RESUMO
Infections disturb metabolic homeostasis in many contexts, but the underlying connections are not completely understood. To address this, we use paired genetic and computational screens in Drosophila to identify transcriptional regulators of immunity and pathology and their associated target genes and physiologies. We show that Mef2 is required in the fat body for anabolic function and the immune response. Using genetic and biochemical approaches, we find that MEF2 is phosphorylated at a conserved site in healthy flies and promotes expression of lipogenic and glycogenic enzymes. Upon infection, this phosphorylation is lost, and the activity of MEF2 changes--MEF2 now associates with the TATA binding protein to bind a distinct TATA box sequence and promote antimicrobial peptide expression. The loss of phosphorylated MEF2 contributes to loss of anabolic enzyme expression in Gram-negative bacterial infection. MEF2 is thus a critical transcriptional switch in the adult fat body between metabolism and immunity.
Assuntos
Proteínas de Drosophila/metabolismo , Drosophila melanogaster/imunologia , Drosophila melanogaster/metabolismo , Fatores de Regulação Miogênica/metabolismo , Sequência de Aminoácidos , Animais , Candida albicans , Proteínas de Drosophila/imunologia , Drosophila melanogaster/microbiologia , Enterobacter cloacae , Corpo Adiposo/metabolismo , Regulação da Expressão Gênica , Glicogênio/metabolismo , Metabolismo , Mycobacterium marinum , Fatores de Regulação Miogênica/imunologia , Fosforilação , Proteína de Ligação a TATA-Box/metabolismoRESUMO
The human body is continuously exposed to xenobiotics and internal or external oxidants. The health risk assessment of exogenous chemicals remains a complex and challenging issue. Alternative toxicological test methods have become an essential strategy for health risk assessment. As a core regulator of constitutive and inducible expression of antioxidant response element (ARE)-dependent genes, nuclear factor erythroid 2-related factor 2 (Nrf2) plays a critical role in maintaining cellular redox homeostasis. Consistent with the properties of Nrf2-mediated antioxidant response, Nrf2-ARE activity is a direct indicator of oxidative stress and thus has been used to identify and characterize oxidative stressors and redox modulators. To screen and distinguish chemicals or environmental insults that affect the cellular antioxidant activity and/or induce oxidative stress, various in vitro cell models expressing distinct ARE reporters with high-throughput and high-content properties have been developed. These ARE-reporter systems are currently widely applied in drug discovery and safety assessment. In the present review, we provide an overview of the basic structures and applications of various ARE-reporter systems employed for discovering Nrf2-ARE modulators and characterizing oxidative stressors.
Assuntos
Elementos de Resposta Antioxidante , Fator 2 Relacionado a NF-E2 , Antioxidantes/farmacologia , Descoberta de Drogas , Humanos , Fator 2 Relacionado a NF-E2/genética , Fator 2 Relacionado a NF-E2/metabolismo , Oxidantes , Estresse Oxidativo , Xenobióticos/toxicidadeRESUMO
Arsenic is a notorious environmental pollutant. Of note, developmental arsenic exposure has been found to increase the risk of developing a variety of ailments later in life, but the underlying mechanism is not well understood. Many elements of host health have been connected to the gut microbiota. It is still unclear whether and how developmental arsenic exposure affects the gut microbiota. In the present study, we found that developmental arsenic exposure changed intestinal morphology and increased intestinal permeability and inflammation in mouse pups at weaning. These alterations were accompanied by a significant change in gut microbiota, as evidenced by considerably reduced gut microbial richness and diversity. In developmentally arsenic-exposed pups, the relative abundance of Muribaculaceae was significantly decreased, while the relative abundance of Akkermansia and Bacteroides was significantly enhanced at the genus level. Metabolome and pathway enrichment analyses indicated that amino acid and purine metabolism was promoted, while glycerophospholipid metabolism was inhibited. Interestingly, the relative abundance of Muribaculaceae and Akkermansia showed a strong correlation with most plasma metabolites significantly altered by developmental arsenic exposure. These data indicate that gut microbiota dysbiosis may be a critical link between developmental arsenic exposure and metabolic disorders and shed light on the mechanisms underlying increased susceptibility to diseases due to developmental arsenic exposure.
Assuntos
Arsênio , Microbioma Gastrointestinal , Animais , Arsênio/toxicidade , Disbiose/induzido quimicamente , Metabolismo dos Lipídeos , Metaboloma , CamundongosRESUMO
Alcoholic liver disease (ALD) is a major cause of morbidity and mortality from liver disorders. Various mechanisms, including oxidative stress and impaired lipid metabolism, have been implicated in the pathogenesis of ALD. Our previous studies showed that nuclear factor erythroid-derived 2-like 2 (Nrf2) is a master regulator of adaptive antioxidant response and lipid metabolism by using a liver-specific Nrf2 knockout (Nrf2(L)-KO) mouse model. In the current study, an ALD model was developed by a Lieber-DeCarli liquid-based ethanol diet given to this Nrf2(L)-KO mouse strain. We found that Nrf2(L)-KO mice were quite sensitive to lethality from 6.3% ethanol diet. We thus decreased the ethanol concentration to 4.2% to obtain tissues to analyze the role of hepatic Nrf2 in the development of ALD. We found that mild hepatic steatosis occurred with both liquid control and 4.2% ethanol diet feeding, which contain 35% fat. Both the fatty acid ß-oxidation marker peroxisome proliferators-activated receptor α (PPARα), and lipogenesis regulator PPARγ were reduced with ethanol feeding in Nrf2(L)-KO mice, compared to Nrf2 floxed control mice (Nrf2-LoxP). However, Nrf2(L)-KO livers showed more cell injury than the livers of Nrf2-LoxP mice. Consistent with these data, there was increased proportion of apoptotic cells in the liver of ethanol-fed Nrf2(L)-KO mice comparing Nrf2-LoxP controls. Mechanistically, Nrf2 mediated expression of ethanol detoxification enzymes, such as alcohol dehydrogenase 1 and aldehyde dehydrogenase1a1, likely contributed to the sensitivity to ethanol toxicity. In conclusion, hepatic Nrf2 is critical to the development of ALD, particularly the morbidity and liver injury.
Assuntos
Hepatopatias Alcoólicas , Fator 2 Relacionado a NF-E2/deficiência , Álcool Desidrogenase/genética , Animais , Catalase/genética , Etanol , Metabolismo dos Lipídeos/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/metabolismo , Fígado/patologia , Hepatopatias Alcoólicas/genética , Hepatopatias Alcoólicas/metabolismo , Hepatopatias Alcoólicas/mortalidade , Hepatopatias Alcoólicas/patologia , Masculino , Camundongos Transgênicos , Fator 2 Relacionado a NF-E2/genética , Triglicerídeos/metabolismoRESUMO
Cadmium (Cd) is a heavy metal pollutant that adversely effects the kidney. Oxidative stress and inflammation are likely major mechanisms of Cd-induced kidney injury. Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is crucial in regulating antioxidant and inflammatory responses. To investigate the role of Nrf2 in the development of subacute Cd-induced renal injury, we utilized Nrf2 knockout (Nrf2-KO) and control mice (Nrf2-WT) which were given cadmium chloride (CdCl2, 1 or 2 mg/kg i.p.) once daily for 7 days. While subacute CdCl2 exposure induced kidney injury in a dose-dependent manner, after the higher Cd dosage exposure, Nrf2-KO mice showed elevated blood urea nitrogen (BUN) and urinary neutrophil gelatinase-associated lipocalin (NGAL) levels compared to control. In line with the findings, the renal tubule injury caused by 2 mg Cd/kg, but not lower dosage, in Nrf2-KO mice determined by Periodic acid-Schiff staining was more serious than that in control mice. Further mechanistic studies showed that Nrf2-KO mice had more apoptotic cells and severe oxidative stress and inflammation in the renal tubules in response to Cd exposures. Although there were no significant differences in Cd contents of tissues between Cd-exposed Nrf2-WT and Nrf2-KO mice, the mRNA expression of Nrf2 downstream genes, including heme oxygenase 1 and metallothionein 1, were significantly less induced by Cd exposures in the kidney of Nrf2-KO compared with Nrf2-WT mice. In conclusion, Nrf2-deficient mice are more sensitive to kidney injury induced by subacute Cd exposure due to a muted antioxidant response, as well as a likely diminished production of specific Cd detoxification metallothioneins.
Assuntos
Cloreto de Cádmio/toxicidade , Nefropatias/induzido quimicamente , Fator 2 Relacionado a NF-E2/genética , Estresse Oxidativo/efeitos dos fármacos , Animais , Antioxidantes/metabolismo , Apoptose/efeitos dos fármacos , Cloreto de Cádmio/administração & dosagem , Relação Dose-Resposta a Droga , Feminino , Inflamação/induzido quimicamente , Inflamação/patologia , Nefropatias/genética , Testes de Função Renal , Metalotioneína/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos KnockoutRESUMO
Focal segmental glomerulosclerosis (FSGS) is the most common cause of adult nephrotic syndrome in USA. Its mechanisms remain unclear and the effective treatment lacks. We previously reported that upregulation of microRNA (miR)-150 in human podocytes increases profibrotic proteins and decreases anti-fibrotic suppressor of cytokine signaling 1 (SOCS1). We aimed to clarify whether miR-150 inhibitor can ameliorate glomerular injury and to identify its corresponding mechanisms in adriamycin-induced FSGS mice. We found that renal miR-150 increased in adriamycin-induced FSGS mice and FAM-labeled locked nucleic acid-anti-miR-150 (LNA-anti-miR-150) was absorbed by the animal kidneys 6 h after subcutaneous injection. The administration of LNA-anti-miR-150 (2 mg/kg BW twice weekly for 6 w) inhibited renal miR-150 levels without systemic toxicity. With renal miR-150 inhibition, proteinuria, hypoalbuminemia, and hyperlipemia were ameliorated in FSGS mice compared to the scrambled LNA. Meanwhile, the elevated profibrotic proteins and proinflammatory cytokines, decreased antifibrotic SOCS1, and the filtration of T cells in FSGS mice were reverted by LNA-anti-miR-150. Finally, we found that miR-150 most located on podocytes in renal biopsies of FSGS patients. We conclude that LNA-anti-miR-150 might be a novel promising therapeutic agent for FSGS. The renal protective mechanisms might be mediated by anti-fibrosis and anti-inflammation as well as reducing infiltration of T cells in the kidney.
Assuntos
Glomerulosclerose Segmentar e Focal/terapia , MicroRNAs/antagonistas & inibidores , Oligonucleotídeos/uso terapêutico , Animais , Doxorrubicina/efeitos adversos , Fibrose , Terapia Genética , Glomerulosclerose Segmentar e Focal/induzido quimicamente , Glomerulosclerose Segmentar e Focal/genética , Glomerulosclerose Segmentar e Focal/patologia , Humanos , Rim/metabolismo , Rim/patologia , Camundongos , Camundongos Endogâmicos BALB C , MicroRNAs/genéticaRESUMO
As a set of distinct syndromes, focal segmental glomerulosclerosis (FSGS) is the most common cause of adult nephrotic syndrome with diverse mechanisms. We recently found that expression of the circular RNA circZNF609 is increased in renal biopsies of lupus nephritis patients. In the present study, we aimed to determine whether circZNF609 participates in the pathogenesis of FSGS in mice given Adriamycin. In FSGS mice, circZNF609 was upregulated while miR-615-5p was downregulated in FSGS mice analyzed by qPCR and fluorescence in situ hybridization (FISH). Expression of podocyte proteins Wilms tumor 1 (WT1) and podocin were decreased, while expression of collagen 1 (COL1) and transforming growth factor-beta1 (TGF-ß1) were increased on Western blotting. Renal circZNF609 levels were positively correlated and miR-615-5p levels were negatively correlated with the degree of podocyte injury and renal fibrosis. Importantly, circZNF609 and miR-615-5p co-localized to glomeruli and tubules on FISH. Perfect match seeds were found between circZNF609 and miR-615-5p and COL1 mRNA, leading us to explore mechanisms of circZNF609 in bovine serum albumin (BSA) stimulating HK-2 cells, which model the toxicity of proteinuria on tubular cells. In vitro studies, circZNF609 increased and miR-615-5p decreased after BSA treatment and were negatively correlated with each other. COL1 and TGF-ß1 were both upregulated and negatively correlated with miR-615-5p. Lastly, circZNF609 expression increased in glomeruli and tubules of FSGS patient renal biopsies. We conclude that circZNF609 may play an important role in FSGS by sponging miR-615-5p.
Assuntos
Glomerulosclerose Segmentar e Focal/genética , MicroRNAs/metabolismo , RNA Circular/metabolismo , Animais , Sequência de Bases , Linhagem Celular , Doxorrubicina , Fibrose , Regulação da Expressão Gênica , Glomerulosclerose Segmentar e Focal/patologia , Humanos , Rim/metabolismo , Rim/patologia , Masculino , Camundongos Endogâmicos BALB C , MicroRNAs/genética , Podócitos/metabolismo , Podócitos/patologia , RNA Circular/genética , Soroalbumina BovinaRESUMO
Arsenic exposure increases the risk of various bone disorders. For instance, chronic exposure to low level arsenic can cause bone resorption by promoting osteoclast differentiation. Osteoclast precursor cells produce hydrogen peroxide after low level arsenic exposure and then undergo differentiation, producing cells which break down bone matrix. Nuclear factor E2-related factor 2 (Nrf2) regulates receptor activator of nuclear factor-κB dependent osteoclastogenesis by modulating intracellular reactive oxygen species (ROS) signaling via expression of cytoprotective enzymes. Here we tested the hypothesis that loss of Nrf2 will increase arsenic-induced bone loss. We treated 40â¯week-old Nrf2+/+ and Nrf2-/- mice with 5â¯ppm arsenic in the drinking water, which produces a blood arsenic level similar to humans living in areas where arsenic exposure is endemic. After 4â¯months, Micro-CT and dual-energy x-ray analysis revealed a drastic overall decrease in the bone volume with arsenic treatment in mice lacking Nrf2. Deficiency of Nrf2 in RAW 264.7 cells or bone marrow-derived macrophages (BMMs) promoted arsenic-induced osteoclast differentiation. Lack of Nrf2 increases arsenic-induced ROS levels and phosphorylation of p38. N-Acetyl-cysteine and SB203580 pretreatment essentially abolished arsenic-induced phosphorylation of p38 and reversed arsenic-induced increased osteoclast differentiation in Nrf2 deficiency. Taken together, our data suggest that loss of Nrf2 causes increased oxidative stress and enhanced susceptibility to arsenic-induced bone loss.
Assuntos
Arsenitos/toxicidade , Remodelação Óssea/efeitos dos fármacos , Fêmur/efeitos dos fármacos , Fator 2 Relacionado a NF-E2/deficiência , Osteoclastos/efeitos dos fármacos , Osteogênese/efeitos dos fármacos , Osteoporose/induzido quimicamente , Compostos de Sódio/toxicidade , Animais , Feminino , Fêmur/metabolismo , Fêmur/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fator 2 Relacionado a NF-E2/genética , Osteoclastos/metabolismo , Osteoclastos/patologia , Osteoporose/genética , Osteoporose/metabolismo , Osteoporose/patologia , Estresse Oxidativo/efeitos dos fármacos , Células RAW 264.7 , Transdução de Sinais/efeitos dos fármacosRESUMO
The maintenance of healthy adipose tissues is essential for efficient regulation of energy homeostasis. Nuclear factor-erythroid 2-related factor 1 (NFE2L1, also known as Nrf1), a CNC-bZIP protein, is a master regulator of the cellular adaptive response to stresses. To investigate the role of NFE2L1 in adipocytes, we bred a line of mice with adipocyte-specific Nfe2l1 knockout (Nfe2l1(f)-KO), and found that Nfe2l1(f)-KO mice exhibited a dramatically reduced subcutaneous adipose tissue (SAT) mass, insulin resistance, adipocyte hypertrophy, and severe adipose inflammation. Mechanistic studies revealed that Nfe2l1 deficiency may disturb the expression of lipolytic genes in adipocytes, leading to adipocyte hypertrophy followed by inflammation, pyroptosis, and insulin resistance. Our findings reveal a novel role for NFE2L1 in regulating adipose tissue plasticity and energy homeostasis.
Assuntos
Adipócitos/patologia , Tecido Adiposo Branco/patologia , Inflamação/patologia , Lipólise , Fator 1 Relacionado a NF-E2/genética , Adipócitos/metabolismo , Tecido Adiposo Branco/citologia , Tecido Adiposo Branco/metabolismo , Adiposidade , Animais , Distribuição da Gordura Corporal , Metabolismo Energético , Regulação da Expressão Gênica , Hipertrofia , Inflamação/genética , Inflamação/metabolismo , Resistência à Insulina , Masculino , Camundongos , Camundongos KnockoutRESUMO
Non-small cell lung cancer (NSCLC) has a high mortality rate worldwide. Various treatments strategies have been used against NSCLC including individualized chemotherapies, but innate or acquired cancer cell drug resistance remains a major obstacle. Recent studies revealed that the Kelch-like ECH associated protein 1/Nuclear factor erythroid 2-related factor 2 (Keap1/Nrf2) pathway is intimately involved in cancer progression and chemoresistance. Thus, antagonizing Nrf2 would seem to be a viable strategy in cancer therapy. In the present study a traditional Chinese medicine, triptolide, was identified that markedly inhibited expression and transcriptional activity of Nrf2 in various cancer cells, including NSCLC and liver cancer cells. Consequently, triptolide made cancer cells more chemosensitivity toward antitumor drugs both in vitro and in a xenograft tumor model system using lung carcinoma cells. These results suggest that triptolide blocks chemoresistance in cancer cells by targeting the Nrf2 pathway. Triptolide should be further investigated in clinical cancer trials.
Assuntos
Antineoplásicos Alquilantes/administração & dosagem , Elementos de Resposta Antioxidante/efeitos dos fármacos , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Diterpenos/administração & dosagem , Neoplasias Pulmonares/tratamento farmacológico , Fator 2 Relacionado a NF-E2/antagonistas & inibidores , Fenantrenos/administração & dosagem , Células A549 , Animais , Antineoplásicos/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Elementos de Resposta Antioxidante/fisiologia , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Carcinoma Pulmonar de Células não Pequenas/patologia , Relação Dose-Resposta a Droga , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/fisiologia , Compostos de Epóxi/administração & dosagem , Células Hep G2 , Humanos , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Fator 2 Relacionado a NF-E2/metabolismo , Resultado do Tratamento , Carga Tumoral/efeitos dos fármacos , Carga Tumoral/fisiologia , Ensaios Antitumorais Modelo de Xenoenxerto/métodosRESUMO
Hypoxia is a key pathological process involved in many cutaneous diseases. Nuclear factor E2-related factor 2 (NRF2) is a central regulator of antioxidant response element (ARE)-dependent transcription and plays a pivotal role in the cellular adaptive response to oxidative stress. Kelch-like ECH-associated protein 1 (KEAP1) is a cullin-3-adapter protein that represses the activity of NRF2 by mediating its ubiquitination and degradation. In the present study, we examined the role of NRF2 signaling pathway in the cytotoxicity induced by cobalt chloride(CoCl2), a hypoxia-mimicking agent, in human keratinocyte HaCaT cells with stable knockdown of NRF2 (NRF2-KD) and KEAP1 (KEAP1-KD). Acute CoCl2 exposure markedly increased the levels of intracellular reactive oxygen species (ROS), and resulted in hypoxic damage and cytotoxicity of HaCaT cells. Stable knockdown of NRF2 dramatically reduced the expression of many antioxidant enzymes and sensitized the cells to acute CoCl2-induced oxidative stress and cytotoxicity. In contrast, KEAP1-KD cells observably enhanced the activity of NRF2 and ARE-regulated genes and led to a significant resistance to CoCl2-induced cellular damage. In addition, pretreatment of HaCaT cells with tert-butylhydroquinone, a well-known NRF2 activator, protected HaCaT cells from CoCl2-induced cellular injury in a NRF2-dependent fashion. Likewise, physical hypoxia-induced cytotoxicity could be significantly ameliorated through NRF2 signaling pathway in HaCaT cells. Together, our results suggest that NRF2 signaling pathway is involved in antioxidant response triggered by CoCl2-induced oxidative stress and could protect human keratinocytes against acute CoCl2 -induced hypoxic cytotoxicity.
Assuntos
Hipóxia Celular/efeitos dos fármacos , Cobalto/toxicidade , Queratinócitos/efeitos dos fármacos , Fator 2 Relacionado a NF-E2/metabolismo , Transdução de Sinais/efeitos dos fármacos , Elementos de Resposta Antioxidante/efeitos dos fármacos , Antioxidantes/metabolismo , Apoptose/efeitos dos fármacos , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Técnicas de Silenciamento de Genes , Humanos , Hidroquinonas/toxicidade , Fator 2 Relacionado a NF-E2/genética , Estresse Oxidativo/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/genéticaRESUMO
Alcoholic liver disease (ALD) is a leading cause of morbidity and mortality of liver disorders and a major health issue globally. ALD refers to a spectrum of liver pathologies ranging from steatosis, steatohepatitis, fibrosis, cirrhosis and even hepatocellular carcinoma. Various mechanisms, including oxidative stress, protein and DNA modification, inflammation and impaired lipid metabolism, have been implicated in the pathogenesis of ALD. Further, reactive oxygen species (ROS) in particular, have been identified as a key component in the initiation and progression of ALD. Nuclear factor erythroid 2 like 2 (Nrf2) is a master regulator of the intracellular adaptive antioxidant response to oxidative stress, and aids in the detoxification of a variety of toxicants. Given its cytoprotective role, Nrf2 has been extensively studied as a therapeutic target for ALD. Paradoxically, however, emerging evidence have revealed that Nrf2 may be implicated in the progression of ALD. In this review, we summarize the role of Nrf2 in the development of ALD and discuss the underlying mechanisms. Clearly, more comprehensive studies with proper animal and cell models and in human are needed to verify the potential therapeutic role of Nrf2 in ALD.
Assuntos
Hepatopatias Alcoólicas/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Regulação da Expressão Gênica , Humanos , Fator 2 Relacionado a NF-E2/genética , Estresse Oxidativo , Espécies Reativas de OxigênioRESUMO
Traumatic brain injury (TBI), which leads to high mortality and morbidity, is a prominent public health problem worldwide with no effective treatment. Curcumin has been shown to be beneficial for neuroprotection in vivo and in vitro, but the underlying mechanism remains unclear. This study determined whether the neuroprotective role of curcumin in mouse TBI is dependent on the NF-E2-related factor (Nrf2) pathway. The Feeney weight-drop contusion model was used to mimic TBI. Curcumin was administered intraperitoneally 15â¯min after TBI induction, and brains were collected at 24â¯h after TBI. The levels of Nrf2 and its downstream genes (Hmox-1, Nqo1, Gclm, and Gclc) were detected by Western blot and qRT-PCR at 24â¯h after TBI. In addition, edema, oxidative damage, cell apoptosis and inflammatory reactions were evaluated in wild type (WT) and Nrf2-knockout (Nrf2-KO) mice to explore the role of Nrf2 signaling after curcumin treatment. In wild type mice, curcumin treatment resulted in reduced ipsilateral cortex injury, neutrophil infiltration, and microglia activation, improving neuron survival against TBI-induced apoptosis and degeneration. These effects were accompanied by increased expression and nuclear translocation of Nrf2, and enhanced expression of antioxidant enzymes. However, Nrf2 deletion attenuated the neuroprotective effects of curcumin in Nrf2-KO mice after TBI. These findings demonstrated that curcumin effects on TBI are associated with the activation the Nrf2 pathway, providing novel insights into the neuroprotective role of Nrf2 and the potential therapeutic use of curcumin for TBI.
Assuntos
Lesões Encefálicas Traumáticas/tratamento farmacológico , Curcumina/farmacologia , Fator 2 Relacionado a NF-E2/metabolismo , Fármacos Neuroprotetores/farmacologia , Transdução de Sinais/efeitos dos fármacos , Animais , Antioxidantes/metabolismo , Apoptose/efeitos dos fármacos , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Lesões Encefálicas Traumáticas/metabolismo , Modelos Animais de Doenças , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Estresse Oxidativo/efeitos dos fármacosRESUMO
Background: Nuclear factor erythroid 2-related factor 2 (Nrf2) is a central mediator of cellular responses to oxidative stress. We hypothesized that Nrf2 modulates progression from acute tubular damage to renal fibrosis. We asked whether Nrf2 deletion increases renal injury in mice following unilateral ureteral obstruction (UUO). Methods: We explored the time course of renal injury and Nrf2 expression in Nrf2+/+ mice following UUO. We compared Nrf2+/+ and Nrf2-/- mice following UUO in tubular damage, transdifferentiation [vimentin, proliferating cell nuclear antigen (PCNA)], fibrosis [fibronectin, α-smooth muscle actin (SMA)], antioxidative and inflammatory responses. We studied Nrf2 in renal biopsies of patients with acute, subacute and chronic tubulointerstitial nephritis (TIN). Results: In Nrf2+/+ mice, renal Nrf2 expression and Nrf2-regulated glutamate-cysteine ligase catalytic (Gclc) and heme oxygenase-1 (Ho-1) were elevated, and renal injury occurred between 2 and 14 days after UUO. On Day 2 following UUO, in Nrf2-/- mice compared with Nrf2+/+ mice, tubular damage, apoptotic cell numbers, cleaved caspase3 and cleaved-poly ADP-ribose polymerase were increased. On Day 5, protein levels of vimentin and PCNA and the co-expressed cells of both proteins were increased. On Day 14, fibronectin and α-SMA protein levels were increased. Nrf2 deletion decreased expression of antioxidative genes (Gclc and Ho-1) and increased expression of inflammatory response genes (Tgfß, Tnf, IL-6, IL-1ß and F4/80). Finally, Nrf2 expression was upregulated in renal biopsies of patients with TIN. Conclusions: Following UUO, Nrf2 deficiency increased tubular damage, transdifferentiation, fibrosis and inflammatory response while decreasing antioxidative responses. The renal protective role of Nrf2 in the development of tubulointerstitial fibrosis in UUO may be mediated by antioxidative and anti-inflammatory pathways.
Assuntos
Fibrose/patologia , Fator 2 Relacionado a NF-E2/metabolismo , Fator 2 Relacionado a NF-E2/fisiologia , Nefrite Intersticial/patologia , Obstrução Ureteral/complicações , Adulto , Animais , Progressão da Doença , Feminino , Fibrose/etiologia , Fibrose/metabolismo , Humanos , Masculino , Camundongos , Camundongos Knockout , Pessoa de Meia-Idade , Nefrite Intersticial/etiologia , Nefrite Intersticial/metabolismo , Estresse OxidativoRESUMO
Increasing evidence indicates that chronic inorganic arsenic exposure is associated with type 2 diabetes (T2D), a disease of growing prevalence. Pancreatic ß-cells were targeted and damaged by oxidative stress induced by arsenite. We previously showed that nuclear factor erythroid 2 like 2 (Nfe2l2)-deficient pancreatic ß-cells were vulnerable to cell damage induced by oxidative stressors including arsenite, due to a muted antioxidant response. Like nuclear factor erythroid 2 like 2 (NFE2L2), NFE2L1 also belongs to the cap 'n' collar (CNC) basic-region leucine zipper (bZIP) transcription factor family, and regulates antioxidant response element (ARE) related genes. Our prior work showed NFE2L1 regulates glucose-stimulated insulin secretion (GSIS) in pancreatic ß-cells and isolated islets. In the current study, we demonstrated that MIN6 cells with a specific knockdown of long isoforms of Nfe2l1 (L-Nfe2l1) by lentiviral shRNA (Nfe2l1(L)-KD) were vulnerable to arsenite-induced apoptosis and cell damage. The expression levels of antioxidant genes, such as Gclc, Gclm and Ho-1, and intracellular reactive oxygen species (ROS) levels were not different in Scramble and Nfe2l1(L)-KD cells, while the expression of arsenic metabolism related-genes, such as Gsto1, Gstm1 and Nqo1, increased in Nfe2l1(L)-KD cells with or without arsenite treatment. The up-regulation of arsenic biotransformation genes was due to activated NFE2L2 in Nfe2l1(L)-KD MIN6 cells. Furthermore, the level of intracellular monomethylarsenic (MMA) was higher in Nfe2l1(L)-KD MIN6 cells than in Scramble cells. These results showed that deficiency of L-Nfe2l1 in pancreatic ß-cells increased susceptibility to acute arsenite-induced cytotoxicity by promoting arsenic biotransformation and intracellular MMA levels.
Assuntos
Arsenitos/toxicidade , Células Secretoras de Insulina/efeitos dos fármacos , Fator 1 Relacionado a NF-E2/deficiência , Compostos de Sódio/toxicidade , Animais , Arsenitos/metabolismo , Biotransformação/genética , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Regulação Enzimológica da Expressão Gênica , Células Secretoras de Insulina/enzimologia , Células Secretoras de Insulina/patologia , Metilação , Camundongos , Fator 1 Relacionado a NF-E2/genética , Estresse Oxidativo/efeitos dos fármacos , Isoformas de Proteínas , Interferência de RNA , RNA Mensageiro/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/efeitos dos fármacos , Compostos de Sódio/metabolismo , TransfecçãoRESUMO
Nuclear factor E2-related factor 2 (NRF2) and uncoupling protein 2 (UCP2) are indicated to protect from oxidative stress. They also play roles in the homeostasis of glutathione. However, the detailed mechanisms are not well understood. In the present study, we found Nrf2-knockout (Nrf2-KO) mice exhibited altered glutathione homeostasis and reduced expression of various genes involved in GSH biosynthesis, regeneration, utilization and transport in the liver. Ucp2-knockout (Ucp2-KO) mice exhibited altered glutathione homeostasis in the liver, spleen and blood, as well as increased transcript of cystic fibrosis transmembrane conductance regulator in the liver, a protein capable of mediating glutathione efflux. Nrf2-Ucp2-double knockout (DKO) mice showed characteristics of both Nrf2-KO and Ucp2-KO mice. But no significant difference was observed in DKO mice when compared with Nrf2-KO or Ucp2-KO mice, except in blood glutathione levels. These data suggest that ablation of Nrf2 and Ucp2 leads to disrupted GSH balance, which could result from altered expression of genes involved in GSH metabolism. DKO may not evoke more severe oxidative stress than the single gene knockout.
Assuntos
Glutationa/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Proteína Desacopladora 2/metabolismo , Animais , Regulação da Expressão Gênica , Técnicas de Inativação de Genes , Glutationa/sangue , Glutationa/genética , Fígado/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fator 2 Relacionado a NF-E2/genética , Estresse Oxidativo , Proteína Desacopladora 2/genéticaRESUMO
Cancer cells subvert multiple properties of normal cells, including escaping strict cell cycle regulation, gaining resistance to cell death, and remodeling the tumor microenvironment. The hallmarks of cancer have recently been updated and summarized. Nuclear factor erythroid 2-related factor 1 (NFE2L1, also named NRF1) belongs to the cap'n'collar (CNC) basic-region leucine zipper (bZIP) family. It acts as a transcription factor and is indispensable for maintaining both cellular homoeostasis and organ integrity during development and growth, as well as adaptive responses to pathophysiological stressors. In addition, NFE2L1 mediates the proteasome bounce-back effect in the clinical proteasome inhibitor therapy of neuroblastoma, multiple myeloma, and triple-negative breast cancer, which quickly induces proteasome inhibitor resistance. Recent studies have shown that NFE2L1 mediates cell proliferation and metabolic reprogramming in various cancer cell lines. We combined the framework provided by "hallmarks of cancer" with recent research on NFE2L1 to summarize the role and mechanism of NFE2L1 in cancer. These ongoing efforts aim to contribute to the development of potential novel cancer therapies that target the NFE2L1 pathway and its activity.
RESUMO
BACKGROUND: Cadmium (Cd) is a highly toxic and widespread environmental oxidative stressor that causes a myriad of health problems, including osteoporosis and bone damage. Although nuclear factor erythroid 2-related factor 2 (NRF2) and its Cap 'n' Collar and basic region Leucine Zipper (CNC-bZIP) family member nuclear factor erythroid 2-related factor 1 (NRF1) coordinate various stress responses by regulating the transcription of a variety of antioxidant and cytoprotective genes, they play distinct roles in bone metabolism and remodeling. However, the precise roles of both transcription factors in bone loss induced by prolonged Cd exposure remain unclear. OBJECTIVES: We aimed to understand the molecular mechanisms underlying Cd-induced bone loss, focusing mainly on the roles of NRF2 and NRF1 in osteoclastogenesis provoked by Cd. METHODS: Male wild-type (WT), global Nrf2-knockout (Nrf2-/-) and myeloid-specific Nrf2 knockout [Nrf2(M)-KO] mice were administered Cd (50 or 100 ppm) via drinking water for 8 or 16 wk, followed by micro-computed tomography, histological analyses, and plasma biochemical testing. Osteoclastogenesis was evaluated using bone marrow-derived osteoclast progenitor cells (BM-OPCs) and RAW 264.7 cells in the presence of Cd (10 or 20 nM) with a combination of genetic and chemical modulations targeting NRF2 and NRF1. RESULTS: Compared with relevant control mice, global Nrf2-/- or Nrf2(M)-KO mice showed exacerbated bone loss and augmented osteoclast activity following exposure to 100 ppm Cd in drinking water for up to 16 wk. In vitro osteoclastogenic analyses suggested that Nrf2-deficient BM-OPCs and RAW 264.7 cells responded more robustly to low levels of Cd (up to 20 nM) with regard to osteoclast differentiation compared with WT cells. Further mechanistic studies supported a compensatory up-regulation of long isoform of NRF1 (L-NRF1) and subsequent induction of nuclear factor of activated T cells, cytoplasmic, calcineurin dependent 1 (NFATc1) as the key molecular events in the Nrf2 deficiency-worsened and Cd-provoked osteoclastogenesis. L-Nrf1 silenced (via lentiviral means) Nrf2-knockdown (KD) RAW cells exposed to Cd showed dramatically different NFATc1 and subsequent osteoclastogenesis outcomes compared with the cells of Nrf2-KD alone exposed to Cd, suggesting a mitigating effect of the Nrf1 silencing. In addition, suppression of reactive oxygen species by exogenous antioxidants N-acetyl-l-cysteine (2 mM) and mitoquinone mesylate (MitoQ; 0.2µM) mitigated the L-NRF1-associated effects on NFATc1-driven osteoclastogenesis outcomes in Cd-exposed Nrf2-KD cells. CONCLUSIONS: This in vivo and in vitro study supported the authors' hypothesis that Cd exposure caused bone loss, in which NRF2 and L-NRF1 responded to Cd and osteoclastogenic stimuli in a cooperative, but contradictive, manner to coordinate Nfatc1 expression, osteoclastogenesis and thus bone homeostasis. Our study suggests a novel strategy targeting NRF2 and L-NRF1 to prevent and treat the bone toxicity of Cd. https://doi.org/10.1289/EHP13849.
Assuntos
Cádmio , Fator 2 Relacionado a NF-E2 , Osteoclastos , Osteogênese , Animais , Camundongos , Masculino , Cádmio/toxicidade , Fator 2 Relacionado a NF-E2/metabolismo , Fator 2 Relacionado a NF-E2/genética , Osteoclastos/efeitos dos fármacos , Osteogênese/efeitos dos fármacos , Camundongos Knockout , Fator 1 Relacionado a NF-E2/genética , Fator 1 Relacionado a NF-E2/metabolismo , Camundongos Endogâmicos C57BL , Diferenciação Celular/efeitos dos fármacosRESUMO
PURPOSE: Oxidative stress is implicated in pancreatic ß-cell dysfunction, yet clinical outcomes of antioxidant therapies on diabetes are inconclusive. Since reactive oxygen species (ROS) can function as signaling intermediates for glucose-stimulated insulin secretion (GSIS), we hypothesize that exogenously boosting cellular antioxidant capacity dampens signaling ROS and GSIS. METHODS: To test the hypothesis, we formulated a mathematical model of redox homeostatic control circuit comprising known feedback and feedforward loops and validated model predictions with plant-derived antioxidant sulforaphane (SFN). RESULTS: SFN acutely (30-min treatment) stimulated basal insulin secretion in INS-1(832/13) cells and cultured mouse islets, which could be attributed to SFN-elicited ROS as N-acetylcysteine or glutathione ethyl ester suppressed SFN-stimulated insulin secretion. The mathematical model predicted an adapted redox state characteristic of strong induction of endogenous antioxidants but marginally increased ROS under prolonged SFN exposure, a state that attenuates rather than facilitates glucose-stimulated ROS and GSIS. We validated the prediction by demonstrating that although 24-h treatment of INS-1(832/13) cells with low, non-cytotoxic concentrations of SFN (2-10 µM) protected the cells from cytotoxicity by oxidative insult, it markedly suppressed insulin secretion stimulated by 20 mM glucose. CONCLUSIONS: Our study indicates that adaptive induction of endogenous antioxidants by exogenous antioxidants, albeit cytoprotective, inhibits GSIS in ß-cells.