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PROVIDER: PRJNA557194 | ENA |
REPOSITORIES: ENA
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Project description:Nrf2 is a transcription factor playing an essential role in stress response. A knowledge of the significance of Nrf2 in cell function has not, as yet, reached out beyond transactivation of gene expression. This paper shows that GDF-15 and SDF-1-induced angiogenesis strongly depends on Nrf2 presence, but is not related to its transcriptional activity. We propose, that Nrf2 serves as a protein restraining Keap1, its known transcriptional repressor. Deficiency of Nrf2 protein available for Keap1 leads to overabundance of RhoGAP1, the protein regulating Cdc42 activity, and impairs podosome assembly, thereby indisposing actin rearrangements, preventing migration and angiogenesis. These activities can be rescued by concomitant deletion of RhoGAP1 or Keap1. We suggest that a new Nrf2 function of a Keap1 scavenger implies revising the established murine model of Nrf2 deficiency as a transcriptional knock out (tKO) mouse. The N-terminal fragment of Nrf2, containing Neh2 domain binding Keap1, is present in these animals. Thus, regarding the function of Nrf2 as a protein sequestering Keap1, both published and unpublished data on Nrf2-Keap1 duet may gain new interpretation.
2018-11-28 | PXD009161 | Pride
Project description:Nrf2 is a transcription factor playing an essential role in stress response. A knowledge of the significance of Nrf2 in cell function has not, as yet, reached out beyond transactivation of gene expression. This paper shows that GDF-15 and SDF-1-induced angiogenesis strongly depends on Nrf2 presence, but is not related to its transcriptional activity. We propose, that Nrf2 serves as a protein restraining Keap1, its known transcriptional repressor. Deficiency of Nrf2 protein available for Keap1 leads to overabundance of RhoGAP1, the protein regulating Cdc42 activity, and impairs podosome assembly, thereby indisposing actin rearrangements, and preventing angiogenesis. These activities can be rescued by concomitant deletion of RhoGAP1 or Keap1. We suggest that a new Nrf2 function of a Keap1 scavenger implies revising the established murine model of Nrf2 deficiency as a transcriptional knock out (tKO) mouse. The N-terminal fragment of Nrf2, containing Neh2 domain binding Keap1, is present in these animals. Thus, regarding the function of Nrf2 as a protein sequestering Keap1, both published and unpublished data on Nrf2-Keap1 duet may gain new interpretation.
2019-01-17 | GSE109312 | GEO
Project description:Transcription factor nuclear factor erythroid 2 p45-related factor 2 (Nrf2) and its main negative regulator, Kelch-like ECH associated protein 1 (Keap1), are at the interface between redox and intermediary metabolism, allowing adaptation and survival under conditions of oxidative, inflammatory and metabolic stress. Nrf2 is the principal determinant of redox homeostasis, and contributes to mitochondrial function and integrity, and cellular bioenergetics. Using proteomics and lipidomics, we show that genetic downregulation of Keap1 in mice, and the consequent Nrf2 activation to pharmacologically-relevant levels, leads to upregulation of carboxylesterase 1 (Ces1) and acyl-CoA oxidase 2 (Acox2), decreases triglycerides levels, and alters the lipidome. This is accompanied by downregulation of hepatic ATP-citrate lyase (Acly) and decreased levels of acetyl-CoA, a trigger for autophagy. These findings suggest that downregulation of Keap1 confers features of a fasted metabolic state, which is an important consideration in the drug development of Keap1-targeting pharmacologic Nrf2 activators.
2020-11-11 | PXD021639 | Pride
Project description:Nrf2 (NF-E2-related factor-2) transcription factor regulates oxidative/xenobiotic stress response and also represses inflammation. However, the mechanisms how Nrf2 alleviates inflammation are still unclear. Here, we demonstrate that Nrf2 interferes with lipopolysaccharide-induced transcriptional upregulation of proinflammatory cytokines, including IL-6 and IL-1β. ChIP-seq and ChIP-qPCR analyses revealed that Nrf2 binds to the proximity of these genes in macrophages and inhibits RNA Pol II recruitment. Further, we found that Nrf2-mediated inhibition is independent of the Nrf2 binding motif and reactive oxygen species level. Murine inflammatory models further demonstrated that Nrf2 interferes with IL6 induction and inflammatory phenotypes in vivo. Thus, contrary to the widely accepted view that Nrf2 suppresses inflammation through redox control, we demonstrate here that Nrf2 opposes transcriptional upregulation of proinflammatory cytokine genes. This study identifies Nrf2 as the upstream regulator of cytokine production and establishes a molecular basis for an Nrf2-mediated anti-inflammation approach. Gene expression in BMDMs obtained from wild-type and Keap1-CKO mice. In Keap1-CKO (Keap1 flox/flox::LysM-Cre) BMDMs, Nrf2 transcription factor is activated due to Keap1-deficiency. BMDMs were obtained by a culture of bone marrow cells in the presence of M-CSF for7 days. M1-activated BMDMs were obtained by stimulation with LPS and IFNg for 6 hours, while M2-activated BMDMs were obtained by a stimulation with IL-4 for 6 hours. Two independent BMDM cultures were performed, and each experiment contains samples obtained from one wild-type and one Keap1-CKO mice, respectively.
2016-05-12 | E-GEOD-71263 | biostudies-arrayexpress
Project description:To overcome oxidative, inflammatory, and metabolic stress, cells have evolved networks of cytoprotective proteins controlled by transcription factor nuclear factor erythroid 2 p45-related factor 2 (Nrf2) and its main negative regulator the Kelch-like ECH associated protein 1 (Keap1). Here, we used high-resolution mass-spectrometry to characterize the proteomes of macrophages with altered Nrf2 status. Our analysis revealed significant differences among the genotypes in cellular metabolism and redox homeostasis, which we validated with Seahorse flux and metabolomics, as well as in anti-viral immune pathways, translational regulation and mitosis. Nrf2 disruption significantly affected the proteome following lipopolysaccharide (LPS) stimulation, with alterations in redox, carbohydrate and lipid metabolism, and innate immunity predominantly. Of note, LPS stimulation was found to promote mitochondrial fusion in a process that was dependent on Nrf2. The Keap1 inhibitor, 4-octyl itaconate (4-OI), a derivative of the mitochondrial immunometabolite itaconate, remodeled the inflammatory macrophage proteome, increasing redox and suppressing anti-viral immune effectors in a Nrf2-dependent manner. These data suggest that Nrf2 activation facilitates metabolic reprogramming, mitochondrial adaptation, and finetunes the innate immune response in macrophages.
2021-08-13 | PXD027737 | Pride
Project description:Genetic versus chemoprotective activation of Nrf2 signaling: overlapping yet distinct hepatic gene expression profiles between Keap1 knockout and triterpenoid treated mice; Loss of Nrf2 signaling increases susceptibility to acute toxicity, inflammation, and carcinogenesis in mice due to the inability to mount adaptive responses. By contrast, disruption of Keap1 (a cytoplasmic modifier of Nrf2 turnover) protects against these stresses in mice; although dominant negative mutations in Keap1 have been identified recently in some human cancers. Global characterization of Nrf2 activation is important to exploit this pathway for chemoprevention in healthy, yet at-risk individuals and also to elucidate the consequences of hijacking the pathway in Keap1-mutant human cancers. This analysis also enables a global characterization of the pharmacodynamic action of CDDO-Im at a low dose that is relevant to chemoprevention. Experiment Overall Design: Liver-targeted conditional Keap1-null (CKO) mice provide a model of genetic activation of Nrf2 signaling. By coupling global gene expression analysis of CKO mice with analysis of pharmacologic activation using the synthetic oleanane triterpenoid CDDO-Im, we are able to gain insight into pathways affected by Nrf2 activation. CDDO-Im is an extremely potent activator of Nrf2 signaling. CKO mice were used to identify genes modulated by genetic activation of Nrf2 signaling. The CKO response was compared to hepatic global gene expression changes in wild-type mice treated with CDDO-Im at a maximal Nrf2 activating dose. n=3/group, male 9 week old mice were used. Mice were treated with a single dose of vehicle (10% Cremophor-EL, 10% DMSO, and PBS) or 30 umol CDDO-Im/kg body weight by gavage and sacrificed 6 h later.
2009-05-11 | E-GEOD-15633 | biostudies-arrayexpress
Project description:Keap1 overexpressed and Nrf2 depleted CL1-5 cells were used to identify genes regulated by Keap1/Nrf2 axis-dependent gene regulations We used microarrays to detail the global programme of gene expression underlying metastasis and identified distinct classes of Keap1/Nrf2-regulated genes during this process. CL1-5 cells stably expressed Keap1 expressing construct and Nrf2-specific shRNA were analyzed compared to control cells
2015-03-04 | E-GEOD-66473 | biostudies-arrayexpress
Project description:Stresses that target mitochondrial function lead to altered transcriptional responses for 100-1000s of genes genome wide, and are signalled via retrograde communication pathways within the cell. rao2 mutants contain a mutation in the NAC family transcription factor ANAC017 and cannot induce stress responsive genes (such as the mitochondrial alternative oxidase 1a) in response to mitochondrial dysfunction. We sought to define the global gene network regulated through RAO2 function in response to mitochondrial stress (mimicked through treatment of plants with antimycin A - a specific inhibitor of complex III in the mitochondrial electron transfer chain), and non-specific stress signals such as hydrogen peroxide. We have defined global stress responses that are positively and negatively mediated by RAO2 function, and show that greater than 80% of transcripts that are differentially regulated under H2O2 stress require proper functioning of ANAC017 for a normal stress responses. We used Affymetrix microarray to characterise global gene expression profiles for mutant plants with compromised mitochondrial retrograde signalling (rao2 mutants), to define the genome wide transcriptional network regulated through RAO1 function under mitochondrial stress and hydrogen peroxide stress. rao2 EMS lines, independent T-DNA knock-out lines for ANAC017 (anac017-1), ANAC017 gain of function mutants (anac017-2) and wild type seedlings were grown for 14 days, the optimal stage as defined by forward genetic screens that identifed rao2 mutants. Seedlings were grown on GamborgB5 plates and treated by spraying plants with 50 µM antimycin A (an elicitor of mitochondrial retrograde signalling) or 20mM hydrogen peroxide while mock control samples were sprayed with deionised water. Samples were collected after 3hr of treatment for global expression profiling.
2013-01-30 | E-GEOD-41136 | biostudies-arrayexpress
Project description:Multiple cancers regulate oxidative stress by activating the transcription factor NRF2 through mutation of its negative regulator KEAP1. NRF2 has been studied extensively in KEAP1-mutant cancers, however the role of this pathway in cancers with wildtype KEAP1 remains poorly understood. To answer this question, we induced NRF2 via pharmacological inactivation of KEAP1 in a panel of 50+ non-small cell lung cancer cell lines. Unexpectedly, marked decreases in viability were observed in >13% of the cell lines—an effect that was rescued by NRF2 ablation. Genome-wide and targeted CRISPR screens revealed that NRF2 induces NADH-reductive stress, through the upregulation of the NAD+-consuming enzyme ALDH3A1. Leveraging these findings, we show that cells treated with KEAP1 inhibitors or those with endogenous KEAP1 mutations are selectively vulnerable to Complex I inhibition, which impairs NADH oxidation capacity and potentiates reductive stress. Thus, we identify reductive stress as a metabolic vulnerability in NRF2-activated lung cancers.
2024-05-24 | PXD039027 | Pride
Project description:Cancer-derived loss-of-function mutations in the KEAP1 tumor suppressor gene stabilize the NRF2 transcription factor, resulting in a pro-survival gene expression program that alters cellular metabolism and neutralizes oxidative stress. In a previous study of KEAP1 mutations observed in lung cancer, we classified 40% of the mutations as ‘superbinders’ (superbinders). These mutants bind and ubiquitylate NRF2 but do not promote NRF2 degradation. Here, we further investigated the molecular mechanism(s) driving the superbinder phenotype. BioID-based quantitative proteomic analysis of the R320Q and R470C superbinder mutations revealed increased co-complexed NRF2 without significant alteration to other KEAP1-associated proteins, including CUL3, VCP, and several ubiquitin receptors within the proteasome lid. Dynamic simulation modeling and limited proteolysis analyses suggest that superbinder mutations stabilize residues in KEAP1 that contact NRF2. In cells, KEAP1 R320Q and R470C mutants co-localize with NRF2, p62/SQSTM1 and polyubiquitin in spherical clusters that rapidly fuse and dissolve; KEAP1-NRF2 localization to these clusters requires p62. Expression of R320Q and R470C in lung cancer cells provided resistance to the reactive oxygen species-inducing drug bleomycin. We present a model wherein superbinder mutations alter the conformational dynamics of the KEAP1-NRF2 complex to alter the cycling of KEAP1 between open and closed conformations, thus inhibiting NRF2 degradation.
2018-11-07 | PXD008411 | Pride