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Kuo HC, Chen SL, Chiu SC, Lee KF, Chu CH. Tolerized Microglia Protect Neurons Against Endotoxin-Induced TNF-α Production via an LBP-Dependent Intracellular p38 MAPK Signaling Pathway. Inflammation 2023; 46:2011-2023. [PMID: 37365417 DOI: 10.1007/s10753-023-01858-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Revised: 06/12/2023] [Accepted: 06/12/2023] [Indexed: 06/28/2023]
Abstract
The development of microglial endotoxin tolerance (ET) is a critical event in protecting neurons against excessive immune responses when microglia are administered two consecutive lipopolysaccharide (LPS) challenges. However, the intrinsic mechanisms of microglia shape ET programs and protect neurons remain unclear. This study aimed to determine whether extracellular autocrine cascades or intracellular signaling pathways are involved in ET microglia-mediated tumor necrosis factor-alpha (TNF-α) reduction and neuroprotection. Neuron-glia cultures composed of astroglia, neurons, and microglia were performed in different conditions: with or without serum or LPS-binding proteins (LBP), along with an induction approach of ET. Enzyme-linked immunosorbent assay results revealed that LPS induced TNF-α tolerance of microglia in an LBP-dependent manner. Furthermore, we determined whether the early pro-inflammatory cytokines induced by LPS might contribute to the development of microglial ET. Our data showed that the neutralization of TNF-α using an anti-TNF-α antibody had no change in the TNF-α tolerance of microglia during the ET challenge. Furthermore, pre-incubation of TNF-α, interleukin-1 beta, and prostaglandin E2 failed to induce any TNF-α tolerance in microglia after LPS treatment. Moreover, using three specific chemical inhibitors that respectively blocked the activities of the mitogen-activated protein kinases (MAPKs) namely p38, c-Jun N-terminal kinase and extracellular signal-related kinases revealed that inhibition of p38 MAPK by SB203580 disrupted the tolerated microglia-mediated TNF-α reduction and neuroprotection. In summary, our findings demonstrated that the LPS pre-treatment immediately programmed the microglial ET to prevent endotoxin-induced TNF-α production and neuronal damage through the intracellular p38 MAPK signaling pathway.
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Affiliation(s)
- Hsing-Chun Kuo
- Department of Nursing, Division of Basic Medical Sciences, Chang Gung University of Science and Technology, Chiayi, Taiwan
- Research Fellow, Chang Gung Memorial Hospital, Chiayi, Taiwan
- Research Center for Food and Cosmetic Safety, College of Human Ecology, Chang Gung University of Science and Technology, Taoyuan, Taiwan
- Chronic Diseases and Health Promotion Research Center, Chang Gung University of Science and Technology, Chiayi, Taiwan
| | - Shiou-Lan Chen
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University (KMU), Kaohsiung, Taiwan
| | - Shu-Chen Chiu
- National Laboratory Animal Center (NLAC), NARLabs, Tainan, Taiwan
| | - Kam-Fai Lee
- Department of Pathology, Chang Gung Memorial Hospital, Chiayi, 61363, Taiwan
| | - Chun-Hsien Chu
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, 3F, No.367, Sheng-Li Rd, North District, Tainan City 704, Taiwan.
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Kaburagi H, Nagata T, Enomoto M, Hirai T, Ohyagi M, Ihara K, Yoshida-Tanaka K, Ebihara S, Asada K, Yokoyama H, Okawa A, Yokota T. Systemic DNA/RNA heteroduplex oligonucleotide administration for regulating the gene expression of dorsal root ganglion and sciatic nerve. MOLECULAR THERAPY - NUCLEIC ACIDS 2022; 28:910-919. [PMID: 35694210 PMCID: PMC9167871 DOI: 10.1016/j.omtn.2022.05.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 05/03/2022] [Indexed: 11/24/2022]
Abstract
Neuropathic pain, a heterogeneous condition, affects 7%–10% of the general population. To date, efficacious and safe therapeutic approaches remain limited. Antisense oligonucleotide (ASO) therapy has opened the door to treat spinal muscular atrophy, with many ongoing clinical studies determining its therapeutic utility. ASO therapy for neuropathic pain and peripheral nerve disease requires efficient gene delivery and knockdown in both the dorsal root ganglion (DRG) and sciatic nerve, key tissues for pain signaling. We previously developed a new DNA/RNA heteroduplex oligonucleotide (HDO) technology that achieves highly efficient gene knockdown in the liver. Here, we demonstrated that intravenous injection of HDO, comprising an ASO and its complementary RNA conjugated to α-tocopherol, silences endogenous gene expression more than 2-fold in the DRG, and sciatic nerve with higher potency, efficacy, and broader distribution than ASO alone. Of note, we observed drastic target suppression in all sizes of neuronal DRG populations by in situ hybridization. Our findings establish HDO delivery as an investigative and potentially therapeutic platform for neuropathic pain and peripheral nerve disease.
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Abstract
The genetic basis for most inherited neurodegenerative diseases has been identified, yet there are limited disease-modifying therapies for these patients. A new class of drugs-antisense oligonucleotides (ASOs)-show promise as a therapeutic platform for treating neurological diseases. ASOs are designed to bind to the RNAs either by promoting degradation of the targeted RNA or by elevating expression by RNA splicing. Intrathecal injection into the cerebral spinal fluid results in broad distribution of antisense drugs and long-term effects. Approval of nusinersen in 2016 demonstrated that effective treatments for neurodegenerative diseases can be identified and that treatments not only slow disease progression but also improve some symptoms. Antisense drugs are currently in development for amyotrophic lateral sclerosis, Huntington's disease, Alzheimer's disease, Parkinson's disease, and Angelman syndrome, and several drugs are in late-stage research for additional neurological diseases. This review highlights the advances in antisense technology as potential treatments for neurological diseases.
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Affiliation(s)
- C Frank Bennett
- Ionis Pharmaceuticals Inc., Carlsbad, California 92010, USA;
| | | | - Don W Cleveland
- Ludwig Institute for Cancer Research and Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, California 92093, USA
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Asih PR, Prikas E, Stefanoska K, Tan ARP, Ahel HI, Ittner A. Functions of p38 MAP Kinases in the Central Nervous System. Front Mol Neurosci 2020; 13:570586. [PMID: 33013322 PMCID: PMC7509416 DOI: 10.3389/fnmol.2020.570586] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 08/18/2020] [Indexed: 12/22/2022] Open
Abstract
Mitogen-activated protein (MAP) kinases are a central component in signaling networks in a multitude of mammalian cell types. This review covers recent advances on specific functions of p38 MAP kinases in cells of the central nervous system. Unique and specific functions of the four mammalian p38 kinases are found in all major cell types in the brain. Mechanisms of p38 activation and downstream phosphorylation substrates in these different contexts are outlined and how they contribute to functions of p38 in physiological and under disease conditions. Results in different model organisms demonstrated that p38 kinases are involved in cognitive functions, including functions related to anxiety, addiction behavior, neurotoxicity, neurodegeneration, and decision making. Finally, the role of p38 kinases in psychiatric and neurological conditions and the current progress on therapeutic inhibitors targeting p38 kinases are covered and implicate p38 kinases in a multitude of CNS-related physiological and disease states.
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Affiliation(s)
- Prita R Asih
- Dementia Research Centre, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia
| | - Emmanuel Prikas
- Dementia Research Centre, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia
| | - Kristie Stefanoska
- Dementia Research Centre, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia
| | - Amanda R P Tan
- Dementia Research Centre, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia
| | - Holly I Ahel
- Dementia Research Centre, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia
| | - Arne Ittner
- Dementia Research Centre, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia
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Gonçalves dos Santos G, Delay L, Yaksh TL, Corr M. Neuraxial Cytokines in Pain States. Front Immunol 2020; 10:3061. [PMID: 32047493 PMCID: PMC6997465 DOI: 10.3389/fimmu.2019.03061] [Citation(s) in RCA: 82] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 12/16/2019] [Indexed: 12/11/2022] Open
Abstract
A high-intensity potentially tissue-injuring stimulus generates a homotopic response to escape the stimulus and is associated with an affective phenotype considered to represent pain. In the face of tissue or nerve injury, the afferent encoding systems display robust changes in the input-output function, leading to an ongoing sensation reported as painful and sensitization of the nociceptors such that an enhanced pain state is reported for a given somatic or visceral stimulus. Our understanding of the mechanisms underlying this non-linear processing of nociceptive stimuli has led to our appreciation of the role played by the functional interactions of neural and immune signaling systems in pain phenotypes. In pathological states, neural systems interact with the immune system through the actions of a variety of soluble mediators, including cytokines. Cytokines are recognized as important mediators of inflammatory and neuropathic pain, supporting system sensitization and the development of a persistent pathologic pain. Cytokines can induce a facilitation of nociceptive processing at all levels of the neuraxis including supraspinal centers where nociceptive input evokes an affective component of the pain state. We review here several key proinflammatory and anti-inflammatory cytokines/chemokines and explore their underlying actions at four levels of neuronal organization: (1) peripheral nociceptor termini; (2) dorsal root ganglia; (3) spinal cord; and (4) supraspinal areas. Thus, current thinking suggests that cytokines by this action throughout the neuraxis play key roles in the induction of pain and the maintenance of the facilitated states of pain behavior generated by tissue injury/inflammation and nerve injury.
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Affiliation(s)
| | - Lauriane Delay
- Department of Anesthesiology, University of California, San Diego, La Jolla, CA, United States
| | - Tony L. Yaksh
- Department of Anesthesiology, University of California, San Diego, La Jolla, CA, United States
| | - Maripat Corr
- Division of Rheumatology, Allergy and Immunology, University of California, San Diego, La Jolla, CA, United States
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6
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Antisense oligonucleotides selectively suppress target RNA in nociceptive neurons of the pain system and can ameliorate mechanical pain. Pain 2019; 159:139-149. [PMID: 28976422 DOI: 10.1097/j.pain.0000000000001074] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
There is an urgent need for better treatments for chronic pain, which affects more than 1 billion people worldwide. Antisense oligonucleotides (ASOs) have proven successful in treating children with spinal muscular atrophy, a severe infantile neurological disorder, and several ASOs are currently being tested in clinical trials for various neurological disorders. Here, we characterize the pharmacodynamic activity of ASOs in spinal cord and dorsal root ganglia (DRG), key tissues for pain signaling. We demonstrate that activity of ASOs lasts up to 2 months after a single intrathecal bolus dose. Interestingly, comparison of subcutaneous, intracerebroventricular, and intrathecal administration shows that DRGs are targetable by systemic and central delivery of ASOs, while target reduction in the spinal cord is achieved only after direct central delivery. Upon detailed characterization of ASO activity in individual cell populations in DRG, we observe robust target suppression in all neuronal populations, thereby establishing that ASOs are effective in the cell populations involved in pain propagation. Furthermore, we confirm that ASOs are selective and do not modulate basal pain sensation. We also demonstrate that ASOs targeting the sodium channel Nav1.7 induce sustained analgesia up to 4 weeks. Taken together, our findings support the idea that ASOs possess the required pharmacodynamic properties, along with a long duration of action beneficial for treating pain.
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Qiu Q, Sun L, Wang XM, Lo ACY, Wong KL, Gu P, Wong SCS, Cheung CW. Propofol produces preventive analgesia via GluN2B-containing NMDA Receptor/ERK1/2 Signaling Pathway in a rat model of inflammatory pain. Mol Pain 2018; 13:1744806917737462. [PMID: 28969472 PMCID: PMC5644366 DOI: 10.1177/1744806917737462] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Abstract Propofol, an intravenous anesthetic, has been shown to offer superior analgesic effect clinically. Whether propofol has preventive analgesic property remains unexplored. The present study investigated the antinociceptive effect of propofol and underlying molecular and cellular mechanisms via pre-emptive administration in a formalin-induced inflammatory pain model in rats. Male adult Sprague–Dawley rats were randomly allocated into four groups: naïve (Group Naïve), formalin injection only (Group Formalin), and formalin injection at 30 min (Group P-30 min) or 2 h (Group P-2 h) after intravenous infusion of propofol (0.6 mg kg−1 min−1) for 1 h. Nociceptive responses and protein expression of phosphorylated- or pan-GluN2B, ERK1/2, p38 mitogen-activated protein kinase, and c-Jun N-terminal kinase in the spinal dorsal horn were evaluated. Alteration of intracellular Ca2+ concentration induced by N-methyl-D-aspartate (NMDA) receptor agonists with or without pre-treatment of propofol was measured using fluorometry in SH-SY5Y cells while neuronal activation in the spinal dorsal horn by immunofluorescence. Pre-emptive propofol reduced pain with a delayed response to formalin and a reduction in hypersensitivity that lasted at least for 2 h. The formalin-induced activation of spinal GluN2B and ERK1/2 but not p38 or c-Jun N-terminal kinase was also diminished by propofol treatment. Preconditioning treatment with 3 µM and 10 µM of propofol inhibited Ca2+ influx mediated through NMDA receptors in SH-SY5Y cells. Propofol also reduced the neuronal expression of c-Fos and p-ERK induced by formalin. This study shows that pre-emptive administration of propofol produces preventive analgesic effects on inflammatory pain through regulating neuronal GluN2B-containing NMDA receptor and ERK1/2 pathway in the spinal dorsal horn.
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Affiliation(s)
- Qiu Qiu
- Laboratory and Clinical Research Institute for Pain, Department of Anaesthesiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Liting Sun
- Laboratory and Clinical Research Institute for Pain, Department of Anaesthesiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Xiao-Min Wang
- Laboratory and Clinical Research Institute for Pain, Department of Anaesthesiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Amy C Y Lo
- Department of Ophthalmology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Kar Lok Wong
- Department of Anesthesiology, and Institute of Clinical Medical Sciences, and Research Group of Cardiovascular Biology, China Medical University and Hospital, Taichung, Taiwan
| | - Pan Gu
- Laboratory and Clinical Research Institute for Pain, Department of Anaesthesiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Sau Ching Stanley Wong
- Laboratory and Clinical Research Institute for Pain, Department of Anaesthesiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
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Luo X, Fitzsimmons B, Mohan A, Zhang L, Terrando N, Kordasiewicz H, Ji RR. Intrathecal administration of antisense oligonucleotide against p38α but not p38β MAP kinase isoform reduces neuropathic and postoperative pain and TLR4-induced pain in male mice. Brain Behav Immun 2018; 72:34-44. [PMID: 29128611 PMCID: PMC5940592 DOI: 10.1016/j.bbi.2017.11.007] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2017] [Revised: 10/27/2017] [Accepted: 11/08/2017] [Indexed: 02/06/2023] Open
Abstract
p38 mitogen-activated protein kinase (MAPK) consists of two major isoforms: p38α and p38β; however, it remains unclear which isoform is more important for chronic pain development. Recently, we developed potent, long-lasting, and p38 MAPK subtype-specific antisense oligonucleotides (ASOs). We examined the therapeutic effects of isoform-specific ASOs in several chronic pain models following single intrathecal injection (300 μg/10 μl) in CD1 mice. In the chronic constriction injury (CCI) model, p38α MAPK ASO, given on post-operative day 5, reduced CCI-induced mechanical allodynia in male but not female mice. In contrast, mechanical allodynia after CCI in both sexes was not affected by p38β MAPK ASO. Intrathecal injection of p38α or p38β ASO resulted in a partial reduction (≈ 50%) of spinal p38α or p38β mRNA level, respectively, in both sexes at two weeks. In contrast, intrathecal injection of the ASOs did not affect p38α and p38β MAPK mRNA levels in dorsal root ganglia. Intrathecal p38α ASO also reduced postoperative pain (mechanical and cold allodynia) in male mice after tibia fracture. However, intrathecal p38α ASO had no effect on mechanical allodynia in male mice after paclitaxel treatment. Intrathecal p38α MAPK ASO pre-treatment also prevented TLR4-mediated mechanical allodynia and downregulated levels of p38α MAPK and phosphorylated p38 MAPK following intrathecal treatment of lipopolysaccharide. In summary, our findings suggest that p38α MAPK is the major p38 MAPK isoform in the spinal cord and regulates chronic pain in a sex and model-dependent manner. Intrathecal p38α MAPK ASO may offer a new treatment for some chronic pain conditions.
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Affiliation(s)
- Xin Luo
- Department of Anesthesiology, Duke University Medical Center, Durham, NC 27710, United States.
| | | | - Apoorva Mohan
- Neuroscience Drug Discovery, Ionis Pharmaceuticals, Carlsbad, CA 92010
| | - Linlin Zhang
- Department of Anesthesiology, Duke University Medical Center, Durham, NC 27710
| | - Niccolo Terrando
- Department of Anesthesiology, Duke University Medical Center, Durham, NC 27710
| | | | - Ru-Rong Ji
- Department of Anesthesiology, Duke University Medical Center, Durham, NC 27710, United States; Department of Anesthesiology and Neurobiology, Duke University Medical Center, NC 27710, United States.
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Wu HY, Mao XF, Fan H, Wang YX. p38 β Mitogen-Activated Protein Kinase Signaling Mediates Exenatide-Stimulated Microglial β-Endorphin Expression. Mol Pharmacol 2017; 91:451-463. [PMID: 28202578 DOI: 10.1124/mol.116.107102] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 02/07/2017] [Indexed: 12/14/2022] Open
Abstract
Recent discoveries established that activation of glucagon-like peptide-1 receptors (GLP-1Rs) mediates neuroprotection and antinociception through microglial β-endorphin expression. This study aimed to explore the underlying signaling mechanisms of microglial β-endorphin. GLP-1Rs and β-endorphin were coexpressed in primary cultures of microglia. Treatment with the GLP-1R agonist exenatide concentration-dependently stimulated microglial expression of the β-endorphin precursor gene proopiomelanocortin (POMC) and peptides, with EC50 values of 4.1 and 7.5 nM, respectively. Exenatide also significantly increased intracellular cAMP levels and expression of p-protein kinase A (PKA), p-p38, and p-cAMP response element binding protein (CREB) in cultured primary microglia. Furthermore, exenatide-induced microglial expression of POMC was completely blocked by reagents that specifically inhibit adenylyl cyclase and activation of PKA, p38, and CREB. In addition, knockdown of p38β (but not p38α) using short interfering RNA (siRNA) eliminated exenatide-induced microglial p38 phosphorylation and POMC expression. In contrast, lipopolysaccharide increased microglial activation of p38, and knockdown of p38α (but not p38β) partially suppressed expression of proinflammatory factors (including tumor necrosis factor-α, interleukin-1β, and interleukin-6). Exenatide-induced phosphorylation of p38 and CREB was also totally blocked by the PKA inhibitor and siRNA/p38β, but not by siRNA/p38α Seven-day intrathecal injections of siRNA/p38β (but not siRNA/p38α) completely blocked exenatide-induced spinal p38 activation, β-endorphin expression, and mechanical antiallodynia in rats with established neuropathy, although siRNA/p38β and siRNA/p38α were not antiallodynic. To our knowledge, our results are the first to show a causal relationship between the PKA-dependent p38β mitogen-activated protein kinase/CREB signal cascade and GLP-1R agonism-mediated microglial β-endorphin expression. The differential role of p38α and p38β activation in inflammation and nociception was also highlighted.
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Affiliation(s)
- Hai-Yun Wu
- King's Laboratory, Shanghai Jiao Tong University School of Pharmacy, Shanghai, China
| | - Xiao-Fang Mao
- King's Laboratory, Shanghai Jiao Tong University School of Pharmacy, Shanghai, China
| | - Hui Fan
- King's Laboratory, Shanghai Jiao Tong University School of Pharmacy, Shanghai, China
| | - Yong-Xiang Wang
- King's Laboratory, Shanghai Jiao Tong University School of Pharmacy, Shanghai, China
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Yaksh TL, Fisher CJ, Hockman TM, Wiese AJ. Current and Future Issues in the Development of Spinal Agents for the Management of Pain. Curr Neuropharmacol 2017; 15:232-259. [PMID: 26861470 PMCID: PMC5412694 DOI: 10.2174/1570159x14666160307145542] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Revised: 12/02/2015] [Accepted: 02/05/2016] [Indexed: 11/22/2022] Open
Abstract
Targeting analgesic drugs for spinal delivery reflects the fact that while the conscious experience of pain is mediated supraspinally, input initiated by high intensity stimuli, tissue injury and/or nerve injury is encoded at the level of the spinal dorsal horn and this output informs the brain as to the peripheral environment. This encoding process is subject to strong upregulation resulting in hyperesthetic states and downregulation reducing the ongoing processing of nociceptive stimuli reversing the hyperesthesia and pain processing. The present review addresses the biology of spinal nociceptive processing as relevant to the effects of intrathecally-delivered drugs in altering pain processing following acute stimulation, tissue inflammation/injury and nerve injury. The review covers i) the major classes of spinal agents currently employed as intrathecal analgesics (opioid agonists, alpha 2 agonists; sodium channel blockers; calcium channel blockers; NMDA blockers; GABA A/B agonists; COX inhibitors; ii) ongoing developments in the pharmacology of spinal therapeutics focusing on less studied agents/targets (cholinesterase inhibition; Adenosine agonists; iii) novel intrathecal targeting methodologies including gene-based approaches (viral vectors, plasmids, interfering RNAs); antisense, and toxins (botulinum toxins; resniferatoxin, substance P Saporin); and iv) issues relevant to intrathecal drug delivery (neuraxial drug distribution), infusate delivery profile, drug dosing, formulation and principals involved in the preclinical evaluation of intrathecal drug safety.
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Affiliation(s)
- Tony L. Yaksh
- University of California, San Diego, Anesthesia Research Lab 0818, 9500 Gilman Dr. LaJolla, CA 92093, USA
| | - Casey J. Fisher
- University of California, San Diego, Anesthesia Research Lab 0818, 9500 Gilman Dr. LaJolla, CA 92093, USA
| | - Tyler M. Hockman
- University of California, San Diego, Anesthesia Research Lab 0818, 9500 Gilman Dr. LaJolla, CA 92093, USA
| | - Ashley J. Wiese
- University of California, San Diego, Anesthesia Research Lab 0818, 9500 Gilman Dr. LaJolla, CA 92093, USA
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Deng L, Zhang L, Zhao H, Song F, Chen G, Zhu H. The role of p38MAPK activation in spinal dorsal horn in remifentanil-induced postoperative hyperalgesia in rats. Neurol Res 2016; 38:929-36. [PMID: 27687719 DOI: 10.1080/01616412.2016.1219078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
OBJECTIVES Remifentanil may induce hyperalgesia. Recent studies implicate a close relationship between post-surgical hyperalgesia and phosphorylation and activation of p38 mitogen-activated protein kinase (p38MAPK) in the spinal microglia. This study aimed to investigate whether the combination of post-surgical and remifentanil-induced hyperalgesia worsens post-operative pain and whether phosphorylated p38MAPK (phospho-p38MAPK) in the spinal dorsal horn in rats is involved in remifentanil-induced postoperative hyperalgesia. METHODS Sprague-Dawley rats were randomly divided into six groups: control, incision only, remifentanil only, remifentanil + incision, remifentanil + incision + SB203580, and remifentanil + incision + DMSO. The p38MAPK inhibitor SB203580 and DMSO were injected intrathecally. A right plantar surgical incision was performed in the incision groups, and remifentanil was infused for 60 min in the remifentanil groups. Mechanical paw withdrawal threshold (PWT) and thermal paw withdrawal latency (PWL) of the bilateral hind paws were measured and the number of phospho-p38MAPK-positive cells in rat spinal dorsal horn sections was counted. RESULTS Intravenous remifentanil infusion decreased bilateral plantar PWL values from 1 h to 3 days after surgery, however there was no additive effect with incision-induced values. There was a significant increase in the number of dorsal horn phospho-p38MAPK-positive cells in the remifentanil + incision group compared to the incision group, but no increase in the number of these cells when remifentanil was given alone. Intrathecal pretreatment with SB203580 attenuated remifentanil + incision-induced postoperative hyperalgesia and significantly reduced activation of phospho-p38MAPK in spinal dorsal horn. CONCLUSIONS Incision-induced and remifentanil-induced increases in hyperalgesia were not additive when incision and remifentanil were used together. Data on phospho-38MAPK activation in remifenanil-induced hyperalgesia were contradictory and need further clarification.
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Affiliation(s)
- Liqin Deng
- a Department of Anesthesiology , General Hospital of Ningxia Medical University , Yinchuan City , China
| | - Lihua Zhang
- b Department of Anesthesiology , Beijing Fengtai Hospital of Integrated Traditional and Western Medicine , Beijing , China
| | - Haiying Zhao
- c Graduate School of Ningxia Medical University , Yinchuan City , China
| | - Fengxiang Song
- c Graduate School of Ningxia Medical University , Yinchuan City , China
| | - Gang Chen
- c Graduate School of Ningxia Medical University , Yinchuan City , China
| | - Hanyue Zhu
- c Graduate School of Ningxia Medical University , Yinchuan City , China
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12
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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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Aguilar-Alonso FA, Solano JD, Vargas-Olvera CY, Pacheco-Bernal I, Pariente-Pérez TO, Ibarra-Rubio ME. MAPKs’ status at early stages of renal carcinogenesis and tumors induced by ferric nitrilotriacetate. Mol Cell Biochem 2015; 404:161-70. [PMID: 25724684 DOI: 10.1007/s11010-015-2375-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Accepted: 02/23/2015] [Indexed: 12/12/2022]
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Dong H, Xiang HB, Ye DW, Tian XB. Inhibitory effects of intrathecal p38β antisense oligonucleotide on bone cancer pain in rats. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2014; 7:7690-7698. [PMID: 25550805 PMCID: PMC4270575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 10/18/2014] [Indexed: 06/04/2023]
Abstract
OBJECTIVE To evaluate the effects of intrathecal administration p38β antisense oligonucleotide on the development of bone cancer pain rats. METHODS Forty female SD rats weighing 180~220 g were randomly divided into 4 groups (n = 10 each): Group A (control group): intra-tibial injection of 3 μl Hank's solution; group B (model group): intra-tibial injection of 3 μl MADB-106 mammary gland carcinoma cells of rats (4.8 × 10(3)/μl); group C (p38β-SODN 20 μg); group D (p38β-ASODN 20 μg). The model procedures in group C and D were same to those in the group B. From the 14th day after operation, p38β-SODN 20 μg and p38β-ASODN 20 μg were respectively intrathecally administrated in group C and D once daily for 6 days whereas normal saline was for group A and B. Mechanical withdrawal threshold and radiant heat threshold of rat hind paws were measured before operation and every other day until 22 d of post-operation. The lumbar 4-6 spinal cord was removed on the 22(nd) day. The expression of spinal p38β protein was determined by Western blot. RESULTS No significant differences in mechanical withdrawal threshold and radiant heat threshold were found at all time points in control group. During the first 6 days after operation there were obvious differences in radiant heat stimulus between control group between the other groups (P < 0.05); During 14-22 days after operation, mechanical pain threshold and radiant heat threshold between p38β-SODN group and Model group were significantly changed compared with that in control group (P < 0.05). However, the differences were not remarkable between control group and p38β-ASODN group (P > 0.05). The expression of p38β protein in lumbar spinal cord was significantly higher between p38β-SODN group and Model group than that in control group (P < 0.05). There was no significant difference in p38β protein expression between p38β-ASODN group and control group (P > 0.05). CONCLUSIONS Hyperalgesia induced by bone cancer can be inhibited by intrathecal administration of p38β antisense oligonucleotide, which is achieved by reducing expression of p38β protein.
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Affiliation(s)
- Hang Dong
- Department of Anesthesiology, Affiliated Hospital, Jianghan UniversityWuhan 430072, P. R. China
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science & TechnologyWuhan 430030, P. R. China
| | - Hong-Bing Xiang
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science & TechnologyWuhan 430030, P. R. China
| | - Da-Wei Ye
- Cancer Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science & TechnologyWuhan 430030, P. R. China
| | - Xue-Bi Tian
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science & TechnologyWuhan 430030, P. R. China
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Fairbanks CA, Peterson CD, Speltz RH, Riedl MS, Kitto KF, Dykstra JA, Braun PD, Sadahiro M, Salton SR, Vulchanova L. The VGF-derived peptide TLQP-21 contributes to inflammatory and nerve injury-induced hypersensitivity. Pain 2014; 155:1229-1237. [PMID: 24657450 DOI: 10.1016/j.pain.2014.03.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 03/03/2014] [Accepted: 03/14/2014] [Indexed: 12/30/2022]
Abstract
VGF (nonacronymic) is a granin-like protein that is packaged and proteolytically processed within the regulated secretory pathway. VGF and peptides derived from its processing have been implicated in neuroplasticity associated with learning, memory, depression, and chronic pain. In sensory neurons, VGF is rapidly increased following peripheral nerve injury and inflammation. Several bioactive peptides generated from the C-terminus of VGF have pronociceptive spinal effects. The goal of the present study was to examine the spinal effects of the peptide TLQP-21 and determine whether it participates in spinal mechanisms of persistent pain. Application of exogenous TLQP-21 induced dose-dependent thermal hyperalgesia in the warm-water immersion tail-withdrawal test. This hyperalgesia was inhibited by a p38 mitogen-activated protein kinase inhibitor, as well as inhibitors of cyclooxygenase and lipoxygenase. We used immunoneutralization of TLQP-21 to determine the function of the endogenous peptide in mechanisms underlying persistent pain. In mice injected intradermally with complete Freund adjuvant, intrathecal treatment with anti-TLQP-21 immediately prior to or 5hours after induction of inflammation dose-dependently inhibited tactile hypersensitivity and thermal hyperalgesia. Intrathecal anti-TL21 administration also attenuated the development and maintenance of tactile hypersensitivity in the spared nerve injury model of neuropathic pain. These results provide evidence that endogenous TLQP-21 peptide contributes to the mechanisms of spinal neuroplasticity after inflammation and nerve injury.
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Affiliation(s)
- Carolyn A Fairbanks
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, USA Department of Pharmaceutics, University of Minnesota, Minneapolis, MN, USA Department of Pharmacology, University of Minnesota, Minneapolis, MN, USA Experimental and Clinical Pharmacology Graduate Program, University of Minnesota, Minneapolis, MN, USA Comparative and Molecular Biosciences Graduate Program, University of Minnesota, St. Paul, MN, USA Fishberg Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA Department of Veterinary and Biomedical Sciences, University of Minnesota, St. Paul, MN, USA
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16
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Moon JY, Roh DH, Yoon SY, Kang SY, Choi SR, Kwon SG, Choi HS, Han HJ, Beitz AJ, Lee JH. Sigma-1 receptor-mediated increase in spinal p38 MAPK phosphorylation leads to the induction of mechanical allodynia in mice and neuropathic rats. Exp Neurol 2013; 247:383-91. [PMID: 23333567 DOI: 10.1016/j.expneurol.2013.01.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Revised: 12/22/2012] [Accepted: 01/08/2013] [Indexed: 12/30/2022]
Abstract
The direct activation of the spinal sigma-1 receptor (Sig-1R) produces mechanical allodynia (MA) and thermal hyperalgesia (TH) in mice. In addition, the blockade of the spinal Sig-1R prevents the induction of MA, but not TH in chronic constriction injury (CCI)-induced neuropathic rats. The present study was designed to investigate whether the increase in spinal p38 MAPK phosphorylation (p-p38 MAPK) mediates Sig-1R-induced MA or TH in mice and the induction of MA in neuropathic rats. MA and TH were evaluated using von Frey filaments and a hot-plate apparatus, respectively. Neuropathic pain was produced by CCI of the right sciatic nerve in rats. Western blot assay and immunohistochemistry were performed to determine the changes of p-p38 MAPK expression in the spinal cord. Intrathecal (i.t.) injection of PRE084, a selective Sig-1R agonist, into naïve mice time-dependently increased the expression of p-p38 MAPK, which was blocked by pretreatment with BD1047, a Sig-1R antagonist. I.t. pretreatment with SB203580, a p38 MAPK inhibitor also dose-dependently inhibited PRE084-induced MA, whereas TH induction was not affected. In CCI rats, i.t. injection of BD1047 during the induction phase (postoperative days 0 to 5) reduced the CCI-induced increase in p-p38 MAPK. In addition, i.t. SB203580 treatment during the induction phase also suppressed the development of CCI-induced MA, but not TH. Conversely, i.t. SB203580 treatment during the maintenance phase (postoperative days 15 to 20) had no effect on CCI-induced MA or TH. These results demonstrate that the increase in spinal p-p38 MAPK is closely associated with the induction of Sig-1R mediated MA, but not TH. Sigma-1 receptor modulation of p-p38 MAPK also plays an important role in the induction, but not the maintenance, of MA in neuropathic pain.
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Affiliation(s)
- Ji-Young Moon
- Department of Veterinary Physiology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, Republic of Korea
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17
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Fang JQ, Du JY, Liang Y, Fang JF. Intervention of electroacupuncture on spinal p38 MAPK/ATF-2/VR-1 pathway in treating inflammatory pain induced by CFA in rats. Mol Pain 2013; 9:13. [PMID: 23517865 PMCID: PMC3608238 DOI: 10.1186/1744-8069-9-13] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Accepted: 03/18/2013] [Indexed: 12/21/2022] Open
Abstract
Background Previous studies have demonstrated that p38 MAPK signal transduction pathway plays an important role in the development and maintenance of inflammatory pain. Electroacupuncture (EA) can suppress the inflammatory pain. However, the relationship between EA effect and p38 MAPK signal transduction pathway in inflammatory pain remains poorly understood. It is our hypothesis that p38 MAPK/ATF-2/VR-1 and/or p38 MAPK/ATF-2/COX-2 signal transduction pathway should be activated by inflammatory pain in CFA-injected model. Meanwhile, EA may inhibit the activation of p38 MAPK signal transduction pathway. The present study aims to investigate that anti-inflammatory and analgesic effect of EA and its intervention on the p38 MAPK signal transduction pathway in a rat model of inflammatory pain. Results EA had a pronounced anti-inflammatory and analgesic effect on CFA-induced chronic inflammatory pain in rats. EA could quickly raise CFA-rat’s paw withdrawal thresholds (PWTs) and maintain good and long analgesic effect, while it subdued the ankle swelling of CFA rats only at postinjection day 14. EA could down-regulate the protein expressions of p-p38 MAPK and p-ATF-2, reduced the numbers of p-p38 MAPK-IR cells and p-ATF-2-IR cells in spinal dorsal horn in CFA rats, inhibited the expressions of both protein and mRNA of VR-1, but had no effect on the COX-2 mRNA expression. Conclusions The present study indicates that inhibiting the activation of spinal p38 MAPK/ATF-2/VR-1 pathway may be one of the main mechanisms via central signal transduction pathway in the process of anti-inflammatory pain by EA in CFA rats.
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Affiliation(s)
- Jian-Qiao Fang
- Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University, 548 Binwen Road, Binjiang District, Hangzhou, Zhejiang Province 310053, China.
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18
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Xing B, Bachstetter AD, Van Eldik LJ. Deficiency in p38β MAPK fails to inhibit cytokine production or protect neurons against inflammatory insult in in vitro and in vivo mouse models. PLoS One 2013; 8:e56852. [PMID: 23457629 PMCID: PMC3574114 DOI: 10.1371/journal.pone.0056852] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2012] [Accepted: 01/15/2013] [Indexed: 12/22/2022] Open
Abstract
The p38 MAPK pathway plays a key role in regulating the production of proinflammatory cytokines, such as TNFα and IL-1β, in peripheral inflammatory disorders. There are four major isoforms of p38 MAPK (p38α, β, δ, γ), with p38α and p38β the targets of most p38 MAPK inhibitor drugs. Our previous studies demonstrated that the p38α MAPK isoform is an important contributor to stressor-induced proinflammatory cytokine up-regulation and neurotoxicity in the brain. However, the potential role of the p38β MAPK isoform in CNS proinflammatory cytokine overproduction and neurotoxicity is poorly understood. In the current studies, we used primary microglia from wild type (WT) and p38β knockout (KO) mice in co-culture with WT neurons, and measured proinflammatory cytokines and neuron death after LPS insult. We also measured neuroinflammatory responses in vivo in WT and p38β KO mice after administration of LPS by intraperitoneal or intracerebroventricular injection. WT and p38β KO microglia/neuron co-cultures showed similar levels of TNFα and IL-1β production in response to LPS treatment, and no differences in LPS-induced neurotoxicity. The in vitro results were confirmed in vivo, where levels of TNFα and IL-1β in the CNS were not significantly different between WT or p38β KO mice after LPS insult. Our results suggest that, similar to peripheral inflammation, p38α is critical but p38β MAPK is dispensable in the brain in regards to proinflammatory cytokine production and neurotoxicity induced by LPS inflammatory insult.
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Affiliation(s)
- Bin Xing
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky, United States of America
| | - Adam D. Bachstetter
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky, United States of America
| | - Linda J. Van Eldik
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky, United States of America
- Department of Anatomy and Neurobiology, College of Medicine, University of Kentucky, Lexington, Kentucky, United States of America
- * E-mail:
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19
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Ostenfeld T, Krishen A, Lai RY, Bullman J, Baines AJ, Green J, Anand P, Kelly M. Analgesic efficacy and safety of the novel p38 MAP kinase inhibitor, losmapimod, in patients with neuropathic pain following peripheral nerve injury: a double-blind, placebo-controlled study. Eur J Pain 2012; 17:844-57. [PMID: 23239139 DOI: 10.1002/j.1532-2149.2012.00256.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/06/2012] [Indexed: 12/30/2022]
Abstract
BACKGROUND Inhibitors of p38 mitogen-activated protein kinase are undergoing evaluation as a novel class of anti-rheumatic drugs, by virtue of their ability to suppress the production of pro-inflammatory cytokines. Emerging data suggests that they may also attenuate peripheral or central sensitization in neuropathic pain. A double-blind, placebo-controlled study was undertaken to evaluate the analgesic efficacy of losmapimod (GW856553), a novel p38α/β inhibitor, in subjects with neuropathic pain following traumatic peripheral nerve injury. METHODS One hundred and sixty-eight subjects with pain of at least moderate intensity (average daily score ≥4 on an 11-point pain intensity numeric rating scale; PI-NRS) at baseline were randomized to receive oral losmapimod, 7.5 mg BID or placebo for 28 days. Efficacy and safety assessments were undertaken at weekly clinic visits. RESULTS The mean treatment difference for the change in average daily pain score from baseline to week 4 of treatment based on the PI-NRS was -0.22 (95% CI -0.73, 0.28) in favour of losmapimod over placebo (p = 0.39). There were no statistically significant or clinically meaningful differences between the treatment groups over the 4-week dosing period for either the primary or secondary efficacy variables. There were no unexpected safety or tolerability findings following dosing with losmapimod. CONCLUSIONS Losmapimod could not be differentiated from placebo in terms of a primary analgesia response in patients with pain following peripheral nerve injury. The lack of response could reflect inadequate exposure at central sites of action or differences between rodent and human with respect to the target or neuropathic pain mechanisms.
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Affiliation(s)
- T Ostenfeld
- Neurosciences Discovery Medicine Unit, GlaxoSmithKline R&D, Harlow, UK.
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20
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Acetic acid- and phenyl-p-benzoquinone-induced overt pain-like behavior depends on spinal activation of MAP kinases, PI3K and microglia in mice. Pharmacol Biochem Behav 2012; 101:320-8. [DOI: 10.1016/j.pbb.2012.01.018] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2011] [Revised: 11/30/2011] [Accepted: 01/22/2012] [Indexed: 11/17/2022]
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Ma MT, Yeo JF, Shui G, Wenk M, Ong WY. Systems wide analyses of lipids in the brainstem during inflammatory orofacial pain - Evidence of increased phospholipase A2 activity. Eur J Pain 2012; 16:38-48. [DOI: 10.1016/j.ejpain.2011.06.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- M.-T. Ma
- Department of Oral and Maxillofacial Surgery; National University of Singapore; Singapore
| | - J.-F. Yeo
- Department of Oral and Maxillofacial Surgery; National University of Singapore; Singapore
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22
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Carvalho TT, Flauzino T, Otaguiri ES, Batistela AP, Zarpelon AC, Cunha TM, Ferreira SH, Cunha FQ, Verri WA. Granulocyte-colony stimulating factor (G-CSF) induces mechanical hyperalgesia via spinal activation of MAP kinases and PI3K in mice. Pharmacol Biochem Behav 2011; 98:188-95. [PMID: 21236293 DOI: 10.1016/j.pbb.2010.12.027] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Revised: 12/16/2010] [Accepted: 12/23/2010] [Indexed: 11/18/2022]
Abstract
Granulocyte-colony stimulating factor (G-CSF) is a current pharmacological approach to increase peripheral neutrophil counts after anti-tumor therapies. Pain is most relevant side effect of G-CSF in healthy volunteers and cancer patients. Therefore, the mechanisms of G-CSF-induced hyperalgesia were investigated focusing on the role of spinal mitogen-activated protein (MAP) kinases ERK (extracellular signal-regulated kinase), JNK (Jun N-terminal Kinase) and p38, and PI(3)K (phosphatidylinositol 3-kinase). G-CSF induced dose (30-300 ng/paw)-dependent mechanical hyperalgesia, which was inhibited by local post-treatment with morphine. This effect of morphine was reversed by naloxone (opioid receptor antagonist). Furthermore, G-CSF-induced hyperalgesia was inhibited in a dose-dependent manner by intrathecal pre-treatment with ERK (PD98059), JNK (SB600125), p38 (SB202190) or PI(3)K (wortmanin) inhibitors. The co-treatment with MAP kinase and PI(3)K inhibitors, at doses that were ineffective as single treatment, significantly inhibited G-CSF-induced hyperalgesia. Concluding, in addition to systemic opioids, peripheral opioids as well as spinal treatment with MAP kinases and PI(3)K inhibitors also reduce G-CSF-induced pain.
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Affiliation(s)
- Thacyana T Carvalho
- Departamento de Patologia, Centro de Ciências Biológicas, Universidade Estadual de Londrina, Rod. Celso Garcia Cid KM480 PR445, CEP 86051-990, Cx Postal 6001, Londrina, Paraná, Brazil
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A p38 mitogen-activated protein kinase-dependent mechanism of disinhibition in spinal synaptic transmission induced by tumor necrosis factor-alpha. J Neurosci 2010; 30:12844-55. [PMID: 20861388 DOI: 10.1523/jneurosci.2437-10.2010] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Tumor necrosis factor-α (TNFα) is a proinflammatory cytokine that contributes to inflammatory and neuropathic pain. The mechanism by which TNFα modulates synaptic transmission in mouse substantia gelatinosa was studied using whole-cell patch clamp and immunohistochemistry. TNFα was confirmed to significantly increase the frequency of spontaneous EPSCs (sEPSCs) in spinal neurons and to also produce a robust decrease in the frequency of spontaneous IPSCs (sIPSCs). The enhancement of excitatory synaptic transmission by TNFα is in fact observed to be dependent on the suppression of sIPSCs, or disinhibition, in that blockade of inhibitory synaptic transmission prevents the effect of TNFα on sEPSCs but not vice versa. TNFα-induced inhibition of sIPSCs was blocked by neutralizing antibodies to TNF receptor 1 (TNFR1) but not to TNFR2 and was abolished by the p38 mitogen-activated protein kinase inhibitor SB202190 [4-(4-fluorophenyl)-2-(4-hydroxyphenyl)-5-(4-pyridyl)1H-imidazole]. TNFα rapidly inhibited spontaneous action potentials in GABAergic neurons identified in transgenic mice expressing enhanced green fluorescent protein controlled by the GAD67 promoter. This inhibitory effect was also blocked by intracellular delivery of SB202190 to the targeted cells. The inhibition of spontaneous activity in GABAergic neurons by TNFα is shown as mediated by a reduction in the hyperpolarization-activated cation current (Ih). These results suggest a novel TNFα-TNFR1-p38 pathway in spinal GABAergic neurons that may contribute to the development of neuropathic and inflammatory pain by TNFα.
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NADPH oxidase 2-derived reactive oxygen species in spinal cord microglia contribute to peripheral nerve injury-induced neuropathic pain. Proc Natl Acad Sci U S A 2010; 107:14851-6. [PMID: 20679217 DOI: 10.1073/pnas.1009926107] [Citation(s) in RCA: 179] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Increasing evidence supports the notion that spinal cord microglia activation plays a causal role in the development of neuropathic pain after peripheral nerve injury; yet the mechanisms for microglia activation remain elusive. Here, we provide evidence that NADPH oxidase 2 (Nox2)-derived ROS production plays a critical role in nerve injury-induced spinal cord microglia activation and subsequent pain hypersensitivity. Nox2 expression was induced in dorsal horn microglia immediately after L5 spinal nerve transection (SNT). Studies using Nox2-deficient mice show that Nox2 is required for SNT-induced ROS generation, microglia activation, and proinflammatory cytokine expression in the spinal cord. SNT-induced mechanical allodynia and thermal hyperalgesia were similarly attenuated in Nox2-deficient mice. In addition, reducing microglial ROS level via intrathecal sulforaphane administration attenuated mechanical allodynia and thermal hyperalgesia in SNT-injured mice. Sulforaphane also inhibited SNT-induced proinflammatory gene expression in microglia, and studies using primary microglia indicate that ROS generation is required for proinflammatory gene expression in microglia. These studies delineate a pathway involving nerve damage leading to microglial Nox2-generated ROS, resulting in the expression of proinflammatory cytokines that are involved in the initiation of neuropathic pain.
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