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Adamus JP, Ruszczyńska A, Wyczałkowska-Tomasik A. Molybdenum's Role as an Essential Element in Enzymes Catabolizing Redox Reactions: A Review. Biomolecules 2024; 14:869. [PMID: 39062583 PMCID: PMC11275037 DOI: 10.3390/biom14070869] [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: 06/04/2024] [Revised: 07/05/2024] [Accepted: 07/16/2024] [Indexed: 07/28/2024] Open
Abstract
Molybdenum (Mo) is an essential element for human life, acting as a cofactor in various enzymes crucial for metabolic homeostasis. This review provides a comprehensive insight into the latest advances in research on molybdenum-containing enzymes and their clinical significance. One of these enzymes is xanthine oxidase (XO), which plays a pivotal role in purine catabolism, generating reactive oxygen species (ROS) capable of inducing oxidative stress and subsequent organ dysfunction. Elevated XO activity is associated with liver pathologies such as non-alcoholic fatty liver disease (NAFLD) and hepatocellular carcinoma (HCC). Aldehyde oxidases (AOs) are also molybdenum-containing enzymes that, similar to XO, participate in drug metabolism, with notable roles in the oxidation of various substrates. However, beneath its apparent efficacy, AOs' inhibition may impact drug effectiveness and contribute to liver damage induced by hepatotoxins. Another notable molybdenum-enzyme is sulfite oxidase (SOX), which catalyzes the conversion of sulfite to sulfate, crucial for the degradation of sulfur-containing amino acids. Recent research highlights SOX's potential as a diagnostic marker for HCC, offering promising sensitivity and specificity in distinguishing cancerous lesions. The newest member of molybdenum-containing enzymes is mitochondrial amidoxime-reducing component (mARC), involved in drug metabolism and detoxification reactions. Emerging evidence suggests its involvement in liver pathologies such as HCC and NAFLD, indicating its potential as a therapeutic target. Overall, understanding the roles of molybdenum-containing enzymes in human physiology and disease pathology is essential for advancing diagnostic and therapeutic strategies for various health conditions, particularly those related to liver dysfunction. Further research into the molecular mechanisms underlying these enzymes' functions could lead to novel treatments and improved patient outcomes.
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Affiliation(s)
- Jakub Piotr Adamus
- Faculty of Medicine, Medical University of Warsaw, 02-091 Warsaw, Poland
| | - Anna Ruszczyńska
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, 02-089 Warsaw, Poland
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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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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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Klopp C, Struwe MA, Plieth C, Clement B, Scheidig AJ. New Design of an Activity Assay Suitable for High-Throughput Screening of Substrates and Inhibitors of the Mitochondrial Amidoxime Reducing Component (mARC). Anal Chem 2023; 95:12452-12458. [PMID: 37549068 DOI: 10.1021/acs.analchem.3c02109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/09/2023]
Abstract
The mitochondrial amidoxime-reducing component (mARC) is one of the simplest molybdenum-containing enzymes. mARC is among a few known reducing enzymes playing an important role in drug metabolism in mammals. Here, an assay based on the fluorescence of NADH is reported for the rapid detection of substrates and potential inhibitors of mARC. So far unknown inhibitors might be useful for the development of drugs assigned to nonalcoholic fatty liver disease (NAFLD) and similar diseases. Kinetics of reactions catalyzed by mARC can be recorded with high sensitivity and precision. On a microtiter plate scale, the assay presented could be applied for high-throughput screening of substance libraries and detection of novel mARC substrate candidates. For instance, molnupiravir was also identified as a new substrate by this assay. For better comparison for such substances, the inhibitor or substrate-to-BAO ratio was introduced. After normalization of enzyme activities to the standard benzamidoxime, substrates can reproducibly be classified.
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Affiliation(s)
- Cathrin Klopp
- Pharmaceutical Institute - Medicinal Chemistry, Kiel University, Gutenbergstraße 76, 24118 Kiel, Germany
- Zoological Institute - Structural Biology, Kiel University, Am Botanischen Garten 9, 24118 Kiel, Germany
| | - Michel A Struwe
- Pharmaceutical Institute - Medicinal Chemistry, Kiel University, Gutenbergstraße 76, 24118 Kiel, Germany
- Zoological Institute - Structural Biology, Kiel University, Am Botanischen Garten 9, 24118 Kiel, Germany
| | - Christoph Plieth
- Centre for Biochemistry and Molecular Biology, Kiel University, Am Botanischen Garten 9, 24118 Kiel, Germany
| | - Bernd Clement
- Pharmaceutical Institute - Medicinal Chemistry, Kiel University, Gutenbergstraße 76, 24118 Kiel, Germany
| | - Axel J Scheidig
- Zoological Institute - Structural Biology, Kiel University, Am Botanischen Garten 9, 24118 Kiel, Germany
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Tejada-Jimenez M, Leon-Miranda E, Llamas A. Chlamydomonas reinhardtii-A Reference Microorganism for Eukaryotic Molybdenum Metabolism. Microorganisms 2023; 11:1671. [PMID: 37512844 PMCID: PMC10385300 DOI: 10.3390/microorganisms11071671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 06/19/2023] [Accepted: 06/23/2023] [Indexed: 07/30/2023] Open
Abstract
Molybdenum (Mo) is vital for the activity of a small but essential group of enzymes called molybdoenzymes. So far, specifically five molybdoenzymes have been discovered in eukaryotes: nitrate reductase, sulfite oxidase, xanthine dehydrogenase, aldehyde oxidase, and mARC. In order to become biologically active, Mo must be chelated to a pterin, forming the so-called Mo cofactor (Moco). Deficiency or mutation in any of the genes involved in Moco biosynthesis results in the simultaneous loss of activity of all molybdoenzymes, fully or partially preventing the normal development of the affected organism. To prevent this, the different mechanisms involved in Mo homeostasis must be finely regulated. Chlamydomonas reinhardtii is a unicellular, photosynthetic, eukaryotic microalga that has produced fundamental advances in key steps of Mo homeostasis over the last 30 years, which have been extrapolated to higher organisms, both plants and animals. These advances include the identification of the first two molybdate transporters in eukaryotes (MOT1 and MOT2), the characterization of key genes in Moco biosynthesis, the identification of the first enzyme that protects and transfers Moco (MCP1), the first characterization of mARC in plants, and the discovery of the crucial role of the nitrate reductase-mARC complex in plant nitric oxide production. This review aims to provide a comprehensive summary of the progress achieved in using C. reinhardtii as a model organism in Mo homeostasis and to propose how this microalga can continue improving with the advancements in this field in the future.
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Affiliation(s)
- Manuel Tejada-Jimenez
- Department of Biochemistry and Molecular Biology, Campus de Rabanales and Campus Internacional de Excelencia Agroalimentario (CeiA3), Edificio Severo Ochoa, University of Córdoba, 14071 Córdoba, Spain
| | - Esperanza Leon-Miranda
- Department of Biochemistry and Molecular Biology, Campus de Rabanales and Campus Internacional de Excelencia Agroalimentario (CeiA3), Edificio Severo Ochoa, University of Córdoba, 14071 Córdoba, Spain
| | - Angel Llamas
- Department of Biochemistry and Molecular Biology, Campus de Rabanales and Campus Internacional de Excelencia Agroalimentario (CeiA3), Edificio Severo Ochoa, University of Córdoba, 14071 Córdoba, Spain
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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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Kalinowski P, Smyk W, Nowosad M, Paluszkiewicz R, Michałowski Ł, Ziarkiewicz-Wróblewska B, Weber SN, Milkiewicz P, Lammert F, Zieniewicz K, Krawczyk M. MTARC1 and HSD17B13 Variants Have Protective Effects on Non-Alcoholic Fatty Liver Disease in Patients Undergoing Bariatric Surgery. Int J Mol Sci 2022; 23:ijms232415825. [PMID: 36555467 PMCID: PMC9781679 DOI: 10.3390/ijms232415825] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/08/2022] [Accepted: 12/09/2022] [Indexed: 12/23/2022] Open
Abstract
The severity of hepatic steatosis is modulated by genetic variants, such as patatin-like phospholipase domain containing 3 (PNPLA3) rs738409, transmembrane 6 superfamily member 2 (TM6SF2) rs58542926, and membrane-bound O-acyltransferase domain containing 7 (MBOAT7) rs641738. Recently, mitochondrial amidoxime reducing component 1 (MTARC1) rs2642438 and hydroxysteroid 17-beta dehydrogenase 13 (HSD17B13) rs72613567 polymorphisms were shown to have protective effects on liver diseases. Here, we evaluate these variants in patients undergoing bariatric surgery. A total of 165 patients who underwent laparoscopic sleeve gastrectomy and intraoperative liver biopsies and 314 controls were prospectively recruited. Genotyping was performed using TaqMan assays. Overall, 70.3% of operated patients presented with hepatic steatosis. NASH (non-alcoholic steatohepatitis) was detected in 28.5% of patients; none had cirrhosis. The increment of liver fibrosis stage was associated with decreasing frequency of the MTARC1 minor allele (p = 0.03). In multivariate analysis MTARC1 was an independent protective factor against fibrosis ≥ 1b (OR = 0.52, p = 0.03) and ≥ 1c (OR = 0.51, p = 0.04). The PNPLA3 risk allele was associated with increased hepatic steatosis, fibrosis, and NASH (OR = 2.22, p = 0.04). The HSD17B13 polymorphism was protective against liver injury as reflected by lower AST (p = 0.04) and ALT (p = 0.03) activities. The TM6SF2 polymorphism was associated with increased ALT (p = 0.04). In conclusion, hepatic steatosis is common among patients scheduled for bariatric surgery, but the MTARC1 and HSD17B13 polymorphisms lower liver injury in these individuals.
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Affiliation(s)
- Piotr Kalinowski
- Department of General, Transplant and Liver Surgery, Medical University of Warsaw, 02-091 Warsaw, Poland
| | - Wiktor Smyk
- Department of Gastroenterology and Hepatology, Medical University of Gdansk, 80-210 Gdansk, Poland
| | - Małgorzata Nowosad
- Department of General, Transplant and Liver Surgery, Medical University of Warsaw, 02-091 Warsaw, Poland
| | - Rafał Paluszkiewicz
- Department of General, Transplant and Liver Surgery, Medical University of Warsaw, 02-091 Warsaw, Poland
| | - Łukasz Michałowski
- Department of Pathology, Medical University of Warsaw, 02-091 Warsaw, Poland
| | | | - Susanne N. Weber
- Department of Medicine II, Saarland University Medical Center, Saarland University, 66421 Homburg, Germany
| | - Piotr Milkiewicz
- Liver and Internal Medicine Unit, Department of General, Transplant and Liver Surgery, Medical University of Warsaw, 02-091 Warsaw, Poland
| | - Frank Lammert
- Department of Medicine II, Saarland University Medical Center, Saarland University, 66421 Homburg, Germany
- Hannover Health Science Campus, Hannover Medical School (MHH), 30625 Hannover, Germany
| | - Krzysztof Zieniewicz
- Department of General, Transplant and Liver Surgery, Medical University of Warsaw, 02-091 Warsaw, Poland
| | - Marcin Krawczyk
- Department of Medicine II, Saarland University Medical Center, Saarland University, 66421 Homburg, Germany
- Laboratory of Metabolic Liver Diseases, Department of General, Transplant and Liver Surgery, Centre for Preclinical Research, Medical University of Warsaw, 02-091 Warsaw, Poland
- Correspondence: ; Tel.: +49-684-1116-15000
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Zapiter J, Harmer JR, Struwe M, Scheidig A, Clement B, Bernhardt PV. Enzyme Electrode Biosensors for N-Hydroxylated Prodrugs Incorporating the Mitochondrial Amidoxime Reducing Component. Anal Chem 2022; 94:9208-9215. [PMID: 35700342 DOI: 10.1021/acs.analchem.2c02232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Human mitochondrial amidoxime reducing component 1 and 2 (mARC1 and mARC2) were immobilised on glassy carbon electrodes using the crosslinker glutaraldehyde. Voltammetry was performed in the presence of the artificial electron transfer mediator methyl viologen, whose redox potential lies negative of the enzymes' MoVI/V and MoV/IV redox potentials which were determined from optical spectroelectrochemical and EPR measurements. Apparent Michaelis constants obtained from catalytic limiting currents at various substrate concentrations were comparable to those previously reported in the literature from enzymatic assays. Kinetic parameters for benzamidoxime reduction were determined from cyclic voltammograms simulated using Digisim. pH dependence and stability of the enzyme electrode with time were also determined from limiting catalytic currents in saturating concentrations of benzamidoxime. The same electrode remained active after at least 9 days. Fabrication of this versatile and cost-effective biosensor is effective in screening new pharmaceutically important substrates and mARC inhibitors.
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Affiliation(s)
- Joan Zapiter
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane 4072, Australia
| | - Jeffrey R Harmer
- Centre for Advanced Imaging, The University of Queensland, Brisbane 4072, Australia
| | - Michel Struwe
- Pharmazeutisches Institut, Universität Kiel, Gutenbergstraße 76, Kiel 24118, Germany.,Zoologisches Institut/Strukturbiologie, Am Botanischen Garten 11, Kiel 24118, Germany
| | - Axel Scheidig
- Zoologisches Institut/Strukturbiologie, Am Botanischen Garten 11, Kiel 24118, Germany
| | - Bernd Clement
- Pharmazeutisches Institut, Universität Kiel, Gutenbergstraße 76, Kiel 24118, Germany
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane 4072, Australia
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RNA Sequencing of Whole Blood Defines the Signature of High Intensity Exercise at Altitude in Elite Speed Skaters. Genes (Basel) 2022; 13:genes13040574. [PMID: 35456380 PMCID: PMC9027771 DOI: 10.3390/genes13040574] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 03/08/2022] [Accepted: 03/21/2022] [Indexed: 12/18/2022] Open
Abstract
Although high altitude training has been increasingly popular among endurance athletes, the molecular and cellular bases of this adaptation remain poorly understood. We aimed to define the underlying physiological changes and screen for potential biomarkers of adaptation using transcriptional profiling of whole blood. Seven elite female speed skaters were profiled on the 18th day of high-altitude adaptation. Whole blood RNA-seq before and after an intense 1 h skating bout was used to measure gene expression changes associated with exercise. In order to identify the genes specifically regulated at high altitudes, we have leveraged the data from eight previously published microarray datasets studying blood expression changes after exercise at sea level. Using cell type-specific signatures, we were able to deconvolute changes of cell type abundance from individual gene expression changes. Among these were PHOSPHO1, with a known role in erythropoiesis, and MARC1 with a role in endogenic NO metabolism. We find that platelet and erythrocyte counts uniquely respond to altitude exercise, while changes in neutrophils represent a more generic marker of intense exercise. Publicly available data from both single cell atlases and exercise-related blood profiling dramatically increases the value of whole blood RNA-seq for the dynamic evaluation of physiological changes in an athlete’s body.
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Ahire D, Basit A, Christopher LJ, Iyer R, Leeder JS, Prasad B. Interindividual Variability and Differential Tissue Abundance of Mitochondrial Amidoxime Reducing Component Enzymes in Humans. Drug Metab Dispos 2022; 50:191-196. [PMID: 34949674 PMCID: PMC8969132 DOI: 10.1124/dmd.121.000805] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 12/17/2021] [Indexed: 11/22/2022] Open
Abstract
Mitochondrial amidoxime-reducing component (mARC) enzymes are molybdenum-containing proteins that metabolize a number of endobiotics and xenobiotics. The interindividual variability and differential tissue abundance of mARC1 and mARC2 were quantified using targeted proteomics in three types of tissue fractions: 1) pediatric liver tissue homogenates, 2) total membrane fraction of the paired liver and kidney samples from pediatric and adult donors, and 3) pooled S9 fractions of the liver, intestine, kidney, lung, and heart. The absolute levels of mARC1 and mARC2 in the pediatric liver homogenate were 40.08 ± 4.26 and 24.58 ± 4.02 pmol/mg homogenate protein, respectively, and were independent of age and sex. In the total membrane fraction of the paired liver and kidney samples, the abundance of hepatic mARC1 and mARC2 was comparable, whereas mARC2 abundance in the kidney was approximately 9-fold higher in comparison with mARC1. The analysis of the third set of samples (i.e., S9 fraction) revealed that mARC1 abundance in the kidney, intestine, and lung was 5- to 13-fold lower than the liver S9 abundance, whereas mARC2 abundance was approximately 3- and 16-fold lower in the intestine and lung than the liver S9, respectively. In contrast, the kidney mARC2 abundance in the S9 fraction was approximately 2.5-fold higher as compared with the hepatic mARC2 abundance. The abundance of mARC enzymes in the heart was below the limit of quantification (∼0.6 pmol/mg protein). The mARC enzyme abundance data presented here can be used to develop physiologically based pharmacokinetic models for the prediction of in vivo pharmacokinetics of mARC substrates. SIGNIFICANCE STATEMENT: A precise targeted quantitative proteomics method was developed and applied to quantify newly discovered drug-metabolizing enzymes, mARC1 and mARC2, in pediatric and adult tissue samples. The data suggest that mARC enzymes are ubiquitously expressed in an isoform-specific manner in the human liver, kidney, intestine, and lung, and the enzyme abundance is not associated with age and sex. These data are important for developing physiologically based pharmacokinetic models for the prediction of in vivo pharmacokinetics of mARC substrates.
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Affiliation(s)
| | | | | | | | | | - Bhagwat Prasad
- Department of Pharmaceutical Sciences, Washington State University, Spokane, Washington (D.A., A.B., B.P.); Department of Nonclinical Disposition and Bioanalysis, Bristol Myers Squibb, Princeton, New Jersey (L.J.C., R.I.); and Department of Pediatrics, Children's Mercy Hospitals and Clinics, Kansas City, Missouri (J.S.L.)
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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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12
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Zhu X, Xia M, Gao X. Update on genetics and epigenetics in metabolic associated fatty liver disease. Ther Adv Endocrinol Metab 2022; 13:20420188221132138. [PMID: 36325500 PMCID: PMC9619279 DOI: 10.1177/20420188221132138] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 09/25/2022] [Indexed: 11/06/2022] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is becoming the most frequent chronic liver disease worldwide. Metabolic (dysfunction) associated fatty liver disease (MAFLD) is suggested to replace the nomenclature of NAFLD. For individuals with metabolic dysfunction, multiple NAFLD-related factors also contribute to the development and progression of MAFLD including genetics and epigenetics. The application of genome-wide association study (GWAS) and exome-wide association study (EWAS) uncovers single-nucleotide polymorphisms (SNPs) in MAFLD. In addition to the classic SNPs in PNPLA3, TM6SF2, and GCKR, some new SNPs have been found recently to contribute to the pathogenesis of liver steatosis. Epigenetic factors involving DNA methylation, histone modifications, non-coding RNAs regulations, and RNA methylation also play a critical role in MAFLD. DNA methylation is the most reported epigenetic modification. Developing a non-invasion biomarker to distinguish metabolic steatohepatitis (MASH) or liver fibrosis is ongoing. In this review, we summarized and discussed the latest progress in genetic and epigenetic factors of NAFLD/MAFLD, in order to provide potential clues for MAFLD treatment.
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Affiliation(s)
- Xiaopeng Zhu
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan Institute for Metabolic Diseases, Fudan University, Shanghai, China
| | | | - Xin Gao
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan Institute for Metabolic Diseases, Fudan University, Shanghai, China
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Angelova PR. Sources and triggers of oxidative damage in neurodegeneration. Free Radic Biol Med 2021; 173:52-63. [PMID: 34224816 DOI: 10.1016/j.freeradbiomed.2021.07.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 06/19/2021] [Accepted: 07/01/2021] [Indexed: 02/07/2023]
Abstract
Neurodegeneration describes a group of more than 300 neurological diseases, characterised by neuronal loss and intra- or extracellular protein depositions, as key neuropathological features. Multiple factors play role in the pathogenesis of these group of disorders: mitochondrial dysfunction, membrane damage, calcium dyshomeostasis, metallostasis, defect clearance and renewal mechanisms, to name a few. All these factors, without exceptions, have in common the involvement of immensely increased generation of free radicals and occurrence of oxidative stress, and as a result - exhaustion of the scavenging potency of the cellular redox defence mechanisms. Besides genetic predisposition and environmental exposure to toxins, the main risk factor for developing neurodegeneration is age. And although the "Free radical theory of ageing" was declared dead, it is undisputable that accumulation of damage occurs with age, especially in systems that are regulated by free radical messengers and those that oppose oxidative stress, protein oxidation and the accuracy in protein synthesis and degradation machinery has difficulties to be maintained. This brief review provides a comprehensive summary on the main sources of free radical damage, occurring in the setting of neurodegeneration.
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14
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Innes H, Buch S, Hutchinson S, Guha IN, Morling JR, Barnes E, Irving W, Forrest E, Pedergnana V, Goldberg D, Aspinall E, Barclay S, Hayes PC, Dillon J, Nischalke HD, Lutz P, Spengler U, Fischer J, Berg T, Brosch M, Eyer F, Datz C, Mueller S, Peccerella T, Deltenre P, Marot A, Soyka M, McQuillin A, Morgan MY, Hampe J, Stickel F. Genome-Wide Association Study for Alcohol-Related Cirrhosis Identifies Risk Loci in MARC1 and HNRNPUL1. Gastroenterology 2020; 159:1276-1289.e7. [PMID: 32561361 DOI: 10.1053/j.gastro.2020.06.014] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 05/10/2020] [Accepted: 06/05/2020] [Indexed: 12/13/2022]
Abstract
BACKGROUND AND AIMS Little is known about genetic factors that affect development of alcohol-related cirrhosis. We performed a genome-wide association study (GWAS) of samples from the United Kingdom Biobank (UKB) to identify polymorphisms associated with risk of alcohol-related liver disease. METHODS We performed a GWAS of 35,839 participants in the UKB with high intake of alcohol against markers of hepatic fibrosis (FIB-4, APRI, and Forns index scores) and hepatocellular injury (levels of aminotransferases). Loci identified in the discovery analysis were tested for their association with alcohol-related cirrhosis in 3 separate European cohorts (phase 1 validation cohort; n=2545). Variants associated with alcohol-related cirrhosis in the validation at a false discovery rate of less than 20% were then directly genotyped in 2 additional European validation cohorts (phase 2 validation, n=2068). RESULTS In the GWAS of the discovery cohort, we identified 50 independent risk loci with genome-wide significance (P < 5 × 10-8). Nine of these loci were significantly associated with alcohol-related cirrhosis in the phase 1 validation cohort; 6 of these 9 loci were significantly associated with alcohol-related cirrhosis in phase 2 validation cohort, at a false discovery rate below 5%. The loci included variants in the mitochondrial amidoxime reducing component 1 gene (MARC1) and the heterogeneous nuclear ribonucleoprotein U like 1 gene (HNRNPUL1). After we adjusted for age, sex, body mass index, and type-2 diabetes in the phase 2 validation cohort, the minor A allele of MARC1:rs2642438 was associated with reduced risk of alcohol-related cirrhosis (adjusted odds ratio, 0.76; P=.0027); conversely, the minor C allele of HNRNPUL1:rs15052 was associated with an increased risk of alcohol-related cirrhosis (adjusted odds ratio, 1.30; P=.020). CONCLUSIONS In a GWAS of samples from the UKB, we identified and validated (in 5 European cohorts) single-nucleotide polymorphisms that affect risk of alcohol-related cirrhosis in opposite directions: the minor A allele in MARC1:rs2642438 decreases risk, whereas the minor C allele in HNRNPUL1:rs15052 increases risk.
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Affiliation(s)
- Hamish Innes
- School of Health and Life Sciences, Glasgow Caledonian University, Glasgow United Kingdom; Division of Epidemiology and Public Health, University of Nottingham, Nottingham, United Kingdom; Health Protection Scotland, Glasgow, United Kingdom.
| | - Stephan Buch
- Medical Department 1, University Hospital Dresden, Technische Universität Dresden, Germany
| | - Sharon Hutchinson
- School of Health and Life Sciences, Glasgow Caledonian University, Glasgow United Kingdom; Health Protection Scotland, Glasgow, United Kingdom
| | - Indra Neil Guha
- National Institute for Health Research Nottingham Biomedical Research Centre, Nottingham University Hospitals National Health Service Trust and the University of Nottingham, Nottingham, United Kingdom
| | - Joanne R Morling
- Division of Epidemiology and Public Health, University of Nottingham, Nottingham, United Kingdom; National Institute for Health Research Nottingham Biomedical Research Centre, Nottingham University Hospitals National Health Service Trust and the University of Nottingham, Nottingham, United Kingdom
| | - Eleanor Barnes
- Peter Medawar Building for Pathogen Research, Nuffield Department of Medicine, and the Oxford National Institute for Health Research Biomedical Research Centre, Oxford University, United Kingdom
| | - Will Irving
- National Institute for Health Research Nottingham Biomedical Research Centre, Nottingham University Hospitals National Health Service Trust and the University of Nottingham, Nottingham, United Kingdom
| | - Ewan Forrest
- Glasgow Royal Infirmary, Glasgow, United Kingdom
| | - Vincent Pedergnana
- Laboratoire Maladies Infectieuses et Vecteurs Écologie, Génétique, Évolution et Contrôl (UMR CNRS 5290, UR IRD 224, UM), Montpellier, France
| | - David Goldberg
- School of Health and Life Sciences, Glasgow Caledonian University, Glasgow United Kingdom; Health Protection Scotland, Glasgow, United Kingdom
| | - Esther Aspinall
- School of Health and Life Sciences, Glasgow Caledonian University, Glasgow United Kingdom; Health Protection Scotland, Glasgow, United Kingdom
| | | | - Peter C Hayes
- Royal Infirmary Edinburgh, Edinburgh, United Kingdom
| | - John Dillon
- School of Medicine, University of Dundee, Dundee, United Kingdom
| | | | - Philipp Lutz
- Department of Internal Medicine I, University of Bonn, Bonn, Germany
| | - Ulrich Spengler
- Department of Internal Medicine I, University of Bonn, Bonn, Germany
| | - Janett Fischer
- Division of Hepatology, Department of Medicine II, Leipzig University Medical Center, Leipzig, Germany
| | - Thomas Berg
- Division of Hepatology, Department of Medicine II, Leipzig University Medical Center, Leipzig, Germany
| | - Mario Brosch
- Medical Department 1, University Hospital Dresden, Technische Universität Dresden, Germany
| | - Florian Eyer
- Department of Clinical Toxicology, Klinikum Rechts der Isar, Technical University of Munich, Germany
| | - Christian Datz
- Department of Internal Medicine, Hospital Oberndorf, Teaching Hospital of the Paracelsus Private Medical University of Salzburg, Oberndorf, Austria
| | - Sebastian Mueller
- Department of Internal Medicine and Center for Alcohol Research, Salem Medical Center University Hospital Heidelberg, Heidelberg, Germany
| | - Teresa Peccerella
- Department of Internal Medicine and Center for Alcohol Research, Salem Medical Center University Hospital Heidelberg, Heidelberg, Germany
| | - Pierre Deltenre
- Division of Gastroenterology and Hepatology, Centre Hospitalier Universitaire Vaudois, University of Lausanne, Switzerland
| | - Astrid Marot
- Division of Gastroenterology and Hepatology, Centre Hospitalier Universitaire Vaudois, University of Lausanne, Switzerland
| | - Michael Soyka
- Psychiatric hospital, University of Munich, Munich, Germany, and Department of Psychiatry, Meiringen Hospital, Meiringen, Switzerland
| | - Andrew McQuillin
- Molecular Psychiatry Laboratory, Division of Psychiatry, University College London, London, United Kingdom
| | - Marsha Y Morgan
- Division of Medicine, University College London Institute for Liver & Digestive Health, Royal Free Campus, University College London, London, United Kingdom
| | - Jochen Hampe
- Medical Department 1, University Hospital Dresden, Technische Universität Dresden, Germany
| | - Felix Stickel
- Department of Gastroenterology and Hepatology, University Hospital of Zurich, Zurich, Switzerland
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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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16
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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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17
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Krawczyk M, Liebe R, Lammert F. Toward Genetic Prediction of Nonalcoholic Fatty Liver Disease Trajectories: PNPLA3 and Beyond. Gastroenterology 2020; 158:1865-1880.e1. [PMID: 32068025 DOI: 10.1053/j.gastro.2020.01.053] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 01/29/2020] [Accepted: 01/29/2020] [Indexed: 12/14/2022]
Abstract
Nonalcoholic fatty liver disease (NAFLD) is on the verge of becoming the leading cause of liver disease. NAFLD develops at the interface between environmental factors and inherited predisposition. Genome-wide association studies, followed by exome-wide analyses, led to identification of genetic risk variants (eg, PNPLA3, TM6SF2, and SERPINA1) and key pathways involved in fatty liver disease pathobiology. Functional studies improved our understanding of these genetic factors and the molecular mechanisms underlying the trajectories from fat accumulation to fibrosis, cirrhosis, and cancer over time. Here, we summarize key NAFLD risk genes and illustrate their interactions in a 3-dimensional "risk space." Although NAFLD genomics sometimes appears to be "lost in translation," we envision clinical utility in trial design, outcome prediction, and NAFLD surveillance.
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Affiliation(s)
- Marcin Krawczyk
- Department of Medicine II (Gastroenterology and Endocrinology), Saarland University Medical Center, Saarland University, Homburg; Laboratory of Metabolic Liver Diseases, Center for Preclinical Research, Department of General, Transplant and Liver Surgery, Medical University of Warsaw, Warsaw, Poland
| | - Roman Liebe
- Department of Medicine II (Gastroenterology and Endocrinology), Saarland University Medical Center, Saarland University, Homburg; Department of Gastroenterology, Hepatology and Infectious Diseases, University Hospital Düsseldorf, Heinrich Heine University, Düsseldorf, Germany
| | - Frank Lammert
- Department of Medicine II (Gastroenterology and Endocrinology), Saarland University Medical Center, Saarland University, Homburg.
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18
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Functional mononuclear molybdenum enzymes: challenges and triumphs in molecular cloning, expression, and isolation. J Biol Inorg Chem 2020; 25:547-569. [PMID: 32279136 DOI: 10.1007/s00775-020-01787-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 03/30/2020] [Indexed: 10/24/2022]
Abstract
Mononuclear molybdenum enzymes catalyze a variety of reactions that are essential in the cycling of nitrogen, carbon, arsenic, and sulfur. For decades, the structure and function of these crucial enzymes have been investigated to develop a fundamental knowledge for this vast family of enzymes and the chemistries they carry out. Therefore, obtaining abundant quantities of active enzyme is necessary for exploring this family's biochemical capability. This mini-review summarizes the methods for overexpressing mononuclear molybdenum enzymes in the context of the challenges encountered in the process. Effective methods for molybdenum cofactor synthesis and incorporation, optimization of expression conditions, improving isolation of active vs. inactive enzyme, incorporation of additional prosthetic groups, and inclusion of redox enzyme maturation protein chaperones are discussed in relation to the current molybdenum enzyme literature. This article summarizes the heterologous and homologous expression studies providing underlying patterns and potential future directions.
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19
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Romano A, Parrinello NL, Simeon V, Puglisi F, La Cava P, Bellofiore C, Giallongo C, Camiolo G, D'Auria F, Grieco V, Larocca F, Barbato A, Cambria D, La Spina E, Tibullo D, Palumbo GA, Conticello C, Musto P, Di Raimondo F. High-density neutrophils in MGUS and multiple myeloma are dysfunctional and immune-suppressive due to increased STAT3 downstream signaling. Sci Rep 2020; 10:1983. [PMID: 32029833 PMCID: PMC7005058 DOI: 10.1038/s41598-020-58859-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 01/06/2020] [Indexed: 02/07/2023] Open
Abstract
To understand neutrophil impairment in the progression from MGUS through active MM, we investigated the function of mature, high-density neutrophils (HDNs), isolated from peripheral blood. In 7 MM, 3 MGUS and 3 healthy subjects by gene expression profile, we identified a total of 551 upregulated and 343 downregulated genes in MM-HDN, involved in chemokine signaling pathway and FC-gamma receptor mediated phagocytosis conveying in the activation of STAT proteins. In a series of 60 newly diagnosed MM and 30 MGUS patients, by flow-cytometry we found that HDN from MM, and to a lesser extend MGUS, had an up-regulation of the inducible FcγRI (also known as CD64) and a down-regulation of the constitutive FcγRIIIa (also known as CD16) together with a reduced phagocytic activity and oxidative burst, associated to increased immune-suppression that could be reverted by arginase inhibitors in co-culture with lymphocytes. In 43 consecutive newly-diagnosed MM patients, who received first-line treatment based on bortezomib, thalidomide and dexamethasone, high CD64 could identify at diagnosis patients with inferior median overall survival (39.5 versus 86.7 months, p = 0.04). Thus, HDNs are significantly different among healthy, MGUS and MM subjects. In both MGUS and MM neutrophils may play a role in supporting both the increased susceptibility to infection and the immunological dysfunction that leads to tumor progression.
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Affiliation(s)
- A Romano
- Department of Surgery and Medical Specialties, University of Catania, Catania, Italy
- Division of Hematology, Azienda Ospedaliera Policlinico e Vittorio Emanuele di Catania, Catania, Italy
| | - N L Parrinello
- Division of Hematology, Azienda Ospedaliera Policlinico e Vittorio Emanuele di Catania, Catania, Italy
- Dipartimento di Scienze Mediche, Chirurgiche e Tecnologie Avanzate "G.F. Ingrassia", University of Catania, Catania, Italy
| | - V Simeon
- Laboratory of Pre-Clinical Research and Advanced Diagnostics, IRCCS-CROB, Rionero in Vulture (Pz), Potenza, Italy
- Department of Mental Health and Preventive Medicine, Medical Statistics Unit, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - F Puglisi
- Division of Hematology, Azienda Ospedaliera Policlinico e Vittorio Emanuele di Catania, Catania, Italy
| | - P La Cava
- Division of Hematology, Azienda Ospedaliera Policlinico e Vittorio Emanuele di Catania, Catania, Italy
| | - C Bellofiore
- Department of Surgery and Medical Specialties, University of Catania, Catania, Italy
- Division of Hematology, Azienda Ospedaliera Policlinico e Vittorio Emanuele di Catania, Catania, Italy
| | - C Giallongo
- Division of Hematology, Azienda Ospedaliera Policlinico e Vittorio Emanuele di Catania, Catania, Italy
| | - G Camiolo
- Division of Hematology, Azienda Ospedaliera Policlinico e Vittorio Emanuele di Catania, Catania, Italy
| | - F D'Auria
- Laboratory of Pre-Clinical Research and Advanced Diagnostics, IRCCS-CROB, Rionero in Vulture (Pz), Potenza, Italy
| | - V Grieco
- Laboratory of Pre-Clinical Research and Advanced Diagnostics, IRCCS-CROB, Rionero in Vulture (Pz), Potenza, Italy
| | - F Larocca
- Laboratory of Pre-Clinical Research and Advanced Diagnostics, IRCCS-CROB, Rionero in Vulture (Pz), Potenza, Italy
| | - A Barbato
- Division of Hematology, Azienda Ospedaliera Policlinico e Vittorio Emanuele di Catania, Catania, Italy
| | - D Cambria
- Division of Hematology, Azienda Ospedaliera Policlinico e Vittorio Emanuele di Catania, Catania, Italy
| | - E La Spina
- Biometec, Dipartimento di Scienze Biomediche e Biotecnologiche, University of Catania, Catania, Italy
| | - D Tibullo
- Biometec, Dipartimento di Scienze Biomediche e Biotecnologiche, University of Catania, Catania, Italy
| | - G A Palumbo
- Division of Hematology, Azienda Ospedaliera Policlinico e Vittorio Emanuele di Catania, Catania, Italy
- Dipartimento di Scienze Mediche, Chirurgiche e Tecnologie Avanzate "G.F. Ingrassia", University of Catania, Catania, Italy
| | - C Conticello
- Division of Hematology, Azienda Ospedaliera Policlinico e Vittorio Emanuele di Catania, Catania, Italy
| | - P Musto
- Laboratory of Pre-Clinical Research and Advanced Diagnostics, IRCCS-CROB, Rionero in Vulture (Pz), Potenza, Italy
- Chair and Unit of Hematology and Stem Cell Transplantation, Aldo Moro University, Bari, Italy
| | - F Di Raimondo
- Department of Surgery and Medical Specialties, University of Catania, Catania, Italy.
- Division of Hematology, Azienda Ospedaliera Policlinico e Vittorio Emanuele di Catania, Catania, Italy.
- Department of Mental Health and Preventive Medicine, Medical Statistics Unit, University of Campania "Luigi Vanvitelli", Naples, Italy.
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RNA Sequencing of Collecting Duct Renal Cell Carcinoma Suggests an Interaction between miRNA and Target Genes and a Predominance of Deregulated Solute Carrier Genes. Cancers (Basel) 2019; 12:cancers12010064. [PMID: 31878355 PMCID: PMC7017122 DOI: 10.3390/cancers12010064] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 12/19/2019] [Accepted: 12/22/2019] [Indexed: 02/07/2023] Open
Abstract
Collecting duct carcinoma (CDC) is a rare renal cell carcinoma subtype with a very poor prognosis. There have been only a few studies on gene expression analysis in CDCs. We compared the gene expression profiles of two CDC cases with those of eight normal tissues of renal cell carcinoma patients. At a threshold of |log2fold-change| ≥1, 3349 genes were upregulated and 1947 genes were downregulated in CDCs compared to the normal samples. Pathway analysis of the deregulated genes revealed that cancer pathways and cell cycle pathways were most prominent in CDCs. The most upregulated gene was keratin 17, and the most downregulated gene was cubilin. Among the most downregulated genes were four solute carrier genes (SLC3A1, SLC9A3, SLC26A7, and SLC47A1). The strongest negative correlations between miRNAs and mRNAs were found between the downregulated miR-374b-5p and its upregulated target genes HIST1H3B, HK2, and SLC7A11 and between upregulated miR-26b-5p and its downregulated target genes PPARGC1A, ALDH6A1, and MARC2. An upregulation of HK2 and a downregulation of PPARGC1A, ALDH6A1, and MARC2 were observed at the protein level. Survival analysis of the cancer genome atlas (TCGA) dataset showed for the first time that low gene expression of MARC2, cubilin, and SLC47A1 and high gene expression of KRT17 are associated with poor overall survival in clear cell renal cell carcinoma patients. Altogether, we identified dysregulated protein-coding genes, potential miRNA-target interactions, and prognostic markers that could be associated with CDC.
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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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Tejada-Jimenez M, Llamas A, Galván A, Fernández E. Role of Nitrate Reductase in NO Production in Photosynthetic Eukaryotes. PLANTS 2019; 8:plants8030056. [PMID: 30845759 PMCID: PMC6473468 DOI: 10.3390/plants8030056] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 02/06/2019] [Accepted: 02/08/2019] [Indexed: 12/20/2022]
Abstract
Nitric oxide is a gaseous secondary messenger that is critical for proper cell signaling and plant survival when exposed to stress. Nitric oxide (NO) synthesis in plants, under standard phototrophic oxygenic conditions, has long been a very controversial issue. A few algal strains contain NO synthase (NOS), which appears to be absent in all other algae and land plants. The experimental data have led to the hypothesis that molybdoenzyme nitrate reductase (NR) is the main enzyme responsible for NO production in most plants. Recently, NR was found to be a necessary partner in a dual system that also includes another molybdoenzyme, which was renamed NO-forming nitrite reductase (NOFNiR). This enzyme produces NO independently of the molybdenum center of NR and depends on the NR electron transport chain from NAD(P)H to heme. Under the circumstances in which NR is not present or active, the existence of another NO-forming system that is similar to the NOS system would account for NO production and NO effects. PII protein, which senses and integrates the signals of the C–N balance in the cell, likely has an important role in organizing cell responses. Here, we critically analyze these topics.
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Affiliation(s)
- Manuel Tejada-Jimenez
- Departamento de Bioquímica y Biología Molecular, Campus de Rabanales y Campus Internacional de Excelencia Agroalimentario (CeiA3), Edif. Severo Ochoa, Universidad de Córdoba, 14071 Córdoba, Spain.
| | - Angel Llamas
- Departamento de Bioquímica y Biología Molecular, Campus de Rabanales y Campus Internacional de Excelencia Agroalimentario (CeiA3), Edif. Severo Ochoa, Universidad de Córdoba, 14071 Córdoba, Spain.
| | - Aurora Galván
- Departamento de Bioquímica y Biología Molecular, Campus de Rabanales y Campus Internacional de Excelencia Agroalimentario (CeiA3), Edif. Severo Ochoa, Universidad de Córdoba, 14071 Córdoba, Spain.
| | - Emilio Fernández
- Departamento de Bioquímica y Biología Molecular, Campus de Rabanales y Campus Internacional de Excelencia Agroalimentario (CeiA3), Edif. Severo Ochoa, Universidad de Córdoba, 14071 Córdoba, Spain.
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Tejero J, Shiva S, Gladwin MT. Sources of Vascular Nitric Oxide and Reactive Oxygen Species and Their Regulation. Physiol Rev 2019; 99:311-379. [PMID: 30379623 DOI: 10.1152/physrev.00036.2017] [Citation(s) in RCA: 280] [Impact Index Per Article: 56.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Nitric oxide (NO) is a small free radical with critical signaling roles in physiology and pathophysiology. The generation of sufficient NO levels to regulate the resistance of the blood vessels and hence the maintenance of adequate blood flow is critical to the healthy performance of the vasculature. A novel paradigm indicates that classical NO synthesis by dedicated NO synthases is supplemented by nitrite reduction pathways under hypoxia. At the same time, reactive oxygen species (ROS), which include superoxide and hydrogen peroxide, are produced in the vascular system for signaling purposes, as effectors of the immune response, or as byproducts of cellular metabolism. NO and ROS can be generated by distinct enzymes or by the same enzyme through alternate reduction and oxidation processes. The latter oxidoreductase systems include NO synthases, molybdopterin enzymes, and hemoglobins, which can form superoxide by reduction of molecular oxygen or NO by reduction of inorganic nitrite. Enzymatic uncoupling, changes in oxygen tension, and the concentration of coenzymes and reductants can modulate the NO/ROS production from these oxidoreductases and determine the redox balance in health and disease. The dysregulation of the mechanisms involved in the generation of NO and ROS is an important cause of cardiovascular disease and target for therapy. In this review we will present the biology of NO and ROS in the cardiovascular system, with special emphasis on their routes of formation and regulation, as well as the therapeutic challenges and opportunities for the management of NO and ROS in cardiovascular disease.
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Affiliation(s)
- Jesús Tejero
- Pittsburgh Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh , Pittsburgh, Pennsylvania ; Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh , Pittsburgh, Pennsylvania ; Department of Pharmacology and Chemical Biology, University of Pittsburgh , Pittsburgh, Pennsylvania ; and Department of Medicine, Center for Metabolism and Mitochondrial Medicine, University of Pittsburgh , Pittsburgh, Pennsylvania
| | - Sruti Shiva
- Pittsburgh Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh , Pittsburgh, Pennsylvania ; Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh , Pittsburgh, Pennsylvania ; Department of Pharmacology and Chemical Biology, University of Pittsburgh , Pittsburgh, Pennsylvania ; and Department of Medicine, Center for Metabolism and Mitochondrial Medicine, University of Pittsburgh , Pittsburgh, Pennsylvania
| | - Mark T Gladwin
- Pittsburgh Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh , Pittsburgh, Pennsylvania ; Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh , Pittsburgh, Pennsylvania ; Department of Pharmacology and Chemical Biology, University of Pittsburgh , Pittsburgh, Pennsylvania ; and Department of Medicine, Center for Metabolism and Mitochondrial Medicine, University of Pittsburgh , Pittsburgh, Pennsylvania
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24
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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: 16] [Impact Index Per Article: 2.7] [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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Crystal structure of human mARC1 reveals its exceptional position among eukaryotic molybdenum enzymes. Proc Natl Acad Sci U S A 2018; 115:11958-11963. [PMID: 30397129 DOI: 10.1073/pnas.1808576115] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Biotransformation enzymes ensure a viable homeostasis by regulating reversible cycles of oxidative and reductive reactions. The metabolism of nitrogen-containing compounds is of high pharmaceutical and toxicological relevance because N-oxygenated metabolites derived from reactions mediated by cytochrome P450 enzymes or flavin-dependent monooxygenases are in some cases highly toxic or mutagenic. The molybdenum-dependent mitochondrial amidoxime-reducing component (mARC) was found to be an extremely efficient counterpart, which is able to reduce the full range of N-oxygenated compounds and thereby mediates detoxification reactions. However, the 3D structure of this enzyme was unknown. Here we present the high-resolution crystal structure of human mARC. We give detailed insight into the coordination of its molybdenum cofactor (Moco), the catalytic mechanism, and its ability to reduce a wide range of N-oxygenated compounds. The identification of two key residues will allow future discrimination between mARC paralogs and ensure correct annotation. Since our structural findings contradict in silico predictions that are currently made by online databases, we propose domain definitions for members of the superfamily of Moco sulfurase C-terminal (MOSC) domain-containing proteins. Furthermore, we present evidence for an evolutionary role of mARC for the emergence of the xanthine oxidase protein superfamily. We anticipate the hereby presented crystal structure to be a starting point for future descriptions of MOSC proteins, which are currently poorly structurally characterized.
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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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Schneider J, Girreser U, Havemeyer A, Bittner F, Clement B. Detoxification of Trimethylamine N-Oxide by the Mitochondrial Amidoxime Reducing Component mARC. Chem Res Toxicol 2018; 31:447-453. [PMID: 29856598 DOI: 10.1021/acs.chemrestox.7b00329] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Although known for years, the toxic effects of trimethylamine N-oxide (TMAO), a physiological metabolite, were just recently discovered and are currently under investigation. It is known that elevated TMAO plasma levels correlate with an elevated risk for cardiovascular disease (CVD). Even though there is a general consensus about the existence of a causal relationship between TMAO and CVD, the underlying mechanisms are not fully understood. TMAO is an oxidation product of the hepatic flavin-containing monooxygenases (FMO), mainly of isoform 3, and it is conceivable that humans also have an enzyme reversing this toxification by reducing TMAO to its precursor trimethylamine (TMA). All prokaryotic enzymes that use TMAO as a substrate have molybdenum-containing cofactors in common. Such molybdenum-containing enzymes also exist in mammals, with the so-called mitochondrial amidoxime reducing component (mARC) representing the most recently discovered mammalian molybdenum enzyme. The enzyme has been found to exist in two isoforms, mARC1 and mARC2, both being capable of reducing a variety of N-oxygenated compounds, including nonphysiological N-oxides. To investigate whether the two isoforms of this enzyme are able to reduce and detoxify TMAO, we developed a suitable analytical method and tested TMAO reduction with a recombinant enzyme system. We found that one of the two recombinant human mARC proteins, namely, hmARC1, reduces TMAO to TMA. The N-reductive activity is relatively low and identified via the kinetic parameters with Km = (30.4 ± 9.8) mM and Vmax = (100.5 ± 12.2) nmol/(mg protein·min). Nevertheless, the ubiquitous tissue expression of hmARC1 allows a continuous reduction of TMAO whereas the counter-reaction, the production of TMAO through FMO3, can take place only in the liver where FMO3 is expressed. TMAO reduction in porcine liver subfractions showed the characteristic enrichment of N-reductive activity in the outer mitochondrial membrane. TMAO reduction was also found in human cell cultures. These findings indicate the role of hmARC1 in the metabolomic pathway of TMAO, which might contribute to the prevention of CVD. This also hints at a physiological function of the molybdenum enzyme, which remains mainly unknown to date.
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Affiliation(s)
- Jennifer Schneider
- Department of Pharmaceutical and Medicinal Chemistry , Pharmaceutical Institute of the Christian-Albrechts-University of Kiel , 24118 Kiel , Germany
| | - Ulrich Girreser
- Department of Pharmaceutical and Medicinal Chemistry , Pharmaceutical Institute of the Christian-Albrechts-University of Kiel , 24118 Kiel , Germany
| | - Antje Havemeyer
- Department of Pharmaceutical and Medicinal Chemistry , Pharmaceutical Institute of the Christian-Albrechts-University of Kiel , 24118 Kiel , Germany
| | - Florian Bittner
- Federal Research Centre for Cultivated Plants , Julius Kuehn Institute , 06484 Quedlinburg , Germany
| | - Bernd Clement
- Department of Pharmaceutical and Medicinal Chemistry , Pharmaceutical Institute of the Christian-Albrechts-University of Kiel , 24118 Kiel , Germany
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28
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Bender D, Schwarz G. Nitrite-dependent nitric oxide synthesis by molybdenum enzymes. FEBS Lett 2018; 592:2126-2139. [DOI: 10.1002/1873-3468.13089] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 05/02/2018] [Indexed: 01/07/2023]
Affiliation(s)
- Daniel Bender
- Department of Chemistry; Institute for Biochemistry; University of Cologne; Germany
- Center for Molecular Medicine Cologne (CMMC); University of Cologne; Germany
| | - Guenter Schwarz
- Department of Chemistry; Institute for Biochemistry; University of Cologne; Germany
- Center for Molecular Medicine Cologne (CMMC); University of Cologne; Germany
- Cologne Cluster of Excellence in Cellular Stress Responses in Aging-associated Diseases (CECAD); University of Cologne; Germany
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29
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Abdelkawy KS, Lack K, Elbarbry F. Pharmacokinetics and Pharmacodynamics of Promising Arginase Inhibitors. Eur J Drug Metab Pharmacokinet 2018; 42:355-370. [PMID: 27734327 DOI: 10.1007/s13318-016-0381-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Up-regulation of arginase activity in several chronic disease conditions, including cancer and hypertension, may suggest new targets for treatment. Recently, the number of new arginase inhibitors with promising therapeutic effects for asthma, cancer, hypertension, diabetes mellitus, and erectile dysfunction has shown a remarkable increase. Arginase inhibitors may be chemical substances, such as boron-based amino acid derivatives, α-difluoromethylornithine (DMFO), and Nω-hydroxy-nor-L-arginine (nor-NOHA) or, of plant origin such as sauchinone, salvianolic acid B (SAB), piceatannol-3-O-β-D-glucopyranoside (PG) and obacunone. Despite their promising therapeutic potential, little is known about pharmacokinetics and pharmacodynamics of some of these agents. Several studies were conducted in different animal species and in vitro systems and reported significant differences in pharmacokinetics and pharmacodynamics of arginase inhibitors. Therefore, extra caution should be considered before extrapolating these studies to human. Physicochemical and pharmacokinetic profiles of some effective arginase inhibitors make it challenging to formulate stable and effective formulation. In this article, existing literature on the pharmacokinetics and pharmacodynamics of arginase inhibitors were reviewed and compared together with emphasis on possible drug interactions and solutions to overcome pharmacokinetics challenges and shortage of arginase inhibitors in clinical practice.
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Affiliation(s)
| | - Kelsey Lack
- School of Pharmacy, Pacific University, 222 SE 8th Ave., Hillsboro, OR, 97123, USA
| | - Fawzy Elbarbry
- School of Pharmacy, Pacific University, 222 SE 8th Ave., Hillsboro, OR, 97123, USA.
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30
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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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31
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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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Vigani G, Di Silvestre D, Agresta AM, Donnini S, Mauri P, Gehl C, Bittner F, Murgia I. Molybdenum and iron mutually impact their homeostasis in cucumber (Cucumis sativus) plants. THE NEW PHYTOLOGIST 2017; 213:1222-1241. [PMID: 27735062 DOI: 10.1111/nph.14214] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 08/22/2016] [Indexed: 05/22/2023]
Abstract
Molybdenum (Mo) and iron (Fe) are essential micronutrients required for crucial enzyme activities in plant metabolism. Here we investigated the existence of a mutual control of Mo and Fe homeostasis in cucumber (Cucumis sativus). Plants were grown under single or combined Mo and Fe starvation. Physiological parameters were measured, the ionomes of tissues and the ionomes and proteomes of root mitochondria were profiled, and the activities of molybdo-enzymes and the synthesis of molybdenum cofactor (Moco) were evaluated. Fe and Mo were found to affect each other's total uptake and distribution within tissues and at the mitochondrial level, with Fe nutritional status dominating over Mo homeostasis and affecting Mo availability for molybdo-enzymes in the form of Moco. Fe starvation triggered Moco biosynthesis and affected the molybdo-enzymes, with its main impact on nitrate reductase and xanthine dehydrogenase, both being involved in nitrogen assimilation and mobilization, and on the mitochondrial amidoxime reducing component. These results, together with the identification of > 100 proteins differentially expressed in root mitochondria, highlight the central role of mitochondria in the coordination of Fe and Mo homeostasis and allow us to propose the first model of the molecular interactions connecting Mo and Fe homeostasis.
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Affiliation(s)
- Gianpiero Vigani
- Department of Agricultural and Environmental Sciences, University of Milano, via Celoria 2, 20133, Milano, Italy
| | - Dario Di Silvestre
- Proteomic and Metabolomic Laboratory, Institute of Biomedical Technologies, National Research Council (ITB-CNR), via F.lli Cervi 93, 20090, Segrate (MI), Italy
| | - Anna Maria Agresta
- Proteomic and Metabolomic Laboratory, Institute of Biomedical Technologies, National Research Council (ITB-CNR), via F.lli Cervi 93, 20090, Segrate (MI), Italy
| | - Silvia Donnini
- Department of Agricultural and Environmental Sciences, University of Milano, via Celoria 2, 20133, Milano, Italy
| | - Pierluigi Mauri
- Proteomic and Metabolomic Laboratory, Institute of Biomedical Technologies, National Research Council (ITB-CNR), via F.lli Cervi 93, 20090, Segrate (MI), Italy
| | - Christian Gehl
- Institute of Horticulture Production Systems, Leibniz University of Hannover, Herrenhaeuser Str. 2, 30419, Hannover, Germany
| | - Florian Bittner
- Department of Plant Biology, Braunschweig University of Technology, Spielmannstrasse 7, 38106, Braunschweig, Germany
| | - Irene Murgia
- Department of Biosciences, University of Milano, via Celoria 26, 20133, Milano, Italy
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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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Yang J, Giles LJ, Ruppelt C, Mendel RR, Bittner F, Kirk ML. Oxyl and hydroxyl radical transfer in mitochondrial amidoxime reducing component-catalyzed nitrite reduction. J Am Chem Soc 2015; 137:5276-9. [PMID: 25897643 PMCID: PMC4872596 DOI: 10.1021/jacs.5b01112] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A combination of electron paramagnetic resonance (EPR) spectroscopy and computational approaches has provided insight into the nature of the reaction coordinate for the one-electron reduction of nitrite by the mitochondrial amidoxime reducing component (mARC) enzyme. The results show that a paramagnetic Mo(V) species is generated when reduced enzyme is exposed to nitrite, and an analysis of the resulting EPR hyperfine parameters confirms that mARC is remarkably similar to the low-pH form of sulfite oxidase. Two mechanisms for nitrite reduction have been considered. The first shows a modest reaction barrier of 14 kcal/mol for the formation of ·NO from unprotonated nitrite substrate. In marked contrast, protonation of the substrate oxygen proximal to Mo in the Mo(IV)-O-N-O substrate-bound species results in barrierless conversion to products. A fragment orbital analysis reveals a high degree of Mo-O(H)-N-O covalency that provides a π-orbital pathway for one-electron transfer to the substrate and defines orbital constraints on the Mo-substrate geometry for productive catalysis in mARC and other pyranopterin molybdenum enzymes that catalyze this one-electron transformation.
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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
| | - Logan J. Giles
- Department of Chemistry and Chemical Biology, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, NM 87131-0001
| | - Christian Ruppelt
- Department of Plant Biology, Braunschweig University of Technology, Humboldtstrasse 1, 38023 Braunschweig, Germany
| | - Ralf R. Mendel
- Department of Plant Biology, Braunschweig University of Technology, Humboldtstrasse 1, 38023 Braunschweig, Germany
| | - Florian Bittner
- Department of Plant Biology, Braunschweig University of Technology, Humboldtstrasse 1, 38023 Braunschweig, 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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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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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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Giles LJ, Ruppelt C, Yang J, Mendel RR, Bittner F, Kirk ML. Molybdenum site structure of MOSC family proteins. Inorg Chem 2014; 53:9460-2. [PMID: 25166909 PMCID: PMC4164224 DOI: 10.1021/ic5015863] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Mo K-edge X-ray absorption spectroscopy has been used to probe as-isolated structures of the MOSC family proteins pmARC-1 and HMCS-CT. The Mo K-edge near-edge spectrum of HMCS-CT is shifted ~2.5 eV to lower energy compared to the pmARC-1 spectrum, which indicates that as-isolated HMCS-CT is in a more reduced state than pmARC-1. Extended X-ray absorption fine structure analysis indicates significant structural differences between pmARC-1 and HMCS-CT, with the former being a dioxo site and the latter possessing only a single terminal oxo ligand. The number of terminal oxo donors is consistent with pmARC-1 being in the Mo(VI) oxidation state and HMCS-CT in the Mo(IV) state. These structures are in accord with oxygen-atom-transfer reactivity for pmARC-1 and persulfide bond cleavage chemistry for HMCS-CT.
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Affiliation(s)
- Logan J Giles
- Department of Chemistry and Chemical Biology, The University of New Mexico , MSC03 2060, 1 University of New Mexico, Albuquerque, New Mexico 87131-0001, United States
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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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Tejada-Jiménez M, Schwarz G. Molybdenum and Tungsten. BINDING, TRANSPORT AND STORAGE OF METAL IONS IN BIOLOGICAL CELLS 2014. [DOI: 10.1039/9781849739979-00223] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Molybdenum (Mo) is an essential micronutrient for the majority of organisms ranging from bacteria to animals. To fulfil its biological role, it is incorporated into a pterin-based Mo-cofactor (Moco) and can be found in the active centre of more than 50 enzymes that are involved in key reactions of carbon, nitrogen and sulfur metabolism. Five of the Mo-enzymes are present in eukaryotes: nitrate reductase (NR), sulfite oxidase (SO), aldehyde oxidase (AO), xanthine oxidase (XO) and the amidoxime-reducing component (mARC). Cells acquire Mo in form of the oxyanion molybdate using specific molybdate transporters. In bacteria, molybdate transport is an extensively studied process and is mediated mainly by the ATP-binding cassette system ModABC. In contrast, in eukaryotes, molybdate transport is poorly understood since specific molybdate transporters remained unknown until recently. Two rather distantly related families of proteins, MOT1 and MOT2, are involved in eukaryotic molybdate transport. They each feature high-affinity molybdate transporters that regulate the intracellular concentration of Mo and thus control activity of Mo-enzymes. The present chapter presents an overview of the biological functions of Mo with special focus on recent data related to its uptake, binding and storage.
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Affiliation(s)
- Manuel Tejada-Jiménez
- Institute of Biochemistry, Department of Chemistry, University of Cologne Zuelpicher Str. 47 Cologne 50674 Germany
| | - Guenter Schwarz
- Institute of Biochemistry, Department of Chemistry, University of Cologne Zuelpicher Str. 47 Cologne 50674 Germany
- Center for Molecular Medicine Cologne, University of Cologne Robert-Koch Str. 21 Cologne 50931 Germany
- Cluster of Excellence in Ageing Research, CECAD Research Center Joseph-Stelzmann-Str. 26 Cologne 50931 Germany
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Mitochondrial proteomic analysis reveals the molecular mechanisms underlying reproductive toxicity of zearalenone in MLTC-1 cells. Toxicology 2014; 324:55-67. [PMID: 25058043 DOI: 10.1016/j.tox.2014.07.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 07/03/2014] [Accepted: 07/18/2014] [Indexed: 02/07/2023]
Abstract
Zearalenone (ZEA), a Fusarium mycotoxin that contaminates cereal crops worldwide, has been shown to affect the male reproductive system and trigger reactive oxygen species (ROS) generation. However, the mechanisms of its toxicity have not been fully understood. Because mitochondrion is a key organelle involved in producing ROS and generating metabolic intermediates for biosynthesis, an iTRAQ-based mitoproteomics approach was employed to identify the molecular mechanism of zearalenone toxicity using mitochondria of mouse Leydig tumor cells (MLTC-1). A total of 2014 nonredundant proteins were identified, among which 1401 proteins (69.56%) were overlapped. There were 52 differentially expressed proteins in response to ZEA, and they were primarily involved in energy metabolism, molecular transport and endocrine-related functions. Consistent with mitochondrial proteomic analysis, the ATP and intracellular Ca(2+) levels increased after ZEA treatment. The results suggest that lipid metabolism changed significantly after low-dose ZEA exposure, resulting in two alterations. One is the increase in energy production through promoted fatty acid uptake and β-oxidation, along with excessive oxidative stress; the other is an inhibition of steroidogenesis and esterification, possibly resulting in reduced hormone secretion. A hypothetical model of ZEA-induced mitochondrial damage is proposed to provide a framework for the mechanism of ZEA toxicity.
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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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Abstract
Molybdenum is an essential trace element and crucial for the survival of animals. Four mammalian Mo-dependent enzymes are known, all of them harboring a pterin-based molybdenum cofactor (Moco) in their active site. In these enzymes, molybdenum catalyzes oxygen transfer reactions from or to substrates using water as oxygen donor or acceptor. Molybdenum shuttles between two oxidation states, Mo(IV) and Mo(VI). Following substrate reduction or oxidation, electrons are subsequently shuttled by either inter- or intra-molecular electron transfer chains involving prosthetic groups such as heme or iron-sulfur clusters. In all organisms studied so far, Moco is synthesized by a highly conserved multi-step biosynthetic pathway. A deficiency in the biosynthesis of Moco results in a pleitropic loss of all four human Mo-enzyme activities and in most cases in early childhood death. In this review we first introduce general aspects of molybdenum biochemistry before we focus on the functions and deficiencies of two Mo-enzymes, xanthine dehydrogenase and sulfite oxidase, caused either by deficiency of the apo-protein or a pleiotropic loss of Moco due to a genetic defect in its biosynthesis. The underlying molecular basis of Moco deficiency, possible treatment options and links to other diseases, such as neuropsychiatric disorders, will be discussed.
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Affiliation(s)
- Guenter Schwarz
- Institute of Biochemistry, Department of Chemistry, Center for Molecular Medicine, University of Cologne, Zülpicher Strasse 47, D-50674, Köln, Germany,
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Affiliation(s)
- Russ Hille
- Department of Biochemistry, University of California, Riverside, Riverside, California 92521, United States
| | - James Hall
- Department of Biochemistry, University of California, Riverside, Riverside, California 92521, United States
| | - Partha Basu
- Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, Pennsylvania 15282, United States
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Sparacino-Watkins CE, Tejero J, Sun B, Gauthier MC, Thomas J, Ragireddy V, Merchant BA, Wang J, Azarov I, Basu P, Gladwin MT. Nitrite reductase and nitric-oxide synthase activity of the mitochondrial molybdopterin enzymes mARC1 and mARC2. J Biol Chem 2014; 289:10345-10358. [PMID: 24500710 DOI: 10.1074/jbc.m114.555177] [Citation(s) in RCA: 111] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Mitochondrial amidoxime reducing component (mARC) proteins are molybdopterin-containing enzymes of unclear physiological function. Both human isoforms mARC-1 and mARC-2 are able to catalyze the reduction of nitrite when they are in the reduced form. Moreover, our results indicate that mARC can generate nitric oxide (NO) from nitrite when forming an electron transfer chain with NADH, cytochrome b5, and NADH-dependent cytochrome b5 reductase. The rate of NO formation increases almost 3-fold when pH was lowered from 7.5 to 6.5. To determine if nitrite reduction is catalyzed by molybdenum in the active site of mARC-1, we mutated the putative active site cysteine residue (Cys-273), known to coordinate molybdenum binding. NO formation was abolished by the C273A mutation in mARC-1. Supplementation of transformed Escherichia coli with tungsten facilitated the replacement of molybdenum in recombinant mARC-1 and abolished NO formation. Therefore, we conclude that human mARC-1 and mARC-2 are capable of catalyzing reduction of nitrite to NO through reaction with its molybdenum cofactor. Finally, expression of mARC-1 in HEK cells using a lentivirus vector was used to confirm cellular nitrite reduction to NO. A comparison of NO formation profiles between mARC and xanthine oxidase reveals similar Kcat and Vmax values but more sustained NO formation from mARC, possibly because it is not vulnerable to autoinhibition via molybdenum desulfuration. The reduction of nitrite by mARC in the mitochondria may represent a new signaling pathway for NADH-dependent hypoxic NO production.
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Affiliation(s)
- Courtney E Sparacino-Watkins
- Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania 15261; Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15213
| | - Jesús Tejero
- Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania 15261
| | - Bin Sun
- Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania 15261; Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15213
| | - Marc C Gauthier
- Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania 15261; Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15213
| | - John Thomas
- Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, Pennsylvania 15282
| | - Venkata Ragireddy
- Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania 15261
| | - Bonnie A Merchant
- Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania 15261
| | - Jun Wang
- Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania 15261
| | - Ivan Azarov
- Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania 15261
| | - Partha Basu
- Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, Pennsylvania 15282
| | - Mark T Gladwin
- Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania 15261; Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15213.
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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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Bittner F. Molybdenum metabolism in plants and crosstalk to iron. FRONTIERS IN PLANT SCIENCE 2014; 5:28. [PMID: 24570679 PMCID: PMC3916724 DOI: 10.3389/fpls.2014.00028] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Accepted: 01/22/2014] [Indexed: 05/04/2023]
Abstract
In the form of molybdate the transition metal molybdenum is essential for plants as it is required by a number of enzymes that catalyze key reactions in nitrogen assimilation, purine degradation, phytohormone synthesis, and sulfite detoxification. However, molybdate itself is biologically inactive and needs to be complexed by a specific organic pterin in order to serve as a permanently bound prosthetic group, the molybdenum cofactor, for the socalled molybdo-enyzmes. While the synthesis of molybdenum cofactor has been intensively studied, only little is known about the uptake of molybdate by the roots, its transport to the shoot and its allocation and storage within the cell. Yet, recent evidence indicates that intracellular molybdate levels are tightly controlled by molybdate transporters, in particular during plant development. Moreover, a tight connection between molybdenum and iron metabolisms is presumed because (i) uptake mechanisms for molybdate and iron affect each other, (ii) most molybdo-enzymes do also require iron-containing redox groups such as iron-sulfur clusters or heme, (iii) molybdenum metabolism has recruited mechanisms typical for iron-sulfur cluster synthesis, and (iv) both molybdenum cofactor synthesis and extramitochondrial iron-sulfur proteins involve the function of a specific mitochondrial ABC-type transporter.
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Affiliation(s)
- Florian Bittner
- *Correspondence: Florian Bittner, Department of Plant Biology, Braunschweig University of Technology, Spielmannstrasse 7, 38106 Braunschweig, Germany e-mail:
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Wood PL. Mass spectrometry strategies for clinical metabolomics and lipidomics in psychiatry, neurology, and neuro-oncology. Neuropsychopharmacology 2014; 39:24-33. [PMID: 23842599 PMCID: PMC3857645 DOI: 10.1038/npp.2013.167] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 07/04/2013] [Indexed: 12/14/2022]
Abstract
Metabolomics research has the potential to provide biomarkers for the detection of disease, for subtyping complex disease populations, for monitoring disease progression and therapy, and for defining new molecular targets for therapeutic intervention. These potentials are far from being realized because of a number of technical, conceptual, financial, and bioinformatics issues. Mass spectrometry provides analytical platforms that address the technical barriers to success in metabolomics research; however, the limited commercial availability of analytical and stable isotope standards has created a bottleneck for the absolute quantitation of a number of metabolites. Conceptual and financial factors contribute to the generation of statistically under-powered clinical studies, whereas bioinformatics issues result in the publication of a large number of unidentified metabolites. The path forward in this field involves targeted metabolomics analyses of large control and patient populations to define both the normal range of a defined metabolite and the potential heterogeneity (eg, bimodal) in complex patient populations. This approach requires that metabolomics research groups, in addition to developing a number of analytical platforms, build sufficient chemistry resources to supply the analytical standards required for absolute metabolite quantitation. Examples of metabolomics evaluations of sulfur amino-acid metabolism in psychiatry, neurology, and neuro-oncology and of lipidomics in neurology will be reviewed.
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Affiliation(s)
- Paul L Wood
- Metabolomics Unit, Department of Physiology and Pharmacology, DeBusk College of Osteopathic Medicine, Lincoln Memorial University, Math and Science 435, Harrogate, TN 37752, USA
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