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Brignone MS, Lanciotti A, Molinari P, Mallozzi C, De Nuccio C, Caprini ES, Petrucci TC, Visentin S, Ambrosini E. Megalencephalic leukoencephalopathy with subcortical cysts protein-1: A new calcium-sensitive protein functionally activated by endoplasmic reticulum calcium release and calmodulin binding in astrocytes. Neurobiol Dis 2024; 190:106388. [PMID: 38141856 DOI: 10.1016/j.nbd.2023.106388] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 12/04/2023] [Accepted: 12/18/2023] [Indexed: 12/25/2023] Open
Abstract
BACKGROUND MLC1 is a membrane protein highly expressed in brain perivascular astrocytes and whose mutations account for the rare leukodystrophy (LD) megalencephalic leukoencephalopathy with subcortical cysts disease (MLC). MLC is characterized by macrocephaly, brain edema and cysts, myelin vacuolation and astrocyte swelling which cause cognitive and motor dysfunctions and epilepsy. In cultured astrocytes, lack of functional MLC1 disturbs cell volume regulation by affecting anion channel (VRAC) currents and the consequent regulatory volume decrease (RVD) occurring in response to osmotic changes. Moreover, MLC1 represses intracellular signaling molecules (EGFR, ERK1/2, NF-kB) inducing astrocyte activation and swelling following brain insults. Nevertheless, to date, MLC1 proper function and MLC molecular pathogenesis are still elusive. We recently reported that in astrocytes MLC1 phosphorylation by the Ca2+/Calmodulin-dependent kinase II (CaMKII) in response to intracellular Ca2+ release potentiates MLC1 activation of VRAC. These results highlighted the importance of Ca2+ signaling in the regulation of MLC1 functions, prompting us to further investigate the relationships between intracellular Ca2+ and MLC1 properties. METHODS We used U251 astrocytoma cells stably expressing wild-type (WT) or mutated MLC1, primary mouse astrocytes and mouse brain tissue, and applied biochemistry, molecular biology, video imaging and electrophysiology techniques. RESULTS We revealed that WT but not mutant MLC1 oligomerization and trafficking to the astrocyte plasma membrane is favored by Ca2+ release from endoplasmic reticulum (ER) but not by capacitive Ca2+ entry in response to ER depletion. We also clarified the molecular events underlining MLC1 response to cytoplasmic Ca2+ increase, demonstrating that, following Ca2+ release, MLC1 binds the Ca2+ effector protein calmodulin (CaM) at the carboxyl terminal where a CaM binding sequence was identified. Using a CaM inhibitor and generating U251 cells expressing MLC1 with CaM binding site mutations, we found that CaM regulates MLC1 assembly, trafficking and function, being RVD and MLC-linked signaling molecules abnormally regulated in these latter cells. CONCLUSION Overall, we qualified MLC1 as a Ca2+ sensitive protein involved in the control of volume changes in response to ER Ca2+ release and astrocyte activation. These findings provide new insights for the comprehension of the molecular mechanisms responsible for the myelin degeneration occurring in MLC and other LD where astrocytes have a primary role in the pathological process.
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Affiliation(s)
- M S Brignone
- Istituto Superiore di Sanità, Department of Neuroscience, Viale Regina Elena 299, 00161 Rome, Italy
| | - A Lanciotti
- Istituto Superiore di Sanità, Department of Neuroscience, Viale Regina Elena 299, 00161 Rome, Italy
| | - P Molinari
- Istituto Superiore di Sanità, National Center for Drug Research and Evaluation, Viale Regina Elena 299, 00161 Rome, Italy
| | - C Mallozzi
- Istituto Superiore di Sanità, Department of Neuroscience, Viale Regina Elena 299, 00161 Rome, Italy
| | - C De Nuccio
- Istituto Superiore di Sanità, Research Coordination and Support Service, Viale Regina Elena 299, 00161 Rome, Italy
| | - E S Caprini
- Istituto Superiore di Sanità, Department of Neuroscience, Viale Regina Elena 299, 00161 Rome, Italy
| | - T C Petrucci
- Istituto Superiore di Sanità, Department of Neuroscience, Viale Regina Elena 299, 00161 Rome, Italy
| | - S Visentin
- Istituto Superiore di Sanità, National Center for Drug Research and Evaluation, Viale Regina Elena 299, 00161 Rome, Italy
| | - E Ambrosini
- Istituto Superiore di Sanità, Department of Neuroscience, Viale Regina Elena 299, 00161 Rome, Italy.
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Lanciotti A, Brignone MS, Macioce P, Visentin S, Ambrosini E. Human iPSC-Derived Astrocytes: A Powerful Tool to Study Primary Astrocyte Dysfunction in the Pathogenesis of Rare Leukodystrophies. Int J Mol Sci 2021; 23:ijms23010274. [PMID: 35008700 PMCID: PMC8745131 DOI: 10.3390/ijms23010274] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 12/21/2021] [Accepted: 12/22/2021] [Indexed: 12/11/2022] Open
Abstract
Astrocytes are very versatile cells, endowed with multitasking capacities to ensure brain homeostasis maintenance from brain development to adult life. It has become increasingly evident that astrocytes play a central role in many central nervous system pathologies, not only as regulators of defensive responses against brain insults but also as primary culprits of the disease onset and progression. This is particularly evident in some rare leukodystrophies (LDs) where white matter/myelin deterioration is due to primary astrocyte dysfunctions. Understanding the molecular defects causing these LDs may help clarify astrocyte contribution to myelin formation/maintenance and favor the identification of possible therapeutic targets for LDs and other CNS demyelinating diseases. To date, the pathogenic mechanisms of these LDs are poorly known due to the rarity of the pathological tissue and the failure of the animal models to fully recapitulate the human diseases. Thus, the development of human induced pluripotent stem cells (hiPSC) from patient fibroblasts and their differentiation into astrocytes is a promising approach to overcome these issues. In this review, we discuss the primary role of astrocytes in LD pathogenesis, the experimental models currently available and the advantages, future evolutions, perspectives, and limitations of hiPSC to study pathologies implying astrocyte dysfunctions.
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Affiliation(s)
- Angela Lanciotti
- Department of Neuroscience, Istituto Superiore di Sanità, 00169 Rome, Italy; (A.L.); (M.S.B.); (P.M.)
| | - Maria Stefania Brignone
- Department of Neuroscience, Istituto Superiore di Sanità, 00169 Rome, Italy; (A.L.); (M.S.B.); (P.M.)
| | - Pompeo Macioce
- Department of Neuroscience, Istituto Superiore di Sanità, 00169 Rome, Italy; (A.L.); (M.S.B.); (P.M.)
| | - Sergio Visentin
- National Center for Research and Preclinical and Clinical Evaluation of Drugs, Istituto Superiore di Sanità, 00169 Rome, Italy;
| | - Elena Ambrosini
- Department of Neuroscience, Istituto Superiore di Sanità, 00169 Rome, Italy; (A.L.); (M.S.B.); (P.M.)
- Correspondence: ; Tel.: +39-064-990-2037
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Verkhratsky A, Li B, Scuderi C, Parpura V. Principles of Astrogliopathology. ADVANCES IN NEUROBIOLOGY 2021; 26:55-73. [PMID: 34888830 DOI: 10.1007/978-3-030-77375-5_3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The role of astrocytes in the nervous system pathology was early on embraced by neuroscientists at end of the nineteenth and the beginning of the twentieth century, only to be pushed aside by neurone-centric dogmas during most of the twentieth century. However, the last decade of the twentieth century and the twenty-first century have brought the astroglial "renaissance", which has put astroglial cells as key players in pathophysiology of most if not all disorders of the nervous system and has regarded astroglia as a fertile ground for therapeutic intervention.Astrocytic contribution to neuropathology can be primary, whereby cell-autonomous changes, such as mutations in gene encoding for glial fibrillary acidic protein, can drive the pathologic progression, in this example, Alexander disease. They can also be secondary, when astrocytes respond to a variety of insults to the nervous tissue. Regardless of their origin, being cell-autonomous or not, changes in astroglia that occur in pathology, that is, astrogliopathology, can be contemporary and arbitrary classified into four forms: (i) reactive astrogliosis, (ii) astrocytic atrophy with loss of function, (iii) pathological remodelling of astrocytes and (iv) astrodegeneration morphologically manifested as clasmatodendrosis. Inevitably, as with any other classification, this classification of astrogliopathology awaits its revision that shall be rooted in new discoveries and concepts.
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Affiliation(s)
- Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK.
- Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, Bilbao, Spain.
| | - Baoman Li
- Practical Teaching Center, School of Forensic Medicine, China Medical University, Shenyang, China
| | - Caterina Scuderi
- Department of Physiology and Pharmacology "Vittorio Erspamer", SAPIENZA University of Rome, Rome, Italy
| | - Vladimir Parpura
- Department of Neurobiology, The University of Alabama at Birmingham, Birmingham, AL, USA
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Ritter M, Bresgen N, Kerschbaum HH. From Pinocytosis to Methuosis-Fluid Consumption as a Risk Factor for Cell Death. Front Cell Dev Biol 2021; 9:651982. [PMID: 34249909 PMCID: PMC8261248 DOI: 10.3389/fcell.2021.651982] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 04/29/2021] [Indexed: 12/11/2022] Open
Abstract
The volumes of a cell [cell volume (CV)] and its organelles are adjusted by osmoregulatory processes. During pinocytosis, extracellular fluid volume equivalent to its CV is incorporated within an hour and membrane area equivalent to the cell's surface within 30 min. Since neither fluid uptake nor membrane consumption leads to swelling or shrinkage, cells must be equipped with potent volume regulatory mechanisms. Normally, cells respond to outwardly or inwardly directed osmotic gradients by a volume decrease and increase, respectively, i.e., they shrink or swell but then try to recover their CV. However, when a cell death (CD) pathway is triggered, CV persistently decreases in isotonic conditions in apoptosis and it increases in necrosis. One type of CD associated with cell swelling is due to a dysfunctional pinocytosis. Methuosis, a non-apoptotic CD phenotype, occurs when cells accumulate too much fluid by macropinocytosis. In contrast to functional pinocytosis, in methuosis, macropinosomes neither recycle nor fuse with lysosomes but with each other to form giant vacuoles, which finally cause rupture of the plasma membrane (PM). Understanding methuosis longs for the understanding of the ionic mechanisms of cell volume regulation (CVR) and vesicular volume regulation (VVR). In nascent macropinosomes, ion channels and transporters are derived from the PM. Along trafficking from the PM to the perinuclear area, the equipment of channels and transporters of the vesicle membrane changes by retrieval, addition, and recycling from and back to the PM, causing profound changes in vesicular ion concentrations, acidification, and-most importantly-shrinkage of the macropinosome, which is indispensable for its proper targeting and cargo processing. In this review, we discuss ion and water transport mechanisms with respect to CVR and VVR and with special emphasis on pinocytosis and methuosis. We describe various aspects of the complex mutual interplay between extracellular and intracellular ions and ion gradients, the PM and vesicular membrane, phosphoinositides, monomeric G proteins and their targets, as well as the submembranous cytoskeleton. Our aim is to highlight important cellular mechanisms, components, and processes that may lead to methuotic CD upon their derangement.
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Affiliation(s)
- Markus Ritter
- Center for Physiology, Pathophysiology and Biophysics, Institute for Physiology and Pathophysiology, Paracelsus Medical University, Salzburg, Austria
- Institute for Physiology and Pathophysiology, Paracelsus Medical University, Nuremberg, Germany
- Gastein Research Institute, Paracelsus Medical University, Salzburg, Austria
- Ludwig Boltzmann Institute for Arthritis und Rehabilitation, Salzburg, Austria
- Kathmandu University School of Medical Sciences, Dhulikhel, Nepal
| | - Nikolaus Bresgen
- Department of Biosciences, University of Salzburg, Salzburg, Austria
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Bosch A, Estévez R. Megalencephalic Leukoencephalopathy: Insights Into Pathophysiology and Perspectives for Therapy. Front Cell Neurosci 2021; 14:627887. [PMID: 33551753 PMCID: PMC7862579 DOI: 10.3389/fncel.2020.627887] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 12/30/2020] [Indexed: 01/13/2023] Open
Abstract
Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a rare genetic disorder belonging to the group of vacuolating leukodystrophies. It is characterized by megalencephaly, loss of motor functions, epilepsy, and mild mental decline. In brain biopsies of MLC patients, vacuoles were observed in myelin and in astrocytes surrounding blood vessels. It is mainly caused by recessive mutations in MLC1 and HEPACAM (also called GLIALCAM) genes. These disease variants are called MLC1 and MLC2A with both types of patients sharing the same clinical phenotype. Besides, dominant mutations in HEPACAM were also identified in a subtype of MLC patients (MLC2B) with a remitting phenotype. MLC1 and GlialCAM proteins form a complex mainly expressed in brain astrocytes at the gliovascular interface and in Bergmann glia at the cerebellum. Both proteins regulate several ion channels and transporters involved in the control of ion and water fluxes in glial cells, either directly influencing their location and function, or indirectly regulating associated signal transduction pathways. However, the MLC1/GLIALCAM complex function and the related pathological mechanisms leading to MLC are still unknown. It has been hypothesized that, in MLC, the role of glial cells in brain ion homeostasis is altered in both physiological and inflammatory conditions. There is no therapy for MLC patients, only supportive treatment. As MLC2B patients show an MLC reversible phenotype, we speculated that the phenotype of MLC1 and MLC2A patients could also be mitigated by the re-introduction of the correct gene even at later stages. To prove this hypothesis, we injected in the cerebellar subarachnoid space of Mlc1 knockout mice an adeno-associated virus (AAV) coding for human MLC1 under the control of the glial-fibrillary acidic protein promoter. MLC1 expression in the cerebellum extremely reduced myelin vacuolation at all ages in a dose-dependent manner. This study could be considered as the first preclinical approach for MLC. We also suggest other potential therapeutic strategies in this review.
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Affiliation(s)
- Assumpció Bosch
- Department of Biochemistry and Molecular Biology, Institute of Neurosciences, Univ. Autònoma de Barcelona, Barcelona, Spain.,Unitat Mixta UAB-VHIR, Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Raúl Estévez
- Departament de Ciències Fisiològiques, IDIBELL-Institute of Neurosciences, Universitat de Barcelona, Barcelona, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
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Wang MX, Ray L, Tanaka KF, Iliff JJ, Heys J. Varying perivascular astroglial endfoot dimensions along the vascular tree maintain perivascular-interstitial flux through the cortical mantle. Glia 2020; 69:715-728. [PMID: 33075175 DOI: 10.1002/glia.23923] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 09/17/2020] [Accepted: 10/02/2020] [Indexed: 12/18/2022]
Abstract
The glymphatic system is a recently defined brain-wide network of perivascular spaces along which cerebrospinal fluid (CSF) and interstitial solutes exchange. Astrocyte endfeet encircling the perivascular space form a physical barrier in between these two compartments, and fluid and solutes that are not taken up by astrocytes move out of the perivascular space through the junctions in between astrocyte endfeet. However, little is known about the anatomical structure and the physiological roles of the astrocyte endfeet in regulating the local perivascular exchange. Here, visualizing astrocyte endfoot-endfoot junctions with immunofluorescent labeling against the protein megalencephalic leukoencephalopathy with subcortical cysts-1 (MLC1), we characterized endfoot dimensions along the mouse cerebrovascular tree. We observed marked heterogeneity in endfoot dimensions along vessels of different sizes, and of different types. Specifically, endfoot size was positively correlated with the vessel diameters, with large vessel segments surrounded by large endfeet and small vessel segments surrounded by small endfeet. This association was most pronounced along arterial, rather than venous segments. Computational modeling simulating vascular trees with uniform or varying endfeet dimensions demonstrates that varying endfoot dimensions maintain near constant perivascular-interstitial flux despite correspondingly declining perivascular pressures along the cerebrovascular tree through the cortical depth. These results describe a novel anatomical feature of perivascular astroglial endfeet and suggest that endfoot heterogeneity may be an evolutionary adaptation to maintain perivascular CSF-interstitial fluid exchange through deep brain structures.
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Affiliation(s)
- Marie Xun Wang
- VISN 20 Mental Illness Research, Education and Clinical Center (MIRECC), VA Puget Sound Health Care System, Seattle, Washington, USA.,Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, Washington, USA
| | - Lori Ray
- Department of Chemical and Biological Engineering, Montana State University-Bozeman, Bozeman, Montana, USA
| | - Kenji F Tanaka
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan
| | - Jeffrey J Iliff
- VISN 20 Mental Illness Research, Education and Clinical Center (MIRECC), VA Puget Sound Health Care System, Seattle, Washington, USA.,Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, Washington, USA.,Department of Neurology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Jeffrey Heys
- Department of Chemical and Biological Engineering, Montana State University-Bozeman, Bozeman, Montana, USA
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Sánchez A, García-Lareu B, Puig M, Prat E, Ruberte J, Chillón M, Nunes V, Estévez R, Bosch A. Cerebellar Astrocyte Transduction as Gene Therapy for Megalencephalic Leukoencephalopathy. Neurotherapeutics 2020; 17:2041-2053. [PMID: 32372403 PMCID: PMC7851290 DOI: 10.1007/s13311-020-00865-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a rare genetic disorder belonging to the group of vacuolating leukodystrophies. It is characterized by megalencephaly, loss of motor functions, epilepsy, and mild mental decline. In brain biopsies of MLC patients, vacuoles were observed in myelin and in astrocytes surrounding blood vessels. There is no therapy for MLC patients, only supportive treatment. We show here a preclinical gene therapy approach for MLC using the Mlc1 knock-out mouse. An adeno-associated virus coding for human MLC1 under the control of the glial fibrillary acidic protein promoter was injected in the cerebellar subarachnoid space of Mlc1 knock-out and wild-type animals at 2 months of age, before the onset of the disease, as a preventive approach. We also tested a therapeutic strategy by injecting the animals at 5 months, once the histopathological abnormalities are starting, or at 15 months, when they have progressed to a more severe pathology. MLC1 expression in the cerebellum restored the adhesion molecule GlialCAM and the chloride channel ClC-2 localization in Bergmann glia, which both are mislocalized in Mlc1 knock-out model. More importantly, myelin vacuolation was extremely reduced in treated mice at all ages and correlated with the amount of expressed MLC1 in Bergmann glia, indicating not only the preventive potential of this strategy but also its therapeutic capacity. In summary, here we provide the first therapeutic approach for patients affected with MLC. This work may have also implications to treat other diseases affecting motor function such as ataxias.
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Affiliation(s)
- Angela Sánchez
- Department of Biochemistry and Molecular Biology and Institute of Neurosciences, Edifici H, Universitat Autònoma de Barcelona, E-08193, Bellaterra, Spain
- Unitat Mixta UAB-VHIR, Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain
| | - Belén García-Lareu
- Department of Biochemistry and Molecular Biology and Institute of Neurosciences, Edifici H, Universitat Autònoma de Barcelona, E-08193, Bellaterra, Spain
| | - Meritxell Puig
- Department of Biochemistry and Molecular Biology and Institute of Neurosciences, Edifici H, Universitat Autònoma de Barcelona, E-08193, Bellaterra, Spain
- Unitat Mixta UAB-VHIR, Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain
| | - Esther Prat
- Laboratori de Genètica Molecular, Programa de Genes, Malaltia i Teràpia, IDIBELL, L'Hospitalet de Llobregat, Barcelona, Spain
- Unitat de Genètica, Departament de Ciències Fisiològiques, Facultad de Medicina i Ciències de la Salut, Univ. de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Jesús Ruberte
- Department of Animal Health and Anatomy and Center of Animal Biotechnology and Gene Therapy (CBATEG), Univ. Autònoma de Barcelona, Barcelona, Spain
| | - Miguel Chillón
- Department of Biochemistry and Molecular Biology and Institute of Neurosciences, Edifici H, Universitat Autònoma de Barcelona, E-08193, Bellaterra, Spain
- Unitat Mixta UAB-VHIR, Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain
- Institut Català de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
| | - Virginia Nunes
- Laboratori de Genètica Molecular, Programa de Genes, Malaltia i Teràpia, IDIBELL, L'Hospitalet de Llobregat, Barcelona, Spain
- Unitat de Genètica, Departament de Ciències Fisiològiques, Facultad de Medicina i Ciències de la Salut, Univ. de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Raul Estévez
- Centro de Investigación Biomédica en Red sobre Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Madrid, Spain.
- Departament de Ciències Fisiològiques, IDIBELL - Institute of Neurosciences, Universitat de Barcelona, E-08907, Barcelona, Spain.
| | - Assumpció Bosch
- Department of Biochemistry and Molecular Biology and Institute of Neurosciences, Edifici H, Universitat Autònoma de Barcelona, E-08193, Bellaterra, Spain.
- Unitat Mixta UAB-VHIR, Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain.
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain.
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Megalencephalic Leukoencephalopathy with Subcortical Cysts Disease-Linked MLC1 Protein Favors Gap-Junction Intercellular Communication by Regulating Connexin 43 Trafficking in Astrocytes. Cells 2020; 9:cells9061425. [PMID: 32521795 PMCID: PMC7348769 DOI: 10.3390/cells9061425] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 05/29/2020] [Accepted: 06/03/2020] [Indexed: 01/06/2023] Open
Abstract
Astrocytes, the most numerous cells of the central nervous system, exert critical functions for brain homeostasis. To this purpose, astrocytes generate a highly interconnected intercellular network allowing rapid exchange of ions and metabolites through gap junctions, adjoined channels composed of hexamers of connexin (Cx) proteins, mainly Cx43. Functional alterations of Cxs and gap junctions have been observed in several neuroinflammatory/neurodegenerative diseases. In the rare leukodystrophy megalencephalic leukoencephalopathy with subcortical cysts (MLC), astrocytes show defective control of ion/fluid exchanges causing brain edema, fluid cysts, and astrocyte/myelin vacuolation. MLC is caused by mutations in MLC1, an astrocyte-specific protein of elusive function, and in GlialCAM, a MLC1 chaperon. Both proteins are highly expressed at perivascular astrocyte end-feet and astrocyte-astrocyte contacts where they interact with zonula occludens-1 (ZO-1) and Cx43 junctional proteins. To investigate the possible role of Cx43 in MLC pathogenesis, we studied Cx43 properties in astrocytoma cells overexpressing wild type (WT) MLC1 or MLC1 carrying pathological mutations. Using biochemical and electrophysiological techniques, we found that WT, but not mutated, MLC1 expression favors intercellular communication by inhibiting extracellular-signal-regulated kinase 1/2 (ERK1/2)-mediated Cx43 phosphorylation and increasing Cx43 gap-junction stability. These data indicate MLC1 regulation of Cx43 in astrocytes and Cx43 involvement in MLC pathogenesis, suggesting potential target pathways for therapeutic interventions.
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Abstract
Leukodystrophies are genetically determined disorders affecting the white matter of the central nervous system. The combination of MRI pattern recognition and next-generation sequencing for the definition of novel disease entities has recently demonstrated that many leukodystrophies are due to the primary involvement and/or mutations in genes selectively expressed by cell types other than the oligodendrocytes, the myelin-forming cells in the brain. This has led to a new definition of leukodystrophies as genetic white matter disorders resulting from the involvement of any white matter structural component. As a result, the research has shifted its main focus from oligodendrocytes to other types of neuroglia. Astrocytes are the housekeeping cells of the nervous system, responsible for maintaining homeostasis and normal brain physiology and to orchestrate repair upon injury. Several lines of evidence show that astrocytic interactions with the other white matter cellular constituents play a primary pathophysiologic role in many leukodystrophies. These are thus now classified as astrocytopathies. This chapter addresses how the crosstalk between astrocytes, other glial cells, axons and non-neural cells are essential for the integrity and maintenance of the white matter in health. It also addresses the current knowledge of the cellular pathomechanisms of astrocytic leukodystrophies, and specifically Alexander disease, vanishing white matter, megalencephalic leukoencephalopathy with subcortical cysts and Aicardi-Goutière Syndrome.
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Affiliation(s)
- M S Jorge
- Department of Pathology, Free University Medical Centre, Amsterdam, The Netherlands
| | - Marianna Bugiani
- Department of Pathology, Free University Medical Centre, Amsterdam, The Netherlands.
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Megalencephalic Leukoencephalopathy with Subcortical Cysts Protein-1 (MLC1) Counteracts Astrocyte Activation in Response to Inflammatory Signals. Mol Neurobiol 2019; 56:8237-8254. [DOI: 10.1007/s12035-019-01657-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 05/20/2019] [Indexed: 01/08/2023]
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Göttle P, Förster M, Gruchot J, Kremer D, Hartung HP, Perron H, Küry P. Rescuing the negative impact of human endogenous retrovirus envelope protein on oligodendroglial differentiation and myelination. Glia 2018; 67:160-170. [PMID: 30430656 DOI: 10.1002/glia.23535] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 08/30/2018] [Accepted: 08/31/2018] [Indexed: 12/17/2022]
Abstract
Remyelination in the adult CNS depends on activation, differentiation, and functional integration of resident oligodendroglial precursor cells (OPCs) and constitutes the only spontaneous neuroregenerative process able to compensate for functional deficits upon loss of oligodendrocytes and myelin sheaths as it is observed in multiple sclerosis. The proteins encoded by p57kip2- and by human endogenous retrovirus type W (pHERV-W) envelope genes were previously identified as negative regulators of OPC maturation. We here focused on the activity of the ENV protein and investigated how it can be neutralized for an improved myelin repair. We could demonstrate that myelination in vitro is severely affected by this protein but that application of an anti-ENV neutralizing antibody, currently investigated in clinical trials, can rescue the generation of internodes. We then compared p57kip2 and ENV dependent inhibitory mechanisms and found that a dominant negative version of the p57kip2 protein can equally save OPCs from myelination failure in response to ENV-mediated TLR4 activation. Additional experiments addressing p57kip2's underlying mode of action revealed a direct interaction with ATP6v1d, a central component of a vascular ATPase. Its pharmacological blocking was then shown to exert an analogous myelination rescue effect in presence of the ENV protein. Therefore, our study provides mechanistic insights into oligodendroglial inhibition processes and presents three different means to counteract the anti-myelination effect of the ENV protein. These observations are therefore of interest in light of understanding the complexity of the numerous oligodendroglial inhibitors and might promote the establishment of novel regenerative therapies.
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Affiliation(s)
- Peter Göttle
- Department of Neurology, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
| | - Moritz Förster
- Department of Neurology, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
| | - Joel Gruchot
- Department of Neurology, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
| | - David Kremer
- Department of Neurology, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
| | - Hans Peter Hartung
- Department of Neurology, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
| | - Hervé Perron
- GeNeuro, Chemin du Pré-Fleuri 3, Geneva, Switzerland
| | - Patrick Küry
- Department of Neurology, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
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Elorza-Vidal X, Sirisi S, Gaitán-Peñas H, Pérez-Rius C, Alonso-Gardón M, Armand-Ugón M, Lanciotti A, Brignone MS, Prat E, Nunes V, Ambrosini E, Gasull X, Estévez R. GlialCAM/MLC1 modulates LRRC8/VRAC currents in an indirect manner: Implications for megalencephalic leukoencephalopathy. Neurobiol Dis 2018; 119:88-99. [DOI: 10.1016/j.nbd.2018.07.031] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 07/25/2018] [Accepted: 07/28/2018] [Indexed: 01/09/2023] Open
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13
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Estévez R, Elorza-Vidal X, Gaitán-Peñas H, Pérez-Rius C, Armand-Ugón M, Alonso-Gardón M, Xicoy-Espaulella E, Sirisi S, Arnedo T, Capdevila-Nortes X, López-Hernández T, Montolio M, Duarri A, Teijido O, Barrallo-Gimeno A, Palacín M, Nunes V. Megalencephalic leukoencephalopathy with subcortical cysts: A personal biochemical retrospective. Eur J Med Genet 2018; 61:50-60. [DOI: 10.1016/j.ejmg.2017.10.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 09/14/2017] [Accepted: 10/22/2017] [Indexed: 12/22/2022]
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14
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Sirisi S, Elorza-Vidal X, Arnedo T, Armand-Ugón M, Callejo G, Capdevila-Nortes X, López-Hernández T, Schulte U, Barrallo-Gimeno A, Nunes V, Gasull X, Estévez R. Depolarization causes the formation of a ternary complex between GlialCAM, MLC1 and ClC-2 in astrocytes: implications in megalencephalic leukoencephalopathy. Hum Mol Genet 2017; 26:2436-2450. [DOI: 10.1093/hmg/ddx134] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 03/29/2017] [Indexed: 01/06/2023] Open
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15
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Gain-of-function defects of astrocytic Kir4.1 channels in children with autism spectrum disorders and epilepsy. Sci Rep 2016; 6:34325. [PMID: 27677466 PMCID: PMC5039625 DOI: 10.1038/srep34325] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 09/07/2016] [Indexed: 12/23/2022] Open
Abstract
Dysfunction of the inwardly-rectifying potassium channels Kir4.1 (KCNJ10) represents a pathogenic mechanism contributing to Autism-Epilepsy comorbidity. To define the role of Kir4.1 variants in the disorder, we sequenced KCNJ10 in a sample of affected individuals, and performed genotype-phenotype correlations. The effects of mutations on channel activity, protein trafficking, and astrocyte function were investigated in Xenopus laevis oocytes, and in human astrocytoma cell lines. An in vivo model of the disorder was also explored through generation of kcnj10a morphant zebrafish overexpressing the mutated human KCNJ10. We detected germline heterozygous KCNJ10 variants in 19/175 affected children. Epileptic spasms with dysregulated sensory processing represented the main disease phenotype. When investigated on astrocyte-like cells, the p.R18Q mutation exerted a gain-of-function effect by enhancing Kir4.1 membrane expression and current density. Similarly, the p.R348H variant led to gain of channel function through hindrance of pH-dependent current inhibition. The frequent polymorphism p.R271C seemed, instead, to have no obvious functional effects. Our results confirm that variants in KCNJ10 deserve attention in autism-epilepsy, and provide insight into the molecular mechanisms of autism and seizures. Similar to neurons, astrocyte dysfunction may result in abnormal synaptic transmission and electrical discharge, and should be regarded as a possible pharmacological target in autism-epilepsy.
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16
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Chandrasekaran A, Avci HX, Leist M, Kobolák J, Dinnyés A. Astrocyte Differentiation of Human Pluripotent Stem Cells: New Tools for Neurological Disorder Research. Front Cell Neurosci 2016; 10:215. [PMID: 27725795 PMCID: PMC5035736 DOI: 10.3389/fncel.2016.00215] [Citation(s) in RCA: 103] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 08/30/2016] [Indexed: 12/22/2022] Open
Abstract
Astrocytes have a central role in brain development and function, and so have gained increasing attention over the past two decades. Consequently, our knowledge about their origin, differentiation and function has increased significantly, with new research showing that astrocytes cultured alone or co-cultured with neurons have the potential to improve our understanding of various central nervous system diseases, such as amyotrophic lateral sclerosis, Alzheimer’s disease, or Alexander disease. The generation of astrocytes derived from pluripotent stem cells (PSCs) opens up a new area for studying neurologic diseases in vitro; these models could be exploited to identify and validate potential drugs by detecting adverse effects in the early stages of drug development. However, as it is now known that a range of astrocyte populations exist in the brain, it will be important in vitro to develop standardized protocols for the in vitro generation of astrocyte subsets with defined maturity status and phenotypic properties. This will then open new possibilities for co-cultures with neurons and the generation of neural organoids for research purposes. The aim of this review article is to compare and summarize the currently available protocols and their strategies to generate human astrocytes from PSCs. Furthermore, we discuss the potential role of human-induced PSCs derived astrocytes in disease modeling.
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Affiliation(s)
| | - Hasan X Avci
- BioTalentum LtdGödöllő, Hungary; Department of Medical Chemistry, University of SzegedSzeged, Hungary
| | - Marcel Leist
- Dorenkamp-Zbinden Chair, Faculty of Mathematics and Sciences, University of Konstanz Konstanz, Germany
| | | | - Andras Dinnyés
- BioTalentum LtdGödöllő, Hungary; Molecular Animal Biotechnology Laboratory, Szent Istvan UniversityGödöllő, Hungary
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17
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Boscia F, Begum G, Pignataro G, Sirabella R, Cuomo O, Casamassa A, Sun D, Annunziato L. Glial Na(+) -dependent ion transporters in pathophysiological conditions. Glia 2016; 64:1677-97. [PMID: 27458821 DOI: 10.1002/glia.23030] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Revised: 06/22/2016] [Accepted: 06/29/2016] [Indexed: 12/12/2022]
Abstract
Sodium dynamics are essential for regulating functional processes in glial cells. Indeed, glial Na(+) signaling influences and regulates important glial activities, and plays a role in neuron-glia interaction under physiological conditions or in response to injury of the central nervous system (CNS). Emerging studies indicate that Na(+) pumps and Na(+) -dependent ion transporters in astrocytes, microglia, and oligodendrocytes regulate Na(+) homeostasis and play a fundamental role in modulating glial activities in neurological diseases. In this review, we first briefly introduced the emerging roles of each glial cell type in the pathophysiology of cerebral ischemia, Alzheimer's disease, epilepsy, Parkinson's disease, Amyotrophic Lateral Sclerosis, and myelin diseases. Then, we discussed the current knowledge on the main roles played by the different glial Na(+) -dependent ion transporters, including Na(+) /K(+) ATPase, Na(+) /Ca(2+) exchangers, Na(+) /H(+) exchangers, Na(+) -K(+) -Cl(-) cotransporters, and Na(+) - HCO3- cotransporter in the pathophysiology of the diverse CNS diseases. We highlighted their contributions in cell survival, synaptic pathology, gliotransmission, pH homeostasis, and their role in glial activation, migration, gliosis, inflammation, and tissue repair processes. Therefore, this review summarizes the foundation work for targeting Na(+) -dependent ion transporters in glia as a novel strategy to control important glial activities associated with Na(+) dynamics in different neurological disorders. GLIA 2016;64:1677-1697.
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Affiliation(s)
- Francesca Boscia
- Division of Pharmacology, Department of Neuroscience, Reproductive, and Odontostomatological Sciences, School of Medicine, Federico II University of Naples, Naples, Italy
| | - Gulnaz Begum
- Department of Neurology, University of Pittsburgh Medical School
| | - Giuseppe Pignataro
- Division of Pharmacology, Department of Neuroscience, Reproductive, and Odontostomatological Sciences, School of Medicine, Federico II University of Naples, Naples, Italy
| | - Rossana Sirabella
- Division of Pharmacology, Department of Neuroscience, Reproductive, and Odontostomatological Sciences, School of Medicine, Federico II University of Naples, Naples, Italy
| | - Ornella Cuomo
- Division of Pharmacology, Department of Neuroscience, Reproductive, and Odontostomatological Sciences, School of Medicine, Federico II University of Naples, Naples, Italy
| | - Antonella Casamassa
- Division of Pharmacology, Department of Neuroscience, Reproductive, and Odontostomatological Sciences, School of Medicine, Federico II University of Naples, Naples, Italy
| | - Dandan Sun
- Department of Neurology, University of Pittsburgh Medical School.,Veterans Affairs Pittsburgh Health Care System, Geriatric Research, Educational and Clinical Center, Pittsburgh, Pennsylvania, 15213
| | - Lucio Annunziato
- Division of Pharmacology, Department of Neuroscience, Reproductive, and Odontostomatological Sciences, School of Medicine, Federico II University of Naples, Naples, Italy
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18
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Lanciotti A, Brignone MS, Visentin S, De Nuccio C, Catacuzzeno L, Mallozzi C, Petrini S, Caramia M, Veroni C, Minnone G, Bernardo A, Franciolini F, Pessia M, Bertini E, Petrucci TC, Ambrosini E. Megalencephalic leukoencephalopathy with subcortical cysts protein-1 regulates epidermal growth factor receptor signaling in astrocytes. Hum Mol Genet 2016; 25:1543-58. [DOI: 10.1093/hmg/ddw032] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 02/03/2016] [Indexed: 01/13/2023] Open
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19
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Brignone MS, Lanciotti A, Camerini S, De Nuccio C, Petrucci TC, Visentin S, Ambrosini E. MLC1 protein: a likely link between leukodystrophies and brain channelopathies. Front Cell Neurosci 2015; 9:66. [PMID: 25883547 PMCID: PMC4381631 DOI: 10.3389/fncel.2015.00106] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 03/09/2015] [Indexed: 01/12/2023] Open
Abstract
Megalencephalic leukoencephalopathy with subcortical cysts (MLCs) disease is a rare inherited, autosomal recessive form of childhood-onset spongiform leukodystrophy characterized by macrocephaly, deterioration of motor functions, epileptic seizures and mental decline. Brain edema, subcortical fluid cysts, myelin and astrocyte vacuolation are the histopathological hallmarks of MLC. Mutations in either the MLC1 gene (>75% of patients) or the GlialCAM gene (<20% of patients) are responsible for the disease. Recently, the GlialCAM adhesion protein was found essential for the membrane expression and function of the chloride channel ClC-2 indicating MLC disease caused by mutation in GlialCAM as the first channelopathy among leukodystrophies. On the contrary, the function of MLC1 protein, which binds GlialCAM, its functional relationship with ClC-2 and the molecular mechanisms underlying MLC1 mutation-induced functional defects are not fully understood yet. The human MLC1 gene encodes a 377-amino acid membrane protein with eight predicted transmembrane domains which shows very low homology with voltage-dependent potassium (K+) channel subunits. The high expression of MLC1 in brain astrocytes contacting blood vessels and meninges and brain alterations observed in MLC patients have led to hypothesize a role for MLC1 in the regulation of ion and water homeostasis. Recent studies have shown that MLC1 establishes structural and/or functional interactions with several ion/water channels and transporters and ion channel accessory proteins, and that these interactions are affected by MLC1 mutations causing MLC. Here, we review data on MLC1 functional properties obtained in in vitro and in vivo models and discuss evidence linking the effects of MLC1 mutations to brain channelopathies.
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Affiliation(s)
- Maria S Brignone
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità Rome, Italy
| | - Angela Lanciotti
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità Rome, Italy
| | - Serena Camerini
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità Rome, Italy
| | - Chiara De Nuccio
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità Rome, Italy
| | - Tamara C Petrucci
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità Rome, Italy
| | - Sergio Visentin
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità Rome, Italy
| | - Elena Ambrosini
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità Rome, Italy
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