title: Cellular characterization of epidermal growth factor-expanded free-floating neurospheres.
abstract: Neural stem cells proliferate in liquid culture as cell clusters (neurospheres). This study was undertaken to characterize the epidermal growth factor (EGF)-expanded free-floating neurospheres derived from rat fetal striatum. We examined the ultrastructural and antigenic characteristics of these spheres. They consisted of two cell types, electron-dense and electron-lucent cells. Lucent cells were immunopositive to actin, vimentin, and nestin, whereas dense cells were immunopositive to actin, weakly positive to vimentin, and nestin-negative. Neurospheres contained healthy, apoptotic, and necrotic cells. Healthy cells were attached to each other by adherens junctions. They showed many pseudopodia and occasionally a single cilium. Sphere cells showed phagocytic capability because healthy cells phagocytosed the cell debris derived from dead cells in a particular process that involves the engulfment of dying cells by cell processes from healthy cells. Sphere cells showed a cytoplasmic and a nuclear pool of fibroblast growth factor (FGF) receptors. They expressed E- and N-cadherin, alpha- and beta-catenin, EGF receptor, and a specific subset of FGF receptors. Because sphere cells expressed this factor in the absence of exogenous FGF-2, we propose that they are able to synthesize FGF-2.
authors.affiliation: Departamento de Investigación, Hospital Ramón y Cajal, Madrid, Spain.
authors.forename: Maria V T
authors.initials: MV
authors.lastname: Lobo
authors.forename: F Javier M
authors.initials: FJ
authors.lastname: Alonso
authors.forename: Carolina
authors.initials: C
authors.lastname: Redondo
authors.forename: Miguel A
authors.initials: MA
authors.lastname: López-Toledano
authors.forename: Enrique
authors.initials: E
authors.lastname: Caso
authors.forename: Antonio S
authors.initials: AS
authors.lastname: Herranz
authors.forename: Carlos Luis
authors.initials: CL
authors.lastname: Paíno
authors.forename: Diana
authors.initials: D
authors.lastname: Reimers
authors.forename: Eulalia
authors.initials: E
authors.lastname: Bazán
mesh_terms: D000818:Animals; D015815:Cell Adhesion Molecules / Q000378:metabolism; D002454:Cell Differentiation; D002478:Cells, Cultured; D003342:Corpus Striatum / Q000166:cytology* / Q000648:ultrastructure; D003598:Cytoskeletal Proteins / Q000378:metabolism; D004815:Epidermal Growth Factor / Q000378:metabolism*; D066246:ErbB Receptors / Q000378:metabolism; D005333:Fetus; D051381:Rats; D017207:Rats, Sprague-Dawley; D013234:Stem Cells / Q000378:metabolism / Q000648:ultrastructure*; D015291:Transforming Growth Factors / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D015815:Cell Adhesion Molecules; D003598:Cytoskeletal Proteins; D014409:Tumor Necrosis Factor-alpha; D004815:Epidermal Growth Factor; D015291:Transforming Growth Factors; D066246:ErbB Receptors