1
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Radu R, Petrescu GED, Gorgan RM, Brehar FM. GFAPδ: A Promising Biomarker and Therapeutic Target in Glioblastoma. Front Oncol 2022; 12:859247. [PMID: 35372061 PMCID: PMC8971704 DOI: 10.3389/fonc.2022.859247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 02/24/2022] [Indexed: 12/02/2022] Open
Abstract
GFAPδ, the delta isoform of the glial fibrillary acidic protein, is mainly expressed in the subventricular zone of the brain, together with other neural stem cell markers like nestin. The authors of this paper were among the first that described in detail the expression of GFAPδ and its correlation with malignancy and invasiveness in cerebral astrocytoma. Later, several papers confirmed these findings, showing that the alternative splice variant GFAPδ is overexpressed in glioblastoma (CNS WHO grade 4) compared with lower grade gliomas. Other studies suggested that a high GFAPδ/α ratio is associated with a more malignant and invasive behavior of glioma cells. Moreover, the changing of GFAPδ/α ratio affects the expression of high-malignant genes. It is now suggested that discriminating between predominant GFAP isoforms, GFAPδ or GFAPα, is useful for assessing the malignancy state of astrocytoma, and may even contribute to the classification of gliomas. Therefore, the purpose of this paper is to review the literature with emphasize on the role of GFAPδ as a potential biomarker, and as a possible therapeutic target in glioblastoma.
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Affiliation(s)
- Roxana Radu
- Department of Neurosurgery, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
- Department of Neurosurgery, Bagdasar-Arseni Clinical Emergency Hospital, Bucharest, Romania
| | - George E. D. Petrescu
- Department of Neurosurgery, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
- Department of Neurosurgery, Bagdasar-Arseni Clinical Emergency Hospital, Bucharest, Romania
- *Correspondence: George E. D. Petrescu,
| | - Radu M. Gorgan
- Department of Neurosurgery, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
- Department of Neurosurgery, Bagdasar-Arseni Clinical Emergency Hospital, Bucharest, Romania
| | - Felix M. Brehar
- Department of Neurosurgery, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
- Department of Neurosurgery, Bagdasar-Arseni Clinical Emergency Hospital, Bucharest, Romania
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2
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Uceda-Castro R, van Asperen JV, Vennin C, Sluijs JA, van Bodegraven EJ, Margarido AS, Robe PAJ, van Rheenen J, Hol EM. GFAP splice variants fine-tune glioma cell invasion and tumour dynamics by modulating migration persistence. Sci Rep 2022; 12:424. [PMID: 35013418 PMCID: PMC8748899 DOI: 10.1038/s41598-021-04127-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 12/16/2021] [Indexed: 12/26/2022] Open
Abstract
Glioma is the most common form of malignant primary brain tumours in adults. Their highly invasive nature makes the disease incurable to date, emphasizing the importance of better understanding the mechanisms driving glioma invasion. Glial fibrillary acidic protein (GFAP) is an intermediate filament protein that is characteristic for astrocyte- and neural stem cell-derived gliomas. Glioma malignancy is associated with changes in GFAP alternative splicing, as the canonical isoform GFAPα is downregulated in higher-grade tumours, leading to increased dominance of the GFAPδ isoform in the network. In this study, we used intravital imaging and an ex vivo brain slice invasion model. We show that the GFAPδ and GFAPα isoforms differentially regulate the tumour dynamics of glioma cells. Depletion of either isoform increases the migratory capacity of glioma cells. Remarkably, GFAPδ-depleted cells migrate randomly through the brain tissue, whereas GFAPα-depleted cells show a directionally persistent invasion into the brain parenchyma. This study shows that distinct compositions of the GFAPnetwork lead to specific migratory dynamics and behaviours of gliomas.
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Affiliation(s)
- Rebeca Uceda-Castro
- Division of Molecular Pathology, Oncode Institute, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Jessy V van Asperen
- Department of Translational Neuroscience, University Medical Center Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Claire Vennin
- Division of Molecular Pathology, Oncode Institute, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Jacqueline A Sluijs
- Department of Translational Neuroscience, University Medical Center Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Emma J van Bodegraven
- Department of Translational Neuroscience, University Medical Center Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Andreia S Margarido
- Division of Molecular Pathology, Oncode Institute, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Pierre A J Robe
- Department of Neurology and Neurosurgery, University Medical Center Utrecht Brain Center, University Utrecht, Utrecht, The Netherlands
| | - Jacco van Rheenen
- Division of Molecular Pathology, Oncode Institute, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
| | - Elly M Hol
- Department of Translational Neuroscience, University Medical Center Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands.
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3
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van Asperen JV, Robe PA, Hol EM. GFAP Alternative Splicing and the Relevance for Disease – A Focus on Diffuse Gliomas. ASN Neuro 2022; 14:17590914221102065. [PMID: 35673702 PMCID: PMC9185002 DOI: 10.1177/17590914221102065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Glial fibrillary acidic protein (GFAP) is an intermediate filament protein that is
characteristic for astrocytes and neural stem cells, and their malignant analogues in
glioma. Since the discovery of the protein 50 years ago, multiple alternative splice
variants of the GFAP gene have been discovered, leading to different GFAP isoforms. In
this review, we will describe GFAP isoform expression from gene to protein to network,
taking the canonical isoforms GFAPα and the main alternative variant GFAPδ as the starting
point. We will discuss the relevance of studying GFAP and its isoforms in disease, with a
specific focus on diffuse gliomas.
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Affiliation(s)
- Jessy V. van Asperen
- Department of Translational Neuroscience, University Medical Center Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Pierre A.J.T. Robe
- Department of Neurology and Neurosurgery, University Medical Center Utrecht Brain Center, University Utrecht, Utrecht, The Netherlands
| | - Elly M. Hol
- Department of Translational Neuroscience, University Medical Center Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
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4
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Leite JP, Peixoto-Santos JE. Glia and extracellular matrix molecules: What are their importance for the electrographic and MRI changes in the epileptogenic zone? Epilepsy Behav 2021; 121:106542. [PMID: 31884121 DOI: 10.1016/j.yebeh.2019.106542] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 09/02/2019] [Accepted: 09/04/2019] [Indexed: 12/22/2022]
Abstract
Glial cells and extracellular matrix (ECM) molecules are crucial for the maintenance of brain homeostasis. Especially because of their actions regarding neurotransmitter and ionic control, and synaptic function, these cells can potentially contribute to the hyperexcitability seen in the epileptogenic, while ECM changes are linked to synaptic reorganization. The present review will explore glial and ECM homeostatic roles and their potential contribution to tissue plasticity. Finally, we will address how glial, and ECM changes in the epileptogenic zone can be seen in magnetic resonance imaging (MRI), pointing out their importance as markers for the extension of the epileptogenic area. This article is part of the Special Issue "NEWroscience 2018".
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Affiliation(s)
- Joao Pereira Leite
- Neurosciences and Behavioral Sciences, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, Brazil.
| | - Jose Eduardo Peixoto-Santos
- Neurosciences and Behavioral Sciences, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, Brazil; Department of Neurology and Neurosurgery, Paulista School of Medicine, UNIFESP, Sao Paulo, Brazil
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5
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Zwirner J, Lier J, Franke H, Hammer N, Matschke J, Trautz F, Tse R, Ondruschka B. GFAP positivity in neurons following traumatic brain injuries. Int J Legal Med 2021; 135:2323-2333. [PMID: 34114049 PMCID: PMC8523453 DOI: 10.1007/s00414-021-02568-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Accepted: 03/10/2021] [Indexed: 11/29/2022]
Abstract
Glial fibrillary acidic protein (GFAP) is a well-established astrocytic biomarker for the diagnosis, monitoring and outcome prediction of traumatic brain injury (TBI). Few studies stated an accumulation of neuronal GFAP that was observed in various brain pathologies, including traumatic brain injuries. As the neuronal immunopositivity for GFAP in Alzheimer patients was shown to cross-react with non-GFAP epitopes, the neuronal immunopositivity for GFAP in TBI patients should be challenged. In this study, cerebral and cerebellar tissues of 52 TBI fatalities and 17 controls were screened for immunopositivity for GFAP in neurons by means of immunohistochemistry and immunofluorescence. The results revealed that neuronal immunopositivity for GFAP is most likely a staining artefact as negative controls also revealed neuronal GFAP staining. However, the phenomenon was twice as frequent for TBI fatalities compared to non-TBI control cases (12 vs. 6%). Neuronal GFAP staining was observed in the pericontusional zone and the ipsilateral hippocampus, but was absent in the contralateral cortex of TBI cases. Immunopositivity for GFAP was significantly correlated with the survival time (r = 0.306, P = 0.015), but no correlations were found with age at death, sex nor the post-mortem interval in TBI fatalities. This study provides evidence that the TBI-associated neuronal immunopositivity for GFAP is indeed a staining artefact. However, an absence post-traumatic neuronal GFAP cannot readily be assumed. Regardless of the particular mechanism, this study revealed that the artefact/potential neuronal immunopositivity for GFAP is a global, rather than a regional brain phenomenon and might be useful for minimum TBI survival time determinations, if certain exclusion criteria are strictly respected.
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Affiliation(s)
- Johann Zwirner
- Department of Anatomy, University of Otago, Dunedin, New Zealand. .,Institute of Legal Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany. .,Institute of Legal Medicine, University of Leipzig, Leipzig, Germany.
| | - Julia Lier
- Institute of Anatomy, University of Leipzig, Leipzig, Germany
| | - Heike Franke
- Rudolf Boehm Institute of Pharmacology and Toxicology, University of Leipzig, Leipzig, Germany
| | - Niels Hammer
- Institute of Macroscopic and Clinical Anatomy, University of Graz, Graz, Austria.,Department of Trauma, Orthopedic and Plastic Surgery, University Hospital of Leipzig, Leipzig, Germany.,Fraunhofer Institute for Machine Tools and Forming Technology, Dresden, Germany
| | - Jakob Matschke
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Florian Trautz
- Institute of Legal Medicine, University of Leipzig, Leipzig, Germany
| | - Rexon Tse
- Department of Forensic Pathology, LabPLUS, Auckland City Hospital, Auckland, New Zealand
| | - Benjamin Ondruschka
- Institute of Legal Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
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6
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Bozic I, Savic D, Lavrnja I. Astrocyte phenotypes: Emphasis on potential markers in neuroinflammation. Histol Histopathol 2020; 36:267-290. [PMID: 33226087 DOI: 10.14670/hh-18-284] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Astrocytes, the most abundant glial cells in the central nervous system (CNS), have numerous integral roles in all CNS functions. They are essential for synaptic transmission and support neurons by providing metabolic substrates, secreting growth factors and regulating extracellular concentrations of ions and neurotransmitters. Astrocytes respond to CNS insults through reactive astrogliosis, in which they go through many functional and molecular changes. In neuroinflammatory conditions reactive astrocytes exert both beneficial and detrimental functions, depending on the context and heterogeneity of astrocytic populations. In this review we profile astrocytic diversity in the context of neuroinflammation; with a specific focus on multiple sclerosis (MS) and its best-described animal model experimental autoimmune encephalomyelitis (EAE). We characterize two main subtypes, protoplasmic and fibrous astrocytes and describe the role of intermediate filaments in the physiology and pathology of these cells. Additionally, we outline a variety of markers that are emerging as important in investigating astrocytic biology in both physiological conditions and neuroinflammation.
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Affiliation(s)
- Iva Bozic
- Institute for Biological Research "Sinisa Stankovic", National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Danijela Savic
- Institute for Biological Research "Sinisa Stankovic", National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Irena Lavrnja
- Institute for Biological Research "Sinisa Stankovic", National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia.
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7
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van Bodegraven EJ, van Asperen JV, Robe PAJ, Hol EM. Importance of GFAP isoform-specific analyses in astrocytoma. Glia 2019; 67:1417-1433. [PMID: 30667110 PMCID: PMC6617972 DOI: 10.1002/glia.23594] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 12/28/2018] [Accepted: 01/03/2019] [Indexed: 12/12/2022]
Abstract
Gliomas are a heterogenous group of malignant primary brain tumors that arise from glia cells or their progenitors and rely on accurate diagnosis for prognosis and treatment strategies. Although recent developments in the molecular biology of glioma have improved diagnosis, classical histological methods and biomarkers are still being used. The glial fibrillary acidic protein (GFAP) is a classical marker of astrocytoma, both in clinical and experimental settings. GFAP is used to determine glial differentiation, which is associated with a less malignant tumor. However, since GFAP is not only expressed by mature astrocytes but also by radial glia during development and neural stem cells in the adult brain, we hypothesized that GFAP expression in astrocytoma might not be a direct indication of glial differentiation and a less malignant phenotype. Therefore, we here review all existing literature from 1972 up to 2018 on GFAP expression in astrocytoma patient material to revisit GFAP as a marker of lower grade, more differentiated astrocytoma. We conclude that GFAP is heterogeneously expressed in astrocytoma, which most likely masks a consistent correlation of GFAP expression to astrocytoma malignancy grade. The GFAP positive cell population contains cells with differences in morphology, function, and differentiation state showing that GFAP is not merely a marker of less malignant and more differentiated astrocytoma. We suggest that discriminating between the GFAP isoforms GFAPδ and GFAPα will improve the accuracy of assessing the differentiation state of astrocytoma in clinical and experimental settings and will benefit glioma classification.
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Affiliation(s)
- Emma J van Bodegraven
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| | - Jessy V van Asperen
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| | - Pierre A J Robe
- Department of Neurology and Neurosurgery, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| | - Elly M Hol
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands.,Netherlands Institute for Neuroscience, An Institute of the Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105, BA, Amsterdam, The Netherlands
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8
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Moeton M, Stassen OMJA, Sluijs JA, van der Meer VWN, Kluivers LJ, van Hoorn H, Schmidt T, Reits EAJ, van Strien ME, Hol EM. GFAP isoforms control intermediate filament network dynamics, cell morphology, and focal adhesions. Cell Mol Life Sci 2016; 73:4101-20. [PMID: 27141937 PMCID: PMC5043008 DOI: 10.1007/s00018-016-2239-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 04/12/2016] [Accepted: 04/21/2016] [Indexed: 11/01/2022]
Abstract
Glial fibrillary acidic protein (GFAP) is the characteristic intermediate filament (IF) protein in astrocytes. Expression of its main isoforms, GFAPα and GFAPδ, varies in astrocytes and astrocytoma implying a potential regulatory role in astrocyte physiology and pathology. An IF-network is a dynamic structure and has been functionally linked to cell motility, proliferation, and morphology. There is a constant exchange of IF-proteins with the network. To study differences in the dynamic properties of GFAPα and GFAPδ, we performed fluorescence recovery after photobleaching experiments on astrocytoma cells with fluorescently tagged GFAPs. Here, we show for the first time that the exchange of GFP-GFAPδ was significantly slower than the exchange of GFP-GFAPα with the IF-network. Furthermore, a collapsed IF-network, induced by GFAPδ expression, led to a further decrease in fluorescence recovery of both GFP-GFAPα and GFP-GFAPδ. This altered IF-network also changed cell morphology and the focal adhesion size, but did not alter cell migration or proliferation. Our study provides further insight into the modulation of the dynamic properties and functional consequences of the IF-network composition.
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Affiliation(s)
- Martina Moeton
- Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
| | - Oscar M J A Stassen
- Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
- Soft Tissue Biomechanics & Engineering, Department of biomedical engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Jacqueline A Sluijs
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG, Utrecht, The Netherlands
| | - Vincent W N van der Meer
- Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
| | - Liselot J Kluivers
- Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
| | - Hedde van Hoorn
- Physics of Life Processes, Leiden Institute of Physics, Leiden, The Netherlands
| | - Thomas Schmidt
- Physics of Life Processes, Leiden Institute of Physics, Leiden, The Netherlands
| | - Eric A J Reits
- Cell Biology and Histology, AMC Medical Center, Amsterdam, The Netherlands
| | - Miriam E van Strien
- Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG, Utrecht, The Netherlands
| | - Elly M Hol
- Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands.
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG, Utrecht, The Netherlands.
- Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, The Netherlands.
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9
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Glial fibrillary acidic protein (GFAP) and the astrocyte intermediate filament system in diseases of the central nervous system. Curr Opin Cell Biol 2015; 32:121-30. [PMID: 25726916 DOI: 10.1016/j.ceb.2015.02.004] [Citation(s) in RCA: 524] [Impact Index Per Article: 58.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Revised: 02/04/2015] [Accepted: 02/09/2015] [Indexed: 01/14/2023]
Abstract
Glial fibrillary acidic protein (GFAP) is the hallmark intermediate filament (IF; also known as nanofilament) protein in astrocytes, a main type of glial cells in the central nervous system (CNS). Astrocytes have a range of control and homeostatic functions in health and disease. Astrocytes assume a reactive phenotype in acute CNS trauma, ischemia, and in neurodegenerative diseases. This coincides with an upregulation and rearrangement of the IFs, which form a highly complex system composed of GFAP (10 isoforms), vimentin, synemin, and nestin. We begin to unravel the function of the IF system of astrocytes and in this review we discuss its role as an important crisis-command center coordinating cell responses in situations connected to cellular stress, which is a central component of many neurological diseases.
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10
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Astrocitos en las enfermedades neurodegenerativas (I): función y caracterización molecular. Neurologia 2015; 30:119-29. [DOI: 10.1016/j.nrl.2012.12.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Accepted: 12/15/2012] [Indexed: 12/23/2022] Open
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11
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Guillamón-Vivancos T, Gómez-Pinedo U, Matías-Guiu J. Astrocytes in neurodegenerative diseases (I): function and molecular description. NEUROLOGÍA (ENGLISH EDITION) 2015. [DOI: 10.1016/j.nrleng.2014.12.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
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12
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Brehar FM, Arsene D, Brinduse LA, Gorgan MR. Immunohistochemical analysis of GFAP-δ and nestin in cerebral astrocytomas. Brain Tumor Pathol 2014; 32:90-8. [DOI: 10.1007/s10014-014-0199-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2014] [Accepted: 08/10/2014] [Indexed: 11/24/2022]
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13
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Kanski R, Sneeboer MAM, van Bodegraven EJ, Sluijs JA, Kropff W, Vermunt MW, Creyghton MP, De Filippis L, Vescovi A, Aronica E, van Tijn P, van Strien ME, Hol EM. Histone acetylation in astrocytes suppresses GFAP and stimulates a re-organization of the intermediate filament network. J Cell Sci 2014; 127:4368-80. [DOI: 10.1242/jcs.145912] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Glial Fibrillary Acidic Protein (GFAP) is the main intermediate filament in astrocytes and is regulated by epigenetic mechanisms during development. We demonstrate that histone acetylation controls GFAP expression also in mature astrocytes. Inhibition of histone deacetylases (HDACs) with Trichostatin-A or Sodium-butyrate reduced GFAP expression in primary human astrocytes and astrocytoma cells. Since splicing occurs co-transcriptional, we investigated whether histone acetylation changes the ratio between the canonical isoform GFAPα and the alternative GFAPδ splice-variant. We observed that decreased transcription of GFAP enhanced alternative isoform expression, as HDAC inhibition increased the GFAPδ/α ratio favouring GFAPδ. Expression of GFAPδ was dependent on the presence and binding of the splicing factors of the SR protein family. Inhibition of HDAC activity also resulted in aggregation of the GFAP network, reminiscent to our earlier findings of a GFAPδ-induced network collapse. Together, our data demonstrate that HDAC inhibition results in changes in transcription, splicing, and organization of GFAP. These data imply that a tight regulation of histone acetylation in astrocytes is essential, since dysregulation of gene expression causes aggregation of GFAP, a hallmark of human diseases like Alexander's disease.
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14
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Thomsen R, Daugaard TF, Holm IE, Nielsen AL. Alternative mRNA splicing from the glial fibrillary acidic protein (GFAP) gene generates isoforms with distinct subcellular mRNA localization patterns in astrocytes. PLoS One 2013; 8:e72110. [PMID: 23991052 PMCID: PMC3753360 DOI: 10.1371/journal.pone.0072110] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 07/06/2013] [Indexed: 11/20/2022] Open
Abstract
The intermediate filament network of astrocytes includes Glial fibrillary acidic protein (Gfap) as a major component. Gfap mRNA is alternatively spliced resulting in generation of different protein isoforms where Gfapα is the most predominant isoform. The Gfapδ isoform is expressed in proliferating neurogenic astrocytes of the developing human brain and in the adult human and mouse brain. Here we provide a characterization of mouse Gfapδ mRNA and Gfapδ protein. RT-qPCR analysis showed that Gfapδ mRNA and Gfapα mRNA expression is coordinately increased in the post-natal period. Immunohistochemical staining of developing mouse brain samples showed that Gfapδ is expressed in the sub-ventricular zones in accordance with the described localization in the developing and adult human brain. Immunofluorescence analysis verified incorporation of Gfapδ into the Gfap intermediate filament network and overlap in Gfapδ and Gfapα subcellular localization. Subcellular mRNA localization studies identified different localization patterns of Gfapδ and Gfapα mRNA in mouse primary astrocytes. A larger fraction of Gfapα mRNA showed mRNA localization to astrocyte protrusions compared to Gfapδ mRNA. The differential mRNA localization patterns were dependent on the different 3′-exon sequences included in Gfapδ and Gfapα mRNA. The presented results show that alternative Gfap mRNA splicing results in isoform-specific mRNA localization patterns with resulting different local mRNA concentration ratios which have potential to participate in subcellular region-specific intermediate filament dynamics during brain development, maintenance and in disease.
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Affiliation(s)
- Rune Thomsen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
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15
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Kamphuis W, Mamber C, Moeton M, Kooijman L, Sluijs JA, Jansen AHP, Verveer M, de Groot LR, Smith VD, Rangarajan S, Rodríguez JJ, Orre M, Hol EM. GFAP isoforms in adult mouse brain with a focus on neurogenic astrocytes and reactive astrogliosis in mouse models of Alzheimer disease. PLoS One 2012. [PMID: 22912745 DOI: 10.1371/journal.pone.0042823]] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Glial fibrillary acidic protein (GFAP) is the main astrocytic intermediate filament (IF). GFAP splice isoforms show differential expression patterns in the human brain. GFAPδ is preferentially expressed by neurogenic astrocytes in the subventricular zone (SVZ), whereas GFAP(+1) is found in a subset of astrocytes throughout the brain. In addition, the expression of these isoforms in human brain material of epilepsy, Alzheimer and glioma patients has been reported. Here, for the first time, we present a comprehensive study of GFAP isoform expression in both wild-type and Alzheimer Disease (AD) mouse models. In cortex, cerebellum, and striatum of wild-type mice, transcripts for Gfap-α, Gfap-β, Gfap-γ, Gfap-δ, Gfap-κ, and a newly identified isoform Gfap-ζ, were detected. Their relative expression levels were similar in all regions studied. GFAPα showed a widespread expression whilst GFAPδ distribution was prominent in the SVZ, rostral migratory stream (RMS), neurogenic astrocytes of the subgranular zone (SGZ), and subpial astrocytes. In contrast to the human SVZ, we could not establish an unambiguous GFAPδ localization in proliferating cells of the mouse SVZ. In APPswePS1dE9 and 3xTgAD mice, plaque-associated reactive astrocytes had increased transcript levels of all detectable GFAP isoforms and low levels of a new GFAP isoform, Gfap-ΔEx7. Reactive astrocytes in AD mice showed enhanced GFAPα and GFAPδ immunolabeling, less frequently increased vimentin and nestin, but no GFAPκ or GFAP(+1) staining. In conclusion, GFAPδ protein is present in SVZ, RMS, and neurogenic astrocytes of the SGZ, but also outside neurogenic niches. Furthermore, differential GFAP isoform expression is not linked with aging or reactive gliosis. This evidence points to the conclusion that differential regulation of GFAP isoforms is not involved in the reorganization of the IF network in reactive gliosis or in neurogenesis in the mouse brain.
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Affiliation(s)
- Willem Kamphuis
- Netherlands Institute for Neuroscience - an Institute of the Royal Netherlands Academy of Arts and Sciences, Department of Astrocyte Biology & Neurodegeneration, Amsterdam, The Netherlands.
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Rai A, Maurya SK, Sharma R, Ali S. Down-regulated GFAPα: a major player in heavy metal induced astrocyte damage. Toxicol Mech Methods 2012; 23:99-107. [DOI: 10.3109/15376516.2012.721809] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Kamphuis W, Mamber C, Moeton M, Kooijman L, Sluijs JA, Jansen AHP, Verveer M, de Groot LR, Smith VD, Rangarajan S, Rodríguez JJ, Orre M, Hol EM. GFAP isoforms in adult mouse brain with a focus on neurogenic astrocytes and reactive astrogliosis in mouse models of Alzheimer disease. PLoS One 2012; 7:e42823. [PMID: 22912745 PMCID: PMC3418292 DOI: 10.1371/journal.pone.0042823] [Citation(s) in RCA: 215] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Accepted: 07/11/2012] [Indexed: 11/19/2022] Open
Abstract
Glial fibrillary acidic protein (GFAP) is the main astrocytic intermediate filament (IF). GFAP splice isoforms show differential expression patterns in the human brain. GFAPδ is preferentially expressed by neurogenic astrocytes in the subventricular zone (SVZ), whereas GFAP(+1) is found in a subset of astrocytes throughout the brain. In addition, the expression of these isoforms in human brain material of epilepsy, Alzheimer and glioma patients has been reported. Here, for the first time, we present a comprehensive study of GFAP isoform expression in both wild-type and Alzheimer Disease (AD) mouse models. In cortex, cerebellum, and striatum of wild-type mice, transcripts for Gfap-α, Gfap-β, Gfap-γ, Gfap-δ, Gfap-κ, and a newly identified isoform Gfap-ζ, were detected. Their relative expression levels were similar in all regions studied. GFAPα showed a widespread expression whilst GFAPδ distribution was prominent in the SVZ, rostral migratory stream (RMS), neurogenic astrocytes of the subgranular zone (SGZ), and subpial astrocytes. In contrast to the human SVZ, we could not establish an unambiguous GFAPδ localization in proliferating cells of the mouse SVZ. In APPswePS1dE9 and 3xTgAD mice, plaque-associated reactive astrocytes had increased transcript levels of all detectable GFAP isoforms and low levels of a new GFAP isoform, Gfap-ΔEx7. Reactive astrocytes in AD mice showed enhanced GFAPα and GFAPδ immunolabeling, less frequently increased vimentin and nestin, but no GFAPκ or GFAP(+1) staining. In conclusion, GFAPδ protein is present in SVZ, RMS, and neurogenic astrocytes of the SGZ, but also outside neurogenic niches. Furthermore, differential GFAP isoform expression is not linked with aging or reactive gliosis. This evidence points to the conclusion that differential regulation of GFAP isoforms is not involved in the reorganization of the IF network in reactive gliosis or in neurogenesis in the mouse brain.
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Affiliation(s)
- Willem Kamphuis
- Netherlands Institute for Neuroscience - an Institute of the Royal Netherlands Academy of Arts and Sciences, Department of Astrocyte Biology & Neurodegeneration, Amsterdam, The Netherlands.
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Application of Mutant IDH1 Antibody to Differentiate Diffuse Glioma From Nonneoplastic Central Nervous System Lesions and Therapy-induced Changes. Am J Surg Pathol 2010; 34:1199-204. [DOI: 10.1097/pas.0b013e3181e7740d] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Immunohistochemical characterization of the out-of frame splice variants GFAP Δ164/Δexon 6 in focal lesions associated with chronic epilepsy. Epilepsy Res 2010; 90:99-109. [DOI: 10.1016/j.eplepsyres.2010.03.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2009] [Revised: 03/24/2010] [Accepted: 03/31/2010] [Indexed: 11/19/2022]
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Sofroniew MV, Vinters HV. Astrocytes: biology and pathology. Acta Neuropathol 2010; 119:7-35. [PMID: 20012068 PMCID: PMC2799634 DOI: 10.1007/s00401-009-0619-8] [Citation(s) in RCA: 3431] [Impact Index Per Article: 245.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2009] [Revised: 11/23/2009] [Accepted: 11/24/2009] [Indexed: 02/06/2023]
Abstract
Astrocytes are specialized glial cells that outnumber neurons by over fivefold. They contiguously tile the entire central nervous system (CNS) and exert many essential complex functions in the healthy CNS. Astrocytes respond to all forms of CNS insults through a process referred to as reactive astrogliosis, which has become a pathological hallmark of CNS structural lesions. Substantial progress has been made recently in determining functions and mechanisms of reactive astrogliosis and in identifying roles of astrocytes in CNS disorders and pathologies. A vast molecular arsenal at the disposal of reactive astrocytes is being defined. Transgenic mouse models are dissecting specific aspects of reactive astrocytosis and glial scar formation in vivo. Astrocyte involvement in specific clinicopathological entities is being defined. It is now clear that reactive astrogliosis is not a simple all-or-none phenomenon but is a finely gradated continuum of changes that occur in context-dependent manners regulated by specific signaling events. These changes range from reversible alterations in gene expression and cell hypertrophy with preservation of cellular domains and tissue structure, to long-lasting scar formation with rearrangement of tissue structure. Increasing evidence points towards the potential of reactive astrogliosis to play either primary or contributing roles in CNS disorders via loss of normal astrocyte functions or gain of abnormal effects. This article reviews (1) astrocyte functions in healthy CNS, (2) mechanisms and functions of reactive astrogliosis and glial scar formation, and (3) ways in which reactive astrocytes may cause or contribute to specific CNS disorders and lesions.
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