The Protective Effect of Hispidin against Hydrogen Peroxide-Induced Oxidative Stress in ARPE-19 Cells via Nrf2 Signaling Pathway

Abstract

Hispidin, a polyphenol compound isolated from Phellinus linteus, has been reported to possess antioxidant activities. In this study, we aimed to investigate the mechanisms underlying the protective effect of hispidin against hydrogen peroxide (H2O2)-induced oxidative stress on Adult Retinal Pigment Epithelial cell line-19 (ARPE-19) cells. Hispidin was not cytotoxic to ARPE-19 cells at concentrations of less than 50 μM. The levels of intracellular reactive oxygen species (ROS) were analyzed by dichlorofluorescin diacetate (DCFDA) staining. Hispidin significantly restored H2O2-induced cell death and reduced the levels of intracellular ROS. The expression levels of antioxidant enzymes, such as NAD(P)H:Quinine oxidoreductase-1 (NQO-1), heme oxygenase-1 (HO-1), glutamate-cysteine ligase catalytic subunit (GCLC), and glutamate-cysteine ligase modifier subunit (GCLM) were examined using real-time PCR and Western blotting. Our results showed that hispidin markedly enhanced the expression of nuclear factor erythroid 2-related factor 2 (Nrf2), HO-1, NQO-1, GCLM, and GCLC in a dose-dependent manner. Furthermore, knockdown experiments revealed that transfection with Nrf2 siRNA successfully suppresses the hispidin activated Nrf2 signaling in ARPE-19 cells. Moreover, activation of the c-Jun N-terminal kinase (JNK) pathway is involved in mediating the protective effects of hispidin on the ARPE-19 cells. Thus, the present study demonstrated that hispidin provides protection against H2O2-induced damage in ARPE-19 cells via activation of Nrf2 signaling and up-regulation of its downstream targets, including Phase II enzymes, which might be associated with the activation of the JNK pathway.

Antioxidative Effects of Chrysoeriol via Activation of the Nrf2 Signaling Pathway and Modulation of Mitochondrial Function

“…These findings indicate that chrysoeriol may possess the ability to scavenge oxygen free radicals, thereby indirectly combating oxidative stress. Numerous studies have reported that Nrf2 activation is a major regulator of several antioxidant and detoxification genes in RPE cells, including downstream targets of Nrf2 [ 39 , 40 , 41 , 42 , 43 , 44 ]. Our study suggests that chrysoeriol activates Nrf2 and increases HO-1 and NQO-1 activity in H 2 O 2 -exposed cells, as demonstrated by RT-qPCR and Western blot analyses.…”

Punicalagin Protects Human Retinal Pigment Epithelium Cells from Ultraviolet Radiation-Induced Oxidative Damage by Activating Nrf2/HO-1 Signaling Pathway and Reducing Apoptosis

“…In addition, our evidence fully introduces PUN among antioxidant natural substances able to protect RPE from oxidative stress. In this regard, there is a wide research line that describes compounds of natural origin capable of protecting RPE, via Nrf2 activation, against various oxidative stimuli (mainly H 2 O 2 ) [ 29 , 30 , 31 ]. However, the fact that, in our experimental paradigm, PUN protects epithelium against UV radiation (the main natural exogenous stressor for RPE) makes it particularly noteworthy, compared to other compounds.…”

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

“…On further investigating the possible mechanism associated with the protective ability of TPP-Niacin, it has appeared that the HO-1 and NQO-1 of downstream target genes of NRF2 signalling play major roles in the prevention of the cells from oxidative damage [39,40]. Recently, many studies have reported that the activation of NRF2/HO-1 signalling is required for the alleviation of oxidative damage to RPE cells [40][41][42][43][44][45]. In this study, it was speculated that the anti-oxidative effects of TPP-Niacin might be combined with PGC-1α and NRF2 signalling.…”