Fig. 6.

Effect of JNK inhibition or Nrf2 activation and knockdown on LPS-stimulated ARPE-19 cells. a/d A 1 h pretreatment with the JNK inhibitor SP600215 (SP, 10 µM) increased IL-6 (a) and slightly decreased IL-8 (d) secretion in 10 µg/ml LPS (LPS)-stimulated ARPE-19 cells. b/e A 1 h pretreatment with the Nrf2 activator sulforaphane (SUL, 20 µM) significantly decreased the secretion of IL-6 (b) or IL-8 (e) from LPS-treated RPE cells with or without phloretin (PHL). c/f Nrf2 knockdown by siRNA transfection before exposure to phloretin (PHL) and LPS increased IL-6 (c) or IL-8 (f) secretion when compared to phloretin and LPS stimulation alone, but only changes for IL-8 were statistically significantly different to the effect of scrambled control siRNA. Results are combined from three or four independent experiments with three or four parallel samples per experiment and are represented as mean ± SEM. ns not statistically significant, *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001, Mann–Whitney U-test