Phenotypic characterization of an intestinal subepithelial myofibroblast cell line.

Subepithelial myofibroblasts are located at the interface between the epithelium and lamina propria in most mucosal tissues. Their biological functions are largely unknown because a long-term cell culture model for these cells has not been available. In this report, we define the phenotypic properties of a human colonic cell line (18Co) that exhibits most of the known characteristics of intestinal subepithelial myofibroblasts in situ. These characteristics include 1) a cell shape that can be reversibly interconverted between a flattened discoid and stellate morphology, 2) intracellular organelles reminiscent of myofibroblasts and smooth muscle cells in situ, 3) expression of alpha-smooth muscle actin, 4) plasma membrane receptors for endothelins and natriuretic peptides, and 5) regulation of epithelial sensitivity to calcium-dependent secretagogues by paracrine secretion of prostaglandins. 18Co cells provide an exploitable model to begin defining the physiological and pathophysiological functions of intestinal subepithelial myofibroblasts at the molecular level.