High MUC2 Mucin Biosynthesis in Goblet Cells Impedes Restitution and Wound Healing by Elevating Endoplasmic Reticulum Stress and Altered Production of Growth Factors.

Intestinal epithelial cell wound healing involves cell migration, proliferation, and differentiation. Although numerous studies have analyzed the migration of absorptive epithelial cells during wound healing, it remains unclear how goblet cells restitute and how MUC2 mucin production affects this process. In this study, we examined the role of high MUC2 production in goblet cell migration during wound healing and demonstrated that during high MUC2 output, goblet cells migrated slower because of impaired production of wound healing factors and endoplasmic reticulum (ER) stress. Two goblet cell lines, HT29-H and HT29-L, that produced high and low MUC2 mucin, respectively, were used. HT29-L healed wounds faster than HT29-H cells by producing significantly higher amounts of fibroblast growth factor (FGF) 1, FGF2, vascular endothelial growth factor-C, and matrix metallopeptidase 1. Predictably, treatment of HT29-H cells with recombinant FGF2 significantly enhanced migration and wound healing. High MUC2 biosynthesis in HT29-H cells induced ER stress and delayed migration that was abrogated by inhibiting ER stress with tauroursodeoxycholic acid and IL-22. FGF2- and IL-22-induced wound repair was dependent on STAT1 and STAT3 signaling. During wound healing after dextran sulfate sodium-induced colitis, restitution of Math1M1GFP+ goblet cells occurred earlier in the proximal colon, followed by the middle and then distal colon, where ulceration was severe. We conclude that high MUC2 output during colitis impairs goblet cell migration and wound healing by reducing production of growth factors critical in wound repair.