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Han G, Song L, Ding Z, Wang Q, Yan Y, Huang J, Ma C. The Important Double-Edged Role of Astrocytes in Neurovascular Unit After Ischemic Stroke. Front Aging Neurosci 2022; 14:833431. [PMID: 35462697 PMCID: PMC9021601 DOI: 10.3389/fnagi.2022.833431] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 02/16/2022] [Indexed: 12/25/2022] Open
Abstract
In recent years, neurovascular unit (NVU) which is composed of neurons, astrocytes (Ast), microglia (MG), vascular cells and extracellular matrix (ECM), has become an attractive field in ischemic stroke. As the important component of NVU, Ast closely interacts with other constituents, which has been playing double-edged sword roles, beneficial or detrimental after ischemic stroke. Based on the pathophysiological changes, we evaluated some strategies for targeting Ast in treating ischemic stroke. The present review is focused on the roles of Ast in NVU and its complex signaling molecular network after ischemic stroke, which may be a prospective approach to the treatment of ischemic diseases in central nervous system.
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Affiliation(s)
- Guangyuan Han
- The Key Research Laboratory of Benefiting Qi for Acting Blood Circulation Method to Treat Multiple Sclerosis of State Administration of Traditional Chinese Medicine, Research Center of Neurobiology, Shanxi University of Chinese Medicine, Jinzhong, China
- Department of Neurosurgery, Sinopharm Tongmei General Hospital, Datong, China
| | - Lijuan Song
- The Key Research Laboratory of Benefiting Qi for Acting Blood Circulation Method to Treat Multiple Sclerosis of State Administration of Traditional Chinese Medicine, Research Center of Neurobiology, Shanxi University of Chinese Medicine, Jinzhong, China
- Department of Physiology, Shanxi Medical University, Taiyuan, China
- *Correspondence: Lijuan Song,
| | - Zhibin Ding
- The Key Research Laboratory of Benefiting Qi for Acting Blood Circulation Method to Treat Multiple Sclerosis of State Administration of Traditional Chinese Medicine, Research Center of Neurobiology, Shanxi University of Chinese Medicine, Jinzhong, China
- Department of Physiology, Shanxi Medical University, Taiyuan, China
| | - Qing Wang
- The Key Research Laboratory of Benefiting Qi for Acting Blood Circulation Method to Treat Multiple Sclerosis of State Administration of Traditional Chinese Medicine, Research Center of Neurobiology, Shanxi University of Chinese Medicine, Jinzhong, China
| | - Yuqing Yan
- The Key Research Laboratory of Benefiting Qi for Acting Blood Circulation Method to Treat Multiple Sclerosis of State Administration of Traditional Chinese Medicine, Research Center of Neurobiology, Shanxi University of Chinese Medicine, Jinzhong, China
- Shanxi Key Laboratory of Inflammatory Neurodegenerative Diseases, Institute of Brain Science, Shanxi Datong University, Datong, China
- Yuqing Yan,
| | - Jianjun Huang
- The Key Research Laboratory of Benefiting Qi for Acting Blood Circulation Method to Treat Multiple Sclerosis of State Administration of Traditional Chinese Medicine, Research Center of Neurobiology, Shanxi University of Chinese Medicine, Jinzhong, China
- Department of Neurosurgery, Sinopharm Tongmei General Hospital, Datong, China
- Jianjun Huang,
| | - Cungen Ma
- The Key Research Laboratory of Benefiting Qi for Acting Blood Circulation Method to Treat Multiple Sclerosis of State Administration of Traditional Chinese Medicine, Research Center of Neurobiology, Shanxi University of Chinese Medicine, Jinzhong, China
- Shanxi Key Laboratory of Inflammatory Neurodegenerative Diseases, Institute of Brain Science, Shanxi Datong University, Datong, China
- Cungen Ma,
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2
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Espírito-Santo S, Coutinho VG, Dezonne RS, Stipursky J, Dos Santos-Rodrigues A, Batista C, Paes-de-Carvalho R, Fuss B, Gomes FCA. Astrocytes as a target for Nogo-A and implications for synapse formation in vitro and in a model of acute demyelination. Glia 2021; 69:1429-1443. [PMID: 33497496 DOI: 10.1002/glia.23971] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2019] [Revised: 12/21/2020] [Accepted: 01/14/2021] [Indexed: 12/20/2022]
Abstract
Central nervous system (CNS) function depends on precise synaptogenesis, which is shaped by environmental cues and cellular interactions. Astrocytes are outstanding regulators of synapse development and plasticity through contact-dependent signals and through the release of pro- and antisynaptogenic factors. Conversely, myelin and its associated proteins, including Nogo-A, affect synapses in a inhibitory fashion and contribute to neural circuitry stabilization. However, the roles of Nogo-A-astrocyte interactions and their implications in synapse development and plasticity have not been characterized. Therefore, we aimed to investigate whether Nogo-A affects the capacity of astrocytes to induce synaptogenesis. Additionally, we assessed whether downregulation of Nogo-A signaling in an in vivo demyelination model impacts the synaptogenic potential of astrocytes. Our in vitro data show that cortical astrocytes respond to Nogo-A through RhoA pathway activation, exhibiting stress fiber formation and decreased ramified morphology. This phenotype was associated with reduced levels of GLAST protein and aspartate uptake, decreased mRNA levels of the synaptogenesis-associated genes Hevin, glypican-4, TGF-β1 and BDNF, and decreased and increased protein levels of Hevin and SPARC, respectively. Corroborating these findings, conditioned medium from Nogo-A-treated astrocytes suppressed the formation of structurally and functionally mature synapses in cortical neuronal cultures. After cuprizone-induced acute demyelination, we observed reduced immunostaining for Nogo-A in the visual cortex accompanied by higher levels of Hevin expression in astrocytes and an increase in excitatory synapse density. Hence, we suggest that interactions between Nogo-A and astrocytes might represent an important pathway of plasticity regulation and could be a target for therapeutic intervention in demyelinating diseases in the future.
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Affiliation(s)
- Sheila Espírito-Santo
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.,Departamento de Ciências Biológicas, Universidade do Estado de Minas Gerais, Minas Gerais, Brazil
| | - Vinícius G Coutinho
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Rômulo S Dezonne
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Joice Stipursky
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | | | - Carolina Batista
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Roberto Paes-de-Carvalho
- Instituto de Biologia, Programa de Neurociências, Universidade Federal Fluminense, Niterói, Brazil
| | - Babette Fuss
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Richmond, Virginia, USA
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3
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Zhao Y, Yang J, Li C, Zhou G, Wan H, Ding Z, Wan H, Zhou H. Role of the neurovascular unit in the process of cerebral ischemic injury. Pharmacol Res 2020; 160:105103. [PMID: 32739425 DOI: 10.1016/j.phrs.2020.105103] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 07/20/2020] [Accepted: 07/21/2020] [Indexed: 12/17/2022]
Abstract
Cerebral ischemic injury exhibits both high morbidity and mortality worldwide. Traditional research of the pathogenesis of cerebral ischemic injury has focused on separate analyses of the involved cell types. In recent years, the neurovascular unit (NVU) mechanism of cerebral ischemic injury has been proposed in modern medicine. Hence, more effective strategies for the treatment of cerebral ischemic injury may be provided through comprehensive analysis of brain cells and the extracellular matrix. However, recent studies that have investigated the function of the NVU in cerebral ischemic injury have been insufficient. In addition, the metabolism and energy conversion of the NVU depend on interactions among multiple cell types, which make it difficult to identify the unique contribution of each cell type. Therefore, in the present review, we comprehensively summarize the regulatory effects and recovery mechanisms of four major cell types (i.e., astrocytes, microglia, brain-microvascular endothelial cells, and neurons) in the NVU under cerebral ischemic injury, as well as discuss the interactions among these cell types in the NVU. Furthermore, we discuss the common signaling pathways and signaling factors that mediate cerebral ischemic injury in the NVU, which may help to provide a theoretical basis for the comprehensive elucidation of cerebral ischemic injury.
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Affiliation(s)
- Yu Zhao
- Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310053, PR China
| | - Jiehong Yang
- Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310053, PR China
| | - Chang Li
- Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310053, PR China
| | - Guoying Zhou
- Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310053, PR China
| | - Haofang Wan
- Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310053, PR China
| | - Zhishan Ding
- Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310053, PR China
| | - Haitong Wan
- Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310053, PR China.
| | - Huifen Zhou
- Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310053, PR China.
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4
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SOD1 Mutations Causing Familial Amyotrophic Lateral Sclerosis Induce Toxicity in Astrocytes: Evidence for Bystander Effects in a Continuum of Astrogliosis. Neurochem Res 2018; 43:166-179. [DOI: 10.1007/s11064-017-2385-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 08/11/2017] [Accepted: 08/14/2017] [Indexed: 12/18/2022]
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5
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Wilhelm CJ, Hashimoto JG, Roberts ML, Bloom SH, Andrew MR, Wiren KM. Astrocyte Dysfunction Induced by Alcohol in Females but Not Males. Brain Pathol 2015; 26:433-51. [PMID: 26088166 DOI: 10.1111/bpa.12276] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 06/10/2015] [Indexed: 01/08/2023] Open
Abstract
Chronic alcohol abuse is associated with brain damage in a sex-specific fashion, but the mechanisms involved are poorly described and remain controversial. Previous results have suggested that astrocyte gene expression is influenced by ethanol intoxication and during abstinence in vivo. Here, bioinformatic analysis of astrocyte-enriched ethanol-regulated genes in vivo revealed ubiquitin pathways as an ethanol target, but with sexually dimorphic cytokine signaling and changes associated with brain aging in females and not males. Consistent with this result, astrocyte activation was observed after exposure in female but not male animals, with reduced S100β levels in the anterior cingulate cortex and increased GFAP(+) cells in the hippocampus. In primary culture, the direct effects of chronic ethanol exposure followed by recovery on sex-specific astrocyte function were examined. Male astrocyte responses were consistent with astrocyte deactivation with reduced GFAP expression during ethanol exposure. In contrast, female astrocytes exhibited increased expression of Tnf, reduced expression of the neuroprotective cytokine Tgfb1, disrupted bioenergetics and reduced excitatory amino acid uptake following exposure or recovery. These results indicate widespread astrocyte dysfunction in ethanol-exposed females and suggest a mechanism that may underlie increased vulnerability to ethanol-induced neurotoxicity in females.
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Affiliation(s)
- Clare J Wilhelm
- VA Portland Health Care System, Portland, OR.,Department of Psychiatry, Oregon Health & Science University, Portland, OR
| | - Joel G Hashimoto
- VA Portland Health Care System, Portland, OR.,Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR
| | | | | | - Melissa R Andrew
- Cincinnati Center for Growth Disorders, Cincinnati Children's Hospital Medical Center, Cincinnati, OH
| | - Kristine M Wiren
- VA Portland Health Care System, Portland, OR.,Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR
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6
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Posada-Duque RA, Palacio-Castañeda V, Cardona-Gómez GP. CDK5 knockdown in astrocytes provide neuroprotection as a trophic source via Rac1. Mol Cell Neurosci 2015; 68:151-66. [PMID: 26160434 DOI: 10.1016/j.mcn.2015.07.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 06/24/2015] [Accepted: 07/01/2015] [Indexed: 12/17/2022] Open
Abstract
Astrocytes perform metabolic and structural support functions in the brain and contribute to the integrity of the blood-brain barrier. Astrocytes influence neuronal survival and prevent gliotoxicity by capturing glutamate (Glu), reactive oxygen species, and nutrients. During these processes, astrocytic morphological changes are supported by actin cytoskeleton remodeling and require the involvement of Rho GTPases, such as Rac1. The protein cyclin-dependent kinase 5 (CDK5) may have a dual effect on astrocytes because it has been shown to be involved in migration, senescence, and the dysfunction of glutamate recapture; however, its role in astrocytes remains unclear. Treating a possible deregulation of CDK5 with RNAi is a strategy that has been proposed as a therapy for neurodegenerative diseases. Models of glutamate gliotoxicity in the C6 astroglioma cell line, primary cultures of astrocytes, and co-cultures with neurons were used to analyze the effects of CDK5 RNAi in astrocytes and the role of Rac1 in neuronal viability. In C6 cells and primary astrocytes, CDK5 RNAi prevented the cell death generated by glutamate-induced gliotoxicity, and this finding was corroborated by pharmacological inhibition with roscovitine. This effect was associated with the appearance of lamellipodia, protrusions, increased cell area, stellation, Rac1 activation, BDNF release, and astrocytic protection in neurons that were exposed to glutamate excitotoxicity. Interestingly, Rac1 inhibition in astrocytes blocked BDNF upregulation and the astrocyte-mediated neuroprotection. Actin cytoskeleton remodeling and stellation may be a functional phenotype for BDNF release that promotes neuroprotection. In summary, our findings suggest that CDK5- knockdown in astrocytes acts as a trophic source for neuronal protection in a Rac1-dependent manner.
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Affiliation(s)
- Rafael Andrés Posada-Duque
- Neuroscience Group of Antioquia, Cellular and Molecular Neurobiology Area, Faculty of Medicine, SIU, University of Antioquia, Calle 70, No. 52-21, Medellin, Colombia
| | - Valentina Palacio-Castañeda
- Neuroscience Group of Antioquia, Cellular and Molecular Neurobiology Area, Faculty of Medicine, SIU, University of Antioquia, Calle 70, No. 52-21, Medellin, Colombia
| | - Gloria Patricia Cardona-Gómez
- Neuroscience Group of Antioquia, Cellular and Molecular Neurobiology Area, Faculty of Medicine, SIU, University of Antioquia, Calle 70, No. 52-21, Medellin, Colombia.
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7
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Mayhew J, Beart PM, Walker FR. Astrocyte and microglial control of glutamatergic signalling: a primer on understanding the disruptive role of chronic stress. J Neuroendocrinol 2015; 27:498-506. [PMID: 25737228 DOI: 10.1111/jne.12273] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2014] [Revised: 02/23/2015] [Accepted: 02/27/2015] [Indexed: 01/23/2023]
Abstract
It is now well established that chronic stress can induce significant structural remodelling of astrocytes and microglia. Until recently, however, the full significance of these morphological disturbances has remained unclear. Clues to the significance of astroglial re-organisation following stress are beginning to emerge from a compelling literature describing how astrocytes contribute to glutamatergic neurotransmission. The present review briefly summarises these two fields of research, identifies points of overlap and, in doing so, pin-points future research directions for stress neurobiology. Ultimately, understanding how chronic stress can disrupt the interactions of astrocytes and microglia with neurones has the potential in the future to improve the development of therapeutics designed to treat stress-related illnesses such as depression.
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Affiliation(s)
- J Mayhew
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW, Australia
- Centre for Translational Neuroscience and Mental Health Research, University of Newcastle, Callaghan, NSW, Australia
- Hunter Medical Research Institute, New Lambton Heights, NSW, Australia
| | - P M Beart
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Vic., Australia
| | - F R Walker
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW, Australia
- Centre for Translational Neuroscience and Mental Health Research, University of Newcastle, Callaghan, NSW, Australia
- Hunter Medical Research Institute, New Lambton Heights, NSW, Australia
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8
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O'Shea RD, Lau CL, Zulaziz N, Maclean FL, Nisbet DR, Horne MK, Beart PM. Transcriptomic analysis and 3D bioengineering of astrocytes indicate ROCK inhibition produces cytotrophic astrogliosis. Front Neurosci 2015; 9:50. [PMID: 25750613 PMCID: PMC4335181 DOI: 10.3389/fnins.2015.00050] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 02/04/2015] [Indexed: 01/07/2023] Open
Abstract
Astrocytes provide trophic, structural and metabolic support to neurons, and are considered genuine targets in regenerative neurobiology, as their phenotype arbitrates brain integrity during injury. Inhibitors of Rho kinase (ROCK) cause stellation of cultured 2D astrocytes, increased L-glutamate transport, augmented G-actin, and elevated expression of BDNF and anti-oxidant genes. Here we further explored the signposts of a cytotrophic, “healthy” phenotype by data-mining of our astrocytic transcriptome in the presence of Fasudil. Gene expression profiles of motor and autophagic cellular cascades and inflammatory/angiogenic responses were all inhibited, favoring adoption of an anti-migratory phenotype. Like ROCK inhibition, tissue engineered bioscaffolds can influence the extracellular matrix. We built upon our evidence that astrocytes maintained on 3D poly-ε-caprolactone (PCL) electrospun scaffolds adopt a cytotrophic phenotype similar to that produced by Fasudil. Using these procedures, employing mature 3D cultured astrocytes, Fasudil (100 μM) or Y27632 (30 μM) added for the last 72 h of culture altered arborization, which featured numerous additional minor processes as shown by GFAP and AHNAK immunolabelling. Both ROCK inhibitors decreased F-actin, but increased G-actin labeling, indicative of disassembly of actin stress fibers. ROCK inhibitors provide additional beneficial effects for bioengineered 3D astrocytes, including enlargement of the overall arbor. Potentially, the combined strategy of bio-compatible scaffolds with ROCK inhibition offers unique advantages for the management of glial scarring. Overall these data emphasize that manipulation of the astrocyte phenotype to achieve a “healthy biology” offers new hope for the management of inflammation in neuropathologies.
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Affiliation(s)
- Ross D O'Shea
- Department of Physiology, Anatomy and Microbiology, La Trobe University Bundoora, VIC, Australia
| | - Chew L Lau
- Florey Institute of Neuroscience and Mental Health, University of Melbourne Parkville, VIC, Australia
| | - Natasha Zulaziz
- Department of Physiology, Anatomy and Microbiology, La Trobe University Bundoora, VIC, Australia
| | - Francesca L Maclean
- Research School of Engineering, The Australian National University Canberra, ACT, Australia
| | - David R Nisbet
- Research School of Engineering, The Australian National University Canberra, ACT, Australia
| | - Malcolm K Horne
- Florey Institute of Neuroscience and Mental Health, University of Melbourne Parkville, VIC, Australia ; Department of Neurology, St. Vincent's Hospital Fitzroy, VIC, Australia
| | - Philip M Beart
- Florey Institute of Neuroscience and Mental Health, University of Melbourne Parkville, VIC, Australia
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9
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Posada-Duque RA, Barreto GE, Cardona-Gomez GP. Protection after stroke: cellular effectors of neurovascular unit integrity. Front Cell Neurosci 2014; 8:231. [PMID: 25177270 PMCID: PMC4132372 DOI: 10.3389/fncel.2014.00231] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Accepted: 07/24/2014] [Indexed: 12/16/2022] Open
Abstract
Neurological disorders are prevalent worldwide. Cerebrovascular diseases (CVDs), which account for 55% of all neurological diseases, are the leading cause of permanent disability, cognitive and motor disorders and dementia. Stroke affects the function and structure of blood-brain barrier, the loss of cerebral blood flow regulation, oxidative stress, inflammation and the loss of neural connections. Currently, no gold standard treatments are available outside the acute therapeutic window to improve outcome in stroke patients. Some promising candidate targets have been identified for the improvement of long-term recovery after stroke, such as Rho GTPases, cell adhesion proteins, kinases, and phosphatases. Previous studies by our lab indicated that Rho GTPases (Rac and RhoA) are involved in both tissue damage and survival, as these proteins are essential for the morphology and movement of neurons, astrocytes and endothelial cells, thus playing a critical role in the balance between cell survival and death. Treatment with a pharmacological inhibitor of RhoA/ROCK blocks the activation of the neurodegeneration cascade. In addition, Rac and synaptic adhesion proteins (p120 catenin and N-catenin) play critical roles in protection against cerebral infarction and in recovery by supporting the neurovascular unit and cytoskeletal remodeling activity to maintain the integrity of the brain parenchyma. Interestingly, neuroprotective agents, such as atorvastatin, and CDK5 silencing after cerebral ischemia and in a glutamate-induced excitotoxicity model may act on the same cellular effectors to recover neurovascular unit integrity. Therefore, future efforts must focus on individually targeting the structural and functional roles of each effector of neurovascular unit and the interactions in neural and non-neural cells in the post-ischemic brain and address how to promote the recovery or prevent the loss of homeostasis in the short, medium and long term.
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Affiliation(s)
- Rafael Andres Posada-Duque
- Cellular and Molecular Neurobiology Area, Group of Neuroscience of Antioquia, Faculty of Medicine, Sede de Investigación Universitaria (SIU), University of Antioquia UdeA Medellín, Colombia
| | - George E Barreto
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana Bogotá D.C., Colombia
| | - Gloria Patricia Cardona-Gomez
- Cellular and Molecular Neurobiology Area, Group of Neuroscience of Antioquia, Faculty of Medicine, Sede de Investigación Universitaria (SIU), University of Antioquia UdeA Medellín, Colombia
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10
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Lau CL, Kovacevic M, Tingleff TS, Forsythe JS, Cate HS, Merlo D, Cederfur C, Maclean FL, Parish CL, Horne MK, Nisbet DR, Beart PM. 3D Electrospun scaffolds promote a cytotrophic phenotype of cultured primary astrocytes. J Neurochem 2014; 130:215-26. [PMID: 24588462 DOI: 10.1111/jnc.12702] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 02/24/2014] [Accepted: 02/26/2014] [Indexed: 12/01/2022]
Abstract
Astrocytes are a target for regenerative neurobiology because in brain injury their phenotype arbitrates brain integrity, neuronal death and subsequent repair and reconstruction. We explored the ability of 3D scaffolds to direct astrocytes into phenotypes with the potential to support neuronal survival. Poly-ε-caprolactone scaffolds were electrospun with random and aligned fibre orientations on which murine astrocytes were sub-cultured and analysed at 4 and 12 DIV. Astrocytes survived, proliferated and migrated into scaffolds adopting 3D morphologies, mimicking in vivo stellated phenotypes. Cells on random poly-ε-caprolactone scaffolds grew as circular colonies extending processes deep within sub-micron fibres, whereas astrocytes on aligned scaffolds exhibited rectangular colonies with processes following not only the direction of fibre alignment but also penetrating the scaffold. Cell viability was maintained over 12 DIV, and cytochemistry for F-/G-actin showed fewer stress fibres on bioscaffolds relative to 2D astrocytes. Reduced cytoskeletal stress was confirmed by the decreased expression of glial fibrillary acidic protein. PCR demonstrated up-regulation of genes (excitatory amino acid transporter 2, brain-derived neurotrophic factor and anti-oxidant) reflecting healthy biologies of mature astrocytes in our extended culture protocol. This study illustrates the therapeutic potential of bioengineering strategies using 3D electrospun scaffolds which direct astrocytes into phenotypes supporting brain repair. Astrocytes exist in phenotypes with pro-survival and destructive components, and their biology can be modulated by changing phenotype. Our findings demonstrate murine astrocytes adopt a healthy phenotype when cultured in 3D. Astrocytes proliferate and extend into poly-ε-caprolactone scaffolds displaying 3D stellated morphologies with reduced GFAP expression and actin stress fibres, plus a cytotrophic gene profile. Bioengineered 3D scaffolds have potential to direct inflammation to aid regenerative neurobiology.
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Affiliation(s)
- Chew L Lau
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Australia
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11
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Sheean R, Lau C, Shin Y, O’Shea R, Beart P. Links between l-glutamate transporters, Na+/K+-ATPase and cytoskeleton in astrocytes: Evidence following inhibition with rottlerin. Neuroscience 2013; 254:335-46. [DOI: 10.1016/j.neuroscience.2013.09.043] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Revised: 09/20/2013] [Accepted: 09/21/2013] [Indexed: 02/06/2023]
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12
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D-Aspartate acts as a signaling molecule in nervous and neuroendocrine systems. Amino Acids 2012; 43:1873-86. [PMID: 22872108 DOI: 10.1007/s00726-012-1364-1] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Accepted: 07/06/2012] [Indexed: 10/28/2022]
Abstract
D-Aspartate (D-Asp) is an endogenous amino acid in the central nervous and reproductive systems of vertebrates and invertebrates. High concentrations of D-Asp are found in distinct anatomical locations, suggesting that it has specific physiological roles in animals. Many of the characteristics of D-Asp have been documented, including its tissue and cellular distribution, formation and degradation, as well as the responses elicited by D-Asp application. D-Asp performs important roles related to nervous system development and hormone regulation; in addition, it appears to act as a cell-to-cell signaling molecule. Recent studies have shown that D-Asp fulfills many, if not all, of the definitions of a classical neurotransmitter-that the molecule's biosynthesis, degradation, uptake, and release take place within the presynaptic neuron, and that it triggers a response in the postsynaptic neuron after its release. Accumulating evidence suggests that these criteria are met by a heterogeneous distribution of enzymes for D-Asp's biosynthesis and degradation, an appropriate uptake mechanism, localization within synaptic vesicles, and a postsynaptic response via an ionotropic receptor. Although D-Asp receptors remain to be characterized, the postsynaptic response of D-Asp has been studied and several L-glutamate receptors are known to respond to D-Asp. In this review, we discuss the current status of research on D-Asp in neuronal and neuroendocrine systems, and highlight results that support D-Asp's role as a signaling molecule.
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13
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Lau CL, Perreau VM, Chen MJ, Cate HS, Merlo D, Cheung NS, O'Shea RD, Beart PM. Transcriptomic profiling of astrocytes treated with the Rho kinase inhibitor fasudil reveals cytoskeletal and pro-survival responses. J Cell Physiol 2012; 227:1199-211. [PMID: 21604263 DOI: 10.1002/jcp.22838] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Inhibitors of Rho kinase (ROCK) have potential for management of neurological disorders by inhibition of glial scarring. Since astrocytes play key roles in brain physiology and pathology, we determined changes in the astrocytic transcriptome produced by the ROCK inhibitor Fasudil to obtain mechanistic insights into its beneficial action during brain injury. Cultured murine astrocytes were treated with Fasudil (100 µM) and morphological analyses revealed rapid stellation by 1 h and time-dependent (2-24 h) dissipation of F-actin-labelled stress fibres. Microarray analyses were performed on RNA and the time-course of global gene profiling (2, 6, 12 and 24 h) provided a comprehensive description of transcriptomic changes. Hierarchical clustering of differentially expressed genes and analysis for over-represented gene ontology groups using the DAVID database focused attention on Fasudil-induced changes to major biological processes regulating cellular shape and motility (actin cytoskeleton, axon guidance, transforming growth factor-β (TGFβ) signalling and tight junctions). Bioinformatic analyses of transcriptomic changes revealed how these biological processes contributed to changes in astrocytic motility and cytoskeletal reorganisation. Here genes associated with extracellular matrix were also involved, but unexpected was a subset of alterations (EAAT2, BDNF, anti-oxidant species, metabolic and signalling genes) indicative of adoption by astrocytes of a pro-survival phenotype. Expression profiles of key changes with Fasudil and another ROCK inhibitor Y27632 were validated by real-time PCR. Although effects of ROCK inhibition have been considered to be primarily cytoskeletal via reduction of glial scarring, we demonstrate additional advantageous actions likely to contribute to their ameliorative actions in brain injury.
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Affiliation(s)
- Chew L Lau
- Florey Neuroscience Institutes, University of Melbourne, Parkville, VIC, Australia
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14
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Martínez-Lozada Z, Hernández-Kelly LC, Aguilera J, López-Bayghen E, Ortega A. Signaling through EAAT-1/GLAST in cultured Bergmann glia cells. Neurochem Int 2011; 59:871-9. [DOI: 10.1016/j.neuint.2011.07.015] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Revised: 07/26/2011] [Accepted: 07/29/2011] [Indexed: 12/22/2022]
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Lau CL, O'Shea RD, Broberg BV, Bischof L, Beart PM. The Rho kinase inhibitor Fasudil up-regulates astrocytic glutamate transport subsequent to actin remodelling in murine cultured astrocytes. Br J Pharmacol 2011; 163:533-45. [PMID: 21309758 DOI: 10.1111/j.1476-5381.2011.01259.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND AND PURPOSE Glutamate transporters play a major role in maintaining brain homeostasis and the astrocytic transporters, EAAT1 and EAAT2, are functionally dominant. Astrocytic excitatory amino acid transporters (EAATs) play important roles in various neuropathologies wherein astrocytes undergo cytoskeletal changes. Astrocytic plasticity is well documented, but the interface between EAAT function, actin and the astrocytic cytoskeleton is poorly understood. Because Rho kinase (ROCK) is a key determinant of actin polymerization, we investigated the effects of ROCK inhibitors on EAAT activity and astrocytic morphology. EXPERIMENTAL APPROACH The functional activity of glutamate transport was determined in murine cultured astrocytes after exposure to the ROCK inhibitors Fasudil (HA-1077) and Y27632 using biochemical, molecular and morphological approaches. Cytochemical analyses assessed changes in astrocytic morphology, F-/G-actin, and localizations of EAAT1/2. RESULTS Fasudil and Y27632 increased [(3)H]-D-aspartate (D-Asp) uptake into astrocytes, and the action of Fasudil was time-dependent and concentration-related. The rapid stellation of astrocytes (glial fibrillary acidic protein immunocytochemistry) induced by Fasudil was accompanied by reduced phalloidin staining of F-actin and increased V(max) for [(3)H]-D-Asp uptake. Immunoblotting after biotinylation demonstrated that Fasudil increased the expression of EAAT1 and EAAT2 on the cell surface. Immunocytochemistry indicated that Fasudil induced prominent labelling of astrocytic processes by EAAT1/2. CONCLUSION AND IMPLICATIONS These data show for the first time that ROCK plays a major role in determining the cell surface expression of EAAT1/2, providing new evidence for an association between transporter function and astrocytic phenotype. ROCK inhibitors, via the actin cytoskeleton, effect a consequent elevation of glutamate transporter function - this activity profile may contribute to their beneficial actions in neuropathologies.
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Affiliation(s)
- C L Lau
- Molecular Neuropharmacology, Florey Neuroscience Institutes, Parkville, Australia
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