1
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Goodus MT, Alfredo AN, Carson KE, Dey P, Pukos N, Schwab JM, Popovich PG, Gao J, Mo X, Bruno RS, McTigue DM. Spinal cord injury-induced metabolic impairment and steatohepatitis develops in non-obese rats and is exacerbated by premorbid obesity. Exp Neurol 2024; 379:114847. [PMID: 38852834 DOI: 10.1016/j.expneurol.2024.114847] [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: 02/03/2024] [Revised: 05/27/2024] [Accepted: 06/06/2024] [Indexed: 06/11/2024]
Abstract
Impaired sensorimotor functions are prominent complications of spinal cord injury (SCI). A clinically important but less obvious consequence is development of metabolic syndrome (MetS), including increased adiposity, hyperglycemia/insulin resistance, and hyperlipidemia. MetS predisposes SCI individuals to earlier and more severe diabetes and cardiovascular disease compared to the general population, which trigger life-threatening complications (e.g., stroke, myocardial infarcts). Although each comorbidity is known to be a risk factor for diabetes and other health problems in obese individuals, their relative contribution or perceived importance in propagating systemic pathology after SCI has received less attention. This could be explained by an incomplete understanding of MetS promoted by SCI compared with that from the canonical trigger diet-induced obesity (DIO). Thus, here we compared metabolic-related outcomes after SCI in lean rats to those of uninjured rats with DIO. Surprisingly, SCI-induced MetS features were equal to or greater than those in obese uninjured rats, including insulin resistance, endotoxemia, hyperlipidemia, liver inflammation and steatosis. Considering the endemic nature of obesity, we also evaluated the effect of premorbid obesity in rats receiving SCI; the combination of DIO + SCI exacerbated MetS and liver pathology compared to either alone, suggesting that obese individuals that sustain a SCI are especially vulnerable to metabolic dysfunction. Notably, premorbid obesity also exacerbated intraspinal lesion pathology and worsened locomotor recovery after SCI. Overall, these results highlight that normal metabolic function requires intact spinal circuitry and that SCI is not just a sensory-motor disorder, but also has significant metabolic consequences.
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Affiliation(s)
- Matthew T Goodus
- The Belford Center for Spinal Cord Injury, College of Medicine, The Ohio State University, Columbus, OH 43210, USA; Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - Anthony N Alfredo
- Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, OH 43210, USA; Neuroscience Graduate Program, The Ohio State University, Columbus, OH 43210, USA
| | - Kaitlin E Carson
- The Belford Center for Spinal Cord Injury, College of Medicine, The Ohio State University, Columbus, OH 43210, USA; Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - Priyankar Dey
- Department of Biotechnology, Thapar Institute of Engineering and Technology, Patiala, Punjab, India
| | - Nicole Pukos
- The Belford Center for Spinal Cord Injury, College of Medicine, The Ohio State University, Columbus, OH 43210, USA; Neuroscience Graduate Program, The Ohio State University, Columbus, OH 43210, USA
| | - Jan M Schwab
- The Belford Center for Spinal Cord Injury, College of Medicine, The Ohio State University, Columbus, OH 43210, USA; Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, OH 43210, USA; Department of Neurology, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Phillip G Popovich
- The Belford Center for Spinal Cord Injury, College of Medicine, The Ohio State University, Columbus, OH 43210, USA; Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - Jie Gao
- Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - Xiaokui Mo
- Department of Biomedical Informatics, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Richard S Bruno
- Human Nutrition Program, College of Education and Human Ecology, The Ohio State University, Columbus, OH, USA
| | - Dana M McTigue
- The Belford Center for Spinal Cord Injury, College of Medicine, The Ohio State University, Columbus, OH 43210, USA; Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, OH 43210, USA.
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Liu H, Yi J, Zhang C, Li Y, Wang Q, Wang S, Dai S, Zheng Z, Jiang T, Gao P, Xue A, Huang Z, Kong F, Wang Y, He B, Guo X, Li Q, Chen J, Yin G, Zhao S. Macrophage GIT1 promotes oligodendrocyte precursor cell differentiation and remyelination after spinal cord injury. Glia 2024; 72:1674-1692. [PMID: 38899731 DOI: 10.1002/glia.24577] [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: 08/29/2023] [Revised: 05/02/2024] [Accepted: 05/27/2024] [Indexed: 06/21/2024]
Abstract
Spinal cord injury (SCI) can result in severe motor and sensory deficits, for which currently no effective cure exists. The pathological process underlying this injury is extremely complex and involves many cell types in the central nervous system. In this study, we have uncovered a novel function for macrophage G protein-coupled receptor kinase-interactor 1 (GIT1) in promoting remyelination and functional repair after SCI. Using GIT1flox/flox Lyz2-Cre (GIT1 CKO) mice, we identified that GIT1 deficiency in macrophages led to an increased generation of tumor necrosis factor-alpha (TNFα), reduced proportion of mature oligodendrocytes (mOLs), impaired remyelination, and compromised functional recovery in vivo. These effects in GIT1 CKO mice were reversed with the administration of soluble TNF inhibitor. Moreover, bone marrow transplantation from GIT1 CWT mice reversed adverse outcomes in GIT1 CKO mice, further indicating the role of macrophage GIT1 in modulating spinal cord injury repair. Our in vitro experiments showed that macrophage GIT1 plays a critical role in secreting TNFα and influences the differentiation of oligodendrocyte precursor cells (OPCs) after stimulation with myelin debris. Collectively, our data uncovered a new role of macrophage GIT1 in regulating the transformation of OPCs into mOLs, essential for functional remyelination after SCI, suggesting that macrophage GIT1 could be a promising treatment target of SCI.
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Affiliation(s)
- Hao Liu
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
- Jiangsu Institute of Functional Reconstruction and Rehabilitation, Nanjing, Jiangsu, China
- Spinal Cord Disease Research Center, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Jiang Yi
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
- Jiangsu Institute of Functional Reconstruction and Rehabilitation, Nanjing, Jiangsu, China
- Spinal Cord Disease Research Center, Nanjing Medical University, Nanjing, Jiangsu, China
- Department of Orthopedics, Yancheng Third People's Hospital, Yancheng, Jiangsu, China
| | - Chenxi Zhang
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
- Jiangsu Institute of Functional Reconstruction and Rehabilitation, Nanjing, Jiangsu, China
- Spinal Cord Disease Research Center, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Yin Li
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
- Jiangsu Institute of Functional Reconstruction and Rehabilitation, Nanjing, Jiangsu, China
- Spinal Cord Disease Research Center, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Qian Wang
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
- Jiangsu Institute of Functional Reconstruction and Rehabilitation, Nanjing, Jiangsu, China
- Spinal Cord Disease Research Center, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Shenyu Wang
- Department of Pathology, Molecular and Cell-Based Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Siming Dai
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
- Jiangsu Institute of Functional Reconstruction and Rehabilitation, Nanjing, Jiangsu, China
- Spinal Cord Disease Research Center, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Ziyang Zheng
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
- Jiangsu Institute of Functional Reconstruction and Rehabilitation, Nanjing, Jiangsu, China
- Spinal Cord Disease Research Center, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Tao Jiang
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
- Jiangsu Institute of Functional Reconstruction and Rehabilitation, Nanjing, Jiangsu, China
- Spinal Cord Disease Research Center, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Peng Gao
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
- Jiangsu Institute of Functional Reconstruction and Rehabilitation, Nanjing, Jiangsu, China
- Spinal Cord Disease Research Center, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Ao Xue
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
- Jiangsu Institute of Functional Reconstruction and Rehabilitation, Nanjing, Jiangsu, China
- Spinal Cord Disease Research Center, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Zhenfei Huang
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
- Jiangsu Institute of Functional Reconstruction and Rehabilitation, Nanjing, Jiangsu, China
- Spinal Cord Disease Research Center, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Fanqi Kong
- Department of Orthopedics, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
| | - Yongxiang Wang
- Department of Orthopedics, Clinical Medical College, Yangzhou University, Yangzhou, China
- Northern Jiangsu People's Hospital, Yangzhou, China
| | - Baorong He
- Department of Spine Surgery, Honghui-hospital, Xi'an Jiaotong Uinversity, School of Medicine, Xi'an, China
| | - Xiaodong Guo
- Department of Orthopedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qingqing Li
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
- Jiangsu Institute of Functional Reconstruction and Rehabilitation, Nanjing, Jiangsu, China
- Spinal Cord Disease Research Center, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Jian Chen
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
- Jiangsu Institute of Functional Reconstruction and Rehabilitation, Nanjing, Jiangsu, China
- Spinal Cord Disease Research Center, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Guoyong Yin
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
- Jiangsu Institute of Functional Reconstruction and Rehabilitation, Nanjing, Jiangsu, China
- Spinal Cord Disease Research Center, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Shujie Zhao
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
- Jiangsu Institute of Functional Reconstruction and Rehabilitation, Nanjing, Jiangsu, China
- Spinal Cord Disease Research Center, Nanjing Medical University, Nanjing, Jiangsu, China
- Nash Family Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA
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Jhelum P, Zandee S, Ryan F, Zarruk JG, Michalke B, Venkataramani V, Curran L, Klement W, Prat A, David S. Ferroptosis induces detrimental effects in chronic EAE and its implications for progressive MS. Acta Neuropathol Commun 2023; 11:121. [PMID: 37491291 PMCID: PMC10369714 DOI: 10.1186/s40478-023-01617-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 07/07/2023] [Indexed: 07/27/2023] Open
Abstract
Ferroptosis is a form of lipid peroxidation-mediated cell death and damage triggered by excess iron and insufficiency in the glutathione antioxidant pathway. Oxidative stress is thought to play a crucial role in progressive forms of multiple sclerosis (MS) in which iron deposition occurs. In this study we assessed if ferroptosis plays a role in a chronic form of experimental autoimmune encephalomyelitis (CH-EAE), a mouse model used to study MS. Changes were detected in the mRNA levels of several ferroptosis genes in CH-EAE but not in relapsing-remitting EAE. At the protein level, expression of iron importers is increased in the earlier stages of CH-EAE (onset and peak). While expression of hemoxygenase-1, which mobilizes iron from heme, likely from phagocytosed material, is increased in macrophages at the peak and progressive stages. Excess iron in cells is stored safely in ferritin, which increases with disease progression. Harmful, redox active iron is released from ferritin when shuttled to autophagosomes by 'nuclear receptor coactivator 4' (NCOA4). NCOA4 expression increases at the peak and progressive stages of CH-EAE and accompanied by increase in redox active ferrous iron. These changes occur in parallel with reduction in the antioxidant pathway (system xCT, glutathione peroxidase 4 and glutathione), and accompanied by increased lipid peroxidation. Mice treated with a ferroptosis inhibitor for 2 weeks starting at the peak of CH-EAE paralysis, show significant improvements in function and pathology. Autopsy samples of tissue sections of secondary progressive MS (SPMS) showed NCOA4 expression in macrophages and oligodendrocytes along the rim of mixed active/inactive lesions, where ferritin+ and iron containing cells are located. Cells expressing NCOA4 express less ferritin, suggesting ferritin degradation and release of redox active iron, as indicated by increased lipid peroxidation. These data suggest that ferroptosis is likely to contribute to pathogenesis in CH-EAE and SPMS.
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Affiliation(s)
- Priya Jhelum
- Centre for Research in Neuroscience and BRaIN Program, Research Institute of the McGill University Health Centre (RI-MUHC), Livingston Hall, Room L7-210, 1650 Cedar Ave., Montreal, QC, H3G 1A4, Canada
| | - Stephanie Zandee
- Neuroimmunology Research Laboratory, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, H2X 0A9, Canada
- Department of Neuroscience, Faculty of Medicine, Université de Montréal, Montreal, Canada
| | - Fari Ryan
- Centre for Research in Neuroscience and BRaIN Program, Research Institute of the McGill University Health Centre (RI-MUHC), Livingston Hall, Room L7-210, 1650 Cedar Ave., Montreal, QC, H3G 1A4, Canada
| | - Juan G Zarruk
- Centre for Research in Neuroscience and BRaIN Program, Research Institute of the McGill University Health Centre (RI-MUHC), Livingston Hall, Room L7-210, 1650 Cedar Ave., Montreal, QC, H3G 1A4, Canada
| | - Bernhard Michalke
- Research Unit Analytical BioGeoChemistry, Helmholz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - Vivek Venkataramani
- Comprehensive Cancer Center Mainfranken, University Hospital Würzburg, 97080, Würzburg, Germany
| | - Laura Curran
- Centre for Research in Neuroscience and BRaIN Program, Research Institute of the McGill University Health Centre (RI-MUHC), Livingston Hall, Room L7-210, 1650 Cedar Ave., Montreal, QC, H3G 1A4, Canada
| | - Wendy Klement
- Neuroimmunology Research Laboratory, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, H2X 0A9, Canada
- Department of Neuroscience, Faculty of Medicine, Université de Montréal, Montreal, Canada
| | - Alexandre Prat
- Neuroimmunology Research Laboratory, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, H2X 0A9, Canada
- Department of Neuroscience, Faculty of Medicine, Université de Montréal, Montreal, Canada
| | - Samuel David
- Centre for Research in Neuroscience and BRaIN Program, Research Institute of the McGill University Health Centre (RI-MUHC), Livingston Hall, Room L7-210, 1650 Cedar Ave., Montreal, QC, H3G 1A4, Canada.
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4
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Khattar N, Triebswetter C, Kiely M, Ferrucci L, Resnick SM, Spencer RG, Bouhrara M. Investigation of the association between cerebral iron content and myelin content in normative aging using quantitative magnetic resonance neuroimaging. Neuroimage 2021; 239:118267. [PMID: 34139358 PMCID: PMC8370037 DOI: 10.1016/j.neuroimage.2021.118267] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 06/10/2021] [Accepted: 06/11/2021] [Indexed: 12/24/2022] Open
Abstract
Myelin loss and iron accumulation are cardinal features of aging and various neurodegenerative diseases. Oligodendrocytes incorporate iron as a metabolic substrate for myelin synthesis and maintenance. An emerging hypothesis in Alzheimer’s disease research suggests that myelin breakdown releases substantial stores of iron that may accumulate, leading to further myelin breakdown and neurodegeneration. We assessed associations between iron content and myelin content in critical brain regions using quantitative magnetic resonance imaging (MRI) on a cohort of cognitively unimpaired adults ranging in age from 21 to 94 years. We measured whole-brain myelin water fraction (MWF), a surrogate of myelin content, using multicomponent relaxometry, and whole-brain iron content using susceptibility weighted imaging in all individuals. MWF was negatively associated with iron content in most brain regions evaluated indicating that lower myelin content corresponds to higher iron content. Moreover, iron content was significantly higher with advanced age in most structures, with men exhibiting a trend towards higher iron content as compared to women. Finally, relationship between MWF and age, in all brain regions investigated, suggests that brain myelination continues until middle age, followed by degeneration at older ages. This work establishes a foundation for further investigations of the etiology and sequelae of myelin breakdown and iron accumulation in neurodegeneration and may lead to new imaging markers for disease progression and treatment.
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Affiliation(s)
- Nikkita Khattar
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, 21224 MD, United States
| | - Curtis Triebswetter
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, 21224 MD, United States
| | - Matthew Kiely
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, 21224 MD, United States
| | - Luigi Ferrucci
- Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Baltimore, 21224 MD, United States
| | - Susan M Resnick
- Laboratory of Behavioral Neuroscience, National Institute on Aging, National Institutes of Health, Baltimore, 21224 MD, United States
| | - Richard G Spencer
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, 21224 MD, United States
| | - Mustapha Bouhrara
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, 21224 MD, United States.
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5
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Goodus MT, Carson KE, Sauerbeck AD, Dey P, Alfredo AN, Popovich PG, Bruno RS, McTigue DM. Liver inflammation at the time of spinal cord injury enhances intraspinal pathology, liver injury, metabolic syndrome and locomotor deficits. Exp Neurol 2021; 342:113725. [PMID: 33933462 DOI: 10.1016/j.expneurol.2021.113725] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 04/08/2021] [Accepted: 04/22/2021] [Indexed: 02/07/2023]
Abstract
The current high obesity rates mean that neurological injuries are increasingly sustained on a background of systemic pathology, including liver inflammation, which likely has a negative impact on outcomes. Because obesity involves complex pathology, the effect of hepatic inflammation alone on neurological recovery is unknown. Thus, here we used a gain-of-function model to test if liver inflammation worsens outcome from spinal cord injury (SCI) in rats. Results show liver inflammation concomitant with SCI exacerbated intraspinal pathology and impaired locomotor recovery. Hepatic inflammation also potentiated SCI-induced non-alcoholic steatohepatitis (NASH), endotoxemia and insulin resistance. Circulating and cerebrospinal levels of the liver-derived protein Fetuin-A were higher in SCI rats with liver inflammation, and, when microinjected into intact spinal cords, Fetuin-A caused macrophage activation and neuron loss. Thus, liver inflammation functions as a disease modifying factor to impair recovery from SCI, and Fetuin-A is a potential neuropathological mediator. Since SCI alone induces acute liver inflammation, the liver may be a novel clinical target for improving recovery from SCI.
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Affiliation(s)
- Matthew T Goodus
- The Belford Center for Spinal Cord Injury, Ohio State University, Columbus, OH, USA; Department of Neuroscience, College of Medicine, Ohio State University, Columbus, OH, USA
| | - Kaitlin E Carson
- The Belford Center for Spinal Cord Injury, Ohio State University, Columbus, OH, USA; Department of Neuroscience, College of Medicine, Ohio State University, Columbus, OH, USA
| | - Andrew D Sauerbeck
- The Belford Center for Spinal Cord Injury, Ohio State University, Columbus, OH, USA; Department of Neurology, Washington University in St. Louis, Missouri, USA
| | - Priyankar Dey
- Department of Biotechnology, Thapar Institute of Engineering and Technology, Patiala, Punjab, India
| | - Anthony N Alfredo
- The Belford Center for Spinal Cord Injury, Ohio State University, Columbus, OH, USA; Department of Neuroscience, College of Medicine, Ohio State University, Columbus, OH, USA
| | - Phillip G Popovich
- The Belford Center for Spinal Cord Injury, Ohio State University, Columbus, OH, USA; Department of Neuroscience, College of Medicine, Ohio State University, Columbus, OH, USA
| | - Richard S Bruno
- Department of Human Sciences, College of Education and Human Ecology, The Ohio State University, Columbus, OH, USA
| | - Dana M McTigue
- The Belford Center for Spinal Cord Injury, Ohio State University, Columbus, OH, USA; Department of Neuroscience, College of Medicine, Ohio State University, Columbus, OH, USA.
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6
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Min YJ, Ling EA, Li F. Immunomodulatory Mechanism and Potential Therapies for Perinatal Hypoxic-Ischemic Brain Damage. Front Pharmacol 2020; 11:580428. [PMID: 33536907 PMCID: PMC7849181 DOI: 10.3389/fphar.2020.580428] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 10/13/2020] [Indexed: 12/13/2022] Open
Abstract
Hypoxia-ischemia (HI) is one of the most common causes of death and disability in neonates. Currently, the only available licensed treatment for perinatal HI is hypothermia. However, it alone is not sufficient to prevent the brain injuries and/or neurological dysfunction related to HI. Perinatal HI can activate the immune system and trigger the peripheral and central responses which involve the immune cell activation, increase in production of immune mediators and release of reactive oxygen species. There is mounting evidence indicating that regulation of immune response can effectively rescue the outcomes of brain injury in experimental perinatal HI models such as Rice-Vannucci model of newborn hypoxic-ischemic brain damage (HIBD), local transient cerebral ischemia and reperfusion model, perinatal asphyxia model, and intrauterine hypoxia model. This review summarizes the many studies about immunomodulatory mechanisms and therapies for HI. It highlights the important actions of some widely documented therapeutic agents for effective intervening of HI related brain damage, namely, HIBD, such as EPO, FTY720, Minocycline, Gastrodin, Breviscapine, Milkvetch etc. In this connection, it has been reported that the ameboid microglial cells featured prominently in the perinatal brain represent the key immune cells involved in HIBD. To this end, drugs, chemical agents and herbal compounds which have the properties to suppress microglia activation have recently been extensively explored and identified as potential therapeutic agents or strategies for amelioration of neonatal HIBD.
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Affiliation(s)
- Ying-Jun Min
- Department of Pathology and Pathophysiology, School of Basic Medical Sciences, Kunming Medical University, Kunming, China
| | - Eng-Ang Ling
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Fan Li
- Department of Pathology and Pathophysiology, School of Basic Medical Sciences, Kunming Medical University, Kunming, China
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Grubić Kezele T, Ćurko-Cofek B. Age-Related Changes and Sex-Related Differences in Brain Iron Metabolism. Nutrients 2020; 12:E2601. [PMID: 32867052 PMCID: PMC7551829 DOI: 10.3390/nu12092601] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 08/24/2020] [Accepted: 08/25/2020] [Indexed: 12/21/2022] Open
Abstract
Iron is an essential element that participates in numerous cellular processes. Any disruption of iron homeostasis leads to either iron deficiency or iron overload, which can be detrimental for humans' health, especially in elderly. Each of these changes contributes to the faster development of many neurological disorders or stimulates progression of already present diseases. Age-related cellular and molecular alterations in iron metabolism can also lead to iron dyshomeostasis and deposition. Iron deposits can contribute to the development of inflammation, abnormal protein aggregation, and degeneration in the central nervous system (CNS), leading to the progressive decline in cognitive processes, contributing to pathophysiology of stroke and dysfunctions of body metabolism. Besides, since iron plays an important role in both neuroprotection and neurodegeneration, dietary iron homeostasis should be considered with caution. Recently, there has been increased interest in sex-related differences in iron metabolism and iron homeostasis. These differences have not yet been fully elucidated. In this review we will discuss the latest discoveries in iron metabolism, age-related changes, along with the sex differences in iron content in serum and brain, within the healthy aging population and in neurological disorders such as multiple sclerosis, Parkinson's disease, Alzheimer's disease, and stroke.
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Affiliation(s)
- Tanja Grubić Kezele
- Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, Braće Branchetta 20, 51000 Rijeka, Croatia;
- Clinical Department for Clinical Microbiology, Clinical Hospital Center Rijeka, Krešimirova 42, 51000 Rijeka, Croatia
| | - Božena Ćurko-Cofek
- Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, Braće Branchetta 20, 51000 Rijeka, Croatia;
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Lee NJ, Ha SK, Sati P, Absinta M, Nair G, Luciano NJ, Leibovitch EC, Yen CC, Rouault TA, Silva AC, Jacobson S, Reich DS. Potential role of iron in repair of inflammatory demyelinating lesions. J Clin Invest 2020; 129:4365-4376. [PMID: 31498148 DOI: 10.1172/jci126809] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 07/16/2019] [Indexed: 12/20/2022] Open
Abstract
Inflammatory destruction of iron-rich myelin is characteristic of multiple sclerosis (MS). Although iron is needed for oligodendrocytes to produce myelin during development, its deposition has also been linked to neurodegeneration and inflammation, including in MS. We report perivascular iron deposition in multiple sclerosis lesions that was mirrored in 72 lesions from 13 marmosets with experimental autoimmune encephalomyelitis. Iron accumulated mainly inside microglia/macrophages from 6 weeks after demyelination. Consistently, expression of transferrin receptor, the brain's main iron-influx protein, increased as lesions aged. Iron was uncorrelated with inflammation and postdated initial demyelination, suggesting that iron is not directly pathogenic. Iron homeostasis was at least partially restored in remyelinated, but not persistently demyelinated, lesions. Taken together, our results suggest that iron accumulation in the weeks after inflammatory demyelination may contribute to lesion repair rather than inflammatory demyelination per se.
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Affiliation(s)
- Nathanael J Lee
- Translational Neuroradiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA.,Department of Neuroscience, Georgetown University Medical Center, Georgetown University, Washington, District of Columbia, USA
| | - Seung-Kwon Ha
- Translational Neuroradiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Pascal Sati
- Translational Neuroradiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Martina Absinta
- Translational Neuroradiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Govind Nair
- Translational Neuroradiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Nicholas J Luciano
- Translational Neuroradiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Emily C Leibovitch
- Viral Immunology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Cecil C Yen
- Cerebral Microcirculation Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Tracey A Rouault
- Section on Human Iron Metabolism, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Afonso C Silva
- Cerebral Microcirculation Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Steven Jacobson
- Viral Immunology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Daniel S Reich
- Translational Neuroradiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
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9
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Pukos N, Goodus MT, Sahinkaya FR, McTigue DM. Myelin status and oligodendrocyte lineage cells over time after spinal cord injury: What do we know and what still needs to be unwrapped? Glia 2019; 67:2178-2202. [PMID: 31444938 DOI: 10.1002/glia.23702] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 07/29/2019] [Accepted: 07/30/2019] [Indexed: 01/04/2023]
Abstract
Spinal cord injury (SCI) affects over 17,000 individuals in the United States per year, resulting in sudden motor, sensory and autonomic impairments below the level of injury. These deficits may be due at least in part to the loss of oligodendrocytes and demyelination of spared axons as it leads to slowed or blocked conduction through the lesion site. It has long been accepted that progenitor cells form new oligodendrocytes after SCI, resulting in the acute formation of new myelin on demyelinated axons. However, the chronicity of demyelination and the functional significance of remyelination remain contentious. Here we review work examining demyelination and remyelination after SCI as well as the current understanding of oligodendrocyte lineage cell responses to spinal trauma, including the surprisingly long-lasting response of NG2+ oligodendrocyte progenitor cells (OPCs) to proliferate and differentiate into new myelinating oligodendrocytes for months after SCI. OPCs are highly sensitive to microenvironmental changes, and therefore respond to the ever-changing post-SCI milieu, including influx of blood, monocytes and neutrophils; activation of microglia and macrophages; changes in cytokines, chemokines and growth factors such as ciliary neurotrophic factor and fibroblast growth factor-2; glutamate excitotoxicity; and axon degeneration and sprouting. We discuss how these changes relate to spontaneous oligodendrogenesis and remyelination, the evidence for and against demyelination being an important clinical problem and if remyelination contributes to motor recovery.
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Affiliation(s)
- Nicole Pukos
- Neuroscience Graduate Program, Ohio State University, Columbus, Ohio.,Belford Center for Spinal Cord Injury, Ohio State University, Columbus, Ohio
| | - Matthew T Goodus
- Belford Center for Spinal Cord Injury, Ohio State University, Columbus, Ohio.,Department of Neuroscience, Wexner Medical Center, Ohio State University, Columbus, Ohio
| | - Fatma R Sahinkaya
- Neuroscience Graduate Program, Ohio State University, Columbus, Ohio
| | - Dana M McTigue
- Belford Center for Spinal Cord Injury, Ohio State University, Columbus, Ohio.,Department of Neuroscience, Wexner Medical Center, Ohio State University, Columbus, Ohio
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10
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Multi-copper ferroxidase deficiency leads to iron accumulation and oxidative damage in astrocytes and oligodendrocytes. Sci Rep 2019; 9:9437. [PMID: 31263155 PMCID: PMC6603037 DOI: 10.1038/s41598-019-46019-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 06/21/2019] [Indexed: 12/31/2022] Open
Abstract
Accumulation of iron has been associated with the pathobiology of various disorders of the central nervous system. Our previous work has shown that hephaestin (Heph) and ceruloplasmin (Cp) double knockout (KO) mice induced iron accumulation in multiple brain regions and that this was paralleled by increased oxidative damage and deficits in cognition and memory. In this study, we enriched astrocytes and oligodendrocytes from the cerebral cortex of neonatal wild-type (WT), Heph KO and Cp KO mice. We demonstrated that Heph is highly expressed in oligodendrocytes, while Cp is mainly expressed in astrocytes. Iron efflux was impaired in Cp KO astrocytes and Heph KO oligodendrocytes and was associated with increased oxidative stress. The expression of Heph, Cp, and other iron-related genes was examined in astrocytes and oligodendrocytes both with and without iron treatment. Interestingly, we found that the expression of the mRNA encoding ferroportin 1, a transmembrane protein that cooperates with CP and HEPH to export iron from cells, was positively correlated with Cp expression in astrocytes, and with Heph expression in oligodendrocytes. Our findings collectively demonstrate that HEPH and CP are important for the prevention of glial iron accumulation and thus may be protective against oxidative damage.
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11
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Masaldan S, Bush AI, Devos D, Rolland AS, Moreau C. Striking while the iron is hot: Iron metabolism and ferroptosis in neurodegeneration. Free Radic Biol Med 2019; 133:221-233. [PMID: 30266679 DOI: 10.1016/j.freeradbiomed.2018.09.033] [Citation(s) in RCA: 295] [Impact Index Per Article: 59.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 09/19/2018] [Accepted: 09/20/2018] [Indexed: 02/07/2023]
Abstract
Perturbations in iron homeostasis and iron accumulation feature in several neurodegenerative disorders including Alzheimer's disease (AD), Parkinson's disease (PD) and Amyotrophic lateral sclerosis (ALS). Proteins such as α-synuclein, tau and amyloid precursor protein that are pathologically associated with neurodegeneration are involved in molecular crosstalk with iron homeostatic proteins. Quantitative susceptibility mapping, an MRI based non-invasive technique, offers proximal evaluations of iron load in regions of the brain and powerfully predicts cognitive decline. Further, small molecules that target elevated iron have shown promise against PD and AD in preclinical studies and clinical trials. Despite these strong links between altered iron homeostasis and neurodegeneration the molecular biology to describe the association between enhanced iron levels and neuron death, synaptic impairment and cognitive decline is ill defined. In this review we discuss the current understanding of brain iron homeostasis and how it may be perturbed under pathological conditions. Further, we explore the ramifications of a novel cell death pathway called ferroptosis that has provided a fresh impetus to the "metal hypothesis" of neurodegeneration. While lipid peroxidation plays a central role in the execution of this cell death modality the removal of iron through chelation or genetic modifications appears to extinguish the ferroptotic pathway. Conversely, tissues that harbour elevated iron may be predisposed to ferroptotic damage. These emerging findings are of relevance to neurodegeneration where ferroptotic signalling may offer new targets to mitigate cell death and dysfunction.
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Affiliation(s)
- Shashank Masaldan
- Melbourne Dementia Research Centre, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria 3052, Australia
| | - Ashley I Bush
- Melbourne Dementia Research Centre, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria 3052, Australia.
| | - David Devos
- Department of Neurology, ALS Center, Lille University, INSERM UMRS_1171, University Hospital Center, LICEND COEN Center, Lille, France; Department of Medical Pharmacology, Lille University, INSERM UMRS_1171, University Hospital Center, LICEND COEN Center, Lille, France
| | - Anne Sophie Rolland
- Department of Medical Pharmacology, Lille University, INSERM UMRS_1171, University Hospital Center, LICEND COEN Center, Lille, France
| | - Caroline Moreau
- Department of Neurology, ALS Center, Lille University, INSERM UMRS_1171, University Hospital Center, LICEND COEN Center, Lille, France; Department of Medical Pharmacology, Lille University, INSERM UMRS_1171, University Hospital Center, LICEND COEN Center, Lille, France
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12
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Yu FF, Chiang FL, Stephens N, Huang SY, Bilgic B, Tantiwongkosi B, Romero R. Characterization of normal-appearing white matter in multiple sclerosis using quantitative susceptibility mapping in conjunction with diffusion tensor imaging. Neuroradiology 2018; 61:71-79. [PMID: 30539215 DOI: 10.1007/s00234-018-2137-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 11/13/2018] [Indexed: 01/18/2023]
Abstract
PURPOSE Quantitative susceptibility mapping (QSM) is influenced by iron as well as myelin, which makes interpretation of pathologic changes challenging. Concurrent acquisition of MR sequences that are sensitive to axonal/myelin integrity, such as diffusion tensor imaging (DTI), may provide context for interpreting quantitative susceptibility (QS) signal. The purpose of our study was to investigate alterations in normal-appearing white matter (NAWM) in multiple sclerosis (MS) using QSM in conjunction with DTI. METHODS Twenty relapsing-remitting MS patients and 20 age-matched healthy controls (HC) were recruited for this prospective study. QS, radial diffusivity (RD), fractional anisotropy (FA), and R2* maps within the whole brain as well as individual tracts were generated for comparison between NAWM and HC white matter (HCWM). RESULTS MS lesions demonstrated significant differences in QS, FA, RD, and R2* compared to HCWM (p < 0.03). These metrics did not show a significant difference between whole-brain NAWM and HCWM. Among NAWM tracts, the cingulate gyri demonstrated significantly decreased QS compared to HCWM (p = 0.004). The forceps major showed significant differences in FA and RD without corresponding changes in QS (p < 0.01). CONCLUSION We found discordant changes in QSM and DTI metrics within the cingulate gyri and forceps major. This may potentially reflect the influence of paramagnetic substrates such as iron, which could be decreased along these NAWM tracts. Our results point to the potential role of QSM as a unique biomarker, although additional validation studies are needed.
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Affiliation(s)
- Fang F Yu
- Division of Neuroradiology, Department of Radiology, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390, USA.
- Division of Neuroradiology, Department of Radiology, Massachusetts General Hospital, Boston, MA, USA.
| | - Florence L Chiang
- Department of Radiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Nicholas Stephens
- Department of Radiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Susie Y Huang
- Division of Neuroradiology, Department of Radiology, Massachusetts General Hospital, Boston, MA, USA
- Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA, USA
| | - Berkin Bilgic
- Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA, USA
| | - Bundhit Tantiwongkosi
- Department of Radiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Rebecca Romero
- Department of Neurology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
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13
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Tran AP, Warren PM, Silver J. The Biology of Regeneration Failure and Success After Spinal Cord Injury. Physiol Rev 2018. [PMID: 29513146 DOI: 10.1152/physrev.00017.2017] [Citation(s) in RCA: 490] [Impact Index Per Article: 81.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Since no approved therapies to restore mobility and sensation following spinal cord injury (SCI) currently exist, a better understanding of the cellular and molecular mechanisms following SCI that compromise regeneration or neuroplasticity is needed to develop new strategies to promote axonal regrowth and restore function. Physical trauma to the spinal cord results in vascular disruption that, in turn, causes blood-spinal cord barrier rupture leading to hemorrhage and ischemia, followed by rampant local cell death. As subsequent edema and inflammation occur, neuronal and glial necrosis and apoptosis spread well beyond the initial site of impact, ultimately resolving into a cavity surrounded by glial/fibrotic scarring. The glial scar, which stabilizes the spread of secondary injury, also acts as a chronic, physical, and chemo-entrapping barrier that prevents axonal regeneration. Understanding the formative events in glial scarring helps guide strategies towards the development of potential therapies to enhance axon regeneration and functional recovery at both acute and chronic stages following SCI. This review will also discuss the perineuronal net and how chondroitin sulfate proteoglycans (CSPGs) deposited in both the glial scar and net impede axonal outgrowth at the level of the growth cone. We will end the review with a summary of current CSPG-targeting strategies that help to foster axonal regeneration, neuroplasticity/sprouting, and functional recovery following SCI.
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Affiliation(s)
- Amanda Phuong Tran
- Department of Neurosciences, Case Western Reserve University , Cleveland, Ohio ; and School of Biomedical Sciences, University of Leeds , Leeds , United Kingdom
| | - Philippa Mary Warren
- Department of Neurosciences, Case Western Reserve University , Cleveland, Ohio ; and School of Biomedical Sciences, University of Leeds , Leeds , United Kingdom
| | - Jerry Silver
- Department of Neurosciences, Case Western Reserve University , Cleveland, Ohio ; and School of Biomedical Sciences, University of Leeds , Leeds , United Kingdom
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14
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Cardona SM, Kim SV, Church KA, Torres VO, Cleary IA, Mendiola AS, Saville SP, Watowich SS, Parker-Thornburg J, Soto-Ospina A, Araque P, Ransohoff RM, Cardona AE. Role of the Fractalkine Receptor in CNS Autoimmune Inflammation: New Approach Utilizing a Mouse Model Expressing the Human CX3CR1 I249/M280 Variant. Front Cell Neurosci 2018; 12:365. [PMID: 30386211 PMCID: PMC6199958 DOI: 10.3389/fncel.2018.00365] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 09/26/2018] [Indexed: 12/21/2022] Open
Abstract
Multiple sclerosis (MS), an inflammatory demyelinating disease of the central nervous system (CNS) is the leading cause of non-traumatic neurological disability in young adults. Immune mediated destruction of myelin and oligodendrocytes is considered the primary pathology of MS, but progressive axonal loss is the major cause of neurological disability. In an effort to understand microglia function during CNS inflammation, our laboratory focuses on the fractalkine/CX3CR1 signaling as a regulator of microglia neurotoxicity in various models of neurodegeneration. Fractalkine (FKN) is a transmembrane chemokine expressed in the CNS by neurons and signals through its unique receptor CX3CR1 present in microglia. During experimental autoimmune encephalomyelitis (EAE), CX3CR1 deficiency confers exacerbated disease defined by severe inflammation and neuronal loss. The CX3CR1 human polymorphism I249/M280 present in ∼20% of the population exhibits reduced adhesion for FKN conferring defective signaling whose role in microglia function and influence on neurons during MS remains unsolved. The aim of this study is to assess the effect of weaker signaling through hCX3CR1I249/M280 during EAE. We hypothesize that dysregulated microglial responses due to impaired CX3CR1 signaling enhance neuronal/axonal damage. We generated an animal model replacing the mouse CX3CR1 locus for the hCX3CR1I249/M280 variant. Upon EAE induction, these mice exhibited exacerbated EAE correlating with severe inflammation and neuronal loss. We also observed that mice with aberrant CX3CR1 signaling are unable to produce FKN and ciliary neurotrophic factor during EAE in contrast to wild type mice. Our results provide validation of defective function of the hCX3CR1I249/M280 variant and the foundation to broaden the understanding of microglia dysfunction during neuroinflammation.
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Affiliation(s)
- Sandra M Cardona
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, United States.,South Texas Center for Emerging Infectious Diseases, The University of Texas at San Antonio, San Antonio, TX, United States
| | - Sangwon V Kim
- Department of Microbiology and Immunology, Sidney Kimmel Medical College of Thomas Jefferson University, Philadelphia, PA, United States
| | - Kaira A Church
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, United States
| | - Vanessa O Torres
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Ian A Cleary
- Department of Biomedical Sciences, Grand Valley State University, Allendale, MI, United States
| | - Andrew S Mendiola
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, United States.,Gladstone Institute of Neurological Disease, San Francisco, CA, United States
| | - Stephen P Saville
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, United States.,South Texas Center for Emerging Infectious Diseases, The University of Texas at San Antonio, San Antonio, TX, United States
| | - Stephanie S Watowich
- Department of Immunology, Center for Inflammation and Cancer, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Jan Parker-Thornburg
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Alejandro Soto-Ospina
- Basic Sciences Department, Research and Innovation in Chemical Formulations, University EIA, Envigado, Colombia
| | - Pedronel Araque
- Basic Sciences Department, Research and Innovation in Chemical Formulations, University EIA, Envigado, Colombia
| | | | - Astrid E Cardona
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, United States.,South Texas Center for Emerging Infectious Diseases, The University of Texas at San Antonio, San Antonio, TX, United States
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15
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Goodus MT, Sauerbeck AD, Popovich PG, Bruno RS, McTigue DM. Dietary Green Tea Extract Prior to Spinal Cord Injury Prevents Hepatic Iron Overload but Does Not Improve Chronic Hepatic and Spinal Cord Pathology in Rats. J Neurotrauma 2018; 35:2872-2882. [PMID: 30084733 DOI: 10.1089/neu.2018.5771] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Spinal cord injury (SCI) disrupts autonomic regulation of visceral organs. As a result, a leading cause of mortality in the SCI population is metabolic dysfunction, and an organ central to metabolic control is the liver. Our recent work showed that rodent SCI promotes Kupffer cell (hepatic macrophage) activation, pro-inflammatory cytokine expression, and liver steatosis. These are symptoms of nonalcoholic steatohepatitis (NASH), the hepatic manifestation of metabolic syndrome, and these pre-clinical data replicate aspects of post-SCI human metabolic dysfunction. Because metabolic profile is highly dependent on lifestyle, including diet, it is likely that lifestyle choices prior to injury influence metabolic and hepatic outcomes after SCI. Therefore, in this study we tested if a diet rich in green tea extract (GTE), a known hepatoprotective agent, that began 3 weeks before SCI and was maintained after injury, reduced indices of liver pathology or metabolic dysfunction. GTE treatment significantly reduced post-SCI hepatic iron accumulation and blunted circulating glucose elevation compared with control-diet rats. However, GTE pre-treatment did not prevent Kupffer cell activation, hepatic lipid accumulation, increased serum alanine transaminase, or circulating non-esterified fatty acids, which were all significantly increased 6 weeks post-injury. Spinal cord pathology also was unchanged by GTE. Thus, dietary GTE prior to and after SCI had only a minor hepatoprotective effect. In general, for optimal health of SCI individuals, it will be important for future studies to evaluate how other lifestyle choices made before or after SCI positively or negatively impact systemic and intraspinal outcomes and the overall metabolic health of SCI individuals.
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Affiliation(s)
- Matthew T Goodus
- 1 The Center for Brain and Spinal Cord Repair, College of Education and Human Ecology, The Ohio State University, Columbus, Ohio.,2 Department of Neuroscience, College of Education and Human Ecology, The Ohio State University, Columbus, Ohio.,3 Belford Center for Spinal Cord Injury, Wexner Medical Center, College of Education and Human Ecology, The Ohio State University, Columbus, Ohio
| | - Andrew D Sauerbeck
- 1 The Center for Brain and Spinal Cord Repair, College of Education and Human Ecology, The Ohio State University, Columbus, Ohio.,2 Department of Neuroscience, College of Education and Human Ecology, The Ohio State University, Columbus, Ohio
| | - Phillip G Popovich
- 1 The Center for Brain and Spinal Cord Repair, College of Education and Human Ecology, The Ohio State University, Columbus, Ohio.,2 Department of Neuroscience, College of Education and Human Ecology, The Ohio State University, Columbus, Ohio.,3 Belford Center for Spinal Cord Injury, Wexner Medical Center, College of Education and Human Ecology, The Ohio State University, Columbus, Ohio
| | - Richard S Bruno
- 4 Human Nutrition Program, College of Education and Human Ecology, The Ohio State University, Columbus, Ohio
| | - Dana M McTigue
- 1 The Center for Brain and Spinal Cord Repair, College of Education and Human Ecology, The Ohio State University, Columbus, Ohio.,2 Department of Neuroscience, College of Education and Human Ecology, The Ohio State University, Columbus, Ohio.,3 Belford Center for Spinal Cord Injury, Wexner Medical Center, College of Education and Human Ecology, The Ohio State University, Columbus, Ohio
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16
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The Divalent Metal Transporter 1 (DMT1) Is Required for Iron Uptake and Normal Development of Oligodendrocyte Progenitor Cells. J Neurosci 2018; 38:9142-9159. [PMID: 30190412 DOI: 10.1523/jneurosci.1447-18.2018] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 08/08/2018] [Accepted: 08/27/2018] [Indexed: 01/24/2023] Open
Abstract
The divalent metal transporter 1 (DMT1) is a multimetal transporter with a primary role in iron transport. Although DMT1 has been described previously in the CNS, nothing was known about the role of this metal transporter in oligodendrocyte maturation and myelination. To determine whether DMT1 is required for oligodendrocyte progenitor cell (OPC) maturation, we used siRNAs and the Cre-lox system to knock down/knock out DMT1 expression in vitro as well as in vivo Blocking DMT1 synthesis in primary cultures of OPCs reduced oligodendrocyte iron uptake and significantly delayed OPC development. In vivo, a significant hypomyelination was found in DMT1 conditional knock-out mice in which DMT1 was postnatally deleted in NG2- or Sox10-positive OPCs. The brain of DMT1 knock-out animals presented a decrease in the expression levels of myelin proteins and a substantial reduction in the percentage of myelinated axons. This reduced postnatal myelination was accompanied by a decrease in the number of myelinating oligodendrocytes and a rise in proliferating OPCs. Furthermore, using the cuprizone model of demyelination, we established that DMT1 deletion in NG2-positive OPCs lead to less efficient remyelination of the adult brain. These results indicate that DMT1 is vital for OPC maturation and for the normal myelination of the mouse brain.SIGNIFICANCE STATEMENT To determine whether divalent metal transporter 1 (DMT1), a multimetal transporter with a primary role in iron transport, is essential for oligodendrocyte development, we created two conditional knock-out mice in which DMT1 was postnatally deleted in NG2- or Sox10-positive oligodendrocyte progenitor cells (OPCs). We have established that DMT1 is necessary for normal OPC maturation and is required for an efficient remyelination of the adult brain. Since iron accumulation by OPCs is indispensable for myelination, understanding the iron incorporation mechanism as well as the molecules involved is critical to design new therapeutic approaches to intervene in diseases in which the myelin sheath is damaged or lost.
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17
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van Duijn S, Bulk M, van Duinen SG, Nabuurs RJA, van Buchem MA, van der Weerd L, Natté R. Cortical Iron Reflects Severity of Alzheimer's Disease. J Alzheimers Dis 2018; 60:1533-1545. [PMID: 29081415 PMCID: PMC5676973 DOI: 10.3233/jad-161143] [Citation(s) in RCA: 104] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Abnormal iron distribution in the isocortex is increasingly recognized as an in vivo marker for Alzheimer’s disease (AD). However, the contribution of iron accumulation to the AD pathology is still poorly understood. In this study, we investigated: 1) frontal cortical iron distribution in AD and normal aging and 2) the relation between iron distribution and degree of AD pathology. We used formalin fixed paraffin embedded frontal cortex from 10 AD patients, 10 elder, 10 middle aged, and 10 young controls and visualized iron with a modified Perl’s histochemical procedure. AD and elderly subjects were not different with respect to age and sex distribution. Iron distribution in the frontal cortex was not affected by normal aging but was clearly different between AD and controls. AD showed accumulation of iron in plaques, activated microglia, and, in the most severe cases, in the mid-cortical layers along myelinated fibers. The degree of altered iron accumulations was correlated to the amount of amyloid-β plaques and tau pathology in the same block, as well as to Braak stage (p < 0.001). AD and normal aging show different iron and myelin distribution in frontal cortex. These changes appear to occur after the development of the AD pathological hallmarks. These findings may help the interpretation of high resolution in vivo MRI and suggest the potential of using changes in iron-based MRI contrast to indirectly determine the degree of AD pathology in the frontal cortex.
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Affiliation(s)
- Sara van Duijn
- Department of Pathology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Marjolein Bulk
- Department of Radiology, Leiden University Medical Centre, Leiden, The Netherlands.,Department of Human Genetics, Leiden University Medical Centre, Leiden, The Netherlands.,Percuros BV, Leiden, The Netherlands
| | - Sjoerd G van Duinen
- Department of Pathology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Rob J A Nabuurs
- Department of Radiology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Mark A van Buchem
- Department of Radiology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Louise van der Weerd
- Department of Radiology, Leiden University Medical Centre, Leiden, The Netherlands.,Department of Human Genetics, Leiden University Medical Centre, Leiden, The Netherlands
| | - Remco Natté
- Department of Pathology, Leiden University Medical Centre, Leiden, The Netherlands
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18
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To Be or Not to Be: Environmental Factors that Drive Myelin Formation during Development and after CNS Trauma. ACTA ACUST UNITED AC 2018. [DOI: 10.3390/neuroglia1010007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Oligodendrocytes are specialized glial cells that myelinate central nervous system (CNS) axons. Historically, it was believed that the primary role of myelin was to compactly ensheath axons, providing the insulation necessary for rapid signal conduction. However, mounting evidence demonstrates the dynamic importance of myelin and oligodendrocytes, including providing metabolic support to neurons and regulating axon protein distribution. As such, the development and maintenance of oligodendrocytes and myelin are integral to preserving CNS homeostasis and supporting proper functioning of widespread neural networks. Environmental signals are critical for proper oligodendrocyte lineage cell progression and their capacity to form functional compact myelin; these signals are markedly disturbed by injury to the CNS, which may compromise endogenous myelin repair capabilities. This review outlines some key environmental factors that drive myelin formation during development and compares that to the primary factors that define a CNS injury milieu. We aim to identify developmental factors disrupted after CNS trauma as well as pathogenic factors that negatively impact oligodendrocyte lineage cells, as these are potential therapeutic targets to promote myelin repair after injury or disease.
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19
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Adiele RC, Adiele CA. Metabolic defects in multiple sclerosis. Mitochondrion 2017; 44:7-14. [PMID: 29246870 DOI: 10.1016/j.mito.2017.12.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 10/12/2017] [Accepted: 12/11/2017] [Indexed: 02/07/2023]
Abstract
Brain injuries in multiple sclerosis (MS) involve immunopathological, structural and metabolic defects on myelin sheath, oligodendrocytes (OLs), axons and neurons suggesting that different cellular mechanisms ultimately result in the formation of MS plaques, demyelination, inflammation and brain damage. Bioenergetics, oxygen and ion metabolism dominate the metabolic and biochemical pathways that maintain neuronal viability and impulse transmission which directly or indirectly point to mitochondrial integrity and adenosine triphosphate (ATP) availability indicating the involvement of mitochondria in the pathogenesis of MS. Loss of myelin proteins including myelin basic protein (MBP), proteolipid protein (PLP), myelin associated glycoprotein (MAG), myelin oligodendrocyte glycoproetin (MOG), 2, 3,-cyclic nucleotide phosphodiestarase (CNPase); microglia and microphage activation, oligodendrocyte apoptosis as well as expression of inducible nitric oxide synthase (i-NOS) and myeloperoxidase activities have been implicated in a subset of Balo's type and relapsing remitting MS (RRMS) lesions indicating the involvement of metabolic defects and oxidative stress in MS. Here, we provide an insighting review of defects in cellular metabolism including energy, oxygen and metal metabolism in MS as well as the relevance of animal models of MS in understanding the molecular, biochemical and cellular mechanisms of MS pathogenesis. Additionally, we also discussed the potential for mitochondrial targets and antioxidant protection for therapeutic benefits in MS.
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Affiliation(s)
- Reginald C Adiele
- Department of Anatomy and Cell Biology, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada; Cameco MS Neuroscience Research Center, Saskatoon City Hospital, Saskatoon, SK, Canada; Department of Public Health, Concordia University of Edmonton, Edmonton, AB, Canada.
| | - Chiedukam A Adiele
- Department of Clinical Pharmacy, Faculty of Pharmaceutical Sciences, University of Nigeria, Nsukka, Nigeria
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20
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Intraspinal TLR4 activation promotes iron storage but does not protect neurons or oligodendrocytes from progressive iron-mediated damage. Exp Neurol 2017; 298:42-56. [PMID: 28851597 DOI: 10.1016/j.expneurol.2017.08.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 08/21/2017] [Accepted: 08/25/2017] [Indexed: 11/21/2022]
Abstract
Iron is essential for basic cellular functions but in excess is highly toxic. For this reason, free iron and iron storage are controlled in the periphery by elaborate regulatory mechanisms. In contrast, iron regulation in the central nervous system (CNS) is not well defined. Given that excess iron is present after trauma, hemorrhagic stroke and neurodegeneration, understanding normal iron regulation and promoting iron uptake in CNS pathology is crucial. Peripherally, toll-like receptor 4 (TLR4) activation promotes iron sequestration by macrophages. Notably, iron-rich sites of CNS pathology typically contain TLR4 agonists, which may promote iron uptake. Indeed, our recent work showed impaired iron storage after acute spinal cord injury in mice with TLR4 deficiency. Here we used a reductionist model to ask if TLR4 activation in the CNS stimulates iron uptake and promotes neuroprotection from iron-induced toxicity. For this, we measured the ability of microglia/macrophages to sequester exogenous iron and prevent pathology with and without concomitant intraspinal TLR4 activation. Results show that, similar to the periphery, activating intraspinal TLR4 via focal LPS injection increased mRNA encoding iron uptake and storage proteins and promoted iron sequestration into ferritin-expressing macrophages. However, this did not prevent oligodendrocyte and neuron loss. Moreover, replacement of oligodendrocytes by progenitor cells - a normally robust response to in vivo macrophage TLR4 activation - was significantly reduced if iron was present concomitant with TLR4 activation. Thus, while TLR4 signaling promotes CNS iron uptake, future work needs to determine ways to enhance iron removal without blocking the reparative effects of innate immune receptor signaling.
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21
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TLR4 Deficiency Impairs Oligodendrocyte Formation in the Injured Spinal Cord. J Neurosci 2017; 36:6352-64. [PMID: 27277810 DOI: 10.1523/jneurosci.0353-16.2016] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 05/05/2016] [Indexed: 12/12/2022] Open
Abstract
UNLABELLED Acute oligodendrocyte (OL) death after traumatic spinal cord injury (SCI) is followed by robust neuron-glial antigen 2 (NG2)-positive OL progenitor proliferation and differentiation into new OLs. Inflammatory mediators are prevalent during both phases and can influence the fate of NG2 cells and OLs. Specifically, toll-like receptor (TLR) 4 signaling induces OL genesis in the naive spinal cord, and lack of TLR4 signaling impairs white matter sparing and functional recovery after SCI. Therefore, we hypothesized that TLR4 signaling may regulate oligodendrogenesis after SCI. C3H/HeJ (TLR4-deficient) and control (C3H/HeOuJ) mice received a moderate midthoracic spinal contusion. TLR4-deficient mice showed worse functional recovery and reduced OL numbers compared with controls at 24 h after injury through chronic time points. Acute OL loss was accompanied by reduced ferritin expression, which is regulated by TLR4 and needed for effective iron storage. TLR4-deficient injured spinal cords also displayed features consistent with reduced OL genesis, including reduced NG2 expression, fewer BrdU-positive OLs, altered BMP4 signaling and inhibitor of differentiation 4 (ID4) expression, and delayed myelin phagocytosis. Expression of several factors, including IGF-1, FGF2, IL-1β, and PDGF-A, was altered in TLR4-deficient injured spinal cords compared with wild types. Together, these data show that TLR4 signaling after SCI is important for OL lineage cell sparing and replacement, as well as in regulating cytokine and growth factor expression. These results highlight new roles for TLR4 in endogenous SCI repair and emphasize that altering the function of a single immune-related receptor can dramatically change the reparative responses of multiple cellular constituents in the injured CNS milieu. SIGNIFICANCE STATEMENT Myelinating cells of the CNS [oligodendrocytes (OLs)] are killed for several weeks after traumatic spinal cord injury (SCI), but they are replaced by resident progenitor cells. How the concurrent inflammatory signaling affects this endogenous reparative response is unclear. Here, we provide evidence that immune receptor toll-like receptor 4 (TLR4) supports OL lineage cell sparing, long-term OL and OL progenitor replacement, and chronic functional recovery. We show that TLR4 signaling is essential for acute iron storage, regulating cytokine and growth factor expression, and efficient myelin debris clearance, all of which influence OL replacement. Importantly, the current study reveals that a single immune receptor is essential for repair responses after SCI, and the potential mechanisms of this beneficial effect likely change over time after injury.
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22
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Popescu BF, Frischer JM, Webb SM, Tham M, Adiele RC, Robinson CA, Fitz-Gibbon PD, Weigand SD, Metz I, Nehzati S, George GN, Pickering IJ, Brück W, Hametner S, Lassmann H, Parisi JE, Yong G, Lucchinetti CF. Pathogenic implications of distinct patterns of iron and zinc in chronic MS lesions. Acta Neuropathol 2017; 134:45-64. [PMID: 28332093 PMCID: PMC5486634 DOI: 10.1007/s00401-017-1696-8] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 03/13/2017] [Accepted: 03/14/2017] [Indexed: 12/19/2022]
Abstract
Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system (CNS) in which oligodendrocytes, the CNS cells that stain most robustly for iron and myelin are the targets of injury. Metals are essential for normal CNS functioning, and metal imbalances have been linked to demyelination and neurodegeneration. Using a multidisciplinary approach involving synchrotron techniques, iron histochemistry and immunohistochemistry, we compared the distribution and quantification of iron and zinc in MS lesions to the surrounding normal appearing and periplaque white matter, and assessed the involvement of these metals in MS lesion pathogenesis. We found that the distribution of iron and zinc is heterogeneous in MS plaques, and with few remarkable exceptions they do not accumulate in chronic MS lesions. We show that brain iron tends to decrease with increasing age and disease duration of MS patients; reactive astrocytes organized in large astrogliotic areas in a subset of smoldering and inactive plaques accumulate iron and safely store it in ferritin; a subset of smoldering lesions do not contain a rim of iron-loaded macrophages/microglia; and the iron content of shadow plaques varies with the stage of remyelination. Zinc in MS lesions was generally decreased, paralleling myelin loss. Iron accumulates concentrically in a subset of chronic inactive lesions suggesting that not all iron rims around MS lesions equate with smoldering plaques. Upon degeneration of iron-loaded microglia/macrophages, astrocytes may form an additional protective barrier that may prevent iron-induced oxidative damage.
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Affiliation(s)
- Bogdan F Popescu
- Department of Anatomy and Cell Biology, College of Medicine, University of Saskatchewan, 701 Queen Street, Saskatoon, SK, S7N 5E5, Canada.
- Cameco MS Neuroscience Research Center, University of Saskatchewan, 701 Queen Street, Saskatoon City Hospital, Rm 5800, Saskatoon, SK, S7K 0M7, Canada.
| | - Josa M Frischer
- Department of Neurosurgery, Medical University Vienna, Vienna, Austria
| | - Samuel M Webb
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Mylyne Tham
- Department of Anatomy and Cell Biology, College of Medicine, University of Saskatchewan, 701 Queen Street, Saskatoon, SK, S7N 5E5, Canada
- Cameco MS Neuroscience Research Center, University of Saskatchewan, 701 Queen Street, Saskatoon City Hospital, Rm 5800, Saskatoon, SK, S7K 0M7, Canada
| | - Reginald C Adiele
- Department of Anatomy and Cell Biology, College of Medicine, University of Saskatchewan, 701 Queen Street, Saskatoon, SK, S7N 5E5, Canada
- Cameco MS Neuroscience Research Center, University of Saskatchewan, 701 Queen Street, Saskatoon City Hospital, Rm 5800, Saskatoon, SK, S7K 0M7, Canada
| | - Christopher A Robinson
- Department of Pathology and Laboratory Medicine, Saskatoon Health Region/College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada
| | - Patrick D Fitz-Gibbon
- Department of Health Sciences Research, Mayo Clinic, College of Medicine, Rochester, MN, USA
| | - Stephen D Weigand
- Department of Health Sciences Research, Mayo Clinic, College of Medicine, Rochester, MN, USA
| | - Imke Metz
- Department of Neuropathology, University of Göttingen, Göttingen, Germany
| | - Susan Nehzati
- Molecular and Environmental Science Research Group, Department of Geological Sciences, University of Saskatchewan, Saskatoon, Canada
| | - Graham N George
- Molecular and Environmental Science Research Group, Department of Geological Sciences, University of Saskatchewan, Saskatoon, Canada
- Toxicology Center, University of Saskatchewan, Saskatoon, Canada
- Department of Chemistry, University of Saskatchewan, Saskatoon, Canada
| | - Ingrid J Pickering
- Molecular and Environmental Science Research Group, Department of Geological Sciences, University of Saskatchewan, Saskatoon, Canada
- Toxicology Center, University of Saskatchewan, Saskatoon, Canada
- Department of Chemistry, University of Saskatchewan, Saskatoon, Canada
| | - Wolfgang Brück
- Department of Neuropathology, University of Göttingen, Göttingen, Germany
| | - Simon Hametner
- Department of Neuroimmunology, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Hans Lassmann
- Department of Neuroimmunology, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Joseph E Parisi
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Guo Yong
- Department of Neurology, Mayo Clinic, College of Medicine, 200 First Street SW, Rochester, MN, 55905, USA
| | - Claudia F Lucchinetti
- Department of Neurology, Mayo Clinic, College of Medicine, 200 First Street SW, Rochester, MN, 55905, USA.
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23
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Church JS, Milich LM, Lerch JK, Popovich PG, McTigue DM. E6020, a synthetic TLR4 agonist, accelerates myelin debris clearance, Schwann cell infiltration, and remyelination in the rat spinal cord. Glia 2017; 65:883-899. [PMID: 28251686 DOI: 10.1002/glia.23132] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 02/02/2017] [Accepted: 02/03/2017] [Indexed: 12/26/2022]
Abstract
Oligodendrocyte progenitor cells (OPCs) are present throughout the adult brain and spinal cord and can replace oligodendrocytes lost to injury, aging, or disease. Their differentiation, however, is inhibited by myelin debris, making clearance of this debris an important step for cellular repair following demyelination. In models of peripheral nerve injury, TLR4 activation by lipopolysaccharide (LPS) promotes macrophage phagocytosis of debris. Here we tested whether the novel synthetic TLR4 agonist E6020, a Lipid A mimetic, promotes myelin debris clearance and remyelination in spinal cord white matter following lysolecithin-induced demyelination. In vitro, E6020 induced TLR4-dependent cytokine expression (TNFα, IL1β, IL-6) and NF-κB signaling, albeit at ∼10-fold reduced potency compared to LPS. Microinjection of E6020 into the intact rat spinal cord gray/white matter border induced macrophage activation, OPC proliferation, and robust oligodendrogenesis, similar to what we described previously using an intraspinal LPS microinjection model. Finally, a single co-injection of E6020 with lysolecithin into spinal cord white matter increased axon sparing, accelerated myelin debris clearance, enhanced Schwann cell infiltration into demyelinated lesions, and increased the number of remyelinated axons. In vitro assays confirmed that direct stimulation of macrophages by E6020 stimulates myelin phagocytosis. These data implicate TLR4 signaling in promoting repair after CNS demyelination, likely by stimulating phagocytic activity of macrophages, sparing axons, recruiting myelinating cells, and promoting remyelination. This work furthers our understanding of immune-myelin interactions and identifies a novel synthetic TLR4 agonist as a potential therapeutic avenue for white matter demyelinating conditions such as spinal cord injury and multiple sclerosis.
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Affiliation(s)
- Jamie S Church
- Neuroscience Graduate Program, The Ohio State University, Columbus, Ohio, USA.,Center for Brain and Spinal Cord Repair, The Ohio State University, Columbus, Ohio, USA
| | - Lindsay M Milich
- Department of Neuroscience, The Ohio State University, Columbus, Ohio, USA
| | - Jessica K Lerch
- Center for Brain and Spinal Cord Repair, The Ohio State University, Columbus, Ohio, USA.,Department of Neuroscience, The Ohio State University, Columbus, Ohio, USA
| | - Phillip G Popovich
- Center for Brain and Spinal Cord Repair, The Ohio State University, Columbus, Ohio, USA.,Department of Neuroscience, The Ohio State University, Columbus, Ohio, USA
| | - Dana M McTigue
- Center for Brain and Spinal Cord Repair, The Ohio State University, Columbus, Ohio, USA.,Department of Neuroscience, The Ohio State University, Columbus, Ohio, USA
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24
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Absinta M, Sati P, Schindler M, Leibovitch EC, Ohayon J, Wu T, Meani A, Filippi M, Jacobson S, Cortese ICM, Reich DS. Persistent 7-tesla phase rim predicts poor outcome in new multiple sclerosis patient lesions. J Clin Invest 2016; 126:2597-609. [PMID: 27270171 DOI: 10.1172/jci86198] [Citation(s) in RCA: 190] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 04/12/2016] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND In some active multiple sclerosis (MS) lesions, a strong immune reaction at the lesion edge may contain growth and thereby isolate the lesion from the surrounding parenchyma. Our previous studies suggest that this process involves opening of the blood-brain barrier in capillaries at the lesion edge, seen on MRI as centripetal contrast enhancement and a colocalized phase rim. We hypothesized that using these features to characterize early lesion evolution will allow in vivo tracking of tissue degeneration and/or repair, thus improving the evaluation of potential therapies for chronic active lesions. METHODS Centripetally and centrifugally enhancing lesions were studied in 17 patients with MS using 7-tesla MRI. High-resolution, susceptibility-weighted, T1-weighted (before/after gadolinium), and dynamic contrast-enhanced scans were acquired at baseline and months 1, 3, 6, and 12. For each lesion, time evolution of the phase rim, lesion volume, and T1 hypointensity were assessed. In autopsies of 3 progressive MS cases, the histopathology of the phase rim was determined. RESULTS In centripetal lesions, a phase rim colocalized with initial contrast enhancement. In 12 of 22, this phase rim persisted after enhancement resolved. Compared with centripetal lesions with transient rim, those with persistent rim had less volume shrinkage and became more T1 hypointense between months 3 and 12. No centrifugal lesions developed phase rims at any time point. Pathologically, persistent rims corresponded to an iron-laden inflammatory myeloid cell population at the edge of chronic demyelinated lesions. CONCLUSION In early lesion evolution, a persistent phase rim in lesions that shrink least and become more T1 hypointense over time suggests that the rim might mark failure of early lesion repair and/or irreversible tissue damage. In later stages of MS, phase rim lesions continue to smolder, exerting detrimental effects on affected brain tissue. TRIAL REGISTRATION NCT00001248. FUNDING The Intramural Research Program of NINDS supported this study.
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25
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Rawji KS, Mishra MK, Yong VW. Regenerative Capacity of Macrophages for Remyelination. Front Cell Dev Biol 2016; 4:47. [PMID: 27243011 PMCID: PMC4873494 DOI: 10.3389/fcell.2016.00047] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Accepted: 05/06/2016] [Indexed: 11/13/2022] Open
Abstract
White matter injury, consisting of loss of axons, myelin, and oligodendrocytes, is common in many neurological disorders and is believed to underlie several motor and sensory deficits. Remyelination is the process in which the insulative myelin sheath is restored to axons, thereby facilitating recovery from functional loss. Remyelination proceeds with oligodendrocyte precursor cells (OPCs) that differentiate into oligodendrocytes to synthesize the new myelin sheath after demyelination. This process is influenced by several factors, including trophic factors, inhibitory molecules in the lesion microenvironment, age of the subject, as well as the inflammatory response. Currently studied strategies that enhance remyelination consist of pharmacological approaches that directly induce OPC differentiation or using agents to neutralize the inhibitory microenvironment. Another strategy is to harness a reparative inflammatory response. This response, coordinated by central nervous system resident microglia and peripherally-derived infiltrating macrophages, has been shown to be important in the remyelination process. These innate immune cells perform important functions in remyelination, including the proteolysis and phagocytosis of inhibitory molecules present in the lesion microenvironment, the provision of trophic and metabolic factors to OPCs, in addition to iron handling capacity. Additionally, an initial pro-inflammatory phase followed by a regulatory/anti-inflammatory phase has been shown to be important for OPC proliferation and differentiation, respectively. This review will discuss the beneficial roles of macrophages/microglia in remyelination and discuss therapeutic strategies to obtain the optimal regenerative macrophage phenotype for enhanced remyelination.
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Affiliation(s)
- Khalil S Rawji
- Hotchkiss Brain Institute and the Department of Clinical Neurosciences, University of Calgary Calgary, AB, Canada
| | - Manoj K Mishra
- Hotchkiss Brain Institute and the Department of Clinical Neurosciences, University of Calgary Calgary, AB, Canada
| | - V Wee Yong
- Hotchkiss Brain Institute and the Department of Clinical Neurosciences, University of Calgary Calgary, AB, Canada
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26
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Goldstein EZ, Church JS, Hesp ZC, Popovich PG, McTigue DM. A silver lining of neuroinflammation: Beneficial effects on myelination. Exp Neurol 2016; 283:550-9. [PMID: 27151600 DOI: 10.1016/j.expneurol.2016.05.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 04/27/2016] [Accepted: 05/01/2016] [Indexed: 12/19/2022]
Abstract
Myelin accelerates action potential conduction velocity and provides essential energy support for axons. Unfortunately, myelin and myelinating cells are often vulnerable to injury or disease, resulting in myelin damage, which in turn can lead to axon dysfunction, overt pathology and neurological impairment. Inflammation is a common component of trauma and disease in both the CNS and PNS and therefore an active inflammatory response is often considered deleterious to myelin health. While inflammation can certainly damage myelin, inflammatory processes also can positively affect oligodendrocyte lineage progression, myelin debris clearance, oligodendrocyte metabolism and myelin repair. In the periphery, inflammatory cascades can also augment myelin repair, including processes initiated by infiltrating immune cells as well as by local Schwann cells. In this review, various aspects of inflammation beneficial to myelin repair are discussed and should be considered when designing or implementing anti-inflammatory therapies for CNS and PNS injury involving myelinating cells.
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Affiliation(s)
- Evan Z Goldstein
- Neuroscience Graduate Program, Wexner Medical Center, The Ohio State University, United States; Center for Brain and Spinal Cord Repair, Wexner Medical Center, The Ohio State University, United States
| | - Jamie S Church
- Neuroscience Graduate Program, Wexner Medical Center, The Ohio State University, United States; Center for Brain and Spinal Cord Repair, Wexner Medical Center, The Ohio State University, United States
| | - Zoe C Hesp
- Neuroscience Graduate Program, Wexner Medical Center, The Ohio State University, United States; Center for Brain and Spinal Cord Repair, Wexner Medical Center, The Ohio State University, United States
| | - Phillip G Popovich
- Department of Neuroscience, Wexner Medical Center, The Ohio State University, United States; Center for Brain and Spinal Cord Repair, Wexner Medical Center, The Ohio State University, United States
| | - Dana M McTigue
- Department of Neuroscience, Wexner Medical Center, The Ohio State University, United States; Center for Brain and Spinal Cord Repair, Wexner Medical Center, The Ohio State University, United States.
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27
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Grishchuk Y, Peña KA, Coblentz J, King VE, Humphrey DM, Wang SL, Kiselyov KI, Slaugenhaupt SA. Impaired myelination and reduced brain ferric iron in the mouse model of mucolipidosis IV. Dis Model Mech 2015; 8:1591-601. [PMID: 26398942 PMCID: PMC4728313 DOI: 10.1242/dmm.021154] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 09/08/2015] [Indexed: 12/11/2022] Open
Abstract
Mucolipidosis type IV (MLIV) is a lysosomal storage disease caused by mutations in the MCOLN1 gene, which encodes the lysosomal transient receptor potential ion channel mucolipin-1 (TRPML1). MLIV causes impaired motor and cognitive development, progressive loss of vision and gastric achlorhydria. How loss of TRPML1 leads to severe psychomotor retardation is currently unknown, and there is no therapy for MLIV. White matter abnormalities and a hypoplastic corpus callosum are the major hallmarks of MLIV brain pathology. Here, we report that loss of TRPML1 in mice results in developmental aberrations of brain myelination as a result of deficient maturation and loss of oligodendrocytes. Defective myelination is evident in Mcoln1(-/-) mice at postnatal day 10, an active stage of postnatal myelination in the mouse brain. Expression of mature oligodendrocyte markers is reduced in Mcoln1(-/-) mice at postnatal day 10 and remains lower throughout the course of the disease. We observed reduced Perls' staining in Mcoln1(-/-) brain, indicating lower levels of ferric iron. Total iron content in unperfused brain is not significantly different between Mcoln1(-/-) and wild-type littermate mice, suggesting that the observed maturation delay or loss of oligodendrocytes might be caused by impaired iron handling, rather than by global iron deficiency. Overall, these data emphasize a developmental rather than a degenerative disease course in MLIV, and suggest that there should be a stronger focus on oligodendrocyte maturation and survival to better understand MLIV pathogenesis and aid treatment development.
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Affiliation(s)
- Yulia Grishchuk
- Center for Human Genetic Research and Department of Neurology, Massachusetts General Hospital and Harvard Medical School, 185 Cambridge Street, Boston, MA 02114, USA
| | - Karina A Peña
- Department of Biological Sciences, University of Pittsburgh, 519 Langley Hall, 4249 Fifth Avenue, Pittsburgh, PA 15260, USA
| | - Jessica Coblentz
- Department of Biological Sciences, University of Pittsburgh, 519 Langley Hall, 4249 Fifth Avenue, Pittsburgh, PA 15260, USA
| | - Victoria E King
- Center for Human Genetic Research and Department of Neurology, Massachusetts General Hospital and Harvard Medical School, 185 Cambridge Street, Boston, MA 02114, USA
| | - Daniel M Humphrey
- Center for Human Genetic Research and Department of Neurology, Massachusetts General Hospital and Harvard Medical School, 185 Cambridge Street, Boston, MA 02114, USA
| | - Shirley L Wang
- Center for Human Genetic Research and Department of Neurology, Massachusetts General Hospital and Harvard Medical School, 185 Cambridge Street, Boston, MA 02114, USA
| | - Kirill I Kiselyov
- Department of Biological Sciences, University of Pittsburgh, 519 Langley Hall, 4249 Fifth Avenue, Pittsburgh, PA 15260, USA
| | - Susan A Slaugenhaupt
- Center for Human Genetic Research and Department of Neurology, Massachusetts General Hospital and Harvard Medical School, 185 Cambridge Street, Boston, MA 02114, USA
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28
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Leitner DF, Todorich B, Zhang X, Connor JR. Semaphorin4A Is Cytotoxic to Oligodendrocytes and Is Elevated in Microglia and Multiple Sclerosis. ASN Neuro 2015; 7:7/3/1759091415587502. [PMID: 26024919 PMCID: PMC4449839 DOI: 10.1177/1759091415587502] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
We have previously established that T cell immunoglobulin and mucin domain containing 2 (Tim2) is an H-ferritin receptor on oligodendrocytes (OLs). Tim2 also binds Semaphorin4A (Sema4A). Sema4A is expressed by lymphocytes, and its role in immune activation is known; however, its relationship to diseases that are known to have myelin damage has not been studied. In this study, we demonstrate that Sema4A is cytotoxic to OLs in culture: an effect accompanied by process collapse, membrane blebbing, and phosphatidylserine inversion. We further demonstrate that Sema4A preferentially binds to primary OLs but not astrocytes: an observation consistent with the lack of expression of Tim2 on astrocytes. We found that Sema4A protein levels are increased within multiple sclerosis plaques compared with normal-appearing white matter and that Sema4A induces lactate dehydrogenase release in a human OL cell line. The chief cellular source of Sema4A within the multiple sclerosis plaques appears to be infiltrating lymphocytes and microglia. Macrophages are known to express Sema4A, so we interrogated microglia as a potential source of Sema4A in the brain. We found that rat primary microglia express Sema4A which increased after lipopolysaccharide activation. Because activated microglia accumulate iron, we determined whether iron status influenced Sema4A and found that iron chelation decreased Sema4A and iron loading increased Sema4A in activated microglia. Overall, our data implicate Sema4A in the destruction of OLs and reveal that its expression is sensitive to iron levels.
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Affiliation(s)
- Dominique F Leitner
- Department of Neurosurgery, Penn State University College of Medicine, Hershey, PA, USA
| | - Bozho Todorich
- Duke Eye Center, Department of Ophthalmology, Duke University School of Medicine, Durham, NC, USA
| | - Xuesheng Zhang
- Department of Pediatrics, Penn State University College of Medicine, Hershey, PA, USA
| | - James R Connor
- Department of Neurosurgery, Penn State University College of Medicine, Hershey, PA, USA
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Novrup HG, Bracchi-Ricard V, Ellman DG, Ricard J, Jain A, Runko E, Lyck L, Yli-Karjanmaa M, Szymkowski DE, Pearse DD, Lambertsen KL, Bethea JR. Central but not systemic administration of XPro1595 is therapeutic following moderate spinal cord injury in mice. J Neuroinflammation 2014; 11:159. [PMID: 25204558 PMCID: PMC4176557 DOI: 10.1186/s12974-014-0159-6] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 08/23/2014] [Indexed: 12/27/2022] Open
Abstract
Background Glial cell activation and overproduction of inflammatory mediators in the central nervous system (CNS) have been implicated in acute traumatic injuries to the CNS, including spinal cord injury (SCI). Elevated levels of the proinflammatory cytokine tumor necrosis factor (TNF), which exists in both a soluble (sol) and a transmembrane (tm) form, have been found in the lesioned cord early after injury. The contribution of solTNF versus tmTNF to the development of the lesion is, however, still unclear. Methods We tested the effect of systemically or centrally blocking solTNF alone, using XPro1595, versus using the drug etanercept to block both solTNF and tmTNF compared to a placebo vehicle following moderate SCI in mice. Functional outcomes were evaluated using the Basso Mouse Scale, rung walk test, and thermal hyperalgesia analysis. The inflammatory response in the lesioned cord was investigated using immunohistochemistry and western blotting analyses. Results We found that peripheral administration of anti-TNF therapies had no discernable effect on locomotor performances after SCI. In contrast, central administration of XPro1595 resulted in improved locomotor function, decreased anxiety-related behavior, and reduced damage to the lesioned spinal cord, whereas central administration of etanercept had no therapeutic effects. Improvements in XPro1595-treated mice were accompanied by increases in Toll-like receptor 4 and TNF receptor 2 (TNFR2) protein levels and changes in Iba1 protein expression in microglia/macrophages 7 and 28 days after SCI. Conclusions These studies suggest that, by selectively blocking solTNF, XPro1595 is neuroprotective when applied directly to the lesioned cord. This protection may be mediated via alteration of the inflammatory environment without suppression of the neuroprotective effects of tmTNF signaling through TNFR2.
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Affiliation(s)
- Hans G Novrup
- Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, J.B. Winsloewsvej 21 St, 5000, Odense C, Denmark.
| | - Valerie Bracchi-Ricard
- Department of Neurological Surgery, The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, 1095 NW 14th Ter R-48, Miami, FL, 33136, USA.
| | - Ditte G Ellman
- Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, J.B. Winsloewsvej 21 St, 5000, Odense C, Denmark.
| | - Jerome Ricard
- Department of Neurological Surgery, The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, 1095 NW 14th Ter R-48, Miami, FL, 33136, USA.
| | - Anjana Jain
- Department of Neurological Surgery, The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, 1095 NW 14th Ter R-48, Miami, FL, 33136, USA. .,Department of Biomedical Engineering, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA, 01609-2280, USA.
| | - Erik Runko
- Department of Neurological Surgery, The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, 1095 NW 14th Ter R-48, Miami, FL, 33136, USA.
| | - Lise Lyck
- Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, J.B. Winsloewsvej 21 St, 5000, Odense C, Denmark. .,Coloplast A/S, Holtedam 1, 3050, Humlebæk, Denmark, Denmark.
| | - Minna Yli-Karjanmaa
- Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, J.B. Winsloewsvej 21 St, 5000, Odense C, Denmark.
| | | | - Damien D Pearse
- Department of Neurological Surgery, The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, 1095 NW 14th Ter R-48, Miami, FL, 33136, USA.
| | - Kate L Lambertsen
- Department of Neurological Surgery, The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, 1095 NW 14th Ter R-48, Miami, FL, 33136, USA. .,Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, J.B. Winsloewsvej 21 St, 5000, Odense C, Denmark.
| | - John R Bethea
- Department of Neurological Surgery, The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, 1095 NW 14th Ter R-48, Miami, FL, 33136, USA. .,Department of Biology, Drexel University, 3245 Chestnut St., PISB 123, Philadelphia, PA, 19104, USA.
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Stephenson E, Nathoo N, Mahjoub Y, Dunn JF, Yong VW. Iron in multiple sclerosis: roles in neurodegeneration and repair. Nat Rev Neurol 2014; 10:459-68. [PMID: 25002107 DOI: 10.1038/nrneurol.2014.118] [Citation(s) in RCA: 163] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
MRI and histological studies have shown global alterations in iron levels in the brains of patients with multiple sclerosis (MS), including increases in the iron stored by macrophages and microglia. Excessive free iron can be toxic, and accumulation of iron in MS has generally been thought to be detrimental. However, iron maintains the integrity of oligodendrocytes and myelin, and facilitates their regeneration following injury. The extracellular matrix, a key regulator of remyelination, might also modulate iron levels. This Review highlights key histological and MRI studies that have investigated changes in iron distribution associated with MS. Potential sources of iron, as well as iron regulatory proteins and the detrimental roles of excessive iron within the CNS, are also discussed, with emphasis on the importance of iron within cells for oxidative metabolism, proliferation and differentiation of oligodendrocytes, and myelination. In light of the beneficial and detrimental properties of iron within the CNS, we present considerations for treatments that target iron in MS. Such treatments must balance trophic and toxic properties of iron, by providing sufficient iron levels for remyelination and repair while avoiding excesses that might overwhelm homeostatic mechanisms and contribute to damage.
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Affiliation(s)
- Erin Stephenson
- Hotchkiss Brain Institute and the Department of Clinical Neurosciences, University of Calgary, Health Medical Research Centre, Room 187, 3330 Hospital Drive NW, Calgary, AB T2N 4N1, Canada
| | - Nabeela Nathoo
- Hotchkiss Brain Institute and the Department of Clinical Neurosciences, University of Calgary, Health Medical Research Centre, Room 187, 3330 Hospital Drive NW, Calgary, AB T2N 4N1, Canada
| | - Yasamin Mahjoub
- Hotchkiss Brain Institute and the Department of Clinical Neurosciences, University of Calgary, Health Medical Research Centre, Room 187, 3330 Hospital Drive NW, Calgary, AB T2N 4N1, Canada
| | - Jeff F Dunn
- Hotchkiss Brain Institute and the Department of Clinical Neurosciences, University of Calgary, Health Medical Research Centre, Room 187, 3330 Hospital Drive NW, Calgary, AB T2N 4N1, Canada
| | - V Wee Yong
- Hotchkiss Brain Institute and the Department of Clinical Neurosciences, University of Calgary, Health Medical Research Centre, Room 187, 3330 Hospital Drive NW, Calgary, AB T2N 4N1, Canada
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Sahinkaya FR, Milich LM, McTigue DM. Changes in NG2 cells and oligodendrocytes in a new model of intraspinal hemorrhage. Exp Neurol 2014; 255:113-26. [PMID: 24631375 DOI: 10.1016/j.expneurol.2014.02.025] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 02/18/2014] [Accepted: 02/22/2014] [Indexed: 02/04/2023]
Abstract
Spinal cord injury (SCI) evokes rapid deleterious and reparative glial reactions. Understanding the triggers for these responses is necessary for designing strategies to maximize repair. This study examined lesion formation and glial responses to vascular disruption and hemorrhage, a prominent feature of acute SCI. The specific role of hemorrhage is difficult to evaluate in trauma-induced lesions, because mechanical injury initiates many downstream responses. To isolate vascular disruption from trauma-induced effects, we created a novel and reproducible model of collagenase-induced intraspinal hemorrhage (ISH) and compared glial reactions between unilateral ISH and a hemi-contusion injury. Similar to contusion injuries, ISH lesions caused loss of myelin and axons and became filled with iron-laden macrophages. We hypothesized that intraspinal hemorrhage would also initiate reparative cellular responses including NG2+ oligodendrocyte progenitor cell (OPC) proliferation and oligodendrocyte genesis. Indeed, ISH induced OPC proliferation within 1d post-injury (dpi), which continued throughout the first week and resulted in a sustained elevation of NG2+ OPCs. ISH also caused oligodendrocyte loss within 4h that was sustained through 3d post-ISH. However, oligodendrogenesis, as determined by bromo-deoxyuridine (BrdU) positive oligodendrocytes, restored oligodendrocyte numbers by 7dpi, revealing that proliferating OPCs differentiated into new oligodendrocytes after ISH. The signaling molecules pERK1/2 and pSTAT3 were robustly increased acutely after ISH, with pSTAT3 being expressed in a portion of OPCs, suggesting that activators of this signaling cascade may initiate OPC responses. Aside from subtle differences in timing of OPC responses, changes in ISH tissue closely mimicked those in hemi-contusion tissue. These results are important for elucidating the contribution of hemorrhage to lesion formation and endogenous cell-mediated repair, and will provide the foundation for future studies geared toward identifying the role of specific blood components on injury and repair mechanisms. This understanding may provide new clinical targets for SCI and other devastating conditions such as intracerebral hemorrhage.
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Affiliation(s)
- F Rezan Sahinkaya
- Department of Neuroscience, Ohio State University, Columbus, OH 43210, USA; Neuroscience Graduate Studies Program, Ohio State University, Columbus, OH 43210, USA; Center for Brain and Spinal Cord Repair, Ohio State University, Columbus, OH 43210, USA
| | - Lindsay M Milich
- Center for Brain and Spinal Cord Repair, Ohio State University, Columbus, OH 43210, USA
| | - Dana M McTigue
- Department of Neuroscience, Ohio State University, Columbus, OH 43210, USA; Center for Brain and Spinal Cord Repair, Ohio State University, Columbus, OH 43210, USA.
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Abstract
AbstractGlia, including astrocytes, microglia and oligodendrocytes, are important components that maintain the architecture of the brain and in many ways contribute to the proper functioning of neurons. Glial cells vastly outnumber neurons in the brain and independently control several crucial brain functions. Impaired glial cells are the cause of several diseases, and pharmacological targeting to repair damaged glia will enable functional recovery in patients suffering from devastating neurological disorders. The interaction between glial cells and some patrolling immune cells in the brain comprise the brain-specific immune system that protects the brain from extraneous agents and repairs injured tissue. While this system can cope with minor insults and infections, when faced with significant challenges such as AIDS dementia, multiple sclerosis, Huntington’s disease, Parkinson’s disease, etc., an effective and balanced immune response that facilitates repair and protection is found wanting. Several debilitating neurological disorders are often associated with dysfunctional glial cells that have limited ability to repair the injured brain and even promote brain damage. In this discussion, specific signaling pathways in glia that are affected in AIDS dementia and periventricular white matter injury will be highlighted.
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Clemente D, Ortega MC, Melero-Jerez C, de Castro F. The effect of glia-glia interactions on oligodendrocyte precursor cell biology during development and in demyelinating diseases. Front Cell Neurosci 2013; 7:268. [PMID: 24391545 PMCID: PMC3868919 DOI: 10.3389/fncel.2013.00268] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2013] [Accepted: 12/03/2013] [Indexed: 01/12/2023] Open
Abstract
Oligodendrocyte precursor cells (OPCs) originate in specific areas of the developing central nervous system (CNS). Once generated, they migrate towards their destinations where they differentiate into mature oligodendrocytes. In the adult, 5-8% of all cells in the CNS are OPCs, cells that retain the capacity to proliferate, migrate, and differentiate into oligodendrocytes. Indeed, these endogenous OPCs react to damage in demyelinating diseases, like multiple sclerosis (MS), representing a key element in spontaneous remyelination. In the present work, we review the specific interactions between OPCs and other glial cells (astrocytes, microglia) during CNS development and in the pathological scenario of MS. We focus on: (i) the role of astrocytes in maintaining the homeostasis and spatial distribution of different secreted cues that determine OPC proliferation, migration, and differentiation during CNS development; (ii) the role of microglia and astrocytes in the redistribution of iron, which is crucial for myelin synthesis during CNS development and for myelin repair in MS; (iii) how microglia secrete different molecules, e.g., growth factors, that favor the recruitment of OPCs in acute phases of MS lesions; and (iv) how astrocytes modify the extracellular matrix in MS lesions, affecting the ability of OPCs to attempt spontaneous remyelination. Together, these issues demonstrate how both astroglia and microglia influence OPCs in physiological and pathological situations, reinforcing the concept that both development and neural repair are complex and global phenomena. Understanding the molecular and cellular mechanisms that control OPC survival, proliferation, migration, and differentiation during development, as well as in the mature CNS, may open new opportunities in the search for reparative therapies in demyelinating diseases like MS.
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Affiliation(s)
- Diego Clemente
- Grupo de Neurobiología del Desarrollo-GNDe, Hospital Nacional de Parapléjicos Toledo, Spain
| | - María Cristina Ortega
- Grupo de Neurobiología del Desarrollo-GNDe, Hospital Nacional de Parapléjicos Toledo, Spain
| | - Carolina Melero-Jerez
- Grupo de Neurobiología del Desarrollo-GNDe, Hospital Nacional de Parapléjicos Toledo, Spain
| | - Fernando de Castro
- Grupo de Neurobiología del Desarrollo-GNDe, Hospital Nacional de Parapléjicos Toledo, Spain
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Sauerbeck A, Schonberg DL, Laws JL, McTigue DM. Systemic iron chelation results in limited functional and histological recovery after traumatic spinal cord injury in rats. Exp Neurol 2013; 248:53-61. [PMID: 23712107 DOI: 10.1016/j.expneurol.2013.05.011] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Revised: 05/13/2013] [Accepted: 05/17/2013] [Indexed: 12/15/2022]
Abstract
Excess iron accumulation within the spinal cord is thought to exacerbate tissue damage and limit functional recovery after traumatic spinal cord injury (SCI). An optimal treatment to reverse or prevent damage would be to deliver an iron chelator systemically. Thus, we tested oral delivery of deferasirox (Exjade) in multiple studies using a rat model of mid-thoracic spinal contusion. Female Sprague-Dawley rats received a moderate contusion at vertebral level T8 and were given daily deferasirox for the first 7 or 14 days post-injury. The first two studies showed modest improvements in hindlimb function with limited improvement in tissue sparing. Two subsequent experiments to assess chronic functional changes and test longer-duration treatments failed to produce significant improvements. Testing a 2-fold higher deferasirox dose resulted in toxic side effects. To verify iron chelation treatment was effective, hepatic iron levels were measured which revealed that deferasirox robustly and significantly reduced systemic iron levels. Overall, this study suggests that oral iron chelation with deferasirox may lead to small but significant improvements in locomotor recovery or tissue sparing. However, given the lack of robust beneficial effects combined with potentially detrimental side effects such as exacerbated systemic anemia, oral administration of iron chelators may not be ideal for minimizing intraspinal iron-mediated pathology after SCI.
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Affiliation(s)
- Andrew Sauerbeck
- The Center for Brain and Spinal Cord Repair, The Ohio State University, Columbus, OH, USA; Department of Neuroscience, The Ohio State University, Columbus, OH, USA
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Silvestroff L, Franco P, Pasquini J. Neural and oligodendrocyte progenitor cells: transferrin effects on cell proliferation. ASN Neuro 2013; 5:e00107. [PMID: 23368675 PMCID: PMC3592559 DOI: 10.1042/an20120075] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Revised: 01/08/2013] [Accepted: 01/10/2013] [Indexed: 12/14/2022] Open
Abstract
NSC (neural stem cells)/NPC (neural progenitor cells) are multipotent and self-renew throughout adulthood in the SVZ (subventricular zone) of the mammalian CNS (central nervous system). These cells are considered interesting targets for CNS neurodegenerative disorder cell therapies, and understanding their behaviour in vitro is crucial if they are to be cultured prior to transplantation. We cultured the SVZ tissue belonging to newborn rats under the form of NS (neurospheres) to evaluate the effects of Tf (transferrin) on cell proliferation. The NS were heterogeneous in terms of the NSC/NPC markers GFAP (glial fibrillary acidic protein), Nestin and Sox2 and the OL (oligodendrocyte) progenitor markers NG2 (nerve/glia antigen 2) and PDGFRα (platelet-derived growth factor receptor α). The results of this study indicate that aTf (apoTransferrin) is able to increase cell proliferation of SVZ-derived cells in vitro, and that these effects were mediated at least in part by the TfRc1 (Tf receptor 1). Since OPCs (oligodendrocyte progenitor cells) represent a significant proportion of the proliferating cells in the SVZ-derived primary cultures, we used the immature OL cell line N20.1 to show that Tf was able to augment the proliferation rate of OPC, either by adding aTf to the culture medium or by overexpressing rat Tf in situ. The culture medium supplemented with ferric iron, together with aTf, increased the DNA content, while ferrous iron did not. The present work provides data that could have a potential application in human cell replacement therapies for neurodegenerative disease and/or CNS injury that require the use of in vitro amplified NPCs.
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Key Words
- nerve/glia antigen 2 (ng2)
- oligodendrocyte
- platelet-derived growth factor receptor α (pdgfrα)
- progenitor
- proliferation
- transferrin
- atf, apotransferrin
- bfgf, basic fibroblast growth factor
- brdu, bromodeoxyuridine
- cns, central nervous system
- csf, cerebrospinal fluid
- dmem, dulbecco’s modified eagle’s medium
- egf, epidermal growth factor
- fcs, fetal calf serum
- gfap, glial fibrillary acidic protein
- icc, immunocytochemistry
- ng2, nerve/glia antigen 2
- npc, neural progenitor cell
- ns, neurosphere
- nsc, neural stem cell
- ol, oligodendrocyte
- opc, oligodendrocyte progenitor cell
- os, oligosphere
- pdgfrα, platelet-derived growth factor receptor α
- pexptf, pexpresstf
- pfa, paraformaldehyde
- po, polyornithine
- rt–pcr, reverse transcription–pcr
- svz, subventricular zone
- tf, transferrin
- tfrc, tf receptor
- tf-tr, texas red-labelled tf
- wb, western blotting
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Affiliation(s)
- Lucas Silvestroff
- Cátedra de Química Biológica Patológica, Departamento de Química Biológica, Facultad de Farmacia y Bioquímica (FFyB), Universidad de Buenos Aires (UBA), Buenos Aires, Argentina
| | - Paula Gabriela Franco
- Cátedra de Química Biológica Patológica, Departamento de Química Biológica, Facultad de Farmacia y Bioquímica (FFyB), Universidad de Buenos Aires (UBA), Buenos Aires, Argentina
| | - Juana María Pasquini
- Cátedra de Química Biológica Patológica, Departamento de Química Biológica, Facultad de Farmacia y Bioquímica (FFyB), Universidad de Buenos Aires (UBA), Buenos Aires, Argentina
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Blomster LV, Cowin GJ, Kurniawan ND, Ruitenberg MJ. Detection of endogenous iron deposits in the injured mouse spinal cord through high-resolution ex vivo and in vivo MRI. NMR IN BIOMEDICINE 2013; 26:141-150. [PMID: 22730180 DOI: 10.1002/nbm.2829] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Revised: 05/07/2012] [Accepted: 05/25/2012] [Indexed: 06/01/2023]
Abstract
The main aim of this study was to employ high-resolution MRI to investigate the spatiotemporal development of pathological features associated with contusive spinal cord injury (SCI) in mice. Experimental mice were subjected to either sham surgery or moderate contusive SCI. A 16.4-T small-animal MR system was employed for nondestructive imaging of post-mortem, fixed spinal cord specimens at the subacute (7 days) and more chronic (28-35 days) stages post-injury. Routine histological techniques were used for subsequent investigation of the observed neuropathology at the microscopic level. The central core of the lesion appeared as a dark hypo-intense area on MR images at all time points investigated. Small focal hypo-intense spots were also observed spreading through the dorsal funiculi proximal and distal to the site of impact, an area that is known to undergo gliosis and Wallerian degeneration in response to injury. Histological examination revealed these hypo-intense spots to be high in iron content as determined by Prussian blue staining. Quantitative image analysis confirmed the increased presence of iron deposits at all post-injury time points investigated (p<0.05). Distant iron deposits were also detectable through live imaging without the use of contrast-enhancing agents, enabling the longitudinal investigation of this pathology in individual animals. Further immunohistochemical evaluation showed that intracellular iron deposits localised to macrophages/microglia, astrocytes and oligodendrocytes in the subacute phase of SCI, but predominantly to glial fibrillary acidic protein-positive, CC-1-positive astrocytes at later stages of recovery. Progressive, widespread intracellular iron accumulation is thus a normal feature of SCI in mice, and high-resolution MRI can be effectively used to detect and monitor these neuropathological changes with time.
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Affiliation(s)
- Linda V Blomster
- University of Queensland, School of Biomedical Sciences, St Lucia, Qld, Australia
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Kupershmidt L, Amit T, Bar-Am O, Youdim MBH, Weinreb O. The novel multi-target iron chelating-radical scavenging compound M30 possesses beneficial effects on major hallmarks of Alzheimer's disease. Antioxid Redox Signal 2012; 17:860-77. [PMID: 22360429 DOI: 10.1089/ars.2011.4279] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
AIMS The aim of the present study was to evaluate the therapeutic effect of the novel neuroprotective multi-target nontoxic, lipophilic, brain permeable monoamine oxidase inhibitor and iron chelating-radical scavenging drug, M30, on the neuropathology and deficits of spatial learning and memory in amyloid precursor protein (APP) and presenilin 1 (PS1) double-transgenic (Tg) Alzheimer's disease (AD) mice. RESULTS Here, we report that systemic treatment of APP/PS1 Tg mice with M30 for 9 months, significantly attenuated cognitive impairments in a variety of tasks of spatial learning and memory retention, working memory, learning abilities, anxiety levels, and memory for novel food and nesting behavior. Furthermore, we found that M30 reduced cerebral iron accumulation accompanied by a marked decrease in several AD-like phenotypes, including cerebral APP levels, amyloid β (Aβ) levels and plaques, phospho-APP and phospho-tau. Signaling studies revealed that M30 markedly downregulated the levels of phosphorylated cyclin-dependent kinase 5 and increased protein kinase B and glycogen synthase kinase 3β phosphorylation. INNOVATION Accumulation and deposition of brain iron is central to various neuropathological processes in AD, including oxidative stress, amyloid deposition, and tau phosphorylation. Thus, the concept of iron chelation holds considerable promise as a therapeutic strategy for AD pathogenesis. Here, for the first time, we demonstrated that, when systemically administered to APP/PS1 Tg mice, our novel multifunctional iron chelating/radical scavenging compound, M30, effectively reduced Aβ accumulation and tau phosphorylation, and attenuated memory deficits. CONCLUSIONS These findings suggest that M30 is a potential therapeutic agent for the prevention and treatment of AD.
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Affiliation(s)
- Lana Kupershmidt
- Eve Topf and USA National Parkinson Foundation Centers of Excellence for Neurodegenerative Diseases Research, Haifa, Israel
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Ferritin stimulates oligodendrocyte genesis in the adult spinal cord and can be transferred from macrophages to NG2 cells in vivo. J Neurosci 2012; 32:5374-84. [PMID: 22514302 DOI: 10.1523/jneurosci.3517-11.2012] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Injured CNS tissue often contains elevated iron and its storage protein ferritin, which may exacerbate tissue damage through pro-oxidative mechanisms. Therefore, therapeutic studies often target iron reduction as a neuroprotective strategy. However, iron may be crucial for oligodendrocyte replacement and remyelination. For instance, we previously showed that intraspinal toll-like receptor 4 macrophage activation induced the generation of new ferritin-positive oligodendrocytes, and that iron chelation significantly reduced this oligodendrogenic response. Since macrophages can secrete ferritin, we hypothesize that ferritin is a macrophage-derived signal that promotes oligodendrogenesis. To test this, we microinjected ferritin into intact adult rat spinal cords. Within 6 h, NG2+ progenitor cells proliferated and accumulated ferritin. By 3 d, many of these cells had differentiated into new oligodendrocytes. However, acute neuron and oligodendrocyte toxicity occurred in gray matter. Interestingly, ferritin-positive NG2 cells and macrophages accumulated in the area of cell loss, revealing that NG2 cells thrive in an environment that is toxic to other CNS cells. To test whether ferritin can be transferred from macrophages to NG2 cells in vivo, we loaded macrophages with fluorescent ferritin then transplanted them into intact spinal white matter. Within 3-6 d, proliferating NG2 cells migrated into the macrophage transplants and accumulated fluorescently labeled ferritin. These results show that activated macrophages can be an in vivo source of ferritin for NG2 cells, which induces their proliferation and differentiation into new oligodendrocytes. This work has relevance for conditions in which iron-mediated injury and/or repair likely occur, such as hemorrhage, stroke, spinal cord injury, aging, Parkinson's disease, and Alzheimer's disease.
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Abstract
How iron is delivered to the CNS for myelination is not well understood. We assessed whether astrocytes can provide iron to cells in the CNS for remyelination. To study this we generated a conditional deletion of the iron efflux transporter ferroportin (Fpn) in astrocytes, and induced focal demyelination in the mouse spinal cord dorsal column by microinjection of lysophosphatidylcholine (LPC). Remyelination assessed by electron microscopy was reduced in astrocyte-specific Fpn knock-out mice compared with wild-type controls, as was proliferation of oligodendrocyte precursor cells (OPCs). Cell culture work showed that lack of iron reduces the ability of microglia to express cytokines (TNF-α and IL-1β) involved in remyelination. Furthermore, astrocytes in culture express high levels of FGF-2 in response to IL-1β, and IGF-1 in response to TNF-α stimulation. FGF-2 and IGF-1 are known to be important for myelination. Reduction in IL-1β and IGF-1 were also seen in astrocyte-specific Fpn knock-out mice after LPC-induced demyelination. These data suggest that iron efflux from astrocytes plays a role in remyelination by either direct effects on OPCs or indirectly by affecting glial activation.
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Iron dysregulation in movement disorders. Neurobiol Dis 2012; 46:1-18. [DOI: 10.1016/j.nbd.2011.12.054] [Citation(s) in RCA: 127] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Revised: 12/22/2011] [Accepted: 12/31/2011] [Indexed: 01/04/2023] Open
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Oliva SU, Scarano WR, Okada FK, Miraglia SM. Harmful effects of carbamazepine on the postnatal development of the rat ventral prostate. Reprod Biol Endocrinol 2012; 10:22. [PMID: 22443633 PMCID: PMC3344685 DOI: 10.1186/1477-7827-10-22] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Accepted: 03/25/2012] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Carbamazepine (CBZ) is a first-line antiepileptic drug (AED), although it is also used for the treatments of psychiatric disorders and neuropathic pain. The CBZ utilization has been associated with male reproductive damage, including hormonal alterations, sexual dysfunction and reduction of sperm quality. The wide and long-term use of the CBZ is a common schedule in children and adolescents and alters the testosterone level in adult rats and humans. The objective of this work was to evaluate the CBZ side effects on the ventral prostate of rats from pre-puberty to sexual maturation, since the prostate is an androgen-dependent organ. METHODS Twenty three day-old male albino Wistar rats received CBZ diluted in propylene glycol (20 mg/Kg/i.p via). The treatment lasted 20, 40 and 70 days, according to the different stages of the rat sexual maturation. At the end of each treatment period, ventral prostates were removed and histologically processed. The prostate sections were submitted to the histopathological, morphological and stereological analyses using image analysis system. RESULTS Reductions of the glandular epithelium, glandular lumen and fibromuscular stroma volume of the ventral prostate were observed in adult rats treated with CBZ since the weaning. Triggering and degranulation of mast cells were observed in the fibromuscular stroma of prepubertal and pubertal CBZ treated rats. CONCLUSIONS The results suggest a direct effect of the CBZ on rat ventral prostate, evidenced by increase of mast cell and macrophage populations during pre-puberty and puberty causing a ventral prostate accentuated damage in the adult phase.
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Affiliation(s)
- Samara U Oliva
- Department of Morphology and Genetics, Developmental Biology Laboratory, Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil
| | - Wellerson R Scarano
- Department of Morphology, São Paulo State University (UNESP), Botucatu, SP, Brazil
| | - Fatima K Okada
- Department of Morphology and Genetics, Developmental Biology Laboratory, Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil
| | - Sandra M Miraglia
- Department of Morphology and Genetics, Developmental Biology Laboratory, Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil
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Rathore KI, Redensek A, David S. Iron homeostasis in astrocytes and microglia is differentially regulated by TNF-α and TGF-β1. Glia 2012; 60:738-50. [PMID: 22298416 DOI: 10.1002/glia.22303] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Revised: 12/21/2011] [Accepted: 01/12/2012] [Indexed: 11/07/2022]
Abstract
Abnormal iron homeostasis is increasingly thought to contribute to the pathogenesis of several neurodegenerative disorders. We have previously reported impaired iron homeostasis in a mouse model of spinal cord injury and in a mouse model of amyotrophic lateral sclerosis. Both these disorders are associated with CNS inflammation. However, what effect inflammation, and in particular, inflammatory cytokines have on iron homeostasis in CNS glia remains largely unknown. Here we report that the proinflammatory cytokine TNF-α, and the anti-inflammatory cytokine TGF-β1 affect iron homeostasis in astrocytes and microglia in distinct ways. Treatment of astrocytes in vitro with TNF-α induced the expression of the iron importer "divalent iron transporter 1" (DMT1) and suppressed the expression of the iron exporter ferroportin (FPN). However, TGF-β1 had no effect on DMT1 expression but increased the expression of FPN in astrocytes. In microglia, on the other hand, both cytokines caused induction of DMT1 and suppression of FPN expression. Iron influx and efflux assays in vitro confirmed that iron homeostasis in astrocytes and microglia is differentially regulated by these cytokines. In particular, TNF-α caused an increase in iron uptake and retention by both astrocytes and microglia, while TGF-β1 promoted iron efflux from astrocytes but caused iron retention in microglia. These data suggest that these two cytokines, which are expressed in CNS inflammation in injury and disease, can have profound and divergent effects on iron homeostasis in astrocytes and microglia.
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Affiliation(s)
- Khizr I Rathore
- Center for Research in Neuroscience, The Research Institute of the McGill University Health Center, Montreal, Quebec, Canada
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Abstract
Accumulation of iron occurs in the CNS in several neurodegenerative diseases. Iron is essential for life but also has the ability to generate toxic free radicals if not properly handled. Iron homeostasis at the cellular level is therefore important to maintain proper cellular function, and its dysregulation can contribute to neurodegenerative diseases. Iron export, a key mechanism to maintain proper levels in cells, occurs via ferroportin, a ubiquitously expressed transmembrane protein that partners with a ferroxidase. A membrane-bound form of the ferroxidase ceruloplasmin is expressed by astrocytes in the CNS and regulates iron efflux. We now show that oligodendrocytes use another ferroxidase, called hephaestin, which was first identified in enterocytes in the gut. Mice with mutations in the hephaestin gene (sex-linked anemia mice) show iron accumulation in oligodendrocytes in the gray matter, but not in the white matter, and exhibit motor deficits. This was accompanied by a marked reduction in the levels of the paranodal proteins contactin-associated protein 1 (Caspr) and reticulon-4 (Nogo A). We show that the sparing of iron accumulation in white matter oligodendrocytes in sex-linked anemia mice is due to compensatory upregulation of ceruloplasmin in these cells. This was further confirmed in ceruloplasmin/hephaestin double-mutant mice, which show iron accumulation in both gray and white matter oligodendrocytes. These data indicate that gray and white matter oligodendrocytes can use different iron efflux mechanisms to maintain iron homeostasis. Dysregulation of such efflux mechanisms leads to iron accumulation in the CNS.
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Tota M, Jakovac H, Grebić D, Marinić J, Broznić D, Čanadi-Jurešić G, Milin C, Radošević-Stašić B. Kinetics of tissue iron in experimental autoimmune encephalomyelitis in rats. Biol Trace Elem Res 2011; 143:332-43. [PMID: 20845085 DOI: 10.1007/s12011-010-8841-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2010] [Accepted: 09/02/2010] [Indexed: 10/19/2022]
Abstract
To elucidate the role of iron in the pathomechanisms of autoimmune CNS disorders, we estimated the tissue concentrations of Fe(2+) in the brain, spinal cord, and liver in the chronic relapsing form of experimental autoimmune encephalomyelitis (EAE). The disease was induced in Dark Agouti (DA) strain of rats, by subcutaneous injection of bovine brain homogenate in complete Freund's adjuvant (CFA). Control rats consisted of unsensitized rats and of rats treated with CFA or saline. The data obtained by clinical assessment and by inductively coupled plasma spectrometry have shown that the attacks of disease (on the 12th and 22nd post-immunization day) were followed by high accumulation of iron in the liver. Additionally, during the second attack of disease, the decreased concentration of Fe(2+) was found in cervical spinal cord. The data point to regulatory effects of iron and hepatic trace elements regulating mechanisms in the pathogenesis of EAE.
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Affiliation(s)
- Marin Tota
- Department of Chemistry and Biochemistry, Medical Faculty, University of Rijeka, B Branchetta 22, 51 000 Rijeka, Croatia
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Abstract
Oligodendrocytes (OLs) are particularly susceptible to the toxicity of the acute lesion environment after spinal cord injury (SCI). They undergo both necrosis and apoptosis acutely, with apoptosis continuing at chronic time points. Loss of OLs causes demyelination and impairs axon function and survival. In parallel, a rapid and protracted OL progenitor cell proliferative response occurs, especially at the lesion borders. Proliferating and migrating OL progenitor cells differentiate into myelinating OLs, which remyelinate demyelinated axons starting at 2 weeks post-injury. The progression of OL lineage cells into mature OLs in the adult after injury recapitulates development to some degree, owing to the plethora of factors within the injury milieu. Although robust, this endogenous oligogenic response is insufficient against OL loss and demyelination. First, in this review we analyze the major spatial-temporal mechanisms of OL loss, replacement, and myelination, with the purpose of highlighting potential areas of intervention after SCI. We then discuss studies on OL protection and replacement. Growth factors have been used both to boost the endogenous progenitor response, and in conjunction with progenitor transplantation to facilitate survival and OL fate. Considerable progress has been made with embryonic stem cell-derived cells and adult neural progenitor cells. For therapies targeting oligogenesis to be successful, endogenous responses and the effects of the acute and chronic lesion environment on OL lineage cells must be understood in detail, and in relation, the optimal therapeutic window for such strategies must also be determined.
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Affiliation(s)
- Akshata Almad
- Neuroscience Graduate Studies Program, Ohio State University, Columbus, Ohio 43210 USA
- Center for Brain and Spinal Cord Repair, Ohio State University, Columbus, Ohio 43210 USA
| | - F. Rezan Sahinkaya
- Neuroscience Graduate Studies Program, Ohio State University, Columbus, Ohio 43210 USA
- Center for Brain and Spinal Cord Repair, Ohio State University, Columbus, Ohio 43210 USA
| | - Dana M. McTigue
- Center for Brain and Spinal Cord Repair, Ohio State University, Columbus, Ohio 43210 USA
- Department of Neuroscience, Ohio State University, 788 Biomedical Research Tower, 460 W. 12th Ave, Columbus, Ohio 43210 USA
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Todorich B, Zhang X, Connor JR. H-ferritin is the major source of iron for oligodendrocytes. Glia 2011; 59:927-35. [DOI: 10.1002/glia.21164] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2010] [Accepted: 01/31/2011] [Indexed: 12/14/2022]
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A possible role for secreted ferritin in tissue iron distribution. J Neural Transm (Vienna) 2011; 118:337-47. [PMID: 21298454 DOI: 10.1007/s00702-011-0582-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Accepted: 01/09/2011] [Indexed: 01/19/2023]
Abstract
Ferritin is known as a well-conserved iron detoxification and storage protein that is found in the cytosol of many prokaryotic and eukaryotic organisms. In insects and worms, ferritin has evolved into a classically secreted protein that transports iron systemically. Mammalian ferritins are found intracellularly in the cytosol, as well as in the nucleus, the endo-lysosomal compartment and the mitochondria. Extracellular ferritin is found in fluids such as serum and synovial and cerebrospinal fluids. We recently characterized the biophysical properties, secretion mechanism and cellular origin of mouse serum ferritin, which is actively secreted by a non-classical pathway involving lysosomal processing. Here, we review the data to support a hypothesis that intracellular and extracellular ferritin may play a role in intra- and intercellular redistribution of iron.
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Effects of Iron Chelators, Iron Salts, and Iron Oxide Nanoparticles on the Proliferation and the Iron Content of Oligodendroglial OLN-93 Cells. Neurochem Res 2010; 35:1259-68. [DOI: 10.1007/s11064-010-0184-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/26/2010] [Indexed: 12/19/2022]
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