ATG16L1对实验性结肠炎小鼠树突状细胞功能的调节作用

Inflammatory bowel diseases (IBD) are chronic debilitating inflammatory conditions, which are classically differentiated into Crohn disease (CD) and ulcerative colitis. To date, 200 susceptibility loci have been identified. One of the genes is ATG16L1. Mice with Atg16l1 deficiency in intestinal epithelial cells develop severe ileitis. Additionally, conditional deletion of Atg16l1 in macrophages led to impaired clearance of Yersinia enterocolitica. However, the effect of ATG16L1 in the dendritic cells has not been understood. We generated mice deficient in Atg16l1 in DCs (Atg16l1f/f x DC-Cre). Salmonella acute colitis model and DSS-induced colitis were established. Bone marrow derived dendritic cells (BMDC) were isolated. Autophagy function was assessed with LC3 and P40 immunoblotting. Uptake of Salmonella enterica serovar Typhimurium was assessed by flow cytometry and electron microscopy (EM). Reactive oxygen (ROS) production and intracellular S. typhimurium killing in DCs were assessed. DSS induced colitis and S. typhimurium infection was used to assess the in vivo role of DCs specific Atg16l1 deficiency in murine colitis, which might provide a new evidence for prevention and treatment of IBD.

遗传易感性与免疫失衡是溃疡性结肠炎(UC)的重要发病机制。自噬基因ATG16L1在炎症性肠病(IBD)的免疫调控中发挥重要作用，敲除ATG16L1，则不能有效清除病原体，进而激活炎症反应，导致IBD发生。既往研究已证实ATG16L1对肠道潘氏细胞、上皮细胞的调控作用；最近，我们前期研究发现巨噬细胞ATG16L1特异性完全敲除的小鼠结肠炎症程度明显加重，并且降低了胞内细清除的能力、自噬小体的形成及抗原递呈能力；而对树突状细胞的作用鲜有研究。在本课题中，我们采用树突状细胞特异性ATG16L1敲除小鼠，建立鼠伤寒沙门氏菌感染及DSS诱导的急、慢性实验性结肠炎模型，分离骨髓来源的树突状细胞(BMDC)，通过检测小鼠结肠炎症、BMDC的吞噬能力、清除细菌能力、自噬小体形成及抗原递呈能力研究ATG16L1对DC能的调节作用，探讨DC的自噬作用对小鼠实验性结肠炎的影响，为UC发病机制的研究提供理论依据。

遗传易感性与免疫失衡是溃疡性结肠炎(UC)的重要发病机制。自噬基因ATG16L1在炎症性肠病(IBD)的免疫调控中发挥重要作用，敲除ATG16L1，则不能有效清除病原体，进而激活炎症反应，导致IBD发生。既往研究已证实ATG16L1对肠道潘氏细胞、上皮细胞的调控作用；最近，我们前期研究发现巨噬细胞ATG16L1特异性完全敲除的小鼠结肠炎症程度明显加重，并且降低了胞内细清除的能力、自噬小体的形成及抗原递呈能力；而对树突状细胞的作用鲜有研究。在本课题中，我们采用树突状细胞特异性ATG16L1敲除小鼠，建立鼠伤寒沙门氏菌感染及DSS诱导的急、慢性实验性结肠炎模型，分离骨髓来源的树突状细胞(BMDC)，通过检测小鼠结肠炎症、BMDC的吞噬能力、清除细菌能力、自噬小体形成及抗原递呈能力研究ATG16L1对DC能的调节作用，探讨DC的自噬作用对小鼠实验性结肠炎的影响，为UC发病机制的研究提供理论依据。