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Grabauskas G. Important Study Adds to Understanding of the Pathophysiology of Visceral Hypersensitivity but Raises More Questions Than it Answers. Gastroenterology 2016; 150:777. [PMID: 26827799 DOI: 10.1053/j.gastro.2015.09.052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 09/22/2015] [Indexed: 12/02/2022]
Affiliation(s)
- Gintautas Grabauskas
- Internal Medicine, Gastroenterology Division, University of Michigan, Ann Arbor, Michigan
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53
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Nociceptor Sensitization Depends on Age and Pain Chronicity(1,2,3). eNeuro 2016; 3:eN-NWR-0115-15. [PMID: 26866058 PMCID: PMC4745182 DOI: 10.1523/eneuro.0115-15.2015] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 12/16/2015] [Accepted: 12/17/2015] [Indexed: 01/18/2023] Open
Abstract
Peripheral inflammation causes mechanical pain behavior and increased action potential firing. However, most studies examine inflammatory pain at acute, rather than chronic time points, despite the greater burden of chronic pain on patient populations, especially aged individuals. Furthermore, there is disagreement in the field about whether primary afferents contribute to chronic pain. Therefore, we sought to evaluate the contribution of nociceptor activity to the generation of pain behaviors during the acute and chronic phases of inflammation in both young and aged mice. We found that both young (2 months old) and aged (>18 months old) mice exhibited prominent pain behaviors during both acute (2 day) and chronic (8 week) inflammation. However, young mice exhibited greater behavioral sensitization to mechanical stimuli than their aged counterparts. Teased fiber recordings in young animals revealed a twofold mechanical sensitization in C fibers during acute inflammation, but an unexpected twofold reduction in firing during chronic inflammation. Responsiveness to capsaicin and mechanical responsiveness of A-mechanonociceptor (AM) fibers were also reduced chronically. Importantly, this lack of sensitization in afferent firing during chronic inflammation occurred even as these inflamed mice exhibited continued behavioral sensitization. Interestingly, C fibers from inflamed aged animals showed no change in mechanical firing compared with controls during either the acute or chronic inflammatory phases, despite strong behavioral sensitization to mechanical stimuli at these time points. These results reveal the following two important findings: (1) nociceptor sensitization to mechanical stimulation depends on age and the chronicity of injury; and (2) maintenance of chronic inflammatory pain does not rely on enhanced peripheral drive.
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Blöcher R, Lamers C, Wittmann SK, Merk D, Hartmann M, Weizel L, Diehl O, Brüggerhoff A, Boß M, Kaiser A, Schader T, Göbel T, Grundmann M, Angioni C, Heering J, Geisslinger G, Wurglics M, Kostenis E, Brüne B, Steinhilber D, Schubert-Zsilavecz M, Kahnt AS, Proschak E. N-Benzylbenzamides: A Novel Merged Scaffold for Orally Available Dual Soluble Epoxide Hydrolase/Peroxisome Proliferator-Activated Receptor γ Modulators. J Med Chem 2015; 59:61-81. [PMID: 26595749 DOI: 10.1021/acs.jmedchem.5b01239] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Metabolic syndrome (MetS) is a multifactorial disease cluster that consists of dyslipidemia, cardiovascular disease, type 2 diabetes mellitus, and obesity. MetS patients are strongly exposed to polypharmacy; however, the number of pharmacological compounds required for MetS treatment can be reduced by the application of multitarget compounds. This study describes the design of dual-target ligands that target soluble epoxide hydrolase (sEH) and the peroxisome proliferator-activated receptor type γ (PPARγ). Simultaneous modulation of sEH and PPARγ can improve diabetic conditions and hypertension at once. N-Benzylbenzamide derivatives were determined to fit a merged sEH/PPARγ pharmacophore, and structure-activity relationship studies were performed on both targets, resulting in a submicromolar (sEH IC50 = 0.3 μM/PPARγ EC50 = 0.3 μM) modulator 14c. In vitro and in vivo evaluations revealed good ADME properties qualifying 14c as a pharmacological tool compound for long-term animal models of MetS.
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Affiliation(s)
- René Blöcher
- Institute of Pharmaceutical Chemistry, Goethe-University Frankfurt , Max-von-Laue-Strasse 9, D-60438 Frankfurt am Main, Germany
| | - Christina Lamers
- Institute of Pharmaceutical Chemistry, Goethe-University Frankfurt , Max-von-Laue-Strasse 9, D-60438 Frankfurt am Main, Germany
| | - Sandra K Wittmann
- Institute of Pharmaceutical Chemistry, Goethe-University Frankfurt , Max-von-Laue-Strasse 9, D-60438 Frankfurt am Main, Germany
| | - Daniel Merk
- Institute of Pharmaceutical Chemistry, Goethe-University Frankfurt , Max-von-Laue-Strasse 9, D-60438 Frankfurt am Main, Germany
| | - Markus Hartmann
- Institute of Pharmaceutical Chemistry, Goethe-University Frankfurt , Max-von-Laue-Strasse 9, D-60438 Frankfurt am Main, Germany
| | - Lilia Weizel
- Institute of Pharmaceutical Chemistry, Goethe-University Frankfurt , Max-von-Laue-Strasse 9, D-60438 Frankfurt am Main, Germany
| | - Olaf Diehl
- Institute of Pharmaceutical Chemistry, Goethe-University Frankfurt , Max-von-Laue-Strasse 9, D-60438 Frankfurt am Main, Germany
| | - Astrid Brüggerhoff
- Institute of Pharmaceutical Chemistry, Goethe-University Frankfurt , Max-von-Laue-Strasse 9, D-60438 Frankfurt am Main, Germany
| | - Marcel Boß
- Institute of Biochemistry I, Goethe-University Frankfurt , Theodor-Stern-Kai 7, D-60590 Frankfurt am Main, Germany
| | - Astrid Kaiser
- Institute of Pharmaceutical Chemistry, Goethe-University Frankfurt , Max-von-Laue-Strasse 9, D-60438 Frankfurt am Main, Germany
| | - Tim Schader
- Institute of Pharmaceutical Chemistry, Goethe-University Frankfurt , Max-von-Laue-Strasse 9, D-60438 Frankfurt am Main, Germany
| | - Tamara Göbel
- Institute of Pharmaceutical Chemistry, Goethe-University Frankfurt , Max-von-Laue-Strasse 9, D-60438 Frankfurt am Main, Germany
| | - Manuel Grundmann
- Institute of Pharmaceutical Biology, Rheinische Friedrich-Wilhelms-Universität Bonn , Nussallee 6, D-53115 Bonn, Germany
| | - Carlo Angioni
- Institute of Clinical Pharmacology, Goethe-University Frankfurt , Theodor-Stern-Kai 7, D-60590 Frankfurt am Main, Germany
| | - Jan Heering
- Project Group Translational Medicine and Pharmacology TMP, Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Theodor-Stern-Kai 7, D-60590 Frankfurt am Main, Germany
| | - Gerd Geisslinger
- Institute of Clinical Pharmacology, Goethe-University Frankfurt , Theodor-Stern-Kai 7, D-60590 Frankfurt am Main, Germany
| | - Mario Wurglics
- Institute of Pharmaceutical Chemistry, Goethe-University Frankfurt , Max-von-Laue-Strasse 9, D-60438 Frankfurt am Main, Germany
| | - Evi Kostenis
- Institute of Pharmaceutical Biology, Rheinische Friedrich-Wilhelms-Universität Bonn , Nussallee 6, D-53115 Bonn, Germany
| | - Bernhard Brüne
- Institute of Biochemistry I, Goethe-University Frankfurt , Theodor-Stern-Kai 7, D-60590 Frankfurt am Main, Germany
| | - Dieter Steinhilber
- Institute of Pharmaceutical Chemistry, Goethe-University Frankfurt , Max-von-Laue-Strasse 9, D-60438 Frankfurt am Main, Germany
| | - Manfred Schubert-Zsilavecz
- Institute of Pharmaceutical Chemistry, Goethe-University Frankfurt , Max-von-Laue-Strasse 9, D-60438 Frankfurt am Main, Germany
| | - Astrid S Kahnt
- Institute of Pharmaceutical Chemistry, Goethe-University Frankfurt , Max-von-Laue-Strasse 9, D-60438 Frankfurt am Main, Germany
| | - Ewgenij Proschak
- Institute of Pharmaceutical Chemistry, Goethe-University Frankfurt , Max-von-Laue-Strasse 9, D-60438 Frankfurt am Main, Germany
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Goswami SK, Inceoglu B, Yang J, Wan D, Kodani SD, da Silva CAT, Morisseau C, Hammock BD. Omeprazole increases the efficacy of a soluble epoxide hydrolase inhibitor in a PGE₂ induced pain model. Toxicol Appl Pharmacol 2015; 289:419-27. [PMID: 26522832 DOI: 10.1016/j.taap.2015.10.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 10/21/2015] [Accepted: 10/27/2015] [Indexed: 12/26/2022]
Abstract
Epoxyeicosatrienoic acids (EETs) are potent endogenous analgesic metabolites produced from arachidonic acid by cytochrome P450s (P450s). Metabolism of EETs by soluble epoxide hydrolase (sEH) reduces their activity, while their stabilization by sEH inhibition decreases both inflammatory and neuropathic pain. Here, we tested the complementary hypothesis that increasing the level of EETs through induction of P450s by omeprazole (OME), can influence pain related signaling by itself, and potentiate the anti-hyperalgesic effect of sEH inhibitor. Rats were treated with OME (100mg/kg/day, p.o., 7 days), sEH inhibitor TPPU (3mg/kg/day, p.o.) and OME (100mg/kg/day, p.o., 7 days)+TPPU (3mg/kg/day, p.o., last 3 days of OME dose) dissolved in vehicle PEG400, and their effect on hyperalgesia (increased sensitivity to pain) induced by PGE2 was monitored. While OME treatment by itself exhibited variable effects on PGE2 induced hyperalgesia, it strongly potentiated the effect of TPPU in the same assay. The significant decrease in pain with OME+TPPU treatment correlated with the increased levels of EETs in plasma and increased activities of P450 1A1 and P450 1A2 in liver microsomes. The results show that reducing catabolism of EETs with a sEH inhibitor yielded a stronger analgesic effect than increasing generation of EETs by OME, and combination of both yielded the strongest pain reducing effect under the condition of this study.
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Affiliation(s)
- Sumanta Kumar Goswami
- Department of Entomology and Nematology, UC Davis Comprehensive Cancer Center, University of California, Davis, CA, USA
| | - Bora Inceoglu
- Department of Entomology and Nematology, UC Davis Comprehensive Cancer Center, University of California, Davis, CA, USA
| | - Jun Yang
- Department of Entomology and Nematology, UC Davis Comprehensive Cancer Center, University of California, Davis, CA, USA
| | - Debin Wan
- Department of Entomology and Nematology, UC Davis Comprehensive Cancer Center, University of California, Davis, CA, USA
| | - Sean D Kodani
- Department of Entomology and Nematology, UC Davis Comprehensive Cancer Center, University of California, Davis, CA, USA
| | - Carlos Antonio Trindade da Silva
- Department of Entomology and Nematology, UC Davis Comprehensive Cancer Center, University of California, Davis, CA, USA; Department of Genetics and Biochemistry, Federal University of Uberlandia, MG, Brazil
| | - Christophe Morisseau
- Department of Entomology and Nematology, UC Davis Comprehensive Cancer Center, University of California, Davis, CA, USA
| | - Bruce D Hammock
- Department of Entomology and Nematology, UC Davis Comprehensive Cancer Center, University of California, Davis, CA, USA.
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56
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Wu HF, Yen HJ, Huang CC, Lee YC, Wu SZ, Lee TS, Lin HC. Soluble epoxide hydrolase inhibitor enhances synaptic neurotransmission and plasticity in mouse prefrontal cortex. J Biomed Sci 2015; 22:94. [PMID: 26494028 PMCID: PMC4618874 DOI: 10.1186/s12929-015-0202-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2015] [Accepted: 10/09/2015] [Indexed: 12/29/2022] Open
Abstract
Background The soluble epoxide hydrolase (sEH) is an important enzyme chiefly involved in the metabolism of fatty acid signaling molecules termed epoxyeicosatrienoic acids (EETs). sEH inhibition (sEHI) has proven to be protective against experimental cerebral ischemia, and it is emerging as a therapeutic target for prevention and treatment of ischemic stroke. However, the role of sEH on synaptic function in the central nervous system is still largely unknown. This study aimed to test whether sEH C-terminal epoxide hydrolase inhibitor, 12-(3-adamantan-1-yl-ureido) dodecanoic acid (AUDA) affects basal synaptic transmission and synaptic plasticity in the prefrontal cortex area (PFC). Whole cell and extracellular recording examined the miniature excitatory postsynaptic currents (mEPSCs) and field excitatory postsynaptic potentials (fEPSPs); Western Blotting determined the protein levels of glutamate receptors and ERK phosphorylation in acute medial PFC slices. Results Application of the sEH C-terminal epoxide hydrolase inhibitor, AUDA significantly increased the amplitude of mEPSCs and fEPSPs in prefrontal cortex neurons, while additionally enhancing long term potentiation (LTP). Western Blotting demonstrated that AUDA treatment increased the expression of the N-methyl-D-aspartate receptor (NMDA) subunits NR1, NR2A, NR2B; the α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunits GluR1, GluR2, and ERK phosphorylation. Conclusions Inhibition of sEH induced an enhancement of PFC neuronal synaptic neurotransmission. This enhancement of synaptic neurotransmission is associated with an enhanced postsynaptic glutamatergic receptor and postsynaptic glutamatergic receptor mediated synaptic LTP. LTP is enhanced via ERK phosphorylation resulting from the delivery of glutamate receptors into the PFC by post-synapse by treatment with AUDA. These findings provide a possible link between synaptic function and memory processes.
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Affiliation(s)
- Han-Fang Wu
- Institute and Department of Physiology, School of Medicine, National Yang-Ming University, Taipei, 11221, Taiwan
| | - Hsin-Ju Yen
- Institute and Department of Physiology, School of Medicine, National Yang-Ming University, Taipei, 11221, Taiwan
| | - Chi-Chen Huang
- Ph.D. Program for Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei, 11031, Taiwan.,Center for Neurotrauma and Neuroregeneration, Taipei Medical University, Taipei, 11031, Taiwan
| | - Yi-Chao Lee
- Ph.D. Program for Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei, 11031, Taiwan.,Center for Neurotrauma and Neuroregeneration, Taipei Medical University, Taipei, 11031, Taiwan
| | - Su-Zhen Wu
- Department of Anesthesiology, Chi-Mei Medical Center, Tainan, Taiwan
| | - Tzong-Shyuan Lee
- Institute and Department of Physiology, School of Medicine, National Yang-Ming University, Taipei, 11221, Taiwan.,Brain Research Center, National Yang-Ming University, Taipei, 11221, Taiwan
| | - Hui-Ching Lin
- Institute and Department of Physiology, School of Medicine, National Yang-Ming University, Taipei, 11221, Taiwan. .,Ph.D. Program for Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei, 11031, Taiwan. .,Brain Research Center, National Yang-Ming University, Taipei, 11221, Taiwan.
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57
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Niederberger E, Kuner R, Geißlinger G. [Pharmacological aspects of pain research in Germany]. Schmerz 2015; 29:531-8. [PMID: 26294077 DOI: 10.1007/s00482-015-0042-0] [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] [Indexed: 11/25/2022]
Abstract
In spite of several approved analgesics, the therapy of pain still constitutes a challenge due to the fact that the drugs do not exert sufficient efficacy or are associated with severe side effects. Therefore, the development of new and improved painkillers is still of great importance. A number of highly qualified scientists in Germany are investigating signal transduction pathways in pain, effectivity of new drugs and the so far incompletely investigated mechanisms of well-known analgesics in preclinical and clinical studies. The highlights of pharmacological pain research in Germany are summarized in this article.
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Affiliation(s)
- E Niederberger
- pharmazentrum frankfurt/ZAFES, Institut für Klinische Pharmakologie, Klinikum der Goethe-Universität Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Deutschland
| | - R Kuner
- Pharmakologisches Institut, Universität Heidelberg, Im Neuenheimer Feld 584, 69120, Heidelberg, Deutschland
| | - G Geißlinger
- pharmazentrum frankfurt/ZAFES, Institut für Klinische Pharmakologie, Klinikum der Goethe-Universität Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Deutschland.
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58
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Cenac N, Bautzova T, Le Faouder P, Veldhuis NA, Poole DP, Rolland C, Bertrand J, Liedtke W, Dubourdeau M, Bertrand-Michel J, Zecchi L, Stanghellini V, Bunnett NW, Barbara G, Vergnolle N. Quantification and Potential Functions of Endogenous Agonists of Transient Receptor Potential Channels in Patients With Irritable Bowel Syndrome. Gastroenterology 2015; 149:433-44.e7. [PMID: 25911511 DOI: 10.1053/j.gastro.2015.04.011] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 02/05/2015] [Accepted: 04/04/2015] [Indexed: 12/02/2022]
Abstract
BACKGROUND & AIMS In mice, activation of the transient receptor potential cation channels (TRP) TRPV1, TRPV4, and TRPA1 causes visceral hypersensitivity. These receptors and their agonists might be involved in development of irritable bowel syndrome (IBS). We investigated whether polyunsaturated fatty acid (PUFA) metabolites, which activate TRPs, are present in colon tissues from patients with IBS and act as endogenous agonists to induce hypersensitivity. METHODS We analyzed colon biopsy samples from 40 patients with IBS (IBS biopsies) and 11 healthy individuals undergoing colorectal cancer screening (controls), collected during colonoscopy at the University of Bologna, Italy. Levels of the PUFA metabolites that activate TRPV1 (12-hydroperoxyeicosatetraenoic acid, 15-hydroxyeicosatetraenoic acid, 5-hydroxyeicosatetraenoic acid, and leukotriene B4), TRPV4 (5,6-epoxyeicosatrienoic acid [EET] and 8,9-EET), and TRPA1 (PGA1, 8-iso-prostaglandin A2, and 15-deoxy-Δ-prostaglandin J2) were measured in biopsies and their supernatants using liquid chromatography and tandem mass spectrometry; we also measured levels of the PUFA metabolites prostaglandin E2 (PGE2) and resolvins. C57Bl6 mice were given intrathecal injections of small interfering RNAs to reduce levels of TRPV4, or control small interfering RNAs, along with colonic injections of biopsy supernatants; visceral hypersensitivity was measured based on response to colorectal distension. Mouse sensory neurons were cultured and incubated with biopsy supernatants and lipids extracted from biopsies or colons of mice. Immunohistochemistry was used to detect TRPV4 in human dorsal root ganglia samples (from the National Disease Research Interchange). RESULTS Levels of the TRPV4 agonist 5,6-EET, but not levels of TRPV1 or TRPA1 agonists, were increased in IBS biopsies compared with controls; increases correlated with pain and bloating scores. Supernatants from IBS biopsies, but not from controls, induced visceral hypersensitivity in mice. Small interfering RNA knockdown of TRPV4 in mouse primary afferent neurons inhibited the hypersensitivity caused by supernatants from IBS biopsies. Levels of 5,6-EET and 15-HETE were increased in colons of mice with, but not without, visceral hypersensitivity. PUFA metabolites extracted from IBS biopsies or colons of mice with visceral hypersensitivity activated mouse sensory neurons in vitro, by activating TRPV4. Mouse sensory neurons exposed to supernatants from IBS biopsies produced 5,6-EET via a mechanism that involved the proteinase-activated receptor-2 and cytochrome epoxygenase. In human dorsal root ganglia, TPV4 was expressed by 35% of neurons. CONCLUSIONS Colon tissues from patients with IBS have increased levels of specific PUFA metabolites. These stimulate sensory neurons from mice and generate visceral hypersensitivity via activation of TRPV4.
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Affiliation(s)
- Nicolas Cenac
- Inserm, U1043, Toulouse, France; CNRS, U5282, Toulouse, France; Université de Toulouse, Université Paul Sabatier, Centre de Physiopathologie de Toulouse Purpan (CPTP), Toulouse, France
| | - Tereza Bautzova
- Inserm, U1043, Toulouse, France; CNRS, U5282, Toulouse, France; Université de Toulouse, Université Paul Sabatier, Centre de Physiopathologie de Toulouse Purpan (CPTP), Toulouse, France
| | - Pauline Le Faouder
- Inserm, U1043, Toulouse, France; CNRS, U5282, Toulouse, France; Université de Toulouse, Université Paul Sabatier, Centre de Physiopathologie de Toulouse Purpan (CPTP), Toulouse, France; Inserm U1048, Toulouse, France; Lipidomic Core Facility, Metatoul Platform, Université de Toulouse, Université Paul Sabatier, Toulouse, France
| | | | - Daniel P Poole
- Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia; Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Victoria, Australia
| | - Corinne Rolland
- Inserm, U1043, Toulouse, France; CNRS, U5282, Toulouse, France; Université de Toulouse, Université Paul Sabatier, Centre de Physiopathologie de Toulouse Purpan (CPTP), Toulouse, France
| | - Jessica Bertrand
- Inserm, U1043, Toulouse, France; CNRS, U5282, Toulouse, France; Université de Toulouse, Université Paul Sabatier, Centre de Physiopathologie de Toulouse Purpan (CPTP), Toulouse, France
| | - Wolfgang Liedtke
- Division of Neurology, Department of Medicine, Duke University Medical Center, Durham, North Carolina
| | | | - Justine Bertrand-Michel
- Inserm U1048, Toulouse, France; Lipidomic Core Facility, Metatoul Platform, Université de Toulouse, Université Paul Sabatier, Toulouse, France
| | - Lisa Zecchi
- Departments of Internal Medicine and Gastroenterology, University of Bologna, Bologna, Italy
| | - Vincenzo Stanghellini
- Departments of Internal Medicine and Gastroenterology, University of Bologna, Bologna, Italy
| | - Nigel W Bunnett
- Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia; Department of Pharmacology, The University of Melbourne, Parkville, Victoria, Australia
| | - Giovanni Barbara
- Departments of Internal Medicine and Gastroenterology, University of Bologna, Bologna, Italy
| | - Nathalie Vergnolle
- Inserm, U1043, Toulouse, France; CNRS, U5282, Toulouse, France; Université de Toulouse, Université Paul Sabatier, Centre de Physiopathologie de Toulouse Purpan (CPTP), Toulouse, France; University of Calgary, Department of Pharmacology and Physiology, Calgary, Alberta, Canada.
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Yaksh TL, Woller SA, Ramachandran R, Sorkin LS. The search for novel analgesics: targets and mechanisms. F1000PRIME REPORTS 2015; 7:56. [PMID: 26097729 PMCID: PMC4447049 DOI: 10.12703/p7-56] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The management of the pain state is of great therapeutic relevance to virtually every medical specialty. Failure to manage its expression has deleterious consequence to the well-being of the organism. An understanding of the complex biology of the mechanisms underlying the processing of nociceptive information provides an important pathway towards development of novel and robust therapeutics. Importantly, preclinical models have been of considerable use in determining the linkage between mechanism and the associated behaviorally defined pain state. This review seeks to provide an overview of current thinking targeting pain biology, the use of preclinical models and the development of novel pain therapeutics. Issues pertinent to the strengths and weaknesses of current development strategies for analgesics are considered.
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60
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Ruparel S, Bendele M, Wallace A, Green D. Released lipids regulate transient receptor potential channel (TRP)-dependent oral cancer pain. Mol Pain 2015; 11:30. [PMID: 26007300 PMCID: PMC4456056 DOI: 10.1186/s12990-015-0016-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 03/25/2015] [Indexed: 12/24/2022] Open
Abstract
Background Pain in the head neck area is an early symptom in oral cancer, supporting the hypothesis that cancer cells control the activities of surrounding nociceptors at the site of the tumor. Several reports implicate TRPV1 and TRPA1 in cancer pain, although there is a large gap in knowledge since the mechanisms for tumor-induced activation of these TRP receptors are unknown. Interestingly, TRP-active lipids such as linoleic acid, arachidonic acid, hydroxyoctadecadienoic acid and hydroxyeicosatetraenoic acid are significantly elevated in the saliva of oral cancer patients compared to normal patients, supporting a possible linkage between these lipids and oral cancer pain. We therefore hypothesize that oral squamous cell carcinomas release certain lipids that activate TRPV1 and/or TRPA1 on sensory neurons, contributing to the development of oral cancer pain. Methods Lipid extracts were made from conditioned media of three human oral squamous cell carcinoma (OSCC) cell lines as well as one normal human oral keratinocytes cell line. These were then injected intraplantarly into rat hindpaws to measure spontaneous nocifensive behavior, as well as thermal and mechanical allodynia. For interventional experiments, the animals were pretreated with AMG517 (TRPV1 antagonist) or HC030031 (TRPA1 antagonist) prior to extract injection. Results These studies demonstrate that lipids released from the three OSCC cell lines, but not the normal cell line, were capable of producing significant spontaneous nocifensive behaviors, as well as thermal and mechanical allodynia. Notably each of the cell lines produced a different magnitude of response for each of three behavioral assays. Importantly, pre-treatment with a TRPVI antagonist blocked lipid-mediated nocifensive and thermal hypersensitivity, but not mechanical hypersensitivity. In addition, pre-treatment with a TRPA1 antagonist only reversed thermal hypersensitivity without affecting lipid-induced nocifensive behavior or mechanical allodynia. Conclusions These data reveal a novel mechanism for cancer pain and provide strong direction for future studies evaluating the cellular mechanism regulating the TRP-active lipids by OSCC tumors.
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Affiliation(s)
- Shivani Ruparel
- Department of Endodontics, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, Texas, 78229, USA.
| | - Michelle Bendele
- Department of Endodontics, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, Texas, 78229, USA.
| | - Ashley Wallace
- Department of Neuroscience, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA.
| | - Dustin Green
- Department of Physiology, University of Texas Health Science Center at San Antonio, Texas, USA.
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Chen J, Hackos DH. TRPA1 as a drug target--promise and challenges. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2015; 388:451-63. [PMID: 25640188 PMCID: PMC4359712 DOI: 10.1007/s00210-015-1088-3] [Citation(s) in RCA: 121] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 01/12/2015] [Indexed: 12/25/2022]
Abstract
The transient receptor potential ankyrin 1 (TRPA1) channel is a nonselective cation channel belonging to the superfamily of transient receptor potential (TRP) channels. It is predominantly expressed in sensory neurons and serves as an irritant sensor for a plethora of electrophilic compounds. Recent studies suggest that TRPA1 is involved in pain, itch, and respiratory diseases, and TRPA1 antagonists have been actively pursued as therapeutic agents. Here, we review the recent progress, unsettled issues, and challenges in TRPA1 research and drug discovery.
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Affiliation(s)
- Jun Chen
- Department of Biochemical and Cellular Pharmacology, Genentech, South San Francisco, CA 94080 USA
| | - David H. Hackos
- Department of Neuroscience, Genentech, South San Francisco, CA 94080 USA
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62
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Taberner FJ, Fernández-Ballester G, Fernández-Carvajal A, Ferrer-Montiel A. TRP channels interaction with lipids and its implications in disease. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:1818-27. [PMID: 25838124 DOI: 10.1016/j.bbamem.2015.03.022] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Revised: 03/21/2015] [Accepted: 03/23/2015] [Indexed: 01/21/2023]
Abstract
Transient receptor potential (TRP) proteins are a family of ion channels central for sensory signaling. These receptors and, in particular, those involved in thermal sensing are also involved in pain signaling. Noteworthy, thermosensory receptors are polymodal ion channels that respond to both physical and chemical stimuli, thus integrating different environmental clues. In addition, their activity is modulated by algesic agents and lipidergic substances that are primarily released in pathological states. Lipids and lipid-like molecules have been found that can directly activate some thermosensory channels or modulate their activity by either potentiating or inhibiting it. To date, more than 50 endogenous lipids that can regulate TRP channel activity in sensory neurons have been described, thus representing the majority of known endogenous TRP channel modulators. Lipid modulators of TRP channels comprise lipids from a variety of metabolic pathways, including metabolites of the cyclooxygenase, lipoxygenase and cytochrome-P450 pathways, phospholipids and lysophospholipids. Therefore, TRP-channels are able to integrate and interpret incoming signals from the different metabolic lipid pathways. Taken together, the large number of lipids that can activate, sensitize or inhibit neuronal TRP-channels highlights the pivotal role of these molecules in sensory biology as well as in pain transduction and perception. This article is part of a Special Issue entitled: Lipid-protein interactions. Guest Editors: Amitabha Chattopadhyay and Jean-Marie Ruysschaert.
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Affiliation(s)
- Francisco J Taberner
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Alicante, Spain
| | | | | | - Antonio Ferrer-Montiel
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Alicante, Spain.
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63
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Mickle AD, Shepherd AJ, Mohapatra DP. Sensory TRP channels: the key transducers of nociception and pain. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 131:73-118. [PMID: 25744671 DOI: 10.1016/bs.pmbts.2015.01.002] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Peripheral detection of nociceptive and painful stimuli by sensory neurons involves a complex repertoire of molecular detectors and/or transducers on distinct subsets of nerve fibers. The majority of such molecular detectors/transducers belong to the transient receptor potential (TRP) family of cation channels, which comprise both specific receptors for distinct nociceptive stimuli, as well as for multiple stimuli. This chapter discusses the classification, distribution, and functional properties of individual TRP channel types that have been implicated in various nociceptive and/or painful conditions.
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Affiliation(s)
- Aaron D Mickle
- Department of Pharmacology, The University of Iowa Roy J. and Lucile A. Carver College of Medicine, Iowa City, Iowa, USA; Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Andrew J Shepherd
- Department of Pharmacology, The University of Iowa Roy J. and Lucile A. Carver College of Medicine, Iowa City, Iowa, USA; Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Durga P Mohapatra
- Department of Pharmacology, The University of Iowa Roy J. and Lucile A. Carver College of Medicine, Iowa City, Iowa, USA; Department of Anesthesia, The University of Iowa Roy J. and Lucile A. Carver College of Medicine, Iowa City, Iowa, USA; Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri, USA.
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64
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Sousa-Valente J, Andreou AP, Urban L, Nagy I. Transient receptor potential ion channels in primary sensory neurons as targets for novel analgesics. Br J Pharmacol 2014; 171:2508-27. [PMID: 24283624 DOI: 10.1111/bph.12532] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 11/11/2013] [Accepted: 11/20/2013] [Indexed: 12/12/2022] Open
Abstract
The last decade has witnessed an explosion in novel findings relating to the molecules involved in mediating the sensation of pain in humans. Transient receptor potential (TRP) ion channels emerged as the greatest group of molecules involved in the transduction of various physical stimuli into neuronal signals in primary sensory neurons, as well as, in the development of pain. Here, we review the role of TRP ion channels in primary sensory neurons in the development of pain associated with peripheral pathologies and possible strategies to translate preclinical data into the development of effective new analgesics. Based on available evidence, we argue that nociception-related TRP channels on primary sensory neurons provide highly valuable targets for the development of novel analgesics and that, in order to reduce possible undesirable side effects, novel analgesics should prevent the translocation from the cytoplasm to the cell membrane and the sensitization of the channels rather than blocking the channel pore or binding sites for exogenous or endogenous activators.
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Affiliation(s)
- J Sousa-Valente
- Anaesthetics, Pain Medicine and Intensive Care Section, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, Chelsea and Westminster Hospital, London, UK
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65
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Janero DR, Makriyannis A. Terpenes and lipids of the endocannabinoid and transient-receptor-potential-channel biosignaling systems. ACS Chem Neurosci 2014; 5:1097-106. [PMID: 24866555 DOI: 10.1021/cn5000875] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Endocananbnoid-system G-protein coupled receptors (GPCRs) and transient receptor potential (TRP) cation channels are critical components of cellular biosignaling networks. These plasma-membrane proteins are pleiotropic in their ability to interact with and engage structurally diverse ligands. The endocannabinoid and TRP signaling systems overlap in their recognition properties with respect to select naturally occurring plant-derived ligands that belong to the terpene and lipid chemical classes, the overlap establishing a physiological connectivity between these two ubiquitous cell-signaling systems. Identification and pharmacological profiling of phytochemicals engaged by cannabinoid GPCRs and/or TRP channels has inspired the synthesis of novel designer ligands that interact with cannabinoid receptors and/or TRP channels as xenobiotics. Functional interplay between the endocannabinoid and TRP-channel signaling systems is responsible for the antinocifensive action of some synthetic cananbinoids (WIN55,212-2 and AM1241), vasorelaxation by the endocannabinoid N-arachidonylethanolamide (anandamide), and the pain-relief afforded by the synthetic anandamide analogue N-arachidonoylaminophenol (AM404), the active metabolite of the widely used nonprescription analgesic and antipyretic acetaminophen (paracetamol). The biological actions of some plant-derived cannabinoid-receptor (e.g., Δ(9)-tetrahydrocannabinol) or TRP-channel (e.g,, menthol) ligands either carry abuse potential themselves or promote the use of other addictive substances, suggesting the therapeutic potential for modulating these signaling systems for abuse-related disorders. The pleiotropic nature of and therapeutically relevant interactions between cananbinergic and TRP-channel signaling suggest the possibility of dual-acting ligands as drugs.
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Affiliation(s)
- David R. Janero
- Center for Drug Discovery and Departments of Chemistry
and Chemical Biology and Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts 02115-5000, United States
| | - Alexandros Makriyannis
- Center for Drug Discovery and Departments of Chemistry
and Chemical Biology and Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts 02115-5000, United States
- King Abdulaziz University, Jeddah, 22254, Saudi Arabia
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66
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Dussor G, Yan J, Xie JY, Ossipov MH, Dodick DW, Porreca F. Targeting TRP channels for novel migraine therapeutics. ACS Chem Neurosci 2014; 5:1085-96. [PMID: 25138211 PMCID: PMC4240253 DOI: 10.1021/cn500083e] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
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Migraine is increasingly understood
to be a disorder of the brain.
In susceptible individuals, a variety of “triggers”
may influence altered central excitability, resulting in the activation
and sensitization of trigeminal nociceptive afferents surrounding
blood vessels (i.e., the trigeminovascular system), leading to migraine
pain. Transient receptor potential (TRP) channels are expressed in
a subset of dural afferents, including those containing calcitonin
gene related peptide (CGRP). Activation of TRP channels promotes excitation
of nociceptive afferent fibers and potentially lead to pain. In addition
to pain, allodynia to mechanical and cold stimuli can result from
sensitization of both peripheral afferents and of central pain pathways.
TRP channels respond to a variety of endogenous conditions including
chemical mediators and low pH. These channels can be activated by
exogenous stimuli including a wide range of chemical and environmental
irritants, some of which have been demonstrated to trigger migraine
in humans. Activation of TRP channels can elicit CGRP release, and
blocking the effects of CGRP through receptor antagonism or antibody
strategies has been demonstrated to be effective in the treatment
of migraine. Identification of approaches that can prevent activation
of TRP channels provides an additional novel strategy for discovery
of migraine therapeutics.
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Affiliation(s)
- Gregory Dussor
- School
of Behavioral and Brain Sciences, University of Texas at Dallas, Dallas, Texas 75080, United States
| | - J. Yan
- Department
of Pharmacology, University of Washington, Seattle, Washington 98195, United States
| | - Jennifer Y. Xie
- Department
of Pharmacology, University of Arizona College of Medicine, Tucson, Arizona 85724, United States
| | - Michael H. Ossipov
- Department
of Pharmacology, University of Arizona College of Medicine, Tucson, Arizona 85724, United States
| | - David W. Dodick
- Department
of Neurology, Mayo Clinic Arizona, Phoenix, Arizona 85054, United States
| | - Frank Porreca
- Department
of Pharmacology, University of Arizona College of Medicine, Tucson, Arizona 85724, United States
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67
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Yin S, Luo J, Qian A, Yu W, Hu H. LE135, a retinoid acid receptor antagonist, produces pain through direct activation of TRP channels. Br J Pharmacol 2014; 171:1510-20. [PMID: 24308840 DOI: 10.1111/bph.12543] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 11/17/2013] [Accepted: 11/26/2013] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND AND PURPOSE Retinoids, through their activation of retinoic acid receptors (RARs) and retinoid X receptors, regulate diverse cellular processes, and pharmacological intervention in their actions has been successful in the treatment of skin disorders and cancers. Despite the many beneficial effects, administration of retinoids causes irritating side effects with unknown mechanisms. Here, we demonstrate that LE135 [4-(7,8,9,10-tetrahydro-5,7,7,10,10-pentamethyl-5H-benzo[e]naphtho[2,3-b][1,4]diazepin-13-yl)benzoic acid], a selective antagonist of RARβ , is a potent activator of the capsaicin (TRPV1) and wasabi (TRPA1) receptors, two critical pain-initiating cation channels. EXPERIMENTAL APPROACH We performed to investigate the excitatory effects of LE135 on TRPV1 and TRPA1 channels expressed in HEK293T cells and in dorsal root ganglia neurons with calcium imaging and patch-clamp recordings. We also used site-directed mutagenesis of the channels to determine the structural basis of LE135-induced activation of TRPV1 and TRPA1 channels and behavioural testing to examine if pharmacological inhibition and genetic deletion of the channels affected LE135-evoked pain-related behaviours. KEY RESULTS LE135 activated both the capsaicin receptor (TRPV1) and the allyl isothiocyanate receptor (TRPA1) heterologously expressed in HEK293T cells and endogenously expressed by sensory nociceptors. Mutations disrupting the capsaicin-binding site attenuated LE135 activation of TRPV1 channels and a single mutation (K170R) eliminated TRPA1 activity evoked by LE135. Intraplantar injection of LE135 evoked pain-related behaviours. Both TRPV1 and TRPA1 channels were involved in LE135-elicited pain-related responses, as shown by pharmacological and genetic ablation studies. CONCLUSIONS AND IMPLICATIONS This blocker of retinoid acid signalling also exerted non-genomic effects through activating the pain-initiating TRPV1 and TRPA1 channels.
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Affiliation(s)
- Shijin Yin
- College of Pharmacy, South-Central University for Nationalities, Wuhan, China; Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, TX, USA
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68
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Kacik M, Oliván-Viguera A, Köhler R. Modulation of K(Ca)3.1 channels by eicosanoids, omega-3 fatty acids, and molecular determinants. PLoS One 2014; 9:e112081. [PMID: 25372486 PMCID: PMC4221270 DOI: 10.1371/journal.pone.0112081] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 10/12/2014] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Cytochrome P450- and ω-hydrolase products (epoxyeicosatrienoic acids (EETs), hydroxyeicosatetraeonic acid (20-HETE)), natural omega-3 fatty acids (ω3), and pentacyclic triterpenes have been proposed to contribute to a wide range of vaso-protective and anti-fibrotic/anti-cancer signaling pathways including the modulation of membrane ion channels. Here we studied the modulation of intermediate-conductance Ca(2+)/calmodulin-regulated K(+) channels (K(Ca)3.1) by EETs, 20-HETE, ω3, and pentacyclic triterpenes and the structural requirements of these fatty acids to exert channel blockade. METHODOLOGY/PRINCIPAL FINDINGS We studied modulation of cloned human hK(Ca)3.1 and the mutant hK(Ca)3.1(V275A) in HEK-293 cells, of rK(Ca)3.1 in aortic endothelial cells, and of mK(Ca)3.1 in 3T3-fibroblasts by inside-out and whole-cell patch-clamp experiments, respectively. In inside-out patches, Ca(2+)-activated hK(Ca)3.1 were inhibited by the ω3, DHA and α-LA, and the ω6, AA, in the lower µmolar range and with similar potencies. 5,6-EET, 8,9-EET, 5,6-DiHETE, and saturated arachidic acid, had no appreciable effects. In contrast, 14,15-EET, its stable derivative, 14,15-EEZE, and 20-HETE produced channel inhibition. 11,12-EET displayed less inhibitory activity. The K(Ca)3.1(V275A) mutant channel was insensitive to any of the blocking EETs. Non-blocking 5,6-EET antagonized the inhibition caused by AA and augmented cloned hK(Ca)3.1 and rK(Ca)3.1 whole-cell currents. Pentacyclic triterpenes did not modulate K(Ca)3.1 currents. CONCLUSIONS/SIGNIFICANCE Inhibition of K(Ca)3.1 by EETs (14,15-EET), 20-HETE, and ω3 critically depended on the presence of electron double bonds and hydrophobicity within the 10 carbons preceding the carboxyl-head of the molecules. From the physiological perspective, metabolism of AA to non-blocking 5,6,- and 8,9-EET may cause AA-de-blockade and contribute to cellular signal transduction processes influenced by these fatty acids.
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Affiliation(s)
- Michael Kacik
- Faculty of Medicine, Philipps-University Marburg & Medical Center I, Clemenshospital/University Hospital of University Münster, 48153 Münster, Germany
| | | | - Ralf Köhler
- Aragon Institute of Health Sciences I+CS/IIS, 50009 Zaragoza, Spain
- Fundación Agencia Aragonesa para la Investigación y Desarrollo (ARAID), 50018 Zaragoza, Spain
- * E-mail:
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69
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Veldhuis NA, Poole DP, Grace M, McIntyre P, Bunnett NW. The G Protein–Coupled Receptor–Transient Receptor Potential Channel Axis: Molecular Insights for Targeting Disorders of Sensation and Inflammation. Pharmacol Rev 2014; 67:36-73. [DOI: 10.1124/pr.114.009555] [Citation(s) in RCA: 114] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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70
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Fleming I. The Pharmacology of the Cytochrome P450 Epoxygenase/Soluble Epoxide Hydrolase Axis in the Vasculature and Cardiovascular Disease. Pharmacol Rev 2014; 66:1106-40. [DOI: 10.1124/pr.113.007781] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
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71
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Choi SI, Yoo S, Lim JY, Hwang SW. Are sensory TRP channels biological alarms for lipid peroxidation? Int J Mol Sci 2014; 15:16430-57. [PMID: 25233127 PMCID: PMC4200803 DOI: 10.3390/ijms150916430] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2014] [Revised: 08/15/2014] [Accepted: 08/28/2014] [Indexed: 12/16/2022] Open
Abstract
Oxidative stress induces numerous biological problems. Lipid oxidation and peroxidation appear to be important steps by which exposure to oxidative stress leads the body to a disease state. For its protection, the body has evolved to respond to and eliminate peroxidation products through the acquisition of binding proteins, reducing and conjugating enzymes, and excretion systems. During the past decade, researchers have identified a group of ion channel molecules that are activated by oxidized lipids: transient receptor potential (TRP) channels expressed in sensory neurons. These ion channels are fundamentally detectors and signal converters for body-damaging environments such as heat and cold temperatures, mechanical attacks, and potentially toxic substances. When messages initiated by TRP activation arrive at the brain, we perceive pain, which results in our preparing defensive responses. Excessive activation of the sensory neuronal TRP channels upon prolonged stimulations sometimes deteriorates the inflammatory state of damaged tissues by promoting neuropeptide release from expresser neurons. These same paradigms may also work for pathologic changes in the internal lipid environment upon exposure to oxidative stress. Here, we provide an overview of the role of TRP channels and oxidized lipid connections during abnormally increased oxidative signaling, and consider the sensory mechanism of TRP detection as an alert system.
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Affiliation(s)
- Seung-In Choi
- Department of Biomedical Sciences and Department of Physiology, Korea University College of Medicine, Seoul 136-705, Korea.
| | - Sungjae Yoo
- Department of Biomedical Sciences and Department of Physiology, Korea University College of Medicine, Seoul 136-705, Korea.
| | - Ji Yeon Lim
- Department of Biomedical Sciences and Department of Physiology, Korea University College of Medicine, Seoul 136-705, Korea.
| | - Sun Wook Hwang
- Department of Biomedical Sciences and Department of Physiology, Korea University College of Medicine, Seoul 136-705, Korea.
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72
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Falck JR, Koduru SR, Mohapatra S, Manne R, Atcha KR, Atcha R, Manthati VL, Capdevila JH, Christian S, Imig JD, Campbell WB. 14,15-Epoxyeicosa-5,8,11-trienoic Acid (14,15-EET) surrogates: carboxylate modifications. J Med Chem 2014; 57:6965-72. [PMID: 25119815 PMCID: PMC4148164 DOI: 10.1021/jm500262m] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
![]()
The cytochrome P450 eicosanoid 14,15-epoxyeicosa-5,8,11-trienoic
acid (14,15-EET) is a powerful endogenous autacoid that has been ascribed
an impressive array of physiologic functions including regulation
of blood pressure. Because 14,15-EET is chemically and metabolically
labile, structurally related surrogates containing epoxide bioisosteres
were introduced and have become useful in vitro pharmacologic tools
but are not suitable for in vivo applications. A new generation of
EET mimics incorporating modifications to the carboxylate were prepared
and evaluated for vasorelaxation and inhibition of soluble epoxide
hydrolase (sEH). Tetrazole 19 (ED50 0.18 μM)
and oxadiazole-5-thione 25 (ED50 0.36 μM)
were 12- and 6-fold more potent, respectively, than 14,15-EET as vasorelaxants;
on the other hand, their ability to block sEH differed substantially,
i.e., 11 vs >500 nM. These data will expedite the development of
potent
and specific in vivo drug candidates.
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Affiliation(s)
- John R Falck
- Departments of Biochemistry and Pharmacology, University of Texas Southwestern Medical Center , 5323 Harry Hines Boulevard, Dallas, Texas 75390, United States
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73
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Kallenborn-Gerhardt W, Hohmann SW, Syhr KMJ, Schröder K, Sisignano M, Weigert A, Lorenz JE, Lu R, Brüne B, Brandes RP, Geisslinger G, Schmidtko A. Nox2-dependent signaling between macrophages and sensory neurons contributes to neuropathic pain hypersensitivity. Pain 2014; 155:2161-70. [PMID: 25139590 DOI: 10.1016/j.pain.2014.08.013] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 07/18/2014] [Accepted: 08/12/2014] [Indexed: 12/22/2022]
Abstract
Emerging lines of evidence indicate that production of reactive oxygen species (ROS) at distinct sites of the nociceptive system contributes to the processing of neuropathic pain. However, the mechanisms underlying ROS production during neuropathic pain processing are not fully understood. We here detected the ROS-generating nicotinamide adenine dinucleotide phosphate oxidase isoform Nox2 in macrophages of dorsal root ganglia (DRG) in mice. In response to peripheral nerve injury, Nox2-positive macrophages were recruited to DRG, and ROS production was increased in a Nox2-dependent manner. Nox2-deficient mice displayed reduced neuropathic pain behavior after peripheral nerve injury, whereas their immediate responses to noxious stimuli were normal. Moreover, injury-induced upregulation of tumor necrosis factor α was absent, and activating transcription factor 3 induction was reduced in DRG of Nox2-deficient mice, suggesting an attenuated macrophage-neuron signaling. These data suggest that Nox2-dependent ROS production in macrophages recruited to DRG contributes to neuropathic pain hypersensitivity, underlining the observation that Nox-derived ROS exert specific functions during the processing of pain.
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Affiliation(s)
- Wiebke Kallenborn-Gerhardt
- Pharmazentrum Frankfurt/ZAFES, Institute of Clinical Pharmacology, Goethe University Medical School, Frankfurt am Main, Germany
| | - Stephan W Hohmann
- Pharmazentrum Frankfurt/ZAFES, Institute of Clinical Pharmacology, Goethe University Medical School, Frankfurt am Main, Germany
| | - Katharina M J Syhr
- Pharmazentrum Frankfurt/ZAFES, Institute of Clinical Pharmacology, Goethe University Medical School, Frankfurt am Main, Germany
| | - Katrin Schröder
- Institute of Cardiovascular Physiology, Goethe University Medical School, Frankfurt am Main, Germany
| | - Marco Sisignano
- Pharmazentrum Frankfurt/ZAFES, Institute of Clinical Pharmacology, Goethe University Medical School, Frankfurt am Main, Germany
| | - Andreas Weigert
- Institute of Biochemistry I/ZAFES, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Jana E Lorenz
- Pharmazentrum Frankfurt/ZAFES, Institute of Clinical Pharmacology, Goethe University Medical School, Frankfurt am Main, Germany
| | - Ruirui Lu
- Pharmazentrum Frankfurt/ZAFES, Institute of Clinical Pharmacology, Goethe University Medical School, Frankfurt am Main, Germany; Institute of Pharmacology and Toxicology, ZBAF, Witten/Herdecke University, Witten, Germany
| | - Bernhard Brüne
- Institute of Biochemistry I/ZAFES, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Ralf P Brandes
- Institute of Cardiovascular Physiology, Goethe University Medical School, Frankfurt am Main, Germany
| | - Gerd Geisslinger
- Pharmazentrum Frankfurt/ZAFES, Institute of Clinical Pharmacology, Goethe University Medical School, Frankfurt am Main, Germany; Fraunhofer Institute for Molecular Biology and Applied Ecology - Project Group Translational Medicine and Pharmacology (IME-TMP), Frankfurt am Main, Germany
| | - Achim Schmidtko
- Pharmazentrum Frankfurt/ZAFES, Institute of Clinical Pharmacology, Goethe University Medical School, Frankfurt am Main, Germany; Institute of Pharmacology and Toxicology, ZBAF, Witten/Herdecke University, Witten, Germany.
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74
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TRP Channels Involved in Spontaneous L-Glutamate Release Enhancement in the Adult Rat Spinal Substantia Gelatinosa. Cells 2014; 3:331-62. [PMID: 24785347 PMCID: PMC4092856 DOI: 10.3390/cells3020331] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 04/10/2014] [Accepted: 04/18/2014] [Indexed: 12/31/2022] Open
Abstract
The spinal substantia gelatinosa (SG) plays a pivotal role in modulating nociceptive transmission through dorsal root ganglion (DRG) neurons from the periphery. TRP channels such as TRPV1 and TRPA1 channels expressed in the SG are involved in the regulation of the nociceptive transmission. On the other hand, the TRP channels located in the peripheral terminals of the DRG neurons are activated by nociceptive stimuli given to the periphery and also by plant-derived chemicals, which generates a membrane depolarization. The chemicals also activate the TRP channels in the SG. In this review, we introduce how synaptic transmissions in the SG neurons are affected by various plant-derived chemicals and suggest that the peripheral and central TRP channels may differ in property from each other.
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75
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Yoo S, Lim JY, Hwang SW. Sensory TRP channel interactions with endogenous lipids and their biological outcomes. Molecules 2014; 19:4708-44. [PMID: 24739932 PMCID: PMC6271031 DOI: 10.3390/molecules19044708] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 04/08/2014] [Accepted: 04/08/2014] [Indexed: 01/30/2023] Open
Abstract
Lipids have long been studied as constituents of the cellular architecture and energy stores in the body. Evidence is now rapidly growing that particular lipid species are also important for molecular and cellular signaling. Here we review the current information on interactions between lipids and transient receptor potential (TRP) ion channels in nociceptive sensory afferents that mediate pain signaling. Sensory neuronal TRP channels play a crucial role in the detection of a variety of external and internal changes, particularly with damaging or pain-eliciting potentials that include noxiously high or low temperatures, stretching, and harmful substances. In addition, recent findings suggest that TRPs also contribute to altering synaptic plasticity that deteriorates chronic pain states. In both of these processes, specific lipids are often generated and have been found to strongly modulate TRP activities, resulting primarily in pain exacerbation. This review summarizes three standpoints viewing those lipid functions for TRP modulations as second messengers, intercellular transmitters, or bilayer building blocks. Based on these hypotheses, we discuss perspectives that account for how the TRP-lipid interaction contributes to the peripheral pain mechanism. Still a number of blurred aspects remain to be examined, which will be answered by future efforts and may help to better control pain states.
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Affiliation(s)
- Sungjae Yoo
- Department of Biomedical Sciences, Korea University College of Medicine, Seoul 136-705, Korea.
| | - Ji Yeon Lim
- Department of Biomedical Sciences, Korea University College of Medicine, Seoul 136-705, Korea.
| | - Sun Wook Hwang
- Department of Biomedical Sciences, Korea University College of Medicine, Seoul 136-705, Korea.
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76
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Gallic acid functions as a TRPA1 antagonist with relevant antinociceptive and antiedematogenic effects in mice. Naunyn Schmiedebergs Arch Pharmacol 2014; 387:679-89. [PMID: 24722818 DOI: 10.1007/s00210-014-0978-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2013] [Accepted: 03/30/2014] [Indexed: 12/17/2022]
Abstract
The transient receptor potential ankyrin 1 (TRPA1) has been identified as a relevant target for the development of novel analgesics. Gallic acid (GA) is a polyphenolic compound commonly found in green tea and various berries and possesses a wide range of biological activities. The goal of this study was to identify GA as a TRPA1 antagonist and observe its antinociceptive effects in different pain models. First, we evaluated the ability of GA to affect cinnamaldehyde-induced calcium influx. Then, we observed the antinociceptive and antiedematogenic effects of GA (3-100 mg/kg) oral administration after the intraplantar (i.pl.) injection of TRPA1 agonists (allyl isothiocyanate, cinnamaldehyde, or hydrogen peroxide-H2O2) in either an inflammatory pain model (carrageenan i.pl. injection) or a neuropathic pain model (chronic constriction injury) in male Swiss mice (25-35 g). GA reduced the calcium influx mediated by TRPA1 activation. Moreover, the oral administration of GA decreased the spontaneous nociception triggered by allyl isothiocyanate, cinnamaldehyde, and H2O2. Carrageenan-induced allodynia and edema were largely reduced by the pretreatment with GA. Moreover, the administration of GA was also capable of decreasing cold and mechanical allodynia in a neuropathic pain model. Finally, GA was absorbed after oral administration and did not produce any detectable side effects. In conclusion, we found that GA is a TRPA1 antagonist with antinociceptive properties in relevant models of clinical pain without detectable side effects, which makes it a good candidate for the treatment of painful conditions.
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77
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Redmond WJ, Gu L, Camo M, McIntyre P, Connor M. Ligand determinants of fatty acid activation of the pronociceptive ion channel TRPA1. PeerJ 2014; 2:e248. [PMID: 24516781 PMCID: PMC3913255 DOI: 10.7717/peerj.248] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Accepted: 12/31/2013] [Indexed: 02/02/2023] Open
Abstract
Background and purpose. Arachidonic acid (AA) and its derivatives are important modulators of cellular signalling. The transient receptor potential cation channel subfamily A, member 1 (TRPA1) is a cation channel with important functions in mediating cellular responses to noxious stimuli and inflammation. There is limited information about the interactions between AA itself and TRPA1, so we investigated the effects of AA and key ethanolamide and amino acid/neurotransmitter derivatives of AA on hTRPA1. Experimental approach. HEK 293 cells expressing hTRPA1 were studied by measuring changes in intracellular calcium ([Ca]i) with a fluorescent dye and by standard whole cell patch clamp recordings. Key results. AA (30 μM) increased fluorescence in hTRPA1 expressing cells by 370% (notional EC50 13 μM). The covalent TRPA1 agonist cinnamaldehyde (300 μM) increased fluorescence by 430% (EC50, 11 μM). Anandamide (230%) and N-arachidonoyl tyrosine (170%) substantially activated hTRPA1 at 30 μM, however, N-arachidonoyl conjugates of glycine and taurine were less effective while N-acyl conjugates of 5-HT did not affect hTRPA1. Changing the acyl chain length or the number and position of double bonds reduced fatty acid efficacy at hTRPA1. Mutant hTRPA1 (Cys621, Cys641 and Cys665 changed to Ser) could be activated by AA (100 μM, 40% of wild type) but not by cinnamaldehyde (300 μM). Conclusions and implications. AA is a more potent activator of TRPA1 than its ethanolamide or amino acid/neurotransmitter derivatives and acts via a mechanism distinct from that of cinnamaldehyde, further underscoring the likelyhood of multiple pharmacologically exploitable sites on hTRPA1.
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Affiliation(s)
| | - Liuqiong Gu
- Department of Pharmacology, University of Melbourne , Parkville , Victoria , Australia
| | - Maxime Camo
- Australian School of Advanced Medicine, Macquarie University , NSW , Australia
| | - Peter McIntyre
- Department of Pharmacology, University of Melbourne , Parkville , Victoria , Australia ; Health Innovations Research Institute and School of Medical Sciences, RMIT University , Melbourne , Victoria , Australia
| | - Mark Connor
- Australian School of Advanced Medicine, Macquarie University , NSW , Australia
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Abstract
The transient receptor potential ankyrin subtype 1 protein (TRPA1) is a nonselective cation channel permeable to Ca(2+), Na(+), and K(+). TRPA1 is a promiscuous chemical nocisensor that is also involved in noxious cold and mechanical sensation. It is present in a subpopulation of Aδ- and C-fiber nociceptive sensory neurons as well as in other sensory cells including epithelial cells. In primary sensory neurons, Ca(2+) and Na(+) flowing through TRPA1 into the cell cause membrane depolarization, action potential discharge, and neurotransmitter release both at peripheral and central neural projections. In addition to being activated by cysteine and lysine reactive electrophiles and oxidants, TRPA1 is indirectly activated by pro-inflammatory agents via the phospholipase C signaling pathway, in which cytosolic Ca(2+) is an important regulator of channel gating. The finding that non-electrophilic compounds, including menthol and cannabinoids, activate TRPA1 may provide templates for the design of non-tissue damaging activators to fine-tune the activity of TRPA1 and raises the possibility that endogenous ligands sharing binding sites with such non-electrophiles exist and regulate TRPA1 channel activity. TRPA1 is promising as a drug target for novel treatments of pain, itch, and sensory hyperreactivity in visceral organs including the airways, bladder, and gastrointestinal tract.
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Affiliation(s)
- Peter M Zygmunt
- Clinical and Experimental Pharmacology, Clinical Chemistry, Department of Laboratory Medicine, Lund University, Skåne University Hospital, SE-221 85, Lund, Sweden,
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79
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Lu R, Lukowski R, Sausbier M, Zhang DD, Sisignano M, Schuh CD, Kuner R, Ruth P, Geisslinger G, Schmidtko A. BKCa channels expressed in sensory neurons modulate inflammatory pain in mice. Pain 2013; 155:556-565. [PMID: 24333777 DOI: 10.1016/j.pain.2013.12.005] [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] [Received: 06/04/2013] [Revised: 11/16/2013] [Accepted: 12/04/2013] [Indexed: 02/08/2023]
Abstract
Large conductance calcium-activated potassium (BKCa) channels are important regulators of neuronal excitability. Although there is electrophysiological evidence for BKCa channel expression in sensory neurons, their in vivo functions in pain processing have not been fully defined. Using a specific antibody, we demonstrate here that BKCa channels are expressed in subpopulations of peptidergic and nonpeptidergic nociceptors. To test a functional association of BKCa channel activity in sensory neurons with particular pain modalities, we generated mice in which BKCa channels are ablated specifically from sensory neurons and analyzed their behavior in various models of pain. Mutant mice showed increased nociceptive behavior in models of persistent inflammatory pain. However, their behavior in models of neuropathic or acute nociceptive pain was normal. Moreover, systemic administration of the BKCa channel opener, NS1619, inhibited persistent inflammatory pain. Our investigations provide in vivo evidence that BKCa channels expressed in sensory neurons exert inhibitory control on sensory input in inflammatory pain states.
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Affiliation(s)
- Ruirui Lu
- Pharmazentrum Frankfurt/ZAFES, Institut für Klinische Pharmakologie, Klinikum der Johann Wolfgang Goethe-Universität, Frankfurt am Main, Germany Pharmakologie, Toxikologie und Klinische Pharmazie, Institut für Pharmazie, Tübingen, Germany Pharmakologisches Institut, Universität Heidelberg, Heidelberg, Germany
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80
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Synthesis of lipid mediators during UVB-induced inflammatory hyperalgesia in rats and mice. PLoS One 2013; 8:e81228. [PMID: 24349046 PMCID: PMC3857181 DOI: 10.1371/journal.pone.0081228] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 10/09/2013] [Indexed: 01/05/2023] Open
Abstract
Peripheral sensitization during inflammatory pain is mediated by a variety of endogenous proalgesic mediators including a number of oxidized lipids, some of which serve endogenous modulators of sensory TRP-channels. These lipids are eicosanoids of the arachidonic acid and linoleic acid pathway, as well as lysophophatidic acids (LPAs). However, their regulation pattern during inflammatory pain and their contribution to peripheral sensitization is still unclear. Here, we used the UVB-model for inflammatory pain to investigate alterations of lipid concentrations at the site of inflammation, the dorsal root ganglia (DRGs) as well as the spinal dorsal horn and quantified 21 lipid species from five different lipid families at the peak of inflammation 48 hours post irradiation. We found that known proinflammatory lipids as well as lipids with unknown roles in inflammatory pain to be strongly increased in the skin, whereas surprisingly little changes of lipid levels were seen in DRGs or the dorsal horn. Importantly, although there are profound differences between the number of cytochrome (CYP) genes between mice and rats, CYP-derived lipids were regulated similarly in both species. Since TRPV1 agonists such as LPA 18∶1, 9- and 13-HODE, 5- and 12-HETE were elevated in the skin, they may contribute to thermal hyperalgesia and mechanical allodynia during UVB-induced inflammatory pain. These results may explain why some studies show relatively weak analgesic effects of cyclooxygenase inhibitors in UVB-induced skin inflammation, as they do not inhibit synthesis of other proalgesic lipids such as LPA 18∶1, 9-and 13-HODE and HETEs.
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81
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Sisignano M, Bennett DLH, Geisslinger G, Scholich K. TRP-channels as key integrators of lipid pathways in nociceptive neurons. Prog Lipid Res 2013; 53:93-107. [PMID: 24287369 DOI: 10.1016/j.plipres.2013.11.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Revised: 11/12/2013] [Accepted: 11/14/2013] [Indexed: 12/22/2022]
Abstract
TRP-channels are the most prominent family of ligand-gated ion channels for pain perception. In sensory neurons, TRPV1-V4, TRPA1 and TRPM8 are expressed and are responsible for the conversion of external stimuli to painful sensations. Under pathophysiological conditions, excessive activity of TRP-channels leads to mechanical allodynia and thermal hyperalgesia. Among the endogenous TRP-channel sensitizers, activators and inhibitors, more than 50 arachidonic acid- and linoleic acid-metabolites from the COX-, LOX- and CYP-pathways, as well as lysophospholipids and isoprenoids can be found. As a consequence, these lipids represent the vast majority of endogenous TRP-channel modulators in sensory neurons. Although the precise mechanisms of TRP-channel modulation by most lipids are still unknown, it became clear that lipids can either bind directly to the target TRP-channel or modulate TRP-channels indirectly by activating G-protein coupled receptors. Thus, TRP-channels seem to be key sensors for lipids, integrating and interpreting incoming signals from the different metabolic lipid pathways. Here, we discuss the specific properties of the currently known endogenous lipid-derived TRP-channel modulators concerning their ability to activate or inhibit TRP-channels, the molecular mechanisms of lipid/TRP-channel interactions and specific TRP-regulatory characteristics of the individual lipid families.
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Affiliation(s)
- Marco Sisignano
- Institute of Clinical Pharmacology, Pharmazentrum Frankfurt/ZAFES, University Hospital of the Goethe-University, D-60590 Frankfurt am Main, Germany
| | - David L H Bennett
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DU, UK
| | - Gerd Geisslinger
- Institute of Clinical Pharmacology, Pharmazentrum Frankfurt/ZAFES, University Hospital of the Goethe-University, D-60590 Frankfurt am Main, Germany
| | - Klaus Scholich
- Institute of Clinical Pharmacology, Pharmazentrum Frankfurt/ZAFES, University Hospital of the Goethe-University, D-60590 Frankfurt am Main, Germany.
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Meirer K, Steinhilber D, Proschak E. Inhibitors of the Arachidonic Acid Cascade: Interfering with Multiple Pathways. Basic Clin Pharmacol Toxicol 2013; 114:83-91. [DOI: 10.1111/bcpt.12134] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 09/04/2013] [Indexed: 12/30/2022]
Affiliation(s)
- Karin Meirer
- Institute of Pharmaceutical Chemistry; OSF/ZAFES/TMP; Goethe-University of Frankfurt; Frankfurt Germany
| | - Dieter Steinhilber
- Institute of Pharmaceutical Chemistry; OSF/ZAFES/TMP; Goethe-University of Frankfurt; Frankfurt Germany
| | - Ewgenij Proschak
- Institute of Pharmaceutical Chemistry; OSF/ZAFES/TMP; Goethe-University of Frankfurt; Frankfurt Germany
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83
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Koivisto A, Chapman H, Jalava N, Korjamo T, Saarnilehto M, Lindstedt K, Pertovaara A. TRPA1: a transducer and amplifier of pain and inflammation. Basic Clin Pharmacol Toxicol 2013; 114:50-5. [PMID: 24102997 DOI: 10.1111/bcpt.12138] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 09/10/2013] [Indexed: 12/01/2022]
Abstract
The transient receptor potential ankyrin 1 (TRPA1) ion channel on peripheral terminals of nociceptive primary afferent nerve fibres contributes to the transduction of noxious stimuli to electrical signals, while on central endings in the spinal dorsal horn, it amplifies transmission to spinal interneurons and projection neurons. The centrally propagating nociceptive signal that is induced and amplified by TRPA1 not only elicits pain sensation but also contributes to peripheral neurogenic inflammation through a peripheral axon reflex or a centrally mediated back propagating dorsal root reflex that releases vasoactive agents from sensory neurons in the periphery. Endogenous TRPA1 agonists that are generated under various pathophysiological conditions both in the periphery and in the spinal cord have TRPA1-mediated pro-nociceptive and pro-inflammatory effects. Among endogenous TRPA1 agonists that have been shown to play a role in the pathogenesis of pain and inflammatory conditions are, for example, methylglyoxal, 4-hydroxynonenal, 12-lipoxygenase-derived hepoxilin A3, 5,6-epoxyeicosatrienoic acid and reactive oxygen species, while mustard oil and cinnamaldehyde are most commonly used exogenous TRPA1 agonists in experimental studies. Among selective TRPA1 antagonists are HC-030031, A-967079, AP-14 and Chembridge-5861528. Recent evidence indicates that TRPA1 plays a role also in transition of acute to chronic pain. Due to its location on a subpopulation of pain-mediating primary afferent nerve fibres, blocking the TRPA1 channel is expected to have antinociceptive, antiallodynic and anti-inflammatory effects.
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84
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Alexander R, Kerby A, Aubdool AA, Power AR, Grover S, Gentry C, Grant AD. 4α-phorbol 12,13-didecanoate activates cultured mouse dorsal root ganglia neurons independently of TRPV4. Br J Pharmacol 2013; 168:761-72. [PMID: 22928864 DOI: 10.1111/j.1476-5381.2012.02186.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 07/22/2012] [Accepted: 08/15/2012] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE The Ca(2+) -permeable cation channel TRPV4 is activated by mechanical disturbance of the cell membrane and is implicated in mechanical hyperalgesia. Nerve growth factor (NGF) is increased during inflammation and causes mechanical hyperalgesia. 4α-phorbol 12,13-didecanoate (4αPDD) has been described as a selective TRPV4 agonist. We investigated NGF-induced hyperalgesia in TRPV4 wild-type (+/+) and knockout (-/-) mice, and the increases in [Ca(2+) ](i) produced by 4αPDD in cultured mouse dorsal root ganglia neurons following exposure to NGF. EXPERIMENTAL APPROACH Withdrawal thresholds to heat, von Frey hairs and pressure were measured in mice before and after systemic administration of NGF. Changes in intracellular Ca(2+) concentration were measured by ratiometric imaging with Fura-2 in cultured DRG and trigeminal ganglia (TG) neurons during perfusion of TRPV4 agonists. KEY RESULTS Administration of NGF caused a significant sensitization to heat and von Frey stimuli in TRPV4 +/+ and -/- mice, but only TRPV4 +/+ mice showed sensitization to noxious pressure. 4αPDD stimulated a dose-dependent increase in [Ca(2+) ](i) in neurons from +/+ and -/- mice, with the proportion of responding neurons and magnitude of increase unaffected by the genotype. In contrast, the selective TRPV4 agonist GSK1016790A failed to stimulate an increase in intracellular Ca(2+) in cultured neurons. Responses to 4αPDD were unaffected by pretreatment with NGF. CONCLUSIONS AND IMPLICATIONS TRPV4 contributes to mechanosensation in vivo, but there is little evidence for functional TRPV4 in cultured DRG and TG neurons. We conclude that 4αPDD activates these neurons independently of TRPV4, so it is not appropriate to refer to 4αPDD as a selective TRPV4 agonist.
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Affiliation(s)
- R Alexander
- Wolfson Centre for Age-Related Diseases, King's College London, London, UK
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85
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Endothelial control of vasodilation: integration of myoendothelial microdomain signalling and modulation by epoxyeicosatrienoic acids. Pflugers Arch 2013; 466:389-405. [PMID: 23748495 DOI: 10.1007/s00424-013-1303-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Revised: 05/24/2013] [Accepted: 05/26/2013] [Indexed: 12/17/2022]
Abstract
Endothelium-derived epoxyeicosatrienoic acids (EETs) are fatty acid epoxides that play an important role in the control of vascular tone in selected coronary, renal, carotid, cerebral and skeletal muscle arteries. Vasodilation due to endothelium-dependent smooth muscle hyperpolarization (EDH) has been suggested to involve EETs as a transferable endothelium-derived hyperpolarizing factor. However, this activity may also be due to EETs interacting with the components of other primary EDH-mediated vasodilator mechanisms. Indeed, the transfer of hyperpolarization initiated in the endothelium to the adjacent smooth muscle via gap junction connexins occurs separately or synergistically with the release of K(+) ions at discrete myoendothelial microdomain signalling sites. The net effects of such activity are smooth muscle hyperpolarization, closure of voltage-dependent Ca(2+) channels, phospholipase C deactivation and vasodilation. The spatially localized and key components of the microdomain signalling complex are the inositol 1,4,5-trisphosphate receptor-mediated endoplasmic reticulum Ca(2+) store, Ca(2+)-activated K(+) (KCa), transient receptor potential (TRP) and inward-rectifying K(+) channels, gap junctions and the smooth muscle Na(+)/K(+)-ATPase. Of these, TRP channels and connexins are key endothelial effector targets modulated by EETs. In an integrated manner, endogenous EETs enhance extracellular Ca(2+) influx (thereby amplifying and prolonging KCa-mediated endothelial hyperpolarization) and also facilitate the conduction of this hyperpolarization to spatially remote vessel regions. The contribution of EETs and the receptor and channel subtypes involved in EDH-related microdomain signalling, as a candidate for a universal EDH-mediated vasodilator mechanism, vary with vascular bed, species, development and disease and thus represent potentially selective targets for modulating specific artery function.
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86
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Reichling DB, Green PG, Levine JD. The fundamental unit of pain is the cell. Pain 2013; 154 Suppl 1:S2-9. [PMID: 23711480 DOI: 10.1016/j.pain.2013.05.037] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Revised: 04/12/2013] [Accepted: 05/20/2013] [Indexed: 12/22/2022]
Abstract
The molecular/genetic era has seen the discovery of a staggering number of molecules implicated in pain mechanisms [18,35,61,69,96,133,150,202,224]. This has stimulated pharmaceutical and biotechnology companies to invest billions of dollars to develop drugs that enhance or inhibit the function of many these molecules. Unfortunately this effort has provided a remarkably small return on this investment. Inevitably, transformative progress in this field will require a better understanding of the functional links among the ever-growing ranks of "pain molecules," as well as their links with an even larger number of molecules with which they interact. Importantly, all of these molecules exist side-by-side, within a functional unit, the cell, and its adjacent matrix of extracellular molecules. To paraphrase a recent editorial in Science magazine [223], although we live in the Golden age of Genetics, the fundamental unit of biology is still arguably the cell, and the cell is the critical structural and functional setting in which the function of pain-related molecules must be understood. This review summarizes our current understanding of the nociceptor as a cell-biological unit that responds to a variety of extracellular inputs with a complex and highly organized interaction of signaling molecules. We also discuss the insights that this approach is providing into peripheral mechanisms of chronic pain and sex dependence in pain.
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Affiliation(s)
- David B Reichling
- Department of Medicine, Division of Neuroscience, University of California-San Francisco, San Francisco, CA, USA; Department of Oral and Maxillofacial Surgery, Division of Neuroscience, University of California-San Francisco, San Francisco, CA, USA
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87
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Birnie M, Morrison R, Camara R, Strauss KI. Temporal changes of cytochrome P450 (Cyp) and eicosanoid-related gene expression in the rat brain after traumatic brain injury. BMC Genomics 2013; 14:303. [PMID: 23642095 PMCID: PMC3658912 DOI: 10.1186/1471-2164-14-303] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 04/16/2013] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Traumatic brain injury (TBI) induces arachidonic acid (ArA) release from cell membranes. ArA metabolites form a class of over 50 bioactive eicosanoids that can induce both adaptive and/or maladaptive brain responses. The dynamic metabolism of ArA to eicosanoids, and how they affect the injured brain, is poorly understood due to their diverse activities, trace levels, and short half-lives. The eicosanoids produced in the brain postinjury depend upon the enzymes present locally at any given time. Eicosanoids are synthesized by heme-containing enzymes, including cyclooxygenases, lipoxygenases, and arachidonate monoxygenases. The latter comprise a subset of the cytochrome P450 "Cyp" gene family that metabolize fatty acids, steroids, as well as endogenous and exogenous toxicants. However, for many of these genes neither baseline neuroanatomical nor injury-related temporal expression have been studied in the brain.In a rat model of parietal cortex TBI, Cyp and eicosanoid-related mRNA levels were determined at 6 h, 24 h, 3d, and 7d postinjury in parietal cortex and hippocampus, where dynamic changes in eicosanoids have been observed. Quantitative real-time polymerase chain reaction with low density arrays were used to assay 62 rat Cyps, 37 of which metabolize ArA or other unsaturated fatty acids; 16 eicosanoid-related enzymes that metabolize ArA or its metabolites; 8 eicosanoid receptors; 5 other inflammatory- and recovery-related genes, plus 2 mouse Cyps as negative controls and 3 highly expressed "housekeeping" genes. RESULTS Sixteen arachidonate monoxygenases, 17 eicosanoid-related genes, and 12 other Cyps were regulated in the brain postinjury (p < 0.05, Tukey HSD). Discrete tissue levels and distinct postinjury temporal patterns of gene expression were observed in hippocampus and parietal cortex. CONCLUSIONS The results suggest complex regulation of ArA and other lipid metabolism after TBI. Due to the temporal nature of brain injury-induced Cyp gene induction, manipulation of each gene (or its products) at a given time after TBI will be required to assess their contributions to secondary injury and/or recovery. Moreover, a better understanding of brain region localization and cell type-specific expression may be necessary to deduce the role of these eicosanoid-related genes in the healthy and injured brain.
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Affiliation(s)
- Matthew Birnie
- University of Cincinnati College of Medicine, 231 Albert Sabin Way ML 515, 45267 Cincinnati, OH, USA
| | - Ryan Morrison
- University of Cincinnati College of Medicine, 231 Albert Sabin Way ML 515, 45267 Cincinnati, OH, USA
| | - Ramatoulie Camara
- University of Cincinnati College of Medicine, 231 Albert Sabin Way ML 515, 45267 Cincinnati, OH, USA
| | - Kenneth I Strauss
- University of Cincinnati College of Medicine, 231 Albert Sabin Way ML 515, 45267 Cincinnati, OH, USA
- Present Address: Michigan State University College of Human Medicine, 333 Bostwick Ave NE, 49503 Grand Rapids, MI, USA
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88
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Wei H, Viisanen H, Amorim D, Koivisto A, Pertovaara A. Dissociated modulation of conditioned place-preference and mechanical hypersensitivity by a TRPA1 channel antagonist in peripheral neuropathy. Pharmacol Biochem Behav 2013; 104:90-6. [DOI: 10.1016/j.pbb.2012.12.014] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Revised: 12/11/2012] [Accepted: 12/19/2012] [Indexed: 12/22/2022]
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89
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Poole DP, Amadesi S, Veldhuis NA, Abogadie FC, Lieu T, Darby W, Liedtke W, Lew MJ, McIntyre P, Bunnett NW. Protease-activated receptor 2 (PAR2) protein and transient receptor potential vanilloid 4 (TRPV4) protein coupling is required for sustained inflammatory signaling. J Biol Chem 2013; 288:5790-802. [PMID: 23288842 DOI: 10.1074/jbc.m112.438184] [Citation(s) in RCA: 116] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
G protein-coupled receptors of nociceptive neurons can sensitize transient receptor potential (TRP) ion channels, which amplify neurogenic inflammation and pain. Protease-activated receptor 2 (PAR(2)), a receptor for inflammatory proteases, is a major mediator of neurogenic inflammation and pain. We investigated the signaling mechanisms by which PAR(2) regulates TRPV4 and determined the importance of tyrosine phosphorylation in this process. Human TRPV4 was expressed in HEK293 cells under control of a tetracycline-inducible promoter, allowing controlled and graded channel expression. In cells lacking TRPV4, the PAR(2) agonist stimulated a transient increase in [Ca(2+)](i). TRPV4 expression led to a markedly sustained increase in [Ca(2+)](i). Removal of extracellular Ca(2+) and treatment with the TRPV4 antagonists Ruthenium Red or HC067047 prevented the sustained response. Inhibitors of phospholipase A(2) and cytochrome P450 epoxygenase attenuated the sustained response, suggesting that PAR(2) generates arachidonic acid-derived lipid mediators, such as 5',6'-EET, that activate TRPV4. Src inhibitor 1 suppressed PAR(2)-induced activation of TRPV4, indicating the importance of tyrosine phosphorylation. The TRPV4 tyrosine mutants Y110F, Y805F, and Y110F/Y805F were expressed normally at the cell surface. However, PAR(2) was unable to activate TRPV4 with the Y110F mutation. TRPV4 antagonism suppressed PAR(2) signaling to primary nociceptive neurons, and TRPV4 deletion attenuated PAR(2)-stimulated neurogenic inflammation. Thus, PAR(2) activation generates a signal that induces sustained activation of TRPV4, which requires a key tyrosine residue (TRPV4-Tyr-110). This mechanism partly mediates the proinflammatory actions of PAR(2).
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Affiliation(s)
- Daniel P Poole
- Monash Institute of Pharmaceutical Sciences, Parkville, Victoria 3052, Australia
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90
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Ruparel S, Green D, Chen P, Hargreaves KM. The cytochrome P450 inhibitor, ketoconazole, inhibits oxidized linoleic acid metabolite-mediated peripheral inflammatory pain. Mol Pain 2012; 8:73. [PMID: 23006841 PMCID: PMC3488501 DOI: 10.1186/1744-8069-8-73] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Accepted: 09/20/2012] [Indexed: 01/26/2023] Open
Abstract
Background Oxidized linoleic acid metabolites (OLAMs) are a class of endogenous agonists to the transient receptor potential V1 (TRPV1) receptor. Although TRPV1 mediates inflammatory heat hyperalgesia, it is not known if the OLAMs contribute to the peripheral activation of this receptor during tissue inflammation. In the present study, we evaluated whether the OLAM system is activated during inflammation and whether cytochrome P450 enzymes mediate OLAM contributions to heat hyperalgesia using the complete Freund’s adjuvant (CFA) model of inflammation. Results Our results demonstrate that the intraplantar (ipl) injection of anti-OLAM antibodies significantly reversed CFA-induced heat hyperalgesia. Moreover, application of lipid extracts from inflamed rat skin to cultured sensory neurons triggered a significant release of iCGRP that is blocked by co-treatment with I-RTX, a TRPV1 antagonist. To determine the role of CYP enzymes in mediating OLAM effects, we used a broad spectrum CYP inhibitor, ketoconazole. Pretreatment with ketoconazole inhibited the release of TRPV1 agonists in lipid extracts from inflamed skin and significantly reversed CFA-induced heat hyperalgesia by a peripheral mechanism of action. Moreover, the ipl injection of linoleic acid to rats 24 hr after CFA evoked spontaneous nocifensive behaviors that were significantly reduced by capsazepine, by knockout of the TRPV1 gene, or by pretreatment with either anti-OLAM antibodies or ketoconazole. Conclusions Taken together, our data suggests that OLAMs contribute to inflammatory nociception in the periphery and that cytochrome P450 enzymes play a crucial role in mediating OLAM contributions to inflammatory heat hyperalgesia.
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Affiliation(s)
- Shivani Ruparel
- Department of Endodontics, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
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91
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The transient receptor potential channel TRPA1: from gene to pathophysiology. Pflugers Arch 2012; 464:425-58. [DOI: 10.1007/s00424-012-1158-z] [Citation(s) in RCA: 262] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Revised: 09/06/2012] [Accepted: 09/06/2012] [Indexed: 12/13/2022]
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92
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Lennertz RC, Kossyreva EA, Smith AK, Stucky CL. TRPA1 mediates mechanical sensitization in nociceptors during inflammation. PLoS One 2012; 7:e43597. [PMID: 22927999 PMCID: PMC3426543 DOI: 10.1371/journal.pone.0043597] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Accepted: 07/23/2012] [Indexed: 12/18/2022] Open
Abstract
Inflammation is a part of the body's natural response to tissue injury which initiates the healing process. Unfortunately, inflammation is frequently painful and leads to hypersensitivity to mechanical stimuli, which is difficult to treat clinically. While it is well established that altered sensory processing in the spinal cord contributes to mechanical hypersensitivity (central sensitization), it is still debated whether primary afferent neurons become sensitized to mechanical stimuli after tissue inflammation. We induced inflammation in C57BL/6 mice via intraplantar injection of Complete Freund's Adjuvant. Cutaneous C fibers exhibited increased action potential firing to suprathreshold mechanical stimuli. We found that abnormal responses to intense mechanical stimuli were completely suppressed by acute incubation of the receptive terminals with the TRPA1 inhibitor, HC-030031. Further, elevated responses were predominantly exhibited by a specific subgroup of C fibers, which we determined to be C-Mechano Cold sensitive fibers. Thus, in the presence of HC-030031, C fiber mechanical responses in inflamed mice were not different than responses in saline-injected controls. We also demonstrate that injection of the HC-030031 compound into the hind paw of inflamed mice alleviates behavioral mechanical hyperalgesia without affecting heat hyperalgesia. Further, we pharmacologically anesthetized the TRPA1-expressing fibers in vivo by co-injecting the membrane-impermeable sodium channel inhibitor QX-314 and the TRPA1 agonist cinnamaldehyde into the hind paw. This approach also alleviated behavioral mechanical hyperalgesia in inflamed mice but left heat hypersensitivity intact. Our findings indicate that C-Mechano Cold sensitive fibers exhibit enhanced firing to suprathreshold mechanical stimuli in a TRPA1-dependent manner during inflammation, and that input from these fibers drives mechanical hyperalgesia in inflamed mice.
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Affiliation(s)
- Richard C Lennertz
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
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93
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The Role of the Central Nervous System in Osteoarthritis Pain and Implications for Rehabilitation. Curr Rheumatol Rep 2012; 14:576-82. [DOI: 10.1007/s11926-012-0285-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Klafke JZ, da Silva MA, Trevisan G, Rossato MF, da Silva CR, Guerra GP, Villarinho JG, Rigo FK, Dalmolin GD, Gomez MV, Rubin MA, Ferreira J. Involvement of the glutamatergic system in the nociception induced intrathecally for a TRPA1 agonist in rats. Neuroscience 2012; 222:136-46. [PMID: 22820265 DOI: 10.1016/j.neuroscience.2012.07.022] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Revised: 07/10/2012] [Accepted: 07/11/2012] [Indexed: 02/08/2023]
Abstract
The transient receptor potential ankyrin 1 (TRPA1) is expressed in peripheral and spinal terminals of sensory neurons, jointly to the vanilloid receptor (TRPV1). A relevant peripheral role of TRPA1 receptor has been implicated in a variety of processes, including the detection of noxious cold, and diverse painful stimulus, but the functional role of TRPA1 receptor in nociceptive transmission at spinal cord in vivo is poorly known. Therefore, the aim of this study was to evaluate whether the glutamatergic system is involved in the transmission of nociceptive stimulus induced for a TRPA1 agonist in the rat spinal cord. We observed that cinnamaldehyde, a TRPA1 agonist, on spinal cord synaptosomes leads to an increase in [Ca(2+)](i) and a rapid release of glutamate, but was not able to change the specific [(3)H]-glutamate binding. In addition, spinally administered cinnamaldehyde produced heat hyperalgesia and mechanical allodynia in rats. This behavior was reduced by the co-injection (i.t.) of camphor (TRPA1 antagonist) or MK-801 (N-methyl-D-aspartate (NMDA) receptor antagonist) to cinnamaldehyde. Besides, the pretreatment with resiniferatoxin (RTX), a potent TRPV1 agonist, abolished the cinnamaldehyde-induced heat hyperalgesia. Here, we showed that intrathecal RTX results in a decrease in TRPA1 and TRPV1 immunoreactivity in dorsal root ganglion. Collectively, our results demonstrate the pertinent participation of spinal TRPA1 in the possible enhancement of glutamatergic transmission of nociceptive signals leading to increase of the hypersensitivity, here observed as heat hyperalgesia. Then the modulation of spinal TRPA1 might be a valuable target in painful conditions associated with central pain hypersensitivity.
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Affiliation(s)
- J Z Klafke
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS, Brazil.
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