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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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Stogsdill JA, Harwell CC, Goldman SA. Astrocytes as master modulators of neural networks: Synaptic functions and disease-associated dysfunction of astrocytes. Ann N Y Acad Sci 2023; 1525:41-60. [PMID: 37219367 DOI: 10.1111/nyas.15004] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Astrocytes are the most abundant glial cell type in the central nervous system and are essential to the development, plasticity, and maintenance of neural circuits. Astrocytes are heterogeneous, with their diversity rooted in developmental programs modulated by the local brain environment. Astrocytes play integral roles in regulating and coordinating neural activity extending far beyond their metabolic support of neurons and other brain cell phenotypes. Both gray and white matter astrocytes occupy critical functional niches capable of modulating brain physiology on time scales slower than synaptic activity but faster than those adaptive responses requiring a structural change or adaptive myelination. Given their many associations and functional roles, it is not surprising that astrocytic dysfunction has been causally implicated in a broad set of neurodegenerative and neuropsychiatric disorders. In this review, we focus on recent discoveries concerning the contributions of astrocytes to the function of neural networks, with a dual focus on the contribution of astrocytes to synaptic development and maturation, and on their role in supporting myelin integrity, and hence conduction and its regulation. We then address the emerging roles of astrocytic dysfunction in disease pathogenesis and on potential strategies for targeting these cells for therapeutic purposes.
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Affiliation(s)
| | - Corey C Harwell
- Department of Neurology, University of California San Francisco, San Francisco, California, USA
| | - Steven A Goldman
- Sana Biotechnology Inc., Cambridge, Massachusetts, USA
- Center for Translational Neuromedicine, University of Rochester, Rochester, New York, USA
- University of Copenhagen Faculty of Health and Medical Sciences, Copenhagen, Denmark
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3
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Brignone MS, Lanciotti A, Michelucci A, Mallozzi C, Camerini S, Catacuzzeno L, Sforna L, Caramia M, D’Adamo MC, Ceccarini M, Molinari P, Macioce P, Macchia G, Petrucci TC, Pessia M, Visentin S, Ambrosini E. The CaMKII/MLC1 Axis Confers Ca2+-Dependence to Volume-Regulated Anion Channels (VRAC) in Astrocytes. Cells 2022; 11:cells11172656. [PMID: 36078064 PMCID: PMC9454758 DOI: 10.3390/cells11172656] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 08/18/2022] [Accepted: 08/24/2022] [Indexed: 11/30/2022] Open
Abstract
Astrocytes, the main glial cells of the central nervous system, play a key role in brain volume control due to their intimate contacts with cerebral blood vessels and the expression of a distinctive equipment of proteins involved in solute/water transport. Among these is MLC1, a protein highly expressed in perivascular astrocytes and whose mutations cause megalencephalic leukoencephalopathy with subcortical cysts (MLC), an incurable leukodystrophy characterized by macrocephaly, chronic brain edema, cysts, myelin vacuolation, and astrocyte swelling. Although, in astrocytes, MLC1 mutations are known to affect the swelling-activated chloride currents (ICl,swell) mediated by the volume-regulated anion channel (VRAC), and the regulatory volume decrease, MLC1′s proper function is still unknown. By combining molecular, biochemical, proteomic, electrophysiological, and imaging techniques, we here show that MLC1 is a Ca2+/Calmodulin-dependent protein kinase II (CaMKII) target protein, whose phosphorylation, occurring in response to intracellular Ca2+ release, potentiates VRAC-mediated ICl,swell. Overall, these findings reveal that MLC1 is a Ca2+-regulated protein, linking volume regulation to Ca2+ signaling in astrocytes. This knowledge provides new insight into the MLC1 protein function and into the mechanisms controlling ion/water exchanges in the brain, which may help identify possible molecular targets for the treatment of MLC and other pathological conditions caused by astrocyte swelling and brain edema.
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Affiliation(s)
| | - Angela Lanciotti
- Department of Neuroscience, Istituto Superiore di Sanità, 00169 Rome, Italy
| | - Antonio Michelucci
- Department of Chemistry, Biology and Biotechnology, University of Perugia, 06123 Perugia, Italy
| | - Cinzia Mallozzi
- Department of Neuroscience, Istituto Superiore di Sanità, 00169 Rome, Italy
| | - Serena Camerini
- Core Facilities (FAST), Istituto Superiore di Sanità, 00169 Rome, Italy
| | - Luigi Catacuzzeno
- Department of Chemistry, Biology and Biotechnology, University of Perugia, 06123 Perugia, Italy
| | - Luigi Sforna
- Department of Chemistry, Biology and Biotechnology, University of Perugia, 06123 Perugia, Italy
| | - Martino Caramia
- Department of Chemistry, Biology and Biotechnology, University of Perugia, 06123 Perugia, Italy
| | - Maria Cristina D’Adamo
- Department of Medicine and Surgery, LUM Giuseppe Degennaro University, 70010 Bari, Italy
| | - Marina Ceccarini
- National Centre for Rare Diseases, Istituto Superiore di Sanità, 00169 Rome, Italy
| | - Paola Molinari
- National Centre for Drug Research and Evaluation (FARVA), Istituto Superiore di Sanità, 00169 Rome, Italy
| | - Pompeo Macioce
- Department of Neuroscience, Istituto Superiore di Sanità, 00169 Rome, Italy
| | | | | | - Mauro Pessia
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, MSD2080 Msida, Malta
- Department of Physiology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain P.O. Box 17666, United Arab Emirates
| | - Sergio Visentin
- National Centre for Drug Research and Evaluation (FARVA), Istituto Superiore di Sanità, 00169 Rome, Italy
| | - Elena Ambrosini
- Department of Neuroscience, Istituto Superiore di Sanità, 00169 Rome, Italy
- Correspondence: ; Tel.: +39-06-4990-2037
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4
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GPR37 Receptors and Megalencephalic Leukoencephalopathy with Subcortical Cysts. Int J Mol Sci 2022; 23:ijms23105528. [PMID: 35628339 PMCID: PMC9144339 DOI: 10.3390/ijms23105528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 05/12/2022] [Accepted: 05/13/2022] [Indexed: 11/30/2022] Open
Abstract
Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a rare type of vacuolating leukodystrophy (white matter disorder), which is mainly caused by defects in MLC1 or glial cell adhesion molecule (GlialCAM) proteins. In addition, autoantibodies to GlialCAM are involved in the pathology of multiple sclerosis. MLC1 and GLIALCAM genes encode for membrane proteins of unknown function, which has been linked to the regulation of different ion channels and transporters, such as the chloride channel VRAC (volume regulated anion channel), ClC-2 (chloride channel 2), and connexin 43 or the Na+/K+-ATPase pump. However, the mechanisms by which MLC proteins regulate these ion channels and transporters, as well as the exact function of MLC proteins remain obscure. It has been suggested that MLC proteins might regulate signalling pathways, but the mechanisms involved are, at present, unknown. With the aim of answering these questions, we have recently described the brain GlialCAM interactome. Within the identified proteins, we could validate the interaction with several G protein-coupled receptors (GPCRs), including the orphan GPRC5B and the proposed prosaposin receptors GPR37L1 and GPR37. In this review, we summarize new aspects of the pathophysiology of MLC disease and key aspects of the interaction between GPR37 receptors and MLC proteins.
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Wang BB, Xu H, Isenmann S, Huang C, Elorza-Vidal X, Rychkov GY, Estévez R, Schittenhelm RB, Lukacs GL, Apaja PM. Ubr1-induced selective endophagy/autophagy protects against the endosomal and Ca 2+-induced proteostasis disease stress. Cell Mol Life Sci 2022; 79:167. [PMID: 35233680 PMCID: PMC8888484 DOI: 10.1007/s00018-022-04191-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 01/30/2022] [Accepted: 02/04/2022] [Indexed: 12/15/2022]
Abstract
The cellular defense mechanisms against cumulative endo-lysosomal stress remain incompletely understood. Here, we identify Ubr1 as a protein quality control (QC) E3 ubiquitin-ligase that counteracts proteostasis stresses by facilitating endosomal cargo-selective autophagy for lysosomal degradation. Astrocyte regulatory cluster membrane protein MLC1 mutations cause endosomal compartment stress by fusion and enlargement. Partial lysosomal clearance of mutant endosomal MLC1 is accomplished by the endosomal QC ubiquitin ligases, CHIP and Ubr1 via ESCRT-dependent route. As a consequence of the endosomal stress, a supportive QC mechanism, dependent on both Ubr1 and SQSTM1/p62 activities, targets ubiquitinated and arginylated MLC1 mutants for selective endosomal autophagy (endophagy). This QC pathway is also activated for arginylated Ubr1-SQSTM1/p62 autophagy cargoes during cytosolic Ca2+-assault. Conversely, the loss of Ubr1 and/or arginylation elicited endosomal compartment stress. These findings underscore the critical housekeeping role of Ubr1 and arginylation-dependent endophagy/autophagy during endo-lysosomal proteostasis perturbations and suggest a link of Ubr1 to Ca2+ homeostasis and proteins implicated in various diseases including cancers and brain disorders.
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Affiliation(s)
- Ben B Wang
- Lifelong Health, Organelle Proteostasis Diseases, South Australian Health and Medical Research Institute (SAHMRI), 5000 North Terrace, Adelaide, SA, 5000, Australia.,EMBL Australia, Adelaide, South Australia, 5000, Australia
| | - Haijin Xu
- Department of Physiology and Cell Information Systems, McGill University, 3655 Promenade Sir-William-Osler, Montréal, QC, H3G 1Y6, Canada
| | - Sandra Isenmann
- Lifelong Health, Organelle Proteostasis Diseases, South Australian Health and Medical Research Institute (SAHMRI), 5000 North Terrace, Adelaide, SA, 5000, Australia.,EMBL Australia, Adelaide, South Australia, 5000, Australia
| | - Cheng Huang
- Monash Biomedical Proteomics Facility, Department of Biochemistry, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Xabier Elorza-Vidal
- Unitat de Fisiologia, Departament de Ciències Fisiològiques, IDIBELL-Institute of Neurosciences, L'Hospitalet de Llobregat, Universitat de Barcelona, Barcelona, Spain.,Centro de Investigación en Red de Enfermedades Raras (CIBERER), ISCIII, Madrid, Spain
| | - Grigori Y Rychkov
- Lifelong Health, Organelle Proteostasis Diseases, South Australian Health and Medical Research Institute (SAHMRI), 5000 North Terrace, Adelaide, SA, 5000, Australia.,School of Medicine, University of Adelaide, Adelaide, SA, 5005, Australia
| | - Raúl Estévez
- Unitat de Fisiologia, Departament de Ciències Fisiològiques, IDIBELL-Institute of Neurosciences, L'Hospitalet de Llobregat, Universitat de Barcelona, Barcelona, Spain.,Centro de Investigación en Red de Enfermedades Raras (CIBERER), ISCIII, Madrid, Spain
| | - Ralf B Schittenhelm
- Monash Biomedical Proteomics Facility, Department of Biochemistry, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Gergely L Lukacs
- Department of Physiology and Cell Information Systems, McGill University, 3655 Promenade Sir-William-Osler, Montréal, QC, H3G 1Y6, Canada. .,Department of Biochemistry, McGill University, Montréal, QC, H3G 1Y6, Canada.
| | - Pirjo M Apaja
- Lifelong Health, Organelle Proteostasis Diseases, South Australian Health and Medical Research Institute (SAHMRI), 5000 North Terrace, Adelaide, SA, 5000, Australia. .,EMBL Australia, Adelaide, South Australia, 5000, Australia. .,Department of Molecular and Biomedical Sciences, University of Adelaide, Adelaide, SA, 5005, Australia. .,College of Public Health and Medicine, Molecular Biosciences Theme, Flinders University, Bedford Park, SA, 5042, Australia.
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6
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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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Control of membrane protein homeostasis by a chaperone-like glial cell adhesion molecule at multiple subcellular locations. Sci Rep 2021; 11:18435. [PMID: 34531445 PMCID: PMC8446001 DOI: 10.1038/s41598-021-97777-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 08/24/2021] [Indexed: 01/17/2023] Open
Abstract
The significance of crosstalks among constituents of plasma membrane protein clusters/complexes in cellular proteostasis and protein quality control (PQC) remains incompletely understood. Examining the glial (enriched) cell adhesion molecule (CAM), we demonstrate its chaperone-like role in the biosynthetic processing of the megalencephalic leukoencephalopathy with subcortical cyst 1 (MLC1)-heteromeric regulatory membrane protein complex, as well as the function of the GlialCAM/MLC1 signalling complex. We show that in the absence of GlialCAM, newly synthesized MLC1 molecules remain unfolded and are susceptible to polyubiquitination-dependent proteasomal degradation at the endoplasmic reticulum. At the plasma membrane, GlialCAM regulates the diffusional partitioning and endocytic dynamics of cluster members, including the ClC-2 chloride channel and MLC1. Impaired folding and/or expression of GlialCAM or MLC1 in the presence of diseases causing mutations, as well as plasma membrane tethering compromise the functional expression of the cluster, leading to compromised endo-lysosomal organellar identity. In addition, the enlarged endo-lysosomal compartments display accelerated acidification, ubiquitinated cargo-sorting and impaired endosomal recycling. Jointly, these observations indicate an essential and previously unrecognized role for CAM, where GliaCAM functions as a PQC factor for the MLC1 signalling complex biogenesis and possess a permissive role in the membrane dynamic and cargo sorting functions with implications in modulations of receptor signalling.
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Alonso-Gardón M, Elorza-Vidal X, Castellanos A, La Sala G, Armand-Ugon M, Gilbert A, Di Pietro C, Pla-Casillanis A, Ciruela F, Gasull X, Nunes V, Martínez A, Schulte U, Cohen-Salmon M, Marazziti D, Estévez R. Identification of the GlialCAM interactome: the G protein-coupled receptors GPRC5B and GPR37L1 modulate megalencephalic leukoencephalopathy proteins. Hum Mol Genet 2021; 30:1649-1665. [PMID: 34100078 PMCID: PMC8369841 DOI: 10.1093/hmg/ddab155] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/31/2021] [Accepted: 06/01/2021] [Indexed: 12/23/2022] Open
Abstract
Megalencephalic Leukoencephalopathy with subcortical Cysts (MLC) is a type of vacuolating leukodystrophy, which is mainly caused by mutations in MLC1 or GLIALCAM. The two MLC-causing genes encode for membrane proteins of yet unknown function that have been linked to the regulation of different chloride channels such as the ClC-2 and VRAC. To gain insight into the role of MLC proteins, we have determined the brain GlialCAM interacting proteome. The proteome includes different transporters and ion channels known to be involved in the regulation of brain homeostasis, proteins related to adhesion or signaling as several G protein-coupled receptors (GPCRs), including the orphan GPRC5B and the proposed prosaposin receptor GPR37L1. Focusing on these two GPCRs, we could validate that they interact directly with MLC proteins. The inactivation of Gpr37l1 in mice upregulated MLC proteins without altering their localization. Conversely, a reduction of GPRC5B levels in primary astrocytes downregulated MLC proteins, leading to an impaired activation of ClC-2 and VRAC. The interaction between the GPCRs and MLC1 was dynamically regulated upon changes in the osmolarity or potassium concentration. We propose that GlialCAM and MLC1 associate with different integral membrane proteins modulating their functions and acting as a recruitment site for various signaling components as the GPCRs identified here. We hypothesized that the GlialCAM/MLC1 complex is working as an adhesion molecule coupled to a tetraspanin-like molecule performing regulatory effects through direct binding or influencing signal transduction events.
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Affiliation(s)
- Marta Alonso-Gardón
- Departament de Ciències Fisiològiques, Genes Disease and Therapy Program IDIBELL - Institute of Neurosciences, Universitat de Barcelona, Barcelona 08036, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Madrid 28029, Spain
| | - Xabier Elorza-Vidal
- Departament de Ciències Fisiològiques, Genes Disease and Therapy Program IDIBELL - Institute of Neurosciences, Universitat de Barcelona, Barcelona 08036, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Madrid 28029, Spain
| | - Aida Castellanos
- Departament de Ciències Fisiològiques, Genes Disease and Therapy Program IDIBELL - Institute of Neurosciences, Universitat de Barcelona, Barcelona 08036, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Madrid 28029, Spain
| | - Gina La Sala
- Institute of Biochemistry and Cell Biology, Italian National Research Council (CNR), Monterotondo Scalo, Rome I-00015, Italy
| | - Mercedes Armand-Ugon
- Departament de Ciències Fisiològiques, Genes Disease and Therapy Program IDIBELL - Institute of Neurosciences, Universitat de Barcelona, Barcelona 08036, Spain
| | - Alice Gilbert
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, Paris F-75005, France
| | - Chiara Di Pietro
- Institute of Biochemistry and Cell Biology, Italian National Research Council (CNR), Monterotondo Scalo, Rome I-00015, Italy
| | - Adrià Pla-Casillanis
- Departament de Ciències Fisiològiques, Genes Disease and Therapy Program IDIBELL - Institute of Neurosciences, Universitat de Barcelona, Barcelona 08036, Spain
| | - Francisco Ciruela
- Pharmacology Unit, Department of Pathology and Experimental Therapeutics, Faculty of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona-IDIBELL, L'Hospitalet de Llobregat, Barcelona 08036, Spain
| | - Xavier Gasull
- Neurophysiology Laboratory, Department of Biomedicine, Medical School, Institute of Neurosciences, University of Barcelona-IDIBAPS, Casanova 143 Barcelona 08036, Spain
| | - Virginia Nunes
- Unitat de Genètica, Departament de Ciències Fisiològiques, Universitat de Barcelona, Laboratori de Genètica Molecular, Genes Disease and Therapy Program IDIBELL, L'Hospitalet de Llobregat 08036, Spain
| | - Albert Martínez
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology, University of Barcelona, Barcelona 08028, Spain
| | | | - Martine Cohen-Salmon
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, Paris F-75005, France
| | - Daniela Marazziti
- Institute of Biochemistry and Cell Biology, Italian National Research Council (CNR), Monterotondo Scalo, Rome I-00015, Italy
| | - Raúl Estévez
- Departament de Ciències Fisiològiques, Genes Disease and Therapy Program IDIBELL - Institute of Neurosciences, Universitat de Barcelona, Barcelona 08036, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Madrid 28029, Spain
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Bai H, Zhou R, Barravecchia M, Norman R, Friedman A, Yu D, Lin X, Young JL, Dean DA. The Na+, K+-ATPase β1 subunit regulates epithelial tight junctions via MRCKα. JCI Insight 2021; 6:134881. [PMID: 33507884 PMCID: PMC7934944 DOI: 10.1172/jci.insight.134881] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 01/13/2021] [Indexed: 12/12/2022] Open
Abstract
An intact lung epithelial barrier is essential for lung homeostasis. The Na+, K+-ATPase (NKA), primarily serving as an ion transporter, also regulates epithelial barrier function via modulation of tight junctions. However, the underlying mechanism is not well understood. Here, we show that overexpression of the NKA β1 subunit upregulates the expression of tight junction proteins, leading to increased alveolar epithelial barrier function by an ion transport–independent mechanism. Using IP and mass spectrometry, we identified a number of unknown protein interactions of the β1 subunit, including a top candidate, myotonic dystrophy kinase–related cdc42-binding kinase α (MRCKα), which is a protein kinase known to regulate peripheral actin formation. Using a doxycycline-inducible gene expression system, we demonstrated that MRCKα and its downstream activation of myosin light chain is required for the regulation of alveolar barrier function by the NKA β1 subunit. Importantly, MRCKα is expressed in both human airways and alveoli and has reduced expression in patients with acute respiratory distress syndrome (ARDS), a lung illness that can be caused by multiple direct and indirect insults, including the infection of influenza virus and SARS-CoV-2. Our results have elucidated a potentially novel mechanism by which NKA regulates epithelial tight junctions and have identified potential drug targets for treating ARDS and other pulmonary diseases that are caused by barrier dysfunction.
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Affiliation(s)
- Haiqing Bai
- Department of Pediatrics and.,Department of Pathology, School of Medicine and Dentistry, University of Rochester, Rochester, New York, USA
| | | | | | | | - Alan Friedman
- Department of Pediatrics and.,Department of Materials Design and Innovation, School of Engineering and Applied Sciences, University at Buffalo, Buffalo, New York, USA
| | | | - Xin Lin
- Department of Pediatrics and
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Baasch Christensen I, Cheng L, Brewer JR, Bartsch U, Fenton RA, Damkier HH, Praetorius J. Multiple Na,K-ATPase Subunits Colocalize in the Brush Border of Mouse Choroid Plexus Epithelial Cells. Int J Mol Sci 2021; 22:ijms22041569. [PMID: 33557294 PMCID: PMC7915972 DOI: 10.3390/ijms22041569] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Accepted: 01/29/2021] [Indexed: 01/24/2023] Open
Abstract
(1) Background: The unusual accumulation of Na,K-ATPase complexes in the brush border membrane of choroid plexus epithelial cells have intrigued researchers for decades. However, the full range of the expressed Na,K-ATPase subunits and their relation to the microvillus cytoskeleton remains unknown. (2) Methods: RT-PCR analysis, co-immunoprecipitation, native PAGE, mass spectrometry, and differential centrifugation were combined with high-resolution immunofluorescence histochemistry, proximity ligase assays, and stimulated emission depletion (STED) microscopy on mouse choroid plexus cells or tissues in order to resolve these issues. (3) Results: The choroid plexus epithelium expresses Na,K-ATPase subunits α1, α2, β1, β2, β3, and phospholemman. The α1, α2, β1, and β2, subunits are all localized to the brush border membrane, where they appear to form a complex. The ATPase complexes may stabilize in the brush border membrane via anchoring to microvillar actin indirectly through ankyrin-3 or directly via other co-precipitated proteins. Aquaporin 1 (AQP1) may form part of the proposed multi-protein complexes in contrast to another membrane protein, the Na-K-2Cl cotransporter 1 (NKCC1). NKCC1 expression seems necessary for full brush border membrane accumulation of the Na,K-ATPase in the choroid plexus. (4) Conclusion: A multitude of Na,K-ATPase subunits form molecular complexes in the choroid plexus brush border, which may bind to the cytoskeleton by various alternative actin binding proteins.
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Affiliation(s)
- Inga Baasch Christensen
- Department of Biomedicine, Faculty of Health Science, Aarhus University, 8000 Aarhus, Denmark; (I.B.C.); (L.C.); (R.A.F.); (H.H.D.)
| | - Lei Cheng
- Department of Biomedicine, Faculty of Health Science, Aarhus University, 8000 Aarhus, Denmark; (I.B.C.); (L.C.); (R.A.F.); (H.H.D.)
| | - Jonathan R. Brewer
- Department of Biochemistry and Molecular Biology, Faculty of Science, University of Southern Denmark, 5230 Odense, Denmark;
| | - Udo Bartsch
- Department of Ophthalmology, Experimental Ophthalmology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany;
| | - Robert A. Fenton
- Department of Biomedicine, Faculty of Health Science, Aarhus University, 8000 Aarhus, Denmark; (I.B.C.); (L.C.); (R.A.F.); (H.H.D.)
| | - Helle H. Damkier
- Department of Biomedicine, Faculty of Health Science, Aarhus University, 8000 Aarhus, Denmark; (I.B.C.); (L.C.); (R.A.F.); (H.H.D.)
| | - Jeppe Praetorius
- Department of Biomedicine, Faculty of Health Science, Aarhus University, 8000 Aarhus, Denmark; (I.B.C.); (L.C.); (R.A.F.); (H.H.D.)
- Correspondence: ; Tel.: +45-61820576
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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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12
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Lattier JM, De A, Chen Z, Morales JE, Lang FF, Huse JT, McCarty JH. Megalencephalic leukoencephalopathy with subcortical cysts 1 (MLC1) promotes glioblastoma cell invasion in the brain microenvironment. Oncogene 2020; 39:7253-7264. [PMID: 33040087 PMCID: PMC7736299 DOI: 10.1038/s41388-020-01503-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 09/17/2020] [Accepted: 09/30/2020] [Indexed: 12/13/2022]
Abstract
Glioblastoma (GBM), or grade IV astrocytoma, is a malignant brain cancer that contains subpopulations of proliferative and invasive cells that coordinately drive primary tumor growth, progression, and recurrence after therapy. Here, we have analyzed functions for megalencephalic leukoencephalopathy with subcortical cysts 1 (Mlc1), an eight-transmembrane protein normally expressed in perivascular brain astrocyte end feet that is essential for neurovascular development and physiology, in the pathogenesis of GBM. We show that Mlc1 is expressed in human stem-like GBM cells (GSCs) and is linked to the development of primary and recurrent GBM. Genetically inhibiting MLC1 in GSCs using RNAi-mediated gene silencing results in diminished growth and invasion in vitro as well as impaired tumor initiation and progression in vivo. Biochemical assays identify the receptor tyrosine kinase Axl and its intracellular signaling effectors as important for MLC1 control of GSC invasive growth. Collectively, these data reveal key functions for MLC1 in promoting GSC growth and invasion, and suggest that targeting the Mlc1 protein or its associated signaling effectors may be a useful therapy for blocking tumor progression in patients with primary or recurrent GBM.
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Affiliation(s)
- John M Lattier
- Departments of Neurosurgery, University of Texas M.D. Anderson Cancer Center, Houston, TX, USA
| | - Arpan De
- Departments of Neurosurgery, University of Texas M.D. Anderson Cancer Center, Houston, TX, USA
| | - Zhihua Chen
- Departments of Neurosurgery, University of Texas M.D. Anderson Cancer Center, Houston, TX, USA
| | - John E Morales
- Departments of Neurosurgery, University of Texas M.D. Anderson Cancer Center, Houston, TX, USA
| | - Frederick F Lang
- Departments of Neurosurgery, University of Texas M.D. Anderson Cancer Center, Houston, TX, USA
| | - Jason T Huse
- Translational Molecular Pathology, University of Texas M.D. Anderson Cancer Center, Houston, TX, USA
| | - Joseph H McCarty
- Departments of Neurosurgery, University of Texas M.D. Anderson Cancer Center, Houston, TX, USA.
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13
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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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15
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Schaffenrath J, Keller A. New Insights in the Complexity and Functionality of the Neurovascular Unit. Handb Exp Pharmacol 2020; 273:33-57. [PMID: 33582883 DOI: 10.1007/164_2020_424] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The neurovascular unit (NVU) encompasses all brain cells and underlines that neurons, glia and brain vasculature are in intimate physical and functional association. Brain function is dependent on blood flow and local increases in blood flow in response to neural activity - functional hyperaemia takes place at the NVU. Although this is a vital function of the NVU, many studies have demonstrated that the NVU also performs other tasks. Blood vessels in the brain, which are composed of multiple cell types, are essential for correct brain development. They constitute the niche for brain stem cells, sense the environment and communicate changes to neural tissue, and control the immune quiescence of the CNS. In this brief chapter we will discuss new insights into the biology of NVU, which have further revealed the heterogeneity and complexity of the vascular tree and its neurovascular associations.
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Affiliation(s)
- Johanna Schaffenrath
- Department of Neurosurgery, Clinical Neuroscience Center, Zurich Neuroscience Center, Zurich University Hospital, Zurich University, Zurich, Switzerland
| | - Annika Keller
- Department of Neurosurgery, Clinical Neuroscience Center, Zurich Neuroscience Center, Zurich University Hospital, Zurich University, Zurich, Switzerland.
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16
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Hwang J, Vu HM, Kim MS, Lim HH. Plasma membrane localization of MLC1 regulates cellular morphology and motility. Mol Brain 2019; 12:116. [PMID: 31888684 PMCID: PMC6938022 DOI: 10.1186/s13041-019-0540-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 12/18/2019] [Indexed: 01/01/2023] Open
Abstract
Background Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a rare form of infantile-onset leukodystrophy. The disorder is caused primarily by mutations of MLC1 that leads to a series of phenotypic outcomes including vacuolation of myelin and astrocytes, subcortical cysts, brain edema, and macrocephaly. Recent studies have indicated that functional interactions among MLC1, GlialCAM, and ClC-2 channels play key roles in the regulation of neuronal, glial and vascular homeostasis. However, the physiological role of MLC1 in cellular homeostatic communication remains poorly understood. In the present study, we investigated the cellular function of MLC1 and its effects on cell–cell interactions. Methods MLC1-dependent cellular morphology and motility were analyzed by using confocal and live cell imaging technique. Biochemical approaches such as immunoblotting, co-immunoprecipitation, and surface biotinylation were conducted to support data. Results We found that the altered MLC1 expression and localization led to a great alteration in cellular morphology and motility through actin remodeling. MLC1 overexpression induced filopodia formation and suppressed motility. And, MLC1 proteins expressed in patient-derived MLC1 mutants resulted in trapping in the ER although no changes in morphology or motility were observed. Interestingly knockdown of Mlc1 induced Arp3-Cortactin interaction, lamellipodia formation, and increased the membrane ruffling of the astrocytes. These data indicate that subcellular localization of expressed MLC1 at the plasma membrane is critical for changes in actin dynamics through ARP2/3 complex. Thus, our results suggest that misallocation of pathogenic mutant MLC1 may disturbs the stable cell-cell communication and the homeostatic regulation of astrocytes in patients with MLC.
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Affiliation(s)
- Junmo Hwang
- Molecular Physiology and Biophysics Laboratory, Neurovascular Unit Research Group, Korea Brain Research Institute (KBRI), 41062, Daegu, Republic of Korea
| | - Hung M Vu
- Department of New Biology, Daegu Gyeongbuk Institute of Science & Technology (DGIST), 42988, Daegu, Republic of Korea
| | - Min-Sik Kim
- Department of New Biology, Daegu Gyeongbuk Institute of Science & Technology (DGIST), 42988, Daegu, Republic of Korea
| | - Hyun-Ho Lim
- Molecular Physiology and Biophysics Laboratory, Neurovascular Unit Research Group, Korea Brain Research Institute (KBRI), 41062, Daegu, Republic of Korea. .,Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology (DGIST), 42988, Daegu, Republic of Korea.
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17
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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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18
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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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19
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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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Baldissera MD, Müller LKF, Souza CF, Santurio JM, Gloria EM, Machado G, Boiago MM, Paiano D, da Silva AS. Creatine kinase and ATPase activities in piglets fed a fungal mycotoxin co-contaminated diet: Consequences in the pathogenesis of subclinical intoxication. Microb Pathog 2018; 122:13-18. [PMID: 29852206 DOI: 10.1016/j.micpath.2018.05.044] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 04/24/2018] [Accepted: 05/27/2018] [Indexed: 12/27/2022]
Abstract
Creatine kinase (CK) activity, through the creatine-kinase-phosphocreatine (CK/PCr) system, provides a temporal and spatial energy buffer to maintain cellular energetic homeostasis, being responsible to provide adenosine triphosphate (ATP) to the proper function of ATPases enzymes, such as the sodium-potassium (Na+, K+-ATPase) and hydrogen (H+-ATPase) pumps. Thus, the aim of this study was to evaluate the involvement of CK/PCr system in the impairment of energetic homeostasis in piglets fed with a diet co-contaminated with mycotoxins, as well as the effects on ATPases enzymes. Animals were randomly divided in two groups (eight repetitions with two animals each): CON (basal diet) and MYC (mycotoxin diet; 9300 μg/kg of aflatoxins and 8000 μg/kg of fumonisins) which were feed during 15 days. Piglets that received a diet containing 300 μg/kg of aflatoxins and 8000 μg/kg of fumonisins (MYC group) presented lower body weight on days 10 and 15 of experiment when compared to control (CON group). Serum CK activity was lower on days 5, 10 and 15 of experiment in the MYC group. The same occurred for serum Na+, K+-ATPase and H+-ATPase activities on days 10 and 15 when compared to CON group. Moreover, serum calcium levels were superior on day 15 of experiment in the MYC group, while serum potassium and sodium levels were lower in comparison to CON group. Based on these evidences, a diet co-contaminated by aflatoxins and fumonisins inhibits serum CK activity, impairing the energetic homeostasis. This inhibition alters the activities of ATPases (Na+, K+-ATPase and H+-ATPase), contributing to the imbalance of Na+, K+ and Ca+ ionic levels. In summary, the cascade of alterations contributes directly to disease pathogenesis of piglets intoxicated by mycotoxins.
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Affiliation(s)
- Matheus D Baldissera
- Post Graduate Program in Pharmacology, Universidade Federal de Santa Maria (UFSM), Santa Maria, RS, Brazil; Department of Microbiology and Parasitology, UFSM, Santa Maria, RS, Brazil
| | - Lucieli K F Müller
- Post Graduate Program in Animal Science, Universidade do Estado de Santa Catarina (UDESC), Chapecó, SC, Brazil
| | - Carine F Souza
- Department of Microbiology and Parasitology, UFSM, Santa Maria, RS, Brazil
| | - Janio M Santurio
- Department of Microbiology and Parasitology, UFSM, Santa Maria, RS, Brazil
| | | | - Gustavo Machado
- Department of Population Health and Pathobiology, College of Veterinary Medicine North Carolina State University, Raleigh, EUA, United States
| | - Marcel M Boiago
- Post Graduate Program in Pharmacology, Universidade Federal de Santa Maria (UFSM), Santa Maria, RS, Brazil
| | - Diovani Paiano
- Post Graduate Program in Pharmacology, Universidade Federal de Santa Maria (UFSM), Santa Maria, RS, Brazil.
| | - Aleksandro S da Silva
- Post Graduate Program in Pharmacology, Universidade Federal de Santa Maria (UFSM), Santa Maria, RS, Brazil.
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Interaction of DCF1 with ATP1B1 induces impairment in astrocyte structural plasticity via the P38 signaling pathway. Exp Neurol 2018; 302:214-229. [DOI: 10.1016/j.expneurol.2018.01.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 12/16/2017] [Accepted: 01/08/2018] [Indexed: 12/18/2022]
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22
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Dubey M, Brouwers E, Hamilton EM, Stiedl O, Bugiani M, Koch H, Kole MH, Boschert U, Wykes RC, Mansvelder HD, van der Knaap MS, Min R. Seizures and disturbed brain potassium dynamics in the leukodystrophy megalencephalic leukoencephalopathy with subcortical cysts. Ann Neurol 2018; 83:636-649. [PMID: 29466841 PMCID: PMC5900999 DOI: 10.1002/ana.25190] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 01/12/2018] [Accepted: 02/18/2018] [Indexed: 12/26/2022]
Abstract
OBJECTIVE Loss of function of the astrocyte-specific protein MLC1 leads to the childhood-onset leukodystrophy "megalencephalic leukoencephalopathy with subcortical cysts" (MLC). Studies on isolated cells show a role for MLC1 in astrocyte volume regulation and suggest that disturbed brain ion and water homeostasis is central to the disease. Excitability of neuronal networks is particularly sensitive to ion and water homeostasis. In line with this, reports of seizures and epilepsy in MLC patients exist. However, systematic assessment and mechanistic understanding of seizures in MLC are lacking. METHODS We analyzed an MLC patient inventory to study occurrence of seizures in MLC. We used two distinct genetic mouse models of MLC to further study epileptiform activity and seizure threshold through wireless extracellular field potential recordings. Whole-cell patch-clamp recordings and K+ -sensitive electrode recordings in mouse brain slices were used to explore the underlying mechanisms of epilepsy in MLC. RESULTS An early onset of seizures is common in MLC. Similarly, in MLC mice, we uncovered spontaneous epileptiform brain activity and a lowered threshold for induced seizures. At the cellular level, we found that although passive and active properties of individual pyramidal neurons are unchanged, extracellular K+ dynamics and neuronal network activity are abnormal in MLC mice. INTERPRETATION Disturbed astrocyte regulation of ion and water homeostasis in MLC causes hyperexcitability of neuronal networks and seizures. These findings suggest a role for defective astrocyte volume regulation in epilepsy. Ann Neurol 2018;83:636-649.
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Affiliation(s)
- Mohit Dubey
- Department of Child Neurology, Amsterdam NeuroscienceVU University Medical CenterAmsterdamThe Netherlands
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam NeuroscienceVU UniversityAmsterdamThe Netherlands
- Present address:
Current address for Mohit Dubey: Department of Axonal SignalingNetherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and SciencesAmsterdamThe Netherlands
| | - Eelke Brouwers
- Department of Child Neurology, Amsterdam NeuroscienceVU University Medical CenterAmsterdamThe Netherlands
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam NeuroscienceVU UniversityAmsterdamThe Netherlands
| | - Eline M.C. Hamilton
- Department of Child Neurology, Amsterdam NeuroscienceVU University Medical CenterAmsterdamThe Netherlands
| | - Oliver Stiedl
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Amsterdam NeuroscienceVU UniversityAmsterdamThe Netherlands
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam NeuroscienceVU UniversityAmsterdamThe Netherlands
| | - Marianna Bugiani
- Department of Child Neurology, Amsterdam NeuroscienceVU University Medical CenterAmsterdamThe Netherlands
- Department of PathologyVU University Medical CenterAmsterdamThe Netherlands
| | - Henner Koch
- Department of NeurologyUniversity of Tübingen, Hertie Institute for Clinical Brain ResearchTübingenGermany
| | - Maarten H.P. Kole
- Department of Axonal SignalingNetherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and SciencesAmsterdamThe Netherlands
- Cell Biology, Faculty of ScienceUtrecht UniversityUtrechtThe Netherlands
| | - Ursula Boschert
- Translational Innovation Platform Immunology/Neurology, EMD Serono Research & Development InstituteBillericaMA
| | - Robert C. Wykes
- Department of Clinical & Experimental Epilepsy, UCL Institute of NeurologyUniversity College LondonLondonUnited Kingdom
| | - Huibert D. Mansvelder
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam NeuroscienceVU UniversityAmsterdamThe Netherlands
| | - Marjo S. van der Knaap
- Department of Child Neurology, Amsterdam NeuroscienceVU University Medical CenterAmsterdamThe Netherlands
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Amsterdam NeuroscienceVU UniversityAmsterdamThe Netherlands
| | - Rogier Min
- Department of Child Neurology, Amsterdam NeuroscienceVU University Medical CenterAmsterdamThe Netherlands
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam NeuroscienceVU UniversityAmsterdamThe Netherlands
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Simon MJ, Murchison C, Iliff JJ. A transcriptome-based assessment of the astrocytic dystrophin-associated complex in the developing human brain. J Neurosci Res 2018; 96:180-193. [PMID: 28509351 PMCID: PMC5995340 DOI: 10.1002/jnr.24082] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 03/23/2017] [Accepted: 04/20/2017] [Indexed: 11/10/2022]
Abstract
Astrocytes play a critical role in regulating the interface between the cerebral vasculature and the central nervous system. Contributing to this is the astrocytic endfoot domain, a specialized structure that ensheathes the entirety of the vasculature and mediates signaling between endothelial cells, pericytes, and neurons. The astrocytic endfoot has been implicated as a critical element of the glymphatic pathway, and changes in protein expression profiles in this cellular domain are linked to Alzheimer's disease pathology. Despite this, basic physiological properties of this structure remain poorly understood including the developmental timing of its formation, and the protein components that localize there to mediate its functions. Here we use human transcriptome data from male and female subjects across several developmental stages and brain regions to characterize the gene expression profile of the dystrophin-associated complex (DAC), a known structural component of the astrocytic endfoot that supports perivascular localization of the astroglial water channel aquaporin-4. Transcriptomic profiling is also used to define genes exhibiting parallel expression profiles to DAC elements, generating a pool of candidate genes that encode gene products that may contribute to the physiological function of the perivascular astrocytic endfoot domain. We found that several genes encoding transporter proteins are transcriptionally associated with DAC genes.
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Affiliation(s)
- Matthew J. Simon
- Neuroscience Graduate Program, Oregon Health & Science University, Portland, OR, USA
- Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, OR, USA
| | - Charles Murchison
- Department of Neurology, Oregon Health & Science University, Portland, OR, USA
| | - Jeffrey J. Iliff
- Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, OR, USA
- Knight Cardiovascular Institute. Oregon Health & Science University, Portland, OR, USA
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24
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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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25
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van der Knaap MS, Bugiani M. Leukodystrophies: a proposed classification system based on pathological changes and pathogenetic mechanisms. Acta Neuropathol 2017; 134:351-382. [PMID: 28638987 PMCID: PMC5563342 DOI: 10.1007/s00401-017-1739-1] [Citation(s) in RCA: 222] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 06/06/2017] [Accepted: 06/06/2017] [Indexed: 12/29/2022]
Abstract
Leukodystrophies are genetically determined disorders characterized by the selective involvement of the central nervous system white matter. Onset may be at any age, from prenatal life to senescence. Many leukodystrophies are degenerative in nature, but some only impair white matter function. The clinical course is mostly progressive, but may also be static or even improving with time. Progressive leukodystrophies are often fatal, and no curative treatment is known. The last decade has witnessed a tremendous increase in the number of defined leukodystrophies also owing to a diagnostic approach combining magnetic resonance imaging pattern recognition and next generation sequencing. Knowledge on white matter physiology and pathology has also dramatically built up. This led to the recognition that only few leukodystrophies are due to mutations in myelin- or oligodendrocyte-specific genes, and many are rather caused by defects in other white matter structural components, including astrocytes, microglia, axons and blood vessels. We here propose a novel classification of leukodystrophies that takes into account the primary involvement of any white matter component. Categories in this classification are the myelin disorders due to a primary defect in oligodendrocytes or myelin (hypomyelinating and demyelinating leukodystrophies, leukodystrophies with myelin vacuolization); astrocytopathies; leuko-axonopathies; microgliopathies; and leuko-vasculopathies. Following this classification, we illustrate the neuropathology and disease mechanisms of some leukodystrophies taken as example for each category. Some leukodystrophies fall into more than one category. Given the complex molecular and cellular interplay underlying white matter pathology, recognition of the cellular pathology behind a disease becomes crucial in addressing possible treatment strategies.
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Affiliation(s)
- Marjo S van der Knaap
- Department of Pediatrics/Child Neurology, VU University Medical Centre, Amsterdam Neuroscience, Amsterdam, The Netherlands
- Department of Functional Genomics, Centre for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University, Amsterdam, The Netherlands
| | - Marianna Bugiani
- Department of Pediatrics/Child Neurology, VU University Medical Centre, Amsterdam Neuroscience, Amsterdam, The Netherlands.
- Department of Pathology, VU University Medical Centre, Amsterdam Neuroscience, Amsterdam, The Netherlands.
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26
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Bugiani M, Dubey M, Breur M, Postma NL, Dekker MP, Ter Braak T, Boschert U, Abbink TEM, Mansvelder HD, Min R, van Weering JRT, van der Knaap MS. Megalencephalic leukoencephalopathy with cysts: the Glialcam-null mouse model. Ann Clin Transl Neurol 2017; 4:450-465. [PMID: 28695146 PMCID: PMC5497535 DOI: 10.1002/acn3.405] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Revised: 02/28/2017] [Accepted: 03/02/2017] [Indexed: 12/23/2022] Open
Abstract
Objective Megalencephalic leukoencephalopathy with cysts (MLC) is a genetic infantile‐onset disease characterized by macrocephaly and white matter edema due to loss of MLC1 function. Recessive mutations in either MLC1 or GLIALCAM cause the disease. MLC1 is involved in astrocytic volume regulation; GlialCAM ensures the correct membrane localization of MLC1. Their exact role in brain ion‐water homeostasis is only partly defined. We characterized Glialcam‐null mice for further studies. Methods We investigated the consequences of loss of GlialCAM in Glialcam‐null mice and compared GlialCAM developmental expression in mice and men. Results Glialcam‐null mice had early‐onset megalencephaly and increased brain water content. From 3 weeks, astrocytes were abnormal with swollen processes abutting blood vessels. Concomitantly, progressive white matter vacuolization developed due to intramyelinic edema. Glialcam‐null astrocytes showed abolished expression of MLC1, reduced expression of the chloride channel ClC‐2 and increased expression and redistribution of the water channel aquaporin4. Expression of other MLC1‐interacting proteins and the volume regulated anion channel LRRC8A was unchanged. In mice, GlialCAM expression increased until 3 weeks and then stabilized. In humans, GlialCAM expression was highest in the first 3 years to then decrease and stabilize from approximately 5 years. Interpretation Glialcam‐null mice replicate the early stages of the human disease with early‐onset intramyelinic edema. The earliest change is astrocytic swelling, further substantiating that a defect in astrocytic volume regulation is the primary cellular defect in MLC. GlialCAM expression affects expression of MLC1, ClC‐2 and aquaporin4, indicating that abnormal interplay between these proteins is a disease mechanism in megalencephalic leukoencephalopathy with cysts.
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Affiliation(s)
- Marianna Bugiani
- Department of Pediatrics/Child Neurology Amsterdam Neuroscience VU University Medical Center Amsterdam The Netherlands.,Department of Pathology Amsterdam Neuroscience VU University Medical Center Amsterdam The Netherlands
| | - Mohit Dubey
- Department of Pediatrics/Child Neurology Amsterdam Neuroscience VU University Medical Center Amsterdam The Netherlands.,Department of Integrative Neurophysiology Center for Neurogenomics and Cognitive Research Amsterdam Neuroscience VU University Amsterdam The Netherlands
| | - Marjolein Breur
- Department of Pediatrics/Child Neurology Amsterdam Neuroscience VU University Medical Center Amsterdam The Netherlands
| | - Nienke L Postma
- Department of Pediatrics/Child Neurology Amsterdam Neuroscience VU University Medical Center Amsterdam The Netherlands
| | - Marien P Dekker
- Department of Functional Genomics Center for Neurogenomics and Cognitive Research Amsterdam Neuroscience VU University Amsterdam The Netherlands
| | - Timo Ter Braak
- Department of Pediatrics/Child Neurology Amsterdam Neuroscience VU University Medical Center Amsterdam The Netherlands
| | - Ursula Boschert
- Translational Innovation Platform Immunology/Neurology EMD Serono Research & Development Institute Billerica 01821 Massachusetts
| | - Truus E M Abbink
- Department of Pediatrics/Child Neurology Amsterdam Neuroscience VU University Medical Center Amsterdam The Netherlands
| | - Huibert D Mansvelder
- Department of Integrative Neurophysiology Center for Neurogenomics and Cognitive Research Amsterdam Neuroscience VU University Amsterdam The Netherlands
| | - Rogier Min
- Department of Pediatrics/Child Neurology Amsterdam Neuroscience VU University Medical Center Amsterdam The Netherlands.,Department of Integrative Neurophysiology Center for Neurogenomics and Cognitive Research Amsterdam Neuroscience VU University Amsterdam The Netherlands
| | - Jan R T van Weering
- Department of Functional Genomics Center for Neurogenomics and Cognitive Research Amsterdam Neuroscience VU University Amsterdam The Netherlands
| | - Marjo S van der Knaap
- Department of Pediatrics/Child Neurology Amsterdam Neuroscience VU University Medical Center Amsterdam The Netherlands.,Department of Functional Genomics Center for Neurogenomics and Cognitive Research Amsterdam Neuroscience VU University Amsterdam The Netherlands
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27
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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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28
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Sugio S, Tohyama K, Oku S, Fujiyoshi K, Yoshimura T, Hikishima K, Yano R, Fukuda T, Nakamura M, Okano H, Watanabe M, Fukata M, Ikenaka K, Tanaka KF. Astrocyte-mediated infantile-onset leukoencephalopathy mouse model. Glia 2016; 65:150-168. [DOI: 10.1002/glia.23084] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 09/22/2016] [Accepted: 09/29/2016] [Indexed: 01/09/2023]
Affiliation(s)
- Shouta Sugio
- Division of Neurobiology and Bioinformatics; National Institute for Physiological Sciences; Okazaki 444-8787 Japan
- Department of Physiological Sciences, School of Life Science; SOKENDAI (The Graduate University for Advanced Studies); Okazaki 444-8787 Japan
| | - Koujiro Tohyama
- Department of Physiology School of Dentistry, The Center of EM and Bio-Imaging Research, Nano-Neuroanatomy; Iwate Medical University; Morioka 020-8505 Japan
| | - Shinichiro Oku
- Division of Membrane Physiology, National Institute for Physiological Sciences; Okazaki 444-8787 Japan
| | - Kanehiro Fujiyoshi
- Department of Orthopedic Surgery; Keio University School of Medicine; Tokyo 160-8582 Japan
- Department of Orthopedic Surgery; National Hospital Organization, Murayama Medical Center; Tokyo 208-0011 Japan
| | - Takeshi Yoshimura
- Division of Neurobiology and Bioinformatics; National Institute for Physiological Sciences; Okazaki 444-8787 Japan
- Department of Physiological Sciences, School of Life Science; SOKENDAI (The Graduate University for Advanced Studies); Okazaki 444-8787 Japan
| | - Keigo Hikishima
- Department of Physiology; Keio University School of Medicine; Tokyo 160-8582 Japan
- Central Institute for Experimental Animals; Kawasaki 210-0821 Japan
| | - Ryutaro Yano
- Department of Physiology; Keio University School of Medicine; Tokyo 160-8582 Japan
| | - Takahiro Fukuda
- Division of Neuropathology, Department of Pathology; The Jikei University School of Medicine; Tokyo 105-8461 Japan
| | - Masaya Nakamura
- Department of Orthopedic Surgery; Keio University School of Medicine; Tokyo 160-8582 Japan
| | - Hideyuki Okano
- Department of Physiology; Keio University School of Medicine; Tokyo 160-8582 Japan
| | - Masahiko Watanabe
- Department of Anatomy; Hokkaido University Graduate School of Medicine; Sapporo 060-8638 Japan
| | - Masaki Fukata
- Department of Physiological Sciences, School of Life Science; SOKENDAI (The Graduate University for Advanced Studies); Okazaki 444-8787 Japan
- Division of Membrane Physiology, National Institute for Physiological Sciences; Okazaki 444-8787 Japan
| | - Kazuhiro Ikenaka
- Division of Neurobiology and Bioinformatics; National Institute for Physiological Sciences; Okazaki 444-8787 Japan
- Department of Physiological Sciences, School of Life Science; SOKENDAI (The Graduate University for Advanced Studies); Okazaki 444-8787 Japan
| | - Kenji F. Tanaka
- Division of Neurobiology and Bioinformatics; National Institute for Physiological Sciences; Okazaki 444-8787 Japan
- Department of Neuropsychiatry; Keio University School of Medicine; Tokyo 160-8582 Japan
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29
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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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30
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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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Na+/K+-ATPase β1-subunit is recruited in Na-K-2Cl co-transporter isoform 2 multiprotein complexes in rat kidneys: possible role in blood pressure regulation. J Hypertens 2016; 32:1842-53. [PMID: 24927069 DOI: 10.1097/hjh.0000000000000258] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
OBJECTIVE The progression from prehypertensive to hypertensive state in spontaneous hypertensive rats (SHRs) is accompanied by a significant increase in membrane expression of Na-K-2Cl co-transporter isoform 2 (NKCC2), suggesting that the altered NKCC2 trafficking and activity are directly related with the development of hypertension in this strain. The aim of this work is to gain insights on the molecular mechanism that underlies this phenomenon. METHODS We performed a comparative analysis of NKCC2 multiprotein complexes (MPCs) in the kidney of SHRs versus Wistar Kyoto rats by Blue Native difference gel electrophoresis combined with mass spectrometry. RESULTS We found that the recruitment of the β-subunit isoform 1 of the Na(+)-K(+)-ATPase (β1NK) in NKCC2 MPCs was significantly increased in the kidneys of SHR compared with Wistar Kyoto rat control strain. Co-immunoprecipitation experiments showed that β1NK actually interacts with NKCC2 in the native tissue. The analysis of the physiological role of β1NK-NKCC2 interaction in human embryonic kidney cells showed that β1NK increased the steady-state membrane expression and activity of NKCC2 enhancing NKCC2 trafficking toward the plasma membrane. CONCLUSION We identify a new NKCC2-interacting partner involved in the modulation of NKCC2 intracellular trafficking and possibly involved in the regulation of blood pressure.
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32
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Capdevila-Nortes X, Jeworutzki E, Elorza-Vidal X, Barrallo-Gimeno A, Pusch M, Estévez R. Structural determinants of interaction, trafficking and function in the ClC-2/MLC1 subunit GlialCAM involved in leukodystrophy. J Physiol 2015; 593:4165-80. [PMID: 26033718 DOI: 10.1113/jp270467] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 05/22/2015] [Indexed: 02/03/2023] Open
Abstract
KEY POINTS The extracellular domain of GlialCAM is necessary for its targeting to cell junctions, as well as for interactions with itself and MLC1 and ClC-2. The C-terminus of GlialCAM is not necessary for interaction but is required for targeting to cell junctions. The first three residues of the transmembrane segment of GlialCAM are required for GlialCAM-mediated ClC-2 activation. ABSTRACT Mutations in the genes encoding the astrocytic protein MLC1, the cell adhesion molecule GlialCAM or the Cl(-) channel ClC-2 underlie human leukodystrophies. GlialCAM binds to itself, to MLC1 and to ClC-2, and directs these proteins to cell-cell contacts. In addition, GlialCAM dramatically activates ClC-2 mediated currents. In the present study, we used mutagenesis studies combined with functional and biochemical analyses to determine which parts of GlialCAM are required to perform these cellular functions. We found that the extracellular domain of GlialCAM is necessary for cell junction targeting and for mediating interactions with itself or with MLC1 and ClC-2. The C-terminus is also necessary for proper targeting to cell-cell junctions but is not required for the biochemical interaction. Finally, we identified the first three amino acids of the transmembrane segment of GlialCAM as being essential for the activation of ClC-2 currents but not for targeting or biochemical interaction. Our results provide new mechanistic insights concerning the regulation of the cell biology and function of MLC1 and ClC-2 by GlialCAM.
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Affiliation(s)
- Xavier Capdevila-Nortes
- Sección de Fisiología, Departamento de Ciencias Fisiológicas II, Universidad de Barcelona, Barcelona, Spain
| | - Elena Jeworutzki
- Istituto di Biofisica, CNR, Genoa, Italy.,Present address IfGH-Myocellular Electrophysiology, Department of Cardiovascular Medicine, University Hospital of Münster, Münster, Germany
| | - Xabier Elorza-Vidal
- Sección de Fisiología, Departamento de Ciencias Fisiológicas II, Universidad de Barcelona, Barcelona, Spain.,U-750, Centro de investigación en red de enfermedades raras (CIBERER), ISCIII, Barcelona, Spain
| | - Alejandro Barrallo-Gimeno
- Sección de Fisiología, Departamento de Ciencias Fisiológicas II, Universidad de Barcelona, Barcelona, Spain
| | | | - Raúl Estévez
- Sección de Fisiología, Departamento de Ciencias Fisiológicas II, Universidad de Barcelona, Barcelona, Spain.,U-750, Centro de investigación en red de enfermedades raras (CIBERER), ISCIII, Barcelona, Spain
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33
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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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Dubey M, Bugiani M, Ridder MC, Postma NL, Brouwers E, Polder E, Jacobs JG, Baayen JC, Klooster J, Kamermans M, Aardse R, de Kock CPJ, Dekker MP, van Weering JRT, Heine VM, Abbink TEM, Scheper GC, Boor I, Lodder JC, Mansvelder HD, van der Knaap MS. Mice with megalencephalic leukoencephalopathy with cysts: A developmental angle. Ann Neurol 2014; 77:114-31. [DOI: 10.1002/ana.24307] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 10/27/2014] [Accepted: 11/02/2014] [Indexed: 11/11/2022]
Affiliation(s)
- Mohit Dubey
- Department of Pediatrics/Child Neurology; Neuroscience Campus Amsterdam, VU University Medical Center
- Department of Integrative Neurophysiology; Center for Neurogenomics and Cognitive Research, VU University
| | - Marianna Bugiani
- Department of Pediatrics/Child Neurology; Neuroscience Campus Amsterdam, VU University Medical Center
- Department of Pathology; VU University Medical Center
| | - Margreet C. Ridder
- Department of Pediatrics/Child Neurology; Neuroscience Campus Amsterdam, VU University Medical Center
| | - Nienke L. Postma
- Department of Pediatrics/Child Neurology; Neuroscience Campus Amsterdam, VU University Medical Center
| | - Eelke Brouwers
- Department of Pediatrics/Child Neurology; Neuroscience Campus Amsterdam, VU University Medical Center
- Department of Integrative Neurophysiology; Center for Neurogenomics and Cognitive Research, VU University
| | - Emiel Polder
- Department of Pediatrics/Child Neurology; Neuroscience Campus Amsterdam, VU University Medical Center
| | - J. Gerbren Jacobs
- Department of Pediatrics/Child Neurology; Neuroscience Campus Amsterdam, VU University Medical Center
- Department of Functional Genomics; Center for Neurogenomics and Cognitive Research, VU University
| | | | - Jan Klooster
- Department of Retinal Signal Processing; Netherlands Institute for Neuroscience-KNAW; Amsterdam Netherlands
| | - Maarten Kamermans
- Department of Retinal Signal Processing; Netherlands Institute for Neuroscience-KNAW; Amsterdam Netherlands
| | - Romy Aardse
- Department of Integrative Neurophysiology; Center for Neurogenomics and Cognitive Research, VU University
| | - Christiaan P. J. de Kock
- Department of Integrative Neurophysiology; Center for Neurogenomics and Cognitive Research, VU University
| | - Marien P. Dekker
- Department of Functional Genomics; Center for Neurogenomics and Cognitive Research, VU University
| | - Jan R. T. van Weering
- Department of Functional Genomics; Center for Neurogenomics and Cognitive Research, VU University
| | - Vivi M. Heine
- Department of Pediatrics/Child Neurology; Neuroscience Campus Amsterdam, VU University Medical Center
- Department of Functional Genomics; Center for Neurogenomics and Cognitive Research, VU University
| | - Truus E. M. Abbink
- Department of Pediatrics/Child Neurology; Neuroscience Campus Amsterdam, VU University Medical Center
| | - Gert C. Scheper
- Department of Pediatrics/Child Neurology; Neuroscience Campus Amsterdam, VU University Medical Center
| | - Ilja Boor
- Department of Pediatrics/Child Neurology; Neuroscience Campus Amsterdam, VU University Medical Center
| | - Johannes C. Lodder
- Department of Integrative Neurophysiology; Center for Neurogenomics and Cognitive Research, VU University
| | - Huibert D. Mansvelder
- Department of Integrative Neurophysiology; Center for Neurogenomics and Cognitive Research, VU University
| | - Marjo S. van der Knaap
- Department of Pediatrics/Child Neurology; Neuroscience Campus Amsterdam, VU University Medical Center
- Department of Functional Genomics; Center for Neurogenomics and Cognitive Research, VU University
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Brignone MS, Lanciotti A, Visentin S, De Nuccio C, Molinari P, Camerini S, Diociaiuti M, Petrini S, Minnone G, Crescenzi M, Laudiero LB, Bertini E, Petrucci TC, Ambrosini E. Megalencephalic leukoencephalopathy with subcortical cysts protein-1 modulates endosomal pH and protein trafficking in astrocytes: relevance to MLC disease pathogenesis. Neurobiol Dis 2014; 66:1-18. [PMID: 24561067 PMCID: PMC4003525 DOI: 10.1016/j.nbd.2014.02.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 01/20/2014] [Accepted: 02/10/2014] [Indexed: 11/28/2022] Open
Abstract
Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a rare leukodystrophy caused by mutations in the gene encoding MLC1, a membrane protein mainly expressed in astrocytes in the central nervous system. Although MLC1 function is unknown, evidence is emerging that it may regulate ion fluxes. Using biochemical and proteomic approaches to identify MLC1 interactors and elucidate MLC1 function we found that MLC1 interacts with the vacuolar ATPase (V-ATPase), the proton pump that regulates endosomal acidity. Because we previously showed that in intracellular organelles MLC1 directly binds Na, K-ATPase, which controls endosomal pH, we studied MLC1 endosomal localization and trafficking and MLC1 effects on endosomal acidity and function using human astrocytoma cells overexpressing wild-type (WT) MLC1 or MLC1 carrying pathological mutations. We found that WT MLC1 is abundantly expressed in early (EEA1(+), Rab5(+)) and recycling (Rab11(+)) endosomes and uses the latter compartment to traffic to the plasma membrane during hyposmotic stress. We also showed that WT MLC1 limits early endosomal acidification and influences protein trafficking in astrocytoma cells by stimulating protein recycling, as revealed by FITC-dextran measurement of endosomal pH and transferrin protein recycling assay, respectively. WT MLC1 also favors recycling to the plasma-membrane of the TRPV4 cation channel which cooperates with MLC1 to activate calcium influx in astrocytes during hyposmotic stress. Although MLC disease-causing mutations differentially affect MLC1 localization and trafficking, all the mutated proteins fail to influence endosomal pH and protein recycling. This study demonstrates that MLC1 modulates endosomal pH and protein trafficking suggesting that alteration of these processes contributes to MLC pathogenesis.
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Affiliation(s)
- Maria S Brignone
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Angela Lanciotti
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Sergio Visentin
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Chiara De Nuccio
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Paola Molinari
- Department of Pharmacology, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Serena Camerini
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Marco Diociaiuti
- Department of Technology and Health, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Stefania Petrini
- Unit of Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesù Pediatric Research Hospital, Piazza S. Onofrio 4, 00165 Rome, Italy.
| | - Gaetana Minnone
- Unit of Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesù Pediatric Research Hospital, Piazza S. Onofrio 4, 00165 Rome, Italy.
| | - Marco Crescenzi
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Luisa Bracci Laudiero
- Unit of Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesù Pediatric Research Hospital, Piazza S. Onofrio 4, 00165 Rome, Italy; Institute of Translational Pharmacology, CNR, Via del Fosso Cavaliere 100, 00133 Rome, Italy.
| | - Enrico Bertini
- Unit of Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesù Pediatric Research Hospital, Piazza S. Onofrio 4, 00165 Rome, Italy.
| | - Tamara C Petrucci
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Elena Ambrosini
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
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36
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Sirisi S, Folgueira M, López-Hernández T, Minieri L, Pérez-Rius C, Gaitán-Peñas H, Zang J, Martínez A, Capdevila-Nortes X, De La Villa P, Roy U, Alia A, Neuhauss S, Ferroni S, Nunes V, Estévez R, Barrallo-Gimeno A. Megalencephalic leukoencephalopathy with subcortical cysts protein 1 regulates glial surface localization of GLIALCAM from fish to humans. Hum Mol Genet 2014; 23:5069-86. [DOI: 10.1093/hmg/ddu231] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Ambrosini E, Sicca F, Brignone MS, D'Adamo MC, Napolitano C, Servettini I, Moro F, Ruan Y, Guglielmi L, Pieroni S, Servillo G, Lanciotti A, Valvo G, Catacuzzeno L, Franciolini F, Molinari P, Marchese M, Grottesi A, Guerrini R, Santorelli FM, Priori S, Pessia M. Genetically induced dysfunctions of Kir2.1 channels: implications for short QT3 syndrome and autism-epilepsy phenotype. Hum Mol Genet 2014; 23:4875-86. [PMID: 24794859 PMCID: PMC4140467 DOI: 10.1093/hmg/ddu201] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Short QT3 syndrome (SQT3S) is a cardiac disorder characterized by a high risk of mortality and associated with mutations in Kir2.1 (KCNJ2) channels. The molecular mechanisms leading to channel dysfunction, cardiac rhythm disturbances and neurodevelopmental disorders, potentially associated with SQT3S, remain incompletely understood. Here, we report on monozygotic twins displaying a short QT interval on electrocardiogram recordings and autism-epilepsy phenotype. Genetic screening identified a novel KCNJ2 variant in Kir2.1 that (i) enhanced the channel's surface expression and stability at the plasma membrane, (ii) reduced protein ubiquitylation and degradation, (iii) altered protein compartmentalization in lipid rafts by targeting more channels to cholesterol-poor domains and (iv) reduced interactions with caveolin 2. Importantly, our study reveals novel physiological mechanisms concerning wild-type Kir2.1 channel processing by the cell, such as binding to both caveolin 1 and 2, protein degradation through the ubiquitin-proteasome pathway; in addition, it uncovers a potential multifunctional site that controls Kir2.1 surface expression, protein half-life and partitioning to lipid rafts. The reported mechanisms emerge as crucial also for proper astrocyte function, suggesting the need for a neuropsychiatric evaluation in patients with SQT3S and offering new opportunities for disease management.
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Affiliation(s)
- Elena Ambrosini
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome 00161, Italy,
| | - Federico Sicca
- Clinical Neurophysiology Laboratory, Department of Developmental Neuroscience and
| | - Maria S Brignone
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome 00161, Italy
| | - Maria C D'Adamo
- Faculty of Medicine, Section of Physiology & Biochemistry, Department of Experimental Medicine
| | - Carlo Napolitano
- Molecular Cardiology, IRCCS Salvatore Maugeri Foundation, Pavia, Italy
| | - Ilenio Servettini
- Faculty of Medicine, Section of Physiology & Biochemistry, Department of Experimental Medicine
| | - Francesca Moro
- Clinical Neurophysiology Laboratory, Department of Developmental Neuroscience and
| | - Yanfei Ruan
- Molecular Cardiology, IRCCS Salvatore Maugeri Foundation, Pavia, Italy
| | - Luca Guglielmi
- Faculty of Medicine, Section of Physiology & Biochemistry, Department of Experimental Medicine
| | | | | | - Angela Lanciotti
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome 00161, Italy
| | - Giulia Valvo
- Clinical Neurophysiology Laboratory, Department of Developmental Neuroscience and
| | - Luigi Catacuzzeno
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Perugia, Italy
| | - Fabio Franciolini
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Perugia, Italy
| | - Paola Molinari
- Department of Pharmacology, Istituto Superiore di Sanità, Rome, Italy
| | - Maria Marchese
- Molecular Medicine Laboratory, IRCCS Stella Maris Foundation, Pisa, Italy
| | | | - Renzo Guerrini
- Clinical Neurophysiology Laboratory, Department of Developmental Neuroscience and Pediatric Neurology Unit and Laboratories, Children's Hospital A. Meyer-University of Florence, Florence, Italy
| | | | - Silvia Priori
- Molecular Cardiology, IRCCS Salvatore Maugeri Foundation, Pavia, Italy
| | - Mauro Pessia
- Faculty of Medicine, Section of Physiology & Biochemistry, Department of Experimental Medicine
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38
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Marchese M, Conti V, Valvo G, Moro F, Muratori F, Tancredi R, Santorelli FM, Guerrini R, Sicca F. Autism-epilepsy phenotype with macrocephaly suggests PTEN, but not GLIALCAM, genetic screening. BMC MEDICAL GENETICS 2014; 15:26. [PMID: 24580998 PMCID: PMC3941568 DOI: 10.1186/1471-2350-15-26] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2013] [Accepted: 02/21/2014] [Indexed: 01/27/2023]
Abstract
BACKGROUND With a complex and extremely high clinical and genetic heterogeneity, autism spectrum disorders (ASD) are better dissected if one takes into account specific endophenotypes. Comorbidity of ASD with epilepsy (or paroxysmal EEG) has long been described and seems to have strong genetic background. Macrocephaly also represents a well-known endophenotype in subgroups of ASD individuals, which suggests pathogenic mechanisms accelerating brain growth in early development and predisposing to the disorder. We attempted to estimate the association of gene variants with neurodevelopmental disorders in patients with autism-epilepsy phenotype (AEP) and cranial overgrowth, analyzing two genes previously reported to be associated with autism and macrocephaly. METHODS We analyzed the coding sequences and exon-intron boundaries of GLIALCAM, encoding an IgG-like cell adhesion protein, in 81 individuals with Autism Spectrum Disorders, either with or without comorbid epilepsy, paroxysmal EEG and/or macrocephaly, and the PTEN gene in the subsample with macrocephaly. RESULTS Among 81 individuals with ASD, 31 had concurrent macrocephaly. Head circumference, moreover, was over the 99.7th percentile ("extreme" macrocephaly) in 6/31 (19%) patients. Whilst we detected in GLIALCAM several single nucleotide variants without clear pathogenic effects, we found a novel PTEN heterozygous frameshift mutation in one case with "extreme" macrocephaly, autism, intellectual disability and seizures. CONCLUSIONS We did not find a clear association between GLIALCAM mutations and AEP-macrocephaly comorbidity. The identification of a novel frameshift variant of PTEN in a patient with "extreme" macrocephaly, autism, intellectual disability and seizures, confirms this gene as a major candidate in the ASD-macrocephaly endophenotype. The concurrence of epilepsy in the same patient also suggests that PTEN, and the downstream signaling pathway, might deserve to be investigated in autism-epilepsy comorbidity. Working on clinical endophenotypes might be of help to address genetic studies and establish actual causative correlations in autism-epilepsy.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Federico Sicca
- Clinical Neurophysiology Laboratory, IRCCS Stella Maris Foundation, Viale del Tirreno 331, Pisa, Calambrone 56128, Italy.
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Bi MM, Hong S, Zhou HY, Wang HW, Wang LN, Zheng YJ. Chloride channelopathies of ClC-2. Int J Mol Sci 2013; 15:218-49. [PMID: 24378849 PMCID: PMC3907807 DOI: 10.3390/ijms15010218] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Revised: 11/14/2013] [Accepted: 12/16/2013] [Indexed: 12/15/2022] Open
Abstract
Chloride channels (ClCs) have gained worldwide interest because of their molecular diversity, widespread distribution in mammalian tissues and organs, and their link to various human diseases. Nine different ClCs have been molecularly identified and functionally characterized in mammals. ClC-2 is one of nine mammalian members of the ClC family. It possesses unique biophysical characteristics, pharmacological properties, and molecular features that distinguish it from other ClC family members. ClC-2 has wide organ/tissue distribution and is ubiquitously expressed. Published studies consistently point to a high degree of conservation of ClC-2 function and regulation across various species from nematodes to humans over vast evolutionary time spans. ClC-2 has been intensively and extensively studied over the past two decades, leading to the accumulation of a plethora of information to advance our understanding of its pathophysiological functions; however, many controversies still exist. It is necessary to analyze the research findings, and integrate different views to have a better understanding of ClC-2. This review focuses on ClC-2 only, providing an analytical overview of the available literature. Nearly every aspect of ClC-2 is discussed in the review: molecular features, biophysical characteristics, pharmacological properties, cellular function, regulation of expression and function, and channelopathies.
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Affiliation(s)
- Miao Miao Bi
- Department of Ophthalmology, the Second Hospital of Jilin University, Jilin University, Changchun 130041, Jilin, China.
| | - Sen Hong
- Department of Ophthalmology, the Second Hospital of Jilin University, Jilin University, Changchun 130041, Jilin, China.
| | - Hong Yan Zhou
- Department of Ophthalmology, the Second Hospital of Jilin University, Jilin University, Changchun 130041, Jilin, China.
| | - Hong Wei Wang
- Department of Ophthalmology, the Second Hospital of Jilin University, Jilin University, Changchun 130041, Jilin, China.
| | - Li Na Wang
- Department of Ophthalmology, the Second Hospital of Jilin University, Jilin University, Changchun 130041, Jilin, China.
| | - Ya Juan Zheng
- Department of Ophthalmology, the Second Hospital of Jilin University, Jilin University, Changchun 130041, Jilin, China.
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40
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Petrini S, Minnone G, Coccetti M, Frank C, Aiello C, Cutarelli A, Ambrosini E, Lanciotti A, Brignone MS, D'Oria V, Strippoli R, De Benedetti F, Bertini E, Bracci-Laudiero L. Monocytes and macrophages as biomarkers for the diagnosis of megalencephalic leukoencephalopathy with subcortical cysts. Mol Cell Neurosci 2013; 56:307-21. [DOI: 10.1016/j.mcn.2013.07.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Revised: 06/05/2013] [Accepted: 07/02/2013] [Indexed: 12/20/2022] Open
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41
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Capdevila-Nortes X, López-Hernández T, Apaja PM, López de Heredia M, Sirisi S, Callejo G, Arnedo T, Nunes V, Lukacs GL, Gasull X, Estévez R. Insights into MLC pathogenesis: GlialCAM is an MLC1 chaperone required for proper activation of volume-regulated anion currents. Hum Mol Genet 2013; 22:4405-16. [DOI: 10.1093/hmg/ddt290] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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42
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Abstract
Astrocytes are the predominant glial cell population in the central nervous system (CNS). Once considered only passive scaffolding elements, astrocytes are now recognised as cells playing essential roles in CNS development and function. They control extracellular water and ion homeostasis, provide substrates for energy metabolism, and regulate neurogenesis, myelination and synaptic transmission. Due to these multiple activities astrocytes have been implicated in almost all brain pathologies, contributing to various aspects of disease initiation, progression and resolution. Evidence is emerging that astrocyte dysfunction can be the direct cause of neurodegeneration, as shown in Alexander's disease where myelin degeneration is caused by mutations in the gene encoding the astrocyte-specific cytoskeleton protein glial fibrillary acidic protein. Recent studies point to a primary role for astrocytes in the pathogenesis of other genetic leukodystrophies such as megalencephalic leukoencephalopathy with subcortical cysts and vanishing white matter disease. The aim of this review is to summarize current knowledge of the pathophysiological role of astrocytes focusing on their contribution to the development of the above mentioned leukodystrophies and on new perspectives for the treatment of neurological disorders.
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van der Knaap MS, Boor I, Estévez R. Megalencephalic leukoencephalopathy with subcortical cysts: chronic white matter oedema due to a defect in brain ion and water homoeostasis. Lancet Neurol 2012; 11:973-85. [PMID: 23079554 DOI: 10.1016/s1474-4422(12)70192-8] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is characterised by chronic white matter oedema. The disease has an infantile onset and leads to slow neurological deterioration in most cases, but, surprisingly, some patients recover. The first disease gene, MLC1, identified in 2001, is mutated in 75% of patients. At that time, nothing was known about MLC1 protein function and the pathophysiology of MLC. More recently, HEPACAM (also called GLIALCAM) has been identified as a second disease gene. GlialCAM serves as an escort for MLC1 and the chloride channel CLC2. The defect in MLC1 has been shown to hamper the cell volume regulation of astrocytes. One of the most important consequences involves the potassium siphoning process, which is essential in brain ion and water homoeostasis. An understanding of the mechanisms of white matter oedema in MLC is emerging. Further insight into the specific function of MLC1 is necessary to find treatment targets.
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Affiliation(s)
- Marjo S van der Knaap
- Department of Pediatrics/Child Neurology, VU University Medical Centre, Amsterdam, Netherlands.
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44
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Jeworutzki E, López-Hernández T, Capdevila-Nortes X, Sirisi S, Bengtsson L, Montolio M, Zifarelli G, Arnedo T, Müller CS, Schulte U, Nunes V, Martínez A, Jentsch TJ, Gasull X, Pusch M, Estévez R. GlialCAM, a protein defective in a leukodystrophy, serves as a ClC-2 Cl(-) channel auxiliary subunit. Neuron 2012; 73:951-61. [PMID: 22405205 PMCID: PMC3334819 DOI: 10.1016/j.neuron.2011.12.039] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/23/2011] [Indexed: 11/30/2022]
Abstract
Ion fluxes mediated by glial cells are required for several physiological processes such as fluid homeostasis or the maintenance of low extracellular potassium during high neuronal activity. In mice, the disruption of the Cl− channel ClC-2 causes fluid accumulation leading to myelin vacuolation. A similar vacuolation phenotype is detected in humans affected with megalencephalic leukoencephalopathy with subcortical cysts (MLC), a leukodystrophy which is caused by mutations in MLC1 or GLIALCAM. We here identify GlialCAM as a ClC-2 binding partner. GlialCAM and ClC-2 colocalize in Bergmann glia, in astrocyte-astrocyte junctions at astrocytic endfeet around blood vessels, and in myelinated fiber tracts. GlialCAM targets ClC-2 to cell junctions, increases ClC-2 mediated currents, and changes its functional properties. Disease-causing GLIALCAM mutations abolish the targeting of the channel to cell junctions. This work describes the first auxiliary subunit of ClC-2 and suggests that ClC-2 may play a role in the pathology of MLC disease. Video Abstract
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Affiliation(s)
- Elena Jeworutzki
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, 16149 Genoa, Italy
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Maduke MC, Reimer RJ. Biochemistry to the rescue: a ClC-2 auxiliary subunit provides a tangible link to leukodystrophy. Neuron 2012; 73:855-7. [PMID: 22405196 DOI: 10.1016/j.neuron.2012.02.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
ClC-2 is a broadly distributed chloride channel with an enigmatic neurophysiological function. In this issue of Neuron, Jeworutzki et al. (2012) use a biochemical approach to identify GlialCAM, a protein with a defined link to leukodystrophy, as a ClC-2 auxiliary subunit.
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Affiliation(s)
- Merritt C Maduke
- Department of Molecular and Cellular Physiology, Stanford University, 279 Campus Drive West, Stanford, CA 94305, USA.
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Lanciotti A, Brignone MS, Molinari P, Visentin S, De Nuccio C, Macchia G, Aiello C, Bertini E, Aloisi F, Petrucci TC, Ambrosini E. Megalencephalic leukoencephalopathy with subcortical cysts protein 1 functionally cooperates with the TRPV4 cation channel to activate the response of astrocytes to osmotic stress: dysregulation by pathological mutations. Hum Mol Genet 2012; 21:2166-80. [PMID: 22328087 DOI: 10.1093/hmg/dds032] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Megalencephalic leukoencephalopathy with subcortical cysts (MLC), a rare leukodystrophy characterized by macrocephaly, subcortical fluid cysts and myelin vacuolation, has been linked to mutations in the MLC1 gene. This gene encodes a membrane protein that is highly expressed in astrocytes. Based on MLC pathological features, it was proposed that astrocyte-mediated defects in ion and fluid homeostasis could account for the alterations observed in MLC-affected brains. However, the role of MLC1 and the effects of pathological mutations on astrocyte osmoregulatory functions have still to be demonstrated. Using human astrocytoma cells stably overexpressing wild-type MLC1 or three known MLC-associated pathological mutations, we investigated MLC1 involvement in astrocyte reaction to osmotic changes using biochemical, dynamic video imaging and immunofluorescence techniques. We have found that MLC1 overexpressed in astrocytoma cells is mainly localized in the plasma membrane, is part of the Na,K-ATPase-associated molecular complex that includes the potassium channel Kir4.1, syntrophin and aquaporin-4 and functionally interacts with the calcium permeable channel TRPV4 (transient receptor potential vanilloid-4 cation channel) which mediates swelling-induced cytosolic calcium increase and volume recovery in response to hyposmosis. Pathological MLC mutations cause changes in MLC1 expression and intracellular localization as well as in the astrocyte response to osmotic changes by altering MLC1 molecular interactions with the Na,K-ATPase molecular complex and abolishing the increase in calcium influx induced by hyposmosis and treatment with the TRPV4 agonist 4αPDD. These data demonstrate, for the first time, that MLC1 plays a role in astrocyte osmo-homeostasis and that defects in intracellular calcium dynamics may contribute to MLC pathogenesis.
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Affiliation(s)
- Angela Lanciotti
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità,Viale Regina Elena 299, Rome 00161, Italy
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Eilert-Olsen M, Haj-Yasein NN, Vindedal GF, Enger R, Gundersen GA, Hoddevik EH, Petersen PH, Haug FMS, Skare Ø, Adams ME, Froehner SC, Burkhardt JM, Thoren AE, Nagelhus EA. Deletion of aquaporin-4 changes the perivascular glial protein scaffold without disrupting the brain endothelial barrier. Glia 2011; 60:432-40. [PMID: 22131281 DOI: 10.1002/glia.22277] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2010] [Accepted: 11/11/2011] [Indexed: 11/08/2022]
Abstract
Expression of the water channel aquaporin-4 (AQP4) at the blood-brain interface is dependent upon the dystrophin associated protein complex. Here we investigated whether deletion of the Aqp4 gene affects the molecular composition of this protein scaffold and the integrity of the blood-brain barrier. High-resolution immunogold cytochemistry revealed that perivascular expression of α-syntrophin was reduced by 60% in Aqp4(-/-) mice. Additionally, perivascular AQP4 expression was reduced by 88% in α-syn(-/-) mice, in accordance with earlier reports. Immunofluorescence showed that Aqp4 deletion also caused a modest reduction in perivascular dystrophin, whereas β-dystroglycan labeling was unaltered. Perivascular microglia were devoid of AQP4 immunoreactivity. Deletion of Aqp4 did not alter the ultrastructure of capillary endothelial cells, the expression of tight junction proteins (claudin-5, occludin, and zonula occludens 1), or the vascular permeability to horseradish peroxidase and Evans blue albumin dye. We conclude that Aqp4 deletion reduces the expression of perivascular glial scaffolding proteins without affecting the endothelial barrier. Our data also indicate that AQP4 and α-syntrophin are mutually dependent upon each other for proper perivascular expression.
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Affiliation(s)
- Martine Eilert-Olsen
- Centre for Molecular Medicine Norway, Nordic EMBL Partnership, University of Oslo, 0318 Oslo, Norway
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López-Hernández T, Sirisi S, Capdevila-Nortes X, Montolio M, Fernández-Dueñas V, Scheper GC, van der Knaap MS, Casquero P, Ciruela F, Ferrer I, Nunes V, Estévez R. Molecular mechanisms of MLC1 and GLIALCAM mutations in megalencephalic leukoencephalopathy with subcortical cysts. Hum Mol Genet 2011; 20:3266-77. [DOI: 10.1093/hmg/ddr238] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Mutant GlialCAM causes megalencephalic leukoencephalopathy with subcortical cysts, benign familial macrocephaly, and macrocephaly with retardation and autism. Am J Hum Genet 2011; 88:422-32. [PMID: 21419380 DOI: 10.1016/j.ajhg.2011.02.009] [Citation(s) in RCA: 127] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Revised: 01/12/2011] [Accepted: 02/21/2011] [Indexed: 11/23/2022] Open
Abstract
Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a leukodystrophy characterized by early-onset macrocephaly and delayed-onset neurological deterioration. Recessive MLC1 mutations are observed in 75% of patients with MLC. Genetic-linkage studies failed to identify another gene. We recently showed that some patients without MLC1 mutations display the classical phenotype; others improve or become normal but retain macrocephaly. To find another MLC-related gene, we used quantitative proteomic analysis of affinity-purified MLC1 as an alternative approach and found that GlialCAM, an IgG-like cell adhesion molecule that is also called HepaCAM and is encoded by HEPACAM, is a direct MLC1-binding partner. Analysis of 40 MLC patients without MLC1 mutations revealed multiple different HEPACAM mutations. Ten patients with the classical, deteriorating phenotype had two mutations, and 18 patients with the improving phenotype had one mutation. Most parents with a single mutation had macrocephaly, indicating dominant inheritance. In some families with dominant HEPACAM mutations, the clinical picture and magnetic resonance imaging normalized, indicating that HEPACAM mutations can cause benign familial macrocephaly. In other families with dominant HEPACAM mutations, patients had macrocephaly and mental retardation with or without autism. Further experiments demonstrated that GlialCAM and MLC1 both localize in axons and colocalize in junctions between astrocytes. GlialCAM is additionally located in myelin. Mutant GlialCAM disrupts the localization of MLC1-GlialCAM complexes in astrocytic junctions in a manner reflecting the mode of inheritance. In conclusion, GlialCAM is required for proper localization of MLC1. HEPACAM is the second gene found to be mutated in MLC. Dominant HEPACAM mutations can cause either macrocephaly and mental retardation with or without autism or benign familial macrocephaly.
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