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Barry AM, Zhao N, Yang X, Bennett DL, Baskozos G. Deep RNA-seq of male and female murine sensory neuron subtypes after nerve injury. Pain 2023; 164:2196-2215. [PMID: 37318015 PMCID: PMC10502896 DOI: 10.1097/j.pain.0000000000002934] [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: 12/16/2022] [Revised: 01/27/2023] [Accepted: 02/05/2023] [Indexed: 06/16/2023]
Abstract
ABSTRACT Dorsal root ganglia (DRG) neurons have been well described for their role in driving both acute and chronic pain. Although nerve injury is known to cause transcriptional dysregulation, how this differs across neuronal subtypes and the impact of sex is unclear. Here, we study the deep transcriptional profiles of multiple murine DRG populations in early and late pain states while considering sex. We have exploited currently available transgenics to label numerous subpopulations for fluorescent-activated cell sorting and subsequent transcriptomic analysis. Using bulk tissue samples, we are able to circumvent the issues of low transcript coverage and drop-outs seen with single-cell data sets. This increases our power to detect novel and even subtle changes in gene expression within neuronal subtypes and discuss sexual dimorphism at the neuronal subtype level. We have curated this resource into an accessible database for other researchers ( https://livedataoxford.shinyapps.io/drg-directory/ ). We see both stereotyped and unique subtype signatures in injured states after nerve injury at both an early and late timepoint. Although all populations contribute to a general injury signature, subtype enrichment changes can also be seen. Within populations, there is not a strong intersection of sex and injury, but previously unknown sex differences in naïve states-particularly in Aβ-RA + Aδ-low threshold mechanoreceptors-still contribute to differences in injured neurons.
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Affiliation(s)
- Allison M. Barry
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Na Zhao
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Xun Yang
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - David L. Bennett
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Georgios Baskozos
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
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2
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Smith PA. Neuropathic pain; what we know and what we should do about it. FRONTIERS IN PAIN RESEARCH 2023; 4:1220034. [PMID: 37810432 PMCID: PMC10559888 DOI: 10.3389/fpain.2023.1220034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 09/05/2023] [Indexed: 10/10/2023] Open
Abstract
Neuropathic pain can result from injury to, or disease of the nervous system. It is notoriously difficult to treat. Peripheral nerve injury promotes Schwann cell activation and invasion of immunocompetent cells into the site of injury, spinal cord and higher sensory structures such as thalamus and cingulate and sensory cortices. Various cytokines, chemokines, growth factors, monoamines and neuropeptides effect two-way signalling between neurons, glia and immune cells. This promotes sustained hyperexcitability and spontaneous activity in primary afferents that is crucial for onset and persistence of pain as well as misprocessing of sensory information in the spinal cord and supraspinal structures. Much of the current understanding of pain aetiology and identification of drug targets derives from studies of the consequences of peripheral nerve injury in rodent models. Although a vast amount of information has been forthcoming, the translation of this information into the clinical arena has been minimal. Few, if any, major therapeutic approaches have appeared since the mid 1990's. This may reflect failure to recognise differences in pain processing in males vs. females, differences in cellular responses to different types of injury and differences in pain processing in humans vs. animals. Basic science and clinical approaches which seek to bridge this knowledge gap include better assessment of pain in animal models, use of pain models which better emulate human disease, and stratification of human pain phenotypes according to quantitative assessment of signs and symptoms of disease. This can lead to more personalized and effective treatments for individual patients. Significance statement: There is an urgent need to find new treatments for neuropathic pain. Although classical animal models have revealed essential features of pain aetiology such as peripheral and central sensitization and some of the molecular and cellular mechanisms involved, they do not adequately model the multiplicity of disease states or injuries that may bring forth neuropathic pain in the clinic. This review seeks to integrate information from the multiplicity of disciplines that seek to understand neuropathic pain; including immunology, cell biology, electrophysiology and biophysics, anatomy, cell biology, neurology, molecular biology, pharmacology and behavioral science. Beyond this, it underlines ongoing refinements in basic science and clinical practice that will engender improved approaches to pain management.
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Affiliation(s)
- Peter A. Smith
- Neuroscience and Mental Health Institute and Department of Pharmacology, University of Alberta, Edmonton, AB, Canada
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3
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Jiang Y, Zhu Z, Wang B, Yuan Y, Zhang Q, Li Y, Du Y, Gong P. Neuronal TRPV1-CGRP axis regulates bone defect repair through Hippo signaling pathway. Cell Signal 2023:110779. [PMID: 37336315 DOI: 10.1016/j.cellsig.2023.110779] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Revised: 06/13/2023] [Accepted: 06/16/2023] [Indexed: 06/21/2023]
Abstract
Transient receptor potential vanilloid type 1 (TRPV1) is highly expressed on sensory neurons where it serves as a polymodal receptor for detecting physical and chemical stimuli. However, the role of TRPV1 in bone metabolism remains largely unclear. This study aimed to investigate the underlying mechanism of neuronal TRPV1 in regulating bone defect repair. In vivo experiment verified that TRPV1 activation could trigger dorsal root ganglion (DRG) producing the neuropeptide calcitonin gene-related peptide (CGRP) in mice. The accelerated bone healing of femoral defect in this process was observed compared to the control group (p < 0.05). Conversely, Trpv1 knockdown led to the reduced CGRP expression in DRG and nerves innervating femur bone tissue, following impaired bone formation and osteogenic capability in the defect region (p < 0.05), which could be rescued by local CGRP treatment. In vitro, results revealed that TRPV1 function in DRG neurons contributed essentially to the regulation of osteoblast physiology through affecting the production and secretion of CGRP. The capsaicin-activated neuronal TRPV1-CGRP axis could enhance the proliferation, migration and differentiation of osteoblasts (p < 0.05). Furthermore, we found that the promoting role of neuronal TRPV1 in osteogenesis were associated with Hippo signaling pathway, reflected by the phosphorylation protein level of large tumor suppressor 1 (LATS1), MOB kinase activator 1 (MOB1) and Yes-associated protein (YAP), as well as the subcellular location of YAP. Our study clarified the effects and intrinsic mechanisms of neuronal TRPV1 on bone defect repair, which might offer us a therapeutic implication for bone disorders.
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Affiliation(s)
- Yixuan Jiang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China; Department of Oral Implantology, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Zhanfeng Zhu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China; Department of Oral Implantology, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Bin Wang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China; Department of Oral Implantology, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Ying Yuan
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Qin Zhang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yanxi Li
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yu Du
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China; Department of Oral Implantology, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Ping Gong
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China; Department of Oral Implantology, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
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4
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Nieto-Rostro M, Patel R, Dickenson AH, Dolphin AC. Nerve injury increases native Ca V 2.2 trafficking in dorsal root ganglion mechanoreceptors. Pain 2023; 164:1264-1279. [PMID: 36524581 PMCID: PMC10184561 DOI: 10.1097/j.pain.0000000000002846] [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: 10/04/2022] [Revised: 11/16/2022] [Accepted: 11/23/2022] [Indexed: 12/23/2022]
Abstract
ABSTRACT Neuronal N-type (Ca V 2.2) voltage-gated calcium channels are essential for neurotransmission from primary afferent terminals in the dorsal horn. In this study, we have used a knockin mouse containing Ca V 2.2 with an inserted extracellular hemagglutinin tag (Ca V 2.2_HA), to visualise the pattern of expression of endogenous Ca V 2.2 in dorsal root ganglion (DRG) neurons and their primary afferents in the dorsal horn. We examined the effect of partial sciatic nerve ligation (PSNL) and found an increase in Ca V 2.2_HA only in large and medium dorsal root ganglion neurons and also in deep dorsal horn synaptic terminals. Furthermore, there is a parallel increase in coexpression with GFRα1, present in a population of low threshold mechanoreceptors, both in large DRG neurons and in their terminals. The increased expression of Ca V 2.2_HA in these DRG neurons and their terminals is dependent on the presence of the auxiliary subunit α 2 δ-1, which is required for channel trafficking to the cell surface and to synaptic terminals, and it likely contributes to enhanced synaptic transmission at these synapses following PSNL. By contrast, the increase in GFRα1 is not altered in α 2 δ-1-knockout mice. We also found that following PSNL, there is patchy loss of glomerular synapses immunoreactive for Ca V 2.2_HA and CGRP or IB4, restricted to the superficial layers of the dorsal horn. This reduction is not dependent on α 2 δ-1 and likely reflects partial deafferentation of C-nociceptor presynaptic terminals. Therefore, in this pain model, we can distinguish 2 different events affecting specific DRG terminals, with opposite consequences for Ca V 2.2_HA expression and function in the dorsal horn.
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Affiliation(s)
- Manuela Nieto-Rostro
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Ryan Patel
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Anthony H. Dickenson
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Annette C. Dolphin
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
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5
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Rubio MA, Herrando-Grabulosa M, Gaja-Capdevila N, Vilches JJ, Navarro X. Characterization of somatosensory neuron involvement in the SOD1 G93A mouse model. Sci Rep 2022; 12:7600. [PMID: 35534694 PMCID: PMC9085861 DOI: 10.1038/s41598-022-11767-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 04/14/2022] [Indexed: 11/09/2022] Open
Abstract
SOD1G93A mice show loss of cutaneous small fibers, as in ALS patients. Our objective is to characterize the involvement of different somatosensory neuron populations and its temporal progression in the SOD1G93A mice. We aim to further define peripheral sensory involvement, analyzing at the same time points the neuronal bodies located in the dorsal root ganglia (DRG) and the distal part of their axons in the skin, in order to shed light in the mechanisms of sensory involvement in ALS. We performed immunohistochemical analysis of peptidergic (CGRP), non-peptidergic (IB4) fibers in epidermis, as well as sympathetic sudomotor fibers (VIP) in the footpads of SOD1G93A mice and wild type littermates at 4, 8, 12 and 16 weeks of age. We also immunolabeled and quantified neuronal bodies of IB4, CGRP and parvalbumin (PV) positive sensory neurons in lumbar DRG. We detected a reduction of intraepidermal nerve fiber density in the SOD1G93A mice of both peptidergic and non-peptidergic axons, compared with the WT, being the non-peptidergic the fewest. Sweat gland innervation was similarly affected in the SOD1G93A mouse at 12 weeks. Nonetheless, the number of DRG neurons from different sensory populations remained unchanged during all stages. Cutaneous sensory axons are affected in the SOD1G93A mouse, with non-peptidergic being slightly more vulnerable than peptidergic axons. Loss or lack of growth of the distal portion of sensory axons with preservation of the corresponding neuronal bodies suggest a distal axonopathy.
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Affiliation(s)
- Miguel A Rubio
- Neuromuscular Unit, Department of Neurology, Hospital del Mar, Barcelona, Spain.,Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences and CIBERNED, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Mireia Herrando-Grabulosa
- Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences and CIBERNED, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Nuria Gaja-Capdevila
- Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences and CIBERNED, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Jorge J Vilches
- Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences and CIBERNED, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Xavier Navarro
- Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences and CIBERNED, Universitat Autònoma de Barcelona, Bellaterra, Spain. .,Unitat de Fisiologia Medica, Facultat de Medicina, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain.
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6
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Boakye PA, Tang SJ, Smith PA. Mediators of Neuropathic Pain; Focus on Spinal Microglia, CSF-1, BDNF, CCL21, TNF-α, Wnt Ligands, and Interleukin 1β. FRONTIERS IN PAIN RESEARCH 2022; 2:698157. [PMID: 35295524 PMCID: PMC8915739 DOI: 10.3389/fpain.2021.698157] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 07/14/2021] [Indexed: 01/04/2023] Open
Abstract
Intractable neuropathic pain is a frequent consequence of nerve injury or disease. When peripheral nerves are injured, damaged axons undergo Wallerian degeneration. Schwann cells, mast cells, fibroblasts, keratinocytes and epithelial cells are activated leading to the generation of an “inflammatory soup” containing cytokines, chemokines and growth factors. These primary mediators sensitize sensory nerve endings, attract macrophages, neutrophils and lymphocytes, alter gene expression, promote post-translational modification of proteins, and alter ion channel function in primary afferent neurons. This leads to increased excitability and spontaneous activity and the generation of secondary mediators including colony stimulating factor 1 (CSF-1), chemokine C-C motif ligand 21 (CCL-21), Wnt3a, and Wnt5a. Release of these mediators from primary afferent neurons alters the properties of spinal microglial cells causing them to release tertiary mediators, in many situations via ATP-dependent mechanisms. Tertiary mediators such as BDNF, tumor necrosis factor α (TNF-α), interleukin 1β (IL-1β), and other Wnt ligands facilitate the generation and transmission of nociceptive information by increasing excitatory glutamatergic transmission and attenuating inhibitory GABA and glycinergic transmission in the spinal dorsal horn. This review focusses on activation of microglia by secondary mediators, release of tertiary mediators from microglia and a description of their actions in the spinal dorsal horn. Attention is drawn to the substantial differences in the precise roles of various mediators in males compared to females. At least 25 different mediators have been identified but the similarity of their actions at sensory nerve endings, in the dorsal root ganglia and in the spinal cord means there is considerable redundancy in the available mechanisms. Despite this, behavioral studies show that interruption of the actions of any single mediator can relieve signs of pain in experimental animals. We draw attention this paradox. It is difficult to explain how inactivation of one mediator can relieve pain when so many parallel pathways are available.
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Affiliation(s)
- Paul A Boakye
- Department of Anesthesiology, Renaissance School of Medicine, Stony Brook University, Stony Brook, NY, United States
| | - Shao-Jun Tang
- Department of Anesthesiology, Renaissance School of Medicine, Stony Brook University, Stony Brook, NY, United States
| | - Peter A Smith
- Neuroscience and Mental Health Institute and Department of Pharmacology, University of Alberta, Edmonton, AB, Canada
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7
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Wang X, Gou X, Yu X, Bai D, Tan B, Cao P, Qian M, Zheng X, Wang H, Tang P, Zhang C, Ye F, Ni J. Antinociceptive and Antipruritic Effects of HSK21542, a Peripherally-Restricted Kappa Opioid Receptor Agonist, in Animal Models of Pain and Itch. Front Pharmacol 2021; 12:773204. [PMID: 34867403 PMCID: PMC8635029 DOI: 10.3389/fphar.2021.773204] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 10/28/2021] [Indexed: 11/13/2022] Open
Abstract
Kappa opioid receptor (KOR) agonists have been promising therapeutic candidates, owing to their potential for relieving pain and treating intractable pruritus. Although lacking morphine-like central nervous system (CNS) effects, KOR agonists do elicit sedation, dysphoria and diuresis which seriously impede their development. Peripherally-restricted KOR agonists have a poor ability to penetrate into the CNS system, so that CNS-related adverse effects can be ameliorated or even abolished. However, the only approved peripherally-restricted KOR agonist CR845 remains some frequent CNS adverse events. In the present study, we aim to address pharmacological profiles of HSK21542, with an expectation to provide a safe and effective alternative for patients who are suffering from pain and pruritus. The in vitro experimental results showed that HSK21542 was a selective and potent KOR agonist with higher potency than CR845, and had a brain/plasma concentration ratio of 0.001, indicating its peripheral selectivity. In animal models of pain, HSK21542 significantly inhibited acetic acid-, hindpaw incision- or chronic constriction injury-induced pain-related behaviors, and the efficacy was comparable to CR845 at 15 min post-dosing. HSK21542 had a long-lasting analgesic potency with a median effective dose of 1.48 mg/kg at 24 h post-drug in writhing test. Meanwhile, the antinociceptive activity of HSK21542 was effectively reversed by a KOR antagonist nor-binaltorphimine. In addition, HSK21542 had powerful antipruritic activities in compound 48/80-induced itch model. On the other hand, HSK21542 had a weak ability to produce central antinociceptive effects in a hot-plate test and fewer effects on the locomotor activity of mice. HSK21542 didn't affect the respiratory rate of mice. Therefore, HSK21542 might be a safe and effective KOR agonist and promising candidate for treating pain and pruritus.
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Affiliation(s)
- Xin Wang
- Intensive Care Unit, First Affiliated Hospital of Xinjiang Medical University, Urumqi, China
| | - Xiaoli Gou
- Center for Drug Research and Development, Haisco Pharmaceutical Group Co., Ltd., Chegdu, China
| | - Xiaojuan Yu
- Center for Drug Research and Development, Haisco Pharmaceutical Group Co., Ltd., Chegdu, China
| | - Dongdong Bai
- Center for Drug Research and Development, Haisco Pharmaceutical Group Co., Ltd., Chegdu, China
| | - Bowei Tan
- Center for Drug Research and Development, Haisco Pharmaceutical Group Co., Ltd., Chegdu, China
| | - Pingfeng Cao
- Center for Drug Research and Development, Haisco Pharmaceutical Group Co., Ltd., Chegdu, China
| | - Meilin Qian
- Center for Drug Research and Development, Haisco Pharmaceutical Group Co., Ltd., Chegdu, China
| | - Xiaoxiao Zheng
- Center for Drug Research and Development, Haisco Pharmaceutical Group Co., Ltd., Chegdu, China
| | - Hairong Wang
- Center for Drug Research and Development, Haisco Pharmaceutical Group Co., Ltd., Chegdu, China
| | - Pingming Tang
- Center for Drug Research and Development, Haisco Pharmaceutical Group Co., Ltd., Chegdu, China
| | - Chen Zhang
- Center for Drug Research and Development, Haisco Pharmaceutical Group Co., Ltd., Chegdu, China
| | - Fei Ye
- Center for Drug Research and Development, Haisco Pharmaceutical Group Co., Ltd., Chegdu, China
| | - Jia Ni
- Center for Drug Research and Development, Haisco Pharmaceutical Group Co., Ltd., Chegdu, China
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8
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Middleton SJ, Perez-Sanchez J, Dawes JM. The structure of sensory afferent compartments in health and disease. J Anat 2021; 241:1186-1210. [PMID: 34528255 PMCID: PMC9558153 DOI: 10.1111/joa.13544] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 08/12/2021] [Accepted: 08/30/2021] [Indexed: 12/20/2022] Open
Abstract
Primary sensory neurons are a heterogeneous population of cells able to respond to both innocuous and noxious stimuli. Like most neurons they are highly compartmentalised, allowing them to detect, convey and transfer sensory information. These compartments include specialised sensory endings in the skin, the nodes of Ranvier in myelinated axons, the cell soma and their central terminals in the spinal cord. In this review, we will highlight the importance of these compartments to primary afferent function, describe how these structures are compromised following nerve damage and how this relates to neuropathic pain.
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Affiliation(s)
- Steven J Middleton
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | | | - John M Dawes
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
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9
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Gou X, Yu X, Bai D, Tan B, Cao P, Qian M, Zheng X, Chen L, Shi Z, Li Y, Ye F, Liang Y, Ni J. Pharmacology and Mechanism of Action of HSK16149, a Selective Ligand of α2 δ Subunit of Voltage-Gated Calcium Channel with Analgesic Activity in Animal Models of Chronic Pain. J Pharmacol Exp Ther 2020; 376:330-337. [PMID: 33293377 DOI: 10.1124/jpet.120.000315] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 12/04/2020] [Indexed: 02/06/2023] Open
Abstract
Chronic pain is a public health problem because current treatments are unsatisfactory with small therapeutic index. Although pregabalin is effective for treating chronic pain, the clinical use is limited because of its side effects. Therefore, improving its therapeutic index is essential. In this study, HSK16149 was found to be a novel ligand of voltage-gated calcium channel (VGCC) α 2 δ subunit. HSK16149 inhibited [3H]gabapentin binding to the α 2 δ subunit and was 23 times more potent than pregabalin. In two rat models of neuropathic pain, the minimum effective dose (MED) of HSK16149 was 10 mg/kg, and the efficacy was similar to that of 30 mg/kg pregabalin. Moreover, the efficacy of HSK16149 could persist up to 24 hours postadministration at 30 mg/kg, whereas the efficacy of pregabalin lasted only for 12 hours at 30 mg/kg in streptozotocin-induced diabetic neuropathy model, indicating that HSK16149 might be a longer-acting drug candidate. HSK16149 could also inhibit mechanical allodynia in intermittent cold stress model and decrease phase II pain behaviors in formalin-induced nociception model. In addition, the locomotor activity test showed that the MED of HSK16149 was similar to that of pregabalin, whereas in the Rotarod test, the MEDs of HSK16149 and pregabalin were 100 and 30 mg/kg, respectively. These findings indicated that HSK16149 might have a better safety profile on the central nervous system. In summary, HSK16149 is a potent ligand of VGCC α 2 δ subunit with a better therapeutic index than pregabalin. Hence, it could be an effective and safe drug candidate for treating chronic pain. SIGNIFICANCE STATEMENT: As a novel potent ligand of voltage-gated calcium channel α 2 δ subunit, HSK16149 has the potential to be an effective and safe drug candidate for the treatment of chronic pain.
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Affiliation(s)
- Xiaoli Gou
- Haisco Pharmaceutical Group Co., Ltd., Chengdu, China
| | - Xiaojuan Yu
- Haisco Pharmaceutical Group Co., Ltd., Chengdu, China
| | - Dongdong Bai
- Haisco Pharmaceutical Group Co., Ltd., Chengdu, China
| | - Bowei Tan
- Haisco Pharmaceutical Group Co., Ltd., Chengdu, China
| | - Pingfeng Cao
- Haisco Pharmaceutical Group Co., Ltd., Chengdu, China
| | - Meilin Qian
- Haisco Pharmaceutical Group Co., Ltd., Chengdu, China
| | | | - Lei Chen
- Haisco Pharmaceutical Group Co., Ltd., Chengdu, China
| | - Zongjun Shi
- Haisco Pharmaceutical Group Co., Ltd., Chengdu, China
| | - Yao Li
- Haisco Pharmaceutical Group Co., Ltd., Chengdu, China
| | - Fei Ye
- Haisco Pharmaceutical Group Co., Ltd., Chengdu, China
| | - Yong Liang
- Haisco Pharmaceutical Group Co., Ltd., Chengdu, China
| | - Jia Ni
- Haisco Pharmaceutical Group Co., Ltd., Chengdu, China
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10
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Boyle KA, Gradwell MA, Yasaka T, Dickie AC, Polgár E, Ganley RP, Orr DPH, Watanabe M, Abraira VE, Kuehn ED, Zimmerman AL, Ginty DD, Callister RJ, Graham BA, Hughes DI. Defining a Spinal Microcircuit that Gates Myelinated Afferent Input: Implications for Tactile Allodynia. Cell Rep 2020; 28:526-540.e6. [PMID: 31291586 PMCID: PMC6635381 DOI: 10.1016/j.celrep.2019.06.040] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 03/29/2019] [Accepted: 06/10/2019] [Indexed: 12/16/2022] Open
Abstract
Chronic pain presents a major unmet clinical problem. The development of more effective treatments is hindered by our limited understanding of the neuronal circuits underlying sensory perception. Here, we show that parvalbumin (PV)-expressing dorsal horn interneurons modulate the passage of sensory information conveyed by low-threshold mechanoreceptors (LTMRs) directly via presynaptic inhibition and also gate the polysynaptic relay of LTMR input to pain circuits by inhibiting lamina II excitatory interneurons whose axons project into lamina I. We show changes in the functional properties of these PV interneurons following peripheral nerve injury and that silencing these cells unmasks a circuit that allows innocuous touch inputs to activate pain circuits by increasing network activity in laminae I-IV. Such changes are likely to result in the development of tactile allodynia and could be targeted for more effective treatment of mechanical pain.
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Affiliation(s)
- Kieran A Boyle
- Spinal Cord Research Group, Institute of Neuroscience and Psychology, University of Glasgow, Glasgow G12 8QQ, UK
| | - Mark A Gradwell
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Newcastle NSW 2308, Australia
| | - Toshiharu Yasaka
- Department of Anatomy and Physiology, Saga University, Saga 849-8501, Japan
| | - Allen C Dickie
- Spinal Cord Research Group, Institute of Neuroscience and Psychology, University of Glasgow, Glasgow G12 8QQ, UK
| | - Erika Polgár
- Spinal Cord Research Group, Institute of Neuroscience and Psychology, University of Glasgow, Glasgow G12 8QQ, UK
| | - Robert P Ganley
- Spinal Cord Research Group, Institute of Neuroscience and Psychology, University of Glasgow, Glasgow G12 8QQ, UK
| | - Desmond P H Orr
- Spinal Cord Research Group, Institute of Neuroscience and Psychology, University of Glasgow, Glasgow G12 8QQ, UK
| | - Masahiko Watanabe
- Department of Anatomy, Hokkaido University School of Medicine, Sapporo 060-8638, Japan
| | - Victoria E Abraira
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Emily D Kuehn
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Amanda L Zimmerman
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA
| | - David D Ginty
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Robert J Callister
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Newcastle NSW 2308, Australia
| | - Brett A Graham
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Newcastle NSW 2308, Australia.
| | - David I Hughes
- Spinal Cord Research Group, Institute of Neuroscience and Psychology, University of Glasgow, Glasgow G12 8QQ, UK.
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11
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Dong W, Jin SC, Allocco A, Zeng X, Sheth AH, Panchagnula S, Castonguay A, Lorenzo LÉ, Islam B, Brindle G, Bachand K, Hu J, Sularz A, Gaillard J, Choi J, Dunbar A, Nelson-Williams C, Kiziltug E, Furey CG, Conine S, Duy PQ, Kundishora AJ, Loring E, Li B, Lu Q, Zhou G, Liu W, Li X, Sierant MC, Mane S, Castaldi C, López-Giráldez F, Knight JR, Sekula RF, Simard JM, Eskandar EN, Gottschalk C, Moliterno J, Günel M, Gerrard JL, Dib-Hajj S, Waxman SG, Barker FG, Alper SL, Chahine M, Haider S, De Koninck Y, Lifton RP, Kahle KT. Exome Sequencing Implicates Impaired GABA Signaling and Neuronal Ion Transport in Trigeminal Neuralgia. iScience 2020; 23:101552. [PMID: 33083721 PMCID: PMC7554653 DOI: 10.1016/j.isci.2020.101552] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 09/06/2020] [Accepted: 09/08/2020] [Indexed: 02/07/2023] Open
Abstract
Trigeminal neuralgia (TN) is a common, debilitating neuropathic face pain syndrome often resistant to therapy. The familial clustering of TN cases suggests that genetic factors play a role in disease pathogenesis. However, no unbiased, large-scale genomic study of TN has been performed to date. Analysis of 290 whole exome-sequenced TN probands, including 20 multiplex kindreds and 70 parent-offspring trios, revealed enrichment of rare, damaging variants in GABA receptor-binding genes in cases. Mice engineered with a TN-associated de novo mutation (p.Cys188Trp) in the GABAA receptor Cl− channel γ-1 subunit (GABRG1) exhibited trigeminal mechanical allodynia and face pain behavior. Other TN probands harbored rare damaging variants in Na+ and Ca+ channels, including a significant variant burden in the α-1H subunit of the voltage-gated Ca2+ channel Cav3.2 (CACNA1H). These results provide exome-level insight into TN and implicate genetically encoded impairment of GABA signaling and neuronal ion transport in TN pathogenesis. Genomic analysis of trigeminal neuralgia (TN) using exome sequencing Rare mutations in GABA signaling and ion transport genes are enriched in TN cases Generation of a genetic TN mouse model engineered with a patient-specific mutation
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Affiliation(s)
- Weilai Dong
- Department of Genetics, Yale School of Medicine, New Haven, CT, USA.,Laboratory of Human Genetics and Genomics, The Rockefeller University, New York, NY, USA
| | - Sheng Chih Jin
- Department of Genetics, Washington University School of Medicine, St. Louis, MO, USA
| | - August Allocco
- Department of Neurosurgery, Yale School of Medicine, New Haven, CT, USA
| | - Xue Zeng
- Department of Genetics, Yale School of Medicine, New Haven, CT, USA.,Laboratory of Human Genetics and Genomics, The Rockefeller University, New York, NY, USA
| | - Amar H Sheth
- Department of Neurosurgery, Yale School of Medicine, New Haven, CT, USA
| | | | - Annie Castonguay
- CERVO Brain Research Centre, Université Laval, Québec, QC, Canada
| | | | - Barira Islam
- University College London, School of Pharmacy, London, England
| | | | - Karine Bachand
- CERVO Brain Research Centre, Université Laval, Québec, QC, Canada
| | - Jamie Hu
- Department of Neurosurgery, Yale School of Medicine, New Haven, CT, USA
| | - Agata Sularz
- Department of Neurosurgery, Yale School of Medicine, New Haven, CT, USA
| | - Jonathan Gaillard
- Department of Neurosurgery, Yale School of Medicine, New Haven, CT, USA
| | - Jungmin Choi
- Department of Genetics, Yale School of Medicine, New Haven, CT, USA.,Laboratory of Human Genetics and Genomics, The Rockefeller University, New York, NY, USA.,Department of Biomedical Sciences, Korea University College of Medicine, 02841 Seoul, Korea
| | - Ashley Dunbar
- Department of Neurosurgery, Yale School of Medicine, New Haven, CT, USA
| | | | - Emre Kiziltug
- Department of Neurosurgery, Yale School of Medicine, New Haven, CT, USA
| | | | - Sierra Conine
- Department of Neurosurgery, Yale School of Medicine, New Haven, CT, USA
| | - Phan Q Duy
- Department of Neurosurgery, Yale School of Medicine, New Haven, CT, USA
| | - Adam J Kundishora
- Department of Neurosurgery, Yale School of Medicine, New Haven, CT, USA
| | - Erin Loring
- Department of Genetics, Yale School of Medicine, New Haven, CT, USA
| | - Boyang Li
- Department of Biostatistics, Yale School of Public Health, New Haven, CT, USA
| | - Qiongshi Lu
- Department of Biostatistics & Medical Informatics, University of Wisconsin-Madison, Madison, WI, USA
| | - Geyu Zhou
- Program of Computational Biology and Bioinformatics, Yale University, New Haven, CT, USA
| | - Wei Liu
- Program of Computational Biology and Bioinformatics, Yale University, New Haven, CT, USA
| | - Xinyue Li
- School of Data Science, City University of Hong Kong, Hong Kong, China
| | - Michael C Sierant
- Department of Genetics, Yale School of Medicine, New Haven, CT, USA.,Laboratory of Human Genetics and Genomics, The Rockefeller University, New York, NY, USA
| | - Shrikant Mane
- Yale Center for Genome Analysis, West Haven, CT, USA
| | | | | | | | - Raymond F Sekula
- Department of Neurological Surgery, University of Pittsburgh School of Medicine and University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - J Marc Simard
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Emad N Eskandar
- Department of Neurological Surgery, Albert Einstein College of Medicine, Montefiore Medical Center, New York
| | | | | | - Murat Günel
- Department of Neurosurgery, Yale School of Medicine, New Haven, CT, USA
| | - Jason L Gerrard
- Department of Neurosurgery, Yale School of Medicine, New Haven, CT, USA
| | - Sulayman Dib-Hajj
- Center for Neuroscience & Regeneration Research, VA Connecticut Healthcare System, West Haven, CT, USA.,Department of Neurology; Yale University, New Haven, CT, USA
| | - Stephen G Waxman
- Center for Neuroscience & Regeneration Research, VA Connecticut Healthcare System, West Haven, CT, USA.,Department of Neurology; Yale University, New Haven, CT, USA
| | - Fred G Barker
- Harvard Medical School, Boston, MA, USA.,Cancer Center, Massachusetts General Hospital, Boston, MA, USA.,Department of Neurosurgery, Massachusetts General Hospital, Boston, MA, USA
| | - Seth L Alper
- Division of Nephrology and Center for Vascular Biology Research, Beth Israel Deaconess Medical Center, and Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Mohamed Chahine
- CERVO Brain Research Centre, Université Laval, Québec, QC, Canada.,Department of Medicine, Université Laval, Québec, QC, Canada
| | - Shozeb Haider
- University College London, School of Pharmacy, London, England
| | - Yves De Koninck
- CERVO Brain Research Centre, Université Laval, Québec, QC, Canada.,Department of Psychiatry and Neuroscience, Université Laval, Québec, QC, Canada
| | - Richard P Lifton
- Department of Genetics, Yale School of Medicine, New Haven, CT, USA.,Laboratory of Human Genetics and Genomics, The Rockefeller University, New York, NY, USA
| | - Kristopher T Kahle
- Department of Neurosurgery, Yale School of Medicine, New Haven, CT, USA.,Department of Pediatrics, Yale School of Medicine, New Haven, CT, USA.,Department of Cellular & Molecular Physiology, Yale School of Medicine, New Haven, CT, USA
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12
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Neurochemical and Ultrastructural Characterization of Unmyelinated Non-peptidergic C-Nociceptors and C-Low Threshold Mechanoreceptors Projecting to Lamina II of the Mouse Spinal Cord. Cell Mol Neurobiol 2020; 41:247-262. [PMID: 32306148 DOI: 10.1007/s10571-020-00847-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 04/09/2020] [Indexed: 12/19/2022]
Abstract
C-nociceptors (C-Ncs) and non-nociceptive C-low threshold mechanoreceptors (C-LTMRs) are two subpopulations of small unmyelinated non-peptidergic C-type neurons of the dorsal root ganglia (DRGs) with central projections displaying a specific pattern of termination in the spinal cord dorsal horn. Although these two subpopulations exist in several animals, remarkable neurochemical differences occur between mammals, particularly rat/humans from one side and mouse from the other. Mouse is widely investigated by transcriptomics. Therefore, we here studied the immunocytochemistry of murine C-type DRG neurons and their central terminals in spinal lamina II at light and electron microscopic levels. We used a panel of markers for peptidergic (CGRP), non-peptidergic (IB4), nociceptive (TRPV1), non-nociceptive (VGLUT3) C-type neurons and two strains of transgenic mice: the TAFA4Venus knock-in mouse to localize the TAFA4+ C-LTMRs, and a genetically engineered ginip mouse that allows an inducible and tissue-specific ablation of the DRG neurons expressing GINIP, a key modulator of GABABR-mediated analgesia. We confirmed that IB4 and TAFA4 did not coexist in small non-peptidergic C-type DRG neurons and separately tagged the C-Ncs and the C-LTMRs. We then showed that TRPV1 was expressed in only about 7% of the IB4+ non-peptidergic C-Ncs and their type Ia glomerular terminals within lamina II. Notably, the selective ablation of GINIP did not affect these neurons, whereas it reduced IB4 labeling in the medial part of lamina II and the density of C-LTMRs glomerular terminals to about one half throughout the entire lamina. We discuss the significance of these findings for interspecies differences and functional relevance.
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13
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Crawford LK, Caterina MJ. Functional Anatomy of the Sensory Nervous System: Updates From the Neuroscience Bench. Toxicol Pathol 2019; 48:174-189. [PMID: 31554486 DOI: 10.1177/0192623319869011] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The simple tripartite classification of sensory neurons as A-beta, A-delta, and C fibers fails to convey the complexity of the neurons that encode stimuli as diverse as the texture of a surface, the location of a pinprick, or the direction of hair movement as a breeze moves across the skin. It has also proven to be inadequate when investigating the molecular mechanisms underlying pain, which can encompass any combination of chemical, tactile, and thermal modalities. Beginning with a brief overview of visceral and sensory neuroanatomy, this review expands upon sensory innervation of the skin as a prime example of the heterogeneity and complexity of the somatosensory nervous system. Neuroscientists have characterized defining features of over 15 subtypes of sensory neurons that innervate the skin of the mouse. This has enabled the study of cell-specific mechanisms of pain, which suggests that diverse sensory neuron subtypes may have distinct susceptibilities to toxic injury and different roles in pathologic mechanisms underlying altered sensation. Leveraging this growing body of knowledge for preclinical trials and models of neurotoxicity can vastly improve our understanding of peripheral nervous system dysfunction, advancing the fields of toxicologic pathology and neuropathology alike.
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Affiliation(s)
- LaTasha K Crawford
- Department of Pathobiological Sciences, University of Wisconsin-Madison School of Veterinary Medicine, Madison, WI, USA, Madison, WI, USA
| | - Michael J Caterina
- Neurosurgery Pain Research Institute, Johns Hopkins School of Medicine, Baltimore, MD, USA
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14
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Increased Expression of Fibronectin Leucine-Rich Transmembrane Protein 3 in the Dorsal Root Ganglion Induces Neuropathic Pain in Rats. J Neurosci 2019; 39:7615-7627. [PMID: 31346030 DOI: 10.1523/jneurosci.0295-19.2019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 05/17/2019] [Accepted: 06/06/2019] [Indexed: 01/19/2023] Open
Abstract
Neuropathic pain is a chronic condition that occurs frequently after nerve injury and induces hypersensitivity or allodynia characterized by aberrant neuronal excitability in the spinal cord dorsal horn. Fibronectin leucine-rich transmembrane protein 3 (FLRT3) is a modulator of neurite outgrowth, axon pathfinding, and cell adhesion, which is upregulated in the dorsal horn following peripheral nerve injury. However, the function of FLRT3 in adults remains unknown. Therefore, we aimed to investigate the involvement of spinal FLRT3 in neuropathic pain using rodent models. In the dorsal horns of male rats, FLRT3 protein levels increased at day 4 after peripheral nerve injury. In the DRG, FLRT3 was expressed in activating transcription factor 3-positive, injured sensory neurons. Peripheral nerve injury stimulated Flrt3 transcription in the DRG but not in the spinal cord. Intrathecal administration of FLRT3 protein to naive rats induced mechanical allodynia and GluN2B phosphorylation in the spinal cord. DRG-specific FLRT3 overexpression using adeno-associated virus also produced mechanical allodynia. Conversely, a function-blocking FLRT3 antibody attenuated mechanical allodynia after partial sciatic nerve ligation. Therefore, FLRT3 derived from injured DRG neurons increases dorsal horn excitability and induces mechanical allodynia.SIGNIFICANCE STATEMENT Neuropathic pain occurs frequently after nerve injury and is associated with abnormal neuronal excitability in the spinal cord. Fibronectin leucine-rich transmembrane protein 3 (FLRT3) regulates neurite outgrowth and cell adhesion. Here, nerve injury increased FLRT3 protein levels in the spinal cord dorsal root, despite the fact that Flrt3 transcripts were only induced in the DRG. FLRT3 protein injection into the rat spinal cord induced mechanical hypersensitivity, as did virus-mediated FLRT3 overexpression in DRG. Conversely, FLRT3 inhibition with antibodies attenuated mechanically induced pain after nerve damage. These findings suggest that FLRT3 is produced by injured DRG neurons and increases neuronal excitability in the dorsal horn, leading to pain sensitization. Neuropathic pain induction is a novel function of FLRT3.
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15
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Noh MC, Stemkowski PL, Smith PA. Long-term actions of interleukin-1β on K +, Na + and Ca 2+ channel currents in small, IB 4-positive dorsal root ganglion neurons; possible relevance to the etiology of neuropathic pain. J Neuroimmunol 2019; 332:198-211. [PMID: 31077855 DOI: 10.1016/j.jneuroim.2019.05.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 04/18/2019] [Accepted: 05/01/2019] [Indexed: 12/25/2022]
Abstract
Excitation of dorsal root ganglion (DRG) neurons by interleukin 1β (IL-1β) is implicated in the onset of neuropathic pain. To understand its mechanism of action, isolectin B4 positive (IB4+) DRG neurons were exposed to 100pM IL-1β for 5-6d. A reversible increase in action potential (AP) amplitude reflected increased TTX-sensitive sodium current (TTX-S INa). An irreversible increase in AP duration reflected decreased Ca2+- sensitive K+ conductance (BK(Ca) channels). Different processes thus underlie regulation of the two channel types. Since changes in AP shape facilitated Ca2+ influx, this explains how IL-1β facilitates synaptic transmission in the dorsal horn; thereby provoking pain.
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Affiliation(s)
- Myung-Chul Noh
- Department of Pharmacology, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Patrick L Stemkowski
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Peter A Smith
- Department of Pharmacology, University of Alberta, Edmonton, Alberta T6G 2H7, Canada; Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta T6G 2H7, Canada.
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16
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Yu H, Shin SM, Wang F, Xu H, Xiang H, Cai Y, Itson-Zoske B, Hogan QH. Transmembrane protein 100 is expressed in neurons and glia of dorsal root ganglia and is reduced after painful nerve injury. Pain Rep 2018; 4:e703. [PMID: 30801043 PMCID: PMC6370145 DOI: 10.1097/pr9.0000000000000703] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 10/08/2018] [Accepted: 10/30/2018] [Indexed: 12/16/2022] Open
Abstract
Introduction Tmem100 modulates interactions between TRPA1 and TRPV1. The cell specificity of Tmem100 expression in dorsal root ganglia (DRGs) is not well defined, nor is the effect of peripheral nerve injury on Tmem100 expression. Objective This study was designed to determine the cell specificity of Tmem100 expression in DRG and its subcellular localization, and to examine how Tmem100 expression may be altered in painful conditions. Methods Dorsal root ganglion Tmem100 expression was determined by immunohistochemistry, immunoblot, and quantitative real-time PCR, and compared between various experimental rat pain models and controls. Results Tmem100 is expressed in both neurons and perineuronal glial cells in the rat DRG. The plasma membrane and intracellular localization of Tmem100 are identified in 83% ± 6% of IB4-positive and 48% ± 6% of calcitonin gene-related peptide-positive neurons, as well as in medium- and large-sized neurons, with its immunopositivity colocalized to TRPV1 (94% ± 5%) and TRPA1 (96% ± 3%). Tmem100 is also detected in the perineuronal satellite glial cells and in some microglia. Tmem100 protein is significantly increased in the lumbar DRGs in the complete Freund adjuvant inflammatory pain. By contrast, peripheral nerve injury by spinal nerve ligation diminishes Tmem100 expression in the injured DRG, with immunoblot and immunohistochemistry experiments showing reduced Tmem100 protein levels in both neurons and satellite glial cells of DRGs proximal to injury, whereas Tmem100 is unchanged in adjacent DRGs. The spared nerve injury model also reduces Tmem100 protein in the injured DRGs. Conclusion Our data demonstrate a pain pathology-dependent alteration of DRG Tmem100 protein expression, upregulated during CFA inflammatory pain but downregulated during neuropathic pain.
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Affiliation(s)
- Hongwei Yu
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Zablocki Veterans Affairs Medical Center, Milwaukee, WI, USA
| | - Seung Min Shin
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Fei Wang
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Medical Experiment Center, Shaanxi University of Chinese Medicine, Xianyang, Shaanxi, PR of China
| | - Hao Xu
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Department of Orthopedic Surgery, Affiliated Hospital of Qingdao University, Qingdao, PR of China
| | - Hongfei Xiang
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Department of Orthopedic Surgery, Affiliated Hospital of Qingdao University, Qingdao, PR of China
| | - Yongsong Cai
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, PR of China
| | - Brandon Itson-Zoske
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Quinn H Hogan
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Zablocki Veterans Affairs Medical Center, Milwaukee, WI, USA
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17
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Inyang KE, Szabo-Pardi T, Wentworth E, McDougal TA, Dussor G, Burton MD, Price TJ. The antidiabetic drug metformin prevents and reverses neuropathic pain and spinal cord microglial activation in male but not female mice. Pharmacol Res 2018; 139:1-16. [PMID: 30391353 DOI: 10.1016/j.phrs.2018.10.027] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 10/16/2018] [Accepted: 10/28/2018] [Indexed: 12/25/2022]
Abstract
Metformin is a widely prescribed drug used in the treatment of type II diabetes. While the drug has many mechanisms of action, most of these converge on AMP activated protein kinase (AMPK), which metformin activates. AMPK is a multifunctional kinase that is a negative regulator of mechanistic target of rapamycin (mTOR) and mitogen activated protein kinase (MAPK) signaling. Activation of AMPK decreases the excitability of dorsal root ganglion neurons and AMPK activators are effective in reducing chronic pain in inflammatory, post-surgical and neuropathic rodent models. We have previously shown that metformin leads to an enduring resolution of neuropathic pain in the spared nerve injury (SNI) model in male mice and rats. The precise mechanism underlying this long-lasting effect is not known. We conducted experiments to investigate the effects of metformin on SNI-induced microglial activation, a process implicated in the maintenance of neuropathic pain that has recently been shown to be sexually dimorphic. We find that metformin is effective at inhibiting development of neuropathic pain when treatment is given around the time of injury and that metformin is likewise effective at reversing neuropathic mechanical hypersensitivity when treatment is initiation weeks after injury. This effect is linked to decreased Iba-1 staining in the dorsal horn, a marker of microglial activation. Importantly, these positive behavioral and microglia effects of metformin were only observed in male mice. We conclude that the neuropathic pain modifying effects of metformin are sex-specific supporting a differential role for microglial activation in male and female mice.
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Affiliation(s)
- Kufreobong E Inyang
- School of Behavioral and Brain Sciences and Center for Advanced Pain Studies, University of Texas at Dallas, United States
| | - Thomas Szabo-Pardi
- School of Behavioral and Brain Sciences and Center for Advanced Pain Studies, University of Texas at Dallas, United States
| | - Emma Wentworth
- School of Behavioral and Brain Sciences and Center for Advanced Pain Studies, University of Texas at Dallas, United States
| | - Timothy A McDougal
- School of Behavioral and Brain Sciences and Center for Advanced Pain Studies, University of Texas at Dallas, United States
| | - Gregory Dussor
- School of Behavioral and Brain Sciences and Center for Advanced Pain Studies, University of Texas at Dallas, United States
| | - Michael D Burton
- School of Behavioral and Brain Sciences and Center for Advanced Pain Studies, University of Texas at Dallas, United States.
| | - Theodore J Price
- School of Behavioral and Brain Sciences and Center for Advanced Pain Studies, University of Texas at Dallas, United States.
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18
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Involvement of advillin in somatosensory neuron subtype-specific axon regeneration and neuropathic pain. Proc Natl Acad Sci U S A 2018; 115:E8557-E8566. [PMID: 30126982 PMCID: PMC6130359 DOI: 10.1073/pnas.1716470115] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
An estimated 20 million people in the United States have chronic neuropathic pain, but current analgesics are nonspecific or insufficiently effective. Here we show that advillin, a sensory neuron-specific protein, modulates axonal regeneration of a specific subset of pain-sensing afferent neurons (nociceptors) that binds with isolectin B4 and neuropathic pain. In addition, we identify the cell behavior of advillin shed-off from the growth cone in the context of axonal regeneration and thus detected advillin protein in the cerebrospinal fluid in mice with painful peripheral neuropathy. Advillin is a potential biosignature to diagnose the lesion cause of neuropathic pain associated with isolectin B4+ nociceptors. Advillin is a sensory neuron-specific actin-binding protein expressed at high levels in all types of somatosensory neurons in early development. However, the precise role of advillin in adulthood is largely unknown. Here we reveal advillin expression restricted to isolectin B4-positive (IB4+) neurons in the adult dorsal root ganglia (DRG). Advillin knockout (KO) specifically impaired axonal regeneration in adult IB4+ DRG neurons. During axon regeneration, advillin was expressed at the very tips of filopodia and modulated growth cone formation by interacting with and regulating focal-adhesion–related proteins. The advillin-containing focal-adhesion protein complex was shed from neurite tips during neurite retraction and was detectable in cerebrospinal fluid in experimental autoimmune encephalomyelitis, oxaliplatin-induced peripheral neuropathy, and chronic constriction injury of the sciatic nerve. In addition, advillin KO disturbed experimental autoimmune encephalomyelitis-induced neural plasticity in the spinal-cord dorsal horn and aggravated neuropathic pain. Our study highlights a role for advillin in growth cone formation, axon regeneration, and neuropathic pain associated with IB4+ DRG neurons in adulthood.
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20
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Zou Y, Xu F, Tang Z, Zhong T, Cao J, Guo Q, Huang C. Distinct calcitonin gene-related peptide expression pattern in primary afferents contribute to different neuropathic symptoms following chronic constriction or crush injuries to the rat sciatic nerve. Mol Pain 2018; 12:1744806916681566. [PMID: 28256957 PMCID: PMC5521344 DOI: 10.1177/1744806916681566] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Although calcitonin gene-related peptide is a recognized pain transducer, the expression of calcitonin gene-related peptide in primary afferents may be differentially affected following different types of nerve injury. Here, we examined whether different calcitonin gene-related peptide expression patterns in primary afferents contributes to distinct sensory disturbances in three animal models of sciatic nerve injury: chronic constriction injury, mild (100g force) or strong (1000g force) transient crush in rats. Assessments of withdrawal reflexes and spontaneous behavior indicated that chronic constriction injury and mild crush resulted in positive neuropathic symptoms (static/dynamic mechanical allodynia, heat hyperalgesia, cold allodynia, spontaneous pain). However, strong crush led to both positive (dynamic mechanical allodynia, cold allodynia, spontaneous pain) and negative symptoms (static mechanical hypoesthesia, heat hypoalgesia). Calcitonin gene-related peptide immunoreactivity in dorsal root ganglia and corresponding spinal cord segments, and calcitonin gene-related peptide mRNA levels in dorsal root ganglia, indicated that the primary afferent calcitonin gene-related peptide supply was markedly reduced only after strong crush. This reduction paralleled the development of negative symptoms (static mechanical hypoesthesia and heat hypoalgesia). Administration of exogenous calcitonin gene-related peptide intrathecally after strong crush did not alter heat hypoalgesia but ameliorated static mechanical hypoesthesia, an effect blocked by a calcitonin gene-related peptide receptor antagonist. Thus, reducing the primary afferent calcitonin gene-related peptide supply contributed to subsequent negative neuropathic symptoms, especially to static mechanical stimuli. Moreover, nerve injury caused a subcellular redistribution of calcitonin gene-related peptide from small- and medium-size dorsal root ganglia neurons to large-size dorsal root ganglia neurons, which paralleled the development of positive neuropathic symptoms. Intrathecal administration of the calcitonin gene-related peptide receptor antagonist ameliorated these positive symptoms, indicating that the expression of calcitonin gene-related peptide in large-size dorsal root ganglia neurons is important for the positive neuropathic symptoms in all three models. Taken together, these results suggest that distinct calcitonin gene-related peptide expression pattern in primary afferents contribute to different neuropathic symptoms following chronic constriction or crush injuries to the rat sciatic nerve.
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Affiliation(s)
- Yu Zou
- 1 Department of Anesthesiology, Xiangya Hospital of Central South University, Changsha, China
| | - Fangting Xu
- 1 Department of Anesthesiology, Xiangya Hospital of Central South University, Changsha, China
| | - Zhaohui Tang
- 1 Department of Anesthesiology, Xiangya Hospital of Central South University, Changsha, China
| | - Tao Zhong
- 1 Department of Anesthesiology, Xiangya Hospital of Central South University, Changsha, China
| | - Jiawei Cao
- 1 Department of Anesthesiology, Xiangya Hospital of Central South University, Changsha, China
| | - Qulian Guo
- 1 Department of Anesthesiology, Xiangya Hospital of Central South University, Changsha, China
| | - Changsheng Huang
- 1 Department of Anesthesiology, Xiangya Hospital of Central South University, Changsha, China
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21
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Wegner KA, Cadena MT, Trevena R, Turco AE, Gottschalk A, Halberg RB, Guo J, McMahon JA, McMahon AP, Vezina CM. An immunohistochemical identification key for cell types in adult mouse prostatic and urethral tissue sections. PLoS One 2017; 12:e0188413. [PMID: 29145476 PMCID: PMC5690684 DOI: 10.1371/journal.pone.0188413] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 11/06/2017] [Indexed: 02/07/2023] Open
Abstract
Though many methods can be used to identify cell types contained in complex tissues, most require cell disaggregation and destroy information about where cells reside in relation to their microenvironment. Here, we describe a polytomous key for cell type identification in intact sections of adult mouse prostate and prostatic urethra. The key is organized as a decision tree and initiates with one round of immunostaining for nerve, epithelial, fibromuscular/hematolymphoid, or vascular associated cells. Cell identities are recursively eliminated by subsequent staining events until the remaining pool of potential cell types can be distinguished by direct comparison to other cells. We validated our identification key using wild type adult mouse prostate and urethra tissue sections and it currently resolves sixteen distinct cell populations which include three nerve fiber types as well as four epithelial, five fibromuscular/hematolymphoid, one nerve-associated, and three vascular-associated cell types. We demonstrate two uses of this novel identification methodology. We first used the identification key to characterize prostate stromal cell type changes in response to constitutive phosphatidylinositide-3-kinase activation in prostate epithelium. We then used the key to map cell lineages in a new reporter mouse strain driven by Wnt10aem1(cre/ERT2)Amc. The identification key facilitates rigorous and reproducible cell identification in prostate tissue sections and can be expanded to resolve additional cell types as new antibodies and other resources become available.
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Affiliation(s)
- Kyle A. Wegner
- George M. O’Brien Benign Urology Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Molecular and Environmental Toxicology Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Mark T. Cadena
- George M. O’Brien Benign Urology Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Ryan Trevena
- George M. O’Brien Benign Urology Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Anne E. Turco
- George M. O’Brien Benign Urology Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Molecular and Environmental Toxicology Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Adam Gottschalk
- School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Richard B. Halberg
- Department of Oncology, McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Jinjin Guo
- Department of Stem Cell Biology and Regenerative Medicine, Eli and Edythe Broad-CIRM Center for Regenerative Medicine and Stem Cell Research, W.M. Keck School of Medicine of the University of Southern California, Los Angeles, CA, United States of America
| | - Jill A. McMahon
- Department of Stem Cell Biology and Regenerative Medicine, Eli and Edythe Broad-CIRM Center for Regenerative Medicine and Stem Cell Research, W.M. Keck School of Medicine of the University of Southern California, Los Angeles, CA, United States of America
| | - Andrew P. McMahon
- Department of Stem Cell Biology and Regenerative Medicine, Eli and Edythe Broad-CIRM Center for Regenerative Medicine and Stem Cell Research, W.M. Keck School of Medicine of the University of Southern California, Los Angeles, CA, United States of America
| | - Chad M. Vezina
- George M. O’Brien Benign Urology Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Molecular and Environmental Toxicology Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Carbone Cancer Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- * E-mail:
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22
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Roza C, Mazo I, Rivera-Arconada I, Cisneros E, Alayón I, López-García JA. Analysis of spontaneous activity of superficial dorsal horn neurons in vitro: neuropathy-induced changes. Pflugers Arch 2016; 468:2017-2030. [PMID: 27726011 DOI: 10.1007/s00424-016-1886-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 09/06/2016] [Accepted: 09/26/2016] [Indexed: 01/17/2023]
Abstract
The superficial dorsal horn contains large numbers of interneurons which process afferent and descending information to generate the spinal nociceptive message. Here, we set out to evaluate whether adjustments in patterns and/or temporal correlation of spontaneous discharges of these neurons are involved in the generation of central sensitization caused by peripheral nerve damage. Multielectrode arrays were used to record from discrete groups of such neurons in slices from control or nerve damaged mice. Whole-cell recordings of individual neurons were also obtained. A large proportion of neurons recorded extracellularly showed well-defined patterns of spontaneous firing. Clock-like neurons (CL) showed regular discharges at ∼6 Hz and represented 9 % of the sample in control animals. They showed a tonic-firing pattern to direct current injection and depolarized membrane potentials. Irregular fast-burst neurons (IFB) produced short-lasting high-frequency bursts (2-5 spikes at ∼100 Hz) at irregular intervals and represented 25 % of the sample. They showed bursting behavior upon direct current injection. Of the pairs of neurons recorded, 10 % showed correlated firing. Correlated pairs always included an IFB neuron. After nerve damage, the mean spontaneous firing frequency was unchanged, but the proportion of CL increased significantly (18 %) and many of these neurons appeared to acquire a novel low-threshold A-fiber input. Similarly, the percentage of IFB neurons was unaltered, but synchronous firing was increased to 22 % of the pairs studied. These changes may contribute to transform spinal processing of nociceptive inputs following peripheral nerve damage. The specific roles that these neurons may play are discussed.
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Affiliation(s)
- Carolina Roza
- Dpto. Biología de Sistemas, Edificio de Medicina, Universidad de Alcalá, Campus Universitario, 28871, Alcalá de Henares, Madrid, Spain
| | - Irene Mazo
- Dpto. Biología de Sistemas, Edificio de Medicina, Universidad de Alcalá, Campus Universitario, 28871, Alcalá de Henares, Madrid, Spain
| | - Iván Rivera-Arconada
- Dpto. Biología de Sistemas, Edificio de Medicina, Universidad de Alcalá, Campus Universitario, 28871, Alcalá de Henares, Madrid, Spain
| | - Elsa Cisneros
- Dpto. Biología de Sistemas, Edificio de Medicina, Universidad de Alcalá, Campus Universitario, 28871, Alcalá de Henares, Madrid, Spain
| | - Ismel Alayón
- Dpto. Biología de Sistemas, Edificio de Medicina, Universidad de Alcalá, Campus Universitario, 28871, Alcalá de Henares, Madrid, Spain
| | - José A López-García
- Dpto. Biología de Sistemas, Edificio de Medicina, Universidad de Alcalá, Campus Universitario, 28871, Alcalá de Henares, Madrid, Spain.
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23
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Seltzman HH, Shiner C, Hirt EE, Gilliam AF, Thomas BF, Maitra R, Snyder R, Black SL, Patel PR, Mulpuri Y, Spigelman I. Peripherally Selective Cannabinoid 1 Receptor (CB1R) Agonists for the Treatment of Neuropathic Pain. J Med Chem 2016; 59:7525-43. [PMID: 27482723 DOI: 10.1021/acs.jmedchem.6b00516] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Alleviation of neuropathic pain by cannabinoids is limited by their central nervous system (CNS) side effects. Indole and indene compounds were engineered for high hCB1R affinity, peripheral selectivity, metabolic stability, and in vivo efficacy. An epithelial cell line assay identified candidates with <1% blood-brain barrier penetration for testing in a rat neuropathy induced by unilateral sciatic nerve entrapment (SNE). The SNE-induced mechanical allodynia was reversibly suppressed, partially or completely, after intraperitoneal or oral administration of several indenes. At doses that relieve neuropathy symptoms, the indenes completely lacked, while the brain-permeant CB1R agonist HU-210 (1) exhibited strong CNS side effects, in catalepsy, hypothermia, and motor incoordination assays. Pharmacokinetic findings of ∼0.001 cerebrospinal fluid:plasma ratio further supported limited CNS penetration. Pretreatment with selective CB1R or CB2R blockers suggested mainly CB1R contribution to an indene's antiallodynic effects. Therefore, this class of CB1R agonists holds promise as a viable treatment for neuropathic pain.
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Affiliation(s)
- Herbert H Seltzman
- Center for Drug Discovery, Research Triangle Institute , Research Triangle Park, North Carolina 27709, United States
| | - Craig Shiner
- Center for Drug Discovery, Research Triangle Institute , Research Triangle Park, North Carolina 27709, United States
| | - Erin E Hirt
- Center for Drug Discovery, Research Triangle Institute , Research Triangle Park, North Carolina 27709, United States
| | - Anne F Gilliam
- Center for Drug Discovery, Research Triangle Institute , Research Triangle Park, North Carolina 27709, United States
| | - Brian F Thomas
- Center for Drug Discovery, Research Triangle Institute , Research Triangle Park, North Carolina 27709, United States
| | - Rangan Maitra
- Center for Drug Discovery, Research Triangle Institute , Research Triangle Park, North Carolina 27709, United States
| | - Rod Snyder
- Center for Drug Discovery, Research Triangle Institute , Research Triangle Park, North Carolina 27709, United States
| | - Sherry L Black
- Center for Drug Discovery, Research Triangle Institute , Research Triangle Park, North Carolina 27709, United States
| | - Purvi R Patel
- Center for Drug Discovery, Research Triangle Institute , Research Triangle Park, North Carolina 27709, United States
| | - Yatendra Mulpuri
- Division of Oral Biology & Medicine, School of Dentistry, University of California , 10833 Le Conte Avenue, 63-078 CHS, Los Angeles, California 090095-1668, United States
| | - Igor Spigelman
- Division of Oral Biology & Medicine, School of Dentistry, University of California , 10833 Le Conte Avenue, 63-078 CHS, Los Angeles, California 090095-1668, United States
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24
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Liu Z, Wang F, Fischer G, Hogan QH, Yu H. Peripheral nerve injury induces loss of nociceptive neuron-specific Gαi-interacting protein in neuropathic pain rat. Mol Pain 2016; 12:12/0/1744806916646380. [PMID: 27145804 PMCID: PMC4956147 DOI: 10.1177/1744806916646380] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 03/16/2016] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Gαi-interacting protein (GINIP) is expressed specifically in dorsal root ganglion (DRG) neurons and functions in modulation of peripheral gamma-aminobutyric acid B receptor (GBR). Genetic deletion of GINIP leads to impaired responsiveness to GBR agonist-mediated analgesia in rodent. It is, however, not defined whether nerve injury changes GINIP expression. RESULTS Immunolabeling with validated antibody revealed GINIP expression in ~40% of total lumbar DRG neurons in normal adult rats. GINIP immunoreactivity was detected in ~80% of IB4-positive (nonpeptidergic) and ~30% of CGRP-positive (peptidergic) neurons. GINIP immunoreactivity in the spinal cord dorsal horn was colabeled with IB4 and partially with CGRP. In addition, GINIP was expressed in DRG neurons immunopositive for GBR1, GBR2, Gαi(s), and Gαo and was also extensively colabeled with multiple nociceptive neuronal markers, including Trpv1, NaV1.7, CaV2.2α1b, CaV3.2α1b, TrkA, and Trek2. Peripheral nerve injury by L5 spinal nerve ligation significantly decreased the proportion of GINIP immunoreactivity-positive neurons from 40 ± 8.4% to 0.8 ± 0.1% (p < 0.01, mean ± SD, four weeks after spinal nerve ligation) and the total GINIP protein to 1.3% ± 0.04% of its basal level (p < 0.01, n = 6 animals in each group, two weeks after spinal nerve ligation) in the ipsilateral L5 DRGs. CONCLUSION Our results show that GINIP is predominantly expressed by small nonpeptidergic nociceptive neurons and that nerve injury triggers loss of GINIP expression. Signal transduction roles of GINIP may be diverse as it colabeled with various subgroups of nociceptive neurons. Future studies may investigate details of the signaling mechanism engaged by GINIP, as well as the pathophysiological significance of lost expression of GINIP in neuropathic pain.
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Affiliation(s)
- Zhen Liu
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA Department of General Surgery, West China Hospital, Sichuan University, Chengdu, Sichuan, PR China
| | - Fei Wang
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA Department of Physiology, Shaanxi University of Chinese Medicine, Xianyang, Shaanxi, PR China
| | - Gregory Fischer
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Quinn H Hogan
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA Zablocki Veterans Affairs Medical Center, Milwaukee, WI, USA
| | - Hongwei Yu
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA Zablocki Veterans Affairs Medical Center, Milwaukee, WI, USA
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25
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Saeed AW, Pawlowski SA, Ribeiro-da-Silva A. Limited changes in spinal lamina I dorsal horn neurons following the cytotoxic ablation of non-peptidergic C-fibers. Mol Pain 2015; 11:54. [PMID: 26353788 PMCID: PMC4564961 DOI: 10.1186/s12990-015-0060-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 08/31/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Non-peptidergic nociceptive neurons are a sub-population of small diameter primary sensory neurons that comprise approximately 50 % of the C fiber population. Together with the peptidergic sub-population, they transmit nociceptive information from the periphery to the superficial dorsal horn of the spinal cord. Despite the numerous studies investigating the role of the non-peptidergic primary afferents, their role in normal nociception and in pain remains poorly understood. Our lab has previously demonstrated that, in rat models of neuropathic and inflammatory pain, there is a de novo expression of substance P receptors (NK-1r) by lamina I pyramidal projection neurons, a neuronal population that normally does not express these receptors. RESULTS In this study, we used a ribosomal toxin, saporin, conjugated to the lectin IB4 to selectively ablate the non-peptidergic nociceptive C fibers, to investigate if the loss of these fibers was enough to induce a change in NK-1r expression by lamina I projection neurons. IB4-saporin treatment led to the permanent ablation of the IB4-positive afferents but also to a small non-significant reduction in CGRP-positive afferents. An overall increase in immunoreactivity for the NK-1r was observed in lamina I projection neurons, however, the lack of non-peptidergic afferents did not increase the number of lamina I pyramidal projection neurons immunoreactive for the receptor. CONCLUSIONS Our results demonstrate that the deletion of the non-peptidergic afferents, at the L4-L5 spinal levels, is not sufficient to trigger the de novo expression of NK-1r by projection pyramidal neurons but increases the expression of NK-1r in fusiform and multipolar projection neurons. Furthermore, our data suggest that a neuropathic component is essential to trigger the expression of NK-1r by pyramidal neurons.
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Affiliation(s)
- Abeer W Saeed
- Department of Pharmacology and Therapeutics, McGill University, 3655 Promenade Sir-William-Osler, Montreal, QC, H3G 1Y6, Canada. .,Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, H3A 0G1, Canada.
| | - Sophie A Pawlowski
- Department of Pharmacology and Therapeutics, McGill University, 3655 Promenade Sir-William-Osler, Montreal, QC, H3G 1Y6, Canada. .,Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, H3A 0G1, Canada.
| | - Alfredo Ribeiro-da-Silva
- Department of Pharmacology and Therapeutics, McGill University, 3655 Promenade Sir-William-Osler, Montreal, QC, H3G 1Y6, Canada. .,Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, H3A 0G1, Canada. .,Department of Anatomy and Cell Biology, McGill University, Montreal, QC, H3A 0C7, Canada.
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26
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Oyamaguchi A, Abe T, Sugiyo S, Niwa H, Takemura M. Selective elimination of isolectin B4-binding trigeminal neurons enhanced formalin-induced nocifensive behavior in the upper lip of rats and c-Fos expression in the trigeminal subnucleus caudalis. Neurosci Res 2015. [PMID: 26216055 DOI: 10.1016/j.neures.2015.07.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The functional significance of non-peptidergic C-fibers in orofacial pain processing is largely unknown. The present study examined the effects of the selective elimination of isolectin B4 (IB4)-binding (IB4(+)) neurons on formalin-induced face rubbing behavior (FRB) in the upper lip of rats and c-Fos-immunoreactive (c-Fos-IR) cells in the trigeminal subnucleus caudalis (Vc). IB4 conjugated to neurotoxin, saporin (IB4-Sap), blank-saporin (Bl-Sap), or saline (Sal) was injected into the cisterna magna. IB4-Sap treatments significantly decreased IB4(+) terminals in lamina II of Vc and IB4(+) trigeminal ganglia neurons, whereas Sal- and BI-Sap treatments did not. The number of formalin-induced FRB 15-30 min after the formalin injection was significantly higher in IB4-Sap-treated rats than in Sal- or Bl-Sap-treated rats, and was associated with an increase in c-Fos-IR cells. The systemic preadministration of the GABAA antagonist, bicuculline, and agonist, muscimol, had stronger decreasing effects on FRB and c-Fos-IR cells in IB4-Sap-treated rats than the preadministration of Sal, whereas the opposite effects were observed in Sal- and Bl-Sap-treated rats. These results indicate that IB4(+) neurons in the trigeminal nerve play antinociceptive regulatory roles in formalin-induced orofacial pain processing and that GABAA receptor functions at segmental and supratrigeminal sites have complex modulatory influences on antinociceptive roles.
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Affiliation(s)
- Aiko Oyamaguchi
- Department of Dental Anesthesiology, Osaka University Graduate School of Dentistry, Japan.
| | - Tetsuya Abe
- Department of Dentistry and Oral Surgery, Hyogo College of Medicine, Japan.
| | - Shinichi Sugiyo
- Department of Acupuncture, Takarazuka University of Medical and Health Care, Japan.
| | - Hitoshi Niwa
- Department of Dental Anesthesiology, Osaka University Graduate School of Dentistry, Japan.
| | - Motohide Takemura
- Department of Oral Anatomy, Osaka University Graduate School of Dentistry, Japan.
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27
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Park J, Trinh VN, Sears-Kraxberger I, Li KW, Steward O, Luo ZD. Synaptic ultrastructure changes in trigeminocervical complex posttrigeminal nerve injury. J Comp Neurol 2015; 524:309-22. [PMID: 26132987 DOI: 10.1002/cne.23844] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Revised: 06/23/2015] [Accepted: 06/25/2015] [Indexed: 12/20/2022]
Abstract
Trigeminal nerves collecting sensory information from the orofacial area synapse on second-order neurons in the dorsal horn of subnucleus caudalis and cervical C1/C2 spinal cord (Vc/C2, or trigeminocervical complex), which is critical for sensory information processing. Injury to the trigeminal nerves may cause maladaptive changes in synaptic connectivity that plays an important role in chronic pain development. Here we examined whether injury to the infraorbital nerve, a branch of the trigeminal nerves, led to synaptic ultrastructural changes when the injured animals have developed neuropathic pain states. Transmission electron microscopy was used to examine synaptic profiles in Vc/C2 at 3 weeks postinjury, corresponding to the time of peak behavioral hypersensitivity following chronic constriction injury to the infraorbital nerve (CCI-ION). Using established criteria, synaptic profiles were classified as associated with excitatory (R-), inhibitory (F-), and primary afferent (C-) terminals. Each type was counted within the superficial dorsal horn of the Vc/C2 and the means from each rat were compared between sham and injured animals; synaptic contact length was also measured. The overall analysis indicates that rats with orofacial pain states had increased numbers and decreased mean synaptic length of R-profiles within the Vc/C2 superficial dorsal horn (lamina I) 3 weeks post-CCI-ION. Increases in the number of excitatory synapses in the superficial dorsal horn of Vc/C2 could lead to enhanced activation of nociceptive pathways, contributing to the development of orofacial pain states.
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Affiliation(s)
- John Park
- Department of Pharmacology, University of California Irvine, School of Medicine, Irvine, California, 92697
| | - Van Nancy Trinh
- Department of Anesthesiology & Perioperative Care, University of California Irvine, School of Medicine, Irvine, California, 92697
| | - Ilse Sears-Kraxberger
- Reeve-Irvine Research Center, University of California Irvine, School of Medicine, Irvine, California, 92697
| | - Kang-Wu Li
- Department of Anesthesiology & Perioperative Care, University of California Irvine, School of Medicine, Irvine, California, 92697
| | - Oswald Steward
- Reeve-Irvine Research Center, University of California Irvine, School of Medicine, Irvine, California, 92697
| | - Z David Luo
- Department of Pharmacology, University of California Irvine, School of Medicine, Irvine, California, 92697.,Department of Anesthesiology & Perioperative Care, University of California Irvine, School of Medicine, Irvine, California, 92697.,Reeve-Irvine Research Center, University of California Irvine, School of Medicine, Irvine, California, 92697
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28
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Effects of active immunisation with myelin basic protein and myelin-derived altered peptide ligand on pain hypersensitivity and neuroinflammation. J Neuroimmunol 2015; 286:59-70. [PMID: 26298325 DOI: 10.1016/j.jneuroim.2015.07.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 06/23/2015] [Accepted: 07/09/2015] [Indexed: 12/21/2022]
Abstract
Neuropathic pain is a debilitating condition in multiple sclerosis and experimental autoimmune encephalomyelitis (EAE). Specific myelin basic protein (MBP) peptides are encephalitogenic, and myelin-derived altered peptide ligands (APLs) are capable of preventing and ameliorating EAE. We investigated the effects of active immunisation with a weakly encephalitogenic epitope of MBP (MBP87-99) and its mutant APL (Cyclo-87-99[A(91),A(96)]MBP87-99) on pain hypersensitivity and neuroinflammation in Lewis rats. MBP-treated rats exhibited significant mechanical and thermal pain hypersensitivity associated with infiltration of T cells, MHC class II expression and microglia activation in the spinal cord, without developing clinical signs of paralysis. Co-immunisation with APL significantly decreased pain hypersensitivity and neuroinflammation emphasising the important role of neuroimmune crosstalk in neuropathic pain.
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29
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Presynaptic modulation of spinal nociceptive transmission by glial cell line-derived neurotrophic factor (GDNF). J Neurosci 2015; 34:13819-33. [PMID: 25297108 DOI: 10.1523/jneurosci.0808-14.2014] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The role of glial cell line-derived neurotrophic factor (GDNF) in nociceptive pathways is still controversial, as both pronociceptive and antinociceptive actions have been reported. To elucidate this role in the mouse, we performed combined structural and functional studies in vivo and in acute spinal cord slices where C-fiber activation was mimicked by capsaicin challenge. Nociceptors and their terminals in superficial dorsal horn (SDH; laminae I-II) constitute two separate subpopulations: the peptidergic CGRP/somatostatin+ cells expressing GDNF and the nonpeptidergic IB4+ neurons expressing the GFRα1-RET GDNF receptor complex. Ultrastructurally the dorsal part of inner lamina II (LIIid) harbors a mix of glomeruli that either display GDNF/somatostatin (GIb)-IR or GFRα1/IB4 labeling (GIa). LIIid thus represents the preferential site for ligand-receptor interactions. Functionally, endogenous GDNF released from peptidergic CGRP/somatostatin+ nociceptors upon capsaicin stimulation exert a tonic inhibitory control on the glutamate excitatory drive of SDH neurons as measured after ERK1/2 phosphorylation assay. Real-time Ca(2+) imaging and patch-clamp experiments with bath-applied GDNF (100 nM) confirm the presynaptic inhibition of SDH neurons after stimulation of capsaicin-sensitive, nociceptive primary afferent fibers. Accordingly, the reduction of the capsaicin-evoked [Ca(2+)]i rise and of the frequency of mEPSCs in SDH neurons is specifically abolished after enzymatic ablation of GFRα1. Therefore, GDNF released from peptidergic CGRP/somatostatin+ nociceptors acutely depresses neuronal transmission in SDH signaling to nonpeptidergic IB4+ nociceptors at glomeruli in LIIid. These observations are of potential pharmacological interest as they highlight a novel modality of cross talk between nociceptors that may be relevant for discrimination of pain modalities.
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30
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Casals-Díaz L, Casas C, Navarro X. Changes of voltage-gated sodium channels in sensory nerve regeneration and neuropathic pain models. Restor Neurol Neurosci 2015; 33:321-34. [DOI: 10.3233/rnn-140444] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Laura Casals-Díaz
- Group of Neuroplasticity and Regeneration, Institute of Neurosciences and Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Bellaterra, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Spain
| | - Caty Casas
- Group of Neuroplasticity and Regeneration, Institute of Neurosciences and Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Bellaterra, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Spain
| | - Xavier Navarro
- Group of Neuroplasticity and Regeneration, Institute of Neurosciences and Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Bellaterra, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Spain
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31
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Murakami K, Tanaka T, Bando Y, Yoshida S. Nerve injury induces the expression of syndecan-1 heparan sulfate proteoglycan in primary sensory neurons. Neuroscience 2015; 300:338-50. [PMID: 26002314 DOI: 10.1016/j.neuroscience.2015.05.033] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 04/26/2015] [Accepted: 05/13/2015] [Indexed: 12/18/2022]
Abstract
Heparan sulfate proteoglycans (HSPGs) have important functions in development of the central nervous system; however, their functions in nerve injury are not yet fully understood. We previously reported the expression of syndecan-1, a type of HSPG, in cranial motor neurons after nerve injury, suggesting the importance of syndecan-1 in the pathology of motor nerve injury. In this study, we examined the expression of syndecan-1, a type of HSPG, in primary sensory neurons after nerve injury in mice. Sciatic nerve axotomy strongly induced the expression of syndecan-1 in a subpopulation of injured dorsal root ganglion (DRG) neurons, which were small in size and had CGRP- or isolectin B4-positive fibers. Syndecan-1 was also distributed in the dorsal horn of the spinal cord ipsilateral to the axotomy, and located on the membrane of axons in lamina II of the dorsal horn. Not only sciatic nerve axotomy, infraorbital nerve axotomy also induced the expression of syndecan-1 in trigeminal ganglion neurons. Moreover, syndecan-1 knockdown in cultured DRG neurons induced a shorter neurite extension. These results suggest that syndecan-1 expression in injured primary sensory neurons may have functional roles in nerve regeneration and synaptic plasticity, resulting in the development of neuropathic pain.
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Affiliation(s)
- K Murakami
- Department of Functional Anatomy and Neuroscience, Asahikawa Medical University, Japan.
| | - T Tanaka
- Department of Functional Anatomy and Neuroscience, Asahikawa Medical University, Japan
| | - Y Bando
- Department of Functional Anatomy and Neuroscience, Asahikawa Medical University, Japan
| | - S Yoshida
- Department of Functional Anatomy and Neuroscience, Asahikawa Medical University, Japan
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32
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Forrest SL, Payne SC, Keast JR, Osborne PB. Peripheral injury of pelvic visceral sensory nerves alters GFRα (GDNF family receptor alpha) localization in sensory and autonomic pathways of the sacral spinal cord. Front Neuroanat 2015; 9:43. [PMID: 25914629 PMCID: PMC4392586 DOI: 10.3389/fnana.2015.00043] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 03/19/2015] [Indexed: 02/04/2023] Open
Abstract
GDNF (glial cell line-derived neurotrophic factor), neurturin and artemin use their co-receptors (GFRα1, GFRα2 and GFRα3, respectively) and the tyrosine kinase Ret for downstream signaling. In rodent dorsal root ganglia (DRG) most of the unmyelinated and some myelinated sensory afferents express at least one GFRα. The adult function of these receptors is not completely elucidated but their activity after peripheral nerve injury can facilitate peripheral and central axonal regeneration, recovery of sensation, and sensory hypersensitivity that contributes to pain. Our previous immunohistochemical studies of spinal cord and sciatic nerve injuries in adult rodents have identified characteristic changes in GFRα1, GFRα2 or GFRα3 in central spinal cord axons of sensory neurons located in DRG. Here we extend and contrast this analysis by studying injuries of the pelvic and hypogastric nerves that contain the majority of sensory axons projecting to the pelvic viscera (e.g., bladder and lower bowel). At 7 d, we detected some effects of pelvic but not hypogastric nerve transection on the ipsilateral spinal cord. In sacral (L6-S1) cord ipsilateral to nerve injury, GFRα1-immunoreactivity (IR) was increased in medial dorsal horn and CGRP-IR was decreased in lateral dorsal horn. Pelvic nerve injury also upregulated GFRα1- and GFRα3-IR terminals and GFRα1-IR neuronal cell bodies in the sacral parasympathetic nucleus that provides the spinal parasympathetic preganglionic output to the pelvic nerve. This evidence suggests peripheral axotomy has different effects on somatic and visceral sensory input to the spinal cord, and identifies sensory-autonomic interactions as a possible site of post-injury regulation.
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Affiliation(s)
- Shelley L Forrest
- Pain Management Research Institute (Kolling Institute), University of Sydney at the Royal North Shore Hospital Sydney, NSW, Australia
| | - Sophie C Payne
- Department of Anatomy and Neuroscience, The University of Melbourne Melbourne, VIC, Australia
| | - Janet R Keast
- Pain Management Research Institute (Kolling Institute), University of Sydney at the Royal North Shore Hospital Sydney, NSW, Australia ; Department of Anatomy and Neuroscience, The University of Melbourne Melbourne, VIC, Australia
| | - Peregrine B Osborne
- Pain Management Research Institute (Kolling Institute), University of Sydney at the Royal North Shore Hospital Sydney, NSW, Australia ; Department of Anatomy and Neuroscience, The University of Melbourne Melbourne, VIC, Australia
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Su J, Gao T, Shi T, Xiang Q, Xu X, Wiesenfeld-Hallin Z, Hökfelt T, Svensson CI. Phenotypic changes in dorsal root ganglion and spinal cord in the collagen antibody-induced arthritis mouse model. J Comp Neurol 2015; 523:1505-28. [DOI: 10.1002/cne.23749] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 12/26/2014] [Accepted: 01/24/2015] [Indexed: 12/31/2022]
Affiliation(s)
- Jie Su
- Department of Physiology and Pharmacology; Karolinska Institutet; Stockholm 171 77 Sweden
| | - Tianle Gao
- Department of Physiology and Pharmacology; Karolinska Institutet; Stockholm 171 77 Sweden
| | - Tiejun Shi
- Department of Neuroscience; Karolinska Institutet; Stockholm 171 77 Sweden
| | - Qiong Xiang
- Department of Neuroscience; Karolinska Institutet; Stockholm 171 77 Sweden
| | - Xiaojun Xu
- Department of Physiology and Pharmacology; Karolinska Institutet; Stockholm 171 77 Sweden
| | | | - Tomas Hökfelt
- Department of Neuroscience; Karolinska Institutet; Stockholm 171 77 Sweden
| | - Camilla I. Svensson
- Department of Physiology and Pharmacology; Karolinska Institutet; Stockholm 171 77 Sweden
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Smith PA. BDNF: No gain without pain? Neuroscience 2014; 283:107-23. [DOI: 10.1016/j.neuroscience.2014.05.044] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 05/16/2014] [Accepted: 05/21/2014] [Indexed: 12/22/2022]
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Biggs JE, Boakye PA, Ganesan N, Stemkowski PL, Lantero A, Ballanyi K, Smith PA. Analysis of the long-term actions of gabapentin and pregabalin in dorsal root ganglia and substantia gelatinosa. J Neurophysiol 2014; 112:2398-412. [DOI: 10.1152/jn.00168.2014] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The α2δ-ligands pregabalin (PGB) and gabapentin (GBP) are used to treat neuropathic pain. We used whole cell recording to study their long-term effects on substantia gelatinosa and dorsal root ganglion (DRG) neurons. Spinal cord slices were prepared from embryonic day 13 rat embryos and maintained in organotypic culture for >5 wk (neuronal age equivalent to young adult rats). Exposure of similarly aged DRG neurons (dissociated and cultured from postnatal day 19 rats) to GBP or PGB for 5–6 days attenuated high-voltage-activated calcium channel currents (HVA ICa). Strong effects were seen in medium-sized and in small isolectin B4-negative (IB4−) DRG neurons, whereas large neurons and small neurons that bound isolectin B4 (IB4+) were hardly affected. GBP (100 μM) or PGB (10 μM) were less effective than 20 μM Mn2+ in suppression of HVA ICa in small DRG neurons. By contrast, 5–6 days of exposure to these α2δ-ligands was more effective than 20 μM Mn2+ in reducing spontaneous excitatory postsynaptic currents at synapses in substantia gelatinosa. Spinal actions of gabapentinoids cannot therefore be ascribed to decreased expression of HVA Ca2+ channels in primary afferent nerve terminals. In substantia gelatinosa, 5–6 days of exposure to PGB was more effective in inhibiting excitatory synaptic drive to putative excitatory neurons than to putative inhibitory neurons. Although spontaneous inhibitory postsynaptic currents were also attenuated, the overall long-term effect of α2δ-ligands was to decrease network excitability as monitored by confocal Ca2+ imaging. We suggest that selective actions of α2δ-ligands on populations of DRG neurons may predict their selective attenuation of excitatory transmission onto excitatory vs. inhibitory neurons in substantia gelatinosa.
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Affiliation(s)
- James E. Biggs
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada; and
| | - Paul A. Boakye
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
| | - Naren Ganesan
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
| | | | - Aquilino Lantero
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada; and
| | - Klaus Ballanyi
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
- Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada
| | - Peter A. Smith
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada; and
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Lorenzo LE, Magnussen C, Bailey AL, St Louis M, De Koninck Y, Ribeiro-da-Silva A. Spatial and temporal pattern of changes in the number of GAD65-immunoreactive inhibitory terminals in the rat superficial dorsal horn following peripheral nerve injury. Mol Pain 2014; 10:57. [PMID: 25189404 PMCID: PMC4164746 DOI: 10.1186/1744-8069-10-57] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Accepted: 08/26/2014] [Indexed: 01/12/2023] Open
Abstract
Inhibitory interneurons are an important component of dorsal horn circuitry where they serve to modulate spinal nociception. There is now considerable evidence indicating that reduced inhibition in the spinal dorsal horn contributes to neuropathic pain. A loss of these inhibitory neurons after nerve injury is one of the mechanisms being proposed to account for reduced inhibition; however, this remains controversial. This is in part because previous studies have focused on global measurements of inhibitory neurons without assessing the number of inhibitory synapses. To address this, we conducted a quantitative analysis of the spatial and temporal changes in the number of inhibitory terminals, as detected by glutamic acid decarboxylase 65 (GAD65) immunoreactivity, in the superficial dorsal horn of the spinal cord following a chronic constriction injury (CCI) to the sciatic nerve in rats. Isolectin B4 (IB4) labelling was used to define the location within the dorsal horn directly affected by the injury to the peripheral nerve. The density of GAD65 inhibitory terminals was reduced in lamina I (LI) and lamina II (LII) of the spinal cord after injury. The loss of GAD65 terminals was greatest in LII with the highest drop occurring around 3–4 weeks and a partial recovery by 56 days. The time course of changes in the number of GAD65 terminals correlated well with both the loss of IB4 labeling and with the altered thresholds to mechanical and thermal stimuli. Our detailed analysis of GAD65+ inhibitory terminals clearly revealed that nerve injury induced a transient loss of GAD65 immunoreactive terminals and suggests a potential involvement for these alterations in the development and amelioration of pain behaviour.
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Affiliation(s)
| | | | | | | | | | - Alfredo Ribeiro-da-Silva
- Department of Pharmacology and Therapeutics, McGill University, 3655 Promenade Sir-William-Osler, Montreal, Quebec H3G 1Y6, Canada.
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Saeed AW, Ribeiro-da-Silva A. De novo expression of neurokinin-1 receptors by spinoparabrachial lamina I pyramidal neurons following a peripheral nerve lesion. J Comp Neurol 2013; 521:1915-28. [PMID: 23172292 DOI: 10.1002/cne.23267] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2012] [Revised: 09/07/2012] [Accepted: 11/09/2012] [Indexed: 01/07/2023]
Abstract
Lamina I of the spinal dorsal horn is a major site of integration and transmission to higher centers of nociceptive information from the periphery. One important primary afferent population that transmits such information to the spinal cord expresses substance P (SP). These fibers terminate in contact with lamina I projection neurons that express the SP receptor, also known as the neurokinin-1 receptor (NK-1r). Three types of lamina I projection neurons have been described: multipolar, fusiform, and pyramidal. Most neurons of the first two types are thought to be nociceptive and express the NK-1r, whereas most pyramidal neurons are nonnociceptive and do not express the NK-1r. In this immunocytochemical and behavioral study, we induced a neuropathic pain-like condition in the rat by means of a polyethylene cuff placed around in the sciatic nerve. We document that this lesion led to a de novo expression of NK-1r on pyramidal neurons as well as a significant increase in SP-immunoreactive innervation onto these neurons. These phenotypic changes were evident at the time of onset of neuropathic pain-related behavior. Additionally, we show that, after a noxious stimulus (intradermal capsaicin injection), these NK-1r on pyramidal neurons were internalized, providing evidence that these neurons become responsive to peripheral noxious stimulation. We suggest that the changes following nerve lesion in the phenotype and innervation pattern of pyramidal neurons are of significance for neuropathic pain and/or limb temperature regulation.
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Affiliation(s)
- Abeer W Saeed
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec H3G 1Y6, Canada
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Peripheral nerve injury produces a sustained shift in the balance between glutamate release and uptake in the dorsal horn of the spinal cord. Pain 2012; 153:2422-2431. [PMID: 23021150 DOI: 10.1016/j.pain.2012.08.011] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Revised: 07/31/2012] [Accepted: 08/22/2012] [Indexed: 12/20/2022]
Abstract
Peripheral nerve injury provokes heightened excitability of primary sensory afferents including nociceptors, and elicits ectopic activity in lesioned and neighboring intact nerve fibers. The major transmitter released by sensory afferents in the superficial dorsal horn of the spinal cord is glutamate. Glutamate is critically involved in nociceptive signaling and the development of neuropathic pain. We recorded miniature excitatory postsynaptic currents (mEPSCs) from neurons in lamina II of the rat dorsal horn to assess spontaneous synaptic activity after spared nerve injury (SNI), a model of chronic neuropathic pain. Following SNI, the frequency of mEPSCs doubled, indicating heightened glutamate release from primary afferents or spinal interneurons. Consistent with this finding, glutamate concentrations in the cerebrospinal fluid were elevated at 1 and 4 weeks after SNI. Transmitter uptake was insufficient to prevent the rise in extracellular glutamate as the expression of glutamate transporters remained unchanged or decreased. 2-Methyl-6-(phenylethynyl)pyridine hydrochloride, an antagonist of metabotropic glutamate receptor 5 (mGluR5), reduced the frequency of mEPSCs to its preinjury level, suggesting a positive feedback mechanism that involves facilitation of transmitter release by mGluR5 activation in the presence of high extracellular glutamate. Treatment with the β-lactam antibiotic ceftriaxone increased the expression of glutamate transporter 1 (Glt1) in the dorsal horn after SNI, raised transmitter uptake, and lowered extracellular glutamate. Improving glutamate clearance prevented the facilitation of transmitter release by mGluR5 and attenuated neuropathic pain-like behavior. Balancing glutamate release and uptake after nerve injury should be an important target in the management of chronic neuropathic pain.
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Vega-Avelaira D, McKelvey R, Hathway G, Fitzgerald M. The emergence of adolescent onset pain hypersensitivity following neonatal nerve injury. Mol Pain 2012; 8:30. [PMID: 22531549 PMCID: PMC3443028 DOI: 10.1186/1744-8069-8-30] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Accepted: 04/24/2012] [Indexed: 12/30/2022] Open
Abstract
Background Peripheral nerve injuries can trigger neuropathic pain in adults but cause little or no pain when they are sustained in infancy or early childhood. This is confirmed in rodent models where neonatal nerve injury causes no pain behaviour. However, delayed pain can arise in man some considerable time after nerve damage and to examine this following early life nerve injury we have carried out a longer term follow up of rat pain behaviour into adolescence and adulthood. Results Spared nerve injury (SNI) or sham surgery was performed on 10 day old (P10) rat pups and mechanical nociceptive reflex thresholds were analysed 3, 7, 14, 21, 28, 38 and 44 days post surgery. While mechanical thresholds on the ipsilateral side are not significantly different from controls for the first 2–3 weeks post P10 surgery, after that time period, beginning at 21 days post surgery (P31), the SNI group developed following early life nerve injury significant hypersensitivity compared to the other groups. Ipsilateral mechanical nociceptive threshold was 2-fold below that of the contralateral and sham thresholds at 21 days post surgery (SNI-ipsilateral 28 (±5) g control groups 69 (±9) g, p < 0.001, 3-way ANOVA, n = 6 per group). Importantly, no effect was observed on thermal thresholds. This hypersensivity was accompanied by macrophage, microglial and astrocyte activation in the DRG and dorsal horn, but no significant change in dorsal horn p38 or JNK expression. Preemptive minocycline (daily 40 mg/kg, s.c) did not prevent the effect. Ketamine (20 mg/kg, s.c), on the other hand, produced a dose-dependent reversal of mechanical nociceptive thresholds ipsilateral to the nerve injury such that thresholds return to control levels at the highest doses of 20 mg/Kg. Conclusions We report a novel consequence of early life nerve injury whereby mechanical hypersensitivity only emerges later in life. This delayed adolescent onset in mechanical pain thresholds is accompanied by neuroimmune activation and NMDA dependent central sensitization of spinal nociceptive circuits. This delayed onset in mechanical pain sensitivity may provide clues to understand the long term effects of early injury such as late onset phantom pain and the emergence of complex adolescent chronic pain syndromes.
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Affiliation(s)
- David Vega-Avelaira
- UCL Department of Neuroscience, Physiology & Pharmacology, University College London, Gower Street, London WC1E6BT, UK.
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Wang D, Chen T, Gao Y, Quirion R, Hong Y. Inhibition of SNL-induced upregulation of CGRP and NPY in the spinal cord and dorsal root ganglia by the 5-HT(2A) receptor antagonist ketanserin in rats. Pharmacol Biochem Behav 2012; 101:379-86. [PMID: 22342663 DOI: 10.1016/j.pbb.2012.02.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 02/01/2012] [Accepted: 02/05/2012] [Indexed: 12/11/2022]
Abstract
Our previous study has demonstrated that topical and systemic administration of the 5-HT(2A) receptor antagonist ketanserin attenuates neuropathic pain. To explore the mechanisms involved, we examined whether ketanserin reversed the plasticity changes associated with calcitonin gene-related peptides (CGRP) and neuropeptide Y (NPY) which may reflect distinct mechanisms: involvement and compensatory protection. Behavioral responses to thermal and tactile stimuli after spinal nerve ligation (SNL) at L5 demonstrated neuropathic pain and its attenuation in the vehicle- and ketanserin-treated groups, respectively. SNL surgery induced an increase in CGRP and NPY immunoreactivity (IR) in laminae I-II of the spinal cord. L5 SNL produced an expression of NPY-IR in large, medium and small diameter neurons in dorsal root ganglion (DRG) only at L5, but not adjacent L4 and L6. Daily injection of ketanserin (0.3 mg/kg, s.c.) for two weeks suppressed the increase in CGRP-IR and NPY-IR in the spinal cord or DRG. The present study demonstrated that: (1) the expression of CGRP was enhanced in the spinal dorsal horn and NPY was expressed in the DRG containing injured neurons, but not in the adjacent DRG containing intact neurons, following L5 SNL; (2) the maladaptive changes in CGRP and NPY expression in the spinal cord and DRG mediated the bioactivity of 5-HT/5-HT(2A) receptors in neuropathic pain and (3) the blockade of 5-HT(2A) receptors by ketanserin reversed the evoked upregulation of both CGRP and NPY in the spinal cord and DRG contributing to the inhibition of neuropathic pain.
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Affiliation(s)
- Dongmei Wang
- Provincial Key Laboratory of Developmental Biology and Neuroscience, College of Life Sciences, Fujian Normal University, Fuzhou, Fujian, 350108, People's Republic of China
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El Maarouf A, Kolesnikov Y, Pasternak G, Rutishauser U. Neural cell adhesion molecule and its polysialic acid moiety exhibit opposing and linked effects on neuropathic hyperalgesia. Exp Neurol 2011; 233:866-70. [PMID: 22200540 DOI: 10.1016/j.expneurol.2011.12.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Revised: 12/05/2011] [Accepted: 12/09/2011] [Indexed: 12/30/2022]
Abstract
Spinal lamina II, where nociceptive C-fibers terminate, expresses high amounts of the polysialylated form of neural cell adhesion molecule (PSA-NCAM). While enzymatic removal of the PSA moiety from NCAM did not affect normal sensitivity to thermal stimuli, it exacerbated nerve injury-induced neuropathic hyperalgesia. The genetic removal of the NCAM core protein also did not alter thermal sensitivity. However in the presence of a peripheral nerve injury, NCAM-null mutants exhibited a complete suppression of thermal hyperalgesia. This strong NCAM mutant phenotype appears to involve the long form of NCAM's cytoplasmic domain, in that it is duplicated by selective genetic deletion of the NCAM-180 isoform. PSA appears therefore to provide a mechanism for modulation of chronic sensory overload, by means of attenuation of the activity of the NCAM-180 isoform, which reduces nociceptive transmission.
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Affiliation(s)
- Abderrahman El Maarouf
- Department of Cell Biology, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021, USA.
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Ruangsri S, Lin A, Mulpuri Y, Lee K, Spigelman I, Nishimura I. Relationship of axonal voltage-gated sodium channel 1.8 (NaV1.8) mRNA accumulation to sciatic nerve injury-induced painful neuropathy in rats. J Biol Chem 2011; 286:39836-47. [PMID: 21965668 PMCID: PMC3220569 DOI: 10.1074/jbc.m111.261701] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Revised: 09/27/2011] [Indexed: 12/21/2022] Open
Abstract
Painful peripheral neuropathy is a significant clinical problem; however, its pathological mechanism and effective treatments remain elusive. Increased peripheral expression of tetrodotoxin-resistant voltage-gated sodium channel 1.8 (NaV1.8) has been shown to associate with chronic pain symptoms in humans and experimental animals. Sciatic nerve entrapment (SNE) injury was used to develop neuropathic pain symptoms in rats, resulting in increased NaV1.8 mRNA in the injured nerve but not in dorsal root ganglia (DRG). To study the role of NaV1.8 mRNA in the pathogenesis of SNE-induced painful neuropathy, NaV1.8 shRNA vector was delivered by subcutaneous injection of cationized gelatin/plasmid DNA polyplex into the rat hindpaw and its subsequent retrograde transport via sciatic nerve to DRG. This in vivo NaV1.8 shRNA treatment reversibly and repeatedly attenuated the SNE-induced pain symptoms, an effect that became apparent following a distinct lag period of 3-4 days and lasted for 4-6 days before returning to pretreatment levels. Surprisingly, apparent knockdown of NaV1.8 mRNA occurred only in the injured nerve, not in the DRG, during the pain alleviation period. Levels of heteronuclear NaV1.8 RNA were unaffected by SNE or shRNA treatments, suggesting that transcription of the Scn10a gene encoding NaV1.8 was unchanged. Based on these data, we postulate that increased axonal mRNA transport results in accumulation of functional NaV1.8 protein in the injured nerve and the development of painful neuropathy symptoms. Thus, targeted delivery of agents that interfere with axonal NaV1.8 mRNA may represent effective neuropathic pain treatments.
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Affiliation(s)
- Supanigar Ruangsri
- From the Jane and Jerry Weintraub Center for Reconstructive Biotechnology, Division of Advanced Prosthodontics, Biomaterials, and Hospital Dentistry
- Division of Oral Biology & Medicine, School of Dentistry, and
- the Faculty of Dentistry, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Audrey Lin
- From the Jane and Jerry Weintraub Center for Reconstructive Biotechnology, Division of Advanced Prosthodontics, Biomaterials, and Hospital Dentistry
| | | | - Kyung Lee
- From the Jane and Jerry Weintraub Center for Reconstructive Biotechnology, Division of Advanced Prosthodontics, Biomaterials, and Hospital Dentistry
| | - Igor Spigelman
- Division of Oral Biology & Medicine, School of Dentistry, and
- Brain Research Institute, UCLA, Los Angeles, California 90095 and
| | - Ichiro Nishimura
- From the Jane and Jerry Weintraub Center for Reconstructive Biotechnology, Division of Advanced Prosthodontics, Biomaterials, and Hospital Dentistry
- Division of Oral Biology & Medicine, School of Dentistry, and
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Kim CF, Moalem-Taylor G. Detailed characterization of neuro-immune responses following neuropathic injury in mice. Brain Res 2011; 1405:95-108. [DOI: 10.1016/j.brainres.2011.06.022] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Revised: 05/30/2011] [Accepted: 06/08/2011] [Indexed: 01/23/2023]
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Abstract
Neurons in the spinal dorsal horn process sensory information, which is then transmitted to several brain regions, including those responsible for pain perception. The dorsal horn provides numerous potential targets for the development of novel analgesics and is thought to undergo changes that contribute to the exaggerated pain felt after nerve injury and inflammation. Despite its obvious importance, we still know little about the neuronal circuits that process sensory information, mainly because of the heterogeneity of the various neuronal components that make up these circuits. Recent studies have begun to shed light on the neuronal organization and circuitry of this complex region.
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Affiliation(s)
- Andrew J Todd
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, West Medical Building, University of Glasgow, G12 8QQ, UK.
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Peleshok JC, Ribeiro-da-Silva A. Delayed reinnervation by nonpeptidergic nociceptive afferents of the glabrous skin of the rat hindpaw in a neuropathic pain model. J Comp Neurol 2010; 519:49-63. [DOI: 10.1002/cne.22500] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Hayashi M, Kamiya Y, Itoh H, Higashi T, Miyazaki T, Funakoshi K, Yamashita N, Goshima Y, Andoh T, Yamada Y, Goto T. Intrathecally administered Sema3A protein attenuates neuropathic pain behavior in rats with chronic constriction injury of the sciatic nerve. Neurosci Res 2010; 69:17-24. [PMID: 20888378 DOI: 10.1016/j.neures.2010.09.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Revised: 08/24/2010] [Accepted: 09/21/2010] [Indexed: 10/19/2022]
Abstract
Semaphorins, one of the repulsive axonal guidance factors during development, are produced under pathological conditions in adult animals. In the neuropathic pain state associated with peripheral nerve injury, synaptic reorganization occurs in spinal cord dorsal horn. In the present study, we investigated the roles of intrathecal administration of Sema3A, a secreted semaphorin, in the spinal cord of chronic constriction injury (CCI) model rat. Neuropilin 1 (NPR1) and Plexin A (PlexA), co-receptors of Sema3A, were expressed in the dorsal horn of naïve rats. NPR1, and not PlexA, protein expression increased in the dorsal spinal cord of CCI rats. Recombinant Sema3A protein attenuated mechanical allodynia and heat hyperalgesia in CCI rats, whereas heat-inactivated Sema3A had no effect. Immunohistochemistry revealed that Sema3A partially restored the decrease of isolectin B4-positive unmyelinated nerve terminals in lamina II of the ipsilateral dorsal horn of CCI rats. Contrary to our expectations, Sema3A did not change the distribution of myelinated fibers in lamina II at 7 days after CCI. Those results suggested that the suppressive role for Sema3A in the development of neuropathic pain associated with peripheral nerve injury in adult rats, which seemed to be independent from prevention of the myelinated fiber sprouting into lamina II.
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Affiliation(s)
- Michiko Hayashi
- Department of Anesthesiology and Critical Care Medicine, Yokohama City University Graduate School of Medicine, Kanazawa-ku, Yokohama, Japan
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Keast JR, Forrest SL, Osborne PB. Sciatic nerve injury in adult rats causes distinct changes in the central projections of sensory neurons expressing different glial cell line-derived neurotrophic factor family receptors. J Comp Neurol 2010; 518:3024-45. [PMID: 20533358 DOI: 10.1002/cne.22378] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Most small unmyelinated neurons in adult rat dorsal root ganglia (DRG) express one or more of the coreceptors targeted by glial cell line-derived neurotrophic factor (GDNF), neurturin, and artemin (GFRalpha1, GFRalpha2, and GFRalpha3, respectively). The function of these GDNF family ligands (GFLs) is not fully elucidated but recent evidence suggests GFLs could function in sensory neuron regeneration after nerve injury and peripheral nociceptor sensitization. In this study we used immunohistochemistry to determine if the DRG neurons targeted by each GFL change after sciatic nerve injury. We compared complete sciatic nerve transection and the chronic constriction model and found that the pattern of changes incurred by each injury was broadly similar. In lumbar spinal cord there was a widespread increase in neuronal GFRalpha1 immunoreactivity (IR) in the L1-6 dorsal horn. GFRalpha3-IR also increased but in a more restricted area. In contrast, GFRalpha2-IR decreased in patches of superficial dorsal horn and this loss was more extensive after transection injury. No change in calcitonin gene-related peptide-IR was detected after either injury. Analysis of double-immunolabeled L5 DRG sections suggested the main effect of injury on GFRalpha1- and GFRalpha3-IR was to increase expression in both myelinated and unmyelinated neurons. In contrast, no change in basal expression of GFRalpha2-IR was detected in DRG by analysis of fluorescence intensity and there was a small but significant reduction in GFRalpha2-IR neurons. Our results suggest that the DRG neuronal populations targeted by GDNF, neurturin, or artemin and the effect of exogenous GFLs could change significantly after a peripheral nerve injury.
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Affiliation(s)
- Janet R Keast
- Pain Management Research Institute, Kolling Institute of Medical Research, University of Sydney at Royal North Shore Hospital, St Leonards NSW 2065, Australia.
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Gladman SJ, Ward RE, Michael-Titus AT, Knight MM, Priestley JV. The effect of mechanical strain or hypoxia on cell death in subpopulations of rat dorsal root ganglion neurons in vitro. Neuroscience 2010; 171:577-87. [PMID: 20674687 DOI: 10.1016/j.neuroscience.2010.07.009] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2010] [Revised: 07/01/2010] [Accepted: 07/04/2010] [Indexed: 12/22/2022]
Abstract
Spinal nerves and their associated dorsal root ganglion (DRG) cells can be subject to mechanical deformation and hypoxia associated with pathology such as disc herniation, spinal stenosis and spine trauma. There is very limited information on the response of adult DRG neurons to such stressors. In this study we used an in vitro approach to examine the response of adult DRG cells to (a) mechanical, hypoxic, and combined injuries; and (b) to compare the effects on injury on nociceptive and non-nociceptive neurons, as well as on non-neuronal cells. Mechanical injury (20% tensile strain) led to significant neuronal cell death (assessed by ethidium homodimer-1 labelling), which was proportional to strain duration (5 min, 1 h, 6 h or 18 h). Hypoxia (2% O(2) for 24 h) also promoted death of DRG neurons, and was further enhanced when mechanical strain and hypoxia were combined. Both mechanical strain and hypoxia significantly decreased the maximum neurite length. Conversely, death of non-neuronal cells was only increased by hypoxia and not by mechanical strain. Total cell death in response to mechanical injury or hypoxia was similar in both non-nociceptive (neurofilament, NF-200 immunoreactive) and nociceptive (calcitonin gene-related peptide, CGRP immunoreactive) neurons, but apoptosis (assessed by activated caspase-3 immunostaining) was significantly higher in CGRP than NF-200 neurons. Surprisingly, cell death of non-peptidergic nociceptors (identified by Griffonia simplicifolia IB4 lectin binding) was already high in control cultures, and was not increased further by either mechanical stretch or hypoxia. These results provide detailed information on the response of adult DRG subpopulations to hypoxia and mechanical strain, and describe in vitro models that could be useful for screening potential neuroprotective agents.
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Affiliation(s)
- S J Gladman
- Centre for Neuroscience and Trauma, Blizard Institute of Cell and Molecular Science, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, E1 2AT, UK.
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Wu SX, Wang W, Li H, Wang YY, Feng YP, Li YQ. The synaptic connectivity that underlies the noxious transmission and modulation within the superficial dorsal horn of the spinal cord. Prog Neurobiol 2010; 91:38-54. [DOI: 10.1016/j.pneurobio.2010.01.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2009] [Revised: 12/10/2009] [Accepted: 01/14/2010] [Indexed: 01/27/2023]
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Pradhan AAA, Yu XH, Laird JMA. Modality of hyperalgesia tested, not type of nerve damage, predicts pharmacological sensitivity in rat models of neuropathic pain. Eur J Pain 2009; 14:503-9. [PMID: 19963418 DOI: 10.1016/j.ejpain.2009.08.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Revised: 08/03/2009] [Accepted: 08/26/2009] [Indexed: 11/18/2022]
Abstract
Although many types of nerve damage can cause neuropathic pain, there are substantial commonalities in neuropathic pain symptoms, and patients can be divided into sub-groups based on their symptom profile rather than etiology. Mechanism-based treatment suggests that pharmacotherapy should be chosen be based shared commonalities of symptoms rather than etiology. The aim of the present study was to determine whether type of injury (etiology) or behavioral endpoint (symptom) is a better predictor of pharmacological responsivity in the most commonly used rodent models of neuropathic pain. We used the chronic constriction injury (CCI) model to directly compare the temporal and pharmacological characteristics of four different types of evoked stimuli; heat, pressure, acetone cooling and punctate mechanical. We then compared heat hyperalgesia and mechanical allodynia endpoints across etiologies using the spinal nerve ligation (SNL) model. Evoked pain responses in both models had strikingly different temporal characteristics. We then tested three standard therapies for neuropathic pain from different drug classes, oxycodone, gabapentin, and amitriptyline. Notably, regardless of the model tested, or the time of onset, common endpoints showed near-identical pharmacological responses, and not all endpoints were equally sensitive to drug intervention within one model. Hypersensitivity to heat and pressure were highly responsive to oxycodone, gabapentin, and amitriptyline; whereas cold and mechanical allodynia were more difficult to reverse. Moreover, CCI- and SNL-induced mechanical allodynia was completely insensitive to amitriptyline treatment. We conclude that regardless of model and time course of presentation, different symptoms of peripheral neuropathy have unique pharmacological responses.
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Affiliation(s)
- Amynah Amir Ali Pradhan
- AstraZeneca R&D Montréal, 7171 Frédérick-Banting, Ville Saint-Laurent, Québec, Canada H4S 1Z9
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