1
|
Qiu Q, Abis G, Mattingly-Peck F, Lynham S, Fraternali F, Conte MR. Allosteric regulation of the soluble epoxide hydrolase by nitro fatty acids using a combined experimental and computational approach. J Mol Biol 2022; 434:167600. [PMID: 35460669 DOI: 10.1016/j.jmb.2022.167600] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 03/31/2022] [Accepted: 04/17/2022] [Indexed: 11/18/2022]
Abstract
The human soluble epoxide hydrolase (hsEH) is a key regulator of epoxy fatty acid (EpFA) metabolism. Inhibition of sEH can maintain endogenous levels of beneficial EpFAs and reduce the levels of their corresponding diol products, thus ameliorating a variety of pathological conditions including cardiovascular, central nervous system and metabolic diseases. The quest for orthosteric drugs that bind directly to the catalytic crevice of hsEH has been prolonged and sustained over the past decades, but the disappointing outcome of clinical trials to date warrants alternative pharmacological approaches. Previously, we have shown that hsEH can be allosterically inhibited by the endogenous electrophilic lipid 15-deoxy-Δ12,14-Prostaglandin-J2, via covalent adduction to two cysteines, C423 and C522. In this study, we explore the properties and behaviour of three electrophilic lipids belonging to the class of the nitro fatty acids, namely 9- and 10-nitrooleate and 10-nitrolinoleate. Biochemical and biophysical investigations revealed that, in addition to C423 and C522, nitro fatty acids can covalently bind to additional nucleophilic residues in hsEH C-terminal domain (CTD), two of which predicted in this study to be latent allosteric sites. Systematic mapping of the protein mutational space and evaluation of possible propagation pathways delineated selected residues, both in the allosteric patches and in other regions of the enzyme, envisaged to play a role on allosteric signalling. The responses elicited by the ligands on the covalent adduction sites supports future fragment-based design studies of new allosteric effectors for hsEH with increased efficacy and selectivity.
Collapse
Affiliation(s)
- Qiongju Qiu
- Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, King's College London, London SE1 1UL, UK
| | - Giancarlo Abis
- Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, King's College London, London SE1 1UL, UK
| | - Florence Mattingly-Peck
- Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, King's College London, London SE1 1UL, UK
| | - Steven Lynham
- Proteomics Facility, Centre of Excellence for Mass Spectrometry, The James Black Centre, King's College London, London SE5 9NU, UK
| | - Franca Fraternali
- Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, King's College London, London SE1 1UL, UK.
| | - Maria R Conte
- Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, King's College London, London SE1 1UL, UK.
| |
Collapse
|
2
|
Umeda N, Hirai T, Ohto-Nakanishi T, Tsuchiya KJ, Matsuzaki H. Linoleic acid and linoleate diols in neonatal cord blood influence birth weight. Front Endocrinol (Lausanne) 2022; 13:986650. [PMID: 36093109 PMCID: PMC9453817 DOI: 10.3389/fendo.2022.986650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 08/05/2022] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND Low-birth-weight infants exhibit a high risk for postnatal morbidity. Cytochrome P450 (CYP) and epoxide hydrolase (EH) are involved in the metabolism of factors responsible for low-birth-weight in infants. Both CYPs and EHs have high substrate specificity and are involved in polyunsaturated fatty acid (PUFA) metabolism. The CYP pathway produces epoxy fatty acids (EpFAs), which are further degraded by soluble EH (sEH). Additionally, sEH inhibition enhances the action of EpFAs and suppresses inflammatory responses. During pregnancy, excessive activation of maternal inflammatory response is a significant factor associated with low-birth-weight. However, the association of EpFAs, which have potential anti-inflammatory properties, with the low-birth-weight of infants remains uninvestigated. This study aimed to clarify the association between the umbilical cord serum EpFA and low-birth-weight using data obtained from the Hamamatsu Birth Cohort for Mothers and Children (HBC Study) by analyzing the umbilical cord blood samples. METHOD We selected a subgroup of 200 infants (106 boys and 94 girls), quantified EpFA concentration in their cord blood samples collected at birth, and examined its correlation with birth weight. RESULTS The comparison between the low-birth-weight and normal-birth-weight groups revealed no significant correlation between PUFA and EpFA concentrations, but a significant correlation was observed in the linoleate diol concentrations of the two groups. Furthermore, birth weight did not significantly correlate with PUFA, EpFA, and diol concentrations in cord blood; however, multiple regression analysis showed a significant negative correlation of birth weight with the concentration of linoleic acid (LA) (r = -0.101, p = 0.016) as well as LA-derived dihydroxyoctadecenoic acid (diHOME) (r = -0.126, p = 0.007), 9,10-diHOME (r = -0.115, p = 0.014), and 12,13-diHOME (r = -0.126, p = 0.007) after adjusting for obstetric factors, including gestational age, infant's sex, childbirth history, delivery method, and maternal height. CONCLUSIONS Birth weight was significantly correlated with the concentration of LA and linoleate diol diHOME after adjusting for obstetric confounders. Our results show that CYP and sEH involved in PUFA metabolism may influence the birth weight of infants. Further validation is needed to provide insights regarding maternal intervention strategies required to avoid low-birth-weight in infants in the future.
Collapse
Affiliation(s)
- Naoko Umeda
- Department of Functional Brain Activities, United Graduate School of Child Development, Hamamatsu University School of Medicine, Osaka University, Kanazawa University, Chiba University, and University of Fukui, Osaka, Japan
- Research Center for Child Mental Development, University of Fukui, Fukui, Japan
- Department of Nursing, Faculty of Health Science, Fukui Health Science University, Fukui, Japan
| | - Takaharu Hirai
- Department of Psychiatric and Mental Health Nursing, School of Nursing, University of Fukui, Fukui, Japan
| | | | - Kenji J. Tsuchiya
- Research Center for Child Mental Development, Hamamatsu University School of Medicine, Shizuoka, Japan
| | - Hideo Matsuzaki
- Department of Functional Brain Activities, United Graduate School of Child Development, Hamamatsu University School of Medicine, Osaka University, Kanazawa University, Chiba University, and University of Fukui, Osaka, Japan
- Research Center for Child Mental Development, University of Fukui, Fukui, Japan
- Life Science Innovation Center, University of Fukui, Fukui, Japan
- *Correspondence: Hideo Matsuzaki,
| |
Collapse
|
3
|
Wang Y, Wagner KM, Morisseau C, Hammock BD. Inhibition of the Soluble Epoxide Hydrolase as an Analgesic Strategy: A Review of Preclinical Evidence. J Pain Res 2021; 14:61-72. [PMID: 33488116 PMCID: PMC7814236 DOI: 10.2147/jpr.s241893] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 12/08/2020] [Indexed: 12/16/2022] Open
Abstract
Chronic pain is a complicated condition which causes substantial physical, emotional, and financial impacts on individuals and society. However, due to high cost, lack of efficacy and safety problems, current treatments are insufficient. There is a clear unmet medical need for safe, nonaddictive and effective therapies in the management of pain. Epoxy-fatty acids (EpFAs), which are natural signaling molecules, play key roles in mediation of both inflammatory and neuropathic pain sensation. However, their molecular mechanisms of action remain largely unknown. Soluble epoxide hydrolase (sEH) rapidly converts EpFAs into less bioactive fatty acid diols in vivo; therefore, inhibition of sEH is an emerging therapeutic target to enhance the beneficial effect of natural EpFAs. In this review, we will discuss sEH inhibition as an analgesic strategy for pain management and the underlying molecular mechanisms.
Collapse
Affiliation(s)
- Yuxin Wang
- Department of Entomology and Nematology, UC Davis Comprehensive Cancer Center, University of California Davis, Davis, CA 95616, USA
| | - Karen M Wagner
- Department of Entomology and Nematology, UC Davis Comprehensive Cancer Center, University of California Davis, Davis, CA 95616, USA
| | - Christophe Morisseau
- Department of Entomology and Nematology, UC Davis Comprehensive Cancer Center, University of California Davis, Davis, CA 95616, USA
| | - Bruce D Hammock
- Department of Entomology and Nematology, UC Davis Comprehensive Cancer Center, University of California Davis, Davis, CA 95616, USA
| |
Collapse
|
4
|
Hashimoto K. Role of Soluble Epoxide Hydrolase in Metabolism of PUFAs in Psychiatric and Neurological Disorders. Front Pharmacol 2019; 10:36. [PMID: 30761004 PMCID: PMC6363819 DOI: 10.3389/fphar.2019.00036] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 01/14/2019] [Indexed: 12/16/2022] Open
Abstract
Inflammation plays a key role in the pathogenesis of a number of psychiatric and neurological disorders. Soluble epoxide hydrolases (sEH), enzymes present in all living organisms, metabolize epoxy fatty acids (EpFAs) to corresponding 1,2-diols by the addition of a molecule of water. Accumulating evidence suggests that sEH in the metabolism of polyunsaturated fatty acids (PUFAs) plays a key role in inflammation. Preclinical studies demonstrated that protein expression of sEH in the prefrontal cortex, striatum, and hippocampus from mice with depression-like phenotype was higher than control mice. Furthermore, protein expression of sEH in the parietal cortex from patients with major depressive disorder was higher than controls. Interestingly, Ephx2 knock-out (KO) mice exhibit stress resilience after chronic social defeat stress. Furthermore, the sEH inhibitors have antidepressant effects in animal models of depression. In addition, pharmacological inhibition or gene KO of sEH protected against dopaminergic neurotoxicity in the striatum after repeated administration of MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) in an animal model of Parkinson’s disease (PD). Protein expression of sEH in the striatum from MPTP-treated mice was higher than control mice. A number of studies using postmortem brain samples showed that the deposition of protein aggregates of α-synuclein, termed Lewy bodies, is evident in multiple brain regions of patients from PD and dementia with Lewy bodies (DLB). Moreover, the expression of the sEH protein in the striatum from patients with DLB was significantly higher compared with controls. Interestingly, there was a positive correlation between sEH expression and the ratio of phosphorylated α-synuclein to α-synuclein in the striatum. In the review, the author discusses the role of sEH in the metabolism of PUFAs in inflammation-related psychiatric and neurological disorders.
Collapse
Affiliation(s)
- Kenji Hashimoto
- Division of Clinical Neuroscience, Center for Forensic Mental Health, Chiba University, Chiba, Japan
| |
Collapse
|
5
|
Cinelli MA, Yang J, Scharmen A, Woodman J, Karchalla LM, Lee KSS. Enzymatic synthesis and chemical inversion provide both enantiomers of bioactive epoxydocosapentaenoic acids. J Lipid Res 2018; 59:2237-2252. [PMID: 30209076 PMCID: PMC6210906 DOI: 10.1194/jlr.d089136] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 09/12/2018] [Indexed: 11/20/2022] Open
Abstract
Epoxy PUFAs are endogenous cytochrome P450 (P450) metabolites of dietary PUFAs. Although these metabolites exert numerous biological effects, attempts to study their complex biology have been hampered by difficulty in obtaining the epoxides as pure regioisomers and enantiomers. To remedy this, we synthesized 19,20- and 16,17-epoxydocosapentaenoic acids (EDPs) (the two most abundant EDPs in vivo) by epoxidation of DHA with WT and the mutant (F87V) P450 enzyme BM3 from Bacillus megaterium WT epoxidation yielded a 4:1 mixture of 19,20:16,17-EDP exclusively as (S,R) enantiomers. Epoxidation with the mutant (F87V) yielded a 1.6:1 mixture of 19,20:16,17-EDP; the 19,20-EDP fraction was ∼9:1 (S,R):(R,S), but the 16,17-EDP was exclusively the (S,R) enantiomer. To access the (R,S) enantiomers of these EDPs, we used a short (four-step) chemical inversion sequence, which utilizes 2-(phenylthio)ethanol as the epoxide-opening nucleophile, followed by mesylation of the resulting alcohol, oxidation of the thioether moiety, and base-catalyzed elimination. This short synthesis cleanly converts the (S,R)-epoxide to the (R,S)-epoxide without loss of enantiopurity. This method, also applicable to eicosapentaenoic acid and arachidonic acid, provides a simple, cost-effective procedure for accessing larger amounts of these metabolites.
Collapse
Affiliation(s)
- Maris A Cinelli
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824
| | - Jun Yang
- Department of Entomology and Nematology University of California at Davis, Davis, CA 95616
- UCD Comprehensive Cancer Center, University of California at Davis, Davis, CA 95616
| | - Amy Scharmen
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824
| | - Joey Woodman
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824
| | - Lalitha M Karchalla
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824
| | - Kin Sing Stephen Lee
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824
| |
Collapse
|
6
|
Maddipati KR, Romero R, Chaiworapongsa T, Chaemsaithong P, Zhou SL, Xu Z, Tarca AL, Kusanovic JP, Gomez R, Docheva N, Honn KV. Clinical chorioamnionitis at term: the amniotic fluid fatty acyl lipidome. J Lipid Res 2016; 57:1906-1916. [PMID: 27538821 DOI: 10.1194/jlr.p069096] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Indexed: 12/31/2022] Open
Abstract
Clinical chorioamnionitis at term (TCC) is the most common obstetrical infliction diagnosed in labor and delivery units worldwide and is associated with a substantial increase in maternal and neonatal morbidity and mortality. This obstetrical complication is a heterogeneous condition, as only half of patients have detectable microorganisms in the amniotic cavity. Because bioactive lipids play a key role in the initiation and resolution of an inflammatory response, we aimed to characterize the amniotic fluid lipidome in patients with TCC. We studied the amniotic fluid of patients in the following groups: 1) spontaneous labor at term without clinical chorioamnionitis (TLB) and 2) spontaneous labor at term with clinical chorioamnionitis (TCC). The TCC group was subdivided into a) those with microbial invasion of the amniotic cavity (TCC-MIAC) and b) those without microbial invasion of the amniotic cavity (TCC-noMIAC). The amniotic fluid concentration of proinflammatory lipid mediators did not differ between patients in TLB with TCC. In contrast, concentration of lipids with anti-inflammatory/proresolution properties was significantly lower in all patients with TCC than in those with TLB. These results suggest that while proinflammatory lipid mediators are involved in infection-driven intra-amniotic inflammation, a relative deficiency of anti-inflammatory/proresolution lipid mediator biosynthesis is a characteristic of TCC.
Collapse
Affiliation(s)
- Krishna Rao Maddipati
- Bioactive Lipids Research Program, Department of Pathology, Wayne State University School of Medicine, Detroit, MI; Lipidomics Core Facility, Wayne State University School of Medicine, Detroit, MI.
| | - Roberto Romero
- Perinatology Research Branch, Program for Perinatal Research and Obstetrics, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Department of Health and Human Services, Bethesda, MD, and Detroit, MI; Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, MI; Department of Epidemiology and Biostatistics, Michigan State University, East Lansing, MI; Center for Molecular Medicine and Genetics, Wayne State University, Detroit, MI
| | - Tinnakorn Chaiworapongsa
- Perinatology Research Branch, Program for Perinatal Research and Obstetrics, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Department of Health and Human Services, Bethesda, MD, and Detroit, MI; Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, MI
| | - Piya Chaemsaithong
- Perinatology Research Branch, Program for Perinatal Research and Obstetrics, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Department of Health and Human Services, Bethesda, MD, and Detroit, MI; Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, MI
| | - Sen-Lin Zhou
- Bioactive Lipids Research Program, Department of Pathology, Wayne State University School of Medicine, Detroit, MI; Lipidomics Core Facility, Wayne State University School of Medicine, Detroit, MI
| | - Zhonghui Xu
- Perinatology Research Branch, Program for Perinatal Research and Obstetrics, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Department of Health and Human Services, Bethesda, MD, and Detroit, MI
| | - Adi L Tarca
- Perinatology Research Branch, Program for Perinatal Research and Obstetrics, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Department of Health and Human Services, Bethesda, MD, and Detroit, MI; Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, MI; Department of Computer Science, Wayne State University, Detroit, MI
| | - Juan Pedro Kusanovic
- Perinatology Research Branch, Program for Perinatal Research and Obstetrics, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Department of Health and Human Services, Bethesda, MD, and Detroit, MI; Center for Research and Innovation in Maternal-Fetal Medicine (CIMAF), Department of Obstetrics and Gynecology, Sótero del Río Hospital, Santiago, Chile; Division of Obstetrics and Gynecology, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Ricardo Gomez
- Division of Obstetrics and Gynecology, Pontificia Universidad Católica de Chile, Santiago, Chile; Center for Perinatal Diagnosis (CEDIP), Research and Academic Innovations, Hospital Clínico La Florida, Santiago, Chile
| | - Nikolina Docheva
- Perinatology Research Branch, Program for Perinatal Research and Obstetrics, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Department of Health and Human Services, Bethesda, MD, and Detroit, MI; Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, MI
| | - Kenneth V Honn
- Bioactive Lipids Research Program, Department of Pathology, Wayne State University School of Medicine, Detroit, MI
| |
Collapse
|
7
|
Maddipati KR, Romero R, Chaiworapongsa T, Zhou SL, Xu Z, Tarca AL, Kusanovic JP, Munoz H, Honn KV. Eicosanomic profiling reveals dominance of the epoxygenase pathway in human amniotic fluid at term in spontaneous labor. FASEB J 2014; 28:4835-46. [PMID: 25059230 DOI: 10.1096/fj.14-254383] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Lipid mediators play an important role in reproductive biology, especially, in parturition. Enhanced biosynthesis of eicosanoids, such as prostaglandin E2 (PGE2) and PGF2α, precedes the onset of labor as a result of increased expression of inducible cyclooxygenase 2 (COX-2) in placental tissues. Metabolism of arachidonic acid results in bioactive lipid mediators beyond prostaglandins that could significantly influence myometrial activity. Therefore, an unbiased lipidomic approach was used to profile the arachidonic acid metabolome of amniotic fluid. In this study, liquid chromatography-mass spectrometry was used for the first time to quantitate these metabolites in human amniotic fluid by comparing patients at midtrimester, at term but not in labor, and at term and in spontaneous labor. In addition to exposing novel aspects of COX pathway metabolism, this lipidomic study revealed a dramatic increase in epoxygenase- and lipoxygenase-pathway-derived lipid mediators in spontaneous labor with remarkable product selectivity. Despite their recognition as anti-inflammatory lipid mediators and regulators of ion channels, little is known about the epoxygenase pathway in labor. Epoxygenase pathway metabolites are established regulators of vascular homeostasis in cardiovascular and renal physiology. Their presence as the dominant lipid mediators in spontaneous labor at term portends a yet undiscovered physiological function in parturition.
Collapse
Affiliation(s)
- Krishna Rao Maddipati
- Bioactive Lipids Research Program, Department of Pathology, Lipidomics Core Facility, and
| | - Roberto Romero
- Perinatology Research Branch, Program for Perinatal Research and Obstetrics, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA; Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, Michigan, USA; Department of Epidemiology, Michigan State University, East Lansing, Michigan, USA
| | - Tinnakorn Chaiworapongsa
- Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, Michigan, USA; Perinatology Research Branch, Program for Perinatal Research and Obstetrics, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Sen-Lin Zhou
- Bioactive Lipids Research Program, Department of Pathology, Lipidomics Core Facility, and
| | - Zhonghui Xu
- Department of Computer Science, Wayne State University, Detroit, Michigan, USA
| | - Adi L Tarca
- Department of Computer Science, Wayne State University, Detroit, Michigan, USA
| | - Juan Pedro Kusanovic
- Perinatology Research Branch, Program for Perinatal Research and Obstetrics, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA; Department of Obstetrics and Gynecology, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile; Sótero del Río Hospital, Santiago, Chile; and
| | | | - Kenneth V Honn
- Bioactive Lipids Research Program, Department of Pathology
| |
Collapse
|
8
|
Wagner K, Yang J, Inceoglu B, Hammock BD. Soluble epoxide hydrolase inhibition is antinociceptive in a mouse model of diabetic neuropathy. J Pain 2014; 15:907-14. [PMID: 24924124 DOI: 10.1016/j.jpain.2014.05.008] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 05/10/2014] [Accepted: 05/28/2014] [Indexed: 01/10/2023]
Abstract
UNLABELLED Neuropathic pain is currently an insufficiently treated clinical condition. There remains a critical need for efficacious therapies without severe side effects to treat the uniquely persistent and tonic pain of neuropathy. Inhibitors of the soluble epoxide hydrolase (sEH) enzyme that stabilize endogenous epoxy fatty acids have demonstrated antihyperalgesia in clinical chronic inflammatory pain and modeled neuropathic pain. Recently, the conditioned place preference assay has been used to evaluate the tonic nature of neuropathy in several animal models. The current experiments use the conditioned place preference assay alongside withdrawal thresholds to investigate the antihyperalgesic efficacy of sEH inhibitors in a murine model of diabetic neuropathy. Here, the sEH inhibitor trans-4-[4-(3-trifluoromethoxyphenyl-1-ureido)-cyclohexyloxy]-benzoic acid (t-TUCB) at 10 mg/kg induced a robust place preference in diabetic neuropathic mice representative of pain relief. Importantly, this effect was absent both in control mice and in sEH-knockout mice at the same dose, indicating that t-TUCB is not positively reinforcing or rewarding. When compared to gabapentin, t-TUCB elicited a similar degree of withdrawal threshold improvement without the same degree of spontaneous locomotion decline in neuropathic mice. Overall, these experiments show that inhibiting the sEH enzyme attenuates chronic pain and offers an alternative to current side-effect-limited therapies to meet this clinical need. PERSPECTIVE These experiments demonstrate antihyperalgesia in a murine chronic pain model mediated by inhibiting the sEH enzyme. The results of this study indicate that inhibiting the sEH is a promising alternative for blocking chronic pain.
Collapse
|