Microbiota metabolites SCFA stimulate epithelial migration to promote wound healing through MFGE8 and PAK1

Abstract

Abstract How microbiota regulate intestinal homeostasis is still not completely understood. Emerging evidence indicates that gut microbiota metabolites play crucial roles in maintenance of intestinal homeostasis and regulation of Inflammatory Bowel Disease (IBD). Many patients with IBD are deficient in the microbial metabolites of dietary fibers, short chain fatty acids (SCFAs). To date, the evidence for use of SCFAs as a treatment for IBD has been inconsistent, highlighting the need for further investigation. In this study, we demonstrate that SCFAs promote intestinal epithelial cell (IEC) wound healing. Treatment of mouse and human IEC in vitro with the SCFAs acetate, propionate, and butyrate enhanced wound closure by promoting cell migration, which was independent of cell proliferation. Further analysis of random cell migration revealed that SCFAs increased cell speed, cell persistence, and consequently mean squared displacement. To investigate the mechanism of enhanced migration, we performed microarray of mouse-derived enteroids, which identified p21 activated kinase 1 (PAK1) and milk fat globule-EGF factor 8 (MFGE8), two genes implicated in tissue repair and motility, to be highly upregulated. We confirmed upregulation of MFGE8 and PAK1 via qRT-PCR and western blot. Inhibition of PAK1 and CRISPR knockout of MFGE8 abrogated the effects of SCFAs on migration. Lastly, the above effects were dependent upon SCFAs inhibition of histone deacetylases (HDAC), as treatment of IECs with the HDAC inhibitor, trichostatin A, fully recapitulated the effects of SCFAs on migration and expression of MFGE8 and PAK1. These findings elucidate a pathway in which SCFAs inhibition of histone deacetylases may enhance wound healing in IBD.