Lu Ying, Wu Bo, Wang Weipeng, Peng Shicheng, Wang Ying, Xiao Yongtao
Division of Pediatric Gastroenterology and Nutrition, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, No. 1665, Kong Jiang Road, Shanghai, China.
Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China.
Probiotics Antimicrob Proteins. 2024 Dec 26. doi: 10.1007/s12602-024-10425-x.
An elevated abundance of Escherichia coli (E. coli) has been linked to the onset and progression of inflammatory bowel disease (IBD). Regenerating islet-derived family member 4 (Reg4) has been isolated from patients with ulcerative colitis (UC), but its functions and involved mechanisms in intestinal inflammation are remain incompletely understood. Therefore, we generated an intestinal conditional Reg4 knockout mouse (Reg4) to address this gap by utilizing murine models of enteropathogenic E. coli (EPEC)-infected bowel and dextran sulfate sodium (DSS)-induced colitis. We here demonstrate that REG4 is increased in diseased intestinal mucosa of pediatric IBD, primarily expressed and enriched in intestinal goblet cells. Deficiency of Reg4 in the intestinal epithelium of mice leads to an increase in the Phylum Proteobacteria and in the family Enterobacteriaceae. Administration of recombinant Reg4 protein significantly mitigates EPEC-induced intestinal inflammation and injury in a murine model. In vitro, Reg4 protein suppresses the growth and motility of EPEC, subsequently reducing their adhesion and invasion to the intestinal epithelial cells. Mechanistically, the conserved mannan-binding sites (like C-lectin domain) are essential for Reg4 antimicrobial activity. Moreover, loss of Reg4 in mice increases susceptibility to DSS-induced colitis, which can be improved by gentamicin (GM), an antibiotic for Gram-negative bacteria. In conclusion, intestinal goblet cell-derived Reg4 is crucial for protection against experimental colitis, likely due to its bactericidal activity against EPEC.
大肠杆菌（E. coli）丰度升高与炎症性肠病（IBD）的发生和进展有关。再生胰岛衍生家族成员4（Reg4）已从溃疡性结肠炎（UC）患者中分离出来，但其在肠道炎症中的功能和相关机制仍不完全清楚。因此，我们通过利用肠致病性大肠杆菌（EPEC）感染肠道和葡聚糖硫酸钠（DSS）诱导结肠炎的小鼠模型，构建了肠道条件性Reg4基因敲除小鼠（Reg4）来填补这一空白。我们在此证明，REG4在小儿IBD病变肠道黏膜中增加，主要在肠道杯状细胞中表达和富集。小鼠肠道上皮中Reg4的缺乏导致变形菌门和肠杆菌科细菌增加。在小鼠模型中，给予重组Reg4蛋白可显著减轻EPEC诱导的肠道炎症和损伤。在体外，Reg4蛋白抑制EPEC的生长和运动，随后减少其对肠道上皮细胞的粘附和侵袭。从机制上讲，保守的甘露聚糖结合位点（如C型凝集素结构域）对Reg4的抗菌活性至关重要。此外，小鼠中Reg4的缺失增加了对DSS诱导结肠炎的易感性，而庆大霉素（GM）（一种针对革兰氏阴性菌的抗生素）可改善这种情况。总之，肠道杯状细胞衍生的Reg4对预防实验性结肠炎至关重要，可能是由于其对EPEC的杀菌活性。
