Abstract
Abstract: :
Purpose: We previously showed that elevated glucose inhibits HGF-stimulated hRPE cell proliferation. Others have shown that bFGF induces HGF synthesis in osteoblasts. We therefore investigated the effect of bFGF in the absence and presence of elevated glucose on HGF and its receptor (c-met) synthesis in cultured hRPE cells. Methods: Cultured hRPE cells were grown to confluence and labeled with 14C-methionine in the presence and absence of elevated glucose (5-20 mM) and bFGF (0-100 ng/ml). 14C-methionine-labeled intracellular HGF and c-met were immunoprecipitated by HGF and c-met specific antibodies and counted on a scintillation counter. Immunoprecipitated 14C-methionine-HGF was also analyzed by SDS-PAGE analysis. Data were analyzed by Student 't' test and Wilcoxon Signed Rank test. p<0.05 was considered significantly different. Results: bFGF stimulates 14C-methionine-HGF and 14C-methionine-c-met synthesis in hRPE cells in a dose dependent manner. Addition of glucose (20 mM) to bFGF (100 ng/ml) significantly inhibited intracellular 14C-methionine-HGF synthesis when compared with bFGF alone (1933±428 vs. 317±341,CPM±SEM, p<0.013,n=6). Further, addition of glucose (20 mM) to bFGF (100 ng/ml) significantly inhibited intracellular 14C-methionine-c-met synthesis when compared with bFGF alone (2321±996 vs.1833±786,CPM±SEM, p<0.023, n=6). SDS-Page analysis also showed inhibition of bFGF stimulated 14C-methionine-HGF synthesis in presence of elevated glucose. Conclusion: bFGF stimulates HGF and c-met synthesis in cultured hRPE cells and elevated glucose inhibits this response. These results suggest that interaction of bFGF, HGF and its receptor, c-met, may play a role in diabetes-related eye diseases.
Keywords: 423 growth factors/growth factor receptors • 388 diabetic retinopathy