The role of ANXA5 in DBP-induced oxidative stress through ERK/Nrf2 pathway

Di-N-butylphthalate (DBP) have given rise to more and more attention due to its unique endocrine toxicity to male reproductive system. Our previous studies have demonstrated antioxidative Nrf2 (nuclear factor erythroid related factor 2) pathway play a vital role in DBP induced oxidative stress injury. ANXA5 (annexin A5), which is highly expressed in testicular Leydig and Sertoli cells, was found upregulated after DBP stimulation. Mouse Leydig and Sertoli cells were exposed to different concentration of DBP for 24 h to examine the ROS (Reactive oxygen species), MDA (Malondialdehyde), SOD (superoxide dismutase) level and ANXA5, Nrf2, NQO1 (NAD(P)H-quinone oxidoreductase 1), HO-1 (heme oxygenase 1) and ERK/P-ERK protein expression by DHE (Dihydroethidium) staining, ELISA (enzyme-linked immunosorbent assay) and Western blot respectively. Firstly, the oxidative stress injury induced by DBP was re-validated. Then, we confirmed the change of Nrf2 pathway and ANXA5 level after DBP exposure to testicular cells. Additionally, overexpressed ANXA5 could activate Nrf2/HO-1/NQO1 antioxidant pathway and significantly attenuate DBP-induced oxidative stress. Ultimately, we demonstrated ANXA5 could increase ERK phosphorylated level and the activated role of ANXA5 on ERK/Nrf2 pathway could be reversed by ERK inhibitor. Overall, this study illuminated that ANXA5 could defend testicle Leydig and Sertoli cells against DBP-induced oxidative stress injury through ERK/Nrf2 pathway.     

转录因子Nrf2的神经保护作用及其机制

NF-E2相关因子2(Nrf2),感受体内反应活性氧(Reactive oxygen species,ROS)变化后,与体内的锚定蛋白Keap1解聚,发生核转位并调控下游多种抗氧化应激蛋白,解毒酶及转运体基因的表达,参与抗氧化应激生理及病理过程.目前,许多研究发现,Nrf2转录调控的下游靶基因可以对抗由脑中风氧化应激引起的神经系统病变,阿尔茨海默病(Alzheimer's disease),帕金森病(Parkinson's disease),侧索硬化(Amyotrophic lateral sclerosis,ALS).本文对近年来Nrf2在神经保护方面的作用及其机制,以及Nrf2作为药物治疗靶点治疗神经退行性病变的最新研究成果进行总结.     

Nrf2激活剂及其抗紫外线所致皮肤急性光损伤和慢性光老化的研究进展

紫外线（ultraviolet,UV）照射产生活性氧（reactive oxygen species,ROS）及自由基,与皮肤急性光损伤和慢性光老化发生密切相关。核因子E2相关因子2（nuclear factor erythroid 2-related factor 2,Nrf2）是调节抗氧化应激反应的重要转录因子,N...     

Induction of the Nrf2-driven antioxidant response by tert-butylhydroquinone prevents ethanol-induced apoptosis in cranial neural crest cells

Previous studies have shown that ethanol exposure causes apoptosis in cranial neural crest cells (NCCs), an ethanol-sensitive cell population implicated in Fetal Alcohol Spectrum Disorders (FASD). Additionally, induction of endogenous antioxidants through activation of nuclear factor-erythroid 2-related factor 2 (Nrf2) has been shown to prevent oxidative stress and apoptosis in ethanol-exposed mouse embryos. The objective of this study was to test whether tert-butylhydroquinone (tBHQ), an Nrf2 inducer, can protect NCCs against ethanol-induced apoptosis. Ethanol exposure was shown to cause a moderate increase in the protein expression of Nrf2 and its downstream antioxidants in the NCCs. Treatment of NCCs with tBHQ alone significantly increased the protein expression of Nrf2 and its downstream antioxidants and also significantly increased the activities of the antioxidant enzymes. In NCCs exposed to ethanol, the tBHQ-mediated antioxidant response prevented oxidative stress and apoptosis. These results clearly demonstrate that the activation of Nrf2 signaling confers protection against ethanol-induced apoptosis in NCCs.     

姜黄素对D-半乳糖致衰老大鼠氧化应激及Nrf2/ARE通路的影响

目的 研究姜黄素对D-半乳糖致衰老模型大鼠氧化应激及Nrf2/ARE通路的影响.方法 将大鼠随机均分为空白组、模型组和姜黄素组于模型组和姜黄素组大鼠每日sc 125 mg· kg-1D-半乳糖造模,姜黄素组大鼠同时ip 10 mg·kg-1姜黄素,空白组大鼠给予生理盐水,连续7周.测定各组大鼠血清中丙二醛(MDA)、肝组织中蛋白质糖基、谷胱甘肽过氧化物(GSH)的含量和血清超氧化物歧化酶(SOD)、全血谷胱甘肽过氧化物酶(GSH-Px)的活性;用Western blot法分析肝组织中Nrf2蛋白和HO-1蛋白的表达水平.结果 与模型组比较,姜黄素组大鼠血清中SOD的活性和MDA、肝中GSH、蛋白质羰基的含量均降低,全血中GSH-Px的活性显著升高,Nfr2和HO-1蛋白的表达水平也明显升高.结论 姜黄素能够缓解D-半乳糖导致的大鼠氧化应激,Nrf2/ARE通路参与了姜黄素的抗氧化活性.     

Fungicide prochloraz induces oxidative stress and DNA damage in vitro

Prochloraz is widely used in horticulture and agriculture, e.g. as a post-harvest anti-mold treatment. Prochloraz is a known endocrine disruptor causing developmental toxicity with multiple mechanisms of action. However, data are scarce concerning other toxic effects. Since oxidative stress response, with formation of reactive oxygen species (ROS), is a common mechanism for different toxic endpoints, e.g. genotoxicity, carcinogenicity and teratogenicity, the aim of this study was to investigate if prochloraz can induce oxidative stress and/or DNA damage in human cells. A cell culture based in vitro model was used to study oxidative stress response by prochloraz, as measured by the activity of the nuclear factor erythroid 2-related factor 2 (Nrf2), a key molecule in oxidative defense mechanisms. It was observed that prochloraz induced oxidative stress in cultured human adrenocortical H295R and hepatoma HepG2 cells at non-toxic concentrations. Further, we used Comet assay to investigate the DNA damaging potential of prochloraz, and found that non-toxic concentrations of prochloraz induced DNA damage in HepG2 cells. These are novel findings, contradicting previous studies in the field of prochloraz and genotoxicity. This study reports a new mechanism by which prochloraz may exert toxicity. Our findings suggest that prochloraz might have genotoxic properties.     

Ginsenoside Rg1 prevents acetaminophen-induced oxidative stress and apoptosis via Nrf2/ARE signaling pathway

Inappropriate use of acetaminophen (APAP) can lead to morbidity and mortality secondary to hepatic necrosis. Ginsenoside Rg1 is a major active ingredient in processed Panax ginseng, which is proved to elicit biological effects. We hypothesized the beneficial effect of Rg1 on APAP-mediated hepatotoxicity was through Nrf2/ARE pathway. The study was conducted in cells and mice, comparing the actions of Rg1. Rg1 significantly improved cell survival rates and promoted the expression of antioxidant proteins. Meanwhile, Rg1 reduced the excessive ROS and the occurrence of cell apoptosis, which were related to Nrf2/ARE pathway. Expression of Nrf2 has a certain cell specificity.

     

Icaritin activates Nrf2/Keap1 signaling to protect neuronal cells from oxidative stress

Our earlier study indicated that icaritin (ICT) protected mice from cerebral ischemic injury by inhibiting oxidative stress, and this study aimed to investigate its mechanism using a H₂O₂‐treated SH‐SY5Y cells model. Cell viability was assessed by cell counting kit 8 (CCK‐8). Oxidative stress parameters were detected by flow cytometry, and signaling pathways were analyzed by immunoblotting. We found that ICT alleviated apoptosis and intracellular and mitochondrial reactive oxygen species (ROS) levels, decreased the expressions of Bax and cleaved caspase‐3, and increased the expressions of Bcl‐2 compared to H₂O₂ group. ICT increased mitochondrial membrane potential (ΔΨm) and blocked the opening of mitochondrial membrane permeability transporter (MPT), and increased the activity of glutathione peroxidase (GSH‐px), catalase (CAT), and superoxide dismutase (SOD), meanwhile, decreased the activity of malondialdehyde (MDA) compared to H₂O₂ group. Further investigation revealed that ICT significantly up‐regulated the expressions of nuclear factor erythroid 2‐related factor 2 (Nrf2), heme oxygenase 1 (HO‐1) and NAD(P)H‐quinone oxidoreductase 1 (NQO‐1). The anti‐apoptosis and antioxidative effects of ICT were blocked bay ML385, a Nrf2/Keap1 signaling pathway inhibitor. These results indicate that ICT can play a neuroprotective role against oxidative stress injury by activating Nrf2/Keap1 signaling pathway.     

叔丁基对苯二酚对糖尿病小鼠肾脏氧化应激损伤及Nrf2蛋白表达的影响

目的研究叔丁基对苯二酚(tBHQ)对早期糖尿病小鼠肾脏Nrf2-ARE信号通路表达及氧化应激的影响,探讨tBHQ保护肾脏的部分机制。方法CD-1♂小鼠随机分为3组,对照组(C组)、糖尿病组(DM组)、tBHQ干预组(DM+tBHQ组)。腹腔注射STZ诱发糖尿病小鼠模型,DM+tBHQ组在成模3d后给予添加了1%tBHQ(W/W)的饲料喂养,4wk后检测3组动物的血糖、肾功能、24h尿白蛋白定量、血清及肾皮质丙二醛(MDA)含量。免疫组化和Westernblot检测Nrf2,HO-1蛋白在肾组织的定位和表达水平。结果①DM组小鼠血尿素氮、24h尿白蛋白定量、肾重/体重,血清及肾皮质MDA含量较C组升高。tBHQ干预组上述指标均降低。②与DM组相比,tBHQ干预组肾皮质总蛋白Nrf2、HO-1及核蛋白Nrf2表达水平明显增高;免疫组织化学检测显示Nrf2于肾小管及肾小球的胞质及胞核内均有表达;HO-1主要表达于肾小管上皮细胞胞质中。结论tBHQ减轻了早期糖尿病小鼠肾脏的氧化应激损伤,其作用机制可能是部分通过激活Nrf2-ARE信号通路进而增强抗氧化蛋白HO-1的表达而实现的。     

Poria cocos polysaccharides attenuated ox-LDL-induced inflammation and oxidative stress via ERK activated Nrf2/HO-1 signaling pathway and inhibited foam cell formation in VSMCs

Oxidative stress, inflammation, and foam cell formation in vascular smooth muscle cells (VSMCs) are considered to play crucial roles in the pathogenesis of atherosclerosis. Poria cocos polysaccharides (PCP) has been shown to possess anti-inflammatory, antitumor and anti-oxidative properties. In this study we explored the effects of PCP on ox-LDL-induced inflammation, oxidative stress and foam cell formation in VSMCs. PCP significantly attenuated ox-LDL-induced oxidative stress, as evidenced by the decreased reactive oxygen species (ROS) and MDA levels, and the increased SOD activity in VSMCs. PCP suppressed the induction effect of ox-LDL on inflammatory cytokines and inflammatory mediators. PCP also substantially inhibited VSMCs foam cell formation and intracellular lipids accumulation. Mechanistically, PCP suppressed ox-LDL-induced up-regulation of LOX-1, which is responsible for ox-LDL uptake. Western blotting suggested that PCP activated ERK1/2 signaling pathway, increased Nrf2 translocated from cytoplasm to nucleus and heme oxygenase-1 (HO-1) expression. Up-regulation of PCP on Nrf2/HO-1 signaling was reversed by pretreatment with ERK inhibitor PD98059, indicating the involvement of ERK in PCP activation of Nrf2/HO-1 signaling. In conclusion, these results demonstrated that PCP exerted its protection against oxidative stress and inflammation via the ERK/Nrf2/HO-1 signaling pathway and that PCP may be a promising candidate for the therapy of atherosclerosis.     

黄连素激活Nrf2通路缓解新生大鼠哮喘模型氧化应激反应和对心肺组织的保护作用

目的：探讨黄连素（berberine,BB）对新生大鼠哮喘模型氧化应激反应的影响和对心肺组织的保护作用以及潜在的分子机制。方法：将新生SD雄性大鼠随机分成健康对照组、健康加药组、哮喘模型组和模型加药组;卵清蛋白诱导新生大鼠哮喘模型;收集肺泡灌洗液（broncho alveokar lavage fluid,BALF）并分析细胞类型和细胞数目;苏木伊红（hematoxylin eosin,HE）染色观察心肌组织和肺组织病理变化;末端标记法（terminal deoxynucleoitidyl transferase mediated nick end labeling,TUNEL）染色检测心肌组织和肺组织细胞凋亡情况;试剂盒检测血清中超氧化物歧化酶（superoxide dismutase,SOD）的活性和丙二醛（malondialdehyde,MDA）、一氧化氮（nitric oxide,NO）的含量;蛋白质印记检测肺组织中Kelch样ECH相关蛋白1（Kelch-like ECH-associated protein 1,Keap1）、NFE2相关因子2（NF-E2 related factor 2,Nrf2）和血红素氧合酶1（heme oxygenase 1,HMOX-1）的表达水平。结果：哮喘模型组与对照组相比,肺泡灌洗液中炎性细胞的数目显著增加;心肌组织细胞排列不规则,部分细胞结构不清晰;肺组织中有大量的炎性细胞浸润,黏膜下水肿,气道上皮断裂脱落,支气管壁明显增厚;心肌组织和肺组织中凋亡细胞比例显著增加;血清中SOD的活性显著降低,MDA和NO的含量显著增加;肺组织中Keap1、Nrf2和HMOX-1的表达水平显著升高。模型加药组与模型组相比,肺泡灌洗液中炎性细胞的数目明显减少;心肌组织较规则,细胞排列较整齐;肺组织中仍有部分炎性细胞浸润,部分肺泡壁增厚;心肌组织和肺组织中凋亡细胞比例显著降低;SOD的活性显著升高,MDA和NO的含量显著降低;Keap1、Nrf2和HMOX-1的表达水平显著升高。结论：黄连素可激活Nrf2通路,缓解新生大鼠哮喘模型的氧化应激反应,对心肺组织具有保护作用。     

Hepatoprotective potentials of Phyllanthus amarus against ethanol-induced oxidative stress in rats

The hepatoprotective effect of methanolic extract of the leaf of Phyllanthus amarus (P. amarus) against ethanol-induced oxidative damage was investigated in adult male Wistar albino rats. P. amarus (250 and 500 mg/kg/day) and ethanol (5 g/kg/day, 20% w/v) were administered orally to animals for 4 weeks and 3 weeks, respectively. Ethanol treatment markedly decreased the level of reduced glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT) in the liver, which were significantly enhanced by P. amarus treatment. Glutathione-S transferase (GST), which was increased after chronic ethanol administration, was significantly reduced by P. amarus treatment in the liver. Also, P. amarus significantly increased the activities of hepatic alanine transaminase (ALT) and aspartate transaminase (AST) as well as alkaline phosphatase (ALP), with a concomitant marked reduction in the plasma activity of the transaminases in the ethanol-challenged rats. Lipid peroxidation level, which was increased after chronic ethanol administration, was significantly reduced in the liver by P. amarus co-treatment. Results show that P. amarus leaf extract could protect the liver against ethanol-induced oxidative damage by possibly reducing the rate of lipid peroxidation and increasing the antioxidant defence mechanism in rats.     

Generation of stable ARE- driven reporter system for monitoring oxidative stress

Background

NF-E2-related factor2 (Nrf2)-antioxidant response element (ARE) signaling pathway is the major defensive mechanism against oxidative stress and is up regulated by specific antioxidants and oxidants to comprise the chemoptotective response. Detection of ARE-activating compounds helps to develop new drugs and identify/quantify the tension range of the oxidants.Important reasons promoting this work are high throughput, rapid and inexpensive experiments relative to the in vitro studies for ARE-Nrf2 pathway monitoring of chemicals and environmental samples.

Methods

In this study hepatoma Huh7 reporter cell line was generated which contains a luciferase gene under the control of an ARE. This is the first example of ARE construct containing one copy of extended consensus response element. The cells were treated with hydroquinone (HQ) and p-benzoquinone (BQ) (oxidative stress inducers) and the antioxidant, curcumin.

Results

The luciferase activity was induced in a concentration-dependent manner in a concentration range of 1–2 μM for BQ and HQ. Curcumin was also validated as an ARE inducer in concentration above 10 μM. In addition, this reporter cell line provides a rapid detection as early as 4 h to respond to the ARE inducers.

Conclusion

It is a powerful tool for the sensitive and selective screening of chemicals, drugs and environmental samples for their antioxidant and oxidant activities.