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Cao B, Xu Q, Shi Y, Zhao R, Li H, Zheng J, Liu F, Wan Y, Wei B. Pathology of pain and its implications for therapeutic interventions. Signal Transduct Target Ther 2024; 9:155. [PMID: 38851750 PMCID: PMC11162504 DOI: 10.1038/s41392-024-01845-w] [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: 05/12/2023] [Revised: 04/08/2024] [Accepted: 04/25/2024] [Indexed: 06/10/2024] Open
Abstract
Pain is estimated to affect more than 20% of the global population, imposing incalculable health and economic burdens. Effective pain management is crucial for individuals suffering from pain. However, the current methods for pain assessment and treatment fall short of clinical needs. Benefiting from advances in neuroscience and biotechnology, the neuronal circuits and molecular mechanisms critically involved in pain modulation have been elucidated. These research achievements have incited progress in identifying new diagnostic and therapeutic targets. In this review, we first introduce fundamental knowledge about pain, setting the stage for the subsequent contents. The review next delves into the molecular mechanisms underlying pain disorders, including gene mutation, epigenetic modification, posttranslational modification, inflammasome, signaling pathways and microbiota. To better present a comprehensive view of pain research, two prominent issues, sexual dimorphism and pain comorbidities, are discussed in detail based on current findings. The status quo of pain evaluation and manipulation is summarized. A series of improved and innovative pain management strategies, such as gene therapy, monoclonal antibody, brain-computer interface and microbial intervention, are making strides towards clinical application. We highlight existing limitations and future directions for enhancing the quality of preclinical and clinical research. Efforts to decipher the complexities of pain pathology will be instrumental in translating scientific discoveries into clinical practice, thereby improving pain management from bench to bedside.
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Affiliation(s)
- Bo Cao
- Department of General Surgery, First Medical Center, Chinese PLA General Hospital, Beijing, 100853, China
| | - Qixuan Xu
- Department of General Surgery, First Medical Center, Chinese PLA General Hospital, Beijing, 100853, China
- Medical School of Chinese PLA, Beijing, 100853, China
| | - Yajiao Shi
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Key Laboratory for Neuroscience, Ministry of Education/National Health Commission, Peking University, Beijing, 100191, China
| | - Ruiyang Zhao
- Department of General Surgery, First Medical Center, Chinese PLA General Hospital, Beijing, 100853, China
- Medical School of Chinese PLA, Beijing, 100853, China
| | - Hanghang Li
- Department of General Surgery, First Medical Center, Chinese PLA General Hospital, Beijing, 100853, China
- Medical School of Chinese PLA, Beijing, 100853, China
| | - Jie Zheng
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Key Laboratory for Neuroscience, Ministry of Education/National Health Commission, Peking University, Beijing, 100191, China
| | - Fengyu Liu
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Key Laboratory for Neuroscience, Ministry of Education/National Health Commission, Peking University, Beijing, 100191, China.
| | - You Wan
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Key Laboratory for Neuroscience, Ministry of Education/National Health Commission, Peking University, Beijing, 100191, China.
| | - Bo Wei
- Department of General Surgery, First Medical Center, Chinese PLA General Hospital, Beijing, 100853, China.
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Collier L, Seah C, Hicks EM, Holtzheimer PE, Krystal JH, Girgenti MJ, Huckins LM, Johnston KJA. The impact of chronic pain on brain gene expression. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.05.20.24307630. [PMID: 38826319 PMCID: PMC11142271 DOI: 10.1101/2024.05.20.24307630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
Background Chronic pain affects one fifth of American adults, contributing significant public health burden. Chronic pain mechanisms can be further understood through investigating brain gene expression. Methods We tested differentially expressed genes (DEGs) in chronic pain, migraine, lifetime fentanyl and oxymorphone use, and with chronic pain genetic risk in four brain regions (dACC, DLPFC, MeA, BLA) and imputed cell type expression data from 304 postmortem donors. We compared findings across traits and with independent transcriptomics resources, and performed gene-set enrichment. Results We identified two chronic pain DEGs: B4GALT and VEGFB in bulk dACC. We found over 2000 (primarily BLA microglia) chronic pain cell type DEGs. Findings were enriched for mouse microglia pain genes, and for hypoxia and immune response. Cross-trait DEG overlap was minimal. Conclusions Chronic pain-associated gene expression is heterogeneous across cell type, largely distinct from that in pain-related traits, and shows BLA microglia are a key cell type.
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Affiliation(s)
- Lily Collier
- Department of Biological Sciences, Columbia University, New York City, NY
- Department of Psychiatry, Division of Molecular Psychiatry, Yale University, New Haven, CT
| | - Carina Seah
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York City, NY
| | - Emily M Hicks
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York City, NY
| | - Paul E Holtzheimer
- National Center for PTSD, U.S. Department of Veterans Affairs
- Department of Psychiatry, Geisel School of Medicine at Dartmouth, Lebanon, NH 03756, USA
| | - John H Krystal
- Department of Psychiatry, Division of Molecular Psychiatry, Yale University, New Haven, CT
- Clinical Neuroscience Division, National Center for PTSD, VA Connecticut Healthcare System, West Haven, CT
| | - Matthew J Girgenti
- Department of Psychiatry, Division of Molecular Psychiatry, Yale University, New Haven, CT
- Clinical Neuroscience Division, National Center for PTSD, VA Connecticut Healthcare System, West Haven, CT
| | - Laura M Huckins
- Department of Psychiatry, Division of Molecular Psychiatry, Yale University, New Haven, CT
| | - Keira J A Johnston
- Department of Psychiatry, Division of Molecular Psychiatry, Yale University, New Haven, CT
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Wahezi SE, Caparo MA, Malhotra R, Sundaram L, Batti K, Ejindu P, Veeramachaneni R, Anitescu M, Hunter CW, Naeimi T, Farah F, Kohan L. Current Waveforms in Spinal Cord Stimulation and Their Impact on the Future of Neuromodulation: A Scoping Review. Neuromodulation 2024; 27:47-58. [PMID: 38184341 DOI: 10.1016/j.neurom.2023.11.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Revised: 10/16/2023] [Accepted: 11/13/2023] [Indexed: 01/08/2024]
Abstract
BACKGROUND Neuromodulation is a standard and well-accepted treatment for chronic refractory neuropathic pain. There has been progressive innovation in the field over the last decade, particularly in areas of spinal cord stimulation (SCS) and dorsal root ganglion stimulation. Improved outcomes using proprietary waveforms have become customary in the field, leading to an unprecedented expansion of these products and a plethora of options for the management of pain. Although advances in waveform technology have improved our fundamental understanding of neuromodulation, a scoping review describing new energy platforms and their associated clinical effects and outcomes is needed. The authors submit that understanding electrophysiological neuromodulation may be important for clinical decision-making and programming selection for personalized patient care. OBJECTIVE This review aims to characterize ways differences in mechanism of action and clinical outcomes of current spinal neuromodulation products may affect contemporary clinical decision-making while outlining a possible path for the future SCS. STUDY DESIGN The study is a scoping review of the literature about newer generation SCS waveforms. MATERIALS AND METHODS A literature report was performed on PubMed and chapters to include articles on spine neuromodulation mechanism of action and efficacy. RESULTS A total of 8469 studies were identified, 75 of which were included for the scoping review after keywords defining recent waveform technology were added. CONCLUSIONS Clinical data suggest that neuromodulation remains a promising tool in the treatment of chronic pain. The evidence for SCS for treating chronic pain seems compelling; however, more long-term and comparative data are needed for a comparison of waveforms when it comes to the etiology of pain. In addition, an exploration into combination waveform therapy and waveform cycling may be paramount for future clinical studies and the development of new technologies.
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Affiliation(s)
- Sayed E Wahezi
- Multidisciplinary Pain Program, Montefiore Medical Center, Bronx, New York, USA.
| | - Moorice A Caparo
- Multidisciplinary Pain Program, Montefiore Medical Center, Bronx, New York, USA
| | - Ria Malhotra
- Multidisciplinary Pain Program, Montefiore Medical Center, Bronx, New York, USA
| | - Lakshman Sundaram
- Multidisciplinary Pain Program, Montefiore Medical Center, Bronx, New York, USA
| | - Kevin Batti
- Multidisciplinary Pain Program, Montefiore Medical Center, Bronx, New York, USA
| | - Prince Ejindu
- Multidisciplinary Pain Program, Montefiore Medical Center, Bronx, New York, USA
| | | | - Magdalena Anitescu
- Multidisciplinary Pain Program, Montefiore Medical Center, Bronx, New York, USA
| | - Corey W Hunter
- Multidisciplinary Pain Program, Montefiore Medical Center, Bronx, New York, USA
| | - Tahereh Naeimi
- Multidisciplinary Pain Program, Montefiore Medical Center, Bronx, New York, USA
| | - Fadi Farah
- Multidisciplinary Pain Program, Montefiore Medical Center, Bronx, New York, USA
| | - Lynn Kohan
- Multidisciplinary Pain Program, Montefiore Medical Center, Bronx, New York, USA
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Liu X, Tang SJ. Pathogenic mechanisms of human immunodeficiency virus (HIV)-associated pain. Mol Psychiatry 2023; 28:3613-3624. [PMID: 37857809 DOI: 10.1038/s41380-023-02294-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 09/25/2023] [Accepted: 10/05/2023] [Indexed: 10/21/2023]
Abstract
Chronic pain is a prevalent neurological complication among individuals living with human immunodeficiency virus (PLHIV) in the post-combination antiretroviral therapy (cART) era. These individuals experience malfunction in various cellular and molecular pathways involved in pain transmission and modulation, including the neuropathology of the peripheral sensory neurons and neurodegeneration and neuroinflammation in the spinal dorsal horn. However, the underlying etiologies and mechanisms leading to pain pathogenesis are complex and not fully understood. In this review, we aim to summarize recent progress in this field. Specifically, we will begin by examining neuropathology in the pain pathways identified in PLHIV and discussing potential causes, including those directly related to HIV-1 infection and comorbidities, such as antiretroviral drug use. We will also explore findings from animal models that may provide insights into the molecular and cellular processes contributing to neuropathology and chronic pain associated with HIV infection. Emerging evidence suggests that viral proteins and/or antiretroviral drugs trigger a complex pathological cascade involving neurons, glia, and potentially non-neural cells, and that interactions between these cells play a critical role in the pathogenesis of HIV-associated pain.
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Affiliation(s)
- Xin Liu
- Stony Brook University Pain and Analgesia Research Center (SPARC), Stony Brook University, Stony Brook, 11794, NY, USA
- Department of Anesthesiology, Renaissance School of Medicine, Stony Brook University, Stony Brook, 11794, NY, USA
| | - Shao-Jun Tang
- Stony Brook University Pain and Analgesia Research Center (SPARC), Stony Brook University, Stony Brook, 11794, NY, USA.
- Department of Anesthesiology, Renaissance School of Medicine, Stony Brook University, Stony Brook, 11794, NY, USA.
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Magni G, Riboldi B, Ceruti S. Modulation of Glial Cell Functions by the Gut-Brain Axis: A Role in Neurodegenerative Disorders and Pain Transmission. Cells 2023; 12:1612. [PMID: 37371082 DOI: 10.3390/cells12121612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 06/06/2023] [Accepted: 06/08/2023] [Indexed: 06/29/2023] Open
Abstract
Studies on host microbiota and their interactions with the central nervous system (CNS) have grown considerably in the last decade. Indeed, it has been widely demonstrated that dysregulations of the bidirectional gut-brain crosstalk are involved in the development of several pathological conditions, including chronic pain. In addition, the activation of central and peripheral glial cells is also implicated in the pathogenesis and progression of pain and other neurodegenerative disorders. Recent preclinical findings suggest that the gut microbiota plays a pivotal role in regulating glial maturation, morphology and function, possibly through the action of different microbial metabolites, including the most studied short-chain fatty acids (SCFAs). Moreover, altered microbiota composition has been reported in CNS disorders characterized by glial cell activation. In this review, we discuss recent studies showing the role of the gut microbiota and the effects of its depletion in modulating the morphology and function of glial cells (microglia and astrocytes), and we hypothesize a possible role for glia-microbiota interactions in the development and maintenance of chronic pain.
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Affiliation(s)
- Giulia Magni
- Laboratory of Pain Therapy and Neuroimmunology, Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Via Balzaretti, 9, 20133 Milan, Italy
| | - Benedetta Riboldi
- Laboratory of Pain Therapy and Neuroimmunology, Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Via Balzaretti, 9, 20133 Milan, Italy
| | - Stefania Ceruti
- Laboratory of Pain Therapy and Neuroimmunology, Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Via Balzaretti, 9, 20133 Milan, Italy
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McGinnis A, Ji RR. The Similar and Distinct Roles of Satellite Glial Cells and Spinal Astrocytes in Neuropathic Pain. Cells 2023; 12:965. [PMID: 36980304 PMCID: PMC10047571 DOI: 10.3390/cells12060965] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Revised: 03/19/2023] [Accepted: 03/20/2023] [Indexed: 03/30/2023] Open
Abstract
Preclinical studies have identified glial cells as pivotal players in the genesis and maintenance of neuropathic pain after nerve injury associated with diabetes, chemotherapy, major surgeries, and virus infections. Satellite glial cells (SGCs) in the dorsal root and trigeminal ganglia of the peripheral nervous system (PNS) and astrocytes in the central nervous system (CNS) express similar molecular markers and are protective under physiological conditions. They also serve similar functions in the genesis and maintenance of neuropathic pain, downregulating some of their homeostatic functions and driving pro-inflammatory neuro-glial interactions in the PNS and CNS, i.e., "gliopathy". However, the role of SGCs in neuropathic pain is not simply as "peripheral astrocytes". We delineate how these peripheral and central glia participate in neuropathic pain by producing different mediators, engaging different parts of neurons, and becoming active at different stages following nerve injury. Finally, we highlight the recent findings that SGCs are enriched with proteins related to fatty acid metabolism and signaling such as Apo-E, FABP7, and LPAR1. Targeting SGCs and astrocytes may lead to novel therapeutics for the treatment of neuropathic pain.
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Affiliation(s)
- Aidan McGinnis
- Center for Translational Pain Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Ru-Rong Ji
- Center for Translational Pain Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, NC 27710, USA
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
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Kristianto H, Nasution TH, Fatma EPL, Sari EK, Wibisono AH, Kurniawan H, Ratna F, Cristiningtyas I, Listyowati E. Correlation of leg pain responses with ankle-brachial index and peripheral sensory responses in foot of type 2 diabetes mellitus. HEALTHCARE IN LOW-RESOURCE SETTINGS 2023. [DOI: 10.4081/hls.2023.11173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023] Open
Abstract
Introduction: Type 2 Diabetes Mellitus (T2DM) is associated with changes that occur in the peripheral circulation that affect foot functions. Therefore, there is a need for a risk prediction test on foot abnormalities using the leg pain response parameters in T2DM patients with ankle-brachial index (ABI) and peripheral sensory changes as a preventive effort to manage foot care.
Design and Methods: This study employed a cross-sectional design in which 63 T2DM patients in a Public Health Center (PHC) in Malang were investigated. The instruments used include visual analog scale (VAS), monofilament, and foot doppler.
Results: The Pearson correlation test showed no relationship between the responses to leg pain and the ABI of the right and left feet (p-values = 0.217 and 0.692), but there was a significant relationship between the left foot ABI and sensory status (p-value 0.002; left foot r = 0.383). Meanwhile, the Pearson's correlation and linear regression test also showed a relationship between the right foot ABI and sensory status (p-value = 0.007; r = 0.338). Furthermore, a multiple linear regression test showed a relationship between the leg pain response and sensory perception of the right and left feet (p-value = 0.035; r = 0.325).
Conclusions: The relationship between the sensory status of the right and left feet and the response to leg pain in T2DM patients were moderate with a negative direction. It, therefore, implies that a decrease in the sensory responses increased the leg pain. Meanwhile, the moderate relationship and positive direction between the ABI and sensory status of the feet of T2DM patients indicates that a higher ABI score led to an increase in the sensory status of the foot.
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Fang XX, Zhai MN, Zhu M, He C, Wang H, Wang J, Zhang ZJ. Inflammation in pathogenesis of chronic pain: Foe and friend. Mol Pain 2023; 19:17448069231178176. [PMID: 37220667 DOI: 10.1177/17448069231178176] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023] Open
Abstract
Chronic pain is a refractory health disease worldwide causing an enormous economic burden on individuals and society. Accumulating evidence suggests that inflammation in the peripheral nervous system (PNS) and central nervous system (CNS) is the major factor in the pathogenesis of chronic pain. The inflammation in the early- and late phase may have distinctive effects on the initiation and resolution of pain, which can be viewed as friend or foe. On the one hand, painful injuries lead to the activation of glial cells and immune cells in the PNS, releasing pro-inflammatory mediators, which contribute to the sensitization of nociceptors, leading to chronic pain; neuroinflammation in the CNS drives central sensitization and promotes the development of chronic pain. On the other hand, macrophages and glial cells of PNS and CNS promote pain resolution via anti-inflammatory mediators and specialized pro-resolving mediators (SPMs). In this review, we provide an overview of the current understanding of inflammation in the deterioration and resolution of pain. Further, we summarize a number of novel strategies that can be used to prevent and treat chronic pain by controlling inflammation. This comprehensive view of the relationship between inflammation and chronic pain and its specific mechanism will provide novel targets for the treatment of chronic pain.
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Affiliation(s)
- Xiao-Xia Fang
- Department of Human Anatomy, School of Medicine, Nantong University, Nantong, China
| | - Meng-Nan Zhai
- Department of Human Anatomy, School of Medicine, Nantong University, Nantong, China
| | - Meixuan Zhu
- Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Cheng He
- Department of Human Anatomy, School of Medicine, Nantong University, Nantong, China
| | - Heng Wang
- Department of Human Anatomy, School of Medicine, Nantong University, Nantong, China
| | - Juan Wang
- Department of Human Anatomy, School of Medicine, Nantong University, Nantong, China
| | - Zhi-Jun Zhang
- Department of Human Anatomy, School of Medicine, Nantong University, Nantong, China
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Hornung RS, Kinchington PR, Umorin M, Kramer PR. PAQR8 and PAQR9 expression is altered in the ventral tegmental area of aged rats infected with varicella zoster virus. Mol Pain 2023; 19:17448069231202598. [PMID: 37699860 PMCID: PMC10515525 DOI: 10.1177/17448069231202598] [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: 07/06/2023] [Revised: 08/17/2023] [Accepted: 09/05/2023] [Indexed: 09/14/2023] Open
Abstract
Infection with varicella zoster virus (VZV) results in chicken pox and reactivation of VZV results in herpes zoster (HZ) or what is often referred to as shingles. Patients with HZ experience decreased motivation and increased emotional distress consistent with functions of the ventral tegmental area (VTA) of the brain. In addition, activity within the ventral tegmental area is altered in patients with HZ. HZ primarily affects individuals that are older and the VTA changes with age. To begin to determine if the VTA has a role in HZ symptoms, a screen of 10,000 genes within the VTA in young and old male rats was completed after injecting the whisker pad with VZV. The two genes that had maximal change were membrane progesterone receptors PAQR8 (mPRβ) and PAQR9 (mPRε). Neurons and non-neuronal cells expressed both PAQR8 and PAQR9. PAQR8 and PAQR9 protein expression was significantly reduced after VZV injection of young males. In old rats PAQR9 protein expression was significantly increased after VZV injection and PAQR9 protein expression was reduced in aged male rats versus young rats. Consistent with previous results, pain significantly increased after VZV injection of the whisker pad and aged animals showed significantly more pain than young animals. Our data suggests that PAQR8 and PAQR9 expression is altered by VZV injection and that these changes are affected by age.
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Affiliation(s)
- Rebecca S Hornung
- Department of Biomedical Sciences, Texas A&M University School of Dentistry, Dallas, TX, USA
| | - Paul R Kinchington
- Department of Ophthalmology and of Molecular Microbiology and Genetics, University of Pittsburgh, Pittsburgh, PA, USA
| | - Mikhail Umorin
- Department of Biomedical Sciences, Texas A&M University School of Dentistry, Dallas, TX, USA
| | - Phillip R Kramer
- Department of Biomedical Sciences, Texas A&M University School of Dentistry, Dallas, TX, USA
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de Geus TJ, Franken G, Joosten EAJ. Spinal Cord Stimulation Paradigms and Pain Relief: A Preclinical Systematic Review on Modulation of the Central Inflammatory Response in Neuropathic Pain. Neuromodulation 2023; 26:25-34. [PMID: 35931643 DOI: 10.1016/j.neurom.2022.04.049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 03/11/2022] [Accepted: 04/07/2022] [Indexed: 01/11/2023]
Abstract
OBJECTIVES Spinal cord stimulation (SCS) is a last-resort treatment for patients with chronic neuropathic pain. The mechanism underlying SCS and pain relief is not yet fully understood. Because the inflammatory balance between pro- and anti-inflammatory molecules in the spinal nociceptive network is pivotal in the development and maintenance of neuropathic pain, the working mechanism of SCS is suggested to be related to the modulation of this balance. The aim of this systematic review is to summarize and understand the effects of different SCS paradigms on the central inflammatory balance in the spinal cord. MATERIALS AND METHODS A systematic literature search was conducted using MEDLINE, Embase, and PubMed. All articles studying the effects of SCS on inflammatory or glial markers in neuropathic pain models were included. A quality assessment was performed on predetermined entities of bias. RESULTS A total of 11 articles were eligible for this systematic review. In general, induction of neuropathic pain in rats results in a proinflammatory state and at the same time an increased activity/expression of microglial and astroglial cells in the spinal cord dorsal horn. Conventional SCS seems to further enhance this proinflammatory state and increase the messenger RNA expression of microglial markers, but it also results in a decrease in microglial protein marker levels. High-frequency and especially differential targeted multiplexed SCS can not only restore the balance between pro- and anti-inflammatory molecules but also minimize the overexpression/activation of glial cells. Quality assessment and risk of bias analysis of the studies included make it clear that the results of these preclinical studies must be interpreted with caution. CONCLUSIONS In summary, the preclinical findings tend to indicate that there is a distinct SCS paradigm-related effect in the modulation of the central inflammatory balance of the spinal dorsal horn.
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Affiliation(s)
- Thomas J de Geus
- Department of Anesthesiology and Pain Management, Maastricht University Medical Centre, Maastricht, The Netherlands; Department of Translational Neuroscience, School of Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands.
| | - Glenn Franken
- Department of Anesthesiology and Pain Management, Maastricht University Medical Centre, Maastricht, The Netherlands; Department of Translational Neuroscience, School of Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Elbert A J Joosten
- Department of Anesthesiology and Pain Management, Maastricht University Medical Centre, Maastricht, The Netherlands; Department of Translational Neuroscience, School of Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands
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11
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Chen YL, Feng XL, Cheung CW, Liu JA. Mode of action of astrocytes in pain: From the spinal cord to the brain. Prog Neurobiol 2022; 219:102365. [DOI: 10.1016/j.pneurobio.2022.102365] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 09/09/2022] [Accepted: 10/07/2022] [Indexed: 11/06/2022]
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12
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Starobova H, Alshammari A, Winkler IG, Vetter I. The role of the neuronal microenvironment in sensory function and pain pathophysiology. J Neurochem 2022. [PMID: 36394416 DOI: 10.1111/jnc.15724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 11/10/2022] [Accepted: 11/16/2022] [Indexed: 11/19/2022]
Abstract
The high prevalence of pain and the at times low efficacy of current treatments represent a significant challenge to healthcare systems worldwide. Effective treatment strategies require consideration of the diverse pathophysiologies that underlie various pain conditions. Indeed, our understanding of the mechanisms contributing to aberrant sensory neuron function has advanced considerably. However, sensory neurons operate in a complex dynamic microenvironment that is controlled by multidirectional interactions of neurons with non-neuronal cells, including immune cells, neuronal accessory cells, fibroblasts, adipocytes, and keratinocytes. Each of these cells constitute and control the microenvironment in which neurons operate, inevitably influencing sensory function and the pathology of pain. This review highlights the importance of the neuronal microenvironment for sensory function and pain, focusing on cellular interactions in the skin, nerves, dorsal root ganglia, and spinal cord. We discuss the current understanding of the mechanisms by which neurons and non-neuronal cells communicate to promote or resolve pain, and how this knowledge could be used for the development of mechanism-based treatments.
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Affiliation(s)
- Hana Starobova
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland, Australia
| | - Ammar Alshammari
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland, Australia
| | - Ingrid G Winkler
- Mater Research Institute, The University of Queensland, Queensland, South Brisbane, Australia
| | - Irina Vetter
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland, Australia
- The School of Pharmacy, The University of Queensland, Woolloongabba, Queensland, Australia
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Hu R, Shi M, Xu H, Wu X, He K, Chen Y, Wu L, Ma R. Integrated bioinformatics analysis identifies the effects of Sema3A/NRP1 signaling in oligodendrocytes after spinal cord injury in rats. PeerJ 2022; 10:e13856. [PMID: 35990904 PMCID: PMC9390322 DOI: 10.7717/peerj.13856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 07/16/2022] [Indexed: 01/18/2023] Open
Abstract
Objective To investigate the effect of Sema3A/NRP1 signaling in oligodendrocytes (OLs) after spinal cord injury. Methods Three analysis strategies, namely differential expression gene analysis, Gene Ontology (GO) enrichment, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, were applied. The protein-protein interaction (PPI) network was constructed using the STRING website to explore the correlation between Sema3A/NRP1 and oligodendrocytes. Then, the T10 spinal cord segment of rats was injured by the Allen method to establish a spinal cord injury (SCI) model. Real-time quantitative PCR, Western blotting, Nissl staining and immunofluorescence staining were used to detect the effect of Sema3A/NRP1 signaling on oligodendrocytes in vivo. Results After the SCI model was established, significantly fewer oligodendrocytes were observed. At the same time, R software was used to analyze the expression of related genes, and NRP1 expression was increased. PCR also demonstrated similar results, and NRP1 ligand Sema3A was also upregulated. KEGG and GO functional enrichment analysis indicated that the SCI model was mainly related to cytokine interaction, cell proliferation, differentiation and maturation. Interestingly, we found that NRP1 was involved in semaphorin-plexin signaling pathway neuronal projection guidance and axon guidance, mediating cell growth and migration. Moreover, Sema3A/NRP1 signaling was closely associated with platelet-derived growth factor receptor α (PDGFRα) in the PPI network. When Sema3A/NRP1 signaling was specifically blocked at early stages, PDGFRα expression was effectively inhibited, and the expression of OLs was promoted. Furthermore, inhibition of Sema3A/NRP1 signaling increased the Basso-Beattie-Bresnahan (BBB) score of lower limb motor function in SCI rats and promoted the survival of motor neurons in the ventral horn of the injured spinal cord. Conclusion Our data suggest that Sema3A/NRP1 signaling may regulate the development of OPCs and OLs after SCI, thereby affecting functional recovery.
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Affiliation(s)
- Rong Hu
- Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Third School of Clinical Medicine (School of Rehabilitation Medicine), HangZhou, China
| | - Mengting Shi
- Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Third School of Clinical Medicine (School of Rehabilitation Medicine), HangZhou, China
| | - Haipeng Xu
- Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Third School of Clinical Medicine (School of Rehabilitation Medicine), HangZhou, China
| | - Xingying Wu
- Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Third School of Clinical Medicine (School of Rehabilitation Medicine), HangZhou, China
| | - Kelin He
- Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Third School of Clinical Medicine (School of Rehabilitation Medicine), HangZhou, China,Department of Acupuncture and Moxibustion, The Third Affiliated Hospital of Zhejiang Chinese Medical University (Zhongshan Hospital of Zhejiang Province), HangZhou, China
| | - Yi Chen
- Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Third School of Clinical Medicine (School of Rehabilitation Medicine), HangZhou, China
| | - Lei Wu
- Department of Acupuncture and Moxibustion, The Third Affiliated Hospital of Zhejiang Chinese Medical University (Zhongshan Hospital of Zhejiang Province), HangZhou, China
| | - Ruijie Ma
- Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Third School of Clinical Medicine (School of Rehabilitation Medicine), HangZhou, China,Department of Acupuncture and Moxibustion, The Third Affiliated Hospital of Zhejiang Chinese Medical University (Zhongshan Hospital of Zhejiang Province), HangZhou, China
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14
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Central Neuropathic Pain Syndromes: Current and Emerging Pharmacological Strategies. CNS Drugs 2022; 36:483-516. [PMID: 35513603 DOI: 10.1007/s40263-022-00914-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/10/2022] [Indexed: 12/31/2022]
Abstract
Central neuropathic pain is caused by a disease or lesion of the brain or spinal cord. It is difficult to predict which patients will develop central pain syndromes after a central nervous system injury, but depending on the etiology, lifetime prevalence may be greater than 50%. The resulting pain is often highly distressing and difficult to treat, with no specific treatment guidelines currently available. This narrative review discusses mechanisms contributing to central neuropathic pain, and focuses on pharmacological approaches for managing common central neuropathic pain conditions such as central post-stroke pain, spinal cord injury-related pain, and multiple sclerosis-related neuropathic pain. Tricyclic antidepressants, serotonin-norepinephrine reuptake inhibitors, and gabapentinoids have some evidence for efficacy in central neuropathic pain. Medications from other pharmacologic classes may also provide pain relief, but current evidence is limited. Certain non-pharmacologic approaches, neuromodulation in particular, may be helpful in refractory cases. Emerging data suggest that modulating the primary afferent input may open new horizons for the treatment of central neuropathic pain. For most patients, effective treatment will likely require a multimodal therapy approach.
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15
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Younis A, Hardowar L, Barker S, Hulse RP. The consequence of endothelial remodelling on the blood spinal cord barrier and nociception. Curr Res Physiol 2022; 5:184-192. [PMID: 35434652 PMCID: PMC9010889 DOI: 10.1016/j.crphys.2022.03.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 03/09/2022] [Accepted: 03/30/2022] [Indexed: 12/01/2022] Open
Abstract
Nociception is a fundamental acute protective mechanism that prevents harm to an organism. Understanding the integral processes that control nociceptive processing are fundamental to our appreciation of which cellular and molecular features underlie this process. There is an extensive understanding of how sensory neurons interpret differing sensory modalities and intensities. However, it is widely appreciated that the sensory neurons do not act alone. These work in harmony with inflammatory and vascular systems to modulate pain perception. The spinal cord has an extensive interaction with the capillary network in the form of a blood spinal cord barrier to ensure homeostatic control of the spinal cord neuron milieu. However, there is an extensive appreciation that disturbances in the blood spinal cord barrier contribute to the onset of chronic pain. Enhanced vascular permeability and impaired blood perfusion have both been highlighted as contributors to chronic pain manifestation. Here, we discuss the evidence that demonstrates alterations in the blood spinal cord barrier influences nociceptive processing and perception of pain.
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Affiliation(s)
- Awais Younis
- School of Science and Technology, Nottingham Trent University, Nottingham, NG11 8NS, UK
| | - Lydia Hardowar
- School of Science and Technology, Nottingham Trent University, Nottingham, NG11 8NS, UK
| | - Sarah Barker
- School of Science and Technology, Nottingham Trent University, Nottingham, NG11 8NS, UK
| | - Richard Philip Hulse
- School of Science and Technology, Nottingham Trent University, Nottingham, NG11 8NS, UK
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16
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Abstract
Inflammatory pain is the perception of noxious stimuli that occurs during inflammation or an immune response. Glial cells are widespread in the central and peripheral nervous systems, supporting and guiding the migration of neurons, participating in the immune response, forming the myelin sheath and blood-brain barrier, and maintaining the concentration of potassium ions outside nerve cells. Recent studies have shown that glial cells have a significant connection with the production and development of inflammatory pain. This article reviews the relationship, mechanisms, therapeutic targets between five types of glial cells and inflammatory pain, and the medicine composition that can effectively inhibit inflammatory pain. It expands the study on the mechanism of glial cells regulating pain and provides new ideas for the therapy of inflammatory pain.
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Affiliation(s)
- Hongji Wang
- Department of Physiology, Basic Medical College of Nanchang University, Nanchang 330006, P.R. China
| | - Changshui Xu
- Department of Physiology, Basic Medical College of Nanchang University, Nanchang 330006, P.R. China
- The Clinical Medical School, Jiangxi Medical College, Shangrao 334000, P.R. China
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17
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Chen JF, Wang F, Huang NX, Xiao L, Mei F. Oligodendrocytes and Myelin: Active players in Neurodegenerative brains? Dev Neurobiol 2022; 82:160-174. [PMID: 35081276 DOI: 10.1002/dneu.22867] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 01/18/2022] [Accepted: 01/19/2022] [Indexed: 11/10/2022]
Abstract
Oligodendrocytes (OLs) are a major type of glial cells in the central nervous system that generate multiple myelin sheaths to wrap axons. Myelin ensures fast and efficient propagation of action potentials along axons and supports neurons with nourishment. The decay of OLs and myelin has been implicated in age-related neurodegenerative diseases and these changes are generally considered as an inevitable result of neuron loss and axon degeneration. Noticeably, OLs and myelin undergo dynamic changes in healthy adult brains, that is, newly formed OLs are continuously added throughout life from the differentiation of oligodendrocyte precursor cells (OPCs) and the pre-existing myelin sheaths may undergo degeneration or remodeling. Increasing evidence has shown that changes in OLs and myelin are present in the early stages of neurodegenerative diseases, and even prior to significant neuronal loss and functional deficits. More importantly, oligodendroglia-specific manipulation, by either deletion of the disease gene or enhancement of myelin renewal, can alleviate functional impairments in neurodegenerative animal models. These findings underscore the possibility that OLs and myelin are not passively but actively involved in neurodegenerative diseases and may play an important role in modulating neuronal function and survival. In this review, we summarize recent work characterizing OL and myelin changes in both healthy and neurodegenerative brains and discuss the potential of targeting oligodendroglial cells in treating neurodegenerative diseases. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Jing-Fei Chen
- Brain and Intelligence Research Key Laboratory of Chongqing Education Commission, Department of Histology and Embryology, Third Military Medical University, Chongqing, 400038, China
| | - Fei Wang
- Brain and Intelligence Research Key Laboratory of Chongqing Education Commission, Department of Histology and Embryology, Third Military Medical University, Chongqing, 400038, China
| | - Nan-Xing Huang
- Brain and Intelligence Research Key Laboratory of Chongqing Education Commission, Department of Histology and Embryology, Third Military Medical University, Chongqing, 400038, China
| | - Lan Xiao
- Brain and Intelligence Research Key Laboratory of Chongqing Education Commission, Department of Histology and Embryology, Third Military Medical University, Chongqing, 400038, China
| | - Feng Mei
- Brain and Intelligence Research Key Laboratory of Chongqing Education Commission, Department of Histology and Embryology, Third Military Medical University, Chongqing, 400038, China
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18
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Acid-Sensing Ion Channels in Glial Cells. MEMBRANES 2022; 12:membranes12020119. [PMID: 35207041 PMCID: PMC8878633 DOI: 10.3390/membranes12020119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 12/29/2021] [Accepted: 01/17/2022] [Indexed: 12/13/2022]
Abstract
Acid-sensing ion channels (ASICs) are proton-gated cation channels and key mediators of responses to neuronal injury. ASICs exhibit unique patterns of distribution in the brain, with high expression in neurons and low expression in glial cells. While there has been a lot of focus on ASIC in neurons, less is known about the roles of ASICs in glial cells. ASIC1a is expressed in astrocytes and might contribute to synaptic transmission and long-term potentiation. In oligodendrocytes, constitutive activation of ASIC1a participates in demyelinating diseases. ASIC1a, ASIC2a, and ASIC3, found in microglial cells, could mediate the inflammatory response. Under pathological conditions, ASIC dysregulation in glial cells can contribute to disease states. For example, activation of astrocytic ASIC1a may worsen neurodegeneration and glioma staging, activation of microglial ASIC1a and ASIC2a may perpetuate ischemia and inflammation, while oligodendrocytic ASIC1a might be involved in multiple sclerosis. This review concentrates on the unique ASIC components in each of the glial cells and integrates these glial-specific ASICs with their physiological and pathological conditions. Such knowledge provides promising evidence for targeting of ASICs in individual glial cells as a therapeutic strategy for a diverse range of conditions.
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19
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Wang XX, Cui LL, Gan SF, Zhang ZR, Xiao J, Li CH, Luo F. Inhibition of Oligodendrocyte Apoptosis in the Prelimbic Medial Prefrontal Cortex Prevents Fentanyl-induced Hyperalgesia in Rats. THE JOURNAL OF PAIN 2022; 23:1035-1050. [PMID: 35021116 DOI: 10.1016/j.jpain.2021.12.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 12/02/2021] [Accepted: 12/20/2021] [Indexed: 11/16/2022]
Abstract
Opioid-induced hyperalgesia (OIH) is a problem associated with prolonged use of opioids in chronic pain management, and its effective treatment has been hampered by lack of mechanistic evidence. Oligodendrocytes have recently been linked with several pain-related diseases; however, little is known its role in OIH. The prelimbic medial prefrontal cortex (PL-mPFC) has emerged as a significant center of pain regulation, and is rich in oligodendrocytes. Herein we explored the effect of oligodendrocyte apoptosis of PL-mPFC on OIH. Using a fentanyl-induced rat model of OIH and proteomics analysis of the PL-mPFC, we observed a downregulation in 5 types of myelin-related proteins originating from oligodendrocytes; this was further verified by western blotting. Meanwhile, cleaved-caspase 3 (an apoptosis marker) was increased, whereas the oligodendrocyte precursor cell (OPC) marker NG2 remained unchanged. These results suggest that downregulated myelin-related proteins may be associated with oligodendrocyte apoptosis rather than a reduction in their generating source, and immunohistochemistry confirmed this hypothesis. Behaviorally, prophylactic blockade of oligodendrocyte apoptosis by microinjection of z-DEVD-fmk into the PL-mPFC prevented fentanyl-induced mechanical and thermal hyperalgesia, but downregulated myelin basic protein (mbp) gradually recovered in 12 h. We suggest that OIH may be primed in part via oligodendrocyte apoptosis in the PL-mPFC. PERSPECTIVE: In this study we showed that oligodendrocyte apoptosis in the PL-mPFC is a key trigger for fentanyl-induced hyperalgesia. Targeting oligodendrocyte apoptosis in the PL-mPFC may prevented hyperalgesia priming induced by fentanyl.
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Affiliation(s)
- Xi-Xi Wang
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Ling-Ling Cui
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Si-Fei Gan
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Ze-Ru Zhang
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Jing Xiao
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Chen-Hong Li
- The Laboratory of Membrane Ion Channels and Medicine, Key Laboratory of Cognitive Science, State Ethnic Affairs Commission, College of Biomedical Engineering, South-Central University for Nationalities, Wuhan, Hubei, China
| | - Fang Luo
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.
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20
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Ki SM, Jeong HS, Lee JE. Primary Cilia in Glial Cells: An Oasis in the Journey to Overcoming Neurodegenerative Diseases. Front Neurosci 2021; 15:736888. [PMID: 34658775 PMCID: PMC8514955 DOI: 10.3389/fnins.2021.736888] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 08/31/2021] [Indexed: 12/29/2022] Open
Abstract
Many neurodegenerative diseases have been associated with defects in primary cilia, which are cellular organelles involved in diverse cellular processes and homeostasis. Several types of glial cells in both the central and peripheral nervous systems not only support the development and function of neurons but also play significant roles in the mechanisms of neurological disease. Nevertheless, most studies have focused on investigating the role of primary cilia in neurons. Accordingly, the interest of recent studies has expanded to elucidate the role of primary cilia in glial cells. Correspondingly, several reports have added to the growing evidence that most glial cells have primary cilia and that impairment of cilia leads to neurodegenerative diseases. In this review, we aimed to understand the regulatory mechanisms of cilia formation and the disease-related functions of cilia, which are common or specific to each glial cell. Moreover, we have paid close attention to the signal transduction and pathological mechanisms mediated by glia cilia in representative neurodegenerative diseases. Finally, we expect that this field of research will clarify the mechanisms involved in the formation and function of glial cilia to provide novel insights and ideas for the treatment of neurodegenerative diseases in the future.
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Affiliation(s)
- Soo Mi Ki
- Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Seoul, South Korea
| | - Hui Su Jeong
- Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Seoul, South Korea
| | - Ji Eun Lee
- Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Seoul, South Korea.,Samsung Medical Center, Samsung Biomedical Research Institute, Seoul, South Korea
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21
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Ding YQ, Qi JG. Sensory root demyelination: Transforming touch into pain. Glia 2021; 70:397-413. [PMID: 34549463 DOI: 10.1002/glia.24097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 09/07/2021] [Accepted: 09/09/2021] [Indexed: 11/12/2022]
Abstract
The normal feeling of touch is vital for nearly every aspect of our daily life. However, touching is not always felt as touch, but also abnormally as pain under numerous diseased conditions. For either mechanistic understanding of the faithful feeling of touch or clinical management of chronic pain, there is an essential need to thoroughly dissect the neuropathological changes that lead to painful touch or tactile allodynia and their corresponding cellular and molecular underpinnings. In recent years, we have seen remarkable progress in our understanding of the neural circuits for painful touch, with an increasing emphasis on the upstream roles of non-neuronal cells. As a highly specialized form of axon ensheathment by glial cells in jawed vertebrates, myelin sheaths not only mediate their outstanding neural functions via saltatory impulse propagation of temporal and spatial precision, but also support long-term neuronal/axonal integrity via metabolic and neurotrophic coupling. Therefore, myelinopathies have been implicated in diverse neuropsychiatric diseases, which are traditionally recognized as a result of the dysfunctions of neural circuits. However, whether myelinopathies can transform touch into pain remains a long-standing question. By summarizing and reframing the fragmentary but accumulating evidence so far, the present review indicates that sensory root demyelination represents a hitherto underappreciated neuropathological change for most neuropathic conditions of painful touch and offers an insightful window into faithful tactile sensation as well as a potential therapeutic target for intractable painful touch.
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Affiliation(s)
- You-Quan Ding
- Department of Histology, Embryology and Neurobiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, Sichuan, China
| | - Jian-Guo Qi
- Department of Histology, Embryology and Neurobiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, Sichuan, China
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22
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Hu XM, Yang W, Zhang MT, Du LX, Tian JH, Zhu JY, Chen Y, Hai F, Liu SB, Mao-Ying QL, Chu YX, Zhou H, Wang YQ, Mi WL. Glial IL-33 signaling through an ST2-to-CXCL12 pathway in the spinal cord contributes to morphine-induced hyperalgesia and tolerance. Sci Signal 2021; 14:eabe3773. [PMID: 34516755 DOI: 10.1126/scisignal.abe3773] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
[Figure: see text].
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Affiliation(s)
- Xue-Ming Hu
- Department of Integrative Medicine and Neurobiology, School of Basic Medical Science, Institutes of Integrative Medicine, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Wei Yang
- Department of Integrative Medicine and Neurobiology, School of Basic Medical Science, Institutes of Integrative Medicine, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Meng-Ting Zhang
- Department of Integrative Medicine and Neurobiology, School of Basic Medical Science, Institutes of Integrative Medicine, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai 200032, China.,Department of Encephalopathy, Jinhua Hospital of Traditional Chinese Medicine, Jinhua, Zhejiang 321017, China
| | - Li-Xia Du
- Department of Integrative Medicine and Neurobiology, School of Basic Medical Science, Institutes of Integrative Medicine, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Jia-He Tian
- Department of Integrative Medicine and Neurobiology, School of Basic Medical Science, Institutes of Integrative Medicine, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Jian-Yu Zhu
- Department of Integrative Medicine and Neurobiology, School of Basic Medical Science, Institutes of Integrative Medicine, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Yu Chen
- Department of Integrative Medicine and Neurobiology, School of Basic Medical Science, Institutes of Integrative Medicine, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Feng Hai
- Department of Integrative Medicine and Neurobiology, School of Basic Medical Science, Institutes of Integrative Medicine, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Shen-Bin Liu
- Department of Integrative Medicine and Neurobiology, School of Basic Medical Science, Institutes of Integrative Medicine, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Qi-Liang Mao-Ying
- Department of Integrative Medicine and Neurobiology, School of Basic Medical Science, Institutes of Integrative Medicine, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai 200032, China.,Shanghai Key Laboratory of Acupuncture Mechanism and Acupoint Function, Fudan University, Shanghai 200032, China
| | - Yu-Xia Chu
- Department of Integrative Medicine and Neurobiology, School of Basic Medical Science, Institutes of Integrative Medicine, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai 200032, China.,Shanghai Key Laboratory of Acupuncture Mechanism and Acupoint Function, Fudan University, Shanghai 200032, China
| | - Hong Zhou
- Department of Immunology, Anhui Medical University, Hefei, Anhui 230032, China
| | - Yan-Qing Wang
- Department of Integrative Medicine and Neurobiology, School of Basic Medical Science, Institutes of Integrative Medicine, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai 200032, China.,Shanghai Key Laboratory of Acupuncture Mechanism and Acupoint Function, Fudan University, Shanghai 200032, China
| | - Wen-Li Mi
- Department of Integrative Medicine and Neurobiology, School of Basic Medical Science, Institutes of Integrative Medicine, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai 200032, China.,Shanghai Key Laboratory of Acupuncture Mechanism and Acupoint Function, Fudan University, Shanghai 200032, China
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23
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Cedeño DL, Kelley CA, Chakravarthy K, Vallejo R. Modulation of Glia-Mediated Processes by Spinal Cord Stimulation in Animal Models of Neuropathic Pain. FRONTIERS IN PAIN RESEARCH 2021; 2:702906. [PMID: 35295479 PMCID: PMC8915735 DOI: 10.3389/fpain.2021.702906] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 05/31/2021] [Indexed: 12/23/2022] Open
Abstract
Glial cells play an essential role in maintaining the proper functioning of the nervous system. They are more abundant than neurons in most neural tissues and provide metabolic and catabolic regulation, maintaining the homeostatic balance at the synapse. Chronic pain is generated and sustained by the disruption of glia-mediated processes in the central nervous system resulting in unbalanced neuron–glial interactions. Animal models of neuropathic pain have been used to demonstrate that changes in immune and neuroinflammatory processes occur in the course of pain chronification. Spinal cord stimulation (SCS) is an electrical neuromodulation therapy proven safe and effective for treating intractable chronic pain. Traditional SCS therapies were developed based on the gate control theory of pain and rely on stimulating large Aβ neurons to induce paresthesia in the painful dermatome intended to mask nociceptive input carried out by small sensory neurons. A paradigm shift was introduced with SCS treatments that do not require paresthesia to provide effective pain relief. Efforts to understand the mechanism of action of SCS have considered the role of glial cells and the effect of electrical parameters on neuron–glial interactions. Recent work has provided evidence that SCS affects expression levels of glia-related genes and proteins. This inspired the development of a differential target multiplexed programming (DTMP) approach using electrical signals that can rebalance neuroglial interactions by targeting neurons and glial cells differentially. Our group pioneered the utilization of transcriptomic and proteomic analyses to identify the mechanism of action by which SCS works, emphasizing the DTMP approach. This is an account of evidence demonstrating the effect of SCS on glia-mediated processes using neuropathic pain models, emphasizing studies that rely on the evaluation of large sets of genes and proteins. We show that SCS using a DTMP approach strongly affects the expression of neuron and glia-specific transcriptomes while modulating them toward expression levels of healthy animals. The ability of DTMP to modulate key genes and proteins involved in glia-mediated processes affected by pain toward levels found in uninjured animals demonstrates a shift in the neuron–glial environment promoting analgesia.
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Affiliation(s)
- David L. Cedeño
- Research and Development, Lumbrera LLC, Bloomington, IL, United States
- Department of Psychology, Illinois Wesleyan University, Bloomington, IL, United States
- *Correspondence: David L. Cedeño
| | - Courtney A. Kelley
- Department of Psychology, Illinois Wesleyan University, Bloomington, IL, United States
| | - Krishnan Chakravarthy
- Deparment of Anesthesiology and Pain Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Ricardo Vallejo
- Research and Development, Lumbrera LLC, Bloomington, IL, United States
- Department of Psychology, Illinois Wesleyan University, Bloomington, IL, United States
- Research Department, National Spine and Pain Center, Bloomington, IL, United States
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24
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Vallejo R, Kelley CA, Gupta A, Smith WJ, Vallejo A, Cedeño DL. Modulation of neuroglial interactions using differential target multiplexed spinal cord stimulation in an animal model of neuropathic pain. Mol Pain 2021; 16:1744806920918057. [PMID: 32290778 PMCID: PMC7160773 DOI: 10.1177/1744806920918057] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The development and maintenance of chronic neuropathic pain involves distorted
neuroglial interactions, which result in prolonged perturbations of immune and
inflammatory response, as well as disrupted synapses and cellular interactions.
Spinal cord stimulation (SCS) has proven effective and safe for more than
40 years, but comprehensive understanding of its mode of action remains elusive.
Previous work in our laboratory provided evidence that conventional SCS
parameters modulate biological processes associated with neuropathic pain in
animals. This inspired the development of differential target multiplexed
programming (DTMP) in which multiple electrical signals are used for modulating
glial cells and neurons in order to rebalance their interactions. This work
compares DTMP with both low rate and high rate programming using an animal model
of neuropathic pain. The spared nerve injury model was implemented in 48 rats
equally randomized into four experimental groups: No-SCS, DTMP, low rate, and
high rate. Naive animals (N = 7) served as a reference control. SCS was applied
continuously for 48 h and pain-related behavior assessed before and after SCS.
RNA from the spinal cord exposed to SCS was sequenced to determine changes in
gene expression as a result of injury (No-SCS vs. naïve) and as a result of SCS
(SCS vs. No-SCS). Bioinformatics tools (Weighted Gene Co-expression Network
Analysis and Gene Ontology Enrichment Analysis) were used to evaluate the
significance of the results. All three therapies significantly reduced
mechanical hypersensitivity, although DTMP provided statistically better results
overall. DTMP also reduced thermal hypersensitivity significantly.
RNA-sequencing corroborated the complex effects of nerve injury on the
transcriptome. In addition, DTMP provided significantly more effective
modulation of genes associated with pain-related processes in returning their
expression toward levels observed in naïve, noninjured animals. DTMP provides a
more effective way of modulating the expression of genes involved in
pain-relevant biological processes associated with neuroglial interactions.
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Affiliation(s)
- Ricardo Vallejo
- Department of Basic Science, Millennium Pain Center, Bloomington, IL, USA.,Department of Psychology, Illinois Wesleyan University, Bloomington, IL, USA
| | - Courtney A Kelley
- Department of Basic Science, Millennium Pain Center, Bloomington, IL, USA.,Department of Psychology, Illinois Wesleyan University, Bloomington, IL, USA
| | - Ashim Gupta
- Department of Basic Science, Millennium Pain Center, Bloomington, IL, USA.,Department of Psychology, Illinois Wesleyan University, Bloomington, IL, USA.,Department of Research, South Texas Orthopaedic Research Institute, Laredo, TX, USA
| | - William J Smith
- Department of Basic Science, Millennium Pain Center, Bloomington, IL, USA.,Geisel School of Medicine, Dartmouth College, Hanover, NH, USA
| | - Alejandro Vallejo
- Department of Basic Science, Millennium Pain Center, Bloomington, IL, USA
| | - David L Cedeño
- Department of Basic Science, Millennium Pain Center, Bloomington, IL, USA.,Department of Psychology, Illinois Wesleyan University, Bloomington, IL, USA
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25
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Lin JY, Zhu N, He YN, Xu BL, Peng B. Stereological study on the numerical plasticity of myelinated fibers and oligodendrocytes in the rat spinal cord with painful diabetic neuropathy. Neuroreport 2021; 31:319-324. [PMID: 32058434 PMCID: PMC7041624 DOI: 10.1097/wnr.0000000000001407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Painful diabetic neuropathy may associate with nerve morphological plasticity in both peripheral and central nervous system. The aim of this study was to determine numerical changes of myelinated fibers in the spinothalamic tract region and oligodendrocytes in the spinal dorsal horn of rats with painful diabetic neuropathy and the effects of metformin on the above changes. Male Sprague–Dawley rats were randomly allocated into the control group (n = 7), the painful diabetic neuropathy group (n = 6) and the painful diabetic neuropathy treated with metformin group (the PDN + M group, n = 7), respectively. Twenty-eight days after medication, numbers of myelinated fibers in the spinothalamic tract and oligodendrocytes in the spinal dorsal horn were estimated by the optical disector (a stereological technique). Compared to the control group, number of myelinated fibers in the spinothalamic tract increased significantly in the painful diabetic neuropathy and PDN + M group, compared to the painful diabetic neuropathy group, number of myelinated fibers decreased in the PDN + M group (P < 0.05). As the oligodendrocyte in the spinal dorsal horn was considered, its number increased significantly in the painful diabetic neuropathy group compared to the control and the PDN + M group (P < 0.05), there was no significant difference between the control and the PDN + M group (P > 0.05). Our results indicate that painful diabetic neuropathy is associated with a serial of morphometric plasticity in the rat spinal cord including the numerical increase of the myelinated fibers in the spinothalamic tract and the oligodendrocytes in the spinal dorsal horn. The analgesic effect of metformin against painful diabetic neuropathy might be related to its adverse effects on the above morphometric plasticity.
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Affiliation(s)
- Jing-Yan Lin
- Department of Anesthesiology, Affiliated Hospital of North Sichuan Medical College, Nanchong
| | - Na Zhu
- Department of Anesthesiology, Affiliated Hospital of North Sichuan Medical College, Nanchong.,Department of Anesthesiology, the First Affiliated Hospital of Chengdu Medical College, Chengdu
| | - Yi-Na He
- Department of Anesthesiology, Affiliated Hospital of North Sichuan Medical College, Nanchong.,Department of Anesthesiology, Nanchong Central Hospital, Nanchong
| | - Bo-Lin Xu
- Department of Anesthesiology, Santai County People's Hospital (Affiliated Hospital of North Sichuan Medical College in Santai County), Mianyang
| | - Bin Peng
- Research Unit of Electron Microscopy Structures, North Sichuan Medical College, Nanchong, Sichuan, China
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26
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Titus HE, Chen Y, Podojil JR, Robinson AP, Balabanov R, Popko B, Miller SD. Pre-clinical and Clinical Implications of "Inside-Out" vs. "Outside-In" Paradigms in Multiple Sclerosis Etiopathogenesis. Front Cell Neurosci 2020; 14:599717. [PMID: 33192332 PMCID: PMC7654287 DOI: 10.3389/fncel.2020.599717] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 10/06/2020] [Indexed: 12/15/2022] Open
Abstract
Multiple Sclerosis (MS) is an immune-mediated neurological disorder, characterized by central nervous system (CNS) inflammation, oligodendrocyte loss, demyelination, and axonal degeneration. Although autoimmunity, inflammatory demyelination and neurodegeneration underlie MS, the initiating event has yet to be clarified. Effective disease modifying therapies need to both regulate the immune system and promote restoration of neuronal function, including remyelination. The challenge in developing an effective long-lived therapy for MS requires that three disease-associated targets be addressed: (1) self-tolerance must be re-established to specifically inhibit the underlying myelin-directed autoimmune pathogenic mechanisms; (2) neurons must be protected from inflammatory injury and degeneration; (3) myelin repair must be engendered by stimulating oligodendrocyte progenitors to remyelinate CNS neuronal axons. The combined use of chronic and relapsing remitting experimental autoimmune encephalomyelitis (C-EAE, R-EAE) (“outside-in”) as well as progressive diphtheria toxin A chain (DTA) and cuprizone autoimmune encephalitis (CAE) (“inside-out”) mouse models allow for the investigation and specific targeting of all three of these MS-associated disease parameters. The “outside-in” EAE models initiated by myelin-specific autoreactive CD4+ T cells allow for the evaluation of both myelin-specific tolerance in the absence or presence of neuroprotective and/or remyelinating agents. The “inside-out” mouse models of secondary inflammatory demyelination are triggered by toxin-induced oligodendrocyte loss or subtle myelin damage, which allows evaluation of novel therapeutics that could promote remyelination and neuroprotection in the CNS. Overall, utilizing these complementary pre-clinical MS models will open new avenues for developing therapeutic interventions, tackling MS from the “outside-in” and/or “inside-out”.
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Affiliation(s)
- Haley E Titus
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Yanan Chen
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Joseph R Podojil
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States.,Cour Pharmaceutical Development Company, Inc., Northbrook, IL, United States
| | - Andrew P Robinson
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Roumen Balabanov
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Brian Popko
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Stephen D Miller
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States.,Cour Pharmaceutical Development Company, Inc., Northbrook, IL, United States.,Interdepartmental Immunobiology Center, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
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27
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Sen MK, Almuslehi MSM, Shortland PJ, Coorssen JR, Mahns DA. Revisiting the Pathoetiology of Multiple Sclerosis: Has the Tail Been Wagging the Mouse? Front Immunol 2020; 11:572186. [PMID: 33117365 PMCID: PMC7553052 DOI: 10.3389/fimmu.2020.572186] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Accepted: 08/27/2020] [Indexed: 12/18/2022] Open
Abstract
Multiple Sclerosis (MS) is traditionally considered an autoimmune-mediated demyelinating disease, the pathoetiology of which is unknown. However, the key question remains whether autoimmunity is the initiator of the disease (outside-in) or the consequence of a slow and as yet uncharacterized cytodegeneration (oligodendrocytosis), which leads to a subsequent immune response (inside-out). Experimental autoimmune encephalomyelitis has been used to model the later stages of MS during which the autoimmune involvement predominates. In contrast, the cuprizone (CPZ) model is used to model early stages of the disease during which oligodendrocytosis and demyelination predominate and are hypothesized to precede subsequent immune involvement in MS. Recent studies combining a boost, or protection, to the immune system with disruption of the blood brain barrier have shown CPZ-induced oligodendrocytosis with a subsequent immune response. In this Perspective, we review these recent advances and discuss the likelihood of an inside-out vs. an outside-in pathoetiology of MS.
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Affiliation(s)
- Monokesh K Sen
- School of Medicine, Western Sydney University, Penrith, NSW, Australia
| | - Mohammed S M Almuslehi
- School of Medicine, Western Sydney University, Penrith, NSW, Australia.,Department of Physiology, College of Veterinary Medicine, University of Diyala, Baqubah, Iraq
| | - Peter J Shortland
- School of Science, Western Sydney University, Penrith, NSW, Australia
| | - Jens R Coorssen
- Departments of Health Sciences and Biological Sciences, Faculties of Applied Health Sciences and Mathematics & Science, Brock University, St. Catharines, ON, Canada
| | - David A Mahns
- School of Medicine, Western Sydney University, Penrith, NSW, Australia
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28
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Asseyer S, Cooper G, Paul F. Pain in NMOSD and MOGAD: A Systematic Literature Review of Pathophysiology, Symptoms, and Current Treatment Strategies. Front Neurol 2020; 11:778. [PMID: 33473247 PMCID: PMC7812141 DOI: 10.3389/fneur.2020.00778] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 06/24/2020] [Indexed: 12/18/2022] Open
Abstract
Neuromyelitis optica spectrum disorders (NMOSDs) and myelin oligodendrocyte glycoprotein-antibody-associated disease (MOGAD) are autoimmune inflammatory disorders of the central nervous system (CNS). Pain is highly prevalent and debilitating in NMOSD and MOGAD with a severe impact on quality of life, and there is a critical need for further studies to successfully treat and manage pain in these rare disorders. In NMOSD, pain has a prevalence of over 80%, and pain syndromes include neuropathic, nociceptive, and mixed pain, which can emerge in acute relapse or become chronic during the disease course. The impact of pain in MOGAD has only recently received increased attention, with an estimated prevalence of over 70%. These patients typically experience not only severe headache, retrobulbar pain, and/or pain on eye movement in optic neuritis but also neuropathic and nociceptive pain. Given the high relevance of pain in MOGAD and NMOSD, this article provides a systematic review of the current literature pertaining to pain in both disorders, focusing on the etiology of their respective pain syndromes and their pathophysiological background. Acknowledging the challenge and complexity of diagnosing pain, we also provide a mechanism-based classification of NMOSD- and MOGAD-related pain syndromes and summarize current treatment strategies.
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Affiliation(s)
- Susanna Asseyer
- Experimental and Clinical Research Center, Max Delbrück Center for Molecular Medicine and Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Berlin Institute of Health, Humboldt—Universität zu Berlin, Berlin, Germany
- NeuroCure Clinical Research Center, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Berlin Institute of Health, Humboldt—Universität zu Berlin, Berlin, Germany
| | - Graham Cooper
- Experimental and Clinical Research Center, Max Delbrück Center for Molecular Medicine and Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Berlin Institute of Health, Humboldt—Universität zu Berlin, Berlin, Germany
- NeuroCure Clinical Research Center, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Berlin Institute of Health, Humboldt—Universität zu Berlin, Berlin, Germany
- Einstein Center for Neurosciences, Berlin, Germany
| | - Friedemann Paul
- Experimental and Clinical Research Center, Max Delbrück Center for Molecular Medicine and Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Berlin Institute of Health, Humboldt—Universität zu Berlin, Berlin, Germany
- NeuroCure Clinical Research Center, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Berlin Institute of Health, Humboldt—Universität zu Berlin, Berlin, Germany
- Einstein Center for Neurosciences, Berlin, Germany
- Department of Neurology, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Berlin Institute of Health, Humboldt—Universität zu Berlin, Berlin, Germany
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29
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Driessen AK, Devlin AC, Lundy FT, Martin SL, Sergeant GP, Mazzone SB, McGarvey LP. Perspectives on neuroinflammation contributing to chronic cough. Eur Respir J 2020; 56:13993003.00758-2020. [DOI: 10.1183/13993003.00758-2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 06/30/2020] [Indexed: 02/07/2023]
Abstract
Chronic cough can be a troublesome clinical problem. Current thinking is that increased activity and/or enhanced sensitivity of the peripheral and central neural pathways mediates chronic cough via processes similar to those associated with the development of chronic pain. While inflammation is widely thought to be involved in the development of chronic cough, the true mechanisms causing altered neural activity and sensitisation remain largely unknown. In this back-to-basics perspective article we explore evidence that inflammation in chronic cough may, at least in part, involve neuroinflammation orchestrated by glial cells of the nervous system. We summarise the extensive evidence for the role of both peripheral and central glial cells in chronic pain, and hypothesise that the commonalities between pain and cough pathogenesis and clinical presentation warrant investigations into the neuroinflammatory mechanisms that contribute to chronic cough. We open the debate that glial cells may represent an underappreciated therapeutic target for controlling troublesome cough in disease.
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30
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Donnelly CR, Andriessen AS, Chen G, Wang K, Jiang C, Maixner W, Ji RR. Central Nervous System Targets: Glial Cell Mechanisms in Chronic Pain. Neurotherapeutics 2020; 17:846-860. [PMID: 32820378 PMCID: PMC7609632 DOI: 10.1007/s13311-020-00905-7] [Citation(s) in RCA: 112] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Interactions between central glial cells and neurons in the pain circuitry are critical contributors to the pathogenesis of chronic pain. In the central nervous system (CNS), two major glial cell types predominate: astrocytes and microglia. Injuries or pathological conditions which evoke pain are concurrently associated with the presence of a reactive microglia or astrocyte state, which is characterized by a variety of changes in the morphological, molecular, and functional properties of these cells. In this review, we highlight the changes that reactive microglia and astrocytes undergo following painful injuries and insults and discuss the critical and interactive role these two cell types play in the initiation and maintenance of chronic pain. Additionally, we focus on several crucial mechanisms by which microglia and astrocytes contribute to chronic pain and provide commentary on the therapeutic promise of targeting these pathways. In particular, we discuss how the inflammasome in activated microglia drives maturation and release of key pro-inflammatory cytokines, which drive pain through neuronal- and glial regulations. Moreover, we highlight several potentially-druggable hemichannels and proteases produced by reactive microglia and astrocytes in pain states and discuss how these pathways regulate distinct phases during pain pathogenesis. We also review two emerging areas in chronic pain research: 1) sexually dimorphic glial cell signaling and 2) the role of oligodendrocytes. Finally, we highlight important considerations for potential pain therapeutics targeting glial cell mediators as well as questions that remain in our conceptual understanding of glial cell activation in pain states.
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Affiliation(s)
- Christopher R Donnelly
- Center for Translational Pain Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, NC, 27710, USA.
| | - Amanda S Andriessen
- Center for Translational Pain Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Gang Chen
- Center for Translational Pain Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Kaiyuan Wang
- Center for Translational Pain Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Changyu Jiang
- Center for Translational Pain Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, NC, 27710, USA
| | - William Maixner
- Center for Translational Pain Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Ru-Rong Ji
- Center for Translational Pain Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, NC, 27710, USA.
- Department of Neurobiology, Duke University Medical Center, Durham, NC, 27710, USA.
- Department of Cell Biology, Duke University Medical Center, Durham, NC, 27710, USA.
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31
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Hsieh CT, Lee YJ, Lee JW, Lu S, Tucci MA, Dai X, Ojeda NB, Lee HJ, Fan LW, Tien LT. Interleukin-1 receptor antagonist ameliorates the pain hypersensitivity, spinal inflammation and oxidative stress induced by systemic lipopolysaccharide in neonatal rats. Neurochem Int 2020; 135:104686. [PMID: 31987865 DOI: 10.1016/j.neuint.2020.104686] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Revised: 01/05/2020] [Accepted: 01/13/2020] [Indexed: 02/07/2023]
Abstract
Perinatal inflammation-induced reduction in pain threshold may alter pain sensitivity to hyperalgesia or allodynia which may persist into adulthood. In this study, we investigated the anti-inflammatory protective effect of interleukin-1 receptor antagonist (IL-1ra), an anti-inflammatory cytokine, on systemic lipopolysaccharide (LPS)-induced spinal cord inflammation and oxidative stress, thermal hyperalgesia, and mechanical allodynia in neonatal rats. Intraperitoneal (i.p.) injection of LPS (2 mg/kg) or sterile saline was performed in postnatal day 5 (P5) rat pups, and IL-1ra (100 mg/kg) or saline was administered (i.p.) 5 min after LPS injection. Pain reflex behavior, spinal cord inflammation and oxidative stress were examined 24 h after LPS administration. Systemic LPS exposure led to a reduction of tactile threshold in the von Frey filament tests (mechanical allodynia) and pain response latency in the tail-flick test (thermal hyperalgesia) of P6 neonatal rats. Spinal cord inflammation was indicated by the increased numbers of activated glial cells including microglia (Iba1+) and astrocytes (GFAP+), and elevated levels of pro-inflammatory cytokine interleukin-1β (IL-1β), cyclooxygenase-2 (COX-2), and prostaglandin E2 (PGE2) 24 h after LPS treatment. LPS treatment induced spinal oxidative stress as evidenced by the increase in thiobarbituric acid reactive substances (TBARS) content in the spinal cord. LPS exposure also led to a significant increase in oligodendrocyte lineage population (Olig2+) and mature oligodendrocyte cells (APC+) in the neonatal rat spinal cord. IL-1ra treatment significantly reduced LPS-induced effects including hyperalgesia, allodynia, the increased number of activated microglia, astrocytes and oligodendrocytes, and elevated levels of IL-1β, COX-2, PGE2, and lipid peroxidation (TBARS) in the neonatal rat spinal cord. These data suggest that IL-1ra provides a protective effect against the development of pain hypersensitivity, spinal cord inflammation and oxidative stress in the neonatal rats following LPS exposure, which may be associated with the blockade of LPS-induced pro-inflammatory cytokine IL-1β.
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Affiliation(s)
- Cheng-Ta Hsieh
- School of Medicine, Fu Jen Catholic University, New Taipei City, 24205, Taiwan; Division of Neurosurgery, Department of Surgery, Cathay General Hospital, Taipei, 10630, Taiwan; Department of Chemistry, Fu Jen Catholic University, New Taipei City, 24205, Taiwan; Graduate Institute of Biomedical and Pharmaceutical Science, Fu Jen Catholic University, New Taipei City, 24205, Taiwan
| | - Yih-Jing Lee
- School of Medicine, Fu Jen Catholic University, New Taipei City, 24205, Taiwan
| | - Jonathan W Lee
- Department of Pediatrics, Division of Newborn Medicine, University of Mississippi Medical Center, Jackson, MS, 39216, USA
| | - Silu Lu
- Department of Pediatrics, Division of Newborn Medicine, University of Mississippi Medical Center, Jackson, MS, 39216, USA; Department of Neurology, University of Mississippi Medical Center, Jackson, MS, 39216, USA
| | - Michelle A Tucci
- Department of Anesthesiology, University of Mississippi Medical Center, Jackson, MS, 39216, USA
| | - Xiaoli Dai
- Department of Anesthesiology, University of Mississippi Medical Center, Jackson, MS, 39216, USA
| | - Norma Beatriz Ojeda
- Department of Pediatrics, Division of Newborn Medicine, University of Mississippi Medical Center, Jackson, MS, 39216, USA
| | - Hyun Joon Lee
- Department of Neurology, University of Mississippi Medical Center, Jackson, MS, 39216, USA; Research Services, G.V. (Sonny) Montgomery Veterans Administration Medical Center, Jackson, MS, 39216, USA
| | - Lir-Wan Fan
- Department of Pediatrics, Division of Newborn Medicine, University of Mississippi Medical Center, Jackson, MS, 39216, USA
| | - Lu-Tai Tien
- School of Medicine, Fu Jen Catholic University, New Taipei City, 24205, Taiwan.
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32
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Manion J, Waller MA, Clark T, Massingham JN, Neely GG. Developing Modern Pain Therapies. Front Neurosci 2019; 13:1370. [PMID: 31920521 PMCID: PMC6933609 DOI: 10.3389/fnins.2019.01370] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 12/04/2019] [Indexed: 12/24/2022] Open
Abstract
Chronic pain afflicts as much as 50% of the population at any given time but our methods to address pain remain limited, ineffective and addictive. In order to develop new therapies an understanding of the mechanisms of painful sensitization is essential. We discuss here recent progress in the understanding of mechanisms underlying pain, and how these mechanisms are being targeted to produce modern, specific therapies for pain. Finally, we make recommendations for the next generation of targeted, effective, and safe pain therapies.
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Affiliation(s)
- John Manion
- The Dr. John and Anne Chong Lab for Functional Genomics, Charles Perkins Centre and School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, Australia
| | - Matthew A. Waller
- The Dr. John and Anne Chong Lab for Functional Genomics, Charles Perkins Centre and School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, Australia
| | - Teleri Clark
- The Dr. John and Anne Chong Lab for Functional Genomics, Charles Perkins Centre and School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, Australia
| | - Joshua N. Massingham
- The Dr. John and Anne Chong Lab for Functional Genomics, Charles Perkins Centre and School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, Australia
| | - G. Gregory Neely
- The Dr. John and Anne Chong Lab for Functional Genomics, Charles Perkins Centre and School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, Australia
- Genome Editing Initiative, The University of Sydney, Sydney, NSW, Australia
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33
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Sen MK, Mahns DA, Coorssen JR, Shortland PJ. Behavioural phenotypes in the cuprizone model of central nervous system demyelination. Neurosci Biobehav Rev 2019; 107:23-46. [PMID: 31442519 DOI: 10.1016/j.neubiorev.2019.08.008] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 08/01/2019] [Accepted: 08/12/2019] [Indexed: 12/14/2022]
Abstract
The feeding of cuprizone (CPZ) to animals has been extensively used to model the processes of demyelination and remyelination, with many papers adopting a narrative linked to demyelinating conditions like multiple sclerosis (MS), the aetiology of which is unknown. However, no current animal model faithfully replicates the myriad of symptoms seen in the clinical condition of MS. CPZ ingestion causes mitochondrial and endoplasmic reticulum stress and subsequent apoptosis of oligodendrocytes leads to central nervous system demyelination and glial cell activation. Although there are a wide variety of behavioural tests available for characterizing the functional deficits in animal models of disease, including that of CPZ-induced deficits, they have focused on a narrow subset of outcomes such as motor performance, cognition, and anxiety. The literature has not been systematically reviewed in relation to these or other symptoms associated with clinical MS. This paper reviews these tests and makes recommendations as to which are the most important in order to better understand the role of this model in examining aspects of demyelinating diseases like MS.
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Affiliation(s)
- Monokesh K Sen
- School of Medicine, Western Sydney University, New South Wales, Australia
| | - David A Mahns
- School of Medicine, Western Sydney University, New South Wales, Australia
| | - Jens R Coorssen
- Departments of Health Sciences and Biological Sciences, Faculties of Applied Health Sciences and Mathematics & Science, Brock University, Ontario, Canada.
| | - Peter J Shortland
- Science and Health, Western Sydney University, New South Wales, Australia.
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34
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Moehring F, Halder P, Seal RP, Stucky CL. Uncovering the Cells and Circuits of Touch in Normal and Pathological Settings. Neuron 2019; 100:349-360. [PMID: 30359601 DOI: 10.1016/j.neuron.2018.10.019] [Citation(s) in RCA: 97] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 10/08/2018] [Accepted: 10/09/2018] [Indexed: 01/18/2023]
Abstract
The sense of touch is fundamental as it provides vital, moment-to-moment information about the nature of our physical environment. Primary sensory neurons provide the basis for this sensation in the periphery; however, recent work demonstrates that touch transduction mechanisms also occur upstream of the sensory neurons via non-neuronal cells such as Merkel cells and keratinocytes. Within the spinal cord, deep dorsal horn circuits transmit innocuous touch centrally and also transform touch into pain in the setting of injury. Here non-neuronal cells play a key role in the induction and maintenance of persistent mechanical pain. This review highlights recent advances in our understanding of mechanosensation, including a growing appreciation for the role of non-neuronal cells in both touch and pain.
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Affiliation(s)
- Francie Moehring
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Priyabrata Halder
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; Center for the Neural Basis of Cognition, Pittsburgh, PA 15213, USA
| | - Rebecca P Seal
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; Center for the Neural Basis of Cognition, Pittsburgh, PA 15213, USA; Pittsburgh Center for Pain Research, Pittsburgh, PA 15213, USA
| | - Cheryl L Stucky
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
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35
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Ruiz-Sauri A, Orduña-Valls JM, Blasco-Serra A, Tornero-Tornero C, Cedeño DL, Bejarano-Quisoboni D, Valverde-Navarro AA, Benyamin R, Vallejo R. Glia to neuron ratio in the posterior aspect of the human spinal cord at thoracic segments relevant to spinal cord stimulation. J Anat 2019; 235:997-1006. [PMID: 31347695 DOI: 10.1111/joa.13061] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/21/2019] [Indexed: 12/30/2022] Open
Abstract
Spinal cord stimulation (SCS) applied between T8 and T11 segments has been shown to be effective for the treatment of chronic pain of the lower back and limbs. However, the mechanism of the analgesic effect at these medullary levels remains unclear. Numerous studies relate glial cells with development and maintenance of chronic neuropathic pain. Glial cells are electrically excitable, which makes them a potential therapeutic target using SCS. The aim of this study is to report glia to neuron ratio in thoracic segments relevant to SCS, as well as to characterize the glia cell population at these levels. Dissections from gray and white matter of posterior spinal cord segments (T8, T9, intersection T9/T10, T10 and T11) were obtained from 11 human cadavers for histological analyses. Neuronal bodies and glial cells (microglia, astrocytes and oligodendrocytes) were immunostained, microphotographed and counted using image analysis software. Statistical analyses were carried out to establish significant differences of neuronal and glial populations among the selected segments, between the glial cells in a segment, and glial cells in white and gray matter. Results show that glia to neuron ratio in the posterior gray matter of the human spinal cord within the T8-T11 vertebral region is in the range 11 : 1 to 13 : 1, although not significantly different among vertebral segments. Glia cells are more abundant in gray matter than in white matter, whereas astrocytes and oligodendrocytes are more abundant than microglia (40 : 40 : 20). Interestingly, the population of oligodendrocytes in the T9/T10 intersection is significantly larger than in any other segment. In conclusion, glial cells are the predominant bodies in the posterior gray and white matter of the T8-T11 segments of the human spinal cord. Given the crucial role of glial cells in the development and maintenance of neuropathic pain, and their electrophysiological characteristics, anatomical determination of the ratio of different cell populations in spinal segments commonly exposed to SCS is fundamental to understand fully the biological effects observed with this therapy.
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Affiliation(s)
| | - Jorge M Orduña-Valls
- Department of Anesthesiology, Intensive Care, and Pain Management, Hospital Clínico Universitario de Valencia, Valencia, Spain.,Clínica Indolor, Valencia, Spain
| | - Arantxa Blasco-Serra
- Department of Human Anatomy and Embryology, University of Valencia, Valencia, Spain
| | - Carlos Tornero-Tornero
- Department of Anesthesiology, Intensive Care, and Pain Management, Hospital Clínico Universitario de Valencia, Valencia, Spain.,Clínica Indolor, Valencia, Spain
| | - David L Cedeño
- Basic Science Research, Millennium Pain Center, Bloomington, IL, USA.,Stimgenics, Research and Development, Bloomington, IL, USA.,Department of Psychology, Illinois Wesleyan University, Bloomington, IL, USA
| | - Daniel Bejarano-Quisoboni
- Department of Anesthesiology, Intensive Care, and Pain Management, Hospital Clínico Universitario de Valencia, Valencia, Spain
| | | | - Ramsin Benyamin
- Clínica Indolor, Valencia, Spain.,Basic Science Research, Millennium Pain Center, Bloomington, IL, USA.,Stimgenics, Research and Development, Bloomington, IL, USA.,Department of Psychology, Illinois Wesleyan University, Bloomington, IL, USA
| | - Ricardo Vallejo
- Clínica Indolor, Valencia, Spain.,Basic Science Research, Millennium Pain Center, Bloomington, IL, USA.,Stimgenics, Research and Development, Bloomington, IL, USA.,Department of Psychology, Illinois Wesleyan University, Bloomington, IL, USA
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36
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Luo D, Lin R, Luo L, Li Q, Chen T, Qiu R, Li Y. Glial Plasticity in the Trigeminal Root Entry Zone of a Rat Trigeminal Neuralgia Animal Model. Neurochem Res 2019; 44:1893-1902. [PMID: 31209727 DOI: 10.1007/s11064-019-02824-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 05/12/2019] [Accepted: 06/05/2019] [Indexed: 12/16/2022]
Abstract
The trigeminal root entry zone (TREZ) is the transitional zone of central and peripheral tissue compartments in the trigeminal root. Microvascular compression on the TREZ is the main etiology of most idiopathic trigeminal neuralgia (TN) patients. However, the pathogenesis of TN is still uncertain. To investigate the glial plasticity changes in oligodendrocytes, Schwann cells, astrocytes and microglia/macrophages in the TREZ in TN, immunohistochemical staining and Western blot methods were performed in rats with TN induced by compression injury. The results showed that mechanical compression injury in the trigeminal nerve of the TN rats induced glial plasticity in the TREZ, which dynamically changed the glial interface of the CNS-PNS transitional zone. Additionally, glial fibrillary acidic protein (GFAP)-immunoreactive astrocyte processes significantly proliferated and extended distally from the central region to the peripheral side of the TREZ after nerve compression injury in the TN group. Moreover, the expression of p75 in Schwann cells was upregulated on the peripheral side of the TREZ, and activated Iba-1-immunoreactive microglia/macrophages were observed on both sides of the TREZ. A significantly higher number of Schwann cells, astrocytes and microglia/macrophages were found in the TN group than in the sham operation group (p < 0.05). In conclusion, mechanical compression injury in the TN rats activated various glial cells, including oligodendrocytes, astrocytes, Schwann cells and microglia/macrophages, in the CNS-PNS transitional zone of TREZ. Changes in glial cell plasticity in the TREZ after compression injury might be involved in TN pathogenesis.
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Affiliation(s)
- DaoShu Luo
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, 350122, China.,Key Laboratory of Brain Aging and Neurodegenerative Diseases of Fujian Province, Fuzhou, 350122, China
| | - Ren Lin
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, 350122, China.,Key Laboratory of Brain Aging and Neurodegenerative Diseases of Fujian Province, Fuzhou, 350122, China
| | - LiLi Luo
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, 350122, China
| | - QiuHua Li
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, 350122, China
| | - Ting Chen
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, 350122, China
| | - RongHui Qiu
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, 350122, China
| | - YunQing Li
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, 350122, China. .,Department of Anatomy, Histology and Embryology & K. K. Leung Brain Research Centre, The Fourth Military Medical University, No. 169, West Changle Road, Xi'an, 710032, China.
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37
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Diverse Role of Biological Plasticity in Low Back Pain and Its Impact on Sensorimotor Control of the Spine. J Orthop Sports Phys Ther 2019; 49:389-401. [PMID: 31151376 DOI: 10.2519/jospt.2019.8716] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Pain is complex. It is no longer acceptable to consider pain solely as a peripheral phenomenon involving activation of nociceptive neurons. The contemporary understanding of pain involves consideration of different underlying pain mechanisms and an increasing awareness of plasticity in all of the biological systems. Of note, recent advances in technology and understanding have highlighted the critical importance of neuroimmune interactions, both in the peripheral and central nervous systems, and the interaction between the nervous system and body tissues in the development and maintenance of pain, including low back pain (LBP). Further, the biology of many tissues changes when challenged by pain and injury, as reported in a growing body of literature on the biology of muscle, fat, and connective tissue. These advances in understanding of the complexity of LBP have implications for our understanding of pain and its interaction with the motor system, and may change how we consider motor control in the rehabilitation of LBP. This commentary provides a state-of-the-art overview of plasticity of biology in LBP. The paper is divided into 4 parts that address (1) biology of pain mechanisms, (2) neuroimmune interaction in the central nervous system, (3) neuroimmune interaction in the periphery, and (4) brain and peripheral tissue interaction. Each section considers the implications for clinical management of LBP. J Orthop Sports Phys Ther 2019;49(6):389-401. doi:10.2519/jospt.2019.8716.
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38
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Tang S, Zhou J, Jing H, Liao M, Lin S, Huang Z, Huang T, Zhong J, HanbingWang. Functional roles of lncRNAs and its potential mechanisms in neuropathic pain. Clin Epigenetics 2019; 11:78. [PMID: 31092294 PMCID: PMC6521530 DOI: 10.1186/s13148-019-0671-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 04/25/2019] [Indexed: 12/20/2022] Open
Abstract
Neuropathic pain (NP) is ranked as one of the major forms of chronic pain and emerges as a direct consequence of a lesion or disease affecting the somatosensory nervous system. Despite great advances into the mechanisms of NP, clinical practice is still not satisfactory. Fortunately, progress in elucidating unique features and multiple molecular mechanisms of long non-coding RNAs (lncRNAs) in NP has emerged in the past 10 years, suggesting that novel therapeutic strategies for pain treatment may be proposed. In this review, we will concentrate on recent studies associated with lncRNAs in NP. First, we will describe the alterations of lncRNA expression after spinal cord injury (SCI) and peripheral nerve injury (PNI), and then we illustrate the role of some specific lncRNAs in detail, which may offer new insights into our understanding of the etiology and pathophysiology of NP. Finally, we put special emphasis on the altered expression of lncRNAs in the diverse biological process of NP. Recent advances we summarized above in the development of NP may facilitate translation of these findings from bench to bedside in the future.
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Affiliation(s)
- Simin Tang
- Department of Anesthesiology, The First People's Hospital of Foshan, Foshan, 528000, Guangdong Province, China.,Sun Yet-sen University, Guangzhou, 510000, Guangdong Province, China
| | - Jun Zhou
- Department of Anesthesiology, The First People's Hospital of Foshan, Foshan, 528000, Guangdong Province, China.
| | - Huan Jing
- Department of Anesthesiology, The First People's Hospital of Foshan, Foshan, 528000, Guangdong Province, China.,ZunYi Medical University, ZunYi, 563100, China
| | - Meijuan Liao
- Department of Anesthesiology, The First People's Hospital of Foshan, Foshan, 528000, Guangdong Province, China
| | - Sen Lin
- Department of Anesthesiology, The First People's Hospital of Foshan, Foshan, 528000, Guangdong Province, China
| | - Zhenxing Huang
- Department of Anesthesiology, The First People's Hospital of Foshan, Foshan, 528000, Guangdong Province, China
| | - Teng Huang
- Department of Anesthesiology, The First People's Hospital of Foshan, Foshan, 528000, Guangdong Province, China
| | - Jiying Zhong
- Department of Anesthesiology, The First People's Hospital of Foshan, Foshan, 528000, Guangdong Province, China
| | - HanbingWang
- Department of Anesthesiology, The First People's Hospital of Foshan, Foshan, 528000, Guangdong Province, China
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Skaper SD. Oligodendrocyte precursor cells as a therapeutic target for demyelinating diseases. PROGRESS IN BRAIN RESEARCH 2019; 245:119-144. [PMID: 30961866 DOI: 10.1016/bs.pbr.2019.03.013] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The mechanisms regulating differentiation of multipotent oligodendrocyte progenitor cells (OPCs) into mature oligodendrocytes (OLs) are critical to our understanding of myelination and remyelination. Following acute demyelination in the central nervous system, adult OPCs migrate to the injury site, differentiate into OLs and generate new myelin sheaths. A common feature of regenerative processes is the fact that remyelination efficiency declines with aging and, accounts for the observation that chronic demyelinating diseases like multiple sclerosis (MS) are characterized by an ineffective remyelination. Without doubt, impairment of OPC differentiation is an essential determinant of the aging effects in remyelination. However, spontaneous remyelination is limited in demyelinating diseases such as MS, owing in part to the failure of adult OPCs to differentiate into myelinating OLs. The inability to restore myelin after injury compromises axon integrity and renders them vulnerable to degeneration. Although the genes that regulate the proliferation and differentiation of OPCs during development have been intensively studied, relatively little is known about the molecular signals that regulate the function of adult OPCs after demyelination. Elucidating the mechanisms regulating OPC differentiation are key to identifying pharmacological targets for remyelination-enhancing therapy. This review will discuss OPC biology, myelination, and possible pharmacological targets for promoting the differentiation of OPCs as a strategy to enhance remyelination, including the potential for nanoscale delivery.
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Affiliation(s)
- Stephen D Skaper
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy.
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40
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Fingolimod reduces neuropathic pain behaviors in a mouse model of multiple sclerosis by a sphingosine-1 phosphate receptor 1-dependent inhibition of central sensitization in the dorsal horn. Pain 2019; 159:224-238. [PMID: 29140922 DOI: 10.1097/j.pain.0000000000001106] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Multiple sclerosis (MS) is an autoimmune-inflammatory neurodegenerative disease that is often accompanied by a debilitating neuropathic pain. Disease-modifying agents slow down the progression of multiple sclerosis and prevent relapses, yet it remains unclear if they yield analgesia. We explored the analgesic potential of fingolimod (FTY720), an agonist and/or functional antagonist at the sphingosine-1-phosphate receptor 1 (S1PR1), because it reduces hyperalgesia in models of peripheral inflammatory and neuropathic pain. We used a myelin oligodendrocyte glycoprotein 35 to 55 (MOG35-55) mouse model of experimental autoimmune encephalomyelitis, modified to avoid frank paralysis, and thus, allow for assessment of withdrawal behaviors to somatosensory stimuli. Daily intraperitoneal fingolimod reduced behavioral signs of central neuropathic pain (mechanical and cold hypersensitivity) in a dose-dependent and reversible manner. Both autoimmune encephalomyelitis and fingolimod changed hyperalgesia before modifying motor function, suggesting that pain-related effects and clinical neurological deficits were modulated independently. Fingolimod also reduced cellular markers of central sensitization of neurons in the dorsal horn of the spinal cord: glutamate-evoked Ca signaling and stimulus-evoked phospho-extracellular signal-related kinase ERK (pERK) expression, as well as upregulation of astrocytes (GFAP) and macrophage/microglia (Iba1) immunoreactivity. The antihyperalgesic effects of fingolimod were prevented or reversed by the S1PR1 antagonist W146 (1 mg/kg daily, i.p.) and could be mimicked by either repeated or single injection of the S1PR1-selective agonist SEW2871. Fingolimod did not change spinal membrane S1PR1 content, arguing against a functional antagonist mechanism. We conclude that fingolimod behaves as an S1PR1 agonist to reduce pain in multiple sclerosis by reversing central sensitization of spinal nociceptive neurons.
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41
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Brennan FH, Popovich PG. Emerging targets for reprograming the immune response to promote repair and recovery of function after spinal cord injury. Curr Opin Neurol 2019; 31:334-344. [PMID: 29465433 DOI: 10.1097/wco.0000000000000550] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
PURPOSE OF REVIEW In adult mammals, a traumatic spinal cord injury (SCI) elicits a chronic unregulated neuroinflammatory response accompanied by seemingly paradoxical suppression of systemic immunity. These SCI-induced changes in immune function contribute to poor neurological outcomes and enhanced morbidity or mortality. Nonspecific anti-inflammatory or proinflammatory therapies are ineffective and can even worsen outcomes. Therefore, recent experimental SCI research has advanced the understanding of how neuroimmune cross-talk contributes to spinal cord and systemic pathology. RECENT FINDINGS It is now appreciated that the immune response caused by injury to the brain or spinal cord encompasses heterogeneous elements that can drive events on the spectrum between exacerbating pathology and promoting tissue repair, within the spinal cord and throughout the body. Recent novel discoveries regarding the role and regulation of soluble factors, monocytes/macrophages, microRNAs, lymphocytes and systemic immune function are highlighted in this review. SUMMARY A more nuanced understanding of how the immune system responds and reacts to nervous system injury will present an array of novel therapeutic opportunities for clinical SCI and other forms of neurotrauma.
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Affiliation(s)
- Faith H Brennan
- Center for Brain and Spinal Cord Repair, Department of Neuroscience, The Ohio State University Wexner Medical Center, Columbus, OH, USA
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42
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Regulatory T Cells and Their Derived Cytokine, Interleukin-35, Reduce Pain in Experimental Autoimmune Encephalomyelitis. J Neurosci 2019; 39:2326-2346. [PMID: 30651334 DOI: 10.1523/jneurosci.1815-18.2019] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 12/18/2018] [Accepted: 01/06/2019] [Indexed: 12/21/2022] Open
Abstract
Sensory problems such as neuropathic pain are common and debilitating symptoms in multiple sclerosis (MS), an autoimmune inflammatory disorder of the CNS. Regulatory T (Treg) cells are critical for maintaining immune homeostasis, but their role in MS-associated pain remains unknown. Here, we demonstrate that Treg cell ablation is sufficient to trigger experimental autoimmune encephalomyelitis (EAE) and facial allodynia in immunized female mice. In EAE-induced female mice, adoptive transfer of Treg cells and spinal delivery of the Treg cell cytokine interleukin-35 (IL-35) significantly reduced facial stimulus-evoked pain and spontaneous pain independent of disease severity and increased myelination of the facial nociceptive pathway. The effects of intrathecal IL-35 therapy were Treg-cell dependent and associated with upregulated IL-10 expression in CNS-infiltrating lymphocytes and reduced monocyte infiltration in the trigeminal afferent pathway. We present evidence for a beneficial role of Treg cells and IL-35 in attenuating pain associated with EAE independently of motor symptoms by decreasing neuroinflammation and increasing myelination.SIGNIFICANCE STATEMENT Pain is a highly prevalent symptom affecting the majority of multiple sclerosis (MS) patients and dramatically affects overall health-related quality of life; however, this is a research area that has been largely ignored. Here, we identify for the first time a role for regulatory T (Treg) cells and interleukin-35 (IL-35) in suppressing facial allodynia and facial grimacing in animals with experimental autoimmune encephalomyelitis (EAE). We demonstrate that spinal delivery of Treg cells and IL-35 reduces pain associated with EAE by decreasing neuroinflammation and increasing myelination independently of motor symptoms. These findings increase our understanding of the mechanisms underlying pain in EAE and suggest potential treatment strategies for pain relief in MS.
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43
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Yang Q, Zhou J. Neuroinflammation in the central nervous system: Symphony of glial cells. Glia 2018; 67:1017-1035. [DOI: 10.1002/glia.23571] [Citation(s) in RCA: 160] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 10/26/2018] [Accepted: 11/02/2018] [Indexed: 12/19/2022]
Affiliation(s)
- Qiao‐qiao Yang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology Chinese Academy of Sciences Shanghai China
| | - Jia‐wei Zhou
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology Chinese Academy of Sciences Shanghai China
- University of Chinese Academy of Sciences Shanghai 200031 China
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44
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Andreae LC. FENS-Kavli winter symposium: Review and perspectives on neurological diseases. Eur J Neurosci 2018; 48:1867-1869. [PMID: 30022537 DOI: 10.1111/ejn.14065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 06/19/2018] [Accepted: 07/02/2018] [Indexed: 11/26/2022]
Abstract
The FENS-Kavli winter symposium was held in December, 2017 at the Institute of Science and Technology, Austria. This short report reviews the session on neurological disorders, which included presentations on recent research into chronic pain, demyelinating disease, Alzheimer's disease and autism spectrum disorder. Key advances, emerging themes and major challenges remaining in the field are discussed.
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Affiliation(s)
- Laura C Andreae
- MRC Centre for Neurodevelopmental Disorders, King's College London, London, UK.,Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
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45
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Abstract
Glial cell types were classified less than 100 years ago by del Rio-Hortega. For instance, he correctly surmised that microglia in pathologic central nervous system (CNS) were "voracious monsters" that helped clean the tissue. Although these historical predictions were remarkably accurate, innovative technologies have revealed novel molecular, cellular, and dynamic physiologic aspects of CNS glia. In this review, we integrate recent findings regarding the roles of glia and glial interactions in healthy and injured spinal cord. The three major glial cell types are considered in healthy CNS and after spinal cord injury (SCI). Astrocytes, which in the healthy CNS regulate neurotransmitter and neurovascular dynamics, respond to SCI by becoming reactive and forming a glial scar that limits pathology and plasticity. Microglia, which in the healthy CNS scan for infection/damage, respond to SCI by promoting axon growth and remyelination-but also with hyperactivation and cytotoxic effects. Oligodendrocytes and their precursors, which in healthy tissue speed axon conduction and support axonal function, respond to SCI by differentiating and producing myelin, but are susceptible to death. Thus, post-SCI responses of each glial cell can simultaneously stimulate and stifle repair. Interestingly, potential therapies could also target interactions between these cells. Astrocyte-microglia cross-talk creates a feed-forward loop, so shifting the response of either cell could amplify repair. Astrocytes, microglia, and oligodendrocytes/precursors also influence post-SCI cell survival, differentiation, and remyelination, as well as axon sparing. Therefore, optimizing post-SCI responses of glial cells-and interactions between these CNS cells-could benefit neuroprotection, axon plasticity, and functional recovery.
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Affiliation(s)
- Andrew D Gaudet
- Department of Psychology and Neuroscience, University of Colorado Boulder, Muenzinger D244 | 345 UCB, Boulder, CO, 80309, USA.
- Center for Neuroscience, University of Colorado Boulder, Muenzinger D244 | 345 UCB, Boulder, CO, 80309, USA.
| | - Laura K Fonken
- Division of Pharmacology and Toxicology, University of Texas at Austin, Austin, TX, 78712, USA
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46
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Li T, Wang J, Wang H, Yang Y, Wang S, Huang N, Wang F, Gao X, Niu J, Li Z, Mei F, Xiao L. The deletion of dicer in mature myelinating glial cells causes progressive axonal degeneration but not overt demyelination in adult mice. Glia 2018; 66:1960-1971. [PMID: 29726608 DOI: 10.1002/glia.23450] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 04/05/2018] [Accepted: 04/05/2018] [Indexed: 01/17/2023]
Abstract
Myelinating glial cells (MGCs), oligodendrocytes (OLs) in the central nervous system (CNS) and Schwann cells (SCs) in the peripheral nervous system (PNS), generate myelin sheaths that insulate axons. After myelination is completed in adulthood, MGC functions independent from myelin are required to support axon survival, but the underlying mechanisms are still unclear. Dicer is a key enzyme that is responsible for generating functional micro-RNAs (miRNAs). Despite the importance of Dicer in initiating myelination, the role of Dicer in mature MGCs is still unclear. Here, Dicer was specifically deleted in mature MGCs in 2-month old mice (PLP-CreERT; Dicer fl/fl) by tamoxifen administration. Progressive motor dysfunction was observed in the Dicer conditional knockout mice, which displayed hind limb ataxia at 3 months post recombination that deteriorated into paralysis within 5 months. Massive axonal degeneration/atrophy in peripheral nerves was responsible for this phenomenon, but overt demyelination was not observed in either the CNS or PNS. In contrast to the PNS, signs of axonal degeneration were not observed in the CNS of these animals. We induced a Dicer deletion in oligodendroglia at postnatal day 5 in NG2-CreERT; Dicer fl/fl mice to evaluate whether Dicer expression in OLs is essential for axonal survival. Dicer deletion in oligodendroglia did not cause motor dysfunction at the age of 7 months. Neither axonal atrophy nor demyelination was observed in the CNS. Based on our results, Dicer expression in SCs is required to maintain axon integrity in adult PNS, and Dicer is dispensable for maintaining myelin sheaths in MGCs.
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Affiliation(s)
- Tao Li
- Department of Histology and Embryology, Chongqing Key Laboratory of Neurobiology, Army Medical University (Third Military Medical University), Chongqing, 400038, China
| | - Jingjing Wang
- Department of Histology and Embryology, Chongqing Key Laboratory of Neurobiology, Army Medical University (Third Military Medical University), Chongqing, 400038, China
| | - Hongkai Wang
- Department of Histology and Embryology, Chongqing Key Laboratory of Neurobiology, Army Medical University (Third Military Medical University), Chongqing, 400038, China.,Department of Orthopedics, The Secondary Affiliated Hospital, Guilin Medical University, Guangxi, 541100, China
| | - Yujian Yang
- Department of Histology and Embryology, Chongqing Key Laboratory of Neurobiology, Army Medical University (Third Military Medical University), Chongqing, 400038, China
| | - Shouyu Wang
- Department of Histology and Embryology, Chongqing Key Laboratory of Neurobiology, Army Medical University (Third Military Medical University), Chongqing, 400038, China
| | - Nanxin Huang
- Department of Histology and Embryology, Chongqing Key Laboratory of Neurobiology, Army Medical University (Third Military Medical University), Chongqing, 400038, China
| | - Fei Wang
- Department of Histology and Embryology, Chongqing Key Laboratory of Neurobiology, Army Medical University (Third Military Medical University), Chongqing, 400038, China
| | - Xing Gao
- Department of Histology and Embryology, Chongqing Key Laboratory of Neurobiology, Army Medical University (Third Military Medical University), Chongqing, 400038, China
| | - Jianqin Niu
- Department of Histology and Embryology, Chongqing Key Laboratory of Neurobiology, Army Medical University (Third Military Medical University), Chongqing, 400038, China
| | - Zhifang Li
- Department of Neurology, Affiliated Hospital of Academy of Military Medical Sciences, Beijing, 100071, China
| | - Feng Mei
- Department of Histology and Embryology, Chongqing Key Laboratory of Neurobiology, Army Medical University (Third Military Medical University), Chongqing, 400038, China
| | - Lan Xiao
- Department of Histology and Embryology, Chongqing Key Laboratory of Neurobiology, Army Medical University (Third Military Medical University), Chongqing, 400038, China
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47
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Skaper SD, Facci L, Zusso M, Giusti P. An Inflammation-Centric View of Neurological Disease: Beyond the Neuron. Front Cell Neurosci 2018; 12:72. [PMID: 29618972 PMCID: PMC5871676 DOI: 10.3389/fncel.2018.00072] [Citation(s) in RCA: 275] [Impact Index Per Article: 45.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 02/27/2018] [Indexed: 12/13/2022] Open
Abstract
Inflammation is a complex biological response fundamental to how the body deals with injury and infection to eliminate the initial cause of cell injury and effect repair. Unlike a normally beneficial acute inflammatory response, chronic inflammation can lead to tissue damage and ultimately its destruction, and often results from an inappropriate immune response. Inflammation in the nervous system (“neuroinflammation”), especially when prolonged, can be particularly injurious. While inflammation per se may not cause disease, it contributes importantly to disease pathogenesis across both the peripheral (neuropathic pain, fibromyalgia) and central [e.g., Alzheimer disease, Parkinson disease, multiple sclerosis, motor neuron disease, ischemia and traumatic brain injury, depression, and autism spectrum disorder] nervous systems. The existence of extensive lines of communication between the nervous system and immune system represents a fundamental principle underlying neuroinflammation. Immune cell-derived inflammatory molecules are critical for regulation of host responses to inflammation. Although these mediators can originate from various non-neuronal cells, important sources in the above neuropathologies appear to be microglia and mast cells, together with astrocytes and possibly also oligodendrocytes. Understanding neuroinflammation also requires an appreciation that non-neuronal cell—cell interactions, between both glia and mast cells and glia themselves, are an integral part of the inflammation process. Within this context the mast cell occupies a key niche in orchestrating the inflammatory process, from initiation to prolongation. This review will describe the current state of knowledge concerning the biology of neuroinflammation, emphasizing mast cell-glia and glia-glia interactions, then conclude with a consideration of how a cell's endogenous mechanisms might be leveraged to provide a therapeutic strategy to target neuroinflammation.
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Affiliation(s)
- Stephen D Skaper
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
| | - Laura Facci
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
| | - Morena Zusso
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
| | - Pietro Giusti
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
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Liu CC, Cheng JT, Li TY, Tan PH. Integrated analysis of microRNA and mRNA expression profiles in the rat spinal cord under inflammatory pain conditions. Eur J Neurosci 2017; 46:2713-2728. [DOI: 10.1111/ejn.13745] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 10/06/2017] [Accepted: 10/06/2017] [Indexed: 12/23/2022]
Affiliation(s)
- Chien Cheng Liu
- Department of Biological Sciences; National Sun Yat-sen University; No. 70 Lienhai Rd. Gushan Dist. Kaohsiung City 80424 Taiwan
- Department of Anesthesiology; E-Da Hospital/I-Shou University; Kaohsiung City Taiwan
| | - Jiin Tsuey Cheng
- Department of Biological Sciences; National Sun Yat-sen University; No. 70 Lienhai Rd. Gushan Dist. Kaohsiung City 80424 Taiwan
| | - Tien Yui Li
- Department of Anesthesiology; E-Da Hospital/I-Shou University; Kaohsiung City Taiwan
| | - Ping Heng Tan
- Department of Anesthesiology; Chi Mei Medical Center; No. 901 Zhonghua Rd. Yongkang Dist. Tainan City 71004 Taiwan
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Altered Gene Expression of RNF34 and PACAP Possibly Involved in Mechanism of Exercise-Induced Analgesia for Neuropathic Pain in Rats. Int J Mol Sci 2017; 18:ijms18091962. [PMID: 28902127 PMCID: PMC5618611 DOI: 10.3390/ijms18091962] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 08/29/2017] [Accepted: 09/04/2017] [Indexed: 01/19/2023] Open
Abstract
Despite the availability of several modalities of treatment, including surgery, pharmacological agents, and nerve blocks, neuropathic pain is often unresponsive and sometimes progresses to intractable chronic pain. Although exercise therapy is a candidate for treatment of neuropathic pain, the mechanism underlying its efficacy has not been elucidated. To clarify the molecular mechanism for pain relief induced by exercise, we measured Rnf34 and Pacap mRNA levels in the spinal cord dorsal horn of SNL rats, a model of neuropathic pain. SNL model rats exhibited stable mechanical hyperalgesia for at least 6 weeks. When the rats were forced to exercise on a treadmill, mechanical and thermal hyperalgesia were significantly ameliorated compared with the non-exercise group. Accordingly, gene expression level of Rnf34 and Pacap were also significantly altered in the time course analysis after surgery. These results suggest that exercise therapy possibly involves pain relief in SNL rats by suppressing Rnf34 and Pacap expression in the spinal cord.
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Neuronal-Glial Interactions Maintain Chronic Neuropathic Pain after Spinal Cord Injury. Neural Plast 2017; 2017:2480689. [PMID: 28951789 PMCID: PMC5603132 DOI: 10.1155/2017/2480689] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 06/26/2017] [Accepted: 07/05/2017] [Indexed: 02/01/2023] Open
Abstract
The hyperactive state of sensory neurons in the spinal cord enhances pain transmission. Spinal glial cells have also been implicated in enhanced excitability of spinal dorsal horn neurons, resulting in pain amplification and distortions. Traumatic injuries of the neural system such as spinal cord injury (SCI) induce neuronal hyperactivity and glial activation, causing maladaptive synaptic plasticity in the spinal cord. Recent studies demonstrate that SCI causes persistent glial activation with concomitant neuronal hyperactivity, thus providing the substrate for central neuropathic pain. Hyperactive sensory neurons and activated glial cells increase intracellular and extracellular glutamate, neuropeptides, adenosine triphosphates, proinflammatory cytokines, and reactive oxygen species concentrations, all of which enhance pain transmission. In addition, hyperactive sensory neurons and glial cells overexpress receptors and ion channels that maintain this enhanced pain transmission. Therefore, post-SCI neuronal-glial interactions create maladaptive synaptic circuits and activate intracellular signaling events that permanently contribute to enhanced neuropathic pain. In this review, we describe how hyperactivity of sensory neurons contributes to the maintenance of chronic neuropathic pain via neuronal-glial interactions following SCI.
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