Genipin protects against H2O2-induced oxidative damage in�retinal pigment epithelial cells by promoting Nrf2 signaling

Abstract

Oxidative stress serves a vital function in the pathogenesis of age-related macular degeneration (AMD); genipin (GP) possesses antioxidative properties. The present study aimed to investigate the effects of GP on retinal pigment epithelial (RPE) cells induced by H2O2 and the underlying mechanism. ARPE-19 cells were subjected to H2O2 treatment to induce oxidative damage. Cell viability was determined via an MTT assay. Reactive oxygen species (ROS) levels and cell apoptosis were detected by flow cytometry. Nuclear factor-erythroid 2-related factor-2 (Nrf2) signaling-associated and the expression of apoptosis-associated factors were measured using reverse transcription-quantitative polymerase chain reaction assay and western blotting. The results revealed that 200 µM H2O2 and 30 µM GP were determined to be the optimal concentrations for subsequent experimentation. GP reversed the inhibitory effects of H2O2 by promoting cell viability, attenuating ROS accumulation and cell apoptosis, and increased the expression of Nrf2, heme oxygenase-1 (HO-1) and NAD(P)H: Quinine oxidoreductase 1 (NQO1); Nrf2 silencing inhibited HO-1 and NQO1 expression. In addition, Nrf2 silencing enhanced the effects of H2O2 by promoting ROS production and cell apoptosis. Compared with H2O2, Nrf2 silencing further decreased the expression levels of B-cell lymphoma-2 (Bcl-2), but increased that of Bcl-2-associated X protein and cleaved-caspase-3. The results of the present study revealed that Nrf2 silencing attenuated the protective effects of GP on H2O2-induced injury in ARPE-19 cells by promoting apoptosis and oxidation. Collectively, GP attenuated oxidative damage induced by H2O2 in ARPE-19 cells. Furthermore, the molecular mechanism may be associated with the Nrf2 signaling pathway. The findings of the present study nay provide insight into a potential therapeutic agent for the treatment of AMD.

Nanoceria Particles Are an Eligible Candidate to Prevent Age-Related Macular Degeneration by Inhibiting Retinal Pigment Epithelium Cell Death and Autophagy Alterations

“…Cells 2020, 9, x 6 of 17 violet staining. Our results showed that hydrogen peroxide produced a progressive cytotoxic effect in the ARPE-19 cells with the increase of H2O2 concentration, as highlighted in other studies [41,42]. The cytotoxic effect was significant at 600 µM with 35% toxicity and reaching a maximum effect at 1000 µM with a toxicity of about 60% (Supplementary Materials, Figure S1).…”

“…In order to evaluate the protective effects of cerium oxide nanoparticles against H 2 O 2 -induced cytotoxicity, ARPE-19 cells were treated with increasing concentrations of H 2 O 2 (200 µM, 400 µM, 600 µM, 800 µM, and 1000 µM) for 24 h and the degree of cell proliferation was evaluated by Crystal violet staining. Our results showed that hydrogen peroxide produced a progressive cytotoxic effect in the ARPE-19 cells with the increase of H 2 O 2 concentration, as highlighted in other studies [41,42]. The cytotoxic effect was significant at 600 µM with 35% toxicity and reaching a maximum effect at 1000 µM with a toxicity of about 60% (Supplementary Materials, Figure S1).…”

Eye-Light on Age-Related Macular Degeneration: Targeting Nrf2-Pathway as a Novel Therapeutic Strategy for Retinal Pigment Epithelium

“…In particular, in wild type and Nrf2-deficient ARPE-19 cells, we studied the effects of the following pro-oxidant AMD-related noxae: H 2 O 2 , 4-hydroxynonenal (4-HNE), MG132 + Bafilomycin. H 2 O 2 is a strong oxidant leading to an immediate ROS production, widely used in in vitro study on RPE cells (Zhu et al, 2017;Hu et al, 2019;Zhao et al, 2019), that are physiologically subjected to elevated ROS levels due to their high metabolism and functions (Strauss, 2005). 4-HNE is a product of lipid peroxidation accumulating in AMD retina (Ethen et al, 2007); it is pro-oxidant and toxic for RPE (Kaarniranta et al, 2005;Kaemmerer et al, 2007;Chen et al, 2009), but its effects on Nrf2-pathway have been not fully elucidated.…”

Improved Effect of a Mitochondria-Targeted Antioxidant on Hydrogen Peroxide-Induced Oxidative Stress in Human Retinal Pigment Epithelium Cells

“…On further investigating the possible mechanisms associated with the protective ability of TPP-Niacin, it appears that HO-1 and NQO-1, which are downstream targets of NRF2 signaling, play major roles in the prevention of oxidative damage in the cells [39,40]. Recently, many studies have reported that the activation of NRF2/HO-1 signaling is required to alleviate oxidative damages in RPE cells [41,42] [43][44][45][46]. In this study, it was speculated that the antioxidative effects of TPP-Niacin could be combined with PGC-1α and NRF2 signaling.…”