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Tuckey B, Srbely J, Rigney G, Vythilingam M, Shah J. Impaired Lymphatic Drainage and Interstitial Inflammatory Stasis in Chronic Musculoskeletal and Idiopathic Pain Syndromes: Exploring a Novel Mechanism. FRONTIERS IN PAIN RESEARCH 2021; 2:691740. [PMID: 35295453 PMCID: PMC8915610 DOI: 10.3389/fpain.2021.691740] [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: 04/07/2021] [Accepted: 07/19/2021] [Indexed: 11/13/2022] Open
Abstract
A normal functioning lymphatic pump mechanism and unimpaired venous drainage are required for the body to remove inflammatory mediators from the extracellular compartment. Impaired vascular perfusion and/or lymphatic drainage may result in the accumulation of inflammatory substances in the interstitium, creating continuous nociceptor activation and related pathophysiological states including central sensitization and neuroinflammation. We hypothesize that following trauma and/or immune responses, inflammatory mediators may become entrapped in the recently discovered interstitial, pre-lymphatic pathways and/or initial lymphatic vessels. The ensuing interstitial inflammatory stasis is a pathophysiological state, created by specific pro-inflammatory cytokine secretion including tumor necrosis factor alpha, interleukin 6, and interleukin 1b. These cytokines can disable the local lymphatic pump mechanism, impair vascular perfusion via sympathetic activation and, following transforming growth factor beta 1 expression, may lead to additional stasis through direct fascial compression of pre-lymphatic pathways. These mechanisms, when combined with other known pathophysiological processes, enable us to describe a persistent feed-forward loop capable of creating and maintaining chronic pain syndromes. The potential for concomitant visceral and/or vascular dysfunction, initiated and maintained by the same feed-forward inflammatory mechanism, is also described.
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Affiliation(s)
- Brian Tuckey
- Department of Physical Therapy, Tuckey and Associates Physical Therapy, Frederick, MD, United States
| | - John Srbely
- Department of Human Health and Nutritional Sciences, University of Guelph, ON, Canada
| | - Grant Rigney
- Department of Psychiatry, Oxford University, Oxford, United Kingdom
| | - Meena Vythilingam
- Department of Health and Human Services, Center for Health Innovation, Office of the Assistant Secretary for Health, Washington, DC, United States
| | - Jay Shah
- Department of Rehabilitation Medicine, Clinical Center, National Institutes of Health, Bethesda, MD, United States
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Wang Y, Xia YY, Xue M, Jiang Q, Huang Z, Huang C. Electroacupuncture ameliorates mechanical hypersensitivity by down-regulating spinal Janus kinase 2/signal transducer and activation of transcription 3 and interleukin 6 in rats with spared nerve injury. Acupunct Med 2021; 39:358-366. [PMID: 32744065 DOI: 10.1177/0964528420938376] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Evidence shows that the Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) signaling pathway participates in the pathogenesis of neuropathic pain. Our previous study revealed that electroacupuncture (EA) attenuated neuropathic pain via activation of alpha-7 nicotinic acetylcholine receptor (α7nAChR) in the spinal cord. However, whether 2 Hz EA alleviates neuropathic pain by regulating the downstream molecules JAK2/STAT3 has not been fully clarified. METHODS Paw withdrawal threshold (PWT) was used as a marker of mechanical allodynia in rats with spared nerve injury (SNI). After applying 2 Hz EA on day 3, 7, 14 and 21 post-surgery, spinal expression of JAK2, STAT3 and pro-inflammatory cytokine interleukin (IL)-6 was examined using quantitative reverse transcription and real-time polymerase chain reaction (qRT-PCR) and Western blot analysis. Intrathecal injection of the α7nAChR antagonist alpha-bungarotoxin (α-Bgtx) was used to further explore the mechanism underlying the effects of 2 Hz EA on expression of JAK2/STAT3 in SNI rats. RESULTS It was found that levels of spinal STAT3 and IL-6 mRNA, as well as levels of phosphorylated (p)-JAK2, p-STAT3 and IL-6 protein, were markedly increased in SNI rats. 2 Hz EA attenuated the SNI-induced up-regulation of p-JAK2, p-STAT3 and IL-6 expression in the spinal cord. Furthermore, intrathecal injection of α-Bgtx (1.0 μg/kg) not only inhibited the effect of 2 Hz EA on mechanical hypersensitivity but also ameliorated the down-regulation of p-JAK2, p-STAT3 and IL-6 expression induced by 2 Hz EA. CONCLUSION This study revealed that 2 Hz EA attenuated SNI-induced mechanical hypersensitivity and the concomitant up-regulation of spinal JAK2, STAT3 and IL-6 in SNI rats, suggesting that suppression of the JAK2/STAT3 signaling pathway might be the mechanism underlying the therapeutic effect of 2 Hz EA on neuropathic pain.
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Affiliation(s)
- Ying Wang
- Department of Physiology, Gannan Medical University, Ganzhou, P.R. China
| | - Yang-Yang Xia
- Department of Physiology, Gannan Medical University, Ganzhou, P.R. China
| | - Meng Xue
- Department of Physiology, Gannan Medical University, Ganzhou, P.R. China
| | - Qian Jiang
- Department of Physiology, Gannan Medical University, Ganzhou, P.R. China
| | - Zhihua Huang
- Department of Physiology, Gannan Medical University, Ganzhou, P.R. China
- Pain Medicine Research Institute, Gannan Medical University, Ganzhou, P.R. China
| | - Cheng Huang
- Department of Physiology, Gannan Medical University, Ganzhou, P.R. China
- Pain Medicine Research Institute, Gannan Medical University, Ganzhou, P.R. China
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53
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Cao Y. Occlusal disharmony and chronic oro-facial pain: from clinical observation to animal study. J Oral Rehabil 2021; 49:116-124. [PMID: 34333797 DOI: 10.1111/joor.13236] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 06/24/2021] [Accepted: 07/17/2021] [Indexed: 12/21/2022]
Abstract
BACKGROUND Occlusion can be viewed as the most sensitive susceptor of the central nervous system in the oro-facial region. Its inalienable relationships to the temporomandibular joint, the muscles, the stomatognathic system and even the central nervous system are self-evident. Almost all the dental treatments inevitably change the occlusion, potentially or actually, locally or extensively, and immediately or gradually. OBJECTIVE The objective of this study was to present a narrative literature on occlusal disharmony and chronic oro-facial pain. METHODS Literature reviews focusing on clinical studies about the relationship between occlusal disharmony and myofascial oro-facial pain, and related preclinical studies about the animal models of, as well as the peripheral and central mechanisms underlying this condition related to, occlusal disharmony were used as starting point and guidelines to describe the topics mentioned. A search of the PubMed database was performed mainly with the following search terms: "occlusion," "occlusal interference," "occlusal disharmony," "occlusal change," "oro-facial pain" and "myofascial pain." RESULTS Relevant literature from the past 70 years until the present day was meticulously studied. The literature review together with three related characteristic clinical cases revealed an intimate association between occlusal disharmony and chronic oro-facial pain, involving pathological changes, extending from the peripheral tissues to the central nervous system. The patients suffered from psychological distress, sleep disturbance and poor life quality. CONCLUSION Occlusal disharmony-related oro-facial pain is a clinical problem that deserves attention, although there are no universally accepted clinical protocols. The existing literature provides some constructive suggestions, but further research is needed.
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Affiliation(s)
- Ye Cao
- Department of Prosthodontics, Center for Oral and Jaw Functional Diagnosis, Treatment and Research, Peking University School and Hospital of Stomatology, Beijing, China.,Center for TMD & Orofacial Pain, Peking University School and Hospital of Stomatology, Beijing, China.,National Clinical Research Center for Oral Diseases, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Key Laboratory of Digital Stomatology, Beijing, China
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54
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Shinoda M, Imamura Y, Hayashi Y, Noma N, Okada-Ogawa A, Hitomi S, Iwata K. Orofacial Neuropathic Pain-Basic Research and Their Clinical Relevancies. Front Mol Neurosci 2021; 14:691396. [PMID: 34295221 PMCID: PMC8291146 DOI: 10.3389/fnmol.2021.691396] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 05/21/2021] [Indexed: 01/01/2023] Open
Abstract
Trigeminal nerve injury is known to cause severe persistent pain in the orofacial region. This pain is difficult to diagnose and treat. Recently, many animal studies have reported that rewiring of the peripheral and central nervous systems, non-neuronal cell activation, and up- and down-regulation of various molecules in non-neuronal cells are involved in the development of this pain following trigeminal nerve injury. However, there are many unknown mechanisms underlying the persistent orofacial pain associated with trigeminal nerve injury. In this review, we address recent animal data regarding the involvement of various molecules in the communication of neuronal and non-neuronal cells and examine the possible involvement of ascending pathways in processing pathological orofacial pain. We also address the clinical observations of persistent orofacial pain associated with trigeminal nerve injury and clinical approaches to their diagnosis and treatment.
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Affiliation(s)
- Masamichi Shinoda
- Department of Physiology, Nihon University School of Dentistry, Tokyo, Japan
| | - Yoshiki Imamura
- Department of Oral Diagnostic Sciences, Nihon University School of Dentistry, Tokyo, Japan
| | - Yoshinori Hayashi
- Department of Physiology, Nihon University School of Dentistry, Tokyo, Japan
| | - Noboru Noma
- Department of Oral Diagnostic Sciences, Nihon University School of Dentistry, Tokyo, Japan
| | - Akiko Okada-Ogawa
- Department of Oral Diagnostic Sciences, Nihon University School of Dentistry, Tokyo, Japan
| | - Suzuro Hitomi
- Department of Physiology, Nihon University School of Dentistry, Tokyo, Japan
| | - Koichi Iwata
- Department of Physiology, Nihon University School of Dentistry, Tokyo, Japan
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55
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Yeo JH, Kim SJ, Roh DH. Rapamycin reduces orofacial nociceptive responses and microglial p38 mitogen-activated protein kinase phosphorylation in trigeminal nucleus caudalis in mouse orofacial formalin model. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2021; 25:365-374. [PMID: 34187953 PMCID: PMC8255123 DOI: 10.4196/kjpp.2021.25.4.365] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 05/07/2021] [Accepted: 05/21/2021] [Indexed: 12/30/2022]
Abstract
The mammalian target of rapamycin (mTOR) plays a role in various cellular phenomena, including autophagy, cell proliferation, and differentiation. Although recent studies have reported its involvement in nociceptive responses in several pain models, whether mTOR is involved in orofacial pain processing is currently unexplored. This study determined whether rapamycin, an mTOR inhibitor, reduces nociceptive responses and the number of Fos-immunoreactive (Fos-ir) cells in the trigeminal nucleus caudalis (TNC) in a mouse orofacial formalin model. We also examined whether the glial cell expression and phosphorylated p38 (p-p38) mitogen-activated protein kinases (MAPKs) in the TNC are affected by rapamycin. Mice were intraperitoneally given rapamycin (0.1, 0.3, or 1.0 mg/kg); then, 30 min after, 5% formalin (10 µl) was subcutaneously injected into the right upper lip. The rubbing responses with the ipsilateral forepaw or hindpaw were counted for 45 min. High-dose rapamycin (1.0 mg/kg) produced significant antinociceptive effects in both the first and second phases of formalin test. The number of Fos-ir cells in the ipsilateral TNC was also reduced by high-dose rapamycin compared with vehicle-treated animals. Furthermore, the number of p-p38-ir cells the in ipsilateral TNC was significantly decreased in animals treated with high-dose rapamycin; p-p38 expression was co-localized in microglia, but not neurons and astrocytes. Therefore, the mTOR inhibitor, rapamycin, reduces orofacial nociception and Fos expression in the TNC, and its antinociceptive action on orofacial pain may be associated with the inhibition of p-p38 MAPK in the microglia.
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Affiliation(s)
- Ji-Hee Yeo
- Department of Oral Physiology, School of Dentistry, Kyung Hee University, Seoul 02447, Korea
| | - Sol-Ji Kim
- Department of Oral Physiology, School of Dentistry, Kyung Hee University, Seoul 02447, Korea
| | - Dae-Hyun Roh
- Department of Oral Physiology, School of Dentistry, Kyung Hee University, Seoul 02447, Korea
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de Azambuja G, Jorge CO, Gomes BB, Lourenço HR, Simabuco FM, Oliveira-Fusaro MCG. Regular swimming exercise prevented the acute and persistent mechanical muscle hyperalgesia by modulation of macrophages phenotypes and inflammatory cytokines via PPARγ receptors. Brain Behav Immun 2021; 95:462-476. [PMID: 33964434 DOI: 10.1016/j.bbi.2021.05.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 04/09/2021] [Accepted: 05/03/2021] [Indexed: 12/31/2022] Open
Abstract
Physically active individuals are less likely to develop chronic pain, and physical exercise is an established strategy to control inflammatory diseases. Here, we hypothesized that 1) peripheral pro-inflammatory macrophages phenotype contribute to predisposition of the musculoskeletal to chronic pain, and that 2) activation of PPARγ receptors, modulation of macrophage phenotypes and cytokines through physical exercise would prevent persistent muscle pain. We tested these hypotheses using swimming exercise, pharmacological and immunochemical techniques in a rodent model of persistent muscle hyperalgesia. Swimming prevented the persistent mechanical muscle hyperalgesia most likely through activation of PPARγ receptors, as well as activation of PPARγ receptors by 15d-PGJ2 and depletion of muscle macrophages in sedentary animals. Acute and persistent muscle hyperalgesia were characterized by an increase in pro-inflammatory macrophages phenotype, and swimming and the 15d-PGJ2 prevented this increase and increased anti-inflammatory macrophages phenotype. Finally, IL-1β concentration in muscle increased in the acute phase, which was also prevented by PPARγ receptors activation through swimming. Besides, swimming increased muscle concentration of IL-10 in both acute and chronic phases, but only in the persistent phase through PPARγ receptors. Our findings suggest physical exercise activates PPARγ receptors and increases anti-inflammatory responses in the muscle tissue by modulating macrophages phenotypes and cytokines, thereby preventing the establishment of persistent muscle hyperalgesia. These results further highlight the potential of physical exercise to prevent chronic muscle pain.
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Affiliation(s)
- Graciana de Azambuja
- Laboratory of Pain and Inflammation Research, School of Applied Sciences, University of Campinas, Brazil
| | - Carolina O Jorge
- Laboratory of Pain and Inflammation Research, School of Applied Sciences, University of Campinas, Brazil
| | - Beatriz B Gomes
- Laboratory of Pain and Inflammation Research, School of Applied Sciences, University of Campinas, Brazil
| | - Hayla R Lourenço
- Laboratory of Pain and Inflammation Research, School of Applied Sciences, University of Campinas, Brazil
| | - Fernando M Simabuco
- Multidisciplinary Laboratory in Food and Health, School of Applied Sciences, University of Campinas, Brazil
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Henderson-Redmond AN, Crawford LC, Sepulveda DE, Hale DE, Lesperance JJ, Morgan DJ. Sex Differences in Tolerance to Delta-9-Tetrahydrocannabinol in Mice With Cisplatin-Evoked Chronic Neuropathic Pain. Front Mol Biosci 2021; 8:684115. [PMID: 34250019 PMCID: PMC8267820 DOI: 10.3389/fmolb.2021.684115] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 06/02/2021] [Indexed: 12/12/2022] Open
Abstract
Tolerance to the pain-relieving effects of cannabinoids limits the therapeutic potential of these drugs in patients with chronic pain. Recent preclinical research with rodents and clinical studies in humans has suggested important differences between males and females in the development of tolerance to cannabinoids. Our previous work found that male mice expressing a desensitization resistant form (S426A/S430A) of the type 1 cannabinoid receptor (CB1R) show delayed tolerance and increased sensitivity to the antinociceptive effects of delta-9-tetrahydrocannabinol (∆9-THC). Sex differences in tolerance have been reported in rodent models with females acquiring tolerance to ∆9-THC faster than males. However, it remains unknown whether the S426A/S430A mutation alters analgesic tolerance to ∆9-THC in mice with chemotherapy-evoked chronic neuropathic pain, and also whether this tolerance might be different between males and females. Male and female S426A/S430A mutant and wild-type littermates were made neuropathic using four once-weekly injections of 5 mg/kg cisplatin and subsequently assessed for tolerance to the anti-allodynic effects of 6 and/or 10 mg/kg ∆9-THC. Females acquired tolerance to the anti-allodynic effects of both 6 and 10 mg/kg ∆9-THC faster than males. In contrast, the S426A/S430A mutation did not alter tolerance to ∆9-THC in either male or female mice. The anti-allodynic effects of ∆9-THC were blocked following pretreatment with the CB1R antagonist, rimonabant, and partially blocked following pretreatment with the CB2R inverse agonist, SR144528. Our results show that disruption of the GRK/β-arrestin-2 pathway of desensitization did not affect sensitivity and/or tolerance to ∆9-THC in a chronic pain model of neuropathy.
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Affiliation(s)
- Angela N Henderson-Redmond
- Department of Biomedical Sciences, Marshall University, Huntington, WV, United States.,Department of Pharmacology, Penn State University College of Medicine, Hershey, PA, United States.,Department of Anesthesiology and Perioperative Medicine, Penn State University College of Medicine, Hershey, PA, United States
| | - LaTaijah C Crawford
- Department of Biomedical Sciences, Marshall University, Huntington, WV, United States.,Department of Anesthesiology and Perioperative Medicine, Penn State University College of Medicine, Hershey, PA, United States
| | - Diana E Sepulveda
- Department of Pharmacology, Penn State University College of Medicine, Hershey, PA, United States.,Department of Anesthesiology and Perioperative Medicine, Penn State University College of Medicine, Hershey, PA, United States
| | - David E Hale
- Department of Anesthesiology and Perioperative Medicine, Penn State University College of Medicine, Hershey, PA, United States
| | - Julia J Lesperance
- Department of Anesthesiology and Perioperative Medicine, Penn State University College of Medicine, Hershey, PA, United States
| | - Daniel J Morgan
- Department of Biomedical Sciences, Marshall University, Huntington, WV, United States.,Department of Pharmacology, Penn State University College of Medicine, Hershey, PA, United States.,Department of Anesthesiology and Perioperative Medicine, Penn State University College of Medicine, Hershey, PA, United States.,Department of Neural and Behavioral Sciences, Penn State University College of Medicine, Hershey, PA, United States
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58
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Lu J, Yang L, Xu Y, Ai L, Chen J, Xiong F, Hu L, Chen H, Liu J, Yan X, Huang H, Chen L, Yu C. The Modulatory Effect of Motor Cortex Astrocytes on Diabetic Neuropathic Pain. J Neurosci 2021; 41:5287-5302. [PMID: 33753547 PMCID: PMC8211549 DOI: 10.1523/jneurosci.2566-20.2021] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Revised: 02/11/2021] [Accepted: 03/11/2021] [Indexed: 02/01/2023] Open
Abstract
Diabetic neuropathic pain (DNP) is a common complication of diabetes characterized by persistent pain. Emerging evidence links astrocytes to mechanical nociceptive processing, and the motor cortex (MCx) is a cerebral cortex region that is known to play a key role in pain regulation. However, the association between MCx astrocytes and DNP pathogenesis remains largely unexplored. Here, we studied this association using designer receptors exclusively activated by designer drugs to specifically manipulate MCx astrocytes. We proved that the selective inhibition of MCx astrocytes reduced DNP in streptozocin (STZ)-induced DNP models and discovered a potential mechanism by which astrocytes release cytokines, including TNF-α and IL-1β, to increase neuronal activation in the MCx, thereby regulating pain. Together, these results demonstrate a pivotal role for MCx astrocytes in DNP pathogenesis and provide new insight into DNP treatment strategies.
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Affiliation(s)
- Jingshan Lu
- Department of Pharmacology, School of Pharmacy, Fujian Medical University, Fuzhou, Fujian 350122, China
| | - Lan Yang
- Department of Pharmacology, School of Pharmacy, Fujian Medical University, Fuzhou, Fujian 350122, China
| | - Ying Xu
- Department of Pharmacology, School of Pharmacy, Fujian Medical University, Fuzhou, Fujian 350122, China
| | - Lijing Ai
- Department of Pharmacology, School of Pharmacy, Fujian Medical University, Fuzhou, Fujian 350122, China
| | - Jian Chen
- Department of Pharmacology, School of Pharmacy, Fujian Medical University, Fuzhou, Fujian 350122, China
| | - Fangfang Xiong
- Department of Pharmacology, School of Pharmacy, Fujian Medical University, Fuzhou, Fujian 350122, China
| | - Lihuan Hu
- Department of Pharmacology, School of Pharmacy, Fujian Medical University, Fuzhou, Fujian 350122, China
| | - Huoshu Chen
- Department of Pharmacology, School of Pharmacy, Fujian Medical University, Fuzhou, Fujian 350122, China
| | - Jiyuan Liu
- School of Clinical Medicine, Fujian Medical University, Fuzhou, Fujian 350122, China
| | - Xiongbin Yan
- School of Clinical Medicine, Fujian Medical University, Fuzhou, Fujian 350122, China
| | - Huihui Huang
- Department of Pharmacology, School of Pharmacy, Fujian Medical University, Fuzhou, Fujian 350122, China
| | - Li Chen
- Department of Pharmacology, School of Pharmacy, Fujian Medical University, Fuzhou, Fujian 350122, China
- Fujian Key Laboratory of Drug Target Discovery and Structural and Functional Research, Fujian Medical University, Fuzhou, Fujian 350122, China
| | - Changxi Yu
- Department of Pharmacology, School of Pharmacy, Fujian Medical University, Fuzhou, Fujian 350122, China
- Fujian Key Laboratory of Drug Target Discovery and Structural and Functional Research, Fujian Medical University, Fuzhou, Fujian 350122, China
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Mo SY, Bai SS, Xu XX, Liu Y, Fu KY, Sessle BJ, Cao Y, Xie QF. Astrocytes in the rostral ventromedial medulla contribute to the maintenance of oro-facial hyperalgesia induced by late removal of dental occlusal interference. J Oral Rehabil 2021; 49:207-218. [PMID: 34042200 DOI: 10.1111/joor.13211] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 04/29/2021] [Accepted: 05/18/2021] [Indexed: 11/27/2022]
Abstract
BACKGROUND Astrocytes in the rostral ventromedial medulla (RVM) contribute to descending pain modulation, but their role in oro-facial pain induced by persistent experimental dental occlusal interference (PEOI) or following EOI removal (REOI) is unknown. OBJECTIVE To explore the involvement of RVM astrocytes in PEOI-induced oro-facial hyperalgesia or its maintenance following REOI. METHODS Male rats were randomly assigned into five groups: sham-EOI, postoperative day 6 and 14 of PEOI (PEOI 6 d and PEOI 14 d), postoperative day 6 following REOI on day 3 (REOI 3 d) and postoperative day 14 following REOI on day 8 (REOI 8 d). The nociceptive head withdrawal threshold (HWT) and activities of RVM ON- or OFF-cells were recorded before and after intra-RVM astrocyte gap junction blocker carbenoxolone (CBX) microinjection. RVM astrocytes were labelled immunohistochemically with glial fibrillary acidic protein (GFAP) and analysed semi-quantitatively. RESULTS Persistent experimental dental occlusal interference-induced oro-facial hyperalgesia, as reflected in decreased HWTs, was partially inhibited by REOI at day 3 but not at day 8 after EOI placement. Increased GFAP-staining area occurred only in REOI 8 d group in which CBX could inhibit the maintained hyperalgesia; CBX was ineffective in inhibiting hyperalgesia in PEOI 14 d group. OFF-cell activities showed no change, but the spontaneous activity and responses of ON-cells were significantly enhanced that could be suppressed by CBX in REOI 8 d group. CONCLUSION Rostral ventromedial medulla astrocytes may not participate in PEOI-induced oro-facial hyperalgesia or hyperalgesia inhibition by early REOI but are involved in the maintenance of oro-facial hyperalgesia by late REOI.
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Affiliation(s)
- Si-Yi Mo
- Center for Oral and Jaw Functional Diagnosis, Treatment and Research, Department of Prosthodontics, Peking University School and Hospital of Stomatology & National Engineering Laboratory for Digital and Material Technology of Stomatology & Beijing Key Laboratory of Digital Stomatology, Beijing, China
| | - Shan-Shan Bai
- Center for Oral and Jaw Functional Diagnosis, Treatment and Research, Department of Prosthodontics, Peking University School and Hospital of Stomatology & National Engineering Laboratory for Digital and Material Technology of Stomatology & Beijing Key Laboratory of Digital Stomatology, Beijing, China
| | - Xiao-Xiang Xu
- Center for Oral and Jaw Functional Diagnosis, Treatment and Research, Department of Prosthodontics, Peking University School and Hospital of Stomatology & National Engineering Laboratory for Digital and Material Technology of Stomatology & Beijing Key Laboratory of Digital Stomatology, Beijing, China
| | - Yun Liu
- Center for Oral and Jaw Functional Diagnosis, Treatment and Research, Department of Prosthodontics, Peking University School and Hospital of Stomatology & National Engineering Laboratory for Digital and Material Technology of Stomatology & Beijing Key Laboratory of Digital Stomatology, Beijing, China
| | - Kai-Yuan Fu
- Center for TMD & Orofacial Pain, Peking University School & Hospital of Stomatology, Beijing, China
| | - Barry J Sessle
- Faculty of Dentistry, and Department of Physiology, Faculty of Medicine, and Centre for the Study of Pain, University of Toronto, Toronto, ON, Canada
| | - Ye Cao
- Center for Oral and Jaw Functional Diagnosis, Treatment and Research, Department of Prosthodontics, Peking University School and Hospital of Stomatology & National Engineering Laboratory for Digital and Material Technology of Stomatology & Beijing Key Laboratory of Digital Stomatology, Beijing, China
| | - Qiu-Fei Xie
- Center for Oral and Jaw Functional Diagnosis, Treatment and Research, Department of Prosthodontics, Peking University School and Hospital of Stomatology & National Engineering Laboratory for Digital and Material Technology of Stomatology & Beijing Key Laboratory of Digital Stomatology, Beijing, China
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Glia and Orofacial Pain: Progress and Future Directions. Int J Mol Sci 2021; 22:ijms22105345. [PMID: 34069553 PMCID: PMC8160907 DOI: 10.3390/ijms22105345] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 05/12/2021] [Accepted: 05/14/2021] [Indexed: 12/14/2022] Open
Abstract
Orofacial pain is a universal predicament, afflicting millions of individuals worldwide. Research on the molecular mechanisms of orofacial pain has predominately focused on the role of neurons underlying nociception. However, aside from neural mechanisms, non-neuronal cells, such as Schwann cells and satellite ganglion cells in the peripheral nervous system, and microglia and astrocytes in the central nervous system, are important players in both peripheral and central processing of pain in the orofacial region. This review highlights recent molecular and cellular findings of the glia involvement and glia–neuron interactions in four common orofacial pain conditions such as headache, dental pulp injury, temporomandibular joint dysfunction/inflammation, and head and neck cancer. We will discuss the remaining questions and future directions on glial involvement in these four orofacial pain conditions.
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Bhuiyan P, Chen Y, Karim M, Dong H, Qian Y. Bidirectional communication between mast cells and the gut-brain axis in neurodegenerative diseases: Avenues for therapeutic intervention. Brain Res Bull 2021; 172:61-78. [PMID: 33892083 DOI: 10.1016/j.brainresbull.2021.04.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 03/02/2021] [Accepted: 04/17/2021] [Indexed: 12/12/2022]
Abstract
Although the global incidence of neurodegenerative diseases has been steadily increasing, especially in adults, there are no effective therapeutic interventions. Neurodegeneration is a heterogeneous group of disorders that is characterized by the activation of immune cells in the central nervous system (CNS) (e.g., mast cells and microglia) and subsequent neuroinflammation. Mast cells are found in the brain and the gastrointestinal tract and play a role in "tuning" neuroimmune responses. The complex bidirectional communication between mast cells and gut microbiota coordinates various dynamic neuro-cellular responses, which propagates neuronal impulses from the gastrointestinal tract into the CNS. Numerous inflammatory mediators from degranulated mast cells alter intestinal gut permeability and disrupt blood-brain barrier, which results in the promotion of neuroinflammatory processes leading to neurological disorders, thereby offsetting the balance in immune-surveillance. Emerging evidence supports the hypothesis that gut-microbiota exert a pivotal role in inflammatory signaling through the activation of immune and inflammatory cells. Communication between inflammatory cytokines and neurocircuits via the gut-brain axis (GBA) affects behavioral responses, activates mast cells and microglia that causes neuroinflammation, which is associated with neurological diseases. In this comprehensive review, we focus on what is currently known about mast cells and the gut-brain axis relationship, and how this relationship is connected to neurodegenerative diseases. We hope that further elucidating the bidirectional communication between mast cells and the GBA will not only stimulate future research on neurodegenerative diseases but will also identify new opportunities for therapeutic interventions.
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Affiliation(s)
- Piplu Bhuiyan
- Department of Anesthesiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, 210029, PR China
| | - Yinan Chen
- Department of Anesthesiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, 210029, PR China
| | - Mazharul Karim
- College of Pharmacy, Western University of Health Science, 309 East 2nd Street, Pomona, CA, 91766, USA
| | - Hongquan Dong
- Department of Anesthesiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, 210029, PR China.
| | - Yanning Qian
- Department of Anesthesiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, 210029, PR China.
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Rapid elevation of brain-derived neurotrophic factor production in the bilateral trigeminal ganglia by unilateral transection of the mental nerve in mice. Neuroreport 2021; 32:659-665. [PMID: 33814543 DOI: 10.1097/wnr.0000000000001635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES Previous spinal nerve injury studies have reported brain-derived neurotrophic factor (BDNF) mRNA upregulation in either the ipsilateral dorsal root ganglion (DRG) neurons or both the contralateral and ipsilateral DRG neurons from early period after peripheral nerve injury. This BDNF elevation induces hyperalgesia in the injured and/or uninjured sites, but this detailed mechanism remains unknown. This study aimed to investigate the BDNF mRNA expression in bilateral DRG neurons caused by unilateral nerve injury and to explore the possible mechanisms by which nitric oxide (NO) mediates BDNF production in the DRG, resulting in contralateral hyperalgesia. METHODS Early changes in BDNF mRNA expression in the bilateral trigeminal ganglia, within 1 day after mental nerve transection, were examined. Additionally, the effects on BDNF production of the NO synthase inhibitor N(ω)-nitro-l-arginine methyl ester (L-NAME) were investigated in the bilateral trigeminal ganglia. The relationship between injured neurons and BDNF production in the trigeminal ganglia was then assessed using immunohistochemical and retrograde tracing methods. RESULTS Reverse transcription-PCR analysis demonstrated that unilateral transection of the mental nerve induced a rapid elevation of BDNF mRNA expression, which was inhibited by the intracerebroventricular administration of L-NAME prior to nerve transection. This effect was observed in both the ipsilateral and contralateral sides to the nerve transection. BDNF immunostaining combined with FluoroGold retrograde tracing revealed two types of BDNF-reactive neurons, FluoroGold-labelled and non-FluoroGold-labelled neurons, in the ipsilateral and contralateral sides of the trigeminal ganglia. BDNF-positive cells were also observed in the trigeminal ganglia of other trigeminal nerve branches. CONCLUSIONS Unilateral nerve injury upregulates BDNF production in the bilateral trigeminal ganglia by NO-mediated and/or indirect activation of afferent neurons, resulting in contralateral hyperalgesia.
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Iyer P, Lee YC. Why It Hurts: The Mechanisms of Pain in Rheumatoid Arthritis. Rheum Dis Clin North Am 2021; 47:229-244. [PMID: 33781492 DOI: 10.1016/j.rdc.2020.12.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Pain is a near-universal feature of rheumatoid arthritis, but peripheral joint inflammation may not suffice to explain the etiology of pain in all patients with rheumatoid arthritis. Inflammation in rheumatoid arthritis releases several algogens that may generate pain. Also, central nervous system processes may play a crucial role in the regulation and perpetuation of pain. Several methods for assessing pain in rheumatoid arthritis exist, and recently the role of assessing therapeutics in treating specific etiologies of pain has gained interest.
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Affiliation(s)
- Priyanka Iyer
- Division of Rheumatology, Department of Internal Medicine, University of California Irvine, Irvine, CA, USA.
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Meylakh N, Marciszewski KK, Di Pietro F, Macefield VG, Macey PM, Henderson LA. Brainstem functional oscillations across the migraine cycle: A longitudinal investigation. NEUROIMAGE-CLINICAL 2021; 30:102630. [PMID: 33770547 PMCID: PMC8024773 DOI: 10.1016/j.nicl.2021.102630] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 03/07/2021] [Accepted: 03/09/2021] [Indexed: 12/30/2022]
Abstract
Individual migraineurs’ brainstem function alters through the migraine cycle. Functional changes occurred in the 24-hour period immediately prior to a migraine. Greater resting activity variability was found in the SpV, pons and PAG. Increased infra-slow oscillations and regional homogeneity in the SpV and pons.
Although the mechanisms responsible for migraine initiation remain unknown, recent evidence shows that brain function is different immediately preceding a migraine. This is consistent with the idea that altered brain function, particularly in brainstem sites, may either trigger a migraine or facilitate a peripheral trigger that activates the brain, resulting in pain. The aim of this longitudinal study is therefore to expand on the above findings, and to determine if brainstem function oscillates over a migraine cycle in individual subjects. We performed resting state functional magnetic resonance imaging in three migraineurs and five controls each weekday for four weeks. We found that although resting activity variability was similar in controls and interictal migraineurs, brainstem variability increased dramatically during the 24-hour period preceding a migraine. This increase occurred in brainstem areas in which orofacial afferents terminate: the spinal trigeminal nucleus and dorsal pons. These increases were characterized by increased power at infra-slow frequencies, principally between 0.03 and 0.06 Hz. Furthermore, these power increases were associated with increased regional homogeneity, a measure of local signal coherence. The results show within-individual alterations in brain activity immediately preceding migraine onset and support the hypothesis that altered regional brainstem function before a migraine attack is involved in underlying migraine neurobiology.
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Affiliation(s)
- Noemi Meylakh
- Department of Anatomy and Histology, University of Sydney, Sydney, NSW 2006, Australia.
| | - Kasia K Marciszewski
- Department of Anatomy and Histology, University of Sydney, Sydney, NSW 2006, Australia
| | - Flavia Di Pietro
- School of Pharmacy and Biomedical Sciences, Curtin University, Perth, Australia
| | | | - Paul M Macey
- UCLA School of Nursing and Brain Research Institute, University of California, Los Angeles, CA 90095, United States
| | - Luke A Henderson
- Department of Anatomy and Histology, University of Sydney, Sydney, NSW 2006, Australia
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Li Y, Yang Y, Guo J, Guo X, Feng Z, Zhao X. Spinal NF-kB upregulation contributes to hyperalgesia in a rat model of advanced osteoarthritis. Mol Pain 2021; 16:1744806920905691. [PMID: 31971058 PMCID: PMC7040927 DOI: 10.1177/1744806920905691] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Knee osteoarthritis (OA) pain is the most common joint pain. Currently, dysfunction in the central nervous system rather than knee joint degeneration is considered to be the major cause of chronic knee OA pain; however, the underlying mechanism remains unknown. The aim of this study was to explore whether spinal NF-κB plays a critical role in chronic knee OA pain. In this study, we used a model induced by the intra-articular injection of monosodium iodoacetate. Spinal NF-κB and the phosphorylation and activation status of NF-κB p65/RelA (p-p65) were inhibited by the intrathecal injection of the inhibitor pyrrolidine dithiocarbamate in this model. After behavioral assessment, the knee was dissected for histopathology, and the spinal cord was dissected and examined for NF-κB, p-p65, and cytokine expression. Furthermore, the quantity and activity of neurons, astrocytes, and microglial cells and their colocalization with p-p65 in the spinal dorsal horn were investigated. Our findings included the following: (1) histology, the pathological changes in the joints of the knee OA model were basically consistent with knee OA patients; (2) the protein and transcription levels of NF-κB/p65 and p-p65 increased before day 14, appeared to decrease on day 21 and increased again on day 28, and the tendency of weight bearing was similar; (3) on days 21 and 28, the intrathecal injection of pyrrolidine dithiocarbamate markedly prevented the monosodium iodoacetate-induced reduction in the paw withdrawal threshold; (4) real-time polymerase chain reaction demonstrated that the expression of TNF-α and IL-33 was suppressed in the knee OA model by the intrathecal injection of pyrrolidine dithiocarbamate; and (5) immunofluorescence revealed that astrocytes were activated and that p-p65 was mainly increased in astrocytes. Our findings indicate that the spinal NF-κB/p65 pathway in astrocytes modulates neuroimmunity in rat model of intra-articular monosodium iodoacetate-induced advanced OA.
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Affiliation(s)
- Yunze Li
- Department of Pain Medicine, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China.,Department of Pain Medicine, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yixin Yang
- Department of Pain Medicine, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Jinwan Guo
- Department of Anesthesiology, Shandong Provincial Qianfoshan Hospital, Jinan, China
| | - Xuejiao Guo
- Department of Pain Medicine, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhiying Feng
- Department of Pain Medicine, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xuli Zhao
- Department of Pain Medicine, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China
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WeiWei Y, WenDi F, Mengru C, Tuo Y, Chen G. The cellular mechanism by which the rostral ventromedial medulla acts on the spinal cord during chronic pain. Rev Neurosci 2021; 32:545-558. [PMID: 33565739 DOI: 10.1515/revneuro-2020-0121] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Accepted: 12/18/2020] [Indexed: 11/15/2022]
Abstract
Clinical therapies for chronic pain are limited. While targeted drugs are promising therapies for chronic pain, they exhibit insufficient efficacy and poor targeting. The occurrence of chronic pain partly results from central changes caused by alterations in neurons in the rostral ventromedial medulla (RVM) in the brainstem regulatory pathway. The RVM, which plays a key role in the descending pain control pathway, greatly contributes to the development and maintenance of pain. However, the exact roles of the RVM in chronic pain remain unclear, making it difficult to develop new drugs targeting the RVM and related pathways. Here, we first discuss the roles of the RVM and related circuits in chronic pain. Then, we analyze synaptic transmission between RVM neurons and spinal cord neurons, specifically focusing on the release of neurotransmitters, to explore the cellular mechanisms by which the RVM regulates chronic pain. Finally, we propose some ideas for the development of drugs targeting the RVM.
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Affiliation(s)
- Yu WeiWei
- Key Laboratory of Neuroregeneration of Jiangsu and the Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong226001, China
| | - Fei WenDi
- Key Laboratory of Neuroregeneration of Jiangsu and the Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong226001, China
| | - Cui Mengru
- Department of Anesthesiology, Affiliated Hospital of Nantong University, Nantong226001, China
| | - Yang Tuo
- Department of Hand Surgery, China-Japan Union Hospital of Jilin University, Changchun130033, China
| | - Gang Chen
- Department of Anesthesiology, Affiliated Hospital of Nantong University, Nantong226001, China.,Department of Tissue and Embryology, Medical School of Nantong University, Co-innovation Center of Neuroregeneration, Nantong University, Nantong226001, China
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Charvériat M, Mouthon F, Rein W, Verkhratsky A. Connexins as therapeutic targets in neurological and neuropsychiatric disorders. Biochim Biophys Acta Mol Basis Dis 2021; 1867:166098. [PMID: 33545299 DOI: 10.1016/j.bbadis.2021.166098] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 01/06/2021] [Accepted: 01/19/2021] [Indexed: 12/16/2022]
Abstract
Astrocytes represent the reticular part of the central nervous system; gap junctions formed by connexins Cx43, Cx30- and Cx26 provide for homocellular astrocyte-astrocyte coupling, whereas connexins Cx30, Cx32, Cx43, and Cx47 connect astrocytes and oligodendrocytes. Astroglial networks are anatomically and functionally segregated being homologous to neuronal ensembles. Connexons, gap junctions and hemichannels (unpaired connexons) are affected in various neuropathologies from neuropsychiatric to neurodegenerative diseases. Manipulation of astrocytic connexins modulates the size and outreach of astroglial syncytia thus affecting astroglial homeostatic support. Modulation of astrocytic connexin significantly modifies pharmacological profile of many CNS drugs, which represents an innovative therapeutic approach for CNS disorders; this approach is now actively tested in pre-clinical and clinical studies. Wide combination of connexin modulators with CNS drugs open new promising perspectives for fundamental studies and therapeutic strategies.
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Affiliation(s)
| | | | | | - A Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, UK; Achucarro Centre for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain
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Use of low-dose naltrexone in the management of chronic pain conditions: A systematic review. J Am Dent Assoc 2021; 151:891-902.e1. [PMID: 33228882 DOI: 10.1016/j.adaj.2020.08.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Accepted: 08/19/2020] [Indexed: 12/23/2022]
Abstract
BACKGROUND The authors aimed to evaluate the efficacy of low-dose naltrexone in the management of chronic pain conditions and determine its potential use in orofacial pain management. METHODS A comprehensive literature review was completed in the PubMed/MEDLINE, Embase, Cumulated Index to Nursing and Allied Health Literature, Dentistry and Oral Sciences Source Library databases up through June 17, 2019, using terms such as neurogenic, inflammation, naltrexone, temporomandibular, and chronic pain. The primary outcome was reduction in pain intensity and, secondarily, improvement in quality of life. RESULTS A total of 793 studies were obtained with the initial search and 8 articles were selected for evaluation. Of these 8 articles, 4 were case reports, 3 were clinical studies, and 1 was a randomized controlled trial. Six studies included data on fibromyalgia, 2 studies included data on chronic regional pain syndrome, and 1 examined multiple diagnoses, including fibromyalgia, interstitial cystitis, and chronic pelvic pain. The primary outcome of all of the studies was pain intensity reduction. CONCLUSIONS AND PRACTICAL IMPLICATIONS Low-dose naltrexone provides an alternative in medical management of chronic pain disorders as a novel anti-inflammatory and immunomodulator. It can offer additional management options, as orofacial pain conditions share characteristics with other chronic pain disorders. Owing to the size and heterogeneity of the studies, more large-scale studies are needed, along with additional studies assessing orofacial pain response to low-dose naltrexone.
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Leiguarda C, Villarreal A, Potilinski C, Pelissier T, Coronel MF, Bayo J, Ramos AJ, Montaner A, Villar MJ, Constandil L, Brumovsky PR. Intrathecal Administration of an Anti-nociceptive Non-CpG Oligodeoxynucleotide Reduces Glial Activation and Central Sensitization. J Neuroimmune Pharmacol 2021; 16:818-834. [PMID: 33502706 DOI: 10.1007/s11481-021-09983-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 01/12/2021] [Indexed: 01/18/2023]
Abstract
Inflammatory pain associates with spinal glial activation and central sensitization. Systemic administration of IMT504, a non-CpG oligodeoxynucleotide originally designed as an immunomodulator, exerts remarkable anti-allodynic effects in rats with complete Freund´s adjuvant (CFA)-induced hindpaw inflammation. However, the anti-nociceptive mechanisms of IMT504 remain unknown. Here we evaluated whether IMT504 blocks inflammatory pain-like behavior by modulation of spinal glia and central sensitization. The study was performed in Sprague Dawley rats with intraplantar CFA, and a single lumbosacral intrathecal (i.t.) administration of IMT504 or vehicle was chosen to address if changes in glial activation and spinal sensitization relate to the pain-like behavior reducing effects of the ODN. Naïve rats were also included. Von Frey and Randall-Selitto tests, respectively, exposed significant reductions in allodynia and mechanical hypersensitivity, lasting at least 24 h after i.t. IMT504. Analysis of electromyographic responses to electrical stimulation of C fibers showed progressive reductions in wind-up responses. Accordingly, IMT504 significantly downregulated spinal glial activation, as shown by reductions in the protein expression of glial fibrillary acidic protein, CD11b/c, Toll-like receptor 4 (TLR4) and the phosphorylated p65 subunit of NFκB, evaluated by immunohistochemistry and western blot. In vitro experiments using early post-natal cortical glial cultures provided further support to in vivo data and demonstrated IMT504 internalization into microglia and astrocytes. Altogether, our study provides new evidence on the central mechanisms of anti-nociception by IMT504 upon intrathecal application, and further supports its value as a novel anti-inflammatory ODN with actions upon glial cells and the TLR4/NFκB pathway. Intrathecal administration of the non-CpG ODN IMT504 fully blocks CFA-induced mechanical allodynia and hypersensitivity, in association with reduced spinal sensitization. Administration of the ODN also results in downregulated gliosis and reduced TLR4-NF-κB pathway activation. IMT504 uptake into astrocytes and microglia support the concept of direct modulation of CFA-induced glial activation.
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Affiliation(s)
- C Leiguarda
- Instituto de Investigaciones en Medicina Traslacional (IIMT), Universidad Austral-CONICET, Av. Juan D. Perón 1500, Pilar, Buenos Aires, B1629AHJ, Argentina
| | - A Villarreal
- Laboratorio de Neuropatología Molecular, Instituto de Biología Celular y Neurociencia "Prof. E. De Robertis" UBA-CONICET, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, 1121, Argentina
| | - C Potilinski
- Instituto de Investigaciones en Medicina Traslacional (IIMT), Universidad Austral-CONICET, Av. Juan D. Perón 1500, Pilar, Buenos Aires, B1629AHJ, Argentina
| | - T Pelissier
- Laboratorio de Neurobiología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, 8320000, Chile
| | - M F Coronel
- Instituto de Investigaciones en Medicina Traslacional (IIMT), Universidad Austral-CONICET, Av. Juan D. Perón 1500, Pilar, Buenos Aires, B1629AHJ, Argentina
| | - J Bayo
- Instituto de Investigaciones en Medicina Traslacional (IIMT), Universidad Austral-CONICET, Av. Juan D. Perón 1500, Pilar, Buenos Aires, B1629AHJ, Argentina
| | - A J Ramos
- Laboratorio de Neuropatología Molecular, Instituto de Biología Celular y Neurociencia "Prof. E. De Robertis" UBA-CONICET, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, 1121, Argentina
- Departamento de Histología, Embriología, Biología Celular y Genética, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, 1121, Argentina
| | - A Montaner
- Instituto de Ciencia y Tecnología "Dr. César Milstein", CONICET, Fundación Pablo Cassará, Buenos Aires, C1440FFX, Argentina
| | - M J Villar
- Instituto de Investigaciones en Medicina Traslacional (IIMT), Universidad Austral-CONICET, Av. Juan D. Perón 1500, Pilar, Buenos Aires, B1629AHJ, Argentina
| | - L Constandil
- Laboratorio de Neurobiología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, 8320000, Chile
| | - Pablo R Brumovsky
- Instituto de Investigaciones en Medicina Traslacional (IIMT), Universidad Austral-CONICET, Av. Juan D. Perón 1500, Pilar, Buenos Aires, B1629AHJ, Argentina.
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Kitayama T. The Role of Astrocytes in the Modulation ofK +-Cl --Cotransporter-2 Function. Int J Mol Sci 2020; 21:E9539. [PMID: 33333849 PMCID: PMC7765297 DOI: 10.3390/ijms21249539] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 12/10/2020] [Accepted: 12/13/2020] [Indexed: 11/21/2022] Open
Abstract
Neuropathic pain is characterized by spontaneous pain, pain sensations, and tactile allodynia. The pain sensory system normally functions under a fine balance between excitation and inhibition. Neuropathic pain arises when this balance is lost for some reason. In past reports, various mechanisms of neuropathic pain development have been reported, one of which is the downregulation of K+-Cl--cotransporter-2 (KCC2) expression. In fact, various neuropathic pain models indicate a decrease in KCC2 expression. This decrease in KCC2 expression is often due to a brain-derived neurotrophic factor that is released from microglia. However, a similar reaction has been reported in astrocytes, and it is unclear whether astrocytes or microglia are more important. This review discusses the hypothesis that astrocytes have a crucial influence on the alteration of KCC2 expression.
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Affiliation(s)
- Tomoya Kitayama
- School of Pharmacy and Pharmaceutical Sciences, Mukogawa Women's University, Hyogo 663-8179, Japan
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71
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Borsom EM, Lee K, Cope EK. Do the Bugs in Your Gut Eat Your Memories? Relationship between Gut Microbiota and Alzheimer's Disease. Brain Sci 2020; 10:E814. [PMID: 33153085 PMCID: PMC7693835 DOI: 10.3390/brainsci10110814] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 10/29/2020] [Accepted: 10/31/2020] [Indexed: 02/06/2023] Open
Abstract
The human microbiota is composed of trillions of microbial cells inhabiting the oral cavity, skin, gastrointestinal (GI) tract, airways, and reproductive organs. The gut microbiota is composed of dynamic communities of microorganisms that communicate bidirectionally with the brain via cytokines, neurotransmitters, hormones, and secondary metabolites, known as the gut microbiota-brain axis. The gut microbiota-brain axis is suspected to be involved in the development of neurological diseases, including Alzheimer's disease (AD), Parkinson's disease, and Autism Spectrum Disorder. AD is an irreversible, neurodegenerative disease of the central nervous system (CNS), characterized by amyloid-β plaques, neurofibrillary tangles, and neuroinflammation. Microglia and astrocytes, the resident immune cells of the CNS, play an integral role in AD development, as neuroinflammation is a driving factor of disease severity. The gut microbiota-brain axis is a novel target for Alzheimer's disease therapeutics to modulate critical neuroimmune and metabolic pathways. Potential therapeutics include probiotics, prebiotics, fecal microbiota transplantation, and dietary intervention. This review summarizes our current understanding of the role of the gut microbiota-brain axis and neuroinflammation in the onset and development of Alzheimer's disease, limitations of current research, and potential for gut microbiota-brain axis targeted therapies.
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Kwok CHT, Learoyd AE, Canet-Pons J, Trang T, Fitzgerald M. Spinal interleukin-6 contributes to central sensitisation and persistent pain hypersensitivity in a model of juvenile idiopathic arthritis. Brain Behav Immun 2020; 90:145-154. [PMID: 32791212 PMCID: PMC7575902 DOI: 10.1016/j.bbi.2020.08.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 07/27/2020] [Accepted: 08/07/2020] [Indexed: 12/15/2022] Open
Abstract
Pain is the most debilitating symptom in juvenile idiopathic arthritis. As pain correlates poorly to the extent of joint pathology, therapies that control joint inflammation are often inadequate as analgesics. We test the hypothesis that juvenile joint inflammation leads to sensitisation of nociceptive circuits in the central nervous system, which is maintained by cytokine expression in the spinal cord. Here, transient joint inflammation was induced in postnatal day (P)21 and P40 male Sprague-Dawley rats with a single intra-articular ankle injection of complete Freund's adjuvant. Hindpaw mechanical pain sensitivity was assessed using von Frey hair and weight bearing tests. Spinal neuron activity was measured using in vivo extracellular recording and immunohistochemistry. Joint and spinal dorsal horn TNFα, IL1β and IL6 protein expression was quantified using western blotting. We observed greater mechanical hyperalgesia following joint inflammation in P21 compared to P40 rats, despite comparable duration of swelling and joint inflammatory cytokine levels. This is mirrored by spinal neuron hypersensitivity, which also outlasted the duration of active joint inflammation. The cytokine profile in the spinal cord differed at the two ages: prolonged upregulation of spinal IL6 was observed in P21, but not P40 rats. Finally, spinal application of anti-IL-6 antibody (30 ng) reduced the mechanical hyperalgesia and neuronal activation. Our results indicate that persistent upregulation of pro-inflammatory cytokines in the spinal dorsal horn is associated with neuronal sensitisation and mechanical hyperalgesia in juvenile rats, beyond the progress of joint pathology. In addition, we provide proof of concept that spinal IL6 is a key target for treating persistent pain in JIA.
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Affiliation(s)
- Charlie H T Kwok
- Physiology and Pharmacology, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada; Comparative Biology and Experimental Medicine, University of Calgary, Calgary, Alberta, Canada.
| | - Annastazia E Learoyd
- Department of Neuroscience, Physiology and Pharmacology, University College London, UK
| | - Julia Canet-Pons
- Physiology and Pharmacology, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada; Comparative Biology and Experimental Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Tuan Trang
- Physiology and Pharmacology, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada; Comparative Biology and Experimental Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Maria Fitzgerald
- Department of Neuroscience, Physiology and Pharmacology, University College London, UK
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Leisengang S, Nürnberger F, Ott D, Murgott J, Gerstberger R, Rummel C, Roth J. Primary culture of the rat spinal dorsal horn: a tool to investigate the effects of inflammatory stimulation on the afferent somatosensory system. Pflugers Arch 2020; 472:1769-1782. [PMID: 33098464 PMCID: PMC7691309 DOI: 10.1007/s00424-020-02478-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 08/28/2020] [Accepted: 10/14/2020] [Indexed: 02/06/2023]
Abstract
One maladaptive consequence of inflammatory stimulation of the afferent somatosensory system is the manifestation of inflammatory pain. We established and characterized a neuroglial primary culture of the rat superficial dorsal horn (SDH) of the spinal cord to test responses of this structure to neurochemical, somatosensory, or inflammatory stimulation. Primary cultures of the rat SDH consist of neurons (43%), oligodendrocytes (35%), astrocytes (13%), and microglial cells (9%). Neurons of the SDH responded to cooling (7%), heating (18%), glutamate (80%), substance P (43%), prostaglandin E2 (8%), and KCl (100%) with transient increases in the intracellular calcium [Ca2+]i. Short-term stimulation of SDH primary cultures with LPS (10 μg/ml, 2 h) caused increased expression of pro-inflammatory cytokines, inflammatory transcription factors, and inducible enzymes responsible for inflammatory prostaglandin E2 synthesis. At the protein level, increased concentrations of tumor necrosis factor-α (TNFα) and interleukin-6 (IL-6) were measured in the supernatants of LPS-stimulated SDH cultures and enhanced TNFα and IL-6 immunoreactivity was observed specifically in microglial cells. LPS-exposed microglial cells further showed increased nuclear immunoreactivity for the inflammatory transcription factors NFκB, NF-IL6, and pCREB, indicative of their activation. The short-term exposure to LPS further caused a reduction in the strength of substance P as opposed to glutamate-evoked Ca2+-signals in SDH neurons. However, long-term stimulation with a low dose of LPS (0.01 μg/ml, 24 h) resulted in a significant enhancement of glutamate-induced Ca2+ transients in SDH neurons, while substance P-evoked Ca2+ signals were not influenced. Our data suggest a critical role for microglial cells in the initiation of inflammatory processes within the SDH of the spinal cord, which are accompanied by a modulation of neuronal responses.
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Affiliation(s)
- Stephan Leisengang
- Department of Veterinary Physiology and Biochemistry, Justus-Liebig-University Giessen, Frankfurter Strasse 100, 35392, Giessen, Germany.,Center for Mind, Brain and Behavior - CMBB, Philipps-University Marburg, Marburg, Germany.,Center for Mind, Brain and Behavior - CMBB, Justus-Liebig-University of Giessen, Giessen, Germany
| | - Franz Nürnberger
- Department of Veterinary Physiology and Biochemistry, Justus-Liebig-University Giessen, Frankfurter Strasse 100, 35392, Giessen, Germany
| | - Daniela Ott
- Department of Veterinary Physiology and Biochemistry, Justus-Liebig-University Giessen, Frankfurter Strasse 100, 35392, Giessen, Germany
| | - Jolanta Murgott
- Department of Veterinary Physiology and Biochemistry, Justus-Liebig-University Giessen, Frankfurter Strasse 100, 35392, Giessen, Germany
| | - Rüdiger Gerstberger
- Department of Veterinary Physiology and Biochemistry, Justus-Liebig-University Giessen, Frankfurter Strasse 100, 35392, Giessen, Germany
| | - Christoph Rummel
- Department of Veterinary Physiology and Biochemistry, Justus-Liebig-University Giessen, Frankfurter Strasse 100, 35392, Giessen, Germany.,Center for Mind, Brain and Behavior - CMBB, Philipps-University Marburg, Marburg, Germany.,Center for Mind, Brain and Behavior - CMBB, Justus-Liebig-University of Giessen, Giessen, Germany
| | - Joachim Roth
- Department of Veterinary Physiology and Biochemistry, Justus-Liebig-University Giessen, Frankfurter Strasse 100, 35392, Giessen, Germany. .,Center for Mind, Brain and Behavior - CMBB, Philipps-University Marburg, Marburg, Germany. .,Center for Mind, Brain and Behavior - CMBB, Justus-Liebig-University of Giessen, Giessen, Germany.
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74
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Ren K. Grand Challenges in Musculoskeletal Pain Research: Chronicity, Comorbidity, Immune Regulation, Sex Differences, Diagnosis, and Treatment Opportunities. FRONTIERS IN PAIN RESEARCH 2020; 1. [PMID: 34296207 PMCID: PMC8294784 DOI: 10.3389/fpain.2020.575479] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Affiliation(s)
- Ke Ren
- Department of Neural and Pain Sciences, School of Dentistry, University of Maryland, Baltimore, MD, United States.,Program in Neuroscience, University of Maryland, Baltimore, MD, United States
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75
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Kim YS, Choi J, Yoon BE. Neuron-Glia Interactions in Neurodevelopmental Disorders. Cells 2020; 9:cells9102176. [PMID: 32992620 PMCID: PMC7601502 DOI: 10.3390/cells9102176] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 09/24/2020] [Accepted: 09/24/2020] [Indexed: 12/12/2022] Open
Abstract
Recent studies have revealed synaptic dysfunction to be a hallmark of various psychiatric diseases, and that glial cells participate in synapse formation, development, and plasticity. Glial cells contribute to neuroinflammation and synaptic homeostasis, the latter being essential for maintaining the physiological function of the central nervous system (CNS). In particular, glial cells undergo gliotransmission and regulate neuronal activity in tripartite synapses via ion channels (gap junction hemichannel, volume regulated anion channel, and bestrophin-1), receptors (for neurotransmitters and cytokines), or transporters (GLT-1, GLAST, and GATs) that are expressed on glial cell membranes. In this review, we propose that dysfunction in neuron-glia interactions may contribute to the pathogenesis of neurodevelopmental disorders. Understanding the mechanisms of neuron-glia interaction for synapse formation and maturation will contribute to the development of novel therapeutic targets of neurodevelopmental disorders.
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Affiliation(s)
- Yoo Sung Kim
- Department of Molecular Biology, Dankook University, Cheonan 31116, Korea; (Y.S.K.); (J.C.)
| | - Juwon Choi
- Department of Molecular Biology, Dankook University, Cheonan 31116, Korea; (Y.S.K.); (J.C.)
| | - Bo-Eun Yoon
- Department of Molecular Biology, Dankook University, Cheonan 31116, Korea; (Y.S.K.); (J.C.)
- Department of Nanobiomedical science, Dankook University, Cheonan 31116, Korea
- Correspondence: ; Tel.: +82-41-529-6085
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76
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Luo H, Liu HZ, Zhang WW, Matsuda M, Lv N, Chen G, Xu ZZ, Zhang YQ. Interleukin-17 Regulates Neuron-Glial Communications, Synaptic Transmission, and Neuropathic Pain after Chemotherapy. Cell Rep 2020; 29:2384-2397.e5. [PMID: 31747607 DOI: 10.1016/j.celrep.2019.10.085] [Citation(s) in RCA: 85] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 08/14/2019] [Accepted: 10/22/2019] [Indexed: 02/08/2023] Open
Abstract
The proinflammatory cytokine interleukin-17 (IL-17) is implicated in pain regulation. However, the synaptic mechanisms by which IL-17 regulates pain transmission are unknown. Here, we report that glia-produced IL-17 suppresses inhibitory synaptic transmission in the spinal cord pain circuit and drives chemotherapy-induced neuropathic pain. We find that IL-17 not only enhances excitatory postsynaptic currents (EPSCs) but also suppresses inhibitory postsynaptic synaptic currents (IPSCs) and GABA-induced currents in lamina IIo somatostatin-expressing neurons in mouse spinal cord slices. IL-17 mainly expresses in spinal cord astrocytes, and its receptor IL-17R is detected in somatostatin-expressing neurons. Selective knockdown of IL-17R in spinal somatostatin-expressing interneurons reduces paclitaxel-induced hypersensitivity. Overexpression of IL-17 in spinal astrocytes is sufficient to induce mechanical allodynia in naive animals. In dorsal root ganglia, IL-17R expression in nociceptive sensory neurons is sufficient and required for inducing neuronal hyperexcitability after paclitaxel. Together, our data show that IL-17/IL-17R mediate neuron-glial interactions and neuronal hyperexcitability in chemotherapy-induced peripheral neuropathy.
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Affiliation(s)
- Hao Luo
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Department of Translational Neuroscience, Jing'an District Centre Hospital of Shanghai, Institutes of Brain Science, Institutes of Integrative Medicine, Fudan University, Shanghai 200032, China
| | - Hui-Zhu Liu
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Department of Translational Neuroscience, Jing'an District Centre Hospital of Shanghai, Institutes of Brain Science, Institutes of Integrative Medicine, Fudan University, Shanghai 200032, China
| | - Wen-Wen Zhang
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Department of Translational Neuroscience, Jing'an District Centre Hospital of Shanghai, Institutes of Brain Science, Institutes of Integrative Medicine, Fudan University, Shanghai 200032, China
| | - Megumi Matsuda
- Research Unit for the Neurobiology of Pain, Department of Anesthesiology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Ning Lv
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Department of Translational Neuroscience, Jing'an District Centre Hospital of Shanghai, Institutes of Brain Science, Institutes of Integrative Medicine, Fudan University, Shanghai 200032, China
| | - Gang Chen
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China
| | - Zhen-Zhong Xu
- Department of Physiology, Center of Neuroscience, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University School of Medicine, Hangzhou, China
| | - Yu-Qiu Zhang
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Department of Translational Neuroscience, Jing'an District Centre Hospital of Shanghai, Institutes of Brain Science, Institutes of Integrative Medicine, Fudan University, Shanghai 200032, China.
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77
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Fundamental sex differences in morphine withdrawal-induced neuronal plasticity. Pain 2020; 161:2022-2034. [PMID: 32345917 DOI: 10.1097/j.pain.0000000000001901] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 04/21/2020] [Indexed: 12/25/2022]
Abstract
ABSTRACT Withdrawal from systemic opioids can induce long-term potentiation (LTP) at spinal C-fibre synapses ("opioid-withdrawal-LTP"). This is considered to be a cellular mechanism underlying opioid withdrawal-induced hyperalgesia, which is a major symptom of the opioid withdrawal syndrome. Opioids can activate glial cells leading to the release of proinflammatory mediators. These may influence synaptic plasticity and could thus contribute to opioid-withdrawal-LTP. Here, we report a sexual dimorphism in the mechanisms of morphine-withdrawal-LTP in adult rats. We recorded C-fibre-evoked field potentials in the spinal cord dorsal horn from deeply anaesthetised male and female rats. In both sexes, we induced a robust LTP through withdrawal from systemic morphine infusion (8 mg·kg-1 bolus, followed by a 1-hour infusion at a rate of 14 mg·kg-1·h-1). This paradigm also induced mechanical hypersensitivity of similar magnitude in both sexes. In male rats, systemic but not spinal application of (-)naloxone blocked the induction of morphine-withdrawal-LTP, suggesting the involvement of descending pronociceptive pathways. Furthermore, we showed that in male rats, the induction of morphine-withdrawal-LTP required the activation of spinal astrocytes and the release of the proinflammatory cytokines tumour necrosis factor and interleukin-1. In striking contrast, in female rats, the induction of morphine-withdrawal-LTP was independent of spinal glial cells. Instead, blocking µ-opioid receptors in the spinal cord was sufficient to prevent a facilitation of synaptic strength. Our study revealed fundamental sex differences in the mechanisms underlying morphine-withdrawal-LTP at C-fibre synapses: supraspinal and gliogenic mechanisms in males and a spinal, glial cell-independent mechanism in females.
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78
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Li CX, Liu J, Zhou KX, Zhao WJ, Zhao Y, Jin ZL, Gu ZX. Involvement of astrocytes activation in orofacial hyperalgesia induced by experimental tooth movement. Orthod Craniofac Res 2020; 24:147-154. [PMID: 32767851 DOI: 10.1111/ocr.12418] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Revised: 07/28/2020] [Accepted: 08/03/2020] [Indexed: 12/28/2022]
Abstract
OBJECTIVE The study aimed to investigate the involvement of astrocytes in the medullary dorsal horn (MDH) in the orofacial hyperalgesia induced by experimental tooth movement (ETM) and related mechanism. MATERIALS AND METHODS Experimental tooth movement was produced with nickel-titanium alloy closed-coil spring fixed between the left maxillary first molar and the left upper incisor. Fluorocitrate was administrated through medullary subarachnoid at 3 days after ETM. Pressure pain threshold (PPT) in masseter cutaneous area was measured. The expression of glial fibrillary acidic protein (GFAP) and c-Fos in MDH was measured using immunofluoroscence staining. The expression of interleukin-1β (IL-1β) and phosphorylated N-methyl-D-aspartic acid (NMDA) receptor subunit NR1 (p-NR1) was measured with Western blotting. RESULTS Experimental tooth movement-induced orofacial hyperalgesia from 1 to 9 days as the PPT was significantly reduced (P < .05). Immunofluoroscence staining showed that the expression of c-Fos in MDH was dramatically upregulated at 1 day and 3 days after ETM, while GFAP expression with both immunofluoroscence staining and Western blotting was significantly enhanced at 3 days and 7 days after ETM. Western blotting analysis indicated that the expression of IL-1β and p-NR1 in MDH was significantly enhanced at 3 days after ETM. Furthermore, we found that fluorocitrate administration at 3 days after ETM could markedly suppress the expression of c-Fos, GFAP, IL-1β and p-NR1 and attenuate the reduction of PPT induced by ETM. CONCLUSION Astrocyte activation in MDH is involved in the mechanical hyperalgesia, and the subsequent upregulated IL-1β and overexpression of p-NR1 may participate in this process.
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Affiliation(s)
- Cui-Xia Li
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Clinical Research Center for Oral Diseases, Department of Orthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, China
| | - Jia Liu
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Clinical Research Center for Oral Diseases, Department of Orthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, China
| | - Kai-Xiang Zhou
- Department of Anatomy, Histology and Embryology, K.K. Leung Brain Research Centre, Fourth Military Medical University, Xi'an, China
| | - Wen-Jun Zhao
- Department of Anatomy, Histology and Embryology, K.K. Leung Brain Research Centre, Fourth Military Medical University, Xi'an, China
| | - Yan Zhao
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Clinical Research Center for Oral Diseases, Department of Orthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, China
| | - Zuo-Lin Jin
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Clinical Research Center for Oral Diseases, Department of Orthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, China
| | - Ze-Xu Gu
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Clinical Research Center for Oral Diseases, Department of Orthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, China
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79
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Driessen AK, Devlin AC, Lundy FT, Martin SL, Sergeant GP, Mazzone SB, McGarvey LP. Perspectives on neuroinflammation contributing to chronic cough. Eur Respir J 2020; 56:13993003.00758-2020. [DOI: 10.1183/13993003.00758-2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 06/30/2020] [Indexed: 02/07/2023]
Abstract
Chronic cough can be a troublesome clinical problem. Current thinking is that increased activity and/or enhanced sensitivity of the peripheral and central neural pathways mediates chronic cough via processes similar to those associated with the development of chronic pain. While inflammation is widely thought to be involved in the development of chronic cough, the true mechanisms causing altered neural activity and sensitisation remain largely unknown. In this back-to-basics perspective article we explore evidence that inflammation in chronic cough may, at least in part, involve neuroinflammation orchestrated by glial cells of the nervous system. We summarise the extensive evidence for the role of both peripheral and central glial cells in chronic pain, and hypothesise that the commonalities between pain and cough pathogenesis and clinical presentation warrant investigations into the neuroinflammatory mechanisms that contribute to chronic cough. We open the debate that glial cells may represent an underappreciated therapeutic target for controlling troublesome cough in disease.
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80
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Korczeniewska OA, Khan J, Eliav E, Benoliel R. Molecular mechanisms of painful traumatic trigeminal neuropathy-Evidence from animal research and clinical correlates. J Oral Pathol Med 2020; 49:580-589. [PMID: 32557871 DOI: 10.1111/jop.13078] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 06/09/2020] [Indexed: 01/02/2023]
Abstract
Painful traumatic trigeminal neuropathy (PTTN) may occur following major craniofacial or oral trauma, or may be subsequent to relatively minor dental interventions. Following injury, pain may originate from a peripheral nerve, a ganglion, or from the central nervous system. In this review, we focus on molecular mechanisms of pain resulting from injury to the peripheral branch of the trigeminal nerve. This syndrome has been termed painful traumatic trigeminal neuropathy (PTTN) by the International Headache Society and replaces previous terms including atypical odontalgia, deafferentation pain, traumatic neuropathy and phantom toothache. We emphasize the scientific evidence supporting the events purported to lead to PTTN by reviewing the pathophysiology of PTTN based on relevant animal models. Additionally, we briefly overview clinical correlates and pathophysiological manifestations of PTTN.
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Affiliation(s)
- Olga A Korczeniewska
- Center for Orofacial Pain and Temporomandibular Disorders, Department of Diagnostic Sciences, Rutgers School of Dental Medicine, Rutgers, The State University of New Jersey, Newark, New Jersey, USA
| | - Junad Khan
- Eastman Institute of Oral Health, University of Rochester Medical Center, Rochester, New Jersey, USA
| | - Eli Eliav
- Eastman Institute of Oral Health, University of Rochester Medical Center, Rochester, New Jersey, USA
| | - Rafael Benoliel
- Center for Orofacial Pain and Temporomandibular Disorders, Department of Diagnostic Sciences, Rutgers School of Dental Medicine, Rutgers, The State University of New Jersey, Newark, New Jersey, USA
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81
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Litvin DG, Denstaedt SJ, Borkowski LF, Nichols NL, Dick TE, Smith CB, Jacono FJ. Peripheral-to-central immune communication at the area postrema glial-barrier following bleomycin-induced sterile lung injury in adult rats. Brain Behav Immun 2020; 87:610-633. [PMID: 32097765 PMCID: PMC8895345 DOI: 10.1016/j.bbi.2020.02.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 02/02/2020] [Accepted: 02/13/2020] [Indexed: 02/07/2023] Open
Abstract
The pathways for peripheral-to-central immune communication (P → C I-comm) following sterile lung injury (SLI) are unknown. SLI evokes systemic and central inflammation, which alters central respiratory control and viscerosensory transmission in the nucleus tractus solitarii (nTS). These functional changes coincide with increased interleukin-1 beta (IL-1β) in the area postrema, a sensory circumventricular organ that connects P → C I-comm to brainstem circuits that control homeostasis. We hypothesize that IL-1β and its downstream transcriptional target, cyclooxygenase-2 (COX-2), mediate P → C I-comm in the nTS. In a rodent model of SLI induced by intratracheal bleomycin (Bleo), the sigh frequency and duration of post-sigh apnea increased in Bleo- compared to saline- treated rats one week after injury. This SLI-dependent change in respiratory control occurred concurrently with augmented IL-1β and COX-2 immunoreactivity (IR) in the funiculus separans (FS), a barrier between the AP and the brainstem. At this barrier, increases in IL-1β and COX-2 IR were confined to processes that stained for glial fibrillary acidic protein (GFAP) and that projected basolaterally to the nTS. Further, FS radial-glia did not express TNF-α or IL-6 following SLI. To test our hypothesis, we blocked central COX-1/2 activity by intracerebroventricular (ICV) infusion of Indomethacin (Ind). Continuous ICV Ind treatment prevented Bleo-dependent increases in GFAP + and IL-1β + IR, and restored characteristics of sighs that reset the rhythm. These data indicate that changes in sighs following SLI depend partially on activation of a central COX-dependent P → C I-comm via radial-glia of the FS.
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Affiliation(s)
- David G Litvin
- Department of Physiology & Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States; Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States; Department of Fundamental Neuroscience, University of Lausanne, 1005 Lausanne, Switzerland
| | - Scott J Denstaedt
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States; Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI 48109, United States
| | - Lauren F Borkowski
- Department of Biomedical Sciences, University of Missouri College of Veterinary Medicine, Columbia, MO 65212, United States
| | - Nicole L Nichols
- Department of Biomedical Sciences, University of Missouri College of Veterinary Medicine, Columbia, MO 65212, United States
| | - Thomas E Dick
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States; Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States
| | - Corey B Smith
- Department of Physiology & Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States
| | - Frank J Jacono
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States; Division of Pulmonary, Critical Care and Sleep Medicine, Louis Stokes VA Medical Center, Cleveland, OH 44106, United States.
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82
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Yoshida S, Hagiwara Y, Tsuchiya M, Shinoda M, Koide M, Hatakeyama H, Chaweewannakorn C, Suzuki K, Yano T, Sogi Y, Itaya N, Sekiguchi T, Yabe Y, Sasaki K, Kanzaki M, Itoi E. Involvement of inflammasome activation via elevation of uric acid level in nociception in a mouse model of muscle pain. Mol Pain 2020; 15:1744806919858797. [PMID: 31161887 PMCID: PMC6614954 DOI: 10.1177/1744806919858797] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Muscle pain is a common condition in many diseases and is induced by muscle
overuse. Muscle overuse induces an increase in uric acid, which stimulates the
nucleotide-binding oligomerization domain-like receptor (NLR). This receptor
contains the pyrin domain NLRP-3 inflammasome which when activated, results in
the secretion of potent pro-inflammatory cytokines such as interleukin-1β
(IL-1β). The aim of this study was to investigate the involvement of
inflammasome activation via the elevation of uric acid level in nociception in a
mouse model of muscle pain. The right hind leg muscles of BALB/c mice were
stimulated electrically to induce excessive muscle contraction. The left hind
leg muscles were not stimulated as a control. Mechanical withdrawal thresholds,
levels of uric acid, IL-1β, and NLRP3, caspase-1 activity, and the number of
macrophages were investigated. Furthermore, the effects of xanthine oxidase
inhibitors, such as Brilliant Blue G, caspase-1 inhibitor, and clodronate
liposome, on pain were investigated. In the stimulated muscles, mechanical
withdrawal thresholds decreased, and the levels of uric acid, NLRP3, and IL-1β,
caspase-1 activity, and the number of macrophages increased compared to that in
the non-stimulated muscles. Administration of the inhibitors attenuated
hyperalgesia caused by excessive muscle contraction. These results suggested
that IL-1β secretion and NLRP3 inflammasome activation in macrophages produced
mechanical hyperalgesia by elevating uric acid level, and xanthine oxidase
inhibitors may potentially reduce over-exercised muscle pain.
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Affiliation(s)
- Shinichirou Yoshida
- 1 Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Yoshihiro Hagiwara
- 1 Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine, Sendai, Japan
| | | | - Masamichi Shinoda
- 3 Department of Physiology, Nihon University School of Dentistry, Tokyo, Japan
| | - Masashi Koide
- 4 Department of Orthopaedic Surgery, Matsuda Hospital, Sendai, Japan
| | - Hiroyasu Hatakeyama
- 5 Graduate School of Biomedical Engineering, Tohoku University, Sendai, Japan
| | | | - Kazuaki Suzuki
- 6 Department of Orthopaedic Surgery, JR Sendai Hospital, Sendai, Japan
| | - Toshihisa Yano
- 1 Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Yasuhito Sogi
- 1 Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Nobuyuki Itaya
- 6 Department of Orthopaedic Surgery, JR Sendai Hospital, Sendai, Japan
| | - Takuya Sekiguchi
- 7 Department of Orthopaedic Surgery, Iwate Prefectural Central Hospital, Morioka, Japan
| | - Yutaka Yabe
- 1 Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Keiichi Sasaki
- 8 Division of Advanced Prosthetic Dentistry, Tohoku University Graduate School of Dentistry, Sendai, Japan
| | - Makoto Kanzaki
- 5 Graduate School of Biomedical Engineering, Tohoku University, Sendai, Japan
| | - Eiji Itoi
- 1 Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine, Sendai, Japan
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83
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Neves AF, Farias FH, de Magalhães SF, Araldi D, Pagliusi M, Tambeli CH, Sartori CR, Lotufo CMDC, Parada CA. Peripheral Inflammatory Hyperalgesia Depends on P2X7 Receptors in Satellite Glial Cells. Front Physiol 2020; 11:473. [PMID: 32523543 PMCID: PMC7261868 DOI: 10.3389/fphys.2020.00473] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 04/17/2020] [Indexed: 12/23/2022] Open
Abstract
Peripheral inflammatory hyperalgesia depends on the sensitization of primary nociceptive neurons. Inflammation drives molecular alterations not only locally but also in the dorsal root ganglion (DRG) where interleukin-1 beta (IL-1β) and purinoceptors are upregulated. Activation of the P2X7 purinoceptors by ATP is essential for IL-1β maturation and release. At the DRG, P2X7R are expressed by satellite glial cells (SGCs) surrounding sensory neurons soma. Although SGCs have no projections outside the sensory ganglia these cells affect pain signaling through intercellular communication. Therefore, here we investigated whether activation of P2X7R by ATP and the subsequent release of IL-1β in DRG participate in peripheral inflammatory hyperalgesia. Immunofluorescent images confirmed the expression of P2X7R and IL-1β in SGCs of the DRG. The function of P2X7R was then verified using a selective antagonist, A-740003, or antisense for P2X7R administered in the L5-DRG. Inflammation was induced by CFA, carrageenan, IL-1β, or PGE2 administered in rat's hind paw. Blockage of P2X7R at the DRG reduced the mechanical hyperalgesia induced by CFA, and prevented the mechanical hyperalgesia induced by carrageenan or IL-1β, but not PGE2. It was also found an increase in P2X7 mRNA expression at the DRG after peripheral inflammation. IL-1β production was also increased by inflammatory stimuli in vivo and in vitro, using SGC-enriched cultures stimulated with LPS. In LPS-stimulated cultures, activation of P2X7R by BzATP induced the release of IL-1β, which was blocked by A-740003. In summary, our data suggest that peripheral inflammation leads to the activation of P2X7R expressed by SGCs at the DRG. Then, ATP-induced activation of P2X7R mediates the release of IL-1β from SGC. This evidence places the SGC as an active player in the establishment of peripheral inflammatory hyperalgesia and highlights the importance of the events in DRG for the treatment of inflammatory diseases.
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Affiliation(s)
- Amanda Ferreira Neves
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas, Campinas, Brazil
| | - Felipe Hertzing Farias
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas, Campinas, Brazil
| | | | - Dionéia Araldi
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas, Campinas, Brazil
| | - Marco Pagliusi
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas, Campinas, Brazil
| | - Claudia Herrera Tambeli
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas, Campinas, Brazil
| | - Cesar Renato Sartori
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas, Campinas, Brazil
| | | | - Carlos Amílcar Parada
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas, Campinas, Brazil
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Ni H, Xu M, Xie K, Fei Y, Deng H, He Q, Wang T, Liu S, Zhu J, Xu L, Yao M. Liquiritin Alleviates Pain Through Inhibiting CXCL1/CXCR2 Signaling Pathway in Bone Cancer Pain Rat. Front Pharmacol 2020; 11:436. [PMID: 32390832 PMCID: PMC7193085 DOI: 10.3389/fphar.2020.00436] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 03/20/2020] [Indexed: 01/06/2023] Open
Abstract
Bone cancer pain (BCP) is an intractable clinical problem, and lacked effective drugs for treating it. Recent research showed that several chemokines in the spinal cord are involved in the pathogenesis of BCP. In this study, the antinociceptive effects of liquiritin, which is an active component extracted from Glycyrrhizae Radix, were tested and the underlying mechanisms targeting spinal dorsal horn (SDH) were investigated. The BCP group displayed a significant decrease in the mechanical withdrawal threshold on days 6, 12, and 18 when compared with sham groups. Intrathecal administration of different doses of liquiritin alleviated mechanical allodynia in BCP rats. The results of immunofluorescent staining and western blotting showed that liquiritin inhibited BCP-induced activation of astrocytes in the spinal cord. Moreover, intrathecal administration of liquiritin effectively inhibited the activation of CXCL1/CXCR2 signaling pathway and production of IL-1β and IL-17 in BCP rats. In astroglial-enriched cultures, Lipopolysaccharides (LPS) elicited the release of chemokine CXCL1, and the release was decreased in a dose-dependent manner by liquiritin. In primary neurons, liquiritin indirectly reduced the increase of CXCR2 by astroglial-enriched-conditioned medium but not directly on the CXCR2 target site. These results suggested that liquiritin effectively attenuated BCP in rats by inhibiting the activation of spinal astrocytic CXCL1 and neuronal CXCR2 pathway. These findings provided evidence regarding the the antinociceptive effect of liquiritin on BCP.
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Affiliation(s)
- Huadong Ni
- Department of Anesthesiology and Pain Research Center, The Affiliated Hospital of Jiaxing University, Jiaxing, China
| | - Miao Xu
- Department of Anesthesiology and Pain Research Center, The Affiliated Hospital of Jiaxing University, Jiaxing, China
| | - Keyue Xie
- Department of Anesthesiology and Pain Research Center, The Affiliated Hospital of Jiaxing University, Jiaxing, China
| | - Yong Fei
- Department of Anesthesiology and Pain Research Center, The Affiliated Hospital of Jiaxing University, Jiaxing, China
| | - Housheng Deng
- Department of Anesthesiology and Pain Research Center, The Affiliated Hospital of Jiaxing University, Jiaxing, China
| | - Qiuli He
- Department of Anesthesiology and Pain Research Center, The Affiliated Hospital of Jiaxing University, Jiaxing, China
| | - Tingting Wang
- Department of Anesthesiology and Pain Research Center, The Affiliated Hospital of Jiaxing University, Jiaxing, China
| | - Songlei Liu
- Department of Anesthesiology and Pain Research Center, The Affiliated Hospital of Jiaxing University, Jiaxing, China
| | - Jianjun Zhu
- Department of Anesthesiology and Pain Research Center, The Affiliated Hospital of Jiaxing University, Jiaxing, China
| | - Longsheng Xu
- Department of Anesthesiology and Pain Research Center, The Affiliated Hospital of Jiaxing University, Jiaxing, China
| | - Ming Yao
- Department of Anesthesiology and Pain Research Center, The Affiliated Hospital of Jiaxing University, Jiaxing, China
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85
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Myelopathy and Reactive Microgliosis and Astrogliosis in Equine Back Pain. J Equine Vet Sci 2020; 90:103019. [PMID: 32534783 DOI: 10.1016/j.jevs.2020.103019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 04/02/2020] [Accepted: 04/02/2020] [Indexed: 01/25/2023]
Abstract
Equine chronic back pain (CBP) has been linked to different pathologic processes, which directly or indirectly involve spinal structures. Thus, making diagnosis and management very challenging with most horses with the condition recommended for early retirement from athletic activity. This study described the spinal cord lesions and the development of reactive microgliosis and astrocytosis in the spinal cords of horse with CBP. Thoracolumbar spinal cord segments from three horses euthanized because of unresolved CBP were dissected and grossly and histopathologically examined. The expression of activated microglia and astrocytes were demonstrated immunohistochemically using polyclonal rabbit anti-Iba-1 and anti-glial fibrillary acidic protein antibodies, respectively. All horses had radiological evidence of varying degrees of kissing spine involving six to nine vertebrae with the majority of the lesions graded between 2 and 5. Grossly, there was myelomalacia with intramedullary hemorrhages. The gray matters of the spinal cords were characterized by hemorrhagic malacic lesions with medullary disintegration. Reactive microgliosis and astrocytosis were evident in the spinal dorsal horns. White matter lesions include axonal swollen and/or loss, satellitosis, and varying degrees of dilation of myelin sheaths with some containing macrophages. In conclusion, the presence of reactive microgliosis and astrogliosis in the spinal dorsal horn indicates that they are possible precipitating factors in the development of equine CBP.
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86
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Lim JSY, Kam PCA. Neuroimmune mechanisms of pain: Basic science and potential therapeutic modulators. Anaesth Intensive Care 2020; 48:167-178. [DOI: 10.1177/0310057x20902774] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
This narrative review aims to describe the role of peripheral and central immune responses to tissue and nerve damage in animal models, and to discuss the use of immunomodulatory agents in clinical practice and their perioperative implications. Animal models of pain have demonstrated that nerve injury activates immune signalling pathways that drive aberrant sensory processes, resulting in neuropathic and chronic pain. This response involves the innate immune system. T lymphocytes are also recruited. Glial cells surrounding the damaged nerves release cytokines and proinflammatory mediators that activate resident immune cells and recruit circulatory immune cells. Toll-like receptors on the glial cells play a crucial role in the pathogenesis of chronic pain. Animal models indicate an immune mechanism of neuropathic pain. Analgesic drugs and anaesthetic agents have varied effects on the neuroimmune interface. Evidence of a neuroimmune interaction is mainly from animal studies. Human studies are required to evaluate the clinical implications of this neuroimmune interaction.
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Affiliation(s)
- Jessica SY Lim
- Department of Anaesthetics, Royal Prince Alfred Hospital, Sydney, Australia
| | - Peter CA Kam
- Department of Anaesthetics, Royal Prince Alfred Hospital, Sydney, Australia
- Discipline of Anaesthesia, Central Clinical School, Faculty of Medicine and Health, University of Sydney, Sydney, Australia
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87
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Hossain MZ, Ando H, Unno S, Kitagawa J. Targeting Peripherally Restricted Cannabinoid Receptor 1, Cannabinoid Receptor 2, and Endocannabinoid-Degrading Enzymes for the Treatment of Neuropathic Pain Including Neuropathic Orofacial Pain. Int J Mol Sci 2020; 21:E1423. [PMID: 32093166 PMCID: PMC7073137 DOI: 10.3390/ijms21041423] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 02/17/2020] [Accepted: 02/18/2020] [Indexed: 02/06/2023] Open
Abstract
Neuropathic pain conditions including neuropathic orofacial pain (NOP) are difficult to treat. Contemporary therapeutic agents for neuropathic pain are often ineffective in relieving pain and are associated with various adverse effects. Finding new options for treating neuropathic pain is a major priority in pain-related research. Cannabinoid-based therapeutic strategies have emerged as promising new options. Cannabinoids mainly act on cannabinoid 1 (CB1) and 2 (CB2) receptors, and the former is widely distributed in the brain. The therapeutic significance of cannabinoids is masked by their adverse effects including sedation, motor impairment, addiction and cognitive impairment, which are thought to be mediated by CB1 receptors in the brain. Alternative approaches have been developed to overcome this problem by selectively targeting CB2 receptors, peripherally restricted CB1 receptors and endocannabinoids that may be locally synthesized on demand at sites where their actions are pertinent. Many preclinical studies have reported that these strategies are effective for treating neuropathic pain and produce no or minimal side effects. Recently, we observed that inhibition of degradation of a major endocannabinoid, 2-arachydonoylglycerol, can attenuate NOP following trigeminal nerve injury in mice. This review will discuss the above-mentioned alternative approaches that show potential for treating neuropathic pain including NOP.
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Affiliation(s)
- Mohammad Zakir Hossain
- Department of Oral Physiology, School of Dentistry, Matsumoto Dental University, 1780 Gobara Hirooka, Shiojiri, Nagano 399-0781, Japan; (S.U.); (J.K.)
| | - Hiroshi Ando
- Department of Biology, School of Dentistry, Matsumoto Dental University, 1780 Gobara, Hirooka, Shiojiri, Nagano 399-0781, Japan;
| | - Shumpei Unno
- Department of Oral Physiology, School of Dentistry, Matsumoto Dental University, 1780 Gobara Hirooka, Shiojiri, Nagano 399-0781, Japan; (S.U.); (J.K.)
| | - Junichi Kitagawa
- Department of Oral Physiology, School of Dentistry, Matsumoto Dental University, 1780 Gobara Hirooka, Shiojiri, Nagano 399-0781, Japan; (S.U.); (J.K.)
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88
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Cernit V, Sénécal J, Othman R, Couture R. Reciprocal Regulatory Interaction between TRPV1 and Kinin B1 Receptor in a Rat Neuropathic Pain Model. Int J Mol Sci 2020; 21:ijms21030821. [PMID: 32012798 PMCID: PMC7037982 DOI: 10.3390/ijms21030821] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 01/21/2020] [Accepted: 01/22/2020] [Indexed: 12/13/2022] Open
Abstract
Kinins are mediators of pain and inflammation and evidence suggests that the inducible kinin B1 receptor (B1R) is involved in neuropathic pain (NP). This study investigates whether B1R and TRPV1 are colocalized on nociceptors and/or astrocytes to enable regulatory interaction either directly or through the cytokine pathway (IL-1β, TNF-α) in NP. Sprague Dawley rats were subjected to unilateral partial sciatic nerve ligation (PSNL) and treated from 14 to 21 days post-PSNL with antagonists of B1R (SSR240612, 10 mg·kg-1, i.p.) or TRPV1 (SB366791, 1 mg·kg-1, i.p.). The impact of these treatments was assessed on nociceptive behavior and mRNA expression of B1R, TRPV1, TNF-α, and IL-1β. Localization on primary sensory fibers, astrocytes, and microglia was determined by immunofluorescence in the lumbar spinal cord and dorsal root ganglion (DRG). Both antagonists suppressed PSNL-induced thermal hyperalgesia, but only SB366791 blunted mechanical and cold allodynia. SSR240612 reversed PSNL-induced enhanced protein and mRNA expression of B1R and TRPV1 mRNA levels in spinal cord while SB366791 further increased B1R mRNA/protein expression. B1R and TRPV1 were found in non-peptide sensory fibers and astrocytes, and colocalized in the spinal dorsal horn and DRG, notably with IL-1β on astrocytes. IL-1β mRNA further increased under B1R or TRPV1 antagonism. Data suggest that B1R and TRPV1 contribute to thermal hyperalgesia and play a distinctive role in allodynia associated with NP. Close interaction and reciprocal regulatory mechanism are suggested between B1R and TRPV1 on astrocytes and nociceptors in NP.
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89
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Martins DO, Marques DP, Venega RAG, Chacur M. Photobiomodulation and B vitamins administration produces antinociception in an orofacial pain model through the modulation of glial cells and cytokines expression. Brain Behav Immun Health 2020; 2:100040. [PMID: 34589831 PMCID: PMC8474295 DOI: 10.1016/j.bbih.2020.100040] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 01/21/2020] [Accepted: 01/24/2020] [Indexed: 12/15/2022] Open
Abstract
Chronic constriction injury (CCI) of infraorbital nerve (IoN) results in whisker pad mechanical allodynia in rats and activation glial cells contributing to the development of orofacial pain. Whisker pad mechanical allodynia (von Frey stimuli) was tested pre and postoperatively and conducted during the treatment time. Photobiomodulation (PBM) and vitamins B complex (VBC) has been demonstrated therapeutic efficacy in ameliorate neuropathic pain. The aim of this study was to evaluate the antinociceptive effect of PBM, VBC or the combined treatment VBC + PBM on orofacial pain due to CCI-IoN. Behavioral and molecular approaches were used to analyses nociception, cellular and neurochemical alterations. CCI-IoN caused mechanical allodynia and cellular alterations including increased expression of glial fibrillary acid protein (GFAP) and ionized calcium binding adaptor molecule 1 (Iba-1), administration of VBC (B1/B6/B12 at 180/180/1.8 mg/kg, s.c., 5 times all long 10 sessions) and PBM therapy (904 nm, power of 75Wpico, average power of 0.0434 W, pulse frequency of 9500 Hz, area of the beam 0.13 cm2, 18 s duration, energy density 6 J/cm2, with an energy per point of 0.78 J for 10 sessions) or their combination presented improvement of the nociceptive behavior and decreased expression of GFAP and Iba-1. Additionally, CCI-IoN rats exhibited an upregulation of IL1β, IL6 and TNF-α expression and all treatments prevented this upregulation and also increased IL10 expression. Overall, the present results highlight the pain reliever effect of VBC or PBM alone or in combination, through the modulation of glial cells and cytokines expression in the spinal trigeminal nucleus of rats.
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Affiliation(s)
- D O Martins
- Department of Anatomy, Laboratory of Functional Neuroanatomy of Pain, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes, 2415, SP, Brazil
| | - D P Marques
- Department of Anatomy, Laboratory of Functional Neuroanatomy of Pain, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes, 2415, SP, Brazil
| | - R A G Venega
- Department of Anatomy, Laboratory of Functional Neuroanatomy of Pain, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes, 2415, SP, Brazil
| | - M Chacur
- Department of Anatomy, Laboratory of Functional Neuroanatomy of Pain, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes, 2415, SP, Brazil
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90
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Barkhordarian A, Demerjian G, Chiappelli F. Translational research of temporomandibular joint pathology: a preliminary biomarker and fMRI study. J Transl Med 2020; 18:22. [PMID: 31931814 PMCID: PMC6956559 DOI: 10.1186/s12967-019-02202-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 12/30/2019] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND The temporomandibular joint (TMJ) is well innervated by braches of the trigeminal nerve. The temporomandibular joint disorders (TMD) can cause neural-inflammation in the peripheral nervous system (PNS) at the site of injury, or compression, and may have systemic effects on the central nervous system (CNS). Neural-inflammation causes elevations in cytokine expression and microglia activation. When the site of injury, or compression is treated, or relieved, neural inflammation is reduced. These changes can be seen and measured with fMRI brain activities. METHODS For this study, patients with comorbid TMD and systemic/neurologic conditions were compared using clinical diagnostic markers, inflammatory, pain, tissue destruction enzymatic biomarkers, and functional magnetic resonance imaging (fMRI) activity of the brain, with and without a custom-made dental orthotic. RESULTS Our results showed a correlation between the clinical diagnosis of the pathological TMJ, biomarkers and the fMRI study. There was a marked elevation of biomarkers in samples taken from TMJ of patients who were clinically diagnosed with TMD. The fMRI study of TMD patients showed an abnormal hyper-connected salience network and a diminished blood flow to the anterior frontal lobes when they did not wear their customized dental orthotics. CONCLUSIONS Our findings highlight the importance of TMJ-CNS connections and use of fMRI as an investigative tool for understanding TMD and its related neurological pathologies.
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Affiliation(s)
- Andre Barkhordarian
- University of California Los Angeles, School of Dentistry, Division of Oral Biology and Medicine, Los Angeles, USA.
| | - Gary Demerjian
- University of California Los Angeles, School of Dentistry, Division of Oral Biology and Medicine, Los Angeles, USA
| | - Francesco Chiappelli
- University of California Los Angeles, School of Dentistry, Division of Oral Biology and Medicine, Los Angeles, USA
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91
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Oh JY, Hwang TY, Jang JH, Park JY, Ryu Y, Lee H, Park HJ. Muscovite nanoparticles mitigate neuropathic pain by modulating the inflammatory response and neuroglial activation in the spinal cord. Neural Regen Res 2020; 15:2162-2168. [PMID: 32394976 PMCID: PMC7716045 DOI: 10.4103/1673-5374.282260] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Despite numerous efforts to overcome neuropathic pain, various pharmacological drugs often fail to meet the needs and have many side effects. Muscovite is an aluminosilicate mineral that has been reported to have an anti-inflammatory effect, but the efficacy of muscovite for neuropathic pain has not been investigated. Here, we assessed whether muscovite nanoparticles can reduce the symptoms of pain by controlling the inflammatory process observed in neuropathic pain. The analgesic effects of muscovite nanoparticles were explored using partial sciatic nerve ligation model of neuropathic pain, in which one-third to one-half of the nerve trifurcation of the sciatic nerve was tightly tied to the dorsal side. Muscovite nanoparticles (4 mg/100 μL) was given intramuscularly to evaluate its effects on neuropathic pain (3 days per week for 4 weeks). The results showed that the muscovite nanoparticle injections significantly alleviated partial sciatic nerve ligation-induced mechanical and cold allodynia. In the spinal cord, the muscovite nanoparticle injections exhibited inhibitory effects on astrocyte and microglia activation and reduced the expression of pro-inflammatory cytokines, such as interleukin-1β, tumor necrosis factor-α, interleiukin-6 and monocyte chemoattractant protein-1, which were upregulated in the partial sciatic nerve ligation model. Moreover, the muscovite nanoparticle injections resulted in a decrease in activating transcription factor 3, a neuronal injury marker, in the sciatic nerve. These results suggest that the analgesic effects of muscovite nanoparticle on partial sciatic nerve ligation-induced neuropathic pain may result from inhibiting activation of astrocytes and microglia as well as pro-inflammatory cytokines. We propose that muscovite nanoparticle is a potential anti-nociceptive candidate for neuropathic pain. All experimental protocols in this study were approved by the Institutional Animal Ethics Committee (IACUC) at Dongguk University, South Korea (approval No. 2017-022-1) on September 28, 2017.
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Affiliation(s)
- Ju-Young Oh
- Acupuncture and Meridian Science Research Center, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu; Department of Korean Medical Science, Graduate School of Korean Medicine; BK21 PLUS Korean Medicine Science Center, College of Korean Medicine, Kyung Hee University, Seoul, Republic of Korea
| | - Tae-Yeon Hwang
- Acupuncture and Meridian Science Research Center, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu; Department of Korean Medical Science, Graduate School of Korean Medicine; BK21 PLUS Korean Medicine Science Center, College of Korean Medicine, Kyung Hee University, Seoul, Republic of Korea
| | - Jae-Hwan Jang
- Acupuncture and Meridian Science Research Center, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu; Department of Korean Medical Science, Graduate School of Korean Medicine; BK21 PLUS Korean Medicine Science Center, College of Korean Medicine, Kyung Hee University, Seoul, Republic of Korea
| | - Ji-Yeun Park
- Acupuncture and Meridian Science Research Center, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul; College of Korean Medicine, Daejeon University, Daejeon, Republic of Korea
| | - Yeonhee Ryu
- Korean Institute of Oriental Medicine, Daejeon, Republic of Korea
| | - HyeJung Lee
- Acupuncture and Meridian Science Research Center, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu; Department of Korean Medical Science, Graduate School of Korean Medicine, Kyung Hee University, Seoul, Republic of Korea
| | - Hi-Joon Park
- Acupuncture and Meridian Science Research Center, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu; Department of Korean Medical Science, Graduate School of Korean Medicine; BK21 PLUS Korean Medicine Science Center, College of Korean Medicine, Kyung Hee University, Seoul, Republic of Korea
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Dichotomic effects of clinically used drugs on tumor growth, bone remodeling and pain management. Sci Rep 2019; 9:20155. [PMID: 31882872 PMCID: PMC6934511 DOI: 10.1038/s41598-019-56622-5] [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] [Received: 04/10/2019] [Accepted: 12/12/2019] [Indexed: 11/08/2022] Open
Abstract
Improvements in the survival of breast cancer patients have led to the emergence of bone health and pain management as key aspects of patient’s quality of life. Here, we used a female rat MRMT-1 model of breast cancer-induced bone pain to compare the effects of three drugs used clinically morphine, nabilone and zoledronate on tumor progression, bone remodeling and pain relief. We found that chronic morphine reduced the mechanical hypersensitivity induced by the proliferation of the luminal B aggressive breast cancer cells in the tumor-bearing femur and prevented spinal neuronal and astrocyte activation. Using MTT cell viability assay and MRI coupled to 18FDG PET imaging followed by ex vivo 3D µCT, we further demonstrated that morphine did not directly exert tumor growth promoting or inhibiting effects on MRMT-1 cancer cells but induced detrimental effects on bone healing by disturbing the balance between bone formation and breakdown. In sharp contrast, both the FDA-approved bisphosphonate zoledronate and the synthetic cannabinoid nabilone prescribed as antiemetics to patients receiving chemotherapy were effective in limiting the osteolytic bone destruction, thus preserving the bone architecture. The protective effect of nabilone on bone metabolism was further accompanied by a direct inhibition of tumor growth. As opposed to zoledronate, nabilone was however not able to manage bone tumor-induced pain and reactive gliosis. Altogether, our results revealed that morphine, nabilone and zoledronate exert disparate effects on tumor growth, bone metabolism and pain control. These findings also support the use of nabilone as an adjuvant therapy for bone metastases.
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The gap junction inhibitor INI-0602 attenuates mechanical allodynia and depression-like behaviors induced by spared nerve injury in rats. Neuroreport 2019; 30:369-377. [PMID: 30741784 DOI: 10.1097/wnr.0000000000001209] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Gap junctions (GJs) are novel molecular targets for pain therapeutics due to their pain-promoting function. INI-0602, a new GJ inhibitor, exerts a neuroprotective role, while its role in neuropathic pain is unclear. The objective was to investigate the analgesic role and mechanisms of INI-0602 in neuropathic pain induced by spared nerve injury (SNI), and whether INI-0602 attenuated pain-induced depression-like behaviors. Rats were randomly assigned to saline treatment groups (sham+NS and SNI+NS) or INI-0602 treatment groups (sham+INI-0602 and SNI+INI-0602). The von Frey test was used to assess pain behavior, and the sucrose preference test, the forced swimming test, and the tail suspension test were used to assess depression-like behaviors. Gap junction intercellular communication (GJIC) was measured by parachute assay. Western blots were used to determine the protein expression. In vitro, INI-0602 significantly suppressed GJIC by decreasing connexin43 and connexin32 expression. In vivo, INI-0602 significantly suppressed mechanical allodynia during initiation (7 days after SNI) and the maintenance phase (21 days after SNI) and simultaneously attenuated accompanying depression-like behaviors. Furthermore, INI-0602 markedly suppressed the activation of astrocytes and microglia on days 7 and 21 by reducing GJIC. Finally, INI-0602 reversed the changes in the brain-derived neurotrophic factor and Nr2b subunits of the N-methyl-D-aspartate receptor in SNI rats, suggesting that these effects of INI-0602 were related to its analgesic effect. Our findings demonstrated that blocking GJs with INI-0602 attenuated mechanical pain hypersensitivity and related depression-like behaviors in SNI rats by reducing glial activation.
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Zhang YY, Song N, Liu F, Lin J, Liu MK, Huang CL, Liao DQ, Zhou C, Wang H, Shen JF. Activation of the RAS/B-RAF-MEK-ERK pathway in satellite glial cells contributes to substance p-mediated orofacial pain. Eur J Neurosci 2019; 51:2205-2218. [PMID: 31705725 DOI: 10.1111/ejn.14619] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2019] [Revised: 10/11/2019] [Accepted: 11/01/2019] [Indexed: 02/06/2023]
Abstract
The cross talk between trigeminal ganglion (TG) neurons and satellite glial cells (SGCs) is crucial for the regulation of inflammatory orofacial pain. Substance P (SP) plays an important role by activating neurokinin (NK)-I receptors in this cross talk. The activation of extracellular signal-regulated kinase (ERK) 1/2, protein kinase A (PKA) and protein kinase C (PKC) in neurons and SGCs of peripheral ganglions by peripheral inflammation is associated with inflammatory hypersensitivity. This study tested the hypothesis that SP evoked SP-NK-I receptor positive feedback via the Renin-Angiotensin System/B-Protein Kinase A-Rapidly Accelerates Fibrosarcoma-MEK-Extracellular Signal-Regulated Kinase (RAS/PKA-RAF-MEK-ERK) pathway, which is involved in pain hypersensitivity. Inflammatory models were induced in vivo by injecting Complete Freund's adjuvant (CFA) into the whisker pad of rats. SP was administrated to SGCs in vitro for investigating, whether SP regulates the expression of NK-I receptor in the SGC nucleus. The effects of RAS-RAF-MEK, PKA and PKC pathways in this process were measured by co-incubating SGCs with respective Raf, PKA, PKC and MEK inhibitors in vitro and by pre-injecting these inhibitors into the TG in vivo. SP significantly upregulated NK-I receptor, p-ERK1/2, Ras, B-Raf, PKA and PKC in SGCs under inflammatory conditions. In addition, L703,606 (NK-I receptor antagonist), U0126 (MEK inhibitor), Sorafenib (Raf inhibitor) and H892HCL (PKA inhibitor) but not chelerythrine chloride (PKC inhibitor) significantly decreased NK-I mRNA and protein levels induced by SP. The allodynia-related behavior evoked by CFA was inhibited by pre-injection of L703,606, U0126, Sorafenib and H892HCL into the TG. Overall, SP upregulates NK-I receptor in TG SGCs via PKA/RAS-RAF-MEK-ERK pathway activation, contributing to a positive feedback of SP-NK-I receptor in inflammatory orofacial pain.
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Affiliation(s)
- Yan-Yan Zhang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Ning Song
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Fei Liu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Jiu Lin
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Meng-Ke Liu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Chao-Lan Huang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Da-Qing Liao
- Laboratory of Anesthesia and Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu, China
| | - Cheng Zhou
- Laboratory of Anesthesia and Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu, China
| | - Hang Wang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Jie-Fei Shen
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
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Mirabelli E, Ni L, Li L, Acioglu C, Heary RF, Elkabes S. Pathological pain processing in mouse models of multiple sclerosis and spinal cord injury: contribution of plasma membrane calcium ATPase 2 (PMCA2). J Neuroinflammation 2019; 16:207. [PMID: 31703709 PMCID: PMC6839084 DOI: 10.1186/s12974-019-1585-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 09/10/2019] [Indexed: 12/17/2022] Open
Abstract
Background Neuropathic pain is often observed in individuals with multiple sclerosis (MS) and spinal cord injury (SCI) and is not adequately alleviated by current pharmacotherapies. A better understanding of underlying mechanisms could facilitate the discovery of novel targets for therapeutic interventions. We previously reported that decreased plasma membrane calcium ATPase 2 (PMCA2) expression in the dorsal horn (DH) of healthy PMCA2+/− mice is paralleled by increased sensitivity to evoked nociceptive pain. These studies suggested that PMCA2, a calcium extrusion pump expressed in spinal cord neurons, plays a role in pain mechanisms. However, the contribution of PMCA2 to neuropathic pain processing remains undefined. The present studies investigated the role of PMCA2 in neuropathic pain processing in the DH of wild-type mice affected by experimental autoimmune encephalomyelitis (EAE), an animal model of MS, and following SCI. Methods EAE was induced in female and male C57Bl/6N mice via inoculation with myelin oligodendrocyte glycoprotein fragment 35–55 (MOG35–55) emulsified in Complete Freund’s Adjuvant (CFA). CFA-inoculated mice were used as controls. A severe SC contusion injury was induced at thoracic (T8) level in female C57Bl/6N mice. Pain was evaluated by the Hargreaves and von Frey filament tests. PMCA2 levels in the lumbar DH were analyzed by Western blotting. The effectors that decrease PMCA2 expression were identified in SC neuronal cultures. Results Increased pain in EAE and SCI was paralleled by a significant decrease in PMCA2 levels in the DH. In contrast, PMCA2 levels remained unaltered in the DH of mice with EAE that manifested motor deficits but not increased pain. Interleukin-1β (IL-1β), tumor necrosis factor α (TNFα), and IL-6 expression were robustly increased in the DH of mice with EAE manifesting pain, whereas these cytokines showed a modest increase or no change in mice with EAE in the absence of pain. Only IL-1β decreased PMCA2 levels in pure SC neuronal cultures through direct actions. Conclusions PMCA2 is a contributor to neuropathic pain mechanisms in the DH. A decrease in PMCA2 in DH neurons is paralleled by increased pain sensitivity, most likely through perturbations in calcium signaling. Interleukin-1β is one of the effectors that downregulates PMCA2 by acting directly on neurons.
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Affiliation(s)
- Ersilia Mirabelli
- The Reynolds Family Spine Laboratory, Department of Neurosurgery, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, 07103, USA.,School of Graduate Studies, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, 07103, USA
| | - Li Ni
- The Reynolds Family Spine Laboratory, Department of Neurosurgery, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, 07103, USA
| | - Lun Li
- The Reynolds Family Spine Laboratory, Department of Neurosurgery, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, 07103, USA
| | - Cigdem Acioglu
- The Reynolds Family Spine Laboratory, Department of Neurosurgery, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, 07103, USA
| | - Robert F Heary
- The Reynolds Family Spine Laboratory, Department of Neurosurgery, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, 07103, USA.,School of Graduate Studies, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, 07103, USA
| | - Stella Elkabes
- The Reynolds Family Spine Laboratory, Department of Neurosurgery, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, 07103, USA. .,School of Graduate Studies, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, 07103, USA.
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96
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Abstract
Astrocytes are critical for maintaining the homeostasis of the CNS. Increasing evidence suggests that a number of neurological and neuropsychiatric disorders, including chronic pain, may result from astrocyte 'gliopathy'. Indeed, in recent years there has been substantial progress in our understanding of how astrocytes can regulate nociceptive synaptic transmission via neuronal-glial and glial-glial cell interactions, as well as the involvement of spinal and supraspinal astrocytes in the modulation of pain signalling and the maintenance of neuropathic pain. A role of astrocytes in the pathogenesis of chronic itch is also emerging. These developments suggest that targeting the specific pathways that are responsible for astrogliopathy may represent a novel approach to develop therapies for chronic pain and chronic itch.
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97
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Transfer of complex regional pain syndrome to mice via human autoantibodies is mediated by interleukin-1-induced mechanisms. Proc Natl Acad Sci U S A 2019; 116:13067-13076. [PMID: 31182576 DOI: 10.1073/pnas.1820168116] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Neuroimmune interactions may contribute to severe pain and regional inflammatory and autonomic signs in complex regional pain syndrome (CRPS), a posttraumatic pain disorder. Here, we investigated peripheral and central immune mechanisms in a translational passive transfer trauma mouse model of CRPS. Small plantar skin-muscle incision was performed in female C57BL/6 mice treated daily with purified serum immunoglobulin G (IgG) from patients with longstanding CRPS or healthy volunteers followed by assessment of paw edema, hyperalgesia, inflammation, and central glial activation. CRPS IgG significantly increased and prolonged swelling and induced stable hyperalgesia of the incised paw compared with IgG from healthy controls. After a short-lasting paw inflammatory response in all groups, CRPS IgG-injected mice displayed sustained, profound microglia and astrocyte activation in the dorsal horn of the spinal cord and pain-related brain regions, indicating central sensitization. Genetic deletion of interleukin-1 (IL-1) using IL-1αβ knockout (KO) mice and perioperative IL-1 receptor type 1 (IL-1R1) blockade with the drug anakinra, but not treatment with the glucocorticoid prednisolone, prevented these changes. Anakinra treatment also reversed the established sensitization phenotype when initiated 8 days after incision. Furthermore, with the generation of an IL-1β floxed(fl/fl) mouse line, we demonstrated that CRPS IgG-induced changes are in part mediated by microglia-derived IL-1β, suggesting that both peripheral and central inflammatory mechanisms contribute to the transferred disease phenotype. These results indicate that persistent CRPS is often contributed to by autoantibodies and highlight a potential therapeutic use for clinically licensed antagonists, such as anakinra, to prevent or treat CRPS via blocking IL-1 actions.
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98
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Sphingosine-1-phosphate receptor 1 activation in astrocytes contributes to neuropathic pain. Proc Natl Acad Sci U S A 2019; 116:10557-10562. [PMID: 31068460 DOI: 10.1073/pnas.1820466116] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Neuropathic pain afflicts millions of individuals and represents a major health problem for which there is limited effective and safe therapy. Emerging literature links altered sphingolipid metabolism to nociceptive processing. However, the neuropharmacology of sphingolipid signaling in the central nervous system in the context of chronic pain remains largely unexplored and controversial. We now provide evidence that sphingosine-1-phosphate (S1P) generated in the dorsal horn of the spinal cord in response to nerve injury drives neuropathic pain by selectively activating the S1P receptor subtype 1 (S1PR1) in astrocytes. Accordingly, genetic and pharmacological inhibition of S1PR1 with multiple antagonists in distinct chemical classes, but not agonists, attenuated and even reversed neuropathic pain in rodents of both sexes and in two models of traumatic nerve injury. These S1PR1 antagonists retained their ability to inhibit neuropathic pain during sustained drug administration, and their effects were independent of endogenous opioid circuits. Moreover, mice with astrocyte-specific knockout of S1pr1 did not develop neuropathic pain following nerve injury, thereby identifying astrocytes as the primary cellular substrate of S1PR1 activity. On a molecular level, the beneficial reductions in neuropathic pain resulting from S1PR1 inhibition were driven by interleukin 10 (IL-10), a potent neuroprotective and anti-inflammatory cytokine. Collectively, our results provide fundamental neurobiological insights that identify the cellular and molecular mechanisms engaged by the S1PR1 axis in neuropathic pain and establish S1PR1 as a target for therapeutic intervention with S1PR1 antagonists as a class of nonnarcotic analgesics.
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99
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Albrecht DS, Mainero C, Ichijo E, Ward N, Granziera C, Zürcher NR, Akeju O, Bonnier G, Price J, Hooker JM, Napadow V, Loggia ML, Hadjikhani N. Imaging of neuroinflammation in migraine with aura: A [ 11C]PBR28 PET/MRI study. Neurology 2019; 92:e2038-e2050. [PMID: 30918090 DOI: 10.1212/wnl.0000000000007371] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 01/07/2019] [Indexed: 12/12/2022] Open
Abstract
OBJECTIVE To determine if migraine with aura is associated with neuroinflammation, which has been suggested by preclinical models of cortical spreading depression (CSD) as well as imaging of human pain conditions. METHODS Thirteen migraineurs with aura and 16 healthy controls received integrated PET/MRI brain scans with [11C]PBR28, a radioligand that binds to the 18 kDa translocator protein, a marker of glial activation. Standardized uptake value ratio (SUVR) was compared between groups, and regressed against clinical variables, using region of interest and whole-brain voxelwise analyses. RESULTS Compared to healthy controls, migraineurs demonstrated SUVR elevations in nociceptive processing areas (e.g., thalamus and primary/secondary somatosensory and insular cortices) as well as in areas previously shown to be involved in CSD generation (visual cortex). SUVR levels in frontoinsular cortex, primary/secondary somatosensory cortices, and basal ganglia were correlated with frequency of migraine attacks. CONCLUSIONS These findings demonstrate that migraine with aura is associated with neuroimmune activation/neuroinflammation, and support a possible link between CSD and glial activation, previously observed in animals.
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Affiliation(s)
- Daniel S Albrecht
- From the A.A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown
| | - Caterina Mainero
- From the A.A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown
| | - Eri Ichijo
- From the A.A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown
| | - Noreen Ward
- From the A.A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown
| | - Cristina Granziera
- From the A.A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown
| | - Nicole R Zürcher
- From the A.A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown
| | - Oluwaseun Akeju
- From the A.A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown
| | - Guillaume Bonnier
- From the A.A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown
| | - Julie Price
- From the A.A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown
| | - Jacob M Hooker
- From the A.A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown
| | - Vitaly Napadow
- From the A.A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown
| | - Marco L Loggia
- From the A.A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown
| | - Nouchine Hadjikhani
- From the A.A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown.
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Siouti E, Andreakos E. The many facets of macrophages in rheumatoid arthritis. Biochem Pharmacol 2019; 165:152-169. [PMID: 30910693 DOI: 10.1016/j.bcp.2019.03.029] [Citation(s) in RCA: 136] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 03/19/2019] [Indexed: 12/24/2022]
Abstract
Macrophages are central to the pathophysiology of rheumatoid arthritis (RA). They constitute the main source of pro-inflammatory cytokines and chemokines such as TNF and IL-1β, they activate a wide range of immune and non-immune cells, and they secrete diverse tissue degrading enzymes driving chronic pro-inflammatory, tissue destructive and pain responses in RA. However, they can also produce anti-inflammatory cytokines such as IL-10, secrete inhibitors of tissue degrading enzymes and promote immunoregulatory and protective responses, suggesting the existence of macrophages with distinct and diverse functional activities. Although the underlying basis of this phenomenon has remained obscure for years, emerging evidence has now provided insight into the mechanisms and molecular processes involved. Here, we review current knowledge on the biology of macrophages in RA, and highlight recent literature on the heterogeneity, origins and ontogeny of macrophages as part of the mononuclear phagocyte system. We also discuss their plasticity in the context of the M1/M2 paradigm, and the emerging theme of metabolic rewiring as a major mechanism for programming macrophage functions and pro-inflammatory activities. This sheds light into the many facets of macrophages in RA, their molecular regulation and their translational potential for developing novel protective and therapeutic strategies in the clinic.
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Affiliation(s)
- Eleni Siouti
- Laboratory of Immunobiology, Center for Clinical, Experimental Surgery and Translational Research, Biomedical Research Foundation of the Academy of Athens, 11527 Athens, Greece
| | - Evangelos Andreakos
- Laboratory of Immunobiology, Center for Clinical, Experimental Surgery and Translational Research, Biomedical Research Foundation of the Academy of Athens, 11527 Athens, Greece; Airway Disease Infection Section, National Heart and Lung Institute, Medical Research Council and Asthma UK Centre in Allergic Mechanisms of Asthma, Imperial College London, London W2 1NY, United Kingdom.
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