title: Plasma membrane production of ceramide from ganglioside GM3 in human fibroblasts.
abstract: Ceramide is a key lipid molecule necessary to regulate some cellular processes, including apoptosis and cell differentiation. In this context, its production has been shown to occur via sphingomyelin hydrolysis or sphingosine acylation. Here, we show that in human fibroblasts, plasma membrane ceramide is also produced from ganglioside GM3 by detachment of sugar units. Membrane-bound glycosylhydrolases have a role in this process. In fact, the production of ceramide from GM3 has been observed even under experimental conditions able to block endocytosis or lysosomal activity, and the overexpression of the plasma membrane ganglioside sialidase Neu3 corresponded to a higher production of ceramide in the plasma membrane. The increased activity of Neu3 was paralleled by an increase of GM3 synthase mRNA and GM3 synthase activity. Neu3-overexpressing fibroblasts were characterized by a reduced proliferation rate and higher basal number of apoptotic cells in comparison with wild-type cells. A similar behavior was observed when normal fibroblasts were treated with exogenous C2-ceramide.
authors.affiliation: Department of Medical Chemistry, Biochemistry and Biotechnology and Center of Excellence on Neurodegenerative Diseases, University of Milan, Via Fratelli Cervi 93, Segrate 20090, Milan, Italy.
authors.forename: Rea
authors.initials: R
authors.lastname: Valaperta
authors.forename: Vanna
authors.initials: V
authors.lastname: Chigorno
authors.forename: Luisa
authors.initials: L
authors.lastname: Basso
authors.forename: Alessandro
authors.initials: A
authors.lastname: Prinetti
authors.forename: Roberto
authors.initials: R
authors.lastname: Bresciani
authors.forename: Augusto
authors.initials: A
authors.lastname: Preti
authors.forename: Taeko
authors.initials: T
authors.lastname: Miyagi
authors.forename: Sandro
authors.initials: S
authors.lastname: Sonnino
mesh_terms: D000818:Animals; D017209:Apoptosis; D002462:Cell Membrane / Q000201:enzymology*; D002478:Cells, Cultured; D002518:Ceramides / Q000378:metabolism*; D005347:Fibroblasts / Q000166:cytology / Q000201:enzymology*; D005679:G(M3) Ganglioside / Q000378:metabolism*; D006801:Humans; D051379:Mice; D009439:Neuraminidase / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D013107:Sphingolipids / Q000737:chemistry
chemical_list: D002518:Ceramides; D005679:G(M3) Ganglioside; D012333:RNA, Messenger; D013107:Sphingolipids; C465436:Neu3 protein, human; C511796:Neu3 protein, mouse; D009439:Neuraminidase