title: Knockdown of MLC1 in primary astrocytes causes cell vacuolation: a MLC disease cell model.
abstract: Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a rare type of leukodystrophy, in the majority of cases caused by mutations in the MLC1 gene. MRI from MLC patients shows diffuse cerebral white matter signal abnormality and swelling, with evidence of increased water content. Histopathology in a MLC patient shows vacuolation of myelin, which causes the cerebral white matter swelling. MLC1 protein is expressed in astrocytic processes that are part of blood- and cerebrospinal fluid-brain barriers. We aimed to create an astrocyte cell model of MLC disease. The characterization of rat astrocyte cultures revealed MLC1 localization in cell-cell contacts, which contains other proteins described typically in tight and adherent junctions. MLC1 localization in these contacts was demonstrated to depend on the actin cytoskeleton; it was not altered when disrupting the microtubule or the GFAP networks. In human tissues, MLC1 and the protein Zonula Occludens 1 (ZO-1), which is linked to the actin cytoskeleton, co-localized by EM immunostaining and were specifically co-immunoprecipitated. To create an MLC cell model, knockdown of MLC1 in primary astrocytes was performed. Reduction of MLC1 expression resulted in the appearance of intracellular vacuoles. This vacuolation was reversed by the co-expression of human MLC1. Re-examination of a human brain biopsy from an MLC patient revealed that vacuoles were also consistently present in astrocytic processes. Thus, vacuolation of astrocytes is also a hallmark of MLC disease.
authors: Sección de Fisiología, Departamento de Ciencias Fisiológicas II, Universidad de Barcelona, Spain.
authors: Anna
authors: A
authors: Duarri
authors: Miguel
authors: M
authors: Lopez de Heredia
authors: Xavier
authors: X
authors: Capdevila-Nortes
authors: Margreet C
authors: MC
authors: Ridder
authors: Marisol
authors: M
authors: Montolio
authors: Tania
authors: T
authors: López-Hernández
authors: Ilja
authors: I
authors: Boor
authors: Chun-Fu
authors: CF
authors: Lien
authors: Tracy
authors: T
authors: Hagemann
authors: Albee
authors: A
authors: Messing
authors: Dariusz C
authors: DC
authors: Gorecki
authors: Gert C
authors: GC
authors: Scheper
authors: Albert
authors: A
authors: Martínez
authors: Virginia
authors: V
authors: Nunes
authors: Marjo S
authors: MS
authors: van der Knaap
authors: Raúl
authors: R
authors: Estévez
mesh_terms: D000293:Adolescent; D000818:Animals; D001253:Astrocytes / Q000378:metabolism* / Q000473:pathology; D002478:Cells, Cultured; D003560:Cysts / Q000235:genetics* / Q000378:metabolism* / Q000503:physiopathology; D015536:Down-Regulation / Q000235:genetics; D045604:Extracellular Fluid / Q000378:metabolism; D020279:Hereditary Central Nervous System Demyelinating Diseases / Q000235:genetics* / Q000378:metabolism* / Q000503:physiopathology; D006801:Humans; D008565:Membrane Proteins / Q000172:deficiency* / Q000235:genetics* / Q000502:physiology; D051379:Mice; D051381:Rats; D017207:Rats, Sprague-Dawley; D014617:Vacuoles / Q000235:genetics* / Q000473:pathology
chemical_list: C425069:MLC1 protein, human; D008565:Membrane Proteins