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Solidoro R, Miciaccia M, Bonaccorso C, Fortuna CG, Armenise D, Centonze A, Ferorelli S, Vitale P, Rodrigues P, Guimarães R, de Oliveira A, da Paz M, Rangel L, Sathler PC, Altomare A, Perrone MG, Scilimati A. A further pocket or conformational plasticity by mapping COX-1 catalytic site through modified-mofezolac structure-inhibitory activity relationships and their antiplatelet behavior. Eur J Med Chem 2024; 266:116135. [PMID: 38219659 DOI: 10.1016/j.ejmech.2024.116135] [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: 09/15/2023] [Revised: 01/04/2024] [Accepted: 01/08/2024] [Indexed: 01/16/2024]
Abstract
Cyclooxygenase enzymes have distinct roles in cardiovascular, neurological, and neurodegenerative disease. They are differently expressed in different type of cancers. Specific and selective COXs inhibitors are needed to be used alone or in combo-therapies. Fully understand the differences at the catalytic site of the two cyclooxygenase (COX) isoforms is still opened to investigation. Thus, two series of novel compounds were designed and synthesized in fair to good yields using the highly selective COX-1 inhibitor mofezolac as the lead compound to explore a COX-1 zone formed by the polar residues Q192, S353, H90 and Y355, as well as hydrophobic amino acids I523, F518 and L352. According to the structure of the COX-1:mofezolac complex, hydrophobic amino acids appear to have free volume eventually accessible to the more sterically hindering groups than the methoxy linked to the phenyl groups of mofezolac, in particular the methoxyphenyl at C4-mofezolac isoxazole. Mofezolac bears two methoxyphenyl groups linked to C3 and C4 of the isoxazole core ring. Thus, in the novel compounds, one or both methoxy groups were replaced by the higher homologous ethoxy, normal and isopropyl, normal and tertiary butyl, and phenyl and benzyl. Furthermore, a major difference between the two sets of compounds is the presence of either a methyl or acetic moiety at the C5 of the isoxazole. Among the C5-methyl series, 12 (direct precursor of mofezolac) (COX-1 IC50 = 0.076 μM and COX-2 IC50 = 0.35 μM) and 15a (ethoxy replacing the two methoxy groups in 12; COX-1 IC50 = 0.23 μM and COX-2 IC50 > 50 μM) were still active and with a Selectivity Index (SI = COX-2 IC50/COX-1 IC50) = 5 and 217, respectively. The other symmetrically substituted alkoxyphenyl moietis were inactive at 50 μM final concentration. Among the asymmetrically substituted, only the 16a (methoxyphenyl on C3-isoxazole and ethoxyphenyl on C4-isoxazole) and 16b (methoxyphenyl on C3-isoxazole and n-propoxyphenyl on C4-isoxazole) were active with SI = 1087 and 38, respectively. Among the set of compounds with the acetic moiety, structurally more similar to mofezolac (SI = 6329), SI ranged between 1.4 and 943. It is noteworthy that 17b (n-propoxyphenyl on both C3- and C4-isoxazole) were found to be a COX-2 slightly selective inhibitor with SI = 0.072 (COX-1 IC50 > 50 μM and COX-2 IC50 = 3.6 μM). Platelet aggregation induced by arachidonic acid (AA) can be in vitro suppressed by the synthesized compounds, without affecting of the secondary hemostasia, confirming the biological effect provided by the selective inhibition of COX-1. A positive profile of hemocompatibility in relation to erythrocyte and platelet toxicity was observed. Additionally, these compounds exhibited a positive profile of hemocompatibility and reduced cytotoxicity. Quantitative structure activity relationship (QSAR) models and molecular modelling (Ligand and Structure based virtual screening procedures) provide key information on the physicochemical and pharmacokinetic properties of the COX-1 inhibitors as well as new insights into the mechanisms of inhibition that will be used to guide the development of more effective and selective compounds. X-ray analysis was used to confirm the chemical structure of 14 (MSA17).
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Affiliation(s)
- Roberta Solidoro
- Research Laboratory for Woman and Child Health, Department of Pharmacy - Pharmaceutical Sciences, University of Bari "Aldo Moro", Via E. Orabona 4, 70125, Bari, Italy
| | - Morena Miciaccia
- Research Laboratory for Woman and Child Health, Department of Pharmacy - Pharmaceutical Sciences, University of Bari "Aldo Moro", Via E. Orabona 4, 70125, Bari, Italy
| | - Carmela Bonaccorso
- Laboratory of Molecular Modelling and Heterocyclic Compounds ModHet, Department of Chemical Sciences, University of Catania, Viale Andrea Doria 6, 95125, Catania, Italy
| | - Cosimo Gianluca Fortuna
- Laboratory of Molecular Modelling and Heterocyclic Compounds ModHet, Department of Chemical Sciences, University of Catania, Viale Andrea Doria 6, 95125, Catania, Italy
| | - Domenico Armenise
- Research Laboratory for Woman and Child Health, Department of Pharmacy - Pharmaceutical Sciences, University of Bari "Aldo Moro", Via E. Orabona 4, 70125, Bari, Italy
| | - Antonella Centonze
- Research Laboratory for Woman and Child Health, Department of Pharmacy - Pharmaceutical Sciences, University of Bari "Aldo Moro", Via E. Orabona 4, 70125, Bari, Italy
| | - Savina Ferorelli
- Research Laboratory for Woman and Child Health, Department of Pharmacy - Pharmaceutical Sciences, University of Bari "Aldo Moro", Via E. Orabona 4, 70125, Bari, Italy
| | - Paola Vitale
- Research Laboratory for Woman and Child Health, Department of Pharmacy - Pharmaceutical Sciences, University of Bari "Aldo Moro", Via E. Orabona 4, 70125, Bari, Italy
| | - Pryscila Rodrigues
- Laboratory of Experimental Hemostasis, Carlos Chagas Filho Avenue, 373, 21941599, Rio de Janeiro, Brazil
| | - Renilda Guimarães
- Laboratory of Experimental Hemostasis, Carlos Chagas Filho Avenue, 373, 21941599, Rio de Janeiro, Brazil
| | - Alana de Oliveira
- Laboratory of Experimental Hemostasis, Carlos Chagas Filho Avenue, 373, 21941599, Rio de Janeiro, Brazil
| | - Mariana da Paz
- Laboratory of Tumoral Biochemistry, Faculty of Pharmacy, Federal University of Rio de Janeiro, Carlos Chagas Filho Avenue, 373, 21941599, Rio de Janeiro, Brazil
| | - Luciana Rangel
- Laboratory of Tumoral Biochemistry, Faculty of Pharmacy, Federal University of Rio de Janeiro, Carlos Chagas Filho Avenue, 373, 21941599, Rio de Janeiro, Brazil
| | - Plínio Cunha Sathler
- Laboratory of Experimental Hemostasis, Carlos Chagas Filho Avenue, 373, 21941599, Rio de Janeiro, Brazil
| | - Angela Altomare
- Institute of Crystallography-CNR, Via Amendola 122/o, 70126, Bari, Italy
| | - Maria Grazia Perrone
- Research Laboratory for Woman and Child Health, Department of Pharmacy - Pharmaceutical Sciences, University of Bari "Aldo Moro", Via E. Orabona 4, 70125, Bari, Italy.
| | - Antonio Scilimati
- Research Laboratory for Woman and Child Health, Department of Pharmacy - Pharmaceutical Sciences, University of Bari "Aldo Moro", Via E. Orabona 4, 70125, Bari, Italy.
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2
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Dong L, Malkowski MG. Defining the Conformational Ensembles Associated with Ligand Binding to Cyclooxygenase-2. Biochemistry 2023; 62:3134-3144. [PMID: 37852627 DOI: 10.1021/acs.biochem.3c00341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2023]
Abstract
Cyclooxygenases (COX) catalyze the committed step in the production of prostaglandins responsible for the maintenance of physiological homeostasis. While crystal structures of COX in complex with substrates and inhibitors have provided insight into the molecular interactions governing their binding, they have not uncovered specific details related to the protein conformational motions responsible for important aspects of the COX function. We created a cysteine-free COX-2 construct and introduced a free cysteine at position-122 to enable labeling with 3-bromo-1,1,1-trifluoroacetone (BTFA). Placement of the label adjacent to the cyclooxygenase channel entrance permitted the detection of alterations upon ligand binding. 19F-nuclear magnetic resonance spectroscopy (19F-NMR) was then used to probe the conformational ensembles arising from BTFA-labeled COX-2 constructs in the presence and absence of ligands known to allosterically activate or inhibit COX-2. 19F-NMR analyses performed in the presence of the time-dependent inhibitor flurbiprofen, as well as Arg-120, Tyr-355, and Glu-524 mutations, led to the classification of two ensembles as representing the relaxed and tightened states of the cyclooxygenase channel entrance. A third ensemble, generated in the presence of arachidonic acid and the Y355F mutant and modulated by the allosteric potentiators palmitic acid and oleic acid and the nonallosteric substrates 2-arachidonoyl glycerol ether and anandamide, was classified as being related to the allosteric regulation of COX activity. The ensemble-based insight into COX function demonstrated here complements the static information derived from crystal structure analyses, collectively providing a more detailed framework of the dynamics involved in the regulation of COX catalysis and inhibition.
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Affiliation(s)
- Liang Dong
- Department of Structural Biology, Jacobs School of Medicine and Biomedical Sciences, University of Buffalo, the State University of New York, Buffalo, New York 14203, United States
| | - Michael G Malkowski
- Department of Structural Biology, Jacobs School of Medicine and Biomedical Sciences, University of Buffalo, the State University of New York, Buffalo, New York 14203, United States
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3
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Romero-Estrada A, Boto A, González-Christen J, Romero-Estudillo I, Garduño-Ramírez ML, Razo-Hernández RS, Marquina S, Maldonado-Magaña A, Columba-Palomares MC, Sánchez-Carranza JN, Alvarez L. Synthesis, Biological Evaluation, and Molecular Docking Study of 3-Amino and 3-Hydroxy- seco A Derivatives of α-Amyrin and 3-Epilupeol as Inhibitors of COX-2 Activity and NF-kB Activation. JOURNAL OF NATURAL PRODUCTS 2022; 85:787-803. [PMID: 35175765 DOI: 10.1021/acs.jnatprod.1c00827] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
In this study, a series of novel 3-seco-A derivatives of the natural triterpenes α-amyrin (1) and 3-epilupeol (2) were synthesized by a one-pot radical scission-oxidation procedure and evaluated in vitro and in vivo for their capacity to inhibit the inflammatory process. For the in vitro studies, the trans-4-hydroxy-l-proline methyl ester derivatives (1f and 2f) were consistently effective in inhibiting NO, IL-6, and TNF-α secretion, as well as inhibition of NF-κB activation, in RAW cells stimulated by LPS. The further in vivo anti-inflammatory study revealed that the trans-4-hydroxy-l-proline methyl ester derivatives (1f and 2f), together with 1g, were the most effective in inhibiting TPA-induced edema. Interestingly, the α-amyrin derivatives were the most potent inhibitors of COX-2, but inhibited COX-1 only to some extent. The hydroxyl derivative (1c) was selective for COX-2 inhibition (66.3 ± 1.1% at 17.5 μM) without affecting the COX-1 isoform and did not present toxicity. Molecular docking studies revealed that these compounds bind with their polar region in the cavity over Arg-120, and their lipophilic part is orientated to the HEM cofactor similarly to the natural substrate arachidonic acid in the catalytic site of COX-2. These results indicated that seco-A ursane derivatives could be considered promising candidates for the future development of selective NF-κB and COX-2 inhibitors.
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Affiliation(s)
- Antonio Romero-Estrada
- Centro de Investigaciones Químicas-IICBA, Universidad Autónoma del Estado de Morelos, Avenida Universidad 1001, Col. Chamilpa, Cuernavaca 62209, Morelos, México
- Departamento de Madera, Celulosa y Papel, Centro Universitario de Ciencias Exactas e Ingenierías, Universidad de Guadalajara, Km 15.5 Carretera Guadalajara-Nogales, Col. Las Agujas, Zapopan 45100, Jalisco, México
| | - Alicia Boto
- Instituto de Productos Naturales y Agrobiología del CSIC, Avenuda Astrofísico Francisco Sánchez 3, 38206-La Laguna, Tenerife, Spain
| | - Judith González-Christen
- Facultad de Farmacia, Universidad Autónoma del Estado de Morelos, Avenida Universidad 1001, Col. Chamilpa, Cuernavaca 62209 Morelos, México
| | - Ivan Romero-Estudillo
- Centro de Investigaciones Químicas-IICBA, Universidad Autónoma del Estado de Morelos, Avenida Universidad 1001, Col. Chamilpa, Cuernavaca 62209, Morelos, México
- CONACYT-Centro de Investigaciones Químicas-IICBA, Universidad Autónoma del Estado de Morelos, Avenida Universidad 1001, Col. Chamilpa, Cuernavaca 62209 Morelos, México
| | - María Luisa Garduño-Ramírez
- Centro de Investigaciones Químicas-IICBA, Universidad Autónoma del Estado de Morelos, Avenida Universidad 1001, Col. Chamilpa, Cuernavaca 62209, Morelos, México
| | - Rodrigo Said Razo-Hernández
- Centro de Investigación en Dinámica Celular-IICBA, Universidad Autónoma del Estado de Morelos, Avenida Universidad 1001, Col. Chamilpa, Cuernavaca 62209, Morelos, México
| | - Silvia Marquina
- Centro de Investigaciones Químicas-IICBA, Universidad Autónoma del Estado de Morelos, Avenida Universidad 1001, Col. Chamilpa, Cuernavaca 62209, Morelos, México
| | - Amalia Maldonado-Magaña
- Instituto Tecnológico de Milpa Alta. Independencia Sur No. 36, Col. San Salvador Cuauhténco, Alcaldía Milpa Alta CDMX 12300, México
| | - María C Columba-Palomares
- Facultad de Farmacia, Universidad Autónoma del Estado de Morelos, Avenida Universidad 1001, Col. Chamilpa, Cuernavaca 62209 Morelos, México
| | - Jessica Nayelli Sánchez-Carranza
- Facultad de Farmacia, Universidad Autónoma del Estado de Morelos, Avenida Universidad 1001, Col. Chamilpa, Cuernavaca 62209 Morelos, México
| | - Laura Alvarez
- Centro de Investigaciones Químicas-IICBA, Universidad Autónoma del Estado de Morelos, Avenida Universidad 1001, Col. Chamilpa, Cuernavaca 62209, Morelos, México
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Friedrich L, Cingolani G, Ko Y, Iaselli M, Miciaccia M, Perrone MG, Neukirch K, Bobinger V, Merk D, Hofstetter RK, Werz O, Koeberle A, Scilimati A, Schneider G. Learning from Nature: From a Marine Natural Product to Synthetic Cyclooxygenase-1 Inhibitors by Automated De Novo Design. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:e2100832. [PMID: 34176236 PMCID: PMC8373093 DOI: 10.1002/advs.202100832] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 05/16/2021] [Indexed: 05/03/2023]
Abstract
The repertoire of natural products offers tremendous opportunities for chemical biology and drug discovery. Natural product-inspired synthetic molecules represent an ecologically and economically sustainable alternative to the direct utilization of natural products. De novo design with machine intelligence bridges the gap between the worlds of bioactive natural products and synthetic molecules. On employing the compound Marinopyrrole A from marine Streptomyces as a design template, the algorithm constructs innovative small molecules that can be synthesized in three steps, following the computationally suggested synthesis route. Computational activity prediction reveals cyclooxygenase (COX) as a putative target of both Marinopyrrole A and the de novo designs. The molecular designs are experimentally confirmed as selective COX-1 inhibitors with nanomolar potency. X-ray structure analysis reveals the binding of the most selective compound to COX-1. This molecular design approach provides a blueprint for natural product-inspired hit and lead identification for drug discovery with machine intelligence.
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Affiliation(s)
- Lukas Friedrich
- Department of Chemistry and Applied BiosciencesETH ZurichVladimir‐Prelog‐Weg 4Zurich8093Switzerland
| | - Gino Cingolani
- Department of Biochemistry and Molecular BiologySidney Kimmel Cancer CenterThomas Jefferson University1020 Locust StreetPhiladelphiaPA19107USA
| | - Ying‐Hui Ko
- Department of Biochemistry and Molecular BiologySidney Kimmel Cancer CenterThomas Jefferson University1020 Locust StreetPhiladelphiaPA19107USA
| | - Mariaclara Iaselli
- Department of Pharmacy – Pharmaceutical SciencesUniversity of BariVia E. Orabona 4Bari70125Italy
| | - Morena Miciaccia
- Department of Pharmacy – Pharmaceutical SciencesUniversity of BariVia E. Orabona 4Bari70125Italy
| | - Maria Grazia Perrone
- Department of Pharmacy – Pharmaceutical SciencesUniversity of BariVia E. Orabona 4Bari70125Italy
| | - Konstantin Neukirch
- Michael Popp Institute and Center for Molecular Biosciences Innsbruck (CMBI)University of InnsbruckInnsbruck6020Austria
| | - Veronika Bobinger
- Department of Chemistry and Applied BiosciencesETH ZurichVladimir‐Prelog‐Weg 4Zurich8093Switzerland
| | - Daniel Merk
- Department of Chemistry and Applied BiosciencesETH ZurichVladimir‐Prelog‐Weg 4Zurich8093Switzerland
- Institute of Pharmaceutical ChemistryGoethe‐UniversityMax‐von‐Laue Straße 9Frankfurt am Main60438Germany
| | - Robert Klaus Hofstetter
- Department of Pharmaceutical/Medicinal ChemistryFriedrich‐Schiller‐University JenaPhilosophenweg 14Jena07743Germany
| | - Oliver Werz
- Department of Pharmaceutical/Medicinal ChemistryFriedrich‐Schiller‐University JenaPhilosophenweg 14Jena07743Germany
| | - Andreas Koeberle
- Michael Popp Institute and Center for Molecular Biosciences Innsbruck (CMBI)University of InnsbruckInnsbruck6020Austria
| | - Antonio Scilimati
- Department of Pharmacy – Pharmaceutical SciencesUniversity of BariVia E. Orabona 4Bari70125Italy
| | - Gisbert Schneider
- Department of Chemistry and Applied BiosciencesETH ZurichVladimir‐Prelog‐Weg 4Zurich8093Switzerland
- ETH Singapore SEC Ltd1 CREATE Way, #06‐01 CREATE TowerSingapore138602Singapore
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5
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Uddin MJ, Xu S, Crews BC, Aleem AM, Ghebreselasie K, Banerjee S, Marnett LJ. Harmaline Analogs as Substrate-Selective Cyclooxygenase-2 Inhibitors. ACS Med Chem Lett 2020; 11:1881-1885. [PMID: 33062168 DOI: 10.1021/acsmedchemlett.9b00555] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 02/14/2020] [Indexed: 11/28/2022] Open
Abstract
We report the design, synthesis, and evaluation of a series of harmaline analogs as selective inhibitors of 2-arachidonylglycerol (2-AG) oxygenation over arachidonic acid (AA) oxygenation by purified cyclooxygenase-2 (COX-2). A fused tricyclic harmaline analog containing a CH3O substituent at C-6 and a CH3 group at the C-1 position of 4,9-dihydro-3H-pyrido[3,4-b]indole (compound 3) was the best substrate-selective COX-2 inhibitor of those evaluated, exhibiting a 2AG-selective COX-2 inhibitory IC50 of 0.022 μM as compared to >1 μM for AA. The 2.66 Å resolution crystal complex of COX-2 with compound 3 revealed that this series of tricyclic indoles binds in the cyclooxygenase channel by flipping the side chain of L531 toward the dimer interface. This novel tricyclic indole series provides the foundation for the development of promising substrate-selective molecules capable of increasing endocannabinoid (EC) levels in the brain to offer new treatments for a variety of diseases, from pain and inflammation to stress and anxiety disorders.
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Affiliation(s)
- Md. Jashim Uddin
- A. B. Hancock, Jr., Memorial Laboratory for Cancer Research, Departments of Biochemistry, Chemistry, and Pharmacology, Vanderbilt Institute of Chemical Biology, and Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - Shu Xu
- A. B. Hancock, Jr., Memorial Laboratory for Cancer Research, Departments of Biochemistry, Chemistry, and Pharmacology, Vanderbilt Institute of Chemical Biology, and Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - Brenda C. Crews
- A. B. Hancock, Jr., Memorial Laboratory for Cancer Research, Departments of Biochemistry, Chemistry, and Pharmacology, Vanderbilt Institute of Chemical Biology, and Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - Ansari M. Aleem
- A. B. Hancock, Jr., Memorial Laboratory for Cancer Research, Departments of Biochemistry, Chemistry, and Pharmacology, Vanderbilt Institute of Chemical Biology, and Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - Kebreab Ghebreselasie
- A. B. Hancock, Jr., Memorial Laboratory for Cancer Research, Departments of Biochemistry, Chemistry, and Pharmacology, Vanderbilt Institute of Chemical Biology, and Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - Surajit Banerjee
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
- Northeastern Collaborative Access Team, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Lawrence J. Marnett
- A. B. Hancock, Jr., Memorial Laboratory for Cancer Research, Departments of Biochemistry, Chemistry, and Pharmacology, Vanderbilt Institute of Chemical Biology, and Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
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Rouzer CA, Marnett LJ. Structural and Chemical Biology of the Interaction of Cyclooxygenase with Substrates and Non-Steroidal Anti-Inflammatory Drugs. Chem Rev 2020; 120:7592-7641. [PMID: 32609495 PMCID: PMC8253488 DOI: 10.1021/acs.chemrev.0c00215] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cyclooxgenases are key enzymes of lipid signaling. They carry out the first step in the production of prostaglandins, important mediators of inflammation, pain, cardiovascular disease, and cancer, and they are the molecular targets for nonsteroidal anti-inflammatory drugs, which are among the oldest and most chemically diverse set of drugs known. Homodimeric proteins that behave as allosterically modulated, functional heterodimers, the cyclooxygenases exhibit complex kinetic behavior, requiring peroxide-dependent activation and undergoing suicide inactivation. Due to their important physiological and pathophysiological roles and keen interest on the part of the pharmaceutical industry, the cyclooxygenases have been the focus of a vast array of structural studies, leading to the publication of over 80 crystal structures of the enzymes in complex with substrates or inhibitors supported by a wealth of functional data generated by site-directed mutation experiments. In this review, we explore the chemical biology of the cyclooxygenases through the lens of this wealth of structural and functional information. We identify key structural features of the cyclooxygenases, break down their active site into regional binding pockets to facilitate comparisons between structures, and explore similarities and differences in the binding modes of the wide variety of ligands (both substrates and inhibitors) that have been characterized in complex with the enzymes. Throughout, we correlate structure with function whenever possible. Finally, we summarize what can and cannot be learned from the currently available structural data and discuss the critical intriguing questions that remain despite the wealth of information that has been amassed in this field.
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Affiliation(s)
- Carol A Rouzer
- A. B. Hancock Jr. Memorial Laboratory for Cancer Research, Departments of Biochemistry, Chemistry, and Pharmacology, Vanderbilt Institute of Chemical Biology, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - Lawrence J Marnett
- A. B. Hancock Jr. Memorial Laboratory for Cancer Research, Departments of Biochemistry, Chemistry, and Pharmacology, Vanderbilt Institute of Chemical Biology, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
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7
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Hajeyah AA, Griffiths WJ, Wang Y, Finch AJ, O’Donnell VB. The Biosynthesis of Enzymatically Oxidized Lipids. Front Endocrinol (Lausanne) 2020; 11:591819. [PMID: 33329396 PMCID: PMC7711093 DOI: 10.3389/fendo.2020.591819] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 10/26/2020] [Indexed: 12/14/2022] Open
Abstract
Enzymatically oxidized lipids are a specific group of biomolecules that function as key signaling mediators and hormones, regulating various cellular and physiological processes from metabolism and cell death to inflammation and the immune response. They are broadly categorized as either polyunsaturated fatty acid (PUFA) containing (free acid oxygenated PUFA "oxylipins", endocannabinoids, oxidized phospholipids) or cholesterol derivatives (oxysterols, steroid hormones, and bile acids). Their biosynthesis is accomplished by families of enzymes that include lipoxygenases (LOX), cyclooxygenases (COX), cytochrome P450s (CYP), and aldo-keto reductases (AKR). In contrast, non-enzymatically oxidized lipids are produced by uncontrolled oxidation and are broadly considered to be harmful. Here, we provide an overview of the biochemistry and enzymology of LOXs, COXs, CYPs, and AKRs in humans. Next, we present biosynthetic pathways for oxylipins, oxidized phospholipids, oxysterols, bile acids and steroid hormones. Last, we address gaps in knowledge and suggest directions for future work.
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Affiliation(s)
- Ali A. Hajeyah
- Systems Immunity Research Institute and Division of Infection and Immunity, Cardiff University, Cardiff, United Kingdom
- *Correspondence: Ali A. Hajeyah,
| | - William J. Griffiths
- Institute of Life Science, Swansea University Medical School, Swansea, United Kingdom
| | - Yuqin Wang
- Institute of Life Science, Swansea University Medical School, Swansea, United Kingdom
| | - Andrew J. Finch
- Centre for Tumour Biology, Barts Cancer Institute, Queen Mary University of London, London, United Kingdom
| | - Valerie B. O’Donnell
- Systems Immunity Research Institute and Division of Infection and Immunity, Cardiff University, Cardiff, United Kingdom
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8
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Dong L, Anderson AJ, Malkowski MG. Arg-513 and Leu-531 Are Key Residues Governing Time-Dependent Inhibition of Cyclooxygenase-2 by Aspirin and Celebrex. Biochemistry 2019; 58:3990-4002. [PMID: 31469551 DOI: 10.1021/acs.biochem.9b00659] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Aspirin and Celebrex are well-known time-dependent inhibitors of the cyclooxygenases (COX). Molecular dynamics simulations suggest that Arg-513 and Leu-531 contribute to the structural mechanisms of COX inhibition. We used mutagenesis and functional analyses to characterize how substitutions at these positions influence time-dependent inhibition by aspirin and Celebrex. We show that substitutions of Leu-531 with asparagine and phenylalanine significantly attenuate time-dependent inhibition of COX-2 by these drugs. The introduction of side chain bulk, rigidity, and charge would disrupt the formation of the initial noncovalent complex, in the case of aspirin, and the "high-affinity" binding state, in the case of Celebrex. Substitution of Arg-513 with histidine (the equivalent residue in COX-1) resulted in a 2-fold potentiation of aspirin inhibition, in support of the hypothesis that the presence of histidine in COX-1 lowers the activation barrier associated with the formation of the initial noncovalent enzyme-inhibitor complex. As a corollary, we previously hypothesized that the flexibility associated with Leu-531 contributes to the binding of arachidonic acid (AA) to acetylated COX-2 to generate 15R-hydroxyeicosatetraenoic acid (15R-HETE). We determined the X-ray crystal structure of AA bound to Co3+-protoporphyrin IX-reconstituted V349I murine COX-2 (muCOX-2). V349I muCOX-2 was utilized as a surrogate to trap AA in a conformation leading to 15R-HETE. AA binds in a C-shaped pose, facilitated by the rotation of the Leu-531 side chain. Ile-349 is positioned to sterically shield antarafacial oxygen addition at carbon-15 in a manner similar to that proposed for the acetylated Ser-530 side chain.
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Affiliation(s)
- Liang Dong
- Department of Structural Biology, Jacobs School of Medicine and Biomedical Sciences , University of Buffalo, the State University of New York , Buffalo , New York 14203 , United States
| | - Alyssa J Anderson
- Department of Structural Biology, Jacobs School of Medicine and Biomedical Sciences , University of Buffalo, the State University of New York , Buffalo , New York 14203 , United States
| | - Michael G Malkowski
- Department of Structural Biology, Jacobs School of Medicine and Biomedical Sciences , University of Buffalo, the State University of New York , Buffalo , New York 14203 , United States
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9
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Smith WL, Malkowski MG. Interactions of fatty acids, nonsteroidal anti-inflammatory drugs, and coxibs with the catalytic and allosteric subunits of cyclooxygenases-1 and -2. J Biol Chem 2019; 294:1697-1705. [PMID: 30710016 DOI: 10.1074/jbc.tm118.006295] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Prostaglandin endoperoxide H synthases-1 and -2, commonly called cyclooxygenases-1 and -2 (COX-1 and -2), catalyze the committed step in prostaglandin biosynthesis-the conversion of arachidonic acid to prostaglandin endoperoxide H2 Both COX isoforms are sequence homodimers that function as conformational heterodimers having allosteric (Eallo) and catalytic (Ecat) subunits. At least in the case of COX-2, the enzyme becomes folded into a stable Eallo/Ecat pair. Some COX inhibitors (i.e. nonsteroidal anti-inflammatory drugs and coxibs) and common fatty acids (FAs) modulate Ecat activity by binding Eallo. However, the interactions and outcomes often differ between isoforms. For example, naproxen directly and completely inhibits COX-1 by binding Ecat but indirectly and incompletely inhibits COX-2 by binding Eallo. Additionally, COX-1 is allosterically inhibited up to 50% by common FAs like palmitic acid, whereas COX-2 is allosterically activated 2-fold by palmitic acid. FA binding to Eallo also affects responses to COX inhibitors. Thus, COXs are physiologically and pharmacologically regulated by the FA tone of the milieu in which each operates-COX-1 in the endoplasmic reticulum and COX-2 in the Golgi apparatus. Cross-talk between Eallo and Ecat involves a loop in Eallo immediately downstream of Arg-120. Mutational studies suggest that allosteric modulation requires a direct interaction between the carboxyl group of allosteric effectors and Arg-120 of Eallo; however, structural studies show some allosterically active FAs positioned in COX-2 in a conformation lacking an interaction with Arg-120. Thus, many details about the biological consequences of COX allosterism and how ligand binding to Eallo modulates Ecat remain to be resolved.
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Affiliation(s)
- William L Smith
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109.
| | - Michael G Malkowski
- Department of Structural Biology, Jacobs School of Medicine and Biomedical Sciences, University of Buffalo, Buffalo, New York 14203.
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10
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Mohamed MS, Mansour YE, Amin HK, El-Araby ME. Molecular modelling insights into a physiologically favourable approach to eicosanoid biosynthesis inhibition through novel thieno[2,3-b]pyridine derivatives. J Enzyme Inhib Med Chem 2018; 33:755-767. [PMID: 29651867 PMCID: PMC6009894 DOI: 10.1080/14756366.2018.1457657] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
In this research, we exploited derivatives of thieno[2,3-b]pyridine as dual inhibitors of the key enzymes in eicosanoid biosynthesis, cyclooxygenase (COX, subtypes 1 and 2) and 5-lipoxygensase (5-LOX). Testing these compounds in a rat paw oedema model revealed potency higher than ibuprofen. The most active compounds 7a, 7b, 8b, and 8c were screened against COX-1/2 and 5-LOX enzymes. Compound 7a was the most powerful inhibitor of 5-LOX with IC50 = 0.15 µM, while its p-chloro analogue 7b was more active against COX-2 (IC50 = 7.5 µM). The less desirable target COX-1 was inhibited more potently by 8c with IC50 = 7.7 µM. Surflex docking programme predicted that the more stable anti- conformer of compound (7a) formed a favourable complex with the active site of 5-LOX but not COX-1. This is in contrast to the binding mode of 8c, which resembles the syn-conformer of series 7 and binds favourably to COX-1.
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Affiliation(s)
- Mosaad S Mohamed
- a Department of Pharmaceutical Organic Chemistry , Faculty of Pharmacy, Helwan University , Cairo , Egypt
| | - Yara E Mansour
- a Department of Pharmaceutical Organic Chemistry , Faculty of Pharmacy, Helwan University , Cairo , Egypt
| | - Hatem K Amin
- b Department of Biochemistry and Molecular Biology , Faculty of Pharmacy, Helwan University , Cairo , Egypt
| | - Moustafa E El-Araby
- a Department of Pharmaceutical Organic Chemistry , Faculty of Pharmacy, Helwan University , Cairo , Egypt
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11
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Liao X, Wang W, Fan C, Yang N, Zhao J, Zhang Y, Gao R, Shen G, Xia S, Li G. Prokaryotic expression, purification and characterization of human cyclooxygenase-2. Int J Mol Med 2017; 40:75-82. [PMID: 28560423 PMCID: PMC5466394 DOI: 10.3892/ijmm.2017.3007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 05/26/2017] [Indexed: 01/06/2023] Open
Abstract
Cyclooxygenase-2 (COX-2) is a key enzyme which catalyzes the conversion of arachidonic acid (AA) into prostaglandins (PGs). It plays an important role in pathophysiological processes, such as tumorigenesis, angiogenesis, inflammation and tumor cell drug resistance. Therefore, COX-2 has been viewed as an important target for cancer therapy. The preparation of COX-2 protein is an important initial step for the subsequent development of COX-2 inhibitors. In this study, we report a strategy to heterologously express truncated human COX-2 (trCOX-2) in Escherichia coli (E. coli) BL21(DE3) host cells. Following denaturation, purification and renaturation, we successfully obtained enzymatically active trCOX-2 containing 257 residues of the C-terminus. Homology modeling and molecular docking analyses revealed that trCOX-2 retained the predicted 3D catalytic domain structure and AA could still bind to its hydrophobic groove. Western blot analysis and ELISA indicated that the trCOX-2 still retained its characteristic antigenicity and binding activity, while COX assays revealed that trCOX-2 maintained its enzyme activity. On the whole, in this study, we provided a novel method to isolate trCOX-2 possessing AA binding and catalytic activities. This study thus lays a foundation to facilitate further investigations of COX-2 and offers a valuable method with which to achieve the prokaryotic expression of a eukaryotic membrane protein.
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Affiliation(s)
- Xiangzhi Liao
- Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education, College of Life Sciences, Jilin University, Changchun, Jilin 130012, P.R. China
| | - Wenhan Wang
- Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education, College of Life Sciences, Jilin University, Changchun, Jilin 130012, P.R. China
| | - Chuanxi Fan
- Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education, College of Life Sciences, Jilin University, Changchun, Jilin 130012, P.R. China
| | - Ning Yang
- Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education, College of Life Sciences, Jilin University, Changchun, Jilin 130012, P.R. China
| | - Jialiang Zhao
- Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education, College of Life Sciences, Jilin University, Changchun, Jilin 130012, P.R. China
| | - Ying Zhang
- Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education, College of Life Sciences, Jilin University, Changchun, Jilin 130012, P.R. China
| | - Ruijuan Gao
- Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education, College of Life Sciences, Jilin University, Changchun, Jilin 130012, P.R. China
| | - Guannan Shen
- Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education, College of Life Sciences, Jilin University, Changchun, Jilin 130012, P.R. China
| | - Simin Xia
- Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education, College of Life Sciences, Jilin University, Changchun, Jilin 130012, P.R. China
| | - Guiying Li
- Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education, College of Life Sciences, Jilin University, Changchun, Jilin 130012, P.R. China
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12
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Fowler CJ, Doherty P, Alexander SPH. Endocannabinoid Turnover. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2017; 80:31-66. [PMID: 28826539 DOI: 10.1016/bs.apha.2017.03.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In this review, we consider the biosynthetic, hydrolytic, and oxidative metabolism of the endocannabinoids anandamide and 2-arachidonoylglycerol. We describe the enzymes associated with these events and their characterization. We identify the inhibitor profile for these enzymes and the status of therapeutic exploitation, which to date has been limited to clinical trials for fatty acid amide hydrolase inhibitors. To bring the review to a close, we consider whether point block of a single enzyme is likely to be the most successful approach for therapeutic exploitation of the endocannabinoid system.
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Affiliation(s)
| | - Patrick Doherty
- Wolfson Centre for Age-Related Disease, King's College London, London, United Kingdom
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13
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Dong L, Yuan C, Orlando BJ, Malkowski MG, Smith WL. Fatty Acid Binding to the Allosteric Subunit of Cyclooxygenase-2 Relieves a Tonic Inhibition of the Catalytic Subunit. J Biol Chem 2016; 291:25641-25655. [PMID: 27756840 DOI: 10.1074/jbc.m116.757310] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 10/13/2016] [Indexed: 01/24/2023] Open
Abstract
Prostaglandin endoperoxide H synthase-2 (PGHS-2), also called cyclooxygenase-2 (COX-2), converts arachidonic acid to PGH2 PGHS-2 is a conformational heterodimer composed of allosteric (Eallo) and catalytic (Ecat) subunits. Fatty acids (FAs) bind to Arg-120 of Eallo increasing to different degrees, depending on the FA, the Vmax of its Ecat partner. We report here that movement of helical residues 120-122 and loop residues 123-129 of Eallo underlies the allosteric effects of FAs and allosteric COX-2 inhibitors, including naproxen and flurbiprofen. An S121P substitution in both PGHS-2 monomers yields a variant (S121P/S121P PGHS-2) that has 1.7-1.8 times the Vmax of native PGHS-2 and is relatively insensitive to activation by FAs or inhibition by allosteric inhibitors. The S121P substitution in Eallo is primarily responsible for these effects. In X-ray crystal structures, the Cα atoms of helical residues 119-122 of S121P/S121P PGHS-2 are displaced from their normal positions. Additionally, the S121P/S121P PGHS-2 variants in which Pro-127 and Ser-541 are replaced by cysteines spontaneously forms Cys-127 to Cys-541 cross-links between monomers. This is unlike the corresponding native PGHS-2 variant and suggests that S121P substitutions also unhinge the loop involving residues 123-129. We conclude the following: (a) the region involving residues 120-129 of unoccupied Eallo tonically inhibits Ecat; (b) binding of an activating FA (e.g. arachidonic, palmitic, or oleic acid) to Eallo or an S121P substitution in Eallo repositions this region to increase Ecat activity; and (c) allosteric COX inhibitors act by preventing FA binding to Eallo and additionally by relocating Eallo residues to inhibit Ecat.
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Affiliation(s)
- Liang Dong
- From the Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109 and
| | - Chong Yuan
- From the Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109 and
| | - Benjamin J Orlando
- the Department of Structural Biology, University at Buffalo, The State University of New York, and the Hauptman-Woodward Medical Research Institute, Buffalo, New York 14203
| | - Michael G Malkowski
- the Department of Structural Biology, University at Buffalo, The State University of New York, and the Hauptman-Woodward Medical Research Institute, Buffalo, New York 14203
| | - William L Smith
- From the Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109 and
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14
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Orlando BJ, Malkowski MG. Crystal structure of rofecoxib bound to human cyclooxygenase-2. Acta Crystallogr F Struct Biol Commun 2016; 72:772-776. [PMID: 27710942 PMCID: PMC5053162 DOI: 10.1107/s2053230x16014230] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 09/07/2016] [Indexed: 11/11/2022] Open
Abstract
Rofecoxib (Vioxx) was one of the first selective cyclooxygenase-2 (COX-2) inhibitors (coxibs) to be approved for use in humans. Within five years after its release to the public, Vioxx was withdrawn from the market owing to the adverse cardiovascular effects of the drug. Despite the widespread knowledge of the development and withdrawal of Vioxx, relatively little is known at the molecular level about how the inhibitor binds to COX-2. Vioxx is unique in that the inhibitor contains a methyl sulfone moiety in place of the sulfonamide moiety found in other coxibs such as celecoxib and valdecoxib. Here, new crystallization conditions were identified that allowed the structural determination of human COX-2 in complex with Vioxx and the structure was subsequently determined to 2.7 Å resolution. The crystal structure provides the first atomic level details of the binding of Vioxx to COX-2. As anticipated, Vioxx binds with its methyl sulfone moiety located in the side pocket of the cyclooxygenase channel, providing support for the isoform selectivity of this drug.
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Affiliation(s)
- Benjamin J. Orlando
- Department of Structural Biology, The State University of New York at Buffalo and the Hauptman–Woodward Medical Research Institute, 700 Ellicott Street, Buffalo, NY 14203, USA
| | - Michael G. Malkowski
- Department of Structural Biology, The State University of New York at Buffalo and the Hauptman–Woodward Medical Research Institute, 700 Ellicott Street, Buffalo, NY 14203, USA
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15
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Liu X, Moon SH, Jenkins CM, Sims HF, Gross RW. Cyclooxygenase-2 Mediated Oxidation of 2-Arachidonoyl-Lysophospholipids Identifies Unknown Lipid Signaling Pathways. Cell Chem Biol 2016; 23:1217-1227. [PMID: 27642067 DOI: 10.1016/j.chembiol.2016.08.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 07/27/2016] [Accepted: 08/02/2016] [Indexed: 12/27/2022]
Abstract
Eicosanoid lipids play important roles in cellular signaling as second messengers in inflammation, immune response, vascular tone, and the CNS. Biosynthesis of eicosanoid lipids proceeds via hydrolysis of esterified arachidonic acid from phospholipids followed by oxidation of the released arachidonic acid by a variety of enzymes including cyclooxygenases (COX). Herein, we demonstrate the remarkable ability of COX-2, but not COX-1, to directly oxidize 2-arachidonoyl-lysolipids, resulting in the generation of previously unknown classes of eicosanoid-lysolipids, and provide evidence that intracellular lipases can release eicosanoids from their eicosanoid-lysolipid precursors. Importantly, genetic ablation of a phospholipase, iPLA2γ, significantly reduced the amounts of these eicosanoid-lysolipids in murine hepatic tissue and fibroblasts. Furthermore, calcium stimulation of wild-type murine lung fibroblasts produced robust increases in these eicosanoid-lysolipids, which were markedly attenuated in iPLA2γ-/- fibroblasts. Collectively, these results identify an iPLA2γ-initiated pathway generating new classes of lipid metabolites with potential signaling functions resulting from the direct COX-2 catalyzed oxidation of 2-arachidonoyl-lysolipids.
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Affiliation(s)
- Xinping Liu
- Division of Bioorganic Chemistry and Molecular Pharmacology, Department of Medicine, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8020, Saint Louis, MO 63110, USA
| | - Sung Ho Moon
- Division of Bioorganic Chemistry and Molecular Pharmacology, Department of Medicine, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8020, Saint Louis, MO 63110, USA
| | - Christopher M Jenkins
- Division of Bioorganic Chemistry and Molecular Pharmacology, Department of Medicine, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8020, Saint Louis, MO 63110, USA
| | - Harold F Sims
- Division of Bioorganic Chemistry and Molecular Pharmacology, Department of Medicine, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8020, Saint Louis, MO 63110, USA
| | - Richard W Gross
- Division of Bioorganic Chemistry and Molecular Pharmacology, Department of Medicine, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8020, Saint Louis, MO 63110, USA; Department of Developmental Biology, Washington University School of Medicine, Saint Louis, MO 63110, USA; Department of Chemistry, Washington University, Saint Louis, MO 63130, USA.
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16
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Orlando BJ, Malkowski MG. Substrate-selective Inhibition of Cyclooxygeanse-2 by Fenamic Acid Derivatives Is Dependent on Peroxide Tone. J Biol Chem 2016; 291:15069-81. [PMID: 27226593 DOI: 10.1074/jbc.m116.725713] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Indexed: 12/13/2022] Open
Abstract
Cyclooxygenase-2 (COX-2) catalyzes the oxygenation of arachidonic acid (AA) and endocannabinoid substrates, placing the enzyme at a unique junction between the eicosanoid and endocannabinoid signaling pathways. COX-2 is a sequence homodimer, but the enzyme displays half-of-site reactivity, such that only one monomer of the dimer is active at a given time. Certain rapid reversible, competitive nonsteroidal anti-inflammatory drugs (NSAIDs) have been shown to inhibit COX-2 in a substrate-selective manner, with the binding of inhibitor to a single monomer sufficient to inhibit the oxygenation of endocannabinoids but not arachidonic acid. The underlying mechanism responsible for substrate-selective inhibition has remained elusive. We utilized structural and biophysical methods to evaluate flufenamic acid, meclofenamic acid, mefenamic acid, and tolfenamic acid for their ability to act as substrate-selective inhibitors. Crystal structures of each drug in complex with human COX-2 revealed that the inhibitor binds within the cyclooxygenase channel in an inverted orientation, with the carboxylate group interacting with Tyr-385 and Ser-530 at the top of the channel. Tryptophan fluorescence quenching, continuous-wave electron spin resonance, and UV-visible spectroscopy demonstrate that flufenamic acid, mefenamic acid, and tolfenamic acid are substrate-selective inhibitors that bind rapidly to COX-2, quench tyrosyl radicals, and reduce higher oxidation states of the heme moiety. Substrate-selective inhibition was attenuated by the addition of the lipid peroxide 15-hydroperoxyeicosatertaenoic acid. Collectively, these studies implicate peroxide tone as an important mechanistic component of substrate-selective inhibition by flufenamic acid, mefenamic acid, and tolfenamic acid.
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Affiliation(s)
- Benjamin J Orlando
- From the Department of Structural Biology, The State University of New York at Buffalo and
| | - Michael G Malkowski
- From the Department of Structural Biology, The State University of New York at Buffalo and the Hauptman-Woodward Medical Research Institute, Buffalo, New York 14203
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17
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Dong L, Zou H, Yuan C, Hong YH, Uhlson CL, Murphy RC, Smith WL. Interactions of 2-O-arachidonylglycerol ether and ibuprofen with the allosteric and catalytic subunits of human COX-2. J Lipid Res 2016; 57:1043-50. [PMID: 27059979 DOI: 10.1194/jlr.m067512] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2016] [Indexed: 11/20/2022] Open
Abstract
Prostaglandin (PG) endoperoxide H synthase (PGHS)-2, also known as cyclooxygenase (COX)-2, can convert arachidonic acid (AA) to PGH2 in the committed step of PG synthesis. PGHS-2 functions as a conformational heterodimer composed of an allosteric (Eallo) and a catalytic (Ecat) monomer. Here we investigated the interplay between human (hu)PGHS-2 and an alternative COX substrate, the endocannabinoid, 2-arachidonoylglycerol (2-AG), as well as a stable analog, 2-O-arachidonylglycerol ether (2-AG ether). We also compared the inhibition of huPGHS-2-mediated oxygenation of AA, 2-AG, and 2-AG ether by the well-known COX inhibitor, ibuprofen. When tested with huPGHS-2, 2-AG and 2-AG ether exhibit very similar kinetic parameters, responses to stimulation by FAs that are not COX substrates, and modes of inhibition by ibuprofen. The 2-AG ether binds Ecat more tightly than Eallo and, thus, can be used as a stable Ecat-specific substrate to examine certain Eallo-dependent responses. Ibuprofen binding to Eallo of huPGHS-2 completely blocks 2-AG or 2-AG ether oxygenation; however, inhibition by ibuprofen of huPGHS-2-mediated oxygenation of AA engages a combination of both allosteric and competitive mechanisms.
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Affiliation(s)
- Liang Dong
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109
| | - Hechang Zou
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109
| | - Chong Yuan
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109
| | - Yu H Hong
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109
| | - Charis L Uhlson
- Department of Pharmacology, University of Colorado-Denver, Aurora, CO 80045
| | - Robert C Murphy
- Department of Pharmacology, University of Colorado-Denver, Aurora, CO 80045
| | - William L Smith
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109
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18
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Lucido MJ, Orlando BJ, Vecchio AJ, Malkowski MG. Crystal Structure of Aspirin-Acetylated Human Cyclooxygenase-2: Insight into the Formation of Products with Reversed Stereochemistry. Biochemistry 2016; 55:1226-38. [PMID: 26859324 DOI: 10.1021/acs.biochem.5b01378] [Citation(s) in RCA: 121] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Aspirin and other nonsteroidal anti-inflammatory drugs target the cyclooxygenase enzymes (COX-1 and COX-2) to block the formation of prostaglandins. Aspirin is unique in that it covalently modifies each enzyme by acetylating Ser-530 within the cyclooxygenase active site. Acetylation of COX-1 leads to complete loss of activity, while acetylation of COX-2 results in the generation of the monooxygenated product 15(R)-hydroxyeicosatetraenoic acid (15R-HETE). Ser-530 has also been shown to influence the stereochemistry for the addition of oxygen to the prostaglandin product. We determined the crystal structures of S530T murine (mu) COX-2, aspirin-acetylated human (hu) COX-2, and huCOX-2 in complex with salicylate to 1.9, 2.0, and 2.4 Å, respectively. The structures reveal that (1) the acetylated Ser-530 completely blocks access to the hydrophobic groove, (2) the observed binding pose of salicylate is reflective of the enzyme-inhibitor complex prior to acetylation, and (3) the observed Thr-530 rotamer in the S530T muCOX-2 crystal structure does not impede access to the hydrophobic groove. On the basis of these structural observations, along with functional analysis of the S530T/G533V double mutant, we propose a working hypothesis for the generation of 15R-HETE by aspirin-acetylated COX-2. We also observe differential acetylation of COX-2 purified in various detergent systems and nanodiscs, indicating that detergent and lipid binding within the membrane-binding domain of the enzyme alters the rate of the acetylation reaction in vitro.
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Affiliation(s)
- Michael J Lucido
- Department of Structural Biology, The State University of New York at Buffalo and Hauptman-Woodward Medical Research Institute , Buffalo, New York 14203, United States
| | - Benjamin J Orlando
- Department of Structural Biology, The State University of New York at Buffalo and Hauptman-Woodward Medical Research Institute , Buffalo, New York 14203, United States
| | - Alex J Vecchio
- Department of Structural Biology, The State University of New York at Buffalo and Hauptman-Woodward Medical Research Institute , Buffalo, New York 14203, United States
| | - Michael G Malkowski
- Department of Structural Biology, The State University of New York at Buffalo and Hauptman-Woodward Medical Research Institute , Buffalo, New York 14203, United States
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19
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Competition and allostery govern substrate selectivity of cyclooxygenase-2. Proc Natl Acad Sci U S A 2015; 112:12366-71. [PMID: 26392530 DOI: 10.1073/pnas.1507307112] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cyclooxygenase-2 (COX-2) oxygenates arachidonic acid (AA) and its ester analog, 2-arachidonoylglycerol (2-AG), to prostaglandins (PGs) and prostaglandin glyceryl esters (PG-Gs), respectively. Although the efficiency of oxygenation of these substrates by COX-2 in vitro is similar, cellular biosynthesis of PGs far exceeds that of PG-Gs. Evidence that the COX enzymes are functional heterodimers suggests that competitive interaction of AA and 2-AG at the allosteric site of COX-2 might result in differential regulation of the oxygenation of the two substrates when both are present. Modulation of AA levels in RAW264.7 macrophages uncovered an inverse correlation between cellular AA levels and PG-G biosynthesis. In vitro kinetic analysis using purified protein demonstrated that the inhibition of 2-AG oxygenation by high concentrations of AA far exceeded the inhibition of AA oxygenation by high concentrations of 2-AG. An unbiased systems-based mechanistic model of the kinetic data revealed that binding of AA or 2-AG at the allosteric site of COX-2 results in a decreased catalytic efficiency of the enzyme toward 2-AG, whereas 2-AG binding at the allosteric site increases COX-2's efficiency toward AA. The results suggest that substrates interact with COX-2 via multiple potential complexes involving binding to both the catalytic and allosteric sites. Competition between AA and 2-AG for these sites, combined with differential allosteric modulation, gives rise to a complex interplay between the substrates, leading to preferential oxygenation of AA.
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20
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Kudalkar SN, Nikas SP, Kingsley PJ, Xu S, Galligan JJ, Rouzer CA, Banerjee S, Ji L, Eno MR, Makriyannis A, Marnett LJ. 13-Methylarachidonic acid is a positive allosteric modulator of endocannabinoid oxygenation by cyclooxygenase. J Biol Chem 2015; 290:7897-909. [PMID: 25648895 DOI: 10.1074/jbc.m114.634014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Cyclooxygenase-2 (COX-2) oxygenates arachidonic acid (AA) and the endocannabinoids 2-arachidonoylglycerol (2-AG) and arachidonylethanolamide to prostaglandins, prostaglandin glyceryl esters, and prostaglandin ethanolamides, respectively. A structural homodimer, COX-2 acts as a conformational heterodimer with a catalytic and an allosteric monomer. Prior studies have demonstrated substrate-selective negative allosteric regulation of 2-AG oxygenation. Here we describe AM-8138 (13(S)-methylarachidonic acid), a substrate-selective allosteric potentiator that augments 2-AG oxygenation by up to 3.5-fold with no effect on AA oxygenation. In the crystal structure of an AM-8138·COX-2 complex, AM-8138 adopts a conformation similar to the unproductive conformation of AA in the substrate binding site. Kinetic analysis suggests that binding of AM-8138 to the allosteric monomer of COX-2 increases 2-AG oxygenation by increasing kcat and preventing inhibitory binding of 2-AG. AM-8138 restored the activity of COX-2 mutants that exhibited very poor 2-AG oxygenating activity and increased the activity of COX-1 toward 2-AG. Competition of AM-8138 for the allosteric site prevented the inhibition of COX-2-dependent 2-AG oxygenation by substrate-selective inhibitors and blocked the inhibition of AA or 2-AG oxygenation by nonselective time-dependent inhibitors. AM-8138 selectively enhanced 2-AG oxygenation in intact RAW264.7 macrophage-like cells. Thus, AM-8138 is an important new tool compound for the exploration of allosteric modulation of COX enzymes and their role in endocannabinoid metabolism.
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Affiliation(s)
- Shalley N Kudalkar
- From the A. B. Hancock Jr. Memorial Laboratory for Cancer Research, Departments of Biochemistry
| | - Spyros P Nikas
- the Department of Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts 02115, and
| | - Philip J Kingsley
- From the A. B. Hancock Jr. Memorial Laboratory for Cancer Research, Departments of Biochemistry
| | - Shu Xu
- From the A. B. Hancock Jr. Memorial Laboratory for Cancer Research, Departments of Biochemistry
| | - James J Galligan
- From the A. B. Hancock Jr. Memorial Laboratory for Cancer Research, Departments of Biochemistry
| | - Carol A Rouzer
- From the A. B. Hancock Jr. Memorial Laboratory for Cancer Research, Vanderbilt Institute of Chemical Biology
| | - Surajit Banerjee
- the Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, and the Northeastern Collaborative Access Team, Argonne National Laboratory, Argonne, Illinois 60439
| | - Lipin Ji
- the Department of Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts 02115, and
| | - Marsha R Eno
- the Department of Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts 02115, and
| | - Alexandros Makriyannis
- the Department of Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts 02115, and
| | - Lawrence J Marnett
- From the A. B. Hancock Jr. Memorial Laboratory for Cancer Research, Departments of Biochemistry, Vanderbilt Institute of Chemical Biology, Chemistry, and Pharmacology, Vanderbilt Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, and Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146,
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21
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Xu S, Rouzer CA, Marnett LJ. Oxicams, a class of nonsteroidal anti-inflammatory drugs and beyond. IUBMB Life 2014; 66:803-11. [PMID: 25537198 DOI: 10.1002/iub.1334] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2014] [Accepted: 11/19/2014] [Indexed: 11/12/2022]
Abstract
Oxicams are a class of nonsteroidal anti-inflammatory drugs (NSAIDs) structurally related to the enolic acid class of 4-hydroxy-1,2-benzothiazine carboxamides. They are used clinically to treat both acute and chronic inflammation by inhibiting the activity of the two cyclooxygenase (COX) isoforms, COX-1 and COX-2. Oxicams are structurally distinct from all other NSAIDs, exhibiting a novel binding pose in the COX active site. The 4-hydroxyl group on the thiazine ring partners with Ser-530 via hydrogen bonding while two coordinated water molecules mediate a polar interaction between the oxicam and COX. The rotation of Leu-531 in the complex opens a new pocket, which is not used for binding other NSAIDs to the enzyme. This structure provides the basis for understanding documented structure-activity relationships within the oxicam class. In addition, from the oxicam template, a series of potent microsomal prostaglandin E synthase-1 (mPGES-1) inhibitors represents a new direction for drug development. Here, we review the major route of oxicam synthesis and structure-activity for COX inhibition, as well as recent advances in oxicam-mediated mPGES-1 inhibition.
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Affiliation(s)
- Shu Xu
- A.B. Hancock Jr. Memorial Laboratory for Cancer Research; Department of Biochemistry; Vanderbilt Institute of Chemical Biology
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22
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Orlando BJ, Lucido MJ, Malkowski MG. The structure of ibuprofen bound to cyclooxygenase-2. J Struct Biol 2014; 189:62-6. [PMID: 25463020 DOI: 10.1016/j.jsb.2014.11.005] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 11/14/2014] [Accepted: 11/18/2014] [Indexed: 02/04/2023]
Abstract
The cyclooxygenases (COX-1 and COX-2) catalyze the rate-limiting step in the biosynthesis of prostaglandins, and are the pharmacological targets of non-steroidal anti-inflammatory drugs (NSAIDs) and COX-2 selective inhibitors (coxibs). Ibuprofen (IBP) is one of the most commonly available over-the-counter pharmaceuticals in the world. The anti-inflammatory and analgesic properties of IBP are thought to arise from inhibition of COX-2 rather than COX-1. While an X-ray crystal structure of IBP bound to COX-1 has been solved, no such structure exists for the cognate isoform COX-2. We have determined the crystal structure of muCOX-2 with a racemic mixture of (R/S)-IBP. Our structure reveals that only the S-isomer of IBP was bound, indicating that the S-isomer possesses higher affinity for COX-2 than the R-isomer. Mutational analysis of Arg-120 and Tyr-355 at the entrance of the cyclooxygenase channel confirmed their role in binding and inhibition of COX-2 by IBP. Our results provide the first atomic level detail of the interaction between IBP and COX-2.
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Affiliation(s)
- Benjamin J Orlando
- Department of Structural Biology, The State University of New York at Buffalo and the Hauptman-Woodward Medical Research Institute, 700 Ellicott Street, Buffalo, NY 14203, USA
| | - Michael J Lucido
- Department of Structural Biology, The State University of New York at Buffalo and the Hauptman-Woodward Medical Research Institute, 700 Ellicott Street, Buffalo, NY 14203, USA
| | - Michael G Malkowski
- Department of Structural Biology, The State University of New York at Buffalo and the Hauptman-Woodward Medical Research Institute, 700 Ellicott Street, Buffalo, NY 14203, USA.
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23
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Kukk K, Kasvandik S, Samel N. N-glycosylation site occupancy in human prostaglandin H synthases expressed in Pichia pastoris. SPRINGERPLUS 2014; 3:436. [PMID: 25170432 PMCID: PMC4147080 DOI: 10.1186/2193-1801-3-436] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 08/12/2014] [Indexed: 11/10/2022]
Abstract
Prostaglandin H synthases (PGHSs) are N-glycosylated membrane proteins that catalyse the committed step in prostaglandin synthesis. Unlike PGHS-2, the production of recombinant PGHS-1 in non-mammalian expression systems is complicated. The majority of the heterologous enzyme is inactive due to misfolding. Correct N-glycosylation is proposed to be obligatory for proper folding of mammalian PGHSs. In this study, human PGHS-1 and -2 (hPGHS-1 and -2) were expressed in the yeast Pichia pastoris. Recombinant hPGHS-2 was catalytically active, whereas hPGHS-1 was inactive. Accumulation of non-glycosylated hPGHSs was not observed in the crude lysate of the yeast cells. The N-glycosylation patterns of the purified recombinant proteins were characterised using nano-LC/MS/MS. The isoforms exhibited similar N-glycosylation site occupancy. The results indicate that there are more complex grounds for the inactivity of the recombinant hPGHS-1 produced in yeast.
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Affiliation(s)
- Kaia Kukk
- Department of Chemistry, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia
| | - Sergo Kasvandik
- Proteomics Core Facility, Institute of Technology, University of Tartu, Nooruse 1, 50411 Tartu, Estonia
| | - Nigulas Samel
- Department of Chemistry, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia
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24
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Kim J, Watkins BA. Cannabinoid receptor antagonists and fatty acids alter endocannabinoid system gene expression and COX activity. J Nutr Biochem 2014; 25:815-23. [DOI: 10.1016/j.jnutbio.2014.03.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Revised: 03/10/2014] [Accepted: 03/11/2014] [Indexed: 12/21/2022]
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25
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Karlsson J, Fowler CJ. Inhibition of endocannabinoid metabolism by the metabolites of ibuprofen and flurbiprofen. PLoS One 2014; 9:e103589. [PMID: 25061885 PMCID: PMC4111603 DOI: 10.1371/journal.pone.0103589] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 06/28/2014] [Indexed: 02/02/2023] Open
Abstract
Background In addition to their effects upon prostaglandin synthesis, the non-steroidal anti-inflammatory drugs ibuprofen and flurbiprofen inhibit the metabolism of the endocannabinoids 2-arachidonoylglycerol (2-AG) and anandamide (AEA) by cyclooxygenase-2 (COX-2) and fatty acid amide hydrolase (FAAH), respectively. Here, we investigated whether these effects upon endocannabinoid metabolism are shared by the main metabolites of ibuprofen and flurbiprofen. Methodology/Principal Findings COX activities were measured via changes in oxygen consumption due to oxygenation of arachidonic acid (for COX-1) and arachidonic acid and 2-AG (for COX-2). FAAH activity was quantified by measuring hydrolysis of tritium labelled AEA in rat brain homogenates. The ability of ibuprofen and flurbiprofen to inhibit COX-2-catalysed oxygenation of 2-AG at lower concentrations than the oxygenation of arachidonic acid was seen with 4′-hydroxyflurbiprofen and possibly also 3′-hydroxyibuprofen, albeit at lower potencies than the parent compounds. All ibuprofen and flurbiprofen metabolites retained the ability to inhibit FAAH in a pH-dependent manner, although the potency was lower than seen with the parent compounds. Conclusions/Significance It is concluded that the primary metabolites of ibuprofen and flurbiprofen retain some of the properties of the parent compound with respect to inhibition of endocannabinoid metabolism. However, these effects are unlikely to contribute to the actions of the parent compounds in vivo.
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Affiliation(s)
- Jessica Karlsson
- Department of Pharmacology and Clinical Neuroscience, Umeå University, Umeå, Sweden
- * E-mail:
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26
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Hermanson DJ, Gamble-George JC, Marnett LJ, Patel S. Substrate-selective COX-2 inhibition as a novel strategy for therapeutic endocannabinoid augmentation. Trends Pharmacol Sci 2014; 35:358-67. [PMID: 24845457 PMCID: PMC4074568 DOI: 10.1016/j.tips.2014.04.006] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Revised: 04/17/2014] [Accepted: 04/22/2014] [Indexed: 12/20/2022]
Abstract
Pharmacologic augmentation of endogenous cannabinoid (eCB) signaling is an emerging therapeutic approach for the treatment of a broad range of pathophysiological conditions. Thus far, pharmacological approaches have focused on inhibition of the canonical eCB inactivation pathways - fatty acid amide hydrolase (FAAH) for anandamide and monoacylglycerol lipase (MAGL) for 2-arachidonoylglycerol. We review here the experimental evidence that cyclooxygenase-2 (COX-2)-mediated eCB oxygenation represents a third mechanism for terminating eCB action at cannabinoid receptors. We describe the development, molecular mechanisms, and in vivo validation of 'substrate-selective' COX-2 inhibitors (SSCIs) that prevent eCB inactivation by COX-2 without affecting prostaglandin (PG) generation from arachidonic acid (AA). Lastly, we review recent data on the potential therapeutic applications of SSCIs with a focus on neuropsychiatric disorders.
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Affiliation(s)
- Daniel J Hermanson
- A.B. Hancock Jr Memorial Laboratory for Cancer Research, Departments of Biochemistry, Chemistry, and Pharmacology, Vanderbilt Institute of Chemical Biology Center in Molecular Toxicology and Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Joyonna C Gamble-George
- Department of Psychiatry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Lawrence J Marnett
- A.B. Hancock Jr Memorial Laboratory for Cancer Research, Departments of Biochemistry, Chemistry, and Pharmacology, Vanderbilt Institute of Chemical Biology Center in Molecular Toxicology and Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
| | - Sachin Patel
- Department of Psychiatry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
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27
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Alhouayek M, Muccioli GG. COX-2-derived endocannabinoid metabolites as novel inflammatory mediators. Trends Pharmacol Sci 2014; 35:284-92. [PMID: 24684963 DOI: 10.1016/j.tips.2014.03.001] [Citation(s) in RCA: 177] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 02/27/2014] [Accepted: 03/03/2014] [Indexed: 11/24/2022]
Abstract
Cyclooxygenase-2 (COX-2) is an enzyme that plays a key role in inflammatory processes. Classically, this enzyme is upregulated in inflammatory situations and is responsible for the generation of prostaglandins (PGs) from arachidonic acid (AA). One lesser-known property of COX-2 is its ability to metabolize the endocannabinoids, N-arachidonoylethanolamine (AEA) and 2-arachidonoylglycerol (2-AG). Endocannabinoid metabolism by COX-2 is not merely a means to terminate their actions. On the contrary, it generates PG analogs, namely PG-glycerol esters (PG-G) for 2-AG and PG-ethanolamides (PG-EA or prostamides) for AEA. Although the formation of these COX-2-derived metabolites of the endocannabinoids has been known for a while, their biological effects remain to be fully elucidated. Recently, several studies have focused on the role of these PG-G or PG-EA in vivo. In this review we take a closer look at the literature concerning these novel bioactive lipids and their role in inflammation.
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Affiliation(s)
- Mireille Alhouayek
- Bioanalysis and Pharmacology of Bioactive Lipids Research Group, Louvain Drug Research Institute, Université catholique de Louvain, Avenue Emmanuel Mounier 72 (B1.72.01), 1200 Bruxelles, Belgium
| | - Giulio G Muccioli
- Bioanalysis and Pharmacology of Bioactive Lipids Research Group, Louvain Drug Research Institute, Université catholique de Louvain, Avenue Emmanuel Mounier 72 (B1.72.01), 1200 Bruxelles, Belgium.
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28
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Xu S, Hermanson DJ, Banerjee S, Ghebreselasie K, Clayton GM, Garavito RM, Marnett LJ. Oxicams bind in a novel mode to the cyclooxygenase active site via a two-water-mediated H-bonding Network. J Biol Chem 2014; 289:6799-6808. [PMID: 24425867 DOI: 10.1074/jbc.m113.517987] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Oxicams are widely used nonsteroidal anti-inflammatory drugs (NSAIDs), but little is known about the molecular basis of the interaction with their target enzymes, the cyclooxygenases (COX). Isoxicam is a nonselective inhibitor of COX-1 and COX-2 whereas meloxicam displays some selectivity for COX-2. Here we report crystal complexes of COX-2 with isoxicam and meloxicam at 2.0 and 2.45 angstroms, respectively, and a crystal complex of COX-1 with meloxicam at 2.4 angstroms. These structures reveal that the oxicams bind to the active site of COX-2 using a binding pose not seen with other NSAIDs through two highly coordinated water molecules. The 4-hydroxyl group on the thiazine ring partners with Ser-530 via hydrogen bonding, and the heteroatom of the carboxamide ring of the oxicam scaffold interacts with Tyr-385 and Ser-530 through a highly coordinated water molecule. The nitrogen atom of the thiazine and the oxygen atom of the carboxamide bind to Arg-120 and Tyr-355 via another highly ordered water molecule. The rotation of Leu-531 in the structure opens a novel binding pocket, which is not utilized for the binding of other NSAIDs. In addition, a detailed study of meloxicam·COX-2 interactions revealed that mutation of Val-434 to Ile significantly reduces inhibition by meloxicam due to subtle changes around Phe-518, giving rise to the preferential inhibition of COX-2 over COX-1.
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Affiliation(s)
- Shu Xu
- A. B. Hancock Jr. Memorial Laboratory for Cancer Research, Departments of Biochemistry, Chemistry, and Pharmacology, Vanderbilt Institute of Chemical Biology, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
| | - Daniel J Hermanson
- A. B. Hancock Jr. Memorial Laboratory for Cancer Research, Departments of Biochemistry, Chemistry, and Pharmacology, Vanderbilt Institute of Chemical Biology, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
| | - Surajit Banerjee
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853; Northeastern Collaborative Access Team, Argonne National Laboratory, Argonne, Illinois 60439
| | - Kebreab Ghebreselasie
- A. B. Hancock Jr. Memorial Laboratory for Cancer Research, Departments of Biochemistry, Chemistry, and Pharmacology, Vanderbilt Institute of Chemical Biology, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
| | - Gina M Clayton
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
| | - R Michael Garavito
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
| | - Lawrence J Marnett
- A. B. Hancock Jr. Memorial Laboratory for Cancer Research, Departments of Biochemistry, Chemistry, and Pharmacology, Vanderbilt Institute of Chemical Biology, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232.
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29
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Windsor MA, Valk PL, Xu S, Banerjee S, Marnett LJ. Exploring the molecular determinants of substrate-selective inhibition of cyclooxygenase-2 by lumiracoxib. Bioorg Med Chem Lett 2013; 23:5860-4. [PMID: 24060487 DOI: 10.1016/j.bmcl.2013.08.097] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 08/22/2013] [Accepted: 08/26/2013] [Indexed: 01/22/2023]
Abstract
Lumiracoxib is a substrate-selective inhibitor of endocannabinoid oxygenation by cyclooxygenase-2 (COX-2). We assayed a series of lumiracoxib derivatives to identify the structural determinants of substrate-selective inhibition. The hydrogen-bonding potential of the substituents at the ortho positions of the aniline ring dictated the potency and substrate selectivity of the inhibitors. The presence of a 5'-methyl group on the phenylacetic acid ring increased the potency of molecules with a single ortho substituent. Des-fluorolumiracoxib (2) was the most potent and selective inhibitor of endocannabinoid oxygenation. The positioning of critical substituents in the binding site was identified from a 2.35Å crystal structure of lumiracoxib bound to COX-2.
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Affiliation(s)
- Matthew A Windsor
- A.B. Hancock Jr. Memorial Laboratory for Cancer Research, Department of Biochemistry, Department of Chemistry, Department of Pharmacology, Vanderbilt Institute of Chemical Biology, Center in Molecular Toxicology, and Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN, United States
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30
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Dong L, Sharma NP, Jurban BJ, Smith WL. Pre-existent asymmetry in the human cyclooxygenase-2 sequence homodimer. J Biol Chem 2013; 288:28641-55. [PMID: 23955344 DOI: 10.1074/jbc.m113.505503] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Prostaglandin endoperoxide H synthase-2 (PGHS-2), also known as cyclooxygenase-2 (COX-2), is a sequence homodimer. However, the enzyme exhibits half-site heme and inhibitor binding and functions as a conformational heterodimer having a catalytic subunit (Ecat) with heme bound and an allosteric subunit (Eallo) lacking heme. Some recombinant heterodimers composed of a COX-deficient mutant subunit and a native subunit (i.e. Mutant/Native PGHS-2) have COX activities similar to native PGHS-2. This suggests that the presence of heme plus substrate leads to the subunits becoming lodged in a semi-stable Eallo-mutant/Ecat-Native∼heme form during catalysis. We examined this concept using human PGHS-2 dimers composed of combinations of Y385F, R120Q, R120A, and S530A mutant or native subunits. With some heterodimers (e.g. Y385F/Native PGHS-2), heme binds with significantly higher affinity to the native subunit. This correlates with near native COX activity for the heterodimer. With other heterodimers (e.g. S530A/Native PGHS-2), heme binds with similar affinities to both subunits, and the COX activity approximates that expected for an enzyme in which each monomer contributes equally to the net COX activity. With or without heme, aspirin acetylates one-half of the subunits of the native PGHS-2 dimer, the Ecat subunits. Subunits having an S530A mutation are refractory to acetylation. Curiously, aspirin acetylates only one-quarter of the monomers of S530A/Native PGHS-2 with or without heme. This implies that there are comparable amounts of two noninterchangeable species of apoenzymes, Eallo-S530A/Ecat-Native and Eallo-Native/Ecat-S530A. These results suggest that native PGHS-2 assumes a reasonably stable, asymmetric Eallo/Ecat form during its folding and processing.
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Affiliation(s)
- Liang Dong
- From the Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109
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31
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Varvas K, Kasvandik S, Hansen K, Järving I, Morell I, Samel N. Structural and catalytic insights into the algal prostaglandin H synthase reveal atypical features of the first non-animal cyclooxygenase. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1831:863-71. [DOI: 10.1016/j.bbalip.2012.11.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Revised: 11/06/2012] [Accepted: 11/27/2012] [Indexed: 10/27/2022]
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32
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NSAIDs: eNdocannabinoid stimulating anti-inflammatory drugs? Trends Pharmacol Sci 2012; 33:468-73. [DOI: 10.1016/j.tips.2012.05.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Revised: 04/13/2012] [Accepted: 05/07/2012] [Indexed: 02/02/2023]
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33
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Musee J, Marnett LJ. Prostaglandin H synthase-2-catalyzed oxygenation of 2-arachidonoylglycerol is more sensitive to peroxide tone than oxygenation of arachidonic acid. J Biol Chem 2012; 287:37383-94. [PMID: 22942274 DOI: 10.1074/jbc.m112.381202] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The endocannabinoid, 2-arachidonoylglycerol (2-AG), is a selective substrate for the inducible isoform of prostaglandin H synthase (PGHS), PGHS-2. Its turnover leads to the formation of glyceryl esters of prostaglandins (PG-Gs), a subset of which elicits agonism at unique, as yet unidentified, receptors. The k(cat)/K(m) values for oxygenation of arachidonic acid (AA) and 2-AG by PGHS-2 are very similar, but the sensitivities of the two substrates to peroxide-dependent activation have not been compared. 15-Hydroperoxy derivatives of AA and 2-AG were found to be comparable in their ability to serve as substrates for the peroxidase activities of PGHS-2, PGHS-1, and glutathione peroxidase (GPx). They also were comparable in the activation of AA oxygenation by cyanide-inhibited PGHS-2. However, oxygenation of 2-AG was significantly suppressed relative to AA by the presence of GPx and GSH. Furthermore, 2-AG oxygenation by peroxidase-deficient H388YmPGHS-2 was much less efficient than AA oxygenation. Wild-type rates of 2-AG oxygenation were restored by treatment of H388YmPGHS-2 with hydroperoxide derivatives of AA or 2-AG. RNAi silencing of phospholipid hydroperoxide-specific GPx (GPx4) in NIH/3T3 cells led to increases in cellular peroxidation and in the levels of the isoprostane product, 8-epi-PGF(2α). GPx4 silencing led to 2-4-fold increases in PG-G formation but no change in PG formation. Thus, cellular peroxide tone may be an important determinant of the extent of endocannabinoid oxygenation by PGHS-2.
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Affiliation(s)
- Joel Musee
- A. B. Hancock Jr. Memorial Laboratory for Cancer Research, Department of Biochemistry, Vanderbilt Institute of Chemical Biology, Center in Molecular Toxicology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146, USA
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34
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Vecchio AJ, Orlando BJ, Nandagiri R, Malkowski MG. Investigating substrate promiscuity in cyclooxygenase-2: the role of Arg-120 and residues lining the hydrophobic groove. J Biol Chem 2012; 287:24619-30. [PMID: 22637474 DOI: 10.1074/jbc.m112.372243] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The cyclooxygenases (COX-1 and COX-2) generate prostaglandin H(2) from arachidonic acid (AA). In its catalytically productive conformation, AA binds within the cyclooxygenase channel with its carboxylate near Arg-120 and Tyr-355 and ω-end located within a hydrophobic groove above Ser-530. Although AA is the preferred substrate for both isoforms, COX-2 can oxygenate a broad spectrum of substrates. Mutational analyses have established that an interaction of the carboxylate of AA with Arg-120 is required for high affinity binding by COX-1 but not COX-2, suggesting that hydrophobic interactions between the ω-end of substrates and cyclooxygenase channel residues play a significant role in COX-2-mediated oxygenation. We used structure-function analyses to investigate the role that Arg-120 and residues lining the hydrophobic groove play in the binding and oxygenation of substrates by murine (mu) COX-2. Mutations to individual amino acids within the hydrophobic groove exhibited decreased rates of oxygenation toward AA with little effect on binding. R120A muCOX-2 oxygenated 18-carbon ω-6 and ω-3 substrates albeit at reduced rates, indicating that an interaction with Arg-120 is not required for catalysis. Structural determinations of Co(3+)-protoporphyrin IX-reconstituted muCOX-2 with α-linolenic acid and G533V muCOX-2 with AA indicate that proper bisallylic carbon alignment is the major determinant for efficient substrate oxygenation by COX-2. Overall, these findings implicate Arg-120 and hydrophobic groove residues as determinants that govern proper alignment of the bisallylic carbon below Tyr-385 for catalysis in COX-2 and confirm nuances between COX isoforms that explain substrate promiscuity.
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Affiliation(s)
- Alex J Vecchio
- Hauptman-Woodward Medical Research Institute and Department of Structural Biology, The State University of New York, Buffalo, New York 14203, USA
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35
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Gatta L, Piscitelli F, Giordano C, Boccella S, Lichtman A, Maione S, Di Marzo V. Discovery of prostamide F2α and its role in inflammatory pain and dorsal horn nociceptive neuron hyperexcitability. PLoS One 2012; 7:e31111. [PMID: 22363560 PMCID: PMC3283613 DOI: 10.1371/journal.pone.0031111] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Accepted: 01/02/2012] [Indexed: 11/18/2022] Open
Abstract
It was suggested that endocannabinoids are metabolized by cyclooxygenase (COX)-2 in the spinal cord of rats with kaolin/λ-carrageenan-induced knee inflammation, and that this mechanism contributes to the analgesic effects of COX-2 inhibitors in this experimental model. We report the development of a specific method for the identification of endocannabinoid COX-2 metabolites, its application to measure the levels of these compounds in tissues, and the finding of prostamide F2α (PMF2α) in mice with knee inflammation. Whereas the levels of spinal endocannabinoids were not significantly altered by kaolin/λ-carrageenan-induced knee inflammation, those of the COX-2 metabolite of AEA, PMF2α, were strongly elevated. The formation of PMF2α was reduced by indomethacin (a non-selective COX inhibitor), NS-398 (a selective COX-2 inhibitor) and SC-560 (a selective COX-1 inhibitor). In healthy mice, spinal application of PMF2α increased the firing of nociceptive (NS) neurons, and correspondingly reduced the threshold of paw withdrawal latency (PWL). These effects were attenuated by the PMF2α receptor antagonist AGN211336, but not by the FP receptor antagonist AL8810. Also prostaglandin F2α increased NS neuron firing and reduced the threshold of PWL in healthy mice, and these effects were antagonized by AL8810, and not by AGN211336. In mice with kaolin/λ-carrageenan-induced knee inflammation, AGN211336, but not AL8810, reduced the inflammation-induced NS neuron firing and reduction of PWL. These findings suggest that inflammation-induced, and prostanoid-mediated, enhancement of dorsal horn NS neuron firing stimulates the production of spinal PMF2α, which in turn contributes to further NS neuron firing and pain transmission by activating specific receptors.
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Affiliation(s)
- Luisa Gatta
- Endocannabinoid Research Group, Department of Experimental Medicine–Division of Pharmacology “L. Donatelli”, Second University of Naples, Naples, Italy
| | - Fabiana Piscitelli
- Endocannabinoid Research Group, Institute of Biomolecular Chemistry, C.N.R., Pozzuoli, Italy
| | - Catia Giordano
- Endocannabinoid Research Group, Department of Experimental Medicine–Division of Pharmacology “L. Donatelli”, Second University of Naples, Naples, Italy
| | - Serena Boccella
- Endocannabinoid Research Group, Department of Experimental Medicine–Division of Pharmacology “L. Donatelli”, Second University of Naples, Naples, Italy
| | - Aron Lichtman
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, School of Medicine, Richmond, Virginia, United States of America
| | - Sabatino Maione
- Endocannabinoid Research Group, Department of Experimental Medicine–Division of Pharmacology “L. Donatelli”, Second University of Naples, Naples, Italy
- * E-mail: (SM); (VD)
| | - Vincenzo Di Marzo
- Endocannabinoid Research Group, Institute of Biomolecular Chemistry, C.N.R., Pozzuoli, Italy
- * E-mail: (SM); (VD)
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Fowler CJ, Björklund E, Lichtman AH, Naidu PS, Congiu C, Onnis V. Inhibitory properties of ibuprofen and its amide analogues towards the hydrolysis and cyclooxygenation of the endocannabinoid anandamide. J Enzyme Inhib Med Chem 2012; 28:172-82. [PMID: 22225576 DOI: 10.3109/14756366.2011.643304] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
A dual-action cyclooxygenase (COX)-fatty acid amide hydrolase (FAAH) inhibitor may have therapeutic usefulness as an analgesic, but a key issue is finding the right balance of inhibitory effects. This can be done by the design of compounds exhibiting different FAAH/COX-inhibitory potencies. In the present study, eight ibuprofen analogues were investigated. Ibuprofen (1), 2-(4-Isobutylphenyl)-N-(2-(3-methylpyridin-2-ylamino)-2-oxoethyl)propanamide (9) and N-(3-methylpyridin-2-yl)-2-(4'-isobutylphenyl)propionamide (2) inhibited FAAH with IC(50) values of 134, 3.6 and 0.52 µM respectively. The corresponding values for COX-1 were ~29, ~50 and ~60 µM, respectively. Using arachidonic acid as substrate, the compounds were weak inhibitors of COX-2. However, when anandamide was used as COX-2 substrate, potency increased, with approximate IC(50) values of ~6, ~10 and ~19 µM, respectively. Compound 2 was confirmed to be active in vivo in a murine model of visceral nociception, but the effects of the compound were not blocked by CB receptor antagonists.
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Affiliation(s)
- Christopher J Fowler
- Department of Pharmacology and Clinical Neuroscience, Umeå University, Umeå, Sweden.
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Smith WL, Urade Y, Jakobsson PJ. Enzymes of the cyclooxygenase pathways of prostanoid biosynthesis. Chem Rev 2011; 111:5821-65. [PMID: 21942677 PMCID: PMC3285496 DOI: 10.1021/cr2002992] [Citation(s) in RCA: 342] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- William L Smith
- Department of Biological Chemistry, University of Michigan Medical School, 1150 West Medical Center Drive, 5301 MSRB III, Ann Arbor, Michigan 48109-5606, USA.
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Rouzer CA, Marnett LJ. Endocannabinoid oxygenation by cyclooxygenases, lipoxygenases, and cytochromes P450: cross-talk between the eicosanoid and endocannabinoid signaling pathways. Chem Rev 2011; 111:5899-921. [PMID: 21923193 PMCID: PMC3191732 DOI: 10.1021/cr2002799] [Citation(s) in RCA: 223] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2011] [Indexed: 12/12/2022]
Affiliation(s)
- Carol A Rouzer
- A.B. Hancock Jr. Memorial Laboratory for Cancer Research, Department of Biochemistry, Vanderbilt Institute of Chemical Biology, Center in Molecular Toxicology, Vanderbilt Ingram Comprehensive Cancer Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146, USA
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39
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Vecchio AJ, Malkowski MG. The structure of NS-398 bound to cyclooxygenase-2. J Struct Biol 2011; 176:254-8. [PMID: 21843643 DOI: 10.1016/j.jsb.2011.07.019] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Revised: 07/26/2011] [Accepted: 07/27/2011] [Indexed: 11/29/2022]
Abstract
The cyclooxygenases (COX-1 and COX-2) are membrane-associated, heme-containing homodimers that generate prostaglandin H(2) from arachidonic acid (AA) in the committed step of prostaglandin biogenesis and are the targets for nonsteroidal anti-inflammatory drugs (NSAIDs). N-(2-cyclohexyloxy-4-nitrophenyl) methanesulfonamide (NS-398) was the first in a series of isoform-selective drugs designed to preferentially inhibit COX-2, with the aim of ameliorating many of the toxic gastrointestinal side effects caused by conventional NSAID inhibition. We determined the X-ray crystal structure of murine COX-2 in complex with NS-398 utilizing synchrotron radiation to 3.0A resolution. NS-398 binds in the cyclooxygenase channel in a conformation that is different than that observed for other COX-2-selective inhibitors, such as celecoxib, with no discernible penetration into the side pocket formed in COX-2 by the isoform-specific substitutions of I434V, H513R, and I523V. Instead, the methanesulfonamide moiety of NS-398 interacts with the side chain of Arg-120 at the opening of the cyclooxygenase channel, similar to that observed for acidic, nonselective NSAIDs such as indomethacin and flurbiprofen. Our structure validates inhibitor studies that identified Arg-120 as a molecular determinant for time-dependent inhibition of COX-2 by NS-398.
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Affiliation(s)
- Alex J Vecchio
- Hauptman-Woodward Medical Research Institute, The State University of New York at Buffalo, 700 Ellicott Street, Buffalo, NY 14203, USA
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