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Delestrée N, Semizoglou E, Pagiazitis JG, Vukojicic A, Drobac E, Paushkin V, Mentis GZ. Serotonergic dysfunction impairs locomotor coordination in spinal muscular atrophy. Brain 2023; 146:4574-4593. [PMID: 37678880 PMCID: PMC10629775 DOI: 10.1093/brain/awad221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 05/12/2023] [Accepted: 06/11/2023] [Indexed: 09/09/2023] Open
Abstract
Neuromodulation by serotonin regulates the activity of neuronal networks responsible for a wide variety of essential behaviours. Serotonin (or 5-HT) typically activates metabotropic G protein-coupled receptors, which in turn initiate second messenger signalling cascades and induce short and long-lasting behavioural effects. Serotonin is intricately involved in the production of locomotor activity and gait control for different motor behaviours. Although dysfunction of serotonergic neurotransmission has been associated with mood disorders and spasticity after spinal cord injury, whether and to what extent such dysregulation is implicated in movement disorders has not been firmly established. Here, we investigated whether serotonergic neuromodulation is affected in spinal muscular atrophy (SMA), a neurodegenerative disease caused by ubiquitous deficiency of the SMN protein. The hallmarks of SMA are death of spinal motor neurons, muscle atrophy and impaired motor control, both in human patients and mouse models of disease. We used a severe mouse model of SMA, that closely recapitulates the severe symptoms exhibited by type I SMA patients, the most common and most severe form of the disease. Together, with mouse genetics, optogenetics, physiology, morphology and behavioural analysis, we report severe dysfunction of serotonergic neurotransmission in the spinal cord of SMA mice, both at early and late stages of the disease. This dysfunction is followed by reduction of 5-HT synapses on vulnerable motor neurons. We demonstrate that motor neurons innervating axial and trunk musculature are preferentially affected, suggesting a possible cause for the proximo-distal progression of disease, and raising the possibility that it may underlie scoliosis in SMA patients. We also demonstrate that the 5-HT dysfunction is caused by SMN deficiency in serotonergic neurons in the raphe nuclei of the brainstem. The behavioural significance of the dysfunction in serotonergic neuromodulation is underlined by inter-limb discoordination in SMA mice, which is ameliorated when selective restoration of SMN in 5-HT neurons is achieved by genetic means. Our study uncovers an unexpected dysfunction of serotonergic neuromodulation in SMA and indicates that, if normal function is to be restored under disease conditions, 5-HT neuromodulation should be a key target for therapeutic approaches.
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Affiliation(s)
- Nicolas Delestrée
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA
- Department of Neurology, Columbia University, New York, NY 10032, USA
| | - Evangelia Semizoglou
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA
- Department of Neurology, Columbia University, New York, NY 10032, USA
| | - John G Pagiazitis
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA
- Department of Neurology, Columbia University, New York, NY 10032, USA
| | - Aleksandra Vukojicic
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA
- Department of Neurology, Columbia University, New York, NY 10032, USA
| | - Estelle Drobac
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
| | - Vasilissa Paushkin
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA
- Department of Neurology, Columbia University, New York, NY 10032, USA
| | - George Z Mentis
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA
- Department of Neurology, Columbia University, New York, NY 10032, USA
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
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2
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Davaa G, Hong JY, Lee JH, Kim MS, Buitrago JO, Li YM, Lee HH, Han DW, Leong KW, Hyun JK, Kim HW. Delivery of Induced Neural Stem Cells Through Mechano-Tuned Silk-Collagen Hydrogels for the Recovery of Contused Spinal Cord in Rats. Adv Healthc Mater 2023; 12:e2201720. [PMID: 36447307 DOI: 10.1002/adhm.202201720] [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: 07/12/2022] [Revised: 09/16/2022] [Indexed: 12/02/2022]
Abstract
Neural stem cells (NSC) have tremendous potential for therapeutic regeneration of diseased or traumatized neural tissues, including injured spinal cord. However, transplanted NSC suffer from low cell survival and uncontrolled differentiation, limiting in vivo efficacy. Here, this issue is tackled by delivery through silk-collagen protein hydrogels that are stiffness-matched, stress-relaxing, and shear-thinning. The mechanically-tuned hydrogels protect NSC reprogrammed from fibroblasts (iNSC) initially from injection shear-stress, and enhance long-term survival over 12 weeks. Hydrogel-iNSC treatment alleviates neural inflammation, with reduced inflammatory cells and lesions than NSC-only. The iNSC migrate from the hydrogel into surrounding tissues, secrete up-regulated neurotrophic factors, and differentiate into neural cell subtypes, forming synapses. More serotonergic axons are observed in the lesion cavity, and locomotor functions are improved in hydrogel-iNSC than in iNSC-only. This study highlights the ability of mechanically-tuned protein hydrogels to protect iNSC from the injection stress and severe inflammatory environment, allowing them to differentiate and function to recover the injured spinal cord.
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Affiliation(s)
- Ganchimeg Davaa
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, 31116, Republic of Korea.,Department of Nanobiomedical Science and BK21 NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan, 31116, Republic of Korea
| | - Jin Young Hong
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, 31116, Republic of Korea.,Department of Nanobiomedical Science and BK21 NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan, 31116, Republic of Korea
| | - Jung-Hwan Lee
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, 31116, Republic of Korea.,Department of Nanobiomedical Science and BK21 NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan, 31116, Republic of Korea.,Department of Biomaterials Science, School of Dentistry, Dankook University, Cheonan, 31116, Republic of Korea.,Cell & Matter Institute, Dankook University, Cheonan, 31116, Republic of Korea.,UCL Eastman-Korea Dental Medicine Innovation Centre, Dankook University, Cheonan, 31116, Republic of Korea.,Mechanobiology Dental Medicine Research Center, Dankook University, Cheonan, 31116, Republic of Korea
| | - Min Soo Kim
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, 31116, Republic of Korea.,Department of Nanobiomedical Science and BK21 NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan, 31116, Republic of Korea
| | - Jennifer O Buitrago
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, 31116, Republic of Korea.,Department of Nanobiomedical Science and BK21 NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan, 31116, Republic of Korea.,Basic Sciences Department, International University of Catalonia (UIC), Barcelona, 08017, Spain
| | - Yu-Meng Li
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, 31116, Republic of Korea.,Department of Nanobiomedical Science and BK21 NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan, 31116, Republic of Korea
| | - Hae-Hyoung Lee
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, 31116, Republic of Korea.,Department of Nanobiomedical Science and BK21 NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan, 31116, Republic of Korea.,Department of Biomaterials Science, School of Dentistry, Dankook University, Cheonan, 31116, Republic of Korea.,Cell & Matter Institute, Dankook University, Cheonan, 31116, Republic of Korea
| | - Dong Wook Han
- Konkuk University Open-Innovation Center, Institute of Biomedical Science & Technology, Konkuk University, Seoul, 143701, Republic of Korea
| | - Kam W Leong
- Department of Nanobiomedical Science and BK21 NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan, 31116, Republic of Korea.,Department of Biomedical Engineering, Columbia University, New York, NY, 10027, USA.,Department of Systems Biology, Columbia University Medical Center, New York, NY, 10032, USA
| | - Jung Keun Hyun
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, 31116, Republic of Korea.,Department of Nanobiomedical Science and BK21 NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan, 31116, Republic of Korea.,Department of Rehabilitation Medicine, College of Medicine, Dankook University, Cheonan, 31116, Republic of Korea.,Wiregene Co., Ltd., Cheonan, 31116, Republic of Korea
| | - Hae-Won Kim
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, 31116, Republic of Korea.,Department of Nanobiomedical Science and BK21 NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan, 31116, Republic of Korea.,Department of Biomaterials Science, School of Dentistry, Dankook University, Cheonan, 31116, Republic of Korea.,Cell & Matter Institute, Dankook University, Cheonan, 31116, Republic of Korea.,UCL Eastman-Korea Dental Medicine Innovation Centre, Dankook University, Cheonan, 31116, Republic of Korea.,Mechanobiology Dental Medicine Research Center, Dankook University, Cheonan, 31116, Republic of Korea
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3
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Quan X, Yu C, Fan Z, Wu T, Qi C, Zhang H, Wu S, Wang X. Hydralazine plays an immunomodulation role of pro-regeneration in a mouse model of spinal cord injury. Exp Neurol 2023; 363:114367. [PMID: 36858281 DOI: 10.1016/j.expneurol.2023.114367] [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: 08/30/2022] [Revised: 02/09/2023] [Accepted: 02/24/2023] [Indexed: 03/02/2023]
Abstract
Spinal cord injury (SCI) results in severe motor and sensory dysfunction with no effective therapy. Spinal cord debris (sp) from injured spinal cord evokes secondary SCI continuously. We and other researchers have previously clarified that it is mainly bone marrow derived macrophages (BMDMs) infiltrating in the lesion epicenter to clear sp, rather than local microglia. Unfortunately, the pro-inflammatory phenotype of these infiltrating BMDMs is predominant which impairs wound healing. Hydralazine, as a potent vasodilator and scavenger of acrolein, has protective effects in many diseases. Hydralazine is also confirmed to promote motor function and hypersensitivity in SCI rats through scavenging acrolein. However, few studies have explored the effects of hydralazine on immunomodulation, as well as spontaneous pain and emotional response, the important syndromes in clinical patients. It remains unclear whether hydralazine affects infiltrating BMDMs after SCI. In this study, we targeted BMDMs to explore the influence of hydralazine on immune cells in a mouse model of SCI, and also investigated the contribution of polarized BMDMs to hydralazine-induced neurological function recovery after SCI in male mice. The adult male mice underwent T10 spinal cord compression. The results showed that in addition to improving motor function and hypersensitivity, hydralazine relieved SCI-induced spontaneous pain and emotional response, which is a newly discovered function of hydralazine. Hydralazine inhibited the recruitments of pro-inflammatory BMDMs and educated infiltrated BMDMs to a more reparative phenotype involving in multiple biological processes associated with SCI pathology, including immune/inflammation response, neurogenesis, lipid metabolism, oxidative stress, fibrosis formation, and angiogenesis, etc. As an overall effect, hydralazine-treated BMDMs loaden with sp partially rescued neurological function after SCI. It is concluded that hydralazine plays an immunomodulation role of educating pro-inflammatory BMDMs to a more reparative phenotype; and hydralazine-educated BMDMs contribute to hydralazine-induced improvement of neurological function in SCI mice, which provides support for drug and cell treatment options for SCI therapy.
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Affiliation(s)
- Xin Quan
- Institute of Neurosciences and Department of Neurobiology, Fourth Military Medical University, Xi'an 710032, China
| | - Caiyong Yu
- Institute of Neurosciences and Department of Neurobiology, Fourth Military Medical University, Xi'an 710032, China; Military Medical Innovation Center, Fourth Military Medical University, Xi'an 710032, China
| | - Zhongmin Fan
- Department of Critical Care Medicine and Department of Anesthesiology and Perioprative Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China
| | - Tong Wu
- Institute of Neurosciences and Department of Neurobiology, Fourth Military Medical University, Xi'an 710032, China
| | - Chuchu Qi
- Institute of Neurosciences and Department of Neurobiology, Fourth Military Medical University, Xi'an 710032, China
| | - Haoying Zhang
- Institute of Neurosciences and Department of Neurobiology, Fourth Military Medical University, Xi'an 710032, China
| | - Shengxi Wu
- Institute of Neurosciences and Department of Neurobiology, Fourth Military Medical University, Xi'an 710032, China.
| | - Xi Wang
- Institute of Neurosciences and Department of Neurobiology, Fourth Military Medical University, Xi'an 710032, China; The College of Life Sciences and Medicine, Northwest University, Xi'an 710069, China.
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4
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Benedetti B, Weidenhammer A, Reisinger M, Couillard-Despres S. Spinal Cord Injury and Loss of Cortical Inhibition. Int J Mol Sci 2022; 23:5622. [PMID: 35628434 PMCID: PMC9144195 DOI: 10.3390/ijms23105622] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 05/09/2022] [Accepted: 05/13/2022] [Indexed: 02/04/2023] Open
Abstract
After spinal cord injury (SCI), the destruction of spinal parenchyma causes permanent deficits in motor functions, which correlates with the severity and location of the lesion. Despite being disconnected from their targets, most cortical motor neurons survive the acute phase of SCI, and these neurons can therefore be a resource for functional recovery, provided that they are properly reconnected and retuned to a physiological state. However, inappropriate re-integration of cortical neurons or aberrant activity of corticospinal networks may worsen the long-term outcomes of SCI. In this review, we revisit recent studies addressing the relation between cortical disinhibition and functional recovery after SCI. Evidence suggests that cortical disinhibition can be either beneficial or detrimental in a context-dependent manner. A careful examination of clinical data helps to resolve apparent paradoxes and explain the heterogeneity of treatment outcomes. Additionally, evidence gained from SCI animal models indicates probable mechanisms mediating cortical disinhibition. Understanding the mechanisms and dynamics of cortical disinhibition is a prerequisite to improve current interventions through targeted pharmacological and/or rehabilitative interventions following SCI.
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Affiliation(s)
- Bruno Benedetti
- Institute of Experimental Neuroregeneration, Paracelsus Medical University, 5020 Salzburg, Austria; (B.B.); (A.W.); (M.R.)
- Spinal Cord Injury and Tissue Regeneration Center Salzburg (SCI-TReCS), 5020 Salzburg, Austria
- Austrian Cluster for Tissue Regeneration, 1200 Vienna, Austria
| | - Annika Weidenhammer
- Institute of Experimental Neuroregeneration, Paracelsus Medical University, 5020 Salzburg, Austria; (B.B.); (A.W.); (M.R.)
- Spinal Cord Injury and Tissue Regeneration Center Salzburg (SCI-TReCS), 5020 Salzburg, Austria
| | - Maximilian Reisinger
- Institute of Experimental Neuroregeneration, Paracelsus Medical University, 5020 Salzburg, Austria; (B.B.); (A.W.); (M.R.)
- Spinal Cord Injury and Tissue Regeneration Center Salzburg (SCI-TReCS), 5020 Salzburg, Austria
| | - Sebastien Couillard-Despres
- Institute of Experimental Neuroregeneration, Paracelsus Medical University, 5020 Salzburg, Austria; (B.B.); (A.W.); (M.R.)
- Spinal Cord Injury and Tissue Regeneration Center Salzburg (SCI-TReCS), 5020 Salzburg, Austria
- Austrian Cluster for Tissue Regeneration, 1200 Vienna, Austria
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5
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Wong ML, Widerstrom-Noga E, Field-Fote EC. Effects of whole-body vibration on neuropathic pain and the relationship between pain and spasticity in persons with spinal cord injury. Spinal Cord 2022; 60:963-970. [PMID: 35468994 DOI: 10.1038/s41393-022-00806-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 04/13/2022] [Accepted: 04/14/2022] [Indexed: 11/09/2022]
Abstract
OBJECTIVE Whole-body vibration (WBV) appears to modulate reflex hyperexcitability and spasticity. Due to common underlying neural mechanisms between spasticity and neuropathic pain, WBV may also reduce chronic pain after spinal cord injury (SCI). Our objective was to determine whether there are dose-related changes in pain following WBV and to examine the relationships between neuropathic pain and reflex excitability. STUDY DESIGN Secondary analysis of a sub-population (participants with neuropathic pain, n = 16) from a larger trial comparing the effects of two different doses of WBV on spasticity in persons with SCI. SETTING Hospital/Rehabilitation Center in Atlanta, GA, USA. METHODS Participants were randomized to 8-bout or 16-bout WBV groups. Both groups received ten sessions of sham intervention, followed by ten sessions of WBV. Primary measures included the Neuropathic Pain Symptom Inventory (NPSI) for pain symptom severity and H-reflex paired-pulse depression (PPD) for reflex excitability. RESULTS Mean change in NPSI scores were not significantly different between the groups (7 ± 6; p = 0.29; ES = 0.57); however, 8-bouts of WBV were consistently beneficial for participants with high neuropathic pain symptom severity (NPSI total score >30), while 16-bouts of WBV appeared to increase pain in some individuals with high NPSI scores. A baseline NPSI cut score of 30 predicted PPD response (sensitivity = 1.0, specificity = 0.83), with higher NPSI scores associated with decreased PPD in response to WBV. CONCLUSIONS WBV in moderate doses appears to decrease neuropathic pain symptoms and improve reflex modulation. However, at higher doses neuropathic pain symptoms may be aggravated. Lower baseline NPSI scores were associated with improved reflex modulation.
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Affiliation(s)
- Marlon L Wong
- Miami Project to Cure Paralysis, Miller School of Medicine, University of Miami, Miami, FL, USA. .,Department of Physical Therapy, Miller School of Medicine, University of Miami, Miami, FL, USA.
| | - Eva Widerstrom-Noga
- Miami Project to Cure Paralysis, Miller School of Medicine, University of Miami, Miami, FL, USA.,Neuroscience Graduate Program, University of Miami Miller School of Medicine, Miami, FL, USA.,Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Edelle C Field-Fote
- Shepherd Center, Crawford Research Institute, Atlanta, GA, USA.,Emory University School of Medicine, Division of Physical Therapy, Atlanta, GA, USA.,Georgia Institute of Technology, School of Biological Sciences, Atlanta, GA, USA
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6
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Wang S, Wang P, Yin R, Xiao M, Zhang Y, Reinhardt JD, Wang H, Xu G. Combination of repetitive transcranial magnetic stimulation and treadmill training reduces hyperreflexia by rebalancing motoneuron excitability in rats after spinal cord contusion. Neurosci Lett 2022; 775:136536. [PMID: 35183693 DOI: 10.1016/j.neulet.2022.136536] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 02/12/2022] [Accepted: 02/15/2022] [Indexed: 11/19/2022]
Abstract
Spasticity commonly emerges during the process of recovery after spinal cord injury (SCI) and critically exacerbates motor dysfunction. Given insufficient effects of individual therapies, we combined repetitive transcranial magnetic stimulation (rTMS) with treadmill training (Tr) in rats with SCI to investigate potential synergistic effects on alleviating spasticity and motor dysfunction. Animals were randomized into four groups: SCI only, rTMS, Tr, and rTMS plus Tr. At the study endpoint eight weeks after the start of interventions, the rTMS plus Tr group exhibited the largest decrease in maximal H-reflex amplitude/maximal M-wave amplitude ratio (effect size (ES): -0.082, 95% confidence interval (CI): -0.118 to -0.046, p < 0.001) as well as the greatest improvement in motor function measured with the Basso, Beattie, and Bresnahan locomotor scale (ES: 1.811, 95% CI: 1.018 to 2.603, p < 0.001; significantly different from all other groups at p < 0.01) and grid-walking test (ES: -5.1, 95% CI: -7.784 to -2.416, p < 0.001, significantly different from rTMS alone at p < 0.01). Pathological analyses demonstrated that the combined treatment facilitated the growth of serotonergic axons around the lesion site, and the upregulation of 5-hydroxytryptamine, potassium-chloride cotransporter-2, and glutamic acid decarboxylases 67 in the lumbar spinal cord distal to the injury site. All effects of combined treatment of rTMS and treadmill training were enhanced compared to treadmill training or rTMS alone. Treadmill training and rTMS intervention appear to have synergistic effects on hyperreflexia and locomotion likely related to a restored balance between facilitatory and inhibitory inputs to motoneurons.
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Affiliation(s)
- Shuangyan Wang
- Department of Rehabilitation Medicine, Zhongda Hospital, Southeast University Nanjing 210024, China; Nanjing Medical University, Center of Rehabilitation Medicine, 1st affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
| | - Pei Wang
- Department of Rehabilitation Medicine, Zhongda Hospital, Southeast University Nanjing 210024, China
| | - Ruian Yin
- Department of Rehabilitation Medicine, Zhongda Hospital, Southeast University Nanjing 210024, China
| | - Ming Xiao
- Jiangsu Key Laboratory of Neurodegeneration, Nanjing Medical University, Nanjing 211166, China
| | - Yongjie Zhang
- Department of Human Anatomy, Nanjing Medical University, Nanjing 211166, China
| | - Jan D Reinhardt
- Institute for Disaster Management and Reconstruction, Sichuan University, Chengdu, China
| | - Hongxing Wang
- Department of Rehabilitation Medicine, Zhongda Hospital, Southeast University Nanjing 210024, China.
| | - Guangxu Xu
- Nanjing Medical University, Center of Rehabilitation Medicine, 1st affiliated Hospital of Nanjing Medical University, Nanjing 210029, China.
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7
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Fauss GNK, Hudson KE, Grau JW. Role of Descending Serotonergic Fibers in the Development of Pathophysiology after Spinal Cord Injury (SCI): Contribution to Chronic Pain, Spasticity, and Autonomic Dysreflexia. BIOLOGY 2022; 11:234. [PMID: 35205100 PMCID: PMC8869318 DOI: 10.3390/biology11020234] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 01/27/2022] [Accepted: 01/29/2022] [Indexed: 12/12/2022]
Abstract
As the nervous system develops, nerve fibers from the brain form descending tracts that regulate the execution of motor behavior within the spinal cord, incoming sensory signals, and capacity to change (plasticity). How these fibers affect function depends upon the transmitter released, the receptor system engaged, and the pattern of neural innervation. The current review focuses upon the neurotransmitter serotonin (5-HT) and its capacity to dampen (inhibit) neural excitation. A brief review of key anatomical details, receptor types, and pharmacology is provided. The paper then considers how damage to descending serotonergic fibers contributes to pathophysiology after spinal cord injury (SCI). The loss of serotonergic fibers removes an inhibitory brake that enables plasticity and neural excitation. In this state, noxious stimulation can induce a form of over-excitation that sensitizes pain (nociceptive) circuits, a modification that can contribute to the development of chronic pain. Over time, the loss of serotonergic fibers allows prolonged motor drive (spasticity) to develop and removes a regulatory brake on autonomic function, which enables bouts of unregulated sympathetic activity (autonomic dysreflexia). Recent research has shown that the loss of descending serotonergic activity is accompanied by a shift in how the neurotransmitter GABA affects neural activity, reducing its inhibitory effect. Treatments that target the loss of inhibition could have therapeutic benefit.
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Affiliation(s)
| | | | - James W. Grau
- Department of Psychological and Brain Sciences, Texas A&M University, College Station, TX 77843, USA; (G.N.K.F.); (K.E.H.)
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Moriya S, Yamashita A, Masukawa D, Sakaguchi J, Ikoma Y, Sameshima Y, Kambe Y, Yamanaka A, Kuwaki T. Involvement of A5/A7 noradrenergic neurons and B2 serotonergic neurons in nociceptive processing: a fiber photometry study. Neural Regen Res 2021; 17:881-886. [PMID: 34472489 PMCID: PMC8530127 DOI: 10.4103/1673-5374.322465] [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] [Indexed: 11/26/2022] Open
Abstract
In the central nervous system, the A6 noradrenaline (NA) and the B3 serotonin (5-HT) cell groups are well-recognized players in the descending antinociceptive system, while other NA/5-HT cell groups are not well characterized. A5/A7 NA and B2 5-HT cells project to the spinal horn and form descending pathways. We recorded G-CaMP6 green fluorescence signal intensities in the A5/A7 NA and the B2 5-HT cell groups of awake mice in response to acute tail pinch stimuli, acute heat stimuli, and in the context of a non-noxious control test, using fiber photometry with a calcium imaging system. We first introduced G-CaMP6 in the A5/A7 NA or B2 5-HT neuronal soma, using transgenic mice carrying the tetracycline-controlled transactivator transgene under the control of either a dopamine β-hydroxylase or a tryptophan hydroxylase-2 promoters and by the site-specific injection of adeno-associated virus (AAV-TetO(3G)-G-CaMP6). After confirming the specific expression patterns of G-CaMP6, we recorded G-CaMP6 green fluorescence signals in these sites in awake mice in response to acute nociceptive stimuli. G-CaMP6 fluorescence intensity in the A5, A7, and B2 cell groups was rapidly increased in response to acute nociceptive stimuli and soon after, it returned to baseline fluorescence intensity. This was not observed in the non-noxious control test. The results indicate that acute nociceptive stimuli rapidly increase the activities of A5/A7 NA or B2 5-HT neurons but the non-noxious stimuli do not. The present study suggests that A5/A7 NA or B2 5-HT neurons play important roles in nociceptive processing in the central nervous system. We suggest that A5/A7/B2 neurons may be new therapeutic targets. All performed procedures were approved by the Institutional Animal Use Committee of Kagoshima University (MD17105) on February 22, 2018.
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Affiliation(s)
- Shunpei Moriya
- Department of Physiology, Kagoshima University Graduate School of Medical and Dental Science, Kagoshima, Japan
| | - Akira Yamashita
- Department of Physiology, Kagoshima University Graduate School of Medical and Dental Science, Kagoshima, Japan
| | - Daiki Masukawa
- Department of Molecular Pharmacology and Neurobiology, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Junichi Sakaguchi
- Department of Physiology, Kagoshima University Graduate School of Medical and Dental Science, Kagoshima, Japan
| | - Yoko Ikoma
- Department of Physiology, Kagoshima University Graduate School of Medical and Dental Science, Kagoshima, Japan
| | - Yoshimune Sameshima
- Department of Pharmacology, Kagoshima University Graduate School of Medical and Dental Science, Kagoshima, Japan
| | - Yuki Kambe
- Department of Pharmacology, Kagoshima University Graduate School of Medical and Dental Science, Kagoshima, Japan
| | - Akihiro Yamanaka
- Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan
| | - Tomoyuki Kuwaki
- Department of Physiology, Kagoshima University Graduate School of Medical and Dental Science, Kagoshima, Japan
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9
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Early escitalopram administration as a preemptive treatment strategy against spasticity after contusive spinal cord injury in rats. Sci Rep 2021; 11:7120. [PMID: 33782426 PMCID: PMC8007832 DOI: 10.1038/s41598-021-85961-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 02/23/2021] [Indexed: 11/29/2022] Open
Abstract
In the majority of spinal cord injury (SCI) patients, spasticity develops in the subacute phase and chronically persists with muscle hypertonia. Among various pathological conditions underlying spasticity, upregulated expression of 5-HT receptors (5-HTR) on the spinal motor neurons due to 5-HT denervation is considered one of crucial factors for hyperexcitability of the spinal circuit. As a 5-HT signal modulator, selective serotonin re-uptake inhibitors (SSRIs) are ordinarily prescribed for diseases associated with 5-HT in the CNS, and are known for their ability to increase 5-HT levels as well as to desensitize 5-HTR. Here, we hypothesized that early SSRI administration as a preemptive treatment strategy would effectively prevent the onset of spasticity. We used a rat model of contusive SCI and administered escitalopram during the first 4 weeks after injury, which is the period required for spasticity development in rodent models. We performed a swimming test to quantify spastic behaviors and conducted the Hoffman reflex test as well as histological analyses for 5-HT2AR and KCC2 expressions. Four weeks of escitalopram administration suppressed spastic behaviors during the swimming test and reduced the population of spasticity-strong rats. Moreover, the treatment resulted in decreased immunoreactivity of 5-HT2AR in the spinal motor neurons. Result of the H-reflex test and membrane expression of KCC2 were not significantly altered. In summary, early escitalopram administration could prevent the onset of spastic behaviors via regulation of 5-HT system after SCI, but could not modulate exaggerated spinal reflex. Our results suggest a novel application of SSRIs for preventative treatment of spasticity.
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Rodriguez-Jimenez FJ, Vilches A, Perez-Arago MA, Clemente E, Roman R, Leal J, Castro AA, Fustero S, Moreno-Manzano V, Jendelova P, Stojkovic M, Erceg S. Activation of Neurogenesis in Multipotent Stem Cells Cultured In Vitro and in the Spinal Cord Tissue After Severe Injury by Inhibition of Glycogen Synthase Kinase-3. Neurotherapeutics 2021; 18:515-533. [PMID: 33000422 PMCID: PMC8116371 DOI: 10.1007/s13311-020-00928-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/01/2020] [Indexed: 12/24/2022] Open
Abstract
The inhibition of glycogen synthase kinase-3 (GSK-3) can induce neurogenesis, and the associated activation of Wnt/β-catenin signaling via GSK-3 inhibition may represent a means to promote motor function recovery following spinal cord injury (SCI) via increased astrocyte migration, reduced astrocyte apoptosis, and enhanced axonal growth. Herein, we assessed the effects of GSK-3 inhibition in vitro on the neurogenesis of ependymal stem/progenitor cells (epSPCs) resident in the mouse spinal cord and of human embryonic stem cell-derived neural progenitors (hESC-NPs) and human-induced pluripotent stem cell-derived neural progenitors (hiPSC-NPs) and in vivo on spinal cord tissue regeneration and motor activity after SCI. We report that the treatment of epSPCs and human pluripotent stem cell-derived neural progenitors (hPSC-NPs) with the GSK-3 inhibitor Ro3303544 activates β-catenin signaling and increases the expression of the bIII-tubulin neuronal marker; furthermore, the differentiation of Ro3303544-treated cells prompted an increase in the number of terminally differentiated neurons. Administration of a water-soluble, bioavailable form of this GSK-3 inhibitor (Ro3303544-Cl) in a severe SCI mouse model revealed the increased expression of bIII-tubulin in the injury epicenter. Treatment with Ro3303544-Cl increased survival of mature neuron types from the propriospinal tract (vGlut1, Parv) and raphe tract (5-HT), protein kinase C gamma-positive neurons, and GABAergic interneurons (GAD65/67) above the injury epicenter. Moreover, we observed higher numbers of newly born BrdU/DCX-positive neurons in Ro3303544-Cl-treated animal tissues, a reduced area delimited by astrocyte scar borders, and improved motor function. Based on this study, we believe that treating animals with epSPCs or hPSC-NPs in combination with Ro3303544-Cl deserves further investigation towards the development of a possible therapeutic strategy for SCI.
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Affiliation(s)
| | - Angel Vilches
- Stem Cell Therapies in Neurodegenerative Diseases Lab, Research Center "Principe Felipe", C/ Eduardo Primo Yufera 3, Valencia, Spain
| | - Maria Amparo Perez-Arago
- National Stem Cell Bank-Valencia Node, Biomolecular Resources Platform PRB3, ISCIII, Research Center "Principe Felipe", C/ Eduardo Primo Yúfera 3, 46012, Valencia, Spain
| | - Eleonora Clemente
- Stem Cell Therapies in Neurodegenerative Diseases Lab, Research Center "Principe Felipe", C/ Eduardo Primo Yufera 3, Valencia, Spain
| | - Raquel Roman
- Organic Molecules Lab, Research Center "Principe Felipe", C/ Eduardo Primo Yufera 3, 46012, Valencia, Spain
- Department of Organic Chemistry, University of Valencia, 46100, Burjassot, Spain
| | - Juliette Leal
- Stem Cell Therapies in Neurodegenerative Diseases Lab, Research Center "Principe Felipe", C/ Eduardo Primo Yufera 3, Valencia, Spain
| | - Ana Artero Castro
- Stem Cell Therapies in Neurodegenerative Diseases Lab, Research Center "Principe Felipe", C/ Eduardo Primo Yufera 3, Valencia, Spain
| | - Santos Fustero
- Organic Molecules Lab, Research Center "Principe Felipe", C/ Eduardo Primo Yufera 3, 46012, Valencia, Spain
- Department of Organic Chemistry, University of Valencia, 46100, Burjassot, Spain
| | - Victoria Moreno-Manzano
- Neuronal and Tissue Regeneration Lab, Research Center "Principe Felipe", C/ Eduardo Primo Yufera 3, 46012, Valencia, Spain
| | - Pavla Jendelova
- Institute of Experimental Medicine, Department of Neuroregeneration, Czech Academy of Sciences, Prague, Czech Republic
| | - Miodrag Stojkovic
- Department of Human Genetics, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
- Eaton Peabody Laboratories, Department of Otolaryngology, Massachusetts Eye and Ear, Boston, MA, USA
- Department of Otolaryngology-Head and Neck Surgery, Harvard Medical School, Boston, MA, USA
| | - Slaven Erceg
- Stem Cell Therapies in Neurodegenerative Diseases Lab, Research Center "Principe Felipe", C/ Eduardo Primo Yufera 3, Valencia, Spain.
- National Stem Cell Bank-Valencia Node, Biomolecular Resources Platform PRB3, ISCIII, Research Center "Principe Felipe", C/ Eduardo Primo Yúfera 3, 46012, Valencia, Spain.
- Institute of Experimental Medicine, Department of Neuroregeneration, Czech Academy of Sciences, Prague, Czech Republic.
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Afshari K, Dehdashtian A, Haddad NS, Jazaeri SZ, Ursu DC, Khalilzadeh M, Haj-Mirzaian A, Shakiba S, Burns TC, Tavangar SM, Ghasemi M, Dehpour AR. Sumatriptan improves the locomotor activity and neuropathic pain by modulating neuroinflammation in rat model of spinal cord injury. Neurol Res 2020; 43:29-39. [PMID: 32935647 DOI: 10.1080/01616412.2020.1819090] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
OBJECTIVES To investigate the therapeutic effects of sumatriptan in a rat model of spinal cord injury (SCI) and possible anti-inflammatory and analgesic mechanisms underlying this effect. METHODS Using an aneurysm mini-clip model of contusive SCI, T9-10 laminectomies were performed for 60 male rats. Animals were divided into six experimental groups (n = 10 per group) as follows: a minocycline administered positive control group, a saline-vehicle negative control group, a sham-operated group, and three experimental groups which received separate doses of sumatriptan (0.1, 0.3 and 1 mg/kg). Behavioural assessments were used to evaluate locomotor activity and neuropathic pain for 28 days. At the end of the study, spinal cord tissues were collected from sacrificed animals for histopathological analysis. Levels of calcitonin gene-related peptide (CGRP) and two pro-inflammatory cytokines (tumor necrosis factor [TNF]-α and interleukin [IL]-1β) were assessed by the enzyme-linked immunosorbent assay (ELISA). RESULTS Sumatriptan significantly (P < 0.001) improved the locomotor activity in SCI group. Sumatriptan was also more effective than the positive control, i.e. minocycline (0.3 mg/kg). Additionally, sumatriptan and minocycline similarly attenuated the mechanical and thermal allodynia in SCI (P < 0.001). TNF-α, IL-1β and CGRP levels in sumatriptan- and minocycline-treated groups significantly (P < 0.001) decreased compared to controls. Histopathological analysis also revealed a markedly improvement in hemorrhage followed by inflammatory cell invasion, neuronal vacuolation, and cyst formation in both sumatriptan- and minocycline-treated groups compared to control animals. CONCLUSIONS Sumatriptan improves functional recovery from SCI through its anti-inflammatory effects and reducing pro-inflammatory and pain mediators.
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Affiliation(s)
- Khashayar Afshari
- Experimental Medicine Research Center, Tehran University of Medical Sciences , Tehran, Iran.,Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences , Tehran, Iran
| | - Amir Dehdashtian
- Experimental Medicine Research Center, Tehran University of Medical Sciences , Tehran, Iran.,Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences , Tehran, Iran
| | - Nazgol-Sadat Haddad
- Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences , Tehran, Iran
| | | | - Daniel C Ursu
- Department of Surgery, Section of Plastic and Reconstructive Surgery, University of Michigan , USA
| | - Mina Khalilzadeh
- Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences , Tehran, Iran
| | - Arvin Haj-Mirzaian
- Experimental Medicine Research Center, Tehran University of Medical Sciences , Tehran, Iran.,Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences , Tehran, Iran
| | - Saeed Shakiba
- Experimental Medicine Research Center, Tehran University of Medical Sciences , Tehran, Iran.,Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences , Tehran, Iran
| | - Terry C Burns
- Department of Neurological Surgery, Mayo Clinic Rochester , USA
| | - Seyed Mohammad Tavangar
- Chronic Diseases Research Center, Endocrinology and Metabolism Population Sciences Institute, Tehran University of Medical Sciences , Tehran, Iran.,Department of Pathology, Dr. Shariati Hospital, Tehran University of Medical Sciences , Tehran, Iran
| | - Mehdi Ghasemi
- Department of Neurology, University of Massachusetts School of Medicine , Worcester, MA
| | - Ahmad Reza Dehpour
- Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences , Tehran, Iran.,Department of Pharmacology, Faculty of Medicine, Tehran University of Medical Sciences , Tehran, Iran
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Zhu Y, Cheng J, Yin J, Yang Y, Guo J, Zhang W, Xie B, Lu H, Hao D. Effects of sacral nerve electrical stimulation on 5‑HT and 5‑HT3AR/5‑HT4R levels in the colon and sacral cord of acute spinal cord injury rat models. Mol Med Rep 2020; 22:763-773. [PMID: 32626986 PMCID: PMC7339713 DOI: 10.3892/mmr.2020.11148] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 10/31/2019] [Indexed: 12/13/2022] Open
Abstract
Spinal cord injury (SCI) often leads to defecation dysfunction. Sacral nerve electrical stimulation (SNS) therapy could improve defecation function. The present study aimed to assess SNS therapy, with regard to the levels of serotonin (5-HT) and its receptors (5-HT3AR and 5-HT4R) in the colon and sacral cord, a rat model of acute severe SCI was used. This rat model was made using the New York University Impactor device. Model rats were randomized to the SCI and SNS (electrical stimulation on the S3 nerve) groups. After 14 days of treatment, enteric transmission function was assessed. 5-HT and 5-HT3AR/5-HT4R were measured by ELISA, quantitative PCR, immunohistochemistry and western blotting. In SCI rats, SNS significantly increased the quantity of feces, shortened the time to the first fecal passage, and improved fecal texture and colon histology. SNS elevated 5-HT contents in the colon and spinal cord, and enhanced 5-HT3AR/5-HT4R protein expression and distribution in the colonic myenteric plexus and mucosa, sacral intermediolateral nucleus and dorsal horn. SNS upregulated the relative expression levels of 5-HT3AR/5-HT4R mRNA and protein in the colon and spinal cord. SNS can improve defecation and accelerate the recovery of colonic transmission functions in rat models of acute SCI. These effects involved upregulation of the 5-HT/5-HT3AR/5-HT4R axes.
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Affiliation(s)
- Yi Zhu
- Department of Spine Surgery, Honghui Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710054, P.R. China
| | - Jie Cheng
- College of Acupuncture and Tuina, Nanjing University of Chinese Medicine, Nanjing, Jiangsu 210023, P.R. China
| | - Jichao Yin
- Department of Orthopaedics and Traumatology, Xi'an Hospital of Traditional Chinese Medicine, Xi'an, Shaanxi 710000, P.R. China
| | - Yujie Yang
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong, SAR 999077, P.R. China
| | - Jiabao Guo
- Department of Sport Rehabilitation, Shanghai University of Sport, Shanghai 200438, P.R. China
| | - Wenyi Zhang
- Rehabilitation Medicine Center, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210000, P.R. China
| | - Bing Xie
- Department of Orthopedics and Traumatology, Jiangyin Orthopedics Hospital of Traditional Chinese Medicine, Jiangyin, Jiangsu 214400, P.R. China
| | - Haixia Lu
- Institute of Neurobiology, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, P.R. China
| | - Dingjun Hao
- Department of Spine Surgery, Honghui Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710054, P.R. China
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Selective Upregulation by Theanine of Slc38a1 Expression in Neural Stem Cell for Brain Wellness. Molecules 2020; 25:molecules25020347. [PMID: 31952134 PMCID: PMC7024158 DOI: 10.3390/molecules25020347] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 01/09/2020] [Accepted: 01/15/2020] [Indexed: 12/22/2022] Open
Abstract
Theanine is an amino acid abundant in green tea with an amide moiety analogous to glutamine (GLN) rather than glutamic acid (Glu) and GABA, which are both well-known as amino acid neurotransmitters in the brain. Theanine has no polyphenol and flavonoid structures required for an anti-oxidative property as seen with catechins and tannins, which are more enriched in green tea. We have shown marked inhibition by this exogenous amino acid theanine of the uptake of [3H]GLN, but not of [3H]Glu, in rat brain synaptosomes. Beside a ubiquitous role as an endogenous amino acid, GLN has been believed to be a main precursor for the neurotransmitter Glu sequestered in a neurotransmitter pool at glutamatergic neurons in the brain. The GLN transporter solute carrier 38a1 (Slc38a1) plays a crucial role in the incorporation of extracellular GLN for the intracellular conversion to Glu by glutaminase and subsequent sequestration at synaptic vesicles in neurons. However, Slc38a1 is also expressed by undifferentiated neural progenitor cells (NPCs) not featuring a neuronal phenotype. NPCs are derived from a primitive stem cell endowed to proliferate for self-renewal and to commit differentiation to several daughter cell lineages such as neurons, astrocytes, and oligodendrocytes. In vitro culture with theanine leads to the marked promotion of the generation of new neurons together with selective upregulation of Slc38a1 transcript expression in NPCs. In this review, we will refer to a possible novel neurogenic role of theanine for brain wellness through a molecular mechanism relevant to facilitated neurogenesis with a focus on Slc38a1 expressed by undifferentiated NPCs on the basis of our accumulating findings to date.
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14
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Seira O, Liu J, Assinck P, Ramer M, Tetzlaff W. KIF2A characterization after spinal cord injury. Cell Mol Life Sci 2019; 76:4355-4368. [PMID: 31041455 PMCID: PMC11105463 DOI: 10.1007/s00018-019-03116-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 04/05/2019] [Accepted: 04/24/2019] [Indexed: 01/23/2023]
Abstract
Axons in the central nervous system (CNS) typically fail to regenerate after injury. This failure is multi-factorial and caused in part by disruption of the axonal cytoskeleton. The cytoskeleton, in particular microtubules (MT), plays a critical role in axonal transport and axon growth during development. In this regard, members of the kinesin superfamily of proteins (KIFs) regulate the extension of primary axons toward their targets and control the growth of collateral branches. KIF2A negatively regulates axon growth through MT depolymerization. Using three different injury models to induce SCI in adult rats, we examined the temporal and cellular expression of KIF2A in the injured spinal cord. We observed a progressive increase of KIF2A expression with maximal levels at 10 days to 8 weeks post-injury as determined by Western blot analysis. KIF2A immunoreactivity was present in axons, spinal neurons and mature oligodendrocytes adjacent to the injury site. Results from the present study suggest that KIF2A at the injured axonal tips may contribute to neurite outgrowth inhibition after injury, and that its increased expression in inhibitory spinal neurons adjacent to the injury site might contribute to an intrinsic wiring-control mechanism associated with neuropathic pain. Further studies will determine whether KIF2A may be a potential target for the development of regeneration-promoting or pain-preventing therapies.
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Affiliation(s)
- Oscar Seira
- International Collaboration on Repair Discoveries (ICORD), Blusson Spinal Cord Centre, University of British Columbia (UBC), 818 West 10th Avenue, Vancouver, BC, V5Z 1M9, Canada.
- Department of Zoology, University of British Columbia (UBC), Vancouver, Canada.
| | - Jie Liu
- International Collaboration on Repair Discoveries (ICORD), Blusson Spinal Cord Centre, University of British Columbia (UBC), 818 West 10th Avenue, Vancouver, BC, V5Z 1M9, Canada
| | - Peggy Assinck
- International Collaboration on Repair Discoveries (ICORD), Blusson Spinal Cord Centre, University of British Columbia (UBC), 818 West 10th Avenue, Vancouver, BC, V5Z 1M9, Canada
- Graduate Program in Neuroscience, University of British Columbia (UBC), Vancouver, Canada
- MRC Centre for Regenerative Medicine, The University of Edinburgh, Edinburgh, UK
| | - Matt Ramer
- International Collaboration on Repair Discoveries (ICORD), Blusson Spinal Cord Centre, University of British Columbia (UBC), 818 West 10th Avenue, Vancouver, BC, V5Z 1M9, Canada
- Department of Zoology, University of British Columbia (UBC), Vancouver, Canada
| | - Wolfram Tetzlaff
- International Collaboration on Repair Discoveries (ICORD), Blusson Spinal Cord Centre, University of British Columbia (UBC), 818 West 10th Avenue, Vancouver, BC, V5Z 1M9, Canada
- Department of Zoology, University of British Columbia (UBC), Vancouver, Canada
- Department of Surgery, University of British Columbia (UBC), Vancouver, Canada
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15
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Perrin FE, Noristani HN. Serotonergic mechanisms in spinal cord injury. Exp Neurol 2019; 318:174-191. [PMID: 31085200 DOI: 10.1016/j.expneurol.2019.05.007] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 05/07/2019] [Accepted: 05/08/2019] [Indexed: 12/12/2022]
Abstract
Spinal cord injury (SCI) is a tragic event causing irreversible losses of sensory, motor, and autonomic functions, that may also be associated with chronic neuropathic pain. Serotonin (5-HT) neurotransmission in the spinal cord is critical for modulating sensory, motor, and autonomic functions. Following SCI, 5-HT axons caudal to the lesion site degenerate, and the degree of axonal degeneration positively correlates with lesion severity. Rostral to the lesion, 5-HT axons sprout, irrespective of the severity of the injury. Unlike callosal fibers and cholinergic projections, 5-HT axons are more resistant to an inhibitory milieu and undergo active sprouting and regeneration after central nervous system (CNS) traumatism. Numerous studies suggest that a chronic increase in serotonergic neurotransmission promotes 5-HT axon sprouting in the intact CNS. Moreover, recent studies in invertebrates suggest that 5-HT has a pro-regenerative role in injured axons. Here we present a brief description of 5-HT discovery, 5-HT innervation of the CNS, and physiological functions of 5-HT in the spinal cord, including its role in controlling bladder function. We then present a comprehensive overview of changes in serotonergic axons after CNS damage, and discuss their plasticity upon altered 5-HT neurotransmitter levels. Subsequently, we provide an in-depth review of therapeutic approaches targeting 5-HT neurotransmission, as well as other pre-clinical strategies to promote an increase in re-growth of 5-HT axons, and their functional consequences in SCI animal models. Finally, we highlight recent findings signifying the direct role of 5-HT in axon regeneration and suggest strategies to further promote robust long-distance re-growth of 5-HT axons across the lesion site and eventually achieve functional recovery following SCI.
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Affiliation(s)
- Florence Evelyne Perrin
- University of Montpellier, Montpellier, F-34095 France; INSERM, U1198, Montpellier, F-34095 France; EPHE, Paris, F-75014 France
| | - Harun Najib Noristani
- Shriners Hospitals Pediatric Research Center, Center for Neural Repair, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA; Department of Anatomy and Cell Biology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA.
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Svensson E, Apergis-Schoute J, Burnstock G, Nusbaum MP, Parker D, Schiöth HB. General Principles of Neuronal Co-transmission: Insights From Multiple Model Systems. Front Neural Circuits 2019; 12:117. [PMID: 30728768 PMCID: PMC6352749 DOI: 10.3389/fncir.2018.00117] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 12/14/2018] [Indexed: 12/22/2022] Open
Abstract
It is now accepted that neurons contain and release multiple transmitter substances. However, we still have only limited insight into the regulation and functional effects of this co-transmission. Given that there are 200 or more neurotransmitters, the chemical complexity of the nervous system is daunting. This is made more-so by the fact that their interacting effects can generate diverse non-linear and novel consequences. The relatively poor history of pharmacological approaches likely reflects the fact that manipulating a transmitter system will not necessarily mimic its roles within the normal chemical environment of the nervous system (e.g., when it acts in parallel with co-transmitters). In this article, co-transmission is discussed in a range of systems [from invertebrate and lower vertebrate models, up to the mammalian peripheral and central nervous system (CNS)] to highlight approaches used, degree of understanding, and open questions and future directions. Finally, we offer some outlines of what we consider to be the general principles of co-transmission, as well as what we think are the most pressing general aspects that need to be addressed to move forward in our understanding of co-transmission.
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Affiliation(s)
- Erik Svensson
- BMC, Department of Neuroscience, Functional Pharmacology, Uppsala University, Uppsala, Sweden
| | - John Apergis-Schoute
- Department of Neurosciences, Psychology and Behaviour, University of Leicester, Leicester, United Kingdom
| | - Geoffrey Burnstock
- Department of Pharmacology and Therapeutics, University of Melbourne, Melbourne, VIC, Australia
| | - Michael P Nusbaum
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - David Parker
- Department of Physiology, Development and Neuroscience, Faculty of Biology, University of Cambridge, Cambridge, United Kingdom
| | - Helgi B Schiöth
- BMC, Department of Neuroscience, Functional Pharmacology, Uppsala University, Uppsala, Sweden.,Institute for Translational Medicine and Biotechnology, Sechenov First Moscow State Medical University, Moscow, Russia
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Sharma HS, Feng L, Muresanu DF, Castellani RJ, Sharma A. Neuroprotective effects of a potent bradykinin B2 receptor antagonist HOE-140 on microvascular permeability, blood flow disturbances, edema formation, cell injury and nitric oxide synthase upregulation following trauma to the spinal cord. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2019; 146:103-152. [DOI: 10.1016/bs.irn.2019.06.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Huang YJ, Grau JW. Ionic plasticity and pain: The loss of descending serotonergic fibers after spinal cord injury transforms how GABA affects pain. Exp Neurol 2018; 306:105-116. [PMID: 29729247 PMCID: PMC5994379 DOI: 10.1016/j.expneurol.2018.05.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 04/24/2018] [Accepted: 05/01/2018] [Indexed: 12/14/2022]
Abstract
Activation of pain (nociceptive) fibers can sensitize neural circuits within the spinal cord, inducing an increase in excitability (central sensitization) that can foster chronic pain. The development of spinally-mediated central sensitization is regulated by descending fibers and GABAergic interneurons. In adult animals, the co-transporter KCC2 maintains a low intracellular concentration of the anion Cl-. As a result, when the GABA-A receptor is engaged, Cl- flows in the neuron which has a hyperpolarizing (inhibitory) effect. Spinal cord injury (SCI) can down-regulate KCC2 and reverse the flow of Cl-. Under these conditions, engaging the GABA-A receptor can have a depolarizing (excitatory) effect that fosters the development of nociceptive sensitization. The present paper explores how SCI alters GABA function and provides evidence that the loss of descending fibers alters pain transmission to the brain. Prior work has shown that, after SCI, administration of a GABA-A antagonist blocks the development of capsaicin-induced nociceptive sensitization, implying that GABA release plays an essential role. This excitatory effect is linked to serotonergic (5HT) fibers that descend through the dorsolateral funiculus (DLF) and impact spinal function via the 5HT-1A receptor. Supporting this, blocking the 5HT-1A receptor, or lesioning the DLF, emulated the effect of SCI. Conversely, spinal application of a 5HT-1A agonist up-regulated KCC2 and reversed the effect of bicuculline treatment. Finally, lesioning the DLF reversed how a GABA-A antagonist affects a capsaicin-induced aversion in a place conditioning task; in sham operated animals, bicuculline enhanced aversion whereas in DLF-lesioned rats biciculline had an antinociceptive effect.
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Affiliation(s)
- Yung-Jen Huang
- Behavioral and Cellular Neuroscience, Department of Psychology, Texas A&M University, College Station, TX 77843, USA.
| | - James W Grau
- Behavioral and Cellular Neuroscience, Department of Psychology, Texas A&M University, College Station, TX 77843, USA
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McKay WB, Sweatman WM, Field-Fote EC. The experience of spasticity after spinal cord injury: perceived characteristics and impact on daily life. Spinal Cord 2018; 56:478-486. [DOI: 10.1038/s41393-017-0038-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 11/09/2017] [Accepted: 11/11/2017] [Indexed: 11/09/2022]
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Spinal Cord Hemisection Facilitates Aromatic L-Amino Acid Decarboxylase Cells to Produce Serotonin in the Subchronic but Not the Chronic Phase. Neural Plast 2015; 2015:549671. [PMID: 26504602 PMCID: PMC4609486 DOI: 10.1155/2015/549671] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Revised: 05/12/2015] [Accepted: 05/19/2015] [Indexed: 11/18/2022] Open
Abstract
Neuromodulators, such as serotonin (5-hydroxytryptamine, 5-HT) and noradrenalin, play an essential role in regulating the motor and sensory functions in the spinal cord. We have previously shown that in the rat spinal cord the activity of aromatic L-amino acid decarboxylase (AADC) cells to produce 5-HT from its precursor (5-hydroxytryptophan, 5-HTP) is dramatically increased following complete spinal cord transection. In this study, we investigated whether a partial loss of 5-HT innervation could similarly increase AADC activity. Adult rats with spinal cord hemisected at thoracic level (T11/T12) were used with a postoperation interval at 5 days or 60 days. Using immunohistochemistry, first, we observed a significant reduction in the density of 5-HT-immunoreactive fibers in the spinal cord below the lesion on the injured side for both groups. Second, we found that the AADC cells were similarly expressed on both injured and uninjured sides in both groups. Third, increased production of 5-HT in AADC cells following 5-HTP was seen in 5-day but not in 60-day postinjury group. These results suggest that plastic changes of the 5-HT system might happen primarily in the subchronic phase and for longer period its function could be compensated by plastic changes of other intrinsic and/or supraspinal modulation systems.
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Ghosh M, Pearse DD. The role of the serotonergic system in locomotor recovery after spinal cord injury. Front Neural Circuits 2015; 8:151. [PMID: 25709569 PMCID: PMC4321350 DOI: 10.3389/fncir.2014.00151] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Accepted: 12/28/2014] [Indexed: 11/30/2022] Open
Abstract
Serotonin (5-HT), a monoamine neurotransmitter synthesized in various populations of brainstem neurons, plays an important role in modulating the activity of spinal networks involved in vertebrate locomotion. Following spinal cord injury (SCI) there is a disruption of descending serotonergic projections to spinal motor areas, which results in a subsequent depletion in 5-HT, the dysregulation of 5-HT transporters as well as the elevated expression, super-sensitivity and/or constitutive auto-activation of specific 5-HT receptors. These changes in the serotonergic system can produce varying degrees of locomotor dysfunction through to paralysis. To date, various approaches targeting the different components of the serotonergic system have been employed to restore limb coordination and improve locomotor function in experimental models of SCI. These strategies have included pharmacological modulation of serotonergic receptors, through the administration of specific 5-HT receptor agonists, or by elevating the 5-HT precursor 5-hydroxytryptophan, which produces a global activation of all classes of 5-HT receptors. Stimulation of these receptors leads to the activation of the locomotor central pattern generator (CPG) below the site of injury to facilitate or improve the quality and frequency of movements, particularly when used in concert with the activation of other monoaminergic systems or coupled with electrical stimulation. Another approach has been to employ cell therapeutics to replace the loss of descending serotonergic input to the CPG, either through transplanted fetal brainstem 5-HT neurons at the site of injury that can supply 5-HT to below the level of the lesion or by other cell types to provide a substrate at the injury site for encouraging serotonergic axon regrowth across the lesion to the caudal spinal cord for restoring locomotion.
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Affiliation(s)
- Mousumi Ghosh
- The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine Miami, FL, USA ; Department of Neurological Surgery, University of Miami Miller School of Medicine Miami, FL, USA
| | - Damien D Pearse
- The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine Miami, FL, USA ; Department of Neurological Surgery, University of Miami Miller School of Medicine Miami, FL, USA ; The Neuroscience Program, University of Miami Miller School of Medicine Miami, FL, USA ; The Interdisciplinary Stem Cell Institute, University of Miami Miller School of Medicine Miami, FL, USA
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Geremia NM, Bao F, Rosenzweig TE, Hryciw T, Weaver L, Dekaban GA, Brown A. CD11d Antibody Treatment Improves Recovery in Spinal Cord-Injured Mice. J Neurotrauma 2011; 29:539-50. [PMID: 22044160 DOI: 10.1089/neu.2011.1976] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Acute administration of a monoclonal antibody (mAb) raised against the CD11d subunit of the leukocyte CD11d/CD18 integrin after spinal cord injury (SCI) in the rat greatly improves neurological outcomes. This has been chiefly attributed to the reduced infiltration of neutrophils into the injured spinal cord in treated rats. More recently, treating spinal cord-injured mice with a Ly-6G neutrophil-depleting antibody was demonstrated to impair neurological recovery. These disparate results could be due to different mechanisms of action utilized by the two antibodies, or due to differences in the inflammatory responses between mouse and rat that are triggered by SCI. To address whether the anti-CD11d treatment would be effective in mice, a CD11d mAb (205C) or a control mAb (1B7) was administered intravenously at 2, 24, and 48 h after an 8-g clip compression injury at the fourth thoracic spinal segment. The anti-CD11d treatment reduced neutrophil infiltration into the injured mouse spinal cord and was associated with increased white matter sparing and reductions in myeloperoxidase (MPO) activity, reactive oxygen species, lipid peroxidation, and scar formation. These improvements in the injured spinal cord microenvironment were accompanied by increased serotonin (5-HT) immunoreactivity below the level of the lesion and improved locomotor recovery. Our results with the 205C CD11d mAb treatment complement previous work using this anti-integrin treatment in a rat model of SCI.
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Affiliation(s)
- Nicole M Geremia
- The Spinal Cord Injury Team, Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada.
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