title: Effect of growth factors on DNA labeling and cytoskeletal protein expression in 17-beta-estradiol and basic fibroblast growth factor pre-treated astrocyte cultures.
abstract: Astrocytes react to all noxae which damage neurons. Their reactions include degeneration, hypertrophy, hyperplasia and fibre formation. Growth factors inducing proliferation and differentiation of both neurons and astrocytes in culture play a pivotal role in the dynamic flow of signaling molecules between neurons and astroglia. Estrogens as well influence astroglia and are neuroprotectants. This study has investigated the interactions between growth factors and estrogens on DNA labeling and cytoskeletal protein [glial fibrillary acidic protein (GFAP) and vimentin] expression in 22 DIV astrocyte cultures treated for 24 or 36 h under different experimental conditions. Contemporary addition of 17-beta-estradiol (E2) with two or three growth factors for 24 h, significantly stimulated methyl-[3H]thymidine incorporation into DNA from 22 days in vitro (DIV) astrocyte cultures. This effect reached a peak when E2 was co-added with epidermal growth factor (EGF), basic fibroblast growth factor (bFGF) and insulin. In astrocyte cultures treated for 36 h with E2 and EGF + insulin or bFGF + insulin added in the last 12 h, DNA labeling was remarkably increased. The parallel cyclin Dl expression positively correlated with ERK2 activation. Western blot analysis for cytoskeletal proteins showed also changes of both GFAP and vimentin expression. The above data suggest the occurrence of a scheduled interaction between "competence" or "progression" growth factors and estrogens on DNA labeling and cytoskeletal protein expression during astroglial cell proliferation and differentiation in culture. A better understanding of the mechanisms of these interactions may contribute to develop strategies for controlling astroglial reaction in cerebrovascular disease including stroke and hypertensive brain damage.
authors.affiliation: Department of Chemical Sciences, Section of Biochemistry and Molecular Biology, University of Catania, Catania, Italy. robertoavola@unict.it
authors.forename: Roberto
authors.initials: R
authors.lastname: Avola
authors.forename: Gianfrancesco
authors.initials: G
authors.lastname: Cormaci
authors.forename: Venera
authors.initials: V
authors.lastname: Mazzone
authors.forename: Luca
authors.initials: L
authors.lastname: Denaro
authors.forename: Fiorenzo
authors.initials: F
authors.lastname: Mignini
authors.forename: Daniele
authors.initials: D
authors.lastname: Tomassoni
authors.forename: Damiano
authors.initials: D
authors.lastname: Zaccheo
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000166:cytology / Q000187:drug effects*; D015153:Blotting, Western; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured / Q000187:drug effects; D003598:Cytoskeletal Proteins / Q000096:biosynthesis* / Q000187:drug effects*; D004247:DNA / Q000096:biosynthesis* / Q000187:drug effects*; D004815:Epidermal Growth Factor / Q000627:therapeutic use; D004958:Estradiol / Q000627:therapeutic use*; D016222:Fibroblast Growth Factor 2 / Q000627:therapeutic use; D006133:Growth Substances / Q000627:therapeutic use*; D007328:Insulin / Q000627:therapeutic use; D007334:Insulin-Like Growth Factor I / Q000627:therapeutic use; D023421:Models, Animal; D051381:Rats; D013194:Staining and Labeling; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D003598:Cytoskeletal Proteins; D006133:Growth Substances; D007328:Insulin; D016222:Fibroblast Growth Factor 2; D004958:Estradiol; D004815:Epidermal Growth Factor; D007334:Insulin-Like Growth Factor I; D004247:DNA