UBE2W Improves the Experimental Colitis by Inhibiting the NF-κB Signaling Pathway.

Abstract

The NF-κB signaling cascade regulates immune response and is often dysregulated in tumor development. UBE2W is a novel type I ubiquitin-conjugating enzyme (E2) whose biological function is still unclear. This study was designed to investigate whether UBE2W regulates NF-κB signaling pathway and is involved in the progression of experimental colitis. At the cellular level, the effect of UBE2W on NF-κB transcriptional activity was measured using a dual-luciferase reporter assay. The influence of UBE2W on NF-κB pathway activation and the entry of p65 into the nucleus were determined by Western blot and immunofluorescence analyses, respectively. Moreover, the colitis model was established by administering 2.5% dextran sulfate sodium (DSS)/water to UBE2W overexpression, UBE2W-knockdown and control mice. Body weight, stool consistency, colon length and clinical severity were examined. Expression of pro-inflammatory cytokines and phosphorylation of p65 and IκB in the colon tissue were measured by qRT-PCR and Western blot, respectively. UBE2W inhibited TNFα-induced NF-κB transcription activity, attenuated IκB and p65 phosphorylation, downregulated TNFα and IL-8 expression and blocked the entry of p65 into the nucleus. In the DSS-induced colitis model, UBE2W-knockdown mice had increased weight loss, more serious diarrhea and mucosal injures compared with the control mice. Moreover, phosphorylation of IκB and p65 and the expression of pro-inflammatory mediators such as TNFα, IL-6 were significantly increased in UBE2W knockdown mice. However, these changes were completely reversed in UBE2W overexpression mice. The overexpression of UBE2W ameliorates the severity of DSS-induced colitis, which may be mediated by inhibiting the expression of pro-inflammatory mediators and activation of the NF-κB signaling pathway. These findings provide evidence that UBE2W might have potential therapeutic implications in IBD.