KERATINOCYTE GROWTH-FACTOR STIMULATION OF GELATINASE (MATRIX METALLOPROTEINASE-9) AND PLASMINOGEN-ACTIVATOR IN HISTIOTYPIC EPITHELIAL-CELL CULTURE

The purpose of this investigation was to examine the role that keratinocyte growth factor (KGF) plays in the control of matrix-degrading protease activity in epithelial cells. The culture conditions had a significant effect on cellular responses to the growth factor. In histiotypic culture on porous-polycarbonate membranes, porcine periodontal ligament epithelial cells responded to KGF with increased 92-kDa gelatinase (matrix metalloproteinase [MMP]-9) activity. No such response was observed in cells maintained on plastic plates. Epidermal growth factor and platelet-derived growth factor also increased MMP-9 activity in the histiotypic cultures of epithelial cells. Addition of heparin with KGF produced a further increase in MMP-9 activity, with heparin alone having no effect. Precoating of polycarbonate membranes with matrix components showed that fibronectin and an engineered poly-RGD molecule substrate were required for KGF plus heparin to increase MMP-9 activity. Precoating plastic culture plates with the same proteins did not generate the same response. Concomitant with gelatinase activity, KGF also increased urokinase-type plasminogen activator in the epithelial cells. Thus, KGF appears to be an important regulator of protease secretion in epithelial cells.