title: Dynamics of membrane lipid domains in neuronal cells differentiated in culture.
abstract: Treatment with methyl-beta-cyclodextrin (MCD) induced a time- and dose-dependent efflux of cholesterol, sphingolipids, and phosphatidylcholine (PC) from cerebellar neurons differentiated in culture. With a "mild" treatment, the loss of cell lipids induced a deep reorganization of the remaining membrane lipids. In fact, the amount of PC associated with a Triton X-100-insoluble membrane fraction (highly enriched in sphingolipids and cholesterol in nontreated cells) was lowered by the treatment. This suggested a reduction of the lipid domain area. However, the cholesterol and sphingolipid enrichment of this fraction remained substantially unchanged, suggesting the existence of dynamic processes aimed at preserving the segregation of cholesterol and sphingolipids in membrane domains. Under these conditions, the lipid membrane domains retained the ability to sort signaling proteins, such as Lyn and c-Src, but cells displayed deep alterations in their membrane permeability. However, normal membrane permeability was restored by loading cells with cholesterol. When MCD treatment was more stringent, a large loss of cell lipids occurred, and the lipid domains were much less enriched in cholesterol and lost the ability to sort specific proteins. The loss of the integrity and properties of lipid domains was accompanied by severe changes in the membrane permeability, distress, and eventually cell death.
authors.affiliation: Department of Medical Chemistry, Biochemistry, and Biotechnology, Center of Excellence on Neurodegenerative Diseases, University of Milan, Segrate, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Ottico
authors.forename: Alessandro
authors.initials: A
authors.lastname: Prinetti
authors.forename: Simona
authors.initials: S
authors.lastname: Prioni
authors.forename: Claudia
authors.initials: C
authors.lastname: Giannotta
authors.forename: Luisa
authors.initials: L
authors.lastname: Basso
authors.forename: Vanna
authors.initials: V
authors.lastname: Chigorno
authors.forename: Sandro
authors.initials: S
authors.lastname: Sonnino
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology; D002784:Cholesterol / Q000378:metabolism; D003505:Cyclodextrins / Q000494:pharmacology; D020404:Glycerophospholipids / Q000378:metabolism; D006028:Glycosphingolipids / Q000378:metabolism; D009474:Neurons / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D010713:Phosphatidylcholines / Q000378:metabolism*; D021381:Protein Transport / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D047392:beta-Cyclodextrins
chemical_list: D003505:Cyclodextrins; D020404:Glycerophospholipids; D006028:Glycosphingolipids; D010713:Phosphatidylcholines; D047392:beta-Cyclodextrins; C108732:methyl-beta-cyclodextrin; D002784:Cholesterol