Figure 3. High osmolality-induced expression of transcription factors in RPE cells. A: Chemical hypoxia (induced by the addition of 150 µM CoCl₂) and high salt (+ 100 mM NaCl) do not additively increase the expression of the VEGF gene. B: High osmolality, induced by the addition of 100 mM salt (NaCl) or 100 mM sucrose to the culture medium, induces gene expression of hypoxia-inducible factor-1 alpha (HIF-1α). Low osmolality (Low Osm; 60% osmolality) has no effect. C: High osmolality increases, and low osmolality decreases, the gene expression of nuclear factor of activated T cell 5 (NFAT5). Hypoxia (1% O₂) has no effect. Inset: The NFAT5 protein level in RPE cells determined with western blot analysis. High salt increases and low osmolality decreases the cellular NFAT5 protein level. Hypoxia (+ 150 µM CoCl₂) has no effect. *p<0.05 vs. control. Modified after Hollborn et al. [57].