BACKGROUND Treatment of Crohn's disease (CD) remains to be a challenge due to limited insights for its pathogenesis. We aimed to determine the role of O-Linked β-N-acetylglucosamine (O-GlcNAc) in the development of CD and evaluate therapeutic effects of O-GlcNAc inhibitors on CD. METHODS O-GlcNAc in intestinal epithelial tissues of CD, adherent-invasive Escherichia coli (AIEC) LF82-infected cells and mice was determined by immunoblot and immunohistochemistry. AIEC LF82 and dextran sulfate sodium were administrated into C57BL/6 mice for estabolishing inflammatory bowel disease model and for therapeutic study. FINDINGS O-GlcNAc was increased in intestinal epithelial tissues of CD patients and AIEC LF82-infected mice. Infection of AIEC LF82 up-regulated the level of UDP-GlcNAc and increased O-GlcNAc in human colon epithelial HCT116 and HT-29 cells. We identified that IKKβ and NF-κB were O-Glycosylated in AIEC LF82-treated cells. Mutations of IKKβ (S733A) and p65 (T352A) abrogated the O-GlcNAc in IKKβ and NF-κB and inhibited AIEC LF82-induced activation of NF-κB. Application of 6-diazO-5-oxO-L-norleucine, an agent that blocks the production of UDP-GlcNAc and inhibits O-GlcNAc, inactivated NF-κB in AIEC LF82-infected cells, enhanced the formation of autophagy, promoted the removal of cell-associated AIEC LF82, alleviated intestinal epithelial inflammation, and improved the survival of the colitis mice. INTERPRETATION Intestinal inflammation in CD is associated with increased O-GlcNAc modification, which is required for NF-κB activation and suppression of autophagy. Targeting O-GlcNAc could be an effective therapy for inflammatory bowel disease. FUNDING National Natural Science Foundation of China (Nos. 81573087 and 81772924) and International Cooperation Foundation of Jilin Province (20190701006GH).

中文翻译：

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克罗恩病中增强的O联糖化酰化作用促进了肠道炎症。

背景技术由于对克罗恩病（CD）的发病机理的了解有限，因此对克罗恩病（CD）的治疗仍然是一个挑战。我们旨在确定O-连接的β-N-乙酰氨基葡萄糖（O-GlcNAc）在CD发育中的作用，并评估O-GlcNAc抑制剂对CD的治疗作用。方法采用免疫印迹和免疫组化方法检测CD，粘附侵袭性大肠杆菌（AIEC）LF82感染的细胞和小鼠肠道上皮组织中的O-GlcNAc。将AIEC LF82和硫酸右旋糖酐钠用于C57BL / 6小鼠，以建立炎症性肠病模型和进行治疗研究。结论CD患者和AIEC LF82感染小鼠的肠上皮组织中O-GlcNAc含量增加。AIEC LF82的感染上调了人结肠上皮HCT116和HT-29细胞中UDP-GlcNAc的水平并增加了O-GlcNAc。我们确定，在AIEC LF82处理的细胞中，IKKβ和NF-κB被O-糖基化。IKKβ（S733A）和p65（T352A）的突变消除了IKKβ和NF-κB中的O-GlcNAc，并抑制了AIEC LF82诱导的NF-κB活化。在AIEC LF82感染的细胞中应用6-diazO-5-oxO-L-正亮氨酸可阻止UDP-GlcNAc的产生并抑制O-GlcNAc的灭活NF-κB，增强自噬的形成，促进其去除与细胞相关的AIEC LF82可以减轻肠道上皮的炎症，并改善结肠炎小鼠的存活率。解释CD中的肠道炎症与O-GlcNAc修饰增加有关，这是激活NF-κB和抑制自噬所必需的。靶向O-GlcNAc可能是治疗炎症性肠病的有效方法。国家自然科学基金（No. 81573087和81772924）和吉林省国际合作基金会（20190701006GH）。