TNFR2介导Treg调控多发性硬化发病的分子机制研究

多发性硬化（MS）可导致严重神经功能障碍，但其机制尚不明确，调节性T细胞（Treg）在维持免疫稳态、防止自身免疫病中至关重要。申请者用Tnfrsf1b（编码TNFR2）敲除小鼠发现TNFR2可促进Treg的增殖等，还发现在MS小鼠中Treg的TNFR2表达下调，且TNFα促进Treg的AKT和STAT5磷酸化。由此提出假说：炎症环境下Treg的TNFR2表达下降，影响AKT-STAT5等信号通路，导致Treg的功能受损，不能有效抑制过度免疫反应，进而导致MS发生。本项目将应用FoxP3-Cre:Tnfrsf1bfl/fl小鼠选择性敲除Treg的TNFR2基因，诱导MS鼠模型，采用免疫荧光、体视学定量分析、TMT/iTRAQ等技术探讨Treg的TNFR2缺失对MS进展、Treg活动及其下游信号通路的影响，并从临床样本中进行验证，阐明MS发病的分子机制，为临床靶向精准治疗MS提供新的理论基础。

Multiple sclerosis (MS) can cause severe neurological dysfunction, but its pathogenesis remains clear. Regulatory T cell (Treg) is essential in maintaining immune homeostasis and preventing autoimmune diseases. We used Tnfrsf1b (encoding TNFR2) gene knockout mice to study MS. We found that TNFα promotes Treg proliferation and function through TNFR2, while in MS mouse models, the expression of TNFR2 on Treg decreases dramatically. We also found that TNFα promotes phosphorylation of AKT and STAT5 in Treg. Therefore, we hypothesized that the level of TNFR2 on Treg in an inflammatory microenvironment, and the AKT-STAT5 signaling pathway in the downstream of TNFR2 is not fully activated, which hampers the suppressive function of Treg, and finally cannot suppress the overreactive immune responses. It may be one of the pathogenesis of MS. To prove this hypothesis, we will use Foxp3-Cre:Tnfrsf1bfl/fl mice to conditionally knock out the TNFR2 gene in Treg, then induce the mouse into MS model. We will use immunofluorescence, stereoscopic quantitative analysis, TMT/iTRAQ and other technologies, to observe the effect of TNFR2 deletion on MS clinical cause, Treg proliferation and function and its downstream signaling pathways. We also will verify this hypothesis on MS patients. This research will clarify the effect and molecular mechanisms of TNFR2's influence on Treg in MS with a new perspective, and provide a new theoretical basis for clinical targeted treatment of MS.