N-cadherin is overexpressed in Crohn's stricture fibroblasts and promotes intestinal fibroblast migration

Abstract

Background: Intestinal fibroblasts mediate stricture formation in Crohn's disease (CD). Transforming growth factor-β 1 (TGF- β 1) is important in fibroblast activation, while cell attachment and migration is regulated by the adhesion molecule N-cadherin. The aim of this study was to investigate the expression and function of N-cadherin in intestinal fibroblasts in patients with fibrostenosing CD. Methods: Intestinal fibroblasts were cultured from seromuscular biopsies from patients undergoing resection for terminal ileal fibrostenosing CD (n = 14) or controls patients (n = 8). N-cadherin expression was assessed using Western blot and quantitative reverse-transcription polymerase chain reaction (qRT-PCR). Fibroblasts were stimulated with TGF-β 1 and selective pathway inhibitors Y27632, PD98050, and LY294002 were used to examine the Rho/ROCK, ERK-1/2, and Akt signaling pathways, respectively. Cell migration was assessed using a scratch wound assay. N-cadherin was selectively overexpressed using a plasmid. Results: Fibroblasts from fibrostenosing CD express increased constitutive N-cadherin mRNA and protein and exhibit enhanced basal cell migration relative to those from directly adjacent normal bowel. Control fibroblasts treated with TGF-β 1 induced N-cadherin in a dose-dependent manner which was inhibited by Rho/ROCK and Akt pathway modulation. Control fibroblasts exhibited enhanced cell migration in response to treatment with TGF-β 1 or transfection with an N-cadherin plasmid. Conclusions: Fibroblasts from strictures in CD express increased constitutive N-cadherin and exhibit enhanced basal cell migration. TGF-β 1 is a potent inducer of N-cadherin in intestinal fibroblasts resulting in enhanced cell migration. The TGF-β 1-mediated induction of N-cadherin may potentiate Crohn's stricture formation. (Inflamm Bowel Dis 2011;) Copyright © 2011 Crohn's & Colitis Foundation of America, Inc.