title: Differential uPAR recruitment in caveolar-lipid rafts by GM1 and GM3 gangliosides regulates endothelial progenitor cells angiogenesis.
abstract: Gangliosides and the urokinase plasminogen activator receptor (uPAR) tipically partition in specialized membrane microdomains called lipid-rafts. uPAR becomes functionally important in fostering angiogenesis in endothelial progenitor cells (EPCs) upon recruitment in caveolar-lipid rafts. Moreover, cell membrane enrichment with exogenous GM1 ganglioside is pro-angiogenic and opposite to the activity of GM3 ganglioside. On these basis, we first checked the interaction of uPAR with membrane models enriched with GM1 or GM3, relying on the adoption of solid-supported mobile bilayer lipid membranes with raft-like composition formed onto solid hydrophilic surfaces, and evaluated by surface plasmon resonance (SPR) the extent of uPAR recruitment. We estimated the apparent dissociation constants of uPAR-GM1/GM3 complexes. These preliminary observations, indicating that uPAR binds preferentially to GM1-enriched biomimetic membranes, were validated by identifying a pro-angiogenic activity of GM1-enriched EPCs, based on GM1-dependent uPAR recruitment in caveolar rafts. We have observed that addition of GM1 to EPCs culture medium promotes matrigel invasion and capillary morphogenesis, as opposed to the anti-angiogenesis activity of GM3. Moreover, GM1 also stimulates MAPKinases signalling pathways, typically associated with an angiogenesis program. Caveolar-raft isolation and Western blotting of uPAR showed that GM1 promotes caveolar-raft partitioning of uPAR, as opposed to control and GM3-challenged EPCs. By confocal microscopy, we have shown that in EPCs uPAR is present on the surface in at least three compartments, respectively, associated to GM1, GM3 and caveolar rafts. Following GM1 exogenous addition, the GM3 compartment is depleted of uPAR which is recruited within caveolar rafts thereby triggering angiogenesis.
authors.affiliation: Department of Experimental and Clinical Biomedical Sciences, Section of Experimental Pathology and Oncology, University of Florence, Florence, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Margheri
authors.forename: Laura
authors.initials: L
authors.lastname: Papucci
authors.forename: Nicola
authors.initials: N
authors.lastname: Schiavone
authors.forename: Riccardo
authors.initials: R
authors.lastname: D'Agostino
authors.forename: Silvana
authors.initials: S
authors.lastname: Trigari
authors.forename: Simona
authors.initials: S
authors.lastname: Serratì
authors.forename: Anna
authors.initials: A
authors.lastname: Laurenzana
authors.forename: Alessio
authors.initials: A
authors.lastname: Biagioni
authors.forename: Cristina
authors.initials: C
authors.lastname: Luciani
authors.forename: Anastasia
authors.initials: A
authors.lastname: Chillà
authors.forename: Elena
authors.initials: E
authors.lastname: Andreucci
authors.forename: Tommaso
authors.initials: T
authors.lastname: Del Rosso
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Margheri
authors.forename: Mario
authors.initials: M
authors.lastname: Del Rosso
authors.forename: Gabriella
authors.initials: G
authors.lastname: Fibbi
mesh_terms: D021941:Caveolae / Q000187:drug effects / Q000378:metabolism*; D051242:Caveolin 1 / Q000378:metabolism; D003114:Colony-Forming Units Assay; D066026:Endothelial Progenitor Cells / Q000187:drug effects / Q000378:metabolism*; D005677:G(M1) Ganglioside / Q000494:pharmacology*; D005679:G(M3) Ganglioside / Q000494:pharmacology*; D006801:Humans; D007231:Infant, Newborn; D007700:Kinetics; D021962:Membrane Microdomains / Q000187:drug effects / Q000378:metabolism*; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D010641:Phenotype; D055293:Receptors, Urokinase Plasminogen Activator / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D051242:Caveolin 1; D005679:G(M3) Ganglioside; D055293:Receptors, Urokinase Plasminogen Activator; D005677:G(M1) Ganglioside
keywords: GM1; GM3; MAPKinases; angiogenesis; caveolar-lipid rafts; endothelial colony-forming cells; endothelial progenitor cells; lipid rafts; uPAR