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Zheng H, Wu H, Wang D, Wang S, Ji D, Liu X, Gao G, Su X, Zhang Y, Ling Y. Research progress of prodrugs for the treatment of cerebral ischemia. Eur J Med Chem 2024; 272:116457. [PMID: 38704941 DOI: 10.1016/j.ejmech.2024.116457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Revised: 04/20/2024] [Accepted: 04/25/2024] [Indexed: 05/07/2024]
Abstract
It is well-known that pharmacotherapy plays a pivotal role in the treatment and prevention of cerebral ischemia. Nevertheless, existing drugs, including numerous natural products, encounter various challenges when applied in cerebral ischemia treatment. These challenges comprise poor brain absorption due to low blood-brain barrier (BBB) permeability, limited water solubility, inadequate bioavailability, poor stability, and rapid metabolism. To address these issues, researchers have turned to prodrug strategies, aiming to mitigate or eliminate the adverse properties of parent drug molecules. In vivo metabolism or enzymatic reactions convert prodrugs into active parent drugs, thereby augmenting BBB permeability, improving bioavailability and stability, and reducing toxicity to normal tissues, ultimately aiming to enhance treatment efficacy and safety. This comprehensive review delves into multiple effective prodrug strategies, providing a detailed description of representative prodrugs developed over the past two decades. It underscores the potential of prodrug approaches to improve the therapeutic outcomes of currently available drugs for cerebral ischemia. The publication of this review serves to enrich current research progress on prodrug strategies for the treatment and prevention of cerebral ischemia. Furthermore, it seeks to offer valuable insights for pharmaceutical chemists in this field, offer guidance for the development of drugs for cerebral ischemia, and provide patients with safer and more effective drug treatment options.
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Affiliation(s)
- Hongwei Zheng
- School of Pharmacy, Nantong Key Laboratory of Small Molecular Drug Innovation, Jiangsu Province Key Laboratory for Inflammation and Molecular Drug Target, Nantong University, 226001, Nantong, Jiangsu, PR China
| | - Hongmei Wu
- School of Pharmacy, Nantong Key Laboratory of Small Molecular Drug Innovation, Jiangsu Province Key Laboratory for Inflammation and Molecular Drug Target, Nantong University, 226001, Nantong, Jiangsu, PR China; Department of Neurosurgery, Affiliated Hospital of Nantong University, 226001, Nantong, Jiangsu, PR China
| | - Dezhi Wang
- School of Pharmacy, Nantong Key Laboratory of Small Molecular Drug Innovation, Jiangsu Province Key Laboratory for Inflammation and Molecular Drug Target, Nantong University, 226001, Nantong, Jiangsu, PR China; Department of Neurosurgery, Affiliated Hospital of Nantong University, 226001, Nantong, Jiangsu, PR China
| | - Sijia Wang
- School of Pharmacy, Nantong Key Laboratory of Small Molecular Drug Innovation, Jiangsu Province Key Laboratory for Inflammation and Molecular Drug Target, Nantong University, 226001, Nantong, Jiangsu, PR China; Department of Neurosurgery, Affiliated Hospital of Nantong University, 226001, Nantong, Jiangsu, PR China
| | - Dongliang Ji
- School of Pharmacy, Nantong Key Laboratory of Small Molecular Drug Innovation, Jiangsu Province Key Laboratory for Inflammation and Molecular Drug Target, Nantong University, 226001, Nantong, Jiangsu, PR China; Department of Neurosurgery, Affiliated Hospital of Nantong University, 226001, Nantong, Jiangsu, PR China
| | - Xiao Liu
- School of Pharmacy, Nantong Key Laboratory of Small Molecular Drug Innovation, Jiangsu Province Key Laboratory for Inflammation and Molecular Drug Target, Nantong University, 226001, Nantong, Jiangsu, PR China
| | - Ge Gao
- School of Pharmacy, Nantong Key Laboratory of Small Molecular Drug Innovation, Jiangsu Province Key Laboratory for Inflammation and Molecular Drug Target, Nantong University, 226001, Nantong, Jiangsu, PR China
| | - Xing Su
- Department of Neurosurgery, Affiliated Hospital of Nantong University, 226001, Nantong, Jiangsu, PR China.
| | - Yanan Zhang
- School of Pharmacy, Nantong Key Laboratory of Small Molecular Drug Innovation, Jiangsu Province Key Laboratory for Inflammation and Molecular Drug Target, Nantong University, 226001, Nantong, Jiangsu, PR China.
| | - Yong Ling
- School of Pharmacy, Nantong Key Laboratory of Small Molecular Drug Innovation, Jiangsu Province Key Laboratory for Inflammation and Molecular Drug Target, Nantong University, 226001, Nantong, Jiangsu, PR China.
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Tokudome Y, Katayanagi M, Hashimoto F. Esterase Activity and Intracellular Localization in Reconstructed Human Epidermal Cultured Skin Models. Ann Dermatol 2015; 27:269-74. [PMID: 26082583 PMCID: PMC4466279 DOI: 10.5021/ad.2015.27.3.269] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 09/15/2014] [Accepted: 09/17/2014] [Indexed: 11/23/2022] Open
Abstract
Background Reconstructed human epidermal culture skin models have been developed for cosmetic and pharmaceutical research. Objective This study evaluated the total and carboxyl esterase activities (i.e., Km and Vmax, respectively) and localization in two reconstructed human epidermal culture skin models (LabCyte EPI-MODEL [Japan Tissue Engineering] and EpiDerm [MatTek/Kurabo]). The usefulness of the reconstruction cultured epidermis was also verified by comparison with human and rat epidermis. Methods Homogenized epidermal samples were fractioned by centrifugation. p-nitrophenyl acetate and 4-methylumbelliferyl acetate were used as substrates of total esterase and carboxyl esterase, respectively. Results Total and carboxyl esterase activities were present in the reconstructed human epidermal culture skin models and were localized in the cytosol. Moreover, the activities and localization were the same as those in human and rat epidermis. Conclusion LabCyte EPI-MODEL and EpiDerm are potentially useful for esterase activity prediction in human epidermis.
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Affiliation(s)
- Yoshihiro Tokudome
- Laboratory of Dermatological Physiology, Faculty of Pharmaceutical Sciences, Josai University, Sakado, Japan
| | - Mishina Katayanagi
- Laboratory of Dermatological Physiology, Faculty of Pharmaceutical Sciences, Josai University, Sakado, Japan
| | - Fumie Hashimoto
- Laboratory of Dermatological Physiology, Faculty of Pharmaceutical Sciences, Josai University, Sakado, Japan
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Sodhi JK, Wong S, Kirkpatrick DS, Liu L, Khojasteh SC, Hop CECA, Barr JT, Jones JP, Halladay JS. A novel reaction mediated by human aldehyde oxidase: amide hydrolysis of GDC-0834. Drug Metab Dispos 2015; 43:908-15. [PMID: 25845827 DOI: 10.1124/dmd.114.061804] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 04/06/2015] [Indexed: 12/31/2022] Open
Abstract
GDC-0834, a Bruton's tyrosine kinase inhibitor investigated as a potential treatment of rheumatoid arthritis, was previously reported to be extensively metabolized by amide hydrolysis such that no measurable levels of this compound were detected in human circulation after oral administration. In vitro studies in human liver cytosol determined that GDC-0834 (R)-N-(3-(6-(4-(1,4-dimethyl-3-oxopiperazin-2-yl)phenylamino)-4-methyl-5-oxo- 4,5-dihydropyrazin-2-yl)-2-methylphenyl)-4,5,6,7-tetrahydrobenzo[b] thiophene-2-carboxamide) was rapidly hydrolyzed with a CLint of 0.511 ml/min per milligram of protein. Aldehyde oxidase (AO) and carboxylesterase (CES) were putatively identified as the enzymes responsible after cytosolic fractionation and mass spectrometry-proteomics analysis of the enzymatically active fractions. Results were confirmed by a series of kinetic experiments with inhibitors of AO, CES, and xanthine oxidase (XO), which implicated AO and CES, but not XO, as mediating GDC-0834 amide hydrolysis. Further supporting the interaction between GDC-0834 and AO, GDC-0834 was shown to be a potent reversible inhibitor of six known AO substrates with IC50 values ranging from 0.86 to 1.87 μM. Additionally, in silico modeling studies suggest that GDC-0834 is capable of binding in the active site of AO with the amide bond of GDC-0834 near the molybdenum cofactor (MoCo), orientated in such a way to enable potential nucleophilic attack on the carbonyl of the amide bond by the hydroxyl of MoCo. Together, the in vitro and in silico results suggest the involvement of AO in the amide hydrolysis of GDC-0834.
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Affiliation(s)
- Jasleen K Sodhi
- Departments of Drug Metabolism and Pharmacokinetics (J.K.S., S.W., S.C.K., C.E.C.A.H., J.S.H.), Clinical Pharmacology (L.L.), and Protein Chemistry (D.S.K.), Genentech, Inc., South San Francisco, California; and Department of Chemistry, Washington State University, Pullman, Washington (J.T.B., J.P.J.)
| | - Susan Wong
- Departments of Drug Metabolism and Pharmacokinetics (J.K.S., S.W., S.C.K., C.E.C.A.H., J.S.H.), Clinical Pharmacology (L.L.), and Protein Chemistry (D.S.K.), Genentech, Inc., South San Francisco, California; and Department of Chemistry, Washington State University, Pullman, Washington (J.T.B., J.P.J.)
| | - Donald S Kirkpatrick
- Departments of Drug Metabolism and Pharmacokinetics (J.K.S., S.W., S.C.K., C.E.C.A.H., J.S.H.), Clinical Pharmacology (L.L.), and Protein Chemistry (D.S.K.), Genentech, Inc., South San Francisco, California; and Department of Chemistry, Washington State University, Pullman, Washington (J.T.B., J.P.J.)
| | - Lichuan Liu
- Departments of Drug Metabolism and Pharmacokinetics (J.K.S., S.W., S.C.K., C.E.C.A.H., J.S.H.), Clinical Pharmacology (L.L.), and Protein Chemistry (D.S.K.), Genentech, Inc., South San Francisco, California; and Department of Chemistry, Washington State University, Pullman, Washington (J.T.B., J.P.J.)
| | - S Cyrus Khojasteh
- Departments of Drug Metabolism and Pharmacokinetics (J.K.S., S.W., S.C.K., C.E.C.A.H., J.S.H.), Clinical Pharmacology (L.L.), and Protein Chemistry (D.S.K.), Genentech, Inc., South San Francisco, California; and Department of Chemistry, Washington State University, Pullman, Washington (J.T.B., J.P.J.)
| | - Cornelis E C A Hop
- Departments of Drug Metabolism and Pharmacokinetics (J.K.S., S.W., S.C.K., C.E.C.A.H., J.S.H.), Clinical Pharmacology (L.L.), and Protein Chemistry (D.S.K.), Genentech, Inc., South San Francisco, California; and Department of Chemistry, Washington State University, Pullman, Washington (J.T.B., J.P.J.)
| | - John T Barr
- Departments of Drug Metabolism and Pharmacokinetics (J.K.S., S.W., S.C.K., C.E.C.A.H., J.S.H.), Clinical Pharmacology (L.L.), and Protein Chemistry (D.S.K.), Genentech, Inc., South San Francisco, California; and Department of Chemistry, Washington State University, Pullman, Washington (J.T.B., J.P.J.)
| | - Jeffrey P Jones
- Departments of Drug Metabolism and Pharmacokinetics (J.K.S., S.W., S.C.K., C.E.C.A.H., J.S.H.), Clinical Pharmacology (L.L.), and Protein Chemistry (D.S.K.), Genentech, Inc., South San Francisco, California; and Department of Chemistry, Washington State University, Pullman, Washington (J.T.B., J.P.J.)
| | - Jason S Halladay
- Departments of Drug Metabolism and Pharmacokinetics (J.K.S., S.W., S.C.K., C.E.C.A.H., J.S.H.), Clinical Pharmacology (L.L.), and Protein Chemistry (D.S.K.), Genentech, Inc., South San Francisco, California; and Department of Chemistry, Washington State University, Pullman, Washington (J.T.B., J.P.J.)
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Campbell JL, Yoon M, Clewell HJ. A case study on quantitative in vitro to in vivo extrapolation for environmental esters: Methyl-, propyl- and butylparaben. Toxicology 2015; 332:67-76. [PMID: 25839974 DOI: 10.1016/j.tox.2015.03.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 01/19/2015] [Accepted: 03/09/2015] [Indexed: 10/23/2022]
Abstract
Parabens have been reported as potential endocrine disrupters and are widely used in consumer projects including cosmetics, foods and pharmaceuticals. We report on the development of a PBPK model for methyl-, propyl-, and butylparaben. The model was parameterized through a combination of QSAR for tissue solubility and quantitative in vitro to in vivo extrapolation (IVIVE) for hydrolysis in portals of entry including intestine and skin as well as in the primary site of metabolism, the liver. Overall, the model provided very good agreement with published time-course data in blood and urine from controlled dosing studies in rat and human, and demonstrates the potential value of quantitative IVIVE in expanding the use of human biomonitoring data in safety assessment. An in vitro based cumulative margin of safety (MOS) was calculated by comparing the effective concentrations from an in vitro assay of estrogenicity to the free paraben concentrations predicted by the model to be associated with the 95th percentile urine concentrations reported in NHANES (2009-2010 collection period). The calculated MOS for adult females was 108, whereas the MOS for males was 444.
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Affiliation(s)
- Jerry L Campbell
- The Hamner Institutes for Health Sciences, 6 Davis Drive, Research Triangle Park, NC 27709, USA.
| | - Miyoung Yoon
- The Hamner Institutes for Health Sciences, 6 Davis Drive, Research Triangle Park, NC 27709, USA
| | - Harvey J Clewell
- The Hamner Institutes for Health Sciences, 6 Davis Drive, Research Triangle Park, NC 27709, USA
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Matsuda D, Ohshiro T, Ohtawa M, Yamazaki H, Nagamitsu T, Tomoda H. In vitro metabolism of pyripyropene A and ACAT inhibitory activity of its metabolites. J Antibiot (Tokyo) 2015; 68:27-34. [PMID: 25005817 DOI: 10.1038/ja.2014.91] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 05/12/2014] [Accepted: 06/10/2014] [Indexed: 11/09/2022]
Abstract
Pyripyropene A (PPPA, 1) of fungal origin, a selective inhibitor of acyl-CoA:cholesterol acyltransferase 2 (ACAT2), proved orally active in atherogenic mouse models. The in vitro metabolites of 1 in liver microsomes and plasma of human, rabbit, rat and mouse were analyzed by ultra fast liquid chromatography and liquid chromatography/tandem mass spectrometry. In the liver microsomes from all species, successive hydrolysis occurred at the 1-O-acetyl residue, then at the 11-O-acetyl residue of 1, while the 7-O-acetyl residue was resistant to hydrolysis. Furthermore, dehydrogenation of the newly generated 11-alcoholic hydroxyl residue occurred in human and mouse-liver microsomes, while oxidation of the pyridine ring occurred in human and rabbit liver microsomes. On the other hand, hydrolysis of the 7-O-acetyl residue proceeded only in the mouse plasma. These data indicated that the in vitro metabolic profiles of 1 have subtle differences among animal species. All of the PPPA metabolites observed in liver microsomes and plasma markedly decreased ACAT2 inhibitory activity. These findings will help us to synthesize new PPPA derivatives more effective in in vivo study than 1.
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Affiliation(s)
- Daisuke Matsuda
- Graduate School of Pharmaceutical Sciences, Kitasato University, Tokyo, Japan
| | - Taichi Ohshiro
- 1] Graduate School of Pharmaceutical Sciences, Kitasato University, Tokyo, Japan [2] Section on Lipid Sciences, Department of Pathology, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Masaki Ohtawa
- Graduate School of Pharmaceutical Sciences, Kitasato University, Tokyo, Japan
| | - Hiroyuki Yamazaki
- Graduate School of Pharmaceutical Sciences, Kitasato University, Tokyo, Japan
| | - Tohru Nagamitsu
- Graduate School of Pharmaceutical Sciences, Kitasato University, Tokyo, Japan
| | - Hiroshi Tomoda
- Graduate School of Pharmaceutical Sciences, Kitasato University, Tokyo, Japan
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Uibel F, Schwarz M. Prediction of embryotoxic potential using the ReProGlo stem cell-based Wnt reporter assay. Reprod Toxicol 2014; 55:30-49. [PMID: 25263227 DOI: 10.1016/j.reprotox.2014.09.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 07/18/2014] [Accepted: 09/15/2014] [Indexed: 01/07/2023]
Abstract
The ReProGlo assay was developed in 2009 to predict embryotoxic potential of drugs and chemicals by use of a stem cell-based in vitro system. It utilizes a luciferase reporter to detect drug-induced alterations in the canonical Wnt/β-catenin signaling pathway, which is involved in regulation of early embryonic development. It allows the simultaneous determination of cell viability and luciferase reporter activity in a high throughput format. The present study was conducted within the framework of the EU ChemScreen-project. It (1) enlarges the original number of test-compounds from 17 to now 80, (2) introduces a new classification scheme and (3) anchors the results against a prediction scheme based on structural features of chemicals. The assay is applicable as stand-alone for priority setting or in a test battery.
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Affiliation(s)
- Frederik Uibel
- Institute of Experimental and Clinical Pharmacology and Toxicology, Department of Toxicology, Wilhelmstr. 56, 72074 Tübingen, Germany
| | - Michael Schwarz
- Institute of Experimental and Clinical Pharmacology and Toxicology, Department of Toxicology, Wilhelmstr. 56, 72074 Tübingen, Germany.
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Eichenbaum G, Skibbe J, Parkinson A, Johnson MD, Baumgardner D, Ogilvie B, Usuki E, Tonelli F, Holsapple J, Schmitt-Hoffmann A. Use of enzyme inhibitors to evaluate the conversion pathways of ester and amide prodrugs: a case study example with the prodrug ceftobiprole medocaril. J Pharm Sci 2011; 101:1242-52. [PMID: 22095741 DOI: 10.1002/jps.22816] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Revised: 10/19/2011] [Accepted: 10/21/2011] [Indexed: 11/10/2022]
Abstract
An approach was developed that uses enzyme inhibitors to support the assessment of the pathways that are responsible for the conversion of intravenously administered ester and amide prodrugs in different biological matrices. The methodology was applied to ceftobiprole medocaril (BAL5788), the prodrug of the cephalosporin antibiotic, ceftobiprole. The prodrug was incubated in plasma, postmitochondrial supernatant fractions from human liver (impaired and nonimpaired), kidney, and intestine as well as erythrocytes, in the presence and absence of different enzyme inhibitors (acetylcholinesterase, pseudocholinesterase, retinyl palmitoyl hydrolase, serine esterases, amidases, and cholinesterase). Hydrolysis was rapid, extensive, and not dependent on the presence of β-nicotinamide-adenine dinucleotide phosphate (reduced form) in all matrices tested, suggesting the involvement of carboxylesterases but not P450 enzymes. Hydrolysis in healthy human plasma was rapid and complete and only partially inhibited in the presence of paraoxonase inhibitors or in liver from hepatic impaired patients, suggesting involvement of nonparaoxonase pathways. The results demonstrate the utility of this approach in confirming the presence of multiple conversion pathways of intravenously administered prodrugs and in the case of BAL5788 demonstrated that this prodrug is unlikely to be affected by genetic polymorphisms, drug interactions, or other environmental factors that might inhibit or induce the enzymes involved in its conversion.
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Affiliation(s)
- Gary Eichenbaum
- Johnson & Johnson Pharmaceutical Research & Development, L.L.C., Raritan, New Jersey 08869, USA.
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Nagahori H, Matsunaga H, Tomigahara Y, Isobe N, Kaneko H. Metabolism of flufenpyr-ethyl in rats and mice. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2009; 57:4872-4877. [PMID: 19397263 DOI: 10.1021/jf9011592] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The metabolism of flufenpyr-ethyl [ethyl 2-chloro-5-[1,6-dihydro-5-methyl-6-oxo-4-(trifluoromethyl)pyridazin-1-yl]-4-fluorophenoxyacetate] was examined in rats and mice. [Phenyl-(14)C]flufenpyr-ethyl was administered to rats and mice as a single oral dose at a level of 500 mg/kg, and (14)C-excretion was examined. Total (14)C-recoveries within 7 days after administration were 93.2 to 97.5% (feces, 42.0 to 46.0%; and urine, 47.2 to 55.5%) in rats and 92.6 to 96.4% (feces, 26.7 to 32.7%; and urine, 59.9 to 69.7%) in mice. (14)C-Excretion into expired air was not detected in rats (expired air of mice was not analyzed). No marked species- or sex-related differences were observed in the rate of (14)C-elimination, but a relatively higher excretion into the urine of mice was observed compared to that in rats. (14)C-residues in tissue 7 days after administration were relatively high for liver, hair, skin, and kidney, but total (14)C-residues were low, below 0.2% of the dose. An ester cleaved metabolite (S-3153acid) was the major metabolite in feces and urine. Hydroxylation of the methyl group on the C5 of the pyridazine ring and ether cleavage were also observed. No sex-related differences were observed in (14)C-elimination, (14)C-distribution, and metabolite profiles, and metabolism of flufenpyr-ethyl in rats and mice was similar. In vitro metabolism of flufenpyr-ethyl was examined using stomach and intestinal contents and blood and liver S9 fractions (postmitochondrial supernatant fractions) in rats. S-3153acid was detected as a major metabolite in the presence of intestinal contents and blood and liver S9 fractions, and a small amount was also formed in the presence of stomach contents, indicating that the parent compound is rapidly metabolized by intestinal contents and blood and liver S9 fractions through ester cleavage.
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Affiliation(s)
- Hirohisa Nagahori
- Environmental Health Science Laboratory, Sumitomo Chemical Co, Ltd, Kasugade-Naka, Osaka, Japan.
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Knaak JB, Dary CC, Power F, Thompson CB, Blancato JN. Physicochemical and Biological Data for the Development of Predictive Organophosphorus Pesticide QSARs and PBPK/PD Models for Human Risk Assessment. Crit Rev Toxicol 2008; 34:143-207. [PMID: 15112752 DOI: 10.1080/10408440490432250] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
A search of the scientific literature was carried out for physiochemical and biological data [i.e., IC50, LD50, Kp (cm/h) for percutaneous absorption, skin/water and tissue/blood partition coefficients, inhibition ki values, and metabolic parameters such as Vmax and Km] on 31 organophosphorus pesticides (OPs) to support the development of predictive quantitative structure-activity relationship (QSAR) and physiologically based pharmacokinetic and pharmacodynamic (PBPK/PD) models for human risk assessment. Except for work on parathion, chlorpyrifos, and isofenphos, very few modeling data were found on the 31 OPs of interest. The available percutaneous absorption, partition coefficients and metabolic parameters were insufficient in number to develop predictive QSAR models. Metabolic kinetic parameters (Vmax, Km) varied according to enzyme source and the manner in which the enzymes were characterized. The metabolic activity of microsomes should be based on the kinetic activity of purified or cDNA-expressed cytochrome P450s (CYPs) and the specific content of each active CYP in tissue microsomes. Similar requirements are needed to assess the activity of tissue A- and B-esterases metabolizing OPs. A limited amount of acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and carboxylesterase (CaE) inhibition and recovery data were found in the literature on the 31 OPs. A program is needed to require the development of physicochemical and biological data to support risk assessment methodologies involving QSAR and PBPK/PD models.
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Affiliation(s)
- James B Knaak
- Department of Pharmacology and Toxicology, School of Medicine and Biomedical Sciences, SUNY at Buffalo, Buffalo, New York 14214, USA.
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Cribb AE, Peyrou M, Muruganandan S, Schneider L. The Endoplasmic Reticulum in Xenobiotic Toxicity. Drug Metab Rev 2008; 37:405-42. [PMID: 16257829 DOI: 10.1080/03602530500205135] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The endoplasmic reticulum (ER) is involved in an array of cellular functions that play important roles in xenobiotic toxicity. The ER contains the majority of cytochrome P450 enzymes involved in xenobiotic metabolism, as well as a number of conjugating enzymes. In addition to its role in drug bioactivation and detoxification, the ER can be a target for damage by reactive intermediates leading to cell death or immune-mediated toxicity. The ER contains a set of luminal proteins referred to as ER stress proteins (including GRP78, GRP94, protein disulfide isomerase, and calreticulin). These proteins help regulate protein processing and folding of membrane and secretory proteins in the ER, calcium homeostasis, and ER-associated apoptotic pathways. They are induced in response to ER stress. This review discusses the importance of the ER in molecular events leading to cell death following xenobiotic exposure. Data showing that the ER is important in both renal and hepatic toxicity will be discussed.
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Affiliation(s)
- Alastair E Cribb
- Laboratory of Comparative Pharmacogenetics, Department of Biomedical Sciences, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PEI, Canada.
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Yamaori S, Ukena E, Fujiyama N, Funahashi T, Kimura T, Yamamoto I, Ohshima T, Matsumura K, Oda M, Watanabe K. Nafamostat is hydrolysed by human liver cytosolic long-chain acyl-CoA hydrolase. Xenobiotica 2008; 37:260-70. [PMID: 17624024 DOI: 10.1080/00498250601167091] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Although the authors recently reported that nafamostat, a clinically used serine protease inhibitor, was mainly hydrolysed by carboxylesterase in human liver microsomes, the involvement of human liver cytosol has not been elucidated. The current study examined the in vitro metabolism of nafamostat with human liver cytosols. Kinetic analysis indicated that the Vmax and Km values in the liver cytosols were 9.82 nmolmin(-1) mg(-1) protein and 197 microM for a liver sample HL-1, and 15.1 nmolmin(-1) mg(-1) protein and 157 microM for HL-2, respectively. The Vmax/Km values in both cytosols were at least threefold higher than those in the corresponding microsomes. The liver cytosolic activity for nafamostat hydrolysis was inhibited by phenylmethylsulfonyl fluoride (PMSF) (43% inhibition at 100 microM), whereas diisopropyl fluorophosphate (DFP) and bis(p-nitrophenyl)phosphate (BNPP) failed to inhibit the activity. Furthermore, the hydrolytic activity was also reduced by palmitoyl-CoA (67% inhibition at 100 microM) but not by acetyl-CoA. Effects of PMSF, DFP and BNPP on cytosolic palmitoyl-CoA hydrolytic activity were comparable with those of the cytosolic nafamostat hydrolytic activity. In addition, the palmitoyl-CoA hydrolytic activity was competitively inhibited by nafamostat with the apparent Ki value of 164 microM for the liver cytosol from HL-2. These results suggest that an isoform of long-chain acyl-CoA hydrolase may be responsible for the nafamostat hydrolysis in human liver cytosol.
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Affiliation(s)
- S Yamaori
- Faculty of Pharmaceutical Sciences, Department of Hygienic Chemistry, Hokuriku University, Kanazawa, Japan
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Nave R, McCracken N. Metabolism of ciclesonide in the upper and lower airways: review of available data. J Asthma Allergy 2008; 1:11-8. [PMID: 21436981 PMCID: PMC3121338 DOI: 10.2147/jaa.s4051] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Ciclesonide is a novel corticosteroid (CS) for the treatment of asthma and allergic rhinitis. After administration, the parent compound ciclesonide is converted by intracellular airway esterases to its pharmacologically active metabolite desisobutyryl-ciclesonide (des-CIC). We investigated the in vitro activation of ciclesonide and further esterification of des-CIC to (mainly) des-CIC oleate in several human target organ test systems. Human precision-cut lung slices, alveolar type II epithelial cells (A549), normal bronchial epithelial cells (NHBE), and nasal epithelial cells (HNEC) were incubated with ciclesonide. Enzymes characterization and the determination of the reversibility of fatty acid esterification was investigated in HNEC and NHBE. Ciclesonide was taken up and converted to des-CIC in all cellular test systems. Intracellular concentrations of des-CIC were maintained for up to 24 h. Formation of des-CIC oleate increased over time in HNEC, A549 cells, and lung slices. The formed des-CIC fatty acid conjugates were reconverted to des-CIC. Increasing concentrations of carboxylesterase and cholinesterase inhibitors progressively reduced the formation of metabolites. The results derived from these studies demonstrate the activation of ciclesonide to des-CIC in the upper and lower airways. The reversible formation of des-CIC fatty acid conjugates may prolong the anti-inflammatory activity of des-CIC and may allow for once-daily dosing.
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[14C]Benzyl acetate is a potential radiotracer for the measurement of glial metabolism in the rat brain. Nucl Med Biol 2007; 34:939-44. [DOI: 10.1016/j.nucmedbio.2007.06.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2007] [Revised: 06/21/2007] [Accepted: 06/26/2007] [Indexed: 11/20/2022]
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Jewell C, Prusakiewicz JJ, Ackermann C, Payne NA, Fate G, Williams FM. The distribution of esterases in the skin of the minipig. Toxicol Lett 2007; 173:118-23. [PMID: 17719730 DOI: 10.1016/j.toxlet.2007.07.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2007] [Accepted: 07/13/2007] [Indexed: 11/15/2022]
Abstract
Skin esterases serve an important pharmacological function as they can be utilised for activation of topically applied ester prodrugs. Understanding the nature of these enzymes, with respect to their role and local activity, is essential to defining the efficacy of ester prodrugs. Minipigs are used as models to study the kinetics of absorption of topically applied drugs. Their skin has structural properties very similar to human skin. However, regional distribution differences in esterase activity from site-to-site could influence cross-species extrapolation. Investigation of the regional site variation of minipig skin esterase activity will facilitate standardization of topically applied drug studies. Furthermore, the characterization of regional skin variation, will aid in translation of minipig results to better predictions of human esterase activity. Here we report the variation in rates of hydrolysis by minipig skin taken from different regional sites, using the esterase-selective substrates: phenyl valerate (carboxylesterase), phenyl acetate (arylesterase) and p-nitrophenyl acetate (general esterase). Skin from ears and back of male minipig showed higher activity than female. Skin from minipig ears and the back showed the highest level of esterase activity and was similar to human breast skin used in vitro absorption studies. These results suggest that skin from the minipig back is an appropriate model for preclinical human skin studies, particularly breast skin. This study supports the use of the minipig, with topical application to the back, as a model for the investigation of pharmacokinetics and metabolism of ester prodrugs.
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Affiliation(s)
- Christopher Jewell
- Toxicology Unit, School of Clinical and Laboratory Sciences, University of Newcastle upon Tyne, Newcastle upon Tyne NE2 4EA, UK
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16
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Inoue O, Hosoi R, Momosaki S, Yamamoto K, Amitani M, Yamaguchi M, Gee A. Evaluation of [14C]phenylacetate as a prototype tracer for the measurement of glial metabolism in the rat brain. Nucl Med Biol 2006; 33:985-9. [DOI: 10.1016/j.nucmedbio.2006.08.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2006] [Revised: 08/21/2006] [Accepted: 08/29/2006] [Indexed: 10/23/2022]
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17
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Abstract
Enzymes are essential for the activation of many prodrugs. In this review, the most important enzymes (e.g., paraoxonase, carboxylesterase, acetylcholinesterase, cholinesterase) involved in the bioconversion of ester-based prodrugs will be discussed in terms of their biology and biochemistry. Most of these enzymes fall into the category of hydrolytic enzymes. However, nonhydrolytic enzymes, including cytochrome P450s, can also catalyze the bioconversion of ester prodrugs and thus will be discussed here. Other factors influencing the ability of these enzymes to catalyze the bioconversion of ester-based prodrugs, particularly species and interindividual differences and stereochemical and structural features of the prodrugs, will be discussed.
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Affiliation(s)
- Bianca M Liederer
- Department of Pharmaceutical Chemistry, The University of Kansas, 2095 Constant Avenue, Lawrence, KS 66047, USA
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18
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Polsky-Fisher SL, Cao H, Lu P, Gibson CR. Effect of cytochromes P450 chemical inhibitors and monoclonal antibodies on human liver microsomal esterase activity. Drug Metab Dispos 2006; 34:1361-6. [PMID: 16720683 DOI: 10.1124/dmd.106.009704] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Selective and nonselective cytochromes P450 (P450) chemical inhibitors and monoclonal antibodies (mAbs) are routinely used to determine the contribution of P450 enzymes involved in the biotransformation of a drug. A fluorometric assay has been established using fluorescein diacetate as a model substrate to determine the effect of some commonly used P450 inhibitors and mAbs on human liver microsomal esterase activity. Of those inhibitors studied, only alpha-naphthoflavone, clotrimazole, ketoconazole, miconazole, nicardipine, and verapamil significantly inhibited human liver microsomal esterase activity, with apparent IC50 values of 18.0, 20.5, 6.5, 15.0, 19.4, and 5.4 microM, respectively. All of these showed > or =20% inhibition of human liver microsomal esterase activity at concentrations typically used for P450 reaction phenotyping studies, with clotrimazole, miconazole, nicardipine, and verapamil showing >60% inhibition. Unlike the chemical inhibitors, no inhibition of human liver microsomal esterase activity was observed in the presence of mAb to CYP1A2, 2C8, 2C9, 2C19, 2D6, and 3A4. These results suggest that P450 chemical inhibitors are capable of inhibiting human liver microsomal esterase activity and should not be used to assess the role of P450 enzymes in the biotransformation of esters. The lack of inhibition of human liver microsomal esterase activity by P450-specific monoclonal antibodies suggests that they may be used to assess the role of P450 enzymes in the biotransformation of esters. Additional experiments to assess the contribution of oxidative enzymes in the metabolism of esters may include incubations in the presence and absence of beta-nicotinamide adenine dinucleotide 2'-phosphate reduced.
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Affiliation(s)
- Stacey L Polsky-Fisher
- M.S., Department of Drug Metabolism, WP75B-200, Merck Research Laboratories, West Point, PA 19486, USA.
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Yamaori S, Fujiyama N, Kushihara M, Funahashi T, Kimura T, Yamamoto I, Sone T, Isobe M, Ohshima T, Matsumura K, Oda M, Watanabe K. Involvement of Human Blood Arylesterases and Liver Microsomal Carboxylesterases in Nafamostat Hydrolysis. Drug Metab Pharmacokinet 2006; 21:147-55. [PMID: 16702735 DOI: 10.2133/dmpk.21.147] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Metabolism of nafamostat, a clinically used serine protease inhibitor, was investigated with human blood and liver enzyme sources. All the enzyme sources examined (whole blood, erythrocytes, plasma and liver microsomes) showed nafamostat hydrolytic activity. V(max) and K(m) values for the nafamostat hydrolysis in erythrocytes were 278 nmol/min/mL blood fraction and 628 microM; those in plasma were 160 nmol/min/mL blood fraction and 8890 microM, respectively. Human liver microsomes exhibited a V(max) value of 26.9 nmol/min/mg protein and a K(m) value of 1790 microM. Hydrolytic activity of the erythrocytes and plasma was inhibited by 5, 5'-dithiobis(2-nitrobenzoic acid), an arylesterase inhibitor, in a concentration-dependent manner. In contrast, little or no suppression of these activities was seen with phenylmethylsulfonyl fluoride (PMSF), diisopropyl fluorophosphate (DFP), bis(p-nitrophenyl)phosphate (BNPP), BW284C51 and ethopropazine. The liver microsomal activity was markedly inhibited by PMSF, DFP and BNPP, indicating that carboxylesterase was involved in the nafamostat hydrolysis. Human carboxylesterase 2 expressed in COS-1 cells was capable of hydrolyzing nafamostat at 10 and 100 microM, whereas recombinant carboxylesterase 1 showed significant activity only at a higher substrate concentration (100 microM). The nafamostat hydrolysis in 18 human liver microsomes correlated with aspirin hydrolytic activity specific for carboxylesterase 2 (r=0.815, p<0.01) but not with imidapril hydrolysis catalyzed by carboxylesterase 1 (r=0.156, p=0.54). These results suggest that human arylesterases and carboxylesterase 2 may be predominantly responsible for the metabolism of nafamostat in the blood and liver, respectively.
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Affiliation(s)
- Satoshi Yamaori
- Department of Hygienic Chemistry, Faculty of Pharmaceutical Sciences, Hokuriku University, Kanagawa-machi, Kanazawa, Japan
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Puche E, Perea M. Esterases and anti-tumoral chemotherapy: an interaction of clinical and toxicological interest. Clin Chim Acta 2001; 304:133-6. [PMID: 11165208 DOI: 10.1016/s0009-8981(00)00347-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- E Puche
- Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad de Granada, E-18071 Granada, Spain.
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Tasaki O, Hiraide A, Shiozaki T, Yamamura H, Ninomiya N, Sugimoto H. The dimer and trimer of 3-hydroxybutyrate oligomer as a precursor of ketone bodies for nutritional care. JPEN J Parenter Enteral Nutr 1999; 23:321-5. [PMID: 10574479 DOI: 10.1177/0148607199023006321] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND Ketone bodies have been considered as a means of providing energy because of their good penetration and rapid diffusion in peripheral tissues. However, because the currently available form of 3-hydroxybu-tyrate is the sodium salt, the sodium load is problematic. To avoid it, a mixture of dimer and trimer has been prepared as a precursor of D-3-hydroxybutyrate. The purpose of this study was to investigate whether and how the solution would be converted to monomers. METHODS The plasma concentration of 3-hydroxybutyrate monomer was measured in 10 rats during infusion of dimer and trimer. Stepwise dilutions of the solution were incubated with serum and liver homogenates from five rats, serum samples from five volunteers, and a liver sample from one patient with liver injury. The solution also was incubated with carboxylesterase and triacylglycerol lipase. The concentration of monomer in the medium was measured after incubation. RESULTS The plasma concentration of 3-hydroxybutyrate monomer reached 572 +/- 11 micromol/L 15 minutes after beginning infusion of the mixture at a rate of 25 micromol x kg(-1) x min(-1) and 270 +/- 40 micromol/L at a rate of 12.5 micromol x kg(-1) min(-1). The solution was converted completely to monomers when incubated with rat serum or liver homogenate for 10 minutes. The mixture also was hydrolyzed by human liver homogenate but not by serum. CONCLUSIONS The dimer and trimer of 3-hydroxybutyrate can be converted rapidly to monomer in rat and human tissues. 3-Hydroxybutyrate oligomers could be an energy substrate for injured patients.
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Affiliation(s)
- O Tasaki
- Hanwa Memorial Hospital, Osaka City, Osaka, Japan
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Leng G, Lewalter J, Röhrig B, Idel H. The influence of individual susceptibility in pyrethroid exposure. Toxicol Lett 1999; 107:123-30. [PMID: 10414789 DOI: 10.1016/s0378-4274(99)00039-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The aim of this study was to find a suitable biomarker for pyrethroid adverse effects. It was shown that there is a correlation between the half-life time (t(1/2)) of pyrethroids in plasma and the clinical findings. We hypothized that this finding indicates an interindividual different amount of total esterase activity or even a polymorphism. By in vitro experiments it was demonstrated that pyrethroids are cleaved by carboxylesterases. After it turned out that carboxylesterase activity in human plasma is too low for detection, a method for specific determination of carboxylesterase activity in human isolated lymphocytes was developed. As a substrate for carboxylesterase activity, cyfluthrin was added to the lymphocyte suspension. As a proof for cyfluthrin degradation by carboxylesterases the produced hydrocyanic acid was determined by GC/MS. First hints for interindividual differences in carboxylesterase activity in lymphocytes were found.
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Affiliation(s)
- G Leng
- Institute of Hygiene, Heinrich-Heine-University Düsseldorf, FRG.
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Abstract
Multiple carboxylesterases (EC 3.1.1.1) play an important role in the hydrolytic biotransformation of a vast number of structurally diverse drugs. These enzymes are major determinants of the pharmacokinetic behavior of most therapeutic agents containing ester or amide bonds. Carboxylesterase activity can be influenced by interactions of a variety of compounds either directly or at the level of enzyme regulation. Since a significant number of drugs are metabolized by carboxylesterase, altering the activity of this enzyme class has important clinical implications. Drug elimination decreases and the incidence of drug-drug interactions increases when two or more drugs compete for hydrolysis by the same carboxylesterase isozyme. Exposure to environmental pollutants or to lipophilic drugs can result in induction of carboxylesterase activity. Therefore, the use of drugs known to increase the microsomal expression of a particular carboxylesterase, and thus to increase associated drug hydrolysis capacity in humans, requires caution. Mammalian carboxylesterases represent a multigene family, the products of which are localized in the endoplasmic reticulum of many tissues. A comparison of the nucleotide and amino acid sequence of the mammalian carboxylesterases shows that all forms expressed in the rat can be assigned to one of three gene subfamilies with structural identities of more than 70% within each subfamily. Considerable confusion exists in the scientific community in regards to a systematic nomenclature and classification of mammalian carboxylesterase. Until recently, adequate sequence information has not been available such that valid links among the mammalian carboxylesterase gene family or evolutionary relationships could be established. However, sufficient basic data are now available to support such a novel classification system.
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Affiliation(s)
- T Satoh
- Laboratory of Biochemical Pharmacology and Toxicology, Faculty of Pharmaceutical Sciences, Chiba University, Japan.
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Mantle D, Saleem MA, Williams FM, Wilkins RM, Shakoori AR. Effect of pirimiphos-methyl on proteolytic enzyme activities in rat heart, kidney, brain and liver tissues in vivo. Clin Chim Acta 1997; 262:89-97. [PMID: 9204212 DOI: 10.1016/s0009-8981(97)06541-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
To elucidate whether pesticide toxicity in higher animals involves pesticide-induced dysfunction of the intracellular protein catabolic process, we have determined the effect in vivo of the organophosphate insecticide pirimiphos-methyl on the activities of representative protein catabolising cytoplasmic and lysosomal proteases (responsible for the various stages of the protein degradation cascade and essential for normal cell functioning) in heart, kidney, brain and liver target tissues in the rat. In liver tissue (the major site of pesticide metabolism), the activities of all of the cytoplasmic proteases investigated (alanyl-, arginyl-, leucyl aminopeptidases, dipeptidyl aminopeptidase IV, tripeptidyl aminopeptidase, proline endopeptidase) were significantly inhibited (by 20-40% of control activity) following administration of 10 mg pirimiphos-methyl/kg bodyweight, whereas of the lysosomal proteases investigated, only the activities of dipeptidyl aminopeptidase I and cathepsin D were significantly reduced (by 15-20% of control activity). In contrast, there was no insecticide-induced inhibition of protease activities in heart, kidney or brain tissues; some lysosomal enzymes (dipeptidyl aminopeptidase I, cathepsins L and D) showed significantly increased activities in these tissues (the reason for which remains to be determined). We conclude that the effect of pirimiphos-methyl on proteolytic enzyme activities differs in different target tissues, and that pirimiphos-methyl induced inhibition of proteases in liver tissue may represent a previously unrecognised toxicity hazard in higher animals.
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Affiliation(s)
- D Mantle
- Department of Neurochemistry, Newcastle General Hospital, Newcastle upon Tyne, UK
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Williams FM. Exposure factors that contribute to variability in toxic responses in man. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 1996; 2:147-149. [PMID: 21781717 DOI: 10.1016/s1382-6689(96)00045-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The route of exposure is an important determinant of the internal dose of a chemical in man and the expression of toxicity. Routes of exposure are inhalation via the lung and dermal penetration, and the degree of absorption and first pass metabolism vary between chemicals. Inter-individual differences in metabolism of both genetic and environmental cause contribute to variability in metabolic fate and toxic response.
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Hou X, Maser RL, Magenheimer BS, Calvet JP. A mouse kidney- and liver-expressed cDNA having homology with a prokaryotic parathion hydrolase (phosphotriesterase)-encoding gene: abnormal expression in injured and polycystic kidneys. Gene 1996; 168:157-63. [PMID: 8654936 DOI: 10.1016/0378-1119(95)00746-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
To investigate abnormalities in gene expression associated with cyst formation in polycystic kidney disease, differential cDNA library screening was carried out using RNA from normal and cystic kidneys of the C57BL/6J-cpk mouse. Among a number of genes found to be abnormally expressed was one (cDNA clone 56-1) that was significantly underexpressed in cystic kidneys. Hybridization analyses revealed that the 56-1 mRNA is expressed primarily in kidney and liver, and that the kidney expression begins postnatally and continues in the adult. Expression of this mRNA was found to be significantly decreased upon acute renal injury induced by a single intraperitoneal injection of folic acid, and to return to normal levels upon recovery of kidney function. Analysis of the cDNA sequence predicted a protein of 349 amino acids (aa), which was confirmed by in vitro translation of a sense-strand transcript, producing a protein of approx. 39 kDa. The aa sequence shows similarity to Flavobacterium sp. and Pseudomonas diminuta parathion hydrolase (phosphotriesterase or PTE), an enzyme that hydrolyzes toxic organophosphates and other phosphotriesters, and to the predicted product of an Escherichia coli open reading frame of unknown function (phosphotriesterase homology protein or PHP). Use of optimal alignment programs demonstrated a significant overall homology between the bacterial and mouse sequences, with greater than 50% aa sequence similarity. This cDNA represents the first eukaryotic sequence showing similarity to these prokaryotic genes. Based on this apparent homology, it has been named mpr56-1 (for mouse phosphotriesterase-related 56-1).
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Affiliation(s)
- X Hou
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City 66160-7421, USA
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