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Liu K, Hughes JMX, Hay S, Scrutton NS. Liver microsomal lipid enhances the activity and redox coupling of colocalized cytochrome P450 reductase-cytochrome P450 3A4 in nanodiscs. FEBS J 2017; 284:2302-2319. [PMID: 28618157 PMCID: PMC5575521 DOI: 10.1111/febs.14129] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 06/01/2017] [Accepted: 06/05/2017] [Indexed: 01/22/2023]
Abstract
The haem-containing mono-oxygenase cytochrome P450 3A4 (CYP3A4) and its redox partner NADPH-dependent cytochrome P450 oxidoreductase (CPR) are among the most important enzymes in human liver for metabolizing drugs and xenobiotic compounds. They are membrane-bound in the endoplasmic reticulum (ER). How ER colocalization and the complex ER phospholipid composition influence enzyme activity are not well understood. CPR and CYP3A4 were incorporated into phospholipid bilayer nanodiscs, both singly, and together in a 1 : 1 ratio, to investigate the significance of membrane insertion and the influence of varying membrane composition on steady-state reaction kinetics. Reaction kinetics were analysed using a fluorimetric assay with 7-benzyloxyquinoline as substrate for CYP3A4. Full activity of the mono-oxygenase system, with electron transfer from NADPH via CPR, could only be reconstituted when CPR and CYP3A4 were colocalized within the same nanodiscs. No activity was observed when CPR and CYP3A4 were each incorporated separately into nanodiscs then mixed together, or when soluble forms of CPR were mixed with preassembled CYP3A4-nanodiscs. Membrane integration and colocalization are therefore essential for electron transfer. Liver microsomal lipid had an enhancing effect compared with phosphatidylcholine on the activity of CPR alone in nanodiscs, and a greater enhancing effect on the activity of CPR-CYP3A4 nanodisc complexes, which was not matched by a phospholipid mixture designed to mimic the ER composition. Furthermore, liver lipid enhanced redox coupling within the system. Thus, natural ER lipids possess properties or include components important for enhanced catalysis by CPR-CYP3A4 nanodisc complexes. Our findings demonstrate the importance of using natural lipid preparations for the detailed analysis of membrane protein activity.
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Affiliation(s)
- Kang‐Cheng Liu
- Centre for Synthetic Biology of Fine and Speciality Chemicals (SYNBIOCHEM)School of ChemistryManchester Institute of BiotechnologyThe University of ManchesterUK
| | - John M. X. Hughes
- Centre for Synthetic Biology of Fine and Speciality Chemicals (SYNBIOCHEM)School of ChemistryManchester Institute of BiotechnologyThe University of ManchesterUK
| | - Sam Hay
- Centre for Synthetic Biology of Fine and Speciality Chemicals (SYNBIOCHEM)School of ChemistryManchester Institute of BiotechnologyThe University of ManchesterUK
| | - Nigel S. Scrutton
- Centre for Synthetic Biology of Fine and Speciality Chemicals (SYNBIOCHEM)School of ChemistryManchester Institute of BiotechnologyThe University of ManchesterUK
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Abstract
Purpose of Review We provide an overview of the current knowledge on cytochrome P450-mediated metabolism organized as metabolons and factors that facilitate their stabilization. Essential parameters will be discussed including those that are commonly disregarded using the dhurrin metabolon from Sorghum bicolor as a case study. Recent Findings Sessile plants control their metabolism to prioritize their resources between growth and development, or defense. This requires fine-tuned complex dynamic regulation of the metabolic networks involved. Within the recent years, numerous studies point to the formation of dynamic metabolons playing a major role in controlling the metabolic fluxes within such networks. Summary We propose that P450s and their partners interact and associate dynamically with POR, which acts as a charging station possibly in concert with Cytb5. Solvent environment, lipid composition, and non-catalytic proteins guide metabolon formation and thereby activity, which have important implications for synthetic biology approaches aiming to produce high-value specialized metabolites in heterologous hosts.
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Affiliation(s)
- Jean-Etienne Bassard
- Plant Biochemistry Laboratory, Center for Synthetic Biology, VILLUM Research Center “Plant Plasticity,” Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Copenhagen Denmark
| | - Birger Lindberg Møller
- Plant Biochemistry Laboratory, Center for Synthetic Biology, VILLUM Research Center “Plant Plasticity,” Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Copenhagen Denmark
- Carlsberg Research Laboratory, Gamle Carlsberg Vej 10, DK-1799 Copenhagen V, Denmark
| | - Tomas Laursen
- Plant Biochemistry Laboratory, Center for Synthetic Biology, VILLUM Research Center “Plant Plasticity,” Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Copenhagen Denmark
- Feedstocks Division, Joint BioEnergy Institute, Emeryville, CA 94608 USA
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Brignac-Huber LM, Park JW, Reed JR, Backes WL. Cytochrome P450 Organization and Function Are Modulated by Endoplasmic Reticulum Phospholipid Heterogeneity. Drug Metab Dispos 2016; 44:1859-1866. [PMID: 27233287 DOI: 10.1124/dmd.115.068981] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 05/26/2016] [Indexed: 11/22/2022] Open
Abstract
Cytochrome P450s (P450s) comprise a superfamily of proteins that catalyze numerous monooxygenase reactions in animals, plants, and bacteria. In eukaryotic organisms, these proteins not only carry out reactions necessary for the metabolism of endogenous compounds, but they are also important in the oxidation of exogenous drugs and other foreign compounds. Eukaryotic P450 system proteins generally reside in membranes, primarily the endoplasmic reticulum or the mitochondrial membrane. These membranes provide a scaffold for the P450 system proteins that facilitate interactions with their redox partners as well as other P450s. This review focuses on the ability of specific lipid components to influence P450 activities, as well as the role of the membrane in P450 function. These studies have shown that P450s and NADPH-cytochrome P450 reductase appear to selectively associate with specific phospholipids and that these lipid-protein interactions influence P450 activities. Finally, because of the heterogeneous nature of the endoplasmic reticulum as well as other biologic membranes, the phospholipids are not arranged randomly but associate to generate lipid microdomains. Together, these characteristics can affect P450 function by 1) altering the conformation of the proteins, 2) influencing the P450 interactions with their redox partners, and 3) affecting the localization of the proteins into specific membrane microdomains.
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Affiliation(s)
- Lauren M Brignac-Huber
- Department of Pharmacology and Experimental Therapeutics and the Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, New Orleans, Louisiana
| | - Ji Won Park
- Department of Pharmacology and Experimental Therapeutics and the Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, New Orleans, Louisiana
| | - James R Reed
- Department of Pharmacology and Experimental Therapeutics and the Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, New Orleans, Louisiana
| | - Wayne L Backes
- Department of Pharmacology and Experimental Therapeutics and the Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, New Orleans, Louisiana
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Cell-penetrating compounds preferentially bind glycosaminoglycans over plasma membrane lipids in a charge density- and stereochemistry-dependent manner. Biophys Chem 2015; 207:40-50. [DOI: 10.1016/j.bpc.2015.08.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 08/14/2015] [Accepted: 08/17/2015] [Indexed: 11/19/2022]
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Brignac-Huber LM, Reed JR, Eyer MK, Backes WL. Relationship between CYP1A2 localization and lipid microdomain formation as a function of lipid composition. Drug Metab Dispos 2013; 41:1896-905. [PMID: 23963955 DOI: 10.1124/dmd.113.053611] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Cytochrome P450 (P450) function requires the interaction of P450 and NADPH-cytochrome P450 reductase (CPR) in membranes, and is frequently studied using reconstituted systems composed solely of phosphatidylcholine. There is increasing evidence that other endoplasmic reticulum (ER) lipids can affect P450 structure, activity, and interactions with CPR. Some of these lipid effects have been attributed to the formation of organized liquid-ordered (l(o)) domains. The goal of this study was to determine if l(o) domains were formed in P450 reconstituted systems mimicking the ER membrane. CYP1A2, when incorporated in "ER-like" lipid vesicles, displayed detergent insolubility after treatment with Brij 98 and centrifugation in a sucrose gradient. Lipid probes were employed to identify domain formation in both ER-like vesicles and model membranes known to form l(o) domains. Changes in fluorescence resonance energy transfer (FRET) using an established donor/acceptor FRET pair in both ER-like and model l(o)-forming systems demonstrated the coexistence of l(o)- and liquid-disordered domains as a function of cholesterol and sphingomyelin content. Similarly, 6-dodecanoyl-2-dimethylaminonaphthalene (laurdan), a probe that reports on membrane organization, showed that cholesterol and sphingomyelin increased membrane order. Finally, brominated-phosphatidylcholine allowed for monitoring of the location of both CPR and CYP1A2 within the l(o) regions of ER-like systems. Taken together, the results demonstrate that ER-like vesicles generate microdomains, and both CYP1A2 and CPR predominantly localize into l(o) membrane regions. Probe fluorescent responses suggest that lipid microdomains form in these vesicles whether or not enzymes are included in the reconstituted systems. Thus, it does not appear that the proteins are critical for stabilizing l(o) domains.
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Affiliation(s)
- Lauren M Brignac-Huber
- Department of Pharmacology and Experimental Therapeutics, Stanley S. Scott Cancer Center, Louisiana State University Health Science Center, New Orleans, Louisiana
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CYP2J2 and CYP2C19 are the major enzymes responsible for metabolism of albendazole and fenbendazole in human liver microsomes and recombinant P450 assay systems. Antimicrob Agents Chemother 2013; 57:5448-56. [PMID: 23959307 DOI: 10.1128/aac.00843-13] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Albendazole and fenbendazole are broad-spectrum anthelmintics that undergo extensive metabolism to form hydroxyl and sulfoxide metabolites. Although CYP3A and flavin-containing monooxygenase have been implicated in sulfoxide metabolite formation, the enzymes responsible for hydroxyl metabolite formation have not been identified. In this study, we used human liver microsomes and recombinant cytochrome P450s (P450s) to characterize the enzymes involved in the formation of hydroxyalbendazole and hydroxyfenbendazole from albendazole and fenbendazole, respectively. Of the 10 recombinant P450s, CYP2J2 and/or CYP2C19 was the predominant enzyme catalyzing the hydroxylation of albendazole and fenbendazole. Albendazole hydroxylation to hydroxyalbendazole is primarily mediated by CYP2J2 (0.34 μl/min/pmol P450, which is a rate 3.9- and 8.1-fold higher than the rates for CYP2C19 and CYP2E1, respectively), whereas CYP2C19 and CYP2J2 contributed to the formation of hydroxyfenbendazole from fenbendazole (2.68 and 1.94 μl/min/pmol P450 for CYP2C19 and CYP2J2, respectively, which are rates 11.7- and 8.4-fold higher than the rate for CYP2D6). Correlation analysis between the known P450 enzyme activities and the rate of hydroxyalbendazole and hydroxyfenbendazole formation in samples from 14 human liver microsomes showed that albendazole hydroxylation correlates with CYP2J2 activity and fenbendazole hydroxylation correlates with CYP2C19 and CYP2J2 activities. These findings were supported by a P450 isoform-selective inhibition study in human liver microsomes. In conclusion, our data for the first time suggest that albendazole hydroxylation is primarily catalyzed by CYP2J2, whereas fenbendazole hydroxylation is preferentially catalyzed by CYP2C19 and CYP2J2. The present data will be useful in understanding the pharmacokinetics and drug interactions of albendazole and fenbendazole in vivo.
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Ghosh MC, Ray AK. Membrane phospholipid augments cytochrome P4501a enzymatic activity by modulating structural conformation during detoxification of xenobiotics. PLoS One 2013; 8:e57919. [PMID: 23469105 PMCID: PMC3585281 DOI: 10.1371/journal.pone.0057919] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Accepted: 01/27/2013] [Indexed: 12/08/2022] Open
Abstract
Cytochrome P450 is a superfamily of membrane-bound hemoprotein that gets involved with the degradation of xenobiotics and internal metabolites. Accumulated body of evidence indicates that phospholipids play a crucial role in determining the enzymatic activity of cytochrome P450 in the microenvironment by modulating its structure during detoxification; however, the structure-function relationship of cytochrome P4501A, a family of enzymes responsible for degrading lipophilic aromatic hydrocarbons, is still not well defined. Inducibility of cytochrome P4501A in cultured catfish hepatocytes in response to carbofuran, a widely used pesticide around the world, was studied earlier in our laboratory. In this present investigation, we observed that treating catfish with carbofuran augmented total phospholipid in the liver. We examined the role of phospholipid on the of cytochrome P4501A-marker enzyme which is known as ethoxyresorufin-O-deethylase (EROD) in the context of structure and function. We purified the carbofuran-induced cytochrome P4501A protein from catfish liver. Subsequently, we examined the enzymatic activity of purified P4501A protein in the presence of phospholipid, and studied how the structure of purified protein was influenced in the phospholipid environment. Membrane phospholipid appeared to accelerate the enzymatic activity of EROD by changing its structural conformation and thus controlling the detoxification of xenobiotics. Our study revealed the missing link of how the cytochrome P450 restores its enzymatic activity by changing its structural conformation in the phospholipid microenvironment.
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Affiliation(s)
- Manik C Ghosh
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America.
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Brignac-Huber L, Reed JR, Backes WL. Organization of NADPH-cytochrome P450 reductase and CYP1A2 in the endoplasmic reticulum--microdomain localization affects monooxygenase function. Mol Pharmacol 2010; 79:549-57. [PMID: 21156755 DOI: 10.1124/mol.110.068817] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cytochrome P450 is part of an electron transport chain found in the endoplasmic reticulum (ER), with its catalytic function requiring interactions with NADPH-cytochrome P450 reductase (CPR). The goals of this study were to examine how the P450 system proteins are organized in the membrane and to determine whether they are distributed in detergent-resistant lipid microdomains (DRM). Isolated liver microsomes from untreated rabbits were treated with 1% Brij 98, and DRMs were isolated via sucrose gradient centrifugation. Lipid analysis showed that DRM fractions were enriched in cholesterol and sphingomyelin, similar to that found with plasma membrane DRMs. Approximately 73% of CYP1A2 and 68% of CPR resided in DRM fractions, compared with only 33% of total ER proteins. These DRMs were found to be cholesterol-dependent: CPR and CYP1A2 migrated to the more dense regions of the sucrose gradient after cholesterol depletion. CYP1A2 function was studied in three purified lipid vesicles consisting of 1) phosphatidylcholine (V-PC), 2) lipids with a composition similar to ER lipids (V-ER), and 3) lipids with a composition similar to the DRM fractions (V-DRM). Each system showed similar substrate binding characteristics. However, when the association between CPR and CYP1A2 was measured, V-ER and V-DRM liposomes produced lower apparent K(m) values compared with V-PC without any significant change in V(max). These findings suggest that CYP1A2 and CPR reside in ER-DRMs and that the unique lipid components of these domains enhance CYP1A2 substrate metabolism through greater efficiency in CPR-CYP1A2 binding.
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Affiliation(s)
- Lauren Brignac-Huber
- Department of Pharmacology, Stanley S. Scott Cancer Center, Louisiana State University, New Orleans, LA 70112, USA
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Jang HH, Kim DH, Ahn T, Yun CH. Functional and conformational modulation of human cytochrome P450 1B1 by anionic phospholipids. Arch Biochem Biophys 2010; 493:143-50. [DOI: 10.1016/j.abb.2009.10.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2009] [Revised: 10/20/2009] [Accepted: 10/21/2009] [Indexed: 10/20/2022]
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