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Ibrahim L, Mesgarzadeh J, Xu I, Powers ET, Wiseman RL, Bollong MJ. Defining the Functional Targets of Cap'n'collar Transcription Factors NRF1, NRF2, and NRF3. Antioxidants (Basel) 2020; 9:E1025. [PMID: 33096892 PMCID: PMC7588902 DOI: 10.3390/antiox9101025] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Revised: 10/14/2020] [Accepted: 10/19/2020] [Indexed: 12/18/2022] Open
Abstract
The NRF transcription factors NRF1, NRF2, and NRF3, are a subset of Cap'n'collar transcriptional regulators which modulate the expression of genes harboring antioxidant-response element (ARE) sequences within their genomic loci. Despite the emerging physiological importance of NRF family members, the repertoire of their genetic targets remains incompletely defined. Here we use RNA-sequencing-based transcriptional profiling and quantitative proteomics to delineate the overlapping and differential genetic programs effected by the three NRF transcription factors. We then create consensus target gene sets regulated by NRF1, NRF2, and NRF3 and define the integrity of these gene sets for probing NRF activity in mammalian cell culture and human tissues. Together, our data provide a quantitative assessment of how NRF family members sculpt proteomes and transcriptomes, providing a framework to understand the critical physiological importance of NRF transcription factors and to establish pharmacologic approaches for therapeutically activating these transcriptional programs in disease.
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Affiliation(s)
- Lara Ibrahim
- Department of Molecular Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA; (L.I.); (J.M.); (I.X.); (R.L.W.)
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA;
| | - Jaleh Mesgarzadeh
- Department of Molecular Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA; (L.I.); (J.M.); (I.X.); (R.L.W.)
| | - Ian Xu
- Department of Molecular Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA; (L.I.); (J.M.); (I.X.); (R.L.W.)
| | - Evan T. Powers
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA;
| | - R. Luke Wiseman
- Department of Molecular Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA; (L.I.); (J.M.); (I.X.); (R.L.W.)
| | - Michael J. Bollong
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA;
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An integrated multi-omics approach identifies epigenetic alterations associated with Alzheimer's disease. Nat Genet 2020; 52:1024-1035. [PMID: 32989324 PMCID: PMC8098004 DOI: 10.1038/s41588-020-0696-0] [Citation(s) in RCA: 186] [Impact Index Per Article: 46.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Accepted: 08/20/2020] [Indexed: 12/19/2022]
Abstract
Protein aggregation is the hallmark of neurodegeneration but the molecular mechanisms underlying late-onset Alzheimer’s disease (AD) remain unclear. Here we integrated transcriptomic, proteomic and epigenomic analyses of post-mortem human brains to identify molecular pathways involved in AD. RNA-seq analysis revealed upregulation of transcription- and chromatin-related genes, including the histone acetyltransferases for H3K27ac and H3K9ac. An unbiased proteomic screening singled out H3K27ac and H3K9ac as main enrichments specific to AD. In turn, epigenomic profiling revealed gains of H3K27ac and H3K9ac linked to transcription, chromatin, and disease pathways in AD. Increasing genome-wide H3K27ac and H3K9ac in a fly model of AD exacerbated amyloid-β42-driven neurodegeneration. Together, these findings suggest that AD involves a reconfiguration of the epigenome, where H3K27ac and H3K9ac impact disease pathways by dysregulating transcription- and chromatin-gene feedback loops. The identification of this process highlights potential epigenetic strategies for early-stage disease treatment.
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Trash Talk: Mammalian Proteasome Regulation at the Transcriptional Level. Trends Genet 2020; 37:160-173. [PMID: 32988635 DOI: 10.1016/j.tig.2020.09.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 08/21/2020] [Accepted: 09/01/2020] [Indexed: 12/27/2022]
Abstract
The key to a healthy mammalian cell lies in properly functioning proteolytic machineries called proteasomes. The proteasomes are multisubunit complexes that catalyze the degradation of unwanted proteins and also control half-lives of key cellular regulatory factors. Aberrant proteasome activity is often associated with human diseases such as cancer and neurodegeneration, and so an in-depth understanding of how it is regulated has implications for potential disease interventions. Transcriptional regulation of the proteasome can dictate its abundance and also influence its function, assembly, and location. This ensures proper proteasomal activity in response to developmental cues and to physiological conditions such as starvation and oxidative stress. In this review, we highlight and discuss the roles of the transcription factors that are involved in the regulation of the mammalian proteasome.
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Mitochondrial Respiratory Defect Enhances Hepatoma Cell Invasiveness via STAT3/NFE2L1/STX12 Axis. Cancers (Basel) 2020; 12:cancers12092632. [PMID: 32942643 PMCID: PMC7565734 DOI: 10.3390/cancers12092632] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 09/10/2020] [Accepted: 09/14/2020] [Indexed: 12/30/2022] Open
Abstract
Simple Summary Mitochondria are essential organelles responsible for aerobic ATP production in eukaryotes. However, many solid tumor cells harbor an impaired mitochondrial ATP production system: oxidative phosphorylation (OXPHOS). The aim of this study was to elucidate the involvement of the mitochondrial OXPHOS defect in cancer cell activity, especially focusing on hepatoma cell invasiveness. We demonstrated that NADH:Ubiquinone Oxidoreductase Subunit A9 (NDUFA9) depletion was an upstream driver of the OXPHOS defect and nuclear factor-erythroid 2 like 1 (NFE2L1) upregulation in HCC tumors. NFE2L1 is the key transcription factor to enhance hepatoma cell invasiveness via STX12 expression. Our study presents a novel mitochondrial dysfunction-mediated retrograde signaling pathway and the resulting transcriptomic reprogramming in liver cancer progression, providing the NDUFA9/NFE2L1/STX12 axis as a key prognostic marker of aggressive liver cancer with mitochondrial defects. Abstract Mitochondrial respiratory defects have been implicated in cancer progression and metastasis, but how they control tumor cell aggressiveness remains unclear. Here, we demonstrate that a mitochondrial respiratory defect induces nuclear factor-erythroid 2 like 1 (NFE2L1) expression at the transcriptional level via reactive oxygen species (ROS)-mediated STAT3 activation. We identified syntaxin 12 (STX12) as an effective downstream target of NFE2L1 by performing cDNA microarray analysis after the overexpression and depletion of NFE2L1 in hepatoma cells. Bioinformatics analysis of The Cancer Genome Atlas Liver Hepatocellular carcinoma (TCGA-LIHC) open database (n = 371) also revealed a significant positive association (r = 0.3, p = 2.49 × 10−9) between NFE2L1 and STX12 expression. We further demonstrated that STX12 is upregulated through the ROS/STAT3/NFE2L1 axis and is a key downstream effector of NFE2L1 in modulating hepatoma cell invasiveness. In addition, gene enrichment analysis of TCGA-LIHC also showed that epithelial–mesenchymal transition (EMT)-related core genes are significantly upregulated in tumors co-expressing NFE2L1 and STX12. The positive association between NFE2L1 and STX12 expression was validated by immunohistochemistry of the hepatocellular carcinoma tissue array. Finally, higher EMT gene enrichment and worse overall survival (p = 0.043) were observed in the NFE2L1 and STX12 co-expression group with mitochondrial defect, as indicated by low NDUFA9 expression. Collectively, our results indicate that NFE2L1 is a key mitochondrial retrograde signaling-mediated primary gene product enhancing hepatoma cell invasiveness via STX12 expression and promoting liver cancer progression.
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Wang S, Zhou D, Xu Z, Song J, Qian X, Lv X, Luan J. Anti-tumor Drug Targets Analysis: Current Insight and Future Prospect. Curr Drug Targets 2020; 20:1180-1202. [PMID: 30947670 DOI: 10.2174/1389450120666190402145325] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 03/21/2019] [Accepted: 03/22/2019] [Indexed: 12/13/2022]
Abstract
The incidence and mortality of malignant tumors are on the rise, which has become the second leading cause of death in the world. At present, anti-tumor drugs are one of the most common methods for treating cancer. In recent years, with the in-depth study of tumor biology and related disciplines, it has been gradually discovered that the essence of cell carcinogenesis is the infinite proliferation of cells caused by the disorder of cell signal transduction pathways, followed by a major shift in the concept of anti-tumor drugs research and development. The focus of research and development is shifting from traditional cytotoxic drugs to a new generation of anti-tumor drugs targeted at abnormal signaling system targets in tumor cells. In this review, we summarize the targets of anti-tumor drugs and analyse the molecular mechanisms of their effects, which lay a foundation for subsequent treatment, research and development.
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Affiliation(s)
- Sheng Wang
- Department of Pharmacy, Yijishan Affiliated Hospital of Wannan Medical College, Wuhu, Anhui Province, China
| | - Dexi Zhou
- Department of Pharmacy, Yijishan Affiliated Hospital of Wannan Medical College, Wuhu, Anhui Province, China
| | - Zhenyu Xu
- Department of Pharmacy, Yijishan Affiliated Hospital of Wannan Medical College, Wuhu, Anhui Province, China
| | - Jing Song
- Department of Pharmacy, Yijishan Affiliated Hospital of Wannan Medical College, Wuhu, Anhui Province, China
| | - Xueyi Qian
- Department of Pharmacy, Yijishan Affiliated Hospital of Wannan Medical College, Wuhu, Anhui Province, China
| | - Xiongwen Lv
- The Key Laboratory of Anti-inflammatory and Immune Medicines, Ministry of Education, School of Pharmacy, Institute for Liver Disease of Anhui Medical University, Hefei, Anhui Province, China
| | - Jiajie Luan
- Department of Pharmacy, Yijishan Affiliated Hospital of Wannan Medical College, Wuhu, Anhui Province, China
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NFE2L1 and NFE2L3 Complementarily Maintain Basal Proteasome Activity in Cancer Cells through CPEB3-Mediated Translational Repression. Mol Cell Biol 2020; 40:MCB.00010-20. [PMID: 32366381 DOI: 10.1128/mcb.00010-20] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 04/27/2020] [Indexed: 11/20/2022] Open
Abstract
Proteasomes are protease complexes essential for cellular homeostasis, and their activity is crucial for cancer cell growth. However, the mechanism of how proteasome activity is maintained in cancer cells has remained unclear. The CNC family transcription factor NFE2L1 induces the expression of almost all proteasome-related genes under proteasome inhibition. Both NFE2L1 and its phylogenetically closest homolog, NFE2L3, are highly expressed in several types of cancer, such as colorectal cancer. Here, we demonstrate that NFE2L1 and NFE2L3 complementarily maintain basal proteasome activity in cancer cells. Double knockdown of NFE2L1 and NFE2L3 impaired basal proteasome activity in cancer cells and cancer cell resistance to a proteasome inhibitor anticancer drug, bortezomib, by significantly reducing the basal expression of seven proteasome-related genes: PSMB3, PSMB7, PSMC2, PSMD3, PSMG2, PSMG3, and POMP Interestingly, the molecular basis behind these cellular consequences was that NFE2L3 repressed NFE2L1 translation by the induction of the gene encoding the translational regulator CPEB3, which binds to the NFE2L1 3' untranslated region and decreases polysome formation on NFE2L1 mRNA. Consistent results were obtained from clinical analysis, wherein patients with cancer having tumors expressing higher levels of CPEB3/NFE2L3 exhibit poor prognosis. These results provide the novel regulatory mechanism of basal proteasome activity in cancer cells through an NFE2L3-CPEB3-NFE2L1 translational repression axis.
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57
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Hamazaki J, Murata S. ER-Resident Transcription Factor Nrf1 Regulates Proteasome Expression and Beyond. Int J Mol Sci 2020; 21:ijms21103683. [PMID: 32456207 PMCID: PMC7279161 DOI: 10.3390/ijms21103683] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 05/18/2020] [Accepted: 05/20/2020] [Indexed: 02/06/2023] Open
Abstract
Protein folding is a substantively error prone process, especially when it occurs in the endoplasmic reticulum (ER). The highly exquisite machinery in the ER controls secretory protein folding, recognizes aberrant folding states, and retrotranslocates permanently misfolded proteins from the ER back to the cytosol; these misfolded proteins are then degraded by the ubiquitin–proteasome system termed as the ER-associated degradation (ERAD). The 26S proteasome is a multisubunit protease complex that recognizes and degrades ubiquitinated proteins in an ATP-dependent manner. The complex structure of the 26S proteasome requires exquisite regulation at the transcription, translation, and molecular assembly levels. Nuclear factor erythroid-derived 2-related factor 1 (Nrf1; NFE2L1), an ER-resident transcription factor, has recently been shown to be responsible for the coordinated expression of all the proteasome subunit genes upon proteasome impairment in mammalian cells. In this review, we summarize the current knowledge regarding the transcriptional regulation of the proteasome, as well as recent findings concerning the regulation of Nrf1 transcription activity in ER homeostasis and metabolic processes.
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58
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Rey F, Balsari A, Giallongo T, Ottolenghi S, Di Giulio AM, Samaja M, Carelli S. Erythropoietin as a Neuroprotective Molecule: An Overview of Its Therapeutic Potential in Neurodegenerative Diseases. ASN Neuro 2020; 11:1759091419871420. [PMID: 31450955 PMCID: PMC6712762 DOI: 10.1177/1759091419871420] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Erythropoietin (EPO) is a cytokine mainly induced in hypoxia conditions. Its major production site is the kidney. EPO primarily acts on the erythroid progenitor cells in the bone marrow. More and more studies are highlighting its secondary functions, with a crucial focus on its role in the central nervous system. Here, EPO may interact with up to four distinct isoforms of its receptor (erythropoietin receptor [EPOR]), activating different signaling cascades with roles in neuroprotection and neurogenesis. Indeed, the EPO/EPOR axis has been widely studied in the neurodegenerative diseases field. Its potential therapeutic effects have been evaluated in multiple disorders, such as Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis, spinal cord injury, as well as brain ischemia, hypoxia, and hyperoxia. EPO is showing great promise by counteracting secondary neuroinflammatory processes, reactive oxygen species imbalance, and cell death in these diseases. Multiple studies have been performed both in vitro and in vivo, characterizing the mechanisms through which EPO exerts its neurotrophic action. In some cases, clinical trials involving EPO have been performed, highlighting its therapeutic potential. Together, all these works indicate the potential beneficial effects of EPO.
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Affiliation(s)
- Federica Rey
- 1 Laboratory of Pharmacology, Department of Health Sciences, University of Milan, Italy
| | - Alice Balsari
- 1 Laboratory of Pharmacology, Department of Health Sciences, University of Milan, Italy
| | - Toniella Giallongo
- 1 Laboratory of Pharmacology, Department of Health Sciences, University of Milan, Italy
| | - Sara Ottolenghi
- 2 Laboratory of Biochemistry, Department of Health Sciences, University of Milan, Italy
| | - Anna M Di Giulio
- 1 Laboratory of Pharmacology, Department of Health Sciences, University of Milan, Italy.,3 Pediatric Clinical Research Center Fondazione "Romeo ed Enrica Invernizzi", University of Milan, Italy
| | - Michele Samaja
- 2 Laboratory of Biochemistry, Department of Health Sciences, University of Milan, Italy
| | - Stephana Carelli
- 1 Laboratory of Pharmacology, Department of Health Sciences, University of Milan, Italy.,3 Pediatric Clinical Research Center Fondazione "Romeo ed Enrica Invernizzi", University of Milan, Italy
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Nrf1 Is Endowed with a Dominant Tumor-Repressing Effect onto the Wnt/ β-Catenin-Dependent and Wnt/ β-Catenin-Independent Signaling Networks in the Human Liver Cancer. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2020; 2020:5138539. [PMID: 32273945 PMCID: PMC7125503 DOI: 10.1155/2020/5138539] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 02/20/2020] [Indexed: 12/17/2022]
Abstract
Our previous work revealed that Nrf1α exerts a tumor-repressing effect because its genomic loss (to yield Nrf1α-/- ) results in oncogenic activation of Nrf2 and target genes. Interestingly, β-catenin is concurrently activated by loss of Nrf1α in a way similar to β-catenin-driven liver tumor. However, a presumable relationship between Nrf1 and β-catenin is not yet established. Here, we demonstrate that Nrf1 enhanced ubiquitination of β-catenin for targeting proteasomal degradation. Conversely, knockdown of Nrf1 by its short hairpin RNA (shNrf1) caused accumulation of β-catenin so as to translocate the nucleus, allowing activation of a subset of Wnt/β-catenin signaling responsive genes, which leads to the epithelial-mesenchymal transition (EMT) and related cellular processes. Such silencing of Nrf1 resulted in malgrowth of human hepatocellular carcinoma, along with malignant invasion and metastasis to the lung and liver in xenograft model mice. Further transcriptomic sequencing unraveled significant differences in the expression of both Wnt/β-catenin-dependent and Wnt/β-catenin-independent responsive genes implicated in the cell process, shape, and behavior of the shNrf1-expressing tumor. Notably, we identified that β-catenin is not a target gene of Nrf1, but this CNC-bZIP factor contributes to differential or opposing expression of other critical genes, such as CDH1, Wnt5A, Wnt11A, FZD10, LEF1, TCF4, SMAD4, MMP9, PTEN, PI3K, JUN, and p53, each of which depends on the positioning of distinct cis-regulatory sequences (e.g., ARE and/or AP-1 binding sites) in the gene promoter contexts. In addition, altered expression profiles of some Wnt/β-catenin signaling proteins were context dependent, as accompanied by decreased abundances of Nrf1 in the clinic human hepatomas with distinct differentiation. Together, these results corroborate the rationale that Nrf1 acts as a bona fide dominant tumor repressor, by its intrinsic inhibition of Wnt/β-catenin signaling and relevant independent networks in cancer development and malignant progression.
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60
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Overexpression of NRF1-742 or NRF1-772 Reduces Arsenic-Induced Cytotoxicity and Apoptosis in Human HaCaT Keratinocytes. Int J Mol Sci 2020; 21:ijms21062014. [PMID: 32188015 PMCID: PMC7139366 DOI: 10.3390/ijms21062014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 02/26/2020] [Accepted: 03/12/2020] [Indexed: 02/06/2023] Open
Abstract
Increasing evidence indicates that human exposure to inorganic arsenic causes cutaneous diseases and skin cancers. Nuclear factor erythroid 2-like 1 (NRF1) belongs to the cap “n” collar (CNC) basic-region leucine zipper (bZIP) transcription factor family and regulates antioxidant response element (ARE) genes. The human NRF1 gene is transcribed into multiple isoforms, which contain 584, 616, 742, 761, or 772 amino acids. We previously demonstrated that the long isoforms of NRF1 (i.e., NRF1-742, NRF1-761 and NRF1-772) are involved in the protection of human keratinocytes from acute arsenic cytotoxicity by enhancing the cellular antioxidant response. The aim of the current study was to investigate the roles of NRF1-742 and NRF1-772 in the arsenic-induced antioxidant response and cytotoxicity. We found that overexpression of NRF1-742 or NRF1-772 in human HaCaT keratinocytes decreased susceptibility to arsenic-induced apoptosis and cytotoxicity. In addition, we characterized the different protein bands observed for NRF1-742 and NRF1-772 by western blotting. The posttranslational modifications and nuclear translocation of these isoforms differed and were partially affected by arsenic exposure. Antioxidant protein levels were increased in the NRF1-742 and NRF1-772-overexpressing cell lines. The upregulation of antioxidant protein levels was partly due to the translation of nuclear factor erythroid 2-like 2 (NRF2) and its increased nuclear transport. Overall, overexpression of NRF1-742 and NRF1-772 protected HaCaT cells from arsenic-induced cytotoxicity, mainly through translational modifications and the promotion of antioxidant gene expression.
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61
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Lehrbach NJ, Breen PC, Ruvkun G. Protein Sequence Editing of SKN-1A/Nrf1 by Peptide:N-Glycanase Controls Proteasome Gene Expression. Cell 2020; 177:737-750.e15. [PMID: 31002798 DOI: 10.1016/j.cell.2019.03.035] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 12/14/2018] [Accepted: 03/15/2019] [Indexed: 12/20/2022]
Abstract
The proteasome mediates selective protein degradation and is dynamically regulated in response to proteotoxic challenges. SKN-1A/Nrf1, an endoplasmic reticulum (ER)-associated transcription factor that undergoes N-linked glycosylation, serves as a sensor of proteasome dysfunction and triggers compensatory upregulation of proteasome subunit genes. Here, we show that the PNG-1/NGLY1 peptide:N-glycanase edits the sequence of SKN-1A protein by converting particular N-glycosylated asparagine residues to aspartic acid. Genetically introducing aspartates at these N-glycosylation sites bypasses the requirement for PNG-1/NGLY1, showing that protein sequence editing rather than deglycosylation is key to SKN-1A function. This pathway is required to maintain sufficient proteasome expression and activity, and SKN-1A hyperactivation confers resistance to the proteotoxicity of human amyloid beta peptide. Deglycosylation-dependent protein sequence editing explains how ER-associated and cytosolic isoforms of SKN-1 perform distinct cytoprotective functions corresponding to those of mammalian Nrf1 and Nrf2. Thus, we uncover an unexpected mechanism by which N-linked glycosylation regulates protein function and proteostasis.
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Affiliation(s)
- Nicolas J Lehrbach
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Peter C Breen
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Gary Ruvkun
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Genetics, Harvard Medical School, Boston, MA 02115, USA.
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Xue P, Hou Y, Zuo Z, Wang Z, Ren S, Dong J, Fu J, Wang H, Andersen ME, Zhang Q, Xu Y, Pi J. Long isoforms of NRF1 negatively regulate adipogenesis via suppression of PPARγ expression. Redox Biol 2019; 30:101414. [PMID: 31931283 PMCID: PMC6957832 DOI: 10.1016/j.redox.2019.101414] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 12/02/2019] [Accepted: 12/23/2019] [Indexed: 01/12/2023] Open
Abstract
Nuclear factor erythroid 2-related factor 1 (NRF1), a ubiquitously expressed CNC-bZIP transcription factor, plays a critical role in white adipocyte (WAC) biology, whereas the underlying mechanisms remain unknown. The mouse Nrf1 gene is transcribed in a number of alternatively spliced forms, resulting in two long protein isoforms (L-NRF1) containing 741 and 742 amino acids (aa) and multiple short isoforms (S-NRF1). Our previous study found that adipocyte-specific knockout of Nrf1 [Nrf1(f)-KO] in mice disturbs the expression of lipolytic genes in adipocytes, leading to adipocyte hypertrophy followed by inflammation, pyroptosis and insulin resistance. In the present study, we found that the stromal vascular fraction (SVF) cells isolated from white adipose tissues (WAT) of Nrf1(f)-KO mice display augmented adipogenesis showing elevated mRNA and protein expression of adipogenic markers and lipid accumulation. In 3T3-L1 cells, stable knockdown (KD) of all or long isoforms of Nrf1 (termed as A-Nrf1-KD and L-Nrf1-KD, respectively) using lentiviral shRNAs resulted in enhanced and accelerated adipogenic differentiation. Conversely, overexpression of L-NRF1-741, but not any of the S-NRF1, substantially attenuated adipogenesis in 3T3-L1 cells. These findings indicate that L-NRF1 might serve as a critical negative regulator of adipogenesis. Mechanistic investigation revealed that L-NRF1 may negatively regulates the transcription of peroxisome proliferator-activated receptor γ (PPARγ), in particular the master regulator of adipogenesis PPARγ2. Taken all together, the findings in the present study provide further evidence for a novel role of NRF1 beyond its participation in cellular antioxidant response and suggest that L-NRF1 is a negative regulator of PPARγ2 expression and thereby can suppress adipogenesis. SVF cells isolated from WAT of Nrf1(f)-KO mice displayed augmented adipogenesis. Stable silencing of L-Nrf1 in 3T3-L1 cells resulted in enhanced and accelerated adipogenesis. Overexpression of L-NRF1-741, but not S-NRF1s, attenuated adipogenesis in 3T3-L1 cells. L-NRF1 suppressed adipogenesis via downregulating PPARγ2 expression.
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Affiliation(s)
- Peng Xue
- School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang, Liaoning, 110122, PR China; ScitoVation LLC, Research Triangle Park, NC, USA
| | - Yongyong Hou
- School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang, Liaoning, 110122, PR China
| | - Zhuo Zuo
- School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang, Liaoning, 110122, PR China
| | - Zhendi Wang
- School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang, Liaoning, 110122, PR China
| | - Suping Ren
- School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang, Liaoning, 110122, PR China
| | - Jian Dong
- ScitoVation LLC, Research Triangle Park, NC, USA
| | - Jingqi Fu
- School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang, Liaoning, 110122, PR China
| | - Huihui Wang
- School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang, Liaoning, 110122, PR China
| | | | - Qiang Zhang
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA, USA
| | - Yuanyuan Xu
- School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang, Liaoning, 110122, PR China.
| | - Jingbo Pi
- School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang, Liaoning, 110122, PR China.
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TRIM59 expression is regulated by Sp1 and Nrf1 in LPS-activated macrophages through JNK signaling pathway. Cell Signal 2019; 67:109522. [PMID: 31883458 DOI: 10.1016/j.cellsig.2019.109522] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 12/23/2019] [Accepted: 12/23/2019] [Indexed: 12/19/2022]
Abstract
Activated macrophages play an important role in many inflammatory diseases including septic shock and atherosclerosis. TRIM59 has been showed to participate in many pathological processes, such as inflammation, cytotoxicity and tumorigenesis. However, the molecular mechanisms controlling its expression in activated macrophages are not fully understood. Here we report that TRIM59 expression is regulated by Sp1 and Nrf1 in LPS-activated macrophages. TRIM59 is highly expressed in macrophages, and markedly decreased by LPS stimuli in vivo and in vitro. TRIM59 promoter activity is also significantly suppressed by LPS and further analysis demonstrated that Sp1 and Nrf1 directly bound to the proximal promoter of TRIM59 gene. LPS treatment significantly decreased Sp1 expression, nuclear translocation and reduced its binding to the promoter, whereas increased Nrf1 expression, nuclear translocation and enhanced its binding to the promoter. Moreover, LPS-decreased TRIM59 expression was reversed by JNK inhibitor. Finally, TRIM59 level is significantly decreased during atherosclerosis progression. Taken together, our results demonstrated that TRIM59 expression was precisely regulated by Sp1 and Nrf1 in LPS-activated macrophages, which may be dependent on the activation of JNK signaling pathway and TRIM59 may be a potential therapeutic target for inflammatory diseases such as atherosclerosis.
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Shanley KL, Hu CL, Bizzozero OA. Decreased levels of constitutive proteasomes in experimental autoimmune encephalomyelitis may be caused by a combination of subunit displacement and reduced Nfe2l1 expression. J Neurochem 2019; 152:585-601. [PMID: 31709534 DOI: 10.1111/jnc.14912] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 10/31/2019] [Accepted: 11/07/2019] [Indexed: 11/28/2022]
Abstract
The goal of this study was to determine if subunit displacement and/or alterations in proteasome biosynthesis could explain the changes observed in the levels of constitutive proteasomes (c-20S) and immunoproteasomes (i-20S) in the spinal cords of mice with experimental autoimmune encephalomyelitis (EAE). To this end, EAE was induced in C57BL/6 mice by immunization with MOG35-55 peptide. Spinal cords were collected at different times during the disease course and used for western blotting, RNA analysis, and immunohistochemistry. The results show that, as expression of i-20S and the activator PA28 rise in EAE, there is a concomitant decline in that of c-20S at the mRNA and protein level. These changes are observed in neurons and astrocytes but not in oligodendrocytes. The increased amounts of the i-20S-specific subunit β5i and PA28α/β in EAE correlate with the levels of interferon-γ and its downstream effectors p-signal transducer and activator of transcription 1 and interferon regulatory factor-1, but not with those of nuclear factor kappa-light-chain-enhancer of activated B cells. This suggests that the signal transducer and activator of transcription 1/interferon regulatory factor-1 pathway is solely responsible for the induction of these subunits. The decrease in the mRNA and protein levels corresponding to the c-20S-specific subunit β5 may also be due to reduced expression of the nuclear factor (erythroid-derived 2)-like-1 (Nrf1 or Nfe2l1), specifically Nrf1α and Nrf1β. Low Nfe2l1 mRNA expression is unlikely caused by reduced mammalian target of rapamycin signaling but could be the result of diminished pre-B-cell leukemia homeobox-1 transcription factor levels. Together, these findings suggest that a combination of subunit displacement and reduced Nrf1 expression may be responsible for c-20S impairment in EAE. The present work provides insights into the dynamics of proteasome expression in the CNS of EAE mice and is the first to explore Nrf1 signaling in an inflammatory demyelinating disorder.
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Affiliation(s)
- Kara L Shanley
- Department of Cell Biology and Physiology, University of New Mexico - Health Sciences Center, Albuquerque, New Mexico, USA
| | - Che-Lin Hu
- Department of Cell Biology and Physiology, University of New Mexico - Health Sciences Center, Albuquerque, New Mexico, USA
| | - Oscar A Bizzozero
- Department of Cell Biology and Physiology, University of New Mexico - Health Sciences Center, Albuquerque, New Mexico, USA
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Iaconelli J, Ibrahim L, Chen E, Hull M, Schultz PG, Bollong MJ. Small-Molecule Stimulators of NRF1 Transcriptional Activity. Chembiochem 2019; 21:1816-1819. [PMID: 31596542 DOI: 10.1002/cbic.201900487] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 09/25/2019] [Indexed: 01/09/2023]
Abstract
The transcription factor nuclear factor erythroid 2-related factor 1 (NRF1) maintains proteostasis and promotes cellular resilience by stimulating the transcription of proteasomal subunits and a host of protective enzymes. Although NRF1 activation would likely be beneficial in a number of disease states, information regarding its ligandability and upstream regulation are lacking. Herein we report a high-throughput chemical screen that identified selective stimulators of NRF1-driven transcription, including unannotated inhibitors of the ubiquitin proteasome system (UPS) as well as two non-UPS-targeted compounds that synergistically activate NRF1 in the context of submaximal UPS inhibition. This work introduces a suite of tool molecules to study the NRF1 transcriptional response and to uncover the druggable components governing NRF1 activity in cells.
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Affiliation(s)
- Jonathan Iaconelli
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Lara Ibrahim
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Emily Chen
- California Institute for Biomedical Research (Calibr), La Jolla, CA, 92037, USA
| | - Mitchell Hull
- California Institute for Biomedical Research (Calibr), La Jolla, CA, 92037, USA
| | - Peter G Schultz
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Michael J Bollong
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA, 92037, USA
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Marshall RS, Vierstra RD. Dynamic Regulation of the 26S Proteasome: From Synthesis to Degradation. Front Mol Biosci 2019; 6:40. [PMID: 31231659 PMCID: PMC6568242 DOI: 10.3389/fmolb.2019.00040] [Citation(s) in RCA: 143] [Impact Index Per Article: 28.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 05/09/2019] [Indexed: 01/12/2023] Open
Abstract
All eukaryotes rely on selective proteolysis to control the abundance of key regulatory proteins and maintain a healthy and properly functioning proteome. Most of this turnover is catalyzed by the 26S proteasome, an intricate, multi-subunit proteolytic machine. Proteasomes recognize and degrade proteins first marked with one or more chains of poly-ubiquitin, the addition of which is actuated by hundreds of ligases that individually identify appropriate substrates for ubiquitylation. Subsequent proteasomal digestion is essential and influences a myriad of cellular processes in species as diverse as plants, fungi and humans. Importantly, dysfunction of 26S proteasomes is associated with numerous human pathologies and profoundly impacts crop performance, thus making an understanding of proteasome dynamics critically relevant to almost all facets of human health and nutrition. Given this widespread significance, it is not surprising that sophisticated mechanisms have evolved to tightly regulate 26S proteasome assembly, abundance and activity in response to demand, organismal development and stress. These include controls on transcription and chaperone-mediated assembly, influences on proteasome localization and activity by an assortment of binding proteins and post-translational modifications, and ultimately the removal of excess or damaged particles via autophagy. Intriguingly, the autophagic clearance of damaged 26S proteasomes first involves their modification with ubiquitin, thus connecting ubiquitylation and autophagy as key regulatory events in proteasome quality control. This turnover is also influenced by two distinct biomolecular condensates that coalesce in the cytoplasm, one attracting damaged proteasomes for autophagy, and the other reversibly storing proteasomes during carbon starvation to protect them from autophagic clearance. In this review, we describe the current state of knowledge regarding the dynamic regulation of 26S proteasomes at all stages of their life cycle, illustrating how protein degradation through this proteolytic machine is tightly controlled to ensure optimal growth, development and longevity.
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Affiliation(s)
- Richard S Marshall
- Department of Biology, Washington University in St. Louis, St. Louis, MO, United States
| | - Richard D Vierstra
- Department of Biology, Washington University in St. Louis, St. Louis, MO, United States
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67
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Buneeva OA, Medvedev AE. [Ubiquitin-independent protein degradation in proteasomes]. BIOMEDIT︠S︡INSKAI︠A︡ KHIMII︠A︡ 2019; 64:134-148. [PMID: 29723144 DOI: 10.18097/pbmc20186402134] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Proteasomes are large supramolecular protein complexes present in all prokaryotic and eukaryotic cells, where they perform targeted degradation of intracellular proteins. Until recently, it was generally accepted that prior proteolytic degradation in proteasomes the proteins had to be targeted by ubiquitination: the ATP-dependent addition of (typically four sequential) residues of the low-molecular ubiquitin protein, involving the ubiquitin-activating enzyme, ubiquitin-conjugating enzyme and ubiquitin ligase. The cytoplasm and nucleoplasm proteins labeled in this way are then digested in 26S proteasomes. However, in recent years it has become increasingly clear that using this route the cell eliminates only a part of unwanted proteins. Many proteins can be cleaved by the 20S proteasome in an ATP-independent manner and without previous ubiquitination. Ubiquitin-independent protein degradation in proteasomes is a relatively new area of studies of the role of the ubiquitin-proteasome system. However, recent data obtained in this direction already correct existing concepts about proteasomal degradation of proteins and its regulation. Ubiquitin-independent proteasome degradation needs the main structural precondition in proteins: the presence of unstructured regions in the amino acid sequences that provide interaction with the proteasome. Taking into consideration that in humans almost half of all genes encode proteins that contain a certain proportion of intrinsically disordered regions, it appears that the list of proteins undergoing ubiquitin-independent degradation will demonstrate further increase. Since 26S of proteasomes account for only 30% of the total proteasome content in mammalian cells, most of the proteasomes exist in the form of 20S complexes. The latter suggests that ubiquitin-independent proteolysis performed by the 20S proteasome is a natural process of removing damaged proteins from the cell and maintaining a constant level of intrinsically disordered proteins. In this case, the functional overload of proteasomes in aging and/or other types of pathological processes, if it is not accompanied by triggering more radical mechanisms for the elimination of damaged proteins, organelles and whole cells, has the most serious consequences for the whole organism.
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Affiliation(s)
- O A Buneeva
- Institute of Biomedical Chemistry, Moscow, Russia
| | - A E Medvedev
- Institute of Biomedical Chemistry, Moscow, Russia
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68
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Lehrbach NJ, Ruvkun G. Endoplasmic reticulum-associated SKN-1A/Nrf1 mediates a cytoplasmic unfolded protein response and promotes longevity. eLife 2019; 8:44425. [PMID: 30973820 PMCID: PMC6459674 DOI: 10.7554/elife.44425] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 03/29/2019] [Indexed: 01/21/2023] Open
Abstract
Unfolded protein responses (UPRs) safeguard cellular function during proteotoxic stress and aging. In a previous paper (Lehrbach and Ruvkun, 2016) we showed that the ER-associated SKN-1A/Nrf1 transcription factor activates proteasome subunit expression in response to proteasome dysfunction, but it was not established whether SKN-1A/Nrf1 adjusts proteasome capacity in response to other proteotoxic insults. Here, we reveal that misfolded endogenous proteins and the human amyloid beta peptide trigger activation of proteasome subunit expression by SKN-1A/Nrf1. SKN-1A activation is protective against age-dependent defects caused by accumulation of misfolded and aggregation-prone proteins. In a C. elegans Alzheimer’s disease model, SKN-1A/Nrf1 slows accumulation of the amyloid beta peptide and delays adult-onset cellular dysfunction. Our results indicate that SKN-1A surveys cellular protein folding and adjusts proteasome capacity to meet the demands of protein quality control pathways, revealing a new arm of the cytosolic UPR. This regulatory axis is critical for healthy aging and may be a target for therapeutic modulation of human aging and age-related disease.
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Affiliation(s)
- Nicolas J Lehrbach
- Department of Molecular Biology, Massachusetts General Hospital, Boston, United States.,Department of Genetics, Harvard Medical School, Boston, United States
| | - Gary Ruvkun
- Department of Molecular Biology, Massachusetts General Hospital, Boston, United States.,Department of Genetics, Harvard Medical School, Boston, United States
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Qiu L, Wang M, Hu S, Ru X, Ren Y, Zhang Z, Yu S, Zhang Y. Oncogenic Activation of Nrf2, Though as a Master Antioxidant Transcription Factor, Liberated by Specific Knockout of the Full-Length Nrf1α that Acts as a Dominant Tumor Repressor. Cancers (Basel) 2018; 10:cancers10120520. [PMID: 30562963 PMCID: PMC6315801 DOI: 10.3390/cancers10120520] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 12/05/2018] [Accepted: 12/10/2018] [Indexed: 12/12/2022] Open
Abstract
Liver-specific knockout of Nrf1 in the mouse leads to spontaneous development of non- alcoholic steatohepatitis with dyslipidemia, and then its deterioration results in hepatoma, but the underlying mechanism remains elusive to date. A similar pathological model is reconstructed here by using human Nrf1α-specific knockout cell lines. Our evidence has demonstrated that a marked increase of the inflammation marker COX2 definitely occurs in Nrf1α−/− cells. Loss of Nrf1α leads to hyperactivation of Nrf2, which results from substantial decreases in Keap1, PTEN and most of 26S proteasomal subunits in Nrf1α−/− cells. Further investigation of xenograft model mice showed that malignant growth of Nrf1α−/−-derived tumors is almost abolished by silencing of Nrf2, while Nrf1α+/+-tumor is markedly repressed by an inactive mutant (i.e., Nrf2−/−ΔTA), but largely unaffected by a priori constitutive activator (i.e., caNrf2ΔN). Mechanistic studies, combined with transcriptomic sequencing, unraveled a panoramic view of opposing and unifying inter-regulatory cross-talks between Nrf1α and Nrf2 at different layers of the endogenous regulatory networks from multiple signaling towards differential expression profiling of target genes. Collectively, Nrf1α manifests a dominant tumor-suppressive effect by confining Nrf2 oncogenicity. Though as a tumor promoter, Nrf2 can also, in turn, directly activate the transcriptional expression of Nrf1 to form a negative feedback loop. In view of such mutual inter-regulation by between Nrf1α and Nrf2, it should thus be taken severe cautions to interpret the experimental results from loss of Nrf1α, Nrf2 or both.
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Affiliation(s)
- Lu Qiu
- The Laboratory of Cell Biochemistry and Topogenetic Regulation, College of Bioengineering and Faculty of Sciences, Chongqing University, No. 174 Shazheng Street, Shapingba District, Chongqing 400044, China.
| | - Meng Wang
- The Laboratory of Cell Biochemistry and Topogenetic Regulation, College of Bioengineering and Faculty of Sciences, Chongqing University, No. 174 Shazheng Street, Shapingba District, Chongqing 400044, China.
| | - Shaofan Hu
- The Laboratory of Cell Biochemistry and Topogenetic Regulation, College of Bioengineering and Faculty of Sciences, Chongqing University, No. 174 Shazheng Street, Shapingba District, Chongqing 400044, China.
| | - Xufang Ru
- The Laboratory of Cell Biochemistry and Topogenetic Regulation, College of Bioengineering and Faculty of Sciences, Chongqing University, No. 174 Shazheng Street, Shapingba District, Chongqing 400044, China.
| | - Yonggang Ren
- The Laboratory of Cell Biochemistry and Topogenetic Regulation, College of Bioengineering and Faculty of Sciences, Chongqing University, No. 174 Shazheng Street, Shapingba District, Chongqing 400044, China.
| | - Zhengwen Zhang
- Institute of Neuroscience and Psychology, School of Life Sciences, University of Glasgow, 42 Western Common Road, Glasgow G22 5PQ, Scotland, United Kingdom.
| | - Siwang Yu
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, Peking University School of Pharmaceutical Sciences, No. 38 Xueyuan Rd., Haidian District, Beijing 100191, China.
| | - Yiguo Zhang
- The Laboratory of Cell Biochemistry and Topogenetic Regulation, College of Bioengineering and Faculty of Sciences, Chongqing University, No. 174 Shazheng Street, Shapingba District, Chongqing 400044, China.
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70
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Vangala JR, Radhakrishnan SK. Nrf1-mediated transcriptional regulation of the proteasome requires a functional TIP60 complex. J Biol Chem 2018; 294:2036-2045. [PMID: 30559296 DOI: 10.1074/jbc.ra118.006290] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 12/03/2018] [Indexed: 12/15/2022] Open
Abstract
Inhibition of the proteasome leads to proteotoxic stress, which is characterized by the buildup of ubiquitinated proteins that cannot be degraded properly. The transcription factor Nrf1 (also called NFE2L1) counteracts proteotoxic stress by inducing transcription of proteasome subunit genes, resulting in the restoration of proteasome activity. Further understanding of the Nrf1 pathway is therefore of interest in both neurodegeneration, where proteasome activity could be enhanced, and cancer, where suppression of this pathway could potentiate the cell-killing effect mediated by proteasome inhibitor drugs. Here, to identify novel regulators of Nrf1, we performed an RNAi screen in an engineered cell line, reporting on Nrf1 transcriptional activity. In addition to validating known regulators, we discovered that the AAA+ ATPase RUVBL1 is necessary for Nrf1's transcriptional activity. Given that RUVBL1 is part of different multisubunit complexes that play key roles in transcription, we dissected this phenomenon further and found that the TIP60 chromatin-regulatory complex is essential for Nrf1-dependent transcription of proteasome genes. Consistent with these observations, Nrf1, RUVBL1, and TIP60 proteins were co-recruited to the promoter regions of proteasome genes after proteasome inhibitor treatments. More importantly, depletion of RUVBL1 or TIP60 in various cancer cells sensitized them to cell death induced by proteasome inhibition. Overall, our study provides a framework for manipulating the TIP60-Nrf1 axis to alter proteasome function in various human diseases, including cancer.
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Affiliation(s)
- Janakiram R Vangala
- From the Department of Pathology and Massey Cancer Center, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Senthil K Radhakrishnan
- From the Department of Pathology and Massey Cancer Center, Virginia Commonwealth University, Richmond, Virginia 23298
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71
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Xiang Y, Wang M, Hu S, Qiu L, Yang F, Zhang Z, Yu S, Pi J, Zhang Y. Mechanisms controlling the multistage post-translational processing of endogenous Nrf1α/TCF11 proteins to yield distinct isoforms within the coupled positive and negative feedback circuits. Toxicol Appl Pharmacol 2018; 360:212-235. [DOI: 10.1016/j.taap.2018.09.036] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Revised: 09/23/2018] [Accepted: 09/23/2018] [Indexed: 01/20/2023]
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Keller G, Binyamin O, Frid K, Saada A, Gabizon R. Mitochondrial dysfunction in preclinical genetic prion disease: A target for preventive treatment? Neurobiol Dis 2018; 124:57-66. [PMID: 30423473 DOI: 10.1016/j.nbd.2018.11.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 11/09/2018] [Indexed: 12/21/2022] Open
Abstract
Mitochondrial malfunction is a common feature in advanced stages of neurodegenerative conditions, as is the case for the accumulation of aberrantly folded proteins, such as PrP in prion diseases. In this work, we investigated mitochondrial activity and expression of related factors vis a vis PrP accumulation at the subclinical stages of TgMHu2ME199K mice, modeling for genetic prion diseases. While these mice remain healthy until 5-6 months of age, they succumb to fatal disease at 12-14 months. We found that mitochondrial respiratory chain enzymatic activates and ATP/ROS production, were abnormally elevated in asymptomatic mice, concomitant with initial accumulation of disease related PrP. In parallel, the expression of Cytochrome c oxidase (COX) subunit IV isoform 1(Cox IV-1) was reduced and replaced by the activity of Cox IV isoform 2, which operates in oxidative neuronal conditions. At all stages of disease, Cox IV-1 was absent from cells accumulating disease related PrP, suggesting that PrP aggregates may directly compromise normal mitochondrial function. Administration of Nano-PSO, a brain targeted antioxidant, to TgMHu2ME199K mice, reversed functional and biochemical mitochondrial functions to normal conditions regardless of the presence of misfolded PrP. Our results therefore indicate that in genetic prion disease, oxidative damage initiates long before clinical manifestations. These manifest only when aggregated PrP levels are too high for the compensatory mechanisms to sustain mitochondrial activity.
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Affiliation(s)
- Guy Keller
- Department of Neurology, The Agnes Ginges Center for Human Neurogenetics, Israel; Medical School, The Hebrew University, Jerusalem, Israel
| | - Orli Binyamin
- Department of Neurology, The Agnes Ginges Center for Human Neurogenetics, Israel; Medical School, The Hebrew University, Jerusalem, Israel
| | - Kati Frid
- Department of Neurology, The Agnes Ginges Center for Human Neurogenetics, Israel; Medical School, The Hebrew University, Jerusalem, Israel
| | - Ann Saada
- Department of Genetics and Metabolic Diseases, The Monique and Jacques Roboh Department of Genetic Research, Hadassah-Hebrew University Medical Center, Israel; Medical School, The Hebrew University, Jerusalem, Israel
| | - Ruth Gabizon
- Department of Neurology, The Agnes Ginges Center for Human Neurogenetics, Israel; Medical School, The Hebrew University, Jerusalem, Israel.
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73
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Yuan J, Zhang S, Zhang Y. Nrf1 is paved as a new strategic avenue to prevent and treat cancer, neurodegenerative and other diseases. Toxicol Appl Pharmacol 2018; 360:273-283. [PMID: 30267745 DOI: 10.1016/j.taap.2018.09.037] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 09/12/2018] [Accepted: 09/24/2018] [Indexed: 12/21/2022]
Abstract
Transcription factor Nrf1 acts as a unique vital player in maintaining cellular homeostasis and organ integrity during normal development and growth throughout the life process. Loss-of-function of Nrf1 results in severe oxidative stress, genomic instability, embryonic lethality, developmental disorders, and adult diseases such as non-alcoholic steatohepatitis, hepatocellular carcinoma, diabetes and neurogenerative diseases. Thereby, Nrf1 is critically implicated in a variety of important physio-pathological processes by governing robust target genes in order to reinforce antioxidant, detoxification and cytoprotective responses to cellular stress. Notably, there also exists a proteasomal 'bounce-back' response mediated by Nrf1, insofar as to enhance the drug resistance to proteasomal inhibitors in clinical treatment of neuroblastoma, multiple myeloma and triple-negative breast cancers. Recently, several drugs or chemicals are found or re-found in new ways to block the proteasomal compensatory process through inhibiting the multistep processing of Nrf1. Conversely, activation of Nrf1 induced by some drugs or chemicals leads to cytoprotection from cell apoptosis and promotes cell viability. This is the start of constructive and meaningful studies, approaching to explore the mechanism(s) by which Nrf1 is activated to protect neurons and other cells from malignant and degenerative diseases. Overall, Nrf1 has appealed attentions as a new attractive therapeutic strategy for human diseases including cancers.
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Affiliation(s)
- Jianxin Yuan
- Laboratory of Cell Biochemistry and Topogenetic Regulation, College of Bioengineering and Faculty of Sciences, Chongqing University, No. 174 Shazheng Street, Shapingba District, Chongqing 400044, China
| | - Shuwei Zhang
- Laboratory of Cell Biochemistry and Topogenetic Regulation, College of Bioengineering and Faculty of Sciences, Chongqing University, No. 174 Shazheng Street, Shapingba District, Chongqing 400044, China
| | - Yiguo Zhang
- Laboratory of Cell Biochemistry and Topogenetic Regulation, College of Bioengineering and Faculty of Sciences, Chongqing University, No. 174 Shazheng Street, Shapingba District, Chongqing 400044, China.
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74
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O-GlcNAcylation Signal Mediates Proteasome Inhibitor Resistance in Cancer Cells by Stabilizing NRF1. Mol Cell Biol 2018; 38:MCB.00252-18. [PMID: 29941490 PMCID: PMC6094050 DOI: 10.1128/mcb.00252-18] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 06/15/2018] [Indexed: 12/16/2022] Open
Abstract
Cancer cells often heavily depend on the ubiquitin-proteasome system (UPS) for their growth and survival. Irrespective of their strong dependence on the proteasome activity, cancer cells, except for multiple myeloma, are mostly resistant to proteasome inhibitors. Cancer cells often heavily depend on the ubiquitin-proteasome system (UPS) for their growth and survival. Irrespective of their strong dependence on the proteasome activity, cancer cells, except for multiple myeloma, are mostly resistant to proteasome inhibitors. A major cause of this resistance is the proteasome bounce-back response mediated by NRF1, a transcription factor that coordinately activates proteasome subunit genes. To identify new targets for efficient suppression of UPS, we explored, using immunoprecipitation and mass spectrometry, the possible existence of nuclear proteins that cooperate with NRF1 and identified O-linked N-acetylglucosamine transferase (OGT) and host cell factor C1 (HCF-1) as two proteins capable of forming a complex with NRF1. O-GlcNAcylation catalyzed by OGT was essential for NRF1 stabilization and consequent upregulation of proteasome subunit genes. Meta-analysis of breast and colorectal cancers revealed positive correlations in the relative protein abundance of OGT and proteasome subunits. OGT inhibition was effective at sensitizing cancer cells to a proteasome inhibitor both in culture cells and a xenograft mouse model. Since active O-GlcNAcylation is a feature of cancer metabolism, our study has clarified a novel linkage between cancer metabolism and UPS function and added a new regulatory axis to the regulation of the proteasome activity.
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75
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Buneeva OA, Medvedev AE. Ubiquitin-Independent Degradation of Proteins in Proteasomes. BIOCHEMISTRY (MOSCOW), SUPPLEMENT SERIES B: BIOMEDICAL CHEMISTRY 2018. [DOI: 10.1134/s1990750818030022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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76
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6'- O-Galloylpaeoniflorin Attenuates Cerebral Ischemia Reperfusion-Induced Neuroinflammation and Oxidative Stress via PI3K/Akt/Nrf2 Activation. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2018; 2018:8678267. [PMID: 29765506 PMCID: PMC5889897 DOI: 10.1155/2018/8678267] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 11/28/2017] [Accepted: 12/05/2017] [Indexed: 12/27/2022]
Abstract
6'-O-galloylpaeoniflorin (GPF), a galloylated derivative of paeoniflorin isolated from peony root, has been proven to possess antioxidant potential. In this present study, we revealed that GPF treatment exerted significant neuroprotection of PC12 cells following OGD, as evidenced by a reduction of oxidative stress, inflammatory response, cellular injury, and apoptosis in vitro. Furthermore, treatment with GPF increased the levels of phosphorylated Akt (p-Akt) and nuclear factor-erythroid 2-related factor 2 (Nrf2), as well as promoted Nrf2 translocation in PC12 cells, which could be inhibited by Ly294002, an inhibitor of phosphoinositide 3-kinase (PI3K). In addition, Nrf2 knockdown or Ly294002 treatment significantly attenuated the antioxidant, anti-inflammatory, and antiapoptotic activities of GPF in vitro. In vivo studies indicated that GPF treatment significantly reduced infarct volume and improved neurological deficits in rats subjected to CIRI, as well as decreased oxidative stress, inflammation, and apoptosis, which could be inhibited by administration of Ly294002. In conclusion, these results revealed that GPF possesses neuroprotective effects against oxidative stress, inflammation, and apoptosis after ischemia-reperfusion insult via activation of the PI3K/Akt/Nrf2 pathway.
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77
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Fu J, Zheng H, Cui Q, Chen C, Bao S, Sun J, Li L, Yang B, Wang H, Hou Y, Xu Y, Xu Y, Zhang Q, Pi J. Nfe2l1-silenced insulinoma cells acquire aggressiveness and chemoresistance. Endocr Relat Cancer 2018; 25:185-200. [PMID: 29203613 DOI: 10.1530/erc-17-0458] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 12/04/2017] [Indexed: 12/26/2022]
Abstract
The transcription factor nuclear factor erythroid 2-like 1 (NFE2L1 or NRF1) is involved in various critical cell processes such as maintenance of ubiquitin-proteasome system and regulation of the cellular antioxidant response. We previously determined that pancreatic β-cell-specific Nfe2l1-knockout mice had hyperinsulinemia and that silencing of Nfe2l1 in mouse islets or MIN6 insulinoma β-cells induced elevated basal insulin release and altered glucose metabolism. Hypoglycemia is a major issue with aggressive insulinomas, although a role of NFE2L1 in this pathology is not defined. In the present work, we studied the tumorigenicity of Nfe2l1-deficient insulinoma MIN6 cells (Nfe2l1-KD) and sensitivity to chemotherapy. Nfe2l1-KD cells grew faster and were more aggressive than Scramble cells in vitro In a mouse allograft transplantation model, insulinomas arising from Nfe2l1-KD cells were more aggressive and chemoresistant. The conclusion was amplified using streptozotocin (STZ) administration in an allograft transplantation model in diabetic Akita background mice. Furthermore, Nfe2l1-KD cells were resistant to damage by the chemotherapeutic drugs STZ and 5-fluorouracil, which was linked to binding of hexokinase 1 with mitochondria, enhanced mitochondrial membrane potential and closed mitochondrial potential transition pore. Overall, both in vitro and in vivo data from Nfe2l1-KD insulinoma cells provided evidence of a previously un-appreciated action of NFE2L1 in suppression of tumorigenesis. Nfe2l1 silencing desensitizes insulinoma cells and derived tumors to chemotherapeutic-induced damage, likely via metabolic reprograming. These data indicate that NFE2L1 could potentially play an important role in the carcinogenic process and impact chemosensitivity, at least within a subset of pancreatic endocrine tumors.
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Affiliation(s)
- Jingqi Fu
- Program of Environmental ToxicologySchool of Public Health, China Medical University, Shenyang, People's Republic of China
| | - Hongzhi Zheng
- Department of Geriatric EndocrinologyThe First Affiliated Hospital, China Medical University, Shenyang, People's Republic of China
| | - Qi Cui
- Program of Environmental ToxicologySchool of Public Health, China Medical University, Shenyang, People's Republic of China
| | - Chengjie Chen
- Program of Environmental ToxicologySchool of Public Health, China Medical University, Shenyang, People's Republic of China
| | - Simeng Bao
- Program of Environmental ToxicologySchool of Public Health, China Medical University, Shenyang, People's Republic of China
| | - Jing Sun
- Program of Environmental ToxicologySchool of Public Health, China Medical University, Shenyang, People's Republic of China
| | - Lu Li
- Program of Environmental ToxicologySchool of Public Health, China Medical University, Shenyang, People's Republic of China
| | - Bei Yang
- Department of Histology and EmbryologySchool of Basic Medical Sciences, China Medical University, Shenyang, People's Republic of China
| | - Huihui Wang
- Program of Environmental ToxicologySchool of Public Health, China Medical University, Shenyang, People's Republic of China
| | - Yongyong Hou
- Program of Environmental ToxicologySchool of Public Health, China Medical University, Shenyang, People's Republic of China
| | - Yuanyuan Xu
- Program of Environmental ToxicologySchool of Public Health, China Medical University, Shenyang, People's Republic of China
| | - Yuanhong Xu
- Department of Pancreatic SurgeryThe First Affiliated Hospital, China Medical University, Shenyang, People's Republic of China
| | - Qiang Zhang
- Department of Environmental HealthRollins School of Public Health, Emory University, Atlanta, Georgia, USA
| | - Jingbo Pi
- Program of Environmental ToxicologySchool of Public Health, China Medical University, Shenyang, People's Republic of China
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78
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Tomlin F, Gerling-Driessen UIM, Liu YC, Flynn RA, Vangala JR, Lentz CS, Clauder-Muenster S, Jakob P, Mueller WF, Ordoñez-Rueda D, Paulsen M, Matsui N, Foley D, Rafalko A, Suzuki T, Bogyo M, Steinmetz LM, Radhakrishnan SK, Bertozzi CR. Inhibition of NGLY1 Inactivates the Transcription Factor Nrf1 and Potentiates Proteasome Inhibitor Cytotoxicity. ACS CENTRAL SCIENCE 2017; 3:1143-1155. [PMID: 29202016 PMCID: PMC5704294 DOI: 10.1021/acscentsci.7b00224] [Citation(s) in RCA: 127] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Indexed: 05/06/2023]
Abstract
Proteasome inhibitors are used to treat blood cancers such as multiple myeloma (MM) and mantle cell lymphoma. The efficacy of these drugs is frequently undermined by acquired resistance. One mechanism of proteasome inhibitor resistance may involve the transcription factor Nuclear Factor, Erythroid 2 Like 1 (NFE2L1, also referred to as Nrf1), which responds to proteasome insufficiency or pharmacological inhibition by upregulating proteasome subunit gene expression. This "bounce-back" response is achieved through a unique mechanism. Nrf1 is constitutively translocated into the ER lumen, N-glycosylated, and then targeted for proteasomal degradation via the ER-associated degradation (ERAD) pathway. Proteasome inhibition leads to accumulation of cytosolic Nrf1, which is then processed to form the active transcription factor. Here we show that the cytosolic enzyme N-glycanase 1 (NGLY1, the human PNGase) is essential for Nrf1 activation in response to proteasome inhibition. Chemical or genetic disruption of NGLY1 activity results in the accumulation of misprocessed Nrf1 that is largely excluded from the nucleus. Under these conditions, Nrf1 is inactive in regulating proteasome subunit gene expression in response to proteasome inhibition. Through a small molecule screen, we identified a cell-active NGLY1 inhibitor that disrupts the processing and function of Nrf1. The compound potentiates the cytotoxicity of carfilzomib, a clinically used proteasome inhibitor, against MM and T cell-derived acute lymphoblastic leukemia (T-ALL) cell lines. Thus, NGLY1 inhibition prevents Nrf1 activation and represents a new therapeutic approach for cancers that depend on proteasome homeostasis.
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Affiliation(s)
- Frederick
M. Tomlin
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
| | | | - Yi-Chang Liu
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Ryan A. Flynn
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Janakiram R. Vangala
- Department
of Pathology, Virginia Commonwealth University, Richmond, Virginia 23298, United States
| | - Christian S. Lentz
- Department
of Pathology, Stanford University School
of Medicine, 300 Pasteur
Drive, Stanford, California 94305, United States
| | - Sandra Clauder-Muenster
- Genome
Biology Unit, European Molecular Biology
Laboratory (EMBL), 69117 Heidelberg, Germany
| | - Petra Jakob
- Genome
Biology Unit, European Molecular Biology
Laboratory (EMBL), 69117 Heidelberg, Germany
| | - William F. Mueller
- Genome
Biology Unit, European Molecular Biology
Laboratory (EMBL), 69117 Heidelberg, Germany
| | - Diana Ordoñez-Rueda
- Genome
Biology Unit, European Molecular Biology
Laboratory (EMBL), 69117 Heidelberg, Germany
| | - Malte Paulsen
- Genome
Biology Unit, European Molecular Biology
Laboratory (EMBL), 69117 Heidelberg, Germany
| | - Naoko Matsui
- Glycomine,
Inc., 953 Indiana Street, San Francisco, California 94107, United States
| | - Deirdre Foley
- Glycomine,
Inc., 953 Indiana Street, San Francisco, California 94107, United States
| | - Agnes Rafalko
- Glycomine,
Inc., 953 Indiana Street, San Francisco, California 94107, United States
| | - Tadashi Suzuki
- Glycometabolome
Team, Systems Glycobiology Research Group, RIKEN Global Research Cluster, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Matthew Bogyo
- Department
of Pathology, Stanford University School
of Medicine, 300 Pasteur
Drive, Stanford, California 94305, United States
- Department
of Microbiology and Immunology, Stanford
University School of Medicine, 300 Pasteur Drive, Stanford, California 94305, United States
| | - Lars M. Steinmetz
- Genome
Biology Unit, European Molecular Biology
Laboratory (EMBL), 69117 Heidelberg, Germany
- Department
of Genetics, School of Medicine, Stanford
University, Stanford, California 94305, United States
| | - Senthil K. Radhakrishnan
- Department
of Pathology, Virginia Commonwealth University, Richmond, Virginia 23298, United States
| | - Carolyn R. Bertozzi
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
- Howard
Hughes Medical Institute, Chevy
Chase, Maryland 20815, United States
- E-mail:
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79
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Sollinger C, Lillis J, Malik J, Getman M, Proschel C, Steiner L. Erythropoietin Signaling Regulates Key Epigenetic and Transcription Networks in Fetal Neural Progenitor Cells. Sci Rep 2017; 7:14381. [PMID: 29084993 PMCID: PMC5662632 DOI: 10.1038/s41598-017-14366-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 10/09/2017] [Indexed: 12/11/2022] Open
Abstract
Erythropoietin (EPO) and its receptor are highly expressed in the developing nervous system, and exogenous EPO therapy is potentially neuroprotective, however the epigenetic and transcriptional changes downstream of EPO signaling in neural cells are not well understood. To delineate epigenetic changes associated with EPO signaling, we compared histone H3 lysine 4 dimethylation (H3K4me2) in EPO treated and control fetal neural progenitor cells, identifying 1,150 differentially bound regions. These regions were highly enriched near protein coding genes and had significant overlap with H4Acetylation, a mark of active regulatory elements. Motif analyses and co-occupancy studies revealed a complex regulatory network underlying the differentially bound regions, including previously identified mediators of EPO signaling (STAT5, STAT3), and novel factors such as REST, an epigenetic modifier central to neural differentiation and plasticity, and NRF1, a key regulator of antioxidant response and mitochondrial biogenesis. Global transcriptome analyses on neural tubes isolated from E9.0 EpoR-null and littermate control embryos validated our in vitro findings, further suggesting a role for REST and NRF1 downstream of EPO signaling. These data support a role for EPO in regulating the survival, proliferation, and differentiation of neural progenitor cells, and suggest a basis for its function in neural development and neuroprotection.
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Affiliation(s)
| | - Jacquelyn Lillis
- Functional Genomic Center, University of Rochester, Rochester, New York, USA
| | - Jeffrey Malik
- Department of Pediatrics, University of Rochester, Rochester, New York, USA
| | - Michael Getman
- Department of Pediatrics, University of Rochester, Rochester, New York, USA
| | - Chris Proschel
- Department of Pediatrics, University of Rochester, Rochester, New York, USA.,Department of Biomedical Genetics, University of Rochester, Rochester, New York, USA
| | - Laurie Steiner
- Department of Pediatrics, University of Rochester, Rochester, New York, USA.
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80
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A hypermorphic antioxidant response element is associated with increased MS4A6A expression and Alzheimer's disease. Redox Biol 2017; 14:686-693. [PMID: 29179108 PMCID: PMC5705802 DOI: 10.1016/j.redox.2017.10.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 10/18/2017] [Accepted: 10/25/2017] [Indexed: 12/17/2022] Open
Abstract
Late onset Alzheimer's disease (AD) is a multifactorial disorder, with AD risk influenced by both environmental and genetic factors. Recent genome-wide association studies (GWAS) have identified genetic loci associated with increased risk of developing AD. The MS4A (membrane-spanning 4-domains subfamily A) gene cluster is one of the most significant loci associated with AD risk, and MS4A6A expression is correlated with AD pathology. We identified a single nucleotide polymorphism, rs667897, at the MS4A locus that creates an antioxidant response element and links MS4A6A expression to the stress responsive Cap-n-Collar (CNC) transcription factors NRF1 (encoded by NFE2L1) and NRF2 (encoded by NFE2L2). The risk allele of rs667897 generates a strong CNC binding sequence that is activated by proteostatic stress in an NRF1-dependent manner, and is associated with increased expression of the gene MS4A6A. Together, these findings suggest that the cytoprotective CNC regulatory network aberrantly activates MS4A6A expression and increases AD risk in a subset of the population.
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81
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Han JW, Valdez JL, Ho DV, Lee CS, Kim HM, Wang X, Huang L, Chan JY. Nuclear factor-erythroid-2 related transcription factor-1 (Nrf1) is regulated by O-GlcNAc transferase. Free Radic Biol Med 2017. [PMID: 28625484 DOI: 10.1016/j.freeradbiomed.2017.06.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The Nrf1 (Nuclear factor E2-related factor 1) transcription factor performs a critical role in regulating cellular homeostasis. Using a proteomic approach, we identified Host Cell Factor-1 (HCF1), a co-regulator of transcription, and O-GlcNAc transferase (OGT), the enzyme that mediates protein O-GlcNAcylation, as cellular partners of Nrf1a, an isoform of Nrf1. Nrf1a directly interacts with HCF1 through the HCF1 binding motif (HBM), while interaction with OGT is mediated through HCF1. Overexpression of HCF1 and OGT leads to increased Nrf1a protein stability. Addition of O-GlcNAc decreases ubiquitination and degradation of Nrf1a. Transcriptional activation by Nrf1a is increased by OGT overexpression and treatment with PUGNAc. Together, these data suggest that OGT can act as a regulator of Nrf1a.
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Affiliation(s)
- Jeong Woo Han
- Department of Laboratory Medicine and Pathology, University of California, Irvine, D440 Medical Sciences, Irvine, CA 92697, USA
| | - Joshua L Valdez
- Department of Laboratory Medicine and Pathology, University of California, Irvine, D440 Medical Sciences, Irvine, CA 92697, USA
| | - Daniel V Ho
- Department of Laboratory Medicine and Pathology, University of California, Irvine, D440 Medical Sciences, Irvine, CA 92697, USA
| | - Candy S Lee
- Department of Laboratory Medicine and Pathology, University of California, Irvine, D440 Medical Sciences, Irvine, CA 92697, USA
| | - Hyun Min Kim
- Department of Laboratory Medicine and Pathology, University of California, Irvine, D440 Medical Sciences, Irvine, CA 92697, USA
| | - Xiaorong Wang
- Departments of Physiology and Biophysics, University of California, Irvine, D440 Medical Sciences, Irvine, CA 92697, USA
| | - Lan Huang
- Departments of Physiology and Biophysics, University of California, Irvine, D440 Medical Sciences, Irvine, CA 92697, USA
| | - Jefferson Y Chan
- Department of Laboratory Medicine and Pathology, University of California, Irvine, D440 Medical Sciences, Irvine, CA 92697, USA.
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82
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A Homeostatic Shift Facilitates Endoplasmic Reticulum Proteostasis through Transcriptional Integration of Proteostatic Stress Response Pathways. Mol Cell Biol 2017; 37:MCB.00439-16. [PMID: 27920251 DOI: 10.1128/mcb.00439-16] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 11/23/2016] [Indexed: 01/01/2023] Open
Abstract
Eukaryotic cells maintain protein homeostasis through the activity of multiple basal and inducible systems, which function in concert to allow cells to adapt to a wide range of environmental conditions. Although the transcriptional programs regulating individual pathways have been studied in detail, it is not known how the different pathways are transcriptionally integrated such that a deficiency in one pathway can be compensated by a change in an auxiliary response. One such pathway that plays an essential role in many proteostasis responses is the ubiquitin-proteasome system, which functions to degrade damaged, unfolded, or short half-life proteins. Transcriptional regulation of the proteasome is mediated by the transcription factor Nrf1. Using a conditional knockout mouse model, we found that Nrf1 regulates protein homeostasis in the endoplasmic reticulum (ER) through transcriptional regulation of the ER stress sensor ATF6. In Nrf1 conditional-knockout mice, a reduction in proteasome activity is accompanied by an ATF6-dependent downregulation of the endoplasmic reticulum-associated degradation machinery, which reduces the substrate burden on the proteasome. This indicates that Nrf1 regulates a homeostatic shift through which proteostasis in the endoplasmic reticulum and cytoplasm are coregulated based on a cell's ability to degrade proteins.
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83
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Possible roles of the transcription factor Nrf1 (NFE2L1) in neural homeostasis by regulating the gene expression of deubiquitinating enzymes. Biochem Biophys Res Commun 2017; 484:176-183. [DOI: 10.1016/j.bbrc.2017.01.038] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Accepted: 01/09/2017] [Indexed: 01/01/2023]
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84
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Pajares M, Cuadrado A, Rojo AI. Modulation of proteostasis by transcription factor NRF2 and impact in neurodegenerative diseases. Redox Biol 2017; 11:543-553. [PMID: 28104575 PMCID: PMC5239825 DOI: 10.1016/j.redox.2017.01.006] [Citation(s) in RCA: 135] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 01/04/2017] [Accepted: 01/05/2017] [Indexed: 12/19/2022] Open
Abstract
Neurodegenerative diseases are linked to the accumulation of specific protein aggregates, suggesting an intimate connection between injured brain and loss of proteostasis. Proteostasis refers to all the processes by which cells control the abundance and folding of the proteome thanks to a wide network that integrates the regulation of signaling pathways, gene expression and protein degradation systems. This review attempts to summarize the most relevant findings about the transcriptional modulation of proteostasis exerted by the transcription factor NRF2 (nuclear factor (erythroid-derived 2)-like 2). NRF2 has been classically considered as the master regulator of the antioxidant cell response, although it is currently emerging as a key component of the transduction machinery to maintain proteostasis. As we will discuss, NRF2 could be envisioned as a hub that compiles emergency signals derived from misfolded protein accumulation in order to build a coordinated and perdurable transcriptional response. This is achieved by functions of NRF2 related to the control of genes involved in the maintenance of the endoplasmic reticulum physiology, the proteasome and autophagy.
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Affiliation(s)
- Marta Pajares
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto de Investigación Sanitaria La Paz (IdiPaz), Instituto de Investigaciones Biomédicas Alberto Sols UAM-CSIC, Madrid, Spain; Department of Biochemistry, Faculty of Medicine, Autonomous University of Madrid, Madrid, Spain
| | - Antonio Cuadrado
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto de Investigación Sanitaria La Paz (IdiPaz), Instituto de Investigaciones Biomédicas Alberto Sols UAM-CSIC, Madrid, Spain; Department of Biochemistry, Faculty of Medicine, Autonomous University of Madrid, Madrid, Spain
| | - Ana I Rojo
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto de Investigación Sanitaria La Paz (IdiPaz), Instituto de Investigaciones Biomédicas Alberto Sols UAM-CSIC, Madrid, Spain; Department of Biochemistry, Faculty of Medicine, Autonomous University of Madrid, Madrid, Spain.
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85
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Ciarlone GE, Dean JB. Acute hypercapnic hyperoxia stimulates reactive species production in the caudal solitary complex of rat brain slices but does not induce oxidative stress. Am J Physiol Cell Physiol 2016; 311:C1027-C1039. [DOI: 10.1152/ajpcell.00161.2016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 10/05/2016] [Indexed: 12/28/2022]
Abstract
Central CO2 chemoreceptive neurons in the caudal solitary complex (cSC) are stimulated by hyperoxia via a free radical mechanism. Hyperoxia has been shown to increase superoxide and nitric oxide in the cSC, but it remains unknown how changes in Pco2 during hyperoxia affect the production of O2-dependent reactive oxygen and nitrogen species (RONS) downstream that can lead to increased levels of oxidative and nitrosative stress, cellular excitability, and, potentially, dysfunction. We used real-time fluorescence microscopy in rat brain slices to determine how hyperoxia and hypercapnic acidosis (HA) modulate one another in the production of key RONS, as well as colorimetric assays to measure levels of oxidized and nitrated lipids and proteins. We also examined the effects of CO2 narcosis and hypoxia before euthanasia and brain slice harvesting, as these neurons are CO2 sensitive and hypothesized to employ CO2/H+ mechanisms that exacerbate RONS production and potentially oxidative stress. Our findings show that hyperoxia ± HA increases the production of peroxynitrite and its derivatives, whereas increases in Fenton chemistry are most prominent during hyperoxia + HA. Using CO2 narcosis before euthanasia modulates cellular sensitivity to HA postmortem and enhances the magnitude of the peroxynitrite pathway, but blunts the activity of Fenton chemistry. Overall, hyperoxia and HA do not result in increased production of markers of oxidative and nitrosative stress as expected. We postulate this is due to antioxidant and proteosomal removal of damaged lipids and proteins to maintain cell viability and avoid death during protracted hyperoxia.
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Affiliation(s)
- Geoffrey E. Ciarlone
- Department of Molecular Pharmacology and Physiology, Hyperbaric Biomedical Research Laboratory, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Jay B. Dean
- Department of Molecular Pharmacology and Physiology, Hyperbaric Biomedical Research Laboratory, Morsani College of Medicine, University of South Florida, Tampa, Florida
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86
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Sotzny F, Schormann E, Kühlewindt I, Koch A, Brehm A, Goldbach-Mansky R, Gilling KE, Krüger E. TCF11/Nrf1-Mediated Induction of Proteasome Expression Prevents Cytotoxicity by Rotenone. Antioxid Redox Signal 2016; 25:870-885. [PMID: 27345029 PMCID: PMC6445217 DOI: 10.1089/ars.2015.6539] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
AIMS Precise regulation of cellular protein degradation is essential for maintaining protein and redox homeostasis. The ubiquitin proteasome system (UPS) represents one of the major degradation machineries, and UPS disturbances are strongly associated with neurodegeneration. We have previously shown that the transcription factor TCF11/Nrf1 induces antioxidant response element-mediated upregulation of UPS components in response to proteotoxic stress. Knockout of TCF11/Nrf1 is embryonically lethal, and therefore, the present investigation describes the role of oxidative stress in regulating TCF11/Nrf1-dependent proteasome expression in a model system relevant to Parkinson's disease. RESULTS Using the human dopaminergic neuroblastoma cell line SH-SY5Y and mouse nigrostriatal organotypic slice cultures, gene and protein expression analysis and functional assays revealed oxidative stress is induced by the proteasome inhibitor epoxomicin or the mitochondrial complex I inhibitor rotenone and promotes the upregulation of proteasome expression and function mediated by TCF11/Nrf1 activation. In addition, we show that these stress conditions induce the unfolded protein response. TCF11/Nrf1, thus, has a cytoprotective function in response to oxidative and proteotoxic stress. Innovation and Conclusion: We here demonstrate that adaption of the proteasome system in response to oxidative stress is dependent on TCF11/Nrf1 in this model system. We conclude that TCF11/Nrf1, therefore, plays a vital role in maintaining redox and protein homeostasis. This work provides a vital insight into the molecular mechanisms of neurodegeneration due to oxidative stress by rotenone, and further studies investigating the role of TCF11/Nrf1 in the human condition would be of considerable interest. Antioxid. Redox Signal. 25, 870-885.
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Affiliation(s)
- Franziska Sotzny
- 1 Charité-Universitätsmedizin Berlin, Institut für Biochemie , Berlin, Germany
| | - Eileen Schormann
- 1 Charité-Universitätsmedizin Berlin, Institut für Biochemie , Berlin, Germany
| | - Ina Kühlewindt
- 1 Charité-Universitätsmedizin Berlin, Institut für Biochemie , Berlin, Germany
| | - Annett Koch
- 1 Charité-Universitätsmedizin Berlin, Institut für Biochemie , Berlin, Germany
| | - Anja Brehm
- 1 Charité-Universitätsmedizin Berlin, Institut für Biochemie , Berlin, Germany
| | | | - Kate E Gilling
- 1 Charité-Universitätsmedizin Berlin, Institut für Biochemie , Berlin, Germany
| | - Elke Krüger
- 1 Charité-Universitätsmedizin Berlin, Institut für Biochemie , Berlin, Germany
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87
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Differential roles of NF-Y transcription factor in ER chaperone expression and neuronal maintenance in the CNS. Sci Rep 2016; 6:34575. [PMID: 27687130 PMCID: PMC5043352 DOI: 10.1038/srep34575] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 09/15/2016] [Indexed: 12/20/2022] Open
Abstract
The mammalian central nervous system (CNS) contains various types of neurons with different neuronal functions. In contrast to established roles of cell type-specific transcription factors on neuronal specification and maintenance, whether ubiquitous transcription factors have conserved or differential neuronal function remains uncertain. Here, we revealed that inactivation of a ubiquitous factor NF-Y in different sets of neurons resulted in cell type-specific neuropathologies and gene downregulation in mouse CNS. In striatal and cerebellar neurons, NF-Y inactivation led to ubiquitin/p62 pathologies with downregulation of an endoplasmic reticulum (ER) chaperone Grp94, as we previously observed by NF-Y deletion in cortical neurons. In contrast, NF-Y inactivation in motor neurons induced neuronal loss without obvious protein deposition. Detailed analysis clarified downregulation of another ER chaperone Grp78 in addition to Grp94 in motor neurons, and knockdown of both ER chaperones in motor neurons recapitulated the pathology observed after NF-Y inactivation. Finally, additional downregulation of Grp78 in striatal neurons suppressed ubiquitin accumulation induced by NF-Y inactivation, implying that selective ER chaperone downregulation mediates different neuropathologies. Our data suggest distinct roles of NF-Y in protein homeostasis and neuronal maintenance in the CNS by differential regulation of ER chaperone expression.
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88
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Mendizabal I, Shi L, Keller TE, Konopka G, Preuss TM, Hsieh TF, Hu E, Zhang Z, Su B, Yi SV. Comparative Methylome Analyses Identify Epigenetic Regulatory Loci of Human Brain Evolution. Mol Biol Evol 2016; 33:2947-2959. [PMID: 27563052 PMCID: PMC5062329 DOI: 10.1093/molbev/msw176] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
How do epigenetic modifications change across species and how do these modifications affect evolution? These are fundamental questions at the forefront of our evolutionary epigenomic understanding. Our previous work investigated human and chimpanzee brain methylomes, but it was limited by the lack of outgroup data which is critical for comparative (epi)genomic studies. Here, we compared whole genome DNA methylation maps from brains of humans, chimpanzees and also rhesus macaques (outgroup) to elucidate DNA methylation changes during human brain evolution. Moreover, we validated that our approach is highly robust by further examining 38 human-specific DMRs using targeted deep genomic and bisulfite sequencing in an independent panel of 37 individuals from five primate species. Our unbiased genome-scan identified human brain differentially methylated regions (DMRs), irrespective of their associations with annotated genes. Remarkably, over half of the newly identified DMRs locate in intergenic regions or gene bodies. Nevertheless, their regulatory potential is on par with those of promoter DMRs. An intriguing observation is that DMRs are enriched in active chromatin loops, suggesting human-specific evolutionary remodeling at a higher-order chromatin structure. These findings indicate that there is substantial reprogramming of epigenomic landscapes during human brain evolution involving noncoding regions.
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Affiliation(s)
- Isabel Mendizabal
- School of Biological Sciences, Institute of Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA Department of Genetics, Physical Anthropology and Animal Physiology, University of the Basque Country, Leioa, Spain
| | - Lei Shi
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China The Molecular & Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI
| | - Thomas E Keller
- School of Biological Sciences, Institute of Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA
| | - Genevieve Konopka
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX
| | - Todd M Preuss
- Division of Neuropharmacology and Neurologic Diseases & Center for Translational Social Neuroscience, Department of Pathology and Laboratory Medicine, Yerkes National Primate Research Center, Emory University School of Medicine, Emory University, Atlanta, GA
| | - Tzung-Fu Hsieh
- Department of Plant and Microbial Biology and Plants for Human Health Institute, North Carolina State University, Raleigh, NC
| | - Enzhi Hu
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China Kunming College of Life Science, University of Chinese Academy of Sciences, Beijing, China
| | - Zhe Zhang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
| | - Bing Su
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
| | - Soojin V Yi
- School of Biological Sciences, Institute of Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA
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89
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Molecular and cellular basis for the unique functioning of Nrf1, an indispensable transcription factor for maintaining cell homoeostasis and organ integrity. Biochem J 2016; 473:961-1000. [PMID: 27060105 DOI: 10.1042/bj20151182] [Citation(s) in RCA: 96] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 01/26/2016] [Indexed: 12/30/2022]
Abstract
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.
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Koizumi S, Irie T, Hirayama S, Sakurai Y, Yashiroda H, Naguro I, Ichijo H, Hamazaki J, Murata S. The aspartyl protease DDI2 activates Nrf1 to compensate for proteasome dysfunction. eLife 2016; 5. [PMID: 27528193 PMCID: PMC5001836 DOI: 10.7554/elife.18357] [Citation(s) in RCA: 125] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 08/12/2016] [Indexed: 01/21/2023] Open
Abstract
In response to proteasome dysfunction, mammalian cells upregulate proteasome gene expression by activating Nrf1. Nrf1 is an endoplasmic reticulum-resident transcription factor that is continually retrotranslocated and degraded by the proteasome. Upon proteasome inhibition, Nrf1 escapes degradation and is cleaved to become active. However, the processing enzyme for Nrf1 remains obscure. Here we show that the aspartyl protease DNA-damage inducible 1 homolog 2 (DDI2) is required to cleave and activate Nrf1. Deletion of DDI2 reduced the cleaved form of Nrf1 and increased the full-length cytosolic form of Nrf1, resulting in poor upregulation of proteasomes in response to proteasome inhibition. These defects were restored by adding back wild-type DDI2 but not protease-defective DDI2. Our results provide a clue for blocking compensatory proteasome synthesis to improve cancer therapies targeting proteasomes. DOI:http://dx.doi.org/10.7554/eLife.18357.001 The proteasome is a machine that destroys unnecessary or damaged proteins inside cells. This role of the proteasome is essential for cell survival, and so when the proteasome is inhibited, cells produce new proteasomes to compensate. Upon proteasome inhibition, a protein called Nrf1 is activated and executes this “bounce-back” response. Some cancer treatments aim to kill cancer cells by inhibiting proteasomes, but these treatments may be unsuccessful if the bounce-back response is not also prevented. Therefore, understanding how Nrf1 is activated is an important issue. Nrf1 is produced at a structure called the endoplasmic reticulum in cells and is continually destroyed by the proteasome. On the other hand, when proteasomes are inhibited, Nrf1 accumulates and is cleaved into an active form, which moves to the cell nucleus to start producing proteasomes. However, it was not known which molecule cleaves Nrf1. Koizumi et al. set out to discover this molecule by screening the genetic material of human cells, and identified a gene that encodes a protease (an enzyme that cleaves other proteins) called DDI2. The loss of DDI2 from cells prevented Nrf1 from being cleaved and entering the nucleus, resulting in low levels of proteasome production. Further experiments showed that a mutant form of DDI2 that lacked protease activity was unable to cleave Nrf1, confirming DDI2’s role in activating Nrf1. Deleting DDI2 from cells does not completely prevent the cleavage of Nrf1, and so some other cleaving enzyme might exist; the identity of this enzyme remains to be discovered. Future work is also needed to establish exactly how DDI2 cleaves Nrf1. This could help to develop a DDI2 inhibitor for cancer treatment that could be used in combination with existing proteasome inhibitors. DOI:http://dx.doi.org/10.7554/eLife.18357.002
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Affiliation(s)
- Shun Koizumi
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Taro Irie
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Shoshiro Hirayama
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Yasuyuki Sakurai
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Hideki Yashiroda
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Isao Naguro
- Laboratory of Cell Signaling, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Hidenori Ichijo
- Laboratory of Cell Signaling, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Jun Hamazaki
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Shigeo Murata
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
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91
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Ogunbileje JO, Porter C, Herndon DN, Chao T, Abdelrahman DR, Papadimitriou A, Chondronikola M, Zimmers TA, Reidy PT, Rasmussen BB, Sidossis LS. Hypermetabolism and hypercatabolism of skeletal muscle accompany mitochondrial stress following severe burn trauma. Am J Physiol Endocrinol Metab 2016; 311:E436-48. [PMID: 27382037 PMCID: PMC5005969 DOI: 10.1152/ajpendo.00535.2015] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Accepted: 07/01/2016] [Indexed: 01/11/2023]
Abstract
Burn trauma results in prolonged hypermetabolism and skeletal muscle wasting. How hypermetabolism contributes to muscle wasting in burn patients remains unknown. We hypothesized that oxidative stress, cytosolic protein degradation, and mitochondrial stress as a result of hypermetabolism contribute to muscle cachexia postburn. Patients (n = 14) with burns covering >30% of their total body surface area were studied. Controls (n = 13) were young healthy adults. We found that burn patients were profoundly hypermetabolic at both the skeletal muscle and systemic levels, indicating increased oxygen consumption by mitochondria. In skeletal muscle of burn patients, concurrent activation of mTORC1 signaling and elevation in the fractional synthetic rate paralleled increased levels of proteasomes and elevated fractional breakdown rate. Burn patients had greater levels of oxidative stress markers as well as higher expression of mtUPR-related genes and proteins, suggesting that burns increased mitochondrial stress and protein damage. Indeed, upregulation of cytoprotective genes suggests hypermetabolism-induced oxidative stress postburn. In parallel to mtUPR activation postburn, mitochondrial-specific proteases (LONP1 and CLPP) and mitochondrial translocases (TIM23, TIM17B, and TOM40) were upregulated, suggesting increased mitochondrial protein degradation and transport of preprotein, respectively. Our data demonstrate that proteolysis occurs in both the cytosolic and mitochondrial compartments of skeletal muscle in severely burned patients. Increased mitochondrial protein turnover may be associated with increased protein damage due to hypermetabolism-induced oxidative stress and activation of mtUPR. Our results suggest a novel role for the mitochondria in burn-induced cachexia.
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Affiliation(s)
- John O Ogunbileje
- Metabolism Unit, Shriners Hospitals for Children, Galveston, Texas; Department of Surgery, University of Texas Medical Branch, Galveston, Texas;
| | - Craig Porter
- Metabolism Unit, Shriners Hospitals for Children, Galveston, Texas; Department of Surgery, University of Texas Medical Branch, Galveston, Texas
| | - David N Herndon
- Metabolism Unit, Shriners Hospitals for Children, Galveston, Texas; Department of Surgery, University of Texas Medical Branch, Galveston, Texas
| | - Tony Chao
- Metabolism Unit, Shriners Hospitals for Children, Galveston, Texas; Department of Surgery, University of Texas Medical Branch, Galveston, Texas
| | - Doaa R Abdelrahman
- Metabolism Unit, Shriners Hospitals for Children, Galveston, Texas; Department of Surgery, University of Texas Medical Branch, Galveston, Texas
| | - Anastasia Papadimitriou
- Metabolism Unit, Shriners Hospitals for Children, Galveston, Texas; Department of Nutrition and Metabolism, University of Texas Medical Branch, Galveston, Texas
| | | | - Teresa A Zimmers
- Department of Surgery, Indiana University School of Medicine, Indianapolis, Indiana
| | - Paul T Reidy
- Department of Nutrition and Metabolism, University of Texas Medical Branch, Galveston, Texas
| | - Blake B Rasmussen
- Department of Nutrition and Metabolism, University of Texas Medical Branch, Galveston, Texas
| | - Labros S Sidossis
- Metabolism Unit, Shriners Hospitals for Children, Galveston, Texas; Department of Surgery, University of Texas Medical Branch, Galveston, Texas; Department of Kinesiology and Health, Rutgers University, New Brunswick, New Jersey; and Robert Wood Johnson Medical School, Rutgers University, New Brunswick, New Jersey
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92
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Fukagai K, Waku T, Chowdhury AMMA, Kubo K, Matsumoto M, Kato H, Natsume T, Tsuruta F, Chiba T, Taniguchi H, Kobayashi A. USP15 stabilizes the transcription factor Nrf1 in the nucleus, promoting the proteasome gene expression. Biochem Biophys Res Commun 2016; 478:363-370. [PMID: 27416755 DOI: 10.1016/j.bbrc.2016.07.045] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 07/08/2016] [Indexed: 02/04/2023]
Abstract
The transcriptional factor Nrf1 (NF-E2-related factor 1) sustains protein homeostasis (proteostasis) by regulating the expression of proteasome genes. Under physiological conditions, the transcriptional activity of Nrf1 is repressed by its sequestration into the endoplasmic reticulum (ER) and furthermore by two independent ubiquitin-proteasome pathways, comprising Hrd1 and β-TrCP in the cytoplasm and nucleus, respectively. However, the molecular mechanisms underlying Nrf1 activation remain unclear. Here, we report that USP15 (Ubiquitin-Specific Protease 15) activates Nrf1 in the nucleus by stabilizing it through deubiquitination. We first identified USP15 as an Nrf1-associated factor through proteome analysis. USP15 physically interacts with Nrf1, and it markedly stabilizes Nrf1 by removing its ubiquitin moieties. USP15 activates the Nrf1-mediated expression of a proteasome gene luciferase reporter and endogenous proteasome activity. The siRNA-mediated knockdown of USP15 diminishes the Nrf1-induced proteasome gene expression in response to proteasome inhibition. These results uncover a new regulatory mechanism that USP15 activates Nrf1 against the β-TrCP inhibition to maintain proteostasis.
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Affiliation(s)
- Kousuke Fukagai
- Laboratory for Genetic Code, Graduate School of Life and Medical Sciences, Doshisha University, Kyotanabe, Kyoto, Japan
| | - Tsuyoshi Waku
- Laboratory for Genetic Code, Graduate School of Life and Medical Sciences, Doshisha University, Kyotanabe, Kyoto, Japan
| | - A M Masudul Azad Chowdhury
- Laboratory for Genetic Code, Graduate School of Life and Medical Sciences, Doshisha University, Kyotanabe, Kyoto, Japan
| | - Kaori Kubo
- Laboratory for Genetic Code, Graduate School of Life and Medical Sciences, Doshisha University, Kyotanabe, Kyoto, Japan
| | - Mariko Matsumoto
- Laboratory for Genetic Code, Graduate School of Life and Medical Sciences, Doshisha University, Kyotanabe, Kyoto, Japan
| | - Hiroki Kato
- Laboratory for Genetic Code, Graduate School of Life and Medical Sciences, Doshisha University, Kyotanabe, Kyoto, Japan
| | - Tohru Natsume
- National Institutes of Advanced Industrial Science and Technology, Biological Information Research Center (JBIRC), Tokyo, Japan
| | - Fuminori Tsuruta
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Tomoki Chiba
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Hiroaki Taniguchi
- Laboratory for Genetic Code, Graduate School of Life and Medical Sciences, Doshisha University, Kyotanabe, Kyoto, Japan
| | - Akira Kobayashi
- Laboratory for Genetic Code, Graduate School of Life and Medical Sciences, Doshisha University, Kyotanabe, Kyoto, Japan.
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93
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TALENs-directed knockout of the full-length transcription factor Nrf1α that represses malignant behaviour of human hepatocellular carcinoma (HepG2) cells. Sci Rep 2016; 6:23775. [PMID: 27065079 PMCID: PMC4827396 DOI: 10.1038/srep23775] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 03/14/2016] [Indexed: 02/07/2023] Open
Abstract
The full-length Nrf1α is processed into distinct isoforms, which together regulate genes essential for maintaining cellular homeostasis and organ integrity, and liver-specific loss of Nrf1 in mice results in spontaneous hepatoma. Herein, we report that the human constitutive Nrf1α, rather than smaller Nrf1β/γ, expression is attenuated or abolished in the case of low-differentiated high-metastatic hepatocellular carcinomas. Therefore, Nrf1α is of importance in the physio-pathological origin and development, but its specific pathobiological function(s) remains elusive. To address this, TALENs-directed knockout of Nrf1α, but not Nrf1β/γ, is created in the human hepatocellular carcinoma (HepG2) cells. The resulting Nrf1α−/− cells are elongated, with slender spindle-shapes and enlarged gaps between cells observed under scanning electron microscope. When compared with wild-type controls, the invasive and migratory abilities of Nrf1α−/− cells are increased significantly, along with the cell-cycle G2-M arrest and S-phase reduction, as accompanied by suppressed apoptosis. Despite a modest increase in the soft-agar colony formation of Nrf1α−/− cells, its loss-of-function markedly promotes malgrowth of the subcutaneous carcinoma xenograft in nude mice with hepatic metastasis. Together with molecular expression results, we thus suppose requirement of Nrf1α (and major derivates) for gene regulatory mechanisms repressing cancer cell process (e.g. EMT) and malignant behaviour (e.g. migration).
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94
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Small Maf proteins (MafF, MafG, MafK): History, structure and function. Gene 2016; 586:197-205. [PMID: 27058431 DOI: 10.1016/j.gene.2016.03.058] [Citation(s) in RCA: 165] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 03/11/2016] [Accepted: 03/30/2016] [Indexed: 12/12/2022]
Abstract
The small Maf proteins (sMafs) are basic region leucine zipper (bZIP)-type transcription factors. The basic region of the Maf family is unique among the bZIP factors, and it contributes to the distinct DNA-binding mode of this class of proteins. MafF, MafG and MafK are the three vertebrate sMafs, and no functional differences have been observed among them in terms of their bZIP structures. sMafs form homodimers by themselves, and they form heterodimers with cap 'n' collar (CNC) proteins (p45 NF-E2, Nrf1, Nrf2, and Nrf3) and also with Bach proteins (Bach1 and Bach2). Because CNC and Bach proteins cannot bind to DNA as monomers, sMafs are indispensable partners that are required by CNC and Bach proteins to exert their functions. sMafs lack the transcriptional activation domain; hence, their homodimers act as transcriptional repressors. In contrast, sMafs participate in transcriptional activation or repression depending on their heterodimeric partner molecules and context. Mouse genetic analyses have revealed that various biological pathways are under the regulation of CNC-sMaf heterodimers. In this review, we summarize the history and current progress of sMaf studies in relation to their partners.
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95
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Kim HM, Han JW, Chan JY. Nuclear Factor Erythroid-2 Like 1 (NFE2L1): Structure, function and regulation. Gene 2016; 584:17-25. [PMID: 26947393 DOI: 10.1016/j.gene.2016.03.002] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 02/18/2016] [Accepted: 03/01/2016] [Indexed: 02/06/2023]
Abstract
Nrf1 (also referred to as NFE2L1) is a member of the CNC-bZIP family of transcription factors that are characterized by a highly conserved CNC-domain, and a basic-leucine zipper domain required for dimerization and DNA binding. Nrf1 is ubiquitously expressed across tissue and cell types as various isoforms, and is induced by stress signals from a broad spectrum of stimuli. Evidence indicates that Nrf1 plays an important role in regulating a range of cellular functions including oxidative stress response, differentiation, inflammatory response, metabolism, and maintaining proteostasis. Thus, Nrf1 has been implicated in the pathogenesis of various disease processes including cancer development, and degenerative and metabolic disorders. This review summarizes our current understanding of Nrf1 and the molecular mechanism underlying its regulation and action in different cellular functions.
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Affiliation(s)
- Hyun Min Kim
- Department of Laboratory Medicine and Pathology, University of California, Irvine, D440 Medical Sciences, Irvine, CA 92697, USA
| | - Jeong Woo Han
- Department of Laboratory Medicine and Pathology, University of California, Irvine, D440 Medical Sciences, Irvine, CA 92697, USA
| | - Jefferson Y Chan
- Department of Laboratory Medicine and Pathology, University of California, Irvine, D440 Medical Sciences, Irvine, CA 92697, USA.
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96
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Yamanaka T, Tosaki A, Kurosawa M, Shimogori T, Hattori N, Nukina N. Genome-wide analyses in neuronal cells reveal that upstream transcription factors regulate lysosomal gene expression. FEBS J 2016; 283:1077-87. [DOI: 10.1111/febs.13650] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 12/17/2015] [Accepted: 01/08/2016] [Indexed: 12/01/2022]
Affiliation(s)
- Tomoyuki Yamanaka
- Laboratory of Structural Neuropathology; Doshisha University Graduate School of Brain Science; Kyoto Japan
- Laboratory for Structural Neuropathology; RIKEN Brain Science Institute; Saitama Japan
- Department of Neuroscience for Neurodegenerative Disorders; Juntendo University Graduate School of Medicine; Tokyo Japan
- Laboratory for Molecular Mechanisms of Thalamus Development; RIKEN Brain Science Institute; Saitama Japan
| | - Asako Tosaki
- Laboratory for Structural Neuropathology; RIKEN Brain Science Institute; Saitama Japan
| | - Masaru Kurosawa
- Laboratory for Structural Neuropathology; RIKEN Brain Science Institute; Saitama Japan
- Department of Neuroscience for Neurodegenerative Disorders; Juntendo University Graduate School of Medicine; Tokyo Japan
| | - Tomomi Shimogori
- Laboratory for Molecular Mechanisms of Thalamus Development; RIKEN Brain Science Institute; Saitama Japan
| | - Nobutaka Hattori
- Department of Neurology; Juntendo University Graduate School of Medicine; Tokyo Japan
| | - Nobuyuki Nukina
- Laboratory of Structural Neuropathology; Doshisha University Graduate School of Brain Science; Kyoto Japan
- Laboratory for Structural Neuropathology; RIKEN Brain Science Institute; Saitama Japan
- Department of Neuroscience for Neurodegenerative Disorders; Juntendo University Graduate School of Medicine; Tokyo Japan
- Laboratory for Molecular Mechanisms of Thalamus Development; RIKEN Brain Science Institute; Saitama Japan
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97
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Papaevgeniou N, Chondrogianni N. UPS Activation in the Battle Against Aging and Aggregation-Related Diseases: An Extended Review. Methods Mol Biol 2016; 1449:1-70. [PMID: 27613027 DOI: 10.1007/978-1-4939-3756-1_1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Aging is a biological process accompanied by gradual increase of damage in all cellular macromolecules, i.e., nucleic acids, lipids, and proteins. When the proteostasis network (chaperones and proteolytic systems) cannot reverse the damage load due to its excess as compared to cellular repair/regeneration capacity, failure of homeostasis is established. This failure is a major hallmark of aging and/or aggregation-related diseases. Dysfunction of the major cellular proteolytic machineries, namely the proteasome and the lysosome, has been reported during the progression of aging and aggregation-prone diseases. Therefore, activation of these pathways is considered as a possible preventive or therapeutic approach against the progression of these processes. This chapter focuses on UPS activation studies in cellular and organismal models and the effects of such activation on aging, longevity and disease prevention or reversal.
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Affiliation(s)
- Nikoletta Papaevgeniou
- Institute of Biology, Medicinal Chemistry and Biotechnology, National Hellenic Research Foundation, 48 Vassileos Constantinou Ave., Athens, 11635, Greece
| | - Niki Chondrogianni
- Institute of Biology, Medicinal Chemistry and Biotechnology, National Hellenic Research Foundation, 48 Vassileos Constantinou Ave., Athens, 11635, Greece.
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98
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Joyce PI, Fratta P, Landman AS, Mcgoldrick P, Wackerhage H, Groves M, Busam BS, Galino J, Corrochano S, Beskina OA, Esapa C, Ryder E, Carter S, Stewart M, Codner G, Hilton H, Teboul L, Tucker J, Lionikas A, Estabel J, Ramirez-Solis R, White JK, Brandner S, Plagnol V, Bennet DLH, Abramov AY, Greensmith L, Fisher EMC, Acevedo-Arozena A. Deficiency of the zinc finger protein ZFP106 causes motor and sensory neurodegeneration. Hum Mol Genet 2015; 25:291-307. [PMID: 26604141 PMCID: PMC4706115 DOI: 10.1093/hmg/ddv471] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 11/11/2015] [Indexed: 12/12/2022] Open
Abstract
Zinc finger motifs are distributed amongst many eukaryotic protein families, directing nucleic acid–protein and protein–protein interactions. Zinc finger protein 106 (ZFP106) has previously been associated with roles in immune response, muscle differentiation, testes development and DNA damage, although little is known about its specific function. To further investigate the function of ZFP106, we performed an in-depth characterization of Zfp106 deficient mice (Zfp106−/−), and we report a novel role for ZFP106 in motor and sensory neuronal maintenance and survival. Zfp106−/− mice develop severe motor abnormalities, major deficits in muscle strength and histopathological changes in muscle. Intriguingly, despite being highly expressed throughout the central nervous system, Zfp106−/− mice undergo selective motor and sensory neuronal and axonal degeneration specific to the spinal cord and peripheral nervous system. Neurodegeneration does not occur during development of Zfp106−/− mice, suggesting that ZFP106 is likely required for the maintenance of mature peripheral motor and sensory neurons. Analysis of embryonic Zfp106−/− motor neurons revealed deficits in mitochondrial function, with an inhibition of Complex I within the mitochondrial electron transport chain. Our results highlight a vital role for ZFP106 in sensory and motor neuron maintenance and reveal a novel player in mitochondrial dysfunction and neurodegeneration.
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Affiliation(s)
- Peter I Joyce
- MRC Mammalian Genetics Unit, Harwell, Oxfordshire OX11 0RD, UK
| | - Pietro Fratta
- UCL Institute of Neurology and MRC Centre for Neuromuscular Disease, Queen Square, London WC1N 3BG, UK
| | | | - Philip Mcgoldrick
- UCL Institute of Neurology and MRC Centre for Neuromuscular Disease, Queen Square, London WC1N 3BG, UK
| | | | - Michael Groves
- UCL Institute of Neurology and MRC Centre for Neuromuscular Disease, Queen Square, London WC1N 3BG, UK
| | | | - Jorge Galino
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK
| | | | - Olga A Beskina
- UCL Institute of Neurology and MRC Centre for Neuromuscular Disease, Queen Square, London WC1N 3BG, UK
| | | | - Edward Ryder
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK
| | - Sarah Carter
- MRC Mammalian Genetics Unit, Harwell, Oxfordshire OX11 0RD, UK
| | | | - Gemma Codner
- MRC Mammalian Genetics Unit, Harwell, Oxfordshire OX11 0RD, UK
| | - Helen Hilton
- MRC Mammalian Genetics Unit, Harwell, Oxfordshire OX11 0RD, UK
| | - Lydia Teboul
- MRC Mammalian Genetics Unit, Harwell, Oxfordshire OX11 0RD, UK
| | - Jennifer Tucker
- MRC Mammalian Genetics Unit, Harwell, Oxfordshire OX11 0RD, UK
| | | | - Jeanne Estabel
- Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridgeshire CB10 1SA, UK and
| | - Ramiro Ramirez-Solis
- Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridgeshire CB10 1SA, UK and
| | - Jacqueline K White
- Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridgeshire CB10 1SA, UK and
| | - Sebastian Brandner
- UCL Institute of Neurology and MRC Centre for Neuromuscular Disease, Queen Square, London WC1N 3BG, UK
| | | | - David L H Bennet
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK
| | - Andrey Y Abramov
- UCL Institute of Neurology and MRC Centre for Neuromuscular Disease, Queen Square, London WC1N 3BG, UK
| | - Linda Greensmith
- UCL Institute of Neurology and MRC Centre for Neuromuscular Disease, Queen Square, London WC1N 3BG, UK,
| | - Elizabeth M C Fisher
- UCL Institute of Neurology and MRC Centre for Neuromuscular Disease, Queen Square, London WC1N 3BG, UK,
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99
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Zhang Y, Li S, Xiang Y, Qiu L, Zhao H, Hayes JD. The selective post-translational processing of transcription factor Nrf1 yields distinct isoforms that dictate its ability to differentially regulate gene expression. Sci Rep 2015; 5:12983. [PMID: 26268886 PMCID: PMC4534795 DOI: 10.1038/srep12983] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Accepted: 07/13/2015] [Indexed: 12/20/2022] Open
Abstract
Upon translation, the N-terminal homology box 1 (NHB1) signal anchor sequence of Nrf1 integrates it within the endoplasmic reticulum (ER) whilst its transactivation domains [TADs, including acidic domain 1 (AD1), the flanking Asn/Ser/Thr-rich (NST) domain and AD2] are transiently translocated into the ER lumen, whereupon the NST domain is glycosylated to yield an inactive 120-kDa glycoprotein. Subsequently, these TADs are retrotranslocated into extra-luminal subcellular compartments, where Nrf1 is deglycosylated to yield an active 95-kDa isoform. Herein, we report that AD1 and AD2 are required for the stability of the 120-kDa Nrf1 glycoprotein, but not that of the non-glycosylated/de-glycosylated 95-kDa isoform. Degrons within AD1 do not promote proteolytic degradation of the 120-kDa Nrf1 glycoprotein. However, repositioning of AD2-adjoining degrons (i.e. DSGLS-containing SDS1 and PEST2 sequences) into the cyto/nucleoplasm enables selective topovectorial processing of Nrf1 by the proteasome and/or calpains to generate a cleaved active 85-kDa Nrf1 or a dominant-negative 36-kDa Nrf1γ. Production of Nrf1γ is abolished by removal of SDS1 or PEST2 degrons, whereas production of the cleaved 85-kDa Nrf1 is blocked by deletion of the ER luminal-anchoring NHB2 sequence (aa 81–106). Importantly, Nrf1 activity is positively and/or negatively regulated by distinct doses of proteasome and calpain inhibitors.
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Affiliation(s)
- Yiguo Zhang
- 1] The NSFC-funded Laboratory of Cell Biochemistry and Gene Regulation, College of Medical Bioengineering and Faculty of Life Sciences, Chongqing University, No. 174 Shazheng Street, Shapingba District, Chongqing 400044, China [2] Jacqui Wood Cancer Centre, James Arrott Drive, Division of Cancer Research, Medical Research Institute, Ninewells Hospital &Medical School, University of Dundee, DD1 9SY, Scotland, UK
| | - Shaojun Li
- The NSFC-funded Laboratory of Cell Biochemistry and Gene Regulation, College of Medical Bioengineering and Faculty of Life Sciences, Chongqing University, No. 174 Shazheng Street, Shapingba District, Chongqing 400044, China
| | - Yuancai Xiang
- The NSFC-funded Laboratory of Cell Biochemistry and Gene Regulation, College of Medical Bioengineering and Faculty of Life Sciences, Chongqing University, No. 174 Shazheng Street, Shapingba District, Chongqing 400044, China
| | - Lu Qiu
- The NSFC-funded Laboratory of Cell Biochemistry and Gene Regulation, College of Medical Bioengineering and Faculty of Life Sciences, Chongqing University, No. 174 Shazheng Street, Shapingba District, Chongqing 400044, China
| | - Huakan Zhao
- The NSFC-funded Laboratory of Cell Biochemistry and Gene Regulation, College of Medical Bioengineering and Faculty of Life Sciences, Chongqing University, No. 174 Shazheng Street, Shapingba District, Chongqing 400044, China
| | - John D Hayes
- Jacqui Wood Cancer Centre, James Arrott Drive, Division of Cancer Research, Medical Research Institute, Ninewells Hospital &Medical School, University of Dundee, DD1 9SY, Scotland, UK
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100
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Changing gears in Nrf1 research, from mechanisms of regulation to its role in disease and prevention. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2015; 1849:1260-76. [PMID: 26254094 DOI: 10.1016/j.bbagrm.2015.08.001] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 07/02/2015] [Accepted: 08/03/2015] [Indexed: 12/12/2022]
Abstract
The "cap'n'collar" bZIP transcription factor Nrf1 heterodimerizes with small Maf proteins to bind to the Antioxidant Response Element/Electrophile Response Element to transactivate antioxidant enzyme, phase 2 detoxification enzyme and proteasome subunit gene expression. Nrf1 specifically regulates pathways in lipid metabolism, amino acid metabolism, proteasomal degradation, the citric acid cycle, and the mitochondrial respiratory chain. Nrf1 is maintained in the endoplasmic reticulum (ER) in an inactive glycosylated state. Activation involves retrotranslocation from the ER lumen to the cytoplasm, deglycosylation and partial proteolytic processing to generate the active forms of Nrf1. Recent evidence has revealed how this factor is regulated and its involvement in various metabolic diseases. This review outlines Nrf1 structure, function, regulation and its links to insulin resistance, diabetes and inflammation. The glycosylation/deglycosylation of Nrf1 is controlled by glucose levels. Nrf1 glycosylation affects its control of glucose transport, glycolysis, gluconeogenesis and lipid metabolism.
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