Rhamnogalacturonan promotes intestinal mucosal repair through increased cell migration

Mucosal healing is the primary goal for inflammatory bowel disease (IBD) treatment. We previously showed the direct beneficial effects of rhamnogalacturonan (RGal) on intestinal epithelial barrier function. Here, we aimed to evaluate the effect of RGal in intestinal epithelial wound healing. Confluent cancer cell lines and colonoid monolayers were wounded, treated with RGal for 48 h, and assessed using a live cell imaging system. Proliferation and apoptosis of cells were evaluated using 5-ethynyl-2'-deoxyuridine (EdU) and TUNEL assays, respectively. Inhibitors were used to determine the receptor and signaling pathways involved. Female and male mice with DSS-induced colitis were treated orally with RGal for 7 days during the recovery phase. RGal enhanced wound healing in Caco-2, T84, and primary cells by increasing cell migration. Inhibition of pretranscriptional signaling pathways FAK, Src, PI3K, Rho family, and JNK reversed the RGal-induced wound healing. RNAseq data from Caco-2 and primary cells treated with RGal showed the upregulation of the NF-κB pathway at 12 h. Actinomycin D, Bay 11-7082 or JSH-23, and NS-398 treatment significantly reversed the effect of RGal on wound healing, confirming that the response was also transcriptionally dependent and involved NF-κB signaling and downstream COX-2 protein activity. RGal treatment of male mice enhanced recovery from DSS colitis. RGal promoted wound healing in cancer and primary cells by increasing cell migration and accelerated epithelial mucosal healing in male mice. Our findings show a novel mechanism of action of RGal in wound healing that could help in mucosal healing and the resolution of intestinal inflammation.NEW & NOTEWORTHY RGal increases wound healing in colon cancer cell lines and primary cells through increased cell migration and participation of important pretranscriptional signaling pathways and the transcription factor NF-κB. In addition, RGal also accelerates intestinal mucosal healing of male mice with DSS-induced colitis.