title: FGF-2/FGFR1 neurotrophic system expression level and its basal activation do not account for the age-dependent decline of precursor cell proliferation in the subventricular zone of rat brain.
abstract: It is largely accepted that neurogenesis in the adult brain decreases with age and reduced levels of local neurotrophic support is speculated to be a contributing factor. Among neurotrophic factors involved on neurogenesis, we focused our attention on the neurotrophic system fibroblast growth factor-2 (FGF-2) and its receptor FGFR1, a potent modulator of precursor cell proliferation. In the present work, we aimed to analyse if potential age-dependent changes of the FGF-2/FGFR1 neurotrophic system may give account for the age-dependent decline of precursor cell proliferation in the neurogenic region of the subventricular zone (SVZ) in the rat brain. Using in situ hybridization and western blotting procedures we examined FGF-2 and FGFR1 expression levels in the SVZ of 20-month-old rats as compared to young adult 3-month-old rats. The results showed that during aging the FGF-2 and its receptor expression levels, both as mRNA and protein, were unchanged in the SVZ. The levels of phosphorylated FGFR1 form did not show significant variations suggesting that also the level of receptor activation does not change during aging. No changes were also observed in the phosphorylation of two FGFR1 related proteins involved in intracellular signaling, the canonical extracellular signal-regulated kinase Erk1/2 and the phospholipase-Cγ1. Additionally, we could show that also the proliferation rate of stem cells does not change during aging. Taken together, our results show that FGF-2/FGFR1 neurotrophic system expression level and its basal activation do not account for the age-dependent decline of precursor cell proliferation in the rat brain.
authors.affiliation: Department of Experimental Biomedicine and Clinical Neuroscience, div. Human Physiology, Laboratory of Molecular Neurobiology, University of Palermo, corso Tukory 129, IT-90134 Palermo, Italy.
authors.forename: Monica
authors.initials: M
authors.lastname: Frinchi
authors.forename: Valentina
authors.initials: V
authors.lastname: Di Liberto
authors.forename: Melania
authors.initials: M
authors.lastname: Olivieri
authors.forename: Kjell
authors.initials: K
authors.lastname: Fuxe
authors.forename: Natale
authors.initials: N
authors.lastname: Belluardo
authors.forename: Giuseppa
authors.initials: G
authors.lastname: Mudò
mesh_terms: D053687:Adult Stem Cells / Q000502:physiology*; D000375:Aging / Q000502:physiology*; D000818:Animals; D001921:Brain / Q000033:anatomy & histology; D001973:Bromodeoxyuridine / Q000378:metabolism; D049109:Cell Proliferation; D002552:Cerebral Ventricles / Q000166:cytology*; D016220:Fibroblast Growth Factor 1 / Q000235:genetics / Q000378:metabolism; D016222:Fibroblast Growth Factor 2 / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000502:physiology*; D008297:Male; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D055495:Neurogenesis; D051966:Phospholipase C gamma / Q000378:metabolism; D010766:Phosphorylation / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D051496:Receptor, Fibroblast Growth Factor, Type 1 / Q000378:metabolism*
chemical_list: D012333:RNA, Messenger; D016222:Fibroblast Growth Factor 2; D016220:Fibroblast Growth Factor 1; C496350:Fgfr1 protein, rat; D051496:Receptor, Fibroblast Growth Factor, Type 1; D048052:Mitogen-Activated Protein Kinase 3; D051966:Phospholipase C gamma; D001973:Bromodeoxyuridine