蛋白质泛素化调控抗真菌免疫反应的分子机制研究

黏膜免疫在机体抵抗真菌感染中发挥重要作用。真菌感染后，黏膜免疫细胞表面的C型凝集素受体（c-type lectin receptor，CLR）识别真菌细胞壁的保守成分，启动机体抗真菌免疫反应，但抗真菌免疫反应的调控机制有待深入研究。前期工作中，我们对调控抗真菌免疫反应的泛素连接酶和去泛素化酶进行了初步筛选，发现巨噬细胞或树突状细胞敲除TRIM31和OTUD1后，各种CLR配体所诱导的炎性细胞因子的表达明显降低；白色念珠菌感染后，TRIM31和OTUD1基因敲除小鼠生存率显著下降，脏器中白色念珠菌载量增加，血清中炎性细胞因子的表达显著下降。本课题将利用免疫学、分子生物学、生物化学以及细胞生物学等学科技术手段，深入探讨TRIM31和OTUD1在抗真菌免疫反应中的调控功能及其作用机制，进而揭示蛋白质泛素化调控抗真菌免疫反应的分子机制，为抗真菌药物设计以及临床防治真菌感染性疾病提供新的策略。

Mucosal immunity plays essential role against fungal infections. Upon fungal infections, C-type lectin receptors (CLRs) expressed on innate immune cells recognize conserved constituents of the fungal cell wall and initiate host antifungal immunity. Despite the CLRs signaling transductions has been intensively studied, the regulatory mechanisms responsible for host antifungal immune responses need to be intensively investigated. In our preliminary results, we screened a series of E3 ubiquitin ligases and deubiquitinating enzymes (DUBs) and identified the E3 ubiquitin ligases TRIM31 and DUBs OTUD1, as regulators in antifungal immune responses. After challenged with various ligands for CLRs, the production pro-inflammatory cytokines was markedly reduced in TRIM31-/- and OTUD1-/- BMDMs or BMDCs. TRIM31-/- and OTUD1-/- mice showed higher mortality than WT littermates when challenged with a lethal dose of C. albicans and the fungal burdens in affected organs were significantly increased. Moreover, production of pro-inflammatory cytokines in the serum were decreased in TRIM31-/- and OTUD1-/- mice. In this proposal, we will utilize various molecular techniques to explore the physiological functions of TRIM31 and OTUD1 in the regulation of antifungal immunity and uncover the molecular mechanisms of protein ubiquitination in host antifungal immunity. This study will shield light on the regulation of antifungal immune responses by protein ubiquitination and provide clues for the design of new antifungal drugs, and therapeutic strategies for the protection and treatment of fungal infection-related diseases.