Butyrate protects the intestinal barrier by upregulating Fut2 expression via MEK4-JNK signaling pathway activation.

Abstract

Necrotizing enterocolitis (NEC) is a severe gastrointestinal inflammatory disease in neonates. Fucosyltransferase 2 (Fut2) regulates intestinal epithelial cell fucosylation. In this study, we aimed to investigate butyrate-mediated upregulation of Fut2 expression and the underlying mechanisms. In vivo and in vitro models were established. SP600125 was used to inhibit the MEK4-JNK pathway, and anisomycin was used to activate the MEK4-JNK pathway. Fut2, occludin, and ZO-1 expressions were assessed. Furthermore, intestinal permeability was analyzed by FITC-Dextran. The expression of proteins in the MEK-4-JNK pathway was examined by western blotting. In vivo, the addition of exogenous butyrate notably upregulated Fut2, occludin, and ZO-1 expressions and reduced intestinal permeability in mice with NEC. Butyrate may increase the phosphorylation of MEK4, JNK, and c-jun, which are key components of the MEK4-JNK pathway. Additionally, SP600125 inhibited their phosphorylation, which was reversed by anisomycin treatment. In vitro, butyrate substantially increased occludin and ZO-1 expressions. Butyrate considerably increased Fut2 expression and markedly upregulated p-MEK4, p-JNK, and p-c-jun expressions. SP600125 administration decreased their expressions, while anisomycin administration increased their expressions. Butyrate upregulated Fut2 expression via activation of the MEK4-JNK pathway, improved intestinal barrier integrity, and protected neonatal mice from NEC. We found that exogenous butyrate could improve intestinal barrier integrity and protect against NEC in neonatal mice. Our data showed that exogenous butyrate supplementation upregulated Fut2 expression by activating the MEK4-JNK pathway. Our study provides novel insights into the pathogenesis of NEC, thereby laying an experimental foundation for future clinical research on the use of butyrate in NEC treatment.