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Chiareli RA, Carvalho GA, Marques BL, Mota LS, Oliveira-Lima OC, Gomes RM, Birbrair A, Gomez RS, Simão F, Klempin F, Leist M, Pinto MCX. The Role of Astrocytes in the Neurorepair Process. Front Cell Dev Biol 2021; 9:665795. [PMID: 34113618 PMCID: PMC8186445 DOI: 10.3389/fcell.2021.665795] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 04/29/2021] [Indexed: 12/17/2022] Open
Abstract
Astrocytes are highly specialized glial cells responsible for trophic and metabolic support of neurons. They are associated to ionic homeostasis, the regulation of cerebral blood flow and metabolism, the modulation of synaptic activity by capturing and recycle of neurotransmitters and maintenance of the blood-brain barrier. During injuries and infections, astrocytes act in cerebral defense through heterogeneous and progressive changes in their gene expression, morphology, proliferative capacity, and function, which is known as reactive astrocytes. Thus, reactive astrocytes release several signaling molecules that modulates and contributes to the defense against injuries and infection in the central nervous system. Therefore, deciphering the complex signaling pathways of reactive astrocytes after brain damage can contribute to the neuroinflammation control and reveal new molecular targets to stimulate neurorepair process. In this review, we present the current knowledge about the role of astrocytes in brain damage and repair, highlighting the cellular and molecular bases involved in synaptogenesis and neurogenesis. In addition, we present new approaches to modulate the astrocytic activity and potentiates the neurorepair process after brain damage.
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Affiliation(s)
| | | | | | - Lennia Soares Mota
- Department of Pharmacology, Federal University of Goias, Goiânia, Brazil
| | | | | | - Alexander Birbrair
- Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Renato Santiago Gomez
- Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Fabrício Simão
- Research Division, Vascular Cell Biology, Joslin Diabetes Center and Harvard Medical School, Boston, MA, United States
| | | | - Marcel Leist
- Konstanz Research School Chemical Biology, University of Konstanz, Konstanz, Germany
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2
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Zheng Y, Han Z, Zhao H, Luo Y. MAPK: A Key Player in the Development and Progression of Stroke. CNS & NEUROLOGICAL DISORDERS-DRUG TARGETS 2020; 19:248-256. [PMID: 32533818 DOI: 10.2174/1871527319666200613223018] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 05/15/2020] [Accepted: 05/16/2020] [Indexed: 12/13/2022]
Abstract
Conclusion:
Stroke is a complex disease caused by genetic and environmental factors, and its etiological
mechanism has not been fully clarified yet, which brings great challenges to its effective prevention
and treatment. MAPK signaling pathway regulates gene expression of eukaryotic cells and basic cellular
processes such as cell proliferation, differentiation, migration, metabolism and apoptosis, which are
considered as therapeutic targets for many diseases. Up to now, mounting evidence has shown that
MAPK signaling pathway is involved in the pathogenesis and development of ischemic stroke. However,
the upstream kinase and downstream kinase of MAPK signaling pathway are complex and the
influencing factors are numerous, the exact role of MAPK signaling pathway in the pathogenesis of
ischemic stroke has not been fully elucidated. MAPK signaling molecules in different cell types in the
brain respond variously after stroke injury, therefore, the present review article is committed to summarizing
the pathological process of different cell types participating in stroke, discussed the mechanism
of MAPK participating in stroke. We further elucidated that MAPK signaling pathway molecules
can be used as therapeutic targets for stroke, thus promoting the prevention and treatment of stroke.
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Affiliation(s)
- Yangmin Zheng
- Institute of Cerebrovascular Disease Research and Department of Neurology, Xuanwu Hospital of Capital Medical University, Beijing, China
| | - Ziping Han
- Institute of Cerebrovascular Disease Research and Department of Neurology, Xuanwu Hospital of Capital Medical University, Beijing, China
| | - Haiping Zhao
- Institute of Cerebrovascular Disease Research and Department of Neurology, Xuanwu Hospital of Capital Medical University, Beijing, China
| | - Yumin Luo
- Institute of Cerebrovascular Disease Research and Department of Neurology, Xuanwu Hospital of Capital Medical University, Beijing, China
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3
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Noël G, Tham DKL, MacVicar BA, Moukhles H. Agrin plays a major role in the coalescence of the aquaporin-4 clusters induced by gamma-1-containing laminin. J Comp Neurol 2019; 528:407-418. [PMID: 31454080 DOI: 10.1002/cne.24763] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 07/13/2019] [Accepted: 08/22/2019] [Indexed: 01/06/2023]
Abstract
The basement membrane that seperates the endothelial cells and astrocytic endfeet that comprise the blood-brain barrier is rich in collagen, laminin, agrin, and perlecan. Previous studies have demonstrated that the proper recruitment of the water-permeable channel aquaporin-4 (AQP4) to astrocytic endfeet is dependent on interactions between laminin and the receptor dystroglycan. In this study, we conducted a deeper investigation into how the basement membrane might further regulate the expression, localization, and function of AQP4, using primary astrocytes as a model system. We found that treating these cells with laminin causes endogenous agrin to localize to the cell surface, where it co-clusters with β-dystroglycan (β-DG). Conversely, agrin sliencing profoundly disrupts β-DG clustering. As in the case of laminin111, Matrigel™, a complete basement membrane analog, also causes the clustering of AQP4 and β-DG. This clustering, whether induced by laminin111 or Matrigel™ is inhibited when the astrocytes are first incubated with an antibody against the γ1 subunit of laminin, suggesting that the latter is crucial to the process. Finally, we showed that laminin111 appears to negatively regulate AQP4-mediated water transport in astrocytes, suppressing the cell swelling that occurs following a hypoosmotic challenge. This suppression is abolished if DG expression is silenced, again demonstrating the central role of this receptor in relaying the effects of laminin.
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Affiliation(s)
- Geoffroy Noël
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Daniel Kai Long Tham
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Brian A MacVicar
- Department of Psychiatry, University of British Columbia, Vancouver, British Columbia, Canada
| | - Hakima Moukhles
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada
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4
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Wang X, Xuan W, Zhu ZY, Li Y, Zhu H, Zhu L, Fu DY, Yang LQ, Li PY, Yu WF. The evolving role of neuro-immune interaction in brain repair after cerebral ischemic stroke. CNS Neurosci Ther 2018; 24:1100-1114. [PMID: 30350341 DOI: 10.1111/cns.13077] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 09/23/2018] [Accepted: 09/25/2018] [Indexed: 12/13/2022] Open
Abstract
Stroke is the world's leading cause of disability with limited brain repair treatments which effectively improve long-term neurological deficits. The neuroinflammatory responses persist into the late repair phase of stroke and participate in all brain repair elements, including neurogenesis, angiogenesis, synaptogenesis, remyelination and axonal sprouting, shedding new light on post-stroke brain recovery. Resident brain glial cells, such as astrocytes not only contribute to neuroinflammation after stroke, but also secrete a wide range of trophic factors that can promote post-stroke brain repair. Alternatively, activated microglia, monocytes, and neutrophils in the innate immune system, traditionally considered as major damaging factors after stroke, have been suggested to be extensively involved in brain repair after stroke. The adaptive immune system may also have its bright side during the late regenerative phase, affecting the immune suppressive regulatory T cells and B cells. This review summarizes the recent findings in the evolving role of neuroinflammation in multiple post-stroke brain repair mechanisms and poses unanswered questions that may generate new directions for future research and give rise to novel therapeutic targets to improve stroke recovery.
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Affiliation(s)
- Xin Wang
- Department of Anesthesiology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
| | - Wei Xuan
- Department of Anesthesiology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
| | - Zi-Yu Zhu
- Department of Anesthesiology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
| | - Yan Li
- Department of Anesthesiology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
| | - Hao Zhu
- Department of Anesthesiology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
| | - Ling Zhu
- Department of Anesthesiology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
| | - Dan-Yun Fu
- Department of Anesthesiology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
| | - Li-Qun Yang
- Department of Anesthesiology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
| | - Pei-Ying Li
- Department of Anesthesiology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
| | - Wei-Feng Yu
- Department of Anesthesiology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
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5
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Royall DR, Al-Rubaye S, Bishnoi R, Palmer RF. Serum protein mediators of dementia and aging proper. Aging (Albany NY) 2016; 8:3241-3254. [PMID: 27922822 PMCID: PMC5270666 DOI: 10.18632/aging.101091] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 11/17/2016] [Indexed: 12/27/2022]
Abstract
The latent variable "δ" (for "dementia") appears to be uniquely responsible for the dementing aspects of cognitive impairment. Age, depressive symptoms, gender and the apolipoprotein E (APOE) ε4 allele are independently associated with δ. In this analysis, we explore serum proteins as potential mediators of age's specific association with δ in a large, ethnically diverse longitudinal cohort, the Texas Alzheimer's Research and Care Consortium (TARCC). 22 serum proteins were recognized as partial mediators of age's association with δ. These include Insulin-like Growth Factor-Binding Protein 2 (IGF-BP2), which we had previously associated with age-specific cognitive change, and both Pancreatic Polypeptide (PP) and von Willebrand Factor (vWF), previously associated with δ. Nine other δ-related proteins were not confirmed by this ethnicity adjusted analysis. Our findings suggest that age's association with the disabling fraction of cognitive performance is partially mediated by serum proteins, somatomedins and hormones. Those proteins may offer targets for the specific treatment of age-related effects on dementia severity and conversion risk.
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Affiliation(s)
- Donald R. Royall
- Department of Psychiatry, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
- Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
- Department of Family and Community Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
- South Texas Veterans’ Health System Audie L. Murphy Division GRECC, San Antonio, TX 78229, USA
| | - Safa Al-Rubaye
- Department of Psychiatry, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Ram Bishnoi
- Department of Psychiatry, The Medical College of Georgia, Augusta, GA 30912, USA
| | - Raymond F. Palmer
- Department of Family and Community Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
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6
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Acaz-Fonseca E, Avila-Rodriguez M, Garcia-Segura LM, Barreto GE. Regulation of astroglia by gonadal steroid hormones under physiological and pathological conditions. Prog Neurobiol 2016; 144:5-26. [DOI: 10.1016/j.pneurobio.2016.06.002] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 06/05/2016] [Indexed: 01/07/2023]
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7
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Liu Z, Chopp M. Astrocytes, therapeutic targets for neuroprotection and neurorestoration in ischemic stroke. Prog Neurobiol 2015; 144:103-20. [PMID: 26455456 DOI: 10.1016/j.pneurobio.2015.09.008] [Citation(s) in RCA: 401] [Impact Index Per Article: 44.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Revised: 08/06/2015] [Accepted: 09/05/2015] [Indexed: 01/04/2023]
Abstract
Astrocytes are the most abundant cell type within the central nervous system. They play essential roles in maintaining normal brain function, as they are a critical structural and functional part of the tripartite synapses and the neurovascular unit, and communicate with neurons, oligodendrocytes and endothelial cells. After an ischemic stroke, astrocytes perform multiple functions both detrimental and beneficial, for neuronal survival during the acute phase. Aspects of the astrocytic inflammatory response to stroke may aggravate the ischemic lesion, but astrocytes also provide benefit for neuroprotection, by limiting lesion extension via anti-excitotoxicity effects and releasing neurotrophins. Similarly, during the late recovery phase after stroke, the glial scar may obstruct axonal regeneration and subsequently reduce the functional outcome; however, astrocytes also contribute to angiogenesis, neurogenesis, synaptogenesis, and axonal remodeling, and thereby promote neurological recovery. Thus, the pivotal involvement of astrocytes in normal brain function and responses to an ischemic lesion designates them as excellent therapeutic targets to improve functional outcome following stroke. In this review, we will focus on functions of astrocytes and astrocyte-mediated events during stroke and recovery. We will provide an overview of approaches on how to reduce the detrimental effects and amplify the beneficial effects of astrocytes on neuroprotection and on neurorestoration post stroke, which may lead to novel and clinically relevant therapies for stroke.
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Affiliation(s)
- Zhongwu Liu
- Department of Neurology, Henry Ford Hospital, Detroit, MI, USA.
| | - Michael Chopp
- Department of Neurology, Henry Ford Hospital, Detroit, MI, USA; Department of Physics, Oakland University, Rochester, MI, USA
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8
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The role of neuronal versus astrocyte-derived heparan sulfate proteoglycans in brain development and injury. Biochem Soc Trans 2015; 42:1263-9. [PMID: 25233401 DOI: 10.1042/bst20140166] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Astrocytes modulate many aspects of neuronal function, including synapse formation and the response to injury. Heparan sulfate proteoglycans (HSPGs) mediate some of the effects of astrocytes on synaptic function, and participate in the astrocyte-mediated brain injury response. HSPGs are a highly conserved class of proteoglycans, with variable heparan sulfate (HS) chains that play a major role in determining the function of these proteins, such as binding to growth factors and receptors. Expression of both the core proteins and their HS chains can vary depending on cellular origin, thus the functional impact of HSPGs may be determined by the cell type in which they are expressed. In the brain, HSPGs are expressed by both neurons and astrocytes; however, the specific contribution of neuronal HSPGs compared with astrocyte-derived HSPGs to development and the injury response is largely unknown. The present review examines the current evidence regarding the roles of HSPGs in the brain, describes the cellular origins of HSPGs, and interrogates the roles of HSPGs from astrocytes and neurons in synaptogenesis and injury. The importance of considering cell-type-specific expression of HSPGs when studying brain function is discussed.
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9
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Hansberg-Pastor V, González-Arenas A, Piña-Medina AG, Camacho-Arroyo I. Sex Hormones Regulate Cytoskeletal Proteins Involved in Brain Plasticity. Front Psychiatry 2015; 6:165. [PMID: 26635640 PMCID: PMC4653291 DOI: 10.3389/fpsyt.2015.00165] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 11/02/2015] [Indexed: 01/22/2023] Open
Abstract
In the brain of female mammals, including humans, a number of physiological and behavioral changes occur as a result of sex hormone exposure. Estradiol and progesterone regulate several brain functions, including learning and memory. Sex hormones contribute to shape the central nervous system by modulating the formation and turnover of the interconnections between neurons as well as controlling the function of glial cells. The dynamics of neuron and glial cells morphology depends on the cytoskeleton and its associated proteins. Cytoskeletal proteins are necessary to form neuronal dendrites and dendritic spines, as well as to regulate the diverse functions in astrocytes. The expression pattern of proteins, such as actin, microtubule-associated protein 2, Tau, and glial fibrillary acidic protein, changes in a tissue-specific manner in the brain, particularly when variations in sex hormone levels occur during the estrous or menstrual cycles or pregnancy. Here, we review the changes in structure and organization of neurons and glial cells that require the participation of cytoskeletal proteins whose expression and activity are regulated by estradiol and progesterone.
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Affiliation(s)
- Valeria Hansberg-Pastor
- Departamento de Biología, Facultad de Química, Universidad Nacional Autónoma de México , Mexico City , Mexico
| | - Aliesha González-Arenas
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México , Mexico City , Mexico
| | - Ana Gabriela Piña-Medina
- Unidad de Investigación en Reproducción Humana, Instituto Nacional de Perinatología-Facultad de Química, Universidad Nacional Autónoma de México , Mexico City , Mexico
| | - Ignacio Camacho-Arroyo
- Unidad de Investigación en Reproducción Humana, Instituto Nacional de Perinatología-Facultad de Química, Universidad Nacional Autónoma de México , Mexico City , Mexico
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10
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Goudriaan A, Camargo N, Carney KE, Oliet SHR, Smit AB, Verheijen MHG. Novel cell separation method for molecular analysis of neuron-astrocyte co-cultures. Front Cell Neurosci 2014; 8:12. [PMID: 24523672 PMCID: PMC3906515 DOI: 10.3389/fncel.2014.00012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 01/08/2014] [Indexed: 11/15/2022] Open
Abstract
Over the last decade, the importance of astrocyte-neuron communication in neuronal development and synaptic plasticity has become increasingly clear. Since neuron-astrocyte interactions represent highly dynamic and reciprocal processes, we hypothesized that many astrocyte genes may be regulated as a consequence of their interactions with maturing neurons. In order to identify such neuron-responsive astrocyte genes in vitro, we sought to establish an expedited technique for separation of neurons from co-cultured astrocytes. Our newly established method makes use of cold jet, which exploits different adhesion characteristics of subpopulations of cells (Jirsova etal., 1997), and is rapid, performed under ice-cold conditions and avoids protease-mediated isolation of astrocytes or time-consuming centrifugation, yielding intact astrocyte mRNA with approximately 90% of neuronal RNA removed. Using this purification method, we executed genome-wide profiling in which RNA derived from astrocyte-only cultures was compared with astrocyte RNA derived from differentiating neuron-astrocyte co-cultures. Data analysis determined that many astrocytic mRNAs and biological processes are regulated by neuronal interaction. Our results validate the cold jet as an efficient method to separate astrocytes from neurons in co-culture, and reveals that neurons induce robust gene-expression changes in co-cultured astrocytes.
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Affiliation(s)
- Andrea Goudriaan
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University Amsterdam Amsterdam, Netherlands
| | - Nutabi Camargo
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University Amsterdam Amsterdam, Netherlands
| | - Karen E Carney
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University Amsterdam Amsterdam, Netherlands ; INSERM U862, Neurocentre Magendie Bordeaux, France ; Université de Bordeaux Bordeaux, France
| | - Stéphane H R Oliet
- INSERM U862, Neurocentre Magendie Bordeaux, France ; Université de Bordeaux Bordeaux, France
| | - August B Smit
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University Amsterdam Amsterdam, Netherlands
| | - Mark H G Verheijen
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University Amsterdam Amsterdam, Netherlands
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11
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Cui H, Freeman C, Jacobson GA, Small DH. Proteoglycans in the central nervous system: role in development, neural repair, and Alzheimer's disease. IUBMB Life 2013; 65:108-20. [PMID: 23297096 DOI: 10.1002/iub.1118] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Accepted: 11/20/2012] [Indexed: 12/25/2022]
Abstract
Proteoglycans (PGs) are major components of the cell surface and extracellular matrix and play critical roles in development and maintenance of the central nervous system (CNS). PGs are a family of proteins, all of which contain a core protein to which glycosaminoglycan side chains are covalently attached. PGs possess diverse physiological roles, particularly in neural development, and are also implicated in the pathogenesis of neurodegenerative diseases such as Alzheimer's disease (AD). The main functions of PGs in the CNS are reviewed as are the roles of PGs in brain injury and in the development or treatment of AD.
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Affiliation(s)
- Hao Cui
- Menzies Research Institute Tasmania, University of Tasmania, Hobart, Tasmania, Australia
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12
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Changes in the content of GFAP in the rat brain during pregnancy and the beginning of lactation. Neurosci Lett 2010; 484:197-200. [DOI: 10.1016/j.neulet.2010.08.052] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Revised: 07/08/2010] [Accepted: 08/17/2010] [Indexed: 11/23/2022]
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13
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Su J, Gorse K, Ramirez F, Fox MA. Collagen XIX is expressed by interneurons and contributes to the formation of hippocampal synapses. J Comp Neurol 2010; 518:229-53. [PMID: 19937713 DOI: 10.1002/cne.22228] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Extracellular matrix (ECM) molecules contribute to the formation and maintenance of synapses in the mammalian nervous system. We previously discovered a family of nonfibrillar collagens that organize synaptic differentiation at the neuromuscular junction (NMJ). Although many NMJ-organizing cues contribute to central nervous system (CNS) synaptogenesis, whether similar roles for collagens exist at central synapses remained unclear. In the present study we discovered that col19a1, the gene encoding nonfibrillar collagen XIX, is expressed by subsets of hippocampal neurons. Colocalization with the interneuron-specific enzyme glutamate decarboxylase 67 (Gad67), but not other cell-type-specific markers, suggests that hippocampal expression of col19a1 is restricted to interneurons. However, not all hippocampal interneurons express col19a1 mRNA; subsets of neuropeptide Y (NPY)-, somatostatin (Som)-, and calbindin (Calb)-immunoreactive interneurons express col19a1, but those containing parvalbumin (Parv) or calretinin (Calr) do not. To assess whether collagen XIX is required for the normal formation of hippocampal synapses, we examined synaptic morphology and composition in targeted mouse mutants lacking collagen XIX. We show here that subsets of synaptotagmin 2 (Syt2)-containing hippocampal nerve terminals appear malformed in the absence of collagen XIX. The presence of Syt2 in inhibitory hippocampal synapses, the altered distribution of Gad67 in collagen XIX-deficient subiculum, and abnormal levels of gephyrin in collagen XIX-deficient hippocampal extracts all suggest inhibitory synapses are affected by the loss of collagen XIX. Together, these data not only reveal that collagen XIX is expressed by central neurons, but show for the first time that a nonfibrillar collagen is necessary for the formation of hippocampal synapses.
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Affiliation(s)
- Jianmin Su
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, Virginia 23298, USA
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14
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Koirala S, Corfas G. Identification of novel glial genes by single-cell transcriptional profiling of Bergmann glial cells from mouse cerebellum. PLoS One 2010; 5:e9198. [PMID: 20169146 PMCID: PMC2820553 DOI: 10.1371/journal.pone.0009198] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2009] [Accepted: 01/22/2010] [Indexed: 01/15/2023] Open
Abstract
Bergmann glial cells play critical roles in the structure and function of the cerebellum. During development, their radial processes serve as guides for migrating granule neurons and their terminal endfeet tile to form the glia limitans. As the cerebellum matures, Bergmann glia perform important roles in synaptic transmission and synapse maintenance, while continuing to serve as essential structural elements. Despite growing evidence of the diverse functions of Bergmann glia, the molecular mechanisms that mediate these functions have remained largely unknown. As a step toward identifying the molecular repertoire underlying Bergmann glial function, here we examine global gene expression in individual Bergmann glia from developing (P6) and mature (P30) mouse cerebellum. When we select for developmentally regulated genes, we find that transcription factors and ribosomal genes are particularly enriched at P6 relative to P30; whereas synapse associated molecules are enriched at P30 relative to P6. We also analyze genes expressed at high levels at both ages. In all these categories, we find genes that were not previously known to be expressed in glial cells, and discuss novel functions some of these genes may potentially play in Bergmann glia. We also show that Bergmann glia, even in the adult, express a large set of genes thought to be specific to stem cells, suggesting that Bergmann glia may retain neural precursor potential as has been proposed. Finally, we highlight several genes that in the cerebellum are expressed in Bergmann glia but not astrocytes, and may therefore serve as new, specific markers for Bergmann glia.
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Affiliation(s)
- Samir Koirala
- F.M. Kirby Neurobiology Center, Children's Hospital Boston, Boston, Massachusetts, United States of America
- Department of Neurology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Gabriel Corfas
- F.M. Kirby Neurobiology Center, Children's Hospital Boston, Boston, Massachusetts, United States of America
- Department of Neurology, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Otolaryngology, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
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15
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Role of glial cells in the formation and maintenance of synapses. ACTA ACUST UNITED AC 2009; 63:39-46. [PMID: 19931561 DOI: 10.1016/j.brainresrev.2009.11.002] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2009] [Revised: 11/06/2009] [Accepted: 11/11/2009] [Indexed: 11/23/2022]
Abstract
Synaptogenesis is a decisive process for the development of the brain, its plasticity during adulthood and its regeneration after injury and disease. Despite tremendous progress during the last decades, it remains unclear, whether neurons can form synapses autonomously. In this review, I will summarize recent evidence that this is probably not the case and that distinct phases of synapse development depend on help from glial cells. The results supporting this view come from studies on the central and peripheral nervous system and on different experimental models including cultured cells as well as living flies, worms and mice. Our understanding of synapse-glia interactions in the developing, adult and diseased brain is likely to advance more rapidly as new experimental approaches to identify, visualize and manipulate glial cells in vivo become available.
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16
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Pfrieger FW. Roles of glial cells in synapse development. Cell Mol Life Sci 2009; 66:2037-47. [PMID: 19308323 PMCID: PMC2705714 DOI: 10.1007/s00018-009-0005-7] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2008] [Revised: 01/20/2009] [Accepted: 02/10/2009] [Indexed: 11/29/2022]
Abstract
Brain function relies on communication among neurons via highly specialized contacts, the synapses, and synaptic dysfunction lies at the heart of age-, disease-, and injury-induced defects of the nervous system. For these reasons, the formation-and repair-of synaptic connections is a major focus of neuroscience research. In this review, I summarize recent evidence that synapse development is not a cell-autonomous process and that its distinct phases depend on assistance from the so-called glial cells. The results supporting this view concern synapses in the central nervous system as well as neuromuscular junctions and originate from experimental models ranging from cell cultures to living flies, worms, and mice. Peeking at the future, I will highlight recent technical advances that are likely to revolutionize our views on synapse-glia interactions in the developing, adult and diseased brain.
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Affiliation(s)
- Frank W Pfrieger
- Institute of Cellular and Integrative Neurosciences, CNRS UPR-3212, University of Strasbourg, 5, rue Louis Pasteur, 67084, Strasbourg, France.
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Transmembrane agrin regulates dendritic filopodia and synapse formation in mature hippocampal neuron cultures. Neuroscience 2009; 163:168-79. [PMID: 19524020 DOI: 10.1016/j.neuroscience.2009.06.012] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2008] [Revised: 05/31/2009] [Accepted: 06/06/2009] [Indexed: 12/21/2022]
Abstract
The transmembrane isoform of agrin (Tm-agrin) is the predominant form expressed in the brain but its putative roles in brain development are not well understood. Recent reports have implicated Tm-agrin in the formation and stabilization of filopodia on neurites of immature central and peripheral neurons in culture. In maturing central neurons, dendritic filopodia are believed to facilitate synapse formation. In the present study we have investigated the role of Tm-agrin in regulation of dendritic filopodia and synaptogenesis in maturing cultures of rat hippocampal neurons. We did this by infecting the neurons with an RNAi lentivirus to deplete endogenous agrin during the developmental period when filopodia density on the dendritic arbor was high, and synapse formation was rapid. We found that dendritic filopodia density was markedly reduced, as was synapse density along dendrites. Moreover, synapse formation was more sharply reduced on dendrites of infected neurons contacted by uninfected axons than on uninfected dendrites contacted by infected axons. The results are consistent with a physiological role for Tm-agrin in the maturation of hippocampal neurons involving positive regulation of dendritic filopodia and consequent promotion of synaptogenesis, but also suggest a role for axonal agrin in synaptogenesis.
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Arias C, Zepeda A, Hernández-Ortega K, Leal-Galicia P, Lojero C, Camacho-Arroyo I. Sex and estrous cycle-dependent differences in glial fibrillary acidic protein immunoreactivity in the adult rat hippocampus. Horm Behav 2009; 55:257-63. [PMID: 19056393 DOI: 10.1016/j.yhbeh.2008.10.016] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2008] [Revised: 10/28/2008] [Accepted: 10/29/2008] [Indexed: 11/21/2022]
Abstract
Sex differences in the morphology and function of the hippocampus have been reported in several species, but it is unknown whether a sexual dimorphism exists in glial fibrillary acidic protein (GFAP) expression in the rat hippocampus. We analyzed GFAP immunoreactivity in the hippocampus of intact adult male rats as well as in females during diestrus and proestrus phases of the estrous cycle. We found that in CA1, CA3, and dentate gyrus, GFAP immunoreactivity was higher in proestrus females as compared with males and diestrus females. In CA1, a similar GFAP immunoreactivity was found in males and in diestrus females, but in dentate gyrus, males presented the lowest GFAP content. Interestingly, differences in astrocyte morphology were also found. Rounded cells with numerous and short processes were mainly observed in the hippocampus during proestrus whereas cells with stellate shape with few and long processes were present in the hippocampus of males and diestrus females. The marked sex and estrous cycle-dependent differences in GFAP immunoreactivity density and in astrocyte number and morphology found in the rat hippocampus, suggest the involvement of sex steroid hormones in the sexually dimorphic functions of the hippocampus, and in the change in its activity during the estrous cycle.
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Affiliation(s)
- Clorinda Arias
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico
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Waters EM, Torres-Reveron A, McEwen BS, Milner TA. Ultrastructural localization of extranuclear progestin receptors in the rat hippocampal formation. J Comp Neurol 2008; 511:34-46. [PMID: 18720413 DOI: 10.1002/cne.21826] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Progesterone's effects on hippocampus-dependent behavior and synaptic connectivity maybe mediated through the progestin receptor (PR). Although estrogen induces PR mRNA and cytosolic PR in the hippocampus, nuclear PR immunoreactivity is undetectable by light microscopy, suggesting that PR is present at extranuclear sites. To determine whether this is the case, we used immunoelectron microscopy to examine PR distribution in the hippocampal formation of proestrus rats. Ultrastructural analysis revealed that PR labeling is present in extranuclear profiles throughout the CA1 and CA3 regions and dentate gyrus, and, in contrast to light microscopic findings, in nuclei of a few pyramidal and subgranular zone cells. Most neuronal PR labeling is extranuclear and is divided between pre- and postsynaptic compartments; approximately 30% of labeled profiles were axon terminals and 30% were dendrites and dendritic spines. In most laminae, except in CA3 stratum lucidum, about 15% of PR-immunoreactive profiles were unmyelinated axons. In stratum lucidum, where the mossy fiber axons course, more than 50% of PR-labeled profiles were axonal. The remaining 25% of PR-labeled profiles were glia, some resembling astrocytes. PR labeling is strongly dependent on estrogen priming, insofar as few PR-labeled profiles were detected in ovariectomized, oil-replaced females. Synapses formed by PR-labeled terminals were predominantly asymmetric, consistent with a role for progesterone in directly regulating excitatory transmission. These findings suggest that some of progesterone's actions in the hippocampal formation may be mediated by direct and rapid actions on extranuclear PRs and that PRs are well positioned to regulate progesterone-induced changes at synapses.
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Affiliation(s)
- Elizabeth M Waters
- Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology, The Rockefeller University, New York, New York 10065, USA.
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Falo MC, Reeves TM, Phillips LL. Agrin expression during synaptogenesis induced by traumatic brain injury. J Neurotrauma 2008; 25:769-83. [PMID: 18627255 DOI: 10.1089/neu.2008.0511] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Interaction between extracellular matrix proteins and regulatory proteinases can mediate synaptic integrity. Previously, we documented that matrix metalloproteinase 3 (MMP-3) expression and activity increase following traumatic brain injury (TBI). We now report protein and mRNA analysis of agrin, a MMP-3 substrate, over the time course of trauma-induced synaptogenesis. Agrin expression during the successful synaptic reorganization of unilateral entorhinal cortical lesion (UEC) was compared with expression when normal synaptogenesis fails (combined fluid percussion TBI and bilateral entorhinal lesion [BEC]). We observed that agrin protein was increased in both models at 2 and 7 days postinjury, and immuohistochemical (IHC) co-localization suggested reactive astrocytes contribute to that increase. Agrin formed defined boundaries for sprouting axons along deafferented dendrites in the UEC, but failed to do so after combined insult. Similarly, Western blot analysis revealed greater increase in UEC agrin protein relative to the combined TBI+BEC model. Both models showed increased agrin transcription at 7 days postinjury and mRNA normalization by 15 days. Attenuation of synaptic pathology with the NMDA antagonist MK-801 reduced 7-day UEC agrin transcript to a level not different from unlesioned controls. By contrast, MK-801 in the combined insult failed to significantly change 7-day agrin transcript, mRNA levels remaining elevated over uninjured sham cases. Together, these results suggest that agrin plays an important role in the sprouting phase of reactive synaptogenesis, and that both its expression and distribution are correlated with extent of successful recovery after TBI. Further, when pathogenic conditions which induce synaptic plasticity are reduced, increase in agrin mRNA is attenuated.
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Affiliation(s)
- M Cristina Falo
- Department of Anatomy and Neurobiology, School of Medicine, Virginia Commonwealth University Medical Center, Richmond, Virginia 23298, USA
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Williams S, Ryan C, Jacobson C. Agrin and neuregulin, expanding roles and implications for therapeutics. Biotechnol Adv 2008; 26:187-201. [DOI: 10.1016/j.biotechadv.2007.11.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2007] [Revised: 11/21/2007] [Accepted: 11/21/2007] [Indexed: 01/15/2023]
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Morita K. High salt culture conditions inhibit serum- and NGF- but not PMA-induced Egr-1 gene transcription in rat C6 glioma cells. J Mol Neurosci 2008; 33:216-23. [PMID: 17917080 DOI: 10.1007/s12031-007-9000-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2007] [Revised: 11/30/1999] [Accepted: 08/10/2007] [Indexed: 12/24/2022]
Abstract
Recent studies have suggested that glial cells may play a physiologically important role in the retention and restoration of neuronal cell integrity, proposing the possibility that the proliferation and/or differentiation of glial cells may be related to pathological changes in neural functions in neurodegenerative diseases, and hence, it seems interesting to investigate the expression of genes related to the proliferation and differentiation of glial cells. Following this basic concept, we have previously examined the influence of culture conditions on egr-1 gene expression in rat C6 glioma cells and have shown that brief exposure of these cells to high salt culture medium can induce the down-regulation of egr-1 gene expression. In contrast, the long-term culture of these cells in high salt medium has been shown to primarily reduce their proliferation and secondarily elevate egr-1 gene transcription as a consequence of arresting the cell-cycle progression. Therefore, the effect of high salt culture medium on egr-1 gene expression seems practically unconfirmed, and remains to be further investigated. Then, the effects of various egr-1 gene inducers, such as serum, NGF and phorbol ester PMA, on Egr-1 mRNA levels in the glioma cells were examined under the high salt culture conditions. The brief exposure to high salt culture medium inhibited the elevation of Egr-1 mRNA levels induced by serum replenishment and NGF, but not induced by PMA. These results suggest that the suppression of serum action on egr-1 gene transcription may be the primary and essential event leading to the down-regulation of egr-1 gene expression under the high salt culture conditions.
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Affiliation(s)
- Kyoji Morita
- Department of Pharmacology, Tokushima University School of Medicine, 3-18-15 Kuramoto, Tokushima, Japan.
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Progesterone Pretreatment Enhances Serotonin-Stimulated BDNF Gene Expression in Rat C6 Glioma Cells Through Production of 5α-Reduced Neurosteroids. J Mol Neurosci 2008; 34:193-200. [DOI: 10.1007/s12031-007-9034-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2007] [Accepted: 12/13/2007] [Indexed: 10/22/2022]
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Costain WJ, Rasquinha I, Sandhu JK, Rippstein P, Zurakowski B, Slinn J, MacManus JP, Stanimirovic DB. Cerebral ischemia causes dysregulation of synaptic adhesion in mouse synaptosomes. J Cereb Blood Flow Metab 2008; 28:99-110. [PMID: 17519975 DOI: 10.1038/sj.jcbfm.9600510] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Synaptic pathology is observed during hypoxic events in the central nervous system in the form of altered dendrite structure and conductance changes. These alterations are rapidly reversible, on the return of normoxia, but are thought to initiate subsequent neuronal cell death. To characterize the effects of hypoxia on regulators of synaptic stability, we examined the temporal expression of cell adhesion molecules (CAMs) in synaptosomes after transient middle cerebral artery occlusion (MCAO) in mice. We focused on events preceding the onset of ischemic neuronal cell death (<48 h). Synaptosome preparations were enriched in synaptically localized proteins and were free of endoplasmic reticulum and nuclear contamination. Electron microscopy showed that the synaptosome preparation was enriched in spheres (approximately 650 nm in diameter) containing secretory vesicles and postsynaptic densities. Forebrain mRNA levels of synaptically located CAMs was unaffected at 3 h after MCAO. This is contrasted by the observation of consistent downregulation of synaptic CAMs at 20 h after MCAO. Examination of synaptosomal CAM protein content indicated that certain adhesion molecules were decreased as early as 3 h after MCAO. For comparison, synaptosomal Agrn protein levels were unaffected by cerebral ischemia. Furthermore, a marked increase in the levels of p-Ctnnb1 in ischemic synaptosomes was observed. p-Ctnnb1 was detected in hippocampal fiber tracts and in cornu ammonis 1 neuronal nuclei. These results indicate that ischemia induces a dysregulation of a subset of synaptic proteins that are important regulators of synaptic plasticity before the onset of ischemic neuronal cell death.
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Affiliation(s)
- Willard J Costain
- Glycosyltransferase and Neuroglycomics, Institute for Biological Sciences, National Research Council, Ottawa, Ontario, Canada.
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Bergstrom RA, Sinjoanu RC, Ferreira A. Agrin induced morphological and structural changes in growth cones of cultured hippocampal neurons. Neuroscience 2007; 149:527-36. [PMID: 17870250 PMCID: PMC2675609 DOI: 10.1016/j.neuroscience.2007.08.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2007] [Revised: 07/31/2007] [Accepted: 09/06/2007] [Indexed: 12/28/2022]
Abstract
The role of agrin in synaptogenesis has been extensively studied. On the other hand, little is known about the function of this extracellular matrix protein during developmental processes that precede the formation of synapses. Recently, agrin was shown to regulate the rate of neurite elongation and the behavior of growth cones in hippocampal and spinal neurons, respectively. However, the molecular mechanisms underlying these effects have not been completely elucidated. In the present study, we analyzed the morphological and molecular changes induced by agrin in growth cones of hippocampal neurons that developed in culture. Morphometric analysis showed a significant enlargement of growth cones of hippocampal neurons cultured in the presence of agrin. These agrin-induced growth cone changes were accompanied by the formation of loops of microtubules highly enriched in acetylated tubulin and an increase in the content of the microtubule-associated protein (MAP)1B. Together, these data provide further insights into the potential molecular mechanisms underlying the effects of agrin on neurite outgrowth in rat central neurons.
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Affiliation(s)
| | | | - Adriana Ferreira
- Correspondence should be addressed to: Adriana Ferreira, M.D., Ph.D. Department of Cell and Molecular Biology Feinberg Medical School Northwestern University Searle Building Room 5-474 320 East Superior Street Chicago, Illinois 60611 Phone (312) 503 0597; Fax (312) 503 7345 E-mail:
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