Nuclear Factor Erythroid 2p45 Research Articles

Ketogenic diet alleviates cognitive dysfunction and neuroinflammation in APP/PS1 mice via the Nrf2/HO-1 and NF-κB signaling pathways.

Alzheimer's disease is a progressive neurological disorder characterized by cognitive decline and chronic inflammation within the brain. The ketogenic diet, a widely recognized therapeutic intervention for refractory epilepsy, has recently been proposed as a potential treatment for a variety of neurological diseases, including Alzheimer's disease. However, the efficacy of ketogenic diet in treating Alzheimer's disease and the underlying mechanism remains unclear. The current investigation aimed to explore the effect of ketogenic diet on cognitive function and the underlying biological mechanisms in a mouse model of Alzheimer's disease. Male amyloid precursor protein/presenilin 1 (APP/PS1) mice were randomly assigned to either a ketogenic diet or control diet group, and received their respective diets for a duration of 3 months. The findings show that ketogenic diet administration enhanced cognitive function, attenuated amyloid plaque formation and proinflammatory cytokine levels in APP/PS1 mice, and augmented the nuclear factor-erythroid 2-p45 derived factor 2/heme oxygenase-1 signaling pathway while suppressing the nuclear factor-kappa B pathway. Collectively, these data suggest that ketogenic diet may have a therapeutic potential in treating Alzheimer's disease by ameliorating the neurotoxicity associated with Aβ-induced inflammation. This study highlights the urgent need for further research into the use of ketogenic diet as a potential therapy for Alzheimer's disease.

Evaluation of Nrf2, Keap1 and Apoptotic Pathway Genes Expression in Acute Myeloid Leukemia Patients

The aim of this study was to evaluate the expression Nrf2 (Nuclear factor-erythroid 2-p45 derived factor 2) and Keap1 (Kelch-like ECH-associated protein 1) genes and Bcl-2 (B-cell lymphoma 2), Bcl-XL (B-cell lymphoma-extra large), Bax (Bcl2-associated X protein) apoptotic pathway genes in acute myeloid leukemia patients. In this case-control study, the expression of genes encoding Nrf2, Keap1, Bcl2, Bcl- XL and Bax in 40 acute myeloid leukemia (AML) patients were compared with 40 normal individuals in the Iranian population. We evaluated the mRNA expression of genes by using the real-time quantitative polymerase chain reaction. The expression of Nrf2, Bcl2 and Bcl- XL genes in new AML patients were increased (p < 0.05). The patients treated with chemotherapy had a significantly more than four times higher expression level of Nrf2 than new case patients (P < 0.05), while there was a decrease in the expression level of Bcl2 and Bcl-XL, which was not statistically significant. In other hands in relapsed patients, the expressions of Nrf2, Bcl2 and Bcl- XL were higher level than new case patients (p < 0.05) but this was less than patients treated with chemotherapy (p > 0.05). The high levels of mentioned genes may be associated with poor treatment response, chemoresistance and disease recurrence. Because of hyperactivation and overexpression of Nrf2 in leukemia, suggest that Nrf2 inhibitors could be used as a pharmacological target in combination with classical chemotherapeutic agents to increase the efficacy of anticancer therapy.

Apigenin protects human melanocytes against oxidative damage by activation of the Nrf2 pathway.

Vitiligo is a chronic, autoimmune destruction of melanocytes, resulting in progressively expanding depigmented skin patches. Severity of the disorder, which affects approximately 1% of humans, may be mitigated using topical corticosteroids combined with phototherapy; along with other clinical strategies; however, no definitive cures are currently available. Here, the capacity of apigenin, a plant-derived aglycone, to inhibit oxidative stress-mediated melanocyte depletion in vitro using a PIG3V vitiligo perilesional melanocyte cell model is evaluated. PIG3V cells, treated with selected doses of apigenin, were challenged with H2O2, then assessed for viability and the oxidative stress-related parameters: superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) by enzyme-linked immunoabsorbent assay (ELISA). Additionally, expression of nuclear factor erythroid 2p45 (NF-E2)-related factor 2 (Nrf2) and downstream targets was detected using Western blotting. Outcomes demonstrated that compared with negative control cultures, apigenin-treated cells exhibited enhanced viability. Likewise, apigenin enhanced expression of the cellular anti-oxidants SOD, CAT, and GSH-Px, but inhibited production of MDA, an oxidative stress biomarker. Interestingly, the expression and nuclear localization of the Nrf2 transcription factor, an important regulator oxidative stress and its downstream target genes, was significantly increased by apigenin treatment. Apigenin influence on Nrf2 was further validated by experiments demonstrating that Nrf2 knockdown cells failed to exhibit significant apigenin-mediated effects on cell viability and oxidative stress. Apigenin's non-toxicity and ability to affect multiple oxidative stress-related parameters through its effects on Nrf2 signaling in melanocytes suggests that it may prove to be a valuable therapeutic tool in long-term management of vitiligo.

Air pollution-derived PM2.5 impairs mitochondrial function in healthy and chronic obstructive pulmonary diseased human bronchial epithelial cells

In order to clarify whether the mitochondrial dysfunction is closely related to the cell homeostasis maintenance after particulate matter (PM2.5) exposure, oxidative, inflammatory, apoptotic and mitochondrial endpoints were carefully studied in human bronchial epithelial BEAS-2B, normal human bronchial epithelial (NHBE) and chronic obstructive pulmonary disease (COPD)-diseased human bronchial epithelial (DHBE) cells acutely or repeatedly exposed to air pollution-derived PM2.5. Some modifications of the mitochondrial morphology were observed within all these cell models repeatedly exposed to the highest dose of PM2.5. Dose- and exposure-dependent oxidative damages were reported in BEAS-2B, NHBE and particularly COPD-DHBE cells acutely or repeatedly exposed to PM2.5. Nuclear factor erythroid 2-p45 related factor 2 (NRF2) gene expression and binding activity, together with the mRNA levels of some NRF2 target genes, were directly related to the number of exposures for the lowest PM2.5 dose (i.e., 2 μg/cm2), but, surprisingly, inversely related to the number of exposures for the highest dose (i.e., 10 μg/cm2). There were dose- and exposure-dependent increases of both nuclear factor kappa-B (NF-κB) binding activity and NF-κB target cytokine secretion in BEAS-2B, NHBE and particularly COPD-DHBE cells exposed to PM2.5. Mitochondrial ROS production, membrane potential depolarization, oxidative phosphorylation, and ATP production were significantly altered in all the cell models repeatedly exposed to the highest dose of PM2.5. Collectively, our results indicate a cytosolic ROS overproduction, inducing oxidative damage and activating oxygen sensitive NRF2 and NF-kB signaling pathways for all the cell models acutely or repeatedly exposed to PM2.5. However, one of the important highlight of our findings is that the prolonged and repeated exposure in BEAS-2B, NHBE and in particular sensible COPD-DHBE cells further caused an oxidative boost able to partially inactivate the NRF2 signaling pathway and to critically impair mitochondrial redox homeostasis, thereby producing a persistent mitochondrial dysfunction and a lowering cell energy supply.

Anti-Inflammatory Mechanism Involved in Pomegranate-Mediated Prevention of Breast Cancer: the Role of NF-κB and Nrf2 Signaling Pathways.

Pomegranate (Punica granatum L.), a nutrient-rich unique fruit, has been used for centuries for the prevention and treatment of various inflammation-driven diseases. Based on our previous study, a characterized pomegranate emulsion (PE) exhibited a striking inhibition of dimethylbenz(a)anthracene (DMBA)-initiated rat mammary tumorigenesis via antiproliferative and apoptosis-inducing mechanisms. The objective of the present work is to investigate the anti-inflammatory mechanism of action of PE during DMBA rat mammary carcinogenesis by evaluating the expression of cyclooxygenase-2 (COX-2), heat shock protein 90 (HSP90), nuclear factor-κB (NF-κB) and nuclear factor erythroid 2p45 (NF-E2)-related factor 2 (Nrf2). Mammary tumor samples were harvested from our previous chemopreventive study in which PE (0.2–5.0 g/kg) was found to reduce mammary tumorigenesis in a dose-dependent manner. The expressions of COX-2, HSP90, NF-κB, inhibitory κBα (IκBα) and Nrf2 were detected by immunohistochemical techniques. PE decreased the expression of COX-2 and HSP90, prevented the degradation of IκBα, hindered the translocation of NF-κB from cytosol to nucleus and increased the expression and nuclear translocation of Nrf2 during DMBA-induced mammary tumorigenesis. These findings, together with our previous results, indicate that PE-mediated prevention of DMBA-evoked mammary carcinogenesis may involve anti-inflammatory mechanisms through concurrent but differential regulation of two interrelated molecular pathways, namely NF-κB and Nrf2 signaling.

Therapeutic Potential for Modulation of Nrf2-Keap-1 Signaling Pathway as Treatment for Diabetes and Other Disorders.

Summary: Theinventioninthispatentapplicationisrelatedtonaphthylsulfonamidepyrrolidinederivativesrepresentedgenerallybyformula(I). ThesecompoundsareKeap-1modulatorsandmaybeusefulforthepreventionand/ortreatmentofdiabetes,obesity,dyslipidemia, and related disorders as well as neuroinflammatory and neurodegenerative diseases such as multiple sclerosis, Alzheimer’s disease, Parkinson’s disease, and Huntington’s disease. The transcription factor nuclearfactor erythroid2 p45 (NF-E2)-related factor (Nrf2) is a cellular sensor ofoxidative and electrophilic stress. It is a member of the Cap ‘n’ collar family of basic leucine zipper transcription factors, and it is critical for the expression of severalcytoprotectivegenes.Nrf2isregulatedbytheKelch-likeECH-associatedprotein1(Keap-1),whichisanadaptorproteinof the cullin 3-dependent ubiquitin E3 ligase complex. Keap-1 contains functional domains, including a broad complex/tramtrack/ Bric-a-Brac (BTB) domain, an intervening region (IVR) domain, and a Kelch domain. Ubiquitin is the original member of a family of small proteins, which are found in most cellular tissues in the human body that help in regulating the processes of other cellular proteins. Ubiquitin and other relative molecules add covalently to cellular proteins in a process known as ubiquitinylation that alters their activities and the functions. This process plays a critical role in apoptosis of proteinsaswell asin severalothercellularprocesses relatedtothe regulationofproteins.Keap-1mediatesthe ubiquitinylationand subsequentdegradationofNrf2bythe26Sproteasome.Inthisinteraction,theKelchdomainonaKeap-1homodimerbindstothe DLGandETGEsequencemotivesofNrf2molecule.TheKeap-1BTBdomaincontainsacysteineresidueatthe151position,while theIVRdomaincontainstwocysteineresidues,Cys273andCys288.WhileKeap-1hasothercysteineresidues,thesethreeresidues arehighlyreactiveandplaycriticalrolesinstresssensing.Theyaremodifiedinresponsetooxidativestressorelectrophilicreagents, and that alters the conformation of Keap-1, inhibits its function, and prevents the degradation of Nrf2. This leads to the translocation of Nrf2 into the nucleus and its subsequent activation. Nrf2 binds to the antioxidant response element (ARE) in the nucleusanddrivestheexpressionofNrf2targetgenessuchasNAD(P)Hquinoneoxidoreductase1(NQO1)andhemeoxygenase 1 (HMOX1), which are upregulated by the activation of Nrf2. The activation of Nrf2 may provide a potential therapy for the prevention and treatment of several diseases associated with increased oxidative and inflammatory stress. For example, diabetes is associated with impaired activation of Nrf2, which causes a reduced oxidative-stress defense. Diabetes is also associated with low-grade inflammation. Inflammatory processes and excessive oxidative stress induce insulin resistance, endothelial dysfunction, and diabetic nephropathy. Therefore, pharmacological activation of Nrf2 may potentially improve glucose control and lipid handling as well as micro- and macrocardiovascular disease in diabetics. In addition, the activation of Nrf2 reduces cellular stress and damage in response to xenobiotics, which could be useful for the prevention of cancer. Since excessive production of reactive oxidative species is implicated in neurodegenerative diseases such as multiple sclerosis, Huntington’s and Parkinson’s disease; therefore, the activation of Nrf2 may also provide a potential therapeutic strategy for these diseases. Therefore, targeting Nrf2 may also be useful in treating chronic inflammatory diseases such as chronic obstructive pulmonary disease, arthritis, and sepsis. The modulators of KEAP-1, particularly those with antagonistic activities, such as the compounds of formula (I) described in this patent application can lead to activation of Nrf2 and may potentially provide therapies for the prevention and/or treatment of diabetes, obesity, dyslipidemia, and other related disorders.

Molecular and cellular basis for the unique functioning of Nrf1, an indispensable transcription factor for maintaining cell homoeostasis and organ integrity.

The consensuscis-regulatory AP-1 (activator protein-1)-like AREs (antioxidant-response elements) and/or EpREs (electrophile-response elements) allow for differential recruitment of Nrf1 [NF-E2 (nuclear factor-erythroid 2)-related factor 1], Nrf2 and Nrf3, together with each of their heterodimeric partners (e.g. sMaf, c-Jun, JunD or c-Fos), to regulate different sets of cognate genes. Among them, NF-E2 p45 and Nrf3 are subject to tissue-specific expression in haemopoietic and placental cell lineages respectively. By contrast, Nrf1 and Nrf2 are two important transcription factors expressed ubiquitously in various vertebrate tissues and hence may elicit putative combinational or competitive functions. Nevertheless, they have de facto distinct biological activities because knockout of their genes in mice leads to distinguishable phenotypes. Of note, Nrf2 is dispensable during development and growth, albeit it is accepted as a master regulator of antioxidant, detoxification and cytoprotective genes against cellular stress. Relative to the water-soluble Nrf2, less attention has hitherto been drawn to the membrane-bound Nrf1, even though it has been shown to be indispensable for embryonic development and organ integrity. The biological discrepancy between Nrf1 and Nrf2 is determined by differences in both their primary structures and topovectorial subcellular locations, in which they are subjected to distinct post-translational processing so as to mediate differential expression of ARE-driven cytoprotective genes. In the present review, we focus on the molecular and cellular basis for Nrf1 and its isoforms, which together exert its essential functions for maintaining cellular homoeostasis, normal organ development and growth during life processes. Conversely, dysfunction of Nrf1 results in spontaneous development of non-alcoholic steatohepatitis, hepatoma, diabetes and neurodegenerative diseases in animal models.

Catalase Prevents Maternal Diabetes–Induced Perinatal Programming via the Nrf2–HO-1 Defense System

We investigated whether overexpression of catalase (CAT) in renal proximal tubular cells (RPTCs) could prevent the programming of hypertension and kidney disease in the offspring of dams with maternal diabetes. Male offspring of nondiabetic and diabetic dams from two transgenic (Tg) lines (Hoxb7-green fluorescent protein [GFP]-Tg [controls] and Hoxb7/CAT-GFP-Tg, which overexpress CAT in RPTCs) were studied from the prenatal period into adulthood. Nephrogenesis, systolic blood pressure, renal hyperfiltration, kidney injury, and reactive oxygen species (ROS) generation were assessed. Gene expression of transforming growth factor-β1 (TGF-β1), nuclear factor erythroid 2p45–related factor-2 (Nrf2), and heme oxygenase-1 (HO-1) was tested in both in vitro and in vivo studies. Renal dysmorphogenesis was observed in offspring of Hoxb7-GFP-Tg dams with severe maternal diabetes; the affected male offspring displayed higher renal ROS generation and developed hypertension and renal hyperfiltration as well as renal injury with heightened TGF-β1 expression in adulthood. These changes were ameliorated in male offspring of diabetic Hoxb7/CAT-GFP-Tg dams via the Nrf2–HO-1 defense system. CAT promoted Nrf2 nuclear translocation and HO-1 gene expression, seen in both in vitro and in vivo studies. In conclusion, CAT overexpression in the RPTCs ameliorated maternal diabetes–induced perinatal programming, mediated, at least in part, by triggering the Nrf2–HO-1 defense system.

15-Deoxy-Δ 12,14-prostaglandin J 2 as a potential endogenous regulator of redox-sensitive transcription factors

15-Deoxy-Δ 12,14-prostaglandin J 2 (15d-PGJ 2) has been known to display multifaceted cellular functions, including anti-inflammatory and cytoprotective effects. However, depending on the concentrations and intracellular microenvironment, this cyclopentenone prostaglandin can exert opposite effects. Because of the α,β-unsaturated carbonyl moiety present in its cyclopentenone ring structure, 15d-PGJ 2 can act as a Michael reaction acceptor and readily interacts with critical cellular nucleophiles, such as cysteine thiol groups in proteins. Many of the biological effects induced by 15d-PGJ 2 involve redox-transcription factors as the potential targets. Thus, 15d-PGJ 2 can modulate the transcriptional activities of nuclear factor-κB (NF-κB), activator protein-1 (AP-1), nuclear factor-erythroid 2p45 (NF-E2)-related factors (Nrf2), hypoxia inducible factor (HIF), etc. 15d-PGJ 2 is also well known as an endogenous ligand of peroxisome proliferator-activated receptor γ (PPARγ). However, the regulation of the aforementioned redox-sensitive transcription factors by 15d-PGJ 2 is not necessarily mediated via PPARγ activation, but rather involves covalent modification or oxidation of their critical cysteine residues acting as a redox-sensor. This commentary describes the biological and physiological functions of 15d-PGJ 2 and underlying biochemical and molecular mechanisms with emphasis on the modulation of redox-sensitive transcription factors and their regulators.