚。本课题中，我们采用基因芯片筛选致病性Th17细胞中差异表达的微小RNA，发现miR-223-3p和miR-22-3p显著上调，而miR-181a-5p显著下调，Q-PCR进一步验证了该结果。为明确这些微小RNA对EAU病程及免疫细胞群的影响，我们采用miR-223-3p，miR-22-3p和miR-181a-5p过表达慢病毒侵染C57BL/6小鼠，IRBP主动免疫诱导EAU，并进行临床、组织病理学和免疫学的检测，发现体内过表达miR-223-3p及miR-22-3p可促进EAU进程，增强致病性Th17细胞反应，而过表达miR-181a-5p可减缓EAU进程，抑制致病性Th17反应。利用T细胞介导的过继转移模型，我们证实T细胞中敲低miR-223-3p可降低Th17细胞的致病性，减缓EAU进程。机制研究证明，miR-223-3p直接抑制FOXO3的表达，而FOXO3通过部分抑制IL-23R的表达负调控致病性Th17细胞反应。为了将我们在小鼠中的结果外推到人类受试者，我们分析了从Gene Expression Omnibus数据库获取的葡萄膜炎患者和健康志愿者基因表达谱原始数据，发现人类葡萄膜炎中FOXO3与Th17通路呈负相关。因此本研究证明miR-223-3p/Foxo3/IL-23R轴可能是干预和治疗葡萄膜炎的潜在靶点。