EFFECTS OF KGF AND TGF-ß ON HYALURONAN SYNTHESIS AND DISTRIBUTION IN EXTRA-, PERI-, AND INTRACELLULAR COMPARTMENTS OF EPIDERMAL KERATINOCYTES

ABSTRACT The aim of this study was to examine the effects of KGF and TGF-β on HA synthesis and proliferation of rat epidermal keratinocytes. KGF stimulated proliferation at small doses (1 and 10 ng/ml). TGF-β inhibited keratinocyte proliferation at 10 ng/ml. Both growth factors increased the migration of the cells. HA localization was studied with a histochemical staining assay using biotinylated aggrecan G1 domain link-protein complex. In a part of the samples extracellular HA was enzymatically digested prior to permeabilization of the membranes to specifically examine intracellular HA. A five to sixfold increase of intracellular HA staining intensity as compared to control was observed with both growth factors at 24 hours. A twofold increase in pericellular HA was also found with KGF, but no marked effect was seen with TGF-β. Metabolic incorporation of [ 3 H] glucosamine and 35 SO 4 into labelled hyaluronan and chondroitin disaccharides from medium, trypsinate and cell samples revealed a sixfold increase of intracellular HA with KGF at 100 ng/ml. A twofold increase of HA in medium samples was also seen with KGF, but it had no effect on trypsinate samples. TGF-β at 10 ng/ml had no significant effect on extracellular HA, but induced a twofold increase of intra- and pericellular HA.