Inflammation modulates fibronectin isoform expression in colonic lamina propria fibroblasts (CLPF).

BACKGROUND: Migration of colonic lamina propria fibroblasts (CLPF) plays an important role during mucosal wound healing as well as fibrosis and fistula formation in Crohn's disease (CD). Recently, we showed that the migratory potential of CD-CLPF was significantly reduced compared to control CLPF. Fistula-derived CD-CLPF migrated less and fibrosis-CLPF more than CLPF from inflamed CD mucosa. These changes in migratory behavior were associated with changes in production of the migration-inducing fibronectin (FN) isoforms ED-A and ED-B. A permanent reduction of the migratory potential of CLPF was mediated by IFN-gamma and tumor necrosis factor (TNF) modulate FN isofom expression in CLPF and thereby might regulate CLPF migration.
MATERIALS AND METHODS: Control CLPF were incubated for 72 h with IFN-gamma, TNF, IFN-gamma plus TNF, or TGF-beta1. Messenger RNA (mRNA) was isolated and expression of FN and isoforms ED-A and ED-B was quantified by real-time polymerase chain reaction. FN, ED-A, and ED-B were investigated by Western blotting. FN receptor integrin alpha5beta1 was analyzed by FACS.
RESULTS: No difference was found for the surface display of integrin alpha5beta1 between stimulated and non-stimulated cells. In TGF-beta1 incubated CLPF mRNA amount of FN and isoforms ED-A and ED-B was slightly increased. IFN-gamma only decreased FN in CLPF, TNF significantly reduced FN-mRNA by 40%, FN ED-A mRNA by 25%, and ED-B mRNA by 50%. The TNF-mediated mRNA downregulation resulted in a decreased protein amount as revealed by Western blotting.
CONCLUSION: Cytokines such as IFN-gamma, TNF, and TGF-beta1 modulate the production of fibronectin isoforms. Our data indicate that inflammation-induced modulation of FN-isoform production is involved in the alterations of migratory potential of CLPF isolated from CD mucosa.