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Cooper AH, Hedden NS, Corder G, Lamerand SR, Donahue RR, Morales-Medina JC, Selan L, Prasoon P, Taylor BK. Endogenous µ-opioid receptor activity in the lateral and capsular subdivisions of the right central nucleus of the amygdala prevents chronic postoperative pain. J Neurosci Res 2022; 100:48-65. [PMID: 33957003 PMCID: PMC8571119 DOI: 10.1002/jnr.24846] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 03/29/2021] [Indexed: 01/03/2023]
Abstract
Tissue injury induces a long-lasting latent sensitization (LS) of spinal nociceptive signaling that is kept in remission by an opposing µ-opioid receptor (MOR) constitutive activity. To test the hypothesis that supraspinal sites become engaged, we induced hindpaw inflammation, waited 3 weeks for mechanical hypersensitivity to resolve, and then injected the opioid receptor inhibitors naltrexone, CTOP or β-funaltrexamine subcutaneously, and/or into the cerebral ventricles. Intracerebroventricular injection of each inhibitor reinstated hypersensitivity and produced somatic signs of withdrawal, indicative of LS and endogenous opioid dependence, respectively. In naïve or sham controls, systemic naloxone (3 mg/kg) produced conditioned place aversion, and systemic naltrexone (3 mg/kg) increased Fos expression in the central nucleus of the amygdala (CeA). In LS animals tested 3 weeks after plantar incision, systemic naltrexone reinstated mechanical hypersensitivity and produced an even greater increase in Fos than in sham controls, particularly in the capsular subdivision of the right CeA. One third of Fos+ profiles co-expressed protein kinase C delta (PKCδ), and 35% of PKCδ neurons co-expressed tdTomato+ in Oprm1Cre ::tdTomato transgenic mice. CeA microinjection of naltrexone (1 µg) reinstated mechanical hypersensitivity only in male mice and did not produce signs of somatic withdrawal. Intra-CeA injection of the MOR-selective inhibitor CTAP (300 ng) reinstated hypersensitivity in both male and female mice. We conclude that MORs in the capsular subdivision of the right CeA prevent the transition from acute to chronic postoperative pain.
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Affiliation(s)
- Andrew H. Cooper
- Department of Anesthesiology and Perioperative Medicine, Pittsburgh Center for Pain Research, and the Pittsburgh Project to end Opioid Misuse, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Naomi S. Hedden
- Department of Anesthesiology and Perioperative Medicine, Pittsburgh Center for Pain Research, and the Pittsburgh Project to end Opioid Misuse, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Gregory Corder
- Department of Psychiatry and Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Sydney R. Lamerand
- Department of Anesthesiology and Perioperative Medicine, Pittsburgh Center for Pain Research, and the Pittsburgh Project to end Opioid Misuse, University of Pittsburgh, Pittsburgh, PA 15213, USA,Center for Neurosciences at the University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Renee R. Donahue
- Department of Physiology, University of Kentucky, Lexington, KY 40536, USA
| | | | - Lindsay Selan
- Department of Anesthesiology and Perioperative Medicine, Pittsburgh Center for Pain Research, and the Pittsburgh Project to end Opioid Misuse, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Pranav Prasoon
- Department of Anesthesiology and Perioperative Medicine, Pittsburgh Center for Pain Research, and the Pittsburgh Project to end Opioid Misuse, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Bradley K. Taylor
- Department of Anesthesiology and Perioperative Medicine, Pittsburgh Center for Pain Research, and the Pittsburgh Project to end Opioid Misuse, University of Pittsburgh, Pittsburgh, PA 15213, USA,Corresponding author: Bradley K. Taylor, 200 Lothrop Street, BSTW1455, Department of Anesthesiology & Perioperative Pain Medicine, University of Pittsburgh, Pittsburgh, PA, 15213, USA,
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2
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Griggs RB, Santos DF, Laird DE, Doolen S, Donahue RR, Wessel CR, Fu W, Sinha GP, Wang P, Zhou J, Brings S, Fleming T, Nawroth PP, Susuki K, Taylor BK. Methylglyoxal and a spinal TRPA1-AC1-Epac cascade facilitate pain in the db/db mouse model of type 2 diabetes. Neurobiol Dis 2019; 127:76-86. [PMID: 30807826 DOI: 10.1016/j.nbd.2019.02.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 02/21/2019] [Indexed: 12/21/2022] Open
Abstract
Painful diabetic neuropathy (PDN) is a devastating neurological complication of diabetes. Methylglyoxal (MG) is a reactive metabolite whose elevation in the plasma corresponds to PDN in patients and pain-like behavior in rodent models of type 1 and type 2 diabetes. Here, we addressed the MG-related spinal mechanisms of PDN in type 2 diabetes using db/db mice, an established model of type 2 diabetes, and intrathecal injection of MG in conventional C57BL/6J mice. Administration of either a MG scavenger (GERP10) or a vector overexpressing glyoxalase 1, the catabolic enzyme for MG, attenuated heat hypersensitivity in db/db mice. In C57BL/6J mice, intrathecal administration of MG produced signs of both evoked (heat and mechanical hypersensitivity) and affective (conditioned place avoidance) pain. MG-induced Ca2+ mobilization in lamina II dorsal horn neurons of C57BL/6J mice was exacerbated in db/db, suggestive of MG-evoked central sensitization. Pharmacological and/or genetic inhibition of transient receptor potential ankyrin subtype 1 (TRPA1), adenylyl cyclase type 1 (AC1), protein kinase A (PKA), or exchange protein directly activated by cyclic adenosine monophosphate (Epac) blocked MG-evoked hypersensitivity in C57BL/6J mice. Similarly, intrathecal administration of GERP10, or inhibitors of TRPA1 (HC030031), AC1 (NB001), or Epac (HJC-0197) attenuated hypersensitivity in db/db mice. We conclude that MG and sensitization of a spinal TRPA1-AC1-Epac signaling cascade facilitate PDN in db/db mice. Our results warrant clinical investigation of MG scavengers, glyoxalase inducers, and spinally-directed pharmacological inhibitors of a MG-TRPA1-AC1-Epac pathway for the treatment of PDN in type 2 diabetes.
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Affiliation(s)
- Ryan B Griggs
- Department of Physiology and Center for Analgesia Research Excellence, College of Medicine, University of Kentucky Medical Center, Lexington, KY, United States of America; Department of Neuroscience, Cell Biology, and Physiology, Boonshoft School of Medicine, Wright State University, Dayton, OH, United States of America.
| | - Diogo F Santos
- Department of Physiology and Center for Analgesia Research Excellence, College of Medicine, University of Kentucky Medical Center, Lexington, KY, United States of America
| | - Don E Laird
- Department of Physiology and Center for Analgesia Research Excellence, College of Medicine, University of Kentucky Medical Center, Lexington, KY, United States of America
| | - Suzanne Doolen
- Department of Physiology and Center for Analgesia Research Excellence, College of Medicine, University of Kentucky Medical Center, Lexington, KY, United States of America
| | - Renee R Donahue
- Department of Physiology and Center for Analgesia Research Excellence, College of Medicine, University of Kentucky Medical Center, Lexington, KY, United States of America
| | - Caitlin R Wessel
- Department of Physiology and Center for Analgesia Research Excellence, College of Medicine, University of Kentucky Medical Center, Lexington, KY, United States of America
| | - Weisi Fu
- Department of Physiology and Center for Analgesia Research Excellence, College of Medicine, University of Kentucky Medical Center, Lexington, KY, United States of America
| | - Ghanshyam P Sinha
- Department of Physiology and Center for Analgesia Research Excellence, College of Medicine, University of Kentucky Medical Center, Lexington, KY, United States of America
| | - Pingyuan Wang
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, United States of America
| | - Jia Zhou
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, United States of America
| | - Sebastian Brings
- Department of Nuclear Medicine, University Hospital of Heidelberg, INF 400 Heidelberg, Germany; Department of Medicine and Clinical Chemistry, University Hospital of Heidelberg, INF 410 Heidelberg, Germany
| | - Thomas Fleming
- Department of Medicine and Clinical Chemistry, University Hospital of Heidelberg, INF 410 Heidelberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Peter P Nawroth
- Department of Medicine and Clinical Chemistry, University Hospital of Heidelberg, INF 410 Heidelberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany; Joint Heidelberg-IDC Translational Diabetes Program, Helmholtz Zentrum München, Neuherberg, Germany
| | - Keiichiro Susuki
- Department of Neuroscience, Cell Biology, and Physiology, Boonshoft School of Medicine, Wright State University, Dayton, OH, United States of America
| | - Bradley K Taylor
- Department of Physiology and Center for Analgesia Research Excellence, College of Medicine, University of Kentucky Medical Center, Lexington, KY, United States of America; Department of Anesthesiology, University of Pittsburgh, Pittsburgh, PA, United States of America.
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3
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Taylor BK, Sinha GP, Donahue RR, Grachen CM, Morón JA, Doolen S. Opioid receptors inhibit the spinal AMPA receptor Ca 2+ permeability that mediates latent pain sensitization. Exp Neurol 2019; 314:58-66. [PMID: 30660616 DOI: 10.1016/j.expneurol.2019.01.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 12/24/2018] [Accepted: 01/05/2019] [Indexed: 01/02/2023]
Abstract
Acute inflammation induces sensitization of nociceptive neurons and triggers the accumulation of calcium permeable (CP) α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors (AMPARs) in the dorsal horn of the spinal cord. This coincides with behavioral signs of acute inflammatory pain, but whether CP-AMPARs contribute to chronic pain remains unclear. To evaluate this question, we first constructed current-voltage (IV) curves of C-fiber stimulus-evoked, AMPAR-mediated EPSCs in lamina II to test for inward rectification, a key characteristic of CP-AMPARs. We found that the intraplantar injection of complete Freund's adjuvant (CFA) induced an inward rectification at 3 d that persisted to 21 d after injury. Furthermore, the CP- AMPAR antagonist IEM-1460 (50 μM) inhibited AMPAR-evoked Ca2+ transients 21d after injury but had no effect in uninflamed mice. We then used a model of long-lasting vulnerability for chronic pain that is determined by the balance between latent central sensitization (LCS) and mu opioid receptor constitutive activity (MORCA). When administered 21 d after the intraplantar injection of CFA, intrathecal administration of the MORCA inverse agonist naltrexone (NTX, 1 μg, i.t.) reinstated mechanical hypersensitivity, and superfusion of spinal cord slices with NTX (10 μM) increased the peak amplitude of AMPAR-evoked Ca2+ transients in lamina II neurons. The CP-AMPAR antagonist naspm (0-10 nmol, i.t.) inhibited these NTX-induced increases in mechanical hypersensitivity. NTX had no effect in uninflamed mice. Subsequent western blot analysis of the postsynaptic density membrane fraction from lumbar dorsal horn revealed that CFA increased GluA1 expression at 2 d and GluA4 expression at both 2 and 21 d post-injury, indicating that not just the GluA1 subunit, but also the GluA4 subunit, contributes to the expression of CP-AMPARs and synaptic strength during hyperalgesia. GluA2 expression increased at 21 d, an unexpected result that requires further study. We conclude that after tissue injury, dorsal horn AMPARs retain a Ca2+ permeability that underlies LCS. Because of their effectiveness in reducing naltrexone-induced reinstatement of hyperalgesia and potentiation of AMPAR-evoked Ca2+ signals, CP-AMPAR inhibitors are a promising class of agents for the treatment of chronic inflammatory pain.
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Affiliation(s)
- Bradley K Taylor
- Department of Anesthesiology, Pittsburgh Center for Pain Research, University of Pittsburgh School of Medicine, 200 Lothrop St. Pittsburgh, PA 15213, USA; Department of Physiology, University of Kentucky School of Medicine, 800 Rose, St. Lexington, KY 40536-0298, USA.
| | - Ghanshyam P Sinha
- Department of Anesthesiology, Pittsburgh Center for Pain Research, University of Pittsburgh School of Medicine, 200 Lothrop St. Pittsburgh, PA 15213, USA; Department of Physiology, University of Kentucky School of Medicine, 800 Rose, St. Lexington, KY 40536-0298, USA.
| | - Renee R Donahue
- Department of Physiology, University of Kentucky School of Medicine, 800 Rose, St. Lexington, KY 40536-0298, USA.
| | - Carolyn M Grachen
- Department of Anesthesiology, Pittsburgh Center for Pain Research, University of Pittsburgh School of Medicine, 200 Lothrop St. Pittsburgh, PA 15213, USA; Department of Physiology, University of Kentucky School of Medicine, 800 Rose, St. Lexington, KY 40536-0298, USA.
| | - Jose A Morón
- Department of Anesthesiology, Washington University Pain Center, Washington University School of Medicine, 600 South Euclid, St Louis, MO 63110, USA.
| | - Suzanne Doolen
- Department of Anesthesiology, Pittsburgh Center for Pain Research, University of Pittsburgh School of Medicine, 200 Lothrop St. Pittsburgh, PA 15213, USA; Department of Physiology, University of Kentucky School of Medicine, 800 Rose, St. Lexington, KY 40536-0298, USA.
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4
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Mamet J, Klukinov M, Harris S, Manning DC, Xie S, Pascual C, Taylor BK, Donahue RR, Yeomans DC. Intrathecal administration of AYX2 DNA-decoy produces a long-term pain treatment in rat models of chronic pain by inhibiting the KLF6, KLF9 and KLF15 transcription factors. Mol Pain 2018; 13:1744806917727917. [PMID: 28814144 PMCID: PMC5582654 DOI: 10.1177/1744806917727917] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Background Nociception is maintained by genome-wide regulation of transcription in the dorsal root ganglia—spinal cord network. Hence, transcription factors constitute a promising class of targets for breakthrough pharmacological interventions to treat chronic pain. DNA decoys are oligonucleotides and specific inhibitors of transcription factor activities. A methodological series of in vivo–in vitro screening cycles was performed with decoy/transcription factor couples to identify targets capable of producing a robust and long-lasting inhibition of established chronic pain. Decoys were injected intrathecally and their efficacy was tested in the spared nerve injury and chronic constriction injury models of chronic pain in rats using repetitive von Frey testing. Results Results demonstrated that a one-time administration of decoys binding to the Kruppel-like transcription factors (KLFs) 6, 9, and 15 produces a significant and weeks–month long reduction in mechanical hypersensitivity compared to controls. In the spared nerve injury model, decoy efficacy was correlated to its capacity to bind KLF15 and KLF9 at a specific ratio, while in the chronic constriction injury model, efficacy was correlated to the combined binding capacity to KLF6 and KLF9. AYX2, an 18-bp DNA decoy binding KLF6, KLF9, and KLF15, was optimized for clinical development, and it demonstrated significant efficacy in these models. Conclusions These data highlight KLF6, KLF9, and KLF15 as transcription factors required for the maintenance of chronic pain and illustrate the potential therapeutic benefits of AYX2 for the treatment of chronic pain.
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Gollihue JL, Patel SP, Eldahan KC, Cox DH, Donahue RR, Taylor BK, Sullivan PG, Rabchevsky AG. Effects of Mitochondrial Transplantation on Bioenergetics, Cellular Incorporation, and Functional Recovery after Spinal Cord Injury. J Neurotrauma 2018; 35:1800-1818. [PMID: 29648982 DOI: 10.1089/neu.2017.5605] [Citation(s) in RCA: 106] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Our previous studies reported that pharmacological maintenance of mitochondrial bioenergetics after experimental spinal cord injury (SCI) provided functional neuroprotection. Recent evidence indicates that endogenous mitochondrial transfer is neuroprotective as well, and, therefore, we extended these studies with a novel approach to transplanting exogenous mitochondria into the injured rat spinal cord. Using a rat model of L1/L2 contusion SCI, we herein report that transplantation of exogenous mitochondria derived from either cell culture or syngeneic leg muscle maintained acute bioenergetics of the injured spinal cord in a concentration-dependent manner. Moreover, transplanting transgenically labeled turbo green fluorescent (tGFP) PC12-derived mitochondria allowed for visualization of their incorporation in both a time-dependent and cell-specific manner at 24 h, 48 h, and 7 days post-injection. tGFP mitochondria co-localized with multiple resident cell types, although they were absent in neurons. Despite their contribution to the maintenance of normal bioenergetics, mitochondrial transplantation did not yield long-term functional neuroprotection as assessed by overall tissue sparing or recovery of motor and sensory functions. These experiments are the first to investigate mitochondrial transplantation as a therapeutic approach to treating spinal cord injury. Our initial bioenergetic results are encouraging, and although they did not translate into improved long-term outcome measures, caveats and technical hurdles are discussed that can be addressed in future studies to potentially increase long-term efficacy of transplantation strategies.
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Affiliation(s)
- Jenna L Gollihue
- 1 Department of Physiology, University of Kentucky , Lexington, Kentucky.,2 Spinal Cord & Brain Injury Research Center, University of Kentucky , Lexington, Kentucky
| | - Samir P Patel
- 1 Department of Physiology, University of Kentucky , Lexington, Kentucky.,2 Spinal Cord & Brain Injury Research Center, University of Kentucky , Lexington, Kentucky
| | - Khalid C Eldahan
- 1 Department of Physiology, University of Kentucky , Lexington, Kentucky.,2 Spinal Cord & Brain Injury Research Center, University of Kentucky , Lexington, Kentucky
| | - David H Cox
- 2 Spinal Cord & Brain Injury Research Center, University of Kentucky , Lexington, Kentucky
| | - Renee R Donahue
- 1 Department of Physiology, University of Kentucky , Lexington, Kentucky
| | - Bradley K Taylor
- 1 Department of Physiology, University of Kentucky , Lexington, Kentucky.,2 Spinal Cord & Brain Injury Research Center, University of Kentucky , Lexington, Kentucky
| | - Patrick G Sullivan
- 2 Spinal Cord & Brain Injury Research Center, University of Kentucky , Lexington, Kentucky.,3 Department of Neuroscience, University of Kentucky , Lexington, Kentucky
| | - Alexander G Rabchevsky
- 1 Department of Physiology, University of Kentucky , Lexington, Kentucky.,2 Spinal Cord & Brain Injury Research Center, University of Kentucky , Lexington, Kentucky
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6
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Griggs RB, Laird DE, Donahue RR, Fu W, Taylor BK. Methylglyoxal Requires AC1 and TRPA1 to Produce Pain and Spinal Neuron Activation. Front Neurosci 2017; 11:679. [PMID: 29270106 PMCID: PMC5723675 DOI: 10.3389/fnins.2017.00679] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 11/21/2017] [Indexed: 12/04/2022] Open
Abstract
Methylglyoxal (MG) is a metabolite of glucose that may contribute to peripheral neuropathy and pain in diabetic patients. MG increases intracellular calcium in sensory neurons and produces behavioral nociception via the cation channel transient receptor potential ankyrin 1 (TRPA1). However, rigorous characterization of an animal model of methylglyoxal-evoked pain is needed, including testing whether methylglyoxal promotes negative pain affect. Furthermore, it remains unknown whether methylglyoxal is sufficient to activate neurons in the spinal cord dorsal horn, whether this requires TRPA1, and if the calcium-sensitive adenylyl cyclase 1 isoform (AC1) contributes to MG-evoked pain. We administered intraplantar methylglyoxal and then evaluated immunohistochemical phosphorylation of extracellular signal-regulated kinase (p-ERK) and multiple pain-like behaviors in wild-type rats and mice and after disruption of either TRPA1 or AC1. Methylglyoxal produced conditioned place avoidance (CPA) (a measure of affective pain), dose-dependent licking and lifting nociceptive behaviors, hyperalgesia to heat and mechanical stimulation, and p-ERK in the spinal cord dorsal horn. TRPA1 knockout or intrathecal administration of a TRPA1 antagonist (HC030031) attenuated methylglyoxal-evoked p-ERK, nociception, and hyperalgesia. AC1 knockout abolished hyperalgesia but not nociceptive behaviors. These results indicate that intraplantar administration of methylglyoxal recapitulates multiple signs of painful diabetic neuropathy found in animal models of or patients with diabetes, including the activation of spinal nociresponsive neurons and the potential involvement of a TRPA1-AC1 sensitization mechanism. We conclude that administration of MG is a valuable model for investigating both peripheral and central components of a MG-TRPA1-AC1 pathway that contribute to painful diabetic neuropathy.
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Affiliation(s)
- Ryan B Griggs
- Department of Physiology, University of Kentucky, College of Medicine, Lexington, KY, United States
| | - Don E Laird
- Department of Physiology, University of Kentucky, College of Medicine, Lexington, KY, United States
| | - Renee R Donahue
- Department of Physiology, University of Kentucky, College of Medicine, Lexington, KY, United States.,Center for Analgesia Research Excellence, University of Kentucky College of Medicine, Lexington, KY, United States
| | - Weisi Fu
- Department of Physiology, University of Kentucky, College of Medicine, Lexington, KY, United States
| | - Bradley K Taylor
- Department of Physiology, University of Kentucky, College of Medicine, Lexington, KY, United States.,Center for Analgesia Research Excellence, University of Kentucky College of Medicine, Lexington, KY, United States.,Spinal Cord and Brain Injury Research Center, College of Medicine, University of Kentucky, Lexington, KY, United States
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7
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Mamet J, Harris S, Klukinov M, Yeomans DC, Donahue RR, Taylor BK, Eddinger K, Yaksh T, Manning DC. Pharmacology, pharmacokinetics, and metabolism of the DNA-decoy AYX1 for the prevention of acute and chronic post-surgical pain. Mol Pain 2017; 13:1744806917703112. [PMID: 28394696 PMCID: PMC5407669 DOI: 10.1177/1744806917703112] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Background AYX1 is an unmodified DNA-decoy designed to reduce acute post-surgical pain and its chronification with a single intrathecal dose at the time of surgery. AYX1 inhibits the transcription factor early growth response protein 1, which is transiently induced at the time of injury and triggers gene regulation in the dorsal root ganglia and spinal cord that leads to long-term sensitization and pain. This work characterizes the AYX1 dose-response profile in rats and the link to AYX1 pharmacokinetics and metabolism in the cerebrospinal fluid, dorsal root ganglia, and spinal cord. Results The effects of ascending dose-levels of AYX1 on mechanical hypersensitivity were measured in the spared nerve injury model of chronic pain and in a plantar incision model of acute post-surgical pain. AYX1 dose-response profile shows that efficacy rapidly increases from a minimum effective dose of ∼ 0.5 mg to a peak maximum effective dose of ∼ 1 mg. With further dose escalation, the efficacy paradoxically appears to decrease by ∼ 30% and then returns to full efficacy at the maximum feasible dose of ∼ 4 mg. The reduction of efficacy is associated to doses triggering a near-saturation of AYX1 metabolism by nucleases in the cerebrospinal fluid and a paradoxical reduction of AYX1 exposure during the period of early growth response protein 1 induction. This effect is overcome at higher doses that compensate for the effect of metabolism. Discussion AYX1 is a competitive antagonist of early growth response protein 1, which is consistent with the overall increased efficacy observed as dose-levels initially escalate. Chemically, AYX1 is unprotected against degradation by nucleases. The sensitivity to nucleases is reflected in a paradoxical reduction of efficacy in the dose-response curve. Conclusions These findings point to the importance of the nuclease environment of the cerebrospinal fluid to the research and development of AYX1 and other intrathecal nucleotide-based therapeutics.
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Affiliation(s)
| | | | | | | | | | - Brad K Taylor
- 3 Department of Physiology, University of Kentucky, KY, USA
| | - Kelly Eddinger
- 4 Department of Anesthesiology and Pharmacology, University of California, San Diego, CA, USA
| | - Tony Yaksh
- 4 Department of Anesthesiology and Pharmacology, University of California, San Diego, CA, USA
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Harte SE, Meyers JB, Donahue RR, Taylor BK, Morrow TJ. Mechanical Conflict System: A Novel Operant Method for the Assessment of Nociceptive Behavior. PLoS One 2016; 11:e0150164. [PMID: 26915030 PMCID: PMC4767889 DOI: 10.1371/journal.pone.0150164] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 02/10/2016] [Indexed: 11/19/2022] Open
Abstract
A new operant test for preclinical pain research, termed the Mechanical Conflict System (MCS), is presented. Rats were given a choice either to remain in a brightly lit compartment or to escape to a dark compartment by crossing an array of height-adjustable nociceptive probes. Latency to escape the light compartment was evaluated with varying probe heights (0, .5, 1, 2, 3, and 4 mm above compartment floor) in rats with neuropathic pain induced by constriction nerve injury (CCI) and in naive control rats. Escape responses in CCI rats were assessed following intraperitoneal administration of pregabalin (10 and 30 mg/kg), morphine (2.5 and 5 mg/kg), and the tachykinin NK1 receptor antagonist, RP 67580 (1 and 10 mg/kg). Results indicate that escape latency increased as a function of probe height in both naive and CCI rats. Pregabalin (10 and 30 mg/kg) and morphine (5 mg/kg), but not RP 67580, decreased latency to escape in CCI rats suggesting an antinociceptive effect. In contrast, morphine (10 mg/kg) but not pregabalin (30 mg/kg) increased escape latency in naive rats suggesting a possible anxiolytic action of morphine in response to light-induced fear. No order effects following multiple test sessions were observed. We conclude that the MCS is a valid method to assess behavioral signs of affective pain in rodents.
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Affiliation(s)
- Steven E. Harte
- Department of Anesthesiology, Chronic Pain and Fatigue Research Center, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Internal Medicine, Division of Rheumatology, University of Michigan, Ann Arbor, Michigan, United States of America
- Neurology Service, Veterans Affairs Ann Arbor Healthcare System, Ann Arbor, Michigan, United States of America
- * E-mail:
| | - Jessica B. Meyers
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, United States of America
- Neurology Service, Veterans Affairs Ann Arbor Healthcare System, Ann Arbor, Michigan, United States of America
| | - Renee R. Donahue
- Department of Physiology, University of Kentucky, Lexington, Kentucky, United States of America
| | - Bradley K. Taylor
- Department of Physiology, University of Kentucky, Lexington, Kentucky, United States of America
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky, United States of America
| | - Thomas J. Morrow
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, United States of America
- Neurology Service, Veterans Affairs Ann Arbor Healthcare System, Ann Arbor, Michigan, United States of America
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9
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Pereira MP, Donahue RR, Dahl JB, Werner M, Taylor BK, Werner MU. Endogenous Opioid-Masked Latent Pain Sensitization: Studies from Mouse to Human. PLoS One 2015; 10:e0134441. [PMID: 26305798 PMCID: PMC4549112 DOI: 10.1371/journal.pone.0134441] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 06/08/2015] [Indexed: 01/20/2023] Open
Abstract
Following the resolution of a severe inflammatory injury in rodents, administration of mu-opioid receptor inverse agonists leads to reinstatement of pain hypersensitivity. The mechanisms underlying this form of latent pain sensitization (LS) likely contribute to the development of chronic pain, but LS has not yet been demonstrated in humans. Using a C57BL/6 mouse model of cutaneous mild heat injury (MHI) we demonstrated a dose-dependent reinstatement of pain sensitization, assessed as primary (P < 0.001) and secondary hyperalgesia (P < 0.001) by naloxone (0.3–10 mg/kg), 168 hrs after the induction of MHI. Forward-translating the dose data to a human MHI model (n = 12) we could show that LS does indeed occur after naloxone 2 mg/kg, 168 hrs after a MHI. Our previous unsuccessful efforts to demonstrate unmasking of LS in humans are thus likely explained by an insufficient naloxone dose (0.021 mg/kg). However, while LS was consistently demonstrated in 21/24 mice, LS was only seen in 4/12 subjects. This difference is likely due to selection bias since the C57BL/6 mouse strain exhibits markedly enhanced pain sensitivity in assays of acute thermal nociception. Future exploratory studies in humans should prioritize inclusion of “high-sensitizers” prone to develop LS and use post-surgical models to elucidate markers of vulnerability to chronic postsurgical pain.
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Affiliation(s)
- Manuel P. Pereira
- Department of Anaesthesia, Centre of Head and Orthopaedics, Rigshospitalet, Copenhagen, Denmark
| | - Renee R. Donahue
- Department of Physiology, University of Kentucky, Lexington, KY, United States of America
| | - Jørgen B. Dahl
- Department of Anaesthesia, Centre of Head and Orthopaedics, Rigshospitalet, Copenhagen, Denmark
| | - Marianne Werner
- Department of Cardiology, Rigshospitalet, Copenhagen, Denmark
| | - Bradley K. Taylor
- Multidisciplinary Pain Center, Neuroscience Center, Rigshospitalet, Copenhagen, Denmark
| | - Mads U. Werner
- Multidisciplinary Pain Center, Neuroscience Center, Rigshospitalet, Copenhagen, Denmark
- * E-mail:
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Rahn EJ, Iannitti T, Donahue RR, Taylor BK. Sex differences in a mouse model of multiple sclerosis: neuropathic pain behavior in females but not males and protection from neurological deficits during proestrus. Biol Sex Differ 2014; 5:4. [PMID: 24581045 PMCID: PMC3974112 DOI: 10.1186/2042-6410-5-4] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Accepted: 01/31/2014] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Multiple sclerosis (MS), a demyelinating disease of the central nervous system, is one of the most prevalent neurological disorders in the industrialized world. This disease afflicts more than two million people worldwide, over two thirds of which are women. MS is typically diagnosed between the ages of 20-40 and can produce debilitating neurological impairments including muscle spasticity, muscle paralysis, and chronic pain. Despite the large sex disparity in MS prevalence, clinical and basic research investigations of how sex and estrous cycle impact development, duration, and severity of neurological impairments and pain symptoms are limited. To help address these questions, we evaluated behavioral signs of sensory and motor functions in one of the most widely characterized animal models of MS, the experimental autoimmune encephalomyelitis (EAE) model. METHODS C57BL/6 male and female mice received flank injection of complete Freund's adjuvant (CFA) or CFA plus myelin oligodendrocyte glycoprotein 35-55 (MOG35-55) to induce EAE. Experiment 1 evaluated sex differences of EAE-induced neurological motor deficits and neuropathic pain-like behavior over 3 weeks, while experiment 2 evaluated the effect of estrous phase in female mice on the same behavioral measures for 3 months. EAE-induced neurological motor deficits including gait analysis and forelimb grip strength were assessed. Neuropathic pain-like behaviors evaluated included sensitivity to mechanical, cold, and heat stimulations. Estrous cycle was determined daily via vaginal lavage. RESULTS MOG35-55-induced EAE produced neurological impairments (i.e., motor dysfunction) including mild paralysis and decreases in grip strength in both females and males. MOG35-55 produced behavioral signs of neuropathic pain-mechanical and cold hypersensitivity-in females, but not males. MOG35-55 did not change cutaneous heat sensitivity in either sex. Administration of CFA or CFA + MOG35-55 prolonged the time spent in diestrus for 2 weeks, after which normal cycling returned. MOG35-55 produced fewer neurological motor deficits when mice were in proestrus relative to non-proestrus phases. CONCLUSIONS We conclude that female mice are superior to males for the study of neuropathic pain-like behaviors associated with MOG35-55-induced EAE. Further, proestrus may be protective against EAE-induced neurological deficits, thus necessitating further investigation into the impact that estrous cycle exerts on MS symptoms.
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Affiliation(s)
| | | | | | - Bradley K Taylor
- Department of Physiology, University of Kentucky, 800 Rose Street, Lexington, KY 40536, USA.
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Mamet J, Klukinov M, Yaksh TL, Malkmus SA, Williams S, Harris S, Manning DC, Taylor BK, Donahue RR, Porreca F, Xie JY, Oyarzo J, Brennan TJ, Subieta A, Schmidt WK, Yeomans DC. Single intrathecal administration of the transcription factor decoy AYX1 prevents acute and chronic pain after incisional, inflammatory, or neuropathic injury. Pain 2014; 155:322-333. [DOI: 10.1016/j.pain.2013.10.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Revised: 10/02/2013] [Accepted: 10/15/2013] [Indexed: 12/20/2022]
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Corder G, Doolen S, Donahue RR, Winter MK, Jutras BL, He Y, Hu X, Wieskopf JS, Mogil JS, Storm DR, Wang ZJ, McCarson KE, Taylor BK. Constitutive μ-opioid receptor activity leads to long-term endogenous analgesia and dependence. Science 2013; 341:1394-9. [PMID: 24052307 DOI: 10.1126/science.1239403] [Citation(s) in RCA: 168] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Opioid receptor antagonists increase hyperalgesia in humans and animals, which indicates that endogenous activation of opioid receptors provides relief from acute pain; however, the mechanisms of long-term opioid inhibition of pathological pain have remained elusive. We found that tissue injury produced μ-opioid receptor (MOR) constitutive activity (MOR(CA)) that repressed spinal nociceptive signaling for months. Pharmacological blockade during the posthyperalgesia state with MOR inverse agonists reinstated central pain sensitization and precipitated hallmarks of opioid withdrawal (including adenosine 3',5'-monophosphate overshoot and hyperalgesia) that required N-methyl-D-aspartate receptor activation of adenylyl cyclase type 1. Thus, MOR(CA) initiates both analgesic signaling and a compensatory opponent process that generates endogenous opioid dependence. Tonic MOR(CA) suppression of withdrawal hyperalgesia may prevent the transition from acute to chronic pain.
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Affiliation(s)
- G Corder
- Department of Physiology, University of Kentucky, Lexington, KY 40536, USA
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Morgenweck J, Griggs RB, Donahue RR, Zadina JE, Taylor BK. PPARγ activation blocks development and reduces established neuropathic pain in rats. Neuropharmacology 2013; 70:236-46. [PMID: 23415633 DOI: 10.1016/j.neuropharm.2013.01.020] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Revised: 12/18/2012] [Accepted: 01/16/2013] [Indexed: 12/30/2022]
Abstract
Peroxisome proliferator-activated receptor gamma (PPARγ) is emerging as a new pharmacotherapeutic target for chronic pain. When oral (3-30 mg/kg/day in chow for 7 wk) or twice-daily intraperitoneal (1-10 mg/kg/day for 2 wk) administration began before spared nerve injury (SNI), pioglitazone, a PPARγ agonist, dose-dependently prevented multiple behavioral signs of somatosensory hypersensitivity. The highest dose of intraperitoneal pioglitazone did not produce ataxia or reductions in transient mechanical and heat nociception, indicating that inhibitory effects on hypersensitivity were not secondary to adverse drug-induced behaviors or antinociception. Inhibitory effects on hypersensitivity persisted at least one week beyond cessation of pioglitazone administration, suggestive of long-lasting effects on gene expression. Blockade of PPARγ with GW9662, an irreversible and selective PPARγ antagonist, dose-dependently reduced the inhibitory effect of pioglitazone on hypersensitivity, indicating a PPARγ-dependent action. Remarkably, a single preemptive injection of pioglitazone 15 min before SNI attenuated hypersensitivity for at least 2 weeks; this was enhanced with a second injection delivered 12 h after SNI. Pioglitazone injections beginning after SNI also reduced hypersensitivity, albeit to a lesser degree than preemptive treatment. Intraperitoneal pioglitazone significantly reduced the nerve injury-induced up-regulation of cd11b, GFAP, and p-p38 in the dorsal horn, indicating a mechanism of action involving spinal microglia and/or astrocyte activation. Oral pioglitazone significantly reduced touch stimulus-evoked phospho-extracellular signal-related kinase (p-ERK) in lamina I-II, indicating a mechanism of action involving inhibition of central sensitization. We conclude that pioglitazone reduces spinal glial and stimulus-evoked p-ERK activation and that PPARγ activation blocks the development of and reduces established neuropathic pain.
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Affiliation(s)
- J Morgenweck
- Department of Physiology, University of Kentucky Research Foundation, Lexington, KY 40536, USA
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Morgenweck J, Abdel-Aleem OS, McNamara KC, Donahue RR, Badr MZ, Taylor BK. Activation of peroxisome proliferator-activated receptor gamma in brain inhibits inflammatory pain, dorsal horn expression of Fos, and local edema. Neuropharmacology 2009; 58:337-45. [PMID: 19891980 DOI: 10.1016/j.neuropharm.2009.10.008] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Revised: 10/27/2009] [Accepted: 10/27/2009] [Indexed: 11/16/2022]
Abstract
Systemic administration of thiazolidinediones reduces peripheral inflammation in vivo, presumably by acting at peroxisome proliferator-activated receptor gamma (PPARgamma) in peripheral tissues. Based on a rapidly growing body of literature indicating the CNS as a functional target of PPARgamma actions, we postulated that brain PPARgamma modulates peripheral edema and the processing of inflammatory pain signals in the dorsal horn of the spinal cord. To test this in the plantar carrageenan model of inflammatory pain, we measured paw edema, heat hyperalgesia, and dorsal horn expression of the immediate-early gene c-fos after intracerebroventricular (ICV) administration of PPARgamma ligands or vehicle. We found that ICV rosiglitazone (0.5-50 microg) or 15d-PGJ(2) (50-200 microg), but not vehicle, dose-dependently reduced paw thickness, paw volume and behavioral withdrawal responses to noxious heat. These anti-inflammatory and anti-hyperalgesia effects result from direct actions in the brain and not diffusion to other sites, because intraperitoneal and intrathecal administration of rosiglitazone (50 microg) and 15d-PGJ(2) (200 microg) had no effect. PPARgamma agonists changed neither overt behavior nor motor coordination, indicating that non-specific behavioral effects do not contribute to PPAR ligand-induced anti-hyperalgesia. ICV administration of structurally dissimilar PPARgamma antagonists (either GW9662 or BADGE) reversed the anti-inflammatory and anti-hyperalgesic actions of both rosiglitazone and 15d-PGJ(2). To evaluate the effects of PPARgamma agonists on a classic marker of noxious stimulus-evoked gene expression, we quantified Fos protein expression in the dorsal horn. The number of carrageenan-induced Fos-like immunoreactive profiles was less in rosiglitazone-treated rats as compared to vehicle controls. We conclude that pharmacological activation of PPARgamma in the brain rapidly inhibits local edema and the spinal transmission of noxious inflammatory signals.
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Affiliation(s)
- J Morgenweck
- Department of Pharmacology, Tulane University Health Sciences Center, New Orleans, LA 70112, USA
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Donahue RR, LaGraize SC, Fuchs PN. Electrolytic lesion of the anterior cingulate cortex decreases inflammatory, but not neuropathic nociceptive behavior in rats. Brain Res 2001; 897:131-8. [PMID: 11282366 DOI: 10.1016/s0006-8993(01)02103-5] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The present study investigated the effect of lesions of the anterior cingulate cortex (ACC) on mechanical allodynia/hyperalgesia after L5 ligation or on inflammatory nociceptive responses following formalin injection in the rat. For both the neuropathic and inflammatory pain models, three groups of animals were used. The control groups consisted of a group of sham lesioned animals and a group of animals that had unilateral damage to the ACC or unilateral/bilateral damage to surrounding cortical tissue. The third group consisted of animals that had at least 75% bilateral damage of the ACC. Subjects received L5 ligation or a 0.05-ml injection of 1% formalin into the plantar surface of the hindpaw. In contrast to the control groups, bilateral ACC lesions significantly decreased inflammatory nociceptive responses during the prolonged, tonic portion of the formalin test (20-35 min). The difference between the groups was most prevalent in the amount of time spent licking the paw. However, ACC lesions did not significantly attenuate the enhanced mechanical paw withdrawal threshold in the neuropathic nociceptive model. These results suggest a differential role of the ACC in the modulation of different types of pain conditions.
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Affiliation(s)
- R R Donahue
- Department of Psychology, University of Texas at Arlington, Box 19528, Arlington, TX 76019, USA
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