Department of Gastroenterology, The Second Hospital of Hebei Medical University, Shijiazhuang, China.
Department of Gastroenterology, Cedars-Sinai, Medical Center, Los Angeles, California, USA.
IUBMB Life. 2020 Dec;72(12):2686-2695. doi: 10.1002/iub.2406. Epub 2020 Nov 7.
Autophagy-related 16-like 1 (Atg16l1) contributes to the susceptibility to ulcerative colitis (UC). The functional consequences of Atg16l1 in UC pathogenesis are poorly understood. We aimed to confirm how Atg16l1 deficiency in dendritic cells (DCs) affects murine colitis development. Atg16l1 mice and mice with Atg16l1 deficiency in CD11c DCs (Atg16l1 ) were generated for colitis models induction. Disease activity index, weight loss, colon score/length, and histopathological analysis were assessed for colitis severity. Mononuclear cells from mesenteric lymph node (MLN) were extracted for CD44/CD69 measurement by flow cytometry. Bacterial cultures of MLN and stool homogenates were used to evaluate the bacterial translocation. Bone marrow-derived dendritic cells (BMDCs) were isolated and cultured for immunofluorescence of autophagy-related proteins. Atg16l1 knockout in CD11c DCs exacerbated intestinal inflammation of dextran sulfate sodium (DSS)-induced colitis in vivo. Atg16l1 deficiency in CD11c DCs had no effect on the expression of CD44 and CD69. Bacterial translocation showed that bacteria amount in MLN and stool of DSS-induced colitis with Atg16l1 deficiency significantly higher than that of control. Immunofluorescence revealed that Atg16l1 deficiency obviously inhibited co-expression of LC3 and Lamp1 with S. typhimurium, enhanced co-expression of rab5 and rab7 with S. typhimurium, while did not affect Beclin1. We confirmed that Atg16l1 deficiency in DCs exacerbated the intestinal inflammation of DSS-induced colitis. Atg16l1 deficiency in DCs promotes the bacterial translocation of DSS-induced colitis in vivo and regulates autophagy and phagocytosis in BMDCs. Findings provided a novel perspective to study UC pathogenesis.
自噬相关蛋白 16 样蛋白 1（Atg16l1）与溃疡性结肠炎（UC）易感性有关。Atg16l1 在 UC 发病机制中的功能后果尚不清楚。我们旨在确认树突状细胞（DC）中 Atg16l1 缺失如何影响小鼠结肠炎的发展。生成 Atg16l1 敲除小鼠和 CD11c DC 中 Atg16l1 缺失（Atg16l1）的小鼠用于结肠炎模型诱导。通过疾病活动指数、体重减轻、结肠评分/长度和组织病理学分析评估结肠炎严重程度。从肠系膜淋巴结（MLN）提取单核细胞，通过流式细胞术测量 CD44/CD69。使用 MLN 和粪便匀浆的细菌培养物评估细菌易位。分离和培养骨髓来源的树突状细胞（BMDC），用于自噬相关蛋白的免疫荧光。CD11c DC 中 Atg16l1 的缺失加剧了葡聚糖硫酸钠（DSS）诱导的结肠炎体内的肠道炎症。CD11c DC 中 Atg16l1 的缺失对 CD44 和 CD69 的表达没有影响。细菌易位显示 DSS 诱导的结肠炎中 Atg16l1 缺乏的 MLN 和粪便中的细菌数量明显高于对照组。免疫荧光显示 Atg16l1 的缺乏明显抑制了 LC3 和 Lamp1 与鼠伤寒沙门氏菌的共表达，增强了 rab5 和 rab7 与鼠伤寒沙门氏菌的共表达，而不影响 Beclin1。我们证实了 DC 中 Atg16l1 的缺乏加剧了 DSS 诱导的结肠炎的肠道炎症。DC 中 Atg16l1 的缺乏促进了体内 DSS 诱导的结肠炎的细菌易位，并调节了 BMDC 中的自噬和吞噬作用。这些发现为研究 UC 的发病机制提供了一个新的视角。
