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Ma MY, Deng G, Zhu WZ, Sun M, Jiang LY, Li WH, Liu YB, Guo L, Song BL, Zhao X. Defects in CYB5A and CYB5B impact sterol-C4 oxidation in cholesterol biosynthesis and demonstrate regulatory roles of dimethyl sterols. Cell Rep 2024; 43:114912. [PMID: 39489939 DOI: 10.1016/j.celrep.2024.114912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 06/07/2024] [Revised: 09/13/2024] [Accepted: 10/09/2024] [Indexed: 11/05/2024] Open
Abstract
Cytochrome b5 (CYB5) is a hemoprotein crucial for electron transfer to oxygenases. Although microsomal CYB5A is required for sterol C4-demethylation in vitro, cholesterol biosynthesis remains intact in Cyb5a knockout mice. Here, we show that knockout of mitochondrial CYB5B, rather than CYB5A, blocks cholesterol biosynthesis at the sterol-C4 oxidation step in HeLa cells, causing an accumulation of testis meiosis-activating sterol (T-MAS) and dihydro-T-MAS. Surprisingly, liver-specific Cyb5b knockout (L-Cyb5b-/-) mice exhibit normal cholesterol metabolism. Further knockdown of Cyb5a in L-Cyb5b-/- (L-Cyb5b-/-/short hairpin [sh]Cyb5a) mice leads to a marked accumulation of T-MAS and dihydro-T-MAS, indicating that either CYB5A or CYB5B is required for sterol C4-demethylation. The L-Cyb5b-/-/shCyb5a mice are largely normal, with lower sterol regulatory element-binding protein (SREBP)-target gene expression during refeeding and higher liver triglyceride levels while fasting, as T-MAS and dihydro-T-MAS inhibit the SREBP pathway and activate the PPARγ pathway. In summary, CYB5A and CYB5B compensate for sterol C4-demethylation, and T-MAS and dihydro-T-MAS can modulate the SREBP and PPARγ pathways.
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Affiliation(s)
- Mei-Yan Ma
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Taikang Center for Life and Medical Sciences, Wuhan University, Wuhan 430000, China
| | - Gang Deng
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Taikang Center for Life and Medical Sciences, Wuhan University, Wuhan 430000, China
| | - Wen-Zhuo Zhu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Taikang Center for Life and Medical Sciences, Wuhan University, Wuhan 430000, China
| | - Ming Sun
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Taikang Center for Life and Medical Sciences, Wuhan University, Wuhan 430000, China
| | - Lu-Yi Jiang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Taikang Center for Life and Medical Sciences, Wuhan University, Wuhan 430000, China
| | - Wei-Hui Li
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Taikang Center for Life and Medical Sciences, Wuhan University, Wuhan 430000, China
| | - Yuan-Bin Liu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Taikang Center for Life and Medical Sciences, Wuhan University, Wuhan 430000, China
| | - Lin Guo
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Taikang Center for Life and Medical Sciences, Wuhan University, Wuhan 430000, China
| | - Bao-Liang Song
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Taikang Center for Life and Medical Sciences, Wuhan University, Wuhan 430000, China.
| | - Xiaolu Zhao
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Taikang Center for Life and Medical Sciences, Wuhan University, Wuhan 430000, China.
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Barata IS, Rueff J, Kranendonk M, Esteves F. Pleiotropy of Progesterone Receptor Membrane Component 1 in Modulation of Cytochrome P450 Activity. J Xenobiot 2024; 14:575-603. [PMID: 38804287 PMCID: PMC11130977 DOI: 10.3390/jox14020034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 03/15/2024] [Revised: 04/26/2024] [Accepted: 04/29/2024] [Indexed: 05/29/2024] Open
Abstract
Progesterone receptor membrane component 1 (PGRMC1) is one of few proteins that have been recently described as direct modulators of the activity of human cytochrome P450 enzymes (CYP)s. These enzymes form a superfamily of membrane-bound hemoproteins that metabolize a wide variety of physiological, dietary, environmental, and pharmacological compounds. Modulation of CYP activity impacts the detoxification of xenobiotics as well as endogenous pathways such as steroid and fatty acid metabolism, thus playing a central role in homeostasis. This review is focused on nine main topics that include the most relevant aspects of past and current PGRMC1 research, focusing on its role in CYP-mediated drug metabolism. Firstly, a general overview of the main aspects of xenobiotic metabolism is presented (I), followed by an overview of the role of the CYP enzymatic complex (IIa), a section on human disorders associated with defects in CYP enzyme complex activity (IIb), and a brief account of cytochrome b5 (cyt b5)'s effect on CYP activity (IIc). Subsequently, we present a background overview of the history of the molecular characterization of PGRMC1 (III), regarding its structure, expression, and intracellular location (IIIa), and its heme-binding capability and dimerization (IIIb). The next section reflects the different effects PGRMC1 may have on CYP activity (IV), presenting a description of studies on the direct effects on CYP activity (IVa), and a summary of pathways in which PGRMC1's involvement may indirectly affect CYP activity (IVb). The last section of the review is focused on the current challenges of research on the effect of PGRMC1 on CYP activity (V), presenting some future perspectives of research in the field (VI).
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Affiliation(s)
- Isabel S. Barata
- Department of Pediatrics, Division of Endocrinology, Diabetology and Metabolism, University Children’s Hospital, University of Bern, 3010 Bern, Switzerland;
- Translational Hormone Research Program, Department of Biomedical Research, University of Bern, 3010 Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, 3012 Bern, Switzerland
| | - José Rueff
- ToxOmics, NOVA Medical School, Faculdade de Ciências Médicas, NMS|FCM, Universidade NOVA de Lisboa, Campo Mártires da Pátria 130, 1169-056 Lisboa, Portugal;
| | - Michel Kranendonk
- ToxOmics, NOVA Medical School, Faculdade de Ciências Médicas, NMS|FCM, Universidade NOVA de Lisboa, Campo Mártires da Pátria 130, 1169-056 Lisboa, Portugal;
| | - Francisco Esteves
- ToxOmics, NOVA Medical School, Faculdade de Ciências Médicas, NMS|FCM, Universidade NOVA de Lisboa, Campo Mártires da Pátria 130, 1169-056 Lisboa, Portugal;
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Nolden M, Paine MJI, Nauen R. Biochemical profiling of functionally expressed CYP6P9 variants of the malaria vector Anopheles funestus with special reference to cytochrome b 5 and its role in pyrethroid and coumarin substrate metabolism. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2022; 182:105051. [PMID: 35249659 DOI: 10.1016/j.pestbp.2022.105051] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Academic Contribution Register] [Received: 12/22/2021] [Revised: 01/24/2022] [Accepted: 01/24/2022] [Indexed: 06/14/2023]
Abstract
Cytochrome P450 monooxygenases (P450s) are well studied enzymes catalyzing the oxidative metabolism of xenobiotics in insects including mosquitoes. Their duplication and upregulation in agricultural and public health pests such as anopheline mosquitoes often leads to an enhanced metabolism of insecticides which confers resistance. In the laboratory strain Anopheles funestus FUMOZ-R the duplicated P450s CYP6P9a and CYP6P9b are highly upregulated and proven to confer pyrethroid resistance. Microsomal P450 activity is regulated by NADPH cytochrome P450 oxidoreductase (CPR) required for electron transfer, whereas the modulatory role of cytochrome b5 (CYB5) on insect P450 activity is less clear. In previous studies CYP6P9a and CYP6P9b were recombinantly expressed in tandem with An. gambiae CPR using E. coli-expression systems and CYB5 added to the reaction mix to enhance activity. However, the precise role of CYB5 on substrate turn-over when combined with CYP6P9a and CYP6P9b remains poorly investigated, thus one objective of our study was to address this knowledge gap. In contrast to the CYP6P9 variants, the expression levels of both CYB5 and CPR were not upregulated in the pyrethroid resistant FUMOZ-R strain when compared to the susceptible FANG strain, suggesting no immediate regulatory role of these genes in pyrethroid resistance in FUMOZ-R. Here, for the first time we recombinantly expressed CYP6P9a and CYP6P9b from An. funestus in a baculovirus expression system using High-5 insect cells. Co-expression of each enzyme with CPR from either An. gambiae or An. funestus did not reveal noteworthy differences in catalytic capacity. Whereas the co-expression of An. funestus CYB5 - tested at different multiplicity of infection (MOI) ratios - resulted in a significantly higher metabolization of coumarin substrates as measured by fluorescence assays. This was confirmed by Michaelis-Menten kinetics using the most active substrate, 7-benzyloxymethoxy-4-trifluoromethylcoumarin (BOMFC). We observed a similar increase in coumarin substrate turnover by adding human CYB5 to the reaction mix. Finally, we compared by UPLC-MS/MS analysis the depletion rate of deltamethrin and the formation of 4'OH-deltamethrin by recombinantly expressed CYP6P9a and CYP6P9b with and without CYB5 and detected no difference in the extent of deltamethrin metabolism. Our results suggest that co-expression (or addition) of CYB5 with CYP6P9 variants, recombinantly expressed in insect cells, can significantly enhance their metabolic capacity to oxidize coumarins, but not deltamethrin.
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Affiliation(s)
- Melanie Nolden
- Bayer AG, Crop Science Division, Alfred Nobel Str. 50, D-40789 Monheim am Rhein, Germany; Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, United Kingdom
| | - Mark J I Paine
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, United Kingdom
| | - Ralf Nauen
- Bayer AG, Crop Science Division, Alfred Nobel Str. 50, D-40789 Monheim am Rhein, Germany.
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Kaur P, Shergill R, Mehta RG, Singh B, Arora S. Biofunctional significance of multi-herbal combination against paracetamol-induced hepatotoxicity in Wistar rats. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:61021-61046. [PMID: 34165748 DOI: 10.1007/s11356-021-15019-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Academic Contribution Register] [Received: 01/13/2021] [Accepted: 06/16/2021] [Indexed: 06/13/2023]
Abstract
A multi-herbal combination (MHC) of five herbs, namely Punica granatum L., Putranjiva roxburghii Wall., Swertia chirata Buch.-Ham., Tinospora cordifolia (Willd.) Miers and Trigonella corniculata L. was assessed against the paracetamol-induced acute hepatotoxicity in female Wistar rats. The animals were randomly assorted into seven groups with six animals in each group. The rats were pre-treated with MHC (50, 100, and 200 mg/kg bw) and silymarin (50 mg/kg bw) once daily for seven consecutive days via oral route followed by administration of paracetamol (3 g/kg bw) on day 7, an hour after the last administration of MHC and silymarin. It was observed that MHC administration significantly (p ≤ 0.05) overturned the paracetamol-induced increase in serum liver function biomarkers (serum glutamic oxaloacetic transaminase, serum glutamic pyruvic transaminase, alkaline phosphatase, and total bilirubin), phase I reaction enzymes (NADPH-cytochrome P450 reductase and NADH-cytochrome b5 reductase), and oxidant biomarkers (lactate dehydrogenase, lipid peroxidation, lipid hydroperoxides, and protein content). MHC administration also reinstated the paracetamol-induced significant decrease (p ≤ 0.05) in haematological indices (haematocrit, haemoglobin, red and white blood cells, and platelets), phase II reaction enzymes (glutathione-S-transferase and DT-diaphorase), membrane-bound enzymes (Na+/K+-ATPase, Ca2+-ATPase, and Mg2+-ATPase), and antioxidant biomarkers (reduced glutathione, superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase). Overall, MHC at 200 mg/kg bw dose significantly (p ≤ 0.05) sheltered the red blood cells from the assault of free radicals, stabilized the structural and functional integrity of hepatocytes, hindered acetaminophen (APAP) biotransformation to its toxic metabolites, and endorsed conjugating abilities to detoxify toxic entities. Furthermore, MHC significantly (p ≤ 0.05) activated enzymatic machinery to scavenge/inhibit the formation of reactive oxygen species, regulated nucleic acid metabolism, surface potential, and membrane fluidity, attenuated tissue breakdown, quenched peroxyl radicals, and provided protection against tissue injury. The necroinflammatory scores revealed strong evidence of MHC (200 mg/kg bw) effectiveness against the paracetamol-induced hepatotoxicity in rats at p ≤ 0.05. The synergistic effect of major inherent phytoconstituents (kaempferol, ellagic acid, and gallic acid), detected by HPLC-PDA, in MHC might have overturned the paracetamol-induced biochemical toxic alterations in rat liver.
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Affiliation(s)
- Pardeep Kaur
- Department of Botanical & Environmental Sciences, Guru Nanak Dev University, Amritsar, Punjab, 143005, India
| | - Robin Shergill
- Department of Botanical & Environmental Sciences, Guru Nanak Dev University, Amritsar, Punjab, 143005, India.
- Khalsa College for Women, Amritsar, Punjab, 143002, India.
| | - Rajendra G Mehta
- Cancer Biology Division, IIT Research Institute and Department of Biological Sciences, Illinois Institute of Technology, Chicago, IL, 60616, USA
| | - Balbir Singh
- Department of Pharmaceutical Sciences, Guru Nanak Dev University, Amritsar, Punjab, 143005, India.
| | - Saroj Arora
- Department of Botanical & Environmental Sciences, Guru Nanak Dev University, Amritsar, Punjab, 143005, India.
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Miura A, Hosono T, Seki T. Macrophage potentiates the recovery of liver zonation and metabolic function after acute liver injury. Sci Rep 2021; 11:9730. [PMID: 33958644 PMCID: PMC8102573 DOI: 10.1038/s41598-021-88989-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 09/04/2020] [Accepted: 04/20/2021] [Indexed: 02/07/2023] Open
Abstract
The liver is an exclusive organ with tremendous regenerative capacity. Liver metabolic functions exhibit spatial heterogeneity, reflecting liver zonation. The mechanisms controlling the proliferation of hepatocytes and the accompanying matrix reconstruction during regeneration have been well explored, but the recovery potential of differentiated metabolic functions and zonation after liver injury remains unclear. We employed a mouse model of carbon tetrachloride (CCl4) induced-acute liver injury with clodronate-induced macrophage depletion to clarify the impact of liver injury on liver metabolism and recovery dynamics of metabolic function and liver zonation during regeneration. Depleting macrophages suppressed tissue remodelling and partially delayed cell proliferation during regeneration after liver injury. In addition, recovery of metabolic functions was delayed by suppressing the tissue remodelling caused by the depleted macrophages. The model revealed that drug metabolic function was resilient against the dysfunction caused by liver injury, but glutamine synthesis was not. Metabolomic analysis revealed that liver branched-chain amino acid (BCAA) and carbohydrate metabolism were suppressed by injury. The plasma BCAA concentration reflected recovery of hepatic function during regeneration. Our study reveals one aspect of the regenerative machinery for hepatic metabolism following acute liver injury.
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Affiliation(s)
- Atsushi Miura
- General Research Institute, Nihon University Collage of Bioresource Sciences, Fujisawa, Kanagawa 252-0880 Japan
| | - Takashi Hosono
- Department of Applied Life Sciences, Nihon University Graduate School of Bioresource Sciences, Fujisawa, Kanagawa 252-0880 Japan ,Department of Chemistry and Life Science, Nihon University Collage of Bioresource Sciences, Fujisawa, Kanagawa 252-0880 Japan
| | - Taiichiro Seki
- General Research Institute, Nihon University Collage of Bioresource Sciences, Fujisawa, Kanagawa 252-0880 Japan ,Department of Applied Life Sciences, Nihon University Graduate School of Bioresource Sciences, Fujisawa, Kanagawa 252-0880 Japan ,Department of Chemistry and Life Science, Nihon University Collage of Bioresource Sciences, Fujisawa, Kanagawa 252-0880 Japan
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6
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Lees RS, Ismail HM, Logan RAE, Malone D, Davies R, Anthousi A, Adolfi A, Lycett GJ, Paine MJI. New insecticide screening platforms indicate that Mitochondrial Complex I inhibitors are susceptible to cross-resistance by mosquito P450s that metabolise pyrethroids. Sci Rep 2020; 10:16232. [PMID: 33004954 PMCID: PMC7530702 DOI: 10.1038/s41598-020-73267-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 06/01/2020] [Accepted: 09/11/2020] [Indexed: 12/01/2022] Open
Abstract
Fenazaquin, pyridaben, tolfenpyrad and fenpyroximate are Complex I inhibitors offering a new mode of action for insecticidal malaria vector control. However, extended exposure to pyrethroid based products such as long-lasting insecticidal nets (LLINs) has created mosquito populations that are largely pyrethroid-resistant, often with elevated levels of P450s that can metabolise and neutralise diverse substrates. To assess cross-resistance liabilities of the Complex I inhibitors, we profiled their susceptibility to metabolism by P450s associated with pyrethroid resistance in Anopheles gambiae (CYPs 6M2, 6P3, 6P4, 6P5, 9J5, 9K1, 6Z2) and An. funestus (CYP6P9a). All compounds were highly susceptible. Transgenic An. gambiae overexpressing CYP6M2 or CYP6P3 showed reduced mortality when exposed to fenpyroximate and tolfenpyrad. Mortality from fenpyroximate was also reduced in pyrethroid-resistant strains of An. gambiae (VK7 2014 and Tiassalé 13) and An. funestus (FUMOZ-R). P450 inhibitor piperonyl butoxide (PBO) significantly enhanced the efficacy of fenpyroximate and tolfenpyrad, fully restoring mortality in fenpyroximate-exposed FUMOZ-R. Overall, results suggest that in vivo and in vitro assays are a useful guide in the development of new vector control products, and that the Complex I inhibitors tested are susceptible to metabolic cross-resistance and may lack efficacy in controlling pyrethroid resistant mosquitoes.
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Affiliation(s)
- Rosemary S Lees
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Hanafy M Ismail
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Rhiannon A E Logan
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - David Malone
- Innovative Vector Control Consortium, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Rachel Davies
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Amalia Anthousi
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Adriana Adolfi
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Gareth J Lycett
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK.
| | - Mark J I Paine
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK.
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7
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Modulation of CYP2C9 activity and hydrogen peroxide production by cytochrome b 5. Sci Rep 2020; 10:15571. [PMID: 32968106 PMCID: PMC7511354 DOI: 10.1038/s41598-020-72284-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 04/03/2020] [Accepted: 08/28/2020] [Indexed: 11/09/2022] Open
Abstract
Cytochromes P450 (CYP) play a major role in drug detoxification, and cytochrome b5 (cyt b5) stimulates the catalytic cycle of mono-oxygenation and detoxification reactions. Collateral reactions of this catalytic cycle can lead to a significant production of toxic reactive oxygen species (ROS). One of the most abundant CYP isoforms in the human liver is CYP2C9, which catalyzes the metabolic degradation of several drugs including nonsteroidal anti-inflammatory drugs. We studied modulation by microsomal membrane-bound and soluble cyt b5 of the hydroxylation of salicylic acid to gentisic acid and ROS release by CYP2C9 activity in human liver microsomes (HLMs) and by CYP2C9 baculosomes. CYP2C9 accounts for nearly 75% of salicylic acid hydroxylation in HLMs at concentrations reached after usual aspirin doses. The anti-cyt b5 antibody SC9513 largely inhibits the rate of salicylic acid hydroxylation by CYP2C9 in HLMs and CYP2C9 baculosomes, increasing the KM approximately threefold. Besides, soluble human recombinant cyt b5 stimulates the Vmax nearly twofold while it decreases nearly threefold the Km value in CYP2C9 baculosomes. Regarding NADPH-dependent ROS production, soluble recombinant cyt b5 is a potent inhibitor both in HLMs and in CYP2C9 baculosomes, with inhibition constants of 1.04 ± 0.25 and 0.53 ± 0.06 µM cyt b5, respectively. This study indicates that variability in cyt b5 might be a major factor underlying interindividual variability in the metabolism of CYP2C9 substrates.
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Yoo SE, Yi M, Kim WY, Cho SA, Lee SS, Lee SJ, Shin JG. Influences of cytochrome b5 expression and its genetic variant on the activity of CYP2C9, CYP2C19 and CYP3A4. Drug Metab Pharmacokinet 2019; 34:201-208. [PMID: 30992242 DOI: 10.1016/j.dmpk.2019.03.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 04/17/2018] [Revised: 03/15/2019] [Accepted: 03/27/2019] [Indexed: 11/28/2022]
Abstract
The objective of the present study was to investigate the effects of cytochrome b5 (cytb5) on the drug metabolism catalyzed by CYP2C9, CYP2C19 and CYP3A4. Activities of CYP2C9, CYP2C19, and CYP3A4 were determined by using the prototypical substrates tolbutamide, omeprazole and midazolam, respectively. Cytb5 protein and mRNA contents showed large inter-individual variations with 11- and 6-fold range, respectively. All of three P450s showed an increased activity in proportion to the amount of cytb5 expression. Particularly, CYP3A4 showed the strongest correlation between cytb5 protein amount and the activity, followed by CYP2C9 and CYP2C19. The putative splicing variant, c.288G>A (rs7238987) was identified and was screened in 36 liver tissues by direct DNA sequencing. Liver tissues having a splicing variant exhibited unexpected sizes of cytb5 mRNA and a decreased expression tendency of cytb5 protein compared to the wild-type. A decreased activity in the metabolism of the CYP2C19 substrate omeprazole was observed in liver tissues carrying the splicing variant when compared to the wild-type Cytb5 (P < 0.05). The present results propose that different expression of cytb5 can cause variations in CYP mediated drug metabolism, which may explain, at least in part, the inter-individual difference in drug responses in addition to the CYP genetic polymorphisms.
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Affiliation(s)
- Sung-Eun Yoo
- Department of Pharmacology and PharmacoGenomics Research Center, Inje University College of Medicine, Busan, Republic of Korea
| | - MyeongJin Yi
- Department of Pharmacology and PharmacoGenomics Research Center, Inje University College of Medicine, Busan, Republic of Korea
| | - Woo-Young Kim
- Department of Pharmacology and PharmacoGenomics Research Center, Inje University College of Medicine, Busan, Republic of Korea
| | - Sun-Ah Cho
- Department of Pharmacology and PharmacoGenomics Research Center, Inje University College of Medicine, Busan, Republic of Korea
| | - Sang Seop Lee
- Department of Pharmacology and PharmacoGenomics Research Center, Inje University College of Medicine, Busan, Republic of Korea
| | - Su-Jun Lee
- Department of Pharmacology and PharmacoGenomics Research Center, Inje University College of Medicine, Busan, Republic of Korea.
| | - Jae-Gook Shin
- Department of Pharmacology and PharmacoGenomics Research Center, Inje University College of Medicine, Busan, Republic of Korea; Department of Clinical Pharmacology, Inje University Busan Paik Hospital, Busan, Republic of Korea.
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Reed L, Indra R, Mrizova I, Moserova M, Schmeiser HH, Wolf CR, Henderson CJ, Stiborova M, Phillips DH, Arlt VM. Application of hepatic cytochrome b 5/P450 reductase null (HBRN) mice to study the role of cytochrome b 5 in the cytochrome P450-mediated bioactivation of the anticancer drug ellipticine. Toxicol Appl Pharmacol 2019; 366:64-74. [PMID: 30685480 PMCID: PMC6382462 DOI: 10.1016/j.taap.2019.01.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 11/04/2018] [Revised: 01/14/2019] [Accepted: 01/22/2019] [Indexed: 01/30/2023]
Abstract
The anticancer drug ellipticine exerts its genotoxic effects after metabolic activation by cytochrome P450 (CYP) enzymes. The present study has examined the role of cytochrome P450 oxidoreductase (POR) and cytochrome b5 (Cyb5), electron donors to P450 enzymes, in the CYP-mediated metabolism and disposition of ellipticine in vivo. We used Hepatic Reductase Null (HRN) and Hepatic Cytochrome b5/P450 Reductase Null (HBRN) mice. HRN mice have POR deleted specifically in hepatocytes; HBRN mice also have Cyb5 deleted in the liver. Mice were treated once with 10 mg/kg body weight ellipticine (n = 4/group) for 24 h. Ellipticine-DNA adduct levels measured by 32P-postlabelling were significantly lower in HRN and HBRN livers than in wild-type (WT) livers; however no significant difference was observed between HRN and HBRN livers. Ellipticine-DNA adduct formation in WT, HRN and HBRN livers correlated with Cyp1a and Cyp3a enzyme activities measured in hepatic microsomes in the presence of NADPH confirming the importance of P450 enzymes in the bioactivation of ellipticine in vivo. Hepatic microsomal fractions were also utilised in incubations with ellipticine and DNA in the presence of NADPH, cofactor for POR, and NADH, cofactor for Cyb5 reductase (Cyb5R), to examine ellipticine-DNA adduct formation. With NADPH adduct formation decreased as electron donors were lost which correlated with the formation of the reactive metabolites 12- and 13-hydroxy-ellipticine in hepatic microsomes. No difference in adduct formation was observed in the presence of NADH. Our study demonstrates that Cyb5 contributes to the P450-mediated bioactivation of ellipticine in vitro, but not in vivo.
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Affiliation(s)
- Lindsay Reed
- Department of Analytical, Environmental and Forensic Sciences, MRC-PHE Centre for Environment and Health, King's College London, London, United Kingdom
| | - Radek Indra
- Department of Biochemistry, Faculty of Science, Charles University, Prague, Czech Republic
| | - Iveta Mrizova
- Department of Biochemistry, Faculty of Science, Charles University, Prague, Czech Republic
| | - Michaela Moserova
- Department of Biochemistry, Faculty of Science, Charles University, Prague, Czech Republic
| | - Heinz H Schmeiser
- Division of Radiopharmaceutical Chemistry, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - C Roland Wolf
- Division of Cancer Research, Jacqui Wood Cancer Centre, School of Medicine, University of Dundee, Ninewells Hospital, Dundee, United Kingdom
| | - Colin J Henderson
- Division of Cancer Research, Jacqui Wood Cancer Centre, School of Medicine, University of Dundee, Ninewells Hospital, Dundee, United Kingdom
| | - Marie Stiborova
- Department of Biochemistry, Faculty of Science, Charles University, Prague, Czech Republic
| | - David H Phillips
- Department of Analytical, Environmental and Forensic Sciences, MRC-PHE Centre for Environment and Health, King's College London, London, United Kingdom
| | - Volker M Arlt
- Department of Analytical, Environmental and Forensic Sciences, MRC-PHE Centre for Environment and Health, King's College London, London, United Kingdom.
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Pal A, Pal A, Banerjee S, Batabyal S, Chatterjee PN. Mutation in Cytochrome B gene causes debility and adverse effects on health of sheep. Mitochondrion 2019; 46:393-404. [PMID: 30660753 DOI: 10.1016/j.mito.2018.10.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 05/20/2018] [Revised: 09/02/2018] [Accepted: 10/24/2018] [Indexed: 12/14/2022]
Abstract
Cytochrome B is the mitochondrial protein, which functions as part of the electron transport chain and is the main subunit of transmembrane cytochrome bc1 and b6f complexes affecting energy metabolism through oxidative phosphorylation. The present study was conducted to study the effect of mutation of Cytochrome B gene on the health condition of sheep, which the first report of association of mitochondrial gene with disease traits in livestock species. Non-synonymous substitutions (F33 L and D171N) and Indel mutations were observed for Cytochrome B gene, leading to a truncated protein, where anemia, malfunctioning of most of the vital organs as liver, kidney and mineral status was observed and debility with exercise intolerance and cardiomyopathy in extreme cases were depicted. These findings were confirmed by bioinformatics analysis, haematological and biochemical data analysis, and other phenotypical physiological data pertaining to different vital organs. The molecular mechanism of cytochrome B mutation was that the mutant variant interferes with the site of heme binding (iron containing) domain and calcium binding essential for electron transport chain. Mutation at amino acid site 33 is located within transmembrane helix A, a hydrophobic environment at the Qi site and close to heme binding domain, and mutation effects these domain and diseases occur. Thermodynamic stability was also observed to decrease in mutant variant. Sheep Cytochrome B being genetically more similar to the human, it may be used as a model for studying human diseases related to cytochrome B defects. Future prospect of the study includes the therapeutic application of recombinant protein, gene therapy and marker-assisted selection of disease-resistant livestock.
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Affiliation(s)
- Aruna Pal
- West Bengal University of Animal and Fishery Sciences, 37, K.B.Sarani, Kolkata-37, West Bengal, India.
| | - Abantika Pal
- Indian Institute of Technology, Kharagpur, Paschim Medinipur, West Bengal, India
| | - Samiddha Banerjee
- West Bengal University of Animal and Fishery Sciences, 37, K.B.Sarani, Kolkata-37, West Bengal, India
| | - S Batabyal
- West Bengal University of Animal and Fishery Sciences, 37, K.B.Sarani, Kolkata-37, West Bengal, India
| | - P N Chatterjee
- West Bengal University of Animal and Fishery Sciences, 37, K.B.Sarani, Kolkata-37, West Bengal, India
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11
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Abstract
Enzymes are complex biological catalysts and are critical to life. Most oxidations of chemicals are catalyzed by cytochrome P450 (P450, CYP) enzymes, which generally utilize mixed-function oxidase stoichiometry, utilizing pyridine nucleotides as electron donors: NAD(P)H + O2 + R → NAD(P)+ + RO + H2O (where R is a carbon substrate and RO is an oxidized product). The catalysis of oxidations is largely understood in the context of the heme iron-oxygen complex generally referred to as Compound I, formally FeO3+, whose basis was in peroxidase chemistry. Many X-ray crystal structures of P450s are now available (≥ 822 structures from ≥146 different P450s) and have helped in understanding catalytic specificity. In addition to hydroxylations, P450s catalyze more complex oxidations, including C-C bond formation and cleavage. Enzymes derived from P450s by directed evolution can even catalyze more unusual reactions, e.g. cyclopropanation. Current P450 questions under investigation include the potential role of the intermediate Compound 0 (formally FeIII-O2 -) in catalysis of some reactions, the roles of high- and low-spin forms of Compound I, the mechanism of desaturation, the roles of open and closed structures of P450s in catalysis, the extent of processivity in multi-step oxidations, and the role of the accessory protein cytochrome b 5. More global questions include exactly how structure drives function, prediction of catalysis, and roles of multiple protein conformations.
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Affiliation(s)
- F. Peter Guengerich
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146, United States
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12
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Yi-Wen Z, Mei-Hua B, Xiao-Ya L, Yu C, Jing Y, Hong-Hao Z. Effects of Oridonin on Hepatic Cytochrome P450 Expression and Activities in PXR-Humanized Mice. Biol Pharm Bull 2018; 41:707-712. [PMID: 29709908 DOI: 10.1248/bpb.b17-00882] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Indexed: 11/22/2022]
Abstract
Oridonin, the major terpene found in Rabdosia rubescens, is widely used as dietary supplement or therapeutic drug, while the effects of oridonin on CYP450 were still unclear. The pregnane X receptor (PXR) is an important regulatory factor for major drug metabolism enzyme CYPs, and it has been reported to have species-specific differences. Therefore, this study has employed more reliable models PXR-humanized mouse to investigate the influence of oridonin on PXR and downstream metabolism enzyme. Eight-week-old male PXR-humanized mice were treated with oridonin by orally (0, 25, 50, 100, 200 mg/kg) for 15 d. The effects of oridonin on major downstream CYPs of PXR were examined at both the mRNA and enzyme activity levels by RT-PCR and HPLC-MS/MS. In general, there was no significant toxic reaction in liver of PXR-humanized mice. The mRNA expression of CYPs and cytochrome P450 oxidoreductase (POR) were increased with oridonin treatment in a dose-dependent manner. CYP2c and CYP3a family catalytic activity were increased significantly in two higher doses groups. These results indicate that oridonin induced the expression and activation of CYP2c and CYP3a family, which might contribute to potential drug-drug interactions and appear to be a risk when co-administered with other clinical drugs.
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Affiliation(s)
- Zhang Yi-Wen
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University.,Institute of Clinical Pharmacology, Central South University, Hunan Key Laboratory of Pharmacogenetics.,Key Laboratory of Head & Neck Cancer Translational Research of Zhejiang Province, Zhejiang Cancer Hospital
| | - Bao Mei-Hua
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University.,Institute of Clinical Pharmacology, Central South University, Hunan Key Laboratory of Pharmacogenetics.,Department of Anatomy, Histology and Embryology, Changsha Medical University
| | - Lou Xiao-Ya
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University.,Institute of Clinical Pharmacology, Central South University, Hunan Key Laboratory of Pharmacogenetics
| | - Cheng Yu
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University.,Institute of Clinical Pharmacology, Central South University, Hunan Key Laboratory of Pharmacogenetics
| | - Yu Jing
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University.,Institute of Clinical Pharmacology, Central South University, Hunan Key Laboratory of Pharmacogenetics
| | - Zhou Hong-Hao
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University.,Institute of Clinical Pharmacology, Central South University, Hunan Key Laboratory of Pharmacogenetics
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13
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Gentry KA, Zhang M, Im SC, Waskell L, Ramamoorthy A. Substrate mediated redox partner selectivity of cytochrome P450. Chem Commun (Camb) 2018; 54:5780-5783. [PMID: 29781479 DOI: 10.1039/c8cc02525h] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Indexed: 01/30/2023]
Abstract
Investigating the interplay between cytochrome-P450 and its redox partners (CPR and cytochrome-b5) is vital for understanding the metabolism of most hydrophobic drugs. Dynamic structural interactions with the ternary complex, with and without substrates, captured by NMR reveal a gating mechanism for redox partners to promote P450 function.
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Affiliation(s)
- Katherine A Gentry
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA.
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14
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Reed L, Mrizova I, Barta F, Indra R, Moserova M, Kopka K, Schmeiser HH, Wolf CR, Henderson CJ, Stiborova M, Phillips DH, Arlt VM. Cytochrome b 5 impacts on cytochrome P450-mediated metabolism of benzo[a]pyrene and its DNA adduct formation: studies in hepatic cytochrome b 5 /P450 reductase null (HBRN) mice. Arch Toxicol 2018; 92:1625-1638. [PMID: 29368147 PMCID: PMC5882632 DOI: 10.1007/s00204-018-2162-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 09/15/2017] [Accepted: 01/17/2018] [Indexed: 12/17/2022]
Abstract
Benzo[a]pyrene (BaP) is an environmental pollutant that, based on evidence largely from in vitro studies, exerts its genotoxic effects after metabolic activation by cytochrome P450s. In the present study, Hepatic Reductase Null (HRN) and Hepatic Cytochrome b 5 /P450 Reductase Null (HBRN) mice have been used to study the role of P450s in the metabolic activation of BaP in vivo. In HRN mice, cytochrome P450 oxidoreductase (POR), the electron donor to P450, is deleted specifically in hepatocytes. In HBRN mice the microsomal haemoprotein cytochrome b 5 , which can also act as an electron donor from cytochrome b 5 reductase to P450s, is also deleted in the liver. Wild-type (WT), HRN and HBRN mice were treated by i.p. injection with 125 mg/kg body weight BaP for 24 h. Hepatic microsomal fractions were isolated from BaP-treated and untreated mice. In vitro incubations carried out with BaP-pretreated microsomal fractions, BaP and DNA resulted in significantly higher BaP-DNA adduct formation with WT microsomal fractions compared to those from HRN or HBRN mice. Adduct formation (i.e. 10-(deoxyguanosin-N2-yl)-7,8,9-trihydroxy-7,8,9,10-tetrahydro-BaP [dG-N2-BPDE]) correlated with observed CYP1A activity and metabolite formation (i.e. BaP-7,8-dihydrodiol) when NADPH or NADH was used as enzymatic cofactors. BaP-DNA adduct levels (i.e. dG-N2-BPDE) in vivo were significantly higher (~ sevenfold) in liver of HRN mice than WT mice while no significant difference in adduct formation was observed in liver between HBRN and WT mice. Our results demonstrate that POR and cytochrome b 5 both modulate P450-mediated activation of BaP in vitro. However, hepatic P450 enzymes in vivo appear to be more important for BaP detoxification than its activation.
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Affiliation(s)
- Lindsay Reed
- Department of Analytical, Environmental and Forensic Sciences, MRC-PHE Centre for Environment and Health, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 9NH, UK
| | - Iveta Mrizova
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40, Prague 2, Czech Republic
| | - Frantisek Barta
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40, Prague 2, Czech Republic
| | - Radek Indra
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40, Prague 2, Czech Republic
| | - Michaela Moserova
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40, Prague 2, Czech Republic
| | - Klaus Kopka
- Division of Radiopharmaceutical Chemistry, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
| | - Heinz H Schmeiser
- Division of Radiopharmaceutical Chemistry, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
| | - C Roland Wolf
- Division of Cancer Research, Jacqui Wood Cancer Centre, School of Medicine, University of Dundee, Ninewells Hospital, Dundee, DD1 9SY, UK
| | - Colin J Henderson
- Division of Cancer Research, Jacqui Wood Cancer Centre, School of Medicine, University of Dundee, Ninewells Hospital, Dundee, DD1 9SY, UK
| | - Marie Stiborova
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40, Prague 2, Czech Republic
| | - David H Phillips
- Department of Analytical, Environmental and Forensic Sciences, MRC-PHE Centre for Environment and Health, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 9NH, UK
| | - Volker M Arlt
- Department of Analytical, Environmental and Forensic Sciences, MRC-PHE Centre for Environment and Health, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 9NH, UK.
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15
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Gentry KA, Prade E, Barnaba C, Zhang M, Mahajan M, Im SC, Anantharamaiah GM, Nagao S, Waskell L, Ramamoorthy A. Kinetic and Structural Characterization of the Effects of Membrane on the Complex of Cytochrome b 5 and Cytochrome c. Sci Rep 2017; 7:7793. [PMID: 28798301 PMCID: PMC5552742 DOI: 10.1038/s41598-017-08130-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 06/06/2017] [Accepted: 07/04/2017] [Indexed: 12/13/2022] Open
Abstract
Cytochrome b5 (cytb5) is a membrane protein vital for the regulation of cytochrome P450 (cytP450) metabolism and is capable of electron transfer to many redox partners. Here, using cyt c as a surrogate for cytP450, we report the effect of membrane on the interaction between full-length cytb5 and cyt c for the first time. As shown through stopped-flow kinetic experiments, electron transfer capable cytb5 - cyt c complexes were formed in the presence of bicelles and nanodiscs. Experimentally measured NMR parameters were used to map the cytb5-cyt c binding interface. Our experimental results identify differences in the binding epitope of cytb5 in the presence and absence of membrane. Notably, in the presence of membrane, cytb5 only engaged cyt c at its lower and upper clefts while the membrane-free cytb5 also uses a distal region. Using restraints generated from both cytb5 and cyt c, a complex structure was generated and a potential electron transfer pathway was identified. These results demonstrate the importance of studying protein-protein complex formation in membrane mimetic systems. Our results also demonstrate the successful preparation of novel peptide-based lipid nanodiscs, which are detergent-free and possesses size flexibility, and their use for NMR structural studies of membrane proteins.
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Affiliation(s)
| | - Elke Prade
- Biophysics Program, University of Michigan, Ann Arbor, MI, 48109, USA.,Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Carlo Barnaba
- Biophysics Program, University of Michigan, Ann Arbor, MI, 48109, USA.,Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Meng Zhang
- Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Mukesh Mahajan
- Biophysics Program, University of Michigan, Ann Arbor, MI, 48109, USA.,Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Sang-Choul Im
- Department of Anesthesiology, University of Michigan, and Veterans Affairs Medical Center, Ann Arbor, Michigan, 48105, USA
| | - G M Anantharamaiah
- Department of Medicine, UAB Medical Center, Birmingham, Alabama, 35294, USA
| | - Satoshi Nagao
- Graduate School of Material Science, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara, 630-0192, Japan
| | - Lucy Waskell
- Department of Anesthesiology, University of Michigan, and Veterans Affairs Medical Center, Ann Arbor, Michigan, 48105, USA
| | - Ayyalusamy Ramamoorthy
- Biophysics Program, University of Michigan, Ann Arbor, MI, 48109, USA. .,Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA.
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16
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Stiborová M, Indra R, Frei E, Kopečková K, Schmeiser HH, Eckschlager T, Adam V, Heger Z, Arlt VM, Martínek V. Cytochrome b5 plays a dual role in the reaction cycle of cytochrome P450 3A4 during oxidation of the anticancer drug ellipticine. MONATSHEFTE FUR CHEMIE 2017; 148:1983-1991. [PMID: 29104319 PMCID: PMC5653753 DOI: 10.1007/s00706-017-1986-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Academic Contribution Register] [Received: 03/08/2017] [Accepted: 04/13/2017] [Indexed: 12/18/2022]
Abstract
Abstract Ellipticine is an anticancer agent that forms covalent DNA adducts after enzymatic activation by cytochrome P450 (CYP) enzymes, mainly by CYP3A4. This process is one of the most important ellipticine DNA-damaging mechanisms for its antitumor action. Here, we investigated the efficiencies of human hepatic microsomes and human recombinant CYP3A4 expressed with its reductase, NADPH:CYP oxidoreductase (POR), NADH:cytochrome b5 reductase and/or cytochrome b5 in Supersomes™ to oxidize this drug. We also evaluated the effectiveness of coenzymes of two of the microsomal reductases, NADPH as a coenzyme of POR, and NADH as a coenzyme of NADH:cytochrome b5 reductase, to mediate ellipticine oxidation in these enzyme systems. Using HPLC analysis we detected up to five ellipticine metabolites, which were formed by human hepatic microsomes and human CYP3A4 in the presence of NADPH or NADH. Among ellipticine metabolites, 9-hydroxy-, 12-hydroxy-, and 13-hydroxyellipticine were formed by hepatic microsomes as the major metabolites, while 7-hydroxyellipticine and the ellipticine N2-oxide were the minor ones. Human CYP3A4 in Supersomes™ generated only three metabolic products, 9-hydroxy-, 12-hydroxy-, and 13-hydroxyellipticine. Using the 32P-postlabeling method two ellipticine-derived DNA adducts were generated by microsomes and the CYP3A4-Supersome system, both in the presence of NADPH and NADH. These adducts were derived from the reaction of 13-hydroxy- and 12-hydroxyellipticine with deoxyguanosine in DNA. In the presence of NADPH or NADH, cytochrome b5 stimulated the CYP3A4-mediated oxidation of ellipticine, but the stimulation effect differed for individual ellipticine metabolites. This heme protein also stimulated the formation of both ellipticine-DNA adducts. The results demonstrate that cytochrome b5 plays a dual role in the CYP3A4-catalyzed oxidation of ellipticine: (1) cytochrome b5 mediates CYP3A4 catalytic activities by donating the first and second electron to this enzyme in its catalytic cycle, indicating that NADH:cytochrome b5 reductase can substitute NADPH-dependent POR in this enzymatic reaction and (2) cytochrome b5 can act as an allosteric modifier of the CYP3A4 oxygenase. Graphical abstract ![]()
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Affiliation(s)
- Marie Stiborová
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 Prague 2, Czech Republic
| | - Radek Indra
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 Prague 2, Czech Republic
| | - Eva Frei
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 Prague 2, Czech Republic
| | - Kateřina Kopečková
- Department of Oncology, 2nd Faculty of Medicine, Charles University and University Hospital Motol, V Uvalu 84, 150 06 Prague 5, Czech Republic
| | - Heinz H Schmeiser
- Division of Radiopharmaceutical Chemistry, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Tomáš Eckschlager
- Department of Pediatric Hematology and Oncology, 2nd Medical Faculty, Charles University and University Hospital Motol, V Uvalu 84, 150 06 Prague 5, Czech Republic
| | - Vojtěch Adam
- Laboratory of Metallomics and Nanotechnology, Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, 61300 Brno, Czech Republic
| | - Zbyněk Heger
- Laboratory of Metallomics and Nanotechnology, Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, 61300 Brno, Czech Republic
| | - Volker M Arlt
- Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment and Health, King's College London, London, SE1 9NH UK
| | - Václav Martínek
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 Prague 2, Czech Republic
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17
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Bhatt MR, Khatri Y, Rodgers RJ, Martin LL. Role of cytochrome b5 in the modulation of the enzymatic activities of cytochrome P450 17α-hydroxylase/17,20-lyase (P450 17A1). J Steroid Biochem Mol Biol 2017; 170:2-18. [PMID: 26976652 DOI: 10.1016/j.jsbmb.2016.02.033] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Academic Contribution Register] [Received: 11/23/2015] [Revised: 02/25/2016] [Accepted: 02/27/2016] [Indexed: 12/13/2022]
Abstract
Cytochrome b5 (cyt b5) is a small hemoprotein that plays a significant role in the modulation of activities of an important steroidogenic enzyme, cytochrome P450 17α-hydroxylase/17,20-lyase (P450 17A1, CYP17A1). Located in the zona fasciculata and zona reticularis of the adrenal cortex and in the gonads, P450 17A1 catalyzes two different reactions in the steroidogenic pathway; the 17α-hydroxylation and 17,20-lyase, in the endoplasmic reticulum of these respective tissues. The activities of P450 17A1 are regulated by cyt b5 that enhances the 17,20-lyase reaction by promoting the coupling of P450 17A1 and cytochrome P450 reductase (CPR), allosterically. Cyt b5 can also act as an electron donor to enhance the 16-ene-synthase activity of human P450 17A1. In this review, we discuss the many roles of cyt b5 and focus on the modulation of CYP17A1 activities by cyt b5 and the mechanisms involved.
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Affiliation(s)
- Megh Raj Bhatt
- Everest Biotech Pvt. Ltd., Khumaltar, Lalitpur, P.O. Box 21608, Kathmandu 44600, Nepal
| | - Yogan Khatri
- Institute of Biochemistry, Saarland University, 66123 Saarbrücken, Germany
| | - Raymond J Rodgers
- School of Medicine, Robinson Research Institute, University of Adelaide, Adelaide SA 5005, Australia
| | - Lisandra L Martin
- School of Chemistry, Monash University, Clayton, 3800, Victoria, Australia.
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18
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Stiborová M, Indra R, Moserová M, Frei E, Schmeiser HH, Kopka K, Philips DH, Arlt V. NADH:Cytochrome b5 Reductase and Cytochrome b5 Can Act as Sole Electron Donors to Human Cytochrome P450 1A1-Mediated Oxidation and DNA Adduct Formation by Benzo[a]pyrene. Chem Res Toxicol 2016; 29:1325-34. [PMID: 27404282 PMCID: PMC4987862 DOI: 10.1021/acs.chemrestox.6b00143] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 04/28/2016] [Indexed: 11/29/2022]
Abstract
Benzo[a]pyrene (BaP) is a human carcinogen that covalently binds to DNA after activation by cytochrome P450 (P450). Here, we investigated whether NADH:cytochrome b5 reductase (CBR) in the presence of cytochrome b5 can act as sole electron donor to human P450 1A1 during BaP oxidation and replace the canonical NADPH:cytochrome P450 reductase (POR) system. We also studied the efficiencies of the coenzymes of these reductases, NADPH as a coenzyme of POR, and NADH as a coenzyme of CBR, to mediate BaP oxidation. Two systems containing human P450 1A1 were utilized: human recombinant P450 1A1 expressed with POR, CBR, epoxide hydrolase, and cytochrome b5 in Supersomes and human recombinant P450 1A1 reconstituted with POR and/or with CBR and cytochrome b5 in liposomes. BaP-9,10-dihydrodiol, BaP-7,8-dihydrodiol, BaP-1,6-dione, BaP-3,6-dione, BaP-9-ol, BaP-3-ol, a metabolite of unknown structure, and two BaP-DNA adducts were generated by the P450 1A1-Supersomes system, both in the presence of NADPH and in the presence of NADH. The major BaP-DNA adduct detected by (32)P-postlabeling was characterized as 10-(deoxyguanosin-N(2)-yl)-7,8,9-trihydroxy-7,8,9,10-tetrahydro-BaP (assigned adduct 1), while the minor adduct is probably a guanine adduct derived from 9-hydroxy-BaP-4,5-epoxide (assigned adduct 2). BaP-3-ol as the major metabolite, BaP-9-ol, BaP-1,6-dione, BaP-3,6-dione, an unknown metabolite, and adduct 2 were observed in the system using P450 1A1 reconstituted with POR plus NADPH. When P450 1A1 was reconstituted with CBR and cytochrome b5 plus NADH, BaP-3-ol was the predominant metabolite too, and an adduct 2 was also generated. Our results demonstrate that the NADH/cytochrome b5/CBR system can act as the sole electron donor both for the first and second reduction of P450 1A1 during the oxidation of BaP in vitro. They suggest that NADH-dependent CBR can replace NADPH-dependent POR in the P450 1A1-catalyzed metabolism of BaP.
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Affiliation(s)
- Marie Stiborová
- Department
of Biochemistry, Faculty of Science, Charles
University, Albertov
2030, 128 40, Prague 2, Czech
Republic
| | - Radek Indra
- Department
of Biochemistry, Faculty of Science, Charles
University, Albertov
2030, 128 40, Prague 2, Czech
Republic
| | - Michaela Moserová
- Department
of Biochemistry, Faculty of Science, Charles
University, Albertov
2030, 128 40, Prague 2, Czech
Republic
| | - Eva Frei
- Department
of Biochemistry, Faculty of Science, Charles
University, Albertov
2030, 128 40, Prague 2, Czech
Republic
| | - Heinz H. Schmeiser
- Division
of Radiopharmaceutical Chemistry, German
Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Klaus Kopka
- Department
of Biochemistry, Faculty of Science, Charles
University, Albertov
2030, 128 40, Prague 2, Czech
Republic
| | - David H. Philips
- Analytical
and Environmental Sciences Division, MRC-PHE Centre for Environment
and Health, King’s College London, Franklin-Wilkins Building, 150 Stamford
Street, London SE1 9NH, United Kingdom
- NIHR
Health Protection Research Unit in Health Impact of Environmental
Hazards at King’s College London in Partnership with Public
Health England, Franklin-Wilkins
Building, 150 Stamford Street, London SE1 9NH, United Kingdom
| | - Volker
M. Arlt
- Analytical
and Environmental Sciences Division, MRC-PHE Centre for Environment
and Health, King’s College London, Franklin-Wilkins Building, 150 Stamford
Street, London SE1 9NH, United Kingdom
- NIHR
Health Protection Research Unit in Health Impact of Environmental
Hazards at King’s College London in Partnership with Public
Health England, Franklin-Wilkins
Building, 150 Stamford Street, London SE1 9NH, United Kingdom
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19
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Scott EE, Wolf CR, Otyepka M, Humphreys SC, Reed JR, Henderson CJ, McLaughlin LA, Paloncýová M, Navrátilová V, Berka K, Anzenbacher P, Dahal UP, Barnaba C, Brozik JA, Jones JP, Estrada DF, Laurence JS, Park JW, Backes WL. The Role of Protein-Protein and Protein-Membrane Interactions on P450 Function. Drug Metab Dispos 2016; 44:576-90. [PMID: 26851242 PMCID: PMC4810767 DOI: 10.1124/dmd.115.068569] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 12/29/2015] [Accepted: 02/03/2016] [Indexed: 11/22/2022] Open
Abstract
This symposium summary, sponsored by the ASPET, was held at Experimental Biology 2015 on March 29, 2015, in Boston, Massachusetts. The symposium focused on: 1) the interactions of cytochrome P450s (P450s) with their redox partners; and 2) the role of the lipid membrane in their orientation and stabilization. Two presentations discussed the interactions of P450s with NADPH-P450 reductase (CPR) and cytochrome b5. First, solution nuclear magnetic resonance was used to compare the protein interactions that facilitated either the hydroxylase or lyase activities of CYP17A1. The lyase interaction was stimulated by the presence of b5 and 17α-hydroxypregnenolone, whereas the hydroxylase reaction was predominant in the absence of b5. The role of b5 was also shown in vivo by selective hepatic knockout of b5 from mice expressing CYP3A4 and CYP2D6; the lack of b5 caused a decrease in the clearance of several substrates. The role of the membrane on P450 orientation was examined using computational methods, showing that the proximal region of the P450 molecule faced the aqueous phase. The distal region, containing the substrate-access channel, was associated with the membrane. The interaction of NADPH-P450 reductase (CPR) with the membrane was also described, showing the ability of CPR to "helicopter" above the membrane. Finally, the endoplasmic reticulum (ER) was shown to be heterogeneous, having ordered membrane regions containing cholesterol and more disordered regions. Interestingly, two closely related P450s, CYP1A1 and CYP1A2, resided in different regions of the ER. The structural characteristics of their localization were examined. These studies emphasize the importance of P450 protein organization to their function.
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Affiliation(s)
- Emily E Scott
- Departments of Medicinal Chemistry and Pharmaceutical Chemistry, The University of Kansas, Lawrence, Kansas (D.F.E, J.S.L., E.E.S.); Division of Cancer Research, School of Medicine, University of Dundee, Ninewells Hospital, Dundee, United Kingdom (C.R.W., C.J.H., L.A.M.); Regional Center of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science (M.O., M.P., V.N., K.B.) and Department of Pharmacology, Faculty of Medicine and Dentistry (P.A.), Palacký University, Olomouc, Czech Republic; Department of Chemistry, Washington State University, Pullman, Washington (S.C.H., U.P.D., C.B., J.A.B., J.P.J.); and Department of Pharmacology and Experimental Therapeutics, and the Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, New Orleans, Louisiana (J.R.R., J.W.P., W.L.B.)
| | - C Roland Wolf
- Departments of Medicinal Chemistry and Pharmaceutical Chemistry, The University of Kansas, Lawrence, Kansas (D.F.E, J.S.L., E.E.S.); Division of Cancer Research, School of Medicine, University of Dundee, Ninewells Hospital, Dundee, United Kingdom (C.R.W., C.J.H., L.A.M.); Regional Center of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science (M.O., M.P., V.N., K.B.) and Department of Pharmacology, Faculty of Medicine and Dentistry (P.A.), Palacký University, Olomouc, Czech Republic; Department of Chemistry, Washington State University, Pullman, Washington (S.C.H., U.P.D., C.B., J.A.B., J.P.J.); and Department of Pharmacology and Experimental Therapeutics, and the Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, New Orleans, Louisiana (J.R.R., J.W.P., W.L.B.)
| | - Michal Otyepka
- Departments of Medicinal Chemistry and Pharmaceutical Chemistry, The University of Kansas, Lawrence, Kansas (D.F.E, J.S.L., E.E.S.); Division of Cancer Research, School of Medicine, University of Dundee, Ninewells Hospital, Dundee, United Kingdom (C.R.W., C.J.H., L.A.M.); Regional Center of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science (M.O., M.P., V.N., K.B.) and Department of Pharmacology, Faculty of Medicine and Dentistry (P.A.), Palacký University, Olomouc, Czech Republic; Department of Chemistry, Washington State University, Pullman, Washington (S.C.H., U.P.D., C.B., J.A.B., J.P.J.); and Department of Pharmacology and Experimental Therapeutics, and the Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, New Orleans, Louisiana (J.R.R., J.W.P., W.L.B.)
| | - Sara C Humphreys
- Departments of Medicinal Chemistry and Pharmaceutical Chemistry, The University of Kansas, Lawrence, Kansas (D.F.E, J.S.L., E.E.S.); Division of Cancer Research, School of Medicine, University of Dundee, Ninewells Hospital, Dundee, United Kingdom (C.R.W., C.J.H., L.A.M.); Regional Center of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science (M.O., M.P., V.N., K.B.) and Department of Pharmacology, Faculty of Medicine and Dentistry (P.A.), Palacký University, Olomouc, Czech Republic; Department of Chemistry, Washington State University, Pullman, Washington (S.C.H., U.P.D., C.B., J.A.B., J.P.J.); and Department of Pharmacology and Experimental Therapeutics, and the Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, New Orleans, Louisiana (J.R.R., J.W.P., W.L.B.)
| | - James R Reed
- Departments of Medicinal Chemistry and Pharmaceutical Chemistry, The University of Kansas, Lawrence, Kansas (D.F.E, J.S.L., E.E.S.); Division of Cancer Research, School of Medicine, University of Dundee, Ninewells Hospital, Dundee, United Kingdom (C.R.W., C.J.H., L.A.M.); Regional Center of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science (M.O., M.P., V.N., K.B.) and Department of Pharmacology, Faculty of Medicine and Dentistry (P.A.), Palacký University, Olomouc, Czech Republic; Department of Chemistry, Washington State University, Pullman, Washington (S.C.H., U.P.D., C.B., J.A.B., J.P.J.); and Department of Pharmacology and Experimental Therapeutics, and the Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, New Orleans, Louisiana (J.R.R., J.W.P., W.L.B.)
| | - Colin J Henderson
- Departments of Medicinal Chemistry and Pharmaceutical Chemistry, The University of Kansas, Lawrence, Kansas (D.F.E, J.S.L., E.E.S.); Division of Cancer Research, School of Medicine, University of Dundee, Ninewells Hospital, Dundee, United Kingdom (C.R.W., C.J.H., L.A.M.); Regional Center of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science (M.O., M.P., V.N., K.B.) and Department of Pharmacology, Faculty of Medicine and Dentistry (P.A.), Palacký University, Olomouc, Czech Republic; Department of Chemistry, Washington State University, Pullman, Washington (S.C.H., U.P.D., C.B., J.A.B., J.P.J.); and Department of Pharmacology and Experimental Therapeutics, and the Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, New Orleans, Louisiana (J.R.R., J.W.P., W.L.B.)
| | - Lesley A McLaughlin
- Departments of Medicinal Chemistry and Pharmaceutical Chemistry, The University of Kansas, Lawrence, Kansas (D.F.E, J.S.L., E.E.S.); Division of Cancer Research, School of Medicine, University of Dundee, Ninewells Hospital, Dundee, United Kingdom (C.R.W., C.J.H., L.A.M.); Regional Center of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science (M.O., M.P., V.N., K.B.) and Department of Pharmacology, Faculty of Medicine and Dentistry (P.A.), Palacký University, Olomouc, Czech Republic; Department of Chemistry, Washington State University, Pullman, Washington (S.C.H., U.P.D., C.B., J.A.B., J.P.J.); and Department of Pharmacology and Experimental Therapeutics, and the Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, New Orleans, Louisiana (J.R.R., J.W.P., W.L.B.)
| | - Markéta Paloncýová
- Departments of Medicinal Chemistry and Pharmaceutical Chemistry, The University of Kansas, Lawrence, Kansas (D.F.E, J.S.L., E.E.S.); Division of Cancer Research, School of Medicine, University of Dundee, Ninewells Hospital, Dundee, United Kingdom (C.R.W., C.J.H., L.A.M.); Regional Center of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science (M.O., M.P., V.N., K.B.) and Department of Pharmacology, Faculty of Medicine and Dentistry (P.A.), Palacký University, Olomouc, Czech Republic; Department of Chemistry, Washington State University, Pullman, Washington (S.C.H., U.P.D., C.B., J.A.B., J.P.J.); and Department of Pharmacology and Experimental Therapeutics, and the Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, New Orleans, Louisiana (J.R.R., J.W.P., W.L.B.)
| | - Veronika Navrátilová
- Departments of Medicinal Chemistry and Pharmaceutical Chemistry, The University of Kansas, Lawrence, Kansas (D.F.E, J.S.L., E.E.S.); Division of Cancer Research, School of Medicine, University of Dundee, Ninewells Hospital, Dundee, United Kingdom (C.R.W., C.J.H., L.A.M.); Regional Center of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science (M.O., M.P., V.N., K.B.) and Department of Pharmacology, Faculty of Medicine and Dentistry (P.A.), Palacký University, Olomouc, Czech Republic; Department of Chemistry, Washington State University, Pullman, Washington (S.C.H., U.P.D., C.B., J.A.B., J.P.J.); and Department of Pharmacology and Experimental Therapeutics, and the Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, New Orleans, Louisiana (J.R.R., J.W.P., W.L.B.)
| | - Karel Berka
- Departments of Medicinal Chemistry and Pharmaceutical Chemistry, The University of Kansas, Lawrence, Kansas (D.F.E, J.S.L., E.E.S.); Division of Cancer Research, School of Medicine, University of Dundee, Ninewells Hospital, Dundee, United Kingdom (C.R.W., C.J.H., L.A.M.); Regional Center of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science (M.O., M.P., V.N., K.B.) and Department of Pharmacology, Faculty of Medicine and Dentistry (P.A.), Palacký University, Olomouc, Czech Republic; Department of Chemistry, Washington State University, Pullman, Washington (S.C.H., U.P.D., C.B., J.A.B., J.P.J.); and Department of Pharmacology and Experimental Therapeutics, and the Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, New Orleans, Louisiana (J.R.R., J.W.P., W.L.B.)
| | - Pavel Anzenbacher
- Departments of Medicinal Chemistry and Pharmaceutical Chemistry, The University of Kansas, Lawrence, Kansas (D.F.E, J.S.L., E.E.S.); Division of Cancer Research, School of Medicine, University of Dundee, Ninewells Hospital, Dundee, United Kingdom (C.R.W., C.J.H., L.A.M.); Regional Center of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science (M.O., M.P., V.N., K.B.) and Department of Pharmacology, Faculty of Medicine and Dentistry (P.A.), Palacký University, Olomouc, Czech Republic; Department of Chemistry, Washington State University, Pullman, Washington (S.C.H., U.P.D., C.B., J.A.B., J.P.J.); and Department of Pharmacology and Experimental Therapeutics, and the Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, New Orleans, Louisiana (J.R.R., J.W.P., W.L.B.)
| | - Upendra P Dahal
- Departments of Medicinal Chemistry and Pharmaceutical Chemistry, The University of Kansas, Lawrence, Kansas (D.F.E, J.S.L., E.E.S.); Division of Cancer Research, School of Medicine, University of Dundee, Ninewells Hospital, Dundee, United Kingdom (C.R.W., C.J.H., L.A.M.); Regional Center of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science (M.O., M.P., V.N., K.B.) and Department of Pharmacology, Faculty of Medicine and Dentistry (P.A.), Palacký University, Olomouc, Czech Republic; Department of Chemistry, Washington State University, Pullman, Washington (S.C.H., U.P.D., C.B., J.A.B., J.P.J.); and Department of Pharmacology and Experimental Therapeutics, and the Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, New Orleans, Louisiana (J.R.R., J.W.P., W.L.B.)
| | - Carlo Barnaba
- Departments of Medicinal Chemistry and Pharmaceutical Chemistry, The University of Kansas, Lawrence, Kansas (D.F.E, J.S.L., E.E.S.); Division of Cancer Research, School of Medicine, University of Dundee, Ninewells Hospital, Dundee, United Kingdom (C.R.W., C.J.H., L.A.M.); Regional Center of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science (M.O., M.P., V.N., K.B.) and Department of Pharmacology, Faculty of Medicine and Dentistry (P.A.), Palacký University, Olomouc, Czech Republic; Department of Chemistry, Washington State University, Pullman, Washington (S.C.H., U.P.D., C.B., J.A.B., J.P.J.); and Department of Pharmacology and Experimental Therapeutics, and the Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, New Orleans, Louisiana (J.R.R., J.W.P., W.L.B.)
| | - James A Brozik
- Departments of Medicinal Chemistry and Pharmaceutical Chemistry, The University of Kansas, Lawrence, Kansas (D.F.E, J.S.L., E.E.S.); Division of Cancer Research, School of Medicine, University of Dundee, Ninewells Hospital, Dundee, United Kingdom (C.R.W., C.J.H., L.A.M.); Regional Center of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science (M.O., M.P., V.N., K.B.) and Department of Pharmacology, Faculty of Medicine and Dentistry (P.A.), Palacký University, Olomouc, Czech Republic; Department of Chemistry, Washington State University, Pullman, Washington (S.C.H., U.P.D., C.B., J.A.B., J.P.J.); and Department of Pharmacology and Experimental Therapeutics, and the Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, New Orleans, Louisiana (J.R.R., J.W.P., W.L.B.)
| | - Jeffrey P Jones
- Departments of Medicinal Chemistry and Pharmaceutical Chemistry, The University of Kansas, Lawrence, Kansas (D.F.E, J.S.L., E.E.S.); Division of Cancer Research, School of Medicine, University of Dundee, Ninewells Hospital, Dundee, United Kingdom (C.R.W., C.J.H., L.A.M.); Regional Center of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science (M.O., M.P., V.N., K.B.) and Department of Pharmacology, Faculty of Medicine and Dentistry (P.A.), Palacký University, Olomouc, Czech Republic; Department of Chemistry, Washington State University, Pullman, Washington (S.C.H., U.P.D., C.B., J.A.B., J.P.J.); and Department of Pharmacology and Experimental Therapeutics, and the Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, New Orleans, Louisiana (J.R.R., J.W.P., W.L.B.)
| | - D Fernando Estrada
- Departments of Medicinal Chemistry and Pharmaceutical Chemistry, The University of Kansas, Lawrence, Kansas (D.F.E, J.S.L., E.E.S.); Division of Cancer Research, School of Medicine, University of Dundee, Ninewells Hospital, Dundee, United Kingdom (C.R.W., C.J.H., L.A.M.); Regional Center of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science (M.O., M.P., V.N., K.B.) and Department of Pharmacology, Faculty of Medicine and Dentistry (P.A.), Palacký University, Olomouc, Czech Republic; Department of Chemistry, Washington State University, Pullman, Washington (S.C.H., U.P.D., C.B., J.A.B., J.P.J.); and Department of Pharmacology and Experimental Therapeutics, and the Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, New Orleans, Louisiana (J.R.R., J.W.P., W.L.B.)
| | - Jennifer S Laurence
- Departments of Medicinal Chemistry and Pharmaceutical Chemistry, The University of Kansas, Lawrence, Kansas (D.F.E, J.S.L., E.E.S.); Division of Cancer Research, School of Medicine, University of Dundee, Ninewells Hospital, Dundee, United Kingdom (C.R.W., C.J.H., L.A.M.); Regional Center of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science (M.O., M.P., V.N., K.B.) and Department of Pharmacology, Faculty of Medicine and Dentistry (P.A.), Palacký University, Olomouc, Czech Republic; Department of Chemistry, Washington State University, Pullman, Washington (S.C.H., U.P.D., C.B., J.A.B., J.P.J.); and Department of Pharmacology and Experimental Therapeutics, and the Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, New Orleans, Louisiana (J.R.R., J.W.P., W.L.B.)
| | - Ji Won Park
- Departments of Medicinal Chemistry and Pharmaceutical Chemistry, The University of Kansas, Lawrence, Kansas (D.F.E, J.S.L., E.E.S.); Division of Cancer Research, School of Medicine, University of Dundee, Ninewells Hospital, Dundee, United Kingdom (C.R.W., C.J.H., L.A.M.); Regional Center of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science (M.O., M.P., V.N., K.B.) and Department of Pharmacology, Faculty of Medicine and Dentistry (P.A.), Palacký University, Olomouc, Czech Republic; Department of Chemistry, Washington State University, Pullman, Washington (S.C.H., U.P.D., C.B., J.A.B., J.P.J.); and Department of Pharmacology and Experimental Therapeutics, and the Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, New Orleans, Louisiana (J.R.R., J.W.P., W.L.B.)
| | - Wayne L Backes
- Departments of Medicinal Chemistry and Pharmaceutical Chemistry, The University of Kansas, Lawrence, Kansas (D.F.E, J.S.L., E.E.S.); Division of Cancer Research, School of Medicine, University of Dundee, Ninewells Hospital, Dundee, United Kingdom (C.R.W., C.J.H., L.A.M.); Regional Center of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science (M.O., M.P., V.N., K.B.) and Department of Pharmacology, Faculty of Medicine and Dentistry (P.A.), Palacký University, Olomouc, Czech Republic; Department of Chemistry, Washington State University, Pullman, Washington (S.C.H., U.P.D., C.B., J.A.B., J.P.J.); and Department of Pharmacology and Experimental Therapeutics, and the Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, New Orleans, Louisiana (J.R.R., J.W.P., W.L.B.)
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Sondhi V, Owen BM, Liu J, Chomic R, Kliewer SA, Hughes BA, Arlt W, Mangelsdorf DJ, Auchus RJ. Impaired 17,20-Lyase Activity in Male Mice Lacking Cytochrome b5 in Leydig Cells. Mol Endocrinol 2016; 30:469-78. [PMID: 26974035 PMCID: PMC4814474 DOI: 10.1210/me.2015-1282] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Academic Contribution Register] [Indexed: 02/08/2023] Open
Abstract
Androgen and estrogen biosynthesis in mammals requires the 17,20-lyase activity of cytochrome P450 17A1 (steroid 17-hydroxylase/17,20-lyase). Maximal 17,20-lyase activity in vitro requires the presence of cytochrome b5 (b5), and rare cases of b5 deficiency in human beings causes isolated 17,20-lyase deficiency. To study the consequences of conditional b5 removal from testicular Leydig cells in an animal model, we generated Cyb5flox/flox:Sf1-Cre (LeyKO) mice. The LeyKO male mice had normal body weights, testis and sex organ weights, and fertility compared with littermates. Basal serum and urine steroid profiles of LeyKO males were not significantly different than littermates. In contrast, marked 17-hydroxyprogesterone accumulation (100-fold basal) and reduced testosterone synthesis (27% of littermates) were observed after human chorionic gonadotropin stimulation in LeyKO animals. Testis homogenates from LeyKO mice showed reduced 17,20-lyase activity and a 3-fold increased 17-hydroxylase to 17,20-lyase activity ratio, which were restored to normal upon addition of recombinant b5. We conclude that Leydig cell b5 is required for maximal androgen synthesis and to prevent 17-hydroxyprogesterone accumulation in the mouse testis; however, the b5-independent 17,20-lyase activity of mouse steroid 17-hydroxylase/17,20-lyase is sufficient for normal male genital development and fertility. LeyKO male mice are a good model for the biochemistry but not the physiology of isolated 17,20-lyase deficiency in human beings.
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Affiliation(s)
- Varun Sondhi
- Departments of Pharmacology (V.S., B.M.O., S.A.K., D.J.M.) and Molecular Biology (S.A.K.) and the Howard Hughes Medical Institute (D.J.M.), University of Texas Southwestern Medical Center, Dallas, Texas 75390; Departments of Internal Medicine and Pharmacology (J.L., R.J.A.) and the Michigan Metabolomics and Obesity Center (R.C.), University of Michigan, Ann Arbor, Michigan 48109; and the Institute of Metabolism and Systems Research (B.A.H., W.A.), University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Bryn M Owen
- Departments of Pharmacology (V.S., B.M.O., S.A.K., D.J.M.) and Molecular Biology (S.A.K.) and the Howard Hughes Medical Institute (D.J.M.), University of Texas Southwestern Medical Center, Dallas, Texas 75390; Departments of Internal Medicine and Pharmacology (J.L., R.J.A.) and the Michigan Metabolomics and Obesity Center (R.C.), University of Michigan, Ann Arbor, Michigan 48109; and the Institute of Metabolism and Systems Research (B.A.H., W.A.), University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Jiayan Liu
- Departments of Pharmacology (V.S., B.M.O., S.A.K., D.J.M.) and Molecular Biology (S.A.K.) and the Howard Hughes Medical Institute (D.J.M.), University of Texas Southwestern Medical Center, Dallas, Texas 75390; Departments of Internal Medicine and Pharmacology (J.L., R.J.A.) and the Michigan Metabolomics and Obesity Center (R.C.), University of Michigan, Ann Arbor, Michigan 48109; and the Institute of Metabolism and Systems Research (B.A.H., W.A.), University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Robert Chomic
- Departments of Pharmacology (V.S., B.M.O., S.A.K., D.J.M.) and Molecular Biology (S.A.K.) and the Howard Hughes Medical Institute (D.J.M.), University of Texas Southwestern Medical Center, Dallas, Texas 75390; Departments of Internal Medicine and Pharmacology (J.L., R.J.A.) and the Michigan Metabolomics and Obesity Center (R.C.), University of Michigan, Ann Arbor, Michigan 48109; and the Institute of Metabolism and Systems Research (B.A.H., W.A.), University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Steven A Kliewer
- Departments of Pharmacology (V.S., B.M.O., S.A.K., D.J.M.) and Molecular Biology (S.A.K.) and the Howard Hughes Medical Institute (D.J.M.), University of Texas Southwestern Medical Center, Dallas, Texas 75390; Departments of Internal Medicine and Pharmacology (J.L., R.J.A.) and the Michigan Metabolomics and Obesity Center (R.C.), University of Michigan, Ann Arbor, Michigan 48109; and the Institute of Metabolism and Systems Research (B.A.H., W.A.), University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Beverly A Hughes
- Departments of Pharmacology (V.S., B.M.O., S.A.K., D.J.M.) and Molecular Biology (S.A.K.) and the Howard Hughes Medical Institute (D.J.M.), University of Texas Southwestern Medical Center, Dallas, Texas 75390; Departments of Internal Medicine and Pharmacology (J.L., R.J.A.) and the Michigan Metabolomics and Obesity Center (R.C.), University of Michigan, Ann Arbor, Michigan 48109; and the Institute of Metabolism and Systems Research (B.A.H., W.A.), University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Wiebke Arlt
- Departments of Pharmacology (V.S., B.M.O., S.A.K., D.J.M.) and Molecular Biology (S.A.K.) and the Howard Hughes Medical Institute (D.J.M.), University of Texas Southwestern Medical Center, Dallas, Texas 75390; Departments of Internal Medicine and Pharmacology (J.L., R.J.A.) and the Michigan Metabolomics and Obesity Center (R.C.), University of Michigan, Ann Arbor, Michigan 48109; and the Institute of Metabolism and Systems Research (B.A.H., W.A.), University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - David J Mangelsdorf
- Departments of Pharmacology (V.S., B.M.O., S.A.K., D.J.M.) and Molecular Biology (S.A.K.) and the Howard Hughes Medical Institute (D.J.M.), University of Texas Southwestern Medical Center, Dallas, Texas 75390; Departments of Internal Medicine and Pharmacology (J.L., R.J.A.) and the Michigan Metabolomics and Obesity Center (R.C.), University of Michigan, Ann Arbor, Michigan 48109; and the Institute of Metabolism and Systems Research (B.A.H., W.A.), University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Richard J Auchus
- Departments of Pharmacology (V.S., B.M.O., S.A.K., D.J.M.) and Molecular Biology (S.A.K.) and the Howard Hughes Medical Institute (D.J.M.), University of Texas Southwestern Medical Center, Dallas, Texas 75390; Departments of Internal Medicine and Pharmacology (J.L., R.J.A.) and the Michigan Metabolomics and Obesity Center (R.C.), University of Michigan, Ann Arbor, Michigan 48109; and the Institute of Metabolism and Systems Research (B.A.H., W.A.), University of Birmingham, Birmingham B15 2TT, United Kingdom
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Stiborová M, Bárta F, Levová K, Hodek P, Schmeiser HH, Arlt VM, Martínek V. A Mechanism of O-Demethylation of Aristolochic Acid I by Cytochromes P450 and Their Contributions to This Reaction in Human and Rat Livers: Experimental and Theoretical Approaches. Int J Mol Sci 2015; 16:27561-75. [PMID: 26593908 PMCID: PMC4661905 DOI: 10.3390/ijms161126047] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 10/14/2015] [Revised: 10/30/2015] [Accepted: 11/05/2015] [Indexed: 01/30/2023] Open
Abstract
Aristolochic acid I (AAI) is a plant alkaloid causing aristolochic acid nephropathy, Balkan endemic nephropathy and their associated urothelial malignancies. AAI is detoxified by cytochrome P450 (CYP)-mediated O-demethylation to 8-hydroxyaristolochic acid I (aristolochic acid Ia, AAIa). We previously investigated the efficiencies of human and rat CYPs in the presence of two other components of the mixed-functions-oxidase system, NADPH:CYP oxidoreductase and cytochrome b₅, to oxidize AAI. Human and rat CYP1A are the major enzymes oxidizing AAI. Other CYPs such as CYP2C, 3A4, 2D6, 2E1, and 1B1, also form AAIa, but with much lower efficiency than CYP1A. Based on velocities of AAIa formation by examined CYPs and their expression levels in human and rat livers, here we determined the contributions of individual CYPs to AAI oxidation in these organs. Human CYP1A2 followed by CYP2C9, 3A4 and 1A1 were the major enzymes contributing to AAI oxidation in human liver, while CYP2C and 1A were most important in rat liver. We employed flexible in silico docking methods to explain the differences in AAI oxidation in the liver by human CYP1A1, 1A2, 2C9, and 3A4, the enzymes that all O-demethylate AAI, but with different effectiveness. We found that the binding orientations of the methoxy group of AAI in binding centers of the CYP enzymes and the energies of AAI binding to the CYP active sites dictate the efficiency of AAI oxidation. Our results indicate that utilization of experimental and theoretical methods is an appropriate study design to examine the CYP-catalyzed reaction mechanisms of AAI oxidation and contributions of human hepatic CYPs to this metabolism.
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Affiliation(s)
- Marie Stiborová
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, Prague 2 CZ-12843, Czech Republic.
| | - František Bárta
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, Prague 2 CZ-12843, Czech Republic.
| | - Kateřina Levová
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, Prague 2 CZ-12843, Czech Republic.
| | - Petr Hodek
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, Prague 2 CZ-12843, Czech Republic.
| | - Heinz H Schmeiser
- Division of Radiopharmaceutical Chemistry, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg 69120, Germany.
| | - Volker M Arlt
- Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment and Health, King's College London, London SE1 9NH, UK.
| | - Václav Martínek
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, Prague 2 CZ-12843, Czech Republic.
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Burkhardt T, Letzel T, Drewes JE, Grassmann J. Comprehensive assessment of Cytochrome P450 reactions: A multiplex approach using real-time ESI-MS. Biochim Biophys Acta Gen Subj 2015; 1850:2573-81. [PMID: 26409144 DOI: 10.1016/j.bbagen.2015.09.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 05/21/2015] [Revised: 09/01/2015] [Accepted: 09/22/2015] [Indexed: 01/14/2023]
Abstract
BACKGROUND The detailed analysis of Cytochrome P450 (CYP) catalyzed reactions is of great interest, since those are of importance for biotechnical applications, drug interaction studies and environmental research. Often cocktail approaches are carried out in order to monitor several CYP activities in a single experiment. Commonly in these approaches product formation is detected and IC50 values are determined. METHODS In the present work, the reactions of two different CYP isoforms were monitored using real-time electrospray ionization mass spectrometry. Multiplex experiments using the highly specific CYP2A6 with its corresponding substrate coumarin as well as the highly promiscuous CYP3A4 with testosterone were conducted. Product formation and substrate depletion were simultaneously monitored and compared to the single CYP experiments. The diffusion-controlled rate of reaction and conversion rates that are used as parameters to assess the enzymatic activity were calculated for all measurements conducted. RESULTS Differences in conversion rates and the theoretical rate of reaction that were observed for single CYP and multiplex experiments, respectively, reveal the complexity of the underlying mechanisms. Findings of this study imply that there might be distinct deviations between product formation and substrate degradation when mixtures are used. CONCLUSIONS Detailed results indicate that for a comprehensive assessment of these enzymatic reactions both product and substrate should be considered. GENERAL SIGNIFICANCE The direct hyphenation of enzymatic reactions to mass spectrometry allows for a comprehensive assessment of enzymatic behavior. Due to the benefits of this technique, the entire system which includes substrate, product and intermediates can be investigated. Thus, besides IC50 values further information regarding the enzymatic behavior offers the opportunity for a more detailed insight.
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Affiliation(s)
- Therese Burkhardt
- Chair of Urban Water Systems Engineering, Technical University of Munich, Am Coulombwall, 85748 Garching, Germany.
| | - Thomas Letzel
- Chair of Urban Water Systems Engineering, Technical University of Munich, Am Coulombwall, 85748 Garching, Germany.
| | - Jörg E Drewes
- Chair of Urban Water Systems Engineering, Technical University of Munich, Am Coulombwall, 85748 Garching, Germany.
| | - Johanna Grassmann
- Chair of Urban Water Systems Engineering, Technical University of Munich, Am Coulombwall, 85748 Garching, Germany.
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23
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Gadel S, Friedel C, Kharasch ED. Differences in Methadone Metabolism by CYP2B6 Variants. Drug Metab Dispos 2015; 43:994-1001. [PMID: 25897175 PMCID: PMC4468442 DOI: 10.1124/dmd.115.064352] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 03/17/2015] [Accepted: 04/20/2015] [Indexed: 12/22/2022] Open
Abstract
Methadone is a long-acting opioid with considerable unexplained interindividual variability in clearance. Cytochrome P450 2B6 (CYP2B6) mediates clinical methadone clearance and metabolic inactivation via N-demethylation to 2-ethyl-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP). Retrospective studies suggest that individuals with the CYP2B6*6 allelic variant have higher methadone plasma concentrations. Catalytic activities of CYP2B6 variants are highly substrate- and expression-system dependent. This investigation evaluated methadone N-demethylation by expressed human CYP2B6 allelic variants in an insect cell coexpression system containing P450 reductase. Additionally, the influence of coexpressing cytochrome b5, whose role in metabolism can be inhibitory or stimulatory depending on the P450 isoform and substrate, on methadone metabolism, was evaluated. EDDP formation from therapeutic (0.25-1 μM) R- and S-methadone concentrations was CYP2B6.4 ≥ CYP2B6.1 ≥ CYP2B6.5 >> CYP2B6.9 ≈ CYP2B6.6, and undetectable from CYP2B6.18. Coexpression of b5 had small and variant-specific effects at therapeutic methadone concentrations but at higher concentrations stimulated EDDP formation by CYP2B6.1, CYP2B6.4, CYP2B6.5, and CYP2B6.9 but not CYP2B6.6. In vitro intrinsic clearances were generally CYP2B6.4 ≥ CYP2B6.1 > CYP2B6.5 > CYP2B6.9 ≥ CYP2B6.6. Stereoselective methadone metabolism (S>R) was maintained with all CYP2B6 variants. These results show that methadone N-demethylation by CYP2B6.4 is greater compared with CYP2B6.1, whereas CYP2B6.9 and CYP2B6.6 (which both contain the 516G>T, Q172H polymorphism), are catalytically deficient. The presence or absence of b5 in expression systems may explain previously reported disparate catalytic activities of CYP2B6 variants for specific substrates. Differences in methadone metabolism by CYP2B6 allelic variants provide a mechanistic understanding of pharmacogenetic variability in clinical methadone metabolism and clearance.
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Affiliation(s)
- Sarah Gadel
- Department of Anesthesiology, Division of Clinical and Translational Research (S.G., C.F., E.D.K.) and the Department of Biochemistry and Molecular Biophysics (E.D.K.), Washington University in St. Louis, St. Louis, Missouri
| | - Christina Friedel
- Department of Anesthesiology, Division of Clinical and Translational Research (S.G., C.F., E.D.K.) and the Department of Biochemistry and Molecular Biophysics (E.D.K.), Washington University in St. Louis, St. Louis, Missouri
| | - Evan D Kharasch
- Department of Anesthesiology, Division of Clinical and Translational Research (S.G., C.F., E.D.K.) and the Department of Biochemistry and Molecular Biophysics (E.D.K.), Washington University in St. Louis, St. Louis, Missouri
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24
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Zhang H, Gao N, Liu T, Fang Y, Qi B, Wen Q, Zhou J, Jia L, Qiao H. Effect of Cytochrome b5 Content on the Activity of Polymorphic CYP1A2, 2B6, and 2E1 in Human Liver Microsomes. PLoS One 2015; 10:e0128547. [PMID: 26046844 PMCID: PMC4457846 DOI: 10.1371/journal.pone.0128547] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 02/16/2015] [Accepted: 04/28/2015] [Indexed: 11/18/2022] Open
Abstract
Human cytochrome b5 (Cyt b5) plays important roles in cytochrome P450 (CYP)-mediated drug metabolism. However, the expression level of Cyt b5 in normal human liver remains largely unknown. The effect of Cyt b5 on overall CYP activity in human liver microsomes (HLM) has rarely been reported and the relationship between Cyt b5 and the activity of polymorphic CYP has not been systematically investigated. In this study, we found that the median value of Cyt b5 protein was 270.01 pmol/mg from 123 HLM samples, and 12- and 19-fold individual variation was observed in Cyt b5 mRNA and protein levels, respectively. Gender and smoking clearly influenced Cyt b5 content. In addition, we found that Cyt b5 protein levels significantly correlated with the overall activity of CYP1A2, 2B6, and 2E1 in HLM. However, when the CYP activities were sorted by single nucleotide polymorphisms (SNP), the effect of Cyt b5 protein on the kinetic parameters varied greatly. There were significant correlations between Cyt b5 content and Vmax and CLint of CYP1A2 wild-types (3860GG, 2159GG, and 5347CC) as well as homozygous mutants (163AA and 3113GG). In contrast to Vmax and CLint, the Km of CYP2B6 516GG and 785AA genotypes was inversely associated with Cyt b5 content. Correlations between Cyt b5 content and Vmax and CLint of CYP2E1 -1293GG, -1293GC, 7632TT, 7632TA, -333TT, and -352AA genotypes were also observed. In conclusion, Cyt b5 expression levels varied considerably in the Chinese cohort from this study. Cyt b5 had significant impact on the overall activity of CYP1A2, 2B6, and 2E1 in HLM and the effects of Cyt b5 protein on polymorphic CYP1A2, 2B6, and 2E1 activity were SNP-dependent. These findings suggest that Cyt b5 plays an important role in CYP-mediated activities in HLM and may possibly be a contributing factor for the individual variation observed in CYP enzyme activities.
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Affiliation(s)
- Haifeng Zhang
- Institute of Clinical Pharmacology, Zhengzhou University, Zhengzhou, China
| | - Na Gao
- Institute of Clinical Pharmacology, Zhengzhou University, Zhengzhou, China
| | - Tingting Liu
- Institute of Clinical Pharmacology, Zhengzhou University, Zhengzhou, China
| | - Yan Fang
- Institute of Clinical Pharmacology, Zhengzhou University, Zhengzhou, China
| | - Bing Qi
- Institute of Clinical Pharmacology, Zhengzhou University, Zhengzhou, China
| | - Qiang Wen
- Institute of Clinical Pharmacology, Zhengzhou University, Zhengzhou, China
| | - Jun Zhou
- Institute of Clinical Pharmacology, Zhengzhou University, Zhengzhou, China
| | - Linjing Jia
- Institute of Clinical Pharmacology, Zhengzhou University, Zhengzhou, China
| | - Hailing Qiao
- Institute of Clinical Pharmacology, Zhengzhou University, Zhengzhou, China
- * E-mail:
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25
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Henderson CJ, McLaughlin LA, Scheer N, Stanley LA, Wolf CR. Cytochrome b5 is a major determinant of human cytochrome P450 CYP2D6 and CYP3A4 activity in vivo. Mol Pharmacol 2015; 87:733-9. [PMID: 25657337 DOI: 10.1124/mol.114.097394] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Indexed: 01/11/2023] Open
Abstract
The cytochrome P450-dependent mono-oxygenase system is responsible for the metabolism and disposition of chemopreventive agents, chemical toxins and carcinogens, and >80% of therapeutic drugs. Cytochrome P450 (P450) activity is regulated transcriptionally and by the rate of electron transfer from P450 reductase. In vitro studies have demonstrated that cytochrome b5 (Cyb5) also modulates P450 function. We recently showed that hepatic deletion of Cyb5 in the mouse (HBN) markedly alters in vivo drug pharmacokinetics; a key outstanding question is whether Cyb5 modulates the activity of the major human P450s in drug disposition in vivo. To address this, we crossed mice humanized for CYP2D6 or CYP3A4 with mice carrying a hepatic Cyb5 deletion. In vitro triazolam 4-hydroxylation (probe reaction for CYP3A4) was reduced by >50% in hepatic microsomes from CYP3A4-HBN mice compared with controls. Similar reductions in debrisoquine 4-hydroxylation and metoprolol α-hydroxylation were observed using CYP2D6-HBN microsomes, indicating a significant role for Cyb5 in the activity of both enzymes. This effect was confirmed by the concentration-dependent restoration of CYP3A4-mediated triazolam turnover and CYP2D6-mediated bufuralol and debrisoquine turnover on addition of Escherichia coli membranes containing recombinant Cyb5. In vivo, the peak plasma concentration and area under the concentration time curve from 0 to 8 hours (AUC0-8 h) of triazolam were increased 4- and 5.7-fold, respectively, in CYP3A4-HBN mice. Similarly, the pharmacokinetics of bufuralol and debrisoquine were significantly altered in CYP2D6-HBN mice, the AUC0-8 h being increased ∼1.5-fold and clearance decreased by 40-60%. These data demonstrate that Cyb5 can be a major determinant of CYP3A4 and CYP2D6 activity in vivo, with a potential impact on the metabolism, efficacy, and side effects of numerous therapeutic drugs.
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Affiliation(s)
- Colin J Henderson
- Medical Research Institute, University of Dundee, Ninewells Hospital and Medical School, University of Dundee, Dundee, United Kingdom (C.J.H., L.A.M., C.R.W.), TaconicArtemis, Cologne, Germany (N.S.); and Consultant in Investigative Toxicology, Linlithgow, United Kingdom (L.A.S.)
| | - Lesley A McLaughlin
- Medical Research Institute, University of Dundee, Ninewells Hospital and Medical School, University of Dundee, Dundee, United Kingdom (C.J.H., L.A.M., C.R.W.), TaconicArtemis, Cologne, Germany (N.S.); and Consultant in Investigative Toxicology, Linlithgow, United Kingdom (L.A.S.)
| | - Nico Scheer
- Medical Research Institute, University of Dundee, Ninewells Hospital and Medical School, University of Dundee, Dundee, United Kingdom (C.J.H., L.A.M., C.R.W.), TaconicArtemis, Cologne, Germany (N.S.); and Consultant in Investigative Toxicology, Linlithgow, United Kingdom (L.A.S.)
| | - Lesley A Stanley
- Medical Research Institute, University of Dundee, Ninewells Hospital and Medical School, University of Dundee, Dundee, United Kingdom (C.J.H., L.A.M., C.R.W.), TaconicArtemis, Cologne, Germany (N.S.); and Consultant in Investigative Toxicology, Linlithgow, United Kingdom (L.A.S.)
| | - C Roland Wolf
- Medical Research Institute, University of Dundee, Ninewells Hospital and Medical School, University of Dundee, Dundee, United Kingdom (C.J.H., L.A.M., C.R.W.), TaconicArtemis, Cologne, Germany (N.S.); and Consultant in Investigative Toxicology, Linlithgow, United Kingdom (L.A.S.)
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26
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Zhang M, Huang R, Im SC, Waskell L, Ramamoorthy A. Effects of membrane mimetics on cytochrome P450-cytochrome b5 interactions characterized by NMR spectroscopy. J Biol Chem 2015; 290:12705-18. [PMID: 25795780 DOI: 10.1074/jbc.m114.597096] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 07/17/2014] [Indexed: 01/08/2023] Open
Abstract
Mammalian cytochrome P450 (P450) is a membrane-bound monooxygenase whose catalytic activities require two electrons to be sequentially delivered from its redox partners: cytochrome b5 (cytb5) and cytochrome P450 reductase, both of which are membrane proteins. Although P450 functional activities are known to be affected by lipids, experimental evidence to reveal the effect of membrane on P450-cytb5 interactions is still lacking. Here, we present evidence for the influence of phospholipid bilayers on complex formation between rabbit P450 2B4 (CYP2B4) and rabbit cytb5 at the atomic level, utilizing NMR techniques. General line broadening and modest chemical shift perturbations of cytb5 resonances characterize CYP2B4-cytb5 interactions on the intermediate time scale. More significant intensity attenuation and a more specific protein-protein binding interface are observed in bicelles as compared with lipid-free solution, highlighting the importance of the lipid bilayer in stabilizing stronger and more specific interactions between CYP2B4 and cytb5, which may lead to a more efficient electron transfer. Similar results observed for the interactions between CYP2B4 lacking the transmembrane domain (tr-CYP2B4) and cytb5 imply interactions between tr-CYP2B4 and the membrane surface, which might assist in CYP2B4-cytb5 complex formation by orienting tr-CYP2B4 for efficient contact with cytb5. Furthermore, the observation of weak and nonspecific interactions between CYP2B4 and cytb5 in micelles suggests that lipid bilayer structures and low curvature membrane surface are preferable for CYP2B4-cytb5 complex formation. Results presented in this study provide structural insights into the mechanism behind the important role that the lipid bilayer plays in the interactions between P450s and their redox partners.
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Affiliation(s)
- Meng Zhang
- From the Department of Chemistry and Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055 and
| | - Rui Huang
- From the Department of Chemistry and Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055 and
| | - Sang-Choul Im
- the Department of Anesthesiology, University of Michigan and Veterans Affairs Medical Center, Ann Arbor, Michigan 48105
| | - Lucy Waskell
- the Department of Anesthesiology, University of Michigan and Veterans Affairs Medical Center, Ann Arbor, Michigan 48105
| | - Ayyalusamy Ramamoorthy
- From the Department of Chemistry and Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055 and
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27
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Insights into the role of substrates on the interaction between cytochrome b5 and cytochrome P450 2B4 by NMR. Sci Rep 2015; 5:8392. [PMID: 25687717 PMCID: PMC4330534 DOI: 10.1038/srep08392] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 11/28/2014] [Accepted: 12/16/2014] [Indexed: 01/08/2023] Open
Abstract
Mammalian cytochrome b5 (cyt b5) is a membrane-bound protein capable of donating an electron to cytochrome P450 (P450) in the P450 catalytic cycle. The interaction between cyt b5 and P450 has been reported to be affected by the substrates of P450; however, the mechanism of substrate modulation on the cyt b5-P450 complex formation is still unknown. In this study, the complexes between full-length rabbit cyt b5 and full-length substrate-free/substrate-bound cytochrome P450 2B4 (CYP2B4) are investigated using NMR techniques. Our findings reveal that the population of complexes is ionic strength dependent, implying the importance of electrostatic interactions in the complex formation process. The observation that the cyt b5-substrate-bound CYP2B4 complex shows a weaker dependence on ionic strength than the cyt b5-substrate-free CYP2B4 complex suggests the presence of a larger fraction of steoreospecific complexes when CYP2B4 is substrate-bound. These results suggest that a CYP2B4 substrate likely promotes specific interactions between cyt b5 and CYP2B4. Residues D65, V66, T70, D71 and A72 are found to be involved in specific interactions between the two proteins due to their weak response to ionic strength change. These findings provide insights into the mechanism underlying substrate modulation on the cyt b5-P450 complexation process.
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28
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Henderson CJ, McLaughlin LA, Osuna-Cabello M, Taylor M, Gilbert I, McLaren AW, Wolf CR. Application of a novel regulatable Cre recombinase system to define the role of liver and gut metabolism in drug oral bioavailability. Biochem J 2015; 465:479-88. [PMID: 25377919 PMCID: PMC6949133 DOI: 10.1042/bj20140582] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Academic Contribution Register] [Indexed: 02/02/2023]
Abstract
The relative contribution of hepatic compared with intestinal oxidative metabolism is a crucial factor in drug oral bioavailability and therapeutic efficacy. Oxidative metabolism is mediated by the cytochrome P450 mono-oxygenase system to which cytochrome P450 reductase (POR) is the essential electron donor. In order to study the relative importance of these pathways in drug disposition, we have generated a novel mouse line where Cre recombinase is driven off the endogenous Cyp1a1 gene promoter; this line was then crossed on to a floxed POR mouse. A 40 mg/kg dose of the Cyp1a1 inducer 3-methylcholanthrene (3MC) eliminated POR expression in both liver and small intestine, whereas treatment at 4 mg/kg led to a more targeted deletion in the liver. Using this approach, we have studied the pharmacokinetics of three probe drugs--paroxetine, midazolam, nelfinavir--and show that intestinal metabolism is a determinant of oral bioavailability for the two latter compounds. The Endogenous Reductase Locus (ERL) mouse represents a significant advance on previous POR deletion models as it allows direct comparison of hepatic and intestinal effects on drug and xenobiotic clearance using lower doses of a single Cre inducing agent, and in addition minimizes any cytotoxic effects, which may compromise interpretation of the experimental data.
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Affiliation(s)
- Colin J. Henderson
- Division of Cancer Research, Level 9, Jacqui Wood Cancer Centre, University of Dundee, Ninewells Hospital & Medical School, Dundee DD1 9SY, U.K
| | - Lesley A. McLaughlin
- Division of Cancer Research, Level 9, Jacqui Wood Cancer Centre, University of Dundee, Ninewells Hospital & Medical School, Dundee DD1 9SY, U.K
| | - Maria Osuna-Cabello
- Drug Discovery Unit, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, U.K
| | - Malcolm Taylor
- Drug Discovery Unit, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, U.K
| | - Ian Gilbert
- Drug Discovery Unit, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, U.K
| | - Aileen W. McLaren
- Division of Cancer Research, Level 9, Jacqui Wood Cancer Centre, University of Dundee, Ninewells Hospital & Medical School, Dundee DD1 9SY, U.K
| | - C. Roland Wolf
- Drug Discovery Unit, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, U.K
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29
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MacLeod AK, Fallon PG, Sharp S, Henderson CJ, Wolf CR, Huang JTJ. An enhanced in vivo stable isotope labeling by amino acids in cell culture (SILAC) model for quantification of drug metabolism enzymes. Mol Cell Proteomics 2015; 14:750-60. [PMID: 25561501 PMCID: PMC4349992 DOI: 10.1074/mcp.m114.043661] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Academic Contribution Register] [Indexed: 11/06/2022] Open
Abstract
Many of the enzymes involved in xenobiotic metabolism are maintained at a low basal level and are only synthesized in response to activation of upstream sensor/effector proteins. This induction can have implications in a variety of contexts, particularly during the study of the pharmacokinetics, pharmacodynamics, and drug–drug interaction profile of a candidate therapeutic compound. Previously, we combined in vivo SILAC material with a targeted high resolution single ion monitoring (tHR/SIM) LC-MS/MS approach for quantification of 197 peptide pairs, representing 51 drug metabolism enzymes (DME), in mouse liver. However, as important enzymes (for example, cytochromes P450 (Cyp) of the 1a and 2b subfamilies) are maintained at low or undetectable levels in the liver of unstimulated metabolically labeled mice, quantification of these proteins was unreliable. In the present study, we induced DME expression in labeled mice through synchronous ligand-mediated activation of multiple upstream nuclear receptors, thereby enhancing signals for proteins including Cyps 1a, 2a, 2b, 2c, and 3a. With this enhancement, 115 unique, lysine-containing, Cyp-derived peptides were detected in the liver of a single animal, as opposed to 56 in a pooled sample from three uninduced animals. A total of 386 peptide pairs were quantified by tHR/SIM, representing 68 Phase I, 30 Phase II, and eight control proteins. This method was employed to quantify changes in DME expression in the hepatic cytochrome P450 reductase null (HRN) mouse. We observed compensatory induction of several enzymes, including Cyps 2b10, 2c29, 2c37, 2c54, 2c55, 2e1, 3a11, and 3a13, carboxylesterase (Ces) 2a, and glutathione S-transferases (Gst) m2 and m3, along with down-regulation of hydroxysteroid dehydrogenases (Hsd) 11b1 and 17b6. Using DME-enhanced in vivo SILAC material with tHR/SIM, therefore, permits the robust analysis of multiple DME of importance to xenobiotic metabolism, with improved utility for the study of drug pharmacokinetics, pharmacodynamics, and of chemically treated and genetically modified mouse models.
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Affiliation(s)
- A Kenneth MacLeod
- From the ‡Jacqui Wood Cancer Centre, Medical Research Institute, Ninewells Hospital and Medical School, University of Dundee, Dundee DD1 9SY, Scotland
| | - Padraic G Fallon
- §School of Medicine, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
| | - Sheila Sharp
- From the ‡Jacqui Wood Cancer Centre, Medical Research Institute, Ninewells Hospital and Medical School, University of Dundee, Dundee DD1 9SY, Scotland
| | - Colin J Henderson
- From the ‡Jacqui Wood Cancer Centre, Medical Research Institute, Ninewells Hospital and Medical School, University of Dundee, Dundee DD1 9SY, Scotland
| | - C Roland Wolf
- From the ‡Jacqui Wood Cancer Centre, Medical Research Institute, Ninewells Hospital and Medical School, University of Dundee, Dundee DD1 9SY, Scotland
| | - Jeffrey T-J Huang
- From the ‡Jacqui Wood Cancer Centre, Medical Research Institute, Ninewells Hospital and Medical School, University of Dundee, Dundee DD1 9SY, Scotland;
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30
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Arlt VM, Henderson CJ, Wolf CR, Stiborová M, Phillips DH. The Hepatic Reductase Null (HRN™) and Reductase Conditional Null (RCN) mouse models as suitable tools to study metabolism, toxicity and carcinogenicity of environmental pollutants. Toxicol Res (Camb) 2015. [DOI: 10.1039/c4tx00116h] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Indexed: 01/03/2023] Open
Abstract
This review describes the applicability of the Hepatic Reductase Null (HRN) and Reductase Conditional Null (RCN) mouse models to study carcinogen metabolism.
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Affiliation(s)
- Volker M. Arlt
- Analytical and Environmental Sciences Division
- MRC-PHE Centre for Environment and Health
- King's College London
- London SE1 9NH
- UK
| | - Colin J. Henderson
- Division of Cancer Research
- Medical Research Institute
- Jacqui Wood Cancer Centre
- University of Dundee
- Dundee DD1 9SY
| | - C. Roland Wolf
- Division of Cancer Research
- Medical Research Institute
- Jacqui Wood Cancer Centre
- University of Dundee
- Dundee DD1 9SY
| | - Marie Stiborová
- Department of Biochemistry
- Faculty of Science
- Charles University
- 128 40 Prague 2
- Czech Republic
| | - David H. Phillips
- Analytical and Environmental Sciences Division
- MRC-PHE Centre for Environment and Health
- King's College London
- London SE1 9NH
- UK
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31
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Stiborová M, Černá V, Moserová M, Mrízová I, Arlt VM, Frei E. The anticancer drug ellipticine activated with cytochrome P450 mediates DNA damage determining its pharmacological efficiencies: studies with rats, Hepatic Cytochrome P450 Reductase Null (HRN™) mice and pure enzymes. Int J Mol Sci 2014; 16:284-306. [PMID: 25547492 PMCID: PMC4307247 DOI: 10.3390/ijms16010284] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 10/19/2014] [Accepted: 12/17/2014] [Indexed: 12/30/2022] Open
Abstract
Ellipticine is a DNA-damaging agent acting as a prodrug whose pharmacological efficiencies and genotoxic side effects are dictated by activation with cytochrome P450 (CYP). Over the last decade we have gained extensive experience in using pure enzymes and various animal models that helped to identify CYPs metabolizing ellipticine. In this review we focus on comparison between the in vitro and in vivo studies and show a necessity of both approaches to obtain valid information on CYP enzymes contributing to ellipticine metabolism. Discrepancies were found between the CYP enzymes activating ellipticine to 13-hydroxy- and 12-hydroxyellipticine generating covalent DNA adducts and those detoxifying this drug to 9-hydroxy- and 7-hydroellipticine in vitro and in vivo. In vivo, formation of ellipticine-DNA adducts is dependent not only on expression levels of CYP3A, catalyzing ellipticine activation in vitro, but also on those of CYP1A that oxidize ellipticine in vitro mainly to the detoxification products. The finding showing that cytochrome b5 alters the ratio of ellipticine metabolites generated by CYP1A1/2 and 3A4 explained this paradox. Whereas the detoxification of ellipticine by CYP1A and 3A is either decreased or not changed by cytochrome b5, activation leading to ellipticine-DNA adducts increased considerably. We show that (I) the pharmacological effects of ellipticine mediated by covalent ellipticine-derived DNA adducts are dictated by expression levels of CYP1A, 3A and cytochrome b5, and its own potency to induce these enzymes in tumor tissues, (II) animal models, where levels of CYPs are either knocked out or induced are appropriate to identify CYPs metabolizing ellipticine in vivo, and (III) extrapolation from in vitro data to the situation in vivo is not always possible, confirming the need for these animal models.
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Affiliation(s)
- Marie Stiborová
- Department of Biochemistry, Faculty of Science, Charles University, Hlavova 2030, CZ-12843 Prague 2, Czech Republic.
| | - Věra Černá
- Department of Biochemistry, Faculty of Science, Charles University, Hlavova 2030, CZ-12843 Prague 2, Czech Republic.
| | - Michaela Moserová
- Department of Biochemistry, Faculty of Science, Charles University, Hlavova 2030, CZ-12843 Prague 2, Czech Republic.
| | - Iveta Mrízová
- Department of Biochemistry, Faculty of Science, Charles University, Hlavova 2030, CZ-12843 Prague 2, Czech Republic.
| | - Volker M Arlt
- Analytical and Environmental Sciences Division, MRC-PHE Centre for Environmental & Health, King's College London, 150 Stamford Street, London SE1 9NH, UK.
| | - Eva Frei
- Division of Preventive Oncology, National Center for Tumor Diseases, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.
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32
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Regulation of cytochrome b5 expression by miR-223 in human liver: effects on cytochrome P450 activities. Pharm Res 2014; 31:780-94. [PMID: 24078287 DOI: 10.1007/s11095-013-1200-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 05/11/2013] [Accepted: 08/31/2013] [Indexed: 01/24/2023]
Abstract
PURPOSE Cytochrome b5 (b5) is a hemoprotein that transfers electrons to several enzymes to fulfill functions in fatty acid desaturation, methemoglobin reduction, steroidogenesis, and drug metabolism. Despite the importance of b5, the regulation of b5 expression in human liver remains largely unknown. We investigated whether microRNA (miRNA) might be involved in the regulation of human b5. METHODS Twenty-four human liver specimens were used for correlation analysis. In silico analysis and luciferase assay were performed to determine whether the predicted miRNAs functionally target to b5. The miR-223 was overexpressed into HepG2 cells infected with adenovirus expressing human cytochrome P450. RESULTS In human livers, the b5 protein levels were not positively correlated with the b5 mRNA levels, and miR-223 levels were inversely correlated with the b5 mRNA levels or the translational efficiencies. The luciferase assay showed that miR-223 functionally binds to the element in the 3′-untranslated region of b5 mRNA. The overexpression of miR-223 significantly reduced the endogenous b5 protein level and the mRNA stability in HepG2 cells. Moreover, the overexpression of miR-223 significantly reduced CYP3A4-catalyzed testosterone 6β-hydroxylation activity and CYP2E1-catalyzed chlorzoxazone 6-hydroxylase activity but not CYP1A2-catalyzed 7-ethoxyresorufin O-deethylase activity. CONCLUSIONS miR-223 down-regulates b5 expression in the human liver, modulating P450 activities.
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33
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Jeřábek P, Florián J, Stiborová M, Martínek V. Flexible docking-based molecular dynamics/steered molecular dynamics calculations of protein-protein contacts in a complex of cytochrome P450 1A2 with cytochrome b5. Biochemistry 2014; 53:6695-705. [PMID: 25313797 DOI: 10.1021/bi500814t] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Indexed: 11/30/2022]
Abstract
Formation of transient complexes of cytochrome P450 (P450) with another protein of the endoplasmic reticulum membrane, cytochrome b5 (cyt b5), dictates the catalytic activities of several P450s. Therefore, we examined formation and binding modes of the complex of human P450 1A2 with cyt b5. Docking of soluble domains of these proteins was performed using an information-driven flexible docking approach implemented in HADDOCK. Stabilities of the five unique binding modes of the P450 1A2-cyt b5 complex yielded by HADDOCK were evaluated using explicit 10 ns molecular dynamics (MD) simulations in aqueous solution. Further, steered MD was used to compare the stability of the individual P450 1A2-cyt b5 binding modes. The best binding mode was characterized by a T-shaped mutual orientation of the porphyrin rings and a 10.7 Å distance between the two redox centers, thus satisfying the condition for a fast electron transfer. Mutagenesis studies and chemical cross-linking, which, in the absence of crystal structures, were previously used to deduce specific P450-cyt b5 interactions, indicated that the negatively charged convex surface of cyt b5 binds to the positively charged concave surface of P450. Our simulations further elaborate structural details of this interface, including nine ion pairs between R95, R100, R138, R362, K442, K455, and K465 side chains of P450 1A2 and E42, E43, E49, D65, D71, and heme propionates of cyt b5. The universal heme-centric system of internal coordinates was proposed to facilitate consistent classification of the orientation of the two porphyrins in any protein complex.
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Affiliation(s)
- Petr Jeřábek
- Department of Biochemistry, Faculty of Science, Charles University in Prague , Albertov 2030, 128 43 Prague 2, Czech Republic
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Kandel SE, Lampe JN. Role of protein-protein interactions in cytochrome P450-mediated drug metabolism and toxicity. Chem Res Toxicol 2014; 27:1474-86. [PMID: 25133307 PMCID: PMC4164225 DOI: 10.1021/tx500203s] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Academic Contribution Register] [Indexed: 01/29/2023]
Abstract
![]()
Through their unique oxidative chemistry,
cytochrome P450 monooxygenases
(CYPs) catalyze the elimination of most drugs and toxins from the
human body. Protein–protein interactions play a critical role
in this process. Historically, the study of CYP–protein interactions
has focused on their electron transfer partners and allosteric mediators,
cytochrome P450 reductase and cytochrome b5. However, CYPs can bind
other proteins that also affect CYP function. Some examples include
the progesterone receptor membrane component 1, damage resistance
protein 1, human and bovine serum albumin, and intestinal fatty acid
binding protein, in addition to other CYP isoforms. Furthermore, disruption
of these interactions can lead to altered paths of metabolism and
the production of toxic metabolites. In this review, we summarize
the available evidence for CYP protein–protein interactions
from the literature and offer a discussion of the potential impact
of future studies aimed at characterizing noncanonical protein–protein
interactions with CYP enzymes.
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Affiliation(s)
- Sylvie E Kandel
- XenoTech, LLC , 16825 West 116th Street, Lenexa, Kansas 66219, United States
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Zhang YW, Bao MH, Hu L, Qu Q, Zhou HH. Dose-response of oridonin on hepatic cytochromes P450 mRNA expression and activities in mice. JOURNAL OF ETHNOPHARMACOLOGY 2014; 155:714-720. [PMID: 24933226 DOI: 10.1016/j.jep.2014.06.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Academic Contribution Register] [Received: 03/08/2014] [Revised: 05/24/2014] [Accepted: 06/04/2014] [Indexed: 06/03/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Oridonin, the major terpene found in Rabdosia rubescens, is widely used as a dietary supplement or therapeutic drug. The effects of oridonin on drug processing genes, such as cytochrome P450 and nuclear receptors, were still unclear. Therefore, the present study investigated the influence of oridonin on the hepatic drug metabolizing system to evaluate the safety through its drug interaction potential. MATERIALS AND METHODS In this study, eight-week-old male C57BL/6 mice were treated oridonin orally (0, 25, 50, 100, 200 mg/kg, i.g.) for 15 days. The effects of oridonin on major Cyps in mice livers were examined at both the mRNA and enzyme activity levels. RESULTS In general, there are no significant influence of various dose of oridonin on mice liver function. However, oridonin significantly increased Cyps (1a, 2a, 2d, 2e, 2c and 3a family) mRNA expression. In addition, it could induce Cyps activity in microsome incubation at maximum dosage. To our knowledge, it is the first time to identify oridonin as a Cyps inducer in vivo. It also promotes the expression of CAR, PXR and POR. CONCLUSION These results indicate that, if studies in mice extrapolate to humans by orthologous genes, oridonin appears to be a risk to herb-drug interactions due to its induction effects on drug processing genes expression and activation.
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Affiliation(s)
- Yi-wen Zhang
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha 410008, China; Institute of Clinical Pharmacology, Xiangya School of Medicine, Central South University, 110 Xiangya Road, Changsha, Hunan 410078, China
| | - Mei-hua Bao
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha 410008, China; Institute of Clinical Pharmacology, Xiangya School of Medicine, Central South University, 110 Xiangya Road, Changsha, Hunan 410078, China; Department of Pharmacy, Changsha Medical University, Changsha 410219, China
| | - Lei Hu
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha 410008, China; Institute of Clinical Pharmacology, Xiangya School of Medicine, Central South University, 110 Xiangya Road, Changsha, Hunan 410078, China
| | - Qiang Qu
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha 410008, China; Institute of Clinical Pharmacology, Xiangya School of Medicine, Central South University, 110 Xiangya Road, Changsha, Hunan 410078, China
| | - Hong-hao Zhou
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha 410008, China; Institute of Clinical Pharmacology, Xiangya School of Medicine, Central South University, 110 Xiangya Road, Changsha, Hunan 410078, China.
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Samhan-Arias AK, Gutierrez-Merino C. Purified NADH-cytochrome b5 reductase is a novel superoxide anion source inhibited by apocynin: sensitivity to nitric oxide and peroxynitrite. Free Radic Biol Med 2014; 73:174-89. [PMID: 22922784 DOI: 10.1016/j.freeradbiomed.2014.04.033] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Academic Contribution Register] [Received: 02/04/2014] [Revised: 04/15/2014] [Accepted: 04/29/2014] [Indexed: 12/14/2022]
Abstract
Cytochrome b5 reductase (Cb5R) is a pleiotropic flavoprotein that catalyzes multiple one-electron reduction reactions with various redox partners in cells. In earlier work from our laboratory, we have shown its implication in the generation of reactive oxygen species (ROS), primarily a superoxide anion overshoot peak, which plays a major role as a triggering event for the acceleration of apoptosis in cerebellar granule neurons in culture. However, the results obtained in that work did not allow us to exclude the possibility that this superoxide anion production could be derived from Cb5R acting in concert with other cellular components. In this work, we have purified Cb5R from pig liver and we have experimentally shown that this enzyme catalyzed NADH-dependent production of superoxide anion, assayed with cytochrome c and nitroblue tetrazolium as detection reagents for this particular ROS. The basic kinetic parameters for this novel NADH-dependent activity of Cb5R at 37°C are Vmax = 3.0 ± 0.5 μmol/min/mg of purified Cb5R and KM(NADH) = 2.8 ± 0.3 μM NADH. In addition, we report that apocynin, a widely used inhibitor of nonmitochondrial ROS production in mammalian cell cultures and tissues, is a potent inhibitor of purified Cb5R activity at the concentrations used in the experiments done with cell cultures. In the presence of apocynin the KM(NADH) value of Cb5R increases, and docking simulations indicate that apocynin can bind to a site near to or partially overlapping the NADH binding site of Cb5R. Other ROS, such as nitric oxide and peroxynitrite, have inhibitory effects on purified Cb5R, providing the basis for a feedback cellular protection mechanism through modulation of excessive extramitochondrial superoxide anion production by Cb5R. Both kinetic assays and docking simulations suggest that nitric oxide-induced nitrosylation (including covalent adduction of nitroso functional groups) of Cb5R cysteines and peroxynitrite-induced tyrosine nitration and cysteine oxidation modified the conformation of the NADH binding domain leading to a decreased affinity of Cb5R for NADH.
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Affiliation(s)
- Alejandro K Samhan-Arias
- Department of Biochemistry and Molecular Biology, Faculty of Sciences, University of Extremadura, 06006 Badajoz, Spain.
| | - Carlos Gutierrez-Merino
- Department of Biochemistry and Molecular Biology, Faculty of Sciences, University of Extremadura, 06006 Badajoz, Spain
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Burke RS, Somasuntharam I, Rearden P, Brown D, Deshmukh SV, DiPietro MA, DiMuzio J, Eisenhandler R, Fauty SE, Gibson C, Gindy ME, Hamilton KA, Knemeyer I, Koeplinger KA, Kwon HW, Lifsted TQ, Menzel K, Patel M, Pudvah N, Rudd DJ, Seitzer J, Strapps WR, Prueksaritanont T, Thompson CD, Hochman JH, Carr BA. siRNA-Mediated Knockdown of P450 Oxidoreductase in Rats: A Tool to Reduce Metabolism by CYPs and Increase Exposure of High Clearance Compounds. Pharm Res 2014; 31:3445-60. [DOI: 10.1007/s11095-014-1433-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 02/13/2014] [Accepted: 06/03/2014] [Indexed: 11/28/2022]
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Scheer N, McLaughlin LA, Rode A, Macleod AK, Henderson CJ, Wolf CR. Deletion of 30 murine cytochrome p450 genes results in viable mice with compromised drug metabolism. Drug Metab Dispos 2014; 42:1022-30. [PMID: 24671958 DOI: 10.1124/dmd.114.057885] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Indexed: 11/22/2022] Open
Abstract
In humans, 75% of all drugs are metabolized by the cytochrome P450-dependent monooxygenase system. Enzymes encoded by the CYP2C, CYP2D, and CYP3A gene clusters account for ∼80% of this activity. There are profound species differences in the multiplicity of cytochrome P450 enzymes, and the use of mouse models to predict pathways of drug metabolism is further complicated by overlapping substrate specificity between enzymes from different gene families. To establish the role of the hepatic and extrahepatic P450 system in drug and foreign chemical disposition, drug efficacy, and toxicity, we created a unique mouse model in which 30 cytochrome P450 genes from the Cyp2c, Cyp2d, and Cyp3a gene clusters have been deleted. Remarkably, despite a wide range of putative important endogenous functions, Cyp2c/2d/3a KO mice were viable and fertile, demonstrating that these genes have evolved primarily as detoxification enzymes. Although there was no overt phenotype, detailed examination showed Cyp2c/2d/3a KO mice had a smaller body size (15%) and larger livers (20%). Changes in hepatic morphology and a decreased blood glucose (30%) were also noted. A five-drug cocktail of cytochrome P450 isozyme probe substrates were used to evaluate changes in drug pharmacokinetics; marked changes were observed in either the pharmacokinetics or metabolites formed from Cyp2c, Cyp2d, and Cyp3a substrates, whereas the metabolism of the Cyp1a substrate caffeine was unchanged. Thus, Cyp2c/2d/3a KO mice provide a powerful model to study the in vivo role of the P450 system in drug metabolism and efficacy, as well as in chemical toxicity.
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Affiliation(s)
- Nico Scheer
- TaconicArtemis, Köln, Germany (N.S., A.R.); and Medical Research Institute, University of Dundee, Ninewells Hospital and Medical School, University of Dundee, Dundee, United Kingdom (L.A.M., A.K.M., C.J.H., C.R.W.)
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Stiborová M, Moserová M, Černá V, Indra R, Dračínský M, Šulc M, Henderson CJ, Wolf CR, Schmeiser HH, Phillips DH, Frei E, Arlt VM. Cytochrome b5 and epoxide hydrolase contribute to benzo[a]pyrene-DNA adduct formation catalyzed by cytochrome P450 1A1 under low NADPH:P450 oxidoreductase conditions. Toxicology 2014; 318:1-12. [PMID: 24530354 DOI: 10.1016/j.tox.2014.02.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 12/05/2013] [Revised: 01/31/2014] [Accepted: 02/04/2014] [Indexed: 10/25/2022]
Abstract
In previous studies we had administered benzo[a]pyrene (BaP) to genetically engineered mice (HRN) which do not express NADPH:cytochrome P450 oxidoreductase (POR) in hepatocytes and observed higher DNA adduct levels in livers of these mice than in wild-type mice. To elucidate the reason for this unexpected finding we have used two different settings for in vitro incubations; hepatic microsomes from control and BaP-pretreated HRN mice and reconstituted systems with cytochrome P450 1A1 (CYP1A1), POR, cytochrome b5, and epoxide hydrolase (mEH) in different ratios. In microsomes from BaP-pretreated mice, in which Cyp1a1 was induced, higher levels of BaP metabolites were formed, mainly of BaP-7,8-dihydrodiol. At a low POR:CYP1A1 ratio of 0.05:1 in the reconstituted system, the amounts of BaP diones and BaP-9-ol formed were essentially the same as at an equimolar ratio, but formation of BaP-3-ol was ∼ 1.6-fold higher. Only after addition of mEH were BaP dihydrodiols found. Two BaP-DNA adducts were formed in the presence of mEH, but only one when CYP1A1 and POR were present alone. At a ratio of POR:CYP1A1 of 0.05:1, addition of cytochrome b5 increased CYP1A1-mediated BaP oxidation to most of its metabolites indicating that cytochrome b5 participates in the electron transfer from NADPH to CYP1A1 required for enzyme activity of this CYP. BaP-9-ol was formed even by CYP1A1 reconstituted with cytochrome b5 without POR. Our results suggest that in livers of HRN mice Cyp1a1, cytochrome b5 and mEH can effectively activate BaP to DNA binding species, even in the presence of very low amounts of POR.
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Affiliation(s)
- Marie Stiborová
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 Prague 2, Czech Republic.
| | - Michaela Moserová
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 Prague 2, Czech Republic
| | - Věra Černá
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 Prague 2, Czech Republic
| | - Radek Indra
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 Prague 2, Czech Republic
| | - Martin Dračínský
- Institute of Organic Chemistry and Biochemistry, v.v.i. Academy of Sciences, Flemingovo n. 2, 166 10 Prague 6, Czech Republic
| | - Miroslav Šulc
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 Prague 2, Czech Republic
| | - Colin J Henderson
- Division of Cancer Research, Medical Research Institute, Jacqui Wood Cancer Centre, University of Dundee, Dundee DD1 9SY, United Kingdom
| | - C Roland Wolf
- Division of Cancer Research, Medical Research Institute, Jacqui Wood Cancer Centre, University of Dundee, Dundee DD1 9SY, United Kingdom
| | - Heinz H Schmeiser
- Research Group Genetic Alterations in Carcinogenesis, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - David H Phillips
- Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment and Health, King's College London, 150 Stamford Street, London SE1 9NH, United Kingdom
| | - Eva Frei
- Division of Preventive Oncology, National Center for Tumour Diseases, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Volker M Arlt
- Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment and Health, King's College London, 150 Stamford Street, London SE1 9NH, United Kingdom
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Marchenko MM, Ketsa OV. [Functional activity of NADH-dependent reductase system in the liver microsomal fraction and Guerin's carcinoma in rats exposed to preliminary irradiation]. BIOMEDIT︠S︡INSKAI︠A︡ KHIMII︠A︡ 2014; 59:662-72. [PMID: 24511678 DOI: 10.18097/pbmc20135906662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Academic Contribution Register] [Indexed: 11/23/2022]
Abstract
The activity of liver and Guerin's carcinoma microsomal NADH-dependent reductase system has been investigated in tumor-bearing rats exposed to preliminary irradiation. Preliminary irradiation of rats (before transplantation of Guerin's carcinoma) resulted in the decrease of NADH-cytochrome b5 reductase activity and contents of cytochrome b5 in the Guerin's carcinoma microsomal fraction in the logarithmic phases of oncogenesis compared with the non-irradiated tumor-bearing rats. The effect of irradiation preceding transplantation of the tumor to rats results in the increase of enzymatic activities of liver microsomal NADH-cytochrome b5 reductase in the latent and logarithmic phases of tumor growth as compared with non-irradiated tumor-bearing rats. At the same time the contents of cytochrome b5 decreases. During longer periods after irradiation the investigated parameters approached to those in the group of non-irradiated tumor-bearing animals.
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Henderson CJ, Scheer N, Wolf CR. Advances in the generation of mouse models to elucidate the pathways of drug metabolism in rodents and man. Expert Rev Clin Pharmacol 2014; 2:105-9. [DOI: 10.1586/17512433.2.2.105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Indexed: 11/08/2022]
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Henderson CJ, McLaughlin LA, Finn RD, Ronseaux S, Kapelyukh Y, Wolf CR. A role for cytochrome b5 in the In vivo disposition of anticancer and cytochrome P450 probe drugs in mice. Drug Metab Dispos 2014; 42:70-7. [PMID: 24115751 PMCID: PMC3935460 DOI: 10.1124/dmd.113.055277] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Indexed: 01/15/2023] Open
Abstract
The role of microsomal cytochrome b5 (Cyb5) in defining the rate of drug metabolism and disposition has been intensely debated for several decades. Recently we described mouse models involving the hepatic or global deletion of Cyb5, demonstrating its central role in in vivo drug disposition. We have now used the cytochrome b5 complete null (BCN) model to determine the role of Cyb5 in the metabolism of ten pharmaceuticals metabolized by a range of cytochrome P450s, including five anticancer drugs, in vivo and in vitro. The extent to which metabolism was significantly affected by the absence of Cyb5 was substrate-dependent; AUC increased (75-245%) and clearance decreased (35-72%) for phenacetin, metoprolol, and chlorzoxazone. Tolbutamide disposition was not significantly altered by Cyb5 deletion, while for midazolam clearance was decreased by 66%. The absence of Cyb5 had no effect on gefitinib and paclitaxel disposition, while significant changes in the in vivo pharmacokinetics were measured for: cyclophosphamide [maximum plasma concentration (Cmax) and terminal half-life increased 55% and 40%, respectively], tamoxifen (AUClast and Cmax increased 370% and 233%, respectively), and anastrozole (AUC and terminal half-life increased 125% and 62%, respectively; clearance down 80%). These data provide strong evidence that both hepatic and extrahepatic Cyb5 levels are an important determinant of in vivo drug disposition catalyzed by a range of cytochrome P450s, including currently prescribed anticancer agents, and that individuality in Cyb5 expression could be a significant determinant in rates of drug disposition in man.
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Affiliation(s)
- Colin J Henderson
- Division of Cancer Research, Medical Research Institute, University of Dundee, and Ninewells Hospital and Medical School, Dundee, United Kingdom
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Macleod AK, Zang T, Riches Z, Henderson CJ, Wolf CR, Huang JTJ. A targeted in vivo SILAC approach for quantification of drug metabolism enzymes: regulation by the constitutive androstane receptor. J Proteome Res 2013; 13:866-74. [PMID: 24303842 PMCID: PMC3923450 DOI: 10.1021/pr400897t] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Academic Contribution Register] [Indexed: 01/10/2023]
Abstract
The modulation of drug metabolism enzyme (DME) expression by therapeutic agents is a central mechanism of drug-drug interaction and should be assessed as early as possible in preclinical drug development. Direct measurement of DME levels is typically achieved by Western blotting, qPCR, or microarray, but these techniques have their limitations; antibody cross-reactivity among highly homologous subfamilies creates ambiguity, while discordance between mRNA and protein expression undermines observations. The aim of this study was to design a simple targeted workflow by combining in vivo SILAC and label-free proteomics approaches for quantification of DMEs in mouse liver, facilitating a rapid and comprehensive evaluation of metabolic potential at the protein level. A total of 197 peptides, representing 51 Phase I and Phase II DMEs, were quantified by LC-MS/MS using targeted high resolution single ion monitoring (tHR/SIM) with a defined mass-to-charge and retention time window for each peptide. In a constitutive androstane receptor (Car) activated mouse model, comparison of tHR/SIM-in vivo SILAC with Western blotting for analysis of the expression of cytochromes P450 was favorable, with agreement in fold-change values between methods. The tHR/SIM-in vivo SILAC approach therefore permits the robust analysis of multiple DME in a single protein sample, with clear utility for the assessment of the drug-drug interaction potential of candidate therapeutic compounds.
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Affiliation(s)
- A Kenneth Macleod
- Jacqui Wood Cancer Centre, Medical Research Institute, Ninewells Hospital and Medical School, University of Dundee , James Arrott Drive, Dundee DD1 9SY, Scotland
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Pyrethroid activity-based probes for profiling cytochrome P450 activities associated with insecticide interactions. Proc Natl Acad Sci U S A 2013; 110:19766-71. [PMID: 24248381 DOI: 10.1073/pnas.1320185110] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Indexed: 11/18/2022] Open
Abstract
Pyrethroid insecticides are used to control diseases spread by arthropods. We have developed a suite of pyrethroid mimetic activity-based probes (PyABPs) to selectively label and identify P450s associated with pyrethroid metabolism. The probes were screened against pyrethroid-metabolizing and nonmetabolizing mosquito P450s, as well as rodent microsomes, to measure labeling specificity, plus cytochrome P450 oxidoreductase and b5 knockout mouse livers to validate P450 activation and establish the role for b5 in probe activation. Using PyABPs, we were able to profile active enzymes in rat liver microsomes and identify pyrethroid-metabolizing enzymes in the target tissue. These included P450s as well as related detoxification enzymes, notably UDP-glucuronosyltransferases, suggesting a network of associated pyrethroid-metabolizing enzymes, or "pyrethrome." Considering the central role P450s play in metabolizing insecticides, we anticipate that PyABPs will aid in the identification and profiling of P450s associated with insecticide pharmacology in a wide range of species, improving understanding of P450-insecticide interactions and aiding the development of unique tools for disease control.
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Hodek P, Koblihová J, Kizek R, Frei E, Arlt VM, Stiborová M. The relationship between DNA adduct formation by benzo[a]pyrene and expression of its activation enzyme cytochrome P450 1A1 in rat. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2013; 36:989-96. [PMID: 24095716 DOI: 10.1016/j.etap.2013.09.004] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Academic Contribution Register] [Received: 08/06/2013] [Revised: 09/04/2013] [Accepted: 09/05/2013] [Indexed: 06/02/2023]
Abstract
Benzo[a]pyrene (BaP) is a human carcinogen requiring metabolic activation prior to reaction with DNA. Cytochrome P450 (CYP) 1A1 is the most important hepatic and intestinal enzyme in both BaP activation and detoxification. CYP1A2 is also capable of oxidizing BaP, but to a lesser extent. The induction of CYP1A1/2 by BaP and/or β-naphthoflavone in liver and small intestine of rats was investigated. Both BaP and β-naphthoflavone induced CYP1A expression and increased enzyme activities in both organs. Moreover, the induction of CYP1A enzyme activities resulted in an increase in formation of BaP-DNA adducts detected by (32)P-postlabeling in rat liver and in the distal part of small intestine in vivo. The increases in CYP1A enzyme activity were also associated with bioactivation of BaP and elevated BaP-DNA adduct levels in ex vivo incubations of microsomes of both organs with DNA and BaP. These findings indicate a stimulating effect of both compounds on BaP-induced carcinogenesis.
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Affiliation(s)
- Petr Hodek
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 Prague 2, Czech Republic
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Henderson CJ, McLaughlin LA, Wolf CR. Evidence that cytochrome b5 and cytochrome b5 reductase can act as sole electron donors to the hepatic cytochrome P450 system. Mol Pharmacol 2013; 83:1209-17. [PMID: 23530090 DOI: 10.1124/mol.112.084616] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Indexed: 01/08/2023] Open
Abstract
We previously described the development of genetic models to study the in vivo functions of the hepatic cytochrome P450 (P450) system, through the hepatic deletion of either cytochrome P450 oxidoreductase [POR; HRN (hepatic reductase null) line] or cytochrome b(5) [HBN (hepatic cytochrome b(5) null) line]. However, HRN mice still exhibit low levels of mono-oxygenase activity in spite of the absence of detectable reductase protein. To investigate whether this is because cytochrome b(5) and cytochrome b(5) reductase can act as the sole electron donor to the P450 system, we crossed HRN with HBN mice to generate a line lacking hepatic expression of both electron donors (HBRN). HBRN mice exhibited exacerbation of the phenotypic characteristics of the HRN line: liver enlargement, hepatosteatosis, and increased expression of certain P450s. Also, drug metabolizing activities in vitro were further reduced relative to the HRN model, in some cases to undetectable levels. Pharmacokinetic studies in vivo demonstrated that midazolam half-life, C(max), and area under the concentration-time curve were increased, and clearance was decreased, to a greater extent in the HBRN line than in either the HBN or HRN model. Microsomal incubations using NADPH concentrations below the apparent K(m) of cytochrome b(5) reductase, but well above that for POR, led to the virtual elimination of 7-benzyloxyquinoline turnover in HRN samples. These data provide strong evidence that cytochrome b(5)/cytochrome b(5) reductase can act as a sole electron donor to the P450 system in vitro and in vivo.
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Affiliation(s)
- Colin J Henderson
- Division of Cancer Research, Medical Research Institute, University of Dundee, Jacqui Wood Cancer Centre, Ninewells Hospitaland Medical School, Dundee, United Kingdom
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Ahuja S, Jahr N, Im SC, Vivekanandan S, Popovych N, Le Clair SV, Huang R, Soong R, Xu J, Yamamoto K, Nanga RP, Bridges A, Waskell L, Ramamoorthy A. A model of the membrane-bound cytochrome b5-cytochrome P450 complex from NMR and mutagenesis data. J Biol Chem 2013; 288:22080-95. [PMID: 23709268 DOI: 10.1074/jbc.m112.448225] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Indexed: 01/08/2023] Open
Abstract
Microsomal cytochrome b5 (cytb5) is a membrane-bound protein that modulates the catalytic activity of its redox partner, cytochrome P4502B4 (cytP450). Here, we report the first structure of full-length rabbit ferric microsomal cytb5 (16 kDa), incorporated in two different membrane mimetics (detergent micelles and lipid bicelles). Differential line broadening of the cytb5 NMR resonances and site-directed mutagenesis data were used to characterize the cytb5 interaction epitope recognized by ferric microsomal cytP450 (56 kDa). Subsequently, a data-driven docking algorithm, HADDOCK (high ambiguity driven biomolecular docking), was used to generate the structure of the complex between cytP4502B4 and cytb5 using experimentally derived restraints from NMR, mutagenesis, and the double mutant cycle data obtained on the full-length proteins. Our docking and experimental results point to the formation of a dynamic electron transfer complex between the acidic convex surface of cytb5 and the concave basic proximal surface of cytP4502B4. The majority of the binding energy for the complex is provided by interactions between residues on the C-helix and β-bulge of cytP450 and residues at the end of helix α4 of cytb5. The structure of the complex allows us to propose an interprotein electron transfer pathway involving the highly conserved Arg-125 on cytP450 serving as a salt bridge between the heme propionates of cytP450 and cytb5. We have also shown that the addition of a substrate to cytP450 likely strengthens the cytb5-cytP450 interaction. This study paves the way to obtaining valuable structural, functional, and dynamic information on membrane-bound complexes.
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Affiliation(s)
- Shivani Ahuja
- Department of Chemistry and Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, USA
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Munro AW, Girvan HM, Mason AE, Dunford AJ, McLean KJ. What makes a P450 tick? Trends Biochem Sci 2013; 38:140-50. [DOI: 10.1016/j.tibs.2012.11.006] [Citation(s) in RCA: 128] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 08/25/2012] [Revised: 11/15/2012] [Accepted: 11/21/2012] [Indexed: 12/31/2022]
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Riddick DS, Ding X, Wolf CR, Porter TD, Pandey AV, Zhang QY, Gu J, Finn RD, Ronseaux S, McLaughlin LA, Henderson CJ, Zou L, Flück CE. NADPH-cytochrome P450 oxidoreductase: roles in physiology, pharmacology, and toxicology. Drug Metab Dispos 2013; 41:12-23. [PMID: 23086197 PMCID: PMC3533425 DOI: 10.1124/dmd.112.048991] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 09/10/2012] [Accepted: 10/19/2012] [Indexed: 01/16/2023] Open
Abstract
This is a report on a symposium sponsored by the American Society for Pharmacology and Experimental Therapeutics and held at the Experimental Biology 2012 meeting in San Diego, California, on April 25, 2012. The symposium speakers summarized and critically evaluated our current understanding of the physiologic, pharmacological, and toxicological roles of NADPH-cytochrome P450 oxidoreductase (POR), a flavoprotein involved in electron transfer to microsomal cytochromes P450 (P450), cytochrome b(5), squalene mono-oxygenase, and heme oxygenase. Considerable insight has been derived from the development and characterization of mouse models with conditional Por deletion in particular tissues or partial suppression of POR expression in all tissues. Additional mouse models with global or conditional hepatic deletion of cytochrome b(5) are helping to clarify the P450 isoform- and substrate-specific influences of cytochrome b(5) on P450 electron transfer and catalytic function. This symposium also considered studies using siRNA to suppress POR expression in a hepatoma cell-culture model to explore the basis of the hepatic lipidosis phenotype observed in mice with conditional deletion of Por in liver. The symposium concluded with a strong translational perspective, relating the basic science of human POR structure and function to the impacts of POR genetic variation on human drug and steroid metabolism.
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Affiliation(s)
- David S Riddick
- Department of Pharmacology and Toxicology, Medical Sciences Building, University of Toronto, Toronto, Ontario, Canada M5S 1A8.
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Peng HM, Auchus RJ. The action of cytochrome b(5) on CYP2E1 and CYP2C19 activities requires anionic residues D58 and D65. Biochemistry 2012. [PMID: 23193974 DOI: 10.1021/bi301384n] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Indexed: 11/30/2022]
Abstract
The capacity of cytochrome b(5) (b(5)) to influence cytochrome P450 activities has been extensively studied and physiologically validated. Apo-b(5) enhances the activities of CYP3A4, CYP2A6, CYP2C19, and CYP17A1 but not that of CYP2E1 or CYP2D6, suggesting that the b(5) interaction varies among P450s. We previously showed that b(5) residues E48 and E49 are required to stimulate the 17,20-lyase activity of CYP17A1, but these same residues might not mediate b(5) activation of other P450 reactions, such as CYP2E1-catalyzed oxygenations, which are insensitive to apo-b(5). Using purified P450, b(5), and reductase (POR) in reconstituted assays, the D58G/D65G double mutation, of residues located in a hydrophilic α-helix of b(5), totally abolished the ability to stimulate CYP2E1-catalyzed chlorzoxazone 6-hydroxylation. In sharp contrast, the D58G/D65G double mutation retained the full ability to stimulate the 17,20-lyase activity of CYP17A1. The D58G/D65G double mutation competes poorly with wild-type b(5) for binding to the CYP2E1·POR complex yet accepts electrons from POR at a similar rate. Furthermore, the phospholipid composition markedly influences P450 turnover and b(5) stimulation and specificity, particularly for CYP17A1, in the following order: phosphatidylserine > phosphatidylethanolamine > phosphatidylcholine. The D58G/D65G double mutation also failed to stimulate CYP2C19-catalyzed (S)-mephenytoin 4-hydroxylation, whereas the E48G/E49G double mutation stimulated these activities of CYP2C19 and CYP2E1 equivalent to wild-type b(5). We conclude that b(5) residues D58 and D65 are essential for the stimulation of CYP2E1 and CYP2C19 activities and that the phospholipid composition significantly influences the b(5)-P450 interaction. At least two surfaces of b(5) differentially influence P450 activities, and the critical residues for individual P450 reactions cannot be predicted from sensitivity to apo-b(5) alone.
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Affiliation(s)
- Hwei-Ming Peng
- Division of Metabolism, Endocrinology, and Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA
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