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Selective Calpain Inhibition Improves Functional and Histopathological Outcomes in a Canine Spinal Cord Injury Model. Int J Mol Sci 2022; 23:ijms231911772. [PMID: 36233068 PMCID: PMC9570220 DOI: 10.3390/ijms231911772] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 09/30/2022] [Accepted: 09/30/2022] [Indexed: 11/17/2022] Open
Abstract
Calpain activation has been implicated in various pathologies, including neurodegeneration. Thus, calpain inhibition could effectively prevent spinal cord injury (SCI) associated with neurodegeneration. In the current study, a dog SCI model was used to evaluate the therapeutic potential of a selective calpain inhibitor (PD150606) in combination with methylprednisolone sodium succinate (MPSS) as an anti-inflammatory drug. SCI was experimentally induced in sixteen mongrel dogs through an epidural balloon compression technique. The dogs were allocated randomly into four groups: control, MPSS, PD150606, and MPSS+PD150606. Clinical evaluation, serum biochemical, somatosensory evoked potentials, histopathological, and immunoblotting analyses were performed to assess treated dogs during the study. The current findings revealed that the combined administration of MPSS+PD150606 demonstrated considerably lower neuronal loss and microglial cell infiltration than the other groups, with a significant improvement in the locomotor score. The increased levels of inflammatory markers (GFAP and CD11) and calcium-binding proteins (Iba1 and S100) were significantly reduced in the combination group and to a lesser extent in MPSS or PD150606 treatment alone. Interestingly, the combined treatment effectively inhibited the calpain-induced cleavage of p35, limited cdk5 activation, and inhibited tau phosphorylation. These results suggest that early MPSS+PD150606 therapy after acute SCI may prevent subsequent neurodegeneration via calpain inhibition.
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Neuroimmune Mechanisms Underlying Neuropathic Pain: The Potential Role of TNF-α-Necroptosis Pathway. Int J Mol Sci 2022; 23:ijms23137191. [PMID: 35806192 PMCID: PMC9266916 DOI: 10.3390/ijms23137191] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 06/24/2022] [Accepted: 06/27/2022] [Indexed: 02/05/2023] Open
Abstract
The neuroimmune mechanism underlying neuropathic pain has been extensively studied. Tumor necrosis factor-alpha (TNF-α), a key pro-inflammatory cytokine that drives cytokine storm and stimulates a cascade of other cytokines in pain-related pathways, induces and modulates neuropathic pain by facilitating peripheral (primary afferents) and central (spinal cord) sensitization. Functionally, TNF-α controls the balance between cell survival and death by inducing an inflammatory response and two programmed cell death mechanisms (apoptosis and necroptosis). Necroptosis, a novel form of programmed cell death, is receiving increasing attraction and may trigger neuroinflammation to promote neuropathic pain. Chronic pain is often accompanied by adverse pain-associated emotional reactions and cognitive disorders. Overproduction of TNF-α in supraspinal structures such as the anterior cingulate cortex (ACC) and hippocampus plays an important role in pain-associated emotional disorders and memory deficits and also participates in the modulation of pain transduction. At present, studies reporting on the role of the TNF-α–necroptosis pathway in pain-related disorders are lacking. This review indicates the important research prospects of this pathway in pain modulation based on its role in anxiety, depression and memory deficits associated with other neurodegenerative diseases. In addition, we have summarized studies related to the underlying mechanisms of neuropathic pain mediated by TNF-α and discussed the role of the TNF-α–necroptosis pathway in detail, which may represent an avenue for future therapeutic intervention.
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Li QY, Chen SX, Liu JY, Yao PW, Duan YW, Li YY, Zang Y. Neuroinflammation in the anterior cingulate cortex: the potential supraspinal mechanism underlying the mirror-image pain following motor fiber injury. J Neuroinflammation 2022; 19:162. [PMID: 35725625 PMCID: PMC9210588 DOI: 10.1186/s12974-022-02525-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 06/06/2022] [Indexed: 11/10/2022] Open
Abstract
Background Peripheral nerve inflammation or lesion can affect contralateral healthy structures, and thus result in mirror-image pain. Supraspinal structures play important roles in the occurrence of mirror pain. The anterior cingulate cortex (ACC) is a first-order cortical region that responds to painful stimuli. In the present study, we systematically investigate and compare the neuroimmune changes in the bilateral ACC region using unilateral- (spared nerve injury, SNI) and mirror-(L5 ventral root transection, L5-VRT) pain models, aiming to explore the potential supraspinal neuroimmune mechanism underlying the mirror-image pain. Methods The up-and-down method with von Frey hairs was used to measure the mechanical allodynia. Viral injections for the designer receptors exclusively activated by designer drugs (DREADD) were used to modulate ACC glutamatergic neurons. Immunohistochemistry, immunofluorescence, western blotting, protein microarray were used to detect the regulation of inflammatory signaling. Results Increased expressions of tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6) and chemokine CX3CL1 in ACC induced by unilateral nerve injury were observed on the contralateral side in the SNI group but on the bilateral side in the L5-VRT group, representing a stronger immune response to L5-VRT surgery. In remote ACC, both SNI and L5-VRT induced robust bilateral increase in the protein level of Nav1.6 (SCN8A), a major voltage-gated sodium channel (VGSC) that regulates neuronal activity in the mammalian nervous system. However, the L5-VRT-induced Nav1.6 response occurred at PO 3d, earlier than the SNI-induced one, 7 days after surgery. Modulating ACC glutamatergic neurons via DREADD-Gq or DREADD-Gi greatly changed the ACC CX3CL1 levels and the mechanical paw withdrawal threshold. Neutralization of endogenous ACC CX3CL1 by contralateral anti-CX3CL1 antibody attenuated the induction and the maintenance of mechanical allodynia and eliminated the upregulation of CX3CL1, TNF-α and Nav1.6 protein levels in ACC induced by SNI. Furthermore, contralateral ACC anti-CX3CL1 also inhibited the expression of ipsilateral spinal c-Fos, Iba1, CD11b, TNF-α and IL-6. Conclusions The descending facilitation function mediated by CX3CL1 and its downstream cascade may play a pivotal role, leading to enhanced pain sensitization and even mirror-image pain. Strategies that target chemokine-mediated ACC hyperexcitability may lead to novel therapies for the treatment of neuropathic pain. Supplementary Information The online version contains supplementary material available at 10.1186/s12974-022-02525-8.
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Affiliation(s)
- Qiao-Yun Li
- Pain Research Center and Department of Physiology, Zhongshan Medical School of Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Brain Function and Disease, 74 Zhongshan Rd. 2, Guangzhou, 510080, People's Republic of China
| | - Shao-Xia Chen
- Department of Anesthesiology, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, 651 Dongfeng Road East, Guangzhou, 510060, People's Republic of China
| | - Jin-Yu Liu
- Pain Research Center and Department of Physiology, Zhongshan Medical School of Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Brain Function and Disease, 74 Zhongshan Rd. 2, Guangzhou, 510080, People's Republic of China
| | - Pei-Wen Yao
- Pain Research Center and Department of Physiology, Zhongshan Medical School of Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Brain Function and Disease, 74 Zhongshan Rd. 2, Guangzhou, 510080, People's Republic of China
| | - Yi-Wen Duan
- Pain Research Center and Department of Physiology, Zhongshan Medical School of Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Brain Function and Disease, 74 Zhongshan Rd. 2, Guangzhou, 510080, People's Republic of China
| | - Yong-Yong Li
- Pain Research Center and Department of Physiology, Zhongshan Medical School of Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Brain Function and Disease, 74 Zhongshan Rd. 2, Guangzhou, 510080, People's Republic of China
| | - Ying Zang
- Pain Research Center and Department of Physiology, Zhongshan Medical School of Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Brain Function and Disease, 74 Zhongshan Rd. 2, Guangzhou, 510080, People's Republic of China.
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Kowalski JL, Nguyen N, Battaglino RA, Falci SP, Charlifue S, Morse LR. miR-338-5p Levels and Cigarette Smoking are Associated With Neuropathic Pain Severity in Individuals With Spinal Cord Injury: Preliminary Findings From a Genome-Wide microRNA Expression Profiling Screen. Arch Phys Med Rehabil 2022; 103:738-746. [PMID: 34717922 DOI: 10.1016/j.apmr.2021.09.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 09/02/2021] [Accepted: 09/07/2021] [Indexed: 11/02/2022]
Abstract
OBJECTIVE To identify microRNA biomarkers and clinical factors associated with neuropathic pain after spinal cord injury. DESIGN Cross-sectional, secondary analysis of baseline data collected from ongoing clinical studies. Using a genome-wide microRNA screening approach, we studied differential microRNA expression in serum from 43 adults with spinal cord injury enrolled in ongoing clinical studies. Least squares regression was used to identify associations between microRNA expression, clinical factors, and neuropathic pain severity. SETTING Community-dwelling individuals with spinal cord injury. PARTICIPANTS Participants (N=43) were at least 18 years old with spinal cord injury, with 28 reporting neuropathic pain and 15 reporting no neuropathic pain. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Pain presence, type, and intensity were assessed with the International Spinal Cord Injury Pain Basic Data Set. Serum microRNA normalized deep sequencing counts were quantified from blood samples. Participant demographic factors, injury characteristics, medication use, and health habits were collected via questionnaire. RESULTS miR-338-5p expression and history of cigarette smoking were associated with and explained 37% of the variance in neuropathic pain severity (R2=0.37, F2,18=5.31, P=.02) independent of other clinical factors. No association was identified between miR-338-5p levels and nociceptive pain severity. CONCLUSIONS Our findings suggest that miR-338-5p and cigarette smoking may both play a role in the development or maintenance of neuropathic pain after spinal cord injury. While additional work is needed to confirm these findings, validated target analysis suggests a neuroprotective role of miR-338-5p in modulating neuroinflammation and neuronal apoptosis and that its downregulation may result in maladaptive neuroplastic mechanisms contributing to neuropathic pain after spinal cord injury.
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Affiliation(s)
- Jesse L Kowalski
- Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, Minnesota
| | - Nguyen Nguyen
- Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, Minnesota
| | - Ricardo A Battaglino
- Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, Minnesota
| | - Scott P Falci
- Department of Neurosurgery, Swedish Medical Center, Englewood, Colorado; Research Department, Craig Hospital, Englewood, Colorado
| | | | - Leslie R Morse
- Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, Minnesota.
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Nicotinamide adenine dinucleotide phosphate oxidase 2-derived reactive oxygen species contribute to long-term potentiation of C-fiber-evoked field potentials in spinal dorsal horn and persistent mirror-image pain following high-frequency stimulus of the sciatic nerve. Pain 2021; 161:758-772. [PMID: 32195784 DOI: 10.1097/j.pain.0000000000001761] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
High-frequency stimulation (HFS) of the sciatic nerve has been reported to produce long-term potentiation (LTP) and long-lasting pain hypersensitivity in rats. However, the central underlying mechanism remains unclear. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) belongs to a group of electron-transporting transmembrane enzymes that produce reactive oxygen species (ROS). Here, we found that NOX2 was upregulated in the lumbar spinal dorsal horn after HFS of the left sciatic nerve, which induced bilateral pain and spinal LTP in both male and female rats. Blocking NOX2 with blocking peptide or shRNA prevented the development of bilateral mechanical allodynia, the induction of spinal LTP, and the phosphorylation of N-methyl-d-aspartate (NMDA) receptor 2B (GluN2B) and nuclear factor kappa-B (NF-κB) p65 after HFS. Moreover, NOX2 shRNA reduced the frequency and amplitude of both spontaneous excitatory postsynaptic currents and miniature excitatory postsynaptic currents in laminar II neurons. Furthermore, 8-hydroxyguanine (8-OHG), an oxidative stress marker, was increased in the spinal dorsal horn. Spinal application of ROS scavenger, Phenyl-N-tert-butylnitrone (PBN), depressed the already established spinal LTP. Spinal application of H2O2, one ROS, induced LTP and bilateral mechanical allodynia, increased the frequency and amplitude of spontaneous excitatory postsynaptic currents in laminar II neurons, and phosphorylated GluN2B and p65 in the dorsal horn. This study provided electrophysiological and behavioral evidence that NOX2-derived ROS in the spinal cord contributed to persistent mirror-image pain by enhancing the synaptic transmission, which was mediated by increasing presynaptic glutamate release and activation of NMDA receptor and NF-κB in the spinal dorsal horn.
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Yao Y, Fu KY. Serum-deprivation leads to activation-like changes in primary microglia and BV-2 cells but not astrocytes. Biomed Rep 2020; 13:51. [PMID: 32974017 DOI: 10.3892/br.2020.1358] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 07/28/2020] [Indexed: 12/22/2022] Open
Abstract
The aim of the present study was to determine the effect of serum deprivation on primary microglia, BV-2 cells and primary astrocytes. Cell morphology combined with the expression of phospho-(p-)38 and p-extracellular signal-regulated kinase (ERK) were assessed. Serum deprivation resulted in various alterations in the three cell cultures. Primary microglia and BV-2 cells exhibited alterations indicative of activation under serum treatment, as well as lipopolysaccharide (LPS) treatment. However, astrocytes did not react as fast. Regarding morphology, the processes present on the primary microglia and BV-2 cells became shorter and the cell bodies became larger, and more transparent vesicles were observed within the cell bodies, which indicated their increased phagocytic ability. At the protein level, p-p38 expression increased quickly within 1 h in the primary microglia culture in response to LPS treatment. Furthermore, the expression levels of p-p38 and p-ERK were elevated in both primary microglia and BV-2 cells under serum deprivation, as well as under LPS treatment, which was not observed in the primary astrocytes. These results suggest that serum deprivation may result in similar changes to cell morphology and the expression levels of p-p38 and p-ERK as LPS treatment in primary microglia and BV-2 cells. These observations suggest that primary microglia and BV-2 cells may become activated under serum deprivation, at least to a certain degree.
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Affiliation(s)
- Yao Yao
- Department of Oral and Maxillofacial Surgery, Beijing Stomatological Hospital and School of Stomatology, Capital Medical University, Beijing 100050, P.R. China
| | - Kai-Yuan Fu
- Center for TMD and Orofacial Pain, Peking University School and Hospital of Stomatology, Beijing 100081, P.R. China
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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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Yuan Q, Liu X, Xian YF, Yao M, Zhang X, Huang P, Wu W, Lin ZX. Satellite glia activation in dorsal root ganglion contributes to mechanical allodynia after selective motor fiber injury in adult rats. Biomed Pharmacother 2020; 127:110187. [PMID: 32361638 DOI: 10.1016/j.biopha.2020.110187] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 04/16/2020] [Accepted: 04/17/2020] [Indexed: 12/26/2022] Open
Abstract
Increasing evidence suggests that activation of satellite glia cells (SGCs) in sensory ganglia play important roles in the development of neuropathic pain. The present study aimed to investigate the involvement of SGC activation in a novel model of motor nerve injury induced pain hypersensitivity. The neuropathic pain model was established by cervical 8 ventral root avulsion (C8VA). Glial fibrillary acidic protein (GFAP) was used as a marker of SGC activation. Unilateral C8VA resulted in mechanical allodynia, but not thermal hyperalgesia in bilateral paws. Expectedly, SGCs were robustly activated on as early as 1 day and persisted for at least 7 days in the ipsilateral and contralateral dorsal root ganglia (DRG) of C6, C7 and C8 after C8VA. Double immunofluorescence showed that almost all the activated SGCs enveloped neurofilament 200 (NF200) positive myelinated neurons in DRG. Local application of fluorocitrate (FC), a glial metabolism inhibitor, significantly decreased the number of activated SGCs and alleviated bilateral mechanical allodynia. These results suggest that SGC activation contributed to ipsilateral and mirror-image pain hypersensitivity after C8VA. Inhibition of SGC activation represented a promising therapeutic strategy for the management of neuropathic pain following brachial plexus root avulsion.
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Affiliation(s)
- Qiuju Yuan
- School of Chinese Medicine, Faculty of Medicine, The Chinese University of Hong Kong, China; Brain Research Centre, Faculty of Medicine, The Chinese University of Hong Kong, China.
| | - Xiaodong Liu
- Department of Anaesthesia and Intensive Care, Faculty of Medicine, The Chinese University of Hong Kong, China
| | - Yan-Fang Xian
- School of Chinese Medicine, Faculty of Medicine, The Chinese University of Hong Kong, China; Brain Research Centre, Faculty of Medicine, The Chinese University of Hong Kong, China
| | - Min Yao
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, China
| | - Xie Zhang
- School of Chinese Medicine, Faculty of Medicine, The Chinese University of Hong Kong, China
| | - Pengyun Huang
- School of Chinese Medicine, Faculty of Medicine, The Chinese University of Hong Kong, China
| | - Wutian Wu
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, China; GHM Institute of CNS Regeneration, Jinan University, Guangzhou, China
| | - Zhi-Xiu Lin
- School of Chinese Medicine, Faculty of Medicine, The Chinese University of Hong Kong, China; Brain Research Centre, Faculty of Medicine, The Chinese University of Hong Kong, China.
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9
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Suppression of Superficial Microglial Activation by Spinal Cord Stimulation Attenuates Neuropathic Pain Following Sciatic Nerve Injury in Rats. Int J Mol Sci 2020; 21:ijms21072390. [PMID: 32235682 PMCID: PMC7177766 DOI: 10.3390/ijms21072390] [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] [Received: 02/27/2020] [Revised: 03/27/2020] [Accepted: 03/27/2020] [Indexed: 12/29/2022] Open
Abstract
We evaluated the mechanisms underlying the spinal cord stimulation (SCS)-induced analgesic effect on neuropathic pain following spared nerve injury (SNI). On day 3 after SNI, SCS was performed for 6 h by using electrodes paraspinally placed on the L4-S1 spinal cord. The effects of SCS and intraperitoneal minocycline administration on plantar mechanical sensitivity, microglial activation, and neuronal excitability in the L4 dorsal horn were assessed on day 3 after SNI. The somatosensory cortical responses to electrical stimulation of the hind paw on day 3 following SNI were examined by using in vivo optical imaging with a voltage-sensitive dye. On day 3 after SNI, plantar mechanical hypersensitivity and enhanced microglial activation were suppressed by minocycline or SCS, and L4 dorsal horn nociceptive neuronal hyperexcitability was suppressed by SCS. In vivo optical imaging also revealed that electrical stimulation of the hind paw-activated areas in the somatosensory cortex was decreased by SCS. The present findings suggest that SCS could suppress plantar SNI-induced neuropathic pain via inhibition of microglial activation in the L4 dorsal horn, which is involved in spinal neuronal hyperexcitability. SCS is likely to be a potential alternative and complementary medicine therapy to alleviate neuropathic pain following nerve injury.
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Liang YJ, Feng SY, Qi YP, Li K, Jin ZR, Jing HB, Liu LY, Cai J, Xing GG, Fu KY. Contribution of microglial reaction to increased nociceptive responses in high-fat-diet (HFD)-induced obesity in male mice. Brain Behav Immun 2019; 80:777-792. [PMID: 31108168 DOI: 10.1016/j.bbi.2019.05.026] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Revised: 05/11/2019] [Accepted: 05/16/2019] [Indexed: 12/27/2022] Open
Abstract
The progressive increase in the prevalence of obesity in the population can result in increased healthcare costs and demands. Recent studies have revealed a positive correlation between pain and obesity, although the underlying mechanisms still remain unknown. Here, we aimed to clarify the role of microglia in altered pain behaviors induced by high-fat diet (HFD) in male mice. We found that C57BL/6CR mice on HFD exhibited enhanced spinal microglial reaction (increased cell number and up-regulated expression of p-p38 and CD16/32), increased tumor necrosis factor-α (TNF-α) mRNA and brain-derived neurotrophic factor (BDNF) protein expression as well as a polarization of spinal microglial toward a pro-inflammatory phenotype. Moreover, we found that using PLX3397 (a selective colony-stimulating factor-1 receptor (CSF1R) kinase inhibitor) to eliminate microglia in HFD-induced obesity mice, inflammation in the spinal cord was rescued, as was abnormal pain hypersensitivity. Intrathecal injection of Mac-1-saporin (a saporin-conjugated anti-mac1 antibody) resulted in a decreased number of microglia and attenuated both mechanical allodynia and thermal hyperalgesia in HFD-fed mice. These results indicate that the pro-inflammatory functions of spinal microglia have a special relevance to abnormal pain hypersensitivity in HFD-induced obesity mice. In conclusion, our data suggest that HFD induces a classical reaction of microglia, characterized by an enhanced phosphorylation of p-38 and increased CD16/32 expression, which may in part contribute to increased nociceptive responses in HFD-induced obesity mice.
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Affiliation(s)
- Ya-Jing Liang
- Center for TMD and Orofacial Pain, Peking University School and Hospital of Stomatology, Beijing 100081, China
| | - Shi-Yang Feng
- Center for TMD and Orofacial Pain, Peking University School and Hospital of Stomatology, Beijing 100081, China
| | - Ya-Ping Qi
- Center for TMD and Orofacial Pain, Peking University School and Hospital of Stomatology, Beijing 100081, China
| | - Kai Li
- Center for TMD and Orofacial Pain, Peking University School and Hospital of Stomatology, Beijing 100081, China
| | - Zi-Run Jin
- Department of Neurobiology, School of Basic Medical Sciences and Neuroscience Research Institute, Peking University, Beijing 100083, China
| | - Hong-Bo Jing
- Department of Neurobiology, School of Basic Medical Sciences and Neuroscience Research Institute, Peking University, Beijing 100083, China
| | - Ling-Yu Liu
- Department of Neurobiology, School of Basic Medical Sciences and Neuroscience Research Institute, Peking University, Beijing 100083, China
| | - Jie Cai
- Department of Neurobiology, School of Basic Medical Sciences and Neuroscience Research Institute, Peking University, Beijing 100083, China
| | - Guo-Gang Xing
- Department of Neurobiology, School of Basic Medical Sciences and Neuroscience Research Institute, Peking University, Beijing 100083, China; Key Laboratory for Neuroscience, Ministry of Education/National Health Commission, Peking University, Beijing 100083, China.
| | - Kai-Yuan Fu
- Center for TMD and Orofacial Pain, Peking University School and Hospital of Stomatology, Beijing 100081, China; Key Laboratory for Neuroscience, Ministry of Education/National Health Commission, Peking University, Beijing 100083, China.
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Yao PW, Wang SK, Chen SX, Xin WJ, Liu XG, Zang Y. Upregulation of tumor necrosis factor-alpha in the anterior cingulate cortex contributes to neuropathic pain and pain-associated aversion. Neurobiol Dis 2019; 130:104456. [PMID: 31028871 DOI: 10.1016/j.nbd.2019.04.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 04/10/2019] [Accepted: 04/23/2019] [Indexed: 10/26/2022] Open
Abstract
Injury associated pain involves subjective perception and emotional experience. The anterior cingulate cortex (ACC) is a key area involved in the affective component of pain processing. However, the neuroimmune mechanisms underlying enhanced ACC excitability following peripheral nerve injury are still not fully understood. Our previous work has shown that tumor necrosis factor-alpha (TNF-α) overexpression leads to peripheral afferent hyperexcitability and synaptic transmission potentiation in spinal cord. Here, we aimed to reveal the potential role of ACC TNF-α in ACC hyperexcitability and neuropathic pain. c-Fos, a widely used neuronal activity marker, was induced especially in contralateral ACC early [postoperative (PO) 1 h] and later (PO day 7 and 10) during the development of neuropathic pain. Spared nerve injury (SNI) elevated TNF-α level in contralateral ACC from PO day 5 to 14, delayed relative to decreased ipsilateral paw withdrawal threshold apparent from PO day 1 to 14. Microinjection of anti-TNF-α antibody into the ACC completely eliminated c-Fos overexpression and greatly attenuated pain aversion and mechanical allodynia induced by SNI, suggesting an important role of ACC TNF-α in the pain aversiveness and pain maintenance. Furthermore, modulating ACC pyramidal neurons via a Gi-coupled human M4 muscarinic receptor (hM4Di) or a Gq-coupled human M3 muscarinic receptor (hM3Dq), a type of designer receptors exclusively activated by designer drugs (DREADD), greatly changed the ACC TNF-α level and the mechanical paw withdrawal threshold. The positive interactions between TNF-α and ACC neurons might modulate the cytokine microenvironment thus contribute to the neuropathic pain.
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Affiliation(s)
- Pei-Wen Yao
- Pain Research Center and Department of Physiology, Zhongshan Medical School, Sun Yat-Sen University, 74 Zhongshan Rd. 2, Guangzhou 510080, PR China
| | - Shao-Kun Wang
- Pain Research Center and Department of Physiology, Zhongshan Medical School, Sun Yat-Sen University, 74 Zhongshan Rd. 2, Guangzhou 510080, PR China
| | - Shao-Xia Chen
- Pain Research Center and Department of Physiology, Zhongshan Medical School, Sun Yat-Sen University, 74 Zhongshan Rd. 2, Guangzhou 510080, PR China; Department of Anesthesiology, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, 651 Dongfeng Road East, Guangzhou 510060, PR China
| | - Wen-Jun Xin
- Pain Research Center and Department of Physiology, Zhongshan Medical School, Sun Yat-Sen University, 74 Zhongshan Rd. 2, Guangzhou 510080, PR China
| | - Xian-Guo Liu
- Pain Research Center and Department of Physiology, Zhongshan Medical School, Sun Yat-Sen University, 74 Zhongshan Rd. 2, Guangzhou 510080, PR China
| | - Ying Zang
- Pain Research Center and Department of Physiology, Zhongshan Medical School, Sun Yat-Sen University, 74 Zhongshan Rd. 2, Guangzhou 510080, PR China.
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Ji L, Chen Y, Wei H, Feng H, Chang R, Yu D, Wang X, Gong X, Zhang M. Activation of alpha7 acetylcholine receptors reduces neuropathic pain by decreasing dynorphin A release from microglia. Brain Res 2019; 1715:57-65. [PMID: 30898676 DOI: 10.1016/j.brainres.2019.03.016] [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: 08/04/2018] [Revised: 01/09/2019] [Accepted: 03/16/2019] [Indexed: 12/17/2022]
Abstract
Dynorphin A is increased in neuropathic pain models. Activation of α7 n acetylcholine receptor (nAchR) reduces inflammation and pain. Whether activation of α7 nAchR affects dynorphin A release is unknown. The experiments evaluated the proinflammatory effect of dynorphin A in the spinal nerve ligation-induced neuropathic pain models and the effect of α7 nAchR activation on the dynorphin A content. α7 nAchR agonist, PHA-543613 and its antagonist, methyllycaconitine citrate were used and dynorphin A content was measured after spinal nerve ligation and in microglia cultures to test the analgesic mechanisms of α7 nAchR activation. The results showed that dynorphin A content peaked 3 to 7 days after nerve injury, and dynorphin A anti-serum intrathecal injection decreased IL-β and TNF-α content a week after nerve injury. Activation of α7 nAchR by PHA-543613 alleviated neuropathic pain behaviors and decreased dynorphin A concentration in the ipsilateral spinal cords. Also, PHA-543613 decreased dynorphin A release from the microglia cultures to LPS stimulation by activation of α7 nAchR. Our results suggest that dynorphin A contribute to the development and maintenance of neuropathic pain and that decreasing dynorphin A content by activation of α7 AchR of microglia is a potential therapeutic target for treating neuropathic pain.
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Affiliation(s)
- Liu Ji
- Department of Anesthesiology, Shiyan Taihe Hospital, Affiliated Hospital of Hubei University of Medicine, Hubei, Shiyan, China; Institute of Anesthesiology, Department of Anesthesiology, Hubei University of Medicine, Hubei, Shiyan, China
| | - Yongmei Chen
- Department of Laboratory, Shiyan Taihe Hospital, Affiliated Hospital of Hubei University of Medicine, Hubei, Shiyan, China
| | - Huixia Wei
- Department of Anesthesiology, Shiyan Taihe Hospital, Affiliated Hospital of Hubei University of Medicine, Hubei, Shiyan, China; Institute of Anesthesiology, Department of Anesthesiology, Hubei University of Medicine, Hubei, Shiyan, China
| | - Hui Feng
- Department of Anesthesiology, Shiyan Taihe Hospital, Affiliated Hospital of Hubei University of Medicine, Hubei, Shiyan, China; Institute of Anesthesiology, Department of Anesthesiology, Hubei University of Medicine, Hubei, Shiyan, China
| | - Ruijie Chang
- Department of Anesthesiology, Shiyan Taihe Hospital, Affiliated Hospital of Hubei University of Medicine, Hubei, Shiyan, China; Institute of Anesthesiology, Department of Anesthesiology, Hubei University of Medicine, Hubei, Shiyan, China
| | - Di Yu
- Department of Anesthesiology, Shiyan Taihe Hospital, Affiliated Hospital of Hubei University of Medicine, Hubei, Shiyan, China; Institute of Anesthesiology, Department of Anesthesiology, Hubei University of Medicine, Hubei, Shiyan, China
| | - Xianyu Wang
- Department of Anesthesiology, Shiyan Taihe Hospital, Affiliated Hospital of Hubei University of Medicine, Hubei, Shiyan, China; Institute of Anesthesiology, Department of Anesthesiology, Hubei University of Medicine, Hubei, Shiyan, China.
| | - Xingrui Gong
- Department of Anesthesiology, Shiyan Taihe Hospital, Affiliated Hospital of Hubei University of Medicine, Hubei, Shiyan, China; Institute of Anesthesiology, Department of Anesthesiology, Hubei University of Medicine, Hubei, Shiyan, China; Department of Anesthesiology and Pediatric Clinical Pharmacology Laboratory, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Mazhong Zhang
- Department of Anesthesiology and Pediatric Clinical Pharmacology Laboratory, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
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Guo WL, Qu WR, Zeng LN, Qi ZP, Huang C, Zhu Z, Li R. l-Theanine and NEP1-40 promote nerve regeneration and functional recovery after brachial plexus root avulsion. Biochem Biophys Res Commun 2019; 508:1126-1132. [DOI: 10.1016/j.bbrc.2018.11.124] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2018] [Accepted: 11/20/2018] [Indexed: 01/19/2023]
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14
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Yang T, Du S, Liu X, Ye X, Wei X. Withdrawal from spinal application of remifentanil induces long-term potentiation of c-fiber-evoked field potentials by activation of Src family kinases in spinal microglia. Neurochem Res 2018; 43:1660-1670. [PMID: 29959648 DOI: 10.1007/s11064-018-2582-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 06/08/2018] [Accepted: 06/20/2018] [Indexed: 12/12/2022]
Abstract
It is well known that remifentanil, a widely used intravenous anesthesia drug, can paradoxically induce hyperalgesia. The underlying mechanisms are still not clear despite the wide investigations. The present study demonstrated that withdrawal from spinal application of remifentanil could dose-dependently induce long term potentiation (LTP) of C-fiber evoked field potentials. Remifentanil withdrawal could activate Src family kinases (SFKs) in microglia, and upregulate the expression of tumor necrosis factor alpha (TNFα) in spinal dorsal horn. Furthermore, pretreatment with either microglia inhibitor Minocycline, SFKs inhibitor PP2 or TNF αneutralization antibody could block remifentanil withdrawal induced spinal LTP, whereas supplement of recombinant rat TNFα to the spinal cord could reverse the inhibitory effect of Minocycline or PP2 on remifentanil withdrawal induced LTP. Our results suggested that TNFαrelease following SFKs activation in microglia is involved in the induction of LTP induced by remifentanil withdrawal.
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Affiliation(s)
- Tao Yang
- Department of Anesthesiology, SunYat-SenMemorial Hospital, SunYat-Sen University, 107 Yanjiang Xi Road, Guangzhou, People's Republic of China
| | - Sujuan Du
- Department of Anesthesiology, SunYat-SenMemorial Hospital, SunYat-Sen University, 107 Yanjiang Xi Road, Guangzhou, People's Republic of China
| | - Xianguo Liu
- Department of Physiology and Pain Research Center, Zhongshan School of Medicine, Sun Yat-sen University, 74 Zhongshan Road 2, Guangzhou, 510080, People's Republic of China.,Guangdong Provincial Key Laboratory of Brain Function and Disease, Guangzhou, Guangdong, People's Republic of China
| | - Xijiu Ye
- Department of Anesthesiology, SunYat-SenMemorial Hospital, SunYat-Sen University, 107 Yanjiang Xi Road, Guangzhou, People's Republic of China.
| | - Xuhong Wei
- Department of Physiology and Pain Research Center, Zhongshan School of Medicine, Sun Yat-sen University, 74 Zhongshan Road 2, Guangzhou, 510080, People's Republic of China. .,Guangdong Provincial Key Laboratory of Brain Function and Disease, Guangzhou, Guangdong, People's Republic of China.
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