Interferon-γ Inhibits T84 Epithelial Cell Migration by Redirecting Transcytosis of β1 Integrin from the Migrating Leading Edge

Abstract

Intestinal inflammation is associated with epithelial damage and formation of mucosal wounds. Epithelial cells migration is required for wound closure. In inflammatory status, migrating epithelial cells are exposed to proinflammatory cytokines such as IFN-γ. However, influence of such cytokines on intestinal epithelial wound closure remains unknown. The present study was designed to investigate the effect of IFN-γ on migration of model T84 intestinal epithelial cells and recovery of epithelial wounds. IFN-γ significantly inhibited rate of T84 cell migration and closure of epithelial wounds. This effect was accompanied by the formation of large aberrant lamellipodia at the leading edge as well as significant decrease in the number of β1 integrin containing focal adhesions. IFN-γ exposure increased endocytosis of β1 integrin and shifted its accumulation from early/recycling endosomes at the leading edge to a yet unidentified compartment at the cell base. This redirection in β1 integrin transcytosis was inhibited by depolymerization of microtubules with nocodazole and was unaffected by stabilization of microtubules with docetaxel. These results suggest that IFN-γ attenuates epithelial wound closure by microtubule-dependent redirection of β1 integrin transcytosis from the leading edge of migrating cells thereby inhibiting adequate turnover of focal adhesion complexes and cell migration.

Interferon-γ inhibits enterocyte migration by reversibly displacing connexin43 from lipid rafts

“…As is shown in Fig. 1G, the rate of enterocyte migration was significantly reduced upon exposure to IFN, consistent with our previous findings (32) and those of others (52). Importantly, inhibition of gap junctions with oleamide or upon infection of IEC-6 cells with adenoviruses that express dominant negative but not wild-type Cx43 significantly reduced the rate of enterocyte migration (Fig.…”

“…As shown in Fig. 5, A-D and I, IFN inhibited the migration of IEC-6 cells into a scraped wound compared with untreated cells, a finding consistent with recent findings from our group (32) and supported by the work of others (52). Strikingly, the pretreatment of enterocytes with PMA, which restores Cx43 to lipid rafts after IFN treatment (see Fig.…”

“…We readily acknowledge that IFN may affect other pathways that impair migration. For instance, IFN has been shown to prevent wound healing by causing endocytosis of ␤1-integrin focal adhesions (52) and to disrupt tight junctions (34) in vitro. These findings therefore raise the possibility that the disruption of gap junctions by IFN between enterocytes may be a secondary consequence to disruption of other junctional/cell adhesion complexes.…”

14-3-3 Proteins regulate Akt Thr308 phosphorylation in intestinal epithelial cells

“…Cytokines such as IFNγ and TNFα are critical mediators that contribute to the epithelial barrier breakdown by disassembling tight junctions, reducing the rate of intestinal epithelial cell migration, decreasing IEC proliferation and increasing cell death. 1,2,40,41 Cytokine mediators regulate biological processes by altering several signaling pathways including Akt, NOs and JAK/STAT. 1,42,43 However, the mechanisms underlying those processes are incompletely understood.…”

Curcumin inhibits interferon-γ signaling in colonic epithelial cells

“…One of the most prominent proinflammatory cytokines with profound effects on epithelial cells is IFN-␥. Elevated IFN-␥ disrupts the epithelial barrier function by inducing tight junction internalization (7) and size-selective increase in permeability (45), prevents epithelial cell migration (27), impairs wound healing by causing endocytosis of ␤ 1 -integrin containing focal adhesions and by preventing interenterocyte gap junction communication via connexin 43 (28,43). All of these are thought to contribute to the pathogenesis of inflammatory bowel diseases (10).…”