Fibronectin induces protease dependent focal matrix depletion and cell overlap in cultured rheumatoid synoviocytes.

Abstract

To characterize the effect of added fibronectin (Fn) on human rheumatoid synoviocytes (RAS). Early passage cultured RAS were studied by fluorescent imaging microscopy with multiple parameter overlaying and confocal laser scanning microscopy. Added Fn induced a localized decrease in matrix Fn at sites of cell overlap. Similar matrix depletion could be induced by collagen VI, cell binding (120 k) and heparin binding (60 k) fragments of Fn, but not by gelatin binding fragment (45 k). The decrease in matrix Fn was associated with the induction of a transformation-like phenotype of overlapping cell growth. Both phenomena were inhibited by serine protease inhibitors.