1
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Feng D, Qu L, Powell-Coffman JA. Whole genome profiling of short-term hypoxia induced genes and identification of HIF-1 binding sites provide insights into HIF-1 function in Caenorhabditis elegans. PLoS One 2024; 19:e0295094. [PMID: 38743782 PMCID: PMC11093353 DOI: 10.1371/journal.pone.0295094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 04/23/2024] [Indexed: 05/16/2024] Open
Abstract
Oxygen is essential to all the aerobic organisms. However, during normal development, disease and homeostasis, organisms are often challenged by hypoxia (oxygen deprivation). Hypoxia-inducible transcription factors (HIFs) are master regulators of hypoxia response and are evolutionarily conserved in metazoans. The homolog of HIF in the genetic model organism C. elegans is HIF-1. In this study, we aimed to understand short-term hypoxia response to identify HIF-1 downstream genes and identify HIF-1 direct targets in C. elegans. The central research questions were: (1) which genes are differentially expressed in response to short-term hypoxia? (2) Which of these changes in gene expression are dependent upon HIF-1 function? (3) Are any of these hif-1-dependent genes essential to survival in hypoxia? (4) Which genes are the direct targets of HIF-1? We combine whole genome gene expression analyses and chromatin immunoprecipitation sequencing (ChIP-seq) experiments to address these questions. In agreement with other published studies, we report that HIF-1-dependent hypoxia-responsive genes are involved in metabolism and stress response. Some HIF-1-dependent hypoxia-responsive genes like efk-1 and phy-2 dramatically impact survival in hypoxic conditions. Genes regulated by HIF-1 and hypoxia overlap with genes responsive to hydrogen sulfide, also overlap with genes regulated by DAF-16. The genomic regions that co-immunoprecipitate with HIF-1 are strongly enriched for genes involved in stress response. Further, some of these potential HIF-1 direct targets are differentially expressed under short-term hypoxia or are differentially regulated by mutations that enhance HIF-1 activity.
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Affiliation(s)
- Dingxia Feng
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, United States of America
| | - Long Qu
- Department of Statistics, Iowa State University, Ames, Iowa, United States of America
| | - Jo Anne Powell-Coffman
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, United States of America
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2
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Feng D, Qu L, Powell-Coffman JA. Transcriptome analyses describe the consequences of persistent HIF-1 over-activation in Caenorhabditis elegans. PLoS One 2024; 19:e0295093. [PMID: 38517909 PMCID: PMC10959373 DOI: 10.1371/journal.pone.0295093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 02/20/2024] [Indexed: 03/24/2024] Open
Abstract
Metazoan animals rely on oxygen for survival, but during normal development and homeostasis, animals are often challenged by hypoxia (low oxygen). In metazoans, many of the critical hypoxia responses are mediated by the evolutionarily conserved hypoxia-inducible transcription factors (HIFs). The stability and activity of HIF complexes are strictly regulated. In the model organism C. elegans, HIF-1 stability and activity are negatively regulated by VHL-1, EGL-9, RHY-1 and SWAN-1. Importantly, C. elegans mutants carrying strong loss-of-function mutations in these genes are viable, and this provides opportunities to interrogate the molecular consequences of persistent HIF-1 over-activation. We find that the genome-wide gene expression patterns are compellingly similar in these mutants, supporting models in which RHY-1, VHL-1 and EGL-9 function in common pathway(s) to regulate HIF-1 activity. These studies illuminate the diversified biological roles played by HIF-1, including metabolism and stress response. Genes regulated by persistent HIF-1 over-activation overlap with genes responsive to pathogens, and they overlap with genes regulated by DAF-16. As crucial stress regulators, HIF-1 and DAF-16 converge on key stress-responsive genes and function synergistically to enable hypoxia survival.
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Affiliation(s)
- Dingxia Feng
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, United States of America
| | - Long Qu
- Department of Statistics, Iowa State University, Ames, Iowa, United States of America
| | - Jo Anne Powell-Coffman
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, United States of America
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3
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Franziscus CA, Ritz D, Kappel NC, Solinger JA, Schmidt A, Spang A. The protein tyrosine phosphatase PPH-7 is required for fertility and embryonic development in C. elegans at elevated temperatures. FEBS Open Bio 2024; 14:390-409. [PMID: 38320757 PMCID: PMC10909979 DOI: 10.1002/2211-5463.13771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 01/09/2024] [Accepted: 01/19/2024] [Indexed: 03/05/2024] Open
Abstract
Post-translational modifications are key in the regulation of activity, structure, localization, and stability of most proteins in eukaryotes. Phosphorylation is potentially the most studied post-translational modification, also due to its reversibility and thereby the regulatory role this modification often plays. While most research attention was focused on kinases in the past, phosphatases remain understudied, most probably because the addition and presence of the modification is more easily studied than its removal and absence. Here, we report the identification of an uncharacterized protein tyrosine phosphatase PPH-7 in C. elegans, a member of the evolutionary conserved PTPN family of phosphatases. Lack of PPH-7 function led to reduction of fertility and embryonic lethality at elevated temperatures. Proteomics revealed changes in the regulation of targets of the von Hippel-Lindau (VHL) E3 ligase, suggesting a potential role for PPH-7 in the regulation of VHL.
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Affiliation(s)
| | | | | | | | | | - Anne Spang
- BiozentrumUniversity of BaselSwitzerland
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4
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Feng D, Qu L. Transcriptome analyses describe the consequences of persistent HIF-1 over-activation in Caenorhabditis elegans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.15.567311. [PMID: 38014086 PMCID: PMC10680707 DOI: 10.1101/2023.11.15.567311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Metazoan animals rely on oxygen for survival, but during normal development and homeostasis, animals are often challenged by hypoxia (low oxygen). In metazoans, many of the critical hypoxia responses are mediated by the evolutionarily conserved hypoxia-inducible transcription factors (HIFs). The stability and activity of HIF complexes are strictly regulated. In the model organism C. elegans, HIF-1 stability and activity are negatively regulated by VHL-1, EGL-9, RHY-1 and SWAN-1. Importantly, C. elegans mutants carrying strong loss-of-function mutations in these genes are viable, and this provides opportunities to interrogate the molecular consequences of persistent HIF-1 over-activation. We find that the genome-wide gene expression patterns are compellingly similar in these mutants, supporting models in which RHY-1, SWAN-1 and EGL-9 function in common pathway(s) to regulate HIF-1 activity. These studies illuminate the diversified biological roles played by HIF-1, including metabolism, hypoxia and other stress responses, reproduction and development. Genes regulated by persistent HIF-1 over-activation overlap with genes responsive to pathogens, and they overlap with genes regulated by DAF-16. As crucial stress regulators, HIF-1 and DAF-16 converge on key stress-responsive genes and function synergistically to enable hypoxia survival.
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Affiliation(s)
- Dingxia Feng
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, United States of America
| | - Long Qu
- Department of Statistics, Iowa State University, Ames, Iowa, United States of America
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5
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Feng D, Qu L. Whole genome profiling of short-term hypoxia induced genes and identification of HIF-1 binding sites provide insights into HIF-1 function in Caenorhabditis elegans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.15.567310. [PMID: 38014054 PMCID: PMC10680714 DOI: 10.1101/2023.11.15.567310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Oxygen is essential to all the aerobic organisms. However, during normal development, disease and homeostasis, organisms are often challenged by hypoxia (oxygen deprivation). Hypoxia-inducible transcription factors (HIFs) are master regulators of hypoxia response and are evolutionarily conserved in metazoans. The homolog of HIF in the genetic model organism C. elegans is HIF-1. In this study, we aimed to understand short-term hypoxia response and to identify HIF-1 direct targets in C. elegans. The central research questions were: (1) which genes are differentially expressed in response to short-term hypoxia? (2) Which of these changes in gene expression are dependent upon HIF-1 function? (3) How do HIF-1-dependent hypoxia-responsive genes affect hypoxia adaptation? (4) Which genes are the direct targets of HIF-1? We combine whole genome gene expression analyses and chromatin immunoprecipitation sequencing (ChIP-seq) experiments to address these questions. In agreement with other published studies, we report that HIF-1-dependent hypoxia-responsive genes are involved in metabolism, oxidation-reduction process, and stress response. Some HIF-1-dependent hypoxia-responsive genes like efk-1 andphy-2 dramatically impact survival in hypoxic conditions. HIF-1 co-immunoprecipitates with genomic regions proximal genes involved in stress response, protein processing in endoplasmic reticulum, and cell recognition. Further, some of these potential HIF-1 direct targets are differentially expressed under short-term hypoxia or are differentially regulated by mutations that enhance HIF-1 activity.
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Affiliation(s)
- Dingxia Feng
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, United States of America
| | - Long Qu
- Department of Statistics, Iowa State University, Ames, Iowa, United States of America
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6
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Vora M, Pyonteck SM, Popovitchenko T, Matlack TL, Prashar A, Kane NS, Favate J, Shah P, Rongo C. The hypoxia response pathway promotes PEP carboxykinase and gluconeogenesis in C. elegans. Nat Commun 2022; 13:6168. [PMID: 36257965 PMCID: PMC9579151 DOI: 10.1038/s41467-022-33849-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 10/05/2022] [Indexed: 12/31/2022] Open
Abstract
Actively dividing cells, including some cancers, rely on aerobic glycolysis rather than oxidative phosphorylation to generate energy, a phenomenon termed the Warburg effect. Constitutive activation of the Hypoxia Inducible Factor (HIF-1), a transcription factor known for mediating an adaptive response to oxygen deprivation (hypoxia), is a hallmark of the Warburg effect. HIF-1 is thought to promote glycolysis and suppress oxidative phosphorylation. Here, we instead show that HIF-1 can promote gluconeogenesis. Using a multiomics approach, we reveal the genomic, transcriptomic, and metabolomic landscapes regulated by constitutively active HIF-1 in C. elegans. We use RNA-seq and ChIP-seq under aerobic conditions to analyze mutants lacking EGL-9, a key negative regulator of HIF-1. We integrate these approaches to identify over two hundred genes directly and functionally upregulated by HIF-1, including the PEP carboxykinase PCK-1, a rate-limiting mediator of gluconeogenesis. This activation of PCK-1 by HIF-1 promotes survival in response to both oxidative and hypoxic stress. Our work identifies functional direct targets of HIF-1 in vivo, comprehensively describing the metabolome induced by HIF-1 activation in an organism.
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Affiliation(s)
- Mehul Vora
- The Waksman Institute, Rutgers The State University of New Jersey, Piscataway, NJ, 08854, USA
| | - Stephanie M Pyonteck
- The Waksman Institute, Rutgers The State University of New Jersey, Piscataway, NJ, 08854, USA
| | - Tatiana Popovitchenko
- The Waksman Institute, Rutgers The State University of New Jersey, Piscataway, NJ, 08854, USA
| | - Tarmie L Matlack
- The Waksman Institute, Rutgers The State University of New Jersey, Piscataway, NJ, 08854, USA
| | - Aparna Prashar
- The Department of Genetics, Rutgers The State University of New Jersey, Piscataway, NJ, 08854, USA
| | - Nanci S Kane
- The Waksman Institute, Rutgers The State University of New Jersey, Piscataway, NJ, 08854, USA
| | - John Favate
- The Department of Genetics, Rutgers The State University of New Jersey, Piscataway, NJ, 08854, USA
| | - Premal Shah
- The Department of Genetics, Rutgers The State University of New Jersey, Piscataway, NJ, 08854, USA
| | - Christopher Rongo
- The Waksman Institute, Rutgers The State University of New Jersey, Piscataway, NJ, 08854, USA. .,The Department of Genetics, Rutgers The State University of New Jersey, Piscataway, NJ, 08854, USA.
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7
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Cochran JK, Orr SE, Buchwalter DB. Assessing the P crit in relation to temperature and the expression of hypoxia associated genes in the mayfly, Neocloeon triangulifer. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 808:151743. [PMID: 34826479 DOI: 10.1016/j.scitotenv.2021.151743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 11/08/2021] [Accepted: 11/13/2021] [Indexed: 06/13/2023]
Abstract
Hypoxia is a growing concern in aquatic ecosystems. Historically, scientists have used the Pcrit (the dissolved oxygen level below which an animal can no longer oxyregulate) to infer hypoxia tolerance across species. Here, we tested the hypothesis that the Pcrit is positively correlated with temperature in the mayfly, Neocloeon triangulifer. Cross-temperature comparisons showed a modest (r = 0.47), but significant (p < 0.0001) association between temperature and Pcrit despite relatively large interindividual variability (Coefficient of Variance (CV) = 39.9% at 18 °C). We used the expression of hypoxia-responsive genes EGL-9 (an oxygen sensing gene and modulator of HIF-1a activity) and LDH (a hypoxia indicator) to test whether oxygen partial pressure near the Pcrit stimulates expression of hypoxia-responsive genes. Neither gene was upregulated at oxygen levels above the estimated Pcrit, however, at or below the Pcrit estimates, expression of both genes was stimulated (~20- and ~3-fold change for EGL-9 and LDH, respectively). Finally, we evaluated the influence of hypoxic exposure time and pretreatment conditions on the mRNA expression levels of hypoxia-responsive genes. When larvae were exposed to a gradual reduction of DO, hypoxic gene expression was more robust than during instantaneous exposure to hypoxia. Our data provide modest support for traditional interpretation of the Pcrit as a physiologically meaningful shift from aerobic to anaerobic metabolism in N. triangulifer. However, we also discuss limitations of the Pcrit as a proxy measure of hypoxia tolerance at the species level.
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Affiliation(s)
- Jamie K Cochran
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, United States of America
| | - Sarah E Orr
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, United States of America
| | - David B Buchwalter
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, United States of America.
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8
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Doering KRS, Cheng X, Milburn L, Ratnappan R, Ghazi A, Miller DL, Taubert S. Nuclear hormone receptor NHR-49 acts in parallel with HIF-1 to promote hypoxia adaptation in Caenorhabditis elegans. eLife 2022; 11:67911. [PMID: 35285794 PMCID: PMC8959602 DOI: 10.7554/elife.67911] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 03/12/2022] [Indexed: 01/06/2023] Open
Abstract
The response to insufficient oxygen (hypoxia) is orchestrated by the conserved hypoxia-inducible factor (HIF). However, HIF-independent hypoxia response pathways exist that act in parallel with HIF to mediate the physiological hypoxia response. Here, we describe a hypoxia response pathway controlled by Caenorhabditis elegans nuclear hormone receptor NHR-49, an orthologue of mammalian peroxisome proliferator-activated receptor alpha (PPARα). We show that nhr-49 is required for animal survival in hypoxia and is synthetic lethal with hif-1 in this context, demonstrating that these factors act in parallel. RNA-seq analysis shows that in hypoxia nhr-49 regulates a set of genes that are hif-1-independent, including autophagy genes that promote hypoxia survival. We further show that nuclear hormone receptor nhr-67 is a negative regulator and homeodomain-interacting protein kinase hpk-1 is a positive regulator of the NHR-49 pathway. Together, our experiments define a new, essential hypoxia response pathway that acts in parallel with the well-known HIF-mediated hypoxia response.
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Affiliation(s)
- Kelsie RS Doering
- Graduate Program in Medical Genetics, University of British ColumbiaVancouverCanada,British Columbia Children's Hospital Research InstituteVancouverCanada,Centre for Molecular Medicine and Therapeutics, The University of British ColumbiaVancouverCanada
| | - Xuanjin Cheng
- British Columbia Children's Hospital Research InstituteVancouverCanada,Centre for Molecular Medicine and Therapeutics, The University of British ColumbiaVancouverCanada,Department of Medical Genetics, University of British ColumbiaVancouverCanada
| | - Luke Milburn
- Department of Biochemistry, University of Washington School of MedicineSeattleUnited States
| | - Ramesh Ratnappan
- Department of Pediatrics, University of Pittsburgh School of MedicinePittsburghUnited States
| | - Arjumand Ghazi
- Department of Pediatrics, University of Pittsburgh School of MedicinePittsburghUnited States,Departments of Developmental Biology and Cell Biology and Physiology, University of Pittsburgh School of MedicinePittsburghUnited States
| | - Dana L Miller
- Department of Biochemistry, University of Washington School of MedicineSeattleUnited States
| | - Stefan Taubert
- Graduate Program in Medical Genetics, University of British ColumbiaVancouverCanada,British Columbia Children's Hospital Research InstituteVancouverCanada,Centre for Molecular Medicine and Therapeutics, The University of British ColumbiaVancouverCanada,Department of Medical Genetics, University of British ColumbiaVancouverCanada
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9
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Soo SK, Traa A, Rudich PD, Mistry M, Van Raamsdonk JM. Activation of mitochondrial unfolded protein response protects against multiple exogenous stressors. Life Sci Alliance 2021; 4:e202101182. [PMID: 34583931 PMCID: PMC8500221 DOI: 10.26508/lsa.202101182] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 09/10/2021] [Accepted: 09/20/2021] [Indexed: 11/24/2022] Open
Abstract
The mitochondrial unfolded protein response (mitoUPR) is an evolutionarily conserved pathway that responds to mitochondria insults through transcriptional changes, mediated by the transcription factor ATFS-1/ATF-5, which acts to restore mitochondrial homeostasis. In this work, we characterized the role of ATFS-1 in responding to organismal stress. We found that activation of ATFS-1 is sufficient to cause up-regulation of genes involved in multiple stress response pathways including the DAF-16-mediated stress response pathway, the cytosolic unfolded protein response, the endoplasmic reticulum unfolded protein response, the SKN-1-mediated oxidative stress response pathway, the HIF-1-mediated hypoxia response pathway, the p38-mediated innate immune response pathway, and antioxidant genes. Constitutive activation of ATFS-1 increases resistance to multiple acute exogenous stressors, whereas disruption of atfs-1 decreases stress resistance. Although ATFS-1-dependent genes are up-regulated in multiple long-lived mutants, constitutive activation of ATFS-1 decreases lifespan in wild-type animals. Overall, our work demonstrates that ATFS-1 serves a vital role in organismal survival of acute stressors through its ability to activate multiple stress response pathways but that chronic ATFS-1 activation is detrimental for longevity.
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Affiliation(s)
- Sonja K Soo
- Department of Neurology and Neurosurgery, McGill University, Montreal, Canada
- Metabolic Disorders and Complications Program, and Brain Repair and Integrative Neuroscience Program, Research Institute of the McGill University Health Centre, Montreal, Canada
| | - Annika Traa
- Department of Neurology and Neurosurgery, McGill University, Montreal, Canada
- Metabolic Disorders and Complications Program, and Brain Repair and Integrative Neuroscience Program, Research Institute of the McGill University Health Centre, Montreal, Canada
| | - Paige D Rudich
- Department of Neurology and Neurosurgery, McGill University, Montreal, Canada
- Metabolic Disorders and Complications Program, and Brain Repair and Integrative Neuroscience Program, Research Institute of the McGill University Health Centre, Montreal, Canada
| | - Meeta Mistry
- Bioinformatics Core, Harvard School of Public Health, Harvard Medical School, Boston, MA, USA
| | - Jeremy M Van Raamsdonk
- Department of Neurology and Neurosurgery, McGill University, Montreal, Canada
- Metabolic Disorders and Complications Program, and Brain Repair and Integrative Neuroscience Program, Research Institute of the McGill University Health Centre, Montreal, Canada
- Division of Experimental Medicine, Department of Medicine, McGill University, Montreal, Canada
- Department of Genetics, Harvard Medical School, Boston, MA, USA
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10
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Lautens MJ, Tan JH, Serrat X, Del Borrello S, Schertzberg MR, Fraser AG. Identification of enzymes that have helminth-specific active sites and are required for Rhodoquinone-dependent metabolism as targets for new anthelmintics. PLoS Negl Trop Dis 2021; 15:e0009991. [PMID: 34843467 PMCID: PMC8659336 DOI: 10.1371/journal.pntd.0009991] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 12/09/2021] [Accepted: 11/11/2021] [Indexed: 11/18/2022] Open
Abstract
Soil transmitted helminths (STHs) are major human pathogens that infect over a billion people. Resistance to current anthelmintics is rising and new drugs are needed. Here we combine multiple approaches to find druggable targets in the anaerobic metabolic pathways STHs need to survive in their mammalian host. These require rhodoquinone (RQ), an electron carrier used by STHs and not their hosts. We identified 25 genes predicted to act in RQ-dependent metabolism including sensing hypoxia and RQ synthesis and found 9 are required. Since all 9 have mammalian orthologues, we used comparative genomics and structural modeling to identify those with active sites that differ between host and parasite. Together, we found 4 genes that are required for RQ-dependent metabolism and have different active sites. Finding these high confidence targets can open up in silico screens to identify species selective inhibitors of these enzymes as new anthelmintics.
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Affiliation(s)
- Margot J. Lautens
- The Donnelly Centre, University of Toronto, Toronto, Ontario, Canada
| | - June H. Tan
- The Donnelly Centre, University of Toronto, Toronto, Ontario, Canada
| | - Xènia Serrat
- The Donnelly Centre, University of Toronto, Toronto, Ontario, Canada
| | | | | | - Andrew G. Fraser
- The Donnelly Centre, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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11
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Feng D, Zhai Z, Shao Z, Zhang Y, Powell-Coffman JA. Crosstalk in oxygen homeostasis networks: SKN-1/NRF inhibits the HIF-1 hypoxia-inducible factor in Caenorhabditis elegans. PLoS One 2021; 16:e0249103. [PMID: 34242227 PMCID: PMC8270126 DOI: 10.1371/journal.pone.0249103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 06/24/2021] [Indexed: 11/30/2022] Open
Abstract
During development, homeostasis, and disease, organisms must balance responses that allow adaptation to low oxygen (hypoxia) with those that protect cells from oxidative stress. The evolutionarily conserved hypoxia-inducible factors are central to these processes, as they orchestrate transcriptional responses to oxygen deprivation. Here, we employ genetic strategies in C. elegans to identify stress-responsive genes and pathways that modulate the HIF-1 hypoxia-inducible factor and facilitate oxygen homeostasis. Through a genome-wide RNAi screen, we show that RNAi-mediated mitochondrial or proteasomal dysfunction increases the expression of hypoxia-responsive reporter Pnhr-57::GFP in C. elegans. Interestingly, only a subset of these effects requires hif-1. Of particular importance, we found that skn-1 RNAi increases the expression of hypoxia-responsive reporter Pnhr-57::GFP and elevates HIF-1 protein levels. The SKN-1/NRF transcription factor has been shown to promote oxidative stress resistance. We present evidence that the crosstalk between HIF-1 and SKN-1 is mediated by EGL-9, the prolyl hydroxylase that targets HIF-1 for oxygen-dependent degradation. Treatment that induces SKN-1, such as heat or gsk-3 RNAi, increases expression of a Pegl-9::GFP reporter, and this effect requires skn-1 function and a putative SKN-1 binding site in egl-9 regulatory sequences. Collectively, these data support a model in which SKN-1 promotes egl-9 transcription, thereby inhibiting HIF-1. We propose that this interaction enables animals to adapt quickly to changes in cellular oxygenation and to better survive accompanying oxidative stress.
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Affiliation(s)
- Dingxia Feng
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, United States of America
- * E-mail: (JAP-C); (DF)
| | - Zhiwei Zhai
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, United States of America
| | - Zhiyong Shao
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, United States of America
| | - Yi Zhang
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, United States of America
| | - Jo Anne Powell-Coffman
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, United States of America
- * E-mail: (JAP-C); (DF)
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12
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Peng S, Zhang J, Tan X, Huang Y, Xu J, Silk N, Zhang D, Liu Q, Jiang J. The VHL/HIF Axis in the Development and Treatment of Pheochromocytoma/Paraganglioma. Front Endocrinol (Lausanne) 2020; 11:586857. [PMID: 33329393 PMCID: PMC7732471 DOI: 10.3389/fendo.2020.586857] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 10/23/2020] [Indexed: 12/21/2022] Open
Abstract
Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumors originating from chromaffin cells in the adrenal medulla (PCCs) or extra-adrenal sympathetic or parasympathetic paraganglia (PGLs). About 40% of PPGLs result from germline mutations and therefore they are highly inheritable. Although dysfunction of any one of a panel of more than 20 genes can lead to PPGLs, mutations in genes involved in the VHL/HIF axis including PHD, VHL, HIF-2A (EPAS1), and SDHx are more frequently found in PPGLs. Multiple lines of evidence indicate that pseudohypoxia plays a crucial role in the tumorigenesis of PPGLs, and therefore PPGLs are also known as metabolic diseases. However, the interplay between VHL/HIF-mediated pseudohypoxia and metabolic disorder in PPGLs cells is not well-defined. In this review, we will first discuss the VHL/HIF axis and genetic alterations in this axis. Then, we will dissect the underlying mechanisms in VHL/HIF axis-driven PPGL pathogenesis, with special attention paid to the interplay between the VHL/HIF axis and cancer cell metabolism. Finally, we will summarize the currently available compounds/drugs targeting this axis which could be potentially used as PPGLs treatment, as well as their underlying pharmacological mechanisms. The overall goal of this review is to better understand the role of VHL/HIF axis in PPGLs development, to establish more accurate tools in PPGLs diagnosis, and to pave the road toward efficacious therapeutics against metastatic PPGLs.
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Affiliation(s)
- Song Peng
- Department of Urology, Daping Hospital, Army Medical University, Chongqing, China
| | - Jun Zhang
- Department of Urology, Daping Hospital, Army Medical University, Chongqing, China
| | - Xintao Tan
- Department of Urology, Daping Hospital, Army Medical University, Chongqing, China
| | - Yiqiang Huang
- Department of Urology, Daping Hospital, Army Medical University, Chongqing, China
| | - Jing Xu
- Department of Urology, Daping Hospital, Army Medical University, Chongqing, China
| | - Natalie Silk
- Department of Bio-Medical Sciences, Philadelphia College of Osteopathic Medicine, Philadelphia, PA, United States
| | - Dianzheng Zhang
- Department of Bio-Medical Sciences, Philadelphia College of Osteopathic Medicine, Philadelphia, PA, United States
| | - Qiuli Liu
- Department of Urology, Daping Hospital, Army Medical University, Chongqing, China
- *Correspondence: Jun Jiang, ; Qiuli Liu,
| | - Jun Jiang
- Department of Urology, Daping Hospital, Army Medical University, Chongqing, China
- *Correspondence: Jun Jiang, ; Qiuli Liu,
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13
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Modeling succinate dehydrogenase loss disorders in C. elegans through effects on hypoxia-inducible factor. PLoS One 2019; 14:e0227033. [PMID: 31887185 PMCID: PMC6936837 DOI: 10.1371/journal.pone.0227033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 12/10/2019] [Indexed: 12/03/2022] Open
Abstract
Mitochondrial disorders arise from defects in nuclear genes encoding enzymes of oxidative metabolism. Mutations of metabolic enzymes in somatic tissues can cause cancers due to oncometabolite accumulation. Paraganglioma and pheochromocytoma are examples, whose etiology and therapy are complicated by the absence of representative cell lines or animal models. These tumors can be driven by loss of the tricarboxylic acid cycle enzyme succinate dehydrogenase. We exploit the relationship between succinate accumulation, hypoxic signaling, egg-laying behavior, and morphology in C. elegans to create genetic and pharmacological models of succinate dehydrogenase loss disorders. With optimization, these models may enable future high-throughput screening efforts.
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14
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Choi H, Cho SC, Ha YW, Ocampo B, Park S, Chen S, Bennett CF, Han J, Rossner R, Kang JS, Lee YL, Park SC, Kaeberlein M. DDS promotes longevity through a microbiome-mediated starvation signal. TRANSLATIONAL MEDICINE OF AGING 2019; 3:64-69. [PMID: 32190786 PMCID: PMC7080190 DOI: 10.1016/j.tma.2019.07.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The antibiotic diaminodiphenyl sulfone (DDS) is used in combination with other antibiotics as a first line treatment for leprosy. DDS has been previously reported to extend lifespan in Caenorhabditis elegans through inhibition of pyruvate kinase and decreased mitochondrial function. Here we report an alternative mechanism of action by which DDS promotes longevity in C. elegans by reducing folate production by the microbiome. This results in altered methionine cycle metabolite levels mimicking the effects of metformin and lifespan extension that is dependent on the starvation- and hypoxia-induced flavin containing monoxygenase, FMO-2.
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Affiliation(s)
- Haeri Choi
- Department of Obstetrics & Gynecology, Oregon Health and Science University, Portland, OR 97239 USA
- Center for Developmental Health, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR 97239 USA
| | - Sung Chun Cho
- Well Aging Research Center, Daegu Geongbuk Institute Science and Technology (DGIST), Daegu, 42988, South Korea
| | - Young Wan Ha
- Well Aging Research Center, Samsung Advanced Institute of Technology (SAIT), Suwon, South Korea
| | - Billie Ocampo
- Department of Pathology, University of Washington, Seattle, Washington, USA
| | - Shirley Park
- Department of Pathology, University of Washington, Seattle, Washington, USA
| | - Shiwen Chen
- Department of Pathology, University of Washington, Seattle, Washington, USA
| | | | - Jeehae Han
- Department of Pathology, University of Washington, Seattle, Washington, USA
| | - Ryan Rossner
- Department of Pathology, University of Washington, Seattle, Washington, USA
| | - Jong-Sun Kang
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon 16419, South Korea
- Samsung Biomedical Institute, Samsung Medical Center, Seoul 06351, South Korea
| | - Yun-ll Lee
- Well Aging Research Center, Daegu Geongbuk Institute Science and Technology (DGIST), Daegu, 42988, South Korea
| | - Sang Chul Park
- Well Aging Research Center, Daegu Geongbuk Institute Science and Technology (DGIST), Daegu, 42988, South Korea
- The Future Life and Society Research Center, Chonnam National University, Gwangju, South Korea
| | - Matt Kaeberlein
- Department of Pathology, University of Washington, Seattle, Washington, USA
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15
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Maxeiner S, Grolleman J, Schmid T, Kammenga J, Hajnal A. The hypoxia-response pathway modulates RAS/MAPK-mediated cell fate decisions in Caenorhabditis elegans. Life Sci Alliance 2019; 2:2/3/e201800255. [PMID: 31126994 PMCID: PMC6536719 DOI: 10.26508/lsa.201800255] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 05/16/2019] [Accepted: 05/17/2019] [Indexed: 01/01/2023] Open
Abstract
Animals need to adjust many cellular functions to oxygen availability to adapt to changing environmental conditions. We have used the nematode Caenorhabditis elegans as a model to investigate how variations in oxygen concentrations affect cell fate specification during development. Here, we show that several processes controlled by the conserved RTK/RAS/MAPK pathway are sensitive to changes in the atmospheric oxygen concentration. In the vulval precursor cells (VPCs), the hypoxia-inducible factor HIF-1 activates the expression of the nuclear hormone receptor NHR-57 to counteract RAS/MAPK-induced differentiation. Furthermore, cross-talk between the NOTCH and hypoxia-response pathways modulates the capability of the VPCs to respond to RAS/MAPK signaling. Lateral NOTCH signaling positively regulates the prolyl hydroxylase EGL-9, which promotes HIF-1 degradation in uncommitted VPCs and permits RAS/MAPK-induced differentiation. By inducing DELTA family NOTCH ligands, RAS/MAPK signaling creates a positive feedback loop that represses HIF-1 and NHR-57 expression in the proximal VPCs and keeps them capable of differentiating. This regulatory network formed by the NOTCH, hypoxia, and RAS/MAPK pathways may allow the animals to adapt developmental processes to variations in oxygen concentration.
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Affiliation(s)
- Sabrina Maxeiner
- Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland.,PhD Program in Molecular Life Sciences, University and ETH Zurich, Zurich, Switzerland
| | - Judith Grolleman
- Laboratory of Nematology, Wageningen University, Wageningen, The Netherlands
| | - Tobias Schmid
- Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Jan Kammenga
- Laboratory of Nematology, Wageningen University, Wageningen, The Netherlands
| | - Alex Hajnal
- Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
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16
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Pender CL, Horvitz HR. Hypoxia-inducible factor cell non-autonomously regulates C. elegans stress responses and behavior via a nuclear receptor. eLife 2018; 7:36828. [PMID: 30010540 PMCID: PMC6078495 DOI: 10.7554/elife.36828] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 07/15/2018] [Indexed: 12/16/2022] Open
Abstract
The HIF (hypoxia-inducible factor) transcription factor is the master regulator of the metazoan response to chronic hypoxia. In addition to promoting adaptations to low oxygen, HIF drives cytoprotective mechanisms in response to stresses and modulates neural circuit function. How most HIF targets act in the control of the diverse aspects of HIF-regulated biology remains unknown. We discovered that a HIF target, the C. elegans gene cyp-36A1, is required for numerous HIF-dependent processes, including modulation of gene expression, stress resistance, and behavior. cyp-36A1 encodes a cytochrome P450 enzyme that we show controls expression of more than a third of HIF-induced genes. CYP-36A1 acts cell non-autonomously by regulating the activity of the nuclear hormone receptor NHR-46, suggesting that CYP-36A1 functions as a biosynthetic enzyme for a hormone ligand of this receptor. We propose that regulation of HIF effectors through activation of cytochrome P450 enzyme/nuclear receptor signaling pathways could similarly occur in humans.
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Affiliation(s)
- Corinne L Pender
- Department of Biology, Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, United States.,McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, United States.,Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, United States
| | - H Robert Horvitz
- Department of Biology, Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, United States.,McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, United States.,Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, United States
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17
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Kim KS, Chou H, Funk DH, Jackson JK, Sweeney BW, Buchwalter DB. Physiological responses to short-term thermal stress in mayfly (Neocloeon triangulifer) larvae in relation to upper thermal limits. J Exp Biol 2017; 220:2598-2605. [DOI: 10.1242/jeb.156919] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2017] [Accepted: 05/04/2017] [Indexed: 01/09/2023]
Abstract
ABSTRACT
Understanding species' thermal limits and their physiological determinants is critical in light of climate change and other human activities that warm freshwater ecosystems. Here, we ask whether oxygen limitation determines the chronic upper thermal limits in larvae of the mayfly Neocloeon triangulifer, an emerging model for ecological and physiological studies. Our experiments are based on a robust understanding of the upper acute (∼40°C) and chronic thermal limits of this species (>28°C, ≤30°C) derived from full life cycle rearing experiments across temperatures. We tested two related predictions derived from the hypothesis that oxygen limitation sets the chronic upper thermal limits: (1) aerobic scope declines in mayfly larvae as they approach and exceed temperatures that are chronically lethal to larvae; and (2) genes indicative of hypoxia challenge are also responsive in larvae exposed to ecologically relevant thermal limits. Neither prediction held true. We estimated aerobic scope by subtracting measurements of standard oxygen consumption rates from measurements of maximum oxygen consumption rates, the latter of which was obtained by treating with the metabolic uncoupling agent carbonyl cyanide-4-(trifluoromethoxy) pheylhydrazone (FCCP). Aerobic scope was similar in larvae held below and above chronic thermal limits. Genes indicative of oxygen limitation (LDH, EGL-9) were only upregulated under hypoxia or during exposure to temperatures beyond the chronic (and more ecologically relevant) thermal limits of this species (LDH). Our results suggest that the chronic thermal limits of this species are likely not driven by oxygen limitation, but rather are determined by other factors, e.g. bioenergetics costs. We caution against the use of short-term thermal ramping approaches to estimate critical thermal limits (CTmax) in aquatic insects because those temperatures are typically higher than those that occur in nature.
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Affiliation(s)
- Kyoung Sun Kim
- Graduate Toxicology Program, Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, USA
| | - Hsuan Chou
- Graduate Toxicology Program, Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, USA
| | - David H. Funk
- Stroud Water Research Center, Avondale, PA 19311, USA
| | | | | | - David B. Buchwalter
- Graduate Toxicology Program, Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, USA
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18
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Rossner R, Kaeberlein M, Leiser SF. Flavin-containing monooxygenases in aging and disease: Emerging roles for ancient enzymes. J Biol Chem 2017; 292:11138-11146. [PMID: 28515321 DOI: 10.1074/jbc.r117.779678] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Flavin-containing monooxygenases (FMOs) are primarily studied as xenobiotic metabolizing enzymes with a prominent role in drug metabolism. In contrast, endogenous functions and substrates of FMOs are less well understood. A growing body of recent evidence, however, implicates FMOs in aging, several diseases, and metabolic pathways. The evidence suggests an important role for these well-conserved proteins in multiple processes and raises questions about the endogenous substrate(s) and regulation of FMOs. Here, we present an overview of evidence for FMOs' involvement in aging and disease, discussing the biological context and arguing for increased investigation into the function of these enzymes.
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Affiliation(s)
- Ryan Rossner
- From the Department of Pathology, University of Washington, Seattle, Washington 98195 and
| | - Matt Kaeberlein
- From the Department of Pathology, University of Washington, Seattle, Washington 98195 and
| | - Scott F Leiser
- the Departments of Molecular & Integrative Physiology and .,Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109
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19
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Ganner A, Neumann-Haefelin E. Genetic kidney diseases: Caenorhabditis elegans as model system. Cell Tissue Res 2017; 369:105-118. [PMID: 28484847 DOI: 10.1007/s00441-017-2622-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 03/31/2017] [Indexed: 12/18/2022]
Abstract
Despite its apparent simplicity, the nematode Caenorhabditis elegans has a high rating as a model in molecular and developmental biology and biomedical research. C. elegans has no excretory system comparable with the mammalian kidney but many of the genes and molecular pathways involved in human kidney diseases are conserved in C. elegans. The plethora of genetic, molecular and imaging tools available in C. elegans has enabled major discoveries in renal research and advanced our understanding of the pathogenesis of genetic kidney diseases. In particular, studies in C. elegans have pioneered the fundamental role of cilia for cystic kidney diseases. In addition, proteins of the glomerular filtration barrier and podocytes are critical for cell recognition, assembly of functional neuronal circuits, mechanosensation and signal transduction in C. elegans. C. elegans has also proved tremendously valuable for aging research and the Von Hippel-Lindau tumor suppressor gene has been shown to modulate lifespan in the nematode. Further, studies of the excretory canal, membrane transport and ion channel function in C. elegans have provided insights into mechanisms of tubulogenesis and cellular homeostasis. This review recounts the way that C. elegans can be used to investigate various aspects of genetic and molecular nephrology. This model system opens up an exciting and new area of study of renal development and diseases.
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Affiliation(s)
- Athina Ganner
- Department of Nephrology, Medical Center, University of Freiburg, Hugstetter Strasse 55, 79106 Freiburg, Germany
| | - Elke Neumann-Haefelin
- Department of Nephrology, Medical Center, University of Freiburg, Hugstetter Strasse 55, 79106 Freiburg, Germany.
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20
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Risk of Hypertension With Sorafenib Use in Patients With Cancer: A Meta-Analysis From 20,494 Patients. Am J Ther 2017; 24:e81-e101. [DOI: 10.1097/mjt.0000000000000331] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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21
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Chen T, Zhou Q, Tang H, Bozkanat M, Yuan JXJ, Raj JU, Zhou G. miR-17/20 Controls Prolyl Hydroxylase 2 (PHD2)/Hypoxia-Inducible Factor 1 (HIF1) to Regulate Pulmonary Artery Smooth Muscle Cell Proliferation. J Am Heart Assoc 2016; 5:JAHA.116.004510. [PMID: 27919930 PMCID: PMC5210422 DOI: 10.1161/jaha.116.004510] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Background Previously we found that smooth muscle cell (SMC)‐specific knockout of miR‐17~92 attenuates hypoxia‐induced pulmonary hypertension. However, the mechanism underlying miR‐17~92‐mediated pulmonary artery SMC (PASMC) proliferation remains unclear. We sought to investigate whether miR‐17~92 regulates hypoxia‐inducible factor (HIF) activity and PASMC proliferation via prolyl hydroxylases (PHDs). Methods and Results We show that hypoxic sm‐17~92−/− mice have decreased hematocrit, red blood cell counts, and hemoglobin contents. The sm‐17~92−/− mouse lungs express decreased mRNA levels of HIF targets and increased levels of PHD2. miR‐17~92 inhibitors suppress hypoxia‐induced levels of HIF1α, VEGF, Glut1, HK2, and PDK1 but not HIF2α in vitro in PASMC. Overexpression of miR‐17 in PASMC represses PHD2 expression, whereas miR‐17/20a inhibitors induce PHD2 expression. The 3′‐UTR of PHD2 contains a functional miR‐17/20a seed sequence. Silencing of PHD2 induces HIF1α and PCNA protein levels, whereas overexpression of PHD2 decreases HIF1α and cell proliferation. SMC‐specific knockout of PHD2 enhances hypoxia‐induced vascular remodeling and exacerbates established pulmonary hypertension in mice. PHD2 activator R59949 reverses vessel remodeling in existing hypertensive mice. PHDs are dysregulated in PASMC isolated from pulmonary arterial hypertension patients. Conclusions Our results suggest that PHD2 is a direct target of miR‐17/20a and that miR‐17~92 contributes to PASMC proliferation and polycythemia by suppression of PHD2 and induction of HIF1α.
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Affiliation(s)
- Tianji Chen
- Department of Pediatrics, University of Illinois at Chicago, Chicago, IL
| | - Qiyuan Zhou
- Department of Pediatrics, University of Illinois at Chicago, Chicago, IL
| | - Haiyang Tang
- Department of Medicine, University of Arizona, Tucson, AZ
| | - Melike Bozkanat
- Department of Pediatrics, University of Illinois at Chicago, Chicago, IL
| | - Jason X-J Yuan
- Department of Medicine, University of Arizona, Tucson, AZ
| | - J Usha Raj
- Department of Pediatrics, University of Illinois at Chicago, Chicago, IL.,Children's Hospital University of Illinois, University of Illinois Hospital and Health Sciences System, Chicago, IL
| | - Guofei Zhou
- Department of Pediatrics, University of Illinois at Chicago, Chicago, IL
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22
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Wang Y, Zhao W, Gao Q, Fan L, Qin Y, Zhou H, Li M, Fang J. pVHL mediates K63-linked ubiquitination of IKKβ, leading to IKKβ inactivation. Cancer Lett 2016; 383:1-8. [PMID: 27693634 DOI: 10.1016/j.canlet.2016.09.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 09/09/2016] [Accepted: 09/10/2016] [Indexed: 01/06/2023]
Abstract
Nuclear factor (NF)-κB is a transcription factor that plays an important role in many biological functions. Regulation of NF-κB activity is complicated, and ubiquitination is essential for NF-κB activation. Hypoxia can activate NF-κB. However, the underlying mechanism remains unclear. pVHL is a tumour suppressor and functions as an adaptor of E3-ligase. In this study, we demonstrated that pVHL inhibits NF-κB by mediating K63-ubiquitination of IKKβ, which is dependent on oxygen. We found that pVHL mediates K63-linked ubiquitination of IKKβ, which is an upstream regulator of NF-κB. The pVHL-mediated K63-ubiquitination of IKKβ prevents TAK1 binding, which leads to the inhibition of IKKβ phosphorylation and NF-κB activation. pVHL-mediated K63-ubiquitination of IKKβ is inhibited under hypoxia. DMOG, which is a specific inhibitor of prolyl hydroxylases, also suppresses K63-ubiquitination of IKKβ. Prolyl hydroxylase (PHD) 1 enhances K63-ubiquitination of IKKβ and inhibits IKKβ phosphorylation. These results suggest a novel function for pVHL in mediating K63-linked ubiquitination of IKKβ, which plays a role in the regulation of IKK/NF-κB signalling. The results also provide new insight into the mechanism of NF-κB activation through hypoxia.
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Affiliation(s)
- Yuxin Wang
- Key Laboratory of Food Safety Research, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China; University of Chinese Academy of Sciences, China
| | - Wenting Zhao
- Key Laboratory of Food Safety Research, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China; University of Chinese Academy of Sciences, China
| | - Qiang Gao
- Key Laboratory of Food Safety Research, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China; University of Chinese Academy of Sciences, China
| | - Li Fan
- Key Laboratory of Food Safety Research, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China; University of Chinese Academy of Sciences, China
| | - Yanqing Qin
- Key Laboratory of Food Safety Research, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China; University of Chinese Academy of Sciences, China
| | - Hu Zhou
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 200031, China
| | - Min Li
- Department of Surgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Jing Fang
- Key Laboratory of Food Safety Research, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China; University of Chinese Academy of Sciences, China; Key Laboratory of Food Safety Risk Assessment, Ministry of Health, Beijing, China.
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23
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Kamal M, D'Amora DR, Kubiseski TJ. Loss of hif-1 promotes resistance to the exogenous mitochondrial stressor ethidium bromide in Caenorhabditis elegans. BMC Cell Biol 2016; 17 Suppl 1:34. [PMID: 27618966 PMCID: PMC5020483 DOI: 10.1186/s12860-016-0112-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 09/06/2016] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Mitochondrial dysfunction is one of the leading causes of neurological disorders in humans. Mitochondrial perturbations lead to adaptive mechanisms that include HIF-1 stabilization, though the consequences of increased levels of HIF-1 following mitochondrial stress remain poorly understood. RESULTS Using Caenorhabditis elegans, we show that a hif-1 loss-of-function mutation confers resistance towards the mitochondrial toxin ethidium bromide (EtBr) and suppresses EtBr-induced production of ROS. In mammals, the PD-related gene DJ-1 is known to act as a redox sensor to confer protection against antioxidants and mitochondrial inhibitors. A deletion mutant of the C. elegans homolog djr-1.1 also showed increased resistance to EtBr. Furthermore, our data implicates p38 MAP kinase as an indispensable factor for survival against mitochondrial stress in both hif-1 and djr-1.1 mutants. CONCLUSIONS We propose that EtBr-induced HIF-1 activates pathways that are antagonistic in conferring protection against EtBr toxicity and that blocking HIF-1 activity may promote survival in cells with compromised mitochondrial function.
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Affiliation(s)
- Muntasir Kamal
- Department of Biology, York University, Toronto, Canada.,Present address: Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | | | - Terrance J Kubiseski
- Department of Biology, York University, Toronto, Canada. .,Department of Neuroscience, York University, Toronto, Canada.
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24
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GATA transcription factor as a likely key regulator of the Caenorhabditis elegans innate immune response against gut pathogens. ZOOLOGY 2016; 119:244-53. [DOI: 10.1016/j.zool.2016.05.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 04/19/2016] [Accepted: 05/27/2016] [Indexed: 01/29/2023]
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25
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Leiser SF, Rossner R, Kaeberlein M. New insights into cell non-autonomous mechanisms of the C. elegans hypoxic response. WORM 2016; 5:e1176823. [PMID: 27383456 DOI: 10.1080/21624054.2016.1176823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 04/05/2016] [Indexed: 10/21/2022]
Abstract
The hypoxic response is a well-studied and highly conserved biological response to low oxygen availability. First described more than 20 y ago, the traditional model for this response is that declining oxygen levels lead to stabilization of hypoxia-inducible transcription factors (HIFs), which then bind to hypoxia responsive elements (HREs) in target genes to mediate the transcriptional changes collectively known as the hypoxic response.(1,2) Recent work in C. elegans has forced a re-evaluation of this model by indicating that the worm HIF (HIF-1) can mediate effects in a cell non-autonomous fashion and, in at least one case, increase expression of an intestinal hypoxic response target gene in cells lacking HIF-1.
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Affiliation(s)
- Scott F Leiser
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA; Division of Geriatric and Palliative Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Ryan Rossner
- Department of Pathology, University of Washington , Seattle, WA, USA
| | - Matt Kaeberlein
- Department of Pathology, University of Washington , Seattle, WA, USA
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26
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Zhou Q, Chen T, Zhang W, Bozkanat M, Li Y, Xiao L, van Breemen RB, Christman JW, Sznajder JI, Zhou G. Suppression of von Hippel-Lindau Protein in Fibroblasts Protects against Bleomycin-Induced Pulmonary Fibrosis. Am J Respir Cell Mol Biol 2016; 54:728-39. [PMID: 26488390 PMCID: PMC4942192 DOI: 10.1165/rcmb.2015-0111oc] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 10/16/2015] [Indexed: 12/20/2022] Open
Abstract
We have reported that von Hippel-Lindau protein (pVHL) expression is elevated in human and mouse fibrotic lungs and that overexpression of pVHL stimulates fibroblast proliferation. We sought to determine whether loss of pVHL in fibroblasts prevents injury and fibrosis in mice that are treated with bleomycin. We generated heterozygous fibroblast-specific pVHL (Fsp-VHL) knockdown mice (Fsp-VHL(+/-)) and homozygous Fsp-VHL knockout mice (Fsp-VHL(-/-)) by crossbreeding vhlh 2-lox mice (VHL(fl/fl)) with Fsp-Cre recombinase mice. Our data show that Fsp-VHL(-/-) mice, but not Fsp-VHL(+/-) mice, have elevated red blood cell counts, hematocrit, hemoglobin content, and expression of hypoxia-inducible factor (HIF) targets, indicating HIF activation. To examine the role of pVHL in bleomycin-induced lung injury and fibrosis in vivo, we administered PBS or bleomycin to age-, sex-, and strain-matched 8-week-old VHL(fl/fl), Fsp-VHL(+/-), and Fsp-VHL(-/-) mice. In Fsp-VHL(+/-) and Fsp-VHL(-/-) mice, bleomycin-induced collagen accumulation, fibroblast proliferation, differentiation, and matrix protein dysregulation were markedly attenuated. Suppression of pVHL also decreased bleomycin-induced Wnt signaling and prostaglandin E2 signaling but did not affect bleomycin-induced initial acute lung injury and lung inflammation. These results indicate that pVHL has a pivotal role in bleomycin-induced pulmonary fibrosis, possibly via an HIF-independent pathway. Paradoxically, pVHL does not affect bleomycin-induced lung injury and inflammation, indicating a separation of the mechanisms involved in injury/inflammation from those involved in pulmonary fibrosis.
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Affiliation(s)
| | | | - Wei Zhang
- Department of Preventive Medicine and
| | | | | | - Lei Xiao
- Department of Medicine, Division of Pulmonary, Critical Care, Sleep, and Allergy, and
| | | | - John W. Christman
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Ohio State University, Columbus, Ohio
| | - Jacob I. Sznajder
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois; and
| | - Guofei Zhou
- Departments of Pediatrics and
- Cancer Center, University of Illinois at Chicago, Chicago, Illinois
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27
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Nielsen SM, Rhodes L, Blanco I, Chung WK, Eng C, Maher ER, Richard S, Giles RH. Von Hippel-Lindau Disease: Genetics and Role of Genetic Counseling in a Multiple Neoplasia Syndrome. J Clin Oncol 2016; 34:2172-81. [PMID: 27114602 DOI: 10.1200/jco.2015.65.6140] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Von Hippel-Lindau disease (VHL) is one of the most common inherited neoplasia syndromes and is characterized by highly vascular tumors of the eyes, brain, and spine, as well as benign and malignant tumors and/or cysts of the kidneys, adrenal medullae and sympathetic paraganglia, endolymphatic sac, epididymis, and broad ligament. Since the discovery of the VHL gene in 1993, more than 900 families with VHL have been identified and examined. Genetic testing for VHL is widely available and will detect a disease-causing mutation in rate 95% to 100% of individuals who have a clinical diagnosis of VHL, making it the standard of care for diagnosis of VHL. Furthermore, genetic testing for VHL is indicated in some individuals with seemingly sporadic VHL-related tumor types, as ≤ 10% of pheochromocytoma or early-onset renal cell carcinoma and ≤ 40% of CNS hemangioblastoma harbor germline VHL mutations without a family history or additional features of VHL disease. The majority of VHL mutations are private, but there are also well-characterized founder mutations. VHL is a complex, multiorgan disease that spans the breadth of oncology subspecialties, and, as such, providers in these subspecialties should be aware of when to consider a diagnosis of VHL, when to refer a patient to a genetics specialist for consideration of gene testing, and, perhaps most importantly, how to communicate this sensitive information in an age-appropriate manner to at-risk families. This review will provide state-of-the-art information regarding the genetics of VHL and will serve as a key reference for nongenetics professionals who encounter patients with VHL.
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Affiliation(s)
- Sarah M Nielsen
- Sarah M. Nielsen and Lindsay Rhodes, The University of Chicago, Chicago, IL; Ignacio Blanco, Hospital Universitari Germans Trias i Pujol, UAB - Universitat Autònoma de Barcelona, Barcelona, Spain; Wendy K. Chung, Columbia University, New York, NY; Charis Eng, Cleveland Clinic; Charis Eng, Case Western Reserve University School of Medicine, Cleveland, OH; Eamonn R. Maher, University of Cambridge and Cambridge NIHR Biomedical Research Centre, Cambridge, United Kingdom; Stéphane Richard, Réseau National pour Cancers Rares de l'Adulte PREDIR, INCa/AP-HP, Hôpital Bicêtre, Le Kremlin Bicêtre; Stéphane Richard, INSERM U1186, Gustave Roussy Cancer Campus, Villejuif, France; Rachel H. Giles, University Medical Center Utrecht, Regenerative Medicine Center Utrecht, Utrecht; and Rachel H. Giles, Dutch VHL Patient Organization, Gouda, the Netherlands.
| | - Lindsay Rhodes
- Sarah M. Nielsen and Lindsay Rhodes, The University of Chicago, Chicago, IL; Ignacio Blanco, Hospital Universitari Germans Trias i Pujol, UAB - Universitat Autònoma de Barcelona, Barcelona, Spain; Wendy K. Chung, Columbia University, New York, NY; Charis Eng, Cleveland Clinic; Charis Eng, Case Western Reserve University School of Medicine, Cleveland, OH; Eamonn R. Maher, University of Cambridge and Cambridge NIHR Biomedical Research Centre, Cambridge, United Kingdom; Stéphane Richard, Réseau National pour Cancers Rares de l'Adulte PREDIR, INCa/AP-HP, Hôpital Bicêtre, Le Kremlin Bicêtre; Stéphane Richard, INSERM U1186, Gustave Roussy Cancer Campus, Villejuif, France; Rachel H. Giles, University Medical Center Utrecht, Regenerative Medicine Center Utrecht, Utrecht; and Rachel H. Giles, Dutch VHL Patient Organization, Gouda, the Netherlands
| | - Ignacio Blanco
- Sarah M. Nielsen and Lindsay Rhodes, The University of Chicago, Chicago, IL; Ignacio Blanco, Hospital Universitari Germans Trias i Pujol, UAB - Universitat Autònoma de Barcelona, Barcelona, Spain; Wendy K. Chung, Columbia University, New York, NY; Charis Eng, Cleveland Clinic; Charis Eng, Case Western Reserve University School of Medicine, Cleveland, OH; Eamonn R. Maher, University of Cambridge and Cambridge NIHR Biomedical Research Centre, Cambridge, United Kingdom; Stéphane Richard, Réseau National pour Cancers Rares de l'Adulte PREDIR, INCa/AP-HP, Hôpital Bicêtre, Le Kremlin Bicêtre; Stéphane Richard, INSERM U1186, Gustave Roussy Cancer Campus, Villejuif, France; Rachel H. Giles, University Medical Center Utrecht, Regenerative Medicine Center Utrecht, Utrecht; and Rachel H. Giles, Dutch VHL Patient Organization, Gouda, the Netherlands
| | - Wendy K Chung
- Sarah M. Nielsen and Lindsay Rhodes, The University of Chicago, Chicago, IL; Ignacio Blanco, Hospital Universitari Germans Trias i Pujol, UAB - Universitat Autònoma de Barcelona, Barcelona, Spain; Wendy K. Chung, Columbia University, New York, NY; Charis Eng, Cleveland Clinic; Charis Eng, Case Western Reserve University School of Medicine, Cleveland, OH; Eamonn R. Maher, University of Cambridge and Cambridge NIHR Biomedical Research Centre, Cambridge, United Kingdom; Stéphane Richard, Réseau National pour Cancers Rares de l'Adulte PREDIR, INCa/AP-HP, Hôpital Bicêtre, Le Kremlin Bicêtre; Stéphane Richard, INSERM U1186, Gustave Roussy Cancer Campus, Villejuif, France; Rachel H. Giles, University Medical Center Utrecht, Regenerative Medicine Center Utrecht, Utrecht; and Rachel H. Giles, Dutch VHL Patient Organization, Gouda, the Netherlands
| | - Charis Eng
- Sarah M. Nielsen and Lindsay Rhodes, The University of Chicago, Chicago, IL; Ignacio Blanco, Hospital Universitari Germans Trias i Pujol, UAB - Universitat Autònoma de Barcelona, Barcelona, Spain; Wendy K. Chung, Columbia University, New York, NY; Charis Eng, Cleveland Clinic; Charis Eng, Case Western Reserve University School of Medicine, Cleveland, OH; Eamonn R. Maher, University of Cambridge and Cambridge NIHR Biomedical Research Centre, Cambridge, United Kingdom; Stéphane Richard, Réseau National pour Cancers Rares de l'Adulte PREDIR, INCa/AP-HP, Hôpital Bicêtre, Le Kremlin Bicêtre; Stéphane Richard, INSERM U1186, Gustave Roussy Cancer Campus, Villejuif, France; Rachel H. Giles, University Medical Center Utrecht, Regenerative Medicine Center Utrecht, Utrecht; and Rachel H. Giles, Dutch VHL Patient Organization, Gouda, the Netherlands
| | - Eamonn R Maher
- Sarah M. Nielsen and Lindsay Rhodes, The University of Chicago, Chicago, IL; Ignacio Blanco, Hospital Universitari Germans Trias i Pujol, UAB - Universitat Autònoma de Barcelona, Barcelona, Spain; Wendy K. Chung, Columbia University, New York, NY; Charis Eng, Cleveland Clinic; Charis Eng, Case Western Reserve University School of Medicine, Cleveland, OH; Eamonn R. Maher, University of Cambridge and Cambridge NIHR Biomedical Research Centre, Cambridge, United Kingdom; Stéphane Richard, Réseau National pour Cancers Rares de l'Adulte PREDIR, INCa/AP-HP, Hôpital Bicêtre, Le Kremlin Bicêtre; Stéphane Richard, INSERM U1186, Gustave Roussy Cancer Campus, Villejuif, France; Rachel H. Giles, University Medical Center Utrecht, Regenerative Medicine Center Utrecht, Utrecht; and Rachel H. Giles, Dutch VHL Patient Organization, Gouda, the Netherlands
| | - Stéphane Richard
- Sarah M. Nielsen and Lindsay Rhodes, The University of Chicago, Chicago, IL; Ignacio Blanco, Hospital Universitari Germans Trias i Pujol, UAB - Universitat Autònoma de Barcelona, Barcelona, Spain; Wendy K. Chung, Columbia University, New York, NY; Charis Eng, Cleveland Clinic; Charis Eng, Case Western Reserve University School of Medicine, Cleveland, OH; Eamonn R. Maher, University of Cambridge and Cambridge NIHR Biomedical Research Centre, Cambridge, United Kingdom; Stéphane Richard, Réseau National pour Cancers Rares de l'Adulte PREDIR, INCa/AP-HP, Hôpital Bicêtre, Le Kremlin Bicêtre; Stéphane Richard, INSERM U1186, Gustave Roussy Cancer Campus, Villejuif, France; Rachel H. Giles, University Medical Center Utrecht, Regenerative Medicine Center Utrecht, Utrecht; and Rachel H. Giles, Dutch VHL Patient Organization, Gouda, the Netherlands
| | - Rachel H Giles
- Sarah M. Nielsen and Lindsay Rhodes, The University of Chicago, Chicago, IL; Ignacio Blanco, Hospital Universitari Germans Trias i Pujol, UAB - Universitat Autònoma de Barcelona, Barcelona, Spain; Wendy K. Chung, Columbia University, New York, NY; Charis Eng, Cleveland Clinic; Charis Eng, Case Western Reserve University School of Medicine, Cleveland, OH; Eamonn R. Maher, University of Cambridge and Cambridge NIHR Biomedical Research Centre, Cambridge, United Kingdom; Stéphane Richard, Réseau National pour Cancers Rares de l'Adulte PREDIR, INCa/AP-HP, Hôpital Bicêtre, Le Kremlin Bicêtre; Stéphane Richard, INSERM U1186, Gustave Roussy Cancer Campus, Villejuif, France; Rachel H. Giles, University Medical Center Utrecht, Regenerative Medicine Center Utrecht, Utrecht; and Rachel H. Giles, Dutch VHL Patient Organization, Gouda, the Netherlands
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Alam T, Maruyama H, Li C, Pastuhov SI, Nix P, Bastiani M, Hisamoto N, Matsumoto K. Axotomy-induced HIF-serotonin signalling axis promotes axon regeneration in C. elegans. Nat Commun 2016; 7:10388. [PMID: 26790951 PMCID: PMC4735912 DOI: 10.1038/ncomms10388] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 12/05/2015] [Indexed: 12/28/2022] Open
Abstract
The molecular mechanisms underlying the ability of axons to regenerate after injury remain poorly understood. Here we show that in Caenorhabditis elegans, axotomy induces ectopic expression of serotonin (5-HT) in axotomized non-serotonergic neurons via HIF-1, a hypoxia-inducible transcription factor, and that 5-HT subsequently promotes axon regeneration by autocrine signalling through the SER-7 5-HT receptor. Furthermore, we identify the rhgf-1 and rga-5 genes, encoding homologues of RhoGEF and RhoGAP, respectively, as regulators of axon regeneration. We demonstrate that one pathway initiated by SER-7 acts upstream of the C. elegans RhoA homolog RHO-1 in neuron regeneration, which functions via G12α and RHGF-1. In this pathway, RHO-1 inhibits diacylglycerol kinase, resulting in an increase in diacylglycerol. SER-7 also promotes axon regeneration by activating the cyclic AMP (cAMP) signalling pathway. Thus, HIF-1-mediated activation of 5-HT signalling promotes axon regeneration by activating both the RhoA and cAMP pathways.
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Affiliation(s)
- Tanimul Alam
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
| | - Hiroki Maruyama
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
| | - Chun Li
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
| | - Strahil Iv. Pastuhov
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
| | - Paola Nix
- Department of Biology, University of Utah, 257 South 1400 East, Salt Lake City, Utah 84112-0840, USA
| | - Michael Bastiani
- Department of Biology, University of Utah, 257 South 1400 East, Salt Lake City, Utah 84112-0840, USA
| | - Naoki Hisamoto
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
| | - Kunihiro Matsumoto
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
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29
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Park EC, Rongo C. The p38 MAP kinase pathway modulates the hypoxia response and glutamate receptor trafficking in aging neurons. eLife 2016; 5. [PMID: 26731517 PMCID: PMC4775213 DOI: 10.7554/elife.12010] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 01/04/2016] [Indexed: 01/07/2023] Open
Abstract
Neurons are sensitive to low oxygen (hypoxia) and employ a conserved pathway to combat its effects. Here, we show that p38 MAP Kinase (MAPK) modulates this hypoxia response pathway in C. elegans. Mutants lacking p38 MAPK components pmk-1 or sek-1 resemble mutants lacking the hypoxia response component and prolyl hydroxylase egl-9, with impaired subcellular localization of Mint orthologue LIN-10, internalization of glutamate receptor GLR-1, and depression of GLR-1-mediated behaviors. Loss of p38 MAPK impairs EGL-9 protein localization in neurons and activates the hypoxia-inducible transcription factor HIF-1, suggesting that p38 MAPK inhibits the hypoxia response pathway through EGL-9. As animals age, p38 MAPK levels decrease, resulting in GLR-1 internalization; this age-dependent downregulation can be prevented through either p38 MAPK overexpression or removal of CDK-5, an antagonizing kinase. Our findings demonstrate that p38 MAPK inhibits the hypoxia response pathway and determines how aging neurons respond to hypoxia through a novel mechanism. DOI:http://dx.doi.org/10.7554/eLife.12010.001 The brain accounts for 2% of our body weight, but consumes about 20% of our oxygen intake. This oxygen gluttony is due to the tremendous appetite of brain cells for energy, which neurons satisfy through oxygen-dependent (aerobic) metabolism. As a result, the loss of oxygen to the brain during a stroke, heart attack, or due to another medical condition can be very damaging to cells in the brain. Human and other animal cells use a communication system called the hypoxia response pathway to sense oxygen and trigger a protective response when oxygen is low. This pathway includes an enzyme called prolyl hydroxylase, which senses oxygen and modifies another protein in the pathway that regulates the production of enzymes involved in metabolism. This alters the balance of enzymes involved in aerobic and oxygen-independent (anaerobic) metabolism in the cell. However, it is not clear how the activity of the prolyl hydroxylase is regulated. Much of our knowledge about the hypoxia response pathway has been gained from studies using a small worm called C. elegans. This worm uses the pathway to cope with hypoxia in the harsh environment of the soil. Mutant worms that lack the prolyl hydroxylase have several abnormalities including higher levels of anaerobic metabolism even in the presence of oxygen, and defects in the connections between neurons. Park and Rongo used C. elegans to study the pathway in more detail. The experiments show that another enzyme called p38 MAPK activates the prolyl hydroxylase. Mutant worms that lack this enzyme have similar abnormalities in the hypoxia response pathway as animals that lack the prolyl hydroxylase. In normal worms, decreasing levels of p38 MAPK as the animals grow older contribute to the decline in the nervous system. The p38 MAPK enzyme appears to work by regulating the activity of the prolyl hydroxylase and its location inside neurons. These findings provide a new target for the development of drugs that may help to protect us from tissue damage caused by hypoxia. Future challenges are to find out what activates p38 MAPK, and how it influences the location of prolyl hydroxylase in neurons. DOI:http://dx.doi.org/10.7554/eLife.12010.002
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Affiliation(s)
- Eun Chan Park
- The Waksman Institute, Rutgers The State University of New Jersey, New Jersey, United States.,Department of Genetics, Rutgers The State University of New Jersey, New Jersey, United States
| | - Christopher Rongo
- The Waksman Institute, Rutgers The State University of New Jersey, New Jersey, United States.,Department of Genetics, Rutgers The State University of New Jersey, New Jersey, United States
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30
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Leiser SF, Miller H, Rossner R, Fletcher M, Leonard A, Primitivo M, Rintala N, Ramos FJ, Miller DL, Kaeberlein M. Cell nonautonomous activation of flavin-containing monooxygenase promotes longevity and health span. Science 2015; 350:1375-1378. [PMID: 26586189 DOI: 10.1126/science.aac9257] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 11/03/2015] [Indexed: 12/28/2022]
Abstract
Stabilization of the hypoxia-inducible factor 1 (HIF-1) increases life span and health span in nematodes through an unknown mechanism. We report that neuronal stabilization of HIF-1 mediates these effects in Caenorhabditis elegans through a cell nonautonomous signal to the intestine, which results in activation of the xenobiotic detoxification enzyme flavin-containing monooxygenase-2 (FMO-2). This prolongevity signal requires the serotonin biosynthetic enzyme TPH-1 in neurons and the serotonin receptor SER-7 in the intestine. Intestinal FMO-2 is also activated by dietary restriction (DR) and is necessary for DR-mediated life-span extension, which suggests that this enzyme represents a point of convergence for two distinct longevity pathways. FMOs are conserved in eukaryotes and induced by multiple life span-extending interventions in mice, which suggests that these enzymes may play a critical role in promoting health and longevity across phyla.
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Affiliation(s)
- Scott F Leiser
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Hillary Miller
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Ryan Rossner
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Marissa Fletcher
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Alison Leonard
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Melissa Primitivo
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Nicholas Rintala
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Fresnida J Ramos
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Dana L Miller
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Matt Kaeberlein
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
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31
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Abstract
Since the Von Hippel-Lindau (VHL) disease tumour suppressor gene VHL was identified in 1993 as the genetic basis for a rare disorder, it has proved to be of wide medical and scientific interest. VHL tumour suppressor protein (pVHL) plays a key part in cellular oxygen sensing by targeting hypoxia-inducible factors for ubiquitylation and proteasomal degradation. Early inactivation of VHL is commonly seen in clear-cell renal cell carcinoma (ccRCC), and insights gained from the functional analysis of pVHL have provided the foundation for the routine treatment of advanced-stage ccRCC with novel targeted therapies. However, recent sequencing studies have identified additional driver genes that are involved in the pathogenesis of ccRCC. As our understanding of the importance of VHL matures, it is timely to review progress from its initial description to current knowledge of VHL biology, as well as future prospects for novel medical treatments for VHL disease and ccRCC.
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Affiliation(s)
- Lucy Gossage
- 1] Cambridge University Hospitals NHS Foundation Trust, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK. [2] Department of Oncology, University of Cambridge, Box 193, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK. [3] Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Cambridge CB2 0RE, UK
| | - Tim Eisen
- 1] Cambridge University Hospitals NHS Foundation Trust, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK. [2] Department of Oncology, University of Cambridge, Box 193, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK
| | - Eamonn R Maher
- 1] Cambridge University Hospitals NHS Foundation Trust, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK. [2] Department of Medical Genetics, University of Cambridge and NIHR Cambridge Biomedical Research Centre, Box 238, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK
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32
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Bishop T, Ratcliffe PJ. Signaling hypoxia by hypoxia-inducible factor protein hydroxylases: a historical overview and future perspectives. HYPOXIA 2014; 2:197-213. [PMID: 27774477 PMCID: PMC5045067 DOI: 10.2147/hp.s47598] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
By the early 1900s, the close matching of oxygen supply with demand was recognized to be a fundamental requirement for physiological function, and multiple adaptive responses to environment hypoxia had been described. Nevertheless, the widespread operation of mechanisms that directly sense and respond to levels of oxygen in animal cells was not appreciated for most of the twentieth century with investigators generally stressing the regulatory importance of metabolic products. Work over the last 25 years has overturned that paradigm. It has revealed the existence of a set of “oxygen-sensing” 2-oxoglutarate dependent dioxygenases that catalyze the hydroxylation of specific amino acid residues and thereby control the stability and activity of hypoxia-inducible factor. The hypoxia-inducible factor hydroxylase pathway regulates a massive transcriptional cascade that is operative in essentially all animal cells. It transduces a wide range of responses to hypoxia, extending well beyond the classical boundaries of hypoxia physiology. Here we review the discovery and elucidation of these pathways, and consider the opportunities and challenges that have been brought into focus by the findings, including new implications for the integrated physiology of hypoxia and therapeutic approaches to ischemic/hypoxic disease.
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Affiliation(s)
- Tammie Bishop
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
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33
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Mans DA, Vermaat JS, Weijts BG, van Rooijen E, van Reeuwijk J, Boldt K, Daenen LGM, van der Groep P, Rowland BD, Jans JJ, Roepman R, Voest EE, van Diest PJ, Verhaar MC, de Bruin A, Giles RH. Regulation of E2F1 by the von Hippel-Lindau tumour suppressor protein predicts survival in renal cell cancer patients. J Pathol 2013; 231:117-29. [PMID: 23744542 DOI: 10.1002/path.4219] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Revised: 05/07/2013] [Accepted: 06/02/2013] [Indexed: 12/31/2022]
Abstract
Biallelic mutations of the von Hippel-Lindau (VHL) gene are the most common cause of sporadic and inherited renal cell carcinoma (RCC). Loss of VHL has been reported to affect cell proliferation by deregulating cell cycle-associated proteins. We report that the VHL gene product (pVHL) inhibits E2F1 expression at both mRNA and protein level in zebrafish and human RCC cells, while loss of VHL increases E2F1 expression in patient kidney tumour tissue and RCC cells, resulting in a delay of cell cycle progression. RCCs from von Hippel-Lindau patients with known germline VHL mutations express significantly more E2F1 compared to sporadic RCCs with either clear-cell (cc) or non-cc histology. Analysis of 138 primary RCCs reveals that E2F1 expression is significantly higher in tumours with a diameter ≤7 cm and with a favourable American Joint Committee on Cancer (AJCC) stage. The expression of E2F1 in RCC significantly correlates with p27 expression, suggesting that increased expression of E2F1 in RCC induces tumour cell senescence via p27. Cox regression analysis shows significant prediction of E2F1 expression for disease-free survival and overall survival, implying that E2F1 expression in kidney tumour is a novel prognostic factor for patients with RCC.
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Affiliation(s)
- Dorus A Mans
- Department of Medical Oncology, University Medical Centre Utrecht, Utrecht, The Netherlands
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34
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Gharbi H, Fabretti F, Bharill P, Rinschen MM, Brinkkötter S, Frommolt P, Burst V, Schermer B, Benzing T, Müller R. Loss of the Birt-Hogg-Dubé gene product folliculin induces longevity in a hypoxia-inducible factor-dependent manner. Aging Cell 2013; 12:593-603. [PMID: 23566034 DOI: 10.1111/acel.12081] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/28/2013] [Indexed: 01/09/2023] Open
Abstract
Signaling through the hypoxia-inducible factor hif-1 controls longevity, metabolism, and stress resistance in Caenorhabditis elegans. Hypoxia-inducible factor (HIF) protein levels are regulated through an evolutionarily conserved ubiquitin ligase complex. Mutations in the VHL gene, encoding a core component of this complex, cause a multitumor syndrome and renal cell carcinoma in humans. In the nematode, deficiency in vhl-1 promotes longevity mediated through HIF-1 stabilization. However, this longevity assurance pathway is not yet understood. Here, we identify folliculin (FLCN) as a novel interactor of the hif-1/vhl-1 longevity pathway. FLCN mutations cause Birt-Hogg-Dubé syndrome in humans, another tumor syndrome with renal tumorigenesis reminiscent of the VHL disease. Loss of the C. elegans ortholog of FLCN F22D3.2 significantly increased lifespan and enhanced stress resistance in a hif-1-dependent manner. F22D3.2, vhl-1, and hif-1 control longevity by a mechanism distinct from insulin-like signaling. Daf-16 deficiency did not abrogate the increase in lifespan mediated by flcn-1. These findings define FLCN as a player in HIF-dependent longevity signaling and connect organismal aging, stress resistance, and regulation of longevity with the formation of renal cell carcinoma.
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Affiliation(s)
- Hakam Gharbi
- Department 2 of Internal Medicine and Center for Molecular Medicine Cologne University of Cologne Cologne Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging‐Associated Diseases University of Cologne Cologne Germany
| | - Francesca Fabretti
- Department 2 of Internal Medicine and Center for Molecular Medicine Cologne University of Cologne Cologne Germany
| | - Puneet Bharill
- Department 2 of Internal Medicine and Center for Molecular Medicine Cologne University of Cologne Cologne Germany
| | - Markus M. Rinschen
- Department 2 of Internal Medicine and Center for Molecular Medicine Cologne University of Cologne Cologne Germany
| | - Sibylle Brinkkötter
- Department 2 of Internal Medicine and Center for Molecular Medicine Cologne University of Cologne Cologne Germany
| | - Peter Frommolt
- Cologne Excellence Cluster on Cellular Stress Responses in Aging‐Associated Diseases University of Cologne Cologne Germany
- Cologne Center for Genomics University of Cologne Cologne Germany
| | - Volker Burst
- Department 2 of Internal Medicine and Center for Molecular Medicine Cologne University of Cologne Cologne Germany
| | - Bernhard Schermer
- Department 2 of Internal Medicine and Center for Molecular Medicine Cologne University of Cologne Cologne Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging‐Associated Diseases University of Cologne Cologne Germany
- Systems Biology of Ageing Cologne University of Cologne Cologne Germany
| | - Thomas Benzing
- Department 2 of Internal Medicine and Center for Molecular Medicine Cologne University of Cologne Cologne Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging‐Associated Diseases University of Cologne Cologne Germany
- Systems Biology of Ageing Cologne University of Cologne Cologne Germany
| | - Roman‐Ulrich Müller
- Department 2 of Internal Medicine and Center for Molecular Medicine Cologne University of Cologne Cologne Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging‐Associated Diseases University of Cologne Cologne Germany
- Systems Biology of Ageing Cologne University of Cologne Cologne Germany
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35
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Eom HJ, Ahn JM, Kim Y, Choi J. Hypoxia inducible factor-1 (HIF-1)–flavin containing monooxygenase-2 (FMO-2) signaling acts in silver nanoparticles and silver ion toxicity in the nematode, Caenorhabditis elegans. Toxicol Appl Pharmacol 2013; 270:106-13. [DOI: 10.1016/j.taap.2013.03.028] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 03/19/2013] [Accepted: 03/23/2013] [Indexed: 01/30/2023]
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Saldanha JN, Parashar A, Pandey S, Powell-Coffman JA. Multiparameter behavioral analyses provide insights to mechanisms of cyanide resistance in Caenorhabditis elegans. Toxicol Sci 2013; 135:156-68. [PMID: 23805000 DOI: 10.1093/toxsci/kft138] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Environmental toxicants influence development, behavior, and ultimately survival. The nematode Caenorhabditis elegans has proven to be an exceptionally powerful model for toxicological studies. Here, we develop novel technologies to describe the effects of cyanide toxicity with high spatiotemporal resolution. Importantly, we use these methods to examine the genetic underpinnings of cyanide resistance. Caenorhabditis elegans that lack the EGL-9 oxygen sensing enzyme have been shown to be resistant to hydrogen cyanide (HCN) gas produced by the pathogen Pseudomonas aeruginosa PAO1. We demonstrate that the cyanide resistance exhibited by egl-9 mutants is completely dependent on the HIF-1 hypoxia-inducible factor and is mediated by the cysl-2 cysteine synthase, which likely functions in metabolic pathways that inactivate cyanide. Further, the expression of cysl-2 correlates with the degree of cyanide resistance exhibited in each genetic background. We find that each mutant exhibits similar relative resistance to HCN gas on plates or to aqueous potassium cyanide in microfluidic chambers. The design of the microfluidic devices, in combination with real-time imaging, addresses a series of challenges presented by mutant phenotypes and by the chemical nature of the toxicant. The microfluidic assay produces a set of behavioral parameters with increased resolution that describe cyanide toxicity and resistance in C. elegans, and this is particularly useful in analyzing subtle phenotypes. These multiparameter analyses of C. elegans behavior hold great potential as a means to monitor the effects of toxicants or chemical interventions in real time and to study the biological networks that underpin toxicant resistance.
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Affiliation(s)
- Jenifer N Saldanha
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa 50011, USA
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37
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Abstract
Over the last two decades molecular studies of inherited tumor syndromes that are associated with the development of kidney cancer have led to the identification of genes and biochemical pathways, which play key roles in the malignant transformation of renal epithelial cells. Some of these findings have broad biological impact and extend beyond renal cancer. This review's focus is on the von Hippel-Lindau (VHL)/hypoxia-inducible factor (HIF) oxygen-sensing pathway and its role in physiology, energy metabolism and tumorigenesis.
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Affiliation(s)
- Volker H Haase
- Department of Medicine, Vanderbilt School of Medicine, Nashville, TN 37232, USA.
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38
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Knockdown of von Hippel-Lindau protein decreases lung cancer cell proliferation and colonization. FEBS Lett 2012; 586:1510-5. [PMID: 22673518 DOI: 10.1016/j.febslet.2012.04.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Revised: 03/19/2012] [Accepted: 04/07/2012] [Indexed: 12/31/2022]
Abstract
Although von Hippel-Lindau protein (pVHL) is known as a tumor suppressor in kidney and other organs, it remains unclear whether pVHL plays a role in lung cancer development. We investigated the role of pVHL in lung cancer cell proliferation, migration, and colonization using stable A549 cells with knockdown of pVHL. We found that knockdown of pVHL promotes epithelial-mesenchymal transition (EMT) in lung cancer cells. Knockdown of pVHL decreased tumor colonization in a tail-vein injection model and decreased cell proliferation, whereas overexpression of constitutive active HIF increased tumor colonization, suggesting a HIF-independent function of pVHL in lung. Knockdown of pVHL decreased phosphorylation of FAK and expression of integrin, suggesting that pVHL regulates lung cancer development via integrin/FAK signaling pathway.
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Abstract
von Hippel–Lindau (VHL) disease is a hereditary cancer syndrome caused by inherited mutations that inactivate the VHL tumour suppressor gene. The VHL locus encodes pVHL, whose best studied function is to bind to and down-regulate the hypoxia-inducible factor (HIF) family of oxygen-dependent transcription factors. Early efforts have established the fundamental role of HIF in VHL-defective tumorigenesis and in particular renal cell carcinoma. However, recent findings have revealed an alternate side to the story, the HIF-independenttumour suppressor functions of pVHL. These include pVHL's ability to regulate apoptosis and senescence as well as its role in the maintenance of primary cilium and orchestrating the deposition of the extracellular matrix. To what extent these HIF-dependent and HIF-independent functions cooperate in VHL-defective tumorigenesis remains to be determined.
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Affiliation(s)
- Mingqing Li
- Departments of Medicine and Genetics, Division of Hematology/Oncology, Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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Abstract
Adaptation to hypoxia is a critical cellular event both in pathological settings, such as cancer and ischaemia, and in normal development and differentiation. Oxygen is thought to be not only an indispensable metabolic substrate for a variety of in vivo enzymatic reactions, including mitochondrial respiration, but also a key regulatory signal in tissue development and homeostasis by controlling a specific genetic program. Hypoxia-inducible transcription factors (HIFs) HIF-1 and HIF-2 are central mediators of the homeostatic response that enables cells to survive and differentiate in low-oxygen conditions. Genetically altered mice have been used to identify important roles for HIF-1 and HIF-2 as well as vascular endothelial growth factor (VEGF)-a potent angiogenic factor and a downstream target of the HIF pathway-in the regulation of skeletal development, bone homeostasis and haematopoiesis. In this Review, we summarize the current knowledge of HIF signalling in cartilage, bone and blood, and pay particular attention to the complex relationship between HIF and VEGF in these tissues revealed by data from research using animal models. The study of these models expands our understanding of the cell autonomous, paracrine and autocrine effects that mediate the homeostatic responses downstream of HIFs and VEGF.
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Ackerman D, Gems D. Insulin/IGF-1 and hypoxia signaling act in concert to regulate iron homeostasis in Caenorhabditis elegans. PLoS Genet 2012; 8:e1002498. [PMID: 22396654 PMCID: PMC3291539 DOI: 10.1371/journal.pgen.1002498] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2011] [Accepted: 12/09/2011] [Indexed: 01/08/2023] Open
Abstract
Iron plays an essential role in many biological processes, but also catalyzes the formation of reactive oxygen species (ROS), which can cause molecular damage. Iron homeostasis is therefore a critical determinant of fitness. In Caenorhabditis elegans, insulin/IGF-1 signaling (IIS) promotes growth and reproduction but limits stress resistance and lifespan through inactivation of the DAF-16/FoxO transcription factor (TF). We report that long-lived daf-2 insulin/IGF-1 receptor mutants show a daf-16–dependent increase in expression of ftn-1, which encodes the iron storage protein H-ferritin. To better understand the regulation of iron homeostasis, we performed a TF–limited genetic screen for factors influencing ftn-1 gene expression. The screen identified the heat-shock TF hsf-1, the MAD bHLH TF mdl-1, and the putative histone acetyl transferase ada-2 as activators of ftn-1 expression. It also revealed that the HIFα homolog hif-1 and its binding partner aha-1 (HIFβ) are potent repressors of ftn-1 expression. ftn-1 expression is induced by exposure to iron, and we found that hif-1 was required for this induction. In addition, we found that the prolyl hydroxylase EGL-9, which represses HIF-1 via the von Hippel-Lindau tumor suppressor VHL-1, can also act antagonistically to VHL-1 in regulating ftn-1. This suggests a novel mechanism for HIF target gene regulation by these evolutionarily conserved and clinically important hydroxylases. Our findings imply that the IIS and HIF pathways act together to regulate iron homeostasis in C. elegans. We suggest that IIS/DAF-16 regulation of ftn-1 modulates a trade-off between growth and stress resistance, as elevated iron availability supports growth but also increases ROS production. Iron plays a role in many biological processes, including energy generation and DNA replication. But to maintain health, levels of cellular iron must be just right: too much or too little iron can cause illnesses, such as anemia and hemochromatosis, respectively. Animals therefore carefully control their iron levels by regulating of iron uptake, transport, and storage within protein capsules called ferritins. But how do they coordinate this? Using the model organism C. elegans, we have discovered a network of genes and pathways that control iron homeostasis. We find that ferritin is regulated by insulin/IGF-1 signaling, which also controls growth and resistance to oxidative stress in response to harsh environmental conditions. Ferritin is also regulated by the hypoxia signaling pathway, which responds to oxygen and iron levels as well as to metabolic cues. We find that the hypoxia pathway acts as an iron sensor, a role it may also play in humans. Our work defines a network of signaling pathways that can adjust iron availability in response to a range of environmental cues. Understanding this network in C. elegans can help us to understand the causes of iron dyshomeostasis in humans, which can profoundly affect health.
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Affiliation(s)
- Daniel Ackerman
- Institute of Healthy Aging and Department of Genetics Evolution and Environment, University College London, London, United Kingdom
| | - David Gems
- Institute of Healthy Aging and Department of Genetics Evolution and Environment, University College London, London, United Kingdom
- * E-mail:
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Hypoxia regulates glutamate receptor trafficking through an HIF-independent mechanism. EMBO J 2012; 31:1379-93. [PMID: 22252129 DOI: 10.1038/emboj.2011.499] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Accepted: 12/23/2011] [Indexed: 12/14/2022] Open
Abstract
Oxygen influences behaviour in many organisms, with low levels (hypoxia) having devastating consequences for neuron survival. How neurons respond physiologically to counter the effects of hypoxia is not fully understood. Here, we show that hypoxia regulates the trafficking of the glutamate receptor GLR-1 in C. elegans neurons. Either hypoxia or mutations in egl-9, a prolyl hydroxylase cellular oxygen sensor, result in the internalization of GLR-1, the reduction of glutamate-activated currents, and the depression of GLR-1-mediated behaviours. Surprisingly, hypoxia-inducible factor (HIF)-1, the canonical substrate of EGL-9, is not required for this effect. Instead, EGL-9 interacts with the Mint orthologue LIN-10, a mediator of GLR-1 membrane recycling, to promote LIN-10 subcellular localization in an oxygen-dependent manner. The observed effects of hypoxia and egl-9 mutations require the activity of the proline-directed CDK-5 kinase and the CDK-5 phosphorylation sites on LIN-10, suggesting that EGL-9 and CDK-5 compete in an oxygen-dependent manner to regulate LIN-10 activity and thus GLR-1 trafficking. Our findings demonstrate a novel mechanism by which neurons sense and respond to hypoxia.
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Sherman TA, Rongali SC, Matthews TA, Pfeiffer J, Nehrke K. Identification of a nuclear carbonic anhydrase in Caenorhabditis elegans. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2012; 1823:808-17. [PMID: 22245567 DOI: 10.1016/j.bbamcr.2011.12.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Revised: 12/01/2011] [Accepted: 12/13/2011] [Indexed: 12/27/2022]
Abstract
BACKGROUND Carbonic anhydrases (CA) catalyze the inter-conversion of CO(2) with HCO(3) and H(+), and are involved in a wide variety of physiologic processes such as anion transport, pH regulation, and water balance. In mammals there are sixteen members of the classical α-type CA family, while the simple genetic model organism Caenorhabditis elegans codes for six αCA isoforms (cah-1 through cah-6). METHODS Fluorescent reporter constructs were used to analyze gene promoter usage, splice variation, and protein localization in transgenic worms. Catalytic activity of recombinant CA proteins was assessed using Hansson's histochemistry. CA's ability to regulate pH as a function of CO(2) and HCO(3) was measured using dynamic fluorescent imaging of genetically-targeted biosensors. RESULTS Each of the six CA genes was found to be expressed in a distinct repertoire of cell types. Surprisingly, worms also expressed a catalytically-active CA splice variant, cah-4a, in which an alternative first exon targeted the protein to the nucleus. Cah-4a expression was restricted mainly to the nervous system, where it was found in nearly all neurons, and recombinant CAH-4A protein could regulate pH in the nucleus. CONCLUSIONS In addition to establishing C. elegans as a platform for studying αCA function, this is the first example of a nuclear-targeted αCA in any organism to date. GENERAL SIGNIFICANCE A classical αCA isoform is targeted exclusively to the nucleus where its activity may impact nuclear physiologic and pathophysiologic responses.
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Affiliation(s)
- Teresa A Sherman
- Department of Medicine, University of Rochester Medical Center, Rochester, NY, USA
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Lai Y, Song M, Hakala K, Weintraub ST, Shiio Y. The interaction of the von Hippel-Lindau tumor suppressor and heterochromatin protein 1. Arch Biochem Biophys 2012; 518:103-10. [PMID: 22234250 DOI: 10.1016/j.abb.2011.12.023] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Revised: 12/20/2011] [Accepted: 12/23/2011] [Indexed: 10/14/2022]
Abstract
Inactivation of the von Hippel-Lindau (VHL) tumor suppressor is associated with renal carcinoma, hemangioblastoma and pheochromocytoma. The VHL protein is a component of a ubiquitin ligase complex that ubiquitinates and degrades hypoxia inducible factor-α (HIF-α). Degradation of HIF-α by VHL is proposed to suppress tumorigenesis and tumor angiogenesis. Several lines of evidence also suggest important roles for HIF-independent VHL functions in tumor suppression and other biological processes. Using GST-VHL pull-down experiment and mass spectrometry, we detected an interaction between VHL and heterochromatin protein 1 (HP1). We identified a conserved HP1-binding motif (PXVXL) in the β domain of VHL, which is disrupted in a renal carcinoma-associated P81S mutant. We show that the VHL P81S mutant displays reduced binding to HP1, yet retains the ability to interact with elongin B, elongin C, and cullin 2 and is fully capable of degrading HIF-α. We also demonstrate that HP1 increases the chromatin association of VHL. These results suggest a role for the VHL-HP1 interaction in VHL chromatin targeting.
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Affiliation(s)
- Yanlai Lai
- Greehey Children's Cancer Research Institute, The University of Texas Health Science Center, San Antonio, TX 78229-3900, USA
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Romney SJ, Newman BS, Thacker C, Leibold EA. HIF-1 regulates iron homeostasis in Caenorhabditis elegans by activation and inhibition of genes involved in iron uptake and storage. PLoS Genet 2011; 7:e1002394. [PMID: 22194696 PMCID: PMC3240588 DOI: 10.1371/journal.pgen.1002394] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2011] [Accepted: 10/10/2011] [Indexed: 12/31/2022] Open
Abstract
Caenorhabditis elegans ftn-1 and ftn-2, which encode the iron-storage protein ferritin, are transcriptionally inhibited during iron deficiency in intestine. Intestinal specific transcription is dependent on binding of ELT-2 to GATA binding sites in an iron-dependent enhancer (IDE) located in ftn-1 and ftn-2 promoters, but the mechanism for iron regulation is unknown. Here, we identify HIF-1 (hypoxia-inducible factor -1) as a negative regulator of ferritin transcription. HIF-1 binds to hypoxia-response elements (HREs) in the IDE in vitro and in vivo. Depletion of hif-1 by RNA interference blocks transcriptional inhibition of ftn-1 and ftn-2 reporters, and ftn-1 and ftn-2 mRNAs are not regulated in a hif-1 null strain during iron deficiency. An IDE is also present in smf-3 encoding a protein homologous to mammalian divalent metal transporter-1. Unlike the ftn-1 IDE, the smf-3 IDE is required for HIF-1–dependent transcriptional activation of smf-3 during iron deficiency. We show that hif-1 null worms grown under iron limiting conditions are developmentally delayed and that depletion of FTN-1 and FTN-2 rescues this phenotype. These data show that HIF-1 regulates intestinal iron homeostasis during iron deficiency by activating and inhibiting genes involved in iron uptake and storage. Due to its presence in proteins involved in hemoglobin synthesis, DNA synthesis, and mitochondrial respiration, eukaryotic cells require iron for survival. Excess iron can lead to oxidative damage, while iron deficiency reduces cell growth and causes cell death. Dysregulation of iron homeostasis in humans caused by iron deficiency or excess leads to anemia, diabetes, and neurodegenerative disorders. All organisms have thus developed mechanisms to sense, acquire, and store iron. We use Caenorhabditis elegans as a model organism to study mechanisms of iron regulation. Our previous studies show that the iron-storage protein ferritin (FTN-1, FTN-2) is transcriptionally inhibited in intestine during iron deficiency, but the mechanisms regulating iron regulation are not known. Here, we find that hypoxia-inducible factor 1 (HIF-1) transcriptionally inhibits ftn-1 and ftn-2 during iron deficiency. We also show that HIF-1 activates the iron uptake gene smf-3. Transcriptional activation and inhibition by HIF-1 is dependent on an iron enhancer in the promoters of these genes. HIF-1 is a known transcriptional activator, but its role in transcriptional inhibition is not well understood. Our data show that HIF-1 regulates iron homeostasis by activating and inhibiting iron uptake and storage genes, and they provide insight into HIF-1 transcriptional inhibition.
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Affiliation(s)
- Steven Joshua Romney
- Department of Medicine, University of Utah, Salt Lake City, Utah, United States of America
| | - Ben S. Newman
- University of Washington, Seattle, Washington, United States of America
| | - Colin Thacker
- Department of Biology, University of Utah, Salt Lake City, Utah, United States of America
| | - Elizabeth A. Leibold
- Department of Medicine, University of Utah, Salt Lake City, Utah, United States of America
- Department of Oncological Sciences, University of Utah, Salt Lake City, Utah, United States of America
- * E-mail:
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Lai Y, Song M, Hakala K, Weintraub ST, Shiio Y. Proteomic dissection of the von Hippel-Lindau (VHL) interactome. J Proteome Res 2011; 10:5175-82. [PMID: 21942715 DOI: 10.1021/pr200642c] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The von Hippel-Lindau (VHL) tumor suppressor gene encodes a component of a ubiquitin ligase complex containing elongin B, elongin C, cullin 2, and Rbx1, which acts as a negative regulator of hypoxia inducible factor (HIF). VHL ubiquitinates and degrades the alpha subunits of HIF, and this is proposed to suppress tumorigenesis and tumor angiogenesis. Several lines of evidence also suggest important roles for HIF-independent VHL functions in the maintenance of primary cilium, extracellular matrix formation, and tumor suppression. We undertook a series of proteomic analyses to gain a comprehensive picture of the VHL-interacting proteins. We found that the ARF tumor suppressor interacts with VHL30, a longer VHL isoform, but not with VHL19, a shorter VHL isoform. ARF was found to release VHL30 from the E3 ligase complex, promoting the binding of VHL30 to a protein arginine methyltransferase, PRMT3. Our analysis of the VHL19 interactome also uncovered that VHL19 displays an affinity to collagens and their biosynthesis enzymes.
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Affiliation(s)
- Yanlai Lai
- The University of Texas Health Science Center , San Antonio, TX 78229-3900, USA
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Complex cellular functions of the von Hippel-Lindau tumor suppressor gene: insights from model organisms. Oncogene 2011; 31:2247-57. [PMID: 21996733 DOI: 10.1038/onc.2011.442] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The von Hippel-Lindau tumor suppressor gene (VHL) has attracted intensive interest not only because its mutations predispose carriers to devastating tumors, but also because it is involved in oxygen sensing under physiological conditions. VHL loss-of-function mutations result in organ-specific tumors, such as hemangioblastoma of the central nervous system and renal cell carcinoma, both untreatable with conventional chemotherapies. The VHL protein is best known as an E3 ubiquitin ligase that targets hypoxia-inducible factor-α (HIF-α), but many diverse, non-canonical cellular functions have also been assigned to VHL, mainly based on studies in cell culture systems. As such, although the HIF-dependent role of VHL is critical, the full spectrum of pathophysiological functions of VHL is still unresolved. Such understanding requires careful cross-referencing with physiologically relevant experimental models. Studies in model systems, such as Caenorhabditis elegans, Drosophila, zebrafish and mouse have provided critical in vivo confirmation of the VHL-HIF pathway, and verification of potentially important cellular functions including microtubule stabilization and epithelial morphogenesis. More recently, animal models have also suggested systemic roles of VHL in hematopoiesis, metabolic homeostasis and inflammation. In this review, the studies performed in model organisms will be summarized and placed in context with existing clinical and in vitro data.
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48
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Hwang AB, Lee SJ. Regulation of life span by mitochondrial respiration: the HIF-1 and ROS connection. Aging (Albany NY) 2011; 3:304-10. [PMID: 21389351 PMCID: PMC3091523 DOI: 10.18632/aging.100292] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
A mild reduction in mitochondrial respiration extends the life span of many species, including C. elegans. We recently showed that hypoxia-inducible factor 1 (HIF-1) is required for the acquisition of a long life span by mutants with reduced respiration in C. elegans. We suggested that increased levels of reactive oxygen species (ROS) produced in the respiration mutants increase HIF-1 activity and lead to this longevity. In this research perspective, we discuss our findings and recent advances regarding the roles of ROS and HIF-1 in aging, focusing on the longevity caused by reduced respiration.
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Affiliation(s)
- Ara B Hwang
- Division of Molecular and Life Science, Pohang University of Science and Technology, Kyungbuk, South Korea
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49
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Leiser SF, Begun A, Kaeberlein M. HIF-1 modulates longevity and healthspan in a temperature-dependent manner. Aging Cell 2011; 10:318-26. [PMID: 21241450 DOI: 10.1111/j.1474-9726.2011.00672.x] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The hypoxia-inducible factor HIF-1 has recently been identified as an important modifier of longevity in the roundworm Caenorhabditis elegans. Studies have reported that HIF-1 can function as both a positive and negative regulator of life span, and several disparate models have been proposed for the role of HIF in aging. Here, we resolve many of the apparent discrepancies between these studies. We find that stabilization of HIF-1 increases life span robustly under all conditions tested; however, deletion of hif-1 increases life span in a temperature-dependent manner. Animals lacking HIF-1 are long lived at 25°C but not at 15°C. We further report that deletion or RNAi knockdown of hif-1 impairs healthspan at lower temperatures because of an age-dependent loss of vulval integrity. Deletion of hif-1 extends life span modestly at 20°C when animals displaying the vulval integrity defect are censored from the experimental data, but fails to extend life span if these animals are included. Knockdown of hif-1 results in nuclear relocalization of the FOXO transcription factor DAF-16, and DAF-16 is required for life span extension from deletion of hif-1 at all temperatures regardless of censoring.
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Affiliation(s)
- Scott F Leiser
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
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Lai Y, Qiao M, Song M, Weintraub ST, Shiio Y. Quantitative proteomics identifies the Myb-binding protein p160 as a novel target of the von Hippel-Lindau tumor suppressor. PLoS One 2011; 6:e16975. [PMID: 21386990 PMCID: PMC3046137 DOI: 10.1371/journal.pone.0016975] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Accepted: 01/11/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The von Hippel-Lindau (VHL) tumor suppressor gene encodes a component of a ubiquitin ligase complex, which is best understood as a negative regulator of hypoxia inducible factor (HIF). VHL ubiquitinates and degrades the α subunits of HIF, and this is proposed to suppress tumorigenesis and tumor angiogenesis. However, several lines of evidence suggest that there are unidentified substrates or targets for VHL that play important roles in tumor suppression. METHODOLOGY/PRINCIPAL FINDINGS Employing quantitative proteomics, we developed an approach to systematically identify the substrates of ubiquitin ligases and using this method, we identified the Myb-binding protein p160 as a novel substrate of VHL. CONCLUSIONS/SIGNIFICANCE A major barrier to understanding the functions of ubiquitin ligases has been the difficulty in pinpointing their ubiquitination substrates. The quantitative proteomics approach we devised for the identification of VHL substrates will be widely applicable to other ubiquitin ligases.
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Affiliation(s)
- Yanlai Lai
- Greehey Children's Cancer Research Institute, San Antonio, Texas, United States of America
| | - Mei Qiao
- Greehey Children's Cancer Research Institute, San Antonio, Texas, United States of America
| | - Meihua Song
- Greehey Children's Cancer Research Institute, San Antonio, Texas, United States of America
| | - Susan T. Weintraub
- Department of Biochemistry, The University of Texas Health Science Center, San Antonio, Texas, United States of America
| | - Yuzuru Shiio
- Greehey Children's Cancer Research Institute, San Antonio, Texas, United States of America
- Department of Biochemistry, The University of Texas Health Science Center, San Antonio, Texas, United States of America
- * E-mail:
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