Pdgf And Tgf-Beta Promote Tenascin-C Expression In Subepithelial Myofibroblasts And Contribute To Intestinal Mucosal Protection In Mice

Background and PurposeTenascin-C (TnC) is a multi-domain extracellular matrix glycoprotein that is expressed at a high level during embryogenesis but is almost absent during normal postnatal life. This multi-domain complex molecule is reported to associate with both pro-inflammatory and anti-inflammatory signalling cascades. In this study, we examined how TnC modulated intestinal inflammation.Experimental ApproachTnC pathophysiology was evaluated in cultures of rat intestinal subepithelial myofibroblasts (ISEMF) and intestinal epithelial cells. Wild-type and TnC(-/-) mice were treated with dextran sodium sulfate (DSS) to induce colitis.Key ResultsDSS-induced colitis in mice markedly increased TnC in the damaged mucosal areas and up-regulated mRNA for TnC, pro-inflammatory cytokines and growth factors (PDGF-B and TGF-1). In addition, 2,4,6-trinitrobenzene sulfonic acid-induced colitis and SAMP1/Yit mice, a model of spontaneous Crohn's disease, also exhibited increased mucosal TnC in colon and ilea respectively. PDGF receptor- (PDGFR) positive ISEMF were the primary TnC-producing cells in colon tissues. Accordingly, ISEMF collected from the rat colon constitutively expressed both TnC and PDGFR. PDGF-BB and TGF-1 up-regulated both TnC mRNA and protein levels in ISEMF. Knock-down of TnC gene increased susceptibility to DSS-induced colitis, compared with TnC(+/+) littermates. TnC(-/-) mice showed marked abrasion of intestinal mucosal barrier and increased inflammatory scores. Moreover, TnC accelerated both trans-well migration and wound healing in epithelial cells.Conclusions and ImplicationsThe pharmacological profiles of PDGF-BB and TGF- in colitis tissues and ISEMF suggest that increased TnC production during inflammation contributed to epithelial cell migration, remodelling and protection of intestinal barriers.