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Lee W, Kim MS, Kim J, Aoki Y, Sugiyama Y. Predicting In Vivo Target Occupancy (TO) Profiles via Physiologically Based Pharmacokinetic-TO Modeling of Warfarin Pharmacokinetics in Blood: Importance of Low Dose Data and Prediction of Stereoselective Target Interactions. Drug Metab Dispos 2023; 51:1145-1156. [PMID: 36914276 DOI: 10.1124/dmd.122.000968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 02/09/2023] [Accepted: 03/09/2023] [Indexed: 03/14/2023] Open
Abstract
Warfarin is well recognized for its high-affinity and capacity-limited binding to the pharmacological target and undergoes target-mediated drug disposition. Here, we developed a physiologically based pharmacokinetic (PBPK) model that incorporated saturable target binding and other reported hepatic disposition components of warfarin. The PBPK model parameters were optimized by fitting to the reported blood pharmacokinetic (PK) profiles of warfarin with no stereoisomeric separation after oral dosing of racemic warfarin (0.1, 2, 5, or 10 mg) using the Cluster Gauss-Newton method (CGNM). The CGNM-based analysis yielded multiple "accepted" sets for six optimized parameters, which were then used to simulate the warfarin blood PK and in vivo target occupancy (TO) profiles. When further analyses examined the impact of dose selection on uncertainty in parameter estimation by the PBPK modeling, the PK data from 0.1 mg dose (well below target saturation) was important in practically identifying the target binding-related parameters in vivo. When stereoselective differences were incorporated for both hepatic disposition and target interactions, our PBPK modeling predicted that R-warfarin (of slower clearance and lower target affinity than S-warfarin) contributes to TO prolongation after oral dosing of racemic warfarin. Our results extend the validity of the approach by which the PBPK-TO modeling of blood PK profiles can yield TO prediction in vivo (applicable to the drugs with targets of high affinity and abundance and limited distribution volume via nontarget interactions). Our findings support that model-informed dose selection and PBPK-TO modeling may aid in TO and efficacy assessment in preclinical and clinical phase 1 studies. SIGNIFICANCE STATEMENT: The current physiologically based pharmacokinetic modeling incorporated the reported hepatic disposition components and target binding of warfarin and analyzed the blood pharmacokinetic (PK) profiles from varying warfarin doses, practically identifying target binding-related parameters in vivo. By implementing the stereoselective differences between R- and S-warfarin, our analysis predicted the role of R-warfarin in prolonging overall target occupancy. Our results extend the validity of analyzing blood PK profiles to predict target occupancy in vivo, which may guide efficacy assessment.
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Affiliation(s)
- Wooin Lee
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Korea (W.L., M-S.K., J.K.); Laboratory of Quantitative System Pharmacokinetics/Pharmacodynamics, Josai International University, Tokyo, Japan (Y.A., Y.S.); and Drug Metabolism and Pharmacokinetics, Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden (Y.A.)
| | - Min-Soo Kim
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Korea (W.L., M-S.K., J.K.); Laboratory of Quantitative System Pharmacokinetics/Pharmacodynamics, Josai International University, Tokyo, Japan (Y.A., Y.S.); and Drug Metabolism and Pharmacokinetics, Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden (Y.A.)
| | - Jiyoung Kim
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Korea (W.L., M-S.K., J.K.); Laboratory of Quantitative System Pharmacokinetics/Pharmacodynamics, Josai International University, Tokyo, Japan (Y.A., Y.S.); and Drug Metabolism and Pharmacokinetics, Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden (Y.A.)
| | - Yasunori Aoki
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Korea (W.L., M-S.K., J.K.); Laboratory of Quantitative System Pharmacokinetics/Pharmacodynamics, Josai International University, Tokyo, Japan (Y.A., Y.S.); and Drug Metabolism and Pharmacokinetics, Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden (Y.A.)
| | - Yuichi Sugiyama
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Korea (W.L., M-S.K., J.K.); Laboratory of Quantitative System Pharmacokinetics/Pharmacodynamics, Josai International University, Tokyo, Japan (Y.A., Y.S.); and Drug Metabolism and Pharmacokinetics, Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden (Y.A.)
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2
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Liu S, Shen G, Li W. Structural and cellular basis of vitamin K antagonism. J Thromb Haemost 2022; 20:1971-1983. [PMID: 35748323 DOI: 10.1111/jth.15800] [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: 05/02/2022] [Revised: 06/15/2022] [Accepted: 06/20/2022] [Indexed: 11/30/2022]
Abstract
Vitamin K antagonists (VKAs), such as warfarin, are oral anticoagulants widely used to treat and prevent thromboembolic diseases. Therapeutic use of these drugs requires frequent monitoring and dose adjustments, whereas overdose often causes severe bleeding. Addressing these drawbacks requires mechanistic understandings at cellular and structural levels. As the target of VKAs, vitamin K epoxide reductase (VKOR) generates the active, hydroquinone form of vitamin K, which in turn drives the γ-carboxylation of several coagulation factors required for their activity. Crystal structures revealed that VKAs inhibit VKOR via mimicking its catalytic process. At the active site, two strong hydrogen bonds that facilitate the catalysis also afford the binding specificity for VKAs. Binding of VKAs induces a global change from open to closed conformation. Similar conformational change is induced by substrate binding to promote an electron transfer process that reduces the VKOR active site. In the cellular environment, reducing partner proteins or small reducing molecules may afford electrons to maintain the VKOR activity. The catalysis and VKA inhibition require VKOR in different cellular redox states, explaining the complex kinetics behavior of VKAs. Recent studies also revealed the mechanisms underlying warfarin resistance, warfarin dose variation, and antidoting by vitamin K. These mechanistic understandings may lead to improved anticoagulation strategies targeting the vitamin K cycle.
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Affiliation(s)
- Shixuan Liu
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Guomin Shen
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
- Henan International Joint Laboratory of Thrombosis and Hemostasis, School of Basic Medical Science, Henan University of Science and Technology, Luoyang, China
- Department of Cell Biology, Harbin Medical University, Harbin, China
| | - Weikai Li
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
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3
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Li J, Li J, Wang G, Ho KF, Han J, Dai W, Wu C, Cao C, Liu L. In-vitro oxidative potential and inflammatory response of ambient PM 2.5 in a rural region of Northwest China: Association with chemical compositions and source contribution. ENVIRONMENTAL RESEARCH 2022; 205:112466. [PMID: 34863982 DOI: 10.1016/j.envres.2021.112466] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 11/15/2021] [Accepted: 11/27/2021] [Indexed: 06/13/2023]
Abstract
Overproduction of reactive oxygen species (ROS) induced by atmospheric particles and subsequent inflammatory responses are considered as one of the most important pathological mechanisms with regard to the adverse effects of air pollution exposure. In this study, fine particulate matter (PM2.5) samples were collected at a rural site in Guanzhong Basin, Northwest China, in both summer (August 3-23, 2016) and winter (January 5-February 1, 2017). Then, human bronchial epithelial BEAS-2B cells were exposed to the PM2.5, cultured for 24 h, and then assayed for particle-induced ROS and three inflammatory factors (tumor necrosis-α (TNF-α), interleukin-6 (IL-6), and interferon-γ (IFN-γ)) in vitro. The oxidative potential (OP) induced by winter PM2.5 samples was higher than that induced by summertime samples, whereas inflammatory values showed contrasting seasonal variations. Both OP and inflammatory factors were significantly correlated with most chemical compounds in winter, but not in summer, which was thought to be related mainly to the higher contribution from secondary aerosols formed during the warm season. Source apportionment results showed secondary aerosols formation have significant contribution to OP of PM2.5 in both seasons, but the dominant oxidation processes is different. Secondary nitrates-related process was the major contributors regulating the OP in winter; however, secondary sulfates formation were mainly responsible for the ROS responses in summer. For primary emission, biomass burning, rather than coal emission or vehicle exhaust, was the significant source for OP of PM2.5 in winter. In most cases, the source contribution of each inflammatory factor was similar to that of the ROS. Our results highlighted the significant health risk of atmospheric aerosols from biomass burning in the rural regions of Guanzhong Basin, Northwest China.
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Affiliation(s)
- Jianjun Li
- Key Lab of Aerosol Chemistry & Physics, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China; CAS Center for Excellence in Quaternary Science and Global Change, Xi'an, 710061, China.
| | - Jin Li
- Key Lab of Aerosol Chemistry & Physics, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China
| | - Gehui Wang
- Key Laboratory of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai, 200241, China; Institute of Eco-Chongming, 3663 N. Zhongshan Rd., Shanghai, 200062, China.
| | - Kin Fai Ho
- The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China; Shenzhen Municipal Key Laboratory for Health Risk Analysis, Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, China
| | - Jing Han
- College of Public Health, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, China
| | - Wenting Dai
- Key Lab of Aerosol Chemistry & Physics, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China
| | - Can Wu
- Key Laboratory of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai, 200241, China; Institute of Eco-Chongming, 3663 N. Zhongshan Rd., Shanghai, 200062, China
| | - Cong Cao
- Key Lab of Aerosol Chemistry & Physics, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China
| | - Lang Liu
- Key Lab of Aerosol Chemistry & Physics, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China
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Feng X, Shao L, Jones T, Li Y, Cao Y, Zhang M, Ge S, Yang CX, Lu J, BéruBé K. Oxidative potential and water-soluble heavy metals of size-segregated airborne particles in haze and non-haze episodes: Impact of the "Comprehensive Action Plan" in China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 814:152774. [PMID: 34986423 DOI: 10.1016/j.scitotenv.2021.152774] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 12/14/2021] [Accepted: 12/25/2021] [Indexed: 05/17/2023]
Abstract
Air pollution is a major environmental health challenge in megacities, and as such a Comprehensive Action Plan (CAP) was issued in 2017 for Beijing, the capital city of China. Here we investigated the size-segregated airborne particles collected after the implementation of the CAP, intending to understand the change of oxidative potential and water-soluble heavy metal (WSHM) levels in 'haze' and 'non-haze' days. The DNA damage and the levels of WSHM were analyzed by Plasmid Scission Assay (PSA) and High-Resolution Inductively Coupled Plasma Mass Spectrometry (HR-ICP-MS) techniques. The PM mass concentration was higher in the fine particle size (0.43-2.1 μm) during haze days, except for the samples affected by mineral dust. The particle-induced DNA damage caused by fine sized particles (0.43-2.1 μm) exceeded that caused by the coarse sized particles (4.7-10 μm). The DNA damage from haze day particles significantly exceeded those collected on non-haze days. Prior to the instigation of the CAP, the highest value of DNA damage decreased, and DNA damage was seen in the finer size (0.43-1.1 μm). The Pearson correlation coefficient between the concentrations of water-soluble Pb, Cr, Cd and Zn were positively correlated with DNA damage, suggesting that these WSHM had significant oxidative potential. The mass concentrations of water-soluble trace elements (WSTE) and individual heavy metals were enriched in the finer particles between 0.43 μm to 1.1 μm, implying that smaller sized particles posed higher health risks. In contrast, the significant reduction in the mass concentration of water-soluble Cd and Zn, and the decrease of the maximum and average values of DNA damage after the CAP, demonstrated its effectiveness in restricting coal-burning emissions. These results have demonstrated that the Beijing CAP policy has been successful in reducing the toxicity of 'respirable' ambient particles.
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Affiliation(s)
- Xiaolei Feng
- State Key Laboratory of Coal Resources and Safe Mining, and College of Geoscience and Surveying Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China
| | - Longyi Shao
- State Key Laboratory of Coal Resources and Safe Mining, and College of Geoscience and Surveying Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China.
| | - Tim Jones
- School of Earth and Environmental Sciences, Cardiff University, Park Place, Cardiff CF10 3AT, Wales, UK
| | - Yaowei Li
- State Key Laboratory of Coal Resources and Safe Mining, and College of Geoscience and Surveying Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China
| | - Yaxin Cao
- State Key Laboratory of Coal Resources and Safe Mining, and College of Geoscience and Surveying Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China
| | - Mengyuan Zhang
- State Key Laboratory of Coal Resources and Safe Mining, and College of Geoscience and Surveying Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China
| | - Shuoyi Ge
- State Key Laboratory of Coal Resources and Safe Mining, and College of Geoscience and Surveying Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China
| | - Cheng-Xue Yang
- Institute of Earth Sciences, China University of Geosciences (Beijing), Beijing 100083, China
| | - Jing Lu
- State Key Laboratory of Coal Resources and Safe Mining, and College of Geoscience and Surveying Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China
| | - Kelly BéruBé
- School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3AX, Wales, UK
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5
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Pes K, Ortiz-Delgado JB, Sarasquete C, Laizé V, Fernández I. Short-term exposure to pharmaceuticals negatively impacts marine flatfish species: Histological, biochemical and molecular clues for an integrated ecosystem risk assessment. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2022; 90:103822. [PMID: 35101594 DOI: 10.1016/j.etap.2022.103822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 01/24/2022] [Accepted: 01/26/2022] [Indexed: 06/14/2023]
Abstract
The marine habitat and its biodiversity can be impacted by released pharmaceuticals. The short-term (7 days) effect of 3 commonly used drugs - warfarin, dexamethasone and imidazole - on Senegalese sole (Solea senegalensis) juveniles was investigated. Occurrence of hemorrhages, histopathological alterations, antioxidant status, activity of antioxidant enzymes and expression of genes involved in the xenobiotic response (pxr, abcb1 and cyp1a), were evaluated. The results showed a time and drug-dependent effect. Warfarin exposure induced hemorrhages, hepatocyte vacuolar degeneration, and altered the activity of glutathione peroxidase (GPx) and the expression of all the studied genes. Dexamethasone exposure increased liver glycogen content, altered antioxidant status, GPx and superoxide dismutase activities, as well as abcb1 and cyp1a expression. Imidazole induced hepatocyte vacuolar degeneration and ballooning, and altered the antioxidant status and expression of the tested genes. The present work anticipates a deeper impact of pharmaceuticals on the aquatic environment than previously reported, thus underlining the urgent need for an integrated risk assessment.
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Affiliation(s)
- Katia Pes
- Centro de Ciências do Mar (CCMAR), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
| | - Juan B Ortiz-Delgado
- Instituto de Ciencias Marinas de Andalucía-ICMAN/CSIC, Campus Universitario Río San Pedro, Apdo. Oficial, 11510 Puerto Real, Cádiz, Spain
| | - Carmen Sarasquete
- Instituto de Ciencias Marinas de Andalucía-ICMAN/CSIC, Campus Universitario Río San Pedro, Apdo. Oficial, 11510 Puerto Real, Cádiz, Spain
| | - Vincent Laizé
- Centro de Ciências do Mar (CCMAR), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal; S2 AQUA - Sustainable and Smart Aquaculture Collaborative Laboratory, Olhão, Portugal
| | - Ignacio Fernández
- Aquaculture Research Center, Agro-Technological Institute of Castilla y León (ITACyL), Ctra. Arévalo, s/n, 40196 Zamarramala, Segovia, Spain; Centro Oceanográfico de Vigo, Instituto Español de Oceanografía (IEO-CSIC), 36390 Vigo, Spain.
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6
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Liu S, Li S, Krezel AM, Li W. Stabilization and structure determination of integral membrane proteins by termini restraining. Nat Protoc 2022; 17:540-565. [PMID: 35039670 DOI: 10.1038/s41596-021-00656-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 11/05/2021] [Indexed: 12/28/2022]
Abstract
Integral membrane proteins isolated from cellular environment often lose activity and native conformation required for functional analyses and structural studies. Even in their native state, they lack sufficient surfaces to form crystal contacts. Furthermore, most of them are too small for cryogenic electron microscopy detection and too big for solution NMR. To overcome these difficulties, we recently developed a strategy to stabilize the folded state of membrane proteins by restraining their two termini with a self-assembling protein coupler. The termini-restrained membrane proteins from distinct functional families retain their activities and show increased stability and yield. This strategy enables their structure determination at near-atomic resolution by facilitating the entire pipeline from crystallization, crystal identification, diffraction enhancement and phase determination, to electron density improvement. Furthermore, stabilization of membrane proteins enables their biochemical and biophysical characterization. Here we present the protocol of membrane protein engineering (2 weeks), quality assessment (1-2 weeks), protein production (1-6 weeks), crystallization (1-2 weeks), diffraction improvement (1-3 months) and crystallographic data analysis (1 week). This protocol is intended not only for structural biologists, but also for biochemists, biophysicists and pharmaceutical scientists whose research focuses on membrane proteins.
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Affiliation(s)
- Shixuan Liu
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA
| | - Shuang Li
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA
| | - Andrzej M Krezel
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA
| | - Weikai Li
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA.
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7
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Chetot T, Benoit E, Lambert V, Lattard V. Overexpression of protein disulfide isomerase enhances vitamin K epoxide reductase activity. Biochem Cell Biol 2022; 100:152-161. [PMID: 35007172 DOI: 10.1139/bcb-2021-0441] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Vitamin K epoxide reductase (VKOR) activity is catalyzed by the VKORC1 enzyme. It is the target of vitamin K antagonists (VKA). Numerous mutations of VKORC1 have been reported and have been suspected to confer resistance to VKA and/or affect its velocity. Nevertheless, the results between studies have been conflicting, the functional characterization of these mutations in a cell system being complex due to the interweaving of VKOR activity in the vitamin K cycle. In this study, a new cellular approach was implemented to globally evaluate the vitamin K cycle in the HEK293 cells. This global approach was based on the vitamin K quinone/vitamin K epoxide (K/KO) balance. In the presence of VKA or when the VKORC1/VKORC1L1 were knocked out, the K/KO balance decreased significantly due to an accumulation of vitamin KO. On the contrary, when VKORC1 was overexpressed, the balance remained unchanged, demonstrating a limitation of the VKOR activity. This limitation was shown to be due to an insufficient expression of the activation partner of VKORC1, as overexpressing the protein disulfide isomerase (PDI) overcomes the limitation. This study is the first to demonstrate a functional interaction between VKORC1 and the PDI enzyme.
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Affiliation(s)
| | | | | | - Virginie Lattard
- VetAgro Sup, 88622, USC1233 INRAe-VetAgroSup, Marcy-l'Etoile, France, 69280;
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8
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Pes K, Friese A, Cox CJ, Laizé V, Fernández I. Biochemical and molecular responses of the Mediterranean mussel (Mytilus galloprovincialis) to short-term exposure to three commonly prescribed drugs. MARINE ENVIRONMENTAL RESEARCH 2021; 168:105309. [PMID: 33798995 DOI: 10.1016/j.marenvres.2021.105309] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 03/03/2021] [Accepted: 03/11/2021] [Indexed: 06/12/2023]
Abstract
Pharmaceuticals represent a group of emerging contaminants. The short-term effect (3 and 7 days) of warfarin (1 and 10 mg L-1), dexamethasone (0.392 and 3.92 mg L-1) and imidazole (0.013 and 0.13 mg L-1) exposure was evaluated on mussels (Mytilus galloprovincialis). Total antioxidant status, glutathione reductase, glutathione peroxidase (GPx) and superoxide dismutase enzyme activities, and the expression of genes involved in the xenobiotic response (ATP binding cassette subfamily B member 1 (abcb1) and several nuclear receptor family J (nr1j) isoforms), were evaluated. All nr1j isoforms are suggested to be the xenobiotic receptor orthologs of the NR1I family. All drugs increased GPx activity and altered the expression of particular nr1j isoforms. Dexamethasone exposure also decreased abcb1 expression. These findings raised some concerns regarding the release of these pharmaceuticals into the aquatic environment. Thus, further studies might be needed to perform an accurate environmental risk assessment of these 3 poorly studied drugs.
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Affiliation(s)
- Katia Pes
- Centro de Ciências do Mar (CCMAR), Universidade do Algarve, Campus de Gambelas, 8005-139, Faro, Portugal
| | - Annika Friese
- Centro de Ciências do Mar (CCMAR), Universidade do Algarve, Campus de Gambelas, 8005-139, Faro, Portugal
| | - Cymon J Cox
- Centro de Ciências do Mar (CCMAR), Universidade do Algarve, Campus de Gambelas, 8005-139, Faro, Portugal
| | - Vincent Laizé
- Centro de Ciências do Mar (CCMAR), Universidade do Algarve, Campus de Gambelas, 8005-139, Faro, Portugal
| | - Ignacio Fernández
- Aquaculture Research Center, Agro-Technological Institute of Castilla y León (ITACyL), Ctra. Arévalo, s/n. 40196 Zamarramala, Segovia, Spain.
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9
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Competitive tight-binding inhibition of VKORC1 underlies warfarin dosage variation and antidotal efficacy. Blood Adv 2021; 4:2202-2212. [PMID: 32433747 DOI: 10.1182/bloodadvances.2020001750] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 04/24/2020] [Indexed: 11/20/2022] Open
Abstract
Dose control of warfarin is a major complication in anticoagulation therapy and overdose is reversed by the vitamin K antidote. Improving the dosage management and antidotal efficacy requires mechanistic understanding. Here we find that effects of the major predictor of warfarin dosage, SNP -1639 G>A, follow a general correlation that warfarin 50% inhibitory concentration decreases with cellular level of vitamin K epoxide reductase (VKORC1), suggesting stoichiometric inhibition. Characterization of the inhibition kinetics required the use of microsomal VKORC1 with a native reductant, glutathione, that enables effective warfarin inhibition in vitro. The kinetics data can be fitted with the Morrison equation, giving a nanomolar inhibition constant and demonstrating that warfarin is a tight-binding inhibitor. However, warfarin is released from purified VKORC1-warfarin complex with increasing amount of vitamin K, indicating competitive inhibition. The competition occurs also in cells, resulting in rescued VKORC1 activity that augments the antidotal effects of vitamin K. Taken together, warfarin is a competitive inhibitor that binds VKORC1 tightly and inhibits at a stoichiometric (1:1) concentration, whereas exceeding the VKORC1 level results in warfarin overdose. Thus, warfarin dosage control should use VKORC1 level as a major indicator, and improved antidotes may be designed based on their competition with warfarin.
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10
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Li J, Li J, Wang G, Ho KF, Dai W, Zhang T, Wang Q, Wu C, Li L, Li L, Zhang Q. Effects of atmospheric aging processes on in vitro induced oxidative stress and chemical composition of biomass burning aerosols. JOURNAL OF HAZARDOUS MATERIALS 2021; 401:123750. [PMID: 33113732 DOI: 10.1016/j.jhazmat.2020.123750] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Revised: 07/30/2020] [Accepted: 08/15/2020] [Indexed: 06/11/2023]
Abstract
Biomass burning (BB) has an important impact on local/regional air quality and human health in China, but most previous studies overlooked the influence of atmospheric aging processes on cytotoxicity and chemical composition of BB aerosols. In this study, we combined a combustion chamber and an oxidation flow reactor to generate fresh and aged BB PM2.5. Human bronchial epithelial BEAS-2B cells were exposed to PM2.5 preparation for 24 h, and then determined for particle-induced reactive oxygen species (ROS) in vitro. The particle-induced ROS production increased by 11 %-64 % after two days of aging, suggesting an enhancement of in vitro-induced oxidative stress (OS) of aged BB particles. Chemical analysis showed that organic matter (OM) was the dominant component with no changes in relative abundance for the fresh and aged BB particles. Organic polycyclic aromatic compounds and some metals showed strong correlations with ROS in fresh particles, indicating the important effects of these harmful components on the OS of fresh BB aerosols. However, such correlations were not found for the aged particles, which is possibly related to the loss of non- or low-toxic semivolatile compounds and the formation of secondary harmful OM (such as some N-containing organic compounds) during the atmospheric aging processes.
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Affiliation(s)
- Jianjun Li
- Key Lab of Aerosol Chemistry & Physics, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China.
| | - Jin Li
- Key Lab of Aerosol Chemistry & Physics, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China
| | - Gehui Wang
- Key Laboratory of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai, 200241, China; Institute of Eco-Chongming, 3663 N. Zhongshan Rd., Shanghai, 200062, China.
| | - Kin Fai Ho
- The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China; Shenzhen Municipal Key Laboratory for Health Risk Analysis, Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, China
| | - Wenting Dai
- Key Lab of Aerosol Chemistry & Physics, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China
| | - Ting Zhang
- Key Lab of Aerosol Chemistry & Physics, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China
| | - Qiyuan Wang
- Key Lab of Aerosol Chemistry & Physics, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China
| | - Can Wu
- Key Laboratory of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai, 200241, China; Institute of Eco-Chongming, 3663 N. Zhongshan Rd., Shanghai, 200062, China
| | - Lijuan Li
- Key Lab of Aerosol Chemistry & Physics, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China; Department of Environmental Toxicology, University of California, Davis, CA 95616, USA
| | - Li Li
- Key Lab of Aerosol Chemistry & Physics, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China
| | - Qi Zhang
- Department of Environmental Toxicology, University of California, Davis, CA 95616, USA
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11
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Liu S, Li S, Shen G, Sukumar N, Krezel AM, Li W. Structural basis of antagonizing the vitamin K catalytic cycle for anticoagulation. Science 2020; 371:science.abc5667. [PMID: 33154105 DOI: 10.1126/science.abc5667] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Accepted: 10/27/2020] [Indexed: 12/30/2022]
Abstract
Vitamin K antagonists are widely used anticoagulants that target vitamin K epoxide reductases (VKOR), a family of integral membrane enzymes. To elucidate their catalytic cycle and inhibitory mechanism, we report 11 x-ray crystal structures of human VKOR and pufferfish VKOR-like, with substrates and antagonists in different redox states. Substrates entering the active site in a partially oxidized state form cysteine adducts that induce an open-to-closed conformational change, triggering reduction. Binding and catalysis are facilitated by hydrogen-bonding interactions in a hydrophobic pocket. The antagonists bind specifically to the same hydrogen-bonding residues and induce a similar closed conformation. Thus, vitamin K antagonists act through mimicking the key interactions and conformational changes required for the VKOR catalytic cycle.
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Affiliation(s)
- Shixuan Liu
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Shuang Li
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Guomin Shen
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | | | - Andrzej M Krezel
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Weikai Li
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA.
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12
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Li S, Liu S, Yang Y, Li W. Characterization of Warfarin Inhibition Kinetics Requires Stabilization of Intramembrane Vitamin K Epoxide Reductases. J Mol Biol 2020; 432:5197-5208. [PMID: 32445640 DOI: 10.1016/j.jmb.2020.05.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 04/24/2020] [Accepted: 05/14/2020] [Indexed: 01/04/2023]
Abstract
Intramembrane enzymes are often difficult for biochemical characterization. Human vitamin K epoxide reductase (VKOR) is the target of warfarin. However, this intramembrane enzyme becomes insensitive to warfarin inhibition in vitro, preventing the characterization of inhibition kinetics for decades. Here we employ structural biology methods to identify stable VKOR and VKOR-like proteins and purify them to near homogeneity. We find that the key to maintain their warfarin sensitivity is to stabilize their native protein conformation in vitro. Reduced glutathione drastically increases the warfarin sensitivity of a VKOR-like protein from Takifugu rubripes, presumably through maintaining a disulfide-bonded conformation. Effective inhibition of human VKOR-like requires also the use of LMNG, a mild detergent developed for crystallography to increase membrane protein stability. Human VKOR needs to be preserved in ER-enriched microsomes to exhibit warfarin sensitivity, whereas human VKOR purified in LMNG is stable only with pre-bound warfarin. Under these optimal conditions, warfarin inhibits with tight-binding kinetics. Overall, our studies show that structural biology methods are ideal for stabilizing intramembrane enzymes. Optimizing toward their inhibitor-binding conformation enables the characterization of enzyme kinetics in difficult cases.
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Affiliation(s)
- Shuang Li
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Shixuan Liu
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Yihu Yang
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Weikai Li
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA.
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13
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Beato S, Marques C, Laizé V, Gavaia PJ, Fernández I. New Insights on Vitamin K Metabolism in Senegalese sole ( Solea senegalensis) Based on Ontogenetic and Tissue-Specific Vitamin K Epoxide Reductase Molecular Data. Int J Mol Sci 2020; 21:E3489. [PMID: 32429051 PMCID: PMC7278968 DOI: 10.3390/ijms21103489] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 05/07/2020] [Accepted: 05/13/2020] [Indexed: 12/17/2022] Open
Abstract
Vitamin K (VK) is a key nutrient for several biological processes (e.g., blood clotting and bone metabolism). To fulfill VK nutritional requirements, VK action as an activator of pregnane X receptor (Pxr) signaling pathway, and as a co-factor of γ-glutamyl carboxylase enzyme, should be considered. In this regard, VK recycling through vitamin K epoxide reductases (Vkors) is essential and should be better understood. Here, the expression patterns of vitamin K epoxide reductase complex subunit 1 (vkorc1) and vkorc1 like 1 (vkorc1l1) were determined during the larval ontogeny of Senegalese sole (Solea senegalensis), and in early juveniles cultured under different physiological conditions. Full-length transcripts for ssvkorc1 and ssvkorc1l1 were determined and peptide sequences were found to be evolutionarily conserved. During larval development, expression of ssvkorc1 showed a slight increase during absence or low feed intake. Expression of ssvkorc1l1 continuously decreased until 24 h post-fertilization, and remained constant afterwards. Both ssvkors were ubiquitously expressed in adult tissues, and highest expression was found in liver for ssvkorc1, and ovary and brain for ssvkorc1l1. Expression of ssvkorc1 and ssvkorc1l1 was differentially regulated under physiological conditions related to fasting and re-feeding, but also under VK dietary supplementation and induced deficiency. The present work provides new and basic molecular clues evidencing how VK metabolism in marine fish is sensitive to nutritional and environmental conditions.
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Affiliation(s)
- Silvia Beato
- Campus de Vegazana, Universidad de León (ULE), s/n, 24071 León, Spain;
| | - Carlos Marques
- Centro de Ciências do Mar (CCMAR), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal; (C.M.); (V.L.); (P.J.G.)
| | - Vincent Laizé
- Centro de Ciências do Mar (CCMAR), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal; (C.M.); (V.L.); (P.J.G.)
| | - Paulo J. Gavaia
- Centro de Ciências do Mar (CCMAR), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal; (C.M.); (V.L.); (P.J.G.)
- Departamento de Ciências Biomédicas e Medicina (DCBM), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
| | - Ignacio Fernández
- Center for Aquaculture Research, Agrarian Technological Institute of Castile and Leon, Ctra. Arévalo, S/n. Zamarramala, 40196 Segovia, Spain
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14
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Granadeiro L, Dirks RP, Ortiz-Delgado JB, Gavaia PJ, Sarasquete C, Laizé V, Cancela ML, Fernández I. Warfarin-exposed zebrafish embryos resembles human warfarin embryopathy in a dose and developmental-time dependent manner - From molecular mechanisms to environmental concerns. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 181:559-571. [PMID: 31238190 DOI: 10.1016/j.ecoenv.2019.06.042] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 06/13/2019] [Accepted: 06/14/2019] [Indexed: 06/09/2023]
Abstract
Warfarin is the most worldwide used anticoagulant drug and rodenticide. Since it crosses placental barrier it can induce warfarin embryopathy (WE), a fetal mortality in neonates characterized by skeletal deformities in addition to brain hemorrhages. Although the effects of warfarin exposure in aquatic off target species were already described, the particular molecular toxicological mechanisms during early development are still unclear. Here, we used zebrafish (Danio rerio) to describe and compare the developmental effects of warfarin exposure (0, 15.13, 75.68 and 378.43 mM) on two distinct early developmental phases (embryos and eleuthero-embryos). Although exposure to both developmental phases induced fish mortality, only embryos exposed to the highest warfarin level exhibited features mimicking mammalian WE, e.g. high mortality, higher incidence of hemorrhages and altered skeletal development, among other effects. To gain insights into the toxic mechanisms underlying warfarin exposure, the transcriptome of embryos exposed to warfarin was explored through RNA-Seq and compared to that of control embryos. 766 differentially expressed (564 up- and 202 down-regulated) genes were identified. Gene Ontology analysis revealed particular cellular components (cytoplasm, extracellular matrix, lysosome and vacuole), biological processes (mainly amino acid and lipid metabolism and response to stimulus) and pathways (oxidative stress response and apoptosis signaling pathways) being significantly overrepresented in zebrafish embryos upon warfarin exposure. Protein-protein interaction further evidenced an altered redox system, blood coagulation and vasculogenesis, visual phototransduction and collagen formation upon warfarin exposure. The present study not only describes for the first time the WE in zebrafish, it provides new insights for a better risk assessment, and highlights the need for programming the rat eradication actions outside the fish spawning season to avoid an impact on off target fish community. The urge for the development of more species-specific anticoagulants for rodent pest control is also highlighted.
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Affiliation(s)
- Luis Granadeiro
- Centro de Ciências do Mar (CCMAR), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
| | - Ron P Dirks
- ZF-screens B.V. J.H. Oortweg 19, 2333, CH Leiden, the Netherlands
| | - Juan B Ortiz-Delgado
- Instituto de Ciencias Marinas de Andalucía-ICMAN/CSIC, Campus Universitario Río San Pedro, Apdo. Oficial, 11510, Puerto Real, Cádiz, Spain
| | - Paulo J Gavaia
- Centro de Ciências do Mar (CCMAR), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal; Departamento de Ciências Biomédicas e Medicina (DCBM), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
| | - Carmen Sarasquete
- Instituto de Ciencias Marinas de Andalucía-ICMAN/CSIC, Campus Universitario Río San Pedro, Apdo. Oficial, 11510, Puerto Real, Cádiz, Spain
| | - Vincent Laizé
- Centro de Ciências do Mar (CCMAR), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
| | - M Leonor Cancela
- Centro de Ciências do Mar (CCMAR), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal; Departamento de Ciências Biomédicas e Medicina (DCBM), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal; Algarve Biomedical Center (ABC) and Centre for Biomedical Research (CBMR), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
| | - Ignacio Fernández
- Centro de Ciências do Mar (CCMAR), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal; Center for Aquaculture Research, Agrarian Technological Institute of Castile and Leon, Ctra. Arévalo, S/n. 40196 Zamarramala, Segovia, Spain.
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15
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VKORC1 and VKORC1L1 have distinctly different oral anticoagulant dose-response characteristics and binding sites. Blood Adv 2019; 2:691-702. [PMID: 29581108 DOI: 10.1182/bloodadvances.2017006775] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 01/22/2018] [Indexed: 01/11/2023] Open
Abstract
Vitamin K reduction is catalyzed by 2 enzymes in vitro: the vitamin K 2,3-epoxide reductase complex subunit 1 (VKORC1) and its isozyme VKORC1-like1 (VKORC1L1). In vivo, VKORC1 reduces vitamin K to sustain γ-carboxylation of vitamin K-dependent proteins, including coagulation factors. Inhibition of VKORC1 by oral anticoagulants (OACs) is clinically used in therapy and in prevention of thrombosis. However, OACs also inhibit VKORC1L1, which was previously shown to play a role in intracellular redox homeostasis in vitro. Here, we report data for the first time on specific inhibition of both VKOR enzymes for various OACs and rodenticides examined in a cell-based assay. Effects on endogenous VKORC1 and VKORC1L1 were independently investigated in genetically engineered HEK 293T cells that were knocked out for the respective genes by CRISPR/Cas9 technology. In general, dose-responses for 4-hydroxycoumarins and 1,3-indandiones were enzyme-dependent, with lower susceptibility for VKORC1L1 compared with VKORC1. In contrast, rodenticides exhibited nearly identical dose-responses for both enzymes. To explain the distinct inhibition pattern, we performed in silico modeling suggesting different warfarin binding sites for VKORC1 and VKORC1L1. We identified arginine residues at positions 38, 42, and 68 in the endoplasmatic reticulum luminal loop of VKORC1L1 responsible for charge-stabilized warfarin binding, resulting in a binding pocket that is diametrically opposite to that of VKORC1. In conclusion, our findings provide insight into structural and molecular drug binding on VKORC1, and especially on VKORC1L1.
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16
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Superwarfarin (Long-Acting Anticoagulant Rodenticides) Poisoning: from Pathophysiology to Laboratory-Guided Clinical Management. Clin Biochem Rev 2019; 40:175-185. [PMID: 31857739 DOI: 10.33176/aacb-19-00029] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Superwarfarins are long-acting anticoagulant rodenticides developed from warfarin. The mechanism of action is by inhibition of vitamin K epoxide reductase, resulting in the inability of the body to recycle vitamin K. Deficiency of vitamin K thereafter leads to inability for the body to synthesise vitamin K-dependent coagulation factors, factor II, VII, IX, and X, leading to prolonged prothrombin time. Due to the bulky aromatic sidechains, superwarfarins have a much longer half-life when compared to warfarin, and exposure to superwarfarins results in a prolonged period of anticoagulation which can result in clinical bleeding. Diagnosis is straightforward in patients with known history of superwarfarin exposure but has proved difficult for patients who did not report superwarfarin intake. Superwarfarin poisoning should therefore be suspected in all patients with unexplained prolongation of prothrombin time, and can be confirmed by their detection in serum. Treatment for superwarfarin poisoning includes rapid correction of factor deficiencies with either 4-factor prothrombin complex concentrate or fresh frozen plasma in patients with active bleeding, and high dose vitamin K therapy given multiple times per day for a prolonged period of weeks to months.
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17
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Au NT, Ryman T, Rettie AE, Hopkins SE, Boyer BB, Black J, Philip J, Yracheta J, Fohner AE, Reyes M, Thornton TA, Austin MA, Thummel KE. Dietary Vitamin K and Association with Hepatic Vitamin K Status in a Yup'ik Study Population from Southwestern Alaska. Mol Nutr Food Res 2018; 62:10.1002/mnfr.201700746. [PMID: 29094808 PMCID: PMC5803412 DOI: 10.1002/mnfr.201700746] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 10/10/2017] [Indexed: 01/15/2023]
Abstract
SCOPE The relationship between dietary vitamin K and plasma PIVKA-II concentration, a biomarker of hepatic vitamin K status, in a Yup'ik study population in southwestern Alaska is investigated. METHODS AND RESULTS A total of 659 male and female, self-reported Yup'ik people, ≥14 years of age, were enrolled. Blood is collected for genotyping and plasma PIVKA-II biomarker analysis. A Yup'ik-specific dietary food frequency questionnaire is used to assess vitamin K intake. Among the participants, 22% report not consuming foods rich in vitamin K during the past year and 36% have a PIVKA-II concentration ≥ 2 ng mL-1 , indicating vitamin K insufficiency. The odds of an elevated PIVKA-II concentration are 33% lower in individuals reporting any versus no consumption of vitamin-K-rich foods. The association is significant after adjusting for CYP4F2*3 genotype. Tundra greens are high in vitamin K1 content, but an exploratory analysis suggests that subsistence meat sources have a greater effect on vitamin K status. CONCLUSIONS A substantial proportion of the Yup'ik population exhibits vitamin K insufficiency, which is associated with low consumption of vitamin K rich foods and which might affect an individual's response to anticoagulant drugs such as warfarin that target the vitamin K cycle.
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Affiliation(s)
- Nicholas T Au
- Department of Medicinal Chemistry, University of Washington, Seattle, WA, USA
| | - Tove Ryman
- Department of Epidemiology, University of Washington, Seattle, WA, USA
| | - Allan E Rettie
- Department of Medicinal Chemistry, University of Washington, Seattle, WA, USA
| | - Scarlett E Hopkins
- Center for Alaska Native Health Research, University of Alaska Fairbanks, Fairbanks, AK, USA
| | - Bert B Boyer
- Center for Alaska Native Health Research, University of Alaska Fairbanks, Fairbanks, AK, USA
| | - Jynene Black
- Center for Alaska Native Health Research, University of Alaska Fairbanks, Fairbanks, AK, USA
| | - Jacques Philip
- Center for Alaska Native Health Research, University of Alaska Fairbanks, Fairbanks, AK, USA
| | - Joseph Yracheta
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA
| | - Alison E Fohner
- Institute for Public Health Genetics, University of Washington, Seattle, WA, USA
| | - Morayma Reyes
- Department of Laboratory Medicine, University of Washington, Seattle, WA, USA
| | | | - Melissa A Austin
- Department of Epidemiology, University of Washington, Seattle, WA, USA
| | - Kenneth E Thummel
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA
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18
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Benoni R, Beck CM, Garza-Sánchez F, Bettati S, Mozzarelli A, Hayes CS, Campanini B. Activation of an anti-bacterial toxin by the biosynthetic enzyme CysK: mechanism of binding, interaction specificity and competition with cysteine synthase. Sci Rep 2017; 7:8817. [PMID: 28821763 PMCID: PMC5562914 DOI: 10.1038/s41598-017-09022-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 07/20/2017] [Indexed: 12/20/2022] Open
Abstract
Contact-dependent growth inhibition (CDI) is a wide-spread mechanism of inter-bacterial competition. CDI+ bacteria deliver CdiA-CT toxins into neighboring bacteria and produce specific immunity proteins that protect against self-intoxication. The CdiA-CT toxin from uropathogenic Escherichia coli 536 is a latent tRNase that is only active when bound to the cysteine biosynthetic enzyme CysK. Remarkably, the CysK:CdiA-CT binding interaction mimics the ‘cysteine synthase’ complex of CysK:CysE. The C-terminal tails of CysE and CdiA-CT each insert into the CysK active-site cleft to anchor the respective complexes. The dissociation constant for CysK:CdiA-CT (Kd ~ 11 nM) is comparable to that of the E. coli cysteine synthase complex (Kd ~ 6 nM), and both complexes bind through a two-step mechanism with a slow isomerization phase after the initial encounter. However, the second-order rate constant for CysK:CdiA-CT binding is two orders of magnitude slower than that of the cysteine synthase complex, suggesting that CysE should outcompete the toxin for CysK occupancy. However, we find that CdiA-CT can effectively displace CysE from pre-formed cysteine synthase complexes, enabling toxin activation even in the presence of excess competing CysE. This adventitious binding, coupled with the very slow rate of CysK:CdiA-CT dissociation, ensures robust nuclease activity in target bacteria.
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Affiliation(s)
- Roberto Benoni
- Dipartimento di Medicina e Chirurgia, Università di Parma, Parma, Italy.,Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Praha, Czech Republic
| | - Christina M Beck
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA, USA.,Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Fernando Garza-Sánchez
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA, USA
| | - Stefano Bettati
- Dipartimento di Medicina e Chirurgia, Università di Parma, Parma, Italy.,Istituto Nazionale Biostrutture e Biosistemi, Rome, Italy
| | - Andrea Mozzarelli
- Istituto Nazionale Biostrutture e Biosistemi, Rome, Italy.,Dipartimento di Scienze degli Alimenti e del Farmaco, Università di Parma, Parma, Italy
| | - Christopher S Hayes
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA, USA. .,Biomolecular Science and Engineering Program, University of California, Santa Barbara, Santa Barbara, CA, USA.
| | - Barbara Campanini
- Dipartimento di Scienze degli Alimenti e del Farmaco, Università di Parma, Parma, Italy.
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19
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Benoni R, De Bei O, Paredi G, Hayes CS, Franko N, Mozzarelli A, Bettati S, Campanini B. Modulation of Escherichia coli serine acetyltransferase catalytic activity in the cysteine synthase complex. FEBS Lett 2017; 591:1212-1224. [PMID: 28337759 DOI: 10.1002/1873-3468.12630] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 02/20/2017] [Accepted: 03/16/2017] [Indexed: 11/09/2022]
Abstract
In bacteria and plants, serine acetyltransferase (CysE) and O-acetylserine sulfhydrylase-A sulfhydrylase (CysK) collaborate to synthesize l-Cys from l-Ser. CysE and CysK bind one another with high affinity to form the cysteine synthase complex (CSC). We demonstrate that bacterial CysE is activated when bound to CysK. CysE activation results from the release of substrate inhibition, with the Ki for l-Ser increasing from 4 mm for free CysE to 16 mm for the CSC. Feedback inhibition of CysE by l-Cys is also relieved in the bacterial CSC. These findings suggest that the CysE active site is allosterically altered by CysK to alleviate substrate and feedback inhibition in the context of the CSC.
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Affiliation(s)
- Roberto Benoni
- Dipartimento di Medicina e Chirurgia, Università di Parma, Italy
| | - Omar De Bei
- Dipartimento di Scienze degli Alimenti e del Farmaco, Università di Parma, Italy
| | - Gianluca Paredi
- Centro Interdipartimentale SITEIA.PARMA, Università di Parma, Italy
| | - Christopher S Hayes
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA, USA.,Biomolecular Science and Engineering Program, University of California, Santa Barbara, CA, USA
| | - Nina Franko
- Dipartimento di Scienze degli Alimenti e del Farmaco, Università di Parma, Italy
| | - Andrea Mozzarelli
- Dipartimento di Scienze degli Alimenti e del Farmaco, Università di Parma, Italy.,INBB (Istituto Nazionale Biostrutture e Biosistemi), Roma, Italy.,Istituto di Biofisica, CNR, Pisa, Italy
| | - Stefano Bettati
- Dipartimento di Medicina e Chirurgia, Università di Parma, Italy.,INBB (Istituto Nazionale Biostrutture e Biosistemi), Roma, Italy
| | - Barbara Campanini
- Dipartimento di Scienze degli Alimenti e del Farmaco, Università di Parma, Italy
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20
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Au NT, Reyes M, Boyer BB, Hopkins SE, Black J, O’Brien D, Fohner AE, Yracheta J, Thornton T, Austin MA, Burke W, Thummel KE, Rettie AE. Dietary and genetic influences on hemostasis in a Yup'ik Alaska Native population. PLoS One 2017; 12:e0173616. [PMID: 28376131 PMCID: PMC5380313 DOI: 10.1371/journal.pone.0173616] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 02/23/2017] [Indexed: 11/23/2022] Open
Abstract
Fish and marine animals are important components of the subsistence diet of Alaska Native people, resulting in a high ω3 PUFA intake. The historical record for circumpolar populations highlights a tendency for facile bleeding, possibly related to ω3 PUFA effects on platelet activation and/or vitamin K-dependent clotting factors. To evaluate these two scenarios in Yup'ik people of southwestern Alaska, we examined the association between dietary ω3 PUFA intake and activities of clotting factor II, V, fibrinogen, PT, INR, PTT, and sP-selectin in 733 study participants, using the nitrogen isotope ratio of red blood cells as a biomarker of ω3 PUFA consumption. sP-selectin alone correlated strongly and inversely with ω3 PUFA consumption. Approximately 36% of study participants exhibited PIVKA-II values above the threshold of 2 ng/ml, indicative of low vitamin K status. To assess genetic influences on vitamin K status, study participants were genotyped for common vitamin K cycle polymorphisms in VKORC1, GGCX and CYP4F2. Only CYP4F2*3 associated significantly with vitamin K status, for both acute (plasma vitamin K) and long-term (PIVKA-II) measures. These findings suggest: (i) a primary association of ω3 PUFAs on platelet activation, as opposed to vitamin K-dependent clotting factor activity, (ii) that reduced CYP4F2 enzyme activity associates with vitamin K status. We conclude that high ω3 PUFA intake promotes an anti-platelet effect and speculate that the high frequency of the CYP4F2*3 allele in Yup'ik people (~45%) evolved in response to a need to conserve body stores of vitamin K due to environmental limitations on its availability.
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Affiliation(s)
- Nicholas T. Au
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington, United States of America
| | - Morayma Reyes
- Department of Laboratory Medicine, University of Washington, Seattle, Washington, United States of America
| | - Bert B. Boyer
- Center for Alaska Native Health Research, University of Alaska Fairbanks, Fairbanks, Alaska, United States of America
| | - Scarlett E. Hopkins
- Center for Alaska Native Health Research, University of Alaska Fairbanks, Fairbanks, Alaska, United States of America
| | - Jynene Black
- Center for Alaska Native Health Research, University of Alaska Fairbanks, Fairbanks, Alaska, United States of America
| | - Diane O’Brien
- Center for Alaska Native Health Research, University of Alaska Fairbanks, Fairbanks, Alaska, United States of America
| | - Alison E. Fohner
- Public Health Genetics, University of Washington, Seattle, Washington, United States of America
| | - Joe Yracheta
- Department of Pharmaceutics, University of Washington, Seattle, Washington, United States of America
| | - Timothy Thornton
- Department of Biostatistics, University of Washington, Seattle, Washington, United States of America
| | - Melissa A. Austin
- Department of Epidemiology, University of Washington, Seattle, Washington, United States of America
| | - Wylie Burke
- Department of Medical Ethics, University of Washington, Seattle, Washington, United States of America
| | - Kenneth E. Thummel
- Department of Pharmaceutics, University of Washington, Seattle, Washington, United States of America
| | - Allan E. Rettie
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington, United States of America
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21
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Shen G, Cui W, Zhang H, Zhou F, Huang W, Liu Q, Yang Y, Li S, Bowman GR, Sadler JE, Gross ML, Li W. Warfarin traps human vitamin K epoxide reductase in an intermediate state during electron transfer. Nat Struct Mol Biol 2016; 24:69-76. [PMID: 27918545 DOI: 10.1038/nsmb.3333] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 10/24/2016] [Indexed: 01/25/2023]
Abstract
Although warfarin is the most widely used anticoagulant worldwide, the mechanism by which warfarin inhibits its target, human vitamin K epoxide reductase (hVKOR), remains unclear. Here we show that warfarin blocks a dynamic electron-transfer process in hVKOR. A major fraction of cellular hVKOR is in an intermediate redox state containing a Cys51-Cys132 disulfide, a characteristic accommodated by a four-transmembrane-helix structure of hVKOR. Warfarin selectively inhibits this major cellular form of hVKOR, whereas disruption of the Cys51-Cys132 disulfide impairs warfarin binding and causes warfarin resistance. Relying on binding interactions identified by cysteine alkylation footprinting and mass spectrometry coupled with mutagenesis analysis, we conducted structure simulations, which revealed a closed warfarin-binding pocket stabilized by the Cys51-Cys132 linkage. Understanding the selective warfarin inhibition of a specific redox state of hVKOR should enable the rational design of drugs that exploit the redox chemistry and associated conformational changes in hVKOR.
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Affiliation(s)
- Guomin Shen
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Weidong Cui
- Department of Chemistry, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Hao Zhang
- Department of Chemistry, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Fengbo Zhou
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Wei Huang
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA.,School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Qian Liu
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA.,Department of Forensic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yihu Yang
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Shuang Li
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Gregory R Bowman
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - J Evan Sadler
- Division of Hematology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Michael L Gross
- Department of Chemistry, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Weikai Li
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
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22
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Jaenecke F, Friedrich-Epler B, Parthier C, Stubbs MT. Membrane composition influences the activity of in vitro refolded human vitamin K epoxide reductase. Biochemistry 2015; 54:6454-61. [PMID: 26435421 DOI: 10.1021/acs.biochem.5b00716] [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 vitamin K epoxide reductase (hVKOR) is an integral membrane protein responsible for the maintenance of reduced vitamin K pools, a prerequisite for the action of γ-glutamyl carboxylase and hence for hemostasis. Here we describe the recombinant expression of hVKOR as an insoluble fusion protein in Escherichia coli, followed by purification and chemical cleavage under denaturing conditions. In vitro renaturation and reconstitution of purified solubilized hVKOR in phospholipids could be established to yield active protein. Crucially, the renatured enzyme is inhibited by the powerful coumarin anticoagulant warfarin, and we demonstrate that enzyme activity depends on lipid composition. The completely synthetic system for protein production allows a rational investigation of the multiple variables in membrane protein folding and paves the way for the provision of pure, active membrane protein for structural studies.
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Affiliation(s)
- Frank Jaenecke
- Institut für Biochemie und Biotechnologie, Martin-Luther Universität Halle-Wittenberg , Kurt-Mothes Strasse 3, D-06120 Halle/Saale, Germany.,ZIK HALOmem , Kurt-Mothes Strasse 3, D-06120 Halle/Saale, Germany
| | - Beatrice Friedrich-Epler
- Institut für Biochemie und Biotechnologie, Martin-Luther Universität Halle-Wittenberg , Kurt-Mothes Strasse 3, D-06120 Halle/Saale, Germany
| | - Christoph Parthier
- Institut für Biochemie und Biotechnologie, Martin-Luther Universität Halle-Wittenberg , Kurt-Mothes Strasse 3, D-06120 Halle/Saale, Germany
| | - Milton T Stubbs
- Institut für Biochemie und Biotechnologie, Martin-Luther Universität Halle-Wittenberg , Kurt-Mothes Strasse 3, D-06120 Halle/Saale, Germany.,ZIK HALOmem , Kurt-Mothes Strasse 3, D-06120 Halle/Saale, Germany
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23
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Lu Y, Hou X, Zhao X, Liu M, Shen F, Ren Y, Liu Y, Huo S, Shen S. Kinetics and mechanism of oxidation of 3,6-dioxa-1,8-octanedithiol and dl-dithiothreitol by a platinum(IV) complex. TRANSIT METAL CHEM 2015. [DOI: 10.1007/s11243-015-9995-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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24
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Oldenburg J, Watzka M, Bevans CG. VKORC1 and VKORC1L1: Why do Vertebrates Have Two Vitamin K 2,3-Epoxide Reductases? Nutrients 2015; 7:6250-80. [PMID: 26264021 PMCID: PMC4555119 DOI: 10.3390/nu7085280] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 07/08/2015] [Accepted: 07/15/2015] [Indexed: 01/01/2023] Open
Abstract
Among all cellular life on earth, with the exception of yeasts, fungi, and some prokaryotes, VKOR family homologs are ubiquitously encoded in nuclear genomes, suggesting ancient and important biological roles for these enzymes. Despite single gene and whole genome duplications on the largest evolutionary timescales, and the fact that most gene duplications eventually result in loss of one copy, it is surprising that all jawed vertebrates (gnathostomes) have retained two paralogous VKOR genes. Both VKOR paralogs function as entry points for nutritionally acquired and recycled K vitamers in the vitamin K cycle. Here we present phylogenetic evidence that the human paralogs likely arose earlier than gnathostomes, possibly in the ancestor of crown chordates. We ask why gnathostomes have maintained these paralogs throughout evolution and present a current summary of what we know. In particular, we look to published studies about tissue- and developmental stage-specific expression, enzymatic function, phylogeny, biological roles and associated pathways that together suggest subfunctionalization as a major influence in evolutionary fixation of both paralogs. Additionally, we investigate on what evolutionary timescale the paralogs arose and under what circumstances in order to gain insight into the biological raison d’être for both VKOR paralogs in gnathostomes.
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Affiliation(s)
- Johannes Oldenburg
- Institute of Experimental Haematology and Transfusion Medicine, University Clinic Bonn, Bonn 53105, Germany.
| | - Matthias Watzka
- Institute of Experimental Haematology and Transfusion Medicine, University Clinic Bonn, Bonn 53105, Germany.
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25
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Fernández I, Santos A, Cancela ML, Laizé V, Gavaia PJ. Warfarin, a potential pollutant in aquatic environment acting through Pxr signaling pathway and γ-glutamyl carboxylation of vitamin K-dependent proteins. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2014; 194:86-95. [PMID: 25094061 DOI: 10.1016/j.envpol.2014.07.015] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Revised: 07/04/2014] [Accepted: 07/10/2014] [Indexed: 06/03/2023]
Abstract
Warfarin-induced vitamin K (VK) recycling impairment is used worldwide as a rodenticide and human thromboembolic prophylactic. Since VK metabolism/signaling pathways have been conserved throughout vertebrate evolution, its release to the environment might impact on aquatic organisms. Present study assessed the toxic effect of warfarin (0, 5, 25 and 125 mg L(-1)) on zebrafish development and characterized underlying mechanisms of action through qPCR analysis of VK-related genes. Expression of pregnane X receptor (pxr), the nuclear receptor binding vitamin K, was ubiquitous in zebrafish and suggests that warfarin exposure may interfere with several biological processes. Indeed, warfarin exposure of zebrafish larvae caused hemorrhages in brain, skeletal deformities and triggered ectopic calcifications, which may be the consequence of an altered γ-carboxylation of VK-dependent proteins and/or pxr signaling. This study provides new insights into warfarin effects as a bone homeostasis disruptor and soft tissue calcification inductor, and its potential risk for aquatic environments.
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Affiliation(s)
- Ignacio Fernández
- Centre of Marine Sciences (CCMAR), University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal.
| | - Adriana Santos
- Centre of Marine Sciences (CCMAR), University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
| | - M Leonor Cancela
- Centre of Marine Sciences (CCMAR), University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal; Department of Biomedical Sciences and Medicine (DCBM), University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
| | - Vincent Laizé
- Centre of Marine Sciences (CCMAR), University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
| | - Paulo J Gavaia
- Centre of Marine Sciences (CCMAR), University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
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26
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Corrigendum to “Determination of the warfarin inhibition constant Ki for vitamin K 2,3-epoxide reductase complex subunit-1 (VKORC1) using an in vitro DTT-driven assay” [BBAGEN (2013) 4202–4210]. Biochim Biophys Acta Gen Subj 2014. [DOI: 10.1016/j.bbagen.2014.03.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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27
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Oldenburg J, Müller CR, Rost S, Watzka M, Bevans CG. Comparative genetics of warfarin resistance. Hamostaseologie 2013; 34:143-59. [PMID: 24287886 DOI: 10.5482/hamo-13-09-0047] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 09/25/2013] [Indexed: 11/05/2022] Open
Abstract
Warfarin and other 4-hydroxycoumarin-based oral anticoagulants targeting vitamin K 2,3-epoxide reductase complex subunit 1 (VKORC1) are administered to humans, mice and rats with different purposes in mind - to act as pesticides in high-dosage baits for killing rodents, but also to save lives when administered in low dosages as antithrombotic drugs in humans. However, high-dosage warfarin used to control rodent populations has resulted in numerous mutations causing warfarin resistance. Currently, six single missense mutations in mice, 12 distinct missense mutations in rats, as well as compound heterozygous or homozygous mutations with up to six distinct missense mutations per Vkorc1 allele have been described. Warfarin resistance missense mutations for human VKORC1 have also been found world-wide, but differ characteristically from those in rodents. In humans, 26 distinct mutations have been characterized, but occur only rarely either in heterozygous or, even rarer, in homozygous form. In this review, we summarize the known VKORC1 missense mutations causing warfarin and other 4-hydroxycoumarin drug resistance, identify genomics databases as new sources of data, explore possible underlying genetic mechanisms, and summarize similarities and differences between warfarin resistant VKORC1 variants in humans and rodents.
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Affiliation(s)
- J Oldenburg
- Prof. Dr. Johannes Oldenburg, Institute of Experimental Haematology and Transfusion Medicine, University Clinic Bonn, Sigmund Freud Str. 25, 53105 Bonn, Germany, E-mail: , Tel. +49/(0)228/287 51 75, Fax +49/(0)228/287 51 76
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28
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Human VKORC1 mutations cause variable degrees of 4-hydroxycoumarin resistance and affect putative warfarin binding interfaces. Blood 2013; 122:2743-50. [PMID: 23982176 DOI: 10.1182/blood-2013-05-501692] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Since the discovery of warfarin-sensitive vitamin K 2,3-epoxide reductase complex subunit 1 (VKORC1), 26 human VKORC1 (hVKORC1) missense mutations have been associated with oral anticoagulant resistance (OACR). Assessment of warfarin resistance using the "classical" dithiothreitol-driven vitamin K 2,3-epoxide reductase (VKOR) assay has not reflected clinical resistance phenotypes for most mutations. Here, we present half maximal inhibitory concentrations (IC50) results for 21 further hVKORC1 mutations obtained using a recently validated cell-based assay (J Thromb Haemost 11(5):872). In contrast to results from the dithiothreitol-driven VKOR assay, all mutations exhibited basal VKOR activity and warfarin IC50 values that correspond well to patient OACR phenotypes. Thus, the present assay is useful for functional investigations of VKORC1 and oral anticoagulant inhibition of the vitamin K cycle. Additionally, we modeled hVKORC1 on the previously solved structure of a homologous bacterial enzyme and performed in silico docking of warfarin on this model. We identified one binding site delineated by 3 putative binding interfaces. These interfaces comprise linear sequences of the endoplasmic reticulum-lumenal loop (Ser52-Phe55) and the first (Leu22-Lys30) and fourth (Phe131-Thr137) transmembrane helices. All known OACR-associated hVKORC1 mutations are located in or around these putative interfaces, supporting our model.
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