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Valles SL, Singh SK, Campos-Campos J, Colmena C, Campo-Palacio I, Alvarez-Gamez K, Caballero O, Jorda A. Functions of Astrocytes under Normal Conditions and after a Brain Disease. Int J Mol Sci 2023; 24:ijms24098434. [PMID: 37176144 PMCID: PMC10179527 DOI: 10.3390/ijms24098434] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Revised: 04/26/2023] [Accepted: 05/05/2023] [Indexed: 05/15/2023] Open
Abstract
In the central nervous system (CNS) there are a greater number of glial cells than neurons (between five and ten times more). Furthermore, they have a greater number of functions (more than eight functions). Glia comprises different types of cells, those of neural origin (astrocytes, radial glia, and oligodendroglia) and differentiated blood monocytes (microglia). During ontogeny, neurons develop earlier (at fetal day 15 in the rat) and astrocytes develop later (at fetal day 21 in the rat), which could indicate their important and crucial role in the CNS. Analysis of the phylogeny reveals that reptiles have a lower number of astrocytes compared to neurons and in humans this is reversed, as there have a greater number of astrocytes compared to neurons. These data perhaps imply that astrocytes are important and special cells, involved in many vital functions, including memory, and learning processes. In addition, astrocytes are involved in different mechanisms that protect the CNS through the production of antioxidant and anti-inflammatory proteins and they clean the extracellular environment and help neurons to communicate correctly with each other. The production of inflammatory mediators is important to prevent changes in brain homeostasis. On the contrary, excessive, or continued production appears as a characteristic element in many diseases, such as Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), multiple sclerosis (MS), and in neurodevelopmental diseases, such as bipolar disorder, schizophrenia, and autism. Furthermore, different drugs and techniques have been developed to reverse oxidative stress and/or excess of inflammation that occurs in many CNS diseases, but much remains to be investigated. This review attempts to highlight the functional relevance of astrocytes in normal and neuropathological conditions by showing the molecular and cellular mechanisms of their role in the CNS.
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Affiliation(s)
- Soraya L Valles
- Department of Physiology, School of Medicine, University of Valencia, Blasco Ibañez 15, 46010 Valencia, Spain
| | - Sandeep Kumar Singh
- Indian Scientific Education and Technology Foundation, Lucknow 226002, India
| | - Juan Campos-Campos
- Department of Physiology, School of Medicine, University of Valencia, Blasco Ibañez 15, 46010 Valencia, Spain
- Faculty of Nursing and Podiatry, University of Valencia, 46010 Valencia, Spain
| | - Carlos Colmena
- Department of Physiology, School of Medicine, University of Valencia, Blasco Ibañez 15, 46010 Valencia, Spain
| | - Ignacio Campo-Palacio
- Department of Physiology, School of Medicine, University of Valencia, Blasco Ibañez 15, 46010 Valencia, Spain
| | - Kenia Alvarez-Gamez
- Department of Physiology, School of Medicine, University of Valencia, Blasco Ibañez 15, 46010 Valencia, Spain
| | - Oscar Caballero
- Department of Physiology, School of Medicine, University of Valencia, Blasco Ibañez 15, 46010 Valencia, Spain
- Faculty of Nursing and Podiatry, University of Valencia, 46010 Valencia, Spain
| | - Adrian Jorda
- Department of Physiology, School of Medicine, University of Valencia, Blasco Ibañez 15, 46010 Valencia, Spain
- Faculty of Nursing and Podiatry, University of Valencia, 46010 Valencia, Spain
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Garcia LM, Hacker JL, Sase S, Adang L, Almad A. Glial cells in the driver seat of leukodystrophy pathogenesis. Neurobiol Dis 2020; 146:105087. [PMID: 32977022 DOI: 10.1016/j.nbd.2020.105087] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 08/16/2020] [Accepted: 09/18/2020] [Indexed: 01/24/2023] Open
Abstract
Glia cells are often viewed as support cells in the central nervous system, but recent discoveries highlight their importance in physiological functions and in neurological diseases. Central to this are leukodystrophies, a group of progressive, neurogenetic disease affecting white matter pathology. In this review, we take a closer look at multiple leukodystrophies, classified based on the primary glial cell type that is affected. While white matter diseases involve oligodendrocyte and myelin loss, we discuss how astrocytes and microglia are affected and impinge on oligodendrocyte, myelin and axonal pathology. We provide an overview of the leukodystrophies covering their hallmark features, clinical phenotypes, diverse molecular pathways, and potential therapeutics for clinical trials. Glial cells are gaining momentum as cellular therapeutic targets for treatment of demyelinating diseases such as leukodystrophies, currently with no treatment options. Here, we bring the much needed attention to role of glia in leukodystrophies, an integral step towards furthering disease comprehension, understanding mechanisms and developing future therapeutics.
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Affiliation(s)
- Luis M Garcia
- Department of Neurology, The Children's Hospital of Philadelphia, PA, Pennsylvania, USA
| | - Julia L Hacker
- Department of Neurology, The Children's Hospital of Philadelphia, PA, Pennsylvania, USA
| | - Sunetra Sase
- Department of Neurology, The Children's Hospital of Philadelphia, PA, Pennsylvania, USA
| | - Laura Adang
- Department of Neurology, The Children's Hospital of Philadelphia, PA, Pennsylvania, USA
| | - Akshata Almad
- Department of Neurology, The Children's Hospital of Philadelphia, PA, Pennsylvania, USA.
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Benbenishty A, Gadrich M, Cottarelli A, Lubart A, Kain D, Amer M, Shaashua L, Glasner A, Erez N, Agalliu D, Mayo L, Ben-Eliyahu S, Blinder P. Prophylactic TLR9 stimulation reduces brain metastasis through microglia activation. PLoS Biol 2019; 17:e2006859. [PMID: 30921319 PMCID: PMC6469801 DOI: 10.1371/journal.pbio.2006859] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2018] [Revised: 04/17/2019] [Accepted: 02/28/2019] [Indexed: 02/07/2023] Open
Abstract
Brain metastases are prevalent in various types of cancer and are often terminal, given the low efficacy of available therapies. Therefore, preventing them is of utmost clinical relevance, and prophylactic treatments are perhaps the most efficient strategy. Here, we show that systemic prophylactic administration of a toll-like receptor (TLR) 9 agonist, CpG-C, is effective against brain metastases. Acute and chronic systemic administration of CpG-C reduced tumor cell seeding and growth in the brain in three tumor models in mice, including metastasis of human and mouse lung cancer, and spontaneous melanoma-derived brain metastasis. Studying mechanisms underlying the therapeutic effects of CpG-C, we found that in the brain, unlike in the periphery, natural killer (NK) cells and monocytes are not involved in controlling metastasis. Next, we demonstrated that the systemically administered CpG-C is taken up by endothelial cells, astrocytes, and microglia, without affecting blood-brain barrier (BBB) integrity and tumor brain extravasation. In vitro assays pointed to microglia, but not astrocytes, as mediators of CpG- C effects through increased tumor killing and phagocytosis, mediated by direct microglia-tumor contact. In vivo, CpG-C-activated microglia displayed elevated mRNA expression levels of apoptosis-inducing and phagocytosis-related genes. Intravital imaging showed that CpG-C-activated microglia cells contact, kill, and phagocytize tumor cells in the early stages of tumor brain invasion more than nonactivated microglia. Blocking in vivo activation of microglia with minocycline, and depletion of microglia with a colony-stimulating factor 1 inhibitor, indicated that microglia mediate the antitumor effects of CpG-C. Overall, the results suggest prophylactic CpG-C treatment as a new intervention against brain metastasis, through an essential activation of microglia.
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Affiliation(s)
- Amit Benbenishty
- School of Psychological Sciences, Tel Aviv University, Tel Aviv, Israel
- Neurobiology Department, Tel Aviv University, Tel Aviv, Israel
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Meital Gadrich
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
- School for Molecular Cell Biology & Biotechnology, Tel Aviv University, Tel Aviv, Israel
| | - Azzurra Cottarelli
- Department of Neurology, Columbia University Medical Center, New York, New York, United States of America
| | - Alisa Lubart
- Neurobiology Department, Tel Aviv University, Tel Aviv, Israel
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - David Kain
- Neurobiology Department, Tel Aviv University, Tel Aviv, Israel
| | - Malak Amer
- Department of Pathology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Lee Shaashua
- School of Psychological Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Ariella Glasner
- The Lautenberg Centre for General and Tumor Immunology, The Hebrew University Hadassah Medical School, Jerusalem, Israel
| | - Neta Erez
- Department of Pathology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Dritan Agalliu
- Department of Neurology, Columbia University Medical Center, New York, New York, United States of America
| | - Lior Mayo
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
- School for Molecular Cell Biology & Biotechnology, Tel Aviv University, Tel Aviv, Israel
| | - Shamgar Ben-Eliyahu
- School of Psychological Sciences, Tel Aviv University, Tel Aviv, Israel
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Pablo Blinder
- Neurobiology Department, Tel Aviv University, Tel Aviv, Israel
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
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