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Abstract
Neuropathic pain is a debilitating form of pain arising from injury or disease of the nervous system that affects millions of people worldwide. Despite its prevalence, the underlying mechanisms of neuropathic pain are still not fully understood. Dendritic spines are small protrusions on the surface of neurons that play an important role in synaptic transmission. Recent studies have shown that dendritic spines reorganize in the superficial and deeper laminae of the spinal cord dorsal horn with the development of neuropathic pain in multiple models of disease or injury. Given the importance of dendritic spines in synaptic transmission, it is possible that studying dendritic spines could lead to new therapeutic approaches for managing intractable pain. In this review article, we highlight the emergent role of dendritic spines in neuropathic pain, as well as discuss the potential for studying dendritic spines for the development of new therapeutics.
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Affiliation(s)
- Curtis A Benson
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT, USA
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA
| | - Jared F King
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT, USA
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA
| | - Marike L Reimer
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT, USA
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA
| | - Sierra D Kauer
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT, USA
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA
| | - Stephen G Waxman
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT, USA
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA
| | - Andrew M Tan
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT, USA
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA
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Wu Q, Cai C, Ying X, Zheng Y, Yu J, Gu X, Tu W, Lou X, Yang G, Li M, Jiang S. Electroacupuncture inhibits dendritic spine remodeling through the srGAP3-Rac1 signaling pathway in rats with SNL. Biol Res 2023; 56:26. [PMID: 37211600 DOI: 10.1186/s40659-023-00439-0] [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: 11/08/2022] [Accepted: 05/10/2023] [Indexed: 05/23/2023] Open
Abstract
Previous studies have shown that peripheral nerve injury can lead to abnormal dendritic spine remodeling in spinal dorsal horn neurons. Inhibition of abnormal dendritic spine remodeling can relieve neuropathic pain. Electroacupuncture (EA) has a beneficial effect on the treatment of neuropathic pain, but the specific mechanism remains unclear. Evidence has shown that slit-robo GTPase activating protein 3 (srGAP3) and Rho GTPase (Rac1) play very important roles in dendritic spine remodeling. Here, we used srGAP3 siRNA and Rac1 activator CN04 to confirm the relationship between SrGAP3 and Rac1 and their roles in improving neuropathic pain with EA. Spinal nerve ligation (SNL) was used as the experimental model, and thermal withdrawal latency (TWL), mechanical withdrawal threshold (MWT), Western blotting, immunohistochemistry and Golgi-Cox staining were used to examine changes in behavioral performance, protein expression and dendritic spines. More dendritic spines and higher expression levels of srGAP3 were found in the initial phase of neuropathic pain. During the maintenance phase, dendritic spines were more mature, which was consistent with lower expression levels of srGAP3 and higher expression levels of Rac1-GTP. EA during the maintenance phase reduced the density and maturity of dendritic spines of rats with SNL, increased the levels of srGAP3 and reduced the levels of Rac1-GTP, while srGAP3 siRNA and CN04 reversed the therapeutic effects of EA. These results suggest that dendritic spines have different manifestations in different stages of neuropathic pain and that EA may inhibit the abnormal dendritic spine remodeling by regulating the srGAP3/Rac1 signaling pathway to alleviate neuropathic pain.
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Affiliation(s)
- Qiaoyun Wu
- Department of Physical Medicine and Rehabilitation, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, 268 Xue Yuan Xi Road, Wenzhou, 325027, Zhejiang, People's Republic of China
- Integrative and Optimized Medicine Research Center, China-USA Institute for Acupuncture and Rehabilitation, Wenzhou Medical University, Wenzhou, 325027, Zhejiang, China
- The Wenzhou Key Laboratory for Rehabilitation Research, The Provincial Key Laboratory for Acupuncture and Rehabilitation in Zhejiang Province, Wenzhou, China
| | - Chenchen Cai
- Department of Physical Medicine and Rehabilitation, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, 268 Xue Yuan Xi Road, Wenzhou, 325027, Zhejiang, People's Republic of China
- Integrative and Optimized Medicine Research Center, China-USA Institute for Acupuncture and Rehabilitation, Wenzhou Medical University, Wenzhou, 325027, Zhejiang, China
- The Wenzhou Key Laboratory for Rehabilitation Research, The Provincial Key Laboratory for Acupuncture and Rehabilitation in Zhejiang Province, Wenzhou, China
| | - Xinwang Ying
- Department of Physical Medicine and Rehabilitation, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, 268 Xue Yuan Xi Road, Wenzhou, 325027, Zhejiang, People's Republic of China
- Integrative and Optimized Medicine Research Center, China-USA Institute for Acupuncture and Rehabilitation, Wenzhou Medical University, Wenzhou, 325027, Zhejiang, China
- The Wenzhou Key Laboratory for Rehabilitation Research, The Provincial Key Laboratory for Acupuncture and Rehabilitation in Zhejiang Province, Wenzhou, China
| | - Yujun Zheng
- Department of Physical Medicine and Rehabilitation, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, 268 Xue Yuan Xi Road, Wenzhou, 325027, Zhejiang, People's Republic of China
- Integrative and Optimized Medicine Research Center, China-USA Institute for Acupuncture and Rehabilitation, Wenzhou Medical University, Wenzhou, 325027, Zhejiang, China
- The Wenzhou Key Laboratory for Rehabilitation Research, The Provincial Key Laboratory for Acupuncture and Rehabilitation in Zhejiang Province, Wenzhou, China
| | - Jiaying Yu
- Department of Physical Medicine and Rehabilitation, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, 268 Xue Yuan Xi Road, Wenzhou, 325027, Zhejiang, People's Republic of China
- Integrative and Optimized Medicine Research Center, China-USA Institute for Acupuncture and Rehabilitation, Wenzhou Medical University, Wenzhou, 325027, Zhejiang, China
- The Wenzhou Key Laboratory for Rehabilitation Research, The Provincial Key Laboratory for Acupuncture and Rehabilitation in Zhejiang Province, Wenzhou, China
| | - Xiaoxue Gu
- Department of Physical Medicine and Rehabilitation, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, 268 Xue Yuan Xi Road, Wenzhou, 325027, Zhejiang, People's Republic of China
- Integrative and Optimized Medicine Research Center, China-USA Institute for Acupuncture and Rehabilitation, Wenzhou Medical University, Wenzhou, 325027, Zhejiang, China
- The Wenzhou Key Laboratory for Rehabilitation Research, The Provincial Key Laboratory for Acupuncture and Rehabilitation in Zhejiang Province, Wenzhou, China
| | - Wenzhan Tu
- Department of Physical Medicine and Rehabilitation, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, 268 Xue Yuan Xi Road, Wenzhou, 325027, Zhejiang, People's Republic of China
- Integrative and Optimized Medicine Research Center, China-USA Institute for Acupuncture and Rehabilitation, Wenzhou Medical University, Wenzhou, 325027, Zhejiang, China
- The Wenzhou Key Laboratory for Rehabilitation Research, The Provincial Key Laboratory for Acupuncture and Rehabilitation in Zhejiang Province, Wenzhou, China
| | - Xinfa Lou
- Integrative and Optimized Medicine Research Center, China-USA Institute for Acupuncture and Rehabilitation, Wenzhou Medical University, Wenzhou, 325027, Zhejiang, China
| | - Guanhu Yang
- Department of Physical Medicine and Rehabilitation, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, 268 Xue Yuan Xi Road, Wenzhou, 325027, Zhejiang, People's Republic of China
- Integrative and Optimized Medicine Research Center, China-USA Institute for Acupuncture and Rehabilitation, Wenzhou Medical University, Wenzhou, 325027, Zhejiang, China
- The Wenzhou Key Laboratory for Rehabilitation Research, The Provincial Key Laboratory for Acupuncture and Rehabilitation in Zhejiang Province, Wenzhou, China
| | - Ming Li
- School of Basic Medical Science, Wenzhou Medical University, Wenzhou, 325027, Zhejiang, China
- The Wenzhou Key Laboratory for Rehabilitation Research, The Provincial Key Laboratory for Acupuncture and Rehabilitation in Zhejiang Province, Wenzhou, China
| | - Songhe Jiang
- Department of Physical Medicine and Rehabilitation, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, 268 Xue Yuan Xi Road, Wenzhou, 325027, Zhejiang, People's Republic of China.
- Integrative and Optimized Medicine Research Center, China-USA Institute for Acupuncture and Rehabilitation, Wenzhou Medical University, Wenzhou, 325027, Zhejiang, China.
- The Wenzhou Key Laboratory for Rehabilitation Research, The Provincial Key Laboratory for Acupuncture and Rehabilitation in Zhejiang Province, Wenzhou, China.
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Xu L, Yang L, Wu Y, Wan X, Tang X, Xu Y, Chen Q, Liu Y, Liu S. Rac1/PAK1 signaling contributes to bone cancer pain by Regulation dendritic spine remodeling in rats. Mol Pain 2023; 19:17448069231161031. [PMID: 36938611 PMCID: PMC10028669 DOI: 10.1177/17448069231161031] [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] [Indexed: 03/21/2023] Open
Abstract
Bone cancer pain (BCP) is severe chronic pain caused by tumor metastasis to the bones, often resulting in significant skeletal remodeling and fractures. Currently, there is no curative treatment. Therefore, insight into the underlying mechanisms could guide the development of mechanism-based therapeutic strategies for BCP. We speculated that Rac1/PAK1 signaling plays a critical role in the development of BCP. Tumor cells implantation (TCI) into the tibial cavity resulted in bone cancer-associated mechanical allodynia. Golgi staining revealed changes in the excitatory synaptic structure of WDR (Wide-dynamic range) neurons in the spinal cord, including increased postsynaptic density (PSD) length and thickness, and width of the cleft. Behavioral and western blotting test revealed that the development and persistence of pain correlated with Rac1/PAK1 signaling activation in primary sensory neurons. Intrathecal injection of NSC23766, a Rac1 inhibitor, reduced the persistence of BCP as well as reversed the remodeling of dendrites. Therefore, we concluded that activation of the Rac1/PAK1 signaling pathway in the spinal cord plays an important role in the development of BCP through remodeling of dendritic spines. Modulation of the Rac1/PAK1 pathway may be a potential strategy for BCP treatment.
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Affiliation(s)
- Lingfei Xu
- Jiangsu Province Key Laboratory of
Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia
Application Technology, NMPA Key Laboratory for Research and Evaluation of
Narcotic and Psychotropic Drugs, Xuzhou Medical
University, Jiangsu, China
| | - Long Yang
- Jiangsu Province Key Laboratory of
Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia
Application Technology, NMPA Key Laboratory for Research and Evaluation of
Narcotic and Psychotropic Drugs, Xuzhou Medical
University, Jiangsu, China
| | - Yan Wu
- Jiangsu Province Key Laboratory of
Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia
Application Technology, NMPA Key Laboratory for Research and Evaluation of
Narcotic and Psychotropic Drugs, Xuzhou Medical
University, Jiangsu, China
- Department of Anesthesiology, The Affiliated Hospital of Xuzhou
Medical University, Jiangsu, China
| | - Xinxin Wan
- Department of Anesthesiology, Nanjing Drum Tower
Hospital, Jiangsu, China
| | - Xihui Tang
- Jiangsu Province Key Laboratory of
Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia
Application Technology, NMPA Key Laboratory for Research and Evaluation of
Narcotic and Psychotropic Drugs, Xuzhou Medical
University, Jiangsu, China
- Department of Anesthesiology, The Affiliated Hospital of Xuzhou
Medical University, Jiangsu, China
| | - Yuqing Xu
- Jiangsu Province Key Laboratory of
Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia
Application Technology, NMPA Key Laboratory for Research and Evaluation of
Narcotic and Psychotropic Drugs, Xuzhou Medical
University, Jiangsu, China
- Department of Anesthesiology, The Affiliated Hospital of Xuzhou
Medical University, Jiangsu, China
| | - Qingsong Chen
- Jiangsu Province Key Laboratory of
Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia
Application Technology, NMPA Key Laboratory for Research and Evaluation of
Narcotic and Psychotropic Drugs, Xuzhou Medical
University, Jiangsu, China
- Department of Anesthesiology, The Affiliated Hospital of Xuzhou
Medical University, Jiangsu, China
| | - Yuepeng Liu
- Institute of Xuzhou Medical
Science, Jiangsu, China
| | - Su Liu
- Jiangsu Province Key Laboratory of
Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia
Application Technology, NMPA Key Laboratory for Research and Evaluation of
Narcotic and Psychotropic Drugs, Xuzhou Medical
University, Jiangsu, China
- Department of Anesthesiology, The Affiliated Hospital of Xuzhou
Medical University, Jiangsu, China
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Buprenorphine, a partial opioid agonist, prevents modulation of H-reflex induced by pulsed electromagnetic stimulation in spinal cord injured rats. Neurosci Lett 2022; 777:136583. [DOI: 10.1016/j.neulet.2022.136583] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 03/16/2022] [Accepted: 03/17/2022] [Indexed: 11/24/2022]
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The Role of Body in Brain Plasticity. Brain Sci 2022; 12:brainsci12020277. [PMID: 35204040 PMCID: PMC8869932 DOI: 10.3390/brainsci12020277] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 02/12/2022] [Indexed: 12/14/2022] Open
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Leemhuis E, Giuffrida V, De Martino ML, Forte G, Pecchinenda A, De Gennaro L, Giannini AM, Pazzaglia M. Rethinking the Body in the Brain after Spinal Cord Injury. J Clin Med 2022; 11:jcm11020388. [PMID: 35054089 PMCID: PMC8780443 DOI: 10.3390/jcm11020388] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2021] [Accepted: 01/12/2022] [Indexed: 02/05/2023] Open
Abstract
Spinal cord injuries (SCI) are disruptive neurological events that severly affect the body leading to the interruption of sensorimotor and autonomic pathways. Recent research highlighted SCI-related alterations extend beyond than the expected network, involving most of the central nervous system and goes far beyond primary sensorimotor cortices. The present perspective offers an alternative, useful way to interpret conflicting findings by focusing on the deafferented and deefferented body as the central object of interest. After an introduction to the main processes involved in reorganization according to SCI, we will focus separately on the body regions of the head, upper limbs, and lower limbs in complete, incomplete, and deafferent SCI participants. On one hand, the imprinting of the body’s spatial organization is entrenched in the brain such that its representation likely lasts for the entire lifetime of patients, independent of the severity of the SCI. However, neural activity is extremely adaptable, even over short time scales, and is modulated by changing conditions or different compensative strategies. Therefore, a better understanding of both aspects is an invaluable clinical resource for rehabilitation and the successful use of modern robotic technologies.
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Affiliation(s)
- Erik Leemhuis
- Department of Psychology, Sapienza University of Rome, Via dei Marsi 78, 00185 Rome, Italy; (E.L.); (V.G.); (M.L.D.M.); (A.P.); (L.D.G.); (A.M.G.)
- Action and Body Lab, IRCCS Fondazione Santa Lucia, Via Ardeatina 306, 00179 Rome, Italy
| | - Valentina Giuffrida
- Department of Psychology, Sapienza University of Rome, Via dei Marsi 78, 00185 Rome, Italy; (E.L.); (V.G.); (M.L.D.M.); (A.P.); (L.D.G.); (A.M.G.)
- Action and Body Lab, IRCCS Fondazione Santa Lucia, Via Ardeatina 306, 00179 Rome, Italy
| | - Maria Luisa De Martino
- Department of Psychology, Sapienza University of Rome, Via dei Marsi 78, 00185 Rome, Italy; (E.L.); (V.G.); (M.L.D.M.); (A.P.); (L.D.G.); (A.M.G.)
- Action and Body Lab, IRCCS Fondazione Santa Lucia, Via Ardeatina 306, 00179 Rome, Italy
| | - Giuseppe Forte
- Department of Psychology, Sapienza University of Rome, Via dei Marsi 78, 00185 Rome, Italy; (E.L.); (V.G.); (M.L.D.M.); (A.P.); (L.D.G.); (A.M.G.)
- Action and Body Lab, IRCCS Fondazione Santa Lucia, Via Ardeatina 306, 00179 Rome, Italy
- Correspondence: (G.F.); (M.P.); Tel.: +39-6-49917633 (M.P.)
| | - Anna Pecchinenda
- Department of Psychology, Sapienza University of Rome, Via dei Marsi 78, 00185 Rome, Italy; (E.L.); (V.G.); (M.L.D.M.); (A.P.); (L.D.G.); (A.M.G.)
| | - Luigi De Gennaro
- Department of Psychology, Sapienza University of Rome, Via dei Marsi 78, 00185 Rome, Italy; (E.L.); (V.G.); (M.L.D.M.); (A.P.); (L.D.G.); (A.M.G.)
- Action and Body Lab, IRCCS Fondazione Santa Lucia, Via Ardeatina 306, 00179 Rome, Italy
| | - Anna Maria Giannini
- Department of Psychology, Sapienza University of Rome, Via dei Marsi 78, 00185 Rome, Italy; (E.L.); (V.G.); (M.L.D.M.); (A.P.); (L.D.G.); (A.M.G.)
| | - Mariella Pazzaglia
- Department of Psychology, Sapienza University of Rome, Via dei Marsi 78, 00185 Rome, Italy; (E.L.); (V.G.); (M.L.D.M.); (A.P.); (L.D.G.); (A.M.G.)
- Action and Body Lab, IRCCS Fondazione Santa Lucia, Via Ardeatina 306, 00179 Rome, Italy
- Correspondence: (G.F.); (M.P.); Tel.: +39-6-49917633 (M.P.)
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Duman JG, Blanco FA, Cronkite CA, Ru Q, Erikson KC, Mulherkar S, Saifullah AB, Firozi K, Tolias KF. Rac-maninoff and Rho-vel: The symphony of Rho-GTPase signaling at excitatory synapses. Small GTPases 2022; 13:14-47. [PMID: 33955328 PMCID: PMC9707551 DOI: 10.1080/21541248.2021.1885264] [Citation(s) in RCA: 8] [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: 10/28/2020] [Revised: 01/22/2021] [Accepted: 01/28/2021] [Indexed: 01/15/2023] Open
Abstract
Synaptic connections between neurons are essential for every facet of human cognition and are thus regulated with extreme precision. Rho-family GTPases, molecular switches that cycle between an active GTP-bound state and an inactive GDP-bound state, comprise a critical feature of synaptic regulation. Rho-GTPases are exquisitely controlled by an extensive suite of activators (GEFs) and inhibitors (GAPs and GDIs) and interact with many different signalling pathways to fulfill their roles in orchestrating the development, maintenance, and plasticity of excitatory synapses of the central nervous system. Among the mechanisms that control Rho-GTPase activity and signalling are cell surface receptors, GEF/GAP complexes that tightly regulate single Rho-GTPase dynamics, GEF/GAP and GEF/GEF functional complexes that coordinate multiple Rho-family GTPase activities, effector positive feedback loops, and mutual antagonism of opposing Rho-GTPase pathways. These complex regulatory mechanisms are employed by the cells of the nervous system in almost every step of development, and prominently figure into the processes of synaptic plasticity that underlie learning and memory. Finally, misregulation of Rho-GTPases plays critical roles in responses to neuronal injury, such as traumatic brain injury and neuropathic pain, and in neurodevelopmental and neurodegenerative disorders, including intellectual disability, autism spectrum disorder, schizophrenia, and Alzheimer's Disease. Thus, decoding the mechanisms of Rho-GTPase regulation and function at excitatory synapses has great potential for combatting many of the biggest current challenges in mental health.
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Affiliation(s)
- Joseph G. Duman
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Francisco A. Blanco
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- Integrative Molecular and Biomedical Science Graduate Program, Baylor College of Medicine, Houston, TX, USA
| | - Christopher A. Cronkite
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA
- Medical Scientist Training Program, Baylor College of Medicine, Houston, TX, USA
| | - Qin Ru
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Kelly C. Erikson
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Shalaka Mulherkar
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Ali Bin Saifullah
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Karen Firozi
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Kimberley F. Tolias
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA
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Beating Pain with Psychedelics: Matter over Mind? Neurosci Biobehav Rev 2021; 134:104482. [PMID: 34922987 DOI: 10.1016/j.neubiorev.2021.12.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 11/19/2021] [Accepted: 12/04/2021] [Indexed: 02/08/2023]
Abstract
Basic pain research has shed light on key cellular and molecular mechanisms underlying nociceptive and phenomenological aspects of pain. Despite these advances, [[we still yearn for] the discovery of novel therapeutic strategies to address the unmet needs of about 70% of chronic neuropathic pain patients whose pain fails to respond to opioids as well as to other conventional analgesic agents. Importantly, a substantial body of clinical observations over the past decade cumulatively suggests that the psychedelic class of drugs may possess heuristic value for understanding and treating chronic pain conditions. The present review presents a theoretical framework for hitherto insufficiently understood neuroscience-based mechanisms of psychedelics' potential analgesic effects. To that end, searches of PubMed-indexed journals were performed using the following Medical Subject Headings' terms: pain, analgesia, inflammatory, brain connectivity, ketamine, psilocybin, functional imaging, and dendrites. Recursive sets of scientific and clinical evidence extracted from this literature review were summarized within the following key areas: (1) studies employing psychedelics for alleviation of physical and emotional pain; (2) potential neuro-restorative effects of psychedelics to remediate the impaired connectivity underlying the dissociation between pain-related conscious states/cognitions and the subcortical activity/function leading to the eventual chronicity through immediate and long-term effects on dentritic plasticity; (3) anti-neuroinflammatory and pro-immunomodulatory actions of psychedelics as the may pertain to the role of these factors in the pathogenesis of neuropathic pain; (4) safety, legal, and ethical consideration inherent in psychedelics' pharmacotherapy. In addition to direct beneficial effects in terms of reduction of pain and suffering, psychedelics' inclusion in the analgesic armamentarium will contribute to deeper and more sophisticated insights not only into pain syndromes but also into frequently comorbid psychiatric condition associated with emotional pain, e.g., depressive and anxiety disorders. Further inquiry is clearly warranted into the above areas that have potential to evolve into further elucidate the mechanisms of chronic pain and affective disorders, and lead to the development of innovative, safe, and more efficacious neurobiologically-based therapeutic approaches.
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Li S, Zhao F, Tang Q, Xi C, He J, Wang Y, Zhu MX, Cao Z. Sarco/endoplasmic reticulum Ca 2+ -ATPase 2b mediates oxidation-induced endoplasmic reticulum stress to regulate neuropathic pain. Br J Pharmacol 2021; 179:2016-2036. [PMID: 34811737 DOI: 10.1111/bph.15744] [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: 08/16/2021] [Revised: 09/24/2021] [Accepted: 11/05/2021] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE Neuropathic pain is a widespread health problem with limited curative treatment. Decreased sarco/endoplasmic reticulum Ca2+ -ATPase (SERCA) expression has been reported in dorsal root ganglion (DRG) of animals suffering from neuropathic pain. We aimed to establish the relationship between SERCA expression and the pain responses and to elucidate the underlying molecular mechanism. EXPERIMENTAL APPROACH Neuropathic pain was modeled using rat chronic constriction injury (CCI). Ca2+ imaging and current clamp patch-clamp were used to determine cytosolic Ca2+ levels and action potential firing, respectively. Western blots, immunofluorescence staining and RT-PCR were used to quantitatively assess protein and mRNA expression, respectively. H&E staining and coupled enzyme assay were used to evaluate the nerve injury and SERCA2b activity, respectively. KEY RESULTS SERCA2b is the predominant SERCA isoform in rat DRG and its expression is decreased after CCI at mRNA, protein and activity levels. Whereas inhibiting SERCA with thapsigargin causes neuronal hyperexcitation, nerve injury, ER stress, satellite glial cell activation and mechanical allodynia, activating SERCA by CDN1163 or overexpressing SERCA2b in DRG after CCI produces long-term relief of mechanical and thermal allodynia with accompanied morphological and functional restoration through alleviation of ER stress. Furthermore, the downregulation of DRG SERCA2b in CCI rats is caused by increased production of reactive oxygen species (ROS) through Sp1-dependent transcriptional inhibition. CONCLUSION AND IMPLICATIONS Our findings reveal a novel pathway centering around SERCA2b as the key molecule underlying the mechanism of development and maintenance of neuropathic pain, and SERCA2b activators have the potential for therapeutic treatment of neuropathic pain.
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Affiliation(s)
- Shaoheng Li
- State Key Laboratory of Natural Medicines and Jiangsu Provincial Key Laboratory for TCM Evaluation and Translational Development, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, China
| | - Fang Zhao
- State Key Laboratory of Natural Medicines and Jiangsu Provincial Key Laboratory for TCM Evaluation and Translational Development, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, China
| | - Qinglian Tang
- State Key Laboratory of Natural Medicines and Jiangsu Provincial Key Laboratory for TCM Evaluation and Translational Development, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, China
| | - Chuchu Xi
- State Key Laboratory of Natural Medicines and Jiangsu Provincial Key Laboratory for TCM Evaluation and Translational Development, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, China
| | - Jing He
- State Key Laboratory of Natural Medicines and Jiangsu Provincial Key Laboratory for TCM Evaluation and Translational Development, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, China
| | - Yujing Wang
- State Key Laboratory of Natural Medicines and Jiangsu Provincial Key Laboratory for TCM Evaluation and Translational Development, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, China
| | - Michael X Zhu
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Zhengyu Cao
- State Key Laboratory of Natural Medicines and Jiangsu Provincial Key Laboratory for TCM Evaluation and Translational Development, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, China
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Yang X, Zhu L, Zhao B, Hu J, Deng F, Lei S, Yao ZW, Liu K. Screening and Identification of Key Genes, Pathways, and Drugs Associated with Neuropathic Pain in Dorsal Horn: Evidence from Bioinformatic Analysis. J Pain Res 2021; 14:1813-1826. [PMID: 34168490 PMCID: PMC8217596 DOI: 10.2147/jpr.s312117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Accepted: 05/20/2021] [Indexed: 11/23/2022] Open
Abstract
Purpose Neuropathic pain is a devastating complex condition occurring post-nervous system damage. Microglia in dorsal horn drives neuropathic pain as a kind of immune cell. We aimed to find potential differentially expressed genes (DEGs) and candidate pathways, which induced neuropathic pain, and to identify some new transcription factors and therapeutic drugs via bioinformatic analysis. Methods The microarray profile GSE60670 was downloaded and analyzed. DEGs were screened and analyzed through Gene Ontology (GO), pathway enrichment, and protein-to-protein interaction (PPI) network. Respectively, transcription factors (TFs) and potential therapeutic drugs for DEGs were predicted through NetworkAnalyst and DGIdb databases. At last, we chose top 10 DEGs for external validation. Results A total of 100 DEGs were identified. The results of pathway and GO analyses were closely related to malaria inflammatory pathway and inflammatory response. Three necessary PPI modules and 9 hub genes were identified in PPI analysis, and 277 DEG-TF pairs were found among 54 DEGs and 32 TF. Moreover, 22 candidate drugs were found to match 9 hub genes. External validation of 9 of the top 10 DEGs were consistent with bioinformatic analysis. Conclusion This study provided comprehensive analyses for the functional gene sets and pathways related to neuropathic pain and promoted our understanding of the mechanism or therapy of neuropathic pain.
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Affiliation(s)
- Xiao Yang
- Department of Anesthesiology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, People's Republic of China
| | - Lin Zhu
- Department of Anesthesiology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, People's Republic of China
| | - Bingcheng Zhao
- Department of Anesthesiology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, People's Republic of China
| | - Jingjuan Hu
- Department of Anesthesiology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, People's Republic of China
| | - Fan Deng
- Department of Anesthesiology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, People's Republic of China
| | - Shaohui Lei
- Department of Anesthesiology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, People's Republic of China
| | - Zhi-Wen Yao
- Department of Anesthesiology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, People's Republic of China
| | - Kexuan Liu
- Department of Anesthesiology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, People's Republic of China
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11
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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: 15] [Impact Index Per Article: 5.0] [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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12
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Conditional RAC1 knockout in motor neurons restores H-reflex rate-dependent depression after spinal cord injury. Sci Rep 2021; 11:7838. [PMID: 33837249 PMCID: PMC8035187 DOI: 10.1038/s41598-021-87476-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 03/30/2021] [Indexed: 12/27/2022] Open
Abstract
A major complication with spinal cord injury (SCI) is the development of spasticity, a clinical symptom of hyperexcitability within the spinal H-reflex pathway. We have previously demonstrated a common structural motif of dendritic spine dysgenesis associated with hyperexcitability disorders after injury or disease insults to the CNS. Here, we used an adeno-associated viral (AAV)-mediated Cre-Lox system to knockout Rac1 protein expression in motor neurons after SCI. Three weeks after AAV9-Cre delivery into the soleus/gastrocnemius of Rac1-“floxed” adult mice to retrogradely infect spinal alpha-motor neurons, we observed significant restoration of RDD and reduced H-reflex excitability in SCI animals. Additionally, viral-mediated Rac1 knockdown reduced presence of dendritic spine dysgenesis on motor neurons. In control SCI animals without Rac1 knockout, we continued to observe abnormal dendritic spine morphology associated with hyperexcitability disorder, including an increase in mature, mushroom dendritic spines, and an increase in overall spine length and spine head size. Taken together, our results demonstrate that viral-mediated disruption of Rac1 expression in ventral horn motor neurons can mitigate dendritic spine morphological correlates of neuronal hyperexcitability, and reverse hyperreflexia associated with spasticity after SCI. Finally, our findings provide evidence of a putative mechanistic relationship between motor neuron dendritic spine dysgenesis and SCI-induced spasticity.
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13
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Sculpting Dendritic Spines during Initiation and Maintenance of Neuropathic Pain. J Neurosci 2021; 40:7578-7589. [PMID: 32998955 DOI: 10.1523/jneurosci.1664-20.2020] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/31/2020] [Accepted: 08/21/2020] [Indexed: 12/21/2022] Open
Abstract
Accumulating evidence has established a firm role for synaptic plasticity in the pathogenesis of neuropathic pain. Recent advances have highlighted the importance of dendritic spine remodeling in driving synaptic plasticity within the CNS. Identifying the molecular players underlying neuropathic pain induced structural and functional maladaptation is therefore critical to understanding its pathophysiology. This process of dynamic reorganization happens in unique phases that have diverse pathologic underpinnings in the initiation and maintenance of neuropathic pain. Recent evidence suggests that pharmacological targeting of specific proteins during distinct phases of neuropathic pain development produces enhanced antinociception. These findings outline a potential new paradigm for targeted treatment and the development of novel therapies for neuropathic pain. We present a concise review of the role of dendritic spines in neuropathic pain and outline the potential for modulation of spine dynamics by targeting two proteins, srGAP3 and Rac1, critically involved in the regulation of the actin cytoskeleton.
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14
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Benson CA, Reimer ML, Tan AM. Dendritic Spines in the Spinal Cord: Live Action Pain. Neurosci Insights 2020; 15:2633105520951164. [PMID: 32864619 PMCID: PMC7432977 DOI: 10.1177/2633105520951164] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 07/29/2020] [Indexed: 12/30/2022] Open
Abstract
Dendritic spines are microscopic protrusions on neurons that house the postsynaptic machinery necessary for neurotransmission between neurons. As such, dendritic spine structure is intimately linked with synaptic function. In pathology, dendritic spine behavior and its contribution to disease are not firmly understood. It is well known that dendritic spines are highly dynamic in vivo. In our recent publication, we used an intravital imaging approach, which permitted us to repeatedly visualize the same neurons located in lamina II, a nociceptive processing region of the spinal cord. Using this imaging platform, we analyzed the intravital dynamics of dendritic spine structure before and after nerve injury-induced pain. This effort revealed a time-dependent relationship between the progressive increase in pain outcome, and a switch in the steady-state fluctuations of dendritic spine structure. Collectively, our in vivo study demonstrates how injury that leads to abnormal pain may also contribute to synapse-associated structural remodeling in nociceptive regions of the spinal cord dorsal horn. By combining our live-imaging approach with measures of neuronal activity, such as with the use of calcium or other voltage-sensitive dyes, we expect to gain a more complete picture of the relationship between dendritic spine structure and nociceptive physiology.
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Affiliation(s)
- Curtis A Benson
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale School of Medicine, Yale University, New Haven, CT, USA.,Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA
| | - Marike L Reimer
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale School of Medicine, Yale University, New Haven, CT, USA.,Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA
| | - Andrew M Tan
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale School of Medicine, Yale University, New Haven, CT, USA.,Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA
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15
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Kober KM, Schumacher M, Conley YP, Topp K, Mazor M, Hammer MJ, Paul SM, Levine JD, Miaskowski C. Signaling pathways and gene co-expression modules associated with cytoskeleton and axon morphology in breast cancer survivors with chronic paclitaxel-induced peripheral neuropathy. Mol Pain 2020; 15:1744806919878088. [PMID: 31486345 PMCID: PMC6755139 DOI: 10.1177/1744806919878088] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Background The major dose-limiting toxicity of paclitaxel, one of the most commonly used
drugs to treat breast cancer, is peripheral neuropathy (paclitaxel-induced
peripheral neuropathy). Paclitaxel-induced peripheral neuropathy, which
persists into survivorship, has a negative impact on patient’s mood,
functional status, and quality of life. Currently, no interventions are
available to treat paclitaxel-induced peripheral neuropathy. A critical
barrier to the development of efficacious interventions is the lack of
understanding of the mechanisms that underlie paclitaxel-induced peripheral
neuropathy. While data from preclinical studies suggest that disrupting
cytoskeleton- and axon morphology-related processes are a potential
mechanism for paclitaxel-induced peripheral neuropathy, clinical evidence is
limited. The purpose of this study in breast cancer survivors was to
evaluate whether differential gene expression and co-expression patterns in
these pathways are associated with paclitaxel-induced peripheral
neuropathy. Methods Signaling pathways and gene co-expression modules associated with
cytoskeleton and axon morphology were identified between survivors who
received paclitaxel and did (n = 25) or did not (n = 25) develop
paclitaxel-induced peripheral neuropathy. Results Pathway impact analysis identified four significantly perturbed cytoskeleton-
and axon morphology-related signaling pathways. Weighted gene co-expression
network analysis identified three co-expression modules. One module was
associated with paclitaxel-induced peripheral neuropathy group membership.
Functional analysis found that this module was associated with four
signaling pathways and two ontology annotations related to cytoskeleton and
axon morphology. Conclusions This study, which is the first to apply systems biology approaches using
circulating whole blood RNA-seq data in a sample of breast cancer survivors
with and without chronic paclitaxel-induced peripheral neuropathy, provides
molecular evidence that cytoskeleton- and axon morphology-related mechanisms
identified in preclinical models of various types of neuropathic pain
including chemotherapy-induced peripheral neuropathy are found in breast
cancer survivors and suggests pathways and a module of genes for validation
and as potential therapeutic targets.
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Affiliation(s)
- Kord M Kober
- School of Nursing, University of California, San Francisco, CA, USA
| | - Mark Schumacher
- School of Medicine, University of California, San Francisco, CA, USA
| | - Yvette P Conley
- School of Nursing, University of Pittsburgh, Pittsburgh, PA, USA
| | - Kimberly Topp
- School of Medicine, University of California, San Francisco, CA, USA
| | - Melissa Mazor
- School of Nursing, University of California, San Francisco, CA, USA
| | - Marilynn J Hammer
- Icahn School of Medicine, Mount Sinai Medical Center, New York, NY, USA
| | - Steven M Paul
- School of Nursing, University of California, San Francisco, CA, USA
| | - Jon D Levine
- School of Medicine, University of California, San Francisco, CA, USA
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16
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Meehan CF, Ford TW, Kirkwood PA. Plasticity of thoracic interneurones rostral to a lateral spinal cord lesion. Exp Neurol 2020; 331:113361. [PMID: 32464119 DOI: 10.1016/j.expneurol.2020.113361] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Revised: 05/03/2020] [Accepted: 05/17/2020] [Indexed: 01/14/2023]
Abstract
The morphology and projections of ventral horn interneurones in the segment above an ipsilateral thoracic lateral spinal cord lesion were studied in the cat by intracellular injections of Neurobiotin at 6 to 18 weeks post-lesion and compared with previously published control data from uninjured spinal cords. The cell axons ascended, descended or both, mostly contralaterally and mostly spared by the lesion. Unusual morphological dendritic features were seen in the lesion group, mostly growth-related, including complex dendritic appendages, twisted or multiple-branched terminal dendrites, commissural dendrites, apparently swollen proximal dendrites and rostrocaudal asymmetries. Significant quantitative differences included more dendritic spines in the lesion group (3.4×) and smaller soma areas in the lesion group (with similar numbers of primary dendrites and rostrocaudal dendritic spans). Immunoreactivity to microtubule associated protein 2a/b was detected in the proximal, but not distal, dendrites of cells in the lesion group, corresponding to an overall decrease in immunoreactivity in the ventral horns on the lesion side compared to the other. For axon collaterals, significant increases for the lesion group were seen in the number of collaterals in the first 4 mm of axon and in the area of ventral/intermediate horn occupied by terminals, including increased innervation of some regions, among which were the intermediolateral columns. This dendritic and axonal plasticity makes the interneuones candidates for a role in detour circuits but also for a maladaptive role in autonomic hyperreflexia.
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Affiliation(s)
- Claire Francesca Meehan
- Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK.
| | - Timothy W Ford
- Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Peter A Kirkwood
- Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
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17
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Dendritic Spine Dynamics after Peripheral Nerve Injury: An Intravital Structural Study. J Neurosci 2020; 40:4297-4308. [PMID: 32371602 DOI: 10.1523/jneurosci.2858-19.2020] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 02/10/2020] [Accepted: 02/28/2020] [Indexed: 11/21/2022] Open
Abstract
Neuropathic pain is an intractable medical condition with few or no options for effective treatment. Emerging evidence shows a strong structure-function relationship between dendritic spine dysgenesis and the presence of neuropathic pain. Postmortem tissue analyses can only imply dynamic structural changes associated with injury-induced pain. Here, we profiled the in vivo dynamics of dendritic spines over time on the same superficial dorsal horn (lamina II) neurons before and after peripheral nerve injury-induced pain. We used a two-photon, whole-animal imaging paradigm that permitted repeat imaging of the same dendritic branches of these neurons in C57/Bl6 Thy1-YFP male mice. Our study demonstrates, for the first time, the ongoing, steady-state changes in dendritic spine dynamics in the dorsal horn associated with peripheral nerve injury and pain. Ultimately, the relationship between altered dendritic spine dynamics and neuropathic pain may serve as a structure-based opportunity to investigate mechanisms of pain following injury and disease.SIGNIFICANCE STATEMENT This work is important because it demonstrates for the first time: (1) the powerful utility of intravital study of dendritic spine dynamics in the superficial dorsal horn; (2) that nerve injury-induced pain triggers changes in dendritic spine steady-state behavior in the spinal cord dorsal horn; and (3) this work opens the door to further investigations in vivo of spinal cord dendritic spine dynamics in the context of injury and disease.
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18
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Chen Z, Zhang S, Nie B, Huang J, Han Z, Chen X, Bai X, Ouyang H. Distinct roles of srGAP3‐Rac1 in the initiation and maintenance phases of neuropathic pain induced by paclitaxel. J Physiol 2020; 598:2415-2430. [DOI: 10.1113/jp279525] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Accepted: 03/19/2020] [Indexed: 11/08/2022] Open
Affiliation(s)
- Zihang Chen
- Department of AnesthesiologyGuangdong Provincial key Laboratory of Malignant Tumor Epigenetics and Gene Regulation. Sun Yat‐sen Memorial HospitalSun Yat‐sen University Guangzhou China
- Department of AnesthesiologyState Key Laboratory of Oncology in Southern ChinaSun Yat‐sen University Cancer CenterCollaborative Innovation Center for Cancer Medicine Guangzhou China
- Zhongshan School of MedicineSun Yat‐sen University Guangzhou China
| | - Subo Zhang
- Department of Rehabilitation MedicineSun Yat‐sen Memorial HospitalSun Yat‐sen University Guangzhou China
| | - Bilin Nie
- Department of AnesthesiologyGuangdong Women and Children Hospital Guangzhou China
| | - Jingxiu Huang
- Department of AnesthesiologyState Key Laboratory of Oncology in Southern ChinaSun Yat‐sen University Cancer CenterCollaborative Innovation Center for Cancer Medicine Guangzhou China
| | - Zhixiao Han
- Department of AnesthesiologyGuangdong Provincial key Laboratory of Malignant Tumor Epigenetics and Gene Regulation. Sun Yat‐sen Memorial HospitalSun Yat‐sen University Guangzhou China
| | - Xiaodi Chen
- Department of AnesthesiologyState Key Laboratory of Oncology in Southern ChinaSun Yat‐sen University Cancer CenterCollaborative Innovation Center for Cancer Medicine Guangzhou China
| | - Xiaohui Bai
- Department of AnesthesiologyGuangdong Provincial key Laboratory of Malignant Tumor Epigenetics and Gene Regulation. Sun Yat‐sen Memorial HospitalSun Yat‐sen University Guangzhou China
| | - Handong Ouyang
- Department of AnesthesiologyState Key Laboratory of Oncology in Southern ChinaSun Yat‐sen University Cancer CenterCollaborative Innovation Center for Cancer Medicine Guangzhou China
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19
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Patwa S, Benson CA, Dyer L, Olson K, Bangalore L, Hill M, Waxman SG, Tan AM. Spinal cord motor neuron plasticity accompanies second-degree burn injury and chronic pain. Physiol Rep 2019; 7:e14288. [PMID: 31858746 PMCID: PMC6923170 DOI: 10.14814/phy2.14288] [Citation(s) in RCA: 10] [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] [Indexed: 12/31/2022] Open
Abstract
Burn injuries and associated complications present a major public health challenge. Many burn patients develop clinically intractable complications, including pain and other sensory disorders. Recent evidence has shown that dendritic spine neuropathology in spinal cord sensory and motor neurons accompanies central nervous system (CNS) or peripheral nervous system (PNS) trauma and disease. However, no research has investigated similar dendritic spine neuropathologies following a cutaneous thermal burn injury. In this retrospective investigation, we analyzed dendritic spine morphology and localization in alpha-motor neurons innervating a burn-injured area of the body (hind paw). To identify a molecular regulator of these dendritic spine changes, we further profiled motor neuron dendritic spines in adult mice treated with romidepsin, a clinically approved Pak1-inhibitor, or vehicle control at two postburn time points: Day 6 immediately after treatment, or Day 10 following drug withdrawal. In control treated mice, we observed an overall increase in dendritic spine density, including structurally mature spines with mushroom-shaped morphology. Pak1-inhibitor treatment reduced injury-induced changes to similar levels observed in animals without burn injury. The effectiveness of the Pak1-inhibitor was durable, since normalized dendritic spine profiles remained as long as 4 days despite drug withdrawal. This study is the first report of evidence demonstrating that a second-degree burn injury significantly affects motor neuron structure within the spinal cord. Furthermore, our results support the opportunity to study dendritic spine dysgenesis as a novel avenue to clarify the complexities of neurological disease following traumatic injury.
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Affiliation(s)
- Siraj Patwa
- Department of Neurology and Center for Neuroscience and Regeneration ResearchYale University School of MedicineNew HavenConnecticut
- Rehabilitation Research CenterVeterans Affairs Connecticut Healthcare SystemWest HavenConnecticut
| | - Curtis A. Benson
- Department of Neurology and Center for Neuroscience and Regeneration ResearchYale University School of MedicineNew HavenConnecticut
- Rehabilitation Research CenterVeterans Affairs Connecticut Healthcare SystemWest HavenConnecticut
| | - Lauren Dyer
- Department of Neurology and Center for Neuroscience and Regeneration ResearchYale University School of MedicineNew HavenConnecticut
- Rehabilitation Research CenterVeterans Affairs Connecticut Healthcare SystemWest HavenConnecticut
| | - Kai‐Lan Olson
- Department of Neurology and Center for Neuroscience and Regeneration ResearchYale University School of MedicineNew HavenConnecticut
- Rehabilitation Research CenterVeterans Affairs Connecticut Healthcare SystemWest HavenConnecticut
| | - Lakshmi Bangalore
- Department of Neurology and Center for Neuroscience and Regeneration ResearchYale University School of MedicineNew HavenConnecticut
- Rehabilitation Research CenterVeterans Affairs Connecticut Healthcare SystemWest HavenConnecticut
| | - Myriam Hill
- Department of Neurology and Center for Neuroscience and Regeneration ResearchYale University School of MedicineNew HavenConnecticut
- Rehabilitation Research CenterVeterans Affairs Connecticut Healthcare SystemWest HavenConnecticut
| | - Stephen G. Waxman
- Department of Neurology and Center for Neuroscience and Regeneration ResearchYale University School of MedicineNew HavenConnecticut
- Rehabilitation Research CenterVeterans Affairs Connecticut Healthcare SystemWest HavenConnecticut
| | - Andrew M. Tan
- Department of Neurology and Center for Neuroscience and Regeneration ResearchYale University School of MedicineNew HavenConnecticut
- Rehabilitation Research CenterVeterans Affairs Connecticut Healthcare SystemWest HavenConnecticut
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20
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Batista CM, Mariano ED, Onuchic F, Dale CS, dos Santos GB, Cristante AF, Otoch JP, Teixeira MJ, Morgalla M, Lepski G. Characterization of traumatic spinal cord injury model in relation to neuropathic pain in the rat. Somatosens Mot Res 2019; 36:14-23. [DOI: 10.1080/08990220.2018.1563537] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Chary Marquez Batista
- Department of Neurology, School of Medicine, Universidade de São Paulo, São Paulo, Brazil
| | - Eric Domingos Mariano
- Department of Neurology, School of Medicine, Universidade de São Paulo, São Paulo, Brazil
| | - Fernando Onuchic
- Department of Neurology, School of Medicine, Universidade de São Paulo, São Paulo, Brazil
| | | | - Gustavo Bispo dos Santos
- Department of Orthopedic and Traumatology, School of Medicine, Universidade de São Paulo, São Paulo, Brazil
| | - Alexandre Fogaça Cristante
- Department of Orthopedic and Traumatology, School of Medicine, Universidade de São Paulo, São Paulo, Brazil
| | - Jose Pinhata Otoch
- Department of Surgery, School of Medicine, Universidade de São Paulo, São Paulo, Brazil
| | | | - Matthias Morgalla
- Department of Neurosurgery, Eberhard-Karls University, Tuebingen, Germany
| | - Guilherme Lepski
- Department of Neurosurgery, Eberhard-Karls University, Tuebingen, Germany
- Department of Psychiatry, School of Medicine, University de São Paulo, São Paulo, Brazil
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21
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Batista CM, Mariano ED, Dale CS, Cristante AF, Britto LR, Otoch JP, Teixeira MJ, Morgalla M, Lepski G. Pain inhibition through transplantation of fetal neuronal progenitors into the injured spinal cord in rats. Neural Regen Res 2019; 14:2011-2019. [PMID: 31290460 PMCID: PMC6676883 DOI: 10.4103/1673-5374.259624] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Neuropathic pain after spinal cord injury (SCI) is a complex condition that responds poorly to usual treatments. Cell transplantation represents a promising therapy; nevertheless, the ideal cell type in terms of neurogenic potential and effectiveness against pain remains largely controversial. Here, we evaluated the ability of fetal neural stem cells (fNSC) to relieve chronic pain and, secondarily, their effects on motor recovery. Adult Wistar rats with traumatic SCI were treated, 10 days after injury, with intra-spinal injections of culture medium (sham) or fNSCs extracted from telencephalic vesicles (TV group) or the ventral medulla (VM group) of E/14 embryos. Sensory (von Frey filaments and hot plate) and motor (the Basso, Beattie, Bresnahan locomotor rating scale and inclined plane test) assessments were performed during 8 weeks. Thereafter, spinal cords were processed for immunofluorescence and transplanted cells were quantified by stereology. The results showed improvement of thermal hyperalgesia in the TV and VM groups at 4 and 5 weeks after transplantation, respectively. Moreover, mechanical allodynia improved in both the TV and VM groups at 8 weeks. No significant motor recovery was observed in the TV or VM groups compared with sham. Stereological analyses showed that ~70% of TV and VM cells differentiated into NeuN+ neurons, with a high proportion of enkephalinergic and GABAergic cells in the TV group and enkephalinergic and serotoninergic cells in the VM group. Our study suggests that neuronal precursors from TV and VM, once implanted into the injured spinal cord, maturate into different neuronal subtypes, mainly GABAergic, serotoninergic, and enkephalinergic, and all subtypes alleviate pain, despite no significant motor recovery. The study was approved by the Animal Ethics Committee of the Medical School of the University of São Paulo (protocol number 033/14) on March 4, 2016.
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Affiliation(s)
- Chary M Batista
- Department of Neurology, School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Eric D Mariano
- Department of Neurology, School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Camila S Dale
- Department of Anatomy, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
| | - Alexandre F Cristante
- Department of Orthopedic and Traumatology, School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Luiz R Britto
- Department of Physiology and Biophysics, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
| | - Jose P Otoch
- Department of Surgery, School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Manoel J Teixeira
- Department of Neurology, School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Matthias Morgalla
- Department of Neurosurgery, Eberhard-Karls University, Tuebingen, Germany
| | - Guilherme Lepski
- Department of Neurosurgery, Eberhard-Karls University, Tuebingen, Germany; Department of Psychiatry, School of Medicine, University of São Paulo, São Paulo, Brazil
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22
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Botulinum Toxin for Central Neuropathic Pain. Toxins (Basel) 2018; 10:toxins10060224. [PMID: 29857568 PMCID: PMC6024683 DOI: 10.3390/toxins10060224] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 05/26/2018] [Accepted: 05/28/2018] [Indexed: 11/17/2022] Open
Abstract
Botulinum toxin (BTX) is widely used to treat muscle spasticity by acting on motor neurons. Recently, studies of the effects of BTX on sensory nerves have been reported and several studies have been conducted to evaluate its effects on peripheral and central neuropathic pain. Central neuropathic pain includes spinal cord injury-related neuropathic pain, post-stroke shoulder pain, multiple sclerosis-related pain, and complex regional pain syndrome. This article reviews the mechanism of central neuropathic pain and assesses the effect of BTX on central neuropathic pain.
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Guo Y, Benson C, Hill M, Henry S, Effraim P, Waxman SG, Dib-Hajj S, Tan AM. Therapeutic potential of Pak1 inhibition for pain associated with cutaneous burn injury. Mol Pain 2018; 14:1744806918788648. [PMID: 29956587 PMCID: PMC6053256 DOI: 10.1177/1744806918788648] [Citation(s) in RCA: 12] [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: 04/18/2018] [Revised: 06/01/2018] [Accepted: 06/08/2018] [Indexed: 01/20/2023] Open
Abstract
Painful burn injuries are among the most debilitating form of trauma, globally ranking in the top 15 leading causes of chronic disease burden. Despite its prevalence, however, chronic pain after burn injury is under-studied. We previously demonstrated the contribution of the Rac1-signaling pathway in several models of neuropathic pain, including burn injury. However, Rac1 belongs to a class of GTPases with low therapeutic utility due to their complex intracellular dynamics. To further understand the mechanistic underpinnings of burn-induced neuropathic pain, we performed a longitudinal study to address the hypothesis that inhibition of the downstream effector of Rac1, Pak1, will improve pain outcome following a second-degree burn injury. Substantial evidence has identified Pak1 as promising a clinical target in cognitive dysfunction and is required for dendritic spine dysgenesis associated with many neurological diseases. In our burn injury model, mice exhibited significant tactile allodynia and heat hyperalgesia and dendritic spine dysgenesis in the dorsal horn. Activity-dependent expression of c-fos also increased in dorsal horn neurons, an indicator of elevated central nociceptive activity. To inhibit Pak1, we repurposed an FDA-approved inhibitor, romidepsin. Treatment with romidepsin decreased dendritic spine dysgenesis, reduced c-fos expression, and rescued pain thresholds. Drug discontinuation resulted in a relapse of cellular correlates of pain and in lower pain thresholds in behavioral tests. Taken together, our findings identify Pak1 signaling as a potential molecular target for therapeutic intervention in traumatic burn-induced neuropathic pain.
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Affiliation(s)
- Yiqun Guo
- Department of Neurology, Center for Neuroscience and
Regeneration Research,
Yale
University School of Medicine, New
Haven, CT, USA
- Rehabilitation Research Center, Veterans Affairs Connecticut
Healthcare System, West Haven, CT, USA
| | - Curtis Benson
- Department of Neurology, Center for Neuroscience and
Regeneration Research,
Yale
University School of Medicine, New
Haven, CT, USA
- Rehabilitation Research Center, Veterans Affairs Connecticut
Healthcare System, West Haven, CT, USA
| | - Myriam Hill
- Department of Neurology, Center for Neuroscience and
Regeneration Research,
Yale
University School of Medicine, New
Haven, CT, USA
- Rehabilitation Research Center, Veterans Affairs Connecticut
Healthcare System, West Haven, CT, USA
| | - Stefanie Henry
- Department of Neurology, Center for Neuroscience and
Regeneration Research,
Yale
University School of Medicine, New
Haven, CT, USA
- Rehabilitation Research Center, Veterans Affairs Connecticut
Healthcare System, West Haven, CT, USA
| | - Philip Effraim
- Department of Neurology, Center for Neuroscience and
Regeneration Research,
Yale
University School of Medicine, New
Haven, CT, USA
- Rehabilitation Research Center, Veterans Affairs Connecticut
Healthcare System, West Haven, CT, USA
| | - Stephen G Waxman
- Department of Neurology, Center for Neuroscience and
Regeneration Research,
Yale
University School of Medicine, New
Haven, CT, USA
- Rehabilitation Research Center, Veterans Affairs Connecticut
Healthcare System, West Haven, CT, USA
| | - Sulayman Dib-Hajj
- Department of Neurology, Center for Neuroscience and
Regeneration Research,
Yale
University School of Medicine, New
Haven, CT, USA
- Rehabilitation Research Center, Veterans Affairs Connecticut
Healthcare System, West Haven, CT, USA
| | - Andrew M Tan
- Department of Neurology, Center for Neuroscience and
Regeneration Research,
Yale
University School of Medicine, New
Haven, CT, USA
- Rehabilitation Research Center, Veterans Affairs Connecticut
Healthcare System, West Haven, CT, USA
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24
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Cao XC, Pappalardo LW, Waxman SG, Tan AM. Dendritic spine dysgenesis in superficial dorsal horn sensory neurons after spinal cord injury. Mol Pain 2017; 13:1744806916688016. [PMID: 28326929 PMCID: PMC5302173 DOI: 10.1177/1744806916688016] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Neuropathic pain is a major complication of spinal cord injury, and despite aggressive efforts, this type of pain is refractory to available clinical treatment. Our previous work has demonstrated a structure–function link between dendritic spine dysgenesis on nociceptive sensory neurons in the intermediate zone, laminae IV/V, and chronic pain in central nervous system and peripheral nervous system injury models of neuropathic pain. To extend these findings, we performed a follow-up structural analysis to assess whether dendritic spine remodeling occurs on superficial dorsal horn neurons located in lamina II after spinal cord injury. Lamina II neurons are responsible for relaying deep, delocalized, often thermally associated pain commonly experienced in spinal cord injury pathologies. We analyzed dendritic spine morphometry and localization in tissue obtained from adult rats exhibiting neuropathic pain one-month following spinal cord injury. Although the total density of dendritic spines on lamina II neurons did not change after spinal cord injury, we observed an inverse relationship between the densities of thin- and mushroom-shaped spines: thin-spine density decreased while mushroom-spine density increased. These structural changes were specifically noted along dendritic branches within 150 µm from the soma, suggesting a possible adverse contribution to nociceptive circuit function. Intrathecal treatment with NSC23766, a Rac1-GTPase inhibitor, significantly reduced spinal cord injury-induced changes in both thin- and mushroom-shaped dendritic spines. Overall, these observations demonstrate that dendritic spine remodeling occurs in lamina II, regulated in part by the Rac1-signaling pathway, and suggests that structural abnormalities in this spinal cord region may also contribute to abnormal nociception after spinal cord injury.
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Affiliation(s)
- Xiaoyu C Cao
- 1 Department of Neurology, Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT, USA.,2 Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA
| | - Laura W Pappalardo
- 1 Department of Neurology, Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT, USA.,2 Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA
| | - Stephen G Waxman
- 1 Department of Neurology, Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT, USA.,2 Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA
| | - Andrew M Tan
- 1 Department of Neurology, Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT, USA.,2 Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA
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25
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Neuronal-Glial Interactions Maintain Chronic Neuropathic Pain after Spinal Cord Injury. Neural Plast 2017; 2017:2480689. [PMID: 28951789 PMCID: PMC5603132 DOI: 10.1155/2017/2480689] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 06/26/2017] [Accepted: 07/05/2017] [Indexed: 02/01/2023] Open
Abstract
The hyperactive state of sensory neurons in the spinal cord enhances pain transmission. Spinal glial cells have also been implicated in enhanced excitability of spinal dorsal horn neurons, resulting in pain amplification and distortions. Traumatic injuries of the neural system such as spinal cord injury (SCI) induce neuronal hyperactivity and glial activation, causing maladaptive synaptic plasticity in the spinal cord. Recent studies demonstrate that SCI causes persistent glial activation with concomitant neuronal hyperactivity, thus providing the substrate for central neuropathic pain. Hyperactive sensory neurons and activated glial cells increase intracellular and extracellular glutamate, neuropeptides, adenosine triphosphates, proinflammatory cytokines, and reactive oxygen species concentrations, all of which enhance pain transmission. In addition, hyperactive sensory neurons and glial cells overexpress receptors and ion channels that maintain this enhanced pain transmission. Therefore, post-SCI neuronal-glial interactions create maladaptive synaptic circuits and activate intracellular signaling events that permanently contribute to enhanced neuropathic pain. In this review, we describe how hyperactivity of sensory neurons contributes to the maintenance of chronic neuropathic pain via neuronal-glial interactions following SCI.
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26
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Haefeli J, Huie JR, Morioka K, Ferguson AR. Assessments of sensory plasticity after spinal cord injury across species. Neurosci Lett 2017; 652:74-81. [PMID: 28007646 PMCID: PMC5466896 DOI: 10.1016/j.neulet.2016.12.031] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 12/08/2016] [Accepted: 12/14/2016] [Indexed: 12/26/2022]
Abstract
Spinal cord injury (SCI) is a multifaceted phenomenon associated with alterations in both motor function and sensory function. A majority of patients with SCI report sensory disturbances, including not only loss of sensation, but in many cases enhanced abnormal sensation, dysesthesia and pain. Development of therapeutics to treat these abnormal sensory changes require common measurement tools that can enable cross-species translation from animal models to human patients. We review the current literature on translational nociception/pain measurement in SCI and discuss areas for further development. Although a number of tools exist for measuring both segmental and affective sensory changes, we conclude that there is a pressing need for better, integrative measurement of nociception/pain outcomes across species to enhance precise therapeutic innovation for sensory dysfunction in SCI.
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Affiliation(s)
- Jenny Haefeli
- Weill Institute for Neurosciences, Brain and Spinal Injury Center (BASIC), Department of Neurological Surgery, University of California, San Francisco, CA, USA.
| | - J Russell Huie
- Weill Institute for Neurosciences, Brain and Spinal Injury Center (BASIC), Department of Neurological Surgery, University of California, San Francisco, CA, USA.
| | - Kazuhito Morioka
- Weill Institute for Neurosciences, Brain and Spinal Injury Center (BASIC), Department of Neurological Surgery, University of California, San Francisco, CA, USA.
| | - Adam R Ferguson
- Weill Institute for Neurosciences, Brain and Spinal Injury Center (BASIC), Department of Neurological Surgery, University of California, San Francisco, CA, USA; San Francisco Veteran's Affairs Medical Center, San Francisco, CA, USA.
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27
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Kramer JLK, Minhas NK, Jutzeler CR, Erskine ELKS, Liu LJW, Ramer MS. Neuropathic pain following traumatic spinal cord injury: Models, measurement, and mechanisms. J Neurosci Res 2016; 95:1295-1306. [PMID: 27617844 DOI: 10.1002/jnr.23881] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 07/19/2016] [Accepted: 07/19/2016] [Indexed: 02/06/2023]
Abstract
Neuropathic pain following spinal cord injury (SCI) is notoriously difficult to treat and is a high priority for many in the SCI population. Resolving this issue requires animal models fidelic to the clinical situation in terms of injury mechanism and pain phenotype. This Review discusses the means by which neuropathic pain has been induced and measured in experimental SCI and compares these with human outcomes, showing that there is a substantial disconnection between experimental investigations and clinical findings in a number of features. Clinical injury level is predominantly cervical, whereas injury in the laboratory is modeled mainly at the thoracic cord. Neuropathic pain is primarily spontaneous or tonic in people with SCI (with a relatively smaller incidence of allodynia), but measures of evoked responses (to thermal and mechanical stimuli) are almost exclusively used in animals. There is even the question of whether pain per se has been under investigation in most experimental SCI studies rather than simply enhanced reflex activity with no affective component. This Review also summarizes some of the problems related to clinical assessment of neuropathic pain and how advanced imaging techniques may circumvent a lack of patient/clinician objectivity and discusses possible etiologies of neuropathic pain following SCI based on evidence from both clinical studies and animal models, with examples of cellular and molecular changes drawn from the entire neuraxis from primary afferent terminals to cortical sensory and affective centers. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- John L K Kramer
- International Collaboration on Repair Discoveries, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Nikita K Minhas
- International Collaboration on Repair Discoveries, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Catherine R Jutzeler
- International Collaboration on Repair Discoveries, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Erin L K S Erskine
- International Collaboration on Repair Discoveries, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Lisa J W Liu
- International Collaboration on Repair Discoveries, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Matt S Ramer
- International Collaboration on Repair Discoveries, The University of British Columbia, Vancouver, British Columbia, Canada
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