1
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Xu X, Chen R, Yu Y, Yang J, Lin C, Liu R. Pulsed radiofrequency on DRG inhibits hippocampal neuroinflammation by regulating spinal GRK2/p38 expression and enhances spinal autophagy to reduce pain and depression in male rats with spared nerve injury. Int Immunopharmacol 2024; 127:111419. [PMID: 38141406 DOI: 10.1016/j.intimp.2023.111419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Revised: 12/17/2023] [Accepted: 12/17/2023] [Indexed: 12/25/2023]
Abstract
Evidence indicates that microglial G protein-coupled receptor kinase 2 (GRK2) is a key regulator of the transition from acute to chronic pain mediated by microglial products via the p38 mitogen-activated protein kinase (MAPK) pathway in the spinal cord dorsal horn (SCDH). Increasing studies have shown that autophagic dysfunction in the SCDH and neuroinflammation in the hippocampus underlie NeP. However, whether GRK2/p38MAPK and autophagic flux in the SCDH and hippocampal neuroinflammation are involved in NeP and depression comorbidity has not been determined. Here, we explored the effects of high-voltage pulsed radiofrequency (PRF) (85 V-PRF; HV-PRF) to the dorsal root ganglion (DRG) on pain phenotypes in Wistar male rats with spared nerve injury (SNI) and the underlying mechanisms. The exacerbation of pain phenotypes was markedly relieved by PRF-DRG. The SNI-induced reduction in GRK2 expression, elevation of p-p38 MAPK levels in the SCDH, and increase in IL-1β and TNF-α levels in the hippocampus were reversed by PRF, which was accompanied by an increase in autophagic flux in spinal microglia. The beneficial effect of 85 V-PRF was superior to that of 45 V-PRF. In addition, the improvements elicited by 85 V-PRF were reversed by intrathecal injection of GRK2 antisense oligonucleotide, and these changes were accompanied by GRK2 downregulation and p-p38 upregulation in the SCDH, increased pro-inflammatory factor levels in the hippocampus, and excessive autophagy in spinal microglia. In conclusion, our data indicate that the application of HV-PRF to the DRG could serve as an excellent therapeutic technique for regulating neuroimmunity and neuroinflammation to relieve pain phenotypes.
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Affiliation(s)
- Xueru Xu
- Department of Pain Management, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou City, Fujian Province, China
| | - Ri Chen
- Department of Pain Management, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou City, Fujian Province, China
| | - Youfen Yu
- Department of Pain Management, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou City, Fujian Province, China
| | - Jing Yang
- Department of Pain Management, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou City, Fujian Province, China
| | - Chun Lin
- Institute of Pain Research, School of Basic Medical Sciences, Fujian Medical University, Fuzhou City, Fujian Province, China
| | - Rongguo Liu
- Department of Pain Management, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou City, Fujian Province, China.
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2
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Golmakani H, Azimian A, Golmakani E. Newly discovered functions of miRNAs in neuropathic pain: Transitioning from recent discoveries to innovative underlying mechanisms. Mol Pain 2024; 20:17448069231225845. [PMID: 38148597 PMCID: PMC10851769 DOI: 10.1177/17448069231225845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 09/12/2023] [Accepted: 10/11/2023] [Indexed: 12/28/2023] Open
Abstract
Neuropathic pain is a widespread clinical issue caused by somatosensory nervous system damage, affecting numerous individuals. It poses considerable economic and public health challenges, and managing it can be challenging due to unclear underlying mechanisms. Nevertheless, emerging evidence suggests that neurogenic inflammation and neuroinflammation play a role in developing pain patterns. Emerging evidence suggests that neurogenic inflammation and neuroinflammation play significant roles in developing neuropathic pain within the nervous system. Increased/decreased miRNA expression patterns could affect the progression of neuropathic and inflammatory pain by controlling nerve regeneration, neuroinflammation, and the expression of abnormal ion channels. However, our limited knowledge of miRNA targets hinders a complete grasp of miRNA's functions. Meanwhile, exploring exosomal miRNA, a recently uncovered role, has significantly advanced our comprehension of neuropathic pain's pathophysiology in recent times. In this review, we present a comprehensive overview of the latest miRNA studies and explore the possible ways miRNAs might play a role in the development of neuropathic pain.
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Affiliation(s)
- Hasan Golmakani
- Department of Pediatrics, Faculty of Medicine, Mashhad Azad University, Mashhad, Iran
| | - Amir Azimian
- Department of Pathobiology and Laboratory Sciences, Faculty of Medicine, North Khorasan University of Medical Sciences, Bojnurd, Iran
| | - Ebrahim Golmakani
- Department of Anesthesiology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
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3
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Liu H, Lauzadis J, Gunaratna K, Sipple E, Kaczocha M, Puopolo M. Inhibition of T-Type Calcium Channels With TTA-P2 Reduces Chronic Neuropathic Pain Following Spinal Cord Injury in Rats. THE JOURNAL OF PAIN 2023; 24:1681-1695. [PMID: 37169156 DOI: 10.1016/j.jpain.2023.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 04/03/2023] [Accepted: 05/02/2023] [Indexed: 05/13/2023]
Abstract
Spinal cord injury (SCI)-induced neuropathic pain (SCI-NP) develops in up to 60 to 70% of people affected by traumatic SCI, leading to a major decline in quality of life and increased risk for depression, anxiety, and addiction. Gabapentin and pregabalin, together with antidepressant drugs, are commonly prescribed to treat SCI-NP, but their efficacy is unsatisfactory. The limited efficacy of current pharmacological treatments for SCI-NP likely reflects our limited knowledge of the underlying mechanism(s) responsible for driving the maintenance of SCI-NP. The leading hypothesis in the field supports a major role for spontaneously active injured nociceptors in driving the maintenance of SCI-NP. Recent data from our laboratory provided additional support for this hypothesis and identified the T-type calcium channels as key players in driving the spontaneous activity of SCI-nociceptors, thus providing a rational pharmacological target to treat SCI-NP. To test whether T-type calcium channels contribute to the maintenance of SCI-NP, male and female SCI and sham rats were treated with TTA-P2 (a blocker of T-type calcium channels) to determine its effects on mechanical hypersensitivity (as measured with the von Frey filaments) and spontaneous ongoing pain (as measured with the conditioned place preference paradigm), and compared them to the effects of gabapentin, a blocker of high voltage-activated calcium channels. We found that both TTA-P2 and gabapentin reduced mechanical hypersensitivity in male and females SCI rats, but surprisingly only TTA-P2 reduced spontaneous ongoing pain in male SCI rats. PERSPECTIVES: SCI-induced neuropathic pain, and in particular the spontaneous ongoing pain component, is notoriously very difficult to treat. Our data provide evidence that inhibition of T-type calcium channels reduces spontaneous ongoing pain in SCI rats, supporting a clinically relevant role for T-type channels in the maintenance of SCI-induced neuropathic pain.
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Affiliation(s)
- Huilin Liu
- Department of Anesthesiology, Stony Brook Pain and Analgesia Research Center (SPARC), Health Sciences Center L4-072, Stony Brook Renaissance School of Medicine, Stony Brook, New York
| | - Justas Lauzadis
- Department of Anesthesiology, Stony Brook Pain and Analgesia Research Center (SPARC), Health Sciences Center L4-072, Stony Brook Renaissance School of Medicine, Stony Brook, New York
| | - Kavindu Gunaratna
- Department of Anesthesiology, Stony Brook Pain and Analgesia Research Center (SPARC), Health Sciences Center L4-072, Stony Brook Renaissance School of Medicine, Stony Brook, New York
| | - Erin Sipple
- Department of Anesthesiology, Stony Brook Pain and Analgesia Research Center (SPARC), Health Sciences Center L4-072, Stony Brook Renaissance School of Medicine, Stony Brook, New York
| | - Martin Kaczocha
- Department of Anesthesiology, Stony Brook Pain and Analgesia Research Center (SPARC), Health Sciences Center L4-072, Stony Brook Renaissance School of Medicine, Stony Brook, New York
| | - Michelino Puopolo
- Department of Anesthesiology, Stony Brook Pain and Analgesia Research Center (SPARC), Health Sciences Center L4-072, Stony Brook Renaissance School of Medicine, Stony Brook, New York.
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4
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Di Cesare F, Negro V, Ravasio G, Villa R, Draghi S, Cagnardi P. Gabapentin: Clinical Use and Pharmacokinetics in Dogs, Cats, and Horses. Animals (Basel) 2023; 13:2045. [PMID: 37370556 DOI: 10.3390/ani13122045] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 06/16/2023] [Accepted: 06/19/2023] [Indexed: 06/29/2023] Open
Abstract
Gabapentin is an anticonvulsant drug, which presents an established clinical efficacy in human patients for the management of refractory partial seizures, secondarily generalized tonic-clonic seizures, and for the control of chronic neuropathic pain. Gabapentin was synthesized as a structural analogue of the inhibitory neurotransmitter GABA, with GABA-mimetic effects, able to cross the blood-brain barrier. In veterinary medicine, is extra-label used in combination with other treatments to control seizures when other drugs are no longer effective or become toxic or for neuropathic pain treatment and anxiety. This review aimed to clarify gabapentin use and pharmacokinetic aspects to promote conscious use in dogs, cats, and horses. In dogs, gabapentin was beneficial in the treatment of epilepsy, as well as chronic, neuropathic, and post-operative pain, as well as anxiety. In cats, it showed efficacy in post-ovariohysterectomy-related pain and in anxiety management. In horses, gabapentin has been administered as an analgesic for chronic pain management. In conclusion, when used in combination with other drugs, gabapentin can be considered an interesting therapeutic option for the treatment of neuropathic diseases and analgesia in postoperative and chronic pain. However, despite its beneficial use in different clinical settings, further trials and pharmacokinetic studies are needed for the definition of an effective dosage regimen through proper pharmacokinetic/pharmacodynamic correlation in dogs, cats, and horses.
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Affiliation(s)
- Federica Di Cesare
- Department of Veterinary Medicine and Animal Sciences, Università degli Studi di Milano, Via dell'Università 6, 26900 Lodi, Italy
| | - Viviana Negro
- Department of Veterinary Medicine and Animal Sciences, Università degli Studi di Milano, Via dell'Università 6, 26900 Lodi, Italy
| | - Giuliano Ravasio
- Department of Veterinary Medicine and Animal Sciences, Università degli Studi di Milano, Via dell'Università 6, 26900 Lodi, Italy
| | - Roberto Villa
- Department of Veterinary Medicine and Animal Sciences, Università degli Studi di Milano, Via dell'Università 6, 26900 Lodi, Italy
| | - Susanna Draghi
- Department of Veterinary Medicine and Animal Sciences, Università degli Studi di Milano, Via dell'Università 6, 26900 Lodi, Italy
| | - Petra Cagnardi
- Department of Veterinary Medicine and Animal Sciences, Università degli Studi di Milano, Via dell'Università 6, 26900 Lodi, Italy
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5
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Zhu J, Huang F, Hu Y, Qiao W, Guan Y, Zhang ZJ, Liu S, Liu Y. Non-Coding RNAs Regulate Spinal Cord Injury-Related Neuropathic Pain via Neuroinflammation. J Inflamm Res 2023; 16:2477-2489. [PMID: 37334347 PMCID: PMC10276590 DOI: 10.2147/jir.s413264] [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: 03/20/2023] [Accepted: 06/02/2023] [Indexed: 06/20/2023] Open
Abstract
Secondary chronic neuropathic pain (NP) in addition to sensory, motor, or autonomic dysfunction can significantly reduce quality of life after spinal cord injury (SCI). The mechanisms of SCI-related NP have been studied in clinical trials and with the use of experimental models. However, in developing new treatment strategies for SCI patients, NP poses new challenges. The inflammatory response following SCI promotes the development of NP. Previous studies suggest that reducing neuroinflammation following SCI can improve NP-related behaviors. Intensive studies of the roles of non-coding RNAs in SCI have discovered that ncRNAs bind target mRNA, act between activated glia, neuronal cells, or other immunocytes, regulate gene expression, inhibit inflammation, and influence the prognosis of NP.
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Affiliation(s)
- Jing Zhu
- Department of Rehabilitation Medicine, Affiliated Hospital of Nantong University, Medical School of Nantong University, Nantong, JiangSu Province, 226001, People’s Republic of China
| | - Fei Huang
- Department of Rehabilitation Medicine, Affiliated Hospital of Nantong University, Medical School of Nantong University, Nantong, JiangSu Province, 226001, People’s Republic of China
- Department of Rehabilitation Medicine, Nantong Health College of Jiangsu Province, Nantong, JiangSu Province, 226010, People’s Republic of China
| | - Yonglin Hu
- Department of Rehabilitation Medicine, Affiliated Hospital of Nantong University, Medical School of Nantong University, Nantong, JiangSu Province, 226001, People’s Republic of China
- Affiliated Nantong Rehabilitation Hospital of Nantong University, Nantong, JiangSu Province, 226001, People’s Republic of China
| | - Wei Qiao
- Department of Rehabilitation Medicine, Affiliated Hospital of Nantong University, Medical School of Nantong University, Nantong, JiangSu Province, 226001, People’s Republic of China
| | - Yingchao Guan
- Department of Rehabilitation Medicine, Affiliated Hospital of Nantong University, Medical School of Nantong University, Nantong, JiangSu Province, 226001, People’s Republic of China
| | - Zhi-Jun Zhang
- Department of Rehabilitation Medicine, Affiliated Hospital of Nantong University, Medical School of Nantong University, Nantong, JiangSu Province, 226001, People’s Republic of China
| | - Su Liu
- Department of Rehabilitation Medicine, Affiliated Hospital of Nantong University, Medical School of Nantong University, Nantong, JiangSu Province, 226001, People’s Republic of China
| | - Ying Liu
- Department of Pathology, Affiliated Hospital of Nantong University, Nantong, JiangSu Province, 226001, People’s Republic of China
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6
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Li Q, Li R, Zhu X, Chu X, An X, Chen M, Zhang L, Gao M, Chen L. EphA1 aggravates neuropathic pain by activating CXCR4/RhoA/ROCK2 pathway in mice. Hum Cell 2023:10.1007/s13577-023-00911-9. [PMID: 37162645 DOI: 10.1007/s13577-023-00911-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 04/23/2023] [Indexed: 05/11/2023]
Abstract
Neuropathic pain is a refractory disease with limited treatment options due to its complex mechanisms. Whereas erythropoietin-producing hepatocyte A1 (EphA1) mediates the production of inflammatory factors that are important in the progression of neurological diseases, its role and molecular mechanisms in neuropathic pain remain unclear. In the present study, we established a mouse model of chronic constriction injury (CCI). EphA1 expression was observed to be progressively upregulated at the mRNA and protein levels with the progression of the disease. Subsequently, knockdown of EphA1 expression levels using adenovirus short hairpin RNA (AAV-shEphA1) revealed an increase in mechanical stimulation withdrawal threshold (PWT) and withdrawal latency (PWL) when EphA1 expression was decreased, accompanied by improved dorsal root ganglion injury, increased leukocytosis, decreased microglia, and decreased levels of pro-inflammatory factors. For the underlying mechanism, it was found that EphA1 regulates the activity of the RhoA/ROCK2 pathway by modulating the level of CXCR4. Inhibition of CXCR4 and RhoA/ROCK2 could effectively alleviate the promoting effect of EphA1 upregulation on neuropathic pain. In conclusion, our study suggests that depletion of EphA1 ameliorates neuropathic pain by modulating the CXCR4/RhoA/ROCK2 signaling pathway, and targeting EphA1 may be a potential clinical treatment for neuropathic pain.
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Affiliation(s)
- Qi Li
- Department of Rehabilitation Medicine, Tianjin Hospital, Tianjin University, Tianjin, 300211, China
- Academy of Medical Engineering and Translational Medicine, Tianjin University, 92, Weijin Road, Nankai District, Tianjin, 300072, China
| | - Rui Li
- Traditional Chinese Medicine Department, Guizhou Provincial People's Hospital, Guiyang, 550002, Guizhou Province, China
| | - Xiaoxi Zhu
- Key Laboratory of Molecular Biology, Guizhou Medical University, Guiyang, 550004, Guizhou Province, China
| | - Xiaolei Chu
- Department of Rehabilitation Medicine, Tianjin Hospital, Tianjin University, Tianjin, 300211, China
| | - Xiaoqiong An
- School of Basic Medical Science, Guizhou Medical University, Guiyang, 550004, Guizhou Province, China
| | - Ming Chen
- School of Basic Medical Science, Guizhou Medical University, Guiyang, 550004, Guizhou Province, China
| | - Lei Zhang
- Academy of Medical Engineering and Translational Medicine, Tianjin University, 92, Weijin Road, Nankai District, Tianjin, 300072, China
| | - Mingwei Gao
- Academy of the Society of Sport and Health Sciences, Tianjin University of Sport, Tianjin, 301617, China
| | - Long Chen
- Academy of Medical Engineering and Translational Medicine, Tianjin University, 92, Weijin Road, Nankai District, Tianjin, 300072, China.
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7
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Cuevas-Diaz Duran R, Li Y, Garza Carbajal A, You Y, Dessauer CW, Wu J, Walters ET. Major Differences in Transcriptional Alterations in Dorsal Root Ganglia Between Spinal Cord Injury and Peripheral Neuropathic Pain Models. J Neurotrauma 2023; 40:883-900. [PMID: 36178348 PMCID: PMC10150729 DOI: 10.1089/neu.2022.0238] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Chronic, often intractable, pain is caused by neuropathic conditions such as traumatic peripheral nerve injury (PNI) and spinal cord injury (SCI). These conditions are associated with alterations in gene and protein expression correlated with functional changes in somatosensory neurons having cell bodies in dorsal root ganglia (DRGs). Most studies of DRG transcriptional alterations have utilized PNI models where axotomy-induced changes important for neural regeneration may overshadow changes that drive neuropathic pain. Both PNI and SCI produce DRG neuron hyperexcitability linked to pain, but contusive SCI produces little peripheral axotomy or peripheral nerve inflammation. Thus, comparison of transcriptional signatures of DRGs across PNI and SCI models may highlight pain-associated transcriptional alterations in sensory ganglia that do not depend on peripheral axotomy or associated effects such as peripheral Wallerian degeneration. Data from our rat thoracic SCI experiments were combined with meta-analysis of published whole-DRG RNA-seq datasets from prominent rat PNI models. Striking differences were found between transcriptional responses to PNI and SCI, especially in regeneration-associated genes (RAGs) and long noncoding RNAs (lncRNAs). Many transcriptomic changes after SCI also were found after corresponding sham surgery, indicating they were caused by injury to surrounding tissue, including bone and muscle, rather than to the spinal cord itself. Another unexpected finding was of few transcriptomic similarities between rat neuropathic pain models and the only reported transcriptional analysis of human DRGs linked to neuropathic pain. These findings show that DRGs exhibit complex transcriptional responses to central and peripheral neural injury and associated tissue damage. Although only a few genes in DRG cells exhibited similar changes in expression across all the painful conditions examined here, these genes may represent a core set whose transcription in various DRG cell types is sensitive to significant bodily injury, and which may play a fundamental role in promoting neuropathic pain.
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Affiliation(s)
- Raquel Cuevas-Diaz Duran
- Tecnologico de Monterrey, Escuela de Medicina y Ciencias de la Salud, Monterrey, Nuevo Leon, Mexico
| | - Yong Li
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Anibal Garza Carbajal
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Yanan You
- Department of Neurosurgery, The University of Texas Health Science Center at Houston, Houston, Texas, USA
- Center for Stem Cell and Regenerative Medicine, UT Brown Foundation Institute of Molecular Medicine, Houston, Texas, USA
| | - Carmen W. Dessauer
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Jiaqian Wu
- Department of Neurosurgery, The University of Texas Health Science Center at Houston, Houston, Texas, USA
- Center for Stem Cell and Regenerative Medicine, UT Brown Foundation Institute of Molecular Medicine, Houston, Texas, USA
| | - Edgar T. Walters
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, Texas, USA
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8
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Mastrorilli V, De Angelis F, Vacca V, Pavone F, Luvisetto S, Marinelli S. Xeomin®, a Commercial Formulation of Botulinum Neurotoxin Type A, Promotes Regeneration in a Preclinical Model of Spinal Cord Injury. Toxins (Basel) 2023; 15:toxins15040248. [PMID: 37104185 PMCID: PMC10142820 DOI: 10.3390/toxins15040248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 03/17/2023] [Accepted: 03/27/2023] [Indexed: 03/31/2023] Open
Abstract
Xeomin® is a commercial formulation of botulinum neurotoxin type A (BoNT/A) clinically authorized for treating neurological disorders, such as blepharospasm, cervical dystonia, limb spasticity, and sialorrhea. We have previously demonstrated that spinal injection of laboratory purified 150 kDa BoNT/A in paraplegic mice, after undergoing traumatic spinal cord injury (SCI), was able to reduce excitotoxic phenomena, glial scar, inflammation, and the development of neuropathic pain and facilitate regeneration and motor recovery. In the present study, as proof of concept in view of a possible clinical application, we studied the efficacy of Xeomin® in the same preclinical SCI model in which we highlighted the positive effects of lab-purified BoNT/A. Data comparison shows that Xeomin® induces similar pharmacological and therapeutic effects, albeit with less efficacy, to lab-purified BoNT/A. This difference, which can be improved by adjusting the dose, can be attributable to the different formulation and pharmacodynamics. Although the mechanism by which Xeomin® and laboratory purified BoNT/A induce functional improvement in paraplegic mice is still far from being understood, these results open a possible new scenario in treatment of SCI and are a stimulus for further research.
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9
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Ferreyra S, González S. Therapeutic potential of progesterone in spinal cord injury-induced neuropathic pain: At the crossroads between neuroinflammation and N-methyl-D-aspartate receptor. J Neuroendocrinol 2023; 35:e13181. [PMID: 35924434 DOI: 10.1111/jne.13181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 06/13/2022] [Accepted: 06/19/2022] [Indexed: 10/17/2022]
Abstract
In recent decades, an area of active research has supported the notion that progesterone promotes a wide range of remarkable protective actions in experimental models of nervous system trauma or disease, and has also provided a strong basis for considering this steroid as a promising molecule for modulating the complex maladaptive changes that lead to neuropathic pain, especially after spinal cord injury. In this review, we intend to give the readers a brief appraisal of the main mechanisms underlying the increased excitability of the spinal circuit in the pain pathway after trauma, with particular emphasis on those mediated by the activation of resident glial cells, the subsequent release of proinflammatory cytokines and their impact on N-methyl-D-aspartate receptor function. We then summarize the available preclinical data pointing to progesterone as a valuable repurposing molecule for blocking critical cellular and molecular events that occur in the dorsal horn of the injured spinal cord and are related to the development of chronic pain. Since the treatment and management of neuropathic pain after spinal injury remains challenging, the potential therapeutic value of progesterone opens new traslational perspectives to prevent central pain.
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Affiliation(s)
- Sol Ferreyra
- Instituto de Biología y Medicina Experimental, Laboratorio de Nocicepción y Dolor Neuropático, CONICET, Buenos Aires, Argentina
| | - Susana González
- Instituto de Biología y Medicina Experimental, Laboratorio de Nocicepción y Dolor Neuropático, CONICET, Buenos Aires, Argentina
- Universidad de Buenos Aires, Facultad de Medicina, Departamento de Bioquímica Humana, Buenos Aires, Argentina
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10
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Chen Y, Li D, Li N, Loh P, Guo Y, Hu X, Zhang J, Dou B, Wang L, Yang C, Guo T, Chen S, Liu Z, Chen B, Chen Z. Role of nerve signal transduction and neuroimmune crosstalk in mediating the analgesic effects of acupuncture for neuropathic pain. Front Neurol 2023; 14:1093849. [PMID: 36756246 PMCID: PMC9899820 DOI: 10.3389/fneur.2023.1093849] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 01/09/2023] [Indexed: 01/24/2023] Open
Abstract
Neurogenic pain rises because of nervous system damage or dysfunction and is the most difficult to treat among other pathological pains. Acupuncture has been reported as a great treatment option for neurogenic pain owing to its unlimited advantages. However, previous studies on the analgesic effects of acupuncture for NP were scattered and did not form a whole. In this study, we first comprehensively review the relevant basic articles on acupuncture for NP published in the last 5 years and summarize the analgesic mechanisms of acupuncture in terms of nerve signaling, neuro-immune crosstalk, and metabolic and oxidative stress regulation. Acupuncture inhibits the upstream excitatory system and suppresses neuronal transmission efficiency by downregulating glutamate, NMDA receptors, P2XR, SP, CGRP, and other neurotransmitters and receptors in the spinal cord, as well as plasma channels such as TRPV1, HCN. It can also activate the downstream pain inhibitory pathway by upregulating opioid peptide (β-endorphin), MOR receptors, GABA and GABA receptors, bi-directional regulating 5-hydroxytryptamine (5-HT) and its receptors (upregulate 5-HT 1A and downregulate 5-HT7R) and stimulating hypothalamic appetite-modifying neurons. Moreover, neuroinflammation in pain can be inhibited by acupuncture through inhibiting JAK2/STAT3, PI3K/mTOR pathways, down regulating chemokine receptor CX3CR1 on microglia and up regulating adenosine receptor A1Rs on astrocytes, inhibiting the activation of glia and reducing TNF-α and other inflammatory substances. Acupuncture also inhibits neuronal glucose metabolism by downregulating mPFC's GLUT-3 and promotes metabolic alterations of the brain, thus exerting an analgesic effect. In conclusion, the regulation of nerve signal transduction and neuroimmune crosstalk at the peripheral and central levels mediates the analgesic effects of acupuncture for neuropathic pain in an integrated manner. These findings provide a reliable basis for better clinical application of acupuncture in the management of neuropathic pain.
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Affiliation(s)
- Yong Chen
- Research Center of Experimental Acupuncture Science, Tianjin University of Traditional Chinese Medicine, Tianjin, China,School of Acupuncture & Moxibustion and Tuina, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Dan Li
- Research Center of Experimental Acupuncture Science, Tianjin University of Traditional Chinese Medicine, Tianjin, China,School of Acupuncture & Moxibustion and Tuina, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Ningcen Li
- Laboratory Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - PeiYong Loh
- School of International Education, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Yi Guo
- Research Center of Experimental Acupuncture Science, Tianjin University of Traditional Chinese Medicine, Tianjin, China,National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, China,School of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Xiyou Hu
- Research Center of Experimental Acupuncture Science, Tianjin University of Traditional Chinese Medicine, Tianjin, China,School of Acupuncture & Moxibustion and Tuina, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Jingyu Zhang
- Research Center of Experimental Acupuncture Science, Tianjin University of Traditional Chinese Medicine, Tianjin, China,School of Acupuncture & Moxibustion and Tuina, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Baomin Dou
- Research Center of Experimental Acupuncture Science, Tianjin University of Traditional Chinese Medicine, Tianjin, China,School of Acupuncture & Moxibustion and Tuina, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Lifen Wang
- Research Center of Experimental Acupuncture Science, Tianjin University of Traditional Chinese Medicine, Tianjin, China,School of Acupuncture & Moxibustion and Tuina, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Chaobo Yang
- Research Center of Experimental Acupuncture Science, Tianjin University of Traditional Chinese Medicine, Tianjin, China,School of Acupuncture & Moxibustion and Tuina, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Tao Guo
- Research Center of Experimental Acupuncture Science, Tianjin University of Traditional Chinese Medicine, Tianjin, China,School of Acupuncture & Moxibustion and Tuina, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Shuangli Chen
- Research Center of Experimental Acupuncture Science, Tianjin University of Traditional Chinese Medicine, Tianjin, China,School of Acupuncture & Moxibustion and Tuina, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Zhen Liu
- Research Center of Experimental Acupuncture Science, Tianjin University of Traditional Chinese Medicine, Tianjin, China,School of Acupuncture & Moxibustion and Tuina, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Bo Chen
- Research Center of Experimental Acupuncture Science, Tianjin University of Traditional Chinese Medicine, Tianjin, China,School of Acupuncture & Moxibustion and Tuina, Tianjin University of Traditional Chinese Medicine, Tianjin, China,National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, China,*Correspondence: Zelin Chen ✉
| | - Zelin Chen
- Research Center of Experimental Acupuncture Science, Tianjin University of Traditional Chinese Medicine, Tianjin, China,School of Acupuncture & Moxibustion and Tuina, Tianjin University of Traditional Chinese Medicine, Tianjin, China,National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, China,Bo Chen ✉
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11
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Furlan JC, Loh E, Boulos MI. The potential effects of untreated sleep-related breathing disorders on neuropathic pain, spasticity, and cardiovascular dysfunction following spinal cord injury: A cross-sectional prospective study protocol. PLoS One 2023; 18:e0282860. [PMID: 37130111 PMCID: PMC10153696 DOI: 10.1371/journal.pone.0282860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 02/13/2023] [Indexed: 05/03/2023] Open
Abstract
INTRODUCTION Sleep-related breathing disorders (SRBDs), neuropathic pain, spasticity and cardiovascular autonomic dysfunction are common after spinal cord injury (SCI). Prior studies suggest that systemic inflammation following SCI may be implicated in the development of neuropathic pain, spasticity and cardiovascular dysfunction. Given that SRBDs also cause a systemic inflammatory response, we hypothesized that individuals with SCI who develop more severe SRBDs would experience more intense neuropathic pain, more severe spasticity and more significant cardiovascular autonomic dysfunction. METHODS This cross-sectional prospective study will explore the previously understudied hypothesis that SRBDs are associated with increased neuropathic pain, spasticity, and cardiovascular autonomic dysfunction in adult individuals with low-cervical/high-thoracic (injury level at C5 to T6), complete/incomplete (ASIA Impairment Scale A, B, C or D) SCI. DISCUSSION To our knowledge, no prior study has addressed this clinically relevant question on whether the degree of SRBDs affects the intensity of neuropathic pain, spasticity, and cardiovascular autonomic dysfunction in individuals with SCI. We anticipate that the results of this original study will provide key information for a future clinical trial on the use of continuous positive airway pressure (CPAP) therapy for moderate-to-severe SRBDs, which may better control neuropathic pain, spasticity, and cardiovascular autonomic dysfunction among individuals with SCI. TRIAL REGISTRATION The research protocol for this study was registered in the ClinicalTrials.gov website (NCT05687097). https://clinicaltrials.gov/ct2/show/NCT05687097.
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Affiliation(s)
- Julio Cesar Furlan
- Toronto Rehabilitation Institute, Lyndhurst Centre, University Health Network, Toronto, Ontario, Canada
- KITE Research Institute, University Health Network, Toronto, Ontario, Canada
- Department of Medicine, Division of Physical Medicine and Rehabilitation, University of Toronto, Toronto, Ontario, Canada
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
- Rehabilitation Sciences Institute, University of Toronto, Toronto, Ontario, Canada
- Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, Ontario, Canada
| | - Eldon Loh
- Department of Physical Medicine and Rehabilitation, University of Western Ontario, London, ON, Canada
- Parkwood Institute Research, Lawson Health Research Institute, London, ON, Canada
| | - Mark Iskander Boulos
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
- Rehabilitation Sciences Institute, University of Toronto, Toronto, Ontario, Canada
- Sunnybrook Research Institute and Sunnybrook Health Sciences Centre, Hurvitz Brain Sciences Research Program, Toronto, ON, Canada
- Department of Medicine, Division of Neurology, University of Toronto, Toronto, ON, Canada
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12
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Zhao YY, Wu ZJ, Zhu LJ, Niu TX, Liu B, Li J. Emerging roles of miRNAs in neuropathic pain: From new findings to novel mechanisms. Front Mol Neurosci 2023; 16:1110975. [PMID: 36873108 PMCID: PMC9981676 DOI: 10.3389/fnmol.2023.1110975] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 01/30/2023] [Indexed: 02/19/2023] Open
Abstract
Neuropathic pain, which results from damage to the somatosensory nervous system, is a global clinical condition that affects many people. Neuropathic pain imposes significant economic and public health burdens and is often difficult to manage because the underlying mechanisms remain unclear. However, mounting evidence indicates a role for neurogenic inflammation and neuroinflammation in pain pattern development. There is increasing evidence that the activation of neurogenic inflammation and neuroinflammation in the nervous system contribute to neuropathic pain. Altered miRNA expression profiles might be involved in the pathogenesis of both inflammatory and neuropathic pain by regulating neuroinflammation, nerve regeneration, and abnormal ion channel expression. However, the lack of knowledge about miRNA target genes prevents a full understanding of the biological functions of miRNAs. At the same time, an extensive study on exosomal miRNA, a newly discovered role, has advanced our understanding of the pathophysiology of neuropathic pain in recent years. This section provides a comprehensive overview of the current understanding of miRNA research and discusses the potential mechanisms of miRNAs in neuropathic pain.
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Affiliation(s)
- Yu-Ying Zhao
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China.,Tianjin Research Institute of Anesthesiology, Tianjin, China
| | - Zi-Jun Wu
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China.,Tianjin Research Institute of Anesthesiology, Tianjin, China
| | - Li-Juan Zhu
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China.,Tianjin Research Institute of Anesthesiology, Tianjin, China
| | - Tong-Xiang Niu
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China.,Tianjin Research Institute of Anesthesiology, Tianjin, China
| | - Bin Liu
- Department of Critical Care Medicine, General Hospital of Tianjin Medical University, Tianjin, China.,Center for Critical Care Medicine, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Tianjin, China
| | - Jing Li
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China.,Tianjin Research Institute of Anesthesiology, Tianjin, China
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13
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Zheng S, Tian Y, Ouyang J, Shen Y, Wang X, Luan J. Carbon nanomaterials for drug delivery and tissue engineering. Front Chem 2022; 10:990362. [PMID: 36171994 PMCID: PMC9510755 DOI: 10.3389/fchem.2022.990362] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Accepted: 08/19/2022] [Indexed: 11/14/2022] Open
Abstract
Carbon nanomaterials are some of the state-of-the-art materials used in drug-delivery and tissue-engineering research. Compared with traditional materials, carbon nanomaterials have the advantages of large specific surface areas and unique properties and are more suitable for use in drug delivery and tissue engineering after modification. Their characteristics, such as high drug loading and tissue loading, good biocompatibility, good targeting and long duration of action, indicate their great development potential for biomedical applications. In this paper, the synthesis and application of carbon dots (CDs), carbon nanotubes (CNTs) and graphene in drug delivery and tissue engineering are reviewed in detail. In this review, we discuss the current research focus and existing problems of carbon nanomaterials in order to provide a reference for the safe and effective application of carbon nanomaterials in drug delivery and tissue engineering.
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Affiliation(s)
- Shaolie Zheng
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Yuan Tian
- Department of Chemistry, Jinan University, Guangzhou, China
| | - Jiang Ouyang
- Department of Chemistry, Jinan University, Guangzhou, China
| | - Yuan Shen
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Xiaoyu Wang
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of Jinan University, Guangzhou, China
- *Correspondence: Xiaoyu Wang, ; Jian Luan,
| | - Jian Luan
- College of Sciences, Northeastern University, Shenyang, China
- *Correspondence: Xiaoyu Wang, ; Jian Luan,
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14
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Karri J, Doan J, Vangeison C, Catalanotto M, Nagpal AS, Li S. Emerging Evidence for Intrathecal Management of Neuropathic Pain Following Spinal Cord Injury. FRONTIERS IN PAIN RESEARCH 2022; 3:933422. [PMID: 35965596 PMCID: PMC9371595 DOI: 10.3389/fpain.2022.933422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 06/14/2022] [Indexed: 11/13/2022] Open
Abstract
A high prevalence of patients with spinal cord injury (SCI) suffer from chronic neuropathic pain. Unfortunately, the precise pathophysiological mechanisms underlying this phenomenon have yet to be clearly elucidated and targeted treatments are largely lacking. As an unfortunate consequence, neuropathic pain in the population with SCI is refractory to standard of care treatments and represents a significant contributor to morbidity and suffering. In recent years, advances from SCI-specific animal studies and translational models have furthered our understanding of the neuronal excitability, glial dysregulation, and chronic inflammation processes that facilitate neuropathic pain. These developments have served advantageously to facilitate exploration into the use of neuromodulation as a treatment modality. The use of intrathecal drug delivery (IDD), with novel pharmacotherapies, to treat chronic neuropathic pain has gained particular attention in both pre-clinical and clinical contexts. In this evidence-based narrative review, we provide a comprehensive exploration into the emerging evidence for the pathogenesis of neuropathic pain following SCI, the evidence basis for IDD as a therapeutic strategy, and novel pharmacologics across impactful animal and clinical studies.
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Affiliation(s)
- Jay Karri
- Division of Pain Medicine, Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- *Correspondence: Jay Karri
| | - James Doan
- Department of Physical Medicine and Rehabilitation, Harvard Medical School, Boston, MA, United States
- Veterans Affairs Boston Healthcare System—West Roxbury Division, Spinal Cord Injury Service, Boston, MA, United States
| | - Christian Vangeison
- Department of Physical Medicine and Rehabilitation, Baylor College of Medicine, Houston, TX, United States
| | - Marissa Catalanotto
- Department of Physical Medicine and Rehabilitation, Baylor College of Medicine, Houston, TX, United States
| | - Ameet S. Nagpal
- Department of Orthopaedics and Physical Medicine, Medical University of South Carolina, Charleston, SC, United States
| | - Sheng Li
- Department of Physical Medicine and Rehabilitation, McGovern Medical School, University of Texas HSC at Houston, Houston, TX, United States
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15
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Massimini M, Bachetti B, Dalle Vedove E, Benvenga A, Di Pierro F, Bernabò N. A Set of Dysregulated Target Genes to Reduce Neuroinflammation at Molecular Level. Int J Mol Sci 2022; 23:ijms23137175. [PMID: 35806178 PMCID: PMC9266409 DOI: 10.3390/ijms23137175] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 06/20/2022] [Accepted: 06/23/2022] [Indexed: 01/27/2023] Open
Abstract
Increasing evidence links chronic neurodegenerative diseases with neuroinflammation; it is known that neuroprotective agents are capable of modulating the inflammatory processes, that occur with the onset of neurodegeneration pathologies. Here, with the intention of providing a means for active compounds’ screening, a dysregulation of neuronal inflammatory marker genes was induced and subjected to neuroprotective active principles, with the aim of selecting a set of inflammatory marker genes linked to neurodegenerative diseases. Considering the important role of microglia in neurodegeneration, a murine co-culture of hippocampal cells and inflamed microglia cells was set up. The evaluation of differentially expressed genes and subsequent in silico analysis showed the main dysregulated genes in both cells and the principal inflammatory processes involved in the model. Among the identified genes, a well-defined set was chosen, selecting those in which a role in human neurodegenerative progression in vivo was already defined in literature, matched with the rate of prediction derived from the Principal Component Analysis (PCA) of in vitro treatment-affected genes variation. The obtained panel of dysregulated target genes, including Cxcl9 (Chemokine (C-X-C motif) ligand 9), C4b (Complement Component 4B), Stc1 (Stanniocalcin 1), Abcb1a (ATP Binding Cassette Subfamily B Member 1), Hp (Haptoglobin) and Adm (Adrenomedullin), can be considered an in vitro tool to select old and new active compounds directed to neuroinflammation.
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Affiliation(s)
- Marcella Massimini
- Faculty of Veterinary Medicine, University of Teramo, 64100 Teramo, Italy
- Correspondence:
| | - Benedetta Bachetti
- R&D Division, C.I.A.M. Srl, 63100 Ascoli Piceno, Italy; (B.B.); (E.D.V.); (A.B.)
| | - Elena Dalle Vedove
- R&D Division, C.I.A.M. Srl, 63100 Ascoli Piceno, Italy; (B.B.); (E.D.V.); (A.B.)
| | - Alessia Benvenga
- R&D Division, C.I.A.M. Srl, 63100 Ascoli Piceno, Italy; (B.B.); (E.D.V.); (A.B.)
| | - Francesco Di Pierro
- Velleja Research, 20125 Milan, Italy;
- Digestive Endoscopy Unit and Gastroenterology, Fondazione Poliambulanza, 25124 Brescia, Italy
| | - Nicola Bernabò
- Faculty of Bioscience and Technology for Food, Agriculture and Environment, University of Teramo, 64100 Teramo, Italy;
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16
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Hisaoka-Nakashima K, Ohata K, Yoshimoto N, Tokuda S, Yoshii N, Nakamura Y, Wang D, Liu K, Wake H, Yoshida T, Ago Y, Hashimoto K, Nishibori M, Morioka N. High-mobility group box 1-mediated hippocampal microglial activation induces cognitive impairment in mice with neuropathic pain. Exp Neurol 2022; 355:114146. [PMID: 35738416 DOI: 10.1016/j.expneurol.2022.114146] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 06/09/2022] [Accepted: 06/14/2022] [Indexed: 11/28/2022]
Abstract
Clinical evidence indicates that cognitive impairment is a common comorbidity of chronic pain, including neuropathic pain, but the mechanism underlying cognitive impairment remains unclear. Neuroinflammation plays a critical role in the development of both neuropathic pain and cognitive impairment. High-mobility group box 1 (HMGB1) is a proinflammatory molecule and could be involved in neuroinflammation-mediated cognitive impairment in the neuropathic pain state. Hippocampal microglial activation in mice has been associated with cognitive impairment. Thus, the current study examined a potential role of HMGB1 and microglial activation in cognitive impairment in mice with neuropathic pain due to a partial sciatic nerve ligation (PSNL). Mice developed cognitive impairment over two weeks, but not one week, after nerve injury. Nerve-injured mice demonstrated decreased nuclear fraction HMGB1, suggesting increased extracellular release of HMGB1. Furthermore, two weeks after PSNL, significant microglia activation was observed in hippocampus. Inhibition of microglial activation with minocycline, local hippocampal microglia depletion with clodronate liposome, or blockade of HMGB1 with either glycyrrhizic acid (GZA) or anti-HMGB1 antibody in PSNL mice reduced hippocampal microglia activation and ameliorated cognitive impairment. Other changes in the hippocampus of PSNL mice potentially related to cognitive impairment, including decreased hippocampal neuron dendrite length and spine densities and decreased α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) glutamate receptor (AMPAR) subunits, were prevented with anti-HMGB1 antibody treatment. The current findings suggest that neuro-inflammation involves a number of cellular-level changes and microglial activation. Blocking neuro-inflammation, particularly through blocking HMGB1 could be a novel approach to reducing co-morbidities such as cognitive impairment associated with neuropathic pain.
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Affiliation(s)
- Kazue Hisaoka-Nakashima
- Department of Pharmacology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima, Japan
| | - Kazuto Ohata
- Department of Pharmacology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima, Japan
| | - Natsuki Yoshimoto
- Department of Pharmacology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima, Japan
| | - Shintarou Tokuda
- Department of Pharmacology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima, Japan
| | - Nanako Yoshii
- Department of Pharmacology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima, Japan
| | - Yoki Nakamura
- Department of Pharmacology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima, Japan
| | - Dengli Wang
- Department of Pharmacology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Shikata, Okayama, Japan
| | - Keyue Liu
- Department of Pharmacology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Shikata, Okayama, Japan
| | - Hidenori Wake
- Department of Pharmacology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Shikata, Okayama, Japan
| | - Takayuki Yoshida
- Department of Neurophysiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima, Japan
| | - Yukio Ago
- Department of Cellular and Molecular Pharmacology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima, Japan
| | - Kouichi Hashimoto
- Department of Neurophysiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima, Japan
| | - Masahiro Nishibori
- Department of Translational Research & Drug Development, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Shikata, Okayama, Japan
| | - Norimitsu Morioka
- Department of Pharmacology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima, Japan.
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17
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Bloom O, Tracey KJ, Pavlov VA. Exploring the vagus nerve and the inflammatory reflex for therapeutic benefit in chronic spinal cord injury. Curr Opin Neurol 2022; 35:249-257. [PMID: 35102123 PMCID: PMC9258775 DOI: 10.1097/wco.0000000000001036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE OF REVIEW To describe features and implications of chronic systemic inflammation in individuals with spinal cord injury (SCI) and to summarize the growing therapeutic possibilities to explore the vagus nerve-mediated inflammatory reflex in this context. RECENT FINDINGS The discovery of the inflammatory reflex provides a rationale to explore neuromodulation modalities, that is, electrical vagus nerve stimulation and pharmacological cholinergic modalities to regulate inflammation after SCI. SUMMARY Inflammation in individuals with SCI may negatively impact functional recovery and medical consequences after SCI. Exploring the potential of the vagus nerve-based inflammatory reflex to restore autonomic regulation and control inflammation may provide a novel approach for functional improvement in SCI.
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Affiliation(s)
- Ona Bloom
- The Feinstein Institutes for Medical Research, Northwell Health, Manhasset
- Donald and Barbara Zucker School of Medicine, Hempstead, New York, USA
| | - Kevin J. Tracey
- The Feinstein Institutes for Medical Research, Northwell Health, Manhasset
- Donald and Barbara Zucker School of Medicine, Hempstead, New York, USA
| | - Valentin A. Pavlov
- The Feinstein Institutes for Medical Research, Northwell Health, Manhasset
- Donald and Barbara Zucker School of Medicine, Hempstead, New York, USA
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18
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Progress in the Development of Graphene-Based Biomaterials for Tissue Engineering and Regeneration. MATERIALS 2022; 15:ma15062164. [PMID: 35329615 PMCID: PMC8955908 DOI: 10.3390/ma15062164] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 03/10/2022] [Accepted: 03/11/2022] [Indexed: 12/16/2022]
Abstract
Over the last few decades, tissue engineering has become an important technology for repairing and rebuilding damaged tissues and organs. The scaffold plays an important role and has become a hot pot in the field of tissue engineering. It has sufficient mechanical and biochemical properties and simulates the structure and function of natural tissue to promote the growth of cells inward. Therefore, graphene-based nanomaterials (GBNs), such as graphene and graphene oxide (GO), have attracted wide attention in the field of biomedical tissue engineering because of their unique structure, large specific surface area, good photo-thermal effect, pH response and broad-spectrum antibacterial properties. In this review, the structure and properties of typical GBNs are summarized, the progress made in the development of GBNs in soft tissue engineering (including skin, muscle, nerve and blood vessel) are highlighted, the challenges and prospects of the application of GBNs in soft tissue engineering have prospected.
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Chen H, Jiang L, Zhang D, Chen J, Luo X, Xie Y, Han T, Wang L, Zhang Z, Zhou X, Yan H. Exploring the Correlation Between the Regulation of Macrophages by Regulatory T Cells and Peripheral Neuropathic Pain. Front Neurosci 2022; 16:813751. [PMID: 35237123 PMCID: PMC8882923 DOI: 10.3389/fnins.2022.813751] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 01/25/2022] [Indexed: 11/13/2022] Open
Abstract
ObjectiveIntractable pain after peripheral nerve injury has become a major concern in the field of pain. Current evidence shows that routine medications or surgical treatment is associated with inconsistent results and different curative effects. Stable and effective treatment methods in clinical practice are also lacking. To date, there is no consensus on the pathophysiological mechanisms of pain. The present study investigates the potential regulatory role of regulatory T cells in the differentiation of macrophages on dorsal root ganglion (DRG) and explores the mechanism of nociceptive signals in the signal transfer station. The findings are expected to guide the prevention of various types of peripheral neuropathic pain.MethodsThirty-six male Sprague Dawley (SD) rats and 18 male Nude rats, of equal weight (250–300g), were used in this study. The rats were divided into 3 groups: SD rat sciatic nerve transection group (SNT group, n = 18), SD rat nerve transection experimental group (SNT/RAPA group, n = 18) and Nude rat nerve transection experimental group (SNT/NUDE group, n = 18). The behavior related to neuropathic pain of animals were comprehensively evaluated in all groups. Furthermore, we analyzed the degree of neuroma development, histology, gene, and protein expression, and compared their correlation with the ultrastructural changes of M1/M2 type differentiation of macrophages in DRG.ResultsSciatic nerve transection (SNT), induced the aggregation of several types of macrophages in lumbar DRG of SD rats leading to a higher ratio of M1/M2. Following the inhibition of the M1 type polarization of macrophages, axon outgrowth increased significantly. A significantly lower average autotomy score was reported in the SNT/NUDE group (*p < 0.05) and the SNT/RAPA group (@p < 0.05) as compared to that of the SNT group. The SNT/NUDE group showed no noticeable neuroma formation 30 days after the nerve transection. However, bulbous neuromas were observed in the nerve stumps of both the SNT control and SNT/RAPA groups. Immunofluorescence staining revealed a significant decrease in the proportion of M1/M2 macrophages in lumbar DRG of the SNT/NUDE group (**p < 0.001) and the SNT/RAPA group (@p < 0.05) compared to the SNT group. The expression of pain-related proteins was also decreased (@p < 0.05, *p < 0.05,**p < 0.001). Also, the expression of alpha-smooth muscle actin (α-SMA), neurofilament 200 (NF-200), and nerve growth factor low-affinity receptor p75 were significantly down-regulated in the nerve tissue (@p < 0.05, @@p < 0.001, **p < 0.001).ConclusionM1/M2 type differentiation of macrophages on DRG plays a significant role in the formation of traumatic painful neuroma after neurotomy. In combination with our previous study, the results of this study suggest that regulatory T cells reduce the ratio of M1/M2 macrophages and alleviate the pain of neuroma by regulating the polarization direction of macrophages on neuroma. These findings provide key insights into developing new strategies to manage painful neuroma.
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Affiliation(s)
- Hongyu Chen
- Division of Hand Surgery, Department of Orthopedics, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Wenzhou, China
- Key Laboratory of Orthopedics of Zhejiang Province, Wenzhou, China
- The Second School of Medicine, Wenzhou Medical University, Wenzhou, China
| | - Liangfu Jiang
- Division of Hand Surgery, Department of Orthopedics, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Wenzhou, China
- Key Laboratory of Orthopedics of Zhejiang Province, Wenzhou, China
| | - Dupiao Zhang
- Division of Hand Surgery, Department of Orthopedics, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Wenzhou, China
- Key Laboratory of Orthopedics of Zhejiang Province, Wenzhou, China
- The Second School of Medicine, Wenzhou Medical University, Wenzhou, China
| | - Jianpeng Chen
- Division of Hand Surgery, Department of Orthopedics, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Wenzhou, China
- Key Laboratory of Orthopedics of Zhejiang Province, Wenzhou, China
- The Second School of Medicine, Wenzhou Medical University, Wenzhou, China
| | - Xiaobin Luo
- Division of Hand Surgery, Department of Orthopedics, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Wenzhou, China
- Key Laboratory of Orthopedics of Zhejiang Province, Wenzhou, China
| | - Yutong Xie
- Key Laboratory of Orthopedics of Zhejiang Province, Wenzhou, China
- The Second School of Medicine, Wenzhou Medical University, Wenzhou, China
| | - Tao Han
- Division of Hand Surgery, Department of Orthopedics, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Wenzhou, China
- Key Laboratory of Orthopedics of Zhejiang Province, Wenzhou, China
- The Second School of Medicine, Wenzhou Medical University, Wenzhou, China
| | - Liang Wang
- Division of Hand Surgery, Department of Orthopedics, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Wenzhou, China
- Key Laboratory of Orthopedics of Zhejiang Province, Wenzhou, China
- The Second School of Medicine, Wenzhou Medical University, Wenzhou, China
| | - Zhe Zhang
- Division of Hand Surgery, Department of Orthopedics, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Wenzhou, China
- Key Laboratory of Orthopedics of Zhejiang Province, Wenzhou, China
- The Second School of Medicine, Wenzhou Medical University, Wenzhou, China
| | - Xijie Zhou
- Division of Hand Surgery, Department of Orthopedics, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Wenzhou, China
- Key Laboratory of Orthopedics of Zhejiang Province, Wenzhou, China
- *Correspondence: Xijie Zhou,
| | - Hede Yan
- Division of Hand Surgery, Department of Orthopedics, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Wenzhou, China
- Key Laboratory of Orthopedics of Zhejiang Province, Wenzhou, China
- Hede Yan,
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20
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Shao S, Xu CB, Chen CJ, Shi GN, Guo QL, Zhou Y, Wei YZ, Wu L, Shi JG, Zhang TT. Divanillyl sulfone suppresses NLRP3 inflammasome activation via inducing mitophagy to ameliorate chronic neuropathic pain in mice. J Neuroinflammation 2021; 18:142. [PMID: 34162415 PMCID: PMC8223331 DOI: 10.1186/s12974-021-02178-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 05/19/2021] [Indexed: 12/20/2022] Open
Abstract
Background Chronic neuropathic pain is a frequent sequel to peripheral nerve injury and maladaptive nervous system function. Divanillyl sulfone (DS), a novel structural derivative of 4,4′-dihydroxydibenzyl sulfoxide from a traditional Chinese medicine Gastrodia elata with anti-nociceptive effects, significantly alleviated neuropathic pain following intrathecal injection. Here, we aimed to investigate the underlying mechanisms of DS against neuropathic pain. Methods A chronic constrictive injury (CCI) mouse model of neuropathic pain induced by sciatic nerve ligation was performed to evaluate the effect of DS by measuring the limb withdrawal using Von Frey filament test. Immunofluorescence staining was used to assess the cell localizations and expressions of Iba-1, ASC, NLRP3, and ROS, the formation of autolysosome. The levels of NLRP3-related proteins (caspase-1, NLRP3, and IL-1β), mitophagy-related proteins (LC3, Beclin-1, and p62), and apoptosis-related proteins (Bcl-XL and Bax) were detected by Western blotting. The apoptosis of BV-2 cell and caspase activity were evaluated by flow cytometry. Results DS significantly alleviated the neuropathic pain by increasing the mechanical withdrawal threshold and inhibiting the activation of NLRP3 in CCI-induced model mice. Our findings indicated that DS promoted the mitophagy by increasing the LC3II and Beclin 1 and decreasing the levels of p62 protein in BV-2 cell. This is accompanied by the inhibition of NLRP3 activation, which was shown as inhibited the expression of NLRP3 in lysates as well as the secretion of mature caspase-1 p10 and IL-1β p17 in supernatants in cultured BV-2 microglia. In addition, DS could promote mitophagy-induced improvement of dysfunctional mitochondria by clearing intracellular ROS and restoring mitochondrial membrane potential. Conclusion Together, our findings demonstrated that DS ameliorate chronic neuropathic pain in mice by suppressing NLRP3 inflammasome activation induced by mitophagy in microglia. DS may be a promising therapeutic agent for chronic neuropathic pain. Supplementary Information The online version contains supplementary material available at 10.1186/s12974-021-02178-z.
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Affiliation(s)
- Shuai Shao
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100050, China
| | - Cheng-Bo Xu
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100050, China
| | - Cheng-Juan Chen
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100050, China
| | - Gao-Na Shi
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100050, China
| | - Qing-Lan Guo
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100050, China
| | - Yu Zhou
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100050, China
| | - Ya-Zi Wei
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100050, China
| | - Lei Wu
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100050, China
| | - Jian-Gong Shi
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100050, China.
| | - Tian-Tai Zhang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100050, China.
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21
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Raja SN, Ringkamp M, Guan Y, Campbell JN. John J. Bonica Award Lecture: Peripheral neuronal hyperexcitability: the "low-hanging" target for safe therapeutic strategies in neuropathic pain. Pain 2021; 161 Suppl 1:S14-S26. [PMID: 33090736 DOI: 10.1097/j.pain.0000000000001838] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
| | - Matthias Ringkamp
- Neurological Surgery, Department of Neurosurgery, Johns Hopkins University, School of Medicine, Baltimore, MD, United States
| | - Yun Guan
- Departments of Anesthesiology and Critical Care Medicine and.,Neurological Surgery, Department of Neurosurgery, Johns Hopkins University, School of Medicine, Baltimore, MD, United States
| | - James N Campbell
- Neurological Surgery, Department of Neurosurgery, Johns Hopkins University, School of Medicine, Baltimore, MD, United States
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22
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Morrison D, Arcese AA, Parrish J, Gibbs K, Beaufort A, Herman P, Stein AB, Bloom O. Systemic gene expression profiles according to pain types in individuals with chronic spinal cord injury. Mol Pain 2021; 17:17448069211007289. [PMID: 33853401 PMCID: PMC8053765 DOI: 10.1177/17448069211007289] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Pain affects most individuals with traumatic spinal cord injury (SCI). Major pain types after SCI are neuropathic or nociceptive, often experienced concurrently. Pain after SCI may be refractory to treatments and negatively affects quality of life. Previously, we analyzed whole blood gene expression in individuals with chronic SCI compared to able-bodied (AB) individuals. Most participants with SCI reported pain (N = 19/28). Here, we examined gene expression of participants with SCI by pain status. Compared to AB, participants with SCI with pain had 468 differentially expressed (DE) genes; participants without pain had 564 DE genes (FDR < 0.05). Among DE genes distinct to participants with SCI with pain, Gene Ontology Biological Process (GOBP) analysis showed upregulated genes were enriched in categories related to T cell activation or inflammation; downregulated genes were enriched in categories related to protein proteolysis and catabolism. Although most participants with pain reported multiple pain types concurrently, we performed a preliminary comparison of gene expression by worst pain problem type. Compared to AB, participants with SCI who ranked neuropathic (N = 9) as worst had one distinct DE gene (TMEM156); participants who ranked nociceptive (N = 10) as worst had 61 distinct DE genes (FDR < 0.05). In the nociceptive group, the GOBP category with the lowest P-value identified among upregulated genes was “positive regulation of T cell activation”; among downregulated genes it was “receptor tyrosine kinase binding”. An exploratory comparison of pain groups by principal components analysis also showed that the nociceptive group was enriched in T-cell related genes. A correlation analysis identified genes significantly correlated with pain intensity in the neuropathic or nociceptive groups (N = 145, 65, respectively, Pearson’s correlation r > 0.8). While this pilot study highlights challenges of identifying gene expression profiles that correlate with specific types of pain in individuals with SCI, it suggests that T-cell signaling should be further investigated in this context.
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Affiliation(s)
- Debra Morrison
- Institute of Molecular Medicine, The Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | - Anthony A Arcese
- Institute of Molecular Medicine, The Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | - Janay Parrish
- Donald and Barbara Zucker School of Medicine at Hofstra-Northwell, Hempstead, NY, USA
| | - Katie Gibbs
- Institute of Molecular Medicine, The Feinstein Institutes for Medical Research, Manhasset, NY, USA.,Department of Physical Medicine and Rehabilitation, Zucker School of Medicine at Hofstra-Northwell, Hempstead, NY, USA
| | - Andrew Beaufort
- Institute of Molecular Medicine, The Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | - Paige Herman
- Institute of Molecular Medicine, The Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | - Adam B Stein
- Department of Physical Medicine and Rehabilitation, Zucker School of Medicine at Hofstra-Northwell, Hempstead, NY, USA
| | - Ona Bloom
- Institute of Molecular Medicine, The Feinstein Institutes for Medical Research, Manhasset, NY, USA.,Department of Physical Medicine and Rehabilitation, Zucker School of Medicine at Hofstra-Northwell, Hempstead, NY, USA.,Department of Molecular Medicine, Zucker School of Medicine at Hofstra-Northwell, Hempstead, NY, USA
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23
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Sham surgeries for central and peripheral neural injuries persistently enhance pain-avoidance behavior as revealed by an operant conflict test. Pain 2020; 160:2440-2455. [PMID: 31323014 DOI: 10.1097/j.pain.0000000000001642] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Studies using rodent models of neuropathic pain use sham surgery control procedures that cause deep tissue damage. Sham surgeries would thus be expected to induce potentially long-lasting postsurgical pain, but little evidence for such pain has been reported. Operant tests of voluntary behavior can reveal negative motivational and cognitive aspects of pain that may provide sensitive tools for detecting pain-related alterations. In a previously described operant mechanical conflict test involving lengthy familiarization and training, rodents freely choose to either escape from a brightly lit chamber by crossing sharp probes or refuse to cross. Here, we describe a brief (2-day) mechanical conflict protocol that exploits rats' innate exploratory response to a novel environment to detect persistently enhanced pain-avoidance behavior after sham surgeries for 2 neural injury models: thoracic spinal cord injury and chronic constriction injury of the sciatic nerve. Pitting the combined motivations to avoid the bright light and to explore the novel device against pain from crossing noxious probes disclosed a conflicting, hyperalgesia-related reluctance to repeatedly cross the probes after injury. Rats receiving standard sham surgeries demonstrated enhanced pain-like avoidance behavior compared with naive controls, and this behavior was similar to that of corresponding chronic constriction injury or spinal cord injury rats weeks or months after injury. In the case of sham surgery for spinal cord injury, video analysis of voluntary exploratory behavior directed at the probes revealed enhanced forepaw withdrawal responses. These findings have important implications for preclinical investigations into behavioral alterations and physiological mechanisms associated with postsurgical and neuropathic pain.
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24
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Cardiovascular Autonomic Dysfunction in Spinal Cord Injury: Epidemiology, Diagnosis, and Management. Semin Neurol 2020; 40:550-559. [PMID: 32906175 DOI: 10.1055/s-0040-1713885] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Spinal cord injury (SCI) disrupts autonomic circuits and impairs synchronistic functioning of the autonomic nervous system, leading to inadequate cardiovascular regulation. Individuals with SCI, particularly at or above the sixth thoracic vertebral level (T6), often have impaired regulation of sympathetic vasoconstriction of the peripheral vasculature and the splanchnic circulation, and diminished control of heart rate and cardiac output. In addition, impaired descending sympathetic control results in changes in circulating levels of plasma catecholamines, which can have a profound effect on cardiovascular function. Although individuals with lesions below T6 often have normal resting blood pressures, there is evidence of increases in resting heart rate and inadequate cardiovascular response to autonomic provocations such as the head-up tilt and cold face tests. This manuscript reviews the prevalence of cardiovascular disorders given the level, duration and severity of SCI, the clinical presentation, diagnostic workup, short- and long-term consequences, and empirical evidence supporting management strategies to treat cardiovascular dysfunction following a SCI.
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25
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Contribution of T-Type Calcium Channels to Spinal Cord Injury-Induced Hyperexcitability of Nociceptors. J Neurosci 2020; 40:7229-7240. [PMID: 32839232 DOI: 10.1523/jneurosci.0517-20.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 07/22/2020] [Accepted: 07/30/2020] [Indexed: 01/24/2023] Open
Abstract
A hyperexcitable state and spontaneous activity of nociceptors have been suggested to play a critical role in the development of chronic neuropathic pain following spinal cord injury (SCI). In male rats, we employed the action potential-clamp technique to determine the underlying ionic mechanisms responsible for driving SCI-nociceptors to a hyperexcitable state and for triggering their spontaneous activity. We found that the increased activity of low voltage activated T-type calcium channels induced by the injury sustains the bulk (∼60-70%) of the inward current active at subthreshold voltages during the interspike interval in SCI-nociceptors, with a modest contribution (∼10-15%) from tetrodotoxin (TTX)-sensitive and TTX-resistant sodium channels and hyperpolarization-activated cyclic nucleotide-gated (HCN) channels. In current-clamp recordings, inhibition of T-type calcium channels with 1 μm TTA-P2 reduced both the spontaneous and the evoked firing in response to current injections in SCI-nociceptors to a level similar to sham-nociceptors. Electrophysiology in vitro was then combined with the conditioned place preference (CPP) paradigm to determine the relationship between the increased activity of T-type channels in SCI-nociceptors and chronic neuropathic pain following SCI. The size of the interspike T-type calcium current recorded from nociceptors isolated from SCI rats showing TTA-P2-induced CPP (responders) was ∼6 fold greater than the interspike T-type calcium current recorded from nociceptors isolated from SCI rats without TTA-P2-induced CPP (non-responders). Taken together, our data suggest that the increased activity of T-type calcium channels induced by the injury plays a primary role in driving SCI-nociceptors to a hyperexcitable state and contributes to chronic neuropathic pain following SCI.SIGNIFICANCE STATEMENT Chronic neuropathic pain is a major comorbidity of spinal cord injury (SCI), affecting up to 70-80% of patients. Anticonvulsant and tricyclic antidepressant drugs are first line analgesics used to treat SCI-induced neuropathic pain, but their efficacy is very limited. A hyperexcitable state and spontaneous activity of SCI-nociceptors have been proposed as a possible underlying cause for the development of chronic neuropathic pain following SCI. Here, we show that the increased activity of T-type calcium channels induced by the injury plays a major role in driving SCI-nociceptors to a hyperexcitable state and for promoting their spontaneous activity, suggesting that T-type calcium channels may represent a pharmacological target to treat SCI-induced neuropathic pain.
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26
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da Silva MD, Guginski G, Sato KL, Sanada LS, Sluka KA, Santos AR. Persistent pain induces mood problems and memory loss by the involvement of cytokines, growth factors, and supraspinal glial cells. Brain Behav Immun Health 2020; 7:100118. [PMID: 34589875 PMCID: PMC8474185 DOI: 10.1016/j.bbih.2020.100118] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Revised: 07/20/2020] [Accepted: 07/23/2020] [Indexed: 12/27/2022] Open
Abstract
Lesions of peripheral nerves lead to pain, hyperalgesia, and psychological comorbidities. However, the relationship between mood disorders and neuropathic pain is unclear, as well as the underlying mechanisms related to these disorders. Therefore, we investigated if nerve injury induces depression, anxiety, and cognitive impairment and if there were changes in cytokines, growth factors, and glial cell activation in cortical sites involved in processing pain and mood in animals with nerve injury. Nerve injury was induced by partial sciatic nerve ligation (PSNL) in male Swiss mice and compared to sham-operated animals. Nociceptive behavioral tests to mechanical and thermal (heat and cold) stimuli confirmed the development of hyperalgesia. We further examined mood disorders and memory behaviors. We show nerve injury induces a decrease in mechanical withdrawal thresholds and thermal latency to heat and cold. We also show that nerve injury causes depressive-like and anxiety-like behaviors as well as impairment in short-term memory in mice. There were increases in proinflammatory cytokines as well as Brain-Derived Neurotrophic Factor (BDNF) in the injured nerve. In the spinal cord, there were increases in both pro and anti-inflammatory cytokines, as well as of BDNF and Nerve Growth Factor (NGF). Further, in our data was a decrease in the density of microglia and astrocytes in the hippocampus and increased microglial density in the prefrontal cortex, areas associated with neuropathic pain conditions.
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Affiliation(s)
- Morgana D. da Silva
- Laboratory of Neurobiology of Pain and Inflammation, Department of Physiological Sciences, Center for Biological Sciences, Federal University of Santa Catarina, University Campus, Trindade, Florianópolis, SC, 88040-900, Brazil
- Program of Pos-graduation in Neuroscience, Federal University of Santa Catarina, University Campus, Trindade, Florianópolis, SC, 88040-900, Brazil
| | - Giselle Guginski
- Department of Pharmacology, Center of Biological Sciences, Federal University of Santa Catarina, University Campus, Trindade, Florianópolis, SC, 88040-900, Brazil
| | - Karina L. Sato
- Department of Physical Therapy and Rehabilitation Science, Pain Research Program, University of Iowa, #1-252 MEB, Iowa City, IA, 52241, USA
| | - Luciana Sayuri Sanada
- Department of Physical Therapy and Rehabilitation Science, Pain Research Program, University of Iowa, #1-252 MEB, Iowa City, IA, 52241, USA
| | - Kathleen A. Sluka
- Department of Physical Therapy and Rehabilitation Science, Pain Research Program, University of Iowa, #1-252 MEB, Iowa City, IA, 52241, USA
| | - Adair R.S. Santos
- Laboratory of Neurobiology of Pain and Inflammation, Department of Physiological Sciences, Center for Biological Sciences, Federal University of Santa Catarina, University Campus, Trindade, Florianópolis, SC, 88040-900, Brazil
- Program of Pos-graduation in Neuroscience, Federal University of Santa Catarina, University Campus, Trindade, Florianópolis, SC, 88040-900, Brazil
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27
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Vacca V, Madaro L, De Angelis F, Proietti D, Cobianchi S, Orsini T, Puri PL, Luvisetto S, Pavone F, Marinelli S. Revealing the Therapeutic Potential of Botulinum Neurotoxin Type A in Counteracting Paralysis and Neuropathic Pain in Spinally Injured Mice. Toxins (Basel) 2020; 12:E491. [PMID: 32751937 PMCID: PMC7472120 DOI: 10.3390/toxins12080491] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 07/27/2020] [Accepted: 07/28/2020] [Indexed: 12/21/2022] Open
Abstract
Botulinum neurotoxin type A (BoNT/A) is a major therapeutic agent that has been proven to be a successful treatment for different neurological disorders, with emerging novel therapeutic indications each year. BoNT/A exerts its action by blocking SNARE complex formation and vesicle release through the specific cleavage of SNAP-25 protein; the toxin is able to block the release of pro-inflammatory molecules for months after its administration. Here we demonstrate the extraordinary capacity of BoNT/A to neutralize the complete paralysis and pain insensitivity induced in a murine model of severe spinal cord injury (SCI). We show that the toxin, spinally administered within one hour from spinal trauma, exerts a long-lasting proteolytic action, up to 60 days after its administration, and induces a complete recovery of muscle and motor function. BoNT/A modulates SCI-induced neuroglia hyperreactivity, facilitating axonal restoration, and preventing secondary cells death and damage. Moreover, we demonstrate that BoNT/A affects SCI-induced neuropathic pain after moderate spinal contusion, confirming its anti-nociceptive action in this kind of pain, as well. Our results provide the intriguing and real possibility to identify in BoNT/A a therapeutic tool in counteracting SCI-induced detrimental effects. Because of the well-documented BoNT/A pharmacology, safety, and toxicity, these findings strongly encourage clinical translation.
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Affiliation(s)
- Valentina Vacca
- CNR—National Research Council, Institute of Biochemistry and Cell Biology, 00015 Monterotondo Scalo (RM), Italy; (V.V.); (T.O.); (S.L.)
- IRCCS Santa Lucia Foundation, 00143 Roma, Italy; (L.M.); (F.D.A.); (D.P.)
| | - Luca Madaro
- IRCCS Santa Lucia Foundation, 00143 Roma, Italy; (L.M.); (F.D.A.); (D.P.)
- DAHFMO-Unit of Histology and Medical Embryology, Sapienza University of Rome, 00161 Rome, Italy
| | | | - Daisy Proietti
- IRCCS Santa Lucia Foundation, 00143 Roma, Italy; (L.M.); (F.D.A.); (D.P.)
- DAHFMO-Unit of Histology and Medical Embryology, Sapienza University of Rome, 00161 Rome, Italy
| | - Stefano Cobianchi
- Institute of Neurosciences and Department of Cell Biology, Physiology and Immunology, Universitat Autonoma de Barcelona, E-08193 Bellaterra, Spain;
| | - Tiziana Orsini
- CNR—National Research Council, Institute of Biochemistry and Cell Biology, 00015 Monterotondo Scalo (RM), Italy; (V.V.); (T.O.); (S.L.)
| | - Pier Lorenzo Puri
- Development, Aging and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA;
| | - Siro Luvisetto
- CNR—National Research Council, Institute of Biochemistry and Cell Biology, 00015 Monterotondo Scalo (RM), Italy; (V.V.); (T.O.); (S.L.)
| | - Flaminia Pavone
- CNR—National Research Council, Institute of Biochemistry and Cell Biology, 00015 Monterotondo Scalo (RM), Italy; (V.V.); (T.O.); (S.L.)
- IRCCS Santa Lucia Foundation, 00143 Roma, Italy; (L.M.); (F.D.A.); (D.P.)
| | - Sara Marinelli
- CNR—National Research Council, Institute of Biochemistry and Cell Biology, 00015 Monterotondo Scalo (RM), Italy; (V.V.); (T.O.); (S.L.)
- IRCCS Santa Lucia Foundation, 00143 Roma, Italy; (L.M.); (F.D.A.); (D.P.)
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28
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Donnelly CR, Andriessen AS, Chen G, Wang K, Jiang C, Maixner W, Ji RR. Central Nervous System Targets: Glial Cell Mechanisms in Chronic Pain. Neurotherapeutics 2020; 17:846-860. [PMID: 32820378 PMCID: PMC7609632 DOI: 10.1007/s13311-020-00905-7] [Citation(s) in RCA: 133] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Interactions between central glial cells and neurons in the pain circuitry are critical contributors to the pathogenesis of chronic pain. In the central nervous system (CNS), two major glial cell types predominate: astrocytes and microglia. Injuries or pathological conditions which evoke pain are concurrently associated with the presence of a reactive microglia or astrocyte state, which is characterized by a variety of changes in the morphological, molecular, and functional properties of these cells. In this review, we highlight the changes that reactive microglia and astrocytes undergo following painful injuries and insults and discuss the critical and interactive role these two cell types play in the initiation and maintenance of chronic pain. Additionally, we focus on several crucial mechanisms by which microglia and astrocytes contribute to chronic pain and provide commentary on the therapeutic promise of targeting these pathways. In particular, we discuss how the inflammasome in activated microglia drives maturation and release of key pro-inflammatory cytokines, which drive pain through neuronal- and glial regulations. Moreover, we highlight several potentially-druggable hemichannels and proteases produced by reactive microglia and astrocytes in pain states and discuss how these pathways regulate distinct phases during pain pathogenesis. We also review two emerging areas in chronic pain research: 1) sexually dimorphic glial cell signaling and 2) the role of oligodendrocytes. Finally, we highlight important considerations for potential pain therapeutics targeting glial cell mediators as well as questions that remain in our conceptual understanding of glial cell activation in pain states.
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Affiliation(s)
- Christopher R Donnelly
- Center for Translational Pain Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, NC, 27710, USA.
| | - Amanda S Andriessen
- Center for Translational Pain Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Gang Chen
- Center for Translational Pain Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Kaiyuan Wang
- Center for Translational Pain Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Changyu Jiang
- Center for Translational Pain Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, NC, 27710, USA
| | - William Maixner
- Center for Translational Pain Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Ru-Rong Ji
- Center for Translational Pain Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, NC, 27710, USA.
- Department of Neurobiology, Duke University Medical Center, Durham, NC, 27710, USA.
- Department of Cell Biology, Duke University Medical Center, Durham, NC, 27710, USA.
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29
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Moradi K, Golbakhsh M, Haghighi F, Afshari K, Nikbakhsh R, Khavandi MM, Faghani S, Badripour A, Etemadi A, Ashraf-Ganjouei A, Bagheri S, Dehpour AR. Inhibition of phosphodiesterase IV enzyme improves locomotor and sensory complications of spinal cord injury via altering microglial activity: Introduction of Roflumilast as an alternative therapy. Int Immunopharmacol 2020; 86:106743. [PMID: 32619958 DOI: 10.1016/j.intimp.2020.106743] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 06/06/2020] [Accepted: 06/23/2020] [Indexed: 02/02/2023]
Abstract
Despite the great search for an effective approach to minimize secondary injury in spinal cord injury (SCI) setting, there have been limited advances. Roflumilast is a selective inhibitor of phosphodiesterase 4 with potent anti-inflammatory properties. Here, we sought to explore Roflumilast efficacy in the improvement of locomotor and sensory deficits of SCI. In an animal setting, 50 male rats were randomly assigned to five groups: an SCI group receiving Placebo, three SCI groups receiving Roflumilast at the doses of 0.25, 0.5, and 1 mg/kg prior to T9 vertebra laminectomy, and a sham-operated group. Locomotor, mechanical, and thermal activities were evaluated for 28 days. At the end of the study, spinal cord samples were taken to assess the relative ratio of microglial subtypes, including M1 and M2, histopathological changes, levels of pro-inflammatory (TNF-α and IL-1β) and anti-inflammatory (IL-10) biomarkers, and cAMP level. Repeated measure analysis revealed significant effect for time-treatment interaction on locomotion [F (24, 270) = 280.7, p < 0.001], thermal sensitivity [F (16, 180) = 4.35, p < 0.001], and mechanical sensitivity [F (16, 180) = 7.96, p < 0.001]. As expected, Roflumilast significantly increased the expression of spinal cAMP. H&E staining exhibited lesser histopathological disruptions in Roflumilast-treated rodents. We also observed a significant reduction in the M1/M2 ratio (p values < 0.001) as well as in pro-inflammatory biomarkers following the administration of Roflumilast to the injured rats. Furthermore, IL-10 level was increased in rodents receiving 1 mg/kg of the reagent. In conclusion, the increased spinal cAMP following Roflumilast therapy might attenuate neuroinflammation via altering microglial activity; therefore, it could be considered as an alternative therapeutic agent for SCI complications.
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Affiliation(s)
- Kamyar Moradi
- Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran; Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammadreza Golbakhsh
- Department of Orthopedic Surgery, Sina Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Farinaz Haghighi
- Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Khashayar Afshari
- Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran; Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Rajan Nikbakhsh
- Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran; Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran; Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohammad Mahdi Khavandi
- Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Shahriar Faghani
- Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Abolfazl Badripour
- Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran; Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Ali Etemadi
- Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Amir Ashraf-Ganjouei
- Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Sayna Bagheri
- Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran; Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Ahmad Reza Dehpour
- Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran; Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran; Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
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Cao T, Matyas JJ, Renn CL, Faden AI, Dorsey SG, Wu J. Function and Mechanisms of Truncated BDNF Receptor TrkB.T1 in Neuropathic Pain. Cells 2020; 9:cells9051194. [PMID: 32403409 PMCID: PMC7290366 DOI: 10.3390/cells9051194] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 05/08/2020] [Accepted: 05/08/2020] [Indexed: 12/11/2022] Open
Abstract
Brain-derived neurotrophic factor (BDNF), a major focus for regenerative therapeutics, has been lauded for its pro-survival characteristics and involvement in both development and recovery of function within the central nervous system (CNS). However, studies of tyrosine receptor kinase B (TrkB), a major receptor for BDNF, indicate that certain effects of the TrkB receptor in response to disease or injury may be maladaptive. More specifically, imbalance among TrkB receptor isoforms appears to contribute to aberrant signaling and hyperpathic pain. A truncated isoform of the receptor, TrkB.T1, lacks the intracellular kinase domain of the full length receptor and is up-regulated in multiple CNS injury models. Such up-regulation is associated with hyperpathic pain, and TrkB.T1 inhibition reduces neuropathic pain in various experimental paradigms. Deletion of TrkB.T1 also limits astrocyte changes in vitro, including proliferation, migration, and activation. Mechanistically, TrkB.T1 is believed to act through release of intracellular calcium in astrocytes, as well as through interactions with neurotrophins, leading to cell cycle activation. Together, these studies support a potential role for astrocytic TrkB.T1 in hyperpathic pain and suggest that targeted strategies directed at this receptor may have therapeutic potential.
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Affiliation(s)
- Tuoxin Cao
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, MD 21201, USA; (T.C.); (J.J.M.); (A.I.F.)
| | - Jessica J. Matyas
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, MD 21201, USA; (T.C.); (J.J.M.); (A.I.F.)
| | - Cynthia L. Renn
- Department of Pain and Translational Symptom Science, University of Maryland School of Nursing, Baltimore, MD 21201, USA; (C.L.R.); (S.G.D.)
- Center to Advance Chronic Pain Research, University of Maryland, Baltimore, MD 21201, USA
| | - Alan I. Faden
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, MD 21201, USA; (T.C.); (J.J.M.); (A.I.F.)
- Center to Advance Chronic Pain Research, University of Maryland, Baltimore, MD 21201, USA
| | - Susan G. Dorsey
- Department of Pain and Translational Symptom Science, University of Maryland School of Nursing, Baltimore, MD 21201, USA; (C.L.R.); (S.G.D.)
- Center to Advance Chronic Pain Research, University of Maryland, Baltimore, MD 21201, USA
| | - Junfang Wu
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, MD 21201, USA; (T.C.); (J.J.M.); (A.I.F.)
- Center to Advance Chronic Pain Research, University of Maryland, Baltimore, MD 21201, USA
- Correspondence: ; Tel.: +1-410-706-5189
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Yasko JR, Moss IL, Mains RE. Transcriptional Profiling of Non-injured Nociceptors After Spinal Cord Injury Reveals Diverse Molecular Changes. Front Mol Neurosci 2019; 12:284. [PMID: 32038157 PMCID: PMC6988781 DOI: 10.3389/fnmol.2019.00284] [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] [Received: 08/21/2019] [Accepted: 11/08/2019] [Indexed: 01/01/2023] Open
Abstract
Traumatic spinal cord injury (SCI) has devastating implications for patients, including a high predisposition for developing chronic pain distal to the site of injury. Chronic pain develops weeks to months after injury, consequently, patients are treated after irreparable changes have occurred. Nociceptors are central to chronic pain; however, the diversity of this cellular population presents challenges to understanding mechanisms and attributing pain modalities to specific cell types. To begin to address how peripheral sensory neurons below the injury level may contribute to the below-level pain reported by SCI patients, we examined SCI-induced changes in gene expression in lumbar dorsal root ganglia (DRG) below the site of injury. SCI was performed at the T10 vertebral level, with injury produced by a vessel clip with a closing pressure of 15 g for 1 min. Alterations in gene expression produce long-term sensory changes, therefore, we were interested in studying SCI-induced transcripts before the onset of chronic pain, which may trigger changes in downstream signaling pathways and ultimately facilitate the transmission of pain. To examine changes in the nociceptor subpopulation in DRG distal to the site of injury, we retrograde labeled sensory neurons projecting to the hairy hindpaw skin with fluorescent dye and collected the corresponding lumbar (L2–L6) DRG 4 days post-injury. Following dissociation, labeled neurons were purified by fluorescence-activated cell sorting (FACS). RNA was extracted from sorted sensory neurons of naïve, sham, or SCI mice and sequenced. Transcript abundances validated that the desired population of nociceptors were isolated. Cross-comparisons to data sets from similar studies confirmed, we were able to isolate our cells of interest and identify a unique pattern of gene expression within a subpopulation of neurons projecting to the hairy hindpaw skin. Differential gene expression analysis showed high expression levels and significant transcript changes 4 days post-injury in SCI cell populations relevant to the onset of chronic pain. Regulatory interrelationships predicted by pathway analysis implicated changes within the synaptogenesis signaling pathway as well as networks related to inflammatory signaling mechanisms, suggesting a role for synaptic plasticity and a correlation with pro-inflammatory signaling in the transition from acute to chronic pain.
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Affiliation(s)
- Jessica R Yasko
- Department of Neuroscience, University of Connecticut Health Center, Farmington, CT, United States
| | - Isaac L Moss
- Department of Orthopedic Surgery and the Comprehensive Spine Center, University of Connecticut Health Center, Farmington, CT, United States
| | - Richard E Mains
- Department of Neuroscience, University of Connecticut Health Center, Farmington, CT, United States
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Walters ET. Adaptive mechanisms driving maladaptive pain: how chronic ongoing activity in primary nociceptors can enhance evolutionary fitness after severe injury. Philos Trans R Soc Lond B Biol Sci 2019; 374:20190277. [PMID: 31544606 DOI: 10.1098/rstb.2019.0277] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Chronic pain is considered maladaptive by clinicians because it provides no apparent protective or recuperative benefits. Similarly, evolutionary speculations have assumed that chronic pain represents maladaptive or evolutionarily neutral dysregulation of acute pain mechanisms. By contrast, the present hypothesis proposes that chronic pain can be driven by mechanisms that evolved to reduce increased vulnerability to attack from predators and aggressive conspecifics, which often target prey showing physical impairment after severe injury. Ongoing pain and anxiety persisting long after severe injury continue to enhance vigilance and behavioural caution, decreasing the heightened vulnerability to attack that results from motor impairment and disfigurement, thereby increasing survival and reproduction (fitness). This hypothesis is supported by evidence of animals surviving and reproducing after traumatic amputations, and by complex specializations that enable primary nociceptors to detect local and systemic signs of injury and inflammation, and to maintain low-frequency discharge that can promote ongoing pain indefinitely. Ongoing activity in nociceptors involves intricate electrophysiological and anatomical specializations, including inducible alterations in the expression of ion channels and receptors that produce persistent hyperexcitability and hypersensitivity to chemical signals of injury. Clinically maladaptive chronic pain may sometimes result from the recruitment of this powerful evolutionary adaptation to severe bodily injury. This article is part of the Theo Murphy meeting issue 'Evolution of mechanisms and behaviour important for pain'.
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Affiliation(s)
- Edgar T Walters
- Department of Integrative Biology and Pharmacology, McGovern Medical School at UTHealth, 6431 Fannin Street, Houston, TX 77030, USA
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Sabirzhanov B, Li Y, Coll-Miro M, Matyas JJ, He J, Kumar A, Ward N, Yu J, Faden AI, Wu J. Inhibition of NOX2 signaling limits pain-related behavior and improves motor function in male mice after spinal cord injury: Participation of IL-10/miR-155 pathways. Brain Behav Immun 2019; 80:73-87. [PMID: 30807841 PMCID: PMC6660361 DOI: 10.1016/j.bbi.2019.02.024] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 01/11/2019] [Accepted: 02/22/2019] [Indexed: 12/19/2022] Open
Abstract
NADPH oxidase (NOX2) is an enzyme that induces reactive oxygen species (ROS) and serves as a switch between the pro-inflammatory and neurorestorative microglial/macrophage phenotypes; such changes play an important role in neuropathic pain and motor dysfunction. Increased NOX2 expression after spinal cord injury (SCI) has been reported, and inhibition of NOX2 improves motor function. However, the underlying mechanisms of NOX2 in post-traumatic pain and motor deficit remain unexplored. In the present study, we report that depletion of NOX2 (NOX2-/-) or inhibition of NOX2 using NOX2ds-tat significantly reduced mechanical/thermal cutaneous hypersensitivity and motor dysfunction after moderate contusion SCI at T10 in male mice. Western blot (WB, 3 mm lesion area) and immunohistochemistry (IHC) showed that SCI elevates NOX2 expression predominantly in microglia/macrophages up to 8 weeks post-injury. Deletion of NOX2 significantly reduced CD11b+/CD45hiF4/80+ macrophage infiltration at 24 h post-injury detected by flow cytometry and 8-OHG+ ROS production at 8 weeks post-injury by IHC in both lesion area and lumbar enlargement. NOX2 deficiency also altered microglial/macrophage pro-inflammatory and anti-inflammatory balance towards the neurorestorative response. WB analysis showed robust increase of Arginase-1 and YM1 proteins in NOX2-/- mice. Furthermore, qPCR analysis showed significant up-regulation of anti-inflammatory cytokine IL-10 levels in NOX2-/- mice, associated with reduced microRNA-155 expression. These findings were confirmed in CD11b+ microglia/macrophages isolated from spinal cord at 3 days post-injury. Taken together, our data suggest an important role for IL-10/miR-155 pathway in regulating NOX2-mediated SCI-dysfunction. Thus, specific targeting of NOX2 may provide an effective strategy for treating neurological dysfunction in SCI patients.
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Affiliation(s)
- Boris Sabirzhanov
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, MD, 21201 USA
| | - Yun Li
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, MD, 21201 USA
| | - Marino Coll-Miro
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, MD, 21201 USA
| | - Jessica J. Matyas
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, MD, 21201 USA
| | - Junyun He
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, MD, 21201 USA
| | - Alok Kumar
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, MD, 21201 USA
| | - Nicole Ward
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, MD, 21201 USA
| | - Jingwen Yu
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, MD, 21201 USA
| | - Alan I. Faden
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, MD, 21201 USA.,Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, 21201 USA,University of Maryland Center to Advance Chronic Pain Research, University of Maryland, Baltimore, MD, 21201 USA
| | - Junfang Wu
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, MD 21201 USA; Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201 USA; University of Maryland Center to Advance Chronic Pain Research, University of Maryland, Baltimore, MD 21201 USA.
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Innovative mouse model mimicking human-like features of spinal cord injury: efficacy of Docosahexaenoic acid on acute and chronic phases. Sci Rep 2019; 9:8883. [PMID: 31222077 PMCID: PMC6586623 DOI: 10.1038/s41598-019-45037-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 05/28/2019] [Indexed: 02/08/2023] Open
Abstract
Traumatic spinal cord injury has dramatic consequences and a huge social impact. We propose a new mouse model of spinal trauma that induces a complete paralysis of hindlimbs, still observable 30 days after injury. The contusion, performed without laminectomy and deriving from the pressure exerted directly on the bone, mimics more closely many features of spinal injury in humans. Spinal cord was injured at thoracic level 10 (T10) in adult anesthetized female CD1 mice, mounted on stereotaxic apparatus and connected to a precision impactor device. Following severe injury, we evaluated motor and sensory functions, and histological/morphological features of spinal tissue at different time points. Moreover, we studied the effects of early and subchronic administration of Docosahexaenoic acid, investigating functional responses, structural changes proximal and distal to the lesion in primary and secondary injury phases, proteome modulation in injured spinal cord. Docosahexaenoic acid was able i) to restore behavioural responses and ii) to induce pro-regenerative effects and neuroprotective action against demyelination, apoptosis and neuroinflammation. Considering the urgent health challenge represented by spinal injury, this new and reliable mouse model together with the positive effects of docosahexaenoic acid provide important translational implications for promising therapeutic approaches for spinal cord injuries.
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Hisaoka-Nakashima K, Tomimura Y, Yoshii T, Ohata K, Takada N, Zhang FF, Nakamura Y, Liu K, Wake H, Nishibori M, Nakata Y, Morioka N. High-mobility group box 1-mediated microglial activation induces anxiodepressive-like behaviors in mice with neuropathic pain. Prog Neuropsychopharmacol Biol Psychiatry 2019; 92:347-362. [PMID: 30763674 DOI: 10.1016/j.pnpbp.2019.02.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 01/22/2019] [Accepted: 02/07/2019] [Indexed: 12/13/2022]
Abstract
Clinical evidence indicates that major depression is a common comorbidity of chronic pain, including neuropathic pain. However, the cellular basis for chronic pain-mediated major depression remains unclear. High-mobility group box 1 protein (HMGB1) has a key role in innate immune responses and appears to be have a role in mediating diverse disorders, including neuropathic pain and depression. The current study aimed to characterize neuropathic pain-induced changes in affect over time and to determine whether HMGB1 has a role in neuropathic pain-induced changes in affect. Neuropathic pain was induced by partial sciatic nerve ligation (PSNL) in mice. Anxiodepressive-like behaviors in mice were evaluated over 10 weeks, in the social interaction, forced swim, and novelty suppressed feeding tests. Mice developed anxiodepressive-like behavior 6 to 8 weeks after induction of neuropathy. Accompanying anxiodepressive-like behavior, increased HMGB1 protein and microglia activation were observed in frontal cortex at 8 weeks after PSNL. Intracerebroventricular administration of rHMGB1 in naïve mice induced anxiodepressive-like behavior and microglia activation. Blockage of HMGB1 in PSNL mice with glycyrrhizic acid (GZA) or anti-HMGB1 antibody reduced microglia activation and anxiodepressive-like behavior. These results indicate that PSNL-induced anxiodepressive-like behavior is likely mediated by HMGB1. Furthermore, the data indicate that inhibition of HMGB1-dependent microglia activation could be a strategy for the treatment of depression associated with neuropathic pain.
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Affiliation(s)
- Kazue Hisaoka-Nakashima
- Department of Pharmacology, Graduate School of Biomedical & Health Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima, Japan
| | - Yoshiaki Tomimura
- Department of Pharmacology, Graduate School of Biomedical & Health Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima, Japan
| | - Toshiki Yoshii
- Department of Pharmacology, Graduate School of Biomedical & Health Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima, Japan
| | - Kazuto Ohata
- Department of Pharmacology, Graduate School of Biomedical & Health Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima, Japan
| | - Naoki Takada
- Department of Pharmacology, Graduate School of Biomedical & Health Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima, Japan
| | - Fang Fang Zhang
- Department of Pharmacology, Graduate School of Biomedical & Health Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima, Japan; Institute of Pharmacology, Tawishan Medical University, 619 Changcheng Road, Taian, Shandong 271016, China
| | - Yoki Nakamura
- Department of Pharmacology, Graduate School of Biomedical & Health Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima, Japan
| | - Keyue Liu
- Department of Pharmacology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Shikata, Okayama, Japan
| | - Hidenori Wake
- Department of Pharmacology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Shikata, Okayama, Japan
| | - Masahiro Nishibori
- Department of Pharmacology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Shikata, Okayama, Japan
| | - Yoshihiro Nakata
- Department of Pharmacology, Graduate School of Biomedical & Health Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima, Japan
| | - Norimitsu Morioka
- Department of Pharmacology, Graduate School of Biomedical & Health Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima, Japan.
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Hu JZ, Rong ZJ, Li M, Li P, Jiang LY, Luo ZX, Duan CY, Cao Y, Lu HB. Silencing of lncRNA PKIA-AS1 Attenuates Spinal Nerve Ligation-Induced Neuropathic Pain Through Epigenetic Downregulation of CDK6 Expression. Front Cell Neurosci 2019; 13:50. [PMID: 30873006 PMCID: PMC6401634 DOI: 10.3389/fncel.2019.00050] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 02/01/2019] [Indexed: 01/07/2023] Open
Abstract
Neuropathic pain (NP) is among the most intractable comorbidities of spinal cord injury. Dysregulation of non-coding RNAs has also been implicated in the development of neuropathic pain. Here, we identified a novel lncRNA, PKIA-AS1, by using lncRNA array analysis in spinal cord tissue of spinal nerve ligation (SNL) model rats, and investigated the role of PKIA-AS1 in SNL-mediated neuropathic pain. We observed that PKIA-AS1 was significantly upregulated in SNL model rats and that PKIA-AS1 knockdown attenuated neuropathic pain progression. Alternatively, overexpression of PKIA-AS1 was sufficient to induce neuropathic pain-like symptoms in uninjured rats. We also found that PKIA-AS1 mediated SNL-induced neuropathic pain by directly regulating the expression and function of CDK6, which is essential for the initiation and maintenance of neuroinflammation and neuropathic pain. Therefore, our study identifies PKIA-AS1 as a novel therapeutic target for neuroinflammation related neuropathic pain.
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Affiliation(s)
- Jian-Zhong Hu
- Department of Spine Surgery, Xiangya Hospital, Central South University, Changsha, China.,Key Laboratory of Organ Injury, Aging and Regenerative Medicine of Hunan Province, Xiangya Hospital, Central South University, Changsha, China
| | - Zi-Jie Rong
- Department of Spine Surgery, Xiangya Hospital, Central South University, Changsha, China.,Key Laboratory of Organ Injury, Aging and Regenerative Medicine of Hunan Province, Xiangya Hospital, Central South University, Changsha, China
| | - Miao Li
- Department of Spine Surgery, Xiangya Hospital, Central South University, Changsha, China.,Key Laboratory of Organ Injury, Aging and Regenerative Medicine of Hunan Province, Xiangya Hospital, Central South University, Changsha, China
| | - Ping Li
- Department of Spine Surgery, Xiangya Hospital, Central South University, Changsha, China.,Key Laboratory of Organ Injury, Aging and Regenerative Medicine of Hunan Province, Xiangya Hospital, Central South University, Changsha, China.,Department of Obstetrics, Xiangya Hospital, Central South University, Changsha, China
| | - Li-Yuan Jiang
- Department of Spine Surgery, Xiangya Hospital, Central South University, Changsha, China.,Key Laboratory of Organ Injury, Aging and Regenerative Medicine of Hunan Province, Xiangya Hospital, Central South University, Changsha, China
| | - Zi-Xiang Luo
- Department of Spine Surgery, Xiangya Hospital, Central South University, Changsha, China.,Key Laboratory of Organ Injury, Aging and Regenerative Medicine of Hunan Province, Xiangya Hospital, Central South University, Changsha, China
| | - Chun-Yue Duan
- Department of Spine Surgery, Xiangya Hospital, Central South University, Changsha, China.,Key Laboratory of Organ Injury, Aging and Regenerative Medicine of Hunan Province, Xiangya Hospital, Central South University, Changsha, China
| | - Yong Cao
- Department of Spine Surgery, Xiangya Hospital, Central South University, Changsha, China.,Key Laboratory of Organ Injury, Aging and Regenerative Medicine of Hunan Province, Xiangya Hospital, Central South University, Changsha, China
| | - Hong-Bin Lu
- Key Laboratory of Organ Injury, Aging and Regenerative Medicine of Hunan Province, Xiangya Hospital, Central South University, Changsha, China.,Department of Sports Medicine, Xiangya Hospital, Central South University, Changsha, China
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38
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Spinal Cord Stimulation for Pain Treatment After Spinal Cord Injury. Neurosci Bull 2018; 35:527-539. [PMID: 30560438 DOI: 10.1007/s12264-018-0320-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 08/11/2018] [Indexed: 12/30/2022] Open
Abstract
In addition to restoration of bladder, bowel, and motor functions, alleviating the accompanying debilitating pain is equally important for improving the quality of life of patients with spinal cord injury (SCI). Currently, however, the treatment of chronic pain after SCI remains a largely unmet need. Electrical spinal cord stimulation (SCS) has been used to manage a variety of chronic pain conditions that are refractory to pharmacotherapy. Yet, its efficacy, benefit profiles, and mechanisms of action in SCI pain remain elusive, due to limited research, methodological weaknesses in previous clinical studies, and a lack of mechanistic exploration of SCS for SCI pain control. We aim to review recent studies and outline the therapeutic potential of different SCS paradigms for traumatic SCI pain. We begin with an overview of its manifestations, classification, potential underlying etiology, and current challenges for its treatment. The clinical evidence for using SCS in SCI pain is then reviewed. Finally, future perspectives of pre-clinical research and clinical study of SCS for SCI pain treatment are discussed.
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Odem MA, Bavencoffe AG, Cassidy RM, Lopez ER, Tian J, Dessauer CW, Walters ET. Isolated nociceptors reveal multiple specializations for generating irregular ongoing activity associated with ongoing pain. Pain 2018; 159:2347-2362. [PMID: 30015712 PMCID: PMC6193853 DOI: 10.1097/j.pain.0000000000001341] [Citation(s) in RCA: 105] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Ongoing pain has been linked to ongoing activity (OA) in human C-fiber nociceptors, but rodent models of pain-related OA have concentrated on allodynia rather than ongoing pain, and on OA generated in non-nociceptive Aβ fibers rather than C-fiber nociceptors. Little is known about how ongoing pain or nociceptor OA is generated. To define neurophysiological alterations underlying nociceptor OA, we have used isolated dorsal root ganglion neurons that continue to generate OA after removal from animals displaying ongoing pain. We subclassify OA as either spontaneous activity generated solely by alterations intrinsic to the active neuron or as extrinsically driven OA. Both types of OA were implicated previously in nociceptors in vivo and after isolation following spinal cord injury, which produces chronic ongoing pain. Using novel automated algorithms to analyze irregular changes in membrane potential, we have found, in a distinctive, nonaccommodating type of probable nociceptor, induction by spinal cord injury of 3 alterations that promote OA: (1) prolonged depolarization of resting membrane potential, (2) a hyperpolarizing shift in the voltage threshold for action potential generation, and (3) an increase in the incidence of large depolarizing spontaneous fluctuations (DSFs). Can DSFs also be enhanced acutely to promote OA in neurons from uninjured animals? A low dose of serotonin failed to change resting membrane potential but lowered action potential threshold. When combined with artificial depolarization to model inflammation, serotonin also strongly potentiated DSFs and OA. These findings reveal nociceptor specializations for generating OA that may promote ongoing pain in chronic and acute conditions.
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Affiliation(s)
- Max A. Odem
- Department of Integrative Biology and Pharmacology, McGovern Medical School at UTHealth, Houston, TX, USA
| | - Alexis G. Bavencoffe
- Department of Integrative Biology and Pharmacology, McGovern Medical School at UTHealth, Houston, TX, USA
| | - Ryan M. Cassidy
- Department of Integrative Biology and Pharmacology, McGovern Medical School at UTHealth, Houston, TX, USA
| | - Elia R. Lopez
- Department of Integrative Biology and Pharmacology, McGovern Medical School at UTHealth, Houston, TX, USA
| | - Jinbin Tian
- Department of Integrative Biology and Pharmacology, McGovern Medical School at UTHealth, Houston, TX, USA
| | - Carmen W. Dessauer
- Department of Integrative Biology and Pharmacology, McGovern Medical School at UTHealth, Houston, TX, USA
| | - Edgar T. Walters
- Department of Integrative Biology and Pharmacology, McGovern Medical School at UTHealth, Houston, TX, USA
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Chhaya SJ, Quiros-Molina D, Tamashiro-Orrego AD, Houlé JD, Detloff MR. Exercise-Induced Changes to the Macrophage Response in the Dorsal Root Ganglia Prevent Neuropathic Pain after Spinal Cord Injury. J Neurotrauma 2018; 36:877-890. [PMID: 30152715 DOI: 10.1089/neu.2018.5819] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Spinal cord injury (SCI) induces neuropathic pain that is refractory to treatment. Central and peripheral immune responses to SCI play critical roles in pain development. Although immune responses in the dorsal horn have been implicated in SCI-pain, immune mechanisms in the periphery, especially in the dorsal root ganglia (DRG), where nociceptor cell bodies reside, have not been well studied. Exercise is an immunomodulator, and we showed previously that early exercise after SCI reduces pain development. However, the mechanisms of exercise-mediated pain reduction are not understood. Therefore, we examined the 1) underlying immune differences in the spinal cord and DRG between rats with and without pain and 2) immunomodulatory effects of exercise in pain reduction. Rats were subjected to a unilateral contusion at C5 and tested for pain development using von Frey and mechanical conflict-avoidance paradigms. A subgroup of rats was exercised on forced running wheels starting at 5 days post-injury for 4 weeks. We observed greater microglial activation in the C7-C8 dorsal horn of rats with SCI-induced pain compared to rats with normal sensation, and early exercise reduced this activation independently of pain behavior. Further, abnormal pain sensation strongly correlated with an increased number of DRG macrophages. Importantly, exercise-treated rats that maintain normal sensation also have a lower number of macrophages in the DRG. Our data suggest that macrophage presence in the DRG may be an important effector of pain development, and early wheel walking exercise may mediate pain prevention by modulating the injury-induced macrophage response in the DRG. Further supportive evidence demonstrated that rats that developed pain despite exercise intervention still displayed a significantly elevated number of macrophages in the DRG. Collectively, these data suggest that macrophage presence in the DRG may be an amenable cellular target for future therapies.
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Affiliation(s)
- Soha J Chhaya
- Department of Neurobiology and Anatomy, Spinal Cord Research Center, College of Medicine Drexel University Philadelphia, Pennsylvania
| | - Daniel Quiros-Molina
- Department of Neurobiology and Anatomy, Spinal Cord Research Center, College of Medicine Drexel University Philadelphia, Pennsylvania
| | - Alessandra D Tamashiro-Orrego
- Department of Neurobiology and Anatomy, Spinal Cord Research Center, College of Medicine Drexel University Philadelphia, Pennsylvania
| | - John D Houlé
- Department of Neurobiology and Anatomy, Spinal Cord Research Center, College of Medicine Drexel University Philadelphia, Pennsylvania
| | - Megan Ryan Detloff
- Department of Neurobiology and Anatomy, Spinal Cord Research Center, College of Medicine Drexel University Philadelphia, Pennsylvania
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Gerber YN, Saint-Martin GP, Bringuier CM, Bartolami S, Goze-Bac C, Noristani HN, Perrin FE. CSF1R Inhibition Reduces Microglia Proliferation, Promotes Tissue Preservation and Improves Motor Recovery After Spinal Cord Injury. Front Cell Neurosci 2018; 12:368. [PMID: 30386212 PMCID: PMC6198221 DOI: 10.3389/fncel.2018.00368] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Accepted: 09/28/2018] [Indexed: 12/11/2022] Open
Abstract
Spinal cord injury (SCI) induces a pronounced neuroinflammation driven by activation and proliferation of resident microglia as well as infiltrating peripheral monocyte-derived macrophages. Depending on the time post-lesion, positive and detrimental influences of microglia/macrophages on axonal regeneration had been reported after SCI, raising the issue whether their modulation may represent an attractive therapeutic strategy. Colony-stimulating factor 1 (CSF1) regulates microglia/macrophages proliferation, differentiation and survival thus, pharmacological treatments using CSF1 receptor (CSF1R) inhibitors had been used to ablate microglia. We analyzed the effect of chronic (10 weeks) food diet containing GW2580 (a CSF1R inhibitor) in mice that underwent lateral spinal cord hemisection (HS) at vertebral thoracic level 9. Treatment started 4 weeks prior to SCI and continued until 6 weeks post-lesion. We first demonstrate that GW2580 treatment did not modify microglial response in non-injured spinal cords. Conversely, a strong decrease in proliferating microglia was observed following SCI. Second, we showed that GW2580 treatment improved some parameters of motor recovery in injured animals through better paw placement. Using in and ex vivo magnetic resonance imaging (MRI), we then established that GW2580 treatment had no effect on lesion extension and volume. However, histological analyses revealed that GW2580-treated animals had reduced gliosis and microcavity formation following SCI. In conclusion, CSF1R blockade using GW2580 specifically inhibits SCI-induced microglia/macrophages proliferation, reduces gliosis and microcavity formations and improves fine motor recovery after incomplete SCI. Preventing microglial proliferation may offer therapeutic approach to limit neuroinflammation, promote tissue preservation and motor recovery following SCI.
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Affiliation(s)
- Yannick Nicolas Gerber
- University of Montpellier, Montpellier, France.,INSERM, U1198, Montpellier, France.,EPHE, Paris, France
| | - Guillaume Patrick Saint-Martin
- University of Montpellier, Montpellier, France.,INSERM, U1198, Montpellier, France.,EPHE, Paris, France.,UMR 5221 CNRS, University of Montpellier, Montpellier, France
| | - Claire Mathilde Bringuier
- University of Montpellier, Montpellier, France.,INSERM, U1198, Montpellier, France.,EPHE, Paris, France
| | - Sylvain Bartolami
- University of Montpellier, Montpellier, France.,INSERM, U1198, Montpellier, France.,EPHE, Paris, France
| | | | - Harun Najib Noristani
- University of Montpellier, Montpellier, France.,INSERM, U1198, Montpellier, France.,EPHE, Paris, France
| | - Florence Evelyne Perrin
- University of Montpellier, Montpellier, France.,INSERM, U1198, Montpellier, France.,EPHE, Paris, France
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42
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González SL, Meyer L, Raggio MC, Taleb O, Coronel MF, Patte-Mensah C, Mensah-Nyagan AG. Allopregnanolone and Progesterone in Experimental Neuropathic Pain: Former and New Insights with a Translational Perspective. Cell Mol Neurobiol 2018; 39:523-537. [DOI: 10.1007/s10571-018-0618-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 08/31/2018] [Indexed: 02/06/2023]
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Walters ET. Nociceptive Biology of Molluscs and Arthropods: Evolutionary Clues About Functions and Mechanisms Potentially Related to Pain. Front Physiol 2018; 9:1049. [PMID: 30123137 PMCID: PMC6085516 DOI: 10.3389/fphys.2018.01049] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 07/16/2018] [Indexed: 01/15/2023] Open
Abstract
Important insights into the selection pressures and core molecular modules contributing to the evolution of pain-related processes have come from studies of nociceptive systems in several molluscan and arthropod species. These phyla, and the chordates that include humans, last shared a common ancestor approximately 550 million years ago. Since then, animals in these phyla have continued to be subject to traumatic injury, often from predators, which has led to similar adaptive behaviors (e.g., withdrawal, escape, recuperative behavior) and physiological responses to injury in each group. Comparisons across these taxa provide clues about the contributions of convergent evolution and of conservation of ancient adaptive mechanisms to general nociceptive and pain-related functions. Primary nociceptors have been investigated extensively in a few molluscan and arthropod species, with studies of long-lasting nociceptive sensitization in the gastropod, Aplysia, and the insect, Drosophila, being especially fruitful. In Aplysia, nociceptive sensitization has been investigated as a model for aversive memory and for hyperalgesia. Neuromodulator-induced, activity-dependent, and axotomy-induced plasticity mechanisms have been defined in synapses, cell bodies, and axons of Aplysia primary nociceptors. Studies of nociceptive sensitization in Drosophila larvae have revealed numerous molecular contributors in primary nociceptors and interacting cells. Interestingly, molecular contributors examined thus far in Aplysia and Drosophila are largely different, but both sets overlap extensively with those in mammalian pain-related pathways. In contrast to results from Aplysia and Drosophila, nociceptive sensitization examined in moth larvae (Manduca) disclosed central hyperactivity but no obvious peripheral sensitization of nociceptive responses. Squid (Doryteuthis) show injury-induced sensitization manifested as behavioral hypersensitivity to tactile and especially visual stimuli, and as hypersensitivity and spontaneous activity in nociceptor terminals. Temporary blockade of nociceptor activity during injury subsequently increased mortality when injured squid were exposed to fish predators, providing the first demonstration in any animal of the adaptiveness of nociceptive sensitization. Immediate responses to noxious stimulation and nociceptive sensitization have also been examined behaviorally and physiologically in a snail (Helix), octopus (Adopus), crayfish (Astacus), hermit crab (Pagurus), and shore crab (Hemigrapsus). Molluscs and arthropods have systems that suppress nociceptive responses, but whether opioid systems play antinociceptive roles in these phyla is uncertain.
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Affiliation(s)
- Edgar T Walters
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, United States
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44
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Shiao R, Lee-Kubli CA. Neuropathic Pain After Spinal Cord Injury: Challenges and Research Perspectives. Neurotherapeutics 2018; 15:635-653. [PMID: 29736857 PMCID: PMC6095789 DOI: 10.1007/s13311-018-0633-4] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Neuropathic pain is a debilitating consequence of spinal cord injury (SCI) that remains difficult to treat because underlying mechanisms are not yet fully understood. In part, this is due to limitations of evaluating neuropathic pain in animal models in general, and SCI rodents in particular. Though pain in patients is primarily spontaneous, with relatively few patients experiencing evoked pains, animal models of SCI pain have primarily relied upon evoked withdrawals. Greater use of operant tasks for evaluation of the affective dimension of pain in rodents is needed, but these tests have their own limitations such that additional studies of the relationship between evoked withdrawals and operant outcomes are recommended. In preclinical SCI models, enhanced reflex withdrawal or pain responses can arise from pathological changes that occur at any point along the sensory neuraxis. Use of quantitative sensory testing for identification of optimal treatment approach may yield improved identification of treatment options and clinical trial design. Additionally, a better understanding of the differences between mechanisms contributing to at- versus below-level neuropathic pain and neuropathic pain versus spasticity may shed insights into novel treatment options. Finally, the role of patient characteristics such as age and sex in pathogenesis of neuropathic SCI pain remains to be addressed.
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Affiliation(s)
- Rani Shiao
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, 10010 N. Torrey Pines, La Jolla, California, 92073, USA
| | - Corinne A Lee-Kubli
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, 10010 N. Torrey Pines, La Jolla, California, 92073, USA.
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45
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Soluble TNFα Signaling within the Spinal Cord Contributes to the Development of Autonomic Dysreflexia and Ensuing Vascular and Immune Dysfunction after Spinal Cord Injury. J Neurosci 2018; 38:4146-4162. [PMID: 29610439 DOI: 10.1523/jneurosci.2376-17.2018] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 03/08/2018] [Accepted: 03/14/2018] [Indexed: 12/15/2022] Open
Abstract
Cardiovascular disease and susceptibility to infection are leading causes of morbidity and mortality for individuals with spinal cord injury (SCI). A major contributor to these is autonomic dysreflexia (AD), an amplified reaction of the autonomic nervous system (hallmarked by severe hypertension) in response to sensory stimuli below the injury. Maladaptive plasticity of the spinal sympathetic reflex circuit below the SCI results in AD intensification over time. Mechanisms underlying this maladaptive plasticity are poorly understood, restricting the identification of treatments. Thus, no preventative treatments are currently available. Neuroinflammation has been implicated in other pathologies associated with hyperexcitable neural circuits. Specifically, the soluble form of TNFα (sTNFα) is known to play a role in neuroplasticity. We hypothesize that persistent expression of sTNFα in spinal cord underlies AD exacerbation. To test this, we intrathecally administered XPro1595, a biologic that renders sTNFα nonfunctional, after complete, high-level SCI in female rats. This dramatically attenuated the intensification of colorectal distension-induced and naturally occurring AD events. This improvement is mediated via decreased sprouting of nociceptive primary afferents and activation of the spinal sympathetic reflex circuit. We also examined peripheral vascular function using ex vivo pressurized arterial preparations and immune function via flow cytometric analysis of splenocytes. Diminishing AD via pharmacological inhibition of sTNFα mitigated ensuing vascular hypersensitivity and immune dysfunction. This is the first demonstration that neuroinflammation-induced sTNFα is critical for altering the spinal sympathetic reflex circuit, elucidating a novel mechanism for AD. Importantly, we identify the first potential pharmacological, prophylactic treatment for this life-threatening syndrome.SIGNIFICANCE STATEMENT Autonomic dysreflexia (AD), a disorder that develops after spinal cord injury (SCI) and is hallmarked by sudden, extreme hypertension, contributes to cardiovascular disease and susceptibility to infection, respectively, two leading causes of mortality and morbidity in SCI patients. We demonstrate that neuroinflammation-induced expression of soluble TNFα plays a critical role in AD, elucidating a novel underlying mechanism. We found that intrathecal administration after SCI of a biologic that inhibits soluble TNFα signaling dramatically attenuates AD and significantly reduces AD-associated peripheral vascular and immune dysfunction. We identified mechanisms behind diminished plasticity of neuronal populations within the spinal sympathetic reflex circuit. This study is the first to pinpoint a potential pharmacological, prophylactic strategy to attenuate AD and ensuing cardiovascular and immune dysfunction.
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Wang Y, Feng C, He H, He J, Wang J, Li X, Wang S, Li W, Hou J, Liu T, Fang D, Xie SQ. Sensitization of TRPV1 receptors by TNF-α orchestrates the development of vincristine-induced pain. Oncol Lett 2018; 15:5013-5019. [PMID: 29552137 PMCID: PMC5840530 DOI: 10.3892/ol.2018.7986] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Accepted: 01/16/2018] [Indexed: 12/15/2022] Open
Abstract
Vincristine is one of the most common anticancer drugs clinically employed in the treatment of various malignancies. A major side effect associated with vincristine is the development of neuropathic pain, which is not readily relieved by available analgesics. Although efforts have been made to identify the pathogenesis of vincristine-induced neuropathic pain, the mechanisms underlying its pathogenesis have not been fully elucidated. In the present study, a neuropathic pain model was established in Sprague-Dawley rats by intraperitoneal injection of vincristine sulfate. The results demonstrated that vincristine administration induced the upregulation of transient receptor potential cation channel subfamily V member 1 (TRPV1) protein expression and current density in dorsal root ganglion (DRG) nociceptive neurons. Consistently, inhibition of TRPV1 with capsazepine alleviated vincristine-induced mechanical allodynia and thermal hyperalgesia in rats. Furthermore, vincristine administration induced the upregulation of tumor necrosis factor (TNF)-α production in DRGs, and inhibition of TNF-α synthesis with thalidomide in vivo reversed TRPV1 protein expression, as well as pain hypersensitivity induced by vincristine in rats. The present results suggested that TNF-α could sensitize TRPV1 by promoting its expression, thus leading to mechanical allodynia and thermal hyperalgesia in vincristine-treated rats. Taken together, these findings may enhance our understanding of the pathophysiological mechanisms underlying vincristine-induced pain.
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Affiliation(s)
- Ying Wang
- Department of Medical Imaging, The First Affiliated Hospital of Henan University, Kaifeng, Henan 475001, P.R. China
| | - Chenyang Feng
- Institute of Chemical Biology, College of Pharmacy, Henan University, Kaifeng, Henan 475004, P.R. China
| | - Haoying He
- Institute of Chemical Biology, College of Pharmacy, Henan University, Kaifeng, Henan 475004, P.R. China
| | - Jinjin He
- Department of Clinic Pharmacy, The First Affiliated Hospital of Henan University, Kaifeng, Henan 475001, P.R. China
| | - Jun Wang
- Institute of Chemical Biology, College of Pharmacy, Henan University, Kaifeng, Henan 475004, P.R. China
| | - Xiaomin Li
- Institute of Chemical Biology, College of Pharmacy, Henan University, Kaifeng, Henan 475004, P.R. China
| | - Shasha Wang
- Institute of Chemical Biology, College of Pharmacy, Henan University, Kaifeng, Henan 475004, P.R. China
| | - Wei Li
- Institute of Chemical Biology, College of Pharmacy, Henan University, Kaifeng, Henan 475004, P.R. China
| | - Jiuzhou Hou
- Institute of Chemical Biology, College of Pharmacy, Henan University, Kaifeng, Henan 475004, P.R. China
| | - Tong Liu
- Institute of Chemical Biology, College of Pharmacy, Henan University, Kaifeng, Henan 475004, P.R. China
| | - Dong Fang
- Institute of Chemical Biology, College of Pharmacy, Henan University, Kaifeng, Henan 475004, P.R. China
| | - Song-Qiang Xie
- Institute of Chemical Biology, College of Pharmacy, Henan University, Kaifeng, Henan 475004, P.R. China
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Ge A, Wang S, Miao B, Yan M. Effects of metformin on the expression of AMPK and STAT3 in the spinal dorsal horn of rats with neuropathic pain. Mol Med Rep 2018; 17:5229-5237. [PMID: 29393487 PMCID: PMC5865989 DOI: 10.3892/mmr.2018.8541] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 12/29/2017] [Indexed: 12/14/2022] Open
Abstract
Neuropathic pain (NP) is a frustrating and burdensome problem. Current treatments for NP have unendurable side effects and/or questionable efficacy, and once these therapies are stopped, the symptoms often return. Thus, novel drugs are needed to enhance the effectiveness of treatments for NP. One novel target for pain treatments is adenosine monophosphate-activated protein kinase (AMPK), which regulates a variety of cellular processes, including protein translation, which is considered to be affected in NP. Metformin is a widely available drug that possesses the ability to activate AMPK. The signal transducer and activator of transcription 3 (STAT3) pathway plays an important role in neuroinflammation. The present study investigated the analgesic effect of metformin on NP induced by chronic constriction injury (CCI), and the influence of metformin on the expression of AMPK and STAT3 in the spinal dorsal horn (SDH). In CCI rats, paw withdrawal latencies in response to thermal hyperalgesia were significantly shorter, while phosphorylated (p)-AMPK was expressed at lower levels and p-STAT3 was expressed at higher levels in the SDH. Administering intraperitoneal injections of metformin (200 mg/kg) for 6 successive days activated AMPK and suppressed the expression of p-STAT3, in addition to reversing hyperalgesia. Finally, metformin inhibited the activation of microglia and astrocytes in the SDH, which may explain how it alleviates NP.
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Affiliation(s)
- Anqi Ge
- Jiangsu Province Key Laboratory of Anesthesiology, Clinic Skill Center, Xuzhou Medical University, Xuzhou, Jiangsu 221000, P.R. China
| | - Shu Wang
- Department of Anesthesiology, The Third People's Hospital, Yancheng, Jiangsu 224001, P.R. China
| | - Bei Miao
- Laboratory of Gastroenterology, Xuzhou Medical University, Xuzhou, Jiangsu 221000, P.R. China
| | - Ming Yan
- Jiangsu Province Key Laboratory of Anesthesiology, Department of Anesthesiology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu 221000, P.R. China
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48
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Ruppert KA, Nguyen TT, Prabhakara KS, Toledano Furman NE, Srivastava AK, Harting MT, Cox CS, Olson SD. Human Mesenchymal Stromal Cell-Derived Extracellular Vesicles Modify Microglial Response and Improve Clinical Outcomes in Experimental Spinal Cord Injury. Sci Rep 2018; 8:480. [PMID: 29323194 PMCID: PMC5764957 DOI: 10.1038/s41598-017-18867-w] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 12/17/2017] [Indexed: 02/03/2023] Open
Abstract
No current clinical intervention can alter the course of acute spinal cord injury (SCI), or appreciably improve neurological outcome. Mesenchymal stromal cells (MSCs) have been shown to modulate the injury sequelae of SCI largely via paracrine effects, although the mechanisms remain incompletely understood. One potential modality is through secretion of extracellular vesicles (EVs). In this study, we investigate whether systemic administration of EVs isolated from human MSCs (MSCEv) has the potential to be efficacious as an alternative to cell-based therapy for SCI. Additionally, we investigate whether EVs isolated from human MSCs stimulated with pro-inflammatory cytokines have enhanced anti-inflammatory effects when administered after SCI. Immunohistochemistry supported the quantitative analysis, demonstrating a diminished inflammatory response with apparent astrocyte and microglia disorganization in cord tissue up to 10 mm caudal to the injury site. Locomotor recovery scores showed significant improvement among animals treated with MSCEv. Significant increases in mechanical sensitivity threshold were observed in animals treated with EVs from either naïve MSC (MSCEvwt) or stimulated MSC (MSCEv+), with a statistically significant increase in threshold for MSCEv+-treated animals when compared to those that received MSCEvwt. In conclusion, these data show that treatment of acute SCI with extracellular vesicles derived from human MSCs attenuates neuroinflammation and improves functional recovery.
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Affiliation(s)
- Katherine A Ruppert
- Department of Pediatric Surgery, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Tin T Nguyen
- Department of Pediatric Surgery, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Karthik S Prabhakara
- Department of Pediatric Surgery, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Naama E Toledano Furman
- Department of Pediatric Surgery, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Amit K Srivastava
- Department of Pediatric Surgery, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Matthew T Harting
- Department of Pediatric Surgery, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Charles S Cox
- Department of Pediatric Surgery, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Scott D Olson
- Department of Pediatric Surgery, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, TX, USA.
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49
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50
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Opposite, bidirectional shifts in excitation and inhibition in specific types of dorsal horn interneurons are associated with spasticity and pain post-SCI. Sci Rep 2017; 7:5884. [PMID: 28724992 PMCID: PMC5517549 DOI: 10.1038/s41598-017-06049-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 06/01/2017] [Indexed: 11/23/2022] Open
Abstract
Spasticity, a common complication after spinal cord injury (SCI), is frequently accompanied by chronic pain. The physiological origin of this pain (critical to its treatment) remains unknown, although spastic motor dysfunction has been related to the hyperexcitability of motoneurons and to changes in spinal sensory processing. Here we show that the pain mechanism involves changes in sensory circuits of the dorsal horn (DH) where nociceptive inputs integrate for pain processing. Spasticity is associated with the DH hyperexcitability resulting from an increase in excitation and disinhibition occurring in two respective types of sensory interneurons. In the tonic-firing inhibitory lamina II interneurons, glutamatergic drive was reduced while glycinergic inhibition was potentiated. In contrast, excitatory drive was boosted to the adapting-firing excitatory lamina II interneurons while GABAergic and glycinergic inhibition were reduced. Thus, increased activity of excitatory DH interneurons coupled with the reduced excitability of inhibitory DH interneurons post-SCI could provide a neurophysiological mechanism of central sensitization and chronic pain associated with spasticity.
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