title: Kinin-B2 receptor expression and activity during differentiation of embryonic rat neurospheres.
abstract: Neural progenitor cells were isolated from rat fetal telencephalon and proliferate as neurospheres in the presence of EGF, FGF-2, and heparin. In the absence of these growth factors, neurospheres differentiate into neurons, astrocytes, and oligodendrocytes. Using an embryonal carcinoma cell line as in vitro differentiation model, we have already demonstrated the presence of an autocrine loop system between kinin-B2 receptor activity and secretion of its ligand bradykinin (BK) as prerequisites for final neuronal differentiation (Martins et al., J Biol Chem 2005; 280: 19576-19586). The aim of this study was to verify the activity of the kallikrein-kinin system (KKS) during neural progenitor cell differentiation. Immunofluorescence studies and flow cytometry analysis revealed increases in glial fibrillary acidic protein and beta-3 tubulin expression and decrease in the number of nestin-positive cells along neurospheres differentiation, indicating the transition of neural progenitor cells to astrocytes and neurons. Kinin-B2 receptor expression and activity, secretion of BK into the medium, and presence of high-molecular weight kininogen suggest the participation of the KKS in neurosphere differentiation. Functional kinin-B2 receptors and BK secretion indicate an autocrine loop during neurosphere differentiation to neurons, astrocytes, and oligodendrocytes, reflecting events occurring during early brain development.
authors.affiliation: Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil.
authors.forename: Antonio H
authors.initials: AH
authors.lastname: Martins
authors.forename: Janaína M
authors.initials: JM
authors.lastname: Alves
authors.forename: Cleber A
authors.initials: CA
authors.lastname: Trujillo
authors.forename: Telma T
authors.initials: TT
authors.lastname: Schwindt
authors.forename: Gabriela F
authors.initials: GF
authors.lastname: Barnabé
authors.forename: Fabiana L T
authors.initials: FL
authors.lastname: Motta
authors.forename: Alessander O
authors.initials: AO
authors.lastname: Guimaraes
authors.forename: Dulce E
authors.initials: DE
authors.lastname: Casarini
authors.forename: Luiz E
authors.initials: LE
authors.lastname: Mello
authors.forename: João B
authors.initials: JB
authors.lastname: Pesquero
authors.forename: Henning
authors.initials: H
authors.lastname: Ulrich
mesh_terms: D000818:Animals; D018236:Carcinoma, Embryonal / Q000378:metabolism; D002454:Cell Differentiation; D002460:Cell Line; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D007610:Kallikreins / Q000737:chemistry; D008297:Male; D008954:Models, Biological; D009474:Neurons / Q000166:cytology* / Q000378:metabolism* / Q000473:pathology; D051381:Rats; D017208:Rats, Wistar; D043782:Receptor, Bradykinin B2 / Q000096:biosynthesis*; D013234:Stem Cells / Q000166:cytology
chemical_list: D043782:Receptor, Bradykinin B2; D007610:Kallikreins