Ethanol inhibition of neural stem cell differentiation is reduced by neurotrophic factors.
BACKGROUND
Ethanol exposure during development leads to various forms of neuronal damage. Because neural stem cells (NSCs) play a pivotal role in the development and maturation of the central nervous system, it is important to understand the effect of ethanol on NSC differentiation. In this study, we investigated the effect of ethanol on differentiation of cultured NSCs in the presence and absence of neurotrophic factors.


METHODS
NSCs were derived from rat embryos on embryonic day 14. Cells were exposed to ethanol with or without neurotrophic factors, insulin-like growth factor-1 (IGF-1), or brain-derived neurotrophic factor (BDNF). The effect of ethanol on differentiation was quantified by measurement of optical density of each sample following to microtubule-associated protein 2 enzyme-linked immunosorbent assay and counting of the number of microtubule-associated protein 2-positive cells microscopically. In addition, cell viability of cultured cortical neurons that were exposed to similar concentrations of ethanol was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay.


RESULTS
Ethanol (20-100 mM) inhibited NSC differentiation induced by basic fibroblast growth factor removal, whereas those concentrations of ethanol did not affect neuronal survival. Both IGF-1 and BDNF promoted generation of neurons in the absence of ethanol. Moreover, they suppressed the inhibitory effect of ethanol on NSC differentiation.


CONCLUSIONS
Ethanol inhibited NSC differentiation at concentrations much lower than what compromised neuronal survival. Ethanol-induced differential inhibition was reduced by both IGF-1 and BDNF. These results suggest that ethanol inhibits stem cell differentiation through alteration of cellular pathways related to neurotrophic factor signaling.
Department of Neuropsychiatry, Sapporo Medical University, School of Medicine, Sapporo, Japan. tatema@sapmed.ac.jp
Masaru
M
Tateno
Wataru
W
Ukai
Hiroki
H
Ozawa
Megumi
M
Yamamoto
Sadamu
S
Toki
Hiroshi
H
Ikeda
Toshikazu
T
Saito
D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects* / Q000502:physiology; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D000431:Ethanol / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D005260:Female; D006131:Growth Inhibitors / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D009414:Nerve Growth Factors / Q000494:pharmacology*; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D011247:Pregnancy; D051381:Rats; D017208:Rats, Wistar; D013234:Stem Cells / Q000166:cytology / Q000187:drug effects* / Q000502:physiology
D006131:Growth Inhibitors; D009414:Nerve Growth Factors; D000431:Ethanol