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Colón Ortiz C, Eroglu C. Astrocyte signaling and interactions in Multiple Sclerosis. Curr Opin Cell Biol 2024; 86:102307. [PMID: 38145604 PMCID: PMC10922437 DOI: 10.1016/j.ceb.2023.102307] [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: 09/18/2023] [Revised: 11/22/2023] [Accepted: 12/06/2023] [Indexed: 12/27/2023]
Abstract
Multiple Sclerosis (MS) is a common cause of impairment in working-aged adults. MS is characterized by neuroinflammation and infiltration of peripheral immune cells to the brain, which cause myelin loss and death of oligodendrocytes and neurons. Many studies on MS have focused on the peripheral immune sources of demyelination and repair. However, recent studies revealed that a glial cell type, the astrocytes, undergo robust morphological and transcriptomic changes that contribute significantly to demyelination and myelin repair. Here, we discuss recent findings elucidating signaling modalities that astrocytes acquire or lose in MS and how these changes alter the interactions of astrocytes with other nervous system cell types.
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Affiliation(s)
- Crystal Colón Ortiz
- Department of Cell Biology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Cagla Eroglu
- Department of Cell Biology, Duke University Medical Center, Durham, NC, 27710, USA; Department of Neurobiology, Duke University Medical Center, Durham, NC, 27710, USA; Howard Hughes Medical Institute, Duke University, Durham, NC, 27710, USA.
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Kipp M. Astrocytes: Lessons Learned from the Cuprizone Model. Int J Mol Sci 2023; 24:16420. [PMID: 38003609 PMCID: PMC10671869 DOI: 10.3390/ijms242216420] [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: 10/12/2023] [Revised: 11/06/2023] [Accepted: 11/14/2023] [Indexed: 11/26/2023] Open
Abstract
A diverse array of neurological and psychiatric disorders, including multiple sclerosis, Alzheimer's disease, and schizophrenia, exhibit distinct myelin abnormalities at both the molecular and histological levels. These aberrations are closely linked to dysfunction of oligodendrocytes and alterations in myelin structure, which may be pivotal factors contributing to the disconnection of brain regions and the resulting characteristic clinical impairments observed in these conditions. Astrocytes, which significantly outnumber neurons in the central nervous system by a five-to-one ratio, play indispensable roles in the development, maintenance, and overall well-being of neurons and oligodendrocytes. Consequently, they emerge as potential key players in the onset and progression of a myriad of neurological and psychiatric disorders. Furthermore, targeting astrocytes represents a promising avenue for therapeutic intervention in such disorders. To gain deeper insights into the functions of astrocytes in the context of myelin-related disorders, it is imperative to employ appropriate in vivo models that faithfully recapitulate specific aspects of complex human diseases in a reliable and reproducible manner. One such model is the cuprizone model, wherein metabolic dysfunction in oligodendrocytes initiates an early response involving microglia and astrocyte activation, culminating in multifocal demyelination. Remarkably, following the cessation of cuprizone intoxication, a spontaneous process of endogenous remyelination occurs. In this review article, we provide a historical overview of studies investigating the responses and putative functions of astrocytes in the cuprizone model. Following that, we list previously published works that illuminate various aspects of the biology and function of astrocytes in this multiple sclerosis model. Some of the studies are discussed in more detail in the context of astrocyte biology and pathology. Our objective is twofold: to provide an invaluable overview of this burgeoning field, and, more importantly, to inspire fellow researchers to embark on experimental investigations to elucidate the multifaceted functions of this pivotal glial cell subpopulation.
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Affiliation(s)
- Markus Kipp
- Institute of Anatomy, Rostock University Medical Center, 18057 Rostock, Germany
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Coutinho Costa VG, Araújo SES, Alves-Leon SV, Gomes FCA. Central nervous system demyelinating diseases: glial cells at the hub of pathology. Front Immunol 2023; 14:1135540. [PMID: 37261349 PMCID: PMC10227605 DOI: 10.3389/fimmu.2023.1135540] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2023] [Accepted: 04/28/2023] [Indexed: 06/02/2023] Open
Abstract
Inflammatory demyelinating diseases (IDDs) are among the main causes of inflammatory and neurodegenerative injury of the central nervous system (CNS) in young adult patients. Of these, multiple sclerosis (MS) is the most frequent and studied, as it affects about a million people in the USA alone. The understanding of the mechanisms underlying their pathology has been advancing, although there are still no highly effective disease-modifying treatments for the progressive symptoms and disability in the late stages of disease. Among these mechanisms, the action of glial cells upon lesion and regeneration has become a prominent research topic, helped not only by the discovery of glia as targets of autoantibodies, but also by their role on CNS homeostasis and neuroinflammation. In the present article, we discuss the participation of glial cells in IDDs, as well as their association with demyelination and synaptic dysfunction throughout the course of the disease and in experimental models, with a focus on MS phenotypes. Further, we discuss the involvement of microglia and astrocytes in lesion formation and organization, remyelination, synaptic induction and pruning through different signaling pathways. We argue that evidence of the several glia-mediated mechanisms in the course of CNS demyelinating diseases supports glial cells as viable targets for therapy development.
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Affiliation(s)
| | - Sheila Espírito-Santo Araújo
- Laboratório de Biologia Celular e Tecidual, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, Brazil
| | - Soniza Vieira Alves-Leon
- Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
- Instituto Biomédico, Universidade Federal do Estado do Rio de Janeiro, Rio de Janeiro, Brazil
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Khaspekov LG, Frumkina LE. Molecular Mechanisms of Astrocyte Involvement in Synaptogenesis and Brain Synaptic Plasticity. BIOCHEMISTRY. BIOKHIMIIA 2023; 88:502-514. [PMID: 37080936 DOI: 10.1134/s0006297923040065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/22/2023]
Abstract
Astrocytes perform a wide range of important functions in the brain. As structural and functional components of synapses, astrocytes secrete various factors (proteins, lipids, small molecules, etc.) that bind to neuronal receptor and contribute to synaptogenesis and regulation of synaptic contacts. Astrocytic factors play a key role in the formation of neural networks undergoing short- and long-term synaptic morphological and functional rearrangements essential in the memory formation and behavior. The review summarizes the data on the molecular mechanisms mediating the involvement of astrocyte-secreted factors in synaptogenesis in the brain and provides up-to-date information on the role of astrocytes and astrocytic synaptogenic factors in the long-term plastic rearrangements of synaptic contacts.
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Dos Santos Heringer L, Rios Carvalho J, Teixeira Oliveira J, Texeira Silva B, de Souza Aguiar Dos Santos DM, Martinez Martinez Toledo AL, Borges Savoldi LM, Magalhães Portela D, Adriani Marques S, Campello Costa Lopes P, Blanco Martinez AM, Mendonça HR. Altered excitatory and inhibitory neocortical circuitry leads to increased convulsive severity after pentylenetetrazol injection in an animal model of schizencephaly, but not of microgyria. Epilepsia Open 2022; 7:462-473. [PMID: 35808864 PMCID: PMC9436300 DOI: 10.1002/epi4.12625] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 06/30/2022] [Indexed: 11/10/2022] Open
Abstract
OBJECTIVE Malformations of the polymicrogyria spectrum can be mimicked in rodents through neonatal transcranial focal cortical freeze lesions. The animals presenting the malformations present both altered synaptic events and epileptiform activity in the vicinity of the microgyrus, but the comprehension of their contribution to increased predisposition or severity of seizures require further studies. METHODS In order to investigate these issues, we induced both microgyria and schizencephaly in 57 mice and evaluated: their convulsive susceptibility and severity after pentyleneterazol (PTZ) treatment, the quantification of their symmetric and asymmetric synapses, the morphology of their dendritic arbors, and the content of modulators of synaptogenesis, such as SPARC, gephyrin and GAP-43 within the adjacent visual cortex. RESULTS Our results have shown that only schizencephalic animals present increased convulsive severity. Nevertheless, both microgyric and schizencephalic cortices present increased synapse number and dendritic complexity of layer IV and layer V-located neurons. Specifically, the microgyric cortex presented reduced inhibitory synapses, while the schizencephalic cortex presented increased excitatory synapses. This altered synapse number is correlated with decreased content of both the anti-synaptogenic factor SPARC and the inhibitory postsynaptic organizer gephyrin in both malformed groups. Besides, GAP-43 content and dendritic spines number are enhanced exclusively in schizencephalic cortices. SIGNIFICANCE In conclusion, our study supports the hypothesis that the sum of synaptic alterations drives to convulsive aggravation in animals with schizencephaly, but not microgyria after PTZ treatment. These findings reveal that different malformations of cortical development should trigger epilepsy via different mechanisms, requiring further studies for development of specific therapeutic interventions.
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Affiliation(s)
- Luiza Dos Santos Heringer
- Neurodegeneration and Repair Lab, Department of Pathology, Postgraduate Program in Anatomical Pathology, Faculty of Medicine, Universitary Hospital Clementino Fraga Filho, Federal University of Rio de Janeiro, Brazil, Rio de Janeiro, - RJ
| | - Julia Rios Carvalho
- Neurodegeneration and Repair Lab, Department of Pathology, Postgraduate Program in Anatomical Pathology, Faculty of Medicine, Universitary Hospital Clementino Fraga Filho, Federal University of Rio de Janeiro, Brazil, Rio de Janeiro, - RJ
| | | | - Bruna Texeira Silva
- Laboratory of Neuroplasticity, Department of Neurobiology, Institute of Biology, Brazil, Niterói, - RJ
| | - Domethila Mariano de Souza Aguiar Dos Santos
- Neurodegeneration and Repair Lab, Department of Pathology, Postgraduate Program in Anatomical Pathology, Faculty of Medicine, Universitary Hospital Clementino Fraga Filho, Federal University of Rio de Janeiro, Brazil, Rio de Janeiro, - RJ
| | - Anna Lecticia Martinez Martinez Toledo
- Neurodegeneration and Repair Lab, Department of Pathology, Postgraduate Program in Anatomical Pathology, Faculty of Medicine, Universitary Hospital Clementino Fraga Filho, Federal University of Rio de Janeiro, Brazil, Rio de Janeiro, - RJ
| | - Laura Maria Borges Savoldi
- Neurodegeneration and Repair Lab, Department of Pathology, Postgraduate Program in Anatomical Pathology, Faculty of Medicine, Universitary Hospital Clementino Fraga Filho, Federal University of Rio de Janeiro, Brazil, Rio de Janeiro, - RJ
| | - Debora Magalhães Portela
- Integrated Lab of Morphology, Institute of Biodiversity and Sustainability NUPEM, Brazil, Macaé, - RJ
| | - Suelen Adriani Marques
- Neurodegeneration and Repair Lab, Department of Pathology, Postgraduate Program in Anatomical Pathology, Faculty of Medicine, Universitary Hospital Clementino Fraga Filho, Federal University of Rio de Janeiro, Brazil, Rio de Janeiro, - RJ
| | | | - Ana Maria Blanco Martinez
- Neurodegeneration and Repair Lab, Department of Pathology, Postgraduate Program in Anatomical Pathology, Faculty of Medicine, Universitary Hospital Clementino Fraga Filho, Federal University of Rio de Janeiro, Brazil, Rio de Janeiro, - RJ
| | - Henrique Rocha Mendonça
- Neurodegeneration and Repair Lab, Department of Pathology, Postgraduate Program in Anatomical Pathology, Faculty of Medicine, Universitary Hospital Clementino Fraga Filho, Federal University of Rio de Janeiro, Brazil, Rio de Janeiro, - RJ.,Integrated Lab of Morphology, Institute of Biodiversity and Sustainability NUPEM, Brazil, Macaé, - RJ
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