Knockdown of ghrelin-O-acyltransferase attenuates colitis through the modulation of inflammatory factors and tight junction proteins in the intestinal epithelium.

Abstract

Ghrelin-O-acyltransferase (GOAT) is a membrane-bound enzyme that attaches eight-carbon octanoate to a serine residue in ghrelin and thereby acylates inactive ghrelin to produce active ghrelin. In this study, we investigated the function of GOAT in the intestinal mucosal barrier. The intestinal mucosal barrier prevents harmful substances such as bacteria and endotoxin from entering the other tissues, organs, and blood circulation through the intestinal mucosa. Here, we established 5% dextran sodium sulfate (DSS)-induced colitis in mice and found that the body weight and colon weight were significantly decreased in these mice. Furthermore, increased inflammation and apoptosis were observed in the tissues of DSS-induced colitis mice, with increased expression of tumor necrosis factor-α, interleukin-6, phosphorylation of nuclear factor kappa B-p65 (p-NF-κB-p65), and cleaved caspase-3, and decreased expression of tight junction (TJ) proteins such as zonula occluden-1 and occludin. The knockdown of GOAT significantly attenuated colitis-induced inflammation responses and apoptosis, while GOAT overexpression significantly enhanced the induction of colitis. These results suggest that knockdown of GOAT may attenuate colitis-induced inflammation, ulcers, and fecal occult blood by decreasing the intestinal mucosal permeability via the modulation of inflammatory factors and TJ proteins.