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Robey RW, Fitzsimmons CM, Guiblet WM, Frye WJE, González Dalmasy JM, Wang L, Russell DA, Huff LM, Perciaccante AJ, Ali-Rahmani F, Lipsey CC, Wade HM, Mitchell AV, Maligireddy SS, Terrero D, Butcher D, Edmondson EF, Jenkins LM, Nikitina T, Zhurkin VB, Tiwari AK, Piscopio AD, Totah RA, Bates SE, Arda HE, Gottesman MM, Batista PJ. The Methyltransferases METTL7A and METTL7B Confer Resistance to Thiol-Based Histone Deacetylase Inhibitors. Mol Cancer Ther 2024; 23:464-477. [PMID: 38151817 DOI: 10.1158/1535-7163.mct-23-0144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 08/25/2023] [Accepted: 12/20/2023] [Indexed: 12/29/2023]
Abstract
Histone deacetylase inhibitors (HDACi) are part of a growing class of epigenetic therapies used for the treatment of cancer. Although HDACis are effective in the treatment of T-cell lymphomas, treatment of solid tumors with this class of drugs has not been successful. Overexpression of the multidrug resistance protein P-glycoprotein (P-gp), encoded by ABCB1, is known to confer resistance to the HDACi romidepsin in vitro, yet increased ABCB1 expression has not been associated with resistance in patients, suggesting that other mechanisms of resistance arise in the clinic. To identify alternative mechanisms of resistance to romidepsin, we selected MCF-7 breast cancer cells with romidepsin in the presence of the P-gp inhibitor verapamil to reduce the likelihood of P-gp-mediated resistance. The resulting cell line, MCF-7 DpVp300, does not express P-gp and was found to be selectively resistant to romidepsin but not to other HDACis such as belinostat, panobinostat, or vorinostat. RNA-sequencing analysis revealed upregulation of the mRNA coding for the putative methyltransferase, METTL7A, whose paralog, METTL7B, was previously shown to methylate thiol groups on hydrogen sulfide and captopril. As romidepsin has a thiol as the zinc-binding moiety, we hypothesized that METTL7A could inactivate romidepsin and other thiol-based HDACis via methylation of the thiol group. We demonstrate that expression of METTL7A or METTL7B confers resistance to thiol-based HDACis and that both enzymes are capable of methylating thiol-containing HDACis. We thus propose that METTL7A and METTL7B confer resistance to thiol-based HDACis by methylating and inactivating the zinc-binding thiol.
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Affiliation(s)
- Robert W Robey
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland
| | - Christina M Fitzsimmons
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland
| | - Wilfried M Guiblet
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland
| | - William J E Frye
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland
| | - José M González Dalmasy
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland
| | - Li Wang
- Laboratory of Receptor Biology and Gene Expression, Developmental Genomics Group, Center for Cancer Research, NCI, NIH, Bethesda, Maryland
| | - Drake A Russell
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington
| | - Lyn M Huff
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland
| | - Andrew J Perciaccante
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland
| | - Fatima Ali-Rahmani
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland
| | - Crystal C Lipsey
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland
| | - Heidi M Wade
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland
| | - Allison V Mitchell
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland
| | - Siddhardha S Maligireddy
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland
| | - David Terrero
- Department of Pharmacology and Experimental Therapeutics, Department of Cancer Cell and Cancer Biology, University of Toledo, Toledo, Ohio
| | - Donna Butcher
- Molecular Histopathology Laboratory, Frederick National Laboratory for Cancer Research, Frederick, Maryland
| | - Elijah F Edmondson
- Molecular Histopathology Laboratory, Frederick National Laboratory for Cancer Research, Frederick, Maryland
| | - Lisa M Jenkins
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland
| | - Tatiana Nikitina
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland
| | - Victor B Zhurkin
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland
| | - Amit K Tiwari
- Department of Pharmacology and Experimental Therapeutics, Department of Cancer Cell and Cancer Biology, University of Toledo, Toledo, Ohio
| | | | - Rheem A Totah
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington
| | - Susan E Bates
- Division of Hematology/Oncology, Department of Medicine, Columbia University Medical Center, New York, New York
- Hematology/Oncology Research Department, James J. Peters Department of Veterans Affairs Medical Center, New York, New York
| | - H Efsun Arda
- Laboratory of Receptor Biology and Gene Expression, Developmental Genomics Group, Center for Cancer Research, NCI, NIH, Bethesda, Maryland
| | - Michael M Gottesman
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland
| | - Pedro J Batista
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland
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Bercu JP, Ponting DJ, Ripp SL, Dobo KL, Totah RA, Bolleddula J. A Case to Support the Continued Use of Rifampin in Clinical Drug-Drug Interaction Studies. Clin Pharmacol Ther 2024. [PMID: 38494918 DOI: 10.1002/cpt.3256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 03/06/2024] [Indexed: 03/19/2024]
Affiliation(s)
- Joel P Bercu
- Gilead Sciences, Inc., Nonclinical Safety and Pathobiology (NSP), Foster City, California, USA
| | | | - Sharon L Ripp
- Pharmacokinetics, Dynamics & Metabolism, Pfizer Research & Development, Groton, Connecticut, USA
| | - Krista L Dobo
- Drug Safety Research and Development, Pfizer Research & Development, Groton, Connecticut, USA
| | - Rheem A Totah
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington, USA
| | - Jayaprakasam Bolleddula
- Quantitative Pharmacology, EMD Serono Research & Development Institute, Inc., Billerica, Massachusetts, USA
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Wiley AM, Yang J, Madhani R, Nath A, Totah RA. Investigating the association between CYP2J2 inhibitors and QT prolongation: a literature review. Drug Metab Rev 2024; 56:145-163. [PMID: 38478383 DOI: 10.1080/03602532.2024.2329928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 03/06/2024] [Indexed: 03/21/2024]
Abstract
Drug withdrawal post-marketing due to cardiotoxicity is a major concern for drug developers, regulatory agencies, and patients. One common mechanism of cardiotoxicity is through inhibition of cardiac ion channels, leading to prolongation of the QT interval and sometimes fatal arrythmias. Recently, oxylipin signaling compounds have been shown to bind to and alter ion channel function, and disruption in their cardiac levels may contribute to QT prolongation. Cytochrome P450 2J2 (CYP2J2) is the predominant CYP isoform expressed in cardiomyocytes, where it oxidizes arachidonic acid to cardioprotective epoxyeicosatrienoic acids (EETs). In addition to roles in vasodilation and angiogenesis, EETs bind to and activate various ion channels. CYP2J2 inhibition can lower EET levels and decrease their ability to preserve cardiac rhythm. In this review, we investigated the ability of known CYP inhibitors to cause QT prolongation using Certara's Drug Interaction Database. We discovered that among the multiple CYP isozymes, CYP2J2 inhibitors were more likely to also be QT-prolonging drugs (by approximately 2-fold). We explored potential binding interactions between these inhibitors and CYP2J2 using molecular docking and identified four amino acid residues (Phe61, Ala223, Asn231, and Leu402) predicted to interact with QT-prolonging drugs. The four residues are located near the opening of egress channel 2, highlighting the potential importance of this channel in CYP2J2 binding and inhibition. These findings suggest that if a drug inhibits CYP2J2 and interacts with one of these four residues, then it may have a higher risk of QT prolongation and more preclinical studies are warranted to assess cardiovascular safety.
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Affiliation(s)
- Alexandra M Wiley
- Department of Medicinal Chemistry, University of WA School of Pharmacy, Seattle, WA, USA
| | - Jade Yang
- Department of Medicinal Chemistry, University of WA School of Pharmacy, Seattle, WA, USA
| | - Rivcka Madhani
- Department of Medicinal Chemistry, University of WA School of Pharmacy, Seattle, WA, USA
| | - Abhinav Nath
- Department of Medicinal Chemistry, University of WA School of Pharmacy, Seattle, WA, USA
| | - Rheem A Totah
- Department of Medicinal Chemistry, University of WA School of Pharmacy, Seattle, WA, USA
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Czuba LC, Malhotra K, Enthoven L, Fay EE, Moreni SL, Mao J, Shi Y, Huang W, Totah RA, Isoherranen N, Hebert MF. CYP2D6 Activity Is Correlated with Changes in Plasma Concentrations of Taurocholic Acid during Pregnancy and Postpartum in CYP2D6 Extensive Metabolizers. Drug Metab Dispos 2023; 51:1474-1482. [PMID: 37550070 PMCID: PMC10586507 DOI: 10.1124/dmd.123.001358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 06/23/2023] [Accepted: 07/28/2023] [Indexed: 08/09/2023] Open
Abstract
Cytochrome P450 2D6 (CYP2D6) is involved in the metabolism of >20% of marketed drugs. CYP2D6 expression and activity exhibit high interindividual variability and is induced during pregnancy. The farnesoid X receptor (FXR) is a transcriptional regulator of CYP2D6 that is activated by bile acids. In pregnancy, elevated plasma bile acid concentrations are associated with maternal and fetal risks. However, modest changes in bile acid concentrations may occur during healthy pregnancy, thereby altering FXR signaling. A previous study demonstrated that hepatic tissue concentrations of bile acids positively correlated with the hepatic mRNA expression of CYP2D6. This study sought to characterize the plasma bile acid metabolome in healthy women (n = 47) during midpregnancy (25-28 weeks gestation) and ≥3 months postpartum and to determine if plasma bile acids correlate with CYP2D6 activity. It is hypothesized that during pregnancy, plasma bile acids would favor less hydrophobic bile acids (cholic acid vs. chenodeoxycholic acid) and that plasma concentrations of cholic acid and its conjugates would positively correlate with the urinary ratio of dextrorphan/dextromethorphan. At 25-28 weeks gestation, taurine-conjugated bile acids comprised 23% of the quantified serum bile acids compared with 7% ≥3 months postpartum. Taurocholic acid positively associated with the urinary ratio of dextrorphan/dextromethorphan, a biomarker of CYP2D6 activity. Collectively, these results confirm that the bile acid plasma metabolome differs between pregnancy and postpartum and provide evidence that taurocholic acid may impact CYP2D6 activity during pregnancy. SIGNIFICANCE STATEMENT: Bile acid homeostasis is altered in pregnancy, and plasma concentrations of taurocholic acid positively correlate with CYP2D6 activity. Differences between plasma and/or tissue concentrations of farnesoid X receptor ligands such as bile acids may contribute to the high interindividual variability in CYP2D6 expression and activity.
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Affiliation(s)
- Lindsay C Czuba
- Department of Pharmaceutics, School of Pharmacy (L.C.C., W.H., N.I.), Department of Pharmacy, School of Pharmacy (K.M., L.E., M.F.H.), Department of Obstetrics and Gynecology, School of Medicine (E.E.F., S.L.M., J.M., M.F.H.), and Department of Medicinal Chemistry, School of Pharmacy (Y.S., R.A.T.), University of Washington, Seattle, Washington
| | - Karan Malhotra
- Department of Pharmaceutics, School of Pharmacy (L.C.C., W.H., N.I.), Department of Pharmacy, School of Pharmacy (K.M., L.E., M.F.H.), Department of Obstetrics and Gynecology, School of Medicine (E.E.F., S.L.M., J.M., M.F.H.), and Department of Medicinal Chemistry, School of Pharmacy (Y.S., R.A.T.), University of Washington, Seattle, Washington
| | - Luke Enthoven
- Department of Pharmaceutics, School of Pharmacy (L.C.C., W.H., N.I.), Department of Pharmacy, School of Pharmacy (K.M., L.E., M.F.H.), Department of Obstetrics and Gynecology, School of Medicine (E.E.F., S.L.M., J.M., M.F.H.), and Department of Medicinal Chemistry, School of Pharmacy (Y.S., R.A.T.), University of Washington, Seattle, Washington
| | - Emily E Fay
- Department of Pharmaceutics, School of Pharmacy (L.C.C., W.H., N.I.), Department of Pharmacy, School of Pharmacy (K.M., L.E., M.F.H.), Department of Obstetrics and Gynecology, School of Medicine (E.E.F., S.L.M., J.M., M.F.H.), and Department of Medicinal Chemistry, School of Pharmacy (Y.S., R.A.T.), University of Washington, Seattle, Washington
| | - Sue L Moreni
- Department of Pharmaceutics, School of Pharmacy (L.C.C., W.H., N.I.), Department of Pharmacy, School of Pharmacy (K.M., L.E., M.F.H.), Department of Obstetrics and Gynecology, School of Medicine (E.E.F., S.L.M., J.M., M.F.H.), and Department of Medicinal Chemistry, School of Pharmacy (Y.S., R.A.T.), University of Washington, Seattle, Washington
| | - Jennie Mao
- Department of Pharmaceutics, School of Pharmacy (L.C.C., W.H., N.I.), Department of Pharmacy, School of Pharmacy (K.M., L.E., M.F.H.), Department of Obstetrics and Gynecology, School of Medicine (E.E.F., S.L.M., J.M., M.F.H.), and Department of Medicinal Chemistry, School of Pharmacy (Y.S., R.A.T.), University of Washington, Seattle, Washington
| | - Yuanyuan Shi
- Department of Pharmaceutics, School of Pharmacy (L.C.C., W.H., N.I.), Department of Pharmacy, School of Pharmacy (K.M., L.E., M.F.H.), Department of Obstetrics and Gynecology, School of Medicine (E.E.F., S.L.M., J.M., M.F.H.), and Department of Medicinal Chemistry, School of Pharmacy (Y.S., R.A.T.), University of Washington, Seattle, Washington
| | - Weize Huang
- Department of Pharmaceutics, School of Pharmacy (L.C.C., W.H., N.I.), Department of Pharmacy, School of Pharmacy (K.M., L.E., M.F.H.), Department of Obstetrics and Gynecology, School of Medicine (E.E.F., S.L.M., J.M., M.F.H.), and Department of Medicinal Chemistry, School of Pharmacy (Y.S., R.A.T.), University of Washington, Seattle, Washington
| | - Rheem A Totah
- Department of Pharmaceutics, School of Pharmacy (L.C.C., W.H., N.I.), Department of Pharmacy, School of Pharmacy (K.M., L.E., M.F.H.), Department of Obstetrics and Gynecology, School of Medicine (E.E.F., S.L.M., J.M., M.F.H.), and Department of Medicinal Chemistry, School of Pharmacy (Y.S., R.A.T.), University of Washington, Seattle, Washington
| | - Nina Isoherranen
- Department of Pharmaceutics, School of Pharmacy (L.C.C., W.H., N.I.), Department of Pharmacy, School of Pharmacy (K.M., L.E., M.F.H.), Department of Obstetrics and Gynecology, School of Medicine (E.E.F., S.L.M., J.M., M.F.H.), and Department of Medicinal Chemistry, School of Pharmacy (Y.S., R.A.T.), University of Washington, Seattle, Washington
| | - Mary F Hebert
- Department of Pharmaceutics, School of Pharmacy (L.C.C., W.H., N.I.), Department of Pharmacy, School of Pharmacy (K.M., L.E., M.F.H.), Department of Obstetrics and Gynecology, School of Medicine (E.E.F., S.L.M., J.M., M.F.H.), and Department of Medicinal Chemistry, School of Pharmacy (Y.S., R.A.T.), University of Washington, Seattle, Washington
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Fischer J, Totah RA, Burke PJ. IUPAC-Richter Prize: Call for Nominations. J Med Chem 2023; 66:13859. [PMID: 37844216 DOI: 10.1021/acs.jmedchem.3c01798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2023]
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Enthoven LF, Shi Y, Fay E, Kim A, Moreni S, Mao J, Isoherranen N, Totah RA, Hebert MF. Effects of Pregnancy on Plasma Sphingolipids Using a Metabolomic and Quantitative Analysis Approach. Metabolites 2023; 13:1026. [PMID: 37755306 PMCID: PMC10534641 DOI: 10.3390/metabo13091026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 09/15/2023] [Accepted: 09/18/2023] [Indexed: 09/28/2023] Open
Abstract
Changes in the maternal metabolome, and specifically the maternal lipidome, that occur during pregnancy are relatively unknown. The objective of this investigation was to evaluate the effects of pregnancy on sphingolipid levels using metabolomics analysis followed by confirmational, targeted quantitative analysis. We focused on three subclasses of sphingolipids: ceramides, sphingomyelins, and sphingosines. Forty-seven pregnant women aged 18 to 50 years old participated in this study. Blood samples were collected on two study days for metabolomics analysis. The pregnancy samples were collected between 25 and 28 weeks of gestation and the postpartum study day samples were collected ≥3 months postpartum. Each participant served as their own control. These samples were analyzed using a Ultra-performance liquid chromatography/mass spectroscopy/mass spectroscopy (UPLC/MS/MS) assay that yielded semi-quantitative peak area values that were used to compare sphingolipid levels between pregnancy and postpartum. Following this lipidomic analysis, quantitative LC/MS/MS targeted/confirmatory analysis was performed on the same study samples. In the metabolomic analysis, 43 sphingolipid metabolites were identified and their levels were assessed using relative peak area values. These profiled sphingolipids fell into three categories: ceramides, sphingomyelins, and sphingosines. Of the 43 analytes measured, 35 were significantly different during pregnancy (p < 0.05) (including seven ceramides, 26 sphingomyelins, and two sphingosines) and 32 were significantly higher during pregnancy compared to postpartum. Following metabolomics, a separate quantitative analysis was performed and yielded quantified concentration values for 23 different sphingolipids, four of which were also detected in the metabolomics study. Quantitative analysis supported the metabolomics results with 17 of the 23 analytes measured found to be significantly different during pregnancy including 11 ceramides, four sphingomyelins, and two sphingosines. Fourteen of these were significantly higher during pregnancy. Our data suggest an overall increase in plasma sphingolipid concentrations with possible implications in endothelial function, gestational diabetes mellitus (GDM), intrahepatic cholestasis of pregnancy, and fetal development. This study provides evidence for alterations in maternal sphingolipid metabolism during pregnancy.
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Affiliation(s)
- Luke F. Enthoven
- Department of Pharmacy, University of Washington, Seattle, WA 98195, USA
| | - Yuanyuan Shi
- Department of Medicinal Chemistry, University of Washington, Seattle, WA 98195, USA (R.A.T.)
| | - Emily Fay
- Department of Obstetrics and Gynecology, University of Washington, Seattle, WA 98195, USA
| | - Agnes Kim
- Department of Pharmacy, University of Washington, Seattle, WA 98195, USA
| | - Sue Moreni
- Department of Obstetrics and Gynecology, University of Washington, Seattle, WA 98195, USA
| | - Jennie Mao
- Department of Obstetrics and Gynecology, University of Washington, Seattle, WA 98195, USA
| | - Nina Isoherranen
- Department of Pharmaceutics, University of Washington, Seattle, WA 98195, USA;
| | - Rheem A. Totah
- Department of Medicinal Chemistry, University of Washington, Seattle, WA 98195, USA (R.A.T.)
| | - Mary F. Hebert
- Department of Pharmacy, University of Washington, Seattle, WA 98195, USA
- Department of Obstetrics and Gynecology, University of Washington, Seattle, WA 98195, USA
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Zeigler MB, Fay EE, Moreni SL, Mao J, Totah RA, Hebert MF. Plasma hydrogen sulfide, nitric oxide, and thiocyanate levels are lower during pregnancy compared to postpartum in a cohort of women from the Pacific northwest of the United States. Life Sci 2023; 322:121625. [PMID: 37001802 PMCID: PMC10133030 DOI: 10.1016/j.lfs.2023.121625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 03/21/2023] [Accepted: 03/22/2023] [Indexed: 04/03/2023]
Abstract
AIMS Pregnancy alters multiple physiological processes including angiogenesis, vasodilation, inflammation, and cellular redox, which are partially modulated by the gasotransmitters hydrogen sulfide (H2S) and nitric oxide (NO). In this study, we sought to determine how plasma levels of H2S, NO, and the H2S-related metabolites thiocyanate (SCN-), and methanethiol (CH3SH) change during pregnancy progression. MATERIALS AND METHODS Plasma was collected from 45 women at three points: 25-28 weeks gestation, 28-32 week gestation, and at ≥3 months postpartum. Plasma levels of H2S, SCN-, and CH3SH were measured following derivatization using monobromobimane followed by LC-MS/MS. Plasma NO was measured indirectly using the Griess reagent. KEY FINDINGS NO and SCN- were significantly lower in women at 25-28 weeks gestation and 28-32 weeks gestation than postpartum while plasma H2S levels were significantly lower at 28-32 weeks gestation than postpartum. No significant differences were observed in CH3SH. SIGNIFICANCE Previous reports demonstrated that the production of H2S and NO are stimulated during pregnancy, but we observed lower levels during pregnancy compared to postpartum. Previous reports on NO have been mixed, but given the related effects of H2S and NO, it is expected that their levels would be higher during pregnancy vs. postpartum. Future studies determining the mechanism for decreased H2S and NO during pregnancy will elucidate the role of these gasotransmitters during normal and pathological progression of pregnancy.
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Russell DA, Chau MK, Shi Y, Levasseur IN, Maldonato BJ, Totah RA. METTL7A (TMT1A) and METTL7B (TMT1B) are responsible for alkyl S-thiol methyl transferase activity in liver. Drug Metab Dispos 2023:dmd.123.001268. [PMID: 37137720 PMCID: PMC10353073 DOI: 10.1124/dmd.123.001268] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 04/19/2023] [Accepted: 04/27/2023] [Indexed: 05/05/2023] Open
Abstract
S-Methylation of drugs containing thiol-moieties often alters their activity and results in detoxification. Historically, scientists attributed methylation of exogenous aliphatic and phenolic thiols to a putative S-adenosyl-L-methionine dependent membrane-associated phase II enzyme known as thiol methyltransferase (TMT). TMT has a broad substrate specificity and methylates the thiol metabolite of spironolactone, mertansine, ziprasidone, captopril, and the active metabolites of the thienopyridine pro-drugs, clopidogrel, and prasugrel. Despite TMT's role in the S-methylation of clinically relevant drugs, the enzyme(s) responsible for this activity remained unknown. We recently identified methyltransferase-like protein 7B (METTL7B) as an alkyl thiol-methyltransferase. METTL7B is an endoplasmic-reticulum-associated protein with similar biochemical properties and substrate specificity to TMT. Yet, the historic TMT inhibitor, 2,3-dichloro-α-methylbenzylamine (DCMB), does not inhibit METTL7B, indicating that multiple enzymes contribute to TMT activity. Here we report that methyltransferase-like protein 7A (METTL7A), an uncharacterized member of the METTL7 family, is also a thiol-methyltransferase. METTL7A exhibits similar biochemical properties to METTL7B and TMT, including inhibition by DCMB (IC50 1.2 µM). Applying quantitative proteomics to human liver microsomes and gene modulation experiments in HepG2 and HeLa cells, we determined that TMT activity correlates closely with METTL7A and METTL7B protein levels. Furthermore, purification of a novel His-GST-tagged recombinant protein and subsequent activity experiments prove that METTL7A can selectively methylate exogenous thiol-containing substrates, including 7α-thiospironolactone, dithiothreitol, 4-chlorothiophenol, and mertansine. We conclude that the METTL7 family encodes for two enzymes, METTL7A and METTL7B, which we have renamed TMT1A and TMT1B, respectively, that are responsible for TMT activity in human liver microsomes. Significance Statement We identified METTL7A (TMT1A) and METTL7B (TMT1B) as the enzymes responsible for the microsomal alkyl thiol methyltransferase (TMT) activity. These are the first two enzymes directly associated with microsomal TMT activity. S-Methylation of commonly prescribed thiol-containing drugs alters their pharmacological activity and/or toxicity and identifying the enzymes responsible for this activity will improve our understanding of the DMPK properties of alkyl- or phenolic-thiol-containing therapeutics.
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Affiliation(s)
- Drake A Russell
- Medicinal Chemistry, University of Washington, United States
| | | | | | - Ian N Levasseur
- Medicinal Chemistry, University of Washington, United States
| | | | - Rheem A Totah
- Medicinal Chemistry, University of Washington, United States
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Enthoven LF, Shi Y, Fay EE, Moreni S, Mao J, Honeyman EM, Smith CK, Whittington D, Brockerhoff SE, Isoherranen N, Totah RA, Hebert MF. The Effects of Pregnancy on Amino Acid Levels and Nitrogen Disposition. Metabolites 2023; 13:242. [PMID: 36837861 PMCID: PMC9961409 DOI: 10.3390/metabo13020242] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/31/2023] [Accepted: 02/04/2023] [Indexed: 02/11/2023] Open
Abstract
Limited data are available on the effects of pregnancy on the maternal metabolome. Therefore, the objective of this study was to use metabolomics analysis to determine pathways impacted by pregnancy followed by targeted confirmatory analysis to provide more powerful conclusions about metabolic alterations during pregnancy. Forty-seven pregnant women, 18-50 years of age were included in this study, with each subject serving as their own control. Plasma samples were collected between 25 and 28 weeks gestation and again ≥3 months postpartum for metabolomics analysis utilizing an HILIC/UHPLC/MS/MS assay with confirmatory targeted specific concentration analysis for 10 of the significantly altered amino acids utilizing an LC/MS assay. Principle component analysis (PCA) on metabolomics data clearly separated pregnant and postpartum groups and identified outliers in a preliminary assessment. Of the 980 metabolites recorded, 706 were determined to be significantly different between pregnancy and postpartum. Pathway analysis revealed three significantly impacted pathways, arginine biosynthesis (p = 2 × 10-5 and FDR = 1 × 10-3), valine, leucine, and isoleucine metabolism (p = 2 × 10-5 and FDR = 2 × 10-3), and xanthine metabolism (p = 4 × 10-5 and FDR = 4 × 10-3). Of these we focused analysis on arginine biosynthesis and branched-chain amino acid (BCAA) metabolism due to their clinical importance and interconnected roles in amino acid metabolism. In the confirmational analysis, 7 of 10 metabolites were confirmed as significant and all 10 confirmed the direction of change of concentrations observed in the metabolomics analysis. The data support an alteration in urea nitrogen disposition and amino acid metabolism during pregnancy. These changes could also impact endogenous nitric oxide production and contribute to diseases of pregnancy. This study provides evidence for changes in both the ammonia-urea nitrogen and the BCAA metabolism taking place during pregnancy.
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Affiliation(s)
- Luke F. Enthoven
- Department of Pharmacy, University of Washington, Seattle, WA 98195, USA
| | - Yuanyuan Shi
- Department of Medicinal Chemistry, University of Washington, Seattle, WA 98195, USA
| | - Emily E. Fay
- Department of Obstetrics and Gynecology, University of Washington, Seattle, WA 98195, USA
| | - Sue Moreni
- Department of Obstetrics and Gynecology, University of Washington, Seattle, WA 98195, USA
| | - Jennie Mao
- Department of Obstetrics and Gynecology, University of Washington, Seattle, WA 98195, USA
| | - Emma M. Honeyman
- Department of Pharmacy, University of Washington, Seattle, WA 98195, USA
| | - Chase K. Smith
- Department of Pharmacy, University of Washington, Seattle, WA 98195, USA
| | - Dale Whittington
- Department of Medicinal Chemistry, University of Washington, Seattle, WA 98195, USA
| | | | - Nina Isoherranen
- Department of Pharmaceutics, University of Washington, Seattle, WA 98195, USA
| | - Rheem A. Totah
- Department of Medicinal Chemistry, University of Washington, Seattle, WA 98195, USA
| | - Mary F. Hebert
- Department of Pharmacy, University of Washington, Seattle, WA 98195, USA
- Department of Obstetrics and Gynecology, University of Washington, Seattle, WA 98195, USA
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10
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Cho C, Aliwarga T, Wiley AM, Totah RA. Cardioprotective mechanisms of cytochrome P450 derived oxylipins from ω-3 and ω-6 PUFAs. Advances in Pharmacology 2023; 97:201-227. [DOI: 10.1016/bs.apha.2023.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
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11
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Aliwarga T, Dinh JC, Heyward S, Prasad B, Gharib SA, Lemaitre RN, Sotoodehnia N, Totah RA. Cardiac Disease Alters Myocardial Tissue Levels of Epoxyeicosatrienoic Acids and Key Proteins Involved in Their Biosynthesis and Degradation. Int J Mol Sci 2022; 23:ijms232012433. [PMID: 36293289 PMCID: PMC9604309 DOI: 10.3390/ijms232012433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 10/02/2022] [Accepted: 10/11/2022] [Indexed: 11/16/2022] Open
Abstract
CYP2J2 is the main epoxygenase in the heart that is responsible for oxidizing arachidonic acid to cis-epoxyeicosatrienoic acids (EETs). Once formed, EETs can then be hydrolyzed by soluble epoxide hydrolase (sEH, encoded by EPHX2) or re-esterified back to the membrane. EETs have several cardioprotective properties and higher levels are usually associated with better cardiac outcomes/prognosis. This study investigates how cardiovascular disease (CVD) can influence total EET levels by altering protein expression and activity of enzymes involved in their biosynthesis and degradation. Diseased ventricular cardiac tissues were collected from patients receiving Left Ventricular Assist Device (LVAD) or heart transplants and compared to ventricular tissue from controls free of CVD. EETs, and enzymes involved in EETs biosynthesis and degradation, were measured using mass spectrometric assays. Terfenadine hydroxylation was used to probe CYP2J2 activity. Significantly higher cis- and trans-EET levels were observed in control cardiac tissue (n = 17) relative to diseased tissue (n = 24). Control cardiac tissue had higher CYP2J2 protein levels, which resulted in higher rate of terfenadine hydroxylation, compared to diseased cardiac tissues. In addition, levels of both NADPH-Cytochrome P450 oxidoreductase (POR) and sEH proteins were significantly higher in control versus diseased cardiac tissue. Overall, alterations in protein and activity of enzymes involved in the biosynthesis and degradation of EETs provide a mechanistic understanding for decreased EET levels in diseased tissues.
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Affiliation(s)
- Theresa Aliwarga
- Department of Medicinal Chemistry, University of Washington, Seattle, WA 98195, USA
| | | | | | - Bhagwat Prasad
- Department of Pharmaceutical Sciences, Washington State University, Spokane, WA 99202, USA
| | - Sina A. Gharib
- Computational Medicinal Core, Center for Lung Biology, Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, University of Washington, Seattle, WA 98104, USA
| | - Rozenn N. Lemaitre
- Cardiovascular Health Research Unit, Department of Medicine, University of Washington, Seattle, WA 98101, USA
| | - Nona Sotoodehnia
- Cardiovascular Health Research Unit, Department of Medicine, University of Washington, Seattle, WA 98101, USA
- Division of Cardiology, University of Washington, Seattle, WA 98101, USA
| | - Rheem A. Totah
- Department of Medicinal Chemistry, University of Washington, Seattle, WA 98195, USA
- Correspondence: ; Tel.: +1-206-543-9481
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12
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Shi Y, Dinh J, Pelletier R, Raccor B, Yusuff N, Morgan AJ, Harbeson S, Uttamsingh V, Totah RA. Selective deuteration of bupropion slows epimerization and reduces metabolism. Bioorg Med Chem Lett 2022; 76:129009. [PMID: 36174836 DOI: 10.1016/j.bmcl.2022.129009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 09/17/2022] [Accepted: 09/23/2022] [Indexed: 11/30/2022]
Abstract
Strategically replacing hydrogen with deuterium at sites of metabolism in small molecule drugs can significantly alter clearance and potentially enhance clinical safety. Bupropion is an antidepressant and smoking cessation medication with the potential to cause seizures. We hypothesized that incorporating deuterium at specific sites in bupropion may greatly reduce epimerization, potentially slow metabolism, and reduce the formation of toxic metabolites, namely hydroxybupropion which has been associated with bupropion's toxicity. Four deuterated analogues were synthesized incorporating deuterium at sites of metabolism and epimerization with the aim of altering the metabolic profile of bupropion. Spectroscopic binding and metabolism studies with bupropion and R-or S-d4 and R-or S-d10 analogs were performed with recombinant CYP2B6, human liver microsomes, and human hepatocytes. Results demonstrate that deuterated bupropion analogues exhibited 20-25% decrease in racemization and displayed a significant decrease in the formation of CYP2B6-mediated R,R - or S,S-hydroxybupropion with recombinant protein and human liver microsomes. In primary human hepatocytes, metabolism of deuterated analogs to R,R - and S,S-hydroxybupropion and threo- and erythro-hydrobupropion was significantly less than R/S-d0 bupropion. Selective deuterium substitution at metabolic soft spots in bupropion has the potential to provide a drug with a simplified pharmacokinetic profile, reduced toxicity and improved tolerability in patients.
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Affiliation(s)
- Yuanyuan Shi
- Department of Medicinal Chemistry, School of Pharmacy, University of Washington, Seattle, WA 98195, United States
| | - Jean Dinh
- Certara UK Limited, Simcyp Division, Level 2 Acero, 1 Concourse Way, Sheffield S1 2BJ, United Kingdom
| | - Robert Pelletier
- Department of Medicinal Chemistry, School of Pharmacy, University of Washington, Seattle, WA 98195, United States
| | - Brianne Raccor
- Pharmaceutical Sciences, College of Pharmacy & Health Sciences, Campbell University, Buies Creek, NC 27506, United States
| | - Naeem Yusuff
- Concert Pharmaceuticals, Inc., 65 Hayden Ave. Suite 3000N, Lexington, MA 02421, United States
| | - Adam J Morgan
- Concert Pharmaceuticals, Inc., 65 Hayden Ave. Suite 3000N, Lexington, MA 02421, United States
| | - Scott Harbeson
- Concert Pharmaceuticals, Inc., 65 Hayden Ave. Suite 3000N, Lexington, MA 02421, United States
| | - Vinita Uttamsingh
- Concert Pharmaceuticals, Inc., 65 Hayden Ave. Suite 3000N, Lexington, MA 02421, United States
| | - Rheem A Totah
- Department of Medicinal Chemistry, School of Pharmacy, University of Washington, Seattle, WA 98195, United States.
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13
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Lemaitre RN, Jensen PN, Zeigler M, Fretts AM, Umans JG, Howard BV, Sitlani CM, McKnight B, Gharib SA, King IB, Siscovick DS, Psaty BM, Sotoodehnia N, Totah RA. Plasma epoxyeicosatrienoic acids and diabetes-related cardiovascular disease: The cardiovascular health study. EBioMedicine 2022; 83:104189. [PMID: 35930887 PMCID: PMC9356248 DOI: 10.1016/j.ebiom.2022.104189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Revised: 07/07/2022] [Accepted: 07/14/2022] [Indexed: 11/04/2022] Open
Abstract
Background Epoxyeicosatrienoic acids (EETs) are metabolites of arachidonic acid that may impact atherosclerosis, and animal experimental studies suggest EETs protect cardiac function. Plasma EETs are mostly esterified to phospholipids and part of an active pool. To address the limited information about EETs and CVD in humans, we conducted a prospective study of total plasma EETs (free + esterified) and diabetes-related CVD in the Cardiovascular Health Study (CHS). Methods We measured 4 EET species and their metabolites, dihydroxyepoxyeicosatrienoic acids (DHETs), in plasma samples from 892 CHS participants with type 2 diabetes. We determined the association of EETs and DHETs with incident myocardial infarction (MI) and ischemic stroke using Cox regression. Findings During follow-up (median 7.5 years), we identified 150 MI and 134 ischemic strokes. In primary, multivariable analyses, elevated levels of each EET species were associated with non-significant lower risk of incident MI (for example, hazard ratio for 1 SD higher 14,15-EET: 0.86, 95% CI: 0.72–1.02; p=0.08). The EETs-MI associations became significant in analyses further adjusted for DHETs (hazard ratio for 1 SD higher 14,15-EET adjusted for 14,15-DHET: 0.76, 95% CI: 0.63–0.91; p=0.004). Elevated EET levels were associated with higher risk of ischemic stroke in primary but not secondary analyses. Three DHET species were associated with higher risk of ischemic stroke in all analyses. Interpretation Findings from this prospective study complement the extensive studies in animal models showing EETs protect cardiac function and provide new information in humans. Replication is needed to confirm the associations. Funding US National Institutes of Health.
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14
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Cho C, Zeigler M, Mizuno S, Morrison RS, Totah RA, Barker-Haliski M. Reductions in Hydrogen Sulfide and Changes in Mitochondrial Quality Control Proteins Are Evident in the Early Phases of the Corneally Kindled Mouse Model of Epilepsy. Int J Mol Sci 2022; 23:ijms23031434. [PMID: 35163358 PMCID: PMC8835945 DOI: 10.3390/ijms23031434] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 01/21/2022] [Accepted: 01/24/2022] [Indexed: 12/14/2022] Open
Abstract
Epilepsy is a heterogenous neurological disorder characterized by recurrent unprovoked seizures, mitochondrial stress, and neurodegeneration. Hydrogen sulfide (H2S) is a gasotransmitter that promotes mitochondrial function and biogenesis, elicits neuromodulation and neuroprotection, and may acutely suppress seizures. A major gap in knowledge remains in understanding the role of mitochondrial dysfunction and progressive changes in H2S levels following acute seizures or during epileptogenesis. We thus sought to quantify changes in H2S and its methylated metabolite (MeSH) via LC-MS/MS following acute maximal electroshock and 6 Hz 44 mA seizures in mice, as well as in the early phases of the corneally kindled mouse model of chronic seizures. Plasma H2S was acutely reduced after a maximal electroshock seizure. H2S or MeSH levels and expressions of related genes in whole brain homogenates from corneally kindled mice were not altered. However, plasma H2S levels were significantly lower during kindling, but not after established kindling. Moreover, we demonstrated a time-dependent increase in expression of mitochondrial membrane integrity-related proteins, OPA1, MFN2, Drp1, and Mff during kindling, which did not correlate with changes in gene expression. Taken together, short-term reductions in plasma H2S could be a novel biomarker for seizures. Future studies should further define the role of H2S and mitochondrial stress in epilepsy.
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Affiliation(s)
- Christi Cho
- Department of Medicinal Chemistry, University of Washington, Seattle, WA 98195, USA; (C.C.); (M.Z.); (R.A.T.)
| | - Maxwell Zeigler
- Department of Medicinal Chemistry, University of Washington, Seattle, WA 98195, USA; (C.C.); (M.Z.); (R.A.T.)
| | - Stephanie Mizuno
- Department of Pharmacy, University of Washington, Seattle, WA 98195, USA;
| | | | - Rheem A. Totah
- Department of Medicinal Chemistry, University of Washington, Seattle, WA 98195, USA; (C.C.); (M.Z.); (R.A.T.)
| | - Melissa Barker-Haliski
- Department of Pharmacy, University of Washington, Seattle, WA 98195, USA;
- Correspondence: ; Tel.: +1-206-685-1783
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15
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Kramlinger VM, Dalvie D, Heck CJ, Kalgutkar AS, O'Neill J, Su D, Teitelbaum A, Totah RA. Future of Biotransformation Science in the Pharmaceutical Industry. Drug Metab Dispos 2021; 50:258-267. [PMID: 34921097 DOI: 10.1124/dmd.121.000658] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 11/23/2021] [Indexed: 11/22/2022] Open
Abstract
Over the past decades, the number of scientists trained in departments dedicated to traditional medicinal chemistry, biotransformation and/or chemical toxicology have seemingly declined. Yet, there remains a strong demand for such specialized skills in the pharmaceutical industry, particularly within drug metabolism/pharmacokinetics (DMPK) departments. In this position paper, the members of the Biotransformation, Mechanisms, and Pathways Focus Group (BMPFG) steering committee reflect on the diverse roles and responsibilities of scientists trained in the biotransformation field in pharmaceutical companies and contract research organizations. The BMPFG is affiliated with the International Society for the Study of Xenobiotics (ISSX) and was specifically created to promote the exchange of ideas pertaining to topics of current and future interest involving the metabolism of xenobiotics (including drugs). The authors also delve into the relevant education and diverse training skills required to successfully nurture the future cohort of industry biotransformation scientists and guide them towards a rewarding career path. The ability of scientists with a background in biotransformation/organic chemistry to creatively solve complex drug metabolism problems encountered during research and development efforts on both small molecule or large molecular modalities is exemplified in five relevant case studies. Finally, the authors stress the importance and continued commitment to training the next generation of biotransformation scientists who are not only experienced in the metabolism of conventional small molecule therapeutics, but are also equipped to tackle emerging challenges associated with new drug discovery modalities including peptides, protein degraders and antibodies. Significance Statement Biotransformation and mechanistic drug metabolism scientists are critical to advancing chemical entities through discovery and development, yet the number of scientists academically trained for this role is on the decline. This position paper highlights the continuing demand for biotransformation scientists and the necessity to nurture creative ways to train them and guarantee the future growth of this field.
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Affiliation(s)
| | | | - Carley Js Heck
- Pfizer Worldwide Research and Development, United States
| | - Amit S Kalgutkar
- Pharmacokinetics, Dynamics, and Metabolism Dept., Pfizer Worldwide Research and Development, United States
| | | | - Dian Su
- Mersana Therapeutics, United States
| | - Aaron Teitelbaum
- Drug Metabolism and Pharmacokinetics, Boehringer Ingelheim Pharmaceuticals, United States
| | - Rheem A Totah
- Medicinal Chemistry, Univeristy of Washington, United States
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16
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Lemaitre RN, Jensen PN, Zeigler M, Denham J, Fretts AM, Umans JG, Howard BV, Sitlani CM, McKnight B, Gharib SA, King IB, Siscovick DS, Psaty BM, Sotoodehnia N, Totah RA. Plasma epoxyeicosatrienoic acids and dihydroxyeicosatrieonic acids, insulin, glucose and risk of diabetes: The strong heart study. EBioMedicine 2021; 66:103279. [PMID: 33752126 PMCID: PMC8010619 DOI: 10.1016/j.ebiom.2021.103279] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 02/24/2021] [Accepted: 02/25/2021] [Indexed: 12/28/2022] Open
Abstract
Background Epoxyeicosatrienoic acids (EETs) are metabolites of arachidonic acid with multiple biological functions. Rodent experiments suggest EETs play a role in insulin sensitivity and diabetes, but evidence in humans is limited. To address this knowledge gap, we conducted a case-cohort study in the Strong Heart Family Study, a prospective cohort among American Indians. Methods We measured 4 EET species and 4 species of corresponding downstream metabolites, dihydroxyeicosatrieonic acids (DHETs), in plasma samples from 1161 participants, including 310 with type 2 diabetes. We estimated the associations of total (esterified and free) EETs and DHETs with incident diabetes risk, adjusting for known risk factors. We also examined cross-sectional associations with plasma fasting insulin and glucose in the case-cohort and in 271 participants without diabetes from the older Strong Heart Study cohort, and meta-analyzed the results from the 2 cohorts. Findings We observed no significant association of total EET or DHET levels with incident diabetes. In addition, plasma EETs were not associated with plasma insulin or plasma glucose. However, higher plasma 14,15-DHET was associated with lower plasma insulin and lower plasma glucose. Interpretation In this first prospective study of EETs and diabetes, we found no evidence for a role of total plasma EETs in diabetes. The novel associations of 14,15-DHET with insulin and glucose warrant replication and exploration of possible mechanisms. Funding US National Institutes of Health
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Affiliation(s)
- Rozenn N Lemaitre
- Cardiovascular Health Research Unit, Department of Medicine, University of Washington, Seattle, WA, USA.
| | - Paul N Jensen
- Cardiovascular Health Research Unit, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Maxwell Zeigler
- Department of Medicinal Chemistry, University of Washington, Seattle, WA, USA
| | - Julie Denham
- Department of Medicinal Chemistry, University of Washington, Seattle, WA, USA
| | - Amanda M Fretts
- Cardiovascular Health Research Unit, Department of Epidemiology, University of Washington, Seattle, WA, USA
| | - Jason G Umans
- MedStar Health Research Institute, Hyattsville, MD, USA
| | - Barbara V Howard
- MedStar Health Research Institute, Hyattsville, MD, USA; Georgetown and Howard Universities Center for Translational Science, Washington DC, USA
| | - Colleen M Sitlani
- Cardiovascular Health Research Unit, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Barbara McKnight
- Department of Biostatistics, University of Washington, Seattle, WA, USA
| | - Sina A Gharib
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Irena B King
- Department of Internal Medicine, University of New Mexico, Albuquerque, NM, USA
| | | | - Bruce M Psaty
- Cardiovascular Health Research Unit, Department of Medicine, University of Washington, Seattle, WA, USA; Cardiovascular Health Research Unit, Department of Epidemiology, University of Washington, Seattle, WA, USA; Kaiser Permanente Washington Health Research Institute, Seattle, WA
| | - Nona Sotoodehnia
- Cardiovascular Health Research Unit, Department of Medicine, University of Washington, Seattle, WA, USA; Division of Cardiology, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Rheem A Totah
- Department of Medicinal Chemistry, University of Washington, Seattle, WA, USA
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17
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Maldonato BJ, Russell DA, Totah RA. Human METTL7B is an alkyl thiol methyltransferase that metabolizes hydrogen sulfide and captopril. Sci Rep 2021; 11:4857. [PMID: 33649426 PMCID: PMC7921093 DOI: 10.1038/s41598-021-84218-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 02/12/2021] [Indexed: 11/15/2022] Open
Abstract
Methylation of alkyl thiols is a biotransformation pathway designed to reduce thiol reactivity and potential toxicity, yet the gene and protein responsible for human alkyl thiol methyltransferase (TMT) activity remain unknown. Here we demonstrate with a range of experimental approaches using cell lines, in vitro systems, and recombinantly expressed enzyme, that human methyltransferase-like protein 7B (METTL7B) catalyzes the transfer of a methyl group from S-adenosyl-L-methionine (AdoMet) to hydrogen sulfide (H2S) and other exogenous thiol small molecules. METTL7B gene modulation experiments, including knockdown in HepG2 cells and overexpression in HeLa cells, directly alter the methylation of the drug captopril, a historic probe substrate for TMT activity. Furthermore, recombinantly expressed and purified wild-type METTL7B methylates several thiol compounds, including H2S, 7α-thiospironolactone, L-penicillamine, and captopril, in a time- and concentration-dependent manner. Typical for AdoMet-dependent small molecule methyltransferases, S-adenosyl-L-homocysteine (AdoHcy) inhibited METTL7B activity in a competitive fashion. Similarly, mutating a conserved aspartate residue, proposed to anchor AdoMet into the active site, to an alanine (D98A) abolished methylation activity. Endogenous thiols such as glutathione and cysteine, or classic substrates for other known small molecule S-, N-, and O-methyltransferases, were not substrates for METTL7B. Our results confirm, for the first time, that METTL7B, a gene implicated in multiple disease states including rheumatoid arthritis and breast cancer, encodes a protein that methylates small molecule alkyl thiols. Identifying the catalytic function of METTL7B will enable future pharmacological research in disease pathophysiology where altered METTL7B expression and, potentially H2S levels, can disrupt cell growth and redox state.
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Affiliation(s)
- Benjamin J Maldonato
- Department of Medicinal Chemistry, University of Washington, 1959 NE Pacific Ave, Box 357610, Seattle, WA, 98195, USA
| | - Drake A Russell
- Department of Medicinal Chemistry, University of Washington, 1959 NE Pacific Ave, Box 357610, Seattle, WA, 98195, USA
| | - Rheem A Totah
- Department of Medicinal Chemistry, University of Washington, 1959 NE Pacific Ave, Box 357610, Seattle, WA, 98195, USA.
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18
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Somani ST, Zeigler M, Fay EE, Leahy M, Bermudez B, Totah RA, Hebert MF. Changes in erythrocyte membrane epoxyeicosatrienoic, dihydroxyeicosatrienoic, and hydroxyeicosatetraenoic acids during pregnancy. Life Sci 2021; 264:118590. [PMID: 33069736 PMCID: PMC7755749 DOI: 10.1016/j.lfs.2020.118590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 09/27/2020] [Accepted: 10/07/2020] [Indexed: 10/23/2022]
Abstract
AIMS Pregnancy is associated with numerous changes in physiological and metabolic processes to ensure successful progression to full term. One such change is the alteration of arachidonic acid (AA) metabolism and formation of eicosanoids. This study explores the changes in AA metabolites formed through the cytochrome P450 mediated pathway to epoxyeicosatrienoic (EET), dihydroxyeicosatrienoic (DHET), and hydroxyeicosatetraenoic (HETE) acids which have been implicated in blood pressure regulation and inflammatory responses that are important for a healthy pregnancy. MAIN METHODS The study determines circulating levels of EETs, DHETs and HETEs extracted from erythrocyte membranes and measured by mass spectroscopy during the progression of a normal pregnancy. Blood samples, from 25 women, were collected at three time points including 25-28 weeks gestation, 28-32 weeks gestation, and the non-pregnant control at 3-4 months postpartum. KEY FINDINGS Results demonstrate that healthy pregnancy is associated with significant increases in 8,9-DHET, 11,12-DHET and 14,15-DHET and a decrease in trans 8,9-EET during 28-32 weeks gestation compared to 3-4 months postpartum. These differences are likely due to several mechanisms including an increase in soluble epoxide hydrolase activity, a decrease in glutathione conjugation, and altered cytochrome P450 enzyme expression and/or activity that occurs during pregnancy. SIGNIFICANCE Metabolism of AA through the cytochrome P450 pathway generates physiologically important eicosanoids that could play an important role in the progression of a healthy pregnancy. Establishing the changes that occur during normal pregnancy may, in the future, help in early detection of pregnancy complications including preeclampsia.
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Affiliation(s)
- Selina T Somani
- University of Washington, Department of Pharmacy, Seattle, WA, United States of America
| | - Maxwell Zeigler
- University of Washington, Department of Medicinal Chemistry, Seattle, WA, United States of America
| | - Emily E Fay
- University of Washington, Department of Obstetrics and Gynecology, Seattle, WA, United States of America
| | - Maggie Leahy
- University of Washington, Department of Pharmacy, Seattle, WA, United States of America
| | - Bethanee Bermudez
- University of Washington, Department of Pharmacy, Seattle, WA, United States of America
| | - Rheem A Totah
- University of Washington, Department of Medicinal Chemistry, Seattle, WA, United States of America
| | - Mary F Hebert
- University of Washington, Department of Pharmacy, Seattle, WA, United States of America; University of Washington, Department of Obstetrics and Gynecology, Seattle, WA, United States of America.
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19
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Abstract
The efficacy, safety, and tolerability of drugs are dependent on numerous factors that influence their disposition. A dose that is efficacious and safe for one individual may result in sub-therapeutic or toxic blood concentrations in others. A significant source of this variability in drug response is drug metabolism, where differences in presystemic and systemic biotransformation efficiency result in variable degrees of systemic exposure (e.g., AUC, Cmax, and/or Cmin) following administration of a fixed dose.Interindividual differences in drug biotransformation have been studied extensively. It is recognized that both intrinsic factors (e.g., genetics, age, sex, and disease states) and extrinsic factors (e.g., diet , chemical exposures from the environment, and the microbiome) play a significant role. For drug-metabolizing enzymes, genetic variation can result in the complete absence or enhanced expression of a functional enzyme. In addition, upregulation and downregulation of gene expression, in response to an altered cellular environment, can achieve the same range of metabolic function (phenotype), but often in a less predictable and time-dependent manner. Understanding the mechanistic basis for variability in drug disposition and response is essential if we are to move beyond the era of empirical, trial-and-error dose selection and into an age of personalized medicine that will improve outcomes in maintaining health and treating disease.
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Affiliation(s)
- Yvonne S Lin
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA.
| | - Kenneth E Thummel
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA
| | - Brice D Thompson
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA
| | - Rheem A Totah
- Department of Medicinal Chemistry, University of Washington, Seattle, WA, USA
| | - Christi W Cho
- Department of Medicinal Chemistry, University of Washington, Seattle, WA, USA
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20
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Basit A, Neradugomma NK, Wolford C, Fan PW, Murray B, Takahashi RH, Khojasteh SC, Smith BJ, Heyward S, Totah RA, Kelly EJ, Prasad B. Characterization of Differential Tissue Abundance of Major Non-CYP Enzymes in Human. Mol Pharm 2020; 17:4114-4124. [PMID: 32955894 DOI: 10.1021/acs.molpharmaceut.0c00559] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The availability of assays that predict the contribution of cytochrome P450 (CYP) metabolism allows for the design of new chemical entities (NCEs) with minimal oxidative metabolism. These NCEs are often substrates of non-CYP drug-metabolizing enzymes (DMEs), such as UDP-glucuronosyltransferases (UGTs), sulfotransferases (SULTs), carboxylesterases (CESs), and aldehyde oxidase (AO). Nearly 30% of clinically approved drugs are metabolized by non-CYP enzymes. However, knowledge about the differential hepatic versus extrahepatic abundance of non-CYP DMEs is limited. In this study, we detected and quantified the protein abundance of eighteen non-CYP DMEs (AO, CES1 and 2, ten UGTs, and five SULTs) across five different human tissues. AO was most abundantly expressed in the liver and to a lesser extent in the kidney; however, it was not detected in the intestine, heart, or lung. CESs were ubiquitously expressed with CES1 being predominant in the liver, while CES2 was enriched in the small intestine. Consistent with the literature, UGT1A4, UGT2B4, and UGT2B15 demonstrated liver-specific expression, whereas UGT1A10 expression was specific to the intestine. UGT1A1 and UGT1A3 were expressed in both the liver and intestine; UGT1A9 was expressed in the liver and kidney; and UGT2B17 levels were significantly higher in the intestine than in the liver. All five SULTs were detected in the liver and intestine, and SULT1A1 and 1A3 were detected in the lung. Kidney abundance was the most variable among the studied tissues, and overall, high interindividual variability (>15-fold) was observed for UGT2B17, CES2 (intestine), SULT1A1 (liver), UGT1A9, UGT2B7, and CES1 (kidney). These differential tissue abundance data can be integrated into physiologically based pharmacokinetic (PBPK) models for the prediction of non-CYP drug metabolism and toxicity in hepatic and extrahepatic tissues.
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Affiliation(s)
- Abdul Basit
- College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, Washington 99202, United States
| | - Naveen K Neradugomma
- Department of Pharmaceutics, University of Washington, Seattle, Washington 98195, United States
| | - Christopher Wolford
- Department of Pharmaceutics, University of Washington, Seattle, Washington 98195, United States
| | - Peter W Fan
- Department of Pharmacokinetics, Pharmacodynamics and Drug Metabolism Merck & Co., Inc., 33 Avenue Louis Pasteur, Boston, Massachusetts 02115, United States
| | - Bernard Murray
- Drug Metabolism and Pharmacokinetics Department, Gilead Sciences Inc., 324 Lakeside Drive, Foster City, California 94404, United States
| | - Ryan H Takahashi
- Department of Drug Metabolism and Pharmacokinetics, Genentech Inc., 1 DNA Way, MS 412a, South San Francisco, California 94080, United States
| | - S Cyrus Khojasteh
- Department of Drug Metabolism and Pharmacokinetics, Genentech Inc., 1 DNA Way, MS 412a, South San Francisco, California 94080, United States
| | - Bill J Smith
- Drug Metabolism and Pharmacokinetics Department, Gilead Sciences Inc., 324 Lakeside Drive, Foster City, California 94404, United States
| | - Scott Heyward
- BioIVT Inc., Baltimore, Maryland 21227, United States
| | - Rheem A Totah
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Edward J Kelly
- Department of Pharmaceutics, University of Washington, Seattle, Washington 98195, United States
| | - Bhagwat Prasad
- College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, Washington 99202, United States
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21
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Evangelista EA, Cho CW, Aliwarga T, Totah RA. Expression and Function of Eicosanoid-Producing Cytochrome P450 Enzymes in Solid Tumors. Front Pharmacol 2020; 11:828. [PMID: 32581794 PMCID: PMC7295938 DOI: 10.3389/fphar.2020.00828] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 05/20/2020] [Indexed: 12/14/2022] Open
Abstract
Oxylipins derived from the oxidation of polyunsaturated fatty acids (PUFAs) act as important paracrine and autocrine signaling molecules. A subclass of oxylipins, the eicosanoids, have a broad range of physiological outcomes in inflammation, the immune response, cardiovascular homeostasis, and cell growth regulation. Consequently, eicosanoids are implicated in the pathophysiology of various diseases, most notably cancer, where eicosanoid mediated signaling is involved in tumor development, progression, and angiogenesis. Cytochrome P450s (CYPs) are a superfamily of heme monooxygenases generally involved in the clearance of xenobiotics while a subset of isozymes oxidize PUFAs to eicosanoids. Several eicosanoid forming CYPs are overexpressed in tumors, elevating eicosanoid levels and suggesting a key function in tumorigenesis and progression of tumors in the lung, breast, prostate, and kidney. This review summarizes the current understanding of CYPs' involvement in solid tumor etiology and progression providing supporting public data for gene expression from The Cancer Genome Atlas.
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Affiliation(s)
- Eric A Evangelista
- Department of Pharmacy, School of Pharmacy, University of Washington, Seattle, WA, United States
| | - Christi W Cho
- Department of Medicinal Chemistry, School of Pharmacy, University of Washington, Seattle, WA, United States
| | - Theresa Aliwarga
- Department of Pharmaceutics, School of Pharmacy, University of Washington, Seattle, WA, United States
| | - Rheem A Totah
- Department of Medicinal Chemistry, School of Pharmacy, University of Washington, Seattle, WA, United States
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22
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Kahma H, Filppula AM, Launiainen T, Viinamäki J, Neuvonen M, Evangelista EA, Totah RA, Backman JT. Critical Differences between Enzyme Sources in Sensitivity to Detect Time-Dependent Inactivation of CYP2C8. Drug Metab Dispos 2019; 47:436-443. [PMID: 30709838 PMCID: PMC11022894 DOI: 10.1124/dmd.118.085498] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 01/24/2019] [Indexed: 12/18/2022] Open
Abstract
Clopidogrel acyl-β-d-glucuronide is a mechanism-based inhibitor of cytochrome P450 2C8 in human liver microsomes (HLMs). However, time-dependent inactivation (TDI) of CYP2C8 could not be detected in an earlier study in human recombinant CYP2C8 (Supersomes). Here, we investigate whether different enzyme sources exhibit differences in detection of CYP2C8 TDI under identical experimental conditions. Inactivation of CYP2C8 by amiodarone (100 μM), clopidogrel acyl-β-d-glucuronide (100 μM), gemfibrozil 1-O-β-glucuronide (100 μM), and phenelzine (100 μM) was investigated in HLMs and three recombinant human CYP2C8 preparations (Supersomes, Bactosomes, and EasyCYP Bactosomes) using amodiaquine N-deethylation as the marker reaction. Furthermore, the inactivation kinetics of CYP2C8 by clopidogrel glucuronide (5-250 μM) was determined in Supersomes and Bactosomes. Amiodarone caused weak TDI in all enzyme preparations tested, while the extent of inactivation by clopidogrel glucuronide, gemfibrozil glucuronide, and phenelzine varied markedly between preparations, and even different Supersome lots. Both glucuronides caused strong inactivation of CYP2C8 in HLMs, Bactosomes and in one Supersome lot (>50% inhibition), but significant inactivation could not be reliably detected in other Supersome lots or EasyCYP Bactosomes. In Bactosomes, the concentration producing half of kinact (KI) and maximal inactivation rate (kinact) of clopidogrel glucuronide (14 μM and 0.054 minute-1) were similar to those determined previously in HLMs. Phenelzine caused strong inactivation of CYP2C8 in one Supersome lot (91% inhibition) but not in HLMs or other recombinant CYP2C8 preparations. In conclusion, different enzyme sources and different lots of the same recombinant enzyme preparation are not equally sensitive to detect inactivation of CYP2C8, suggesting that recombinant CYPs should be avoided when identifying mechanism-based inhibitors.
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Affiliation(s)
- Helinä Kahma
- Individualized Drug Therapy Research Program, Faculty of Medicine, University of Helsinki, and Department of Clinical Pharmacology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland (H.K., A.M.F., T.L., J.V., M.N., J.T.B.) and Department of Medicinal Chemistry, University of Washington, Seattle, Washington (E.A.E., R.A.T.)
| | - Anne M Filppula
- Individualized Drug Therapy Research Program, Faculty of Medicine, University of Helsinki, and Department of Clinical Pharmacology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland (H.K., A.M.F., T.L., J.V., M.N., J.T.B.) and Department of Medicinal Chemistry, University of Washington, Seattle, Washington (E.A.E., R.A.T.)
| | - Terhi Launiainen
- Individualized Drug Therapy Research Program, Faculty of Medicine, University of Helsinki, and Department of Clinical Pharmacology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland (H.K., A.M.F., T.L., J.V., M.N., J.T.B.) and Department of Medicinal Chemistry, University of Washington, Seattle, Washington (E.A.E., R.A.T.)
| | - Jenni Viinamäki
- Individualized Drug Therapy Research Program, Faculty of Medicine, University of Helsinki, and Department of Clinical Pharmacology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland (H.K., A.M.F., T.L., J.V., M.N., J.T.B.) and Department of Medicinal Chemistry, University of Washington, Seattle, Washington (E.A.E., R.A.T.)
| | - Mikko Neuvonen
- Individualized Drug Therapy Research Program, Faculty of Medicine, University of Helsinki, and Department of Clinical Pharmacology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland (H.K., A.M.F., T.L., J.V., M.N., J.T.B.) and Department of Medicinal Chemistry, University of Washington, Seattle, Washington (E.A.E., R.A.T.)
| | - Eric A Evangelista
- Individualized Drug Therapy Research Program, Faculty of Medicine, University of Helsinki, and Department of Clinical Pharmacology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland (H.K., A.M.F., T.L., J.V., M.N., J.T.B.) and Department of Medicinal Chemistry, University of Washington, Seattle, Washington (E.A.E., R.A.T.)
| | - Rheem A Totah
- Individualized Drug Therapy Research Program, Faculty of Medicine, University of Helsinki, and Department of Clinical Pharmacology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland (H.K., A.M.F., T.L., J.V., M.N., J.T.B.) and Department of Medicinal Chemistry, University of Washington, Seattle, Washington (E.A.E., R.A.T.)
| | - Janne T Backman
- Individualized Drug Therapy Research Program, Faculty of Medicine, University of Helsinki, and Department of Clinical Pharmacology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland (H.K., A.M.F., T.L., J.V., M.N., J.T.B.) and Department of Medicinal Chemistry, University of Washington, Seattle, Washington (E.A.E., R.A.T.)
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23
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Zeigler M, Whittington D, Sotoodehnia N, Lemaitre RN, Totah RA. A sensitive and improved throughput UPLC-MS/MS quantitation method of total cytochrome P450 mediated arachidonic acid metabolites that can separate regio-isomers and cis/trans-EETs from human plasma. Chem Phys Lipids 2018; 216:162-170. [PMID: 30201384 DOI: 10.1016/j.chemphyslip.2018.09.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 08/21/2018] [Accepted: 09/05/2018] [Indexed: 12/19/2022]
Abstract
A method for the detection and quantification of hydroxyl and epoxy arachidonic acid (AA) metabolites in human plasma was developed using liquid-liquid extraction, phospholipid saponification followed by derivatization of the acid moiety and liquid chromatographic tandem mass spectrometric detection. Derivatization with a pyridinium analog allowed for detection in the positive ion mode, greatly improving sensitivity and the stability of the more labile AA metabolites. The entire method utilizes a 96-well plate format, increasing sample throughput, and was optimized to measure 5-, 8-, 9-, 11-, 12-, 15-, 19-, and 20- hydroxyeicosatetraenoic acid (HETE), 5,6-, 8,9-, 11,12-, and 14,15- dihydroxyeicosatrienoic acid (DHET), and the regio- and cis-/ trans- isomers of 5,6-, 8,9-, 11,12-, and 14,15-epoxyeicosatrienoic acid (EET). The method was validated for its applicability over the FA concentration range found in human plasma. Using 100 μL aliquots of pooled human plasma, EET levels, particularly 5,6-EET, were observed to be higher than previously reported, with measured concentrations of 23.6 ng/ml for 5,6-EET, 5.6 ng/mL for 5,6-trans-EET, 8.0 ng/mL for 8,9-EET, 1.9 ng/mL for 8,9-trans-EET, 8.8 ng/mL for 11,12-EET, 3.4 ng/mL for 11,12-trans-EET, 10.7 ng/mL for 14,15-EET, and 1.7 ng/mL 14,15-trans- EET. This method is suitable for large population studies to elucidate the complex interactions between the eicosanoids and various disease states and may be used for quantitation of a wide variety of fattyacids beyond eicosanoids from small volumes of human plasma.
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Affiliation(s)
- Maxwell Zeigler
- Department of Medicinal Chemistry, University of Washington, Box 357610, Seattle, WA 98195, USA.
| | - Dale Whittington
- Department of Medicinal Chemistry, University of Washington, Box 357610, Seattle, WA 98195, USA.
| | - Nona Sotoodehnia
- Cardiovascular Health Research Unit, Department of Medicine, University of Washington, 1730 Minor Ave, Suite 1360, Seattle, WA 98101, USA; Division of Cardiology, University of Washington, Box 356422, Seattle, WA 98195, USA.
| | - Rozenn N Lemaitre
- Cardiovascular Health Research Unit, Department of Medicine, University of Washington, 1730 Minor Ave, Suite 1360, Seattle, WA 98101, USA.
| | - Rheem A Totah
- Department of Medicinal Chemistry, University of Washington, Box 357610, Seattle, WA 98195, USA.
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24
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Aliwarga T, Evangelista EA, Sotoodehnia N, Lemaitre RN, Totah RA. Regulation of CYP2J2 and EET Levels in Cardiac Disease and Diabetes. Int J Mol Sci 2018; 19:E1916. [PMID: 29966295 PMCID: PMC6073148 DOI: 10.3390/ijms19071916] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Revised: 06/24/2018] [Accepted: 06/25/2018] [Indexed: 12/13/2022] Open
Abstract
Cytochrome P450 2J2 (CYP2J2) is a known arachidonic acid (AA) epoxygenase that mediates the formation of four bioactive regioisomers of cis-epoxyeicosatrienoic acids (EETs). Although its expression in the liver is low, CYP2J2 is mainly observed in extrahepatic tissues, including the small intestine, pancreas, lung, and heart. Changes in CYP2J2 levels or activity by xenobiotics, disease states, or polymorphisms are proposed to lead to various organ dysfunctions. Several studies have investigated the regulation of CYP2J2 and EET formation in various cell lines and have demonstrated that such regulation is tissue-dependent. In addition, studies linking CYP2J2 polymorphisms to the risk of developing cardiovascular disease (CVD) yielded contradictory results. This review will focus on the mechanisms of regulation of CYP2J2 by inducers, inhibitors, and oxidative stress modeling certain disease states in various cell lines and tissues. The implication of CYP2J2 expression, polymorphisms, activity and, as a result, EET levels in the pathophysiology of diabetes and CVD will also be discussed.
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Affiliation(s)
- Theresa Aliwarga
- Department of Medicinal Chemistry, University of Washington, Seattle, WA 98101, USA.
| | - Eric A Evangelista
- Department of Medicinal Chemistry, University of Washington, Seattle, WA 98101, USA.
| | - Nona Sotoodehnia
- Cardiovascular Health Research Unit, University of Washington, Seattle, WA 98195, USA.
- Department of Medicine, University of Washington, Seattle, WA 98195, USA.
- Division of Cardiology, University of Washington, Seattle, WA 98195, USA.
| | - Rozenn N Lemaitre
- Cardiovascular Health Research Unit, University of Washington, Seattle, WA 98195, USA.
| | - Rheem A Totah
- Department of Medicinal Chemistry, University of Washington, Seattle, WA 98101, USA.
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25
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Evangelista EA, Lemaitre RN, Sotoodehnia N, Gharib SA, Totah RA. CYP2J2 Expression in Adult Ventricular Myocytes Protects Against Reactive Oxygen Species Toxicity. Drug Metab Dispos 2018; 46:380-386. [PMID: 29343610 DOI: 10.1124/dmd.117.078840] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 01/11/2018] [Indexed: 01/08/2023] Open
Abstract
Cytochrome P450 2J2 isoform (CYP2J2) is a drug-metabolizing enzyme that is highly expressed in adult ventricular myocytes. It is responsible for the bioactivation of arachidonic acid (AA) into epoxyeicosatrienoic acids (EETs). EETs are biologically active signaling compounds that protect against disease progression, particularly in cardiovascular diseases. As a drug-metabolizing enzyme, CYP2J2 is susceptible to drug interactions that could lead to cardiotoxicity. CYP2J2 has been shown to be resistant to induction by canonical CYP inducers such as phenytoin and rifampin. It is, however, unknown how cellular stresses augment CYP2J2 expression. Here, we determine the effects of oxidative stress on gene expression in adult ventricular myocytes. Further, we assess the consequences of CYP2J2 inhibition and CYP2J2 silencing on cells when levels of reactive oxygen species (ROS) are elevated. Findings indicate that CYP2J2 expression increases in response to external ROS or when internal ROS levels are elevated. In addition, cell survival decreases with ROS exposure when CYP2J2 is chemically inhibited or when CYP2J2 expression is reduced using small interfering RNA. These effects are mitigated with external addition of EETs to the cells. Finally, we determined the results of external EETs on gene expression and show that only two of the four regioisomers cause an increase in HMOX1 expression. This work is the first to determine the consequence of cellular stress, specifically high ROS levels, on CYP2J2 expression in human ventricular myocytes and discusses how this enzyme may play an important role in response to cardiac oxidative stress.
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Affiliation(s)
- Eric A Evangelista
- Department of Medicinal Chemistry (E.A.E., R.A.T.), Cardiovascular Health Research Unit, Department of Medicine (R.N.L., N.S.), Division of Cardiology (N.S.), and Computational Medicinal Core, Center for Lung Biology, Division of Pulmonary and Critical Care Medicine, Department of Medicine (S.A.G.), University of Washington, Seattle, Washington
| | - Rozenn N Lemaitre
- Department of Medicinal Chemistry (E.A.E., R.A.T.), Cardiovascular Health Research Unit, Department of Medicine (R.N.L., N.S.), Division of Cardiology (N.S.), and Computational Medicinal Core, Center for Lung Biology, Division of Pulmonary and Critical Care Medicine, Department of Medicine (S.A.G.), University of Washington, Seattle, Washington
| | - Nona Sotoodehnia
- Department of Medicinal Chemistry (E.A.E., R.A.T.), Cardiovascular Health Research Unit, Department of Medicine (R.N.L., N.S.), Division of Cardiology (N.S.), and Computational Medicinal Core, Center for Lung Biology, Division of Pulmonary and Critical Care Medicine, Department of Medicine (S.A.G.), University of Washington, Seattle, Washington
| | - Sina A Gharib
- Department of Medicinal Chemistry (E.A.E., R.A.T.), Cardiovascular Health Research Unit, Department of Medicine (R.N.L., N.S.), Division of Cardiology (N.S.), and Computational Medicinal Core, Center for Lung Biology, Division of Pulmonary and Critical Care Medicine, Department of Medicine (S.A.G.), University of Washington, Seattle, Washington
| | - Rheem A Totah
- Department of Medicinal Chemistry (E.A.E., R.A.T.), Cardiovascular Health Research Unit, Department of Medicine (R.N.L., N.S.), Division of Cardiology (N.S.), and Computational Medicinal Core, Center for Lung Biology, Division of Pulmonary and Critical Care Medicine, Department of Medicine (S.A.G.), University of Washington, Seattle, Washington
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26
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McDonald MG, Ray S, Amorosi CJ, Sitko KA, Kowalski JP, Paco L, Nath A, Gallis B, Totah RA, Dunham MJ, Fowler DM, Rettie AE. Expression and Functional Characterization of Breast Cancer-Associated Cytochrome P450 4Z1 in Saccharomyces cerevisiae. Drug Metab Dispos 2017; 45:1364-1371. [PMID: 29018033 PMCID: PMC5697098 DOI: 10.1124/dmd.117.078188] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2017] [Accepted: 10/04/2017] [Indexed: 12/22/2022] Open
Abstract
CYP4Z1 is an "orphan" cytochrome P450 (P450) enzyme that has provoked interest because of its hypothesized role in breast cancer through formation of the signaling molecule 20-hydroxyeicosatetraenoic acid (20-HETE). We expressed human CYP4Z1 in Saccharomyces cerevisiae and evaluated its catalytic capabilities toward arachidonic and lauric acids (AA and LA). Specific and sensitive mass spectrometry assays enabled discrimination of the regioselectivity of hydroxylation of these two fatty acids. CYP4Z1 generated 7-, 8-, 9-, 10-, and 11-hydroxy LA, whereas the 12-hydroxy metabolite was not detected. HET0016, the prototypic CYP4 inhibitor, only weakly inhibited laurate metabolite formation (IC50 ∼15 μM). CYP4Z1 preferentially oxidized AA to the 14(S),15(R)-epoxide with high regioselectivity and stereoselectivity, a reaction that was also insensitive to HET0016, but neither 20-HETE nor 20-carboxy-AA were detectable metabolites. Docking of LA and AA into a CYP4Z1 homology model was consistent with this preference for internal fatty acid oxidation. Thus, human CYP4Z1 has an inhibitor profile and product regioselectivity distinct from most other CYP4 enzymes, consistent with CYP4Z1's lack of a covalently linked heme. These data suggest that, if CYP4Z1 modulates breast cancer progression, it does so by a mechanism other than direct production of 20-HETE.
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Affiliation(s)
- Matthew G McDonald
- Departments of Medicinal Chemistry (M.G.M., S.R., J.P.K., L.P., A.N., B.G., R.A.T., A.E.R.), Genome Sciences (K.A.S., C.J.A., M.J.D., D.M.F.), and Bioengineering (D.M.F.), University of Washington, Seattle, Washington
| | - Sutapa Ray
- Departments of Medicinal Chemistry (M.G.M., S.R., J.P.K., L.P., A.N., B.G., R.A.T., A.E.R.), Genome Sciences (K.A.S., C.J.A., M.J.D., D.M.F.), and Bioengineering (D.M.F.), University of Washington, Seattle, Washington
| | - Clara J Amorosi
- Departments of Medicinal Chemistry (M.G.M., S.R., J.P.K., L.P., A.N., B.G., R.A.T., A.E.R.), Genome Sciences (K.A.S., C.J.A., M.J.D., D.M.F.), and Bioengineering (D.M.F.), University of Washington, Seattle, Washington
| | - Katherine A Sitko
- Departments of Medicinal Chemistry (M.G.M., S.R., J.P.K., L.P., A.N., B.G., R.A.T., A.E.R.), Genome Sciences (K.A.S., C.J.A., M.J.D., D.M.F.), and Bioengineering (D.M.F.), University of Washington, Seattle, Washington
| | - John P Kowalski
- Departments of Medicinal Chemistry (M.G.M., S.R., J.P.K., L.P., A.N., B.G., R.A.T., A.E.R.), Genome Sciences (K.A.S., C.J.A., M.J.D., D.M.F.), and Bioengineering (D.M.F.), University of Washington, Seattle, Washington
| | - Lorela Paco
- Departments of Medicinal Chemistry (M.G.M., S.R., J.P.K., L.P., A.N., B.G., R.A.T., A.E.R.), Genome Sciences (K.A.S., C.J.A., M.J.D., D.M.F.), and Bioengineering (D.M.F.), University of Washington, Seattle, Washington
| | - Abhinav Nath
- Departments of Medicinal Chemistry (M.G.M., S.R., J.P.K., L.P., A.N., B.G., R.A.T., A.E.R.), Genome Sciences (K.A.S., C.J.A., M.J.D., D.M.F.), and Bioengineering (D.M.F.), University of Washington, Seattle, Washington
| | - Byron Gallis
- Departments of Medicinal Chemistry (M.G.M., S.R., J.P.K., L.P., A.N., B.G., R.A.T., A.E.R.), Genome Sciences (K.A.S., C.J.A., M.J.D., D.M.F.), and Bioengineering (D.M.F.), University of Washington, Seattle, Washington
| | - Rheem A Totah
- Departments of Medicinal Chemistry (M.G.M., S.R., J.P.K., L.P., A.N., B.G., R.A.T., A.E.R.), Genome Sciences (K.A.S., C.J.A., M.J.D., D.M.F.), and Bioengineering (D.M.F.), University of Washington, Seattle, Washington
| | - Maitreya J Dunham
- Departments of Medicinal Chemistry (M.G.M., S.R., J.P.K., L.P., A.N., B.G., R.A.T., A.E.R.), Genome Sciences (K.A.S., C.J.A., M.J.D., D.M.F.), and Bioengineering (D.M.F.), University of Washington, Seattle, Washington
| | - Douglas M Fowler
- Departments of Medicinal Chemistry (M.G.M., S.R., J.P.K., L.P., A.N., B.G., R.A.T., A.E.R.), Genome Sciences (K.A.S., C.J.A., M.J.D., D.M.F.), and Bioengineering (D.M.F.), University of Washington, Seattle, Washington
| | - Allan E Rettie
- Departments of Medicinal Chemistry (M.G.M., S.R., J.P.K., L.P., A.N., B.G., R.A.T., A.E.R.), Genome Sciences (K.A.S., C.J.A., M.J.D., D.M.F.), and Bioengineering (D.M.F.), University of Washington, Seattle, Washington
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27
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Aliwarga T, Raccor BS, Lemaitre RN, Sotoodehnia N, Gharib SA, Xu L, Totah RA. Enzymatic and free radical formation of cis- and trans- epoxyeicosatrienoic acids in vitro and in vivo. Free Radic Biol Med 2017; 112:131-140. [PMID: 28734877 PMCID: PMC5623104 DOI: 10.1016/j.freeradbiomed.2017.07.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Revised: 07/01/2017] [Accepted: 07/18/2017] [Indexed: 10/19/2022]
Abstract
Epoxyeicosatrienoic acids (EETs) are metabolites of arachidonic acid (AA) oxidation that have important cardioprotective and signaling properties. AA is an ω-6 polyunsaturated fatty acid (PUFA) that is prone to autoxidation. Although hydroperoxides and isoprostanes are major autoxidation products of AA, EETs are also formed from the largely overlooked peroxyl radical addition mechanism. While autoxidation yields both cis- and trans-EETs, cytochrome P450 (CYP) epoxygenases have been shown to exclusively catalyze the formation of all regioisomer cis-EETs, on each of the double bonds. In plasma and red blood cell (RBC) membranes, cis- and trans-EETs have been observed, and both have multiple physiological functions. We developed a sensitive ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) assay that separates cis- and trans- isomers of EETs and applied it to determine the relative distribution of cis- vs. trans-EETs in reaction mixtures of AA subjected to free radical oxidation in benzene and liposomes in vitro. We also determined the in vivo distribution of EETs in several tissues, including human and mouse heart, and RBC membranes. We then measured EET levels in heart and RBC of young mice compared to old. Formation of EETs in free radical reactions of AA in benzene and in liposomes exhibited time- and AA concentration-dependent increase and trans-EET levels were higher than cis-EETs under both conditions. In contrast, cis-EET levels were overall higher in biological samples. In general, trans-EETs increased with mouse age more than cis-EETs. We propose a mechanism for the non-enzymatic formation of cis- and trans-EETs involving addition of the peroxyl radical to one of AA's double bonds followed by bond rotation and intramolecular homolytic substitution (SHi). Enzymatic formation of cis-EETs by cytochrome P450 most likely occurs via a one-step concerted mechanism that does not allow bond rotation. The ability to accurately measure circulating EETs resulting from autoxidation or enzymatic reactions in plasma and RBC membranes will allow for future studies investigating how these important signaling lipids correlate with heart disease outcomes.
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Affiliation(s)
- Theresa Aliwarga
- Department of Medicinal Chemistry, University of Washington, Box 357610, Seattle, WA 98195, USA.
| | - Brianne S Raccor
- Department of Pharmaceutical Sciences, Campbell University, PO Box 1090, Buies Creek, NC 27506, USA.
| | - Rozenn N Lemaitre
- Cardiovascular Health Research Unit, Department of Medicine, University of Washington, 1730 Minor Ave, Suite 1360, Seattle, WA 98101, USA.
| | - Nona Sotoodehnia
- Cardiovascular Health Research Unit, Department of Medicine, University of Washington, 1730 Minor Ave, Suite 1360, Seattle, WA 98101, USA; Division of Cardiology, University of Washington, Box 356422, Seattle, WA 98195, USA.
| | - Sina A Gharib
- Computational Medicinal Core, Center for Lung Biology, Division of Pulmonary & Critical Care Medicine, Department of Medicine, University of Washington, S376- 815 Mercer, Box 385052, Seattle, WA, USA.
| | - Libin Xu
- Department of Medicinal Chemistry, University of Washington, Box 357610, Seattle, WA 98195, USA.
| | - Rheem A Totah
- Department of Medicinal Chemistry, University of Washington, Box 357610, Seattle, WA 98195, USA.
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Roberts AG, Katayama J, Kaspera R, Ledwitch KV, Le Trong I, Stenkamp RE, Thompson JA, Totah RA. The role of cytochrome P450 BM3 phenylalanine-87 and threonine-268 in binding organic hydroperoxides. Biochim Biophys Acta Gen Subj 2016; 1860:669-77. [DOI: 10.1016/j.bbagen.2015.12.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Revised: 12/09/2015] [Accepted: 12/18/2015] [Indexed: 11/28/2022]
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Abstract
Cytochrome P450-dependent ω-hydroxylation is a prototypic metabolic reaction of CYP4 family members that is important for the elimination and bioactivation of not only therapeutic drugs, but also endogenous compounds, principally fatty acids. Eicosanoids, derived from arachidonic acid, are key substrates in the latter category. Human CYP4 enzymes, mainly CYP4A11, CYP4F2, and CYP4F3B, hydroxylate arachidonic acid at the omega position to form 20-HETE, which has important effects in tumor progression and on angiogenesis and blood pressure regulation in the vasculature and kidney. CYP4F3A in myeloid tissue catalyzes the ω-hydroxylation of leukotriene B4 to 20-hydroxy leukotriene B4, an inactivation process that is critical for the regulation of the inflammatory response. Here, we review the enzymology, tissue distribution, and substrate selectivity of human CYP4 ω-hydroxylases and their roles as catalysts for the formation and termination of the biological effects of key eicosanoid metabolites in inflammation and cancer progression.
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Affiliation(s)
- Amanda L Johnson
- Department of Medicinal Chemistry, School of Pharmacy, University of Washington, Seattle, Washington, USA
| | - Katheryne Z Edson
- Department of Medicinal Chemistry, School of Pharmacy, University of Washington, Seattle, Washington, USA; Amgen Inc., Thousand Oaks, California, USA
| | - Rheem A Totah
- Department of Medicinal Chemistry, School of Pharmacy, University of Washington, Seattle, Washington, USA
| | - Allan E Rettie
- Department of Medicinal Chemistry, School of Pharmacy, University of Washington, Seattle, Washington, USA.
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Kaspera R, Kirby BJ, Sahele T, Collier AC, Kharasch ED, Unadkat JD, Totah RA. Investigating the contribution of CYP2J2 to ritonavir metabolism in vitro and in vivo. Biochem Pharmacol 2014; 91:109-18. [PMID: 24973543 DOI: 10.1016/j.bcp.2014.06.020] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 06/17/2014] [Accepted: 06/18/2014] [Indexed: 10/25/2022]
Abstract
Ritonavir, an HIV protease inhibitor, is successfully used for the prevention and treatment of HIV infections. Ritonavir pharmacokinetics are complicated by inhibition, induction and pharmacogenetics of cytochrome P450 (CYP) enzymes mediating its clearance. This investigation revealed that CYP2J2, along with CYP3A4/5 and CYP2D6, efficiently metabolizes ritonavir, and to a CYP2J2-specific (minor) metabolite. Chemical inhibition of ritonavir metabolism, clearance, KI/kinact and abundance of CYP2J2 in liver microsomes were evaluated and then applied to an in vitro-in vivo static scaling model to estimate the contribution of each isozyme, as a function of CYP abundance, activity, and genotype. Disposition of the CYP2J2-specific metabolite was also evaluated in vivo. In plasma, metabolite abundance was well above previously reported levels with circulating concentrations measured at 2 μM for the main hydroxylisopropyl metabolite. Ritonavir and metabolite plasma profiles were simulated using Simcyp(®). A modest (2-6%) contribution of CYP2J2 to ritonavir clearance is predicted which increases to more than 20% in subjects carrying CYP2D6 poor metabolizer polymorphisms and CYP3A4 irreversible inhibition. These results indicate that minor drug metabolizing enzymes could become quantitatively important in RTV clearance if main metabolic pathways are impeded.
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Affiliation(s)
- Rüdiger Kaspera
- Department of Medicinal Chemistry, School of Pharmacy, University of Washington, Box 357610, Seattle, WA 98195-7610, USA.
| | - Brian J Kirby
- Department of Pharmaceutics, School of Pharmacy, University of Washington, Box 357630, Seattle, WA 98195-7630, USA.
| | - Tariku Sahele
- Department of Medicinal Chemistry, School of Pharmacy, University of Washington, Box 357610, Seattle, WA 98195-7610, USA.
| | - Ann C Collier
- Department of Medicine, University of Washington, Box 359929, Seattle, WA 98195-9929, USA.
| | - Evan D Kharasch
- Department of Anesthesiology, School of Medicine, Washington University, 660 South Euclid Avenue, Campus Box 8054, St. Louis, MO 63110, USA.
| | - Jashvant D Unadkat
- Department of Pharmaceutics, School of Pharmacy, University of Washington, Box 357630, Seattle, WA 98195-7630, USA.
| | - Rheem A Totah
- Department of Medicinal Chemistry, School of Pharmacy, University of Washington, Box 357610, Seattle, WA 98195-7610, USA.
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Evangelista EA, Kaspera R, Mokadam NA, Jones JP, Totah RA. Activity, inhibition, and induction of cytochrome P450 2J2 in adult human primary cardiomyocytes. Drug Metab Dispos 2013; 41:2087-94. [PMID: 24021950 DOI: 10.1124/dmd.113.053389] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Cytochrome P450 2J2 plays a significant role in the epoxidation of arachidonic acid to signaling molecules important in cardiovascular events. CYP2J2 also contributes to drug metabolism and is responsible for the intestinal clearance of ebastine. However, the interaction between arachidonic acid metabolism and drug metabolism in cardiac tissue, the main expression site of CYP2J2, has not been examined. Here we investigate an adult-derived human primary cardiac cell line as a suitable model to study metabolic drug interactions (inhibition and induction) of CYP2J2 in cardiac tissue. The primary human cardiomyocyte cell line demonstrated similar mRNA-expression profiles of P450 enzymes to adult human ventricular tissue. CYP2J2 was the dominant isozyme with minor contributions from CYP2D6 and CYP2E1. Both terfenadine and astemizole oxidation were observed in this cell line, whereas midazolam was not metabolized suggesting lack of CYP3A activity. Compared with recombinant CYP2J2, terfenadine was hydroxylated in cardiomyocytes at a similar K(m) value of 1.5 μM. The V(max) of terfenadine hydroxylation in recombinant enzyme was found to be 29.4 pmol/pmol P450 per minute and in the cells 6.0 pmol/pmol P450 per minute. CYP2J2 activity in the cell line was inhibited by danazol, astemizole, and ketoconazole in submicromolar range, but also by xenobiotics known to cause cardiac adverse effects. Of the 14 compounds tested for CYP2J2 induction, only rosiglitazone increased mRNA expression, by 1.8-fold. This cell model can be a useful in vitro model to investigate the role of CYP2J2-mediated drug metabolism, arachidonic acid metabolism, and their association to drug induced cardiotoxicity.
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Affiliation(s)
- Eric A Evangelista
- Department of Medicinal Chemistry (E.A.E., R.K., J.P.J., R.A.T.) and Division of Cardiothoracic Surgery, University of Washington, Seattle, Washington (N.A.M.)
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Raccor BS, Sun J, Lawrence RF, Li L, Zhang H, Somerman MJ, Totah RA. Quantitation of zoledronic acid in murine bone by liquid chromatography coupled with tandem mass spectrometry. J Chromatogr B Analyt Technol Biomed Life Sci 2013; 935:54-60. [PMID: 23954589 DOI: 10.1016/j.jchromb.2013.07.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2013] [Revised: 07/14/2013] [Accepted: 07/19/2013] [Indexed: 10/26/2022]
Abstract
An in vitro method for extraction and quantification of zoledronic acid (ZA) from murine bone was developed. Whole mouse bones were incubated in ZA solutions with predetermined concentrations and bound ZA was subsequently extracted from bone with phosphoric acid and derivatized using trimethylsilyl diazomethane (TMS-DAM). ZA tetra-methyl phosphonate was quantified by liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS). This resulted in a sensitive, accurate, and precise method that was linear over three orders of magnitude (0.0250-50.0μg/mL ZA). For quality control (QC) samples, intra-and inter-day coefficients of variance were calculated and were less than 10%. This method was then applied to an in vivo model to quantitate ZA from the femur and mandible of three mice treated with ZA for two weeks. The mean ZA extracted from the mandible was four fold higher than that extracted from the femur (3.06±0.52 vs. 0.76±0.09ng/mg, respectively) indicating that ZA did not distribute equally in the skeleton and had a preference to the mandible. In conclusion, a highly sensitive method to measure ZA from mouse skeleton was developed, which can be easily adapted to multiple mammalian models including humans receiving ZA treatment.
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Affiliation(s)
- Brianne S Raccor
- Department of Medicinal Chemistry, School of Pharmacy, University of Washington, Seattle, WA 98195, USA
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Floyd JS, Kaspera R, Marciante KD, Weiss NS, Heckbert SR, Lumley T, Wiggins KL, Tamraz B, Kwok PY, Totah RA, Psaty BM. A screening study of drug-drug interactions in cerivastatin users: an adverse effect of clopidogrel. Clin Pharmacol Ther 2012; 91:896-904. [PMID: 22419147 DOI: 10.1038/clpt.2011.295] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
An analysis of a case-control study of rhabdomyolysis was conducted to screen for previously unrecognized cytochrome P450 enzyme (CYP) 2C8 inhibitors that may cause other clinically important drug-drug interactions. Medication use in cases of rhabdomyolysis using cerivastatin (n = 72) was compared with that in controls using atorvastatin (n = 287) for the period 1998-2001. The use of clopidogrel was strongly associated with rhabdomyolysis (odds ratio (OR) 29.6; 95% confidence interval (CI), 6.1-143). In a replication effort that used the US Food and Drug Administration (FDA) Adverse Event Reporting System (AERS), it was found that clopidogrel was used more commonly in patients with rhabdomyolysis receiving cerivastatin (17%) than in those receiving atorvastatin (0%, OR infinity; 95% CI = 5.2-infinity). Several medications were tested in vitro for their potential to cause drug-drug interactions. Clopidogrel, rosiglitazone, and montelukast were the most potent inhibitors of cerivastatin metabolism. Clopidogrel and its metabolites also inhibited cerivastatin metabolism in human hepatocytes. These epidemiological and in vitro findings suggest that clopidogrel may cause clinically important, dose-dependent drug-drug interactions with other medications metabolized by CYP2C8.
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Affiliation(s)
- J S Floyd
- Cardiovascular Health Research Unit, University of Washington, Seattle, Washington, USA.
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Lee CA, Jones JP, Katayama J, Kaspera R, Jiang Y, Freiwald S, Smith E, Walker GS, Totah RA. Identifying a selective substrate and inhibitor pair for the evaluation of CYP2J2 activity. Drug Metab Dispos 2012; 40:943-51. [PMID: 22328583 DOI: 10.1124/dmd.111.043505] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
CYP2J2, an arachidonic acid epoxygenase, is recognized for its role in the first-pass metabolism of astemizole and ebastine. To fully assess the role of CYP2J2 in drug metabolism, a selective substrate and potent specific chemical inhibitor are essential. In this study, we report amiodarone 4-hydoxylation as a specific CYP2J2-catalyzed reaction with no CYP3A4, or other drug-metabolizing enzyme, involvement. Amiodarone 4-hydroxylation enabled the determination of liver relative activity factor and intersystem extrapolation factor for CYP2J2. Amiodarone 4-hydroxylation correlated with astemizole O-demethylation but not with CYP2J2 protein content in a sample of human liver microsomes. To identify a specific CYP2J2 inhibitor, 138 drugs were screened using terfenadine and astemizole as probe substrates with recombinant CYP2J2. Forty-two drugs inhibited CYP2J2 activity by ≥50% at 30 μM, but inhibition was substrate-dependent. Of these, danazol was a potent inhibitor of both hydroxylation of terfenadine (IC(50) = 77 nM) and O-demethylation of astemizole (K(i) = 20 nM), and inhibition was mostly competitive. Danazol inhibited CYP2C9, CYP2C8, and CYP2D6 with IC(50) values of 1.44, 1.95, and 2.74 μM, respectively. Amiodarone or astemizole were included in a seven-probe cocktail for cytochrome P450 (P450) drug-interaction screening potential, and astemizole demonstrated a better profile because it did not appreciably interact with other P450 probes. Thus, danazol, amiodarone, and astemizole will facilitate the ability to determine the metabolic role of CYP2J2 in hepatic and extrahepatic tissues.
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Affiliation(s)
- Caroline A Lee
- Department of Drug Metabolism, Pfizer Global Research, La Jolla, California, USA
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Kaspera R, Sahele T, Lakatos K, Totah RA. Cytochrome P450BM-3 reduces aldehydes to alcohols through a direct hydride transfer. Biochem Biophys Res Commun 2012; 418:464-8. [PMID: 22281497 DOI: 10.1016/j.bbrc.2012.01.040] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Accepted: 01/09/2012] [Indexed: 12/15/2022]
Abstract
Cytochrome P450BM-3 catalyzed the reduction of lipophilic aldehydes to alcohols efficiently. A k(cat) of ∼25 min(-1) was obtained for the reduction of methoxy benzaldehyde with wild type P450BM-3 protein which was higher than in the isolated reductase domain (BMR) alone and increased in specific P450-domain variants. The reduction was caused by a direct hydride transfer from preferentially R-NADP(2)H to the carbonyl moiety of the substrate. Weak substrate-P450-binding of the aldehyde, turnover with the reductase domain alone, a deuterium incorporation in the product from NADP(2)H but not D(2)O, and no inhibition by imidazole suggests the reductase domain of P450BM-3 as the potential catalytic site. However, increased aldehyde reduction by P450 domain variants (P450BM-3 F87A T268A) may involve allosteric or redox mechanistic interactions between heme and reductase domains. This is a novel reduction of aldehydes by P450BM-3 involving a direct hydride transfer and could have implications for the metabolism of endogenous substrates or xenobiotics.
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Affiliation(s)
- Rüdiger Kaspera
- Department of Medicinal Chemistry, University of Washington, Box 357610, Seattle, WA 98195-7610, USA
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Raccor BS, Claessens AJ, Dinh JC, Park JR, Hawkins DS, Thomas SS, Makar KW, McCune JS, Totah RA. Potential contribution of cytochrome P450 2B6 to hepatic 4-hydroxycyclophosphamide formation in vitro and in vivo. Drug Metab Dispos 2011; 40:54-63. [PMID: 21976622 DOI: 10.1124/dmd.111.039347] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Results from retrospective studies on the relationship between cytochrome P450 (P450) 2B6 (CYP2B6) genotype and cyclophosphamide (CY) efficacy and toxicity in adult cancer patients have been conflicting. We evaluated this relationship in children, who have faster CY clearance and receive different CY-based regimens than adults. These factors may influence the P450s metabolizing CY to 4-hydroxycyclophosphamide (4HCY), the principal precursor to CY's cytotoxic metabolite. Therefore, we sought to characterize the in vitro and in vivo roles of hepatic CYP2B6 and its main allelic variants in 4HCY formation. CYP2B6 is the major isozyme responsible for 4HCY formation in recombinant P450 Supersomes. In human liver microsomes (HLM), 4HCY formation correlated with known phenotypic markers of CYP2B6 activity, specifically formation of (S)-2-ethyl-1,5-dimethyl-3,3-diphenyl pyrrolidine and hydroxybupropion. However, in HLM, CYP3A4/5 also contributes to 4HCY formation at the CY concentrations similar to plasma concentrations achieved in children (0.1 mM). 4HCY formation was not associated with CYP2B6 genotype at low (0.1 mM) or high (1 mM) CY concentrations potentially because CYP3A4/5 and other isozymes also form 4HCY. To remove this confounder, 4HCY formation was evaluated in recombinant CYP2B6 enzymes, which demonstrated that 4HCY formation was lower for CYP2B6.4 and CYP2B6.5 compared with CYP2B6.1. In vivo, CYP2B6 genotype was not directly related to CY clearance or ratio of 4HCY/CY areas under the curve in 51 children receiving CY-based regimens. Concomitant chemotherapy agents did not influence 4HCY formation in vitro. We conclude that CYP2B6 genotype is not consistently related to 4HCY formation in vitro or in vivo.
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Affiliation(s)
- Brianne S Raccor
- Department of Pharmacy, University of Washington, Seattle, WA 98195-7610, USA
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Kaspera R, Totah RA. Epoxyeicosatrienoic acids: formation, metabolism and potential role in tissue physiology and pathophysiology. Expert Opin Drug Metab Toxicol 2010; 5:757-71. [PMID: 19505190 DOI: 10.1517/17425250902932923] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND CYP enzymes from the CYP2C and CYP2J subfamilies metabolize arachidonic acid in a regiospecific and stereoselective manner to eight epoxyeicosatrienoic acids (EETs). Various EETs have been detected in the liver, as well as in many extrahepatic tissues, and have been implicated in numerous physiological functions from cell signaling to vasodilation and angiogenesis. OBJECTIVE This report reviews the sites of expression and activity of arachidonic acid epoxygenase CYP isoforms, as well as the physiological role and metabolism of EETs in various extrahepatic tissues. Possible functions of EETs in tissue pathophysiology and implications as potential drug targets are also discussed. METHODS The most recent primary research literature on EET forming enzymes and the new physiological functions of EETs in various tissues were reviewed. RESULTS/CONCLUSIONS Epoxyeicosatrienoic acids are important in maintaining the homeostasis and in responding to stress in various extra hepatic tissues. It is not clear whether these effects are owing to EETs acting on a universal receptor or through a mechanism involving a second messenger. A better understanding of the regulation of EET levels and their mechanism of action on various receptors will accelerate research aiming at developing therapeutic agents that target EET formation or metabolism pathways.
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Affiliation(s)
- Rüdiger Kaspera
- University of Washington, Department of Medicinal Chemistry, Seattle, WA 98195, USA
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Naraharisetti SB, Lin YS, Rieder MJ, Marciante KD, Psaty BM, Thummel KE, Totah RA. Human liver expression of CYP2C8: gender, age, and genotype effects. Drug Metab Dispos 2010; 38:889-93. [PMID: 20190184 DOI: 10.1124/dmd.109.031542] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Research investigating CYP2C8 as a drug-metabolizing enzyme has gained momentum over the past few years. CYP2C8 is estimated to oxidatively metabolize approximately 5% of therapeutically prescribed drugs. It is polymorphically expressed, and several single nucleotide polymorphisms have been identified with varying effects on the clearance of CYP2C8 substrates. However, the human liver expression of CYP2C8 and effects of genetic variation, age, and gender on mRNA and protein levels have not been fully explored. In this report, interindividual variation in CYP2C8 mRNA and protein expression in 60 livers from white individuals was examined. The livers were genotyped for CYP2C8*3 and CYP2C8*4 polymorphisms. The effects of genotype, age, and gender on hepatic CYP2C8 expression and the correlation of CYP2C8 mRNA expression with CYP3A4 and other CYP2C members were evaluated. The mean +/- S.D. protein levels in CYP2C8*1/*1 livers was 30.8 +/- 17.5 pmol/mg protein, and a trend for decreased protein levels was observed for CYP2C8*1/*4 livers (15.8 +/- 9.7 pmol/mg, p = 0.07). The mean expression levels of CYP2C8 was comparable in males and females (p = 0.18). The mRNA expression of CYP2C8, CYP2C9, CYP2C19, and CYP3A4, but not CYP2C18, was highly correlated (p < 0.0001). Moreover, the hepatic CYP2C8 and CYP3A4 protein levels were strongly correlated (r = 0.76, p < 0.0001). This correlation is most likely due to common regulation factors for both genes. CYP2C8 mRNA or protein expression levels were not significantly affected by CYP2C8*3 or *4 genotype, gender, or age, and variation observed clinically in CYP2C8 activity warrants further investigation.
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Lee CA, Neul D, Clouser-Roche A, Dalvie D, Wester MR, Jiang Y, Jones JP, Freiwald S, Zientek M, Totah RA. Identification of novel substrates for human cytochrome P450 2J2. Drug Metab Dispos 2009; 38:347-56. [PMID: 19923256 DOI: 10.1124/dmd.109.030270] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Several antihistamine drugs including terfenadine, ebastine, and astemizole have been identified as substrates for CYP2J2. The overall importance of this enzyme in drug metabolism has not been fully explored. In this study, 139 marketed therapeutic agents and compounds were screened as potential CYP2J2 substrates. Eight novel substrates were identified that vary in size and overall topology from relatively rigid structures (amiodarone) to larger complex structures (cyclosporine). The substrates displayed in vitro intrinsic clearance values ranging from 0.06 to 3.98 mul/min/pmol CYP2J2. Substrates identified for CYP2J2 are also metabolized by CYP3A4. Extracted ion chromatograms of metabolites observed for albendazole, amiodarone, astemizole, thioridazine, mesoridazine, and danazol showed marked differences in the regioselectivity of CYP2J2 and CYP3A4. CYP3A4 commonly metabolized compounds at multiple sites, whereas CYP2J2 metabolism was more restrictive and limited, in general, to a single site for large compounds. Although the CYP2J2 active site can accommodate large substrates, it may be more narrow than CYP3A4, limiting metabolism to moieties that can extend closer toward the active heme iron. For albendazole, CYP2J2 forms a unique metabolite compared with CYP3A4. Albendazole and amiodarone were evaluated in various in vitro systems including recombinant CYP2J2 and CYP3A4, pooled human liver microsomes (HLM), and human intestinal microsomes (HIM). The Michaelis-Menten-derived intrinsic clearance of N-desethyl amiodarone was 4.6 greater in HLM than in HIM and 17-fold greater in recombinant CYP3A4 than in recombinant CYP2J2. The resulting data suggest that CYP2J2 may be an unrecognized participant in first-pass metabolism, but its contribution is minor relative to that of CYP3A4.
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Affiliation(s)
- Caroline A Lee
- Pfizer Global Research & Development, 10646 Science Center Dr., San Diego, CA 92121, USA.
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Totah RA, Allen KE, Sheffels P, Whittington D, Kharasch ED. Enantiomeric Metabolic Interactions and Stereoselective Human Methadone Metabolism. J Pharmacol Exp Ther 2007; 321:389-99. [PMID: 17259447 DOI: 10.1124/jpet.106.117580] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Methadone is administered as a racemate, although opioid activity resides in the R-enantiomer. Methadone disposition is stereoselective, with considerable unexplained variability in clearance and plasma R/S ratios. N-Demethylation of methadone in vitro is predominantly mediated by cytochrome P450 CYP3A4 and CYP2B6 and somewhat by CYP2C19. This investigation evaluated stereoselectivity, models, and kinetic parameters for methadone N-demethylation by recombinant CYP2B6, CYP3A4, and CYP2C19, and the potential for interactions between enantiomers during racemate metabolism. CYP2B6 metabolism was stereoselective. CYP2C19 was less active, and stereoselectivity was opposite that for CYP2B6. CYP3A4 was not stereoselective. With all three isoforms, enantiomer N-dealkylation rates in the racemate were lower than those of (R)-(6-dimethyamino-4,4-diphenyl-heptan-3-one) hydrochloride (R-methadone) or (S)-(6-dimethyamino-4,4-diphenyl-heptan-3-one) hydrochloride (S-methadone) alone, suggesting an enantiomeric interaction and mutual metabolic inhibition. For CYP2B6, the interaction between enantiomers was stereoselective, with S-methadone as a more potent inhibitor of R-methadone N-demethylation than R-of S-methadone. In contrast, enantiomer interactions were not stereoselective with CYP2C19 or CYP3A4. For all three cytochromes P450, methadone N-demethylation was best described by two-site enzyme models with competitive inhibition. There were minor model differences between cytochromes P450 to account for stereoselectivity of metabolism and enantiomeric interactions. Changes in plasma R/S methadone ratios observed after rifampin or troleandomycin pretreatment in humans in vivo were successfully predicted by CYP2B6- but not CYP3A4-catalyzed methadone N-demethylation. CYP2B6 is a predominant catalyst of stereoselective methadone metabolism in vitro. In vivo, CYP2B6 may be a major determinant of methadone metabolism and disposition, and CYP2B6 activity and stereoselective metabolic interactions may confer variability in methadone disposition.
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Affiliation(s)
- Rheem A Totah
- Department of Medicinal Chemistry, University of Washington. Seattle, Washington, USA
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Gaedigk A, Baker DW, Totah RA, Gaedigk R, Pearce RE, Vyhlidal CA, Zeldin DC, Leeder JS. Variability of CYP2J2 expression in human fetal tissues. J Pharmacol Exp Ther 2006; 319:523-32. [PMID: 16868033 PMCID: PMC1876721 DOI: 10.1124/jpet.106.109215] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
CYP2J2 metabolizes arachidonic acid to 20-hydroxyeicosatetraenoic acid and epoxyeicosatrienoic acids (EETs), which play a critical role in the regulation of renal, pulmonary, cardiac, and vascular function. However, the contribution of CYP2J2 to EET formation in the liver remains poorly characterized. Likewise, information is sparse regarding the extent and variability of CYP2J2 expression during human development. This investigation was undertaken to characterize the variability of CYP2J2 expression in fetal liver, heart, kidney, lung, intestine, and brain and in postnatal liver samples. CYP2J2 mRNA expression was measured using quantitative polymerase chain reaction, and immunoreactive CYP2J2 was examined using two anti-CYP2J2 antibodies. CYP2J2 mRNA was ubiquitously expressed in pre- and postnatal samples. Fetal hepatic mRNA expression varied 127-fold (1351 +/- 717 transcripts/ng total RNA), but this variation was reduced to 8-fold after exclusion of four samples with extremely low levels of mRNA. Amounts of immunoreactive protein also varied substantially among samples without an apparent relationship with transcript number or genotype. Western blot analysis revealed a different protein pattern between prenatal and postnatal liver samples. DNA resequencing of selected subjects identified a single novel single-nucleotide polymorphism (CYP2J2*10), which was found in only one subject and therefore did not explain the large variability in CYP2J2 protein content. In vitro expression suggests that the protein product of CYP2J2*10 confers reduced enzymatic activity. Aberrant splicing produces three minor transcripts, which were present in all samples tested. Due to premature termination codons, none encodes functional protein. The mechanisms leading to variable amounts of immunoreactive protein and distinct pre- and postnatal CYP2J2 protein patterns warrant further investigation.
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Affiliation(s)
- Andrea Gaedigk
- Children's Mercy Hospital, Division of Clinical Pharmacology, 2401 Gillham Rd., Kansas City, MO 64108, USA.
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Abstract
Cytochrome P450 (CYP) 2C8 [corrected] has been a relatively neglected member of the human CYP2C family. Over the period from 2000 through 2003, PubMed searches with the key word CYP2C8 returned only 10% to 15% of the citations obtained for all of the CYP2C enzymes combined. However, in the past year a crystal structure for CYP2C8 has been described, new inhibitors and probe substrates for the enzyme have been in development, the first case study was published linking CYP2C8 genetic polymorphisms to a disease state, and there has been an increasing awareness of the role that CYP2C8 plays in the disposition of therapeutic agents, especially from the pharmacogenetic and drug-drug interaction perspectives. This report discusses baseline characteristics of the enzyme and summarizes recent developments in these areas and their clinical relevance.
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Affiliation(s)
- Rheem A Totah
- Department of Medicinal Chemistry, University of Washington, Seattle, WA 98195, USA
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Huang W, Lin YS, McConn DJ, Calamia JC, Totah RA, Isoherranen N, Glodowski M, Thummel KE. EVIDENCE OF SIGNIFICANT CONTRIBUTION FROM CYP3A5 TO HEPATIC DRUG METABOLISM. Drug Metab Dispos 2004; 32:1434-45. [PMID: 15383492 DOI: 10.1124/dmd.104.001313] [Citation(s) in RCA: 126] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
CYP3A4 and CYP3A5 exhibit significant overlap in substrate specificity but can differ in product regioselectivity and formation activity. To further explore this issue, we compared the kinetics of product formation for eight different substrates, using heterologously expressed CYP3A4 and CYP3A5 and phenotyped human liver microsomes. Both enzymes displayed allosteric behavior toward six of the substrates. When it occurred, the "maximal" intrinsic clearance was used for quantitative comparisons. Based on this parameter, CYP3A5 was more active than CYP3A4 in catalyzing total midazolam hydroxylation (3-fold) and lidocaine demethylation (1.4-fold). CYP3A5 exhibited comparable metabolic activity as CYP3A4 (90-110%) toward dextromethorphan N-demethylation and carbamazepine epoxidation. CYP3A5-catalyzed erythromycin N-demethylation, total flunitrazepam hydroxylation, testosterone 6beta-hydroxylation, and terfenadine alcohol formation occurred with an intrinsic clearance that was less than 65% that of CYP3A4. Using two sets of human liver microsomes with equivalent CYP3A4-specific content but markedly different CYP3A5 content (group 1, predominantly CYP3A4; group 2, CYP3A4 + CYP3A5), we assessed the contribution of CYP3A5 to product formation rates determined at low substrate concentrations (< or = Km). Mean product formation rates for group 2 microsomes were 1.4- to 2.2-fold higher than those of group 1 (p < 0.05 for 5 of 8 substrates). After adjusting for CYP3A4 activity (itraconazole hydroxylation), mean product formation rates for group 2 microsomes were still significantly higher than those of group 1 (p < 0.05 for 3 substrates). We suggest that, under conditions when CYP3A5 content represents a significant fraction of the total hepatic CYP3A pool, the contribution of CYP3A5 to the clearance of some drugs may be an important source of interindividual variability.
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Affiliation(s)
- Weili Huang
- Department of Pharmaceutics, Box 357610, University of Washington, Seattle, WA 98195-7610, USA
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Totah RA, Hanzlik RP. Oxidative and Nonoxidative Decarboxylation of N-Alkyl-N-phenylglycines by Horseradish Peroxidase. Mechanistic Switching by Varying Hydrogen Peroxide, Oxygen, and Solvent Deuterium. Biochemistry 2004; 43:7907-14. [PMID: 15196035 DOI: 10.1021/bi049499q] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Horseradish peroxidase (HRP) typically oxidizes aniline derivatives using hydrogen peroxide as the oxidant. The action of HRP on N-alkyl-N-phenylglycine derivatives 1b-1e (PhN(R)CH(2)COOH; R = Me, Et, n-Pr, i-Pr, respectively) is highly unusual if not unique. Under standard peroxidatic conditions (HRP/H(2)O(2)/air), the major product (ca. 70%) is the secondary aniline 2b-2e (PhNHR) resulting from the expected oxidative decarboxylation process, but a significant amount (ca. 30%) of the related tertiary aniline PhN(CH(3))R (3b-3e) arises from an unexpected nonoxidative decarboxylation process. Under anaerobic, peroxide-free conditions only the tertiary anilines 3b-3e are formed in a reaction that is extremely rapid compared to those in which H(2)O(2), molecular oxygen, or both are present. In D(2)O buffers, the product is exclusively the monodeutero tertiary aniline PhN(CH(2)D)R and the reaction is much slower (k(H(2)O)/k(D(2)O) = 5.7), suggesting that a proton transfer step is substantially rate-limiting in turnover. It is proposed that ferric HRP oxidizes 1 to a cation radical, which then decarboxylates to an alpha-amino radical having carbanion character on carbon; protonation of the latter, followed by electron capture from ferrous HRP, completes the cycle. Hydrogen peroxide and oxygen slow turnover by diverting ferric HRP toward the compound I/compound II forms or toward compound III, respectively. Finally, under peroxidatic conditions, 1a (R = cyclopropyl) inactivates HRP with concurrent formation of 2a but not N-phenylglycine, but under anaerobic, peroxide-free conditions, 1a inactivates HRP almost instantly with no detectable product formation.
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Affiliation(s)
- Rheem A Totah
- Department of Medicinal Chemistry, University of Kansas, Lawrence, Kansas 66045, USA
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Abstract
Under anaerobic, peroxide-free conditions (pH 5.5, 25 degrees C), horseradish peroxidase (HRP) catalyzes the rapid, non-oxidatve decarboxylation of N-alkyl-N-phenylglycine derivatives to the corresponding N-alkyl-N-methylanilines in 100% yield. When the reaction is conducted in D2O buffer, the product contains a single deuterium in the methyl group. The reactions are very fast compared to the oxidative decarboxylation of the same substrates under standard peroxidatic conditions (i.e., hydrogen peroxide added, air present) and in fact are inhibited by peroxide and oxygen. To account for these unprecedented observations, we propose a cyclic mechanism in which ferric HRP abstracts an electron from the substrate, giving an aminium ion intermediate that decarboxylates; protonation of the resulting alpha-aminoradical on carbon gives an aminium ion that is reduced by ferrous HRP to complete the cycle.
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Affiliation(s)
- Rheem A Totah
- Department of Medicinal Chemistry, University of Kansas, Lawrence 66045-7582, USA
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Affiliation(s)
- R A Totah
- Department of Medicinal Chemistry, University of Kansas, Malott Hall 4048, 1251 Wescoe Hall Drive, Lawrence, Kansas 66045-7582, USA
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