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Hou W, Watson C, Cecconie T, Bolaki MN, Brady JJ, Lu Q, Gatto GJ, Day TA. Biochemical and functional characterization of the p.A165T missense variant of mitochondrial amidoxime-reducing component 1. J Biol Chem 2024; 300:107353. [PMID: 38723751 PMCID: PMC11190489 DOI: 10.1016/j.jbc.2024.107353] [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: 02/28/2024] [Revised: 04/25/2024] [Accepted: 05/03/2024] [Indexed: 06/07/2024] Open
Abstract
Recent genome-wide association studies have identified a missense variant p.A165T in mitochondrial amidoxime-reducing component 1 (mARC1) that is strongly associated with protection from all-cause cirrhosis and improved prognosis in nonalcoholic steatohepatitis. The precise mechanism of this protective effect is unknown. Substitution of alanine 165 with threonine is predicted to affect mARC1 protein stability and to have deleterious effects on its function. To investigate the mechanism, we have generated a knock-in mutant mARC1 A165T and a catalytically dead mutant C273A (as a control) in human hepatoma HepG2 cells, enabling characterization of protein subcellular distribution, stability, and biochemical functions of the mARC1 mutant protein expressed from its endogenous locus. Compared to WT mARC1, we found that the A165T mutant exhibits significant mislocalization outside of its traditional location anchored in the mitochondrial outer membrane and reduces protein stability, resulting in lower basal levels. We evaluated the involvement of the ubiquitin proteasome system in mARC1 A165T degradation and observed increased ubiquitination and faster degradation of the A165T variant. In addition, we have shown that HepG2 cells carrying the MTARC1 p.A165T variant exhibit lower N-reductive activity on exogenously added amidoxime substrates in vitro. The data from these biochemical and functional assays suggest a mechanism by which the MTARC1 p.A165T variant abrogates enzyme function which may contribute to its protective effect in liver disease.
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Affiliation(s)
- Wangfang Hou
- Respiratory and Immunology Biology Unit, GlaxoSmithKline, Collegeville, Pennsylvania, USA
| | - Christian Watson
- Respiratory and Immunology Biology Unit, GlaxoSmithKline, Collegeville, Pennsylvania, USA
| | - Ted Cecconie
- MEDDesign-NCE-MD SPMB US, GlaxoSmithKline, Collegeville, Pennsylvania, USA
| | | | | | - Quinn Lu
- Respiratory and Immunology Biology Unit, GlaxoSmithKline, Collegeville, Pennsylvania, USA
| | - Gregory J Gatto
- Respiratory and Immunology Biology Unit, GlaxoSmithKline, Collegeville, Pennsylvania, USA.
| | - Tovah A Day
- Department of Biology, Northeastern University, Boston, Massachusetts, USA
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2
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Zhu Y, Akkaya KC, Ruta J, Yokoyama N, Wang C, Ruwolt M, Lima DB, Lehmann M, Liu F. Cross-link assisted spatial proteomics to map sub-organelle proteomes and membrane protein topologies. Nat Commun 2024; 15:3290. [PMID: 38632225 PMCID: PMC11024108 DOI: 10.1038/s41467-024-47569-x] [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: 03/04/2023] [Accepted: 04/05/2024] [Indexed: 04/19/2024] Open
Abstract
The functions of cellular organelles and sub-compartments depend on their protein content, which can be characterized by spatial proteomics approaches. However, many spatial proteomics methods are limited in their ability to resolve organellar sub-compartments, profile multiple sub-compartments in parallel, and/or characterize membrane-associated proteomes. Here, we develop a cross-link assisted spatial proteomics (CLASP) strategy that addresses these shortcomings. Using human mitochondria as a model system, we show that CLASP can elucidate spatial proteomes of all mitochondrial sub-compartments and provide topological insight into the mitochondrial membrane proteome. Biochemical and imaging-based follow-up studies confirm that CLASP allows discovering mitochondria-associated proteins and revising previous protein sub-compartment localization and membrane topology data. We also validate the CLASP concept in synaptic vesicles, demonstrating its applicability to different sub-cellular compartments. This study extends the scope of cross-linking mass spectrometry beyond protein structure and interaction analysis towards spatial proteomics, and establishes a method for concomitant profiling of sub-organelle and membrane proteomes.
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Affiliation(s)
- Ying Zhu
- Department of Structural Biology, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Roessle-Str. 10 13125, Berlin, Germany
| | - Kerem Can Akkaya
- Department of Structural Biology, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Roessle-Str. 10 13125, Berlin, Germany
- Department of Molecular Physiology and Cell Biology, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Roessle-Str. 10 13125, Berlin, Germany
| | - Julia Ruta
- Department of Structural Biology, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Roessle-Str. 10 13125, Berlin, Germany
| | - Nanako Yokoyama
- Department of Structural Biology, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Roessle-Str. 10 13125, Berlin, Germany
| | - Cong Wang
- Department of Structural Biology, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Roessle-Str. 10 13125, Berlin, Germany
| | - Max Ruwolt
- Department of Structural Biology, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Roessle-Str. 10 13125, Berlin, Germany
| | - Diogo Borges Lima
- Department of Structural Biology, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Roessle-Str. 10 13125, Berlin, Germany
| | - Martin Lehmann
- Department of Molecular Physiology and Cell Biology, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Roessle-Str. 10 13125, Berlin, Germany
| | - Fan Liu
- Department of Structural Biology, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Roessle-Str. 10 13125, Berlin, Germany.
- Charité - Universitätsmedizin Berlin, Charitépl. 1, 10117, Berlin, Germany.
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Lai QC, Zheng J, Mou J, Cui CY, Wu QC, M Musa Rizvi S, Zhang Y, Li TM, Ren YB, Liu Q, Li Q, Zhang C. Identification of hub genes in calcific aortic valve disease. Comput Biol Med 2024; 172:108214. [PMID: 38508057 DOI: 10.1016/j.compbiomed.2024.108214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 01/26/2024] [Accepted: 02/25/2024] [Indexed: 03/22/2024]
Abstract
Calcific aortic valve disease (CAVD) is a heart valve disorder characterized primarily by calcification of the aortic valve, resulting in stiffness and dysfunction of the valve. CAVD is prevalent among aging populations and is linked to factors such as hypertension, dyslipidemia, tobacco use, and genetic predisposition, and can result in becoming a growing economic and health burden. Once aortic valve calcification occurs, it will inevitably progress to aortic stenosis. At present, there are no medications available that have demonstrated effectiveness in managing or delaying the progression of the disease. In this study, we mined four publicly available microarray datasets (GSE12644 GSE51472, GSE77287, GSE233819) associated with CAVD from the GEO database with the aim of identifying hub genes associated with the occurrence of CAVD and searching for possible biological targets for the early prevention and diagnosis of CAVD. This study provides preliminary evidence for therapeutic and preventive targets for CAVD and may provide a solid foundation for subsequent biological studies.
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Affiliation(s)
- Qian-Cheng Lai
- Department of Cardiothoracic Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China; Sichuan Provincial People's Hospital, Chengdu, 610000, Sichuan, China
| | - Jie Zheng
- Department of Anesthesiology, The Affiliated Traditional Chinese Medicine Hospital, Southwest Medical University, Luzhou, 646000, Sichuan, China
| | - Jian Mou
- Department of Anesthesiology, The Affiliated Traditional Chinese Medicine Hospital, Southwest Medical University, Luzhou, 646000, Sichuan, China; Department of Pain, The Affiliated Traditional Chinese Medicine Hospital, Southwest Medical University, Luzhou, 646000, Sichuan, China
| | - Chun-Yan Cui
- Department of Anesthesiology, The Affiliated Traditional Chinese Medicine Hospital, Southwest Medical University, Luzhou, 646000, Sichuan, China; Department of Pain, The Affiliated Traditional Chinese Medicine Hospital, Southwest Medical University, Luzhou, 646000, Sichuan, China
| | - Qing-Chen Wu
- Department of Cardiothoracic Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Syed M Musa Rizvi
- Department of Cardiothoracic Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Ying Zhang
- Department of Anesthesiology, The Affiliated Traditional Chinese Medicine Hospital, Southwest Medical University, Luzhou, 646000, Sichuan, China
| | - Tian-Mei Li
- Department of Anesthesiology, The Affiliated Traditional Chinese Medicine Hospital, Southwest Medical University, Luzhou, 646000, Sichuan, China
| | - Ying-Bo Ren
- Department of Anesthesiology, The Affiliated Traditional Chinese Medicine Hospital, Southwest Medical University, Luzhou, 646000, Sichuan, China
| | - Qing Liu
- Department of Pain, The Affiliated Traditional Chinese Medicine Hospital, Southwest Medical University, Luzhou, 646000, Sichuan, China; Hejiang Traditional Chinese Medicine Hospital, Luzhou, 646000, Sichuan, China.
| | - Qun Li
- Department of Pain, The Affiliated Traditional Chinese Medicine Hospital, Southwest Medical University, Luzhou, 646000, Sichuan, China.
| | - Cheng Zhang
- Department of Cardiothoracic Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
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Struwe MA, Scheidig AJ, Clement B. The mitochondrial amidoxime reducing component-from prodrug-activation mechanism to drug-metabolizing enzyme and onward to drug target. J Biol Chem 2023; 299:105306. [PMID: 37778733 PMCID: PMC10637980 DOI: 10.1016/j.jbc.2023.105306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 09/17/2023] [Accepted: 09/24/2023] [Indexed: 10/03/2023] Open
Abstract
The mitochondrial amidoxime-reducing component (mARC) is one of five known molybdenum enzymes in eukaryotes. mARC belongs to the MOSC domain superfamily, a large group of so far poorly studied molybdoenzymes. mARC was initially discovered as the enzyme activating N-hydroxylated prodrugs of basic amidines but has since been shown to also reduce a variety of other N-oxygenated compounds, for example, toxic nucleobase analogs. Under certain circumstances, mARC might also be involved in reductive nitric oxide synthesis through reduction of nitrite. Recently, mARC enzymes have received a lot of attention due to their apparent involvement in lipid metabolism and, in particular, because many genome-wide association studies have shown a common variant of human mARC1 to have a protective effect against liver disease. The mechanism linking mARC enzymes with lipid metabolism remains unknown. Here, we give a comprehensive overview of what is currently known about mARC enzymes, their substrates, structure, and apparent involvement in human disease.
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Affiliation(s)
- Michel A Struwe
- Zoologisches Institut - Strukturbiologie, Christian-Albrechts-Universität Kiel, Kiel, Germany; Pharmazeutisches Institut, Christian-Albrechts-Universität Kiel, Kiel, Germany.
| | - Axel J Scheidig
- Zoologisches Institut - Strukturbiologie, Christian-Albrechts-Universität Kiel, Kiel, Germany
| | - Bernd Clement
- Pharmazeutisches Institut, Christian-Albrechts-Universität Kiel, Kiel, Germany
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Clement B, Struwe MA. The History of mARC. Molecules 2023; 28:4713. [PMID: 37375270 DOI: 10.3390/molecules28124713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 06/08/2023] [Accepted: 06/10/2023] [Indexed: 06/29/2023] Open
Abstract
The mitochondrial amidoxime-reducing component (mARC) is the most recently discovered molybdoenzyme in humans after sulfite oxidase, xanthine oxidase and aldehyde oxidase. Here, the timeline of mARC's discovery is briefly described. The story begins with investigations into N-oxidation of pharmaceutical drugs and model compounds. Many compounds are N-oxidized extensively in vitro, but it turned out that a previously unknown enzyme catalyzes the retroreduction of the N-oxygenated products in vivo. After many years, the molybdoenzyme mARC could finally be isolated and identified in 2006. mARC is an important drug-metabolizing enzyme and N-reduction by mARC has been exploited very successfully for prodrug strategies, that allow oral administration of otherwise poorly bioavailable therapeutic drugs. Recently, it was demonstrated that mARC is a key factor in lipid metabolism and likely involved in the pathogenesis of non-alcoholic fatty liver disease (NAFLD). The exact link between mARC and lipid metabolism is not yet fully understood. Regardless, many now consider mARC a potential drug target for the prevention or treatment of liver diseases. This article focusses on discoveries related to mammalian mARC enzymes. mARC homologues have been studied in algae, plants and bacteria. These will not be discussed extensively here.
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Affiliation(s)
- Bernd Clement
- Pharmazeutisches Institut, Christian-Albrechts-Universität zu Kiel, Gutenbergstraße 76, 24118 Kiel, Germany
| | - Michel A Struwe
- Pharmazeutisches Institut, Christian-Albrechts-Universität zu Kiel, Gutenbergstraße 76, 24118 Kiel, Germany
- Zoologisches Institut-Strukturbiologie, Zentrum für Biochemie und Molekularbiologie, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany
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6
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Lewis LC, Chen L, Hameed LS, Kitchen RR, Maroteau C, Nagarajan SR, Norlin J, Daly CE, Szczerbinska I, Hjuler ST, Patel R, Livingstone EJ, Durrant TN, Wondimu E, BasuRay S, Chandran A, Lee WH, Hu S, Gilboa B, Grandi ME, Toledo EM, Erikat AH, Hodson L, Haynes WG, Pursell NW, Coppieters K, Fleckner J, Howson JM, Andersen B, Ruby MA. Hepatocyte mARC1 promotes fatty liver disease. JHEP Rep 2023; 5:100693. [PMID: 37122688 PMCID: PMC10133763 DOI: 10.1016/j.jhepr.2023.100693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 01/19/2023] [Accepted: 01/21/2023] [Indexed: 05/02/2023] Open
Abstract
Background & Aims Non-alcoholic fatty liver disease (NAFLD) has a prevalence of ∼25% worldwide, with significant public health consequences yet few effective treatments. Human genetics can help elucidate novel biology and identify targets for new therapeutics. Genetic variants in mitochondrial amidoxime-reducing component 1 (MTARC1) have been associated with NAFLD and liver-related mortality; however, its pathophysiological role and the cell type(s) mediating these effects remain unclear. We aimed to investigate how MTARC1 exerts its effects on NAFLD by integrating human genetics with in vitro and in vivo studies of mARC1 knockdown. Methods Analyses including multi-trait colocalisation and Mendelian randomisation were used to assess the genetic associations of MTARC1. In addition, we established an in vitro long-term primary human hepatocyte model with metabolic readouts and used the Gubra Amylin NASH (GAN)-diet non-alcoholic steatohepatitis mouse model treated with hepatocyte-specific N-acetylgalactosamine (GalNAc)-siRNA to understand the in vivo impacts of MTARC1. Results We showed that genetic variants within the MTARC1 locus are associated with liver enzymes, liver fat, plasma lipids, and body composition, and these associations are attributable to the same causal variant (p.A165T, rs2642438 G>A), suggesting a shared mechanism. We demonstrated that increased MTARC1 mRNA had an adverse effect on these traits using Mendelian randomisation, implying therapeutic inhibition of mARC1 could be beneficial. In vitro mARC1 knockdown decreased lipid accumulation and increased triglyceride secretion, and in vivo GalNAc-siRNA-mediated knockdown of mARC1 lowered hepatic but increased plasma triglycerides. We found alterations in pathways regulating lipid metabolism and decreased secretion of 3-hydroxybutyrate upon mARC1 knockdown in vitro and in vivo. Conclusions Collectively, our findings from human genetics, and in vitro and in vivo hepatocyte-specific mARC1 knockdown support the potential efficacy of hepatocyte-specific targeting of mARC1 for treatment of NAFLD. Impact and implications We report that genetically predicted increases in MTARC1 mRNA associate with poor liver health. Furthermore, knockdown of mARC1 reduces hepatic steatosis in primary human hepatocytes and a murine NASH model. Together, these findings further underscore the therapeutic potential of targeting hepatocyte MTARC1 for NAFLD.
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Affiliation(s)
| | | | | | | | | | - Shilpa R. Nagarajan
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Churchill Hospital, Oxford, UK
| | | | | | | | | | - Rahul Patel
- Novo Nordisk Research Centre Oxford, Oxford, UK
| | | | | | | | | | | | - Wan-Hung Lee
- Dicerna Pharmaceuticals Inc., Lexington, MA, USA
| | - Sile Hu
- Novo Nordisk Research Centre Oxford, Oxford, UK
| | | | | | | | | | - Leanne Hodson
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Churchill Hospital, Oxford, UK
- National Institute for Health Research Oxford Biomedical Research Centre, Oxford University Hospital Trusts, Oxford, UK
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7
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Yang J, Struwe M, Scheidig A, Mengell J, Clement B, Kirk ML. Active Site Structures of the Escherichia coli N-Hydroxylaminopurine Resistance Molybdoenzyme YcbX. Inorg Chem 2023; 62:5315-5319. [PMID: 36971376 PMCID: PMC10544827 DOI: 10.1021/acs.inorgchem.3c00342] [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] [Indexed: 03/29/2023]
Abstract
X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) data have been used to characterize the coordination environment for the catalytic Mo site of Escherichia coli YcbX in two different oxidation states. In the oxidized state, the Mo(VI) ion is coordinated by two terminal oxo ligands, a thiolate S atom from cysteine, and two S donors from the bidentate pyranopterin ene-1,2-dithiolate (pyranopterin dithiolene). Upon reduction, it is the more basic equatorial oxo ligand that is protonated, with a Mo-Oeq bond distance that is best described as either a short Mo4+-OH2 bond or a long Mo4+-OH bond. Mechanistic implications for substrate reduction are discussed in light of these structural details.
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Affiliation(s)
- Jing Yang
- Department of Chemistry and Chemical Biology, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, NM 87131-0001
| | - Michel Struwe
- Zoologisches Institut – Strukturbiologie, Zentrum für Biochemie und Molekularbiologie Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany
- Pharmazeutisches Institut, Christian-Albrechts-Universität zu Kiel, Gutenbergstraße 76, 24118 Kiel, Germany
| | - Axel Scheidig
- Zoologisches Institut – Strukturbiologie, Zentrum für Biochemie und Molekularbiologie Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany
| | - Joshua Mengell
- Department of Chemistry and Chemical Biology, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, NM 87131-0001
| | - Bernd Clement
- Pharmazeutisches Institut, Christian-Albrechts-Universität zu Kiel, Gutenbergstraße 76, 24118 Kiel, Germany
| | - Martin L. Kirk
- Department of Chemistry and Chemical Biology, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, NM 87131-0001
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8
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Wu D, Liang S, Guo H, Zhang S, Yang G, Yuan Y, Liu L. Downregulation of MARC2 Promotes Immune Escape and Is Associated With Immunosuppression of Hepatocellular Carcinoma. Front Genet 2022; 12:790093. [PMID: 35173763 PMCID: PMC8841793 DOI: 10.3389/fgene.2021.790093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 12/27/2021] [Indexed: 11/17/2022] Open
Abstract
The N-reductive enzyme system (NRES), composed of MARC1, MARC2, CYB5, and CYB5R, is responsible for the reduction of N-oxygenated compounds and participates in several physiological processes. For example, MARC2 serves as an important prognostic indicator and is downregulated in hepatocellular carcinoma, and the downregulation of MARC2 is critical to the regulation of lipid metabolism and cell cycle progression. However, the role of MARC2 in tumor immune microenvironment modification had not previously been investigated. In this study, we found that downregulation of MARC2 was associated with the differentiation of CD4+T cells into regulatory T cells (Tregs). Furthermore, restoring the expression of MARC2 could increase the expression of HLA-C and B2M via PPARA-related lipid metabolism signaling pathways, which could facilitate tumor antigen presentation to the tumor-infiltrating T cells. Additionally, MARC2 expression negatively correlated with several immune checkpoints. The immune checkpoint burden was generated based on 28 MARC2-related immune checkpoints. Patients with a higher immune checkpoint burden were predicted to have a poorer prognosis and a lower level of activated CD8+ T cells. The results showed that expression of the NRES is a prognostic indicator of hepatocellular carcinoma and MARC2 contributes significantly to predict the prognosis. Finally, loss of MARC2 in HCC patients was found to facilitate immune escape and was associated with immunosuppression.
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Affiliation(s)
- Dehai Wu
- Department of Hepatic Surgery, Key Laboratory of Hepatosplenic Surgery, Ministry of Education, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Shuhang Liang
- Department of Hepatic Surgery, Key Laboratory of Hepatosplenic Surgery, Ministry of Education, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Hongrui Guo
- Department of Hepatic Surgery, Key Laboratory of Hepatosplenic Surgery, Ministry of Education, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Shugeng Zhang
- Department of Hepatic Surgery, Key Laboratory of Hepatosplenic Surgery, Ministry of Education, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Guangchao Yang
- Department of Hepatic Surgery, Key Laboratory of Hepatosplenic Surgery, Ministry of Education, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Yubin Yuan
- Department of Hepatic Surgery, Key Laboratory of Hepatosplenic Surgery, Ministry of Education, The First Affiliated Hospital of Harbin Medical University, Harbin, China
- Department of General Surgery, Heze Municipal Hospital, Heze, China
| | - Lianxin Liu
- Department of Hepatic Surgery, Key Laboratory of Hepatosplenic Surgery, Ministry of Education, The First Affiliated Hospital of Harbin Medical University, Harbin, China
- *Correspondence: Lianxin Liu,
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9
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Yuan S, Hahn SA, Miller MP, Sanker S, Calderon MJ, Sullivan M, Dosunmu-Ogunbi AM, Fazzari M, Li Y, Reynolds M, Wood KC, St Croix CM, Stolz D, Cifuentes-Pagano E, Navas P, Shiva S, Schopfer FJ, Pagano PJ, Straub AC. Cooperation between CYB5R3 and NOX4 via coenzyme Q mitigates endothelial inflammation. Redox Biol 2021; 47:102166. [PMID: 34656824 PMCID: PMC8577475 DOI: 10.1016/j.redox.2021.102166] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 09/03/2021] [Accepted: 09/06/2021] [Indexed: 12/12/2022] Open
Abstract
NADPH oxidase 4 (NOX4) regulates endothelial inflammation by producing hydrogen peroxide (H2O2) and to a lesser extent O2•-. The ratio of NOX4-derived H2O2 and O2•- can be altered by coenzyme Q (CoQ) mimics. Therefore, we hypothesize that cytochrome b5 reductase 3 (CYB5R3), a CoQ reductase abundant in vascular endothelial cells, regulates inflammatory activation. To examine endothelial CYB5R3 in vivo, we created tamoxifen-inducible endothelium-specific Cyb5r3 knockout mice (R3 KO). Radiotelemetry measurements of systolic blood pressure showed systemic hypotension in lipopolysaccharides (LPS) challenged mice, which was exacerbated in R3 KO mice. Meanwhile, LPS treatment caused greater endothelial dysfunction in R3 KO mice, evaluated by acetylcholine-induced vasodilation in the isolated aorta, accompanied by elevated mRNA expression of vascular adhesion molecule 1 (Vcam-1). Similarly, in cultured human aortic endothelial cells (HAEC), LPS and tumor necrosis factor α (TNF-α) induced VCAM-1 protein expression was enhanced by Cyb5r3 siRNA, which was ablated by silencing the Nox4 gene simultaneously. Moreover, super-resolution confocal microscopy indicated mitochondrial co-localization of CYB5R3 and NOX4 in HAECs. APEX2-based electron microscopy and proximity biotinylation also demonstrated CYB5R3's localization on the mitochondrial outer membrane and its interaction with NOX4, which was further confirmed by the proximity ligation assay. Notably, Cyb5r3 knockdown HAECs showed less total H2O2 but more mitochondrial O2•-. Using inactive or non-membrane bound active CYB5R3, we found that CYB5R3 activity and membrane translocation are needed for optimal generation of H2O2 by NOX4. Lastly, cells lacking the CoQ synthesizing enzyme COQ6 showed decreased NOX4-derived H2O2, indicating a requirement for endogenous CoQ in NOX4 activity. In conclusion, CYB5R3 mitigates endothelial inflammatory activation by assisting in NOX4-dependent H2O2 generation via CoQ.
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Affiliation(s)
- Shuai Yuan
- Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Scott A Hahn
- Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Megan P Miller
- Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Subramaniam Sanker
- Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Michael J Calderon
- Center for Biologic Imaging, University of Pittsburgh, Pittsburgh, PA, USA
| | - Mara Sullivan
- Center for Biologic Imaging, University of Pittsburgh, Pittsburgh, PA, USA
| | - Atinuke M Dosunmu-Ogunbi
- Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA, USA; Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Marco Fazzari
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Yao Li
- Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Michael Reynolds
- Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Katherine C Wood
- Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | | | - Donna Stolz
- Center for Biologic Imaging, University of Pittsburgh, Pittsburgh, PA, USA
| | - Eugenia Cifuentes-Pagano
- Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA, USA; Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Placido Navas
- Centro Andaluz de Biología del Desarrollo and CIBERER, Instituto de Salud Carlos III, Universidad Pablo de Olavide-CSIC-JA, Sevilla, Spain, Spain
| | - Sruti Shiva
- Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA, USA; Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Francisco J Schopfer
- Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA, USA; Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA; Pittsburgh Liver Research Center (PLRC), University of Pittsburgh, Pittsburgh, PA, USA
| | - Patrick J Pagano
- Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA, USA; Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Adam C Straub
- Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA, USA; Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA; Center for Microvascular Research, University of Pittsburgh, Pittsburgh, PA, USA.
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10
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Peng L, Ma W, Xie Q, Chen B. Identification and validation of hub genes for diabetic retinopathy. PeerJ 2021; 9:e12126. [PMID: 34603851 PMCID: PMC8445088 DOI: 10.7717/peerj.12126] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 08/17/2021] [Indexed: 12/23/2022] Open
Abstract
Background Diabetic retinopathy (DR) is characterized by a gradually progressive alteration in the retinal microvasculature that leads to middle-aged adult acquired persistent blindness. Limited research has been conducted on DR pathogenesis at the gene level. Thus, we aimed to reveal novel key genes that might be associated with DR formation via a bioinformatics analysis. Methods The GSE53257 dataset from the Gene Expression Omnibus was downloaded for gene co-expression analysis. We identified significant gene modules via the Weighted Gene Co-expression Network Analysis, which was conducted by the Protein-Protein Interaction (PPI) Network via Cytoscape and from this we screened for key genes and gene sets for particular functional and pathway-specific enrichments. The hub gene expression was verified by real-time PCR in DR rats modeling and an external database. Results Two significant gene modules were identified. Significant key genes were predominantly associated with mitochondrial function, fatty acid oxidation and oxidative stress. Among all key genes analyzed, six up-regulated genes (i.e., SLC25A33, NDUFS1, MRPS23, CYB5R1, MECR, and MRPL15) were highly and significantly relevant in the context of DR formation. The PCR results showed that SLC25A33 and NDUFS1 expression were increased in DR rats modeling group. Conclusion Gene co-expression network analysis highlights the importance of mitochondria and oxidative stress in the pathophysiology of DR. DR co-expressing gene module was constructed and key genes were identified, and both SLC25A33 and NDUFS1 may serve as potential biomarker and therapeutic target for DR.
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Affiliation(s)
- Li Peng
- Department of Ophthalmology, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China.,Department of Ophthalmology, Central South University Xiangya School of Medicine Affiliated Haikou Hospital, Haikou, Hainan, China
| | - Wei Ma
- Department of Ophthalmology, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Qing Xie
- Department of Ophthalmology, Central South University Xiangya School of Medicine Affiliated Haikou Hospital, Haikou, Hainan, China
| | - Baihua Chen
- Department of Ophthalmology, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
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11
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Wei L, Zheng YY, Sun J, Wang P, Tao T, Li Y, Chen X, Sang Y, Chong D, Zhao W, Zhou Y, Wang Y, Jiang Z, Qiu T, Li CJ, Zhu MS, Zhang X. GGPP depletion initiates metaflammation through disequilibrating CYB5R3-dependent eicosanoid metabolism. J Biol Chem 2020; 295:15988-16001. [PMID: 32913122 DOI: 10.1074/jbc.ra120.015020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 08/20/2020] [Indexed: 12/30/2022] Open
Abstract
Metaflammation is a primary inflammatory complication of metabolic disorders characterized by altered production of many inflammatory cytokines, adipokines, and lipid mediators. Whereas multiple inflammation networks have been identified, the mechanisms by which metaflammation is initiated have long been controversial. As the mevalonate pathway (MVA) produces abundant bioactive isoprenoids and abnormal MVA has a phenotypic association with inflammation/immunity, we speculate that isoprenoids from the MVA may provide a causal link between metaflammation and metabolic disorders. Using a line with the MVA isoprenoid producer geranylgeranyl diphosphate synthase (GGPPS) deleted, we find that geranylgeranyl pyrophosphate (GGPP) depletion causes an apparent metaflammation as evidenced by abnormal accumulation of fatty acids, eicosanoid intermediates, and proinflammatory cytokines. We also find that GGPP prenylate cytochrome b 5 reductase 3 (CYB5R3) and the prenylated CYB5R3 then translocate from the mitochondrial to the endoplasmic reticulum (ER) pool. As CYB5R3 is a critical NADH-dependent reductase necessary for eicosanoid metabolism in ER, we thus suggest that GGPP-mediated CYB5R3 prenylation is necessary for metabolism. In addition, we observe that pharmacological inhibition of the MVA pathway by simvastatin is sufficient to inhibit CYB5R3 translocation and induces smooth muscle death. Therefore, we conclude that the dysregulation of MVA intermediates is an essential mechanism for metaflammation initiation, in which the imbalanced production of eicosanoid intermediates in the ER serve as an important pathogenic factor. Moreover, the interplay of MVA and eicosanoid metabolism as we reported here illustrates a model for the coordinating regulation among metabolite pathways.
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Affiliation(s)
- Lisha Wei
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center and Medical School of Nanjing University and Nanjing Drum Tower Hospital Affiliated with Nanjing University Medical School, Nanjing University, Nanjing, China
| | - Yan-Yan Zheng
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center and Medical School of Nanjing University and Nanjing Drum Tower Hospital Affiliated with Nanjing University Medical School, Nanjing University, Nanjing, China
| | - Jie Sun
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center and Medical School of Nanjing University and Nanjing Drum Tower Hospital Affiliated with Nanjing University Medical School, Nanjing University, Nanjing, China
| | - Pei Wang
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center and Medical School of Nanjing University and Nanjing Drum Tower Hospital Affiliated with Nanjing University Medical School, Nanjing University, Nanjing, China
| | - Tao Tao
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center and Medical School of Nanjing University and Nanjing Drum Tower Hospital Affiliated with Nanjing University Medical School, Nanjing University, Nanjing, China
| | - Yeqiong Li
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center and Medical School of Nanjing University and Nanjing Drum Tower Hospital Affiliated with Nanjing University Medical School, Nanjing University, Nanjing, China
| | - Xin Chen
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center and Medical School of Nanjing University and Nanjing Drum Tower Hospital Affiliated with Nanjing University Medical School, Nanjing University, Nanjing, China
| | - Yongjuan Sang
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center and Medical School of Nanjing University and Nanjing Drum Tower Hospital Affiliated with Nanjing University Medical School, Nanjing University, Nanjing, China
| | - Danyang Chong
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center and Medical School of Nanjing University and Nanjing Drum Tower Hospital Affiliated with Nanjing University Medical School, Nanjing University, Nanjing, China
| | - Wei Zhao
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center and Medical School of Nanjing University and Nanjing Drum Tower Hospital Affiliated with Nanjing University Medical School, Nanjing University, Nanjing, China
| | - Yuwei Zhou
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center and Medical School of Nanjing University and Nanjing Drum Tower Hospital Affiliated with Nanjing University Medical School, Nanjing University, Nanjing, China
| | - Ye Wang
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center and Medical School of Nanjing University and Nanjing Drum Tower Hospital Affiliated with Nanjing University Medical School, Nanjing University, Nanjing, China
| | - Zhihui Jiang
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center and Medical School of Nanjing University and Nanjing Drum Tower Hospital Affiliated with Nanjing University Medical School, Nanjing University, Nanjing, China
| | - Tiantian Qiu
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center and Medical School of Nanjing University and Nanjing Drum Tower Hospital Affiliated with Nanjing University Medical School, Nanjing University, Nanjing, China
| | - Chao-Jun Li
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center and Medical School of Nanjing University and Nanjing Drum Tower Hospital Affiliated with Nanjing University Medical School, Nanjing University, Nanjing, China.
| | - Min-Sheng Zhu
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center and Medical School of Nanjing University and Nanjing Drum Tower Hospital Affiliated with Nanjing University Medical School, Nanjing University, Nanjing, China.
| | - Xuena Zhang
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center and Medical School of Nanjing University and Nanjing Drum Tower Hospital Affiliated with Nanjing University Medical School, Nanjing University, Nanjing, China.
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12
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Wu D, Wang Y, Yang G, Zhang S, Liu Y, Zhou S, Guo H, Liang S, Cui Y, Zhang B, Ma K, Zhang C, Liu Y, Sun L, Wang J, Liu L. A novel mitochondrial amidoxime reducing component 2 is a favorable indicator of cancer and suppresses the progression of hepatocellular carcinoma by regulating the expression of p27. Oncogene 2020; 39:6099-6112. [PMID: 32811980 PMCID: PMC7498369 DOI: 10.1038/s41388-020-01417-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 07/23/2020] [Accepted: 08/04/2020] [Indexed: 12/03/2022]
Abstract
Hepatocellular carcinoma (HCC) is the fifth leading cause of cancer-related mortality in the United States. Exploring the mechanism of HCC and identifying ideal targets is critical. In the present study, we demonstrated metabolism dysfunction might be a key diver for the development of HCC. The mitochondrial amidoxime reducing component 2 (MARC2) as a newly discovered molybdenum enzyme was downregulated in human HCC tissues and HCC cells. Downregulated MARC2 was significantly associated with clinicopathological characteristics of HCC, such as tumor size, AFP levels, and tumor grade and was an independent risk factor of poor prognosis. Both in vitro and in vivo studies suggested that MARC2 suppressed the progression of HCC by regulating the protein expression level of p27. The Hippo signaling pathway and RNF123 were required for this process. Moreover, MARC2 regulated expression of HNF4A via the Hippo signaling pathway. HNF4A was recruited to the promoter of MARC2 forming a feedback loop. MARC2 levels were downregulated by methylation. We demonstrated the prognostic value of MARC2 in HCC and determined the mechanism by which MARC2 suppressed the progression of HCC in this study. These findings may lead to new therapeutic targets for HCC.
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Affiliation(s)
- Dehai Wu
- Department of Hepatic Surgery, Key Laboratory of Hepatosplenic Surgery, Ministry of Education, The First Affiliated Hospital of Harbin Medical University, Harbin, 150001, Heilongjiang, China
| | - Yan Wang
- Department of Colorectal Surgery, Harbin Medical University Cancer Hospital, Harbin, 150001, Heilongjiang, China
| | - Guangchao Yang
- Department of Hepatic Surgery, Key Laboratory of Hepatosplenic Surgery, Ministry of Education, The First Affiliated Hospital of Harbin Medical University, Harbin, 150001, Heilongjiang, China
| | - Shugeng Zhang
- Department of Hepatic Surgery, Key Laboratory of Hepatosplenic Surgery, Ministry of Education, The First Affiliated Hospital of Harbin Medical University, Harbin, 150001, Heilongjiang, China
| | - Yao Liu
- Division of Life Sciences and Medicine, Department of Hepatobiliary Surgery, Anhui Province Key Laboratory of Hepatopancreatobiliary Surgery, The First Affiliated Hospital of USTC, University of Science and Technology of China, Heifei, 230001, Anhui, China
| | - Shuo Zhou
- Department of Hepatic Surgery, Key Laboratory of Hepatosplenic Surgery, Ministry of Education, The First Affiliated Hospital of Harbin Medical University, Harbin, 150001, Heilongjiang, China
| | - Hongrui Guo
- Department of Hepatic Surgery, Key Laboratory of Hepatosplenic Surgery, Ministry of Education, The First Affiliated Hospital of Harbin Medical University, Harbin, 150001, Heilongjiang, China
| | - Shuhang Liang
- Department of Hepatic Surgery, Key Laboratory of Hepatosplenic Surgery, Ministry of Education, The First Affiliated Hospital of Harbin Medical University, Harbin, 150001, Heilongjiang, China
| | - Yifeng Cui
- Department of Hepatic Surgery, Key Laboratory of Hepatosplenic Surgery, Ministry of Education, The First Affiliated Hospital of Harbin Medical University, Harbin, 150001, Heilongjiang, China
| | - Bo Zhang
- Department of Hepatic Surgery, Key Laboratory of Hepatosplenic Surgery, Ministry of Education, The First Affiliated Hospital of Harbin Medical University, Harbin, 150001, Heilongjiang, China
| | - Kun Ma
- Department of Hepatic Surgery, Key Laboratory of Hepatosplenic Surgery, Ministry of Education, The First Affiliated Hospital of Harbin Medical University, Harbin, 150001, Heilongjiang, China
| | - Congyi Zhang
- Department of Hepatic Surgery, Key Laboratory of Hepatosplenic Surgery, Ministry of Education, The First Affiliated Hospital of Harbin Medical University, Harbin, 150001, Heilongjiang, China
| | - Yufeng Liu
- Department of Hepatic Surgery, Key Laboratory of Hepatosplenic Surgery, Ministry of Education, The First Affiliated Hospital of Harbin Medical University, Harbin, 150001, Heilongjiang, China
| | - Linmao Sun
- Department of Hepatic Surgery, Key Laboratory of Hepatosplenic Surgery, Ministry of Education, The First Affiliated Hospital of Harbin Medical University, Harbin, 150001, Heilongjiang, China
| | - Jiabei Wang
- Division of Life Sciences and Medicine, Department of Hepatobiliary Surgery, Anhui Province Key Laboratory of Hepatopancreatobiliary Surgery, The First Affiliated Hospital of USTC, University of Science and Technology of China, Heifei, 230001, Anhui, China.
| | - Lianxin Liu
- Department of Hepatic Surgery, Key Laboratory of Hepatosplenic Surgery, Ministry of Education, The First Affiliated Hospital of Harbin Medical University, Harbin, 150001, Heilongjiang, China.
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13
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Indorf P, Kubitza C, Scheidig AJ, Kunze T, Clement B. Drug Metabolism by the Mitochondrial Amidoxime Reducing Component (mARC): Rapid Assay and Identification of New Substrates. J Med Chem 2020; 63:6538-6546. [PMID: 31790578 DOI: 10.1021/acs.jmedchem.9b01483] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
For the development of new drugs, the investigation of their metabolism is of central importance. In the past, the focus was mostly on the consideration of established enzymes leading to oxidations such as cytochrome P450. However, reductive metabolism by the mARC enzyme system can play an important role in particular for nitrogen containing functional groups. A rapid test was established to give developers of new drugs in the preclinical stage the opportunity to test the metabolism by mARC. To demonstrate the relevance and validity of the new test system, known and potential substrates were applied to this new assay. All known substrates could be detected by the system. Furthermore, several new substrates were found including long-established drugs such as hydroxyurea and new compounds in development such as epacdadostat.
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Affiliation(s)
- Patrick Indorf
- Pharmaceutical Institute-Medicinal Chemistry, Christian-Albrechts-University Kiel, Gutenbergstraße 76, 24118 Kiel, Germany
| | - Christian Kubitza
- Zoological Institute-Structural Biology, Christian-Albrechts-University Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany
| | - Axel J Scheidig
- Zoological Institute-Structural Biology, Christian-Albrechts-University Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany
| | - Thomas Kunze
- Pharmaceutical Institute-Medicinal Chemistry, Christian-Albrechts-University Kiel, Gutenbergstraße 76, 24118 Kiel, Germany
| | - Bernd Clement
- Pharmaceutical Institute-Medicinal Chemistry, Christian-Albrechts-University Kiel, Gutenbergstraße 76, 24118 Kiel, Germany
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14
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Rixen S, Havemeyer A, Tyl-Bielicka A, Pysniak K, Gajewska M, Kulecka M, Ostrowski J, Mikula M, Clement B. Mitochondrial amidoxime-reducing component 2 (MARC2) has a significant role in N-reductive activity and energy metabolism. J Biol Chem 2019; 294:17593-17602. [PMID: 31554661 DOI: 10.1074/jbc.ra119.007606] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 09/19/2019] [Indexed: 01/29/2023] Open
Abstract
The mitochondrial amidoxime-reducing component (MARC) is a mammalian molybdenum-containing enzyme. All annotated mammalian genomes harbor two MARC genes, MARC1 and MARC2, which share a high degree of sequence similarity. Both molybdoenzymes reduce a variety of N-hydroxylated compounds. Besides their role in N-reductive drug metabolism, only little is known about their physiological functions. In this study, we characterized an existing KO mouse model lacking the functional MARC2 gene and fed a high-fat diet and also performed in vivo and in vitro experiments to characterize reductase activity toward known MARC substrates. MARC2 KO significantly decreased reductase activity toward several N-oxygenated substrates, and for typical MARC substrates, only small residual reductive activity was still detectable in MARC2 KO mice. The residual detected reductase activity in MARC2 KO mice could be explained by MARC1 expression that was hardly unaffected by KO, and we found no evidence of significant activity of other reductase enzymes. These results clearly indicate that MARC2 is mainly responsible for N-reductive biotransformation in mice. Striking phenotypical features of MARC2 KO mice were lower body weight, increased body temperature, decreased levels of total cholesterol, and increased glucose levels, supporting previous findings that MARC2 affects energy pathways. Of note, the MARC2 KO mice were resistant to high-fat diet-induced obesity. We propose that the MARC2 KO mouse model could be a powerful tool for predicting MARC-mediated drug metabolism and further investigating MARC's roles in energy homeostasis.
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Affiliation(s)
- Sophia Rixen
- Department of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Christian Albrechts University, 24118 Kiel, Germany
| | - Antje Havemeyer
- Department of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Christian Albrechts University, 24118 Kiel, Germany
| | - Anita Tyl-Bielicka
- Department of Genetics, Maria Sklodowska-Curie Institute, Cancer Center, 02-781 Warsaw, Poland
| | - Kazimiera Pysniak
- Department of Genetics, Maria Sklodowska-Curie Institute, Cancer Center, 02-781 Warsaw, Poland
| | - Marta Gajewska
- Department of Genetics, Maria Sklodowska-Curie Institute, Cancer Center, 02-781 Warsaw, Poland
| | - Maria Kulecka
- Department of Gastroenterology, Hepatology, and Clinical Oncology, Centre of Postgraduate Medical Education, 02-781 Warsaw, Poland
| | - Jerzy Ostrowski
- Department of Genetics, Maria Sklodowska-Curie Institute, Cancer Center, 02-781 Warsaw, Poland.,Department of Gastroenterology, Hepatology, and Clinical Oncology, Centre of Postgraduate Medical Education, 02-781 Warsaw, Poland
| | - Michal Mikula
- Department of Genetics, Maria Sklodowska-Curie Institute, Cancer Center, 02-781 Warsaw, Poland
| | - Bernd Clement
- Department of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Christian Albrechts University, 24118 Kiel, Germany
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15
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LINC00116 codes for a mitochondrial peptide linking respiration and lipid metabolism. Proc Natl Acad Sci U S A 2019; 116:4940-4945. [PMID: 30796188 PMCID: PMC6421467 DOI: 10.1073/pnas.1809105116] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Short peptides are encoded in genomes of all organisms and have important functions. Due to the small size of such open reading frames, they are frequently overlooked by automatic genome annotation. We investigated the gene that was misannotated as long noncoding RNA LINC00116 and demonstrated that this gene codes for a 56-amino-acid-long peptide, Mtln, which is localized in mitochondria. Inactivation of the Mtln coding gene leads to reduction of oxygen consumption attributed to respiratory complex I activity and perturbs lipid composition of the cell. This influence is mediated by Mtln interaction with NADH-dependent cytochrome b5 reductase. Disruption of the mitochondrial localization of the latter phenocopies Mtln inactivation. Genes coding for small peptides have been frequently misannotated as long noncoding RNA (lncRNA) genes. Here we have demonstrated that one such transcript is translated into a 56-amino-acid-long peptide conserved in chordates, corroborating the work published while this manuscript was under review. The Mtln peptide could be detected in mitochondria of mouse cell lines and tissues. In line with its mitochondrial localization, lack of the Mtln decreases the activity of mitochondrial respiratory chain complex I. Unlike the integral components and assembly factors of NADH:ubiquinone oxidoreductase, Mtln does not alter its enzymatic activity directly. Interaction of Mtln with NADH-dependent cytochrome b5 reductase stimulates complex I functioning most likely by providing a favorable lipid composition of the membrane. Study of Mtln illuminates the importance of small peptides, whose genes might frequently be misannotated as lncRNAs, for the control of vitally important cellular processes.
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16
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From the Eukaryotic Molybdenum Cofactor Biosynthesis to the Moonlighting Enzyme mARC. Molecules 2018; 23:molecules23123287. [PMID: 30545001 PMCID: PMC6321594 DOI: 10.3390/molecules23123287] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 11/23/2018] [Accepted: 12/05/2018] [Indexed: 12/20/2022] Open
Abstract
All eukaryotic molybdenum (Mo) enzymes contain in their active site a Mo Cofactor (Moco), which is formed by a tricyclic pyranopterin with a dithiolene chelating the Mo atom. Here, the eukaryotic Moco biosynthetic pathway and the eukaryotic Moco enzymes are overviewed, including nitrate reductase (NR), sulfite oxidase, xanthine oxidoreductase, aldehyde oxidase, and the last one discovered, the moonlighting enzyme mitochondrial Amidoxime Reducing Component (mARC). The mARC enzymes catalyze the reduction of hydroxylated compounds, mostly N-hydroxylated (NHC), but as well of nitrite to nitric oxide, a second messenger. mARC shows a broad spectrum of NHC as substrates, some are prodrugs containing an amidoxime structure, some are mutagens, such as 6-hydroxylaminepurine and some others, which most probably will be discovered soon. Interestingly, all known mARC need the reducing power supplied by different partners. For the NHC reduction, mARC uses cytochrome b5 and cytochrome b5 reductase, however for the nitrite reduction, plant mARC uses NR. Despite the functional importance of mARC enzymatic reactions, the structural mechanism of its Moco-mediated catalysis is starting to be revealed. We propose and compare the mARC catalytic mechanism of nitrite versus NHC reduction. By using the recently resolved structure of a prokaryotic MOSC enzyme, from the mARC protein family, we have modeled an in silico three-dimensional structure of a eukaryotic homologue.
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17
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Li Z, Zhang Y, Zhang Z, Zhao Z, Lv Q. A four‐gene signature predicts the efficacy of paclitaxel‐based neoadjuvant therapy in human epidermal growth factor receptor 2–negative breast cancer. J Cell Biochem 2018; 120:6046-6056. [PMID: 30520096 DOI: 10.1002/jcb.27891] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 09/19/2018] [Indexed: 12/15/2022]
Affiliation(s)
- Zhi Li
- Department of Medical Oncology The First Hospital of China Medical University Shenyang China
- Key Laboratory of Anticancer Drugs and Biotherapy of Liaoning Province The First Hospital of China Medical University Shenyang China
| | - Ye Zhang
- Department of Medical Oncology The First Hospital of China Medical University Shenyang China
- Key Laboratory of Anticancer Drugs and Biotherapy of Liaoning Province The First Hospital of China Medical University Shenyang China
| | - Zhe Zhang
- Department of Pathology Shengjing Hospital of China Medical University Shenyang China
| | - Zhenkun Zhao
- Department of Pathology Shengjing Hospital of China Medical University Shenyang China
| | - Qingjie Lv
- Department of Pathology Shengjing Hospital of China Medical University Shenyang China
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18
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Ginsel C, Plitzko B, Froriep D, Stolfa DA, Jung M, Kubitza C, Scheidig AJ, Havemeyer A, Clement B. The Involvement of the Mitochondrial Amidoxime Reducing Component (mARC) in the Reductive Metabolism of Hydroxamic Acids. Drug Metab Dispos 2018; 46:1396-1402. [DOI: 10.1124/dmd.118.082453] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 07/11/2018] [Indexed: 12/18/2022] Open
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19
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Treyer A, Mateus A, Wiśniewski JR, Boriss H, Matsson P, Artursson P. Intracellular Drug Bioavailability: Effect of Neutral Lipids and Phospholipids. Mol Pharm 2018; 15:2224-2233. [DOI: 10.1021/acs.molpharmaceut.8b00064] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Andrea Treyer
- Department of Pharmacy, Uppsala University, Uppsala 75123, Sweden
| | - André Mateus
- Department of Pharmacy, Uppsala University, Uppsala 75123, Sweden
| | - Jacek R Wiśniewski
- Biochemical Proteomics Group, Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried 82152, Germany
| | | | - Pär Matsson
- Department of Pharmacy, Uppsala University, Uppsala 75123, Sweden
| | - Per Artursson
- Department of Pharmacy, Uppsala University, Uppsala 75123, Sweden
- Science for Life Laboratory Drug Discovery and Development Platform (SciLifelab DDD-P), Uppsala 75123, Sweden
- Uppsala University Drug Optimization and Pharmaceutical Profiling Platform (UDOPP), Uppsala University, Uppsala 75123, Sweden
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20
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Templeman NM, Flibotte S, Chik JHL, Sinha S, Lim GE, Foster LJ, Nislow C, Johnson JD. Reduced Circulating Insulin Enhances Insulin Sensitivity in Old Mice and Extends Lifespan. Cell Rep 2018; 20:451-463. [PMID: 28700945 DOI: 10.1016/j.celrep.2017.06.048] [Citation(s) in RCA: 96] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2016] [Revised: 05/01/2017] [Accepted: 06/19/2017] [Indexed: 12/20/2022] Open
Abstract
The causal relationships between insulin levels, insulin resistance, and longevity are not fully elucidated. Genetic downregulation of insulin/insulin-like growth factor 1 (Igf1) signaling components can extend invertebrate and mammalian lifespan, but insulin resistance, a natural form of decreased insulin signaling, is associated with greater risk of age-related disease in mammals. We compared Ins2+/- mice to Ins2+/+ littermate controls, on a genetically stable Ins1 null background. Proteomic and transcriptomic analyses of livers from 25-week-old mice suggested potential for healthier aging and altered insulin sensitivity in Ins2+/- mice. Halving Ins2 lowered circulating insulin by 25%-34% in aged female mice, without altering Igf1 or circulating Igf1. Remarkably, decreased insulin led to lower fasting glucose and improved insulin sensitivity in aged mice. Moreover, lowered insulin caused significant lifespan extension, observed across two diverse diets. Our study indicates that elevated insulin contributes to age-dependent insulin resistance and that limiting basal insulin levels can extend lifespan.
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Affiliation(s)
- Nicole M Templeman
- Department of Cellular and Physiological Sciences, Diabetes Research Group, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Stephane Flibotte
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Jenny H L Chik
- Department of Biochemistry and Molecular Biology, Michael Smith Laboratories, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Sunita Sinha
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Gareth E Lim
- Department of Cellular and Physiological Sciences, Diabetes Research Group, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Leonard J Foster
- Department of Biochemistry and Molecular Biology, Michael Smith Laboratories, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Corey Nislow
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - James D Johnson
- Department of Cellular and Physiological Sciences, Diabetes Research Group, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada.
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He B, Zhang J, Wang Y, Li Y, Zou X, Liang B. Identification of cytochrome b5 CYTB-5.1 and CYTB-5.2 in C. elegans; evidence for differential regulation of SCD. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1863:235-246. [PMID: 29237573 DOI: 10.1016/j.bbalip.2017.12.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2017] [Revised: 12/02/2017] [Accepted: 12/07/2017] [Indexed: 01/04/2023]
Abstract
Unsaturated fatty acids (UFAs) play crucial roles in living organisms regarding development, energy metabolism, stress resistance, etc. The biosynthesis of UFAs starts from the introduction of the first double bond by stearoyl-CoA desaturase (SCD), converting saturated fatty acids (SFAs) to monounsaturated fatty acids (MUFAs). This desaturation is considered to be an aerobic process that requires cytochrome b5 reductase, cytochrome b5 and SCD. However, this enzyme system remains elusive in Caenorhabditis elegans. Here, we show that inactivation by RNAi knockdown or mutation (gk442189) of putative cytochrome b5 genes cytb-5.1 led to reduced conversion of C18:0 to C18:1(n-9) by SCD desaturases FAT-6/7 in C. elegans. On the contrary, cytb-5.2RNAi and cytb-5.2(gk113588) mutant worms showed decreased conversion of C16:0 to C16:1(n-7) by FAT-5 desaturase. Dietary supplementation with C18:1(n-9) and C18:2(n-6) also showed that CYTB-5.1 is likely required for the activity of FAT-6/7 desaturases, but not for FAT-1 to FAT-4 desaturases. Interestingly, co-immunoprecipitation (Co-IP) demonstrated that either FAT-7 or FAT-5 has ability to interact with both CYTB-5.1 and CYTB-5.2. Moreover, RNAi knockdown of cytb-5.1 upregulates the transcriptional and translational expression of fat-5 to fat-7, which may be due to the feedback induction by reduced C18:1(n-9) and downstream fatty acids. Furthermore, both CYTB-5.1 and CYTB-5.2 are involved in fat accumulation, fertility and lifespan in worms, which may be independent of changes in fatty acid compositions. Collectively, these findings for the first time reveal the differential regulation of various SCDs by distinct cytochrome b5 CYTB-5.1 and CYTB-5.2 in the biosynthesis of UFAs in C. elegans.
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Affiliation(s)
- Baoshen He
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China; Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, Yunnan 650204, China
| | - Jingjing Zhang
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China; Department of Hepatobiliary Surgery, Affiliated Hospital of Guangdong Medical University, Zhanjiang 524001, China
| | - Yanli Wang
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
| | - Yamei Li
- School of Life Sciences, University of Science and Technology of China, Hefei 230036, China
| | - Xiaoju Zou
- Department of Life Science and Biotechnology, Key Laboratory of Special Biological Resource Development and Utilization of University in Yunnan Province, Kunming University, Kunming 650214, China.
| | - Bin Liang
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China; Department of Hepatobiliary Surgery, Affiliated Hospital of Guangdong Medical University, Zhanjiang 524001, China.
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Llamas A, Chamizo-Ampudia A, Tejada-Jimenez M, Galvan A, Fernandez E. The molybdenum cofactor enzyme mARC: Moonlighting or promiscuous enzyme? Biofactors 2017; 43:486-494. [PMID: 28497908 DOI: 10.1002/biof.1362] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 03/20/2017] [Accepted: 03/28/2017] [Indexed: 12/13/2022]
Abstract
Molybdenum (Mo) is present in the active center of eukaryotic enzymes as a tricyclic pyranopterin chelate compound forming the Mo Cofactor (Moco). Four Moco containing enzymes are known in eukaryotes, nitrate reductase (NR), sulfite oxidase (SO), xanthine oxidoreductase (XOR), and aldehyde oxidase (AO). A fifth Moco enzyme has been recently identified. Because of the ability of this enzyme to convert by reduction several amidoximes prodrugs into their active amino forms, it was named mARC (mitochondrial Amidoxime Reducing Component). This enzyme is also able to catalyze the reduction of a broad range of N-hydroxylated compounds (NHC) as the base analogue 6-hydroxylaminopurine (HAP), as well as nitrite to nitric oxide (NO). All the mARC proteins need reducing power that is supplied by other proteins. The human and plants mARC proteins require a Cytochrome b5 (Cytb5) and a Cytochrome b5 reductase (Cytb5-R) to form an electron transfer chain from NADH to the NHC. Recently, plant mARC proteins were shown to be implicated in the reduction of nitrite to NO, and it was proposed that the electrons required for the reaction were supplied by NR instead of Cytochrome b5 components. This newly characterized mARC activity was termed NO Forming Nitrite Reductase (NOFNiR). Moonlighting proteins form a special class of multifunctional enzymes that can perform more than one function; if the extra function is not physiologically relevant, they are called promiscuous enzymes. In this review, we summarize the current knowledge on the mARC protein, and we propose that mARC is a new moonlighting enzyme. © 2017 BioFactors, 43(4):486-494, 2017.
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Affiliation(s)
- Angel Llamas
- Dpto. de Bioquímica y Biología Molecular, Campus de Rabanales y Campus Internacional de Excelencia Agroalimentario (CeiA3), Edif. Severo Ochoa, Universidad de Córdoba, Spain
| | - Alejandro Chamizo-Ampudia
- Dpto. de Bioquímica y Biología Molecular, Campus de Rabanales y Campus Internacional de Excelencia Agroalimentario (CeiA3), Edif. Severo Ochoa, Universidad de Córdoba, Spain
| | - Manuel Tejada-Jimenez
- Dpto. de Bioquímica y Biología Molecular, Campus de Rabanales y Campus Internacional de Excelencia Agroalimentario (CeiA3), Edif. Severo Ochoa, Universidad de Córdoba, Spain
| | - Aurora Galvan
- Dpto. de Bioquímica y Biología Molecular, Campus de Rabanales y Campus Internacional de Excelencia Agroalimentario (CeiA3), Edif. Severo Ochoa, Universidad de Córdoba, Spain
| | - Emilio Fernandez
- Dpto. de Bioquímica y Biología Molecular, Campus de Rabanales y Campus Internacional de Excelencia Agroalimentario (CeiA3), Edif. Severo Ochoa, Universidad de Córdoba, Spain
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Study of Different Variants of Mo Enzyme crARC and the Interaction with Its Partners crCytb5-R and crCytb5-1. Int J Mol Sci 2017; 18:ijms18030670. [PMID: 28335548 PMCID: PMC5372681 DOI: 10.3390/ijms18030670] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 03/07/2017] [Accepted: 03/10/2017] [Indexed: 12/30/2022] Open
Abstract
The mARC (mitochondrial Amidoxime Reducing Component) proteins are recently discovered molybdenum (Mo) Cofactor containing enzymes. They are involved in the reduction of several N-hydroxylated compounds (NHC) and nitrite. Some NHC are prodrugs containing an amidoxime structure or mutagens such as 6-hydroxylaminopurine (HAP). We have studied this protein in the green alga Chlamydomonas reinhardtii (crARC). Interestingly, all the ARC proteins need the reducing power supplied by other proteins. It is known that crARC requires a cytochrome b₅ (crCytb5-1) and a cytochrome b₅ reductase (crCytb5-R) that form an electron transport chain from NADH to the substrates. Here, we have investigated NHC reduction by crARC, the interaction with its partners and the function of important conserved amino acids. Interactions among crARC, crCytb5-1 and crCytb5-R have been studied by size-exclusion chromatography. A protein complex between crARC, crCytb5-1 and crCytb5-R was identified. Twelve conserved crARC amino acids have been substituted by alanine by in vitro mutagenesis. We have determined that the amino acids D182, F210 and R276 are essential for NHC reduction activity, R276 is important and F210 is critical for the Mo Cofactor chelation. Finally, the crARC C-termini were shown to be involved in protein aggregation or oligomerization.
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Tallman KA, Kim HYH, Korade Z, Genaro-Mattos TC, Wages PA, Liu W, Porter NA. Probes for protein adduction in cholesterol biosynthesis disorders: Alkynyl lanosterol as a viable sterol precursor. Redox Biol 2017; 12:182-190. [PMID: 28258022 PMCID: PMC5333532 DOI: 10.1016/j.redox.2017.02.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2017] [Indexed: 01/13/2023] Open
Abstract
The formation of lipid electrophile-protein adducts is associated with many disorders that involve perturbations of cellular redox status. The identities of adducted proteins and the effects of adduction on protein function are mostly unknown and an increased understanding of these factors may help to define the pathogenesis of various human disorders involving oxidative stress. 7-Dehydrocholesterol (7-DHC), the immediate biosynthetic precursor to cholesterol, is highly oxidizable and gives electrophilic oxysterols that adduct proteins readily, a sequence of events proposed to occur in Smith-Lemli-Opitz syndrome (SLOS), a human disorder resulting from an error in cholesterol biosynthesis. Alkynyl lanosterol (a-Lan) was synthesized and studied in Neuro2a cells, Dhcr7-deficient Neuro2a cells and human fibroblasts. When incubated in control Neuro2a cells and control human fibroblasts, a-Lan completed the sequence of steps involved in cholesterol biosynthesis and alkynyl-cholesterol (a-Chol) was the major product formed. In Dhcr7-deficient Neuro2a cells or fibroblasts from SLOS patients, the biosynthetic transformation was interrupted at the penultimate step and alkynyl-7-DHC (a-7-DHC) was the major product formed. When a-Lan was incubated in Dhcr7-deficient Neuro2a cells and the alkynyl tag was used to ligate a biotin group to alkyne-containing products, protein-sterol adducts were isolated and identified. In parallel experiments with a-Lan and a-7-DHC in Dhcr7-deficient Neuro2a cells, a-7-DHC was found to adduct to a larger set of proteins (799) than a-Lan (457) with most of the a-Lan protein adducts (423) being common to the larger a-7-DHC set. Of the 423 proteins found common to both experiments, those formed from a-7-DHC were more highly enriched compared to a DMSO control than were those derived from a-Lan. The 423 common proteins were ranked according to the enrichment determined for each protein in the a-Lan and a-7-DHC experiments and there was a very strong correlation of protein ranks for the adducts formed in the parallel experiments.
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Affiliation(s)
- Keri A Tallman
- Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37235, United States
| | - Hye-Young H Kim
- Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37235, United States
| | - Zeljka Korade
- Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37235, United States; Department of Psychiatry, Vanderbilt University, Nashville, TN 37235, United States
| | - Thiago C Genaro-Mattos
- Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37235, United States
| | - Phillip A Wages
- Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37235, United States
| | - Wei Liu
- Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37235, United States
| | - Ned A Porter
- Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37235, United States; Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37235, United States.
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25
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Plitzko B, Havemeyer A, Bork B, Bittner F, Mendel R, Clement B. Defining the Role of the NADH-Cytochrome-b5 Reductase 3 in the Mitochondrial Amidoxime Reducing Component Enzyme System. ACTA ACUST UNITED AC 2016; 44:1617-21. [PMID: 27469001 DOI: 10.1124/dmd.116.071845] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2016] [Accepted: 07/27/2016] [Indexed: 11/22/2022]
Abstract
The importance of the mitochondrial amidoxime reducing component (mARC)-containing enzyme system in N-reductive metabolism has been studied extensively. It catalyzes the reduction of various N-hydroxylated compounds and therefore acts as the counterpart of cytochrome P450- and flavin-containing monooxygenase-catalyzed oxidations at nitrogen centers. This enzyme system was found to be responsible for the activation of amidoxime and N-hydroxyguanidine prodrugs in drug metabolism. The synergy of three components (mARC, cytochrome b5, and the appropriate reductase) is crucial to exert the N-reductive catalytic effect. Previous studies have demonstrated the involvement of the specific isoforms of the molybdoenzyme mARC and the electron transport protein cytochrome b5 in N-reductive metabolism. To date, the corresponding reductase involved in N-reductive metabolism has yet to be defined because previous investigations have presented ambiguous results. Using small interfering RNA-mediated knockdown in human cells and assessing the stoichiometry of the enzyme system reconstituted in vitro, we provide evidence that NADH-cytochrome-b5 reductase 3 is the principal reductase involved in the mARC enzyme system and is an essential component of N-reductive metabolism in human cells. In addition, only minimal levels of cytochrome-b5 reductase 3 protein are sufficient for catalysis, which impeded previous attempts to identify the reductase.
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Affiliation(s)
- Birte Plitzko
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts University of Kiel, Kiel, Germany (B.P., A.H., B.C.); and Department of Plant Biology, Braunschweig University of Technology, Braunschweig, Germany (B.B., F.B., R.M.)
| | - Antje Havemeyer
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts University of Kiel, Kiel, Germany (B.P., A.H., B.C.); and Department of Plant Biology, Braunschweig University of Technology, Braunschweig, Germany (B.B., F.B., R.M.)
| | - Bettina Bork
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts University of Kiel, Kiel, Germany (B.P., A.H., B.C.); and Department of Plant Biology, Braunschweig University of Technology, Braunschweig, Germany (B.B., F.B., R.M.)
| | - Florian Bittner
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts University of Kiel, Kiel, Germany (B.P., A.H., B.C.); and Department of Plant Biology, Braunschweig University of Technology, Braunschweig, Germany (B.B., F.B., R.M.)
| | - Ralf Mendel
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts University of Kiel, Kiel, Germany (B.P., A.H., B.C.); and Department of Plant Biology, Braunschweig University of Technology, Braunschweig, Germany (B.B., F.B., R.M.)
| | - Bernd Clement
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts University of Kiel, Kiel, Germany (B.P., A.H., B.C.); and Department of Plant Biology, Braunschweig University of Technology, Braunschweig, Germany (B.B., F.B., R.M.)
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26
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Pacheco-Marín R, Melendez-Zajgla J, Castillo-Rojas G, Mandujano-Tinoco E, Garcia-Venzor A, Uribe-Carvajal S, Cabrera-Orefice A, Gonzalez-Torres C, Gaytan-Cervantes J, Mitre-Aguilar IB, Maldonado V. Transcriptome profile of the early stages of breast cancer tumoral spheroids. Sci Rep 2016; 6:23373. [PMID: 27021602 PMCID: PMC4810430 DOI: 10.1038/srep23373] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 03/02/2016] [Indexed: 12/15/2022] Open
Abstract
Oxygen or nutrient deprivation of early stage tumoral spheroids can be used to reliably mimic the initial growth of primary and metastatic cancer cells. However, cancer cell growth during the initial stages has not been fully explored using a genome-wide approach. Thus, in the present study, we investigated the transcriptome of breast cancer cells during the initial stages of tumoral growth using RNAseq in a model of Multicellular Tumor Spheroids (MTS). Network analyses showed that a metastatic signature was enriched as several adhesion molecules were deregulated, including EPCAM, E-cadherin, integrins and syndecans, which were further supported by an increase in cell migration. Interestingly, we also found that the cancer cells at this stage of growth exhibited a paradoxical hyperactivation of oxidative mitochondrial metabolism. In addition, we found a large number of regulated (long non coding RNA) lncRNAs, several of which were co-regulated with neighboring genes. The regulatory role of some of these lncRNAs on mRNA expression was demonstrated with gain of function assays. This is the first report of an early-stage MTS transcriptome, which not only reveals a complex expression landscape, but points toward an important contribution of long non-coding RNAs in the final phenotype of three-dimensional cellular models.
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Affiliation(s)
- Rosario Pacheco-Marín
- Epigenetics, National Institute of Genomic Medicine, Periférico Sur No. 4809, Col Arenal Tepepan, Delegación Tlalpan, México, D.F., C.P 14610.,Posgraduate Program in Biological Sciences, Faculty of Medicine (UNAM), University City Avenue 3000 C.P. 04510, Coyoacan, Mexico City
| | - Jorge Melendez-Zajgla
- Functional Genomics laboratories, National Institute of Genomic Medicine, Periférico Sur No. 4809, Col Arenal Tepepan, Delegación Tlalpan, México, D.F., C.P 14610
| | - Gonzalo Castillo-Rojas
- Microbial Molecular Immunology Program, Department of Microbiology and Parasitology, Faculty of Medicine, National Autonomous University of Mexico (UNAM), University City Avenue 3000 C.P. 04510, Coyoacan, Mexico City
| | - Edna Mandujano-Tinoco
- Functional Genomics laboratories, National Institute of Genomic Medicine, Periférico Sur No. 4809, Col Arenal Tepepan, Delegación Tlalpan, México, D.F., C.P 14610
| | - Alfredo Garcia-Venzor
- Functional Genomics laboratories, National Institute of Genomic Medicine, Periférico Sur No. 4809, Col Arenal Tepepan, Delegación Tlalpan, México, D.F., C.P 14610
| | - Salvador Uribe-Carvajal
- Department of Molecular Genetics, Institute of Cellular Physiology (UNAM), University City Avenue 3000 C.P. 04510, Coyoacan, Mexico City
| | - Alfredo Cabrera-Orefice
- Department of Molecular Genetics, Institute of Cellular Physiology (UNAM), University City Avenue 3000 C.P. 04510, Coyoacan, Mexico City
| | - Carolina Gonzalez-Torres
- Functional Genomics laboratories, National Institute of Genomic Medicine, Periférico Sur No. 4809, Col Arenal Tepepan, Delegación Tlalpan, México, D.F., C.P 14610
| | - Javier Gaytan-Cervantes
- Functional Genomics laboratories, National Institute of Genomic Medicine, Periférico Sur No. 4809, Col Arenal Tepepan, Delegación Tlalpan, México, D.F., C.P 14610
| | - Irma B Mitre-Aguilar
- Unit of Biochemistry, National Institute of Medical Sciences and Nutrition Salvador Zubirán (INCMNSZ), Av. Vasco de Quiroga N° 15, Colonia Belisario Domínguez Sección XVI, Delegación Tlalpan. CP.14080, México D. F., México
| | - Vilma Maldonado
- Epigenetics, National Institute of Genomic Medicine, Periférico Sur No. 4809, Col Arenal Tepepan, Delegación Tlalpan, México, D.F., C.P 14610
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27
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Ma Y, Gao J, Yin J, Gu L, Liu X, Chen S, Huang Q, Lu H, Yang Y, Zhou H, Wang Y, Peng Y. Identification of a Novel Function of Adipocyte Plasma Membrane-Associated Protein (APMAP) in Gestational Diabetes Mellitus by Proteomic Analysis of Omental Adipose Tissue. J Proteome Res 2016; 15:628-37. [PMID: 26767403 DOI: 10.1021/acs.jproteome.5b01030] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Gestational diabetes mellitus (GDM) is considered as an early stage of type 2 diabetes mellitus. In this study, we compared demographic and clinical data between six GDM subjects and six normal glucose tolerance (NGT; healthy controls) subjects and found that homeostasis model of assessment for insulin resistance index (HOMA-IR) increased in GDM. Many previous studies demonstrated that omental adipose tissue dysfunction could induce insulin resistance. Thus, to investigate the cause of insulin resistance in GDM, we used label-free proteomics to identify differentially expressed proteins in omental adipose tissues from GDM and NGT subjects (data are available via ProteomeXchange with identifier PXD003095). A total of 3528 proteins were identified, including 66 significantly changed proteins. Adipocyte plasma membrane-associated protein (APMAP, a.k.a. C20orf3), one of the differentially expressed proteins, was down-regulated in GDM omental adipose tissues. Furthermore, mature 3T3-L1 adipocytes were used to simulate omental adipocytes. The inhibition of APMAP expression by RNAi impaired insulin signaling and activated NFκB signaling in these adipocytes. Our study revealed that the down-regulation of APMAP in omental adipose tissue may play an important role in insulin resistance in the pathophysiology of GDM.
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Affiliation(s)
| | - Jing Gao
- Department of Analytical Chemistry and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences , 555 Zuchongzhi Road, Shanghai 201203, China
| | | | | | - Xing Liu
- Department of Analytical Chemistry and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences , 555 Zuchongzhi Road, Shanghai 201203, China
| | | | | | | | | | - Hu Zhou
- Department of Analytical Chemistry and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences , 555 Zuchongzhi Road, Shanghai 201203, China
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28
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Li J, Papadopoulos V, Vihma V. Steroid biosynthesis in adipose tissue. Steroids 2015; 103:89-104. [PMID: 25846979 DOI: 10.1016/j.steroids.2015.03.016] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 03/20/2015] [Accepted: 03/24/2015] [Indexed: 12/25/2022]
Abstract
Tissue-specific expression of steroidogenic enzymes allows the modulation of active steroid levels in a local manner. Thus, the measurement of local steroid concentrations, rather than the circulating levels, has been recognized as a more accurate indicator of the steroid action within a specific tissue. Adipose tissue, one of the largest endocrine tissues in the human body, has been established as an important site for steroid storage and metabolism. Locally produced steroids, through the enzymatic conversion from steroid precursors delivered to adipose tissue, have been proven to either functionally regulate adipose tissue metabolism, or quantitatively contribute to the whole body's steroid levels. Most recently, it has been suggested that adipose tissue may contain the steroidogenic machinery necessary for the initiation of steroid biosynthesis de novo from cholesterol. This review summarizes the evidence indicating the presence of the entire steroidogenic apparatus in adipose tissue and discusses the potential roles of local steroid products in modulating adipose tissue activity and other metabolic parameters.
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Affiliation(s)
- Jiehan Li
- Research Institute of the McGill University Health Centre, McGill University, Montreal, Canada; Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada; Department of Medicine, McGill University, Montreal, Canada; Department of Biochemistry, McGill University, Montreal, Canada
| | - Vassilios Papadopoulos
- Research Institute of the McGill University Health Centre, McGill University, Montreal, Canada; Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada; Department of Medicine, McGill University, Montreal, Canada; Department of Biochemistry, McGill University, Montreal, Canada.
| | - Veera Vihma
- Folkhälsan Research Center, Helsinki, Finland; University of Helsinki and Helsinki University Central Hospital, Heart and Lung Center, Helsinki, Finland.
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29
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Neve EPA, Köfeler H, Hendriks DFG, Nordling Å, Gogvadze V, Mkrtchian S, Näslund E, Ingelman-Sundberg M. Expression and Function of mARC: Roles in Lipogenesis and Metabolic Activation of Ximelagatran. PLoS One 2015; 10:e0138487. [PMID: 26378779 PMCID: PMC4574727 DOI: 10.1371/journal.pone.0138487] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 08/30/2015] [Indexed: 12/17/2022] Open
Abstract
Recently two novel enzymes were identified in the outer mitochondrial membrane, mARC1 and mARC2. These molybdenum containing enzymes can reduce a variety of N-hydroxylated compounds, such as N-hydroxy-guanidines and sulfohydroxamic acids, as well as convert nitrite into nitric oxide (NO). However, their endogenous functions remain unknown. Here we demonstrate a specific developmental pattern of expression of these enzymes. mARC1, but not mARC2, was found to be expressed in fetal human liver, whereas both, in particular mARC2, are abundant in adult liver and also expressed in omental and subcutaneous fat. Caloric diet restriction of obese patients caused a decreased expression of mARC2 in liver, similar to that seen in the livers of starved rats. Knock down of mARC2 expression by siRNA in murine adipocytes had statistically significant effect on the level of diglycerides and on the fatty acid composition of some triglycerides, concomitantly a clear trend toward the reduced formation of most of triglyceride and phospholipid species was observed. The involvement of mARC2 in the metabolism of the hepatotoxic drug ximelagatran was evaluated in hepatocytes and adipocytes. Ximelagatran was shown to cause oxidative stress and knock down of mARC2 in adipocytes prevented ximelagatran induced inhibition of mitochondrial respiration. In conclusion, our data indicate that mARC1 and mARC2 have different developmental expression profiles, and that mARC2 is involved in lipogenesis, is regulated by nutritional status and responsible for activation of ximelagatran into a mitotoxic metabolite(s).
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Affiliation(s)
- Etienne P. A. Neve
- Section of Pharmacogenetics, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Harald Köfeler
- Medical University Graz, Center for Medical Research (ZMF), Graz, Austria
| | - Delilah F. G. Hendriks
- Section of Pharmacogenetics, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Åsa Nordling
- Section of Pharmacogenetics, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Vladimir Gogvadze
- Institute of Environmental Medicine, Section of Toxicology, Stockholm, Sweden
| | - Souren Mkrtchian
- Section of Pharmacogenetics, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Erik Näslund
- Department of Clinical Sciences, Danderyd Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Magnus Ingelman-Sundberg
- Section of Pharmacogenetics, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
- * E-mail:
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30
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Porter TD. Electron Transfer Pathways in Cholesterol Synthesis. Lipids 2015; 50:927-36. [PMID: 26344922 DOI: 10.1007/s11745-015-4065-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 08/21/2015] [Indexed: 12/17/2022]
Abstract
Cholesterol synthesis in the endoplasmic reticulum requires electron input at multiple steps and utilizes both NADH and NADPH as the electron source. Four enzymes catalyzing five steps in the pathway require electron input: squalene monooxygenase, lanosterol demethylase, sterol 4α-methyl oxidase, and sterol C5-desaturase. The electron-donor proteins for these enzymes include cytochrome P450 reductase and the cytochrome b5 pathway. Here I review the evidence for electron donor protein requirements with these enzymes, the evidence for additional electron donor pathways, and the effect of deletion of these redox enzymes on cholesterol and lipid metabolism.
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Affiliation(s)
- Todd D Porter
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY, 40536-0596, USA.
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Derbyshire MC, Michaelson L, Parker J, Kelly S, Thacker U, Powers SJ, Bailey A, Hammond-Kosack K, Courbot M, Rudd J. Analysis of cytochrome b(5) reductase-mediated metabolism in the phytopathogenic fungus Zymoseptoria tritici reveals novel functionalities implicated in virulence. Fungal Genet Biol 2015; 82:69-84. [PMID: 26074495 PMCID: PMC4557397 DOI: 10.1016/j.fgb.2015.05.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Revised: 05/19/2015] [Accepted: 05/20/2015] [Indexed: 12/15/2022]
Abstract
Septoria tritici blotch (STB) caused by the Ascomycete fungus Zymoseptoria tritici is one of the most economically damaging diseases of wheat worldwide. Z. tritici is currently a major target for agricultural fungicides, especially in temperate regions where it is most prevalent. Many fungicides target electron transfer enzymes because these are often important for cell function. Therefore characterisation of genes encoding such enzymes may be important for the development of novel disease intervention strategies. Microsomal cytochrome b5 reductases (CBRs) are an important family of electron transfer proteins which in eukaryotes are involved in the biosynthesis of fatty acids and complex lipids including sphingolipids and sterols. Unlike the model yeast Saccharomyces cerevisiae which possesses only one microsomal CBR, the fully sequenced genome of Z. tritici bears three possible microsomal CBRs. RNA sequencing analysis revealed that ZtCBR1 is the most highly expressed of these genes under all in vitro and in planta conditions tested, therefore ΔZtCBR1 mutant strains were generated through targeted gene disruption. These strains exhibited delayed disease symptoms on wheat leaves and severely limited asexual sporulation. ΔZtCBR1 strains also exhibited aberrant spore morphology and hyphal growth in vitro. These defects coincided with alterations in fatty acid, sphingolipid and sterol biosynthesis observed through GC-MS and HPLC analyses. Data is presented which suggests that Z. tritici may use ZtCBR1 as an additional electron donor for key steps in ergosterol biosynthesis, one of which is targeted by azole fungicides. Our study reports the first functional characterisation of CBR gene family members in a plant pathogenic filamentous fungus. This also represents the first direct observation of CBR functional ablation impacting upon fungal sterol biosynthesis.
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Affiliation(s)
- Mark C Derbyshire
- Department of Plant Biology and Crop Science, Rothamsted Research, West Common, Harpenden, Hertfordshire AL5 2JQ, UK.
| | - Louise Michaelson
- Department of Biological Chemistry and Crop Protection, Rothamsted Research, West Common, Harpenden, Hertfordshire AL5 2JQ, UK
| | - Josie Parker
- Centre for Cytochrome P450 Diversity, Institute of Life Science, College of Medicine, Swansea University Singleton Park, Swansea SA2 8PP, Wales, UK
| | - Steven Kelly
- Centre for Cytochrome P450 Diversity, Institute of Life Science, College of Medicine, Swansea University Singleton Park, Swansea SA2 8PP, Wales, UK
| | | | - Stephen J Powers
- Department of Computational and Systems Biology, Rothamsted Research, West Common, Harpenden, Hertfordshire AL5 2JQ, UK
| | - Andy Bailey
- Bristol University, Senate House, Tyndall Avenue, Bristol BS8 1TH, UK
| | - Kim Hammond-Kosack
- Department of Plant Biology and Crop Science, Rothamsted Research, West Common, Harpenden, Hertfordshire AL5 2JQ, UK
| | - Mikael Courbot
- Syngenta, Syngenta AG, Schaffhauserstrasse, CH-4332 Stein, Switzerland
| | - Jason Rudd
- Department of Plant Biology and Crop Science, Rothamsted Research, West Common, Harpenden, Hertfordshire AL5 2JQ, UK.
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32
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Plitzko B, Havemeyer A, Kunze T, Clement B. The pivotal role of the mitochondrial amidoxime reducing component 2 in protecting human cells against apoptotic effects of the base analog N6-hydroxylaminopurine. J Biol Chem 2015; 290:10126-35. [PMID: 25713076 DOI: 10.1074/jbc.m115.640052] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Indexed: 12/27/2022] Open
Abstract
N-Hydroxylated nucleobases and nucleosides as N-hydroxylaminopurine (HAP) or N-hydroxyadenosine (HAPR) may be generated endogenously in the course of cell metabolism by cytochrome P450, by oxidative stress or by a deviating nucleotide biosynthesis. These compounds have shown to be toxic and mutagenic for procaryotic and eucaryotic cells. For DNA replication fidelity it is therefore of great importance that organisms exhibit effective mechanisms to remove such non-canonical base analogs from DNA precursor pools. In vitro, the molybdoenzymes mitochondrial amidoxime reducing component 1 and 2 (mARC1 and mARC2) have shown to be capable of reducing N-hydroxylated base analogs and nucleoside analogs to the corresponding canonical nucleobases and nucleosides upon reconstitution with the electron transport proteins cytochrome b5 and NADH-cytochrome b5 reductase. By RNAi-mediated down-regulation of mARC in human cell lines the mARC-dependent N-reductive detoxication of HAP in cell metabolism could be demonstrated. For HAPR, on the other hand, the reduction to adenosine seems to be of less significance in the detoxication pathway of human cells as HAPR is primarily metabolized to inosine by direct dehydroxylamination catalyzed by adenosine deaminase. Furthermore, the effect of mARC knockdown on sensitivity of human cells to HAP was examined by flow cytometric quantification of apoptotic cell death and detection of poly (ADP-ribose) polymerase (PARP) cleavage. mARC2 was shown to protect HeLa cells against the apoptotic effects of the base analog, whereas the involvement of mARC1 in reductive detoxication of HAP does not seem to be pivotal.
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Affiliation(s)
- Birte Plitzko
- From the Department of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Christian-Albrechts-University of Kiel, 24118 Kiel, Germany
| | - Antje Havemeyer
- From the Department of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Christian-Albrechts-University of Kiel, 24118 Kiel, Germany
| | - Thomas Kunze
- From the Department of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Christian-Albrechts-University of Kiel, 24118 Kiel, Germany
| | - Bernd Clement
- From the Department of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Christian-Albrechts-University of Kiel, 24118 Kiel, Germany
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Nitrite reduction by molybdoenzymes: a new class of nitric oxide-forming nitrite reductases. J Biol Inorg Chem 2015; 20:403-33. [DOI: 10.1007/s00775-014-1234-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 12/14/2014] [Indexed: 02/07/2023]
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Bauch E, Reichmann D, Mendel RR, Bittner F, Manke AM, Kurz P, Girreser U, Havemeyer A, Clement B. Electrochemical and mARC-catalyzed enzymatic reduction of para-substituted benzamidoximes: consequences for the prodrug concept "amidoximes instead of amidines". ChemMedChem 2014; 10:360-7. [PMID: 25512261 DOI: 10.1002/cmdc.201402437] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Indexed: 11/05/2022]
Abstract
The mitochondrial amidoxime reducing component (mARC) activates amidoxime prodrugs by reduction to the corresponding amidine drugs. This study analyzes relationships between the chemical structure of the prodrug and its metabolic activation and compares its enzyme-mediated vs. electrochemical reduction. The enzyme kinetic parameters KM and Vmax for the N-reduction of ten para-substituted derivatives of the model compound benzamidoxime were determined by incubation with recombinant proteins and subcellular fractions from pig liver followed by quantification of the metabolites by HPLC. A clear influence of the substituents at position 4 on the chemical properties of the amidoxime function was confirmed by correlation analyses of (1) H NMR chemical shifts and the redox potentials of the 4-substituted benzamidoximes with Hammett's σ. However, no clear relationship between the kinetic parameters for the enzymatic reduction and Hammett's σ or the lipophilicity could be found. It is thus concluded that these properties as well as the redox potential of the amidoxime can be largely ignored during the development of new amidoxime prodrugs, at least regarding prodrug activation.
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Affiliation(s)
- Eva Bauch
- Department of Pharmaceutical and Medicinal Chemistry, Christian Albrechts University Kiel, Gutenbergstraße 76, 24118 Kiel (Germany)
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35
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The mammalian molybdenum enzymes of mARC. J Biol Inorg Chem 2014; 20:265-75. [PMID: 25425164 DOI: 10.1007/s00775-014-1216-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Accepted: 11/11/2014] [Indexed: 01/14/2023]
Abstract
The "mitochondrial amidoxime reducing component" (mARC) is the most recently discovered molybdenum-containing enzyme in mammals. All mammalian genomes studied to date contain two mARC genes: MARC1 and MARC2. The proteins encoded by these genes are mARC-1 and mARC-2 and represent the simplest form of eukaryotic molybdenum enzymes, only binding the molybdenum cofactor. In the presence of NADH, mARC proteins exert N-reductive activity together with the two electron transport proteins cytochrome b5 type B and NADH cytochrome b5 reductase. This enzyme system is capable of reducing a great variety of N-hydroxylated substrates. It plays a decisive role in the activation of prodrugs containing an amidoxime structure, and in detoxification pathways, e.g., of N-hydroxylated purine and pyrimidine bases. It belongs to a group of drug metabolism enzymes, in particular as a counterpart of P450 formed N-oxygenated metabolites. Its physiological relevance, on the other hand, is largely unknown. The aim of this article is to summarize our current knowledge of these proteins with a special focus on the mammalian enzymes and their N-reductive activity.
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Ott G, Plitzko B, Krischkowski C, Reichmann D, Bittner F, Mendel RR, Kunze T, Clement B, Havemeyer A. Reduction of Sulfamethoxazole Hydroxylamine (SMX-HA) by the Mitochondrial Amidoxime Reducing Component (mARC). Chem Res Toxicol 2014; 27:1687-95. [DOI: 10.1021/tx500174u] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Gudrun Ott
- Department
of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Christian-Albrechts-University of Kiel, Gutenbergstrasse 76, D-24118 Kiel, Germany
| | - Birte Plitzko
- Department
of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Christian-Albrechts-University of Kiel, Gutenbergstrasse 76, D-24118 Kiel, Germany
| | - Carmen Krischkowski
- Department
of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Christian-Albrechts-University of Kiel, Gutenbergstrasse 76, D-24118 Kiel, Germany
| | - Debora Reichmann
- Department
of Plant Biology, Braunschweig University of Technology, Humboldtstrasse
1, D-38106 Braunschweig, Germany
| | - Florian Bittner
- Department
of Plant Biology, Braunschweig University of Technology, Humboldtstrasse
1, D-38106 Braunschweig, Germany
| | - Ralf R. Mendel
- Department
of Plant Biology, Braunschweig University of Technology, Humboldtstrasse
1, D-38106 Braunschweig, Germany
| | - Thomas Kunze
- Department
of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Christian-Albrechts-University of Kiel, Gutenbergstrasse 76, D-24118 Kiel, Germany
| | - Bernd Clement
- Department
of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Christian-Albrechts-University of Kiel, Gutenbergstrasse 76, D-24118 Kiel, Germany
| | - Antje Havemeyer
- Department
of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Christian-Albrechts-University of Kiel, Gutenbergstrasse 76, D-24118 Kiel, Germany
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Nikiforova AB, Saris NEL, Kruglov AG. External mitochondrial NADH-dependent reductase of redox cyclers: VDAC1 or Cyb5R3? Free Radic Biol Med 2014; 74:74-84. [PMID: 24945955 DOI: 10.1016/j.freeradbiomed.2014.06.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Revised: 06/06/2014] [Accepted: 06/10/2014] [Indexed: 11/19/2022]
Abstract
It was reported that VDAC1 possesses an NADH oxidoreductase activity and plays an important role in the activation of xenobiotics in the outer mitochondrial membrane. In the present work, we evaluated the participation of VDAC1 and Cyb5R3 in the NADH-dependent activation of various redox cyclers in mitochondria. We show that external NADH oxidoreductase caused the redox cycling of menadione ≫ lucigenin>nitrofurantoin. Paraquat was predominantly activated by internal mitochondria oxidoreductases. An increase in the ionic strength stimulated and suppressed the redox cycling of negatively and positively charged acceptors, as was expected for the Cyb5R3-mediated reduction. Antibodies against Cyb5R3 but not VDAC substantially inhibited the NADH-related oxidoreductase activities. The specific VDAC blockers G3139 and erastin, separately or in combination, in concentrations sufficient for the inhibition of substrate transport, exhibited minimal effects on the redox cycler-dependent NADH oxidation, ROS generation, and reduction of exogenous cytochrome c. In contrast, Cyb5R3 inhibitors (6-propyl-2-thiouracil, p-chloromercuriobenzoate, quercetin, mersalyl, and ebselen) showed similar patterns of inhibition of ROS generation and cytochrome c reduction. The analysis of the spectra of the endogenous cytochromes b5 and c in the presence of nitrofurantoin and the inhibitors of VDAC and Cyb5R3 demonstrated that the redox cycler can transfer electrons from Cyb5R3 to endogenous cytochrome c. This caused the oxidation of outer membrane-bound cytochrome b5, which is in redox balance with Cyb5R3. The data obtained argue against VDAC1 and in favor of Cyb5R3 involvement in the activation of redox cyclers in the outer mitochondrial membrane.
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Affiliation(s)
- Anna B Nikiforova
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russia
| | - Nils-Erik L Saris
- Department of Food and Environmental Sciences, University of Helsinki, FIN-00014 Helsinki, Finland
| | - Alexey G Kruglov
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russia.
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Jakobs HH, Mikula M, Havemeyer A, Strzalkowska A, Borowa-Chmielak M, Dzwonek A, Gajewska M, Hennig EE, Ostrowski J, Clement B. The N-reductive system composed of mitochondrial amidoxime reducing component (mARC), cytochrome b5 (CYB5B) and cytochrome b5 reductase (CYB5R) is regulated by fasting and high fat diet in mice. PLoS One 2014; 9:e105371. [PMID: 25144769 PMCID: PMC4140751 DOI: 10.1371/journal.pone.0105371] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 07/21/2014] [Indexed: 12/11/2022] Open
Abstract
The mitochondrial amidoxime reducing component mARC is the fourth mammalian molybdenum enzyme. The protein is capable of reducing N-oxygenated structures, but requires cytochrome b5 and cytochrome b5 reductase for electron transfer to catalyze such reactions. It is well accepted that the enzyme is involved in N-reductive drug metabolism such as the activation of amidoxime prodrugs. However, the endogenous function of the protein is not fully understood. Among other functions, an involvement in lipogenesis is discussed. To study the potential involvement of the protein in energy metabolism, we tested whether the mARC protein and its partners are regulated due to fasting and high fat diet in mice. We used qRT-PCR for expression studies, Western Blot analysis to study protein levels and an N-reductive biotransformation assay to gain activity data. Indeed all proteins of the N-reductive system are regulated by fasting and its activity decreases. To study the potential impact of these changes on prodrug activation in vivo, another mice experiment was conducted. Model compound benzamidoxime was injected to mice that underwent fasting and the resulting metabolite of the N-reductive reaction, benzamidine, was determined. Albeit altered in vitro activity, no changes in the metabolite concentration in vivo were detectable and we can dispel concerns that fasting alters prodrug activation in animal models. With respect to high fat diet, changes in the mARC proteins occur that result in increased N-reductive activity. With this study we provide further evidence that the endogenous function of the mARC protein is linked with lipid metabolism.
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Affiliation(s)
- Heyka H. Jakobs
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Michal Mikula
- Department of Genetics, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Warsaw, Poland
| | - Antje Havemeyer
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Adriana Strzalkowska
- Department of Genetics, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Warsaw, Poland
| | - Monika Borowa-Chmielak
- Department of Genetics, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Warsaw, Poland
| | - Artur Dzwonek
- Department of Genetics, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Warsaw, Poland
| | - Marta Gajewska
- Department of Genetics, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Warsaw, Poland
| | - Ewa E. Hennig
- Department of Genetics, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Warsaw, Poland
- Department of Gastroenterology and Hepatology, Medical Center for Postgraduate Education, Warsaw, Poland
| | - Jerzy Ostrowski
- Department of Genetics, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Warsaw, Poland
- Department of Gastroenterology and Hepatology, Medical Center for Postgraduate Education, Warsaw, Poland
| | - Bernd Clement
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
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Jakobs HH, Froriep D, Havemeyer A, Mendel RR, Bittner F, Clement B. The Mitochondrial Amidoxime Reducing Component (mARC): Involvement in Metabolic Reduction ofN-Oxides, Oximes andN-Hydroxyamidinohydrazones. ChemMedChem 2014; 9:2381-7. [DOI: 10.1002/cmdc.201402127] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Indexed: 11/12/2022]
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40
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Ott G, Reichmann D, Boerger C, Cascorbi I, Bittner F, Mendel RR, Kunze T, Clement B, Havemeyer A. Functional characterization of protein variants encoded by nonsynonymous single nucleotide polymorphisms in MARC1 and MARC2 in healthy Caucasians. Drug Metab Dispos 2014; 42:718-25. [PMID: 24423752 DOI: 10.1124/dmd.113.055202] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Human molybdenum-containing enzyme mitochondrial amidoxime reducing component (mARC), cytochrome b5 type B, and NADH cytochrome b5 reductase form an N-reductive enzyme system that is capable of reducing N-hydroxylated compounds. Genetic variations are known, but their functional relevance is unclear. Our study aimed to investigate the incidence of nonsynonymous single nucleotide polymorphisms (SNPs) in the mARC genes in healthy Caucasian volunteers, to determine saturation of the protein variants with molybdenum cofactor (Moco), and to characterize the kinetic behavior of the protein variants by in vitro biotransformation studies. Genotype frequencies of six SNPs in the mARC genes (c.493A>G, c.560T>A, c.736T>A, and c.739G>C in MARC1; c.730G>A and c.735T>G in MARC2) were determined by pyrosequencing in a cohort of 340 healthy Caucasians. Protein variants were expressed in Escherichia coli. Saturation with Moco was determined by measurement of molybdenum by inductively coupled mass spectrometry. Steady state assays were performed with benzamidoxime. The six variants were of low frequency in this Caucasian population. Only one homozygous variant (c.493A; MARC1) was detected. All protein variants were able to bind Moco. Steady state assays showed statistically significant decreases of catalytic efficiency values for the mARC-2 wild type compared with the mARC-1 wild type (P < 0.05) and for two mARC-2 variants compared with the mARC-2 wild type (G244S, P < 0.05; C245W, P < 0.05). After simultaneous substitution of more than two amino acids in the mARC-1 protein, N-reductive activity was decreased 5-fold. One homozygous variant of MARC1 was detected in our sample. The encoded protein variant (A165T) showed no different kinetic parameters in the N-reduction of benzamidoxime.
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Affiliation(s)
- Gudrun Ott
- Department of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Christian-Albrechts-University of Kiel, Kiel, Germany (G.O., T.K., B.C., A.H.); Department of Plant Biology, Technical University of Braunschweig, Braunschweig, Germany (D.R., F.B., R.-R.M.); and Institute of Experimental and Clinical Pharmacology, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany (C.B., I.C.)
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41
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Matsson EM, Eriksson UG, Palm JE, Artursson P, Karlgren M, Lazorova L, Brännström M, Ekdahl A, Dunér K, Knutson L, Johansson S, Schützer KM, Lennernäs H. Combined in vitro-in vivo approach to assess the hepatobiliary disposition of a novel oral thrombin inhibitor. Mol Pharm 2013; 10:4252-62. [PMID: 24079718 DOI: 10.1021/mp400341t] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Two clinical trials and a large set of in vitro transporter experiments were performed to investigate if the hepatobiliary disposition of the direct thrombin inhibitor prodrug AZD0837 is the mechanism for the drug-drug interaction with ketoconazole observed in a previous clinical study. In Study 1, [(3)H]AZD0837 was administered to healthy male volunteers (n = 8) to quantify and identify the metabolites excreted in bile. Bile was sampled directly from the jejunum by duodenal aspiration via an oro-enteric tube. In Study 2, the effect of ketoconazole on the plasma and bile pharmacokinetics of AZD0837, the intermediate metabolite (AR-H069927), and the active form (AR-H067637) was investigated (n = 17). Co-administration with ketoconazole elevated the plasma exposure to AZD0837 and the active form approximately 2-fold compared to placebo, which may be explained by inhibited CYP3A4 metabolism and reduced biliary clearance, respectively. High concentrations of the active form was measured in bile with a bile-to-plasma AUC ratio of approximately 75, indicating involvement of transporter-mediated excretion of the compound. AZD0837 and its metabolites were further investigated as substrates of hepatic uptake and efflux transporters in vitro. Studies in MDCK-MDR1 cell monolayers and P-glycoprotein (P-gp) expressing membrane vesicles identified AZD0837, the intermediate, and the active form as substrates of P-gp. The active form was also identified as a substrate of the multidrug and toxin extrusion 1 (MATE1) transporter and the organic cation transporter 1 (OCT1), in HEK cells transfected with the respective transporter. Ketoconazole was shown to inhibit all of these three transporters; in particular, inhibition of P-gp and MATE1 occurred in a clinically relevant concentration range. In conclusion, the hepatobiliary transport pathways of AZD0837 and its metabolites were identified in vitro and in vivo. Inhibition of the canalicular transporters P-gp and MATE1 may lead to enhanced plasma exposure to the active form, which could, at least in part, explain the clinical interaction with ketoconazole.
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Affiliation(s)
- Elin M Matsson
- Department of Pharmacy, Uppsala University , Box 580, SE-751 23 Uppsala, Sweden
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Kozmin SG, Stepchenkova EI, Schaaper RM. TusA (YhhP) and IscS are required for molybdenum cofactor-dependent base-analog detoxification. Microbiologyopen 2013; 2:743-55. [PMID: 23894086 PMCID: PMC3831636 DOI: 10.1002/mbo3.108] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Revised: 05/30/2013] [Accepted: 06/07/2013] [Indexed: 12/15/2022] Open
Abstract
Lack of molybdenum cofactor (Moco) in Escherichia coli leads to hypersensitivity to the mutagenic and toxic effects of N-hydroxylated base analogs, such as 6-N-hydroxylaminopurine (HAP). This phenotype is due to the loss of two Moco-dependent activities, YcbX and YiiM, that are capable of reducing HAP to adenine. Here, we describe two novel HAP-sensitive mutants containing a defect in iscS or tusA (yhhP) gene. IscS is a major L-cysteine desulfurase involved in iron-sulfur cluster synthesis, thiamine synthesis, and tRNA thiomodification. TusA is a small sulfur-carrier protein that interacts with IscS. We show that both IscS and TusA operate within the Moco-dependent pathway. Like other Moco-deficient strains, tusA and iscS mutants are HAP sensitive and resistant to chlorate under anaerobic conditions. The base-analog sensitivity of iscS or tusA strains could be suppressed by supplying exogenous L-cysteine or sulfide or by an increase in endogenous sulfur donors (cysB constitutive mutant). The data suggest that iscS and tusA mutants have a defect in the mobilization of sulfur required for active YcbX/YiiM proteins as well as nitrate reductase, presumably due to lack of functional Moco. Overall, our data imply a novel and indispensable role of the IscS/TusA complex in the activity of several molybdoenzymes.
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Affiliation(s)
- Stanislav G Kozmin
- Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, 27709
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43
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Plitzko B, Ott G, Reichmann D, Henderson CJ, Wolf CR, Mendel R, Bittner F, Clement B, Havemeyer A. The involvement of mitochondrial amidoxime reducing components 1 and 2 and mitochondrial cytochrome b5 in N-reductive metabolism in human cells. J Biol Chem 2013; 288:20228-37. [PMID: 23703616 PMCID: PMC3711290 DOI: 10.1074/jbc.m113.474916] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 05/23/2013] [Indexed: 12/26/2022] Open
Abstract
The mitochondrial amidoxime reducing component mARC is a recently discovered molybdenum enzyme in mammals. mARC is not active as a standalone protein, but together with the electron transport proteins NADH-cytochrome b5 reductase (CYB5R) and cytochrome b5 (CYB5), it catalyzes the reduction of N-hydroxylated compounds such as amidoximes. The mARC-containing enzyme system is therefore considered to be responsible for the activation of amidoxime prodrugs. All hitherto analyzed mammalian genomes code for two mARC genes (also referred to as MOSC1 and MOSC2), which share high sequence similarities. By RNAi experiments in two different human cell lines, we demonstrate for the first time that both mARC proteins are capable of reducing N-hydroxylated substrates in cell metabolism. The extent of involvement is highly dependent on the expression level of the particular mARC protein. Furthermore, the mitochondrial isoform of CYB5 (CYB5B) is clearly identified as an essential component of the mARC-containing N-reductase system in human cells. The participation of the microsomal isoform (CYB5A) in N-reduction could be excluded by siRNA-mediated down-regulation in HEK-293 cells and knock-out in mice. Using heme-free apo-CYB5, the contribution of mitochondrial CYB5 to N-reductive catalysis was proven to strictly depend on heme. Finally, we created recombinant CYB5B variants corresponding to four nonsynonymous single nucleotide polymorphisms (SNPs). Investigated mutations of the heme protein seemed to have no significant impact on N-reductive activity of the reconstituted enzyme system.
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Affiliation(s)
- Birte Plitzko
- From the Department of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Christian-Albrechts-University of Kiel, 24118 Kiel, Germany
| | - Gudrun Ott
- From the Department of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Christian-Albrechts-University of Kiel, 24118 Kiel, Germany
| | - Debora Reichmann
- the Department of Plant Biology, Braunschweig University of Technology, 38023 Braunschweig, Germany, and
| | - Colin J. Henderson
- the University of Dundee Medical Research Institute, Jacqui Wood Cancer Centre, Ninewells Hospital and Medical School, Dundee DD1 9SY, Scotland, United Kingdom
| | - C. Roland Wolf
- the University of Dundee Medical Research Institute, Jacqui Wood Cancer Centre, Ninewells Hospital and Medical School, Dundee DD1 9SY, Scotland, United Kingdom
| | - Ralf Mendel
- the Department of Plant Biology, Braunschweig University of Technology, 38023 Braunschweig, Germany, and
| | - Florian Bittner
- the Department of Plant Biology, Braunschweig University of Technology, 38023 Braunschweig, Germany, and
| | - Bernd Clement
- From the Department of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Christian-Albrechts-University of Kiel, 24118 Kiel, Germany
| | - Antje Havemeyer
- From the Department of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Christian-Albrechts-University of Kiel, 24118 Kiel, Germany
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Tejada-Jiménez M, Chamizo-Ampudia A, Galván A, Fernández E, Llamas Á. Molybdenum metabolism in plants. Metallomics 2013; 5:1191-203. [DOI: 10.1039/c3mt00078h] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Yamashita-Sugahara Y, Tokuzawa Y, Nakachi Y, Kanesaki-Yatsuka Y, Matsumoto M, Mizuno Y, Okazaki Y. Fam57b (family with sequence similarity 57, member B), a novel peroxisome proliferator-activated receptor γ target gene that regulates adipogenesis through ceramide synthesis. J Biol Chem 2012; 288:4522-37. [PMID: 23275342 DOI: 10.1074/jbc.m112.440792] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
This report identifies a novel gene encoding Fam57b (family with sequence similarity 57, member B) as a novel peroxisome proliferator-activated receptor γ (PPARγ)-responsive transmembrane gene that is related to obesity. The gene was identified based on an integrated bioinformatics analysis of the following three expression profiling data sets: adipocyte differentiation of mouse stromal cells (ST2 cells), adipose tissues from obesity mice, and siRNA-mediated knockdown of Pparγ using ST2 cells. Fam57b consists of three variants expressed from different promoters and contains a Tram-Lag1-CLN8 domain that is related to ceramide synthase. Reporter and ChIP assays showed that Fam57b variant 2 is a bona fide PPARγ target gene in ST2 cells. Fam57b was up-regulated during adipocyte differentiation, suggesting that FAM57B is involved in this process. Surprisingly, FAM57B overexpression inhibited adipogenesis, and siRNA-mediated knockdown promoted adipocyte differentiation. Analysis of the ceramide content by lipid assay found that ceramides were in fact augmented in FAM57B-overexpressing ST2 cells. We also confirmed that ceramide inhibits adipogenesis. Therefore, the aforementioned results of FAM57B overexpression and siRNA experiments are reconciled by ceramide synthesis. In summary, we present in vitro evidence showing that PPARγ regulates Fam57b transcription during the adipogenesis of ST2 cells. In addition, our results suggest that PPARγ activation contributes to the regulation of ceramide metabolism during adipogenesis via FAM57B.
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Affiliation(s)
- Yzumi Yamashita-Sugahara
- Division of Functional Genomics and Systems Medicine, Research Center for Genomic Medicine, Saitama Medical University, 1397-1 Yamane, Hidaka City, Saitama 350-1241, Japan
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Klein JM, Busch JD, Potting C, Baker MJ, Langer T, Schwarz G. The mitochondrial amidoxime-reducing component (mARC1) is a novel signal-anchored protein of the outer mitochondrial membrane. J Biol Chem 2012; 287:42795-803. [PMID: 23086957 DOI: 10.1074/jbc.m112.419424] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The mitochondrial amidoxime-reducing component (mARC) was recently discovered as the fifth eukaryotic molybdenum cofactor-containing enzyme. The human genome encodes two mARC proteins, mARC1 and mARC2, sharing significant homologies with respect to sequence and function. Whereas mARC2 was identified as a mitochondrial enzyme, the subcellular localization of mARC1 has remained uncharacterized, although the similarity of both proteins suggested identical subcellular localizations. In addition, neither mARC1 nor mARC2 could be attributed unambiguously to one of the four mitochondrial subcompartments. Accordingly, mechanisms triggering the subcellular distribution of both enzymes have been unexplored so far. Here, we shed light on the subcellular localization of mARC1 and demonstrate that it is integrated into the outer mitochondrial membrane. The C-terminal catalytic domain of the protein remains exposed to the cytosol and confers an N((in))-C((out)) membrane orientation of mARC1. This localization is triggered by the N terminus of the enzyme, being composed of a weak N-terminal mitochondrial targeting signal and a downstream transmembrane helix. We demonstrate the transmembrane domain of mARC1 to be sufficient for mitochondrial targeting and the N-terminal targeting signal to function as a supportive receptor for the outer mitochondrial membrane. According to its localization and targeting mechanism, we classify mARC1 as a novel signal-anchored mitochondrial protein. During mitochondrial import, mARC1 is not processed, and membrane integration proceeds membrane potential independently but requires external ATP, which finally results in the assembly of mARC1 into high oligomeric protein complexes.
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Affiliation(s)
- Julian M Klein
- Institute of Biochemistry, Department of Chemistry and Center for Molecular Medicine, University of Cologne, 50674 Cologne, Germany
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Krompholz N, Krischkowski C, Reichmann D, Garbe-Schönberg D, Mendel RR, Bittner F, Clement B, Havemeyer A. The mitochondrial Amidoxime Reducing Component (mARC) is involved in detoxification of N-hydroxylated base analogues. Chem Res Toxicol 2012; 25:2443-50. [PMID: 22924387 DOI: 10.1021/tx300298m] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The "mitochondrial Amidoxime Reducing Component" (mARC) is the newly discovered fourth molybdenum enzyme in mammals. All hitherto analyzed mammals express two mARC proteins, referred to as mARC1 and mARC2. Together with their electron transport proteins cytochrome b(5) and NADH cytochrome b(5) reductase, they form a three-component enzyme system and catalyze the reduction of N-hydroxylated prodrugs. Here, we demonstrate the reductive detoxification of toxic and mutagenic N-hydroxylated nucleobases and their corresponding nucleosides by the mammalian mARC-containing enzyme system. The N-reductive activity was found in all tested tissues with the highest detectable conversion rates in liver, kidney, thyroid, and pancreas. According to the presumed localization, the N-reductive activity is most pronounced in enriched mitochondrial fractions. In vitro assays with the respective recombinant three-component enzyme system show that both mARC isoforms are able to reduce N-hydroxylated base analogues, with mARC1 representing the more efficient isoform. On the basis of the high specific activities with N-hydroxylated base analogues relative to other N-hydroxylated substrates, our data suggest that mARC proteins might be involved in protecting cellular DNA from misincorporation of toxic N-hydroxylated base analogues during replication by converting them to the correct purine or pyrimidine bases, respectively.
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Affiliation(s)
- Nina Krompholz
- Pharmaceutical Institute, Christian-Albrechts-University of Kiel, Germany 24118
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