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Bartzokis G. Neuroglialpharmacology: myelination as a shared mechanism of action of psychotropic treatments. Neuropharmacology 2012; 62:2137-53. [PMID: 22306524 PMCID: PMC3586811 DOI: 10.1016/j.neuropharm.2012.01.015] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Revised: 01/18/2012] [Accepted: 01/19/2012] [Indexed: 12/20/2022]
Abstract
Current psychiatric diagnostic schema segregate symptom clusters into discrete entities, however, large proportions of patients suffer from comorbid conditions that fit neither diagnostic nor therapeutic schema. Similarly, psychotropic treatments ranging from lithium and antipsychotics to serotonin reuptake inhibitors (SSRIs) and acetylcholinesterase inhibitors have been shown to be efficacious in a wide spectrum of psychiatric disorders ranging from autism, schizophrenia (SZ), depression, and bipolar disorder (BD) to Alzheimer's disease (AD). This apparent lack of specificity suggests that psychiatric symptoms as well as treatments may share aspects of pathophysiology and mechanisms of action that defy current symptom-based diagnostic and neuron-based therapeutic schema. A myelin-centered model of human brain function can help integrate these incongruities and provide novel insights into disease etiologies and treatment mechanisms. Available data are integrated herein to suggest that widely used psychotropic treatments ranging from antipsychotics and antidepressants to lithium and electroconvulsive therapy share complex signaling pathways such as Akt and glycogen synthase kinase-3 (GSK3) that affect myelination, its plasticity, and repair. These signaling pathways respond to neurotransmitters, neurotrophins, hormones, and nutrition, underlie intricate neuroglial communications, and may substantially contribute to the mechanisms of action and wide spectra of efficacy of current therapeutics by promoting myelination. Imaging and genetic technologies make it possible to safely and non-invasively test these hypotheses directly in humans and can help guide clinical trial efforts designed to correct myelination abnormalities. Such efforts may provide insights into novel avenues for treatment and prevention of some of the most prevalent and devastating human diseases.
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Affiliation(s)
- George Bartzokis
- Department of Psychiatry, The David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.
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RhoA-inhibiting NSAIDs promote axonal myelination after spinal cord injury. Exp Neurol 2011; 231:247-60. [PMID: 21781963 DOI: 10.1016/j.expneurol.2011.06.018] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Revised: 06/07/2011] [Accepted: 06/30/2011] [Indexed: 12/19/2022]
Abstract
Nonsteroidal anti-inflammatory drugs (NSAIDs) are extensively used to relieve pain and inflammation in humans via cyclooxygenase inhibition. Our recent research suggests that certain NSAIDs including ibuprofen suppress intracellular RhoA signal and improve significant axonal growth and functional recovery following axonal injury in the CNS. Several NSAIDs have been shown to reduce generation of amyloid-beta42 peptide via inactivation of RhoA signal, supporting potent RhoA-repressing function of selected NSAIDs. In this report, we demonstrate that RhoA-inhibiting NSAIDs ibuprofen and indomethacin dramatically reduce cell death of oligodendrocytes in cultures or along the white matter tracts in rats with a spinal cord injury. More importantly, we demonstrate that treatments with the RhoA-inhibiting NSAIDs significantly increase axonal myelination along the white matter tracts following a traumatic contusion spinal cord injury. In contrast, non-RhoA-inhibiting NSAID naproxen does not have such an effect. Thus, our results suggest that RhoA inactivation with certain NSAIDs benefits recovery of injured CNS axons not only by promoting axonal elongation, but by enhancing glial survival and axonal myelination along the disrupted axonal tracts. This study, together with previous reports, supports that RhoA signal is an important therapeutic target for promoting recovery of injured CNS and that RhoA-inhibiting NSAIDs provide great therapeutic potential for CNS axonal injuries in adult mammals.
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Saiwai H, Ohkawa Y, Yamada H, Kumamaru H, Harada A, Okano H, Yokomizo T, Iwamoto Y, Okada S. The LTB4-BLT1 axis mediates neutrophil infiltration and secondary injury in experimental spinal cord injury. THE AMERICAN JOURNAL OF PATHOLOGY 2010; 176:2352-66. [PMID: 20304963 DOI: 10.2353/ajpath.2010.090839] [Citation(s) in RCA: 136] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Traumatic injury in the central nervous system induces inflammation; however, the role of this inflammation is controversial. Precise analysis of the inflammatory cells is important to gain a better understanding of the inflammatory machinery in response to neural injury. Here, we demonstrated that leukotriene B4 plays a significant role in mediating leukocyte infiltration after spinal cord injury. Using flow cytometry, we revealed that neutrophil and monocyte/macrophage infiltration peaked 12 hours after injury and was significantly suppressed in leukotriene B4 receptor 1 knockout mice. Similar findings were observed in mice treated with a leukotriene B4 receptor antagonist. Further, by isolating each inflammatory cell subset with a cell sorter, and performing quantitative reverse transcription-PCR, we demonstrated the individual contributions of more highly expressed subsets, ie, interleukins 6 and 1beta, tumor necrosis factor-alpha, and FasL, to the inflammatory reaction and neural apoptosis. Inhibition of leukotriene B4 suppressed leukocyte infiltration after injury, thereby attenuating the inflammatory reaction, sparing the white matter, and reducing neural apoptosis, as well as inducing better functional recovery. These findings are the first to demonstrate that leukotriene B4 is involved in the pathogenesis of spinal cord injury through the amplification of leukocyte infiltration, and provide a potential therapeutic strategy for traumatic spinal cord injury.
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Affiliation(s)
- Hirokazu Saiwai
- Department of Research Superstar Program Stem Cell Unit, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
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Oh MJ, Seo TB, Kwon KB, Yoon SJ, Elzi DJ, Kim BG, Namgung U. Axonal Outgrowth and Erk1/2 Activation by Training after Spinal Cord Injury in Rats. J Neurotrauma 2009; 26:2071-82. [DOI: 10.1089/neu.2008.0800] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Affiliation(s)
- Myung-Jin Oh
- Department of Oriental Medicine, Daejeon University, Daejeon, Korea
| | - Tae Beom Seo
- Department of Oriental Medicine, Daejeon University, Daejeon, Korea
| | - Ku-Birm Kwon
- Department of Oriental Medicine, Daejeon University, Daejeon, Korea
| | - Sung-Jin Yoon
- Department of Physical Education, Korea University, Seoul, Korea
| | - David J. Elzi
- Children's Cancer Research Institute, The University of Texas Health Science Center, San Antonio, Texas
| | - Byung G. Kim
- Brain Disease Research Center, Institute for Medical Sciences, Ajou University School of Medicine, Suwon, Korea
| | - Uk Namgung
- Department of Oriental Medicine, Daejeon University, Daejeon, Korea
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Wu B, Ren X. Promoting Axonal Myelination for Improving Neurological Recovery in Spinal Cord Injury. J Neurotrauma 2009; 26:1847-56. [PMID: 19785544 DOI: 10.1089/neu.2008.0551] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Affiliation(s)
- Bo Wu
- Department of Orthopedics, Xinqiao Hospital, The Third Military Medical University, Chongqing, China
- Department of Orthopedics, 88th Hospital, Taian, Shangdong, China
| | - Xianjun Ren
- Department of Orthopedics, Xinqiao Hospital, The Third Military Medical University, Chongqing, China
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Targeting post-mitochondrial effectors of apoptosis for neuroprotection. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2009; 1787:402-13. [DOI: 10.1016/j.bbabio.2008.09.006] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2008] [Revised: 09/12/2008] [Accepted: 09/16/2008] [Indexed: 01/10/2023]
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Kang CE, Poon PC, Tator CH, Shoichet MS. A New Paradigm for Local and Sustained Release of Therapeutic Molecules to the Injured Spinal Cord for Neuroprotection and Tissue Repair. Tissue Eng Part A 2009; 15:595-604. [DOI: 10.1089/ten.tea.2007.0349] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
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Syed YA, Baer AS, Lubec G, Hoeger H, Widhalm G, Kotter MR. Inhibition of oligodendrocyte precursor cell differentiation by myelin-associated proteins. Neurosurg Focus 2008; 24:E5. [DOI: 10.3171/foc/2008/24/3-4/e4] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Object
Promoting repair of central nervous system (CNS) white matter represents an important approach to easing the course of a number of tragic neurological diseases. For this purpose, strategies are currently being evaluated for transplanting cells capable of generating new oligodendrocytes into areas of demyelination and/or enhancing the potential of endogenous stem/precursor cells to give rise to new oligodendrocytes. Emerging evidence, however, indicates that increasing the presence of cells capable of forming new myelin sheaths is not sufficient to promote repair because of unknown inhibitors that accumulate in lesions as a consequence of myelin degeneration and impair the generation of new oligodendrocytes. The aim of the present study was to characterize the nature of the inhibitory molecules present in myelin.
Methods
Differentiation of primary rat oligodendrocyte precursor cells (OPCs) in the presence of CNS and peripheral nervous system myelin was assessed by immunocytochemical methods. The authors further characterized the nature of the inhibitors by submitting myelin membrane preparations to biochemical precipitation and digestion. Finally, OPCs were grown on purified Nogo-A, oligodendrocyte myelin glycoprotein, and myelin-associated glycoprotein, the most prominent inhibitors of axon regeneration.
Results
Myelin membrane preparations induced a differentiation block in OPCs that was associated with down-regulation of expression of the transcription factor Nkx2.2. The inhibitory activity in myelin was restricted to the CNS and was predominantly associated with white matter. Furthermore, the results demonstrate that myelin proteins that are distinct from the most prominent inhibitors of axon outgrowth are specific inhibitors of OPC differentiation.
Conclusions
The inhibitory effect of unknown myelin-associated proteins should be considered in future treatment strategies aimed at enhancing CNS repair.
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Affiliation(s)
| | | | | | - Harald Hoeger
- 3Core Unit for Biomedical Research in Neurosurgery, Medical University of Vienna, Austria
| | | | - Mark R. Kotter
- 2Neurosurgery and
- 4Department of Neurosurgery, Karl-August University, Göttingen, Germany
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Kitamura K, Iwanami A, Nakamura M, Yamane J, Watanabe K, Suzuki Y, Miyazawa D, Shibata S, Funakoshi H, Miyatake S, Coffin RS, Nakamura T, Toyama Y, Okano H. Hepatocyte growth factor promotes endogenous repair and functional recovery after spinal cord injury. J Neurosci Res 2007; 85:2332-42. [PMID: 17549731 DOI: 10.1002/jnr.21372] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Many therapeutic interventions using neurotrophic factors or pharmacological agents have focused on secondary degeneration after spinal cord injury (SCI) to reduce damaged areas and promote axonal regeneration and functional recovery. Hepatocyte growth factor (HGF), which was identified as a potent mitogen for mature hepatocytes and a mediator of inflammatory responses to tissue injury, has recently been highlighted as a potent neurotrophic and angiogenic factor in the central nervous system (CNS). In the present study, we revealed that the extent of endogenous HGF up-regulation was less than that of c-Met, an HGF receptor, during the acute phase of SCI and administered exogenous HGF into injured spinal cord using a replication-incompetent herpes simplex virous-1 (HSV-1) vector to determine whether HGF exerts beneficial effects and promotes functional recovery after SCI. This treatment resulted in the significant promotion of neuron and oligodendrocyte survival, angiogenesis, axonal regrowth, and functional recovery after SCI. These results suggest that HGF gene delivery to the injured spinal cord exerts multiple beneficial effects and enhances endogenous repair after SCI. This is the first study to demonstrate the efficacy of HGF for SCI.
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Affiliation(s)
- Kazuya Kitamura
- Department of Orthopaedic Surgery, Keio University School of Medicine, Shinjuku, Tokyo, Japan
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