转化生长因子-β转基因间充质干细胞治疗实验性自身免疫性葡萄膜炎机制研究

Uveitis is a common sight-threatening ocular disease, to which a safe and effective therapeutic modality is still in urgent need. Our previous studies showed that mesenchymal stem cells (MSCs) could effectively delay the onset and inhibit the development of experimental autoimmune uveitis (EAU) in rat. Based on our preliminary results and the latest progress in this field, this project will investigate the therapeutic effects of TGF-β transgenic MSCs in EAU mice induced by adoptive transfer of IRBP-specific T cells, treated by MSCs at different time points and with different protocol of administration, and the effects of the MSCs on the relapse of EAU caused by uveitogenic T cells will also be studied. The immunomodulatory mechanism of the MSCs will be dissected by detecting the changes of the function and quantity of the three T cell subsets: Th1, Th17, and Treg cells, in the eye, lymph nodes and spleen, and investigating the effects of the MSCs-screted cytokines on them, especially on the balance between Th17 and Treg. The neuroprotective role of TGF-β transgenic MSCs on retinal neural cells will also be evalued. This project will further optimize the therapeutic strategy of MSCs by exploring the possibility of treating EAU with TGF-β transgenic MSCs, and will provide strong theoretical basis as well as standardized technology platform for future clinical translation in ophthamology.

葡萄膜炎是常见的致盲性眼病，寻找安全有效的治疗方法仍是临床亟待解决的问题。我们既往研究表明间充质干细胞（MSCs）可以有效抑制大鼠实验性自身免疫性葡萄膜炎（EAU）的发生发展。结合前期研究和最新进展，本课题将通过小鼠特异性T细胞过继转移诱导的EAU模型，首次研究TGF-β转基因MSCs在不同给药模式和时机下，对EAU的治疗作用及对特异致病性T细胞再致病能力的影响；并通过检测淋巴器官和眼部Th1、Th17及Treg细胞数量和功能变化，以及MSCs细胞因子分泌功能对T细胞亚群，尤其是Th17与Treg细胞平衡的影响，阐明TGF-β转基因MSCs在自身免疫性葡萄膜炎中的免疫调节机理；通过视网膜神经细胞凋亡改变研究其对视网膜可能的神经保护作用。从而探讨其治疗自身免疫性葡萄膜炎的可能性，进一步优化MSCs治疗方案，为MSCs在眼科临床应用的转化提供坚实的理论基础和规范化技术平台。

本研究采用C57BL/6小鼠EAU动物模型，观察TGF-β转基因MSCs对EAU的治疗作用。同时还研究了MSC表面膜蛋白CD73以及MSC分泌的外泌体（exosomes）在介导MSC免疫抑制功能中发挥的作用。结果显示与对照MSCs相比，TGF-β转基因MSCs在EAU治疗作用方面没有优势。其对T细胞抑制作用与对照MSCs相比也没有差异。CD73和exosomes均部分介导MSC的免疫抑制作用，显示MSCs可通过多种模式发挥免疫抑制作用。MSC-exosomes可以作为MSC的替代治疗方法。