1
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Huang C, van Wijnen AJ, Im HJ. Serotonin Transporter (5-Hydroxytryptamine Transporter, SERT, SLC6A4) and Sodium-dependent Reuptake Inhibitors as Modulators of Pain Behaviors and Analgesic Responses. THE JOURNAL OF PAIN 2024; 25:618-631. [PMID: 37852405 DOI: 10.1016/j.jpain.2023.10.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 10/10/2023] [Accepted: 10/12/2023] [Indexed: 10/20/2023]
Abstract
The serotonin transporter (5-hydroxytryptamine transporter [5-HTT], Serotonin Transporter (SERT), SLC6A4) modulates the activity of serotonin via sodium-dependent reuptake. Given the established importance of serotonin in the control of pain, 5-HTT has received much interest in studies of pain states and as a pharmacological target for serotonin reuptake inhibitors (SRIs). Animal models expressing varying levels of 5-HTT activity show marked differences in pain behaviors and analgesic responses, as well as many serotonin-related physiological effects. In humans, functional nucleotide variations in the SLC6A4 gene, which encodes the serotonin transporter 5-HTT, are associated with certain pathologic pain conditions and differences in responses to pharmacological therapy. These findings collectively reflect the importance of 5-HTT in the intricate physiology and management of pain, as well as the scientific and clinical challenges that need to be considered for the optimization of 5-HTT-related analgesic therapies. PERSPECTIVE: The serotonin transporter 5-HTT/SCL6A4 is sensitive to pharmacological SRIs. Experimental studies on the physiological functions of serotonin, as well as genetic mouse models and clinical phenotype/genotype correlations of nucleotide variation in the human 5-HTT/SCL6A4 gene, provide new insights for the use of SRIs in chronic pain management.
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Affiliation(s)
- Cary Huang
- Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, Illinois; Department of Anesthesiology, NewYork-Presbyterian/Weill Cornell Medical Center, New York, New York.
| | - Andre J van Wijnen
- Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, Illinois; Department of Biochemistry, University of Vermont, Burlington, Vermont.
| | - Hee-Jeong Im
- Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, Illinois; Jesse Brown Veterans Affairs Medical Center (JBVAMC), Chicago, Illinois.
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2
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Kovanur Sampath K, Belcher S, Hales J, Thomson OP, Farrell G, Gisselman AS, Katare R, Tumilty S. The role of micro-RNAs in neuropathic pain-a scoping review. Pain Rep 2023; 8:e1108. [PMID: 37928202 PMCID: PMC10624461 DOI: 10.1097/pr9.0000000000001108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Revised: 09/08/2023] [Accepted: 09/23/2023] [Indexed: 11/07/2023] Open
Abstract
Neuropathic pain can be caused by a lesion or disease of the somatosensory system characterised by pathological neuro-immune alterations. At a molecular level, microRNAs (miRNAs) act as regulators of gene expression orchestrating both immune and neuronal processes. Thus, miRNAs may act as essential modulators of processes for the establishment and maintenance of neuropathic pain. The objective/aims of this scoping review was to explore and chart the literature to identify miRNAs that are dysregulated in neuropathic pain. The following databases were searched from inception to March 2023: PubMed, EBSCO, CINAHL, Cochrane Library, and SCOPUS. Two independent reviewers screened, extracted data, and independently assessed the risk of bias in included studies. The JBI critical appraisal checklist was used for critical appraisal. A narrative synthesis was used to summarise the evidence. Seven studies (total of 384 participants) that met our eligibility criteria were included in this scoping review. Our review has identified different miRNAs that are commonly involved in the chronic neuropathic pain conditions including miR-132, miR-101, and miR-199a. Our review findings further suggest that expression of miRNAs to be significantly associated with increased diabetic disease duration, HbA1C levels, and fibrinogen levels. Our review findings suggest that there is clear association between miRNA expression and chronic neuropathic pain conditions. Therefore, increasing the specificity by selecting a candidate miRNA and identifying its target mRNA is an area of future research.
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Affiliation(s)
- Kesava Kovanur Sampath
- Centre for Health and Social Practice, Waikato Institute of Technology, Hamilton, New Zealand
| | - Suzie Belcher
- Centre for Health and Social Practice, Waikato Institute of Technology, Hamilton, New Zealand
| | - James Hales
- Centre for Health and Social Practice, Waikato Institute of Technology, Hamilton, New Zealand
| | - Oliver P. Thomson
- Research Centre, University College of Osteopathy, London, United Kingdom
| | - Gerard Farrell
- Centre for Health Activity and Rehabilitation Research, School of Physiotherapy, Otago University, Dunedin, New Zealand
| | - Angela Spontelli Gisselman
- Doctor of Physical Therapy Program, Department of Public Health and Community Medicine, School of Medicine, Tufts University, Phoenix, AZ, USA
| | - Rajesh Katare
- Department of Physiology, HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Steve Tumilty
- Centre for Health Activity and Rehabilitation Research, School of Physiotherapy, Otago University, Dunedin, New Zealand
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3
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Ou M, Chen Y, Liu J, Zhang D, Yang Y, Shen J, Miao C, Tang SJ, Liu X, Mulkey DK, Zhu T, Zhou C. Spinal astrocytic MeCP2 regulates Kir4.1 for the maintenance of chronic hyperalgesia in neuropathic pain. Prog Neurobiol 2023; 224:102436. [PMID: 36931588 PMCID: PMC10372923 DOI: 10.1016/j.pneurobio.2023.102436] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 03/06/2023] [Accepted: 03/14/2023] [Indexed: 03/17/2023]
Abstract
Astrocyte activation in the spinal dorsal horn may play an important role in the development of chronic neuropathic pain, but the mechanisms involved in astrocyte activation and their modulatory effects remain unknown. The inward rectifying potassium channel protein 4.1 (Kir4.1) is the most important background K+ channel in astrocytes. However, how Kir4.1 is regulated and contributes to behavioral hyperalgesia in chronic pain is unknown. In this study, single-cell RNA sequencing analysis indicated that the expression levels of both Kir4.1 and Methyl-CpG-binding protein 2 (MeCP2) were decreased in spinal astrocytes after chronic constriction injury (CCI) in a mouse model. Conditional knockout of the Kir4.1 channel in spinal astrocytes led to hyperalgesia, and overexpression of the Kir4.1 channel in spinal cord relieved CCI-induced hyperalgesia. Expression of spinal Kir4.1 after CCI was regulated by MeCP2. Electrophysiological recording in spinal slices showed that knockdown of Kir4.1 significantly up-regulated the excitability of astrocytes and then functionally changed the firing patterns of neurons in dorsal spinal cord. Therefore, targeting spinal Kir4.1 may be a therapeutic approach for hyperalgesia in chronic neuropathic pain.
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Affiliation(s)
- Mengchan Ou
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, China
| | - Yali Chen
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, China; Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, China
| | - Jin Liu
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, China; Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, China
| | - Donghang Zhang
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, China; Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, China
| | - Yaoxin Yang
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, China; Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, China
| | - Jiefei Shen
- Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases and Department of Prosthodontics, West China Stomatology Hospital of Sichuan University, Chengdu 610041, China
| | - Changhong Miao
- Department of Anesthesiology, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Shao-Jun Tang
- Department of Anesthesiology and The Stony Brook University Pain and Analgesia Research Center (SPARC), Stony Brook University, Stony Brook, NY 11794, USA
| | - Xin Liu
- Department of Anesthesiology and The Stony Brook University Pain and Analgesia Research Center (SPARC), Stony Brook University, Stony Brook, NY 11794, USA
| | - Daniel K Mulkey
- Departments of Physiology and Neurobiology, University of Connecticut, Storrs, CT 06269, USA
| | - Tao Zhu
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, China.
| | - Cheng Zhou
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, China.
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4
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Jin J, Kang DH, Jeon J, Lee HG, Kim WM, Yoon MH, Choi JI. Imbalance in the spinal serotonergic pathway induces aggravation of mechanical allodynia and microglial activation in carrageenan inflammation. Korean J Pain 2023; 36:51-59. [PMID: 36581598 PMCID: PMC9812699 DOI: 10.3344/kjp.22297] [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: 08/23/2022] [Revised: 10/17/2022] [Accepted: 10/18/2022] [Indexed: 12/31/2022] Open
Abstract
Background This study investigated the effect of an excess and a deficit of spinal 5-hydroxytryptamine (5-HT) on the mechanical allodynia and neuroglia activation in a rodent pain model of carrageenan inflammation. Methods Male Sprague-Dawley rats were implanted with an intrathecal (i.t.) catheter to administer the drug. To induce an excess or deficit of 5-HT in the spinal cord, animals were given either three i.t. 5-HT injections at 24-hour intervals or a single i.t. injection of 5,7-dihydroxytryptamine (5,7-DHT) before carrageenan inflammation. Mechanical allodynia was measured using the von Frey test for 0-4 hours (early phase) and 24-28 hours (late phase) after carrageenan injection. The changes in the activation of microglia and astrocyte were examined using immunofluorescence of the dorsal horn of the lumbar spinal cord. Results Both an excess and a deficit of spinal 5-HT had no or a minimal effect on the intensity of mechanical allodynia during the early phase but prevented the attenuation of mechanical allodynia during the late phase, which was observed in animals not treated with i.t. 5-HT or 5,7-DHT. Animals with an excess or deficit of 5-HT showed stronger activation of microglia, but not astrocyte, during the early and late phases, than did normal animals. Conclusions Imbalance in the descending 5-HT pathway in the spinal cord could aggravate the mechanical allodynia and enhance the activation of microglia, suggesting that the spinal 5-HT pathway plays an essential role in maintaining the nociceptive processing in balance between facilitation and inhibition in inflammatory pain caused by carrageenan inflammation.
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Affiliation(s)
- Junxiu Jin
- Department of Anesthesiology and Pain Medicine, Chonnam National University Hospital, Chonnam National University Medical School, Gwangju, Korea,BioMedical Sciences Graduate Program (BMSGP), Chonnam National University Medical School, Hwasun, Korea
| | - Dong Ho Kang
- Department of Anesthesiology and Pain Medicine, Chonnam National University Hospital, Chonnam National University Medical School, Gwangju, Korea
| | - Jin Jeon
- Department of Anesthesiology and Pain Medicine, Chonnam National University Hospital, Chonnam National University Medical School, Gwangju, Korea
| | - Hyung Gon Lee
- Department of Anesthesiology and Pain Medicine, Chonnam National University Hospital, Chonnam National University Medical School, Gwangju, Korea,BioMedical Sciences Graduate Program (BMSGP), Chonnam National University Medical School, Hwasun, Korea
| | - Woong Mo Kim
- Department of Anesthesiology and Pain Medicine, Chonnam National University Hospital, Chonnam National University Medical School, Gwangju, Korea,BioMedical Sciences Graduate Program (BMSGP), Chonnam National University Medical School, Hwasun, Korea,Woong Mo Kim, Department of Anesthesiology and Pain Medicine, Chonnam National University Hospital, Chonnam National University Medical School, 42 Jebong-ro, Dong-gu, Gwangju 61469, Korea, Tel: +82-62-220-6894, Fax: +82-62-232-6294, E-mail:
| | - Myung Ha Yoon
- Department of Anesthesiology and Pain Medicine, Chonnam National University Hospital, Chonnam National University Medical School, Gwangju, Korea,BioMedical Sciences Graduate Program (BMSGP), Chonnam National University Medical School, Hwasun, Korea
| | - Jeong Il Choi
- Department of Anesthesiology and Pain Medicine, Chonnam National University Hospital, Chonnam National University Medical School, Gwangju, Korea,BioMedical Sciences Graduate Program (BMSGP), Chonnam National University Medical School, Hwasun, Korea,Correspondence: Jeong Il Choi Department of Anesthesiology and Pain Medicine, Chonnam National University Hospital, Chonnam National University Medical School, 42 Jebong-ro, Dong-gu, Gwangju 61469, Korea, Tel: +82-62-220-6895, Fax: +82-62-232-6294, E-mail:
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5
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Nirvanie-Persaud L, Millis RM. Epigenetics and Pain: New Insights to an Old Problem. Cureus 2022; 14:e29353. [PMID: 36159345 PMCID: PMC9487372 DOI: 10.7759/cureus.29353] [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] [Accepted: 09/19/2022] [Indexed: 11/05/2022] Open
Abstract
Physicians and neuroscientists have long observed that factors such as thoughts, emotions, and expectations can influence the perception of pain. Pain can be described as an unpleasant sensation that causes physical discomfort and emotional distress. It alerts an individual to seek help and is the main complaint that brings individuals to physicians. Though it is associated with probable tissue damage, such damage may be subtle, sometimes involving the release of algesic chemicals, and also influenced by attitudes, beliefs, personality, and social factors. The perception of pain may vary due to a multitude of these factors influencing the ascending sensory impulse propagation to the primary somatosensory cortex. The genetics and epigenetics of pain modulators have been previously studied, but there is a lack of application in the everyday management and treatment of pain due to the paucity of valid evidence-based data. We used the PubMed database as our primary tool for researching current literature on this topic. The MeSH terms used included: gene modification, epigenetics, genes, pain, analgesia, “types of pain, and theories of pain. The results were filtered as follows: publications within the last 10 years, generalized pain studies regarding the biopsychosocial aspect of pain, pertinent genes, and epigenetic modulation of those genes; 52 publications were selected for review. By addressing the external factorial causes and the appropriate application of epigenetic principles which affect pain perception, it is hoped that this review will motivate future advancements in the management of acute and/or chronic pain.
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6
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Akaba Y, Shiohama T, Komaki Y, Seki F, Ortug A, Sawada D, Uchida W, Kamagata K, Shimoji K, Aoki S, Takahashi S, Suzuki T, Natsume J, Takahashi E, Tsujimura K. Comprehensive Volumetric Analysis of Mecp2-Null Mouse Model for Rett Syndrome by T2-Weighted 3D Magnetic Resonance Imaging. Front Neurosci 2022; 16:885335. [PMID: 35620663 PMCID: PMC9127869 DOI: 10.3389/fnins.2022.885335] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 04/20/2022] [Indexed: 01/01/2023] Open
Abstract
Rett syndrome (RTT) is a severe progressive neurodevelopmental disorder characterized by various neurological symptoms. Almost all RTT cases are caused by mutations in the X-linked methyl-CpG-binding protein 2 (MeCP2) gene, and several mouse models have been established to understand the disease. However, the neuroanatomical abnormalities in each brain region of RTT mouse models have not been fully understood. Here, we investigated the global and local neuroanatomy of the Mecp2 gene-deleted RTT model (Mecp2-KO) mouse brain using T2-weighted 3D magnetic resonance imaging with different morphometry to clarify the brain structural abnormalities that are involved in the pathophysiology of RTT. We found a significant reduction in global and almost all local volumes in the brain of Mecp2-KO mice. In addition, a detailed comparative analysis identified specific volume reductions in several brain regions in the Mecp2-deficient brain. Our analysis also revealed that the Mecp2-deficient brain shows changes in hemispheric asymmetry in several brain regions. These findings suggest that MeCP2 affects not only the whole-brain volume but also the region-specific brain structure. Our study provides a framework for neuroanatomical studies of a mouse model of RTT.
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Affiliation(s)
- Yuichi Akaba
- Group of Brain Function and Development, Nagoya University Neuroscience Institute of the Graduate School of Science, Nagoya, Japan
- Research Unit for Developmental Disorders, Institute for Advanced Research, Nagoya University, Nagoya, Japan
- Department of Pediatrics, Asahikawa Medical University, Asahikawa, Japan
| | - Tadashi Shiohama
- Department of Pediatrics, Chiba University Hospital, Chiba, Japan
| | - Yuji Komaki
- Central Institute for Experimental Animals, Kawasaki, Japan
- Department of Physiology, Keio University School of Medicine, Tokyo, Japan
| | - Fumiko Seki
- Central Institute for Experimental Animals, Kawasaki, Japan
- Department of Physiology, Keio University School of Medicine, Tokyo, Japan
| | - Alpen Ortug
- Department of Radiology, Harvard Medical School, Boston, MA, United States
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA, United States
| | - Daisuke Sawada
- Department of Pediatrics, Chiba University Hospital, Chiba, Japan
| | - Wataru Uchida
- Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan
| | - Koji Kamagata
- Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan
| | - Keigo Shimoji
- Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan
- Department of Diagnostic Radiology, Tokyo Metropolitan Geriatric Hospital, Tokyo, Japan
| | - Shigeki Aoki
- Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan
| | - Satoru Takahashi
- Department of Pediatrics, Asahikawa Medical University, Asahikawa, Japan
| | - Takeshi Suzuki
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Jun Natsume
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan
- Department of Developmental Disability Medicine, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Emi Takahashi
- Department of Radiology, Harvard Medical School, Boston, MA, United States
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA, United States
| | - Keita Tsujimura
- Group of Brain Function and Development, Nagoya University Neuroscience Institute of the Graduate School of Science, Nagoya, Japan
- Research Unit for Developmental Disorders, Institute for Advanced Research, Nagoya University, Nagoya, Japan
- Department of Radiology, Harvard Medical School, Boston, MA, United States
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA, United States
- *Correspondence: Keita Tsujimura,
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7
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Spinieli RL, Cazuza RA, Sales AJ, Carolino ROG, Martinez D, Anselmo-Franci J, Tajerian M, Leite-Panissi CR. Persistent inflammatory pain is linked with anxiety-like behaviors, increased blood corticosterone, and reduced global DNA methylation in the rat amygdala. Mol Pain 2022; 18:17448069221121307. [PMID: 35974687 PMCID: PMC9393577 DOI: 10.1177/17448069221121307] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Chronic pain increases the risk of developing anxiety, with limbic areas being likely neurological substrates. Despite high clinical relevance, little is known about the precise behavioral, hormonal, and brain neuroplastic correlates of anxiety in the context of persistent pain. Previous studies have shown that decreased nociceptive thresholds in chronic pain models are paralleled by anxiety-like behavior in rats, but there are conflicting ideas regarding its effects on the stress response and circulating corticosterone levels. Even less is known about the molecular mechanisms through which the brain encodes pain-related anxiety. This study examines how persistent inflammatory pain in a rat model would impact anxiety-like behaviors and corticosterone release, and whether these changes would be reflected in levels of global DNA methylation in brain areas involved in stress regulation. Complete Freund's adjuvant (CFA) or saline was administered in the right hindpaw of adult male Wistar rats. Behavioral testing included the measurement of nociceptive thresholds (digital anesthesiometer), motor function (open field test), and anxiety-like behaviors (elevated plus maze and the dark-light box test). Corticosterone was measured via radioimmunoassay. Global DNA methylation (enzyme immunoassay) as well as DNMT3a levels (western blotting) were quantified in the amygdala, prefrontal cortex, and ventral hippocampus. CFA administration resulted in persistent reduction in nociceptive threshold in the absence of locomotor abnormalities. Increased anxiety-like behaviors were observed in the elevated plus maze and were accompanied by increased blood corticosterone levels 10 days after pain induction. Global DNA methylation was decreased in the amygdala, with no changes in DNMT3a abundance in any of the regions examined. Persistent inflammatory pain promotes anxiety -like behaviors, HPA axis activation, and epigenetic regulation through DNA methylation in the amygdala. These findings describe a molecular mechanism that links pain and stress in a well-characterized rodent model.
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Affiliation(s)
- Richard L Spinieli
- Department of Psychology, School of Philosophy, Science and Literature of Ribeirão Preto, 28133University of São Paulo, São Paulo, Brazil
| | - Rafael Alves Cazuza
- Department of Psychology, School of Philosophy, Science and Literature of Ribeirão Preto, 28133University of São Paulo, São Paulo, Brazil
| | - Amanda Juliana Sales
- Department of Pharmacology, Medical School of Ribeirão Preto, 28133University of São Paulo, São Paulo, Brazil
| | | | - Diana Martinez
- Department of Biomedical Sciences, 363994Cooper Medical School of Rowan University, Camden, NJ, USA
| | - Janete Anselmo-Franci
- Department of Basic and Oral Biology, Dental School of Ribeirão Preto, 28133University of São Paulo, São Paulo, Brazil
| | - Maral Tajerian
- Department of Biology, Queens College, City University of New York, Flushing, NY, USA.,The Graduate Center, City University of New York, New York, NY, USA
| | - Christie Ra Leite-Panissi
- Department of Psychology, School of Philosophy, Science and Literature of Ribeirão Preto, 28133University of São Paulo, São Paulo, Brazil
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Irfan J, Febrianto MR, Sharma A, Rose T, Mahmudzade Y, Di Giovanni S, Nagy I, Torres-Perez JV. DNA Methylation and Non-Coding RNAs during Tissue-Injury Associated Pain. Int J Mol Sci 2022; 23:ijms23020752. [PMID: 35054943 PMCID: PMC8775747 DOI: 10.3390/ijms23020752] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 01/04/2022] [Accepted: 01/07/2022] [Indexed: 02/01/2023] Open
Abstract
While about half of the population experience persistent pain associated with tissue damages during their lifetime, current symptom-based approaches often fail to reduce such pain to a satisfactory level. To provide better patient care, mechanism-based analgesic approaches must be developed, which necessitates a comprehensive understanding of the nociceptive mechanism leading to tissue injury-associated persistent pain. Epigenetic events leading the altered transcription in the nervous system are pivotal in the maintenance of pain in tissue injury. However, the mechanisms through which those events contribute to the persistence of pain are not fully understood. This review provides a summary and critical evaluation of two epigenetic mechanisms, DNA methylation and non-coding RNA expression, on transcriptional modulation in nociceptive pathways during the development of tissue injury-associated pain. We assess the pre-clinical data and their translational implication and evaluate the potential of controlling DNA methylation and non-coding RNA expression as novel analgesic approaches and/or biomarkers of persistent pain.
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Affiliation(s)
- Jahanzaib Irfan
- Nociception Group, Department of Surgery and Cancer, Division of Anaesthetics, Pain Medicine and Intensive Care, Chelsea and Westminster Hospital Campus, Imperial College London, 369 Fulham Road, London SW10 9FJ, UK; (J.I.); (M.R.F.); (A.S.); (T.R.); (Y.M.)
| | - Muhammad Rizki Febrianto
- Nociception Group, Department of Surgery and Cancer, Division of Anaesthetics, Pain Medicine and Intensive Care, Chelsea and Westminster Hospital Campus, Imperial College London, 369 Fulham Road, London SW10 9FJ, UK; (J.I.); (M.R.F.); (A.S.); (T.R.); (Y.M.)
| | - Anju Sharma
- Nociception Group, Department of Surgery and Cancer, Division of Anaesthetics, Pain Medicine and Intensive Care, Chelsea and Westminster Hospital Campus, Imperial College London, 369 Fulham Road, London SW10 9FJ, UK; (J.I.); (M.R.F.); (A.S.); (T.R.); (Y.M.)
| | - Thomas Rose
- Nociception Group, Department of Surgery and Cancer, Division of Anaesthetics, Pain Medicine and Intensive Care, Chelsea and Westminster Hospital Campus, Imperial College London, 369 Fulham Road, London SW10 9FJ, UK; (J.I.); (M.R.F.); (A.S.); (T.R.); (Y.M.)
| | - Yasamin Mahmudzade
- Nociception Group, Department of Surgery and Cancer, Division of Anaesthetics, Pain Medicine and Intensive Care, Chelsea and Westminster Hospital Campus, Imperial College London, 369 Fulham Road, London SW10 9FJ, UK; (J.I.); (M.R.F.); (A.S.); (T.R.); (Y.M.)
| | - Simone Di Giovanni
- Department of Brain Sciences, Division of Neuroscience, Imperial College London, E505, Burlington Danes, Du Cane Road, London W12 ONN, UK;
| | - Istvan Nagy
- Nociception Group, Department of Surgery and Cancer, Division of Anaesthetics, Pain Medicine and Intensive Care, Chelsea and Westminster Hospital Campus, Imperial College London, 369 Fulham Road, London SW10 9FJ, UK; (J.I.); (M.R.F.); (A.S.); (T.R.); (Y.M.)
- Correspondence: (I.N.); (J.V.T.-P.)
| | - Jose Vicente Torres-Perez
- Department of Brain Sciences, Dementia Research Institute, Imperial College London, 86 Wood Ln, London W12 0BZ, UK
- Departament de Biologia Cellular, Biologia Funcional i Antropologia Física, Facultat de Ciències Biològiques, Universitat de València, C/Dr. Moliner 50, 46100 Burjassot, Spain
- Correspondence: (I.N.); (J.V.T.-P.)
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9
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Grannonico M, Brandolini L, Varrassi G, Sebastiani P, Colanardi A, Paladini A, Piroli A, Allegretti M, Di Loreto S. DF3016A induces increased BDNF transcription in ischemic neuroinflammation injury. Brain Res 2020; 1748:147057. [DOI: 10.1016/j.brainres.2020.147057] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 07/27/2020] [Accepted: 08/11/2020] [Indexed: 12/14/2022]
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10
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11
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Peirs C, Dallel R, Todd AJ. Recent advances in our understanding of the organization of dorsal horn neuron populations and their contribution to cutaneous mechanical allodynia. J Neural Transm (Vienna) 2020; 127:505-525. [PMID: 32239353 PMCID: PMC7148279 DOI: 10.1007/s00702-020-02159-1] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 02/10/2020] [Indexed: 02/07/2023]
Abstract
The dorsal horns of the spinal cord and the trigeminal nuclei in the brainstem contain neuron populations that are critical to process sensory information. Neurons in these areas are highly heterogeneous in their morphology, molecular phenotype and intrinsic properties, making it difficult to identify functionally distinct cell populations, and to determine how these are engaged in pathophysiological conditions. There is a growing consensus concerning the classification of neuron populations, based on transcriptomic and transductomic analyses of the dorsal horn. These approaches have led to the discovery of several molecularly defined cell types that have been implicated in cutaneous mechanical allodynia, a highly prevalent and difficult-to-treat symptom of chronic pain, in which touch becomes painful. The main objective of this review is to provide a contemporary view of dorsal horn neuronal populations, and describe recent advances in our understanding of on how they participate in cutaneous mechanical allodynia.
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Affiliation(s)
- Cedric Peirs
- Université Clermont Auvergne, CHU Clermont-Ferrand, Inserm, Neuro-Dol, Clermont-Ferrand, F-63000, France.
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK.
| | - Radhouane Dallel
- Université Clermont Auvergne, CHU Clermont-Ferrand, Inserm, Neuro-Dol, Clermont-Ferrand, F-63000, France
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Andrew J Todd
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK
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12
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Mahurkar-Joshi S, Chang L. Epigenetic Mechanisms in Irritable Bowel Syndrome. Front Psychiatry 2020; 11:805. [PMID: 32922317 PMCID: PMC7456856 DOI: 10.3389/fpsyt.2020.00805] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 07/27/2020] [Indexed: 12/12/2022] Open
Abstract
Irritable bowel syndrome (IBS) is a brain-gut axis disorder characterized by abdominal pain and altered bowel habits. IBS is a multifactorial, stress-sensitive disorder with evidence for familial clustering attributed to genetic or shared environmental factors. However, there are weak genetic associations reported with IBS and a lack of evidence to suggest that major genetic factor(s) contribute to IBS pathophysiology. Studies on animal models of stress, including early life stress, suggest a role for environmental factors, specifically, stress associated with dysregulation of corticotropin releasing factor and hypothalamus-pituitary-adrenal (HPA) axis pathways in the pathophysiology of IBS. Recent evidence suggests that epigenetic mechanisms, which constitute molecular changes not driven by a change in gene sequence, can mediate environmental effects on central and peripheral function. Epigenetic alterations including DNA methylation changes, histone modifications, and differential expression of non-coding RNAs (microRNA [miRNA] and long non-coding RNA) have been associated with several diseases. The objective of this review is to elucidate the molecular factors in the pathophysiology of IBS with an emphasis on epigenetic mechanisms. Emerging evidence for epigenetic changes in IBS includes changes in DNA methylation in animal models of IBS and patients with IBS, and various miRNAs that have been associated with IBS and endophenotypes, such as increased visceral sensitivity and intestinal permeability. DNA methylation, in particular, is an emerging field in the realm of complex diseases and a promising mechanism which can provide important insights into IBS pathogenesis and identify potential targets for treatment.
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Affiliation(s)
- Swapna Mahurkar-Joshi
- G. Oppenheimer Center for Neurobiology of Stress and Resilience, Division of Digestive Diseases, Department of Medicine at UCLA, Los Angeles, CA, United States
| | - Lin Chang
- G. Oppenheimer Center for Neurobiology of Stress and Resilience, Division of Digestive Diseases, Department of Medicine at UCLA, Los Angeles, CA, United States
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Torsney C. Inflammatory pain neural plasticity. CURRENT OPINION IN PHYSIOLOGY 2019. [DOI: 10.1016/j.cophys.2019.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Xie AX, Pan XQ, Meacham RB, Malykhina AP. The Expression of Transcription Factors Mecp2 and CREB Is Modulated in Inflammatory Pelvic Pain. Front Syst Neurosci 2019; 12:69. [PMID: 30687029 PMCID: PMC6336837 DOI: 10.3389/fnsys.2018.00069] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 12/17/2018] [Indexed: 12/30/2022] Open
Abstract
Early activation of transcription factors is one of the epigenetic mechanisms contributing to the induction and maintenance of chronic pain states. Previous studies identified the changes in a number of nociception-related genes, such as calcitonin gene-related peptide (CGRP), substance P (SP), and brain-derived neurotropic factor (BDNF) in the pelvic organs after transient colonic inflammation. The gene and protein expression of these neuropeptides could be modulated by transcription factors Methyl-CpG-binding protein 2 (Mecp2) and cAMP response element-binding protein (CREB). In this study, we aimed to evaluate time-dependent changes in the expression levels of Mecp2 and CREB in the lumbosacral (LS) spinal cord and sensory ganglia after inflammation-induced pelvic pain in rat. Adult Sprague-Dawley rats were treated with 2,4,6-trinitrobenzenesulfonic acid (TNBS) to induce transient colonic inflammation. LS (L6-S2) spinal cord segments and respective dorsal root ganglias (DRGs) were isolated from control and experimental animals at 1, 2, 6, 24 h and 3 days post-TNBS treatment. Immunohistochemical (IHC) labeling and Western blotting experiments were performed to assess the expression of Mecp2, CREB and their phosphorylated forms. Total Mecp2 expression, but not phosphorylated p-Mecp2 (pS421Mecp2) expression was detected in the cells of the spinal dorsal horn under control conditions. Colonic inflammation triggered a significant decrease in the number of Mecp2-expressing neurons in parallel with elevated numbers of pS421Mecp2-expressing cells at 2 h and 6 h post-TNBS. The majority of Mecp2-positive cells (80 ± 6%) co-expressed CREB. TNBS treatment caused a transient up-regulation of CREB-expressing cells at 1 h post-TNBS only. The number of cells expressing phosphorylated CREB (pS133CREB) did not change at 1 h and 2 h post-TNBS, but was down-regulated by three folds at 6 h post-TNBS. Analysis of DRG sections revealed that the number of Mecp2-positive neurons was up-regulated by TNBS treatment, reaching three-fold increase at 2 h post-TNBS, and eight-fold increase at 6 h post-TNBS (p ≤ 0.05 to control). These data showed early changes in Mecp2 and CREB expression in the dorsal horn of the spinal cord and sensory ganglia after colonic inflammation, suggesting a possible contribution Mecp2 and CREB signaling in the development of visceral hyperalgesia and pelvic pain following peripheral inflammation.
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Affiliation(s)
- Alison Xiaoqiao Xie
- Division of Urology, Department of Surgery, School of Medicine, University of Colorado Denver, Aurora, CO, United States
| | - Xiao-Qing Pan
- Division of Urology, Department of Surgery, University of Pennsylvania, Philadelphia, PA, United States
| | - Randall B. Meacham
- Division of Urology, Department of Surgery, School of Medicine, University of Colorado Denver, Aurora, CO, United States
| | - Anna P. Malykhina
- Division of Urology, Department of Surgery, School of Medicine, University of Colorado Denver, Aurora, CO, United States
- *Correspondence: Anna P. Malykhina
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MBD1 Contributes to the Genesis of Acute Pain and Neuropathic Pain by Epigenetic Silencing of Oprm1 and Kcna2 Genes in Primary Sensory Neurons. J Neurosci 2018; 38:9883-9899. [PMID: 30266739 DOI: 10.1523/jneurosci.0880-18.2018] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 09/12/2018] [Accepted: 09/24/2018] [Indexed: 02/06/2023] Open
Abstract
The transmission of normal sensory and/or acute noxious information requires intact expression of pain-associated genes within the pain pathways of nervous system. Expressional changes of these genes after peripheral nerve injury are also critical for neuropathic pain induction and maintenance. Methyl-CpG-binding domain protein 1 (MBD1), an epigenetic repressor, regulates gene transcriptional activity. We report here that MBD1 in the primary sensory neurons of DRG is critical for the genesis of acute pain and neuropathic pain as DRG MBD1-deficient mice exhibit the reduced responses to acute mechanical, heat, cold, and capsaicin stimuli and the blunted nerve injury-induced pain hypersensitivities. Furthermore, DRG overexpression of MBD1 leads to spontaneous pain and evoked pain hypersensitivities in the WT mice and restores acute pain sensitivities in the MBD1-deficient mice. Mechanistically, MDB1 represses Oprm1 and Kcna2 gene expression by recruiting DNA methyltransferase DNMT3a into these two gene promoters in the DRG neurons. DRG MBD1 is likely a key player under the conditions of acute pain and neuropathic pain.SIGNIFICANCE STATEMENT In the present study, we revealed that the mice with deficiency of methyl-CpG-binding domain protein 1 (MBD1), an epigenetic repressor, in the DRG displayed the reduced responses to acute noxious stimuli and the blunted neuropathic pain. We also showed that DRG overexpression of MBD1 produced the hypersensitivities to noxious stimuli in the WT mice and rescued acute pain sensitivities in the MBD1-deficient mice. We have also provided the evidence that MDB1 represses Oprm1 and Kcna2 gene expression by recruiting DNA methyltransferase DNMT3a into these two gene promoters in the DRG neurons. DRG MBD1 may participate in the genesis of acute pain and neuropathic pain likely through regulating DNMT3a-controlled Oprm1 and Kcna2 gene expression in the DRG neurons.
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Kumar R, Jain V, Kushwah N, Dheer A, Mishra KP, Prasad D, Singh SB. Role of DNA Methylation in Hypobaric Hypoxia-Induced Neurodegeneration and Spatial Memory Impairment. Ann Neurosci 2018; 25:191-200. [PMID: 31000957 DOI: 10.1159/000490368] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 05/24/2018] [Indexed: 12/19/2022] Open
Abstract
Hypobaric hypoxia (HH) is a major stress factor that is associated with physiological, biochemical, molecular and genomic alterations. Brain is the organ that reacts sensitively to oxygen deprivation, which leads to oxidative stress and cognitive function impairment. Our previous studies have reported that downregulation of brain derived neurotrophic factor (BDNF) leads to neurodegeneration and memory impairment. The aim of the present study was to investigate the effect of HH exposure on DNA methylation and its regulation in BDNF expression, neurodegeneration and spatial memory impairment. For this purpose, Sprague Dawley rats were exposed to HH at a simulated altitude of 25,000 feet for 14 days. Real-time polymerase chain reaction was used for transcriptional expression of DNA Methyltransferases (DNMTs) including DNMT1, DNMT3a and -DNMT3b, and immunoblotting was used for the translational expression of DNMT1, DNMT3a, DNMT3b, Methyl CpG binding protein 2 (MeCP2), pMeCP2 and BDNF in rat hippocampus. Additionally, neuronal morphology alteration and neurodegeneration in CA1 region of hippocampus were investigated though Cresyl violet (CV) staining and Fluoro-Jade C staining respectively. Results obtained suggested that HH exposure increased the expression of DNMT1 DNMT3b at the mRNA as well as protein level, whereas no significant change was observed in the level of DNMT3a. Furthermore, the level of pMeCP2 and BDNF were significantly decreased; however, the expression level of MeCP2 was significantly increased. The CV and Fluoro-Jade C-positive cells were significantly enhanced in the CA1 region of hippocampus in the HH exposed group as compared to unexposed rats. Thus, the present study concluded that HH decreases neuronal activation by the upregulation of DNA methylation and MeCP2 and decreased the expression of pMeCP2, which result in the downregulation of BDNF. The decreased BDNF expression is associated with neuronal loss and spatial memory impairment. This study highlights that DNMT inhibition could be an important therapeutic target for neurodegenerative diseases.
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Affiliation(s)
- Rahul Kumar
- Neurobiology Division, Defence Institute of Physiology and Allied Science (DIAPS), DRDO, New Delhi, India
| | - Vishal Jain
- Neurophysiology Division, Defence Institute of Physiology and Allied Science (DIAPS), DRDO, New Delhi, India
| | - Neetu Kushwah
- Neurobiology Division, Defence Institute of Physiology and Allied Science (DIAPS), DRDO, New Delhi, India
| | - Aastha Dheer
- Neurobiology Division, Defence Institute of Physiology and Allied Science (DIAPS), DRDO, New Delhi, India
| | - Kamla Prasad Mishra
- Directorate General Life Sciences, Defence research Development Organisation (DRDO), Government of India, DRDO Bhawan, Rajaji Marg, New Delhi, India
| | - Dipti Prasad
- Neurobiology Division, Defence Institute of Physiology and Allied Science (DIAPS), DRDO, New Delhi, India
| | - Shashi Bala Singh
- Directorate General Life Sciences, Defence research Development Organisation (DRDO), Government of India, DRDO Bhawan, Rajaji Marg, New Delhi, India
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17
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Dai Z, Chu H, Ma J, Yan Y, Zhang X, Liang Y. The Regulatory Mechanisms and Therapeutic Potential of MicroRNAs: From Chronic Pain to Morphine Tolerance. Front Mol Neurosci 2018; 11:80. [PMID: 29615865 PMCID: PMC5864932 DOI: 10.3389/fnmol.2018.00080] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 03/01/2018] [Indexed: 12/11/2022] Open
Abstract
Chronic pain, including cancer-related pain, is a pain condition often caused by inflammation or dysfunctional nerves. Chronic pain treatment poses a significant health care challenge, where opioids especially morphine are widely used and patients often develop tolerance over time with aggravated pain. microRNA (miRNA) is known to play important roles in regulating gene expressions in the nervous system to affect neuronal network plasticity related to algogenesis and the developing of morphine tolerance. In this article, we reviewed studies conducted in rodent animal models investigating the mechanisms of miRNAs regulation in chronic pain with different phenotypes and morphine tolerance. In addition, the potential of targeting miRNAs for chronic pain and morphine tolerance treatment is also reviewed. Finally, we point out the directions of the future research in chronic pain and morphine tolerance.
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Affiliation(s)
- Zhao Dai
- Department of Anesthesiology, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Haichen Chu
- Department of Anesthesiology, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Jiahai Ma
- Department of Anesthesiology, The Affiliated Yantai Yuhuangding Hospital, Qingdao University, Qingdao, China
| | - Ying Yan
- Department of Anesthesiology, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Xueying Zhang
- Department of Anesthesiology, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Yongxin Liang
- Department of Anesthesiology, The Affiliated Hospital of Qingdao University, Qingdao, China
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18
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Mamet J, Harris S, Klukinov M, Yeomans DC, Donahue RR, Taylor BK, Eddinger K, Yaksh T, Manning DC. Pharmacology, pharmacokinetics, and metabolism of the DNA-decoy AYX1 for the prevention of acute and chronic post-surgical pain. Mol Pain 2017; 13:1744806917703112. [PMID: 28394696 PMCID: PMC5407669 DOI: 10.1177/1744806917703112] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Background AYX1 is an unmodified DNA-decoy designed to reduce acute post-surgical pain and its chronification with a single intrathecal dose at the time of surgery. AYX1 inhibits the transcription factor early growth response protein 1, which is transiently induced at the time of injury and triggers gene regulation in the dorsal root ganglia and spinal cord that leads to long-term sensitization and pain. This work characterizes the AYX1 dose-response profile in rats and the link to AYX1 pharmacokinetics and metabolism in the cerebrospinal fluid, dorsal root ganglia, and spinal cord. Results The effects of ascending dose-levels of AYX1 on mechanical hypersensitivity were measured in the spared nerve injury model of chronic pain and in a plantar incision model of acute post-surgical pain. AYX1 dose-response profile shows that efficacy rapidly increases from a minimum effective dose of ∼ 0.5 mg to a peak maximum effective dose of ∼ 1 mg. With further dose escalation, the efficacy paradoxically appears to decrease by ∼ 30% and then returns to full efficacy at the maximum feasible dose of ∼ 4 mg. The reduction of efficacy is associated to doses triggering a near-saturation of AYX1 metabolism by nucleases in the cerebrospinal fluid and a paradoxical reduction of AYX1 exposure during the period of early growth response protein 1 induction. This effect is overcome at higher doses that compensate for the effect of metabolism. Discussion AYX1 is a competitive antagonist of early growth response protein 1, which is consistent with the overall increased efficacy observed as dose-levels initially escalate. Chemically, AYX1 is unprotected against degradation by nucleases. The sensitivity to nucleases is reflected in a paradoxical reduction of efficacy in the dose-response curve. Conclusions These findings point to the importance of the nuclease environment of the cerebrospinal fluid to the research and development of AYX1 and other intrathecal nucleotide-based therapeutics.
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Affiliation(s)
| | | | | | | | | | - Brad K Taylor
- 3 Department of Physiology, University of Kentucky, KY, USA
| | - Kelly Eddinger
- 4 Department of Anesthesiology and Pharmacology, University of California, San Diego, CA, USA
| | - Tony Yaksh
- 4 Department of Anesthesiology and Pharmacology, University of California, San Diego, CA, USA
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19
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Gautier A, El Ouaraki H, Bazin N, Salam S, Vodjdani G, Bourgoin S, Pezet S, Bernard JF, Hamon M. Lentiviral vector-driven inhibition of 5-HT synthesis in B3 bulbo-spinal serotonergic projections – Consequences on nociception, inflammatory and neuropathic pain in rats. Exp Neurol 2017; 288:11-24. [DOI: 10.1016/j.expneurol.2016.10.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 10/24/2016] [Accepted: 10/27/2016] [Indexed: 01/19/2023]
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20
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Maiarù M, Tochiki KK, Cox MB, Annan LV, Bell CG, Feng X, Hausch F, Géranton SM. The stress regulator FKBP51 drives chronic pain by modulating spinal glucocorticoid signaling. Sci Transl Med 2016; 8:325ra19. [PMID: 26865567 DOI: 10.1126/scitranslmed.aab3376] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Polymorphisms in FKBP51 are associated with stress-related psychiatric disorders and influence the severity of pain symptoms experienced after trauma. We report that FKBP51 (FK506 binding protein 51) is crucial for the full development and maintenance of long-term pain states. Indeed, FKBP51 knockout mice, as well as mice in which silencing of FKBP51 is restricted to the spinal cord, showed reduced hypersensitivity in several persistent pain models in rodents. FKBP51 deletion did not compromise the detection of acute painful stimuli, a critical protective mechanism. Moreover, the intrathecal administration of the specific FKBP51 inhibitor SAFit2 reduced the severity of an established pain state, confirming the crucial role of spinal FKBP51 in nociceptive processing. Finally, glucocorticoid signaling, which is known to modulate persistent pain states in rodents, was impaired in FKBP51 knockout mice. This finding suggested that FKBP51 regulates chronic pain by modulation of glucocorticoid signaling. Thus, FKBP51 is a central mediator of chronic pain, likely in humans as well as rodents, and is a new pharmacologically tractable target for the treatment of long-term pain states.
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Affiliation(s)
- Maria Maiarù
- Cell and Developmental Biology, University College London (UCL), London WC1E 6BT, UK
| | - Keri K Tochiki
- Cell and Developmental Biology, University College London (UCL), London WC1E 6BT, UK
| | - Marc B Cox
- Border Biomedical Research Center and Department of Biological Sciences, University of Texas at El Paso, El Paso, TX 79902, USA
| | - Leonette V Annan
- Cell and Developmental Biology, University College London (UCL), London WC1E 6BT, UK
| | - Christopher G Bell
- Epigenomic Medicine, Centre for Biological Sciences, Institute of Developmental Sciences, S017 1BJ, and MRC (Medical Research Council) Lifecourse Epidemiology Unit, S016 6YD, University of Southampton, Southampton, UK
| | - Xixi Feng
- Department of Translational Research in Psychiatry, Max Planck Institute of Psychiatry, Munich 80804, Germany
| | - Felix Hausch
- Department of Translational Research in Psychiatry, Max Planck Institute of Psychiatry, Munich 80804, Germany
| | - Sandrine M Géranton
- Cell and Developmental Biology, University College London (UCL), London WC1E 6BT, UK.
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21
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Martirosyan NL, Carotenuto A, Patel AA, Kalani MYS, Yagmurlu K, Lemole GM, Preul MC, Theodore N. The Role of microRNA Markers in the Diagnosis, Treatment, and Outcome Prediction of Spinal Cord Injury. Front Surg 2016; 3:56. [PMID: 27878119 PMCID: PMC5099153 DOI: 10.3389/fsurg.2016.00056] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 09/29/2016] [Indexed: 12/14/2022] Open
Abstract
Spinal cord injury (SCI) is a devastating condition that affects many people worldwide. Treatment focuses on controlling secondary injury cascade and improving regeneration. It has recently been suggested that both the secondary injury cascade and the regenerative process are heavily regulated by microRNAs (miRNAs). The measurement of specific biomarkers could improve our understanding of the disease processes, and thereby provide clinicians with the opportunity to guide treatment and predict clinical outcomes after SCI. A variety of miRNAs exhibit important roles in processes of inflammation, cell death, and regeneration. These miRNAs can be used as diagnostic tools for predicting outcome after SCI. In addition, miRNAs can be used in the treatment of SCI and its symptoms. Significant laboratory and clinical evidence exist to show that miRNAs could be used as robust diagnostic and therapeutic tools for the treatment of patients with SCI. Further clinical studies are warranted to clarify the importance of each subtype of miRNA in SCI management.
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Affiliation(s)
- Nikolay L Martirosyan
- Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, USA; Division of Neurosurgery, University of Arizona, Tucson, AZ, USA
| | | | - Arpan A Patel
- College of Medicine - Phoenix, University of Arizona , Phoenix, AZ , USA
| | - M Yashar S Kalani
- Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center , Phoenix, AZ , USA
| | - Kaan Yagmurlu
- Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center , Phoenix, AZ , USA
| | - G Michael Lemole
- Division of Neurosurgery, University of Arizona , Tucson, AZ , USA
| | - Mark C Preul
- Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center , Phoenix, AZ , USA
| | - Nicholas Theodore
- Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center , Phoenix, AZ , USA
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Tochiki KK, Maiarú M, Norris C, Hunt SP, Géranton SM. The mitogen and stress-activated protein kinase 1 regulates the rapid epigenetic tagging of dorsal horn neurons and nocifensive behaviour. Pain 2016; 157:2594-2604. [PMID: 27482631 PMCID: PMC5065054 DOI: 10.1097/j.pain.0000000000000679] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 07/15/2016] [Accepted: 07/20/2016] [Indexed: 12/15/2022]
Abstract
Phosphorylation of histone H3 at serine 10 (p-H3S10) is a marker of active gene transcription. Using cognitive models of neural plasticity, p-H3S10 was shown to be downstream of extracellular signal-regulated kinase (ERK) signalling in the hippocampus. In this study, we show that nociceptive signalling after peripheral formalin injection increased p-H3S10 expression in the ipsilateral dorsal horn. This increase was maximal 30 minutes after formalin injection and occurred mainly within p-ERK-positive neurons. Spinal p-H3S10-enhanced expression was also observed in neurokinin 1 receptor (NK1R), c-Fos, and Zif268 positive neurons and was inhibited by ablation of serotonergic descending controls. The mitogen and stress-activated protein kinase 1 (MSK1) is downstream of ERK and can induce p-H3S10. We found that, after formalin injection, most phospho-MSK1 (p-MSK1)-positive cells (87% ± 3%) expressed p-ERK and the majority of p-H3S10-positive cells (85% ± 5%) expressed p-MSK1. Inhibition of ERK activity with the MEK inhibitor SL327 reduced formalin-induced p-ERK, p-MSK1, and p-H3S10, demonstrating that spinal p-MSK1 and p-H3S10 were at least partly downstream of ERK signalling. Crucially, pharmacological blockade of spinal MSK1 activity with the novel MSK1 inhibitor SB727651A inhibited formalin-induced spinal p-H3S10 and nocifensive behaviour. These findings are the first to establish the involvement of p-H3S10 and its main kinase, MSK1, in ERK regulation of nociception. Given the general importance of ERK signalling in pain processing, our results suggest that p-H3S10 could play a role in the response to injury.
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Affiliation(s)
- Keri K. Tochiki
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Maria Maiarú
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Caspar Norris
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Stephen P. Hunt
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Sandrine M. Géranton
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
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Liang L, Lutz BM, Bekker A, Tao YX. Epigenetic regulation of chronic pain. Epigenomics 2015; 7:235-45. [PMID: 25942533 DOI: 10.2217/epi.14.75] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Chronic pain arising from peripheral inflammation and tissue or nerve injury is a common clinical symptom. Although intensive research on the neurobiological mechanisms of chronic pain has been carried out during previous decades, this disorder is still poorly managed by current drugs such as opioids and nonsteroidal anti-inflammatory drugs. Inflammation, tissue injury and/or nerve injury-induced changes in gene expression in sensory neurons of the dorsal root ganglion, spinal cord dorsal horn and pain-associated brain regions are thought to participate in chronic pain genesis; however, how these changes occur is still elusive. Epigenetic modifications including DNA methylation and covalent histone modifications control gene expression. Recent studies have shown that peripheral noxious stimulation changes DNA methylation and histone modifications and that these changes may be related to the induction of pain hypersensitivity under chronic pain conditions. This review summarizes the current knowledge and progress in epigenetic research in chronic pain and discusses the potential role of epigenetic modifications as therapeutic antinociceptive targets in this disorder.
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Affiliation(s)
- Lingli Liang
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, 185 S. Orange Avenue, MSB F-548, Newark, NJ 07103, USA
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24
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Hall JD, DeWitte C, Ness TJ, Robbins MT. Serotonin enhances urinary bladder nociceptive processing via a 5-HT3 receptor mechanism. Neurosci Lett 2015; 604:97-102. [PMID: 26247537 DOI: 10.1016/j.neulet.2015.07.048] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 07/30/2015] [Accepted: 07/31/2015] [Indexed: 12/15/2022]
Abstract
Serotonin from the descending pain modulatory pathway is critical to nociceptive processing. Its effects on pain modulation may either be inhibitory or facilitatory, depending on the type of pain and which receptors are involved. Little is known about the role of serotonergic systems in bladder nociceptive processing. These studies examined the effect of systemic administration of the serotonin precursor, 5-hydroxytryptophan (5-HTP), on normal bladder and somatic sensation in rats. ELISA was used to quantify peripheral and central changes in serotonin and its major metabolite following 5-HTP administration, and the potential role of the 5-HT3 receptor on changes in bladder sensation elicited by 5-HTP was investigated. 5-HTP produced bladder hypersensitivity and somatic analgesia. The pro-nociceptive effect of 5-HTP was attenuated by intrathecal, but not systemic, ondansetron. Peripheral increases in serotonin, its metabolism and rate of turnover were detectable within 30min of 5-HTP administration. Significant enhancement of serotonin metabolism was observed centrally. These findings suggest that 5-HTP increases serotonin, which may then affect descending facilitatory systems to produce bladder hypersensitivity via activation of spinal 5-HT3 receptors.
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Affiliation(s)
- Jason D Hall
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, 901 19th Street South, BMR2-Room 202, Birmingham, AL 35294, USA
| | - Cary DeWitte
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, 901 19th Street South, BMR2-Room 202, Birmingham, AL 35294, USA
| | - Timothy J Ness
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, 901 19th Street South, BMR2-Room 202, Birmingham, AL 35294, USA
| | - Meredith T Robbins
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, 901 19th Street South, BMR2-Room 202, Birmingham, AL 35294, USA.
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Zhang R, Huang M, Cao Z, Qi J, Qiu Z, Chiang LY. MeCP2 plays an analgesic role in pain transmission through regulating CREB / miR-132 pathway. Mol Pain 2015; 11:19. [PMID: 25885346 PMCID: PMC4404689 DOI: 10.1186/s12990-015-0015-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 03/24/2015] [Indexed: 12/31/2022] Open
Abstract
Background The Methyl CpG binding protein 2 gene (MeCP2 gene) encodes a critical transcriptional repressor and is widely expressed in mammalian neurons. MeCP2 plays a critical role in neuronal differentiation, neural development, and synaptic plasticity. Mutations and duplications of the human MECP2 gene lead to severe neurodevelopmental disorders, such as Rett syndrome and autism. In this study we investigate the role of MeCP2 in the spinal cord and found that MeCP2 plays an important role as an analgesic mediator in pain circuitry. Findings Experiments using MeCP2 transgenic mice showed that overexpression of MeCP2 weakens both acute mechanical pain and thermal pain, suggesting an analgesic role of MeCP2 in acute pain transduction. We found that through p-CREB/miR-132 signaling cascade is involved in MeCP2-mediated pain transduction. We also examined the role of MeCP2 in chronic pain formation using spared nerve injury (SNI) model. Strikingly, we found that development of neuropathic pain attenuates in MeCP2 transgenic mice comparing to wild type (WT) mice. Conclusions Our study shows that MeCP2 plays an analgesic role in both acute pain transduction and chronic pain formation through regulating CREB-miR-132 pathway. This work provides a potential therapeutic target for neural pathologic pain, and also sheds new lights on the abnormal sensory mechanisms associated with autism spectrum orders.
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Affiliation(s)
- Ran Zhang
- The Key Laboratory of Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, China.
| | - Min Huang
- The Kellogg School of Science and Technology, the Scripps Research Institute, La Jolla, CA, 92037, USA.
| | - Zhijuan Cao
- The Key Laboratory of Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, China.
| | - Jieyu Qi
- The Key Laboratory of Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, China.
| | - Zilong Qiu
- Institute of Neuroscience, Key Laboratory for Primate Neurobiology, Chinese Academy of Sciences, Shanghai, China.
| | - Li-Yang Chiang
- The Key Laboratory of Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, China.
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26
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Descalzi G, Ikegami D, Ushijima T, Nestler EJ, Zachariou V, Narita M. Epigenetic mechanisms of chronic pain. Trends Neurosci 2015; 38:237-46. [PMID: 25765319 DOI: 10.1016/j.tins.2015.02.001] [Citation(s) in RCA: 251] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 02/05/2015] [Accepted: 02/09/2015] [Indexed: 12/12/2022]
Abstract
Neuropathic and inflammatory pain promote a large number of persisting adaptations at the cellular and molecular level, allowing even transient tissue or nerve damage to elicit changes in cells that contribute to the development of chronic pain and associated symptoms. There is evidence that injury-induced changes in chromatin structure drive stable changes in gene expression and neural function, which may cause several symptoms, including allodynia, hyperalgesia, anxiety, and depression. Recent findings on epigenetic changes in the spinal cord and brain during chronic pain may guide fundamental advances in new treatments. Here, we provide a brief overview of epigenetic regulation in the nervous system and then discuss the still-limited literature that directly implicates epigenetic modifications in chronic pain syndromes.
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Affiliation(s)
- Giannina Descalzi
- Fishberg Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Daigo Ikegami
- Department of Pharmacology, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan
| | - Toshikazu Ushijima
- Division of Epigenomics, National Cancer Center Research Institute, 5-1-1, Tsukiji, Chuo-ku, Tokyo, 104-0045, Japan; Life Science Tokyo Advanced Research Center (L-StaR), 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan
| | - Eric J Nestler
- Fishberg Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Venetia Zachariou
- Fishberg Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
| | - Minoru Narita
- Department of Pharmacology, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan; Life Science Tokyo Advanced Research Center (L-StaR), 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan.
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27
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Moloney RD, O'Mahony SM, Dinan TG, Cryan JF. Stress-induced visceral pain: toward animal models of irritable-bowel syndrome and associated comorbidities. Front Psychiatry 2015; 6:15. [PMID: 25762939 PMCID: PMC4329736 DOI: 10.3389/fpsyt.2015.00015] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 01/28/2015] [Indexed: 12/12/2022] Open
Abstract
Visceral pain is a global term used to describe pain originating from the internal organs, which is distinct from somatic pain. It is a hallmark of functional gastrointestinal disorders such as irritable-bowel syndrome (IBS). Currently, the treatment strategies targeting visceral pain are unsatisfactory, with development of novel therapeutics hindered by a lack of detailed knowledge of the underlying mechanisms. Stress has long been implicated in the pathophysiology of visceral pain in both preclinical and clinical studies. Here, we discuss the complex etiology of visceral pain reviewing our current understanding in the context of the role of stress, gender, gut microbiota alterations, and immune functioning. Furthermore, we review the role of glutamate, GABA, and epigenetic mechanisms as possible therapeutic strategies for the treatment of visceral pain for which there is an unmet medical need. Moreover, we discuss the most widely described rodent models used to model visceral pain in the preclinical setting. The theory behind, and application of, animal models is key for both the understanding of underlying mechanisms and design of future therapeutic interventions. Taken together, it is apparent that stress-induced visceral pain and its psychiatric comorbidities, as typified by IBS, has a multifaceted etiology. Moreover, treatment strategies still lag far behind when compared to other pain modalities. The development of novel, effective, and specific therapeutics for the treatment of visceral pain has never been more pertinent.
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Affiliation(s)
- Rachel D Moloney
- Laboratory of Neurogastroenterology, Alimentary Pharmabiotic Centre, Biosciences Institute, University College Cork , Cork , Ireland
| | - Siobhain M O'Mahony
- Laboratory of Neurogastroenterology, Alimentary Pharmabiotic Centre, Biosciences Institute, University College Cork , Cork , Ireland ; Department of Anatomy and Neuroscience, University College Cork , Cork , Ireland
| | - Timothy G Dinan
- Laboratory of Neurogastroenterology, Alimentary Pharmabiotic Centre, Biosciences Institute, University College Cork , Cork , Ireland ; Department of Psychiatry, University College Cork , Cork , Ireland
| | - John F Cryan
- Laboratory of Neurogastroenterology, Alimentary Pharmabiotic Centre, Biosciences Institute, University College Cork , Cork , Ireland ; Department of Anatomy and Neuroscience, University College Cork , Cork , Ireland
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28
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Bai G, Ren K, Dubner R. Epigenetic regulation of persistent pain. Transl Res 2015; 165:177-99. [PMID: 24948399 PMCID: PMC4247805 DOI: 10.1016/j.trsl.2014.05.012] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Revised: 05/19/2014] [Accepted: 05/20/2014] [Indexed: 02/09/2023]
Abstract
Persistent or chronic pain is tightly associated with various environmental changes and linked to abnormal gene expression within cells processing nociceptive signaling. Epigenetic regulation governs gene expression in response to environmental cues. Recent animal model and clinical studies indicate that epigenetic regulation plays an important role in the development or maintenance of persistent pain and possibly the transition of acute pain to chronic pain, thus shedding light in a direction for development of new therapeutics for persistent pain.
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Affiliation(s)
- Guang Bai
- Program in Neuroscience, Department of Neural and Pain Sciences, University of Maryland Dental School, University of Maryland, Baltimore, MD.
| | - Ke Ren
- Program in Neuroscience, Department of Neural and Pain Sciences, University of Maryland Dental School, University of Maryland, Baltimore, MD
| | - Ronald Dubner
- Program in Neuroscience, Department of Neural and Pain Sciences, University of Maryland Dental School, University of Maryland, Baltimore, MD
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29
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Abstract
Pain is an important protective system that alerts organisms to actual or possible tissue damage. However, a variety of pathologies can lead to chronic pain that is no longer beneficial. Lesions or diseases of the somatosensory nervous system cause intractable neuropathic pain that occasionally lasts even after the original pathology subsides. Chronic inflammatory diseases like arthritis are also associated with severe pain. Because conventional analgesics such as non-steroidal anti-inflammatory drugs and opioids have limited efficacy and/or severe adverse events associated with long-term use, chronic pain remains a major problem in clinical practice. Recently, causal roles of microRNAs in chronic pain and their therapeutic potential have been emerging. microRNA expressions are altered not only at the primary origin of pain, but also along the somatosensory pathways. Notably, microRNA expressions are differentially affected depending on the causes of chronic pain. This chapter summarizes current insights into the roles of microRNAs in pain based on the underlying pathologies.
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Affiliation(s)
- Atsushi Sakai
- Department of Pharmacology, Graduate School of Medicine, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo, 113-8602, Japan.
| | - Hidenori Suzuki
- Department of Pharmacology, Graduate School of Medicine, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo, 113-8602, Japan.
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30
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Leith JL, Wilson AW, You HJ, Lumb BM, Donaldson LF. Periaqueductal grey cyclooxygenase-dependent facilitation of C-nociceptive drive and encoding in dorsal horn neurons in the rat. J Physiol 2014; 592:5093-107. [PMID: 25239460 PMCID: PMC4241027 DOI: 10.1113/jphysiol.2014.275909] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Accepted: 09/10/2014] [Indexed: 12/22/2022] Open
Abstract
The experience of pain is strongly affected by descending control systems originating in the brainstem ventrolateral periaqueductal grey (VL-PAG), which control the spinal processing of nociceptive information. A- and C-fibre nociceptors detect noxious stimulation, and have distinct and independent contributions to both the perception of pain quality (fast and slow pain, respectively) and the development of chronic pain. Evidence suggests a separation in the central processing of information arising from A- vs. C-nociceptors; for example, inhibition of the cyclooxygenase-1 (COX-1)-prostaglandin system within the VL-PAG alters spinal nociceptive reflexes evoked by C-nociceptor input in vivo via descending pathways, leaving A-nociceptor-evoked reflexes largely unaffected. As the spinal neuronal mechanisms underlying these different responses remain unknown, we determined the effect of inhibition of VL-PAG COX-1 on dorsal horn wide dynamic-range neurons evoked by C- vs. A-nociceptor activation. Inhibition of VL-PAG COX-1 in anaesthetised rats increased firing thresholds of lamina IV-V wide dynamic-range dorsal horn neurons in response to both A- and C-nociceptor stimulation. Importantly, wide dynamic-range dorsal horn neurons continued to faithfully encode A-nociceptive information, even after VL-PAG COX-1 inhibition, whereas the encoding of C-nociceptor information by wide dynamic-range spinal neurons was significantly disrupted. Dorsal horn neurons with stronger C-nociceptor input were affected by COX-1 inhibition to a greater extent than those with weak C-fibre input. These data show that the gain and contrast of C-nociceptive information processed in individual wide dynamic-range dorsal horn neurons is modulated by prostanergic descending control mechanisms in the VL-PAG.
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Affiliation(s)
- J Lianne Leith
- School of Physiology & Pharmacology, University of Bristol, Bristol, BS8 1TD, UK
| | - Alex W Wilson
- Neurosciences CEDD, GlaxoSmithKline, Harlow, Essex, CM19 5AW, UK
| | - Hao-Jun You
- Center for Biomedical Research on Pain (CBRP), College of Medicine, Xi'an Jiaotong University, Xi'an, 710061, PR China
| | - Bridget M Lumb
- School of Physiology & Pharmacology, University of Bristol, Bristol, BS8 1TD, UK
| | - Lucy F Donaldson
- School of Physiology & Pharmacology, University of Bristol, Bristol, BS8 1TD, UK Arthritis Research UK Pain Centre, School of Life Sciences, QMC, University of Nottingham, Nottingham, NG7 2UH, UK
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31
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Sakai A, Suzuki H. Emerging roles of microRNAs in chronic pain. Neurochem Int 2014; 77:58-67. [DOI: 10.1016/j.neuint.2014.05.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Revised: 05/20/2014] [Accepted: 05/24/2014] [Indexed: 12/19/2022]
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32
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Liu H, Yan WW, Lu XX, Zhang XL, Wei JQ, Wang XY, Wang T, Wu T, Cao J, Shao CJ, Zhou F, Zhang HX, Zhang P, Zang T, Lu XF, Cao JL, Ding HL, Zhang LC. Role of the cerebrospinal fluid-contacting nucleus in the descending inhibition of spinal pain transmission. Exp Neurol 2014; 261:475-85. [DOI: 10.1016/j.expneurol.2014.07.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Revised: 07/19/2014] [Accepted: 07/29/2014] [Indexed: 01/07/2023]
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33
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Li H, Chang Q. Regulation and function of stimulus-induced phosphorylation of MeCP2. FRONTIERS IN BIOLOGY 2014; 9:367-375. [PMID: 25568644 PMCID: PMC4283599 DOI: 10.1007/s11515-014-1330-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
DNA methylation-dependent epigenetic regulation plays important roles in the development and function of the mammalian nervous system. MeCP2 is a key player in recognizing methylated DNA and interpreting the epigenetic information encoded in different DNA methylation patterns. Mutations in the MECP2 gene cause Rett syndrome, a devastating neurological disease that shares many features with autism. One interesting aspect of MeCP2 function is that it can be phosphorylated in response to diverse stimuli. Insights into the regulation and function of MeCP2 phosphorylation will help improve our understanding of how MeCP2 integrates environmental stimuli in neuronal nuclei to generate adaptive responses and may eventually lead to treatments for patients.
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Affiliation(s)
- Hongda Li
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
- Genetics Training Program, University of Wisconsin-Madison, Madison, WI 53705,USA
| | - Qiang Chang
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
- Genetics Training Program, University of Wisconsin-Madison, Madison, WI 53705,USA
- Department of Neurology, University of Wisconsin-Madison, Madison, WI 53705, USA
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34
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Carr FB, Géranton SM, Hunt SP. Descending controls modulate inflammatory joint pain and regulate CXC chemokine and iNOS expression in the dorsal horn. Mol Pain 2014; 10:39. [PMID: 24947159 PMCID: PMC4080690 DOI: 10.1186/1744-8069-10-39] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Accepted: 06/09/2014] [Indexed: 12/19/2022] Open
Abstract
Background Descending control of nociceptive processing, by pathways originating in the rostral ventromedial medulla (RVM) and terminating in the dorsal horn, contributes to behavioural hypersensitivity in a number of pain models. Two facilitatory pathways have been identified and are characterized by serotonin (5-HT) content or expression of the mu opiate receptor. Here we investigated the contribution of these pathways to inflammatory joint pain behaviour and gene expression changes in the dorsal horn. Results Selective lesion of the descending serotonergic (5-HT) pathway by prior intrathecal administration of 5,7-dihydroxytryptamine attenuated hypersensitivity at early time points following ankle injection of CFA. In a separate study ablation of the mu opioid receptor expressing (MOR+) cells of the RVM, by microinjection of the toxin dermorphin-saporin, resulted in a more prolonged attenuation of hypersensitivity post CFA. Microarray analysis was carried out to identify changes in dorsal horn gene expression associated with descending facilitation by the MOR+ pathway at 7d post joint inflammation. This analysis led to the identification of a number of genes including the chemokines Cxcl9 and Cxcl10, their common receptor Cxcr3, and the proinflammatory gene Nos2 (inducible nitric oxide synthase, iNOS). Conclusions These findings demonstrate that joint pain behaviour is dependent in part on descending facilitation via the RVM, and identify a novel pathway driving CXC chemokine and iNOS expression in the dorsal horn.
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Affiliation(s)
| | | | - Stephen P Hunt
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK.
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35
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Guo W, Miyoshi K, Dubner R, Gu M, Li M, Liu J, Yang J, Zou S, Ren K, Noguchi K, Wei F. Spinal 5-HT3 receptors mediate descending facilitation and contribute to behavioral hypersensitivity via a reciprocal neuron-glial signaling cascade. Mol Pain 2014; 10:35. [PMID: 24913307 PMCID: PMC4067691 DOI: 10.1186/1744-8069-10-35] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 05/30/2014] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND It has been recently recognized that the descending serotonin (5-HT) system from the rostral ventromedial medulla (RVM) in the brainstem and the 5-HT3 receptor subtype in the spinal dorsal horn are involved in enhanced descending pain facilitation after tissue and nerve injury. However, the mechanisms underlying the activation of the 5-HT3 receptor and its contribution to facilitation of pain remain unclear. RESULTS In the present study, activation of spinal 5-HT3 receptors by intrathecal injection of a selective 5-HT3 receptor agonist SR 57227 induced spinal glial hyperactivity, neuronal hyperexcitability and pain hypersensitivity in rats. We found that there was neuron-to-microglia signaling via the chemokine fractalkine, microglia to astrocyte signaling via cytokine IL-18, astrocyte to neuronal signaling by IL-1β, and enhanced activation of NMDA receptors in the spinal dorsal horn. Glial hyperactivation in spinal dorsal horn after hindpaw inflammation was also attenuated by molecular depletion of the descending 5-HT system by intra-RVM Tph-2 shRNA interference. CONCLUSIONS These findings offer new insights into the cellular and molecular mechanisms at the spinal level responsible for descending 5-HT-mediated pain facilitation during the development of persistent pain after tissue and nerve injury. New pain therapies should focus on prime targets of descending facilitation-induced glial involvement, and in particular the blocking of intercellular signaling transduction between neurons and glia.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Feng Wei
- Department of Neural and Pain Sciences, Dental School; Program in Neuroscience, University of Maryland, 650 W, Baltimore St, Baltimore, Maryland 21201, USA.
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36
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Hocking MJL. Exploring the central modulation hypothesis: do ancient memory mechanisms underlie the pathophysiology of trigger points? Curr Pain Headache Rep 2013; 17:347. [PMID: 23709237 DOI: 10.1007/s11916-013-0347-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A myofascial trigger point (TrP) is a point of focal tenderness, associated with a taut band of muscle fibers, that can develop in any skeletal muscle. TrPs are a common source of pain and motor dysfunction in humans and other vertebrates. There is no universally accepted pathophysiology to explain the etiology, symptomatology and treatment of TrPs. This article reviews and extends the author's previously published hypothesis for the pathophysiology of TrPs, "Trigger Points and Central Modulation-A New Hypothesis." The author proposes that central nervous system-maintained global changes in α-motoneuron function, resulting from sustained plateau depolarization, rather than a local dysfunction of the motor endplate, underlie the pathogenesis of TrPs.
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Affiliation(s)
- Mark J L Hocking
- Gladesville Veterinary Hospital, 449 Victoria Road, Gladesville, NSW 2111, Australia.
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37
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Kwon M, Altin M, Duenas H, Alev L. The role of descending inhibitory pathways on chronic pain modulation and clinical implications. Pain Pract 2013; 14:656-67. [PMID: 24256177 DOI: 10.1111/papr.12145] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2013] [Accepted: 10/03/2013] [Indexed: 12/12/2022]
Abstract
The treatment and management of chronic pain is a major challenge for clinicians. Chronic pain is often underdiagnosed and undertreated, and there is a lack of awareness of the pathophysiologic mechanisms that contribute to chronic pain. Chronic pain involves peripheral and central sensitization, as well as the alteration of the pain modulatory pathways. Imbalance between the descending facilitatory systems and the descending inhibitory systems is believed to be involved in chronic pain in pathological conditions. A pharmacological treatment that could restore the balance between these 2 pathways by diminishing the descending facilitatory pain pathways and enhancing the descending inhibitory pain pathways would be a valuable therapeutic option for patients with chronic pain. Due to the lack of evidence for pharmacological options that act on descending facilitation pathways, in this review we summarize the role of the descending inhibitory pain pathways in pain perception. This review will focus primarily on monoaminergic descending inhibitory pain pathways and their contribution to the mechanism of chronic pain and several pharmacological treatment options that enhance these pathways to reduce chronic pain. We describe anatomical structures and neurotransmitters of the descending inhibitory pain pathways that are activated in response to nociceptive pain and altered in response to sustained and persistent pain which leads to chronic pain in various pathological conditions.
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Affiliation(s)
- Mikwang Kwon
- Eli Lilly Medical, Quality and Regulatory Affairs Department, Eli Lilly Korea Ltd., Seoul, Korea
| | - Murat Altin
- Eli Lilly Neuroscience, Eli Lilly & Company Turkey, İstanbul, Turkey
| | | | - Levent Alev
- Lilly Research Laboratories Japan, Eli Lilly Japan K.K, Kobe, Japan
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38
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Aira Z, Buesa I, García del Caño G, Bilbao J, Doñate F, Zimmermann M, Azkue JJ. Transient, 5-HT2B receptor–mediated facilitation in neuropathic pain: Up-regulation of PKCγ and engagement of the NMDA receptor in dorsal horn neurons. Pain 2013; 154:1865-1877. [DOI: 10.1016/j.pain.2013.06.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Revised: 06/04/2013] [Accepted: 06/05/2013] [Indexed: 12/22/2022]
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39
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Rahn EJ, Guzman-Karlsson MC, David Sweatt J. Cellular, molecular, and epigenetic mechanisms in non-associative conditioning: implications for pain and memory. Neurobiol Learn Mem 2013; 105:133-50. [PMID: 23796633 DOI: 10.1016/j.nlm.2013.06.008] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 06/10/2013] [Accepted: 06/11/2013] [Indexed: 01/09/2023]
Abstract
Sensitization is a form of non-associative conditioning in which amplification of behavioral responses can occur following presentation of an aversive or noxious stimulus. Understanding the cellular and molecular underpinnings of sensitization has been an overarching theme spanning the field of learning and memory as well as that of pain research. In this review we examine how sensitization, both in the context of learning as well as pain processing, shares evolutionarily conserved behavioral, cellular/synaptic, and epigenetic mechanisms across phyla. First, we characterize the behavioral phenomenon of sensitization both in invertebrates and vertebrates. Particular emphasis is placed on long-term sensitization (LTS) of withdrawal reflexes in Aplysia following aversive stimulation or injury, although additional invertebrate models are also covered. In the context of vertebrates, sensitization of mammalian hyperarousal in a model of post-traumatic stress disorder (PTSD), as well as mammalian models of inflammatory and neuropathic pain is characterized. Second, we investigate the cellular and synaptic mechanisms underlying these behaviors. We focus our discussion on serotonin-mediated long-term facilitation (LTF) and axotomy-mediated long-term hyperexcitability (LTH) in reduced Aplysia systems, as well as mammalian spinal plasticity mechanisms of central sensitization. Third, we explore recent evidence implicating epigenetic mechanisms in learning- and pain-related sensitization. This review illustrates the fundamental and functional overlay of the learning and memory field with the pain field which argues for homologous persistent plasticity mechanisms in response to sensitizing stimuli or injury across phyla.
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Affiliation(s)
- Elizabeth J Rahn
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
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40
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Abstract
MeCP2 (methyl CpG binding protein 2) is a key player in recognizing methylated DNA and interpreting the epigenetic information encoded in different DNA methylation patterns. The functional significance of MeCP2 to the mammalian nervous system is highlighted by the discovery that mutations in the MECP2 gene cause Rett syndrome (RTT), a devastating neurological disease that shares many features with autism. Synaptic scaling is a form of non-Hebbian homeostatic plasticity that allows neurons to regulate overall excitability in response to changes in network neuronal activity levels. While it is known that neuronal activity can induce phosphorylation of MeCP2 and that MeCP2 can regulate synaptic scaling, the molecular link between MeCP2 phosphorylation and synaptic scaling remains undefined. We show here that MeCP2 phosphorylation is specifically required for bicuculline-induced synaptic scaling down in mouse hippocampal neurons and this phenotype is mediated by mGluR5 (metabotropic glutamate receptor 5). Our results reveal an important function of MeCP2 in regulating neuronal homeostasis and may eventually help us understand how MECP2 mutations cause RTT.
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41
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Kynast KL, Russe OQ, Möser CV, Geisslinger G, Niederberger E. Modulation of central nervous system-specific microRNA-124a alters the inflammatory response in the formalin test in mice. Pain 2012; 154:368-376. [PMID: 23318130 DOI: 10.1016/j.pain.2012.11.010] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Revised: 10/02/2012] [Accepted: 11/19/2012] [Indexed: 02/07/2023]
Abstract
microRNAs (miRNAs) are small noncoding RNAs that have been linked to a number of disease-related signal transduction pathways. Several studies indicate that they are also involved in nociception. It is not clear, however, which miRNAs are important and which genes are modulated by miRNA-associated mechanisms. This study focuses on the regulation and function of the central nervous system (CNS)-specific miRNA-124a in the spinal cord of mice in a formalin model of inflammatory nociception. miRNA-124a is constitutively expressed in the spinal cord of mice, particularly in neurons of the dorsal horn. Peripheral noxious stimulation with formalin led to significant down-regulation of its expression. Knock-down of miRNA-124a by intravenous administration of a specific miRNA-124a inhibitor further increased the nociceptive behavior associated with an upregulation of the pain-relevant miRNA-124a target MeCP2 and proinflammatory marker genes. In contrast, administration of a miRNA-124a mimic counteracted these effects and decreased nociception by down-regulation of the target gene. In conclusion, our results indicate that miRNA-124a is involved in inflammatory nociception by regulation of relevant target proteins and might therefore constitute a novel target for anti-inflammatory therapy.
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Affiliation(s)
- Katharina L Kynast
- pharmazentrum frankfurt/ZAFES, Institut für Klinische Pharmakologie, Klinikum der Goethe-Universität Frankfurt, Frankfurt am Main, Germany
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42
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Peters SU, Hundley RJ, Wilson AK, Warren Z, Vehorn A, Carvalho CMB, Lupski JR, Ramocki MB. The behavioral phenotype in MECP2 duplication syndrome: a comparison with idiopathic autism. Autism Res 2012; 6:42-50. [PMID: 23169761 DOI: 10.1002/aur.1262] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Accepted: 10/16/2012] [Indexed: 01/21/2023]
Abstract
Alterations in the X-linked gene MECP2 encoding the methyl-CpG-binding protein 2 have been linked to autism spectrum disorders (ASDs). Most recently, data suggest that overexpression of MECP2 may be related to ASD. To better characterize the relevance of MECP2 overexpression to ASD-related behaviors, we compared the core symptoms of ASD in MECP2 duplication syndrome to nonverbal mental age-matched boys with idiopathic ASD. Within the MECP2 duplication group, we further delineated aspects of the behavioral phenotype and also examined how duplication size and gene content corresponded to clinical severity. We compared ten males with MECP2 duplication syndrome (ages 3-10) with a chronological and mental age-matched sample of nine nonverbal males with idiopathic ASD. Our results indicate that boys with MECP2 duplication syndrome share the core behavioral features of ASD (e.g. social affect, restricted/repetitive behaviors). Direct comparisons of ASD profiles revealed that a majority of boys with MECP2 duplication syndrome are similar to idiopathic ASD; they have impairments in social affect (albeit to a lesser degree than idiopathic ASD) and similar severity in restricted/repetitive behaviors. Nonverbal mental age did not correlate with severity of social impairment or repetitive behaviors. Within the MECP2 duplication group, breakpoint size does not predict differences in clinical severity. In addition to social withdrawal and stereotyped behaviors, we also found that hyposensitivity to pain/temperature are part of the behavioral phenotype of MECP2 duplication syndrome. Our results illustrate that overexpression/increased dosage of MECP2 is related to core features of ASD.
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Affiliation(s)
- Sarika U Peters
- Departments of Pediatrics and Psychiatry, Vanderbilt University, Nashville, TN, USA.
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Peebles KA, Price TJ. Self-injurious behaviour in intellectual disability syndromes: evidence for aberrant pain signalling as a contributing factor. JOURNAL OF INTELLECTUAL DISABILITY RESEARCH : JIDR 2012; 56:441-52. [PMID: 21917053 PMCID: PMC3272540 DOI: 10.1111/j.1365-2788.2011.01484.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
BACKGROUND In most individuals, injury results in activation of peripheral nociceptors (pain-sensing neurons of the peripheral nervous system) and amplification of central nervous system (CNS) pain pathways that serve as a disincentive to continue harmful behaviour; however, this may not be the case in some developmental disorders that cause intellectual disability (ID). Moreover, individuals affected by ID disorders may initiate self-injurious behaviour to address irritating or painful sensations. In normal individuals, a negative feedback loop decreases sensation of pain, which involves descending inhibitory neurons in the CNS that attenuate spinal nociceptive processing. If spinal nociceptive signalling is impaired in these developmental disorders, an exaggerated painful stimulus may be required in order to engage descending anti-nociceptive signals. METHODS Using electronic databases, we conducted a review of publications regarding the incidence of chronic pain or altered pain sensation in ID patients or corresponding preclinical models. RESULTS There is a body of evidence indicating that individuals with fragile X mental retardation and/or Rett syndrome have altered pain sensation. These findings in humans are supported by mechanistic studies using genetically modified mice harbouring mutations consistent with the human disease. Thus, once self-injurious behaviour is initiated, the signal to stop may be missing. Several developmental disorders that cause ID are associated with increased incidence of gastroesophageal reflux disease (GERD), which can cause severe visceral pain. Individuals affected by these disorders who also have GERD may self-injure as a mechanism to engage descending inhibitory circuits to quell visceral pain. In keeping with this hypothesis, pharmacological treatment of GERD has been shown to be effective for reducing self-injurious behaviour in some patients. Hence, multiple lines of evidence suggest aberrant nociceptive processing in developmental disorders that cause ID. CONCLUSIONS There is evidence that pain pathways and pain amplification mechanisms are altered in several preclinical models of developmental disorders that cause ID. We present hypotheses regarding how impaired pain pathways or chronic pain might contribute to self-injurious behaviour. Studies evaluating the relationship between pain and self-injurious behaviour will provide better understanding of the mechanisms underlying self-injurious behaviour in the ID population and may lead to more effective treatments.
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Affiliation(s)
- K A Peebles
- Department of Pharmacology, University of Arizona, Tucson, Arizona 85724, USA
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Tochiki KK, Cunningham J, Hunt SP, Géranton SM. The expression of spinal methyl-CpG-binding protein 2, DNA methyltransferases and histone deacetylases is modulated in persistent pain states. Mol Pain 2012; 8:14. [PMID: 22369085 PMCID: PMC3351747 DOI: 10.1186/1744-8069-8-14] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2011] [Accepted: 02/27/2012] [Indexed: 12/05/2022] Open
Abstract
Background DNA CpG methylation is carried out by DNA methyltransferases and induces chromatin remodeling and gene silencing through a transcription repressor complex comprising the methyl-CpG-binding protein 2 (MeCP2) and a subset of histone deacetylases. Recently, we have found that MeCP2 activity had a crucial role in the pattern of gene expression seen in the superficial dorsal horn rapidly after injection of Complete Freund's Adjuvant (CFA) in the rat ankle joint. The aim of the present study was to analyse the changes in expression of MeCP2, DNA methyltransferases and a subset of histone deacetylases in the superficial dorsal horn during the maintenance phase of persistent pain states. In this process, the cell specific expression of MeCP2 was also investigated. Results Using immunohistochemistry, we found that neurones, oligodendrocytes and astrocytes expressed MeCP2. Microglia, oligodendrocyte precursor cells and Schwann cells never showed any positive stain for MeCP2. Quantitative analyses showed that MeCP2 expression was increased in the superficial dorsal horn 7 days following CFA injection in the ankle joint but decreased 7 days following spared nerve injury. Overall, the expression of DNA methyltransferases and a subset of histone deacetylases followed the same pattern of expression. However, there were no significant changes in the expression of the MeCP2 targets that we had previously shown are regulated in the early time points following CFA injection in the ankle joint. Finally, the expression of MeCP2 was also down regulated in damaged dorsal root ganglion neurones following spared nerve injury. Conclusion Our results strongly suggest that changes in chromatin compaction, regulated by the binding of MeCP2 complexes to methylated DNA, are involved in the modulation of gene expression in the superficial dorsal horn and dorsal root ganglia during the maintenance of persistent pain states.
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Affiliation(s)
- Keri K Tochiki
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
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Abstract
Epigenetic processes, such as histone modifications and DNA methylation, have been associated with many neural functions including synaptic plasticity, learning, and memory. Here, we critically examine emerging evidence linking epigenetic mechanisms to the development or maintenance of chronic pain states. Although in its infancy, research in this area potentially unifies several pathophysiological processes underpinning abnormal pain processing and opens up a different avenue for the development of novel analgesics.
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Affiliation(s)
- Franziska Denk
- King's College London, Wolfson Centre for Age-Related Diseases, Guy's Campus, London SE11UL, UK.
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Abstract
Systemic administration of amphetamine (AMPH) induces phosphorylation of MeCP2 at Ser421 (pMeCP2) in select populations of neurons in the mesolimbocortical brain regions. Because AMPH simultaneously activates multiple monoamine neurotransmitter systems, here we examined the ability of dopamine (DA), serotonin (5-HT), and norepinephrine (NE) to induce pMeCP2. Selective blockade of the DA transporter (DAT) or the 5-HT transporter (SERT), but not the NE transporter (NET), was sufficient to induce pMeCP2 in the CNS. DAT blockade induced pMeCP2 in the prelimbic cortex (PLC) and nucleus accumbens (NAc), whereas SERT blockade induced pMeCP2 only in the NAc. Administration of selective DA and 5-HT receptor agonists was also sufficient to induce pMeCP2; however, the specific combination of DA and 5-HT receptors activated determined the regional- and cell-type specificity of pMeCP2 induction. The D(1)-class DA receptor agonist SKF81297 induced pMeCP2 widely; however, coadministration of the D(2)-class agonist quinpirole restricted the induction of pMeCP2 to GABAergic interneurons of the NAc. Intra-striatal injection of the adenylate cyclase activator forskolin was sufficient to induce pMeCP2 in medium-spiny neurons, suggesting that the combinatorial regulation of cAMP by different classes of DA and 5-HT receptors may contribute to the cell-type specificity of pMeCP2 induction. Consistent with the regulation of pMeCP2 by multiple monoamine neurotransmitters, genetic disruption of any single monoamine transporter in DAT-, SERT-, and NET-knockout mice failed to eliminate AMPH-induced pMeCP2 in the NAc. Together, these studies indicate that combinatorial signaling through DA and 5-HT receptors can regulate the brain region- and cell-type specific pMeCP2 in the CNS.
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Géranton SM. Targeting epigenetic mechanisms for pain relief. Curr Opin Pharmacol 2011; 12:35-41. [PMID: 22056026 DOI: 10.1016/j.coph.2011.10.012] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Accepted: 10/09/2011] [Indexed: 01/06/2023]
Abstract
Epigenetic changes are chemical modifications to chromatin that modulate gene activity without altering the DNA sequence. While research on epigenetics has grown exponentially over the past few years, very few studies have investigated epigenetic mechanisms in relation to pain states. However, epigenetic mechanisms are crucial to memory formation that requires similar synaptic plasticity to pain processing, indicating that they may play a key role in the control of pain states. This article reviews the early evidence suggesting that epigenetic mechanisms are engaged after injury and in chronic pain states, and that drugs used clinically to target the epigenetic machinery for the treatment of cancer might be useful for the management of chronic pain.
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Affiliation(s)
- Sandrine M Géranton
- Department of Cell and Developmental Biology, University College London, London, WC1E 6BT, United Kingdom.
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Wang Y, Liu C, Guo QL, Yan JQ, Zhu XY, Huang CS, Zou WY. Intrathecal 5-azacytidine inhibits global DNA methylation and methyl- CpG-binding protein 2 expression and alleviates neuropathic pain in rats following chronic constriction injury. Brain Res 2011; 1418:64-9. [DOI: 10.1016/j.brainres.2011.08.040] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2011] [Revised: 08/13/2011] [Accepted: 08/16/2011] [Indexed: 11/30/2022]
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Gu M, Miyoshi K, Dubner R, Guo W, Zou S, Ren K, Noguchi K, Wei F. Spinal 5-HT(3) receptor activation induces behavioral hypersensitivity via a neuronal-glial-neuronal signaling cascade. J Neurosci 2011; 31:12823-36. [PMID: 21900561 PMCID: PMC3199304 DOI: 10.1523/jneurosci.1564-11.2011] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Revised: 07/15/2011] [Accepted: 07/18/2011] [Indexed: 01/15/2023] Open
Abstract
Recent studies indicate that the descending serotonin (5-HT) system from the rostral ventromedial medulla (RVM) in the brainstem and the 5-HT(3) receptor subtype in the spinal dorsal horn are involved in enhanced descending pain facilitation after tissue and nerve injury. However, the mechanisms underlying the activation of the 5-HT(3) receptor and its contribution to facilitation of pain remain unclear. In the present study, activation of spinal 5-HT(3) receptor by intrathecal injection of a selective 5-HT(3) receptor agonist, SR57227, induced spinal glial hyperactivity, neuronal hyperexcitability, and pain hypersensitivity in rats. We found that there was neuron-to-microglia signaling via chemokine fractalkine, microglia to astrocyte signaling via the cytokine IL-18, astrocyte to neuronal signaling by IL-1β, and enhanced activation of GluN (NMDA) receptors in the spinal dorsal horn. In addition, exogenous brain-derived neurotrophic factor-induced descending pain facilitation was accompanied by upregulation of CD11b and GFAP expression in the spinal dorsal horn after microinjection in the RVM, and these events were significantly prevented by functional blockade of spinal 5-HT(3) receptors. Enhanced expression of spinal CD11b and GFAP after hindpaw inflammation was also attenuated by molecular depletion of the descending 5-HT system by intra-RVM Tph-2 shRNA interference. Thus, these findings offer new insights into the cellular and molecular mechanisms at the spinal level responsible for descending 5-HT-mediated pain facilitation during the development of persistent pain after tissue and nerve injury. New pain therapies should focus on prime targets of descending facilitation-induced glial involvement, and in particular the blocking of intercellular signaling transduction between neuron and glia.
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Affiliation(s)
- Ming Gu
- Department of Neural and Pain Sciences, Program in Neuroscience, Dental School, University of Maryland, Baltimore, Maryland 21201 and
| | - Kan Miyoshi
- Department of Anatomy and Neuroscience, Institute for Advanced Medical Sciences, Hyogo University, Hyogo 663-8501, Japan
| | - Ronald Dubner
- Department of Neural and Pain Sciences, Program in Neuroscience, Dental School, University of Maryland, Baltimore, Maryland 21201 and
| | - Wei Guo
- Department of Neural and Pain Sciences, Program in Neuroscience, Dental School, University of Maryland, Baltimore, Maryland 21201 and
| | - Shiping Zou
- Department of Neural and Pain Sciences, Program in Neuroscience, Dental School, University of Maryland, Baltimore, Maryland 21201 and
| | - Ke Ren
- Department of Neural and Pain Sciences, Program in Neuroscience, Dental School, University of Maryland, Baltimore, Maryland 21201 and
| | - Koichi Noguchi
- Department of Anatomy and Neuroscience, Institute for Advanced Medical Sciences, Hyogo University, Hyogo 663-8501, Japan
| | - Feng Wei
- Department of Neural and Pain Sciences, Program in Neuroscience, Dental School, University of Maryland, Baltimore, Maryland 21201 and
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Eto K, Kim SK, Nabekura J, Ishibashi H. Taltirelin, a thyrotropin-releasing hormone analog, alleviates mechanical allodynia through activation of descending monoaminergic neurons in persistent inflammatory pain. Brain Res 2011; 1414:50-7. [PMID: 21872219 DOI: 10.1016/j.brainres.2011.07.065] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Revised: 07/23/2011] [Accepted: 07/30/2011] [Indexed: 02/08/2023]
Abstract
Thyrotropin-releasing hormone (TRH) and its analogs have been reported to modulate descending monoaminergic inhibitory neurons, resulting in antinociception. However, it remains unknown whether TRH exerts an antiallodynic effect during persistent pain. Here, we investigated the action of taltirelin, a stable TRH analog, on mechanical allodynia in mice with inflammatory persistent pain induced by an injection of complete Freund's adjuvant into the hindpaw. Systemic administration of 1.0 mg/kg taltirelin markedly reduced mechanical allodynia. This effect was abolished by the 6-hydroxydopamine (6-OHDA)-induced depletion of central noradrenaline. While intraperitoneal injection of the α₁-adrenoceptor antagonist prazosin had no effect, intraperitoneal and intrathecal administration of the α₂-adrenoceptor antagonist yohimbine prevented the antiallodynic action of taltirelin. In addition, DL-p-chlorophenylalanine (PCPA)-induced depletion of serotonin (5-HT) and intraperitoneal and intrathecal injection of the 5-HT(1A) receptor antagonist WAY-100635 blocked the effect of taltirelin on allodynia. These findings suggest that taltirelin alleviates mechanical allodynia in inflammatory persistent pain by modulating the descending noradrenergic and serotonergic neuronal pathways via indirect activation of spinal α₂-adrenergic and 5-HT(1A) receptors.
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Affiliation(s)
- Kei Eto
- Department of Developmental Physiology, National Institute for Physiological Sciences, Okazaki 444-8585, Japan
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