1
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Lin NH, Jian WS, Snider N, Perng MD. Glial fibrillary acidic protein is pathologically modified in Alexander disease. J Biol Chem 2024; 300:107402. [PMID: 38782207 PMCID: PMC11259701 DOI: 10.1016/j.jbc.2024.107402] [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: 02/16/2024] [Revised: 04/29/2024] [Accepted: 05/01/2024] [Indexed: 05/25/2024] Open
Abstract
Here, we describe pathological events potentially involved in the disease pathogenesis of Alexander disease (AxD). This is a primary genetic disorder of astrocyte caused by dominant gain-of-function mutations in the gene coding for an intermediate filament protein glial fibrillary acidic protein (GFAP). Pathologically, this disease is characterized by the upregulation of GFAP and its accumulation as Rosenthal fibers. Although the genetic basis linking GFAP mutations with Alexander disease has been firmly established, the initiating events that promote GFAP accumulation and the role of Rosenthal fibers (RFs) in the disease process remain unknown. Here, we investigate the hypothesis that disease-associated mutations promote GFAP aggregation through aberrant posttranslational modifications. We found high molecular weight GFAP species in the RFs of AxD brains, indicating abnormal GFAP crosslinking as a prominent pathological feature of this disease. In vitro and cell-based studies demonstrate that cystine-generating mutations promote GFAP crosslinking by cysteine-dependent oxidation, resulting in defective GFAP assembly and decreased filament solubility. Moreover, we found GFAP was ubiquitinated in RFs of AxD patients and rodent models, supporting this modification as a critical factor linked to GFAP aggregation. Finally, we found that arginine could increase the solubility of aggregation-prone mutant GFAP by decreasing its ubiquitination and aggregation. Our study suggests a series of pathogenic events leading to AxD, involving interplay between GFAP aggregation and abnormal modifications by GFAP ubiquitination and oxidation. More important, our findings provide a basis for investigating new strategies to treat AxD by targeting abnormal GFAP modifications.
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Affiliation(s)
- Ni-Hsuan Lin
- Institute of Molecular Medicine, National Tsing Hua University, Hsinchu, Taiwan
| | - Wan-Syuan Jian
- Institute of Molecular Medicine, National Tsing Hua University, Hsinchu, Taiwan
| | - Natasha Snider
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Ming-Der Perng
- Institute of Molecular Medicine, National Tsing Hua University, Hsinchu, Taiwan; School of Medicine, College of Life Sciences and Medicine, National Tsing Hua University, Hsinchu, Taiwan.
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2
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Verkhratsky A, Butt A, Li B, Illes P, Zorec R, Semyanov A, Tang Y, Sofroniew MV. Astrocytes in human central nervous system diseases: a frontier for new therapies. Signal Transduct Target Ther 2023; 8:396. [PMID: 37828019 PMCID: PMC10570367 DOI: 10.1038/s41392-023-01628-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Revised: 08/15/2023] [Accepted: 08/22/2023] [Indexed: 10/14/2023] Open
Abstract
Astroglia are a broad class of neural parenchymal cells primarily dedicated to homoeostasis and defence of the central nervous system (CNS). Astroglia contribute to the pathophysiology of all neurological and neuropsychiatric disorders in ways that can be either beneficial or detrimental to disorder outcome. Pathophysiological changes in astroglia can be primary or secondary and can result in gain or loss of functions. Astroglia respond to external, non-cell autonomous signals associated with any form of CNS pathology by undergoing complex and variable changes in their structure, molecular expression, and function. In addition, internally driven, cell autonomous changes of astroglial innate properties can lead to CNS pathologies. Astroglial pathophysiology is complex, with different pathophysiological cell states and cell phenotypes that are context-specific and vary with disorder, disorder-stage, comorbidities, age, and sex. Here, we classify astroglial pathophysiology into (i) reactive astrogliosis, (ii) astroglial atrophy with loss of function, (iii) astroglial degeneration and death, and (iv) astrocytopathies characterised by aberrant forms that drive disease. We review astroglial pathophysiology across the spectrum of human CNS diseases and disorders, including neurotrauma, stroke, neuroinfection, autoimmune attack and epilepsy, as well as neurodevelopmental, neurodegenerative, metabolic and neuropsychiatric disorders. Characterising cellular and molecular mechanisms of astroglial pathophysiology represents a new frontier to identify novel therapeutic strategies.
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Affiliation(s)
- Alexei Verkhratsky
- International Joint Research Centre on Purinergic Signalling/School of Health and Rehabilitation, Chengdu University of Traditional Chinese Medicine, Chengdu, China.
- Department of Forensic Analytical Toxicology, School of Forensic Medicine, China Medical University, Shenyang, China.
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK.
- Achucarro Centre for Neuroscience, IKERBASQUE, Basque Foundation for Science, Bilbao, Spain.
- Department of Stem Cell Biology, State Research Institute Centre for Innovative Medicine, LT-01102, Vilnius, Lithuania.
| | - Arthur Butt
- Institute of Biomedical and Biomolecular Sciences, School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, UK
| | - Baoman Li
- Department of Forensic Analytical Toxicology, School of Forensic Medicine, China Medical University, Shenyang, China
| | - Peter Illes
- International Joint Research Centre on Purinergic Signalling/School of Health and Rehabilitation, Chengdu University of Traditional Chinese Medicine, Chengdu, China
- Rudolf Boehm Institute for Pharmacology and Toxicology, University of Leipzig, 04109, Leipzig, Germany
| | - Robert Zorec
- Celica Biomedical, Lab Cell Engineering, Technology Park, 1000, Ljubljana, Slovenia
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, University of Ljubljana, Faculty of Medicine, Ljubljana, Slovenia
| | - Alexey Semyanov
- Department of Physiology, Jiaxing University College of Medicine, 314033, Jiaxing, China
| | - Yong Tang
- International Joint Research Centre on Purinergic Signalling/School of Health and Rehabilitation, Chengdu University of Traditional Chinese Medicine, Chengdu, China.
- Key Laboratory of Acupuncture for Senile Disease (Chengdu University of TCM), Ministry of Education/Acupuncture and Chronobiology Key Laboratory of Sichuan Province, Chengdu, China.
| | - Michael V Sofroniew
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.
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3
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Pajares MA, Hernández-Gerez E, Pekny M, Pérez-Sala D. Alexander disease: the road ahead. Neural Regen Res 2023; 18:2156-2160. [PMID: 37056123 DOI: 10.4103/1673-5374.369097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/15/2023] Open
Abstract
Alexander disease is a rare neurodegenerative disorder caused by mutations in the glial fibrillary acidic protein, a type III intermediate filament protein expressed in astrocytes. Both early (infantile or juvenile) and adult onsets of the disease are known and, in both cases, astrocytes present characteristic aggregates, named Rosenthal fibers. Mutations are spread along the glial fibrillary acidic protein sequence disrupting the typical filament network in a dominant manner. Although the presence of aggregates suggests a proteostasis problem of the mutant forms, this behavior is also observed when the expression of wild-type glial fibrillary acidic protein is increased. Additionally, several isoforms of glial fibrillary acidic protein have been described to date, while the impact of the mutations on their expression and proportion has not been exhaustively studied. Moreover, the posttranslational modification patterns and/or the protein-protein interaction networks of the glial fibrillary acidic protein mutants may be altered, leading to functional changes that may modify the morphology, positioning, and/or the function of several organelles, in turn, impairing astrocyte normal function and subsequently affecting neurons. In particular, mitochondrial function, redox balance and susceptibility to oxidative stress may contribute to the derangement of glial fibrillary acidic protein mutant-expressing astrocytes. To study the disease and to develop putative therapeutic strategies, several experimental models have been developed, a collection that is in constant growth. The fact that most cases of Alexander disease can be related to glial fibrillary acidic protein mutations, together with the availability of new and more relevant experimental models, holds promise for the design and assay of novel therapeutic strategies.
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Affiliation(s)
- María A Pajares
- Department of Structural and Chemical Biology, Centro de Investigaciones Biológicas Margarita Salas, Madrid, Spain
| | - Elena Hernández-Gerez
- Department of Structural and Chemical Biology, Centro de Investigaciones Biológicas Margarita Salas, Madrid, Spain
| | - Milos Pekny
- Laboratory of Astrocyte Biology and CNS Regeneration, Center for Brain Repair, Department of Clinical Neuroscience, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden; University of Newcastle, Newcastle, NSW, and the Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
| | - Dolores Pérez-Sala
- Department of Structural and Chemical Biology, Centro de Investigaciones Biológicas Margarita Salas, Madrid, Spain
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4
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Doganyigit Z, Eroglu E, Okan A. Intermediate filament proteins are reliable immunohistological biomarkers to help diagnose multiple tissue-specific diseases. Anat Histol Embryol 2023; 52:655-672. [PMID: 37329162 DOI: 10.1111/ahe.12937] [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: 11/27/2022] [Revised: 05/18/2023] [Accepted: 05/31/2023] [Indexed: 06/18/2023]
Abstract
Cytoskeletal networks are proteins that effectively maintain cell integrity and provide mechanical support to cells by actively transmitting mechanical signals. Intermediate filaments, which are from the cytoskeleton family and are 10 nanometres in diameter, are unlike actin and microtubules, which are highly dynamic cytoskeletal elements. Intermediate filaments are flexible at low strain, harden at high strain and resist breaking. For this reason, these filaments fulfil structural functions by providing mechanical support to the cells through their different strain-hardening properties. Intermediate filaments are suitable in that cells both cope with mechanical forces and modulate signal transmission. These filaments are composed of fibrous proteins that exhibit a central α-helical rod domain with a conserved substructure. Intermediate filament proteins are divided into six groups. Type I and type II include acidic and basic keratins, type III, vimentin, desmin, peripheralin and glial fibrillary acidic protein (GFAP), respectively. Type IV intermediate filament group includes neurofilament proteins and a fourth neurofilament subunit, α-internexin proteins. Type V consists of lamins located in the nucleus, and the type VI group consists of lens-specific intermediate filaments, CP49/phakinin and filen. Intermediate filament proteins show specific immunoreactivity in differentiating cells and mature cells of various types. Various carcinomas such as colorectal, urothelial and ovarian, diseases such as chronic pancreatitis, cirrhosis, hepatitis and cataract have been associated with intermediate filaments. Accordingly, this section reviews available immunohistochemical antibodies to intermediate filament proteins. Identification of intermediate filament proteins by methodological methods may contribute to the understanding of complex diseases.
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Affiliation(s)
- Zuleyha Doganyigit
- Faculty of Medicine, Histology and Embryology, Yozgat Bozok University, Yozgat, Turkey
| | - Ece Eroglu
- Faculty of Medicine, Yozgat Bozok University, Yozgat, Turkey
| | - Aslı Okan
- Faculty of Medicine, Histology and Embryology, Yozgat Bozok University, Yozgat, Turkey
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Plectin in the Central Nervous System and a Putative Role in Brain Astrocytes. Cells 2021; 10:cells10092353. [PMID: 34572001 PMCID: PMC8464768 DOI: 10.3390/cells10092353] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 09/03/2021] [Accepted: 09/07/2021] [Indexed: 11/17/2022] Open
Abstract
Plectin, a high-molecular-mass cytolinker, is abundantly expressed in the central nervous system (CNS). Currently, a limited amount of data about plectin in the CNS prevents us from seeing the complete picture of how plectin affects the functioning of the CNS as a whole. Yet, by analogy to its role in other tissues, it is anticipated that, in the CNS, plectin also functions as the key cytoskeleton interlinking molecule. Thus, it is likely involved in signalling processes, thereby affecting numerous fundamental functions in the brain and spinal cord. Versatile direct and indirect interactions of plectin with cytoskeletal filaments and enzymes in the cells of the CNS in normal physiological and in pathologic conditions remain to be fully addressed. Several pathologies of the CNS related to plectin have been discovered in patients with plectinopathies. However, in view of plectin as an integrator of a cohesive mesh of cellular proteins, it is important that the role of plectin is also considered in other CNS pathologies. This review summarizes the current knowledge of plectin in the CNS, focusing on plectin isoforms that have been detected in the CNS, along with its expression profile and distribution alongside diverse cytoskeleton filaments in CNS cell types. Considering that the bidirectional communication between neurons and glial cells, especially astrocytes, is crucial for proper functioning of the CNS, we place particular emphasis on the known roles of plectin in neurons, and we propose possible roles of plectin in astrocytes.
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Pekna M, Pekny M. The Complement System: A Powerful Modulator and Effector of Astrocyte Function in the Healthy and Diseased Central Nervous System. Cells 2021; 10:cells10071812. [PMID: 34359981 PMCID: PMC8303424 DOI: 10.3390/cells10071812] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 07/08/2021] [Accepted: 07/14/2021] [Indexed: 12/11/2022] Open
Abstract
The complement system, an effector arm of the innate immune system that plays a critical role in tissue inflammation, the elimination of pathogens and the clearance of dead cells and cell debris, has emerged as a regulator of many processes in the central nervous system, including neural cell genesis and migration, control of synapse number and function, and modulation of glial cell responses. Complement dysfunction has also been put forward as a major contributor to neurological disease. Astrocytes are neuroectoderm-derived glial cells that maintain water and ionic homeostasis, and control cerebral blood flow and multiple aspects of neuronal functioning. By virtue of their expression of soluble as well as membrane-bound complement proteins and receptors, astrocytes are able to both send and receive complement-related signals. Here we review the current understanding of the multiple functions of the complement system in the central nervous system as they pertain to the modulation of astrocyte activity, and how astrocytes use the complement system to affect their environment in the healthy brain and in the context of neurological disease.
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Affiliation(s)
- Marcela Pekna
- Laboratory of Regenerative Neuroimmunology, Center for Brain Repair, Department of Clinical Neuroscience, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, 40530 Gothenburg, Sweden
- Florey Institute of Neuroscience and Mental Health, Parkville, Melbourne 3010, Australia
- School of Medicine and Public Health, University of Newcastle, Newcastle 2308, Australia
- Correspondence: ; Tel.: +46-31-786-3581
| | - Milos Pekny
- Laboratory of Astrocyte Biology and CNS Regeneration, Center for Brain Repair, Department of Clinical Neuroscience, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, 40530 Gothenburg, Sweden;
- Florey Institute of Neuroscience and Mental Health, Parkville, Melbourne 3010, Australia
- School of Medicine and Public Health, University of Newcastle, Newcastle 2308, Australia
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7
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Potokar M, Morita M, Wiche G, Jorgačevski J. The Diversity of Intermediate Filaments in Astrocytes. Cells 2020; 9:E1604. [PMID: 32630739 PMCID: PMC7408014 DOI: 10.3390/cells9071604] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 06/26/2020] [Accepted: 07/01/2020] [Indexed: 01/02/2023] Open
Abstract
Despite the remarkable complexity of the individual neuron and of neuronal circuits, it has been clear for quite a while that, in order to understand the functioning of the brain, the contribution of other cell types in the brain have to be accounted for. Among glial cells, astrocytes have multiple roles in orchestrating neuronal functions. Their communication with neurons by exchanging signaling molecules and removing molecules from extracellular space takes place at several levels and is governed by different cellular processes, supported by multiple cellular structures, including the cytoskeleton. Intermediate filaments in astrocytes are emerging as important integrators of cellular processes. Astrocytes express five types of intermediate filaments: glial fibrillary acidic protein (GFAP); vimentin; nestin; synemin; lamins. Variability, interactions with different cellular structures and the particular roles of individual intermediate filaments in astrocytes have been studied extensively in the case of GFAP and vimentin, but far less attention has been given to nestin, synemin and lamins. Similarly, the interplay between different types of cytoskeleton and the interaction between the cytoskeleton and membranous structures, which is mediated by cytolinker proteins, are understudied in astrocytes. The present review summarizes the basic properties of astrocytic intermediate filaments and of other cytoskeletal macromolecules, such as cytolinker proteins, and describes the current knowledge of their roles in normal physiological and pathological conditions.
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Affiliation(s)
- Maja Potokar
- Laboratory of Neuroendocrinology – Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia;
- Celica BIOMEDICAL, 1000 Ljubljana, Slovenia;
| | - Mitsuhiro Morita
- Department of Biology, Kobe University Graduate School of Science, Kobe 657-8501, Japan;
| | - Gerhard Wiche
- Celica BIOMEDICAL, 1000 Ljubljana, Slovenia;
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, 1030 Vienna, Austria
| | - Jernej Jorgačevski
- Laboratory of Neuroendocrinology – Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia;
- Celica BIOMEDICAL, 1000 Ljubljana, Slovenia;
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8
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Russell MA. Synemin Redefined: Multiple Binding Partners Results in Multifunctionality. Front Cell Dev Biol 2020; 8:159. [PMID: 32258037 PMCID: PMC7090255 DOI: 10.3389/fcell.2020.00159] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 02/27/2020] [Indexed: 12/15/2022] Open
Abstract
Historically synemin has been studied as an intermediate filament protein. However, synemin also binds the type II regulatory (R) subunit α of protein kinase A (PKA) and protein phosphatase type 2A, thus participating in the PKA and phosphoinositide 3-kinase (PI3K)-Akt and signaling pathways. In addition, recent studies using transgenic mice indicate that a significant function of synemin is its role in signaling pathways in various tissues, including the heart. Recent clinical reports have shown that synemin mutations led to multiple cases of dilated cardiomyopathy. Additionally, a single case of the rare condition ulnar-mammary-like syndrome with left ventricular tachycardia due to a mutation in the synemin gene (SYNM) has been reported. Therefore, this review uses these recent studies to provide a new framework for detailed discussions on synemin tissue distribution, binding partners and synemin in disease. Differences between α- and β-synemin are highlighted. The studies presented here indicate that while synemin does function as an intermediate filament protein, it is unique among this large family of proteins as it is also a regulator of signaling pathways and a crosslinker. Also evident is that the dominant function(s) are isoform-, developmental-, and tissue-specific.
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Affiliation(s)
- Mary A Russell
- Department of Biological Sciences, Kent State University at Trumbull, Warren, OH, United States
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Paulin D, Hovhannisyan Y, Kasakyan S, Agbulut O, Li Z, Xue Z. Synemin-related skeletal and cardiac myopathies: an overview of pathogenic variants. Am J Physiol Cell Physiol 2020; 318:C709-C718. [PMID: 32023076 DOI: 10.1152/ajpcell.00485.2019] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
This review analyzes data concerning patients with cardiomyopathies or skeletal myopathies associated with a variation in the intermediate filament (IF) synemin gene (SYNM), also referred to as desmuslin (DMN). Molecular studies demonstrate that synemin copolymerizes with desmin and vimentin IF and interacts with vinculin, α-actinin, α-dystrobrevin, dystrophin, talin, and zyxin. It has been found that synemin is an A-kinase-anchoring protein (AKAP) that anchors protein kinase A (PKA) and modulates the PKA-dependent phosphorylation of several cytoskeletal substrates such as desmin. Because several IF proteins, including desmin, have been implicated in human genetic disorders such as dominant or recessive congenital and adult-onset myopathy, synemin becomes a significant candidate for cardiac and skeletal myopathies of unknown etiology. Because SYNM is a new candidate gene that displays numerous sequence polymorphisms, in this review, we summarize the genetic and clinical literature about SYNM mutations. Protein-changing variants (missense, frameshifts, nonsense) were further evaluated based on structural modifications and amino acid interactions. We present in silico modeling of helical salt-bridges between residues to evaluate the impact of the synemin networks crucial to interactions with cytoskeletal proteins. Finally, a discussion is featured regarding certain variants that may contribute to the disease state.
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Affiliation(s)
- Denise Paulin
- Sorbonne Université, Institut de Biologie Paris-Seine, CNRS UMR 8256, INSERM ERL U1164, Biological Adaptation and Ageing, Paris, France
| | - Yeranuhi Hovhannisyan
- Sorbonne Université, Institut de Biologie Paris-Seine, CNRS UMR 8256, INSERM ERL U1164, Biological Adaptation and Ageing, Paris, France
| | - Serdar Kasakyan
- Duzen Laboratories Group, Center of Genetic Diagnosis, Istanbul, Turkey
| | - Onnik Agbulut
- Sorbonne Université, Institut de Biologie Paris-Seine, CNRS UMR 8256, INSERM ERL U1164, Biological Adaptation and Ageing, Paris, France
| | - Zhenlin Li
- Sorbonne Université, Institut de Biologie Paris-Seine, CNRS UMR 8256, INSERM ERL U1164, Biological Adaptation and Ageing, Paris, France
| | - Zhigang Xue
- Sorbonne Université, Institut de Biologie Paris-Seine, CNRS UMR 8256, INSERM ERL U1164, Biological Adaptation and Ageing, Paris, France
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Jones JR, Kong L, Hanna MG, Hoffman B, Krencik R, Bradley R, Hagemann T, Choi J, Doers M, Dubovis M, Sherafat MA, Bhattacharyya A, Kendziorski C, Audhya A, Messing A, Zhang SC. Mutations in GFAP Disrupt the Distribution and Function of Organelles in Human Astrocytes. Cell Rep 2019; 25:947-958.e4. [PMID: 30355500 PMCID: PMC6275075 DOI: 10.1016/j.celrep.2018.09.083] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 09/05/2018] [Accepted: 09/25/2018] [Indexed: 01/15/2023] Open
Abstract
How mutations in glial fibrillary acidic protein (GFAP) cause Alexander disease (AxD) remains elusive. We generated iPSCs from two AxD patients and corrected the GFAP mutations to examine the effects of mutant GFAP on human astrocytes. AxD astrocytes displayed GFAP aggregates, recapitulating the pathological hallmark of AxD. RNA sequencing implicated the endoplasmic reticulum, vesicle regulation, and cellular metabolism. Corroborating this analysis, we observed enlarged and heterogeneous morphology coupled with perinuclear localization of endoplasmic reticulum and lysosomes in AxD astrocytes. Functionally, AxD astrocytes showed impaired extracellular ATP release, which is responsible for attenuated calcium wave propagation. These results reveal that AxD-causing mutations in GFAP disrupt intracellular vesicle regulation and impair astrocyte secretion, resulting in astrocyte dysfunction and AxD pathogenesis.
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Affiliation(s)
- Jeffrey R Jones
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Molecular and Cellular Pharmacology Training Program, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Linghai Kong
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Michael G Hanna
- Molecular and Cellular Pharmacology Training Program, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Brianna Hoffman
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Robert Krencik
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Robert Bradley
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Tracy Hagemann
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Jeea Choi
- Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Matthew Doers
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Marina Dubovis
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
| | | | | | - Christina Kendziorski
- Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Anjon Audhya
- Molecular and Cellular Pharmacology Training Program, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Albee Messing
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Su-Chun Zhang
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Neurology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA; Program in Neuroscience & Behavioral Disorders, Duke-NUS Medical School, Singapore, Singapore.
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Abstract
Astrocytes are neural cells of ectodermal, neuroepithelial origin that provide for homeostasis and defense of the central nervous system (CNS). Astrocytes are highly heterogeneous in morphological appearance; they express a multitude of receptors, channels, and membrane transporters. This complement underlies their remarkable adaptive plasticity that defines the functional maintenance of the CNS in development and aging. Astrocytes are tightly integrated into neural networks and act within the context of neural tissue; astrocytes control homeostasis of the CNS at all levels of organization from molecular to the whole organ.
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Affiliation(s)
- Alexei Verkhratsky
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
| | - Maiken Nedergaard
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
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12
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Verkhratsky A, Nedergaard M. Physiology of Astroglia. Physiol Rev 2018; 98:239-389. [PMID: 29351512 PMCID: PMC6050349 DOI: 10.1152/physrev.00042.2016] [Citation(s) in RCA: 928] [Impact Index Per Article: 154.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 03/22/2017] [Accepted: 04/27/2017] [Indexed: 02/07/2023] Open
Abstract
Astrocytes are neural cells of ectodermal, neuroepithelial origin that provide for homeostasis and defense of the central nervous system (CNS). Astrocytes are highly heterogeneous in morphological appearance; they express a multitude of receptors, channels, and membrane transporters. This complement underlies their remarkable adaptive plasticity that defines the functional maintenance of the CNS in development and aging. Astrocytes are tightly integrated into neural networks and act within the context of neural tissue; astrocytes control homeostasis of the CNS at all levels of organization from molecular to the whole organ.
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Affiliation(s)
- Alexei Verkhratsky
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
| | - Maiken Nedergaard
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
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Lin NH, Messing A, Perng MD. Characterization of a panel of monoclonal antibodies recognizing specific epitopes on GFAP. PLoS One 2017; 12:e0180694. [PMID: 28700643 PMCID: PMC5503259 DOI: 10.1371/journal.pone.0180694] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2017] [Accepted: 06/20/2017] [Indexed: 11/19/2022] Open
Abstract
Alexander disease (AxD) is a neurodegenerative disease caused by heterozygous mutations in the GFAP gene, which encodes the major intermediate filament protein of astrocytes. This disease is characterized by the accumulation of cytoplasmic protein aggregates, known as Rosenthal fibers. Antibodies specific to GFAP could provide invaluable tools to facilitate studies of the normal biology of GFAP and to elucidate the pathologic role of this IF protein in disease. While a large number of antibodies to GFAP are available, few if any of them have defined epitopes. Here we described the characterization of a panel of commonly used anti-GFAP antibodies, which recognized epitopes at regions extending across the rod domain of GFAP. We show that all of the antibodies are useful for immunoblotting and immunostaining, and identify a subset that preferentially recognized human GFAP. Using these antibodies, we demonstrate the presence of biochemically modified forms of GFAP in brains of human AxD patients and mouse AxD models. These data suggest that this panel of anti-GFAP antibodies will be useful for studies of animal and cell-based models of AxD and related diseases in which cytoskeletal defects associated with GFAP modifications occur.
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Affiliation(s)
- Ni-Hsuan Lin
- Institute of Molecular Medicine, College of Life Sciences, National Tsing Hua University, Hsinchu, Taiwan
| | - Albee Messing
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Ming-Der Perng
- Institute of Molecular Medicine, College of Life Sciences, National Tsing Hua University, Hsinchu, Taiwan
- * E-mail:
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14
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Sosunov AA, McKhann GM, Goldman JE. The origin of Rosenthal fibers and their contributions to astrocyte pathology in Alexander disease. Acta Neuropathol Commun 2017; 5:27. [PMID: 28359321 PMCID: PMC5374671 DOI: 10.1186/s40478-017-0425-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 03/08/2017] [Indexed: 11/27/2022] Open
Abstract
Rosenthal fibers (RFs) are cytoplasmic, proteinaceous aggregates. They are the pathognomonic feature of the astrocyte pathology in Alexander Disease (AxD), a neurodegenerative disorder caused by heterozygous mutations in the GFAP gene, encoding glial fibrillary acidic protein (GFAP). Although RFs have been known for many years their origin and significance remain elusive issues. We have used mouse models of AxD based on the overexpression of human GFAP (transgenic, TG) and a point mutation in mouse GFAP (knock-in, KI) to examine the formation of RFs and to find astrocyte changes that correlate with the appearance of RFs. We found RFs of various sizes and shapes. The smallest ones appear as granular depositions on intermediate filaments. These contain GFAP and the small heat shock protein, alphaB-crystallin. Their aggregation appears to give rise to large RFs. The appearance of new RFs and the growth of previously formed RFs occur over time. We determined that DAPI is a reliable marker of RFs and in parallel with Fluoro-Jade B (FJB) staining defined a high variability in the appearance of RFs, even in neighboring astrocytes. Although many astrocytes in AxD with increased levels of GFAP and with or without RFs change their phenotype, only some cells with large numbers of RFs show a profound reconstruction of cellular processes, with a loss of fine distal processes and the appearance of large, lobulated nuclei, likely due to arrested mitosis. We conclude that 1) RFs appear to originate as small, osmiophilic masses containing both GFAP and alphaB-crystallin deposited on bundles of intermediate filaments. 2) RFs continue to form within AxD astrocytes over time. 3) DAPI is a reliable marker for RFs and can be used with immunolabeling. 4) RFs appear to interfere with the successful completion of astrocyte mitosis and cell division.
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15
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Heaven MR, Flint D, Randall SM, Sosunov AA, Wilson L, Barnes S, Goldman JE, Muddiman DC, Brenner M. Composition of Rosenthal Fibers, the Protein Aggregate Hallmark of Alexander Disease. J Proteome Res 2016; 15:2265-82. [PMID: 27193225 PMCID: PMC5036859 DOI: 10.1021/acs.jproteome.6b00316] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Alexander disease (AxD) is a neurodegenerative disorder characterized by astrocytic protein aggregates called Rosenthal fibers (RFs). We used mouse models of AxD to determine the protein composition of RFs to obtain information about disease mechanisms including the hypothesis that sequestration of proteins in RFs contributes to disease. A method was developed for RF enrichment, and analysis of the resulting fraction using isobaric tags for relative and absolute quantitation mass spectrometry identified 77 proteins not previously associated with RFs. Three of five proteins selected for follow-up were confirmed enriched in the RF fraction by immunobloting of both the AxD mouse models and human patients: receptor for activated protein C kinase 1 (RACK1), G1/S-specific cyclin D2, and ATP-dependent RNA helicase DDX3X. Immunohistochemistry validated cyclin D2 as a new RF component, but results for RACK1 and DDX3X were equivocal. None of these was decreased in the non-RF fractions compared to controls. A similar result was obtained for the previously known RF component, alphaB-crystallin, which had been a candidate for sequestration. Thus, no support was obtained for the sequestration hypothesis for AxD. Providing possible insight into disease progression, the association of several of the RF proteins with stress granules suggests a role for stress granules in the origin of RFs.
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Affiliation(s)
- Michael R. Heaven
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Alabama 35294
| | - Daniel Flint
- Department of Neurobiology and the Civitan International Research Center, Center for Glial Biology in Medicine, Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Shan M. Randall
- Keck Fourier Transform Mass Spectrometry Laboratory, Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695
| | | | - Landon Wilson
- Department of Pharmacology and Toxicology, Targeted Metabolomics and Proteomics Laboratory, University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Stephen Barnes
- Department of Pharmacology and Toxicology, Targeted Metabolomics and Proteomics Laboratory, University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - James E. Goldman
- Department of Pathology & Cell Biology, Columbia University, New York, New York, 10032
| | - David C. Muddiman
- Keck Fourier Transform Mass Spectrometry Laboratory, Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695
| | - Michael Brenner
- Department of Neurobiology and the Civitan International Research Center, Center for Glial Biology in Medicine, Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, Alabama 35294
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16
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Astrocytes: a central element in neurological diseases. Acta Neuropathol 2016; 131:323-45. [PMID: 26671410 DOI: 10.1007/s00401-015-1513-1] [Citation(s) in RCA: 536] [Impact Index Per Article: 67.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 10/28/2015] [Accepted: 11/21/2015] [Indexed: 12/18/2022]
Abstract
The neurone-centred view of the past disregarded or downplayed the role of astroglia as a primary component in the pathogenesis of neurological diseases. As this concept is changing, so is also the perceived role of astrocytes in the healthy and diseased brain and spinal cord. We have started to unravel the different signalling mechanisms that trigger specific molecular, morphological and functional changes in reactive astrocytes that are critical for repairing tissue and maintaining function in CNS pathologies, such as neurotrauma, stroke, or neurodegenerative diseases. An increasing body of evidence shows that the effects of astrogliosis on the neural tissue and its functions are not uniform or stereotypic, but vary in a context-specific manner from astrogliosis being an adaptive beneficial response under some circumstances to a maladaptive and deleterious process in another context. There is a growing support for the concept of astrocytopathies in which the disruption of normal astrocyte functions, astrodegeneration or dysfunctional/maladaptive astrogliosis are the primary cause or the main factor in neurological dysfunction and disease. This review describes the multiple roles of astrocytes in the healthy CNS, discusses the diversity of astroglial responses in neurological disorders and argues that targeting astrocytes may represent an effective therapeutic strategy for Alexander disease, neurotrauma, stroke, epilepsy and Alzheimer's disease as well as other neurodegenerative diseases.
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17
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18
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Electro-acupuncture at LI11 and ST36 acupoints exerts neuroprotective effects via reactive astrocyte proliferation after ischemia and reperfusion injury in rats. Brain Res Bull 2015; 120:14-24. [PMID: 26524137 DOI: 10.1016/j.brainresbull.2015.10.011] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2015] [Revised: 10/22/2015] [Accepted: 10/26/2015] [Indexed: 11/23/2022]
Abstract
Reactive astrogliosis is a common phenomenon in central nervous system (CNS) injuries such as ischemic stroke. The present study aimed to deeply investigate the relationships between the neuroprotective effect of electro-acupuncture (EA) and reactive astrocytes following cerebral ischemia. EA treatment at the Quchi (LI11) and Zusanli (ST36) acupoints at Day 3 attenuated neurological deficits and cerebral infarct volume in ischemia and reperfusion (I/R) injured rats. Animal behavior assessments found that the speed of Catwalk gait, equilibrium and coordination of Rotarod test were improved. Furthermore, EA treatment exerted neuroprotective effects via activation of glial fibrillary acidic protein (GFAP), vimentin and nestin positive cells. Simultaneously, an obvious increase in GFAP/vimentin, GFAP/nestin and GFAP/BrdU co-labeling appeared in the peri-infract cortex and striatum, suggesting EA can promote the proliferation of GFAP/vimentin/nestin-positive reactive astrocytes. The expression of cell cycle-associated proteins Cyclin Dl, CDK4 and phospho-Rb were increased in the peri-infract cortex and striatum, indicating proliferated reactive astrocytes-mediated CyclinDl/CDK4 regulation of the transition of the G1-to-S cell cycle phases. In addition, EA enhanced the localized expression of brain-derived neurotrophic factor (BDNF) in the peri-infract cortex and striatum. These results demonstrated that EA treatment at the LI11 and ST36 acupoints on Day 3 exerted neuroprotection via proliferation of GFAP/vimentin/nestin-positive reactive astrocytes and, potentially, secretion of reactive astrocytes-derived BDNF in I/R injured rats.
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19
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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: 539] [Impact Index Per Article: 59.9] [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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20
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García-Pelagio KP, Muriel J, O'Neill A, Desmond PF, Lovering RM, Lund L, Bond M, Bloch RJ. Myopathic changes in murine skeletal muscle lacking synemin. Am J Physiol Cell Physiol 2015; 308:C448-62. [PMID: 25567810 DOI: 10.1152/ajpcell.00331.2014] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Diseases of striated muscle linked to intermediate filament (IF) proteins are associated with defects in the organization of the contractile apparatus and its links to costameres, which connect the sarcomeres to the cell membrane. Here we study the role in skeletal muscle of synemin, a type IV IF protein, by examining mice null for synemin (synm-null). Synm-null mice have a mild skeletal muscle phenotype. Tibialis anterior (TA) muscles show a significant decrease in mean fiber diameter, a decrease in twitch and tetanic force, and an increase in susceptibility to injury caused by lengthening contractions. Organization of proteins associated with the contractile apparatus and costameres is not significantly altered in the synm-null. Elastimetry of the sarcolemma and associated contractile apparatus in extensor digitorum longus myofibers reveals a reduction in tension consistent with an increase in sarcolemmal deformability. Although fatigue after repeated isometric contractions is more marked in TA muscles of synm-null mice, the ability of the mice to run uphill on a treadmill is similar to controls. Our results suggest that synemin contributes to linkage between costameres and the contractile apparatus and that the absence of synemin results in decreased fiber size and increased sarcolemmal deformability and susceptibility to injury. Thus synemin plays a moderate but distinct role in fast twitch skeletal muscle.
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Affiliation(s)
- Karla P García-Pelagio
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, Maryland
| | - Joaquin Muriel
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, Maryland
| | - Andrea O'Neill
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, Maryland
| | - Patrick F Desmond
- Program in Biochemistry and Molecular Biology, School of Medicine, University of Maryland, Baltimore, Maryland
| | - Richard M Lovering
- Department of Orthopaedics, School of Medicine, University of Maryland, Baltimore, Maryland
| | - Linda Lund
- Merrick School of Business, University of Baltimore, Baltimore, Maryland; and
| | - Meredith Bond
- College of Sciences and Health Professions, Cleveland State University, Cleveland, Ohio
| | - Robert J Bloch
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, Maryland;
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21
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Pekny M, Pekna M. Astrocyte reactivity and reactive astrogliosis: costs and benefits. Physiol Rev 2014; 94:1077-98. [PMID: 25287860 DOI: 10.1152/physrev.00041.2013] [Citation(s) in RCA: 606] [Impact Index Per Article: 60.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Astrocytes are the most abundant cells in the central nervous system (CNS) that provide nutrients, recycle neurotransmitters, as well as fulfill a wide range of other homeostasis maintaining functions. During the past two decades, astrocytes emerged also as increasingly important regulators of neuronal functions including the generation of new nerve cells and structural as well as functional synapse remodeling. Reactive gliosis or reactive astrogliosis is a term coined for the morphological and functional changes seen in astroglial cells/astrocytes responding to CNS injury and other neurological diseases. Whereas this defensive reaction of astrocytes is conceivably aimed at handling the acute stress, limiting tissue damage, and restoring homeostasis, it may also inhibit adaptive neural plasticity mechanisms underlying recovery of function. Understanding the multifaceted roles of astrocytes in the healthy and diseased CNS will undoubtedly contribute to the development of treatment strategies that will, in a context-dependent manner and at appropriate time points, modulate reactive astrogliosis to promote brain repair and reduce the neurological impairment.
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Affiliation(s)
- Milos Pekny
- Center for Brain Repair and Rehabilitation, Department of Clinical Neuroscience and Rehabilitation, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden; and Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Marcela Pekna
- Center for Brain Repair and Rehabilitation, Department of Clinical Neuroscience and Rehabilitation, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden; and Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
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22
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Li Z, Parlakian A, Coletti D, Alonso-Martin S, Hourdé C, Joanne P, Gao-Li J, Blanc J, Ferry A, Paulin D, Xue Z, Agbulut O. Synemin acts as a regulator of signalling molecules during skeletal muscle hypertrophy. J Cell Sci 2014; 127:4589-601. [PMID: 25179606 DOI: 10.1242/jcs.143164] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Synemin, a type IV intermediate filament (IF) protein, forms a bridge between IFs and cellular membranes. As an A-kinase-anchoring protein, it also provides temporal and spatial targeting of protein kinase A (PKA). However, little is known about its functional roles in either process. To better understand its functions in muscle tissue, we generated synemin-deficient (Synm(-) (/-)) mice. Synm(-) (/-) mice displayed normal development and fertility but showed a mild degeneration and regeneration phenotype in myofibres and defects in sarcolemma membranes. Following mechanical overload, Synm(-) (/-) mice muscles showed a higher hypertrophic capacity with increased maximal force and fatigue resistance compared with control mice. At the molecular level, increased remodelling capacity was accompanied by decreased myostatin (also known as GDF8) and atrogin (also known as FBXO32) expression, and increased follistatin expression. Furthermore, the activity of muscle-mass control molecules (the PKA RIIα subunit, p70S6K and CREB1) was increased in mutant mice. Finally, analysis of muscle satellite cell behaviour suggested that the absence of synemin could affect the balance between self-renewal and differentiation of these cells. Taken together, our results show that synemin is necessary to maintain membrane integrity and regulates signalling molecules during muscle hypertrophy.
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Affiliation(s)
- Zhenlin Li
- Sorbonne Universités, UPMC Univ Paris 06, UMR CNRS 8256/INSERM ERL U1164, Biological Adaptation and Ageing, Institut de Biologie Paris-Seine, Paris, F-75005 France
| | - Ara Parlakian
- Sorbonne Universités, UPMC Univ Paris 06, UMR CNRS 8256/INSERM ERL U1164, Biological Adaptation and Ageing, Institut de Biologie Paris-Seine, Paris, F-75005 France
| | - Dario Coletti
- Sorbonne Universités, UPMC Univ Paris 06, UMR CNRS 8256/INSERM ERL U1164, Biological Adaptation and Ageing, Institut de Biologie Paris-Seine, Paris, F-75005 France
| | - Sonia Alonso-Martin
- Sorbonne Universités, UPMC Univ-Paris 06, INSERM U974, CNRS UMR7215, Institut de Myologie, Paris-France
| | - Christophe Hourdé
- Sorbonne Universités, UPMC Univ Paris 06, UMR CNRS 8256/INSERM ERL U1164, Biological Adaptation and Ageing, Institut de Biologie Paris-Seine, Paris, F-75005 France
| | - Pierre Joanne
- Sorbonne Universités, UPMC Univ Paris 06, UMR CNRS 8256/INSERM ERL U1164, Biological Adaptation and Ageing, Institut de Biologie Paris-Seine, Paris, F-75005 France
| | - Jacqueline Gao-Li
- Sorbonne Universités, UPMC Univ Paris 06, UMR CNRS 8256/INSERM ERL U1164, Biological Adaptation and Ageing, Institut de Biologie Paris-Seine, Paris, F-75005 France
| | - Jocelyne Blanc
- Sorbonne Universités, UPMC Univ Paris 06, UMR CNRS 8256/INSERM ERL U1164, Biological Adaptation and Ageing, Institut de Biologie Paris-Seine, Paris, F-75005 France
| | - Arnaud Ferry
- Sorbonne Universités, UPMC Univ-Paris 06, INSERM U974, CNRS UMR7215, Institut de Myologie, Paris-France
| | - Denise Paulin
- Sorbonne Universités, UPMC Univ Paris 06, UMR CNRS 8256/INSERM ERL U1164, Biological Adaptation and Ageing, Institut de Biologie Paris-Seine, Paris, F-75005 France
| | - Zhigang Xue
- Sorbonne Universités, UPMC Univ Paris 06, UMR CNRS 8256/INSERM ERL U1164, Biological Adaptation and Ageing, Institut de Biologie Paris-Seine, Paris, F-75005 France
| | - Onnik Agbulut
- Sorbonne Universités, UPMC Univ Paris 06, UMR CNRS 8256/INSERM ERL U1164, Biological Adaptation and Ageing, Institut de Biologie Paris-Seine, Paris, F-75005 France
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23
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Pekny M, Wilhelmsson U, Pekna M. The dual role of astrocyte activation and reactive gliosis. Neurosci Lett 2014; 565:30-8. [PMID: 24406153 DOI: 10.1016/j.neulet.2013.12.071] [Citation(s) in RCA: 477] [Impact Index Per Article: 47.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Revised: 12/21/2013] [Accepted: 12/29/2013] [Indexed: 11/16/2022]
Abstract
Astrocyte activation and reactive gliosis accompany most of the pathologies in the brain, spinal cord, and retina. Reactive gliosis has been described as constitutive, graded, multi-stage, and evolutionary conserved defensive astroglial reaction [Verkhratsky and Butt (2013) In: Glial Physiology and Pathophysiology]. A well- known feature of astrocyte activation and reactive gliosis are the increased production of intermediate filament proteins (also known as nanofilament proteins) and remodeling of the intermediate filament system of astrocytes. Activation of astrocytes is associated with changes in the expression of many genes and characteristic morphological hallmarks, and has important functional consequences in situations such as stroke, trauma, epilepsy, Alzheimer's disease (AD), and other neurodegenerative diseases. The impact of astrocyte activation and reactive gliosis on the pathogenesis of different neurological disorders is not yet fully understood but the available experimental evidence points to many beneficial aspects of astrocyte activation and reactive gliosis that range from isolation and sequestration of the affected region of the central nervous system (CNS) from the neighboring tissue that limits the lesion size to active neuroprotection and regulation of the CNS homeostasis in times of acute ischemic, osmotic, or other kinds of stress. The available experimental data from selected CNS pathologies suggest that if not resolved in time, reactive gliosis can exert inhibitory effects on several aspects of neuroplasticity and CNS regeneration and thus might become a target for future therapeutic interventions.
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Affiliation(s)
- Milos Pekny
- Center for Brain Repair and Rehabilitation, Department of Clinical Neuroscience and Rehabilitation, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Gothenburg SE-405 30, Sweden; Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia.
| | - Ulrika Wilhelmsson
- Center for Brain Repair and Rehabilitation, Department of Clinical Neuroscience and Rehabilitation, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Gothenburg SE-405 30, Sweden
| | - Marcela Pekna
- Center for Brain Repair and Rehabilitation, Department of Clinical Neuroscience and Rehabilitation, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Gothenburg SE-405 30, Sweden; Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
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24
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Lépinoux-Chambaud C, Eyer J. Review on intermediate filaments of the nervous system and their pathological alterations. Histochem Cell Biol 2013; 140:13-22. [PMID: 23749407 DOI: 10.1007/s00418-013-1101-1] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/23/2013] [Indexed: 11/28/2022]
Abstract
Intermediate filaments (IFs) of the nervous system, including neurofilaments, α-internexin, glial fibrillary acidic protein, synemin, nestin, peripherin and vimentin, are finely expressed following elaborated cell, tissue and developmental specific patterns. A common characteristic of several neurodegenerative diseases is the abnormal accumulation of neuronal IFs in cell bodies or along the axon, often associated with impairment of the axonal transport and degeneration of neurons. In this review, we also present several perturbations of IF metabolism and organization associated with neurodegenerative disorders. Such modifications could represent strong markers of neuronal damages. Moreover, recent data suggest that IFs represent potential biomarkers to determine the disease progression or the differential stages of a neuronal disorder. Finally, recent investigations on IF expression and function in cancer provide evidence that they may be useful as markers, or targets of brain tumours, especially high-grade glioma. A better knowledge of the molecular mechanisms of IF alterations, combined to neuroimaging, is essential to improve diagnosis and therapeutic strategies of such neurodegenerative diseases and glioma.
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Affiliation(s)
- Claire Lépinoux-Chambaud
- Laboratoire Neurobiologie and Transgenese, LUNAM, UPRES EA-3143, Centre Hospitalier Universitaire, Bâtiment IBS-IRIS, Université d'Angers, 49033, Angers, France
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