Glcα1,2Galβ1-糖基化修饰: IL-2/IL-2R介导JAK-STAT信号途径激活的关键？

Th17与Treg平衡失常是自身免疫性肝炎发病的关键环节，但分子机制未知。申请人前期发现Glt25d1介导的Glcα1,2Galβ-糖基化修饰影响Treg分化。在Glt25d1敲除鼠中发现其易发免疫性肝炎，推测可能与Treg减少有关，但详细机制不清。因此，本项目采用刀豆蛋白A制备WT、Glt25d1+/-、Glt25d1ΔCD4小鼠肝损伤模型，检测肝、脾、外周血中Th17/Treg细胞，明确Glt25d1在Th17/Treg平衡中的作用；利用体外原代CD4+ T及Naïve CD4+ T细胞极化模型检测Th17和Treg变化；关注IL-2-JAK-STAT信号的作用，并结合不同糖型的IL-2和IL-2R，明确其糖基化异常是否调控Th17/Treg；利用生物质谱检测细胞糖型。最后研究该糖基化修饰对Treg治疗作用的影响。研究有助于免疫性肝损伤分子机制的阐述及精准干预靶点的筛选。

The abnormal balance of Th17 and Treg has been considered as the key link of the pathogenesis of autoimmune hepatitis (AIH), but its molecular mechanism is unknown. Previously we found that Glcα1,2Galβ-glycosylation mediated by Glt25d1 modulated the differentiation of Tregs. A susceptibility of immune-mediated liver injury was observed in Glt25d1 gene knockdown mice, which might be related to the decrease of Tregs, but the detailed mechanisms were unclear. Therefore, in this study, Concanavalin A was injected to wild type (WT), Glt25d1+/-, and Glt25d1ΔCD4 mice to establish an immune-mediated liver injury model. The frequencies of Th17 and Tregs in liver, spleen and peripheral blood were detected to confirm the role of Glt25d1 in the balance of Th17 and Tregs. Meanwhile, primary CD4+T cells and naïve CD4+T cell polarization models were used to detected the changes of Th17 and Tregs in vitro. Then, the role of IL-2-JAK-STAT signal pathway were detected, and different glycan of IL2 and IL-2R were used to clarify the importance of this glycosylation to the regulation of Th17/Treg. Furthermore, we detected the glycan of cell surface by biological mass spectrometry. Finally, we detected the effect of Glcα1,2Galβ-glycosylation on therapeutic effect of Treg. This study was helpful to elucidate the molecular mechanism of immune-mediated liver injury and the screening of precise intervention targets.