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Loos NHC, Beijnen JH, Schinkel AH. The Mechanism-Based Inactivation of CYP3A4 by Ritonavir: What Mechanism? Int J Mol Sci 2022; 23:ijms23179866. [PMID: 36077262 PMCID: PMC9456214 DOI: 10.3390/ijms23179866] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Revised: 08/24/2022] [Accepted: 08/26/2022] [Indexed: 11/16/2022] Open
Abstract
Ritonavir is the most potent cytochrome P450 (CYP) 3A4 inhibitor in clinical use and is often applied as a booster for drugs with low oral bioavailability due to CYP3A4-mediated biotransformation, as in the treatment of HIV (e.g., lopinavir/ritonavir) and more recently COVID-19 (Paxlovid or nirmatrelvir/ritonavir). Despite its clinical importance, the exact mechanism of ritonavir-mediated CYP3A4 inactivation is still not fully understood. Nonetheless, ritonavir is clearly a potent mechanism-based inactivator, which irreversibly blocks CYP3A4. Here, we discuss four fundamentally different mechanisms proposed for this irreversible inactivation/inhibition, namely the (I) formation of a metabolic-intermediate complex (MIC), tightly coordinating to the heme group; (II) strong ligation of unmodified ritonavir to the heme iron; (III) heme destruction; and (IV) covalent attachment of a reactive ritonavir intermediate to the CYP3A4 apoprotein. Ritonavir further appears to inactivate CYP3A4 and CYP3A5 with similar potency, which is important since ritonavir is applied in patients of all ethnicities. Although it is currently not possible to conclude what the primary mechanism of action in vivo is, it is unlikely that any of the proposed mechanisms are fundamentally wrong. We, therefore, propose that ritonavir markedly inactivates CYP3A through a mixed set of mechanisms. This functional redundancy may well contribute to its overall inhibitory efficacy.
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Affiliation(s)
- Nancy H. C. Loos
- The Netherlands Cancer Institute, Division of Pharmacology, 1066 CX Amsterdam, The Netherlands
| | - Jos H. Beijnen
- Faculty of Science, Department of Pharmaceutical Sciences, Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht University, 3584 CS Utrecht, The Netherlands
- The Netherlands Cancer Institute, Division of Pharmacy and Pharmacology, 1066 CX Amsterdam, The Netherlands
| | - Alfred H. Schinkel
- The Netherlands Cancer Institute, Division of Pharmacology, 1066 CX Amsterdam, The Netherlands
- Correspondence: ; Tel.: +31-205122046
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Abstract
Significance: During aging, excessive production of reactive species in the liver leads to redox imbalance with consequent oxidative damage and impaired organ homeostasis. Nevertheless, slight amounts of reactive species may modulate several transcription factors, acting as second messengers and regulating specific signaling pathways. These redox-dependent alterations may impact the age-associated decline in liver regeneration. Recent Advances: In the last few decades, relevant findings related to redox alterations in the aging liver were investigated. Consistently, recent research broadened understanding of redox modifications and signaling related to liver regeneration. Other than reporting the effect of oxidative stress, epigenetic and post-translational modifications, as well as modulation of specific redox-sensitive cellular signaling, were described. Among them, the present review focuses on Wnt/β-catenin, the nuclear factor (erythroid-derived 2)-like 2 (NRF2), members of the Forkhead box O (FoxO) family, and the p53 tumor suppressor. Critical Issues: Even though alteration in redox homeostasis occurs both in aging and in impaired liver regeneration, the associative mechanisms are not clearly defined. Of note, antioxidants are not effective in slowing hepatic senescence, and do not clearly improve liver repopulation after hepatectomy or transplant in humans. Future Directions: Further investigations are needed to define mutual redox-dependent molecular pathways involved both in aging and in the decline of liver regeneration. Preclinical studies aimed at the characterization of these pathways would define possible therapeutic targets for human trials. Antioxid. Redox Signal. 35, 832-847.
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Affiliation(s)
- Francesco Bellanti
- Department of Medical and Surgical Sciences, University of Foggia, Foggia, Italy
| | - Gianluigi Vendemiale
- Department of Medical and Surgical Sciences, University of Foggia, Foggia, Italy
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Wei W, Li R, Liu Q, Devanathadesikan Seshadri V, Veeraraghavan VP, Surapaneni KM, Rengarajan T. Amelioration of oxidative stress, inflammation and tumor promotion by Tin oxide-Sodium alginate-Polyethylene glycol-Allyl isothiocyanate nanocomposites on the 1,2-Dimethylhydrazine induced colon carcinogenesis in rats. ARAB J CHEM 2021. [DOI: 10.1016/j.arabjc.2021.103238] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
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Trivedi A, Wahlstrom J, Mackowski M, Dutta S, Lee E. Pharmacokinetics, Disposition, and Biotransformation of [ 14C]Omecamtiv Mecarbil in Healthy Male Subjects after a Single Intravenous or Oral Dose. Drug Metab Dispos 2021; 49:619-628. [PMID: 34011533 DOI: 10.1124/dmd.121.000444] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 04/26/2021] [Indexed: 11/22/2022] Open
Abstract
Omecamtiv mecarbil (OM) is a novel cardiac myosin activator that is currently in clinical development for the treatment of heart failure. The absorption and disposition of [14C]OM (60 µCi) were studied after a single intravenous infusion (35 mg over 1 hour) or oral solution dose (35 mg) in 14 healthy male subjects. Mean recovery of the administered [14C]OM dose was 85.1% and 86.5% over 336 hours for the intravenous and oral routes, respectively. After intravenous dosing, 47.8% and 37.3% of the dose was recovered in urine and feces, respectively; after oral dosing, 48.6% and 38.0% was recovered in urine and feces, respectively. Unchanged OM accounted for a minor percentage of radioactivity in urine (mean 7.7% of dose) and feces (mean 4.1% of dose) across all subjects. The major metabolites recovered in urine and feces were M3 (decarbamoylation product) and sequential metabolite M4 (lactam of M3), which accounted for means of 26.5% and 11.6% of the administered dose, respectively. The CYP4 family of enzymes was primarily responsible for the formation of M3 based on in vitro studies. Other metabolic pathways accounted for 14.9% of the administered dose. In pooled plasma, OM, M3, and M4 accounted for 83.8%, 6.0%, and 3.3% of the total [14C]OM-related materials. No other plasma metabolites constituted more than 3% of the administered dose. The bioavailability for OM solution was 93.5% after rapid and extensive absorption. SIGNIFICANCE STATEMENT: This study characterized the absorption and disposition of OM, a novel small molecule being developed for the treatment of heart failure. OM was primarily cleared through metabolism by the CYP4 family through oxidative cleavage of a terminal carbamate moiety that resembles hydrolysis.
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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: 3.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar 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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Liu J, Ma X, LingWang. Modulating effect of graphine oxide loaded hesperidin nanocomposite on the 1,2-dimethylhydrazine provoked colon carcinogenesis in rats via inhibiting the iNOS and COX-2 pathways. ARAB J CHEM 2020. [DOI: 10.1016/j.arabjc.2020.06.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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Mendieta-Wejebe JE, Silva-Trujillo A, Bello M, Mendoza-Figueroa HL, Galindo-Alvarez NL, Albores A, Tamay-Cach F, Rosales-Hernández MC, Romero-Castro A, Correa-Basurto J. Exploring the biotransformation of N-(2-hydroxyphenyl)-2-propylpentanamide (an aryl valproic acid derivative) by CYP2C11, using in silico predictions and in vitro studies. J Pharm Pharmacol 2020; 72:938-955. [PMID: 32307724 DOI: 10.1111/jphp.13270] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 03/21/2020] [Indexed: 01/22/2023]
Abstract
OBJECTIVES N-(2-hydroxyphenyl)-2-propylpentanamide (HO-AAVPA), a derivative of valproic acid (VPA), has been proposed as a potential anticancer agent due to its improved antiproliferative effects in some cancer cell lines. Although there is evidence that VPA is metabolized by cytochrome P450 2C11 rat isoform, HO-AAVPA CYP-mediated metabolism has not yet been fully explored. Therefore, in this work, the biotransformation of HO-AAVPA by CYP2C11 was investigated. METHODS Kinetic parameters and spectral interaction between HO-AAVPA and CYP were evaluated using rat liver microsomes. The participation of CYP2C11 in metabolism of HO-AAVPA was confirmed by cimetidine (CIM) inhibition assay. Docking and molecular dynamics simulations coupled to MMGBSA methods were used in theoretical study. KEY FINDINGS HO-AAVPA is metabolized by CYP enzymes (KM = 38.94 µm), yielding a hydroxylated metabolite according to its HPLC retention time (5.4 min) and MS analysis (252.2 m/z). In addition, CIM inhibition in rat liver microsomes (Ki = 59.23 µm) confirmed that CYP2C11 is mainly involved in HO-AAVPA metabolism. Furthermore, HO-AAVPA interacts with CYP2C11 as a type I ligand. HO-AAVPA is stabilized at the CYP2C11 ligand recognition site through a map of interactions similar to other typical CYP2C11 substrates. CONCLUSION Therefore, rat liver CYP2C11 isoform is able to metabolize HO-AAVPA.
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Affiliation(s)
- Jessica Elena Mendieta-Wejebe
- Laboratorio de Biofísica y Biocatálisis, Escuela Superior de Medicina, Instituto Politécnico Nacional, Ciudad de México, México
| | - Arianna Silva-Trujillo
- Laboratorio de Biofísica y Biocatálisis, Escuela Superior de Medicina, Instituto Politécnico Nacional, Ciudad de México, México
| | - Martiniano Bello
- Laboratorio de Diseño y Desarrollo de Nuevos Fármacos e Innovación Biotecnológica (Laboratory for the Design and Development of New Drugs and Biotechnological Innovation), Escuela Superior de Medicina, Instituto Politécnico Nacional, Ciudad de México, México
| | - Humberto L Mendoza-Figueroa
- Laboratorio de Diseño y Desarrollo de Nuevos Fármacos e Innovación Biotecnológica (Laboratory for the Design and Development of New Drugs and Biotechnological Innovation), Escuela Superior de Medicina, Instituto Politécnico Nacional, Ciudad de México, México
| | - Norma Lizeth Galindo-Alvarez
- Laboratorio de Diseño y Desarrollo de Nuevos Fármacos e Innovación Biotecnológica (Laboratory for the Design and Development of New Drugs and Biotechnological Innovation), Escuela Superior de Medicina, Instituto Politécnico Nacional, Ciudad de México, México
| | - Arnulfo Albores
- Sección de Toxicología, Centro de Investigación y de Estudios Avanzados, Instituto Politécnico Nacional, Ciudad de México, México
| | - Feliciano Tamay-Cach
- Laboratorio de Investigación Bioquímica, Escuela Superior de Medicina, Instituto Politécnico Nacional, Ciudad de México, México
| | | | | | - José Correa-Basurto
- Laboratorio de Diseño y Desarrollo de Nuevos Fármacos e Innovación Biotecnológica (Laboratory for the Design and Development of New Drugs and Biotechnological Innovation), Escuela Superior de Medicina, Instituto Politécnico Nacional, Ciudad de México, México
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Jamwal R, de la Monte SM, Ogasawara K, Adusumalli S, Barlock BB, Akhlaghi F. Nonalcoholic Fatty Liver Disease and Diabetes Are Associated with Decreased CYP3A4 Protein Expression and Activity in Human Liver. Mol Pharm 2018; 15:2621-2632. [PMID: 29792708 DOI: 10.1021/acs.molpharmaceut.8b00159] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Nonalcoholic fatty liver disease (NAFLD) is a major cause of chronic liver disease in the Western population. We investigated the association of nonalcoholic fatty liver disease (NAFLD) and diabetes mellitus on CYP3A4 activity in human liver tissue from brain dead donors ( n = 74). Histopathologically graded livers were grouped into normal ( n = 24), nonalcoholic fatty liver (NAFL, n = 26), and nonalcoholic steatohepatitis (NASH, n = 24) categories. The rate of conversion of midazolam to its 1-hydroxy metabolite was used to assess in vitro CYP3A4 activity in human liver microsomes (HLM). A proteomics approach was utilized to quantify the protein expression of CYP3A4 and related enzymes. Moreover, a physiologically based pharmacokinetic (PBPK) model was developed to allow prediction of midazolam concentration in NAFL and NASH livers. CYP3A4 activity in NAFL and NASH was 1.9- and 3.1-fold ( p < 0.05) lower than normal donors, respectively. Intrinsic clearance (CLint) was 2.7- ( p < 0.05) and 4.1-fold ( p < 0.01) lower in donors with NAFL and NASH, respectively. CYP3A4 protein expression was significantly lower in NAFL and NASH donors ( p < 0.05) and accounted for significant midazolam hydroxylation variability in a multiple linear regression analysis (β = 0.869, r2 = 0.762, P < 0.01). Diabetes was also associated with decreased CYP3A4 activity and protein expression. Both midazolam CLint and CYP3A4 protein abundance decreased significantly with increase in hepatic fat accumulation. Age and gender did not exhibit any significant association with the observed alterations. Predicted midazolam exposure was 1.7- and 2.3-fold higher for NAFL and NASH, respectively, which may result in a longer period of sedation in these disease-states. Data suggests that NAFLD and diabetes are associated with the decreased hepatic CYP3A4 activity. Thus, further evaluation of clinical consequences of these findings on the efficacy and safety of CYP3A4 substrates is warranted.
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Affiliation(s)
- Rohitash Jamwal
- Biomedical and Pharmaceutical Sciences, College of Pharmacy , University of Rhode Island , Kingston , Rhode Island 02881 , United States
| | - Suzanne M de la Monte
- Departments of Medicine, Pathology, Neurology, and Neurosurgery , Rhode Island Hospital and the Warren Alpert Medical School of Brown University , Providence , Rhode Island 02903 , United States
| | - Ken Ogasawara
- Biomedical and Pharmaceutical Sciences, College of Pharmacy , University of Rhode Island , Kingston , Rhode Island 02881 , United States
| | - Sravani Adusumalli
- Biomedical and Pharmaceutical Sciences, College of Pharmacy , University of Rhode Island , Kingston , Rhode Island 02881 , United States
| | - Benjamin B Barlock
- Biomedical and Pharmaceutical Sciences, College of Pharmacy , University of Rhode Island , Kingston , Rhode Island 02881 , United States
| | - Fatemeh Akhlaghi
- Biomedical and Pharmaceutical Sciences, College of Pharmacy , University of Rhode Island , Kingston , Rhode Island 02881 , United States
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Šrejber M, Navrátilová V, Paloncýová M, Bazgier V, Berka K, Anzenbacher P, Otyepka M. Membrane-attached mammalian cytochromes P450: An overview of the membrane's effects on structure, drug binding, and interactions with redox partners. J Inorg Biochem 2018; 183:117-136. [DOI: 10.1016/j.jinorgbio.2018.03.002] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 02/16/2018] [Accepted: 03/01/2018] [Indexed: 01/08/2023]
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10
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Gonzalez E, Guengerich FP. Kinetic processivity of the two-step oxidations of progesterone and pregnenolone to androgens by human cytochrome P450 17A1. J Biol Chem 2017; 292:13168-13185. [PMID: 28684414 DOI: 10.1074/jbc.m117.794917] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 06/24/2017] [Indexed: 11/06/2022] Open
Abstract
Cytochrome P450 (P450, CYP) 17A1 plays a critical role in steroid metabolism, catalyzing both the 17α-hydroxylation of pregnenolone and progesterone and the subsequent 17α,20-lyase reactions to form dehydroepiandrosterone (DHEA) and androstenedione (Andro), respectively, critical for generating glucocorticoids and androgens. Human P450 17A1 reaction rates examined are enhanced by the accessory protein cytochrome b5 (b5), but the exact role of b5 in P450 17A1-catalyzed reactions is unclear as are several details of these reactions. Here, we examined in detail the processivity of the 17α-hydroxylation and lyase steps. b5 did not enhance reaction rates by decreasing the koff rates of any of the steroids. Steroid binding to P450 17A1 was more complex than a simple two-state system. Pre-steady-state experiments indicated lag phases for Andro production from progesterone and for DHEA from pregnenolone, indicating a distributive character of the enzyme. However, we observed processivity in pregnenolone/DHEA pulse-chase experiments. (S)-Orteronel was three times more inhibitory toward the conversion of 17α-hydroxypregnenolone to DHEA than toward the 17α-hydroxylation of pregnenolone. IC50 values for (S)-orteronel were identical for blocking DHEA formation from pregnenolone and for 17α-hydroxylation, suggestive of processivity. Global kinetic modeling helped assign sets of rate constants for individual or groups of reactions, indicating that human P450 17A1 is an inherently distributive enzyme but that some processivity is present, i.e. some of the 17α-OH pregnenolone formed from pregnenolone did not dissociate from P450 17A1 before conversion to DHEA. Our results also suggest multiple conformations of P450 17A1, as previously proposed on the basis of NMR spectroscopy and X-ray crystallography.
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Affiliation(s)
- Eric Gonzalez
- From the Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146
| | - F Peter Guengerich
- From the Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146
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Vimercati S, Büchi M, Zielinski J, Peduto N, Mevissen M. Testosterone metabolism of equine single CYPs of the 3A subfamily compared to the human CYP3A4. Toxicol In Vitro 2017; 41:83-91. [DOI: 10.1016/j.tiv.2017.02.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 02/06/2017] [Accepted: 02/20/2017] [Indexed: 01/02/2023]
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12
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Pan X, Kent R, Won KJ, Jeong H. Cholic Acid Feeding Leads to Increased CYP2D6 Expression in CYP2D6-Humanized Mice. Drug Metab Dispos 2017; 45:346-352. [PMID: 28153841 DOI: 10.1124/dmd.116.074013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 01/25/2017] [Indexed: 12/17/2022] Open
Abstract
Cytochrome P450 2D6 (CYP2D6) is a major drug-metabolizing enzyme, but the factors governing transcriptional regulation of its expression remain poorly understood. Based on previous reports of small heterodimer partner (SHP) playing an important role as a transcriptional repressor of CYP2D6 expression, here we investigated how a known upstream regulator of SHP expression, namely cholestasis triggered by cholic acid (CA) feeding in mice, can lead to altered CYP2D6 expression. To this end, CYP2D6-humanized (Tg-CYP2D6) mice were fed with a CA-supplemented or control diet for 14 days, and hepatic expression of multiple genes was examined. Unexpectedly, CA feeding led to insignificant changes in SHP mRNA but also to significant (2.8-fold) decreases in SHP protein levels. In silico analysis of the SHP gene regulatory region revealed a putative binding site for a microRNA, miR-142-3p. Results from luciferase reporter assays suggest that miR-142-3p targets the SHP gene. Hepatic expression of miR-142-3p was significantly increased in CA-fed mice (∼5-fold), suggesting a potential role of miR-142-3p in the regulation of SHP expression in cholestasis. The decreased SHP protein levels were accompanied by increased expression and activity of CYP2D6 in the liver of CA-fed mice. These results suggest potential roles of differential hepatic levels of bile acids in the transcriptional regulation of CYP2D6 expression.
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Affiliation(s)
- Xian Pan
- Department of Pharmacy Practice (K.-J.W., H.J.) and Department of Biopharmaceutical Sciences (X.P., R.K., H.J.), College of Pharmacy, University of Illinois at Chicago, Chicago, Illinois
| | - Rebecca Kent
- Department of Pharmacy Practice (K.-J.W., H.J.) and Department of Biopharmaceutical Sciences (X.P., R.K., H.J.), College of Pharmacy, University of Illinois at Chicago, Chicago, Illinois
| | - Kyoung-Jae Won
- Department of Pharmacy Practice (K.-J.W., H.J.) and Department of Biopharmaceutical Sciences (X.P., R.K., H.J.), College of Pharmacy, University of Illinois at Chicago, Chicago, Illinois
| | - Hyunyoung Jeong
- Department of Pharmacy Practice (K.-J.W., H.J.) and Department of Biopharmaceutical Sciences (X.P., R.K., H.J.), College of Pharmacy, University of Illinois at Chicago, Chicago, Illinois
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Zhang LL, Zhang Y, Ren JN, Liu YL, Li JJ, Tai YN, Yang SZ, Pan SY, Fan G. Proteins differentially expressed during limonene biotransformation by Penicillium digitatum DSM 62840 were examined using iTRAQ labeling coupled with 2D-LC–MS/MS. ACTA ACUST UNITED AC 2016; 43:1481-95. [DOI: 10.1007/s10295-016-1826-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 08/08/2016] [Indexed: 01/03/2023]
Abstract
Abstract
This study focused on the differences in protein expression at various periods during limonene biotransformation by Penicillium digitatum DSM 62840. A total of 3644 protein-species were quantified by iTRAQ during limonene biotransformation (0 and 12 h). A total of 643 proteins were differentially expressed, 316 proteins were significantly up-regulated and 327 proteins were markedly down-regulated. GO, COG, and pathway enrichment analysis showed that the differentially expressed proteins possessed catalytic and binding functions and were involved in a variety of cellular and metabolic process. Furthermore, the enzymes involved in limonene transformation might be related to cytochrome P-450. This study provided a powerful platform for further exploration of biotransformation, and the identified proteins provided insight into the mechanism of limonene transformation.
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Affiliation(s)
- Lu-Lu Zhang
- grid.35155.37 0000000417904137 Key Laboratory of Environment Correlative Dietology, Ministry of Education, College of Food Science and Technology Huazhong Agricultural University 430070 Wuhan China
| | - Yan Zhang
- grid.35155.37 0000000417904137 Key Laboratory of Environment Correlative Dietology, Ministry of Education, College of Food Science and Technology Huazhong Agricultural University 430070 Wuhan China
| | - Jing-Nan Ren
- grid.35155.37 0000000417904137 Key Laboratory of Environment Correlative Dietology, Ministry of Education, College of Food Science and Technology Huazhong Agricultural University 430070 Wuhan China
| | - Yan-Long Liu
- grid.35155.37 0000000417904137 Key Laboratory of Environment Correlative Dietology, Ministry of Education, College of Food Science and Technology Huazhong Agricultural University 430070 Wuhan China
| | - Jia-Jia Li
- grid.35155.37 0000000417904137 Key Laboratory of Environment Correlative Dietology, Ministry of Education, College of Food Science and Technology Huazhong Agricultural University 430070 Wuhan China
| | - Ya-Nan Tai
- grid.35155.37 0000000417904137 Key Laboratory of Environment Correlative Dietology, Ministry of Education, College of Food Science and Technology Huazhong Agricultural University 430070 Wuhan China
| | - Shu-Zhen Yang
- grid.35155.37 0000000417904137 Key Laboratory of Environment Correlative Dietology, Ministry of Education, College of Food Science and Technology Huazhong Agricultural University 430070 Wuhan China
| | - Si-Yi Pan
- grid.35155.37 0000000417904137 Key Laboratory of Environment Correlative Dietology, Ministry of Education, College of Food Science and Technology Huazhong Agricultural University 430070 Wuhan China
| | - Gang Fan
- grid.35155.37 0000000417904137 Key Laboratory of Environment Correlative Dietology, Ministry of Education, College of Food Science and Technology Huazhong Agricultural University 430070 Wuhan China
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Gómez-Lechón MJ, Tolosa L, Donato MT. Upgrading HepG2 cells with adenoviral vectors that encode drug-metabolizing enzymes: application for drug hepatotoxicity testing. Expert Opin Drug Metab Toxicol 2016; 13:137-148. [PMID: 27671376 DOI: 10.1080/17425255.2017.1238459] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
INTRODUCTION Drug attrition rates due to hepatotoxicity are an important safety issue considered in drug development. The HepG2 hepatoma cell line is currently being used for drug-induced hepatotoxicity evaluations, but its expression of drug-metabolizing enzymes is poor compared with hepatocytes. Different approaches have been proposed to upgrade HepG2 cells for more reliable drug-induced liver injury predictions. Areas covered: We describe the advantages and limitations of HepG2 cells transduced with adenoviral vectors that encode drug-metabolizing enzymes for safety risk assessments of bioactivable compounds. Adenoviral transduction facilitates efficient and controlled delivery of multiple drug-metabolizing activities to HepG2 cells at comparable levels to primary human hepatocytes by generating an 'artificial hepatocyte'. Furthermore, adenoviral transduction enables the design of tailored cells expressing particular metabolic capacities. Expert opinion: Upgraded HepG2 cells that recreate known inter-individual variations in hepatic CYP and conjugating activities due to both genetic (e.g., polymorphisms) or environmental (e.g., induction, inhibition) factors seems a suitable model to identify bioactivable drug and conduct hepatotoxicity risk assessments. This strategy should enable the generation of customized cells by reproducing human pheno- and genotypic CYP variability to represent a valuable human hepatic cell model to develop new safer drugs and to improve existing predictive toxicity assays.
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Affiliation(s)
- M José Gómez-Lechón
- a Unidad de Hepatología Experimental , Instituto de Investigación Sanitaria La Fe (IIS La Fe) , Valencia , Spain.,b CIBEREHD, FIS , Spain
| | - Laia Tolosa
- a Unidad de Hepatología Experimental , Instituto de Investigación Sanitaria La Fe (IIS La Fe) , Valencia , Spain
| | - M Teresa Donato
- a Unidad de Hepatología Experimental , Instituto de Investigación Sanitaria La Fe (IIS La Fe) , Valencia , Spain.,b CIBEREHD, FIS , Spain.,c Departamento de Bioquímica y Biología Molecular, Facultad de Medicina , Universidad de Valencia , Valencia , Spain
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15
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Zhang HF, Li ZH, Liu JY, Liu TT, Wang P, Fang Y, Zhou J, Cui MZ, Gao N, Tian X, Gao J, Wen Q, Jia LJ, Qiao HL. Correlation of Cytochrome P450 Oxidoreductase Expression with the Expression of 10 Isoforms of Cytochrome P450 in Human Liver. ACTA ACUST UNITED AC 2016; 44:1193-200. [PMID: 27271371 PMCID: PMC4986620 DOI: 10.1124/dmd.116.069849] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 05/27/2016] [Indexed: 12/13/2022]
Abstract
Human cytochrome P450 oxidoreductase (POR) provides electrons for all microsomal cytochromes P450 (P450s) and plays an indispensable role in drug metabolism catalyzed by this family of enzymes. We evaluated 100 human liver samples and found that POR protein content varied 12.8-fold, from 12.59 to 160.97 pmol/mg, with a median value of 67.99 pmol/mg; POR mRNA expression varied by 26.4-fold. POR activity was less variable with a median value of 56.05 nmol/min per milligram. Cigarette smoking and alcohol consumption clearly influenced POR activity. Liver samples with a 2286822 TT genotype had significantly higher POR mRNA expression than samples with CT genotype. Homozygous carriers of POR2286822C>T, 2286823G>A, and 3823884A>C had significantly lower POR protein levels compared with the corresponding heterozygous carriers. Liver samples from individuals homozygous at 286823G>A, 1135612A>G, and 10954732G>A generally had lower POR activity levels than those from heterozygous or wild-type samples, whereas the common variant POR*28 significantly increased POR activity. There was a strong association between POR and the expression of P450 isoforms at the mRNA and protein level, whereas the relationship at the activity level, as well as the effect of POR protein content on P450 activity, was less pronounced. POR transcription was strongly correlated with both hepatocyte nuclear factor 4 alpha and pregnane X receptor mRNA levels. In conclusion, we have elucidated some potentially important correlations between POR single-nucleotide polymorphisms and POR expression in the Chinese population and have developed a database that correlates POR expression with the expression and activity of 10 P450s important in drug metabolism.
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Affiliation(s)
- Hai-Feng Zhang
- Institute of Clinical Pharmacology, Zhengzhou University, Zhengzhou, People's Republic of China
| | - Zhi-Hui Li
- Institute of Clinical Pharmacology, Zhengzhou University, Zhengzhou, People's Republic of China
| | - Jia-Yu Liu
- Institute of Clinical Pharmacology, Zhengzhou University, Zhengzhou, People's Republic of China
| | - Ting-Ting Liu
- Institute of Clinical Pharmacology, Zhengzhou University, Zhengzhou, People's Republic of China
| | - Ping Wang
- Institute of Clinical Pharmacology, Zhengzhou University, Zhengzhou, People's Republic of China
| | - Yan Fang
- Institute of Clinical Pharmacology, Zhengzhou University, Zhengzhou, People's Republic of China
| | - Jun Zhou
- Institute of Clinical Pharmacology, Zhengzhou University, Zhengzhou, People's Republic of China
| | - Ming-Zhu Cui
- Institute of Clinical Pharmacology, Zhengzhou University, Zhengzhou, People's Republic of China
| | - Na Gao
- Institute of Clinical Pharmacology, Zhengzhou University, Zhengzhou, People's Republic of China
| | - Xin Tian
- Institute of Clinical Pharmacology, Zhengzhou University, Zhengzhou, People's Republic of China
| | - Jie Gao
- Institute of Clinical Pharmacology, Zhengzhou University, Zhengzhou, People's Republic of China
| | - Qiang Wen
- Institute of Clinical Pharmacology, Zhengzhou University, Zhengzhou, People's Republic of China
| | - Lin-Jing Jia
- Institute of Clinical Pharmacology, Zhengzhou University, Zhengzhou, People's Republic of China
| | - Hai-Ling Qiao
- Institute of Clinical Pharmacology, Zhengzhou University, Zhengzhou, People's Republic of China
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16
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Best QA, Johnson AE, Prasai B, Rouillere A, McCarley RL. Environmentally Robust Rhodamine Reporters for Probe-based Cellular Detection of the Cancer-linked Oxidoreductase hNQO1. ACS Chem Biol 2016; 11:231-40. [PMID: 26555574 DOI: 10.1021/acschembio.5b00792] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
We successfully synthesized a fluorescent probe capable of detecting the cancer-associated NAD(P)H quinoneoxidoreductase isozyme-1 within human cells, based on results from an investigation of the stability of various rhodamines and seminaphthorhodamines toward the biological reductant NADH, present at ∼100-200 μM within cells. While rhodamines are generally known for their chemical stability, we observe that NADH causes significant and sometimes rapid modification of numerous rhodamine analogues, including those oftentimes used in imaging applications. Results from mechanistic studies lead us to rule out a radical-based reduction pathway, suggesting rhodamine reduction by NADH proceeds by a hydride transfer process to yield the reduced leuco form of the rhodamine and oxidized NAD(+). A relationship between the structural features of the rhodamines and their reactivity with NADH is observed. Rhodamines with increased alkylation on the N3- and N6-nitrogens, as well as the xanthene core, react the least with NADH; whereas, nonalkylated variants or analogues with electron-withdrawing substituents have the fastest rates of reaction. These outcomes allowed us to judiciously construct a seminaphthorhodamine-based, turn-on fluorescent probe that is capable of selectively detecting the cancer-associated, NADH-dependent enzyme NAD(P)H quinoneoxidoreductase isozyme-1 in human cancer cells, without the issue of NADH-induced deactivation of the seminaphthorhodamine reporter.
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Affiliation(s)
- Quinn A. Best
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803-1804, United States
| | - Amanda E. Johnson
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803-1804, United States
| | - Bijeta Prasai
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803-1804, United States
| | - Alexandra Rouillere
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803-1804, United States
| | - Robin L. McCarley
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803-1804, United States
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17
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Upreti VV, Wahlstrom JL. Meta-analysis of hepatic cytochrome P450 ontogeny to underwrite the prediction of pediatric pharmacokinetics using physiologically based pharmacokinetic modeling. J Clin Pharmacol 2015; 56:266-83. [DOI: 10.1002/jcph.585] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 06/29/2015] [Indexed: 11/11/2022]
Affiliation(s)
- Vijay V. Upreti
- Clinical Pharmacology, Modeling and Simulation; Amgen, Inc.; South San Francisco CA USA
| | - Jan L. Wahlstrom
- Pharmacokinetics and Drug Metabolism; Amgen, Inc.; Thousand Oaks CA USA
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18
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Derbyshire MC, Michaelson L, Parker J, Kelly S, Thacker U, Powers SJ, Bailey A, Hammond-Kosack K, Courbot M, Rudd J. Analysis of cytochrome b(5) reductase-mediated metabolism in the phytopathogenic fungus Zymoseptoria tritici reveals novel functionalities implicated in virulence. Fungal Genet Biol 2015; 82:69-84. [PMID: 26074495 PMCID: PMC4557397 DOI: 10.1016/j.fgb.2015.05.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Revised: 05/19/2015] [Accepted: 05/20/2015] [Indexed: 12/15/2022]
Abstract
Septoria tritici blotch (STB) caused by the Ascomycete fungus Zymoseptoria tritici is one of the most economically damaging diseases of wheat worldwide. Z. tritici is currently a major target for agricultural fungicides, especially in temperate regions where it is most prevalent. Many fungicides target electron transfer enzymes because these are often important for cell function. Therefore characterisation of genes encoding such enzymes may be important for the development of novel disease intervention strategies. Microsomal cytochrome b5 reductases (CBRs) are an important family of electron transfer proteins which in eukaryotes are involved in the biosynthesis of fatty acids and complex lipids including sphingolipids and sterols. Unlike the model yeast Saccharomyces cerevisiae which possesses only one microsomal CBR, the fully sequenced genome of Z. tritici bears three possible microsomal CBRs. RNA sequencing analysis revealed that ZtCBR1 is the most highly expressed of these genes under all in vitro and in planta conditions tested, therefore ΔZtCBR1 mutant strains were generated through targeted gene disruption. These strains exhibited delayed disease symptoms on wheat leaves and severely limited asexual sporulation. ΔZtCBR1 strains also exhibited aberrant spore morphology and hyphal growth in vitro. These defects coincided with alterations in fatty acid, sphingolipid and sterol biosynthesis observed through GC-MS and HPLC analyses. Data is presented which suggests that Z. tritici may use ZtCBR1 as an additional electron donor for key steps in ergosterol biosynthesis, one of which is targeted by azole fungicides. Our study reports the first functional characterisation of CBR gene family members in a plant pathogenic filamentous fungus. This also represents the first direct observation of CBR functional ablation impacting upon fungal sterol biosynthesis.
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Affiliation(s)
- Mark C Derbyshire
- Department of Plant Biology and Crop Science, Rothamsted Research, West Common, Harpenden, Hertfordshire AL5 2JQ, UK.
| | - Louise Michaelson
- Department of Biological Chemistry and Crop Protection, Rothamsted Research, West Common, Harpenden, Hertfordshire AL5 2JQ, UK
| | - Josie Parker
- Centre for Cytochrome P450 Diversity, Institute of Life Science, College of Medicine, Swansea University Singleton Park, Swansea SA2 8PP, Wales, UK
| | - Steven Kelly
- Centre for Cytochrome P450 Diversity, Institute of Life Science, College of Medicine, Swansea University Singleton Park, Swansea SA2 8PP, Wales, UK
| | | | - Stephen J Powers
- Department of Computational and Systems Biology, Rothamsted Research, West Common, Harpenden, Hertfordshire AL5 2JQ, UK
| | - Andy Bailey
- Bristol University, Senate House, Tyndall Avenue, Bristol BS8 1TH, UK
| | - Kim Hammond-Kosack
- Department of Plant Biology and Crop Science, Rothamsted Research, West Common, Harpenden, Hertfordshire AL5 2JQ, UK
| | - Mikael Courbot
- Syngenta, Syngenta AG, Schaffhauserstrasse, CH-4332 Stein, Switzerland
| | - Jason Rudd
- Department of Plant Biology and Crop Science, Rothamsted Research, West Common, Harpenden, Hertfordshire AL5 2JQ, UK.
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19
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Toselli F, de Waziers I, Dutheil M, Vincent M, Wilce PA, Dodd PR, Beaune P, Loriot MA, Gillam EMJ. Gene expression profiling of cytochromes P450, ABC transporters and their principal transcription factors in the amygdala and prefrontal cortex of alcoholics, smokers and drug-free controls by qRT-PCR. Xenobiotica 2015; 45:1129-37. [DOI: 10.3109/00498254.2015.1040102] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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20
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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: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar 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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21
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Zhang C. Involvement of Iron-Containing Proteins in Genome Integrity in Arabidopsis Thaliana. Genome Integr 2015; 6:2. [PMID: 27330736 PMCID: PMC4911903 DOI: 10.4103/2041-9414.155953] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Accepted: 03/12/2015] [Indexed: 01/03/2023] Open
Abstract
The Arabidopsis genome encodes numerous iron-containing proteins such as iron-sulfur (Fe-S) cluster proteins and hemoproteins. These proteins generally utilize iron as a cofactor, and they perform critical roles in photosynthesis, genome stability, electron transfer, and oxidation-reduction reactions. Plants have evolved sophisticated mechanisms to maintain iron homeostasis for the assembly of functional iron-containing proteins, thereby ensuring genome stability, cell development, and plant growth. Over the past few years, our understanding of iron-containing proteins and their functions involved in genome stability has expanded enormously. In this review, I provide the current perspectives on iron homeostasis in Arabidopsis, followed by a summary of iron-containing protein functions involved in genome stability maintenance and a discussion of their possible molecular mechanisms.
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Affiliation(s)
- Caiguo Zhang
- Department of Biochemistry and Molecular Genetics, School of Medicine, University of Colorado, Aurora, Colorado, USA
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22
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Chen X, Zhang Y. Identification and characterization of NADPH-dependent cytochrome P450 reductase gene and cytochrome b5 gene from Plutella xylostella: Possible involvement in resistance to beta-cypermethrin. Gene 2015; 558:208-14. [DOI: 10.1016/j.gene.2014.12.053] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Revised: 10/20/2014] [Accepted: 12/25/2014] [Indexed: 01/27/2023]
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23
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Role of cytochrome b5 and α-tocopherol to microsomal and mitochondrial oxidation. Bull Exp Biol Med 2014; 156:191-5. [PMID: 24319746 DOI: 10.1007/s10517-013-2308-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The existence of lipid-radical cycles in membranes as an LPO alternative has been proven. Cytochrome b5 seems to play the key role in the formation of these cycles. The functional role of lipid-radical cycles in cell metabolism, including the positive effect on microsomal and mitochondrial oxidation, is discussed.
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24
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Ramsden D, Tweedie DJ, Chan TS, Tracy TS. Altered CYP2C9 activity following modulation of CYP3A4 levels in human hepatocytes: an example of protein-protein interactions. Drug Metab Dispos 2014; 42:1940-6. [PMID: 25157098 DOI: 10.1124/dmd.114.057901] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cytochrome P450 (P450) protein-protein interactions resulting in modulation of enzyme activities have been well documented using recombinant isoforms. This interaction has been less clearly demonstrated in a more physiologic in vitro system such as human hepatocytes. As an expansion of earlier work (Subramanian et al., 2010), in which recombinant CYP2C9 activity decreased with increasing levels of CYP3A4, the current study modulated CYP3A4 content in human hepatocytes to determine the impact on CYP2C9. Modulation of CYP3A4 levels in situ was enabled by the use of a long-term human hepatocyte culture model (HepatoPac) shown to retain phenotypic hepatocyte function over a number of weeks. The extended period of culture allowed time for knockdown of CYP3A4 protein by small interfering RNA (siRNA) with subsequent recovery, as well as upregulation through induction with a recovery period. CYP3A4 gene silencing resulted in a 60% decrease in CYP3A4 activity and protein levels with a concomitant 74% increase in CYP2C9 activity, with no change in CYP2C9 mRNA levels. Upon removal of siRNA, both CYP2C9 and CYP3A4 activities returned to pre-knockdown levels. Importantly, modulation of CYP3A4 protein levels had no impact on cytochrome P450 reductase activities or levels. However, the possibility for competition for limiting reductase cannot be ruled out. Interestingly, lowering CYP3A4 levels also increased UDP-glucuronosyltransferase 2B7 activity. These studies clearly demonstrate that alterations in CYP3A4 levels can modulate CYP2C9 activity in situ and suggest that further studies are warranted to evaluate the possible clinical consequences of these findings.
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Affiliation(s)
- Diane Ramsden
- Drug Metabolism and Pharmacokinetics, Boehringer Ingelheim Pharmaceuticals, Ridgefield, Connecticut (D.R., D.J.T., T.S.C.); and Department of Pharmaceutical Sciences, University of Kentucky, Lexington, Kentucky (T.S.T.)
| | - Donald J Tweedie
- Drug Metabolism and Pharmacokinetics, Boehringer Ingelheim Pharmaceuticals, Ridgefield, Connecticut (D.R., D.J.T., T.S.C.); and Department of Pharmaceutical Sciences, University of Kentucky, Lexington, Kentucky (T.S.T.)
| | - Tom S Chan
- Drug Metabolism and Pharmacokinetics, Boehringer Ingelheim Pharmaceuticals, Ridgefield, Connecticut (D.R., D.J.T., T.S.C.); and Department of Pharmaceutical Sciences, University of Kentucky, Lexington, Kentucky (T.S.T.)
| | - Timothy S Tracy
- Drug Metabolism and Pharmacokinetics, Boehringer Ingelheim Pharmaceuticals, Ridgefield, Connecticut (D.R., D.J.T., T.S.C.); and Department of Pharmaceutical Sciences, University of Kentucky, Lexington, Kentucky (T.S.T.)
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25
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Zhang C. Essential functions of iron-requiring proteins in DNA replication, repair and cell cycle control. Protein Cell 2014; 5:750-60. [PMID: 25000876 PMCID: PMC4180463 DOI: 10.1007/s13238-014-0083-7] [Citation(s) in RCA: 180] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 05/04/2014] [Indexed: 02/06/2023] Open
Abstract
Eukaryotic cells contain numerous iron-requiring proteins such as iron-sulfur (Fe-S) cluster proteins, hemoproteins and ribonucleotide reductases (RNRs). These proteins utilize iron as a cofactor and perform key roles in DNA replication, DNA repair, metabolic catalysis, iron regulation and cell cycle progression. Disruption of iron homeostasis always impairs the functions of these iron-requiring proteins and is genetically associated with diseases characterized by DNA repair defects in mammals. Organisms have evolved multi-layered mechanisms to regulate iron balance to ensure genome stability and cell development. This review briefly provides current perspectives on iron homeostasis in yeast and mammals, and mainly summarizes the most recent understandings on iron-requiring protein functions involved in DNA stability maintenance and cell cycle control.
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Affiliation(s)
- Caiguo Zhang
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO, 80045, USA,
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26
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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] [Scholar 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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27
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Khan R, Zahid S, Wan YJY, Forster J, Karim ABA, Nawabi AM, Azhar A, Rahman MA, Ahmed N. Protein expression profiling of nuclear membrane protein reveals potential biomarker of human hepatocellular carcinoma. Clin Proteomics 2013; 10:6. [PMID: 23724895 PMCID: PMC3691657 DOI: 10.1186/1559-0275-10-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Accepted: 05/24/2013] [Indexed: 12/14/2022] Open
Abstract
Background Complex molecular events lead to development and progression of liver cirrhosis to HCC. Differentially expressed nuclear membrane associated proteins are responsible for the functional and structural alteration during the progression from cirrhosis to carcinoma. Although alterations/ post translational modifications in protein expression have been extensively quantified, complementary analysis of nuclear membrane proteome changes have been limited. Deciphering the molecular mechanism that differentiate between normal and disease state may lead to identification of biomarkers for carcinoma. Results Many proteins displayed differential expression when nuclear membrane proteome of hepatocellular carcinoma (HCC), fibrotic liver, and HepG2 cell line were assessed using 2-DE and ESI-Q-TOF MS/MS. From the down regulated set in HCC, we have identified for the first time a 15 KDa cytochrome b5A (CYB5A), ATP synthase subunit delta (ATPD) and Hemoglobin subunit beta (HBB) with 11, 5 and 22 peptide matches respectively. Furthermore, nitrosylation studies with S-nitrosocysteine followed by immunoblotting with anti SNO-cysteine demonstrated a novel and biologically relevant post translational modification of thiols of CYB5A in HCC specimens only. Immunofluorescence images demonstrated increased protein S-nitrosylation signals in the tumor cells and fibrotic region of HCC tissues. The two other nuclear membrane proteins which were only found to be nitrosylated in case of HCC were up regulated ATP synthase subunit beta (ATPB) and down regulated HBB. The decrease in expression of CYB5A in HCC suggests their possible role in disease progression. Further insight of the functional association of the identified proteins was obtained through KEGG/ REACTOME pathway analysis databases. String 8.3 interaction network shows strong interactions with proteins at high confidence score, which is helpful in characterization of functional abnormalities that may be a causative factor of liver pathology. Conclusion These findings may have broader implications for understanding the mechanism of development of carcinoma. However, large scale studies will be required for further verification of their critical role in development and progression of HCC.
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Affiliation(s)
- Rizma Khan
- Neurochemistry Research Unit Laboratory, Department of Biochemistry, University of Karachi, Karachi, Pakistan.
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28
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Zhao C, Tang T, Liu J, Feng X, Qiu L. Identification and expression analysis of NADH-cytochrome b₅ reductase gene in the cotton bollworm, Helicoverpa armigera. Gene 2012; 511:96-102. [PMID: 22986333 DOI: 10.1016/j.gene.2012.09.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Revised: 08/31/2012] [Accepted: 09/03/2012] [Indexed: 11/15/2022]
Abstract
NADH-cytochrome b(5) reductase (CBR) is one of the most important components of cytochrome P450s, which play an essential role in the detoxification of xenobiotics as well as insecticide resistance in insect pest. In the present study, two novel full-length cDNAs of CBR of the cotton bollworm, Helicoverpa armigera (Hübner) were amplified by means of reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE) techniques. The sequencing results showed that the transcripts were 1809bp and 1518bp for HaCBR1 and HaCBR2, respectively, including 969bp and 939bp of complete open reading frame (ORF), which encoded 322 and 312 amino acids respectively. The putative structure and function of HaCBR1 and HaCBR2 were preliminarily analyzed by SMART program. HaCBR1 and HaCBR2 (GenBank accession numbers: HQ638220 and HQ190046HQ638220HQ190046) showed high identities with CBRs of other species. The expression of HaCBR1 and HaCBR2 mRNA was detected by real-time quantitative polymerase chain reaction (RT-qPCR) in most developmental stages of H. armigera with the exception of eggs, as well as in tissues such as cuticle, fatbody and midgut. The expression level of the two genes was significantly induced by phenobarbital (PB). These results would contribute to the understanding of CBR function in H. armigera and provide information for further study on the interactions of different components of cytochrome P450 enzyme systems.
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Affiliation(s)
- Chunqing Zhao
- College of Science, China Agricultural University, Beijing, China
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29
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Kaspera R, Naraharisetti SB, Evangelista EA, Marciante KD, Psaty BM, Totah RA. Drug metabolism by CYP2C8.3 is determined by substrate dependent interactions with cytochrome P450 reductase and cytochrome b5. Biochem Pharmacol 2011; 82:681-91. [PMID: 21726541 DOI: 10.1016/j.bcp.2011.06.027] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Revised: 06/16/2011] [Accepted: 06/16/2011] [Indexed: 01/20/2023]
Abstract
Genetic polymorphisms in CYP2C8 can influence the metabolism of important therapeutic agents and cause interindividual variation in drug response and toxicity. The significance of the variant CYP2C8*3 has been controversial with reports of higher in vivo but lower in vitro activity compared to CYP2C8*1. In this study, the contribution of the redox partners cytochrome P450 reductase (CPR) and cytochrome b5 to the substrate dependent activity of CYP2C8.3 (R139K, K399R) was investigated in human liver microsomes (HLMs) and Escherichia coli expressed recombinant CYP2C8 proteins using amodiaquine, paclitaxel, rosiglitazone and cerivastatin as probe substrates. For recombinant CYP2C8.3, clearance values were two- to five-fold higher compared to CYP2C8.1. CYP2C8.3's higher k(cat) seems to be dominated by a higher, but substrate specific affinity, towards cytochrome b5 and CPR (K(D) and K(m,red)) which resulted in increased reaction coupling. A stronger binding affinity of ligands to CYP2C8.3, based on a two site binding model, in conjunction with a five fold increase in amplitude of heme spin change during binding of ligands and redox partners could potentially contribute to a higher k(cat). In HLMs, carriers of the CYP2C8*1/*3 genotype were as active as CYP2C8*1/*1 towards the CYP2C8 specific reaction amodiaquine N-deethylation. Large excess of cytochrome b5 compared to CYP2C8 in recombinant systems and HLMs inhibited metabolic clearance, diminishing the difference in k(cat) between the two enzymes, and may provide an explanation for the discrepancy to in vivo data. In silico studies illustrate the genetic differences between wild type and variant on the molecular level.
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Affiliation(s)
- Rüdiger Kaspera
- Department of Medicinal Chemistry, University of Washington, Seattle, WA 98195-7610, USA
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30
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Biological Membranes Are Nanostructures that Require Internal Heat and Imaginary Temperature as New, Unique Physiological Parameters Related to Biological Catalysts. Cell Biochem Biophys 2010; 59:133-46. [DOI: 10.1007/s12013-010-9134-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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31
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Pillai VC, Yesudas R, Shaik IH, Thekkumkara TJ, Bickel U, Srivenugopal KS, Mehvar R. Delivery of NADPH-cytochrome P450 reductase antisense oligos using avidin-biotin approach. Bioconjug Chem 2010; 21:203-7. [PMID: 20063878 DOI: 10.1021/bc900449b] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Although avidin-mediated intracellular delivery of oligonucleotides or proteins has been shown before, the efficacy studies are lacking. Here, we tested the effectiveness of avidin for delivery of a cytochrome P450 reductase (CPR) antisense oligo in rat liver epithelial cells. A phosphorodiamidate morpholino oligo (PMO) against CPR was biotinylated using four reagents with short, cleavable, or long linkers, followed by conjugation with avidin. The dose-inhibitory response of the unmodified PMO in the presence of a transfection reagent (Endoporter, EP) and the effectiveness of the EP-assisted and avidin-assisted delivery of biotinylated PMOs were tested by Western blot analysis. Additionally, in a preliminary study, the avidin-biotin PMO with a long linker was also tested in vivo in rats. The biotinylated oligos were at least as effective as the unmodified oligo. Whereas the avidin conjugate of biotinylated PMO with the short linker was ineffective, those with the long linkers showed significant reductions in CPR protein expression. Finally, the in vivo study showed modest, but significant, reductions in CPR activity. In conclusion, these studies show for the first time that avidin-mediated intracellular delivery of biotinylated oligos can effectively knock down target genes in vitro, depending on the length of the linker. Additionally, the avidin-biotin approach may be of potential value for in vivo gene knockdown.
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Affiliation(s)
- Venkateswaran C Pillai
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, 1300 Coulter, Amarillo, Texas 79106, USA
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Sivertsson L, Ek M, Darnell M, Edebert I, Ingelman-Sundberg M, Neve EPA. CYP3A4 Catalytic Activity Is Induced in Confluent Huh7 Hepatoma Cells. Drug Metab Dispos 2010; 38:995-1002. [DOI: 10.1124/dmd.110.032367] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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