A mixture of extracts from natural ingredients reduces the neurotoxic polarization of microglia via modulating NF-κB/NF-E2-related factor 2 activation.

Neurotoxic microglia-provoked neuroinflammation is implicated in cognitive decline in Alzheimer's disease (AD). Supplementation with Ginkgo biloba, phosphatidylserine, Curcuma longa, and propolis is reported to improve the cognitive functions of elderly people; however, the underlying mechanisms of this combination of natural ingredients are unknown. We investigated the effects of a mixture of extracts from propolis, Coffea arabica, Gotu kola, phosphatidylserine, Ginkgo biloba, and Curcuma longa (mixture) on microglia polarization after exposure to amyloid ß1-42 (Aß1-42, 1 µM) and lipopolysaccharide from Porphyromonas gingivalis (PgLPS, 1 µg/mL), using MG6 and BV2 microglial cells. Exposure to Aß1-42 and PgLPS (AL) raised the mRNA expression of IL-1ß, TNF-α, and IL-6, nuclear translocation of p65 NF-κB in MG6 cells and BV2 cells, and mitochondrial reactive oxygen species (ROS) production in MG6 cells. The mixture dramatically suppressed the mRNA expression of IL-1ß, TNF-α, and IL-6, but significantly promoted that of IL-10, TGFß1, and BDNF in AL-exposed MG6 and BV2 cells. Furthermore, the mixture significantly suppressed the nuclear translocation of p65 NF-κB but significantly promoted that of NF-E2-related factor 2 (Nrf2) in AL-exposed MG6 and BV2 cells. Furthermore, the mixture significantly ameliorated mitochondrial ROS production but increased mitochondrial membrane potential in MG6 cells. These observations strongly suggest that the mixture demotes the neuropathic polarization of microglia by modulating NF-κB/Nrf2 activation and improving mitochondrial functions. This study supplies the potential mechanisms of the efficacy of a combination of natural ingredients that can be applied in the prevention of cognitive decline in AD and aging by targeting microglia-mediated neuroinflammation.

Sulforaphane upregulates the mRNA expression of NRF2 and NQO1 in non-dialysis patients with chronic kidney disease.

Sulforaphane (SFN), found in cruciferous vegetables, is a known activator of NRF2 (master regulator of cellular antioxidant responses). Patients with chronic kidney disease (CKD) present an imbalance in the redox state, presenting reduced expression of NRF2 and increased expression of NF-κB. Therefore, this study aimed to evaluate the effects of SFN on the mRNA expression of NRF2, NF-κB and markers of oxidative stress in patients with CKD. Here, we observed a significant increase in the mRNA expression of NRF2 (p = 0.02) and NQO1 (p = 0.04) in the group that received 400 µg/day of SFN for 1 month. Furthermore, we observed an improvement in the levels of phosphate (p = 0.02), glucose (p = 0.05) and triglycerides (p = 0.02) also in this group. On the other hand, plasma levels of LDL-c (p = 0.04) and total cholesterol (p = 0.03) increased in the placebo group during the study period. In conclusion, 400 µg/day of SFN for one month improves the antioxidant system and serum glucose and phosphate levels in non-dialysis CKD patients.

PHPB ameliorates memory deficits and reduces oxidative injury in Alzheimer's disease mouse model by activating Nrf2 signaling pathway.

Alzheimer's disease (AD), a progressive neurodegenerative disorder, is the most common cause of dementia in elderly people and substantially affects patient quality of life. Oxidative stress is considered a key factor in the development of AD. Nrf2 plays a vital role in maintaining redox homeostasis and regulating neuroinflammatory responses in AD. Previous studies show that potassium 2-(1-hydroxypentyl)-benzoate (PHPB) exerts neuroprotective effects against cognitive impairment in a variety of dementia animal models such as APP/PS1 transgenic mice. In this study we investigated whether PHPB ameriorated the progression of AD by reducing oxidative stress (OS) damage. Both 5- and 13-month-old APP/PS1 mice were administered PHPB (100 mg·kg-1·d-1, i.g.) for 10 weeks. After the cognition assessment, the mice were euthanized, and the left hemisphere of the brain was harvested for analyses. We showed that 5-month-old APP/PS1 mice already exhibited impaired performance in the step-down test, and knockdown of Nrf2 gene only slightly increased the impairment, while knockdown of Nrf2 gene in 13-month-old APP/PS1 mice resulted in greatly worse performance. PHPB administration significantly ameliorated the cognition impairments and enhanced antioxidative capacity in APP/PS1 mice. In addition, PHPB administration significantly increased the p-AKT/AKT and p-GSK3ß/GSK3ß ratios and the expression levels of Nrf2, HO-1 and NQO-1 in APP/PS1 mice, but these changes were abolished by knockdown of Nrf2 gene. In SK-N-SH APPwt cells and primary mouse neurons, PHPB (10 µM) significantly increased the p-AKT/AKT and p-GSK3ß/GSK3ß ratios and the level of Nrf2, which were blocked by knockdown of Nrf2 gene. In summary, this study demonstrates that PHPB exerts a protective effect via the Akt/GSK3ß/Nrf2 pathway and it might be a promising neuroprotective agent for the treatment of AD.

Supplementation of Clostridium butyricum Alleviates Vascular Inflammation in Diabetic Mice.

BACKGRUOUND: Gut microbiota is closely related to the occurrence and development of diabetes and affects the prognosis of diabetic complications, and the underlying mechanisms are only partially understood. We aimed to explore the possible link between the gut microbiota and vascular inflammation of diabetic mice. METHODS: The db/db diabetic and wild-type (WT) mice were used in this study. We profiled gut microbiota and examined the and vascular function in both db/db group and WT group. Gut microbiota was analyzed by 16s rRNA sequencing. Vascular function was examined by ultrasonographic hemodynamics and histological staining. Clostridium butyricum (CB) was orally administered to diabetic mice by intragastric gavage every 2 days for 2 consecutive months. Reactive oxygen species (ROS) and expression of nuclear factor erythroid-derived 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) were detected by fluorescence microscopy. The mRNA expression of inflammatory cytokines was tested by quantitative polymerase chain reaction. RESULTS: Compared with WT mice, CB abundance was significantly decreased in the gut of db/db mice, together with compromised vascular function and activated inflammation in the arterial tissue. Meanwhile, ROS in the vascular tissue of db/db mice was also significantly increased. Oral administration of CB restored the protective microbiota, and protected the vascular function in the db/db mice via activating the Nrf2/HO-1 pathway. CONCLUSION: This study identified the potential link between decreased CB abundance in gut microbiota and vascular inflammation in diabetes. Therapeutic delivery of CB by gut transplantation alleviates the vascular lesions of diabetes mellitus by activating the Nrf2/HO-1 pathway.

Grape Seed Proanthocyanidins Protect Pancreatic ß Cells Against Ferroptosis via the Nrf2 Pathway in Type 2 Diabetes.

Pancreatic ß cell damage is the primary contributor to type 2 diabetes mellitus (T2DM); however, the underlying mechanism remains nebulous. This study explored the role of ferroptosis in pancreatic ß cell damage and the protective effects of grape seed proanthocyanidin extract (GSPE). In T2DM model rats, the blood glucose, water intake, urine volume, HbA1c, and homeostasis model assessment-insulin resistance were significantly increased, while the body weight and the insulin level were significantly decreased, indicating the successful establishment of the T2DM model. MIN6 mouse insulinoma ß cells were cultured in high glucose and sodium palmitate conditions to obtain a glycolipid damage model, which was administered with GSPE, ferrostatin-1 (Fer-1), or nuclear factor erythroid 2-related factor 2 (Nrf2) small interfering (si) RNA. GSPE and Fer-1 treatment significantly improved pancreatic ß-cell dysfunction and protected against cell death. Both treatments increased the superoxide dismutase and glutathione activity, reduced the malondialdehyde and reactive oxygen species levels, and improved iron metabolism. Furthermore, the treatments reversed the expression of ferroptosis markers cysteine/glutamate transporter (XCT) and glutathione peroxidase 4 (GPX4) caused by glycolipid toxicity. GSPE treatments activated the expression of Nrf2 and related proteins. These effects were reversed when co-transfected with si-Nrf2. GSPE inhibits ferroptosis by activating the Nrf2 signaling pathway, thus reducing ß-cell damage and dysfunction in T2DM. Therefore, GSPE is a potential treatment strategy against T2DM.

Radiotherapy induces an increase in serum antioxidant capacity reflecting tumor response.

Background and purpose: Radiotherapy (RT) is a mainstay component of treatment for patients with head and neck squamous cell carcinoma (HNSCC), but responses vary. As RT relies upon oxidative damage, antioxidant expression in response to RT-induced reactive oxygen species (ROS) could compromise treatment response. We aimed to examine local and systemic antioxidant responses to increased RT-induced ROS in relation to treatment success. Materials and methods: Nuclear factor erythroid 2-related factor 2 (NRF2), the main antioxidant transcription factor, was immunofluorescently stained in FaDu cells and in tumor biopsies of patients with oral cavity/oropharynx HNSCC before and after five fractions of RT. Besides, total antioxidant capacity (TAC) was analyzed in HNSCC tumor cells in vitro and in serum of HNSCC patients before, during, and after RT. Results: Data revealed an increase in NRF2 expression and TAC in head and neck cancer cells in vitro over the course of 5 daily fractions of 2 Gy. In accordance, also in patients' tumors NRF2 expression increased, which was associated with increased serum TAC during RT. Increasing serum TAC was related to impaired local tumor control. Conclusion: Radiation induced NRF2 expression and upregulated TAC, which may compromise the effect of RT-induced ROS. Changes in serum TAC during RT could serve as a novel predictor of treatment outcome in HNSCC patients.Medical Ethics Review Committee (CMO) approval - CMO number: 2007/104.

Neferine inhibits the progression of diabetic nephropathy by modulating the miR-17-5p/nuclear factor E2-related factor 2 axis.

OBJECTIVE: To investigate the effect of Neferine (Nef) on diabetic nephropathy (DN) and to explore the mechanism of Nef in DN based on miRNA regulation theory. METHODS: A DN mouse model was constructed and treated with Nef. Serum creatinine (Crea), blood urea (UREA) and urinary albumin were measured in mice by kits, and renal histopathological changes and fibrosis were observed by hematoxylin-eosin staining and Masson staining. Renal tissue superoxide dismutase (SOD), malondialdehyde (MDA) and glutathione peroxidase (GSH-Px) activities were measured by enzyme-linked immunosorbent assay (ELISA). Western blotting was used to detect the expression of nuclear factor E2-related factor 2 (Nrf2)/ heme oxygenase 1 (HO-1) signaling pathway-related proteins in kidney tissues. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was used to detect the expression of miR-17-5p in kidney tissues. Subsequently, a DN in vitro model was constructed by high glucose culture of human mesangial cells (HMCs), cells were transfected with miR-17-5p mimic and/or treated with Nef, and we used qRT-PCR to detect cellular miR-17 expression, flow cytometry to detect apoptosis, ELISAs to detect cellular SOD, MDA, and GSH-Px activities, Western blots to detect Nrf2/HO-1 signaling pathway-related protein expression, and dual luciferase reporter gene assays to verify the targeting relationship between Nrf2 and miR-17-5p. RESULTS: Administration of Nef significantly reduced the levels of blood glucose, Crea, and UREA and the expression of miR-17-5p, improved renal histopathology and fibrosis, significantly reduced MDA levels, elevated SOD and GSH-Px activities, and activated Nrf2 expression in kidney tissues from mice with DN. Nrf2 is a post-transcriptional target of miR-17-5p. In HMCs transfected with miR-17-5p mimics, the mRNA and protein levels of Nrf2 were significantly suppressed. Furthermore, miR-17-5p overexpression and Nef intervention resulted in a significant increase in high glucose-induced apoptosis and MDA levels in HMCs and a significant decrease in the protein expression of HO-1 and Nrf2. CONCLUSION: Collectively, these results indicate that Nef has an ameliorative effect on DN, and the mechanism may be through the miR-17-5p/Nrf2 pathway.

The Nrf2 Pathway Alleviates Overloading Force-Induced TMJ Degeneration by Downregulating Oxidative Stress Reactions.

Objective: Oxidative stress is involved in the mechanisms associated with temporomandibular joint (TMJ) diseases. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a crucial oxidative stress marker, but the specific mechanisms of its regulation in the early stages of mandibular condylar cartilage (MCC) degeneration remain unclear. This study aimed to explore the regulatory role of Nrf2 and its related oxidative stress signaling pathway in the early stage of MCC degeneration. Materials and Methods: Overloading force-induced MCC degeneration was performed in wild-type and Nrf2 knockout mice, as well as in mice after treatment with the Nrf2 activator cardamonin. Changes in MCC degeneration and the expression of oxidative stress markers in the corresponding situations were observed. Results: Nrf2 and NADPH oxidase 2 (NOX2) expression were elevated during early MCC degeneration induced by an overloading force. MCC degeneration was aggravated when Nrf2 was knocked out, accompanied by increased NOX2 and superoxide dismutase 2 (SOD2) expression. The MCC degeneration process was alleviated after cardamonin treatment, with activation of the Nrf2 pathway and decreased NOX2 and SOD2 expression. Conclusion: Early MCC degeneration is accompanied by mild oxidative stress progression. Activated Nrf2 and related pathways could alleviate the degeneration of MCC.

High Expression of NRF2 and Low Expression of KEAP1 Predict Worse Survival in Patients With Operable Triple-Negative Breast Cancer.

PURPOSE: Triple-negative breast cancer (TNBC) is an aggressive type of breast cancer. Currently, no effective treatment options for this condition exist. Nuclear factor erythroid 2-related factor 2 (NRF2), encoded by nuclear factor erythroid-derived 2-like 2 (NFE2L2) gene and its endogenous inhibitor, Kelch-like ECH-associated protein 1 (KEAP1), both participate in cellular defense mechanisms against oxidative stress and contribute to chemoresistance and tumor progression in numerous types of cancers. This study aimed to evaluate the expression patterns of NRF2 and KEAP1 and their prognostic value in operable TNBC. METHODS: Tissue microarrays were prepared using tumor tissues collected from 203 patients with TNBC who underwent surgery. Immunohistochemical staining analyses of NRF2 and KEAP1 were performed. The expression of each immunomarker was categorized into two groups (low or high) based on the median H-score. We analyzed the association between the expression of each immunomarker and clinicopathological information to predict survival. A total of 225 TNBC samples from the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) dataset were used to validate our results. RESULTS: NRF2 immunoreactivity was detected in the nucleus and was associated with histologic grade and Ki-67 index, whereas KEAP1 immunoreactivity was detected in the cytoplasm and was associated with the Ki-67 index. Survival analyses showed that NRF2 and KEAP1 expressions were independent prognostic factors for overall survival (OS) (hazard ratio [HR], 2.45 and 0.30; p = 0.015 and 0.016, respectively) and disease-free survival (HR, 2.27 and 0.42; p = 0.019 and 0.022, respectively). NFE2L2 mRNA expression was an independent prognostic factor for OS (HR, 0.59; p = 0.009) in the METABRIC dataset. CONCLUSION: High NRF2 and low KEAP1 expressions independently predicted poor survival in patients with operable TNBC. Further investigations are warranted to examine the possible therapeutic benefits of targeting the KEAP1-NRF2 pathway for TNBC treatment.

Unraveling the protective role of Nrf2 in molluscs: Insights into mitochondrial and apoptosis pathways in the defense against Bap-induced oxidative stress.

Benzopyrene (Bap) is a major constituent of petroleum pollutants commonly found in aquatic environments, and its mutagenic and carcinogenic properties have adverse effects on aquatic organisms' development, growth, and reproduction. The antioxidant defense system element, NF-E2-related factor 2 (Nrf2), has been linked to the oxidative stress response in marine invertebrates exposed to toxic substances. In a previous study, a novel Nrf2 homologue, McNrf2, was identified in mussel Mytilus coruscus, a significant model marine molluscs in ecotoxicology studies. McNrf2 showed the potential to trigger an antioxidant defense against oxidative stress induced by Bap. Here, we employed an Nrf2 overexpression and inhibition model using SFN and ML385 as Nrf2 inducer and inhibitor, respectively. Next, immunofluorescence technique was used to evaluate the nuclear activation of Nrf2 induced by Bap-mediated oxidative stress. Transmission electron microscopy revealed that overexpression of Nrf2 could maintain the quantity and structural integrity of mitochondria, while flow cytometry analysis showed that Nrf2 could alleviate Bap-induced cellular apoptosis. These findings suggest that Nrf2 can protect molluscs from Bap-induced oxidative stress through the mitochondria and apoptosis pathways, providing a novel perspective on Nrf2's antioxidant function.

Effect of miR-27b-3p and Nrf2 in human retinal pigment epithelial cell induced by high-glucose.

AIM: To determine whether the microRNA-27b-3p (miR-27b-3p)/NF-E2-related factor 2 (Nrf2) pathway plays a role in human retinal pigment epithelial (hRPE) cell response to high glucose, how miR-27b-3p and Nrf2 expression are regulated, and whether this pathway could be specifically targeted. METHODS: hRPE cells were cultured in normal glucose or high glucose for 1, 3, or 6d before measuring cellular proliferation rates using cell counting kit-8 and reactive oxygen species (ROS) levels using a dihydroethidium kit. miR-27b-3p, Nrf2, NAD(P)H quinone oxidoreductase 1 (NQO1) and heme oxygenase-1 (HO-1) mRNA and protein levels were analyzed using reverse transcription quantitative polymerase chain reaction (RT-qPCR) and immunocytofluorescence (ICF), respectively. Western blot analyses were performed to determine nuclear and total Nrf2 protein levels. Nrf2, NQO1, and HO-1 expression levels by RT-qPCR, ICF, or Western blot were further tested after miR-27b-3p overexpression or inhibitor lentiviral transfection. Finally, the expression level of those target genes was analyzed after treating hRPE cells with pyridoxamine. RESULTS: Persistent exposure to high glucose gradually suppressed hRPE Nrf2, NQO1, and HO-1 mRNA and protein levels and increased miR-27b-3p mRNA levels. High glucose also promoted ROS release and inhibited cellular proliferation. Nrf2, NQO1, and HO-1 mRNA levels decreased after miR-27b-3p overexpression and, conversely, both mRNA and protein levels increased after expressing a miR-27b-3p inhibitor. After treating hRPE cells exposed to high glucose with pyridoxamine, ROS levels tended to decreased, proliferation rate increased, Nrf2, NQO1, and HO-1 mRNA and protein levels were upregulated, and miR-27b-3p mRNA levels were suppressed. CONCLUSION: Nrf2 is a downstream target of miR-27b-3p. Furthermore, the miR-27b-3p inhibitor pyridoxamine can alleviate high glucose injury by regulating the miR-27b-3p/Nrf2 axis.

An ERK5-NRF2 Axis Mediates Senescence-Associated Stemness and Atherosclerosis.

BACKGROUND: ERK5 (extracellular signal-regulated kinase 5) is a dual kinase transcription factor containing an N-terminal kinase domain and a C-terminal transcriptional activation domain. Many ERK5 kinase inhibitors have been developed and tested to treat cancer and inflammatory diseases. However, recent data have raised questions about the role of the catalytic activity of ERK5 in proliferation and inflammation. We aimed to investigate how ERK5 reprograms myeloid cells to the proinflammatory senescent phenotype, subsequently leading to atherosclerosis. METHODS: A ERK5 S496A (dephosphorylation mimic) knock in (KI) mouse model was generated using CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/clustered regularly interspaced short palindromic repeat-associated 9), and atherosclerosis was characterized by hypercholesterolemia induction. The plaque phenotyping in homozygous ERK5 S496A KI and wild type (WT) mice was studied using imaging mass cytometry. Bone marrow-derived macrophages were isolated from hypercholesterolemic mice and characterized using RNA sequencing and functional in vitro approaches, including senescence, mitochondria reactive oxygen species, and inflammation assays, as well as by metabolic extracellular flux analysis. RESULTS: We show that atherosclerosis was inhibited in ERK5 S496A KI mice. Furthermore, ERK5 S496 phosphorylation mediates both senescence-associated secretory phenotype and senescence-associated stemness by upregulating AHR (aryl hydrocarbon receptor) in plaque and bone marrow-derived macrophages isolated from hypercholesterolemic mice. We also discovered that ERK5 S496 phosphorylation could induce NRF2 (NFE2-related factor 2) SUMOylation at a novel K518 site to inhibit NRF2 transcriptional activity without altering ERK5 catalytic activity and mediates oxidized LDL (low-density lipoprotein)-induced senescence-associated secretory phenotype. Specific ERK5 kinase inhibitors (AX15836 and XMD8-92) also inhibited ERK5 S496 phosphorylation, suggesting the involvement of ERK5 S496 phosphorylation in the anti-inflammatory effects of these ERK5 kinase inhibitors. CONCLUSIONS: We discovered a novel mechanism by which the macrophage ERK5-NRF2 axis develops a unique senescence-associated secretory phenotype/stemness phenotype by upregulating AHR to engender atherogenesis. The finding of senescence-associated stemness phenotype provides a molecular explanation to resolve the paradox of senescence in proliferative plaque by permitting myeloid cells to escape the senescence-induced cell cycle arrest during atherosclerosis formation.

Effects of Exhaustive Exercise on Inflammatory, Apoptotic, and Antioxidative Signaling Pathways in Human Peripheral Blood Mononuclear Cells.

In the present study, we investigated the effects of exhaustive exercise and recovery on inflammatory, pro-apoptotic, and anti-oxidative responses in human peripheral blood mononuclear cells (PBMCs). Sixteen volunteers participated in a guided physical activity program in which they were subjected to progressive exercise on the treadmill until they were exhausted followed by an 1-hour recovery period. Isolated human PBMCs were collected before exercise, immediately after exercise, and after 1-hour recovery. Exhaustive exercise induced expression of heme oxygenase-1 and glutamate cysteine ligase catalytic subunit and activation of NF-κB and NF-E2 related factor 2 (Nrf2). Apoptosis, as measured by activity and cleavage of caspase-3 and its substrate PARP also significantly increased. However, induction of redox signaling and the pro-apoptotic response fully returned to the baseline level during the 1-hour recovery period. On the other hand, COX-2 expression was continuously elevated after exercise cessation throughout the 1-hour recovery period. Taking all these findings into account, we conclude that exhaustive exercise transiently induces Nrf2-mediated antioxidant gene expression and eliminates damaged cells through apoptosis as part of an adaptive cytoprotective response against oxidative and inflammatory stress.

Possible Involvement of Dermal Fibroblasts in Modulating Nrf2 Signaling in Epidermal Keratinocytes.

Epidermal keratinocytes protect themselves by cooperating with neighboring cells against internal and external stresses, which leads not only to the maintenance of cell homeostasis but also to the prevention of skin aging. Although it is known that nuclear factor (NF)-E2-related factor 2 (Nrf2) signaling plays a pivotal role in ameliorating oxidative stress and inflammatory responses under stress situations, it is unclear whether Nrf2 signaling in keratinocytes cooperates with neighboring cells such as dermal fibroblasts. Thus, this study was conducted to examine the influence of dermal fibroblasts on Nrf2 signaling in epidermal keratinocytes using a co-culture system. The results show that expression levels of Nrf2-regulated antioxidant factors, such as glutathione and heme oxygenase-1, in HaCaT keratinocytes (HaCaT KCs) are up-regulated in the presence of normal human dermal fibroblasts (NHDFs). In addition, the secretion of pro-inflammatory molecules, including interleukin-1α (IL-1α) and prostaglandin E2 (PGE2), is suppressed in co-cultures of NHDFs and UVB-irradiated HaCaT KCs. Interestingly, the localization of Nrf2 protein in HaCaT KCs was immediately translocated from the cytoplasm to the nucleus after the co-culture with NHDFs. These results suggest the possibility that Nrf2 signaling in keratinocytes is regulated in cooperation with dermal fibroblasts.

The nuclear factor E2-related factor 2 and age-related macular degeneration / O fator 2 relacionado a NF-E2 e a degeneração macular relacionada à idade

ABSTRACT After the discovery of anti-vascular endothelial growth factor agents as treatment of wet age-related macular degeneration, the number of studies with the objective to understand the molecular mechanisms involved in the age-re lated macular degeneration genesis has increased. The importance of the nuclear factor e2-related factor 2 lies in its activation-derived proteins being involved in the maintenance of the redox balance and consequent prevention of degenerative macular disease. This article aims to present the characteristics of nuclear factor e2-related factor 2 and describe the main nuclear factor e2-related factor 2-activated antioxidant enzymes that contribute to the preservation of vision.

RESUMO Após a descoberta do anti fator de crescimento en dotelial vascular no tratamento da degeneração macular relacionada à idade úmida, muitas pesquisas têm sido realizadas com o intuito de elucidar os mecanismos moleculares envolvidos na gênese da degeneração macular relacionada à idade. O fator nuclear eritroide 2 relacionado ao fator 2 destaca-se pelo fato de diversas proteínas, oriundas de sua ativação, estarem envolvidas na manutenção do equilíbrio do estado redox e consequente prevenção da doença macular degenerativa. Este artigo mostra as características do fator nuclear eritroide 2 relacionado ao fator 2 e descreve as principais enzimas antioxidantes originadas da ativação que contribuem para a preservação da visão.

Dimethyl Itaconate Inhibits Melanogenesis in B16F10 Cells.

Itaconate is a metabolite produced to counteract and resolve pro-inflammatory responses when macrophages are challenged with intracellular or extracellular stimuli. In the present study, we have observed that dimethyl itaconate (DMI) inhibits melanogenesis in B16F10 cells. DMI inhibits microphthalmia-associated transcription factor (MITF) and downregulates the expression of MITF target genes, such as tyrosinase (TYR), tyrosinase-related protein 1 (TRP-1), and tyrosinase-related protein 2 (TRP-2). DMI also decreases the level of melanocortin 1 receptor (MC1R) and the production of α-melanocyte stimulating hormone (α-MSH), resulting in the inhibition of extracellular signal-regulated kinase 1/2 (ERK1/2) and MITF activities. The structure-activity relationship (SAR) study illustrates that the α,ß-unsaturated carbonyl moiety in DMI, a moiety required to target KELCH-like ECH-associated protein 1 (KEAP1) to activate NF-E2-related factor 2 (NRF2), is necessary to inhibit melanogenesis and knocking down Nrf2 attenuates the inhibition of melanogenesis by DMI. Together, our study reveals that the MC1R-ERK1/2-MITF axis regulated by the KEAP1-NRF2 pathway is the molecular target responsible for the inhibition of melanogenesis by DMI.

Variable p53/Nrf2 crosstalk contributes to triptolide-induced hepatotoxic process.

This study was to investigate the potential mechanism of triptolide-induced hepatotoxicity. We found a novel and variable role of p53/Nrf2 crosstalk in triptolide-induced hepatotoxic process. Low doses of triptolide led to adaptive stress response without obvious toxicity, while high levels of triptolide caused severe adversity. Correspondingly, at the lower levels of triptolide treatment, nuclear translocation of Nrf2 as well as its downstream efflux transporters multidrug resistance proteins and bile salt export pump expressions were significantly enhanced, so did p53 pathways that also increased; at a toxic concentration, total and nuclear accumulations of Nrf2 decreased, while p53 showed an obvious nuclear translocation. Further studies showed the cross-regulation between p53 and Nrf2 after different concentrations of triptolide treatment. Under mild stress conditions, Nrf2 induced p53 highly expression to maintain the pro-survival outcome, while p53 showed no obvious effect on Nrf2 expression and transcriptional activity. Under high stress conditions, the remaining Nrf2 as well as the largely induced p53 mutually inhibited each other, leading to a hepatotoxic result. Nrf2 and p53 could physically and dynamically interact. Low levels of triptolide enhanced the interaction between Nrf2 and p53. Reversely, p53/Nrf2 complex dissociated at high levels of triptolide treatment. Altogether, variable p53/Nrf2 crosstalk contributes to triptolide-induced self-protection and hepatotoxicity, modulation of which may be a potential strategy for triptolide-induced hepatotoxicity intervention.

Sex-specific association of exposure to air pollutants and Nrf2 gene expression and inflammatory biomarkers in exhaled breath of healthy adolescents.

Studies investigating the nuclear factor erythroid 2-related factor 2 (Nrf2) expression levels in the respiratory system of healthy subjects are scarce. Moreover, separate studies on the health-related outcomes of air pollution for each sex are limited. The current panel study investigated sex-specific Nrf2 expression levels and related oxidative stress and inflammatory responses among healthy adolescents exposed to PM2.5, PM10, O3, and PM2.5-bounded metals in a high traffic region. Forty-nine healthy nonsmoking subjects participated in the study for five consecutive months (Nov. 2019 to Feb. 2020). Each subject was asked to provide 1 mL of exhaled breath condensate (EBC). Data were analyzed using linear mixed-effects models. The results showed that PM10, PM2.5, O3, and PM2.5-bounded metals were negatively linked to Nrf2 expression level in EBC of females with -58.3% (95% CI: 79.5, -15.4), -32.1% (95% CI: -50.3, -7.1), -76.2% (95% CI: -92.6, -23.9), and -1.9 (95% CI: -3.4, -0.4), respectively. While our results presented no significant association between the studied pollutants and Nrf2 gene expression in males, significant associations were observed between the pollutants and total nitric oxide (NOx), interleukins 6 (IL-6), and tumor necrosis factor-alpha (TNF-α) in the EBC of females. In the case of males, only EBC cytokines showed a significant association with air pollutants. Overall, this study suggests that exposure to ambient air pollutants may affect the respiratory system with biologically different mechanisms in males and females. PM2.5 concentration had a positive correlation with exhaled TNF-α and IL6 values in females while positive correlation with TNF-α and negative correlation with IL6 values in males. O3 had a negative correlation with TNF-α in males.

Curcumin intake during lactation suppresses oxidative stress through upregulation of nuclear factor erythroid 2-related factor 2 in the kidneys of fructose-loaded female rat offspring exposed to maternal protein restriction.

BACKGROUND: A high-fructose diet causes the progression of chronic kidney disease. Maternal malnutrition during pregnancy and lactation increases oxidative stress, leading to chronic renal diseases later in life. We investigated whether curcumin intake during lactation could suppress oxidative stress and regulate NF-E2-related factor 2 (Nrf2) expression in the kidneys of fructose-loaded female rat offspring exposed to maternal protein restriction. METHODS: Pregnant Wistar rats received diets containing 20% (NP) or 8% (LP) casein and 0 or 2.5 g "highly absorptive curcumin" /kg diet containing-LP diets (LP/LP or LP/Cur) during lactation. At weaning, female offspring received either distilled water (W) or 10% fructose solution (Fr) and were divided into four groups: NP/NP/W, LP/LP/W, LP/LP/Fr, and LP/Cur/Fr. At week 13, glucose (Glc), triacylglycerol (Tg), and malondialdehyde (MDA) levels in the plasma, macrophages number, fibrotic area, glutathione (GSH) levels, glutathione peroxidase (GPx) activity, protein expression levels of Nrf2, heme oxygenase-1 (HO-1), and superoxide dismutase 1 (SOD1) in the kidneys were examined. RESULTS: The plasma levels of Glc, TG, and MDA, the number of macrophages, and the percentage of fibrotic area in the kidneys of the LP/Cur/Fr group were significantly lower than those of the LP/LP/Fr group. The expression of Nrf2 and its downstream molecules HO-1 and SOD1, GSH levels, and GPx activity in the kidneys of the LP/Cur/Fr group were significantly higher than those of the LP/LP/Fr group. CONCLUSIONS: Maternal curcumin intake during lactation may suppress oxidative stress by upregulating Nrf2 expression in the kidneys of fructose-loaded female offspring exposed to maternal protein restriction.

Astragaloside IV mitigates cerebral ischaemia-reperfusion injury via inhibition of P62/Keap1/Nrf2 pathway-mediated ferroptosis.

Cerebral ischaemia-reperfusion injury (CIRI) is a critical component of ischaemic stroke pathogenesis. Ferroptosis contributes to and aggravates CIRI, whereas the P62/Kelch-like ECH-associated protein 1 (Keap1)/NF-E2-related factor 2 (Nrf2) pathway exerts neuroprotective effects. Astragaloside IV (AST IV) is the primary active ingredient of Astragalus, an herb with anti-CIRI properties used in traditional Chinese medicine. However, the mechanism of its anti-CIRI action is unclear. This study examined the mechanisms underlying the anti-CIRI action of AST IV using a combination of in vitro and in vivo approaches. We established an erastin-induced ferroptosis model, oxygen and glucose deprivation/reoxygenation (OGD/R)-induced model in SH-SY5Y cells, and middle cerebral artery occlusion-reperfusion (MCAO/R) model using Sprague-Dawley rats. The extent of cell damage and brain damage in rats, ferroptosis indicator changes, and expression of P62, Keap1, and Nrf2 were investigated. AST IV inhibited erastin-induced ferroptosis, attenuated OGD/R-induced cell damage, and ameliorated sensorimotor dysfunction and injury in the MCAO/R model. Further, AST IV promoted Nrf2 activation, inhibited ferroptosis, and reduced cell damage. Notably, these effects were inhibited by ML385, an Nrf2 inhibitor. AST IV increased the P62 and Nrf2 levels and decreased the Keap1 levels. P62 silencing reduced the effects of AST IV on the P62/Keap1/Nrf2 pathway and ferroptosis. Our findings suggest that AST IV mitigates CIRI by inhibiting ferroptosis via activation of the P62/Keap1/Nrf2 pathway. This study provides an important scientific basis and direction for the application and research of AST IV and provides new potential targets and ideas for the study of the pathological mechanism of CIRI.