EXTRACELLULAR-MATRIX PROTEINS MODULATE HUMAN PERITONEAL MESOTHELIAL CELL BEHAVIOR

Human peritoneal mesothelial cells lie on a basement membrane-like mat erial consisting of fibronectin (FN), type I collagen (CI), type III c ollagen (CIII) and laminin (LA). To understand how these extracellular matrix (ECM) proteins affect mesothelial cell behavior, we investigat ed their effect on the adhesion and proliferation of mesothelial cells . A modified methyltetrazolium dye method was used to assess cell numb er. The results showed that FN, CI, CIII and LA, all increased adhesio n of mesothelial cells. The adhesive effect was blocked dose-dependent ly by a synthetic Arg-Gly-Asp-containing (RGD) peptide. When coated as a substratum (immobilized form), FN, CI, CIII and LA, all enhanced se rum-stimulated and epidermal-growth-factor-stimulated cellular prolife ration as compared with bovine-serum-albumin-blocked plastic surfaces. When added in a soluble form, all matrix proteins except FN inhibited serum-stimulated and epidermal-growth-factor-stimulated cellular prol iferation at high concentrations (CI and CIII: 1-10 mu g/ml, LA: 3-10 mu g/ml). We conclude that peritoneal mesothelial cells possess an RGD -sensitive receptor and that the ECM can modulate adhesion and prolife ration of peritoneal mesothelial cells. The growth-modulating effect d epends on the form and concentration of the ECM proteins.