1
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Schneider Y, Gauer C, Andert M, Hoffmann A, Riemenschneider MJ, Krebs W, Chalmers N, Lötzsch C, Naumann UJ, Xiang W, Rothhammer V, Beckervordersandforth R, Schlachetzki JCM, Winkler J. Distinct forebrain regions define a dichotomous astrocytic profile in multiple system atrophy. Acta Neuropathol Commun 2024; 12:1. [PMID: 38167307 PMCID: PMC10759635 DOI: 10.1186/s40478-023-01699-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 11/28/2023] [Indexed: 01/05/2024] Open
Abstract
The growing recognition of a dichotomous role of astrocytes in neurodegenerative processes has heightened the need for unraveling distinct astrocytic subtypes in neurological disorders. In multiple system atrophy (MSA), a rare, rapidly progressing atypical Parkinsonian disease characterized by increased astrocyte reactivity. However the specific contribution of astrocyte subtypes to neuropathology remains elusive. Hence, we first set out to profile glial fibrillary acidic protein levels in astrocytes across the human post mortem motor cortex, putamen, and substantia nigra of MSA patients and observed an overall profound astrocytic response. Matching the post mortem human findings, a similar astrocytic phenotype was present in a transgenic MSA mouse model. Notably, MSA mice exhibited a decreased expression of the glutamate transporter 1 and glutamate aspartate transporter in the basal ganglia, but not the motor cortex. We developed an optimized astrocyte isolation protocol based on magnetic-activated cell sorting via ATPase Na+/K+ transporting subunit beta 2 and profiled the transcriptomic landscape of striatal and cortical astrocytes in transgenic MSA mice. The gene expression profile of astrocytes in the motor cortex displayed an anti-inflammatory signature with increased oligodendroglial and pro-myelinogenic expression pattern. In contrast, striatal astrocytes were defined by elevated pro-inflammatory transcripts accompanied by dysregulated genes involved in homeostatic functions for lipid and calcium metabolism. These findings provide new insights into a region-dependent, dichotomous astrocytic response-potentially beneficial in the cortex and harmful in the striatum-in MSA suggesting a differential role of astrocytes in MSA-related neurodegenerative processes.
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Affiliation(s)
- Y Schneider
- Department of Molecular Neurology, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg, Schwabachanlage 6, 91054, Erlangen, Germany
| | - C Gauer
- Department of Molecular Neurology, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg, Schwabachanlage 6, 91054, Erlangen, Germany
| | - M Andert
- Department of Molecular Neurology, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg, Schwabachanlage 6, 91054, Erlangen, Germany
| | - A Hoffmann
- Department of Molecular Neurology, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg, Schwabachanlage 6, 91054, Erlangen, Germany
- UK Dementia Research Institute, The University of Edinburgh, Edinburgh, UK
- Keenan Research Centre for Biomedical Science, St Michael's Hospital, Toronto, ON, Canada
- Department of Immunology, The University of Toronto, Toronto, ON, Canada
| | - M J Riemenschneider
- Department of Neuropathology, Regensburg University Hospital, 93053, Regensburg, Germany
| | - W Krebs
- Core Unit Bioinformatics, Data Integration and Analysis (CUBiDA), University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054, Erlangen, Germany
| | - N Chalmers
- Institute of Biochemistry, Friedrich-Alexander-University Erlangen-Nürnberg, 91054, Erlangen, Germany
| | - C Lötzsch
- Institute of Biochemistry, Friedrich-Alexander-University Erlangen-Nürnberg, 91054, Erlangen, Germany
| | - U J Naumann
- Department of Neurology, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg, 91054, Erlangen, Germany
| | - W Xiang
- Department of Molecular Neurology, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg, Schwabachanlage 6, 91054, Erlangen, Germany
| | - V Rothhammer
- Department of Neurology, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg, 91054, Erlangen, Germany
| | - R Beckervordersandforth
- Institute of Biochemistry, Friedrich-Alexander-University Erlangen-Nürnberg, 91054, Erlangen, Germany
| | - J C M Schlachetzki
- Department of Cellular and Molecular Medicine, University of California-San Diego, La Jolla, CA, 92093, USA
| | - J Winkler
- Department of Molecular Neurology, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg, Schwabachanlage 6, 91054, Erlangen, Germany.
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2
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Bedner P, Steinhäuser C. Role of Impaired Astrocyte Gap Junction Coupling in Epileptogenesis. Cells 2023; 12:1669. [PMID: 37371139 DOI: 10.3390/cells12121669] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 05/25/2023] [Accepted: 06/19/2023] [Indexed: 06/29/2023] Open
Abstract
The gap-junction-coupled astroglial network plays a central role in the regulation of neuronal activity and synchronisation, but its involvement in the pathogenesis of neuronal diseases is not yet understood. Here, we present the current state of knowledge about the impact of impaired glial coupling in the development and progression of epilepsy and discuss whether astrocytes represent alternative therapeutic targets. We focus mainly on temporal lobe epilepsy (TLE), which is the most common form of epilepsy in adults and is characterised by high therapy resistance. Functional data from TLE patients and corresponding experimental models point to a complete loss of astrocytic coupling, but preservation of the gap junction forming proteins connexin43 and connexin30 in hippocampal sclerosis. Several studies further indicate that astrocyte uncoupling is a causal event in the initiation of TLE, as it occurs very early in epileptogenesis, clearly preceding dysfunctional changes in neurons. However, more research is needed to fully understand the role of gap junction channels in epilepsy and to develop safe and effective therapeutic strategies targeting astrocytes.
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Affiliation(s)
- Peter Bedner
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Venusberg-Campus 1, 53127 Bonn, Germany
| | - Christian Steinhäuser
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Venusberg-Campus 1, 53127 Bonn, Germany
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3
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Andrioli A, Fabene PF, Mudò G, Barresi V, Di Liberto V, Frinchi M, Bentivoglio M, Condorelli DF. Downregulation of the Astroglial Connexin Expression and Neurodegeneration after Pilocarpine-Induced Status Epilepticus. Int J Mol Sci 2022; 24:ijms24010023. [PMID: 36613467 PMCID: PMC9819917 DOI: 10.3390/ijms24010023] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/12/2022] [Accepted: 12/15/2022] [Indexed: 12/24/2022] Open
Abstract
Astrocytic networks and gap junctional communication mediated by connexins (Cxs) have been repeatedly implicated in seizures, epileptogenesis, and epilepsy. However, the effect of seizures on Cx expression is controversial. The present study focused on the response of Cxs to status epilepticus (SE), which is in turn an epileptogenic insult. The expression of neuronal Cx36 and astrocytic Cx30 and Cx43 mRNAs was investigated in the brain of rats in the first day after pilocarpine-induced SE. In situ hybridization revealed a progressive decrease in Cx43 and Cx30 mRNA levels, significantly marked 24 h after SE onset in neocortical areas and the hippocampus, and in most thalamic domains, whereas Cx36 mRNA did not exhibit obvious changes. Regional evaluation with quantitative real-time-RT-PCR confirmed Cx43 and Cx30 mRNA downregulation 24 h after SE, when ongoing neuronal cell death was found in the same brain regions. Immunolabeling showed at the same time point marked a decrease in Cx43, microglia activation, and interleukin-1β induction in some microglial cells. The data showed a transient downregulation of astroglial Cxs in the cortical and thalamic areas in which SE triggers neurodegenerative events in concomitance with microglia activation and cytokine expression. This could potentially represent a protective response of neuroglial networks to SE-induced acute damage.
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Affiliation(s)
- Anna Andrioli
- Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, 37134 Verona, Italy
| | - Paolo Francesco Fabene
- Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, 37134 Verona, Italy
- Verona Unit, National Institute of Neuroscience (INN), 37129 Verona, Italy
| | - Giuseppa Mudò
- Department of Biomedicine, Neuroscience and Advanced Diagnostic (BiND), University of Palermo, 90133 Palermo, Italy
| | - Vincenza Barresi
- Unit of Medical Biochemistry, Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy
| | - Valentina Di Liberto
- Department of Biomedicine, Neuroscience and Advanced Diagnostic (BiND), University of Palermo, 90133 Palermo, Italy
| | - Monica Frinchi
- Department of Biomedicine, Neuroscience and Advanced Diagnostic (BiND), University of Palermo, 90133 Palermo, Italy
| | - Marina Bentivoglio
- Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, 37134 Verona, Italy
- Verona Unit, National Institute of Neuroscience (INN), 37129 Verona, Italy
| | - Daniele Filippo Condorelli
- Unit of Medical Biochemistry, Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy
- Correspondence:
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4
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Pacheco ALD, de Melo IS, de Araujo Costa M, Amaral MMC, de Gusmão Taveiros Silva NK, Santos YMO, Gitaí DLG, Duzzioni M, Borbely AU, Silva RS, Donatti ALF, Mestriner L, Fuzo CA, Cummings RD, Garcia-Cairasco N, Dias-Baruffi M, de Castro OW. Neuroprotective Effect of Exogenous Galectin-1 in Status Epilepticus. Mol Neurobiol 2022; 59:7354-7369. [PMID: 36171480 DOI: 10.1007/s12035-022-03038-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 09/19/2022] [Indexed: 10/14/2022]
Abstract
Intrahippocampal pilocarpine microinjection (H-PILO) induces status epilepticus (SE) that can lead to spontaneous recurrent seizures (SRS) and neurodegeneration in rodents. Studies using animal models have indicated that lectins mediate a variety of biological activities with neuronal benefits, especially galectin-1 (GAL-1), which has been identified as an effective neuroprotective compound. GAL-1 is associated with the regulation of cell adhesion, proliferation, programmed cell death, and immune responses, as well as attenuating neuroinflammation. Here, we administrated GAL-1 to Wistar rats and evaluated the severity of the SE, neurodegenerative and inflammatory patterns in the hippocampal formation. Administration of GAL-1 caused a reduction in the number of class 2 and 4 seizures, indicating a decrease in seizure severity. Furthermore, we observed a reduction in inflammation and neurodegeneration 24 h and 15 days after SE. Overall, these results suggest that GAL-1 has a neuroprotective effect in the early stage of epileptogenesis and provides new insights into the roles of exogenous lectins in temporal lobe epilepsy (TLE).
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Affiliation(s)
- Amanda Larissa Dias Pacheco
- Institute of Biological Sciences and Health, Federal University of Alagoas (UFAL), Av. Lourival de Melo Mota, km 14, Campus A. C. Simões, Cidade Universitária, Maceió, AL, CEP 57072-970, Brazil
| | - Igor Santana de Melo
- Institute of Biological Sciences and Health, Federal University of Alagoas (UFAL), Av. Lourival de Melo Mota, km 14, Campus A. C. Simões, Cidade Universitária, Maceió, AL, CEP 57072-970, Brazil
| | - Maisa de Araujo Costa
- Institute of Biological Sciences and Health, Federal University of Alagoas (UFAL), Av. Lourival de Melo Mota, km 14, Campus A. C. Simões, Cidade Universitária, Maceió, AL, CEP 57072-970, Brazil
| | - Mariah Morais Celestino Amaral
- Institute of Biological Sciences and Health, Federal University of Alagoas (UFAL), Av. Lourival de Melo Mota, km 14, Campus A. C. Simões, Cidade Universitária, Maceió, AL, CEP 57072-970, Brazil
| | - Nívea Karla de Gusmão Taveiros Silva
- Institute of Biological Sciences and Health, Federal University of Alagoas (UFAL), Av. Lourival de Melo Mota, km 14, Campus A. C. Simões, Cidade Universitária, Maceió, AL, CEP 57072-970, Brazil
| | - Yngrid Mickaelli Oliveira Santos
- Institute of Biological Sciences and Health, Federal University of Alagoas (UFAL), Av. Lourival de Melo Mota, km 14, Campus A. C. Simões, Cidade Universitária, Maceió, AL, CEP 57072-970, Brazil
| | - Daniel Leite Góes Gitaí
- Institute of Biological Sciences and Health, Federal University of Alagoas (UFAL), Av. Lourival de Melo Mota, km 14, Campus A. C. Simões, Cidade Universitária, Maceió, AL, CEP 57072-970, Brazil
| | - Marcelo Duzzioni
- Institute of Biological Sciences and Health, Federal University of Alagoas (UFAL), Av. Lourival de Melo Mota, km 14, Campus A. C. Simões, Cidade Universitária, Maceió, AL, CEP 57072-970, Brazil
| | - Alexandre Urban Borbely
- Institute of Biological Sciences and Health, Federal University of Alagoas (UFAL), Av. Lourival de Melo Mota, km 14, Campus A. C. Simões, Cidade Universitária, Maceió, AL, CEP 57072-970, Brazil
| | - Robinson Sabino Silva
- Department of Physiology, Institute of Biomedical Sciences, Federal University of Uberlândia (UFU), Uberlândia, MG, Brazil
| | - Ana Luiza Ferreira Donatti
- Department of Physiology, Medical School of Ribeirão Preto, University of São Paulo (USP), Ribeirão Preto, São Paulo, Brazil.,Department of Neuroscience and Behavioral Sciences, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Luisa Mestriner
- Department of Clinical Analyses, Toxicology, and Food Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo (USP), Ribeirão Preto, São Paulo, Brazil
| | - Carlos Alessandro Fuzo
- Department of Clinical Analyses, Toxicology, and Food Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo (USP), Ribeirão Preto, São Paulo, Brazil
| | - Richard D Cummings
- Beth Israel Deaconess Medical Center, Department of Surgery, Harvard Glycomics Center, Harvard Medical School, CLS 11087 - 3 Blackfan Circle, Boston, MA, 02115, USA
| | - Norberto Garcia-Cairasco
- Department of Physiology, Medical School of Ribeirão Preto, University of São Paulo (USP), Ribeirão Preto, São Paulo, Brazil.,Department of Neuroscience and Behavioral Sciences, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Marcelo Dias-Baruffi
- Department of Clinical Analyses, Toxicology, and Food Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo (USP), Ribeirão Preto, São Paulo, Brazil.
| | - Olagide Wagner de Castro
- Institute of Biological Sciences and Health, Federal University of Alagoas (UFAL), Av. Lourival de Melo Mota, km 14, Campus A. C. Simões, Cidade Universitária, Maceió, AL, CEP 57072-970, Brazil.
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5
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Liu YD, Tang G, Qian F, Liu L, Huang JR, Tang FR. Astroglial Connexins in Neurological and Neuropsychological Disorders and Radiation Exposure. Curr Med Chem 2021; 28:1970-1986. [PMID: 32520676 DOI: 10.2174/0929867327666200610175037] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 05/03/2020] [Accepted: 05/04/2020] [Indexed: 11/22/2022]
Abstract
Radiotherapy is a common treatment for brain and spinal cord tumors and also a risk factor for neuropathological changes in the brain leading to different neurological and neuropsychological disorders. Astroglial connexins are involved in brain inflammation, development of Alzheimer's Disease (AD), depressive, epilepsy, and amyotrophic lateral sclerosis, and are affected by radiation exposure. Therefore, it is speculated that radiation-induced changes of astroglial connexins may be related to the brain neuropathology and development of neurological and neuropsychological disorders. In this paper, we review the functional expression and regulation of astroglial connexins expressed between astrocytes and different types of brain cells (including oligodendrocytes, microglia, neurons and endothelial cells). The roles of these connexins in the development of AD, depressive, epilepsy, amyotrophic lateral sclerosis and brain inflammation have also been summarized. The radiation-induced astroglial connexins changes and development of different neurological and neuropsychological disorders are then discussed. Based on currently available data, we propose that radiation-induced astroglial connexins changes may be involved in the genesis of different neurological and neuropsychological disorders which depends on the age, brain regions, and radiation doses/dose rates. The abnormal astroglial connexins may be novel therapeutic targets for the prevention of radiation-induced cognitive impairment, neurological and neuropsychological disorders.
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Affiliation(s)
- Yuan Duo Liu
- Medical School of Yangtze University, Jingzhou 434000, China
| | - Ge Tang
- Woodlands Health Campus, National Healthcare Group Singapore, Singapore
| | - Feng Qian
- Medical School of Yangtze University, Jingzhou 434000, China
| | - Lian Liu
- Medical School of Yangtze University, Jingzhou 434000, China
| | | | - Feng Ru Tang
- Radiation Physiology Laboratory, Singapore Nuclear Research and Safety Initiative, National University of Singapore, Singapore
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6
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Synaptic Reshaping and Neuronal Outcomes in the Temporal Lobe Epilepsy. Int J Mol Sci 2021; 22:ijms22083860. [PMID: 33917911 PMCID: PMC8068229 DOI: 10.3390/ijms22083860] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 04/02/2021] [Accepted: 04/04/2021] [Indexed: 12/11/2022] Open
Abstract
Temporal lobe epilepsy (TLE) is one of the most common types of focal epilepsy, characterized by recurrent spontaneous seizures originating in the temporal lobe(s), with mesial TLE (mTLE) as the worst form of TLE, often associated with hippocampal sclerosis. Abnormal epileptiform discharges are the result, among others, of altered cell-to-cell communication in both chemical and electrical transmissions. Current knowledge about the neurobiology of TLE in human patients emerges from pathological studies of biopsy specimens isolated from the epileptogenic zone or, in a few more recent investigations, from living subjects using positron emission tomography (PET). To overcome limitations related to the use of human tissue, animal models are of great help as they allow the selection of homogeneous samples still presenting a more various scenario of the epileptic syndrome, the presence of a comparable control group, and the availability of a greater amount of tissue for in vitro/ex vivo investigations. This review provides an overview of the structural and functional alterations of synaptic connections in the brain of TLE/mTLE patients and animal models.
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7
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Yang TT, Qian F, Liu L, Peng XC, Huang JR, Ren BX, Tang FR. Astroglial connexins in epileptogenesis. Seizure 2020; 84:122-128. [PMID: 33348235 DOI: 10.1016/j.seizure.2020.11.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 11/27/2020] [Accepted: 11/29/2020] [Indexed: 12/27/2022] Open
Abstract
The astroglial network connected through gap junctions assembling from connexins physiologically balances the concentrations of ions and neurotransmitters around neurons. Astrocytic dysfunction has been associated with many neurological disorders including epilepsy. Dissociated gap junctions result in the increased activity of connexin hemichannels which triggers brain pathophysiological changes. Previous studies in patients and animal models of epilepsy indicate that the reduced gap junction coupling from assembled connexin hemichannels in the astrocytes may play an important role in epileptogenesis. This abnormal cell-to-cell communication is now emerging as an important feature of brain pathologies and being considered as a novel therapeutic target for controlling epileptogenesis. In particular, candidate drugs with ability of inhibition of connexin hemichannel activity and enhancement of gap junction formation in astrocytes should be explored to prevent epileptogenesis and control epilepsy.
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Affiliation(s)
- Ting-Ting Yang
- School of Basic Medicine, Health Science Center, Yangtze University, Jingzhou, Hubei Province, 434023, China
| | - Feng Qian
- School of Basic Medicine, Health Science Center, Yangtze University, Jingzhou, Hubei Province, 434023, China.
| | - Lian Liu
- School of Basic Medicine, Health Science Center, Yangtze University, Jingzhou, Hubei Province, 434023, China
| | - Xiao-Chun Peng
- School of Basic Medicine, Health Science Center, Yangtze University, Jingzhou, Hubei Province, 434023, China
| | - Jiang-Rong Huang
- School of Basic Medicine, Health Science Center, Yangtze University, Jingzhou, Hubei Province, 434023, China
| | - Bo-Xu Ren
- School of Basic Medicine, Health Science Center, Yangtze University, Jingzhou, Hubei Province, 434023, China
| | - Feng-Ru Tang
- Radiobiology Research Laboratory, Singapore Nuclear Research and Safety Initiative, National University of Singapore, Singapore.
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8
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Lapato AS, Thompson SM, Parra K, Tiwari-Woodruff SK. Astrocyte Glutamate Uptake and Water Homeostasis Are Dysregulated in the Hippocampus of Multiple Sclerosis Patients With Seizures. ASN Neuro 2020; 12:1759091420979604. [PMID: 33297722 PMCID: PMC7734542 DOI: 10.1177/1759091420979604] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
While seizure disorders are more prevalent among multiple sclerosis (MS) patients than the population overall and prognosticate earlier death & disability, their etiology remains unclear. Translational data indicate perturbed expression of astrocytic molecules contributing to homeostatic neuronal excitability, including water channels (AQP4) and synaptic glutamate transporters (EAAT2), in a mouse model of MS with seizures (MS+S). However, astrocytes in MS+S have not been examined. To assess the translational relevance of astrocyte dysfunction observed in a mouse model of MS+S, demyelinated lesion burden, astrogliosis, and astrocytic biomarkers (AQP4/EAAT2/ connexin-CX43) were evaluated by immunohistochemistry in postmortem hippocampi from MS & MS+S donors. Lesion burden was comparable in MS & MS+S cohorts, but astrogliosis was elevated in MS+S CA1 with a concomitant decrease in EAAT2 signal intensity. AQP4 signal declined in MS+S CA1 & CA3 with a loss of perivascular AQP4 in CA1. CX43 expression was increased in CA3. Together, these data suggest that hippocampal astrocytes from MS+S patients display regional differences in expression of molecules associated with glutamate buffering and water homeostasis that could exacerbate neuronal hyperexcitability. Importantly, mislocalization of CA1 perivascular AQP4 seen in MS+S is analogous to epileptic hippocampi without a history of MS, suggesting convergent pathophysiology. Furthermore, as neuropathology was concentrated in MS+S CA1, future study is warranted to determine the pathophysiology driving regional differences in glial function in the context of seizures during demyelinating disease.
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Affiliation(s)
- Andrew S Lapato
- Division of Biomedical Sciences, UCR School of Medicine, Riverside, California, United States.,Center for Glial-Neuronal Interaction, UCR School of Medicine, Riverside, California, United States
| | - Sarah M Thompson
- Division of Biomedical Sciences, UCR School of Medicine, Riverside, California, United States
| | - Karen Parra
- Division of Biomedical Sciences, UCR School of Medicine, Riverside, California, United States
| | - Seema K Tiwari-Woodruff
- Division of Biomedical Sciences, UCR School of Medicine, Riverside, California, United States.,Center for Glial-Neuronal Interaction, UCR School of Medicine, Riverside, California, United States.,Department of Neuroscience, UCR School of Medicine, Riverside, California, United States
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9
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Astrocytic Connexin43 Channels as Candidate Targets in Epilepsy Treatment. Biomolecules 2020; 10:biom10111578. [PMID: 33233647 PMCID: PMC7699773 DOI: 10.3390/biom10111578] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 11/17/2020] [Accepted: 11/18/2020] [Indexed: 12/15/2022] Open
Abstract
In epilepsy research, emphasis is put on exploring non-neuronal targets such as astrocytic proteins, since many patients remain pharmacoresistant to current treatments, which almost all target neuronal mechanisms. This paper reviews available data on astrocytic connexin43 (Cx43) signaling in seizures and epilepsy. Cx43 is a widely expressed transmembrane protein and the constituent of gap junctions (GJs) and hemichannels (HCs), allowing intercellular and extracellular communication, respectively. A plethora of research papers show altered Cx43 mRNA levels, protein expression, phosphorylation state, distribution and/or functional coupling in human epileptic tissue and experimental models. Human Cx43 mutations are linked to seizures as well, as 30% of patients with oculodentodigital dysplasia (ODDD), a rare genetic condition caused by mutations in the GJA1 gene coding for Cx43 protein, exhibit neurological symptoms including seizures. Cx30/Cx43 double knock-out mice show increased susceptibility to evoked epileptiform events in brain slices due to impaired GJ-mediated redistribution of K+ and glutamate and display a higher frequency of spontaneous generalized chronic seizures in an epilepsy model. Contradictory, Cx30/Cx43 GJs can traffic nutrients to high-energy demanding neurons and initiate astrocytic Ca2+ waves and hyper synchronization, thereby supporting proconvulsant effects. The general connexin channel blocker carbenoxolone and blockers from the fenamate family diminish epileptiform activity in vitro and improve seizure outcome in vivo. In addition, interventions with more selective peptide inhibitors of HCs display anticonvulsant actions. To conclude, further studies aiming to disentangle distinct roles of HCs and GJs are necessary and tools specifically targeting Cx43 HCs may facilitate the search for novel epilepsy treatments.
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10
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Zancan M, Malysz T, Moura DJ, Morás AM, Steffens L, Rasia-Filho AA. Gap junctions and expression of Cx36, Cx43 and Cx45 in the posterodorsal medial amygdala of adult rats. Histol Histopathol 2020; 35:395-403. [PMID: 31495909 DOI: 10.14670/hh-18-160] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The posterodorsal medial amygdala (MePD) has an adapted synaptic organization that dynamically modulates reproduction and other social behaviors in rats. Discrete gap junctions between glial cells were previously reported in the MePD neuropil. Connexins (Cx) are components of gap junctions and indicative of cellular electrical coupling. Here, we report the ultrastructural occurrence of gap junctions between neurons in the MePD and demonstrate the expression and immunofluorescent labeling of Cx36, Cx43 and Cx45 in this subcortical area of adult male rats. Few neuronal gap junctions were found in the MePD and, when identified, occurred between dendrites. On the other hand, there is a diffuse presence and distribution of punctate labelling for the tested Cxs. Puncta were visualized isolated or forming clusters in the same focal plane of cell bodies or along the MePD neuropil. The Cx36 puncta were found in neurons, Cx43 in astrocytes and Cx45 in both neurons and astrocytes. Our data indicate the presence of few gap junctions and different Cxs composition in the MePD. Because Cxs can assemble, form hemichannel units and/or serve as transcriptional regulator, it is likely that additional modulation of intercellular communication can occur besides the chemical transmission in the MePD of adult rats.
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Affiliation(s)
- Mariana Zancan
- Universidade Federal de Ciências da Saúde de Porto Alegre/DCBS-Physiology, Porto Alegre-RS, Brazil
| | - Taís Malysz
- Universidade Federal do Rio Grande do Sul/ICBS-Anatomy, Porto Alegre-RS, Brazil
- Universidade Federal do Rio Grande do Sul/Graduate Program in Neurosciences, Porto Alegre-RS, Brazil
| | - Dinara J Moura
- Universidade Federal de Ciências da Saúde de Porto Alegre/Graduate Program in Biosciences, Porto Alegre-RS, Brazil
| | - Ana Moira Morás
- Universidade Federal de Ciências da Saúde de Porto Alegre/Graduate Program in Biosciences, Porto Alegre-RS, Brazil
| | - Luiza Steffens
- Universidade Federal de Ciências da Saúde de Porto Alegre/Graduate Program in Biosciences, Porto Alegre-RS, Brazil
| | - Alberto A Rasia-Filho
- Universidade Federal do Rio Grande do Sul/Graduate Program in Neurosciences, Porto Alegre-RS, Brazil
- Universidade Federal de Ciências da Saúde de Porto Alegre/Graduate Program in Biosciences, Porto Alegre-RS, Brazil
- Universidade Federal de Ciências da Saúde de Porto Alegre/DCBS-Physiology, Porto Alegre-RS, Brazil.
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Lagos-Cabré R, Burgos-Bravo F, Avalos AM, Leyton L. Connexins in Astrocyte Migration. Front Pharmacol 2020; 10:1546. [PMID: 32009957 PMCID: PMC6974553 DOI: 10.3389/fphar.2019.01546] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 11/29/2019] [Indexed: 12/18/2022] Open
Abstract
Astrocytes have long been considered the supportive cells of the central nervous system, but during the last decades, they have gained much more attention because of their active participation in the modulation of neuronal function. For example, after brain damage, astrocytes become reactive and undergo characteristic morphological and molecular changes, such as hypertrophy and increase in the expression of glial fibrillary acidic protein (GFAP), in a process known as astrogliosis. After severe damage, astrocytes migrate to the lesion site and proliferate, which leads to the formation of a glial scar. At this scar-forming stage, astrocytes secrete many factors, such as extracellular matrix proteins, cytokines, growth factors and chondroitin sulfate proteoglycans, stop migrating, and the process is irreversible. Although reactive gliosis is a normal physiological response that can protect brain cells from further damage, it also has detrimental effects on neuronal survival, by creating a hostile and non-permissive environment for axonal repair. The transformation of astrocytes from reactive to scar-forming astrocytes highlights migration as a relevant regulator of glial scar formation, and further emphasizes the importance of efficient communication between astrocytes in order to orchestrate cell migration. The coordination between astrocytes occurs mainly through Connexin (Cx) channels, in the form of direct cell-cell contact (gap junctions, GJs) or contact between the extracellular matrix and the astrocytes (hemichannels, HCs). Reactive astrocytes increase the expression levels of several proteins involved in astrocyte migration, such as αvβ3 Integrin, Syndecan-4 proteoglycan, the purinergic receptor P2X7, Pannexin1, and Cx43 HCs. Evidence has indicated that Cx43 HCs play a role in regulating astrocyte migration through the release of small molecules to the extracellular space, which then activate receptors in the same or adjacent cells to continue the signaling cascades required for astrocyte migration. In this review, we describe the communication of astrocytes through Cxs, the role of Cxs in inflammation and astrocyte migration, and discuss the molecular mechanisms that regulate Cx43 HCs, which may provide a therapeutic window of opportunity to control astrogliosis and the progression of neurodegenerative diseases.
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Affiliation(s)
- Raúl Lagos-Cabré
- Cellular Communication Laboratory, Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Advanced Center for Chronic Diseases (ACCDiS), Center for Studies on Exercise, Metabolism and Cancer (CEMC), Facultad de Medicina, Instituto de Ciencias Biomédicas (ICBM), Universidad de Chile, Santiago, Chile
| | - Francesca Burgos-Bravo
- Cellular Communication Laboratory, Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Advanced Center for Chronic Diseases (ACCDiS), Center for Studies on Exercise, Metabolism and Cancer (CEMC), Facultad de Medicina, Instituto de Ciencias Biomédicas (ICBM), Universidad de Chile, Santiago, Chile
| | - Ana María Avalos
- Facultad de Ciencias de la Salud, Instituto de Ciencias Biomédicas, Universidad Autónoma de Chile, Santiago, Chile
| | - Lisette Leyton
- Cellular Communication Laboratory, Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Advanced Center for Chronic Diseases (ACCDiS), Center for Studies on Exercise, Metabolism and Cancer (CEMC), Facultad de Medicina, Instituto de Ciencias Biomédicas (ICBM), Universidad de Chile, Santiago, Chile
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12
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Proliferation of NG2 cells in the epileptic hippocampus. Epilepsy Res 2019; 152:67-72. [PMID: 30909054 DOI: 10.1016/j.eplepsyres.2019.03.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Revised: 02/25/2019] [Accepted: 03/09/2019] [Indexed: 12/20/2022]
Abstract
NG2 cells are oligodendrocyte progenitor cells, and have been shown to receive synaptic input from pyramidal neurons to generate action potentials. Whether any change of these cells occurs after status epilepticus (SE) and subsequent temporal lobe epilepsy remains unknown. In the present study, the expression of NG2 was investigated in the mouse hippocampus after pilocarpine-induced status epilepticus (PISE). We showed that reactive NG2 cells were significantly increased from 1 day to 2 months after PISE. Double immunofluorescence indicated that few NG2 cells differentiated into neurons and astrocytes after PISE, whereas the number of NG2 cells was increased significantly in the stratum lucidum of CA3 area from 1 day onwards after PISE. Our results suggest that the significantly increased reactive NG2 cells from acute to chronic stage after PISE may be involved in epileptogenesis.
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Vargas-Sánchez K, Mogilevskaya M, Rodríguez-Pérez J, Rubiano MG, Javela JJ, González-Reyes RE. Astroglial role in the pathophysiology of status epilepticus: an overview. Oncotarget 2018; 9:26954-26976. [PMID: 29928494 PMCID: PMC6003549 DOI: 10.18632/oncotarget.25485] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Accepted: 05/09/2018] [Indexed: 12/11/2022] Open
Abstract
Status epilepticus is a medical emergency with elevated morbidity and mortality rates, and represents a leading cause of epilepsy-related deaths. Though status epilepticus can occur at any age, it manifests more likely in children and elderly people. Despite the common prevalence of epileptic disorders, a complete explanation for the mechanisms leading to development of self-limited or long lasting seizures (as in status epilepticus) are still lacking. Apart from neurons, research evidence suggests the involvement of immune and glial cells in epileptogenesis. Among glial cells, astrocytes represent an ideal target for the study of the pathophysiology of status epilepticus, due to their key role in homeostatic balance of the central nervous system. During status epilepticus, astroglial cells are activated by the presence of cytokines, damage associated molecular patterns and reactive oxygen species. The persistent activation of astrocytes leads to a decrease in glutamate clearance with a corresponding accumulation in the synaptic extracellular space, increasing the chance of neuronal excitotoxicity. Moreover, major alterations in astrocytic gap junction coupling, inflammation and receptor expression, facilitate the generation of seizures. Astrocytes are also involved in dysregulation of inhibitory transmission in the central nervous system and directly participate in ionic homeostatic alterations during status epilepticus. In the present review, we focus on the functional and structural changes in astrocytic activity that participate in the development and maintenance of status epilepticus, with special attention on concurrent inflammatory alterations. We also include potential astrocytic treatment targets for status epilepticus.
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Affiliation(s)
- Karina Vargas-Sánchez
- Biomedical Sciences Research Group, School of Medicine, Universidad Antonio Nariño, Bogotá, Colombia
| | | | - John Rodríguez-Pérez
- Biomedical Sciences Research Group, School of Medicine, Universidad Antonio Nariño, Bogotá, Colombia
| | - María G Rubiano
- Biomedical Sciences Research Group, School of Medicine, Universidad Antonio Nariño, Bogotá, Colombia
| | - José J Javela
- Grupo de Clínica y Salud Mental, Programa de Psicología, Universidad Católica de Pereira, Pereira, Colombia
| | - Rodrigo E González-Reyes
- Universidad del Rosario, Escuela de Medicina y Ciencias de la Salud, GI en Neurociencias-NeURos, Bogotá, Colombia
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Wu XL, Ma DM, Zhang W, Zhou JS, Huo YW, Lu M, Tang FR. Cx36 in the mouse hippocampus during and after pilocarpine-induced status epilepticus. Epilepsy Res 2018; 141:64-72. [PMID: 29476948 DOI: 10.1016/j.eplepsyres.2018.02.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 01/24/2018] [Accepted: 02/13/2018] [Indexed: 12/24/2022]
Abstract
Gap junctions play an important role in the synchronization activity of coupled cells. Hippocampal inhibitory interneurons are involved in epileptogenesis and seizure activity, and express gap junction protein connexin (Cx) 36. Cx36 is also localized in the axons (mossy fibers) of granule cells in the dentate gyrus. While it has been documented that Cx36 is involved in epileptogenesis, there are still controversies regarding the expression levels of Cx36 at different developmental stages of human and animal models of epileptogenesis. In this study, the expression of Cx36 was investigated in the mouse hippocampus at 1 h, 4 h during pilocarpine-induced status epilepticus (PISE) and 1 week, 2 months after PISE. We found that Cx36 was down-regulated in neurons at different time points during and after PISE, whereas it was increased significantly in the stratum lucidum of CA3 area at 2 months after PISE. Double immunofluorescence indicated that Cx36 was localized in parvalbumin (PV) immunopositive interneuron in CA1 area and in mossy fibers and their terminals in the stratum lucidum of CA3 area. It suggests that decreased expression of Cx36 in interneurons may be related to less effective inhibitory control of excitatory activity of hippocampal principal neurons. However, the increased Cx36 immunopositive product in mossy fibers at the chronic stage after PISE may enhance the contacts between granule cells in the dentate gyrus and pyramidal neurons in CA3 area. The two different changes of Cx36 may be implicated in the epileptogenesis.
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Affiliation(s)
- X L Wu
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education of China, Xi'an, Shaanxi 710061, China
| | - D M Ma
- Department of Thoracic Surgery, The Ninth Affiliated Hospital of Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710054, China
| | - W Zhang
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education of China, Xi'an, Shaanxi 710061, China
| | - J S Zhou
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education of China, Xi'an, Shaanxi 710061, China
| | - Y W Huo
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education of China, Xi'an, Shaanxi 710061, China
| | - M Lu
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education of China, Xi'an, Shaanxi 710061, China
| | - F R Tang
- Radiation Physiology Laboratory, Singapore Nuclear Research and Safety Initiative (SNRSI), National University of Singapore, 1 CREATE Way #04-01, CREATE Tower 138602, Singapore.
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Motaghi S, Sayyah M, Babapour V, Mahdian R. Hippocampal Expression of Connexin36 and Connexin43 during Epileptogenesis in Pilocarpine Model of Epilepsy. IRANIAN BIOMEDICAL JOURNAL 2017; 21:167-73. [PMID: 28042145 PMCID: PMC5392219 DOI: 10.18869/acadpub.ibj.21.3.167] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2016] [Revised: 04/16/2016] [Accepted: 04/20/2016] [Indexed: 02/06/2023]
Abstract
BACKGROUND Gap junctions (GJs) provide direct intercellular communications that are formed by hexameric protein subunits, called connexin (Cx). The role of Cxs in epileptogenesis has not received sufficient attention. Hippocampus with critical function in epileptogenesis has a wide network of GJs. We examined the protein expression levels of hippocampal Cx36 (the prominent Cx present between GABAergic interneurons) and Cx43 (the main Cx expressed by astrocytes) during epileptogenesis in the pilocarpine model of epilepsy. METHODS Male Wistar rats received scopolamine (1 mg/kg, s.c.). Pilocarpine (380 mg/kg, i.p.) was administered 30 min thereafter to induce status epilepticus (SE). SE was stopped 2 h later by diazepam (10 mg/kg, i.p.). Cx36 and Cx43 protein expression was assessed by Western blot analysis in the hippocampus of SE-experienced rats, after injection of diazepam (F0 subgroup), after acquisition of focal seizures (F3 subgroup), and after development of generalized seizures (F5 subgroup). The control subgroups, C0, C3, and C5, were aged-matched rats, which received saline (1 ml/kg, i.p.) instead of pilocarpine. Injection of scopolamine and diazepam, and dissection of hippocampi were carried out at the same time interval as the test subgroups. RESULTS SE emerged in 67.1% of pilocarpine-treated animals. Focal and generalized seizures developed 3.8±0.4 and 7.0±0.5 days after SE, respectively. Cx36 protein abundance was not significantly different between test and control groups in the three time points. However, Cx43 protein level showed 40% increase in F3 subgroup (P<0.05 compared to C3, P<0.01 compared to F0 and F5). CONCLUSION Hippocampal Cx43 is overexpressed in pilocarpine model of epileptogenesis after acquisition of focal seizures.
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Affiliation(s)
- Sahel Motaghi
- Department of Physiology and Pharmacology, Pasteur Institute of Iran, Tehran, Iran
- Department of Basic Sciences, Faculty of Veterinary Medicine, Shahid Bahonar University of Kerman, Kerman, Iran
- Department of Physiology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
| | - Mohammad Sayyah
- Department of Physiology and Pharmacology, Pasteur Institute of Iran, Tehran, Iran
| | - Vahab Babapour
- Department of Physiology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
| | - Reza Mahdian
- Department of Molecular Medicine, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
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Manjarrez-Marmolejo J, Franco-Pérez J. Gap Junction Blockers: An Overview of their Effects on Induced Seizures in Animal Models. Curr Neuropharmacol 2017; 14:759-71. [PMID: 27262601 PMCID: PMC5050393 DOI: 10.2174/1570159x14666160603115942] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 02/26/2016] [Accepted: 04/21/2016] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Gap junctions are clusters of intercellular channels allowing the bidirectional pass of ions directly into the cytoplasm of adjacent cells. Electrical coupling mediated by gap junctions plays a role in the generation of highly synchronized electrical activity. The hypersynchronous neuronal activity is a distinctive characteristic of convulsive events. Therefore, it has been postulated that enhanced gap junctional communication is an underlying mechanism involved in the generation and maintenance of seizures. There are some chemical compounds characterized as gap junction blockers because of their ability to disrupt the gap junctional intercellular communication. OBJECTIVE Hence, the aim of this review is to analyze the available data concerning the effects of gap junction blockers specifically in seizure models. RESULTS Carbenoxolone, quinine, mefloquine, quinidine, anandamide, oleamide, heptanol, octanol, meclofenamic acid, niflumic acid, flufenamic acid, glycyrrhetinic acid and retinoic acid have all been evaluated on animal seizure models. In vitro, these compounds share anticonvulsant effects typically characterized by the reduction of both amplitude and frequency of the epileptiform activity induced in brain slices. In vivo, gap junction blockers modify the behavioral parameters related to seizures induced by 4-aminopyridine, pentylenetetrazole, pilocarpine, penicillin and maximal electroshock. CONCLUSION Although more studies are still required, these molecules could be a promising avenue in the search for new pharmaceutical alternatives for the treatment of epilepsy.
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Affiliation(s)
| | - Javier Franco-Pérez
- Laboratory of Physiology of Reticular Formation, National Institute of Neurology and Neurosurgery, M.V.S. Insurgentes Sur 3877, Col. La Fama, C.P. 14269, Mexico D.F., Mexico
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