Vascular endothelial growth factor promotes neurite maturation in primary CNS neuronal cultures.
Recent studies have demonstrated that vascular endothelial growth factor (VEGF) and its receptor VEGFR2 (flk-1) are expressed by neurons during development and following hypoxic-ischemic events. Moreover, fetal CNS tissue explants exposed to exogenous VEGF exhibit increased neuronal Map-2 expression, suggesting that VEGF could have an effect on neuronal maturation. To determine whether this effect is of a direct nature, we examined the expression of Map-2 in the presence of VEGF in primary CNS neuronal cultures. After 3 days in culture, a statistically significant dose-dependent increase in the length of Map-2(+) processes was observed, with the peak occurring at 10 ng/ml of VEGF. Immunohistochemical analysis of the cultures demonstrated the presence of VEGFR2 after VEGF treatment, as well as the expression of the VEGF receptor VEGFR1 (flt-1). Treatment of the cultures with antisense oligonucleotides against VEGFR2, but not against VEGFR1, abolished the effect of VEGF on the length of Map-2(+) processes. RT-PCR analyses of Map-2 and VEGFR1 indicated that mRNAs of these two genes are upregulated in the presence of VEGF. The addition of wortmannin, an inhibitor of PI3K/Akt signal-transduction pathway, to the media did not affect the VEGF-dependent increase in Map-2(+) length. In contrast PD98059, which inhibits the MAPK pathway, partially abolished this effect of VEGF. These experiments suggest that VEGF has a direct effect on neuronal growth and maturation under normoxic conditions during CNS development, which is mediated by the VEGFR2 receptor via the MAPK pathway.
Khaibullina
Alfia A
AA
The George Washington University, Medical Center, Department of Anatomy and Cell Biology, 2300 I Street, NW, Washington, DC 20037, USA.
Rosenstein
Jeffrey M
JM
Krum
Janette M
JM
D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D002490:Central Nervous System / Q000166:cytology* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects; D007150:Immunohistochemistry / Q000379:methods; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D016501:Neurites / Q000187:drug effects* / Q000502:physiology; D009474:Neurons / Q000187:drug effects* / Q000502:physiology; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D010751:Phosphopyruvate Hydratase / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D014404:Tubulin / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000494:pharmacology*; D040281:Vascular Endothelial Growth Factor Receptor-1 / Q000378:metabolism; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000235:genetics / Q000378:metabolism; D000077191:Wortmannin
D000730:Androstadienes; D004791:Enzyme Inhibitors; D005419:Flavonoids; D008869:Microtubule-Associated Proteins; D016376:Oligonucleotides, Antisense; D012333:RNA, Messenger; D014404:Tubulin; D042461:Vascular Endothelial Growth Factor A; D040281:Vascular Endothelial Growth Factor Receptor-1; D040301:Vascular Endothelial Growth Factor Receptor-2; D010751:Phosphopyruvate Hydratase; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one; D000077191:Wortmannin