Project description:Functional analysis of the cytoprotective transcription factor Nrf2 in skin morphogenesis and disease: Identification of Nrf2 target genes
Project description:The Nrf2 transcription factor is a key player in the cellular stress response, which regulates the expression of important antioxidant enzymes and other cytoprotective proteins. We recently generated a novel transgenic mouse model to determine the function of Nrf2 in the skin. These mice show reduced number of apoptotic keratinocytes after UVB irradiation due to enhanced ROS detoxification. They also show enhanced tumorigenesis in the HPV8 tumor model. RNA from whole skin of 3 single P2.5 K5cre-caNrf2 (tg/tg) and 3 single P2.5 K5cre-wt (tg/wt=control) mice were used
Project description:The Nrf2 transcription factor is a key player in the cellular stress response, which regulates the expression of important antioxidant enzymes and other cytoprotective proteins. We recently generated a novel transgenic mouse model to determine the function of Nrf2 in the skin. These mice show reduced number of apoptotic keratinocytes after UVB irradiation due to enhanced ROS detoxification. They also show enhanced tumorigenesis in the HPV8 tumor model.
Project description:The nuclear factor erythroid 2-related factor 2 (NRF2) transcription factor activates cytoprotective and metabolic gene expression in response to various electrophilic stressors. In disease, constitutive NRF2 activity promotes cancer progression while decreased NRF2 function contributes to neurodegenerative diseases. In contrast to the regulation of NRF2 protein stability in the cytoplasm, co-complexed proteins that govern NRF2 activity on chromatin are less clear. Using biotin proximity proteomics, we report networks for NRF2 and its family members NRF1, NRF3 and the NRF2 heterodimer MAFG. We found that the Parkinson’s disease zinc finger transcription factor ZNF746 (PARIS) physically associated with NRF2 and MAFG, resulting in suppression of NRF2-driven transcription. ZNF746 expression increased oxidative stress and apoptosis, phenotypes that were reversed by chemical and genetic hyperactivation of NRF2. This study presents a functionally annotated proximity network for NRF2 and suggests that ZNF746 overexpression in Parkinson’s disease directly inhibits NRF2-driven neuroprotection
Project description:The nuclear factor erythroid 2-related factor 2 (NRF2) transcription factor activates cytoprotective and metabolic gene expression in response to various electrophilic stressors. In disease, constitutive NRF2 activity promotes cancer progression while decreased NRF2 function contributes to neurodegenerative diseases. In contrast to the regulation of NRF2 protein stability in the cytoplasm, co-complexed proteins that govern NRF2 activity on chromatin are less clear. Using biotin proximity proteomics, we report networks for NRF2 and its family members NRF1, NRF3 and the NRF2 heterodimer MAFG. We found that the Parkinson’s disease zinc finger transcription factor ZNF746 (PARIS) physically associated with NRF2 and MAFG, resulting in suppression of NRF2-driven transcription. ZNF746 expression increased oxidative stress and apoptosis, phenotypes that were reversed by chemical and genetic hyperactivation of NRF2. This study presents a functionally annotated proximity network for NRF2 and suggests that ZNF746 overexpression in Parkinson’s disease directly inhibits NRF2-driven neuroprotection.
Project description:The activation of the transcription factor NF-E2-related factor 2 (Nrf2) maintains cellular homeostasis in response to oxidative stress by the regulation of multiple cytoprotective genes. Without stressors the activity of Nrf2 is inhibited by its interaction with the kelch-like ECH-associated protein 1 (Keap1). Here, we describe RA839, a small molecule that binds non-covalently to the Nrf2-interacting kelch domain of Keap1 with a Kd of approximately 6 µM, as demonstrated by X-ray co-crystallization and isothermal titration calorimetry. Whole-genome DNA arrays showed that at 10 µM RA839 significantly regulated 105 genes in bone marrow-derived macrophages. Canonical pathway mapping of these genes revealed an activation of pathways linked with Nrf2 signalling. These pathways were also activated after the activation of Nrf2 by the silencing of Keap1 expression. RA839 regulated only two genes in Nrf2 knockout macrophages. Similar to the activation of Nrf2 by either silencing of Keap1 expression or by the reactive compound CDDO-Me, RA839 prevented the induction of both inducible nitric oxide synthase expression and nitric oxide release in response to lipopolysaccharides in macrophages. In mice RA839 acutely induced Nrf2-target gene expression in liver. RA839 is a selective inhibitor of the Keap1/Nrf2 interaction and a useful tool compound to study the biology of Nrf2. Gene expression profile of bone marrow derived murine macrophages (BMDM) from Nrf2+/+ or Nrf2-/- mice treated with RA838, siKeap1-1 or siKeap1-2 were compared to untreated DMSO control or siControl. Four biological replicates were used for each sample group.
Project description:The transcription factor NF-E2-related factor 2 (Nrf2) induces cytoprotective genes, but has also been linked to the regulation of hepatic energy metabolism. In order to assess the pharmacological potential of hepatic Nrf2 activation in metabolic disease, Nrf2 was activated over 8 weeks in mice on Western diet using two different siRNAs against kelch-like ECH-associated protein 1 (Keap1), the inhibitory protein of Nrf2. Whole genome expression analysis followed by pathway analysis demonstrated that the suppression of Keap1 expression induced genes that are involved in anti-oxidative stress defense and biotransformation, pathways proving the activation of Nrf2 by the siRNAs against Keap1. The expression of neither fatty acid- nor carbohydrate-handling proteins was regulated by the suppression of Keap1. Metabolic profiling of the animals did also not show effects on plasma and hepatic lipids, energy expenditure or glucose tolerance by the activation of Nrf2. The data indicate that hepatic Nrf2 is not a major regulator of intermediary metabolism in mice. Gene expression profile of mouse liver samples from 8-week-old male C57BL6/J mice (N=24) treated with liver-selective Keap1-specific siRNA (group 1: siKeap1-1, N=8; group 2: siKeap1-2, N=8) or unspecific scrambled control siRNA (group 3: siControl, N=8)
Project description:The transcription factor NF-E2-related factor 2 (Nrf2) induces cytoprotective genes, but has also been linked to the regulation of hepatic energy metabolism. In order to assess the pharmacological potential of hepatic Nrf2 activation in metabolic disease, Nrf2 was activated over 8 weeks in mice on Western diet using two different siRNAs against kelch-like ECH-associated protein 1 (Keap1), the inhibitory protein of Nrf2. Whole genome expression analysis followed by pathway analysis demonstrated that the suppression of Keap1 expression induced genes that are involved in anti-oxidative stress defense and biotransformation, pathways proving the activation of Nrf2 by the siRNAs against Keap1. The expression of neither fatty acid- nor carbohydrate-handling proteins was regulated by the suppression of Keap1. Metabolic profiling of the animals did also not show effects on plasma and hepatic lipids, energy expenditure or glucose tolerance by the activation of Nrf2. The data indicate that hepatic Nrf2 is not a major regulator of intermediary metabolism in mice.
Project description:Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor that induces a battery of cytoprotective genes in response to oxidative/electrophilic stress. Kelch-like ECH associating protein 1 (Keap1) sequesters Nrf2 in the cytosol. The purpose of this study was to investigate the role of Nrf2 in regulating the mRNA of genes encoding drug metabolizing enzymes and xenobiotic transporters. Microarray analysis was performed in livers of Nrf2-null, wild-type, Keap1-knockdown mice with increased Nrf2 activation, and Keap1-hepatocyte knockout mice with maximum Nrf2 activation. In general, Nrf2 did not have a marked effect on uptake transporters, but the mRNAs of organic anion transporting polypeptide 1a1, sodium taurocholate cotransporting polypeptide, and organic anion transporter 2 were decreased with Nrf2 activation. The effect of Nrf2 on cytochrome P450 (Cyp) genes was minimal, with only Cyp2a5, Cyp2c50, Cyp2c54, and Cyp2g1 increased, and Cyp2u1 decreased with enhanced Nrf2 activation. However, Nrf2 increased mRNA of many other phase-I enzymes, such as aldo-keto reductases, carbonyl reductases, and aldehyde dehydrogenase 1. Many genes involved in phase-II drug metabolism were induced by Nrf2, including glutathione S -transferases, UDP- glucuronosyltransferases, and UDP-glucuronic acid synthesis enzymes. Efflux transporters, such as multidrug resistance-associated proteins, breast cancer resistant protein, as well as ATP-binding cassette g5 and g8 were induced by Nrf2. In conclusion, Nrf2 markedly alters hepatic mRNA of a large number of drug metabolizing enzymes and xenobiotic transporters, and thus Nrf2 plays a central role in xenobiotic metabolism and detoxification. We used microarrays to detail the global programme of gene expression in response to Nrf2 activation and identified distinct classes of up- and down-regulated genes. process. Gene expression in livers of Nrf2-null, WT, Keap1-KD, and Keap1-HKO mice was determined using Affymetrix Mouse 430.20 arrays by the KUMC Microarray Core Facility. Biological cRNA replicates (n=3) of each genotype were hybridized to an individual array.
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.