Figure 6. Keap1 depletion mimics obacunone-induced RPE cytoprotection against UVR. Stable ARPE-19 cells with the CRISPR/Cas9-Keap1-KO construct (“ko-Keap1”) or the empty vector (“Cas9-C”) were treated with or without obacunone (25 μM), cells were further cultured for 6h, expression of listed genes was shown (A, B), with ARE activity tested (C). Alternatively, cells were pretreated with obacunone (25 μM) for 1h, followed by UVR for another 48h, cell viability and death were tested by CCK-8 (D) and medium LDH release (E) assays, respectively. Expression of listed proteins was quantified, normalized to the loading control, and expressed as mean ± SD (n=5) (A). Data were presented as mean ± SD (n=5). #p < 0.05 vs. “Cas9-C” cells. Experiments were repeated three times, with similar results obtained.