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Singh NK, Gandu SR, Li L, Ni L, Acioglu C, Mirabelli E, Hiester LL, Elkabes S, Firestein BL. Cypin Inhibition as a Therapeutic Approach to Treat Spinal Cord Injury-Induced Mechanical Pain. eNeuro 2024; 11:ENEURO.0451-23.2024. [PMID: 38302457 PMCID: PMC10875717 DOI: 10.1523/eneuro.0451-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 12/24/2023] [Accepted: 01/04/2024] [Indexed: 02/03/2024] Open
Abstract
Cypin (cytosolic postsynaptic density protein 95 interactor) is the primary guanine deaminase in the central nervous system (CNS), promoting the metabolism of guanine to xanthine, an important reaction in the purine salvage pathway. Activation of the purine salvage pathway leads to the production of uric acid (UA). UA has paradoxical effects, specifically in the context of CNS injury as it confers neuroprotection, but it also promotes pain. Since neuropathic pain is a comorbidity associated with spinal cord injury (SCI), we postulated that small molecule cypin inhibitor B9 treatment could attenuate SCI-induced neuropathic pain, potentially by interfering with UA production. However, we also considered that this treatment could hinder the neuroprotective effects of UA and, in doing so, exacerbate SCI outcomes. To address our hypothesis, we induced a moderate midthoracic contusion SCI in female mice and assessed whether transient intrathecal administration of B9, starting at 1 d postinjury (dpi) until 7 dpi, attenuates mechanical pain in hindlimbs at 3 weeks pi. We also evaluated the effects of B9 on the spontaneous recovery of locomotor function. We found that B9 alleviates mechanical pain but does not affect locomotor function. Importantly, B9 does not exacerbate lesion volume at the epicenter. In accordance with these findings, B9 does not aggravate glutamate-induced excitotoxic death of SC neurons in vitro. Moreover, SCI-induced increased astrocyte reactivity at the glial scar is not altered by B9 treatment. Our data suggest that B9 treatment reduces mechanical pain without exerting major detrimental effects following SCI.
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Affiliation(s)
- Nisha K Singh
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854
- Molecular Biosciences Graduate Program, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854
| | - Srinivasa R Gandu
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854
- Molecular Biosciences Graduate Program, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854
| | - Lun Li
- Department of Neurosurgery, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey 07101
| | - Li Ni
- Department of Neurosurgery, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey 07101
| | - Cigdem Acioglu
- Department of Neurosurgery, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey 07101
| | - Ersilia Mirabelli
- Department of Neurosurgery, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey 07101
| | - Liam L Hiester
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854
| | - Stella Elkabes
- Department of Neurosurgery, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey 07101
| | - Bonnie L Firestein
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854
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Garifulin R, Davleeva M, Izmailov A, Fadeev F, Markosyan V, Shevchenko R, Minyazeva I, Minekayev T, Lavrov I, Islamov R. Evaluation of the Autologous Genetically Enriched Leucoconcentrate on the Lumbar Spinal Cord Morpho-Functional Recovery in a Mini Pig with Thoracic Spine Contusion Injury. Biomedicines 2023; 11:biomedicines11051331. [PMID: 37239001 DOI: 10.3390/biomedicines11051331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 04/27/2023] [Accepted: 04/27/2023] [Indexed: 05/28/2023] Open
Abstract
BACKGROUND Pathological changes associated with spinal cord injury (SCI) can be observed distant, rostral, or caudal to the epicenter of injury. These remote areas represent important therapeutic targets for post-traumatic spinal cord repair. The present study aimed to investigate the following in relation to SCI: distant changes in the spinal cord, peripheral nerve, and muscles. METHODS The changes in the spinal cord, the tibial nerve, and the hind limb muscles were evaluated in control SCI animals and after intravenous infusion of autologous leucoconcentrate enriched with genes encoding neuroprotective factors (VEGF, GDNF, and NCAM), which previously demonstrated a positive effect on post-traumatic restoration. RESULTS Two months after thoracic contusion in the treated mini pigs, a positive remodeling of the macro- and microglial cells, expression of PSD95 and Chat in the lumbar spinal cord, and preservation of the number and morphological characteristics of the myelinated fibers in the tibial nerve were observed and were aligned with hind limb motor recovery and reduced soleus muscle atrophy. CONCLUSION Here, we show the positive effect of autologous genetically enriched leucoconcentrate-producing recombinant neuroprotective factors on targets distant to the primary lesion site in mini pigs with SCI. These findings open new perspectives for the therapy of SCI.
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Affiliation(s)
- Ravil Garifulin
- Department of Histology, Cytology and Embryology, Kazan State Medical University, 420012 Kazan, Russia
| | - Maria Davleeva
- Department of Histology, Cytology and Embryology, Kazan State Medical University, 420012 Kazan, Russia
| | - Andrei Izmailov
- Department of Histology, Cytology and Embryology, Kazan State Medical University, 420012 Kazan, Russia
| | - Filip Fadeev
- Department of Histology, Cytology and Embryology, Kazan State Medical University, 420012 Kazan, Russia
| | - Vage Markosyan
- Department of Histology, Cytology and Embryology, Kazan State Medical University, 420012 Kazan, Russia
| | - Roman Shevchenko
- Department of Histology, Cytology and Embryology, Kazan State Medical University, 420012 Kazan, Russia
| | - Irina Minyazeva
- Department of Histology, Cytology and Embryology, Kazan State Medical University, 420012 Kazan, Russia
| | - Tagir Minekayev
- Department of Histology, Cytology and Embryology, Kazan State Medical University, 420012 Kazan, Russia
| | - Igor Lavrov
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA
| | - Rustem Islamov
- Department of Histology, Cytology and Embryology, Kazan State Medical University, 420012 Kazan, Russia
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Chen Y, Chen H, Li XC, Mi WL, Chu YX, Wang YQ, Mao-Ying QL. Neuronal toll like receptor 9 contributes to complete Freund’s adjuvant-induced inflammatory pain in mice. Front Mol Neurosci 2022; 15:1008203. [PMID: 36277489 PMCID: PMC9582929 DOI: 10.3389/fnmol.2022.1008203] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Accepted: 09/12/2022] [Indexed: 11/13/2022] Open
Abstract
Toll like receptor 9 (TLR9) is a critical sensor for danger-associated molecular patterns (DAMPs) and a crucial marker of non-sterile/sterile inflammation among all TLRs. However, the significance of TLR9 in inflammatory pain remains unclear. Here, we subcutaneously injected Complete Freund’s adjuvant (CFA) into the plantar surface of the hind paw, to established a mouse model of inflammatory pain, and we examined expression and distribution of TLR9 in this model. There was a significant increase of TLR9 mRNA and reduction of mechanical paw withdrawal threshold in mice intraplantar injected with CFA. By contrast, mechanical paw withdrawal threshold significantly increased in mice treated with TLR9 antagonist ODN2088. Furthermore, TLR9 is found predominantly distributed in the neurons by immunofluorescence experiment. Accordingly, neuronal TLR9 downregulation in the spinal cord prevented CFA-induced persistent hyperalgesia. Overall, these findings indicate that neuronal TLR9 in the spinal cord is closely related to CFA-induced inflammatory pain. It provides a potential treatment option for CFA-induced inflammatory pain by applying TLR9 antagonist.
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Affiliation(s)
- Yu Chen
- Department of Integrative Medicine and Neurobiology, School of Basic Medical Sciences, Shanghai Medical College, Institute of Acupuncture Research, Institutes of Integrative Medicine, Fudan University, Shanghai, China
| | - Hui Chen
- Department of Integrative Medicine and Neurobiology, School of Basic Medical Sciences, Shanghai Medical College, Institute of Acupuncture Research, Institutes of Integrative Medicine, Fudan University, Shanghai, China
| | - Xiao-Chen Li
- Department of Integrative Medicine and Neurobiology, School of Basic Medical Sciences, Shanghai Medical College, Institute of Acupuncture Research, Institutes of Integrative Medicine, Fudan University, Shanghai, China
| | - Wen-Li Mi
- Department of Integrative Medicine and Neurobiology, School of Basic Medical Sciences, Shanghai Medical College, Institute of Acupuncture Research, Institutes of Integrative Medicine, Fudan University, Shanghai, China
- Shanghai Key Laboratory of Acupuncture Mechanism and Acupoint Function, Fudan University, Shanghai, China
| | - Yu-Xia Chu
- Department of Integrative Medicine and Neurobiology, School of Basic Medical Sciences, Shanghai Medical College, Institute of Acupuncture Research, Institutes of Integrative Medicine, Fudan University, Shanghai, China
- Shanghai Key Laboratory of Acupuncture Mechanism and Acupoint Function, Fudan University, Shanghai, China
| | - Yan-Qing Wang
- Department of Integrative Medicine and Neurobiology, School of Basic Medical Sciences, Shanghai Medical College, Institute of Acupuncture Research, Institutes of Integrative Medicine, Fudan University, Shanghai, China
- Shanghai Key Laboratory of Acupuncture Mechanism and Acupoint Function, Fudan University, Shanghai, China
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Qi-Liang Mao-Ying
- Department of Integrative Medicine and Neurobiology, School of Basic Medical Sciences, Shanghai Medical College, Institute of Acupuncture Research, Institutes of Integrative Medicine, Fudan University, Shanghai, China
- Shanghai Key Laboratory of Acupuncture Mechanism and Acupoint Function, Fudan University, Shanghai, China
- *Correspondence: Qi-Liang Mao-Ying,
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Zhang Y, Al Mamun A, Yuan Y, Lu Q, Xiong J, Yang S, Wu C, Wu Y, Wang J. Acute spinal cord injury: Pathophysiology and pharmacological intervention (Review). Mol Med Rep 2021; 23:417. [PMID: 33846780 PMCID: PMC8025476 DOI: 10.3892/mmr.2021.12056] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Accepted: 11/12/2020] [Indexed: 12/12/2022] Open
Abstract
Spinal cord injury (SCI) is one of the most debilitating of all the traumatic conditions that afflict individuals. For a number of years, extensive studies have been conducted to clarify the molecular mechanisms of SCI. Experimental and clinical studies have indicated that two phases, primary damage and secondary damage, are involved in SCI. The initial mechanical damage is caused by local impairment of the spinal cord. In addition, the fundamental mechanisms are associated with hyperflexion, hyperextension, axial loading and rotation. By contrast, secondary injury mechanisms are led by systemic and cellular factors, which may also be initiated by the primary injury. Although significant advances in supportive care have improved clinical outcomes in recent years, a number of studies continue to explore specific pharmacological therapies to minimize SCI. The present review summarized some important pathophysiologic mechanisms that are involved in SCI and focused on several pharmacological and non‑pharmacological therapies, which have either been previously investigated or have a potential in the management of this debilitating injury in the near future.
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Affiliation(s)
- Yi Zhang
- School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu 210094, P.R. China
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, P.R. China
| | - Abdullah Al Mamun
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, P.R. China
| | - Yuan Yuan
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, P.R. China
| | - Qi Lu
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, P.R. China
| | - Jun Xiong
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, P.R. China
| | - Shulin Yang
- School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu 210094, P.R. China
| | - Chengbiao Wu
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, P.R. China
| | - Yanqing Wu
- Institute of Life Sciences, Wenzhou University, Wenzhou, Zhejiang 325035, P.R. China
| | - Jian Wang
- Department of Hand Surgery and Peripheral Neurosurgery, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325035, P.R. China
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Fakhri S, Abbaszadeh F, Jorjani M. On the therapeutic targets and pharmacological treatments for pain relief following spinal cord injury: A mechanistic review. Biomed Pharmacother 2021; 139:111563. [PMID: 33873146 DOI: 10.1016/j.biopha.2021.111563] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Revised: 03/29/2021] [Accepted: 03/31/2021] [Indexed: 12/11/2022] Open
Abstract
Spinal cord injury (SCI) is globally considered as one of the most debilitating disorders, which interferes with daily activities and life of the affected patients. Despite many developments in related recognizing and treating procedures, post-SCI neuropathic pain (NP) is still a clinical challenge for clinicians with no distinct treatments. Accordingly, a comprehensive search was conducted in PubMed, Medline, Scopus, Web of Science, and national database (SID and Irandoc). The relevant articles regarding signaling pathways, therapeutic targets and pharmacotherapy of post-SCI pain were also reviewed. Data were collected with no time limitation until November 2020. The present study provides the findings on molecular mechanisms and therapeutic targets, as well as developing the critical signaling pathways to introduce novel neuroprotective treatments of post-SCI pain. From the pathophysiological mechanistic point of view, post-SCI inflammation activates the innate immune system, in which the immune cells elicit secondary injuries. So, targeting the critical signaling pathways for pain management in the SCI population has significant importance in providing new treatments. Indeed, several receptors, ion channels, excitatory neurotransmitters, enzymes, and key signaling pathways could be used as therapeutic targets, with a pivotal role of n-methyl-D-aspartate, gamma-aminobutyric acid, and inflammatory mediators. The current review focuses on conventional therapies, as well as crucial signaling pathways and promising therapeutic targets for post-SCI pain to provide new insights into the clinical treatment of post-SCI pain. The need to develop innovative delivery systems to treat SCI is also considered.
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Affiliation(s)
- Sajad Fakhri
- Pharmaceutical Sciences Research Center, Health Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Fatemeh Abbaszadeh
- Neurobiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Department of Neuroscience, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran
| | - Masoumeh Jorjani
- Neurobiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Department of Pharmacology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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Zhao C, Xing Z, Zhang C, Fan Y, Liu H. Nanopharmaceutical-based regenerative medicine: a promising therapeutic strategy for spinal cord injury. J Mater Chem B 2021; 9:2367-2383. [PMID: 33662083 DOI: 10.1039/d0tb02740e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Spinal cord injury (SCI) is a neurological disorder that can lead to loss of perceptive and athletic function due to the severe nerve damage. To date, pieces of evidence detailing the precise pathological mechanisms in SCI are still unclear. Therefore, drug therapy cannot effectively alleviate the SCI symptoms and faces the limitations of systemic administration with large side effects. Thus, the development of SCI treatment strategies is urgent and valuable. Due to the application of nanotechnology in pharmaceutical research, nanopharmaceutical-based regenerative medicine will bring colossal development space for clinical medicine. These nanopharmaceuticals (i.e. nanocrystalline drugs and nanocarrier drugs) are designed using different types of materials or bioactive molecules, so as to improve the therapeutic effects, reduce side effects, and subtly deliver drugs, etc. Currently, an increasing number of nanopharmaceutical products have been approved by drug regulatory agencies, which has also prompted more researchers to focus on the potential treatment strategies of SCI. Therefore, the purpose of this review is to summarize and elaborate the research progress as well as the challenges and future of nanopharmaceuticals in the treatment of SCI, aiming to promote further research of nanopharmaceuticals in SCI.
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Affiliation(s)
- Chen Zhao
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Centre for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100191, P. R. China. and School of Pharmaceutical Sciences, Tsinghua University, Beijing, 100084, P. R. China
| | - Zheng Xing
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Centre for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100191, P. R. China.
| | - Chunchen Zhang
- Key Laboratory for Biomedical Engineering of Education Ministry of China, Zhejiang University, Hangzhou, 310027, P. R. China and Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Zhejiang University, Hangzhou, 310027, P. R. China
| | - Yubo Fan
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Centre for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100191, P. R. China.
| | - Haifeng Liu
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Centre for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100191, P. R. China.
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Li L, Ni L, Heary RF, Elkabes S. Astroglial TLR9 antagonism promotes chemotaxis and alternative activation of macrophages via modulation of astrocyte-derived signals: implications for spinal cord injury. J Neuroinflammation 2020; 17:73. [PMID: 32098620 PMCID: PMC7041103 DOI: 10.1186/s12974-020-01748-x] [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] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 02/13/2020] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND The recruitment of immune system cells into the central nervous system (CNS) has a profound effect on the outcomes of injury and disease. Glia-derived chemoattractants, including chemokines, play a pivotal role in this process. In addition, cytokines and chemokines influence the phenotype of infiltrating immune cells. Depending on the stimuli present in the local milieu, infiltrating macrophages acquire the classically activated M1 or alternatively activated M2 phenotypes. The polarization of macrophages into detrimental M1 versus beneficial M2 phenotypes significantly influences CNS pathophysiology. Earlier studies indicated that a toll-like receptor 9 (TLR9) antagonist modulates astrocyte-derived cytokine and chemokine release. However, it is not known whether these molecular changes affect astrocyte-induced chemotaxis and polarization of macrophages. The present studies were undertaken to address these issues. METHODS The chemotaxis and polarization of mouse peritoneal macrophages by spinal cord astrocytes were evaluated in a Transwell co-culture system. Arrays and ELISA were utilized to quantify chemokines in the conditioned medium (CM) of pure astrocyte cultures. Immunostaining for M1- and M2-specific markers characterized the macrophage phenotype. The percentage of M2 macrophages at the glial scar was determined by stereological approaches in mice sustaining a mid-thoracic spinal cord contusion injury (SCI) and intrathecally treated with oligodeoxynucleotide 2088 (ODN 2088), the TLR9 antagonist. Statistical analyses used two-tailed independent-sample t-test and one-way analysis of variance (ANOVA) followed by Tukey's post hoc test. A p value < 0.05 was considered to be statistically significant. RESULTS ODN 2088-treated astrocytes significantly increased the chemotaxis of peritoneal macrophages via release of chemokine (C-C motif) ligand 1 (CCL1). Vehicle-treated astrocytes polarized macrophages into the M2 phenotype and ODN 2088-treated astrocytes promoted further M2 polarization. Reduced CCL2 and CCL9 release by astrocytes in response to ODN 2088 facilitated the acquisition of the M2 phenotype, suggesting that CCL2 and CCL9 are negative regulators of M2 polarization. The percentage of M2 macrophages at the glial scar was higher in mice sustaining a SCI and receiving ODN 2088 treatment as compared to vehicle-treated injured controls. CONCLUSIONS TLR9 antagonism could create a favorable environment during SCI by supporting M2 macrophage polarization and chemotaxis via modulation of astrocyte-to-macrophage signals.
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Affiliation(s)
- Lun Li
- Reynolds Family Spine Laboratory, Department of Neurosurgery, New Jersey Medical School, Rutgers, The State University of New Jersey, 205 South Orange Avenue, F-1204, Newark, NJ 07103 USA
| | - Li Ni
- Reynolds Family Spine Laboratory, Department of Neurosurgery, New Jersey Medical School, Rutgers, The State University of New Jersey, 205 South Orange Avenue, F-1204, Newark, NJ 07103 USA
| | - Robert F. Heary
- Reynolds Family Spine Laboratory, Department of Neurosurgery, New Jersey Medical School, Rutgers, The State University of New Jersey, 205 South Orange Avenue, F-1204, Newark, NJ 07103 USA
| | - Stella Elkabes
- Reynolds Family Spine Laboratory, Department of Neurosurgery, New Jersey Medical School, Rutgers, The State University of New Jersey, 205 South Orange Avenue, F-1204, Newark, NJ 07103 USA
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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: 10] [Impact Index Per Article: 2.0] [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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Toll-like receptor 9 antagonism modulates astrocyte function and preserves proximal axons following spinal cord injury. Brain Behav Immun 2019; 80:328-343. [PMID: 30953770 DOI: 10.1016/j.bbi.2019.04.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 03/14/2019] [Accepted: 04/02/2019] [Indexed: 02/07/2023] Open
Abstract
Increasing evidence indicates that innate immune receptors play important, yet controversial, roles in traumatic central nervous system (CNS) injury. Despite many advances, the contributions of toll-like receptors (TLRs) to spinal cord injury (SCI) remain inadequately defined. We previously reported that a toll-like receptor 9 (TLR9) antagonist, oligodeoxynucleotide 2088 (ODN 2088), administered intrathecally, improves the functional and histopathological outcomes of SCI. However, the molecular and cellular changes that occur at the injury epicenter following ODN 2088 treatment are not completely understood. Following traumatic SCI, a glial scar, consisting primarily of proliferating reactive astrocytes, forms at the injury epicenter and assumes both beneficial and detrimental roles. Increased production of chondroitin sulfate proteoglycans (CSPGs) by reactive astrocytes inhibits the regeneration of injured axons. Astrocytes express TLR9, which can be activated by endogenous ligands released by damaged cells. It is not yet known how TLR9 antagonism modifies astrocyte function at the glial scar and how this affects axonal preservation or re-growth following SCI. The present studies were undertaken to address these issues. We report that in female mice sustaining a severe mid-thoracic (T8) contusion injury, the number of proliferating astrocytes in regions rostral and caudal to the lesion border increased significantly by 30- and 24-fold, respectively, compared to uninjured controls. Intrathecal ODN 2088 treatment significantly reduced the number of proliferating astrocytes by 60% in both regions. This effect appeared to be, at least partly, mediated through the direct actions of ODN 2088 on astrocytes, since the antagonist decreased proliferation in pure SC astrocyte cultures by preventing the activation of the Erk/MAPK signaling pathway. In addition, CSPG immunoreactivity at the lesion border was more pronounced in vehicle-treated injured mice compared to uninjured controls and was significantly reduced following administration of ODN 2088 to injured mice. Moreover, ODN 2088 significantly decreased astrocyte migration in an in vitro scratch-wound assay. Anterograde tracing and quantification of corticospinal tract (CST) axons in injured mice, indicated that ODN 2088 preserves proximal axons. Taken together, these findings suggest that ODN 2088 modifies the glial scar and creates a milieu that fosters axonal protection at the injury site.
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