ADULT HUMAN COLONIC SUBEPITHELIAL MYOFIBROBLASTS EXPRESS EXTRACELLULAR-MATRIX PROTEINS AND CYCLOOXYGENASE-1 AND CYCLOOXYGENASE-2

Interactions between epithelial cells and subepithelial myofibroblasts are increasingly recognized as important in the regulation of epithel ial cell function. We have established primary cultures of subepitheli al myofibroblasts from adult human colonic mucosal samples denuded of epithelial cells and maintained in culture. During culture of mucosal tissue, subepithelial myofibroblasts migrated out via basement membran e pores before establishment in culture. Despite prolonged culture and passage, the myofibroblasts maintained their phenotype, as demonstrat ed by expression of alpha-smooth muscle actin and vimentin. The cells expressed transcripts and protein for cyclooxygenase (COX)-1 and -2 en zymes, and their release of prostaglandin E-2 (PGE(2)) was inhibited b y selective COX-1 and -2 inhibitors. The myofibroblasts also expressed the extracellular matrix (ECM) proteins collagen type IV, laminin-bet a(1) and -gamma(1), and fibronectin. Adult human colonic subepithelial myofibroblasts may influence epithelial cell function via products of COX-1 and -2 enzymes, such as PGE(2) and secreted ECM proteins.