Pexophagy-driven redox imbalance promotes virus-induced ferroptosis
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE295522 | GEO | 2025/04/29
REPOSITORIES: GEO
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Project description:Peroxisomes are membrane-bound organelles that help cells specialize their metabolism. In humans, peroxisomes are required for normal development, yet the genes regulating peroxisome function remain unclear. Thus, we performed a genome-wide CRISPRi screen to identify novel factors involved in peroxisomal homeostasis. We found that transcriptional inhibition of RNF146, an E3 ligase activated by poly(ADP-ribose), dramatically reduced the import of proteins into peroxisomes. The observed RNF146-mediated loss of peroxisome import depended on the stabilization and activity of the poly(ADP-ribose) polymerase tankyrase, which binds the peroxisomal membrane protein PEX14. We propose a model in which RNF146 and tankyrase regulate peroxisome import efficiency by tuning PARsylation of proteins at the peroxisome membrane. Interestingly, we found that perturbations to peroxisomes altered tankyrase’s selection of substrates, including the beta-catenin destruction complex component AXIN1. The loss of peroxisomes caused tankyrase and RNF146-dependent degradation of AXIN1 and a concomitant increase of beta-catenin transcription. Together, these observations not only suggest previously undescribed roles for RNF146 in peroxisomal regulation, but also a novel role in bridging peroxisome function with Wnt/beta-catenin signaling during development.
2024-06-01 | GSE266855 | GEO
Project description:Peroxisomes are membrane-bound organelles that help cells specialize their metabolism. In humans, peroxisomes are required for normal development, yet the genes regulating peroxisome function remain unclear. Thus, we performed a genome-wide CRISPRi screen to identify novel factors involved in peroxisomal homeostasis. We found that transcriptional inhibition of RNF146, an E3 ligase activated by poly(ADP-ribose), dramatically reduced the import of proteins into peroxisomes. The observed RNF146-mediated loss of peroxisome import depended on the stabilization and activity of the poly(ADP-ribose) polymerase tankyrase, which binds the peroxisomal membrane protein PEX14. We propose a model in which RNF146 and tankyrase regulate peroxisome import efficiency by tuning PARsylation of proteins at the peroxisome membrane. Interestingly, we found that perturbations to peroxisomes altered tankyrase’s selection of substrates, including the beta-catenin destruction complex component AXIN1. The loss of peroxisomes caused tankyrase and RNF146-dependent degradation of AXIN1 and a concomitant increase of beta-catenin transcription. Together, these observations not only suggest previously undescribed roles for RNF146 in peroxisomal regulation, but also a novel role in bridging peroxisome function with Wnt/beta-catenin signaling during development.
2024-06-01 | GSE266892 | GEO
Project description:Peroxisomes are organelles that are crucial for cellular metabolism. However, these organelles play also important roles in non-metabolic processes, such as signalling. To uncover the consequences of peroxisome deficiency, we compared two extremes, namely Saccharomyces cerevisiae wild-type and pex3 cells, which lack functional peroxisomes, employing transcriptomics and quantitative proteomics technology. Cells were grown on acetate, a carbon source that involves peroxisomal enzymes of the glyoxylate cycle and does not repress peroxisomal proteins. Transcripts of peroxisomal β-oxidation genes and the corresponding proteins were enhanced in pex3 cells. Peroxisome-deficiency also caused reduced levels of membrane bound peroxins, while the soluble receptors Pex5 and Pex7 were enhanced at the protein level. In addition, we observed alterations in non-peroxisomal transcripts and proteins, especially mitochondrial proteins involved in respiration or import processes. Our results not only reveal the impact of the absence of peroxisomes in yeast, but also represent a rich resource of candidate genes/proteins that are relevant in peroxisome biology.
2024-05-01 | GSE261289 | GEO
Project description:Despite the introduction of effective treatments for hepatitis C in clinics, issues remain regarding the liver diseases induced by chronic hepatitis C virus (HCV) infection. HCV is known to disturb the metabolism of infected cells, especially lipid metabolism and redox balance, but the mechanisms leading to HCV-induced pathogenesis are still poorly understood. In an APEX2-based proximity biotinylation screen, we identified ACBD5, a peroxisome membrane protein, as located in the vicinity of HCV replication complexes. Confocal microscopy confirmed the relocation of peroxisomes near HCV replication complexes and indicated that their morphology and number are altered in approximately 30% of infected Huh-7 cells. Peroxisomes are small versatile organelles involved among other functions in lipid metabolism and ROS regulation. To determine their importance in the HCV life cycle, we generated Huh-7 cells devoid of peroxisomes by inactivating the PEX5 and PEX3 genes using CRISPR/Cas9 and found that the absence of peroxisomes had no impact on replication kinetics or infectious titers of HCV strains JFH1 and DBN3a. The impact of HCV on peroxisomal functions was assessed using sub-genomic replicons. An increase of ROS was measured in peroxisomes of replicon-containing cells, and this increase was more pronounced than in mitochondria or the cytosol, suggesting that the redox balance of peroxisomes is specifically impaired in cells replicating HCV. Our study provides evidence that peroxisome function and morphology are altered in HCV-infected cells.
2023-10-24 | PXD044994 | Pride
Project description:This is a pioneer genome-wide study of localization of mRNAs to peroxisomes. The findings suggest that translation of a subset of peroxiomal proteins and other cellular metabolic enzymes may be spatially regulated by directing their encoding mRNAs to the surface of peroxisomes. The study provides foundation for more detailed dissection of mechanisms of RNA targeting to subcellular compartments. In this study we performed the genome-wide transcriptome analysis of peroxisome preparations from the mouse liver using microarrays. We demonstrate that RNA is absent inside peroxisomes, however it is associated at their exterior via the noncovalent contacts with the membrane proteins. We detect enrichment of specific sets of transcripts in two preparations of peroxisomes, purified with different degrees of stringency. Importantly, among these were mRNAs encoding bona fide peroxisomal proteins, such as peroxins and peroxisomal matrix enzymes involved in beta-oxidation of fatty acids and bile acid biosynthesis. Two subcellular fractions were obtained from the mouse liver by centrifugation in iodixanol density gradient: 1) Peroxisomal (PX), 2) Mitochondrial/Lysosomal (ML). The membrane-enclosed peroxisomal fraction (PX-IP) was obtained by immuno-precispitation of the PX fraction with the PMP70-specific antibodies. RNA was extracted from each fraction. Additionally, the total cellular RNA was obtained from the whole cell extracts (T). Thus, four RNA sample types were obtained for gene expression analysis: T, ML, PX, PI. Three technical replicates of each sample ware analyzed with Illumina microarrays.
2016-07-29 | E-GEOD-84972 | biostudies-arrayexpress
Project description:This is a pioneer genome-wide study of localization of mRNAs to peroxisomes. The findings suggest that translation of a subset of peroxiomal proteins and other cellular metabolic enzymes may be spatially regulated by directing their encoding mRNAs to the surface of peroxisomes. The study provides foundation for more detailed dissection of mechanisms of RNA targeting to subcellular compartments. In this study we performed the genome-wide transcriptome analysis of peroxisome preparations from the mouse liver using microarrays. We demonstrate that RNA is absent inside peroxisomes, however it is associated at their exterior via the noncovalent contacts with the membrane proteins. We detect enrichment of specific sets of transcripts in two preparations of peroxisomes, purified with different degrees of stringency. Importantly, among these were mRNAs encoding bona fide peroxisomal proteins, such as peroxins and peroxisomal matrix enzymes involved in beta-oxidation of fatty acids and bile acid biosynthesis.
2016-07-29 | GSE84972 | GEO
Project description:Ever since the first characterization of peroxisomes, a central theme has been their involvement in cellular hydrogen peroxide (H2O2) metabolism. While the reputation of H2O2 drastically changed from an exclusively toxic molecule to a signaling messenger, the regulatory role of peroxisomes in these signaling events is still largely underappreciated. This is mainly because the number of known protein targets of peroxisome-derived H2O2 is rather limited and testing of specific targets is predominantly based on knowledge previously gathered in related fields of research. To gain a broader and more systematic insight into the role of peroxisomes in redox signaling, new approaches are urgently needed. In this study, we have combined a previously developed Flp-In T-REx 293 cell system in which peroxisomal H2O2 production can be modulated with a yeast AP-1-like-based sulfenome mining strategy to inventory protein thiol targets of peroxisome-derived H2O2 in different subcellular compartments. Using this approach, we were able to identify specific and common targets of peroxisome-derived and exogenous H2O2 in peroxisomes, the cytosol, and mitochondria. We also observed that the sulfenylation kinetics profiles of key targets (e.g., PRDX1, ANXA2, and TUBA1C) belonging to different protein families (e.g., antioxidants, annexins, and tubulins) can vary considerably. In addition, we obtained compelling but indirect evidence that peroxisome-derived H2O2 may oxidize at least some of its targets (e.g., transcription factors) through a redox relay mechanism. In conclusion, given that sulfenic acids function as key intermediates in H2O2 signaling, the findings presented in this study provide initial but critical insight into how peroxisomes may be integrated into the cellular H2O2 signaling network.
2022-05-10 | PXD030782 | Pride
Project description:Several proteomics studies have been performed in the past in order to define the mammalian peroxisomal proteome. During the last decade, it has as well become evident, that a significant number of proteins is shared between several subcellular compartments and that specialized proteins subsets are constituents of membrane contact zones, which bridge two adjacent organelle to allow metabolite exchange. In this respect, a number of proteins, which have been considered as mere contaminants in previous studies, might be indeed proteins, which are to a minor extent indeed truly associated with peroxisomes. Ongoing technical improvements in mass spectrometry (MS) allow to identify and to quantify the enrichment of such less abundant proteins in individual fractions. Accordingly, this study reassessed the proteome of mouse liver peroxisomes by parallel isolation of peroxisomes from a mitochondria- and a microsome-enriched pre-fraction combining density gradient centrifugation with a SWATH-MS quantitative proteomics approach to unveil novel peroxisomal or peroxisome-associated proteins. In total, 1071 proteins from the MS-samples were identified in amounts, which allowed their quantification in order to assess their enrichment in either high density peroxisomal or low-density gradient fractions, containing the bulk of organelle material. Combining the data from isolations from the mitochondria- and microsome-enriched prefractions allowed to identify specific protein clusters characteristic for mitochondria, the ER and peroxisomes. Among the proteins, which were significantly enriched in the peroxisomal cluster, were several proteins, which were not previously associated with the organelles implying that they are novel peroxisomal candidates. In order to validate the organelle proteomics strategy, five of the candidates were selected for further colocalization studies. The peroxismal import of two candidates, HTATIP2 and PAFAH2, which contain potential peroxisome targeting sequences 1, could be confirmed by overexpression in HepG2 cells. Two other candidates, SAR1B and PDCD6, which are known from ER exit sites, did not directly colocalize with peroxisomes but were found to reside at ER sites which often surrounded peroxisomes. Hence, both proteins might concentrate at peroxisome-ER membrane contact sites, which might be co-purified with peroxisomes. Intriguingly, the last candidate, OCIA domain-containing protein 1, was previously described to decrease mitochondrial branching and network formation. In this work, we not only validate its secondary peroxisomal localization but also observed a reduction in peroxisome numbers in response OCIAD1 expression. Hence, OCIAD1 appears to be a novel protein, which has an impact on both mitochondrial and peroxisomal maintenance.
2024-06-22 | PXD047931 | Pride
Project description:Detection of viral RNA in the cytosol of infected cells depends on RIG-I-lilke recptors that use MAVS as an adapter protein to activate antiviral gene expression. MAVS is tail-anchored on mitochondria, mitochondria-associated membranes and peroxisomes. As peroxisomal membrane proteins can be mistargeted to mitochondria in the absence of peroxisomes, we hypothesized that MAVS-dependent antiviral gene expression is activated more efficiently in this instance. Pex19 deficient skin firoblasts derived from a Zellweger syndrome patient lack peroxisomes. We introduced wild type Pex19 into these cells to restore peroxisome formation and assessed alterations in the gene expression profile of these cells after reovirus infection.
2014-04-15 | GSE56783 | GEO
Project description:Detection of viral RNA in the cytosol of infected cells depends on RIG-I-lilke recptors that use MAVS as an adapter protein to activate antiviral gene expression. MAVS is tail-anchored on mitochondria, mitochondria-associated membranes and peroxisomes. As peroxisomal membrane proteins can be mistargeted to mitochondria in the absence of peroxisomes, we hypothesized that MAVS-dependent antiviral gene expression is activated more efficiently in this instance. Pex19 deficient skin firoblasts derived from a Zellweger syndrome patient lack peroxisomes. We introduced wild type Pex19 into these cells to restore peroxisome formation and assessed alterations in the gene expression profile of these cells after reovirus infection. 6 samples: 9 and 16 hrs after reovirus infection at an MOI of 100 total RNA was extracted from Pex19 reconstituted and deficient cell lines. Gene expression data was compared to uninfected cells.
2014-04-15 | E-GEOD-56783 | biostudies-arrayexpress