Cell-specific regulation of Nrf2 during ROS-Dependent cell death caused by 2,3,5-tris(glutathion-S-yl)hydroquinone (TGHQ)

Alleviation of albumin glycation-induced diabetic cardiomyopathy by L-Arginine: Insights into Nrf-2 signaling

In hyperglycemia, accelerated glycation and oxidative stress give rise to many diabetic complications, such as diabetic cardiomyopathy (DCM). Glycated human serum albumin (GHSA) has disturbed structural integrity and hampered functional capabilities. When GHSA accumulates around cardiac cells, Nrf-2 is dysregulated, aiding oxidative stress. L-Arginine (L-Arg) is prescribed to patients with diabetes and cardiovascular diseases. This research contributes to the mechanistic insights on antiglycation and antioxidant potential of L-Arg in alleviating DCM. HSA was glycated with methylglyoxal in the presence of L-Arg (20-640 mM). Structural and functional modifications of HSA were studied. L-Arg and HSA, GHSA interactions, and thermodynamics were determined by steady-state fluorescence. H9c2 cardiomyocytes were given treatments of GHSA-L-Arg along with the inhibitor of the receptor of AGEs. Cellular antioxidant levels, detoxification enzyme activities were measured. Gene, protein expressions, and immunofluorescence data examined the activation and nuclear translocation of Nrf-2 during glycation and oxidative stress. L-Arg protected HSA from glycation-induced structural and functional modifications. The binding affinity of L-Arg was more towards HSA (104 M-1). L-Arg, specifically at lower concentration (20 mM), upregulated Nrf-2 gene, protein expressions and facilitated its nuclear translocation by activating Nrf-2 signaling. The study concluded that L-Arg can be of therapeutic advantage in glycation-induced DCM and associated oxidative stress.

Oral administration of grape-derived nanovesicles for protection against LPS/D-GalN-induced acute liver failure

Although the exploration of the molecular mechanisms of Acute liver failure (ALF) is supported by a growing number of studies, the lack of effective therapeutic agents and measures indicates an urgent clinical need for the development of new drugs and treatment strategies. Herein, we focused on the treatment of ALF with grape-derived nanovesicles (GDNVs), and assessed its protective effects and molecular mechanisms against liver injury. In the mice model of ALF, prophylactic administration for three consecutive days and treatment with GDNVs after successful induction of ALF showed a significant reduction of ALT and AST activity in mouse serum, as well as a blockade of the release of inflammatory cytokines IL6, IL-1β and TNF-α. Treatment with GDNVs significantly prevented the massive apoptosis of hepatocytes caused by LPS/D-GalN and down-regulated the activation and expression of the mitochondrial apoptosis-related proteins p53, Caspase 9, Caspase 8, Caspase 3 and Bax. GDNVs downregulated the release of chemokines during the inflammatory eruption in mice and inhibited the infiltration of peripheral monocytes into the liver by inhibiting CCR2/CCR5. Moreover, the pro-inflammatory phenotype of macrophages in the liver was reversed by GDNVs. GDNVs further reduced the activation of NLRP3-related pathways, and treatment with GDNVs activated the expression of autophagy-related proteins Foxo3a, Sirt1 and LC3-II in the damaged mouse liver, inducing autophagy to occur. GDNVs could exert hepatoprotective and inflammatory suppressive functions by increasing nuclear translocation of Nrf2 and upregulating HO-1 expression against exogenous toxin-induced oxidative stress in the liver. In conclusion, these results demonstrate that GDNVs alleviate LPS/D-GalN-induced ALF and have the potential to be used as a novel hepatoprotective agent for clinical treatment.

Shikonin promotes ferroptosis in HaCaT cells through Nrf2 and alleviates imiquimod-induced psoriasis in mice

Psoriasis is one kind of autoimmune skin disease without efficiency cure. Shikonin (SHK) is a potential drug for psoriasis treatment. Recent study suggested that ferroptosis involved in the pathological process of psoriasis. This study proved the beneficial effect of SHK with an imiquimod (IMQ) induced psoriatic model mice, and studied the ferroptosis regulative mechanism of SHK with a HaCaT cells assay in vitro. In the study, it also found that SHK treatment significantly improved imiquimod (IMQ)-induced psoriasis symptoms in mice, attenuated the production of inflammatory cytokines, including interleukin (IL)-6, IL-17, and tumor necrosis factor-alpha (i.e., TNF-α), and strongly inhibited macrophage infiltration in inflamed psoriatic skin. SHK impacted HaCaT cells (a human keratinocyte cell line) viability by enhancing intracellular and mitochondrial ferrous and lipid peroxidation levels by regulating expression of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), nuclear receptor coactivator 4 (NCOA4) and glutathione peroxidase 4 (GPX4) which could be reversed by iron chelating agent. and in psoriatic dermatitis. However, this study found the reversing capability of low dose SHK on LPS inhibited GPX4 and Nrf2 expression, which was identity to that in psoriatic dermatitis. To conclude, SHK inhibited ferroptosis in psoriatic skin by reducing inflammation, ameliorating oxidative stress and iron accumulation. Nrf2 and GPX4 might be the two major targets of SHK in psoriatic skin lesion. Our study highly lighted the basic biological mechanism of SHK on ferroptosis regulation.

Nesfatin-1 alleviates hyperoxia-induced lung injury in newborn mice by inhibiting oxidative stress through regulating SIRT1/PGC-1α pathway

Bronchopulmonary dysplasia (BPD) is a pulmonary disease commonly observed in premature infants and it is reported that oxidative stress is a critical induction factor in BPD and is considered as a promising target for treating BPD. Nesfatin-1 is a brain-gut peptide with inhibitory effects on food intake, which is recently evidenced to show suppressive effect on oxidative stress. The present study aims to explore the therapeutic effect and mechanism of Nesfatin-1 in BPD mice. AECIIs were extracted from newborn rats and exposed to hyperoxia for 24 h, followed by treatment with 5 and 10 nM Nesfatin-1. Declined cell viability, increased apoptotic rate, upregulated Bax, downregulated Bcl-2, increased release of ROS and MDA, and suppressed SOD activity were observed in hyperoxia-treated AECIIs, which were extremely reversed by Nesfatin-1. Newborn rats were exposed to hyperoxia, followed by treated with 10 μg/kg Nesfatin-1 and 20 μg/kg Nesfatin-1. Severe pathological changes, elevated MDA level, and declined SOD activity were observed in lung tissues of BPD mice, which were rescued by Nesfatin-1. Furthermore, the protective effect of Nesfatin-1 on hyperoxia-challenged AECIIs was abolished by silencing SIRT1. Collectively, Nesfatin-1 alleviated hyperoxia-induced lung injury in newborn mice by inhibiting oxidative stress through regulating SIRT1/PGC-1α pathway.

Methoxylated Modification of Glutathione-Mediated Metabolism of Halobenzoquinones In Vivo and In Vitro

Xenobiotics were generally detoxified in organisms through interaction with endogenous molecules, which may also generate metabolites of increased toxicity. Halobenzoquinones (HBQs), a group of highly toxic emerging disinfection byproducts (DBPs), can be metabolized by reacting with glutathione (GSH) to form various glutathionylated conjugates (SG-HBQs). In this study, the cytotoxicity of HBQs in CHO-K1 cells showed a wavy curve as a function of increased GSH dosage, which was inconsistent with the commonly recognized progressive detoxification curve. We hypothesized that the formation and cytotoxicity of GSH-mediated HBQ metabolites contribute to the unusual wave-shaped cytotoxicity curve. Results showed that glutathionyl-methoxyl HBQs (SG-MeO-HBQs) were identified to be the primary metabolites significantly correlated with the unusual cytotoxicity variation of HBQs. The formation pathway was initiated by stepwise metabolism via hydroxylation and glutathionylation to produce detoxified hydroxyl HBQs (OH-HBQs) and SG-HBQs, followed by methylation to generate SG-MeO-HBQs of potentiated toxicity. To further verify the occurrence of the aforementioned metabolism in vivo, SG-HBQs and SG-MeO-HBQs were detected in the liver, kidney, spleen, testis, bladder, and feces of HBQ-exposed mice, with the highest concentration quantified in the liver. The present study supported that the co-occurrence of metabolism can be antagonistic, which enhanced our understanding of the toxicity and metabolic mechanism of HBQs.

Maresin1 Protect Against Ferroptosis-Induced Liver Injury Through ROS Inhibition and Nrf2/HO-1/GPX4 Activation

Drugs, viruses, and chemical poisons stimulating live in a short period of time can cause acute liver injury (ALI). ALI can further develop into serious liver diseases such as cirrhosis and liver cancer. Therefore, how to effectively prevent and treat ALI has become the focus of research. Numerous studies have reported Maresin1 (MaR1) has anti-inflammatory effect and protective functions on organs. In the present study, we used d-galactosamine/lipopolysaccharide (D-GalN/LPS) to establish an ALI model, explored the mechanism of liver cells death caused by D-GalN/LPS, and determined the effect of MaR1 on D-GalN/LPS-induced ALI. In vivo experiments, we found that MaR1 and ferrostatin-1 significantly alleviated D-GalN/LPS-induced ALI, reduced serum alanine transaminase and aspartate transaminase levels, and improved the survival rate of mice. Meanwhile, MaR1 inhibited hepatocyte death, inhibited tissue reactive oxygen species (ROS) expression, reduced malondialdehyde (MDA), reduced glutathione (GSH), GSH/oxidized glutathione (GSSG), and iron content induced by D-GalN/LPS in mice. In addition, MaR1 inhibited ferroptosis-induced liver injury through inhibiting the release of interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and IL-6. Subsequently, western blot showed that MaR1 improved the expression of nuclear factor E2-related factor 2(Nrf2)/heme oxygenase-1 (HO-1)/glutathione peroxidase 4 (GPX4). In vitro experiments, we found that MaR1 inhibited LPS-induced and erastin-induced cell viability reduction. Meanwhile, we found that MaR1 increased the MDA and GSH levels in cells. Western blot showed that MaR1 increased the expression level of Nrf2/HO-1/GPX4. Next, the Nrf2 was knocked down in HepG2 cells, and the results showed that the protective effect of MaR1 significantly decreased. Finally, flow cytometry revealed that MaR1 inhibited ROS production and apoptosis. Overall, our study showed MaR1 inhibited ferroptosis-induced liver injury by inhibiting ROS production and Nrf2/HO-1/GPX4 activation.

Impaction of factors associated with oxidative stress on the pathogenesis of gestational hypertension and preeclampsia: A Chinese patients based study

We aimed to investigate the effect of Kelch-like ECH-associated protein 1/NF-E2 p45-related factor 2 (Keap1/Nrf2) pathway on the biological function of trophoblast cells in oxidative stress model at the cellular level, and analyzed the expression level and clinical significance of Keap1/Nrf2 pathway and related antioxidant factors in placental tissues of Preeclampsia (PE) patients at clinical level. In present study, we found that under hypoxia/reoxygenation conditions, the activity of oxidative stress-related enzymes (CAT, GSH-Px, SOD) in HTR8/SVneo cells was significantly lower than that before treatment (P < .01). The activities of CAT, GSH-Px and SOD in HTR8/SVneo cells in SiRNA+H/R group decreased significantly (P < .01), indicating the important defense effect of Keap1/Nrf2 signaling pathway in oxidative stress. As a control group of Nrf2 SiRNA+H/R group, Si-NC+H/R group had CAT, GSH-Px and SOD activities decreasing, which was similar to that in H/R group. Moreover, the activities of oxidative stress-related active enzymes in patients with PE were further confirmed by detecting and comparing the activities of CAT, GSH-Px and SOD in placental tissues. The results showed that the activity of SOD (P < .001), GSH-Px (P < .01) and CAT (P < .01) in placental tissues of patients with PE were significant different from those of normal placental tissues. The expression level of Keap1 in placenta of patients with PE was slightly lower than that of normal placenta. While the expression of Nrf2 in placenta of patients with PE was significantly higher than that of normal placenta. HO-1 expression in placenta of patients with PE was significantly higher than that of normal placenta. These results implicate the importance of Keap-1/Nrf2 pathway in PE.

Mechanism of oxidative stress and Keap-1/Nrf2 signaling pathway in bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is a chronic lung disease common in premature infants and is one of the leading causes of disability and death in newborns. The Keap-1/Nrf2 signaling pathway plays an important role in antioxidant and anti-inflammatory.Ten clean-grade, healthy pregnant Sprague-Dawley rats (purchased from Experimental Animal Center of Peking university, China) naturally gave birth to 55 neonatal rats from which 40 were selected and randomly divided into a hyperoxia group and a control group (N = 20, each). Thirty-two BPD patient samples are from Neonatal Department of the second Hospital of Jilin University from November 30, 2016 to May 1 2019.In present study, we observed that lung tissues of the control group did not undergo obvious pathological changes, whereas in the hyperoxia group, lung tissues had disordered structures. With increased time of hyperoxia exposure, the alveolar wall became attenuated. Under hypoxia conditions, the activity of oxidative stress-related enzymes (CAT, GSH-Px, SOD) in lung samples was significantly lower than that before treatment. The expression level of Keap1 mRNA and protein in the hyperoxia group was slightly lower than that of control group. The expression of Nrf2 and HO-1 mRNA and protein in the hyperoxia group was significantly higher than that of control group. For the infants with BPD, we found that the activity of SOD, GSH-Px, and CAT was significantly different from those of control group.We constructed a premature BPD animal model and found the abnormal of oxidative stress in different groups and the expression levels of Keap1/Nrf2 signaling pathway-related molecules, and we validated the results in premature infants with BPD.

Regulation of Keap-1/Nrf2 Signaling Pathway Is Activated by Oxidative Stress in Patients with Premature Rupture of Membranes

Background

The potential mechanisms underlying premature rupture of membrane (PROM) is still unknown. The aim of this study was to determine the role of Keap-1/Nrf2 signaling pathway activation by oxidative stress in patients with preterm premature rupture of membranes.

Material/Methods

Placental tissues from preterm premature rupture of membranes (PPROM) (n=20), full-term premature rupture of membranes (FPROM) (n=20), and normal-term births (n=20) were collected and amniotic tissues were separated from the placental tissues from pregnant women at Shandong Provincial Qianfoshan Hospital. RT-PCR and Western blot were used to detect the levels of factors in the Keap-1/Nrf2 signaling pathway. To investigate the roles of Nrf2, we downregulated Nrf2 expression using siRNA in primary human amniotic epithelial (HAE) cells.

Results

Among the control group, FPROM group, and PPROM group, the reactive oxygen species (ROS) levels were significantly increased in the FPROM and PPROM groups. The differences indicated higher levels of oxidative stress in amniotic tissues with FPROM and PPROM after downregulation of si-Nrf2 in HAE cells. Antioxidants were lower in amniotic tissues with the FPROM group and PPROM group than in the control group. The antioxidant enzymes catalase (CAT), glutathione (GSH), glutathione peroxidase (GSHPx), and superoxide dismutases (SOD1 and SOD2) were examined in amniotic tissues. We found that the ROS levels were significantly increased after downregulation of si-Nrf2 compared with the control group. We found that the expression of Heme Oxygenase-1 (HO-1) and Glycogen Synthase Kinase-3b (GSK-3b), which is critical in the Keap-1/Nrf2 signaling pathway, increased significantly after downregulation of si-Nrf2 in HAE cells.

Conclusions

We found that increased ROS levels and decreased antioxidant enzymes in the PPROM and FPROM patients compared with the control group.