Mucosal protection by hypoxia-inducible factor prolyl hydroxylase inhibition

Background & Aims: A number of recent studies have implicated tissue hypoxia in both acute and chronic inflammatory diseases, particularly as they relate to mucosal surfaces lined by epithelial cells. In this context, a protective role for the transcriptional regulator hypoxia-inducible factor (HIF) was shown through conditional deletion of epithelial HIF-1 alpha in a murine model of colitis. Here, we hypothesized that pharmacologic activation of HIF would similarly provide a protective adaptation to murine colitic disease. Methods: For these purposes, we used a novel prolyl hydroxylase (PHD) inhibitor (FG-4497) that readily stabilizes HIF-1 alpha and subsequently drives the expression downstream of HIF target genes (eg, erythropoietin). Results: Our results show that the FG-4497-mediated induction of HIF-1 alpha provides an overall beneficial influence on clinical symptoms [weight loss, colon length, tissue tumor necrosis factor-a (TNF alpha)] in murine trinitrobenzene sulfonic acid (TNBS) colitis, most likely because of their barrier protective function and wound healing during severe tissue hypoxia at the site of inflammation. Conclusions: Taken together these findings emphasize the role of epithelial HIF-1 alpha during inflammatory diseases in the colon and may provide the basis for a therapeutic use of PHD inhibitors in inflammatory mucosal disease.