The novel Nrf2-interacting factor KAP1 regulates susceptibility to oxidative stress by promoting the Nrf2-mediated cytoprotective response

The transcription factor Nrf2 (nuclear factor-erythroid 2-related factor 2) co-ordinately regulates ARE (antioxidant-response element)-mediated induction of cytoprotective genes in response to electrophiles and oxidative stress; however, the molecular mechanism controlling Nrf2-dependent gene expression is not fully understood. To identify factors that regulate Nrf2-dependent transcription, we searched for proteins that interact with the Nrf2-NT (N-terminal Nrf2 transactivation domain) by affinity purification from HeLa nuclear extracts. In the present study, we identified KAP1 [KRAB (Krüppel-associated box)-associated protein 1] as a novel Nrf2-NT-interacting protein. Pull-down analysis confirmed the interaction between KAP1 and Nrf2 in cultured cells and demonstrated that the N-terminal region of KAP1 binds to Nrf2-NT in vitro. Reporter assays showed that KAP1 facilitates Nrf2 transactivation activity in a dose-dependent manner. Furthermore, the induction of the Nrf2-dependent expression of HO-1 (haem oxygenase-1) and NQO1 [NAD(P)H quinone oxidoreductase 1] by DEM (diethyl maleate) was attenuated by KAP1 knockdown in NIH 3T3 fibroblasts. This finding established that KAP1 acts as a positive regulator of Nrf2. Although Nrf2 nuclear accumulation was unaffected by KAP1 knockdown, the ability of Nrf2 to bind to the regulatory region of HO-1 and NQO1 was reduced. Moreover, KAP1 knockdown enhanced the sensitivity of NIH 3T3 cells to tert-butylhydroquinone, H2O2 and diamide. These results support our contention that KAP1 participates in the oxidative stress response by maximizing Nrf2-dependent transcription.

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7β-(3-Ethyl-cis-crotonoyloxy)-1α-(2-methylbutyryloxy)-3,14-dehydro-Z Notonipetranone Attenuates Neuropathic Pain by Suppressing Oxidative Stress, Inflammatory and Pro-Apoptotic Protein Expressions

Molecules ◽

10.3390/molecules26010181 ◽

2021 ◽

Vol 26 (1) ◽

pp. 181

Author(s):

Amna Khan ◽

Adnan Khan ◽

Sidra Khalid ◽

Bushra Shal ◽

Eunwoo Kang ◽

...

Keyword(s):

Oxidative Stress ◽

Neuropathic Pain ◽

Interleukin 1 ◽

Related Factor ◽

Dependent Manner ◽

Glutathione S Transferase ◽

Quinone Oxidoreductase ◽

Apoptotic Protein ◽

Apoptotic Proteins ◽

Apoptosis And Inflammation

7β-(3-Ethyl-cis-crotonoyloxy)-1α-(2-methylbutyryloxy)-3,14-dehydro-Z-notonipetranone (ECN), a sesquiterpenoid obtained from a natural source has proved to be effective in minimizing various side effects associated with opioids and nonsteroidal anti-inflammatory drugs. The current study focused on investigating the effects of ECN on neuropathic pain induced by partial sciatic nerve ligation (PSNL) by mainly focusing on oxidative stress, inflammatory and apoptotic proteins expression in mice. ECN (1 and 10 mg/kg, i.p.), was administered once daily for 11 days, starting from the third day after surgery. ECN post-treatment was found to reduce hyperalgesia and allodynia in a dose-dependent manner. ECN remarkably reversed the histopathological abnormalities associated with oxidative stress, apoptosis and inflammation. Furthermore, ECN prevented the suppression of antioxidants (glutathione, glutathione-S-transferase, catalase, superoxide dismutase, NF-E2-related factor-2 (Nrf2), hemeoxygenase-1 and NAD(P)H: quinone oxidoreductase) by PSNL. Moreover, pro-inflammatory cytokines (tumor necrotic factor-alpha, interleukin 1 beta, interleukin 6, cyclooxygenase-2 and inducible nitric oxide synthase) expression was reduced by ECN administration. Treatment with ECN was successful in reducing the caspase-3 level consistent with the observed modulation of pro-apoptotic proteins. Additionally, ECN showed a protective effect on the lipid content of myelin sheath as evident from FTIR spectroscopy which showed the shift of lipid component bands to higher values. Thus, the anti-neuropathic potential of ECN might be due to the inhibition of oxidative stress, inflammatory mediators and pro-apoptotic proteins.

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ECN from Tussilago Farfara Attenuates Neuropathic Pain by Suppressing Oxidative Stress, Inflammatory and Pro-Apoptotic Proteins Expression in Surgical Model

10.20944/preprints202008.0389.v1 ◽

2020 ◽

Author(s):

Amna Khan ◽

Sidra Khalid ◽

Adnan Khan ◽

Bushra Shal ◽

Eunwoo Kang ◽

...

Keyword(s):

Oxidative Stress ◽

Neuropathic Pain ◽

Interleukin 1 ◽

Related Factor ◽

Dependent Manner ◽

Quinone Oxidoreductase ◽

Distress Symptoms ◽

Tussilago Farfara ◽

Apoptotic Proteins ◽

Apoptosis And Inflammation

7β-(3-ethyl-cis-crotonoyloxy)-1α-(2-methylbutyryloxy)-3,14-dehydro-Z-notonipetranone (ECN), a sesquiterpenoid obtained from a natural origin (Tussilago farfara)has proved to be effective in minimizing various side effects associated with opioids and nonsteroidal anti-inflammatory drugs. The current study focused on investigating the effects of ECN on neuropathic pain induced by partial sciatic nerve ligation (PSNL) by mainly focusing on oxidative stress, inflammatory and apoptotic proteins expression in mice. Neuropathic pain was induced in mice by PSNL surgery performed on day 1 and ECN (1 and 10 mg/kg, i.p.), was administered once daily for 11 days, starting from the third day after surgery. ECN post-treatment was found to reduce hyperalgesia and allodynia in a dose dependent manner. ECN significantly reversed the severity of neuropathic pain by improving distress symptoms and survival rate. ECN remarkably reversed the histopathological abnormalities associated with oxidative stress, apoptosis and inflammation. Furthermore, ECN prevented the suppression of antioxidants (glutathione, glutathione-S-transferase, catalase, superoxide dismutase, NF-E2-related factor-2 (Nrf2), hemeoxygenase-1 and NAD(P)H: quinone oxidoreductase) by PSNL. Moreover, pro-inflammatory cytokines (tumor necrotic factor alpha, interleukin 1 beta, interleukin 6, cyclooxygenase-2 and inducible nitric oxide synthase) expression was reduced by ECN administration. Treatment with ECN was successful in reducing caspase-3 level consistent with the observed modulation of pro-apoptotic proteins. Additionally, ECN showed protective effect on the lipid content of myelin sheath as evident from FTIR spectroscopy which showed the shift of lipid component bands to higher values. Thus, anti-neuropathic potential of ECN might be due to inhibition of oxidative stress, inflammatory mediators and pro-apoptotic proteins.

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Curcumin Ameliorated Oxidative Stress and Inflammation-Related Muscle Disorders in C2C12 Myoblast Cells

Antioxidants ◽

10.3390/antiox10030476 ◽

2021 ◽

Vol 10 (3) ◽

pp. 476

Author(s):

Da-Yeon Lee ◽

Yoon-Seok Chun ◽

Jong-Kyu Kim ◽

Jeong-Ok Lee ◽

Young-Joon Lee ◽

...

Keyword(s):

Oxidative Stress ◽

Radical Scavenging ◽

C2c12 Cells ◽

C2c12 Myoblast ◽

Related Factor ◽

Dependent Manner ◽

Quinone Oxidoreductase ◽

Muscle Disorders ◽

Myoblast Cells ◽

Dose Dependent

The purpose of the current study was to investigate antioxidant and anti-inflammatory effects of spray dry powder containing 40% curcumin (CM-SD) in C2C12 myoblast cells. CM-SD increased DPPH radical scavenging activity in a dose-dependent manner, and up to 30 μg/mL of CM-SD did not express cytotoxicity in C2C12 cells. Exposure to hydrogen peroxide (H2O2) drastically decreased the viability of C2C12 cells, but pre-treatment of CM-SD significantly increased the cell viability (p < 0.01). CM-SD significantly transactivated the nuclear factor erythroid-2-related factor 2 (Nrf2)-dependent luciferase activity in a dose-dependent manner and enhanced the levels of heme oxygenase (HO)-1, glutamate cysteine ligase catalytic subunit (GCLC), and NAD(P)H-dependent quinone oxidoreductase (NQO)-1. CM-SD also significantly reduced reactive oxygen species (ROS) production and lipid peroxidation and restored glutathione (GSH) depletion in H2O2-treated C2C12 cells. Moreover, CM-SD significantly reduced lipopolysaccharides (LPS)-mediated interleukin (IL)-6 production in the conditioned medium. Results from the current study suggest that CM-SD could be a useful candidate against oxidative stress and inflammation-related muscle disorders.

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Ganoderic Acid D Protects Human Amniotic Mesenchymal Stem Cells against Oxidative Stress-Induced Senescence through the PERK/NRF2 Signaling Pathway

Oxidative Medicine and Cellular Longevity ◽

10.1155/2020/8291413 ◽

2020 ◽

Vol 2020 ◽

pp. 1-18

Author(s):

Yan Xu ◽

Huan Yuan ◽

Yi Luo ◽

Yu-Jie Zhao ◽

Jian-Hui Xiao

Keyword(s):

Oxidative Stress ◽

Stem Cells ◽

Signaling Pathway ◽

Adult Stem Cells ◽

Telomerase Activity ◽

Related Factor ◽

Dependent Manner ◽

Ganoderic Acid ◽

Nrf2 Signaling Pathway

Aging is an important risk factor in the occurrence of many chronic diseases. Senescence and exhaustion of adult stem cells are considered as a hallmark of aging in organisms. In this study, a senescent human amniotic mesenchymal stem cell (hAMSC) model subjected to oxidative stress was established in vitro using hydrogen peroxide. We investigated the effects of ganoderic acid D (GA-D), a natural triterpenoid compound produced from Ganoderma lucidum, on hAMSC senescence. GA-D significantly inhibited β-galactosidase (a senescence-associated marker) formation, in a dose-dependent manner, with doses ranging from 0.1 μM to 10 μM, without inducing cytotoxic side-effects. Furthermore, GA-D markedly inhibited the generation of reactive oxygen species (ROS) and the expression of p21 and p16 proteins, relieved the cell cycle arrest, and enhanced telomerase activity in senescent hAMSCs. Furthermore, GA-D upregulated the expression of phosphorylated protein kinase R- (PKR-) like endoplasmic reticulum kinase (PERK), peroxidase III (PRDX3), and nuclear factor-erythroid 2-related factor (NRF2) and promoted intranuclear transfer of NRF2 in senescent cells. The PERK inhibitor GSK2656157 and/or the NRF2 inhibitor ML385 suppressed the PERK/NRF2 signaling, which was activated by GA-D. They induced a rebound for the generation of ROS and β-galactosidase-positive cells and attenuated the differentiation capacity. These findings suggest that GA-D retards hAMSC senescence through activation of the PERK/NRF2 signaling pathway and may be a promising candidate for the discovery of antiaging agents.

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Effect of fluoride on PERK-Nrf2 signaling pathway in mouse ameloblasts

Human & Experimental Toxicology ◽

10.1177/0960327119842273 ◽

2019 ◽

Vol 38 (7) ◽

pp. 833-845

Author(s):

X Zhou ◽

Z Chen ◽

W Zhong ◽

R Yu ◽

L He

Keyword(s):

Oxidative Stress ◽

Er Stress ◽

Signaling Pathway ◽

Nuclear Import ◽

Target Genes ◽

Dental Fluorosis ◽

Related Factor ◽

Dependent Manner ◽

Nrf2 Signaling Pathway ◽

Glutamylcysteine Synthetase

In the development of dental fluorosis, oxidative stress is considered as the key mechanism. Endoplasmic reticulum (ER) stress can induce oxidative stress and activate the important antioxidative factor nuclear factor erythroid 2-related factor 2 (Nrf2) in a PKR-like ER kinase (PERK)-dependent manner, but combining ER stress and oxidative stress, the role of PERK-Nrf2 signaling pathway involved in fluoride-regulated ameloblasts is not fully defined. Here, we studied the effect of fluoride on PERK-Nrf2 signaling pathway in mouse ameloblasts. We found that low-dose and continuous fluoride exposure increased binding immunoglobulin protein expression and activated PERK–activating transcription factor 4 signaling pathway. Meanwhile, the expression of Nrf2 and its target genes (glutamylcysteine synthetase and glutathione S-transferase-P1) enhanced following ER stress. Tunicamycin increased the expression of PERK, leading to Nrf2 nuclear import, and tauroursodeoxycholate suppressed Nrf2 activation through PERK during ER stress, indicating that PERK activation is required for Nrf2 nuclear entry. Furthermore, tert-butylhydroquinone triggered the overexpression of Nrf2 to reduce ER stress, but luteolin inhibited Nrf2 nuclear localization to elevate ER stress. In summary, this study proved that fluoride under certain dose can induce ER stress and promote Nrf2 nuclear import via PERK activation and suggested that antioxidation mechanism mediated by PERK-Nrf2 can alleviate fluoride-induced ER stress effectively.

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Ginsenoside Rg1 Protects Cardiomyocytes Against Hypoxia/Reoxygenation Injury via Activation of Nrf2/HO-1 Signaling and Inhibition of JNK

Cellular Physiology and Biochemistry ◽

10.1159/000484578 ◽

2017 ◽

Vol 44 (1) ◽

pp. 21-37 ◽

Cited By ~ 39

Author(s):

Qianhui Li ◽

Yin Xiang ◽

Yu Chen ◽

Yong Tang ◽

Yachen Zhang

Keyword(s):

Oxidative Stress ◽

Antioxidant Properties ◽

Heme Oxygenase 1 ◽

Related Factor ◽

Dependent Manner ◽

Ginsenoside Rg1 ◽

H9c2 Cells ◽

Stress Injury ◽

Mitochondrial Membrane Depolarization ◽

Hypoxia Reoxygenation

Background/Aims: Excessive reactive oxygen species (ROS) disturb the physiology of H9c2 cells, which is regarded as a major cause of H9c2 cardiomyocyte apoptosis. Ginsenoside Rg1 is the main active extract of ginseng, which has important antioxidant properties in various cell models. This project investigated the role of ginsenoside Rg1 in hypoxia/reoxygenation (H/R)-induced oxidative stress injury in cultured H9c2 cells to reveal the underlying signaling pathways. Methods: H9c2 cells were pretreated with ginsenoside Rg1 for 12 h before exposure to H/R. In the absence or presence of Nrf2siRNA, HO-1 inhibitor (ZnPP-IX), and inhibitors of the MAPK pathway (SB203580, PD98059, SP600125), H9c2 cells were subjected to H/R with Rg1 treatment. The effects and mechanisms of H/R-induced cardiomyocyte injury were measured. Results: Ginsenoside Rg1 treatment suppressed H/R-induced apoptosis and caspase-3 activation. Ginsenoside Rg1 treatment decreased ROS production and mitochondrial membrane depolarization by elevating the intracellular antioxidant capacity of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and reduced glutathione (GSH). Furthermore, ginsenoside Rg1 stimulation appeared to result in nuclear translocation of NF-E2-related factor 2 (Nrf2), along with enhanced expression of the downstream target gene heme oxygenase-1 (HO-1) in a dose-dependent manner. However, ginsenoside Rg1-mediated cardioprotection was abolished by Nrf2-siRNA and HO-1 inhibitor. H/R treatment increased the levels of phosphorylated c-Jun N-terminal kinases (p-JNK), which was dramatically attenuated by ginsenoside Rg1 and SP600125 (a specific JNK inhibitor). Conclusion: These observations indicate that ginsenoside Rg1 activates the Nrf2/HO-1 axis and inhibits the JNK pathway in H9c2 cells to protect against oxidative stress.

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Protective Effect of Decursin Extracted fromAngelica gigasin Male Infertility via Nrf2/HO-1 Signaling Pathway

Oxidative Medicine and Cellular Longevity ◽

10.1155/2016/5901098 ◽

2016 ◽

Vol 2016 ◽

pp. 1-9 ◽

Cited By ~ 13

Author(s):

Woong Jin Bae ◽

U. Syn Ha ◽

Jin Bong Choi ◽

Kang Sup Kim ◽

Su Jin Kim ◽

...

Keyword(s):

Oxidative Stress ◽

Semen Quality ◽

Antioxidant Activities ◽

Control Group ◽

Heme Oxygenase 1 ◽

Related Factor ◽

Dependent Manner ◽

Testicular Weight ◽

Unilateral Cryptorchidism

Higher testicular temperature results in altered spermatogenesis due to heat-related oxidative stress. We examined the effects of decursin extracted fromAngelica gigasNakai on antioxidant activityin vitroand in a cryptorchidism-induced infertility rat model. TM3 Leydig cell viability was measured based on oxidative stress according to treatment. Either distilled water or AG 400 mg/kg ofA. gigasextract was administered orally for 4 weeks after unilateral cryptorchidism was induced. After 1, 2, and 4 weeks, six rats from the control group and six rats from treatment group were sacrificed. Testicular weight, semen quality, antioxidant activities, nuclear factor erythroid 2-related factor 2 (Nrf2) protein, and mRNA expression of Nrf2-regulated genes were analyzed. Treatment withA. gigasextract (1) protected TM3 cells against oxidative stress in a dose-dependent manner, (2) improved the mean weight of the cryptorchid testis, (3) maintained sperm counts, motility, and spermatogenic cell density, (4) decreased levels of 8-hydroxy-2-deoxyguanosine (8-OHdG) and increased levels of superoxide dismutase (SOD), (5) significantly increased Nrf2 and heme oxygenase-1 (HO-1), and (6) significantly decreased apoptosis. This study suggests that decursin extracted fromA. gigasis a supplemental agent that can reduce oxidative stress by Nrf2-mediated upregulation of HO-1 in rat experimentally induced unilateral cryptorchidism and may improve cryptorchidism-induced infertility.

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Mini-GAGR, an intranasally applied polysaccharide, activates the neuronal Nrf2-mediated antioxidant defense system

Journal of Biological Chemistry ◽

10.1074/jbc.ra117.001245 ◽

2018 ◽

Vol 293 (47) ◽

pp. 18242-18269 ◽

Cited By ~ 6

Author(s):

Kelsey Murphy ◽

Killian Llewellyn ◽

Samuel Wakser ◽

Josef Pontasch ◽

Natasha Samanich ◽

...

Keyword(s):

Oxidative Stress ◽

Antioxidant System ◽

Cortical Neurons ◽

Hippocampal Neurons ◽

Nuclear Translocation ◽

Growth Factor Receptor ◽

Antioxidant Defense System ◽

Related Factor ◽

Dependent Manner ◽

Amyloid Aβ

Oxidative stress triggers and exacerbates neurodegeneration in Alzheimer's disease (AD). Various antioxidants reduce oxidative stress, but these agents have little efficacy due to poor blood–brain barrier (BBB) permeability. Additionally, single-modal antioxidants are easily overwhelmed by global oxidative stress. Activating nuclear factor erythroid 2 (NF-E2)-related factor 2 (Nrf2) and its downstream antioxidant system are considered very effective for reducing global oxidative stress. Thus far, only a few BBB-permeable agents activate the Nrf2-dependent antioxidant system. Here, we discovered a BBB-bypassing Nrf2-activating polysaccharide that may attenuate AD pathogenesis. Mini-GAGR, a 0.7-kDa cleavage product of low-acyl gellan gum, increased the levels and activities of Nrf2-dependent antioxidant enzymes, decreased reactive oxygen species (ROS) under oxidative stress in mouse cortical neurons, and robustly protected mitochondria from oxidative insults. Moreover, mini-GAGR increased the nuclear localization and transcriptional activity of Nrf2 similarly to known Nrf2 activators. Mechanistically, mini-GAGR increased the dissociation of Nrf2 from its inhibitor, Kelch-like ECH-associated protein 1 (Keap1), and induced phosphorylation and nuclear translocation of Nrf2 in a protein kinase C (PKC)- and fibroblast growth factor receptor (FGFR1)-dependent manner. Finally, 20-day intranasal treatment of 3xTg-AD mice with 100 nmol of mini-GAGR increased nuclear p-Nrf2 and growth-associated protein 43 (GAP43) levels in hippocampal neurons, reduced p-tau and β-amyloid (Aβ) peptide–stained neurons, and improved memory. The BBB-bypassing Nrf2-activating polysaccharide reported here may be effective in reducing oxidative stress and neurodegeneration in AD.

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Ezetimibe Prevents Ischemia/Reperfusion-Induced Oxidative Stress and Up-Regulates Nrf2/ARE and UPR Signaling Pathways

Antioxidants ◽

10.3390/antiox9040349 ◽

2020 ◽

Vol 9 (4) ◽

pp. 349 ◽

Cited By ~ 1

Author(s):

Denise Peserico ◽

Chiara Stranieri ◽

Ulisse Garbin ◽

Chiara Mozzini C ◽

Elisa Danese ◽

...

Keyword(s):

Oxidative Stress ◽

Gene Expression ◽

Cultured Cells ◽

Ischemia Reperfusion ◽

Cholesterol Absorption ◽

Antioxidant Response ◽

Related Factor ◽

Cellular Models ◽

Compound C ◽

Cholesterol Absorption Inhibitor

Background: While reperfusion is crucial for survival after an episode of ischemia, it also causes oxidative stress. Nuclear factor-E2-related factor 2 (Nrf2) and unfolded protein response (UPR) are protective against oxidative stress and endoplasmic reticulum (ER) stress. Ezetimibe, a cholesterol absorption inhibitor, has been shown to activate the AMP-activated protein kinase (AMPK)/Nrf2 pathway. In this study we evaluated whether Ezetimibe affects oxidative stress and Nrf2 and UPR gene expression in cellular models of ischemia-reperfusion (IR). Methods: Cultured cells were subjected to simulated IR with or without Ezetimibe. Results: IR significantly increased reactive oxygen species (ROS) production and the percentage of apoptotic cells without the up-regulation of Nrf2, of the related antioxidant response element (ARE) gene expression or of the pro-survival UPR activating transcription factor 6 (ATF6) gene, whereas it significantly increased the pro-apoptotic CCAAT-enhancer-binding protein homologous protein (CHOP). Ezetimibe significantly decreased the cellular ROS formation and apoptosis induced by IR. These effects were paralleled by the up-regulation of Nrf2/ARE and ATF6 gene expression and by a down-regulation of CHOP. We also found that Nrf2 activation was dependent on AMPK, since Compound C, a pan inhibitor of p-AMPK, blunted the activation of Nrf2. Conclusions: Ezetimibe counteracts IR-induced oxidative stress and induces Nrf2 and UPR pathway activation.

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

Biomolecules ◽

10.3390/biom9080380 ◽

2019 ◽

Vol 9 (8) ◽

pp. 380 ◽

Cited By ~ 4

Author(s):

Huang ◽

Chang ◽

Chau ◽

Chiu

Keyword(s):

Oxidative Stress ◽

Hydrogen Peroxide ◽

Protective Effect ◽

Retinal Pigment ◽

Heme Oxygenase 1 ◽

Related Factor ◽

Dependent Manner ◽

Glutamate Cysteine Ligase ◽

Jnk Pathway ◽

Nrf2 Signaling Pathway

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.

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