UFM1修饰调控cGAS-STING信号转导的功能和机制研究

The cGAS–STING signaling pathway plays an important role in anti-microbial innate immunity by recognizing cytosolic DNA from viral, while the improper activation/inactivation of this pathway may lead to autoimmune diseases, so the strength and duration of it should be precisely regulated. However, the manner in which the cGAS–STING signaling pathway is regulated remains not fully understood. In this project, our preliminary results suggested that UFM1 and UFMylation pathway positively regulate the activation of cGAS–STING signaling pathway, and further investigation indicated that STING is modified by UFMylation, with Ufl1 work as the E3 ligase. Based on that, we hypothesized that UFM1 and UFMylation may positively regulate the activation of cGAS–STING signaling pathway by targeting STING. This subject will further explore the modulatory mechanisms of UFMylation on cGAS–STING signaling pathway, as well as the physiological and pathological functions of UFMylation on anti-virus immune responses, which will bring a fresh perspective on the prevention and treatment of diseases related with the cGAS–STING signaling pathway.

cGAS–STING信号通路通过识别细胞胞质中的病毒DNA，在宿主抗感染固有免疫过程中发挥重要的作用。而该通路的失调将导致自身免疫性疾病，因此其在时间与空间上的激活以及失活必须受到精密而严格的调控。然而，cGAS–STING信号通路的调节机制还未完全清楚。本课题前期结果表明：UFM1介导的类泛素化修饰促进cGAS–STING信号通路的激活，并且STING被UFM1修饰，而E3连接酶Ufl1催化该修饰。鉴于此，我们推测UFM1修饰途径通过修饰STING促进cGAS–STING信号通路的激活。本课题将进一步探究UFM1修饰调节cGAS–STING信号通路的分子机制，并揭示其在抗病毒免疫中发挥的病理和生理功能，为预防和治疗与该通路相关疾病提供新的思路。

cGAMP合成酶（cGAS）在机体抗病原体免疫中发挥着重要的作用。鉴于其在固有免疫中的重要作用，cGAS的活性收到了精密而准确的调控，以便维持免疫稳态。本研究中，我们阐述了neddylation修饰在调控cGAS-STING信号通路活性调控中的关键作用。使用neddylation抑制剂MLN4924可显著抑制DNA诱导的I型干扰素好相关炎症介质的表达，敲除neddylation途径的E2 UBE2M也可发挥相同的作用，而敲除另一个E2 UBE2F对cGAS-STING信号通路的激活无影响。我们进一步鉴定RNF111缺失显著抑制DNA诱导的信号通路的激活，而对cGAMP诱导的通路激活无影响，提示RNF111的靶点可能为cGAS。我们进一步证明cGAS可被neddylation修饰，而进一步的质谱实验显示cGAS的231位和421位赖氨酸保守位点可发生neddylation修饰。RNF111促进cGAS的neddylation修饰，并促进cGAS形成同源二聚体并增强cGAS结合DNA的活力，增强cGAS-STING信号通路的激活。最后，我们研究表明敲除RNF111或者UBE2M可抑制机体抗DNA病毒HSV-1感染。因此，本课题揭示了neddylation修饰在cGAS-STING抗病毒信号通路中的关键调控作用。