Figure 1. PDGF-mediated SOCS3 induction in human corneal fibroblasts involves JAK2-STAT3 pathway. Human corneal fibroblasts were exposed to a mixture of PDGF (AA, AB, and BB) at a final concentration of 20 ng/ml with or without JAK2-STAT3 inhibitor, AG-490 (final concentration of 100 μM) for 1 h or 8 h. SOCS3 transcript levels were quantified by real-time PCR, and protein levels were determined by immunoprecipitation and immunoblotting using the SOCS3 polyclonal antibody. A: The fold change in SOCS3 transcript levels compared to untreated control is shown as mean ±SEM. The PDGF treatment increases SOCS3 mRNA levels by threefold at 1 h and 4.5 fold at 8 h, and AG-490 treatment inhibits PDGF-induced SOCS3 mRNA levels significantly. The asterisk indicates a p<0.05 versus control and the double asterisk indicates a p<0.05 versus PDGF. B: SOCS3 protein levels in PDGF-treated, BSA-treated or untreated cells showing 1.5 to 2.5 fold increase in SOCS3 protein expression by PDGF treatment. Pre-immune serum was used as a negative control for immunoprecipitation.