Figure 4. The MCP-1 produced by ARPE-19 cells is biologically active, as measured by the calcium mobilization assay. ARPE-19 cells transfected with an EGFP plasmid (control) or with a DN-NFAT5 plasmid were incubated for 8 h with Iso or Na100. The cell supernatants were then collected and applied to CHO-WTA11 cells expressing CCR2 to measure calcium mobilization. The results were normalized for baseline activity (0%) and the maximal response obtained with 25 µM adenosine triphosphate (100%). The dotted line indicates the calcium mobilization threshold set using CHO-WAT11 cells. The displayed data are the mean ± SEM of four independent experiments and measurements performed in duplicates. Data were analyzed using the one-way analysis of variance and post hoc Sidak’s tests. *p < 0.05, **p < 0.01, ***p < 0.001.