Ethanol impaired neuronal migration is associated with reduced aspartyl-asparaginyl-beta-hydroxylase expression.
Cerebellar hypoplasia in fetal alcohol spectrum disorders (FASD) is associated with inhibition of insulin and insulin-like growth factor (IGF) signaling in the brain. Aspartyl (asparaginyl)-beta-hydroxylase (AAH) is a mediator of neuronal motility, and stimulated by insulin and IGF activation of PI3 kinase-Akt, or inhibition of GSK-3beta. Since ethanol inhibits PI3 Kinase-Akt and increases GSK-3beta activity in brain, we examined the effects of ethanol and GSK-3beta on AAH expression and directional motility in neuronal cells. Control and ethanol-exposed (100 mM x 48 h) human PNET2 cerebellar neuronal cells were stimulated with IGF-1 and used to measure AAH expression and directional motility. Molecular and biochemical approaches were used to characterize GSK-3beta regulation of AAH and neuronal motility. Ethanol reduced IGF-1 stimulated AAH protein expression and directional motility without inhibiting AAH's mRNA. Further analysis revealed that: (1) AAH protein could be phosphorylated by GSK-3beta; (2) high levels of GSK-3beta activity decreased AAH protein; (3) inhibition of GSK-3beta and/or global Caspases increased AAH protein; (4) AAH protein was relatively more phosphorylated in ethanol-treated compared with control cells; and (5) chemical inhibition of GSK-3beta and/or global Caspases partially rescued ethanol-impaired AAH protein expression and motility. Ethanol-impaired neuronal migration is associated with reduced IGF-I stimulated AAH protein expression. This effect may be mediated by increased GSK-3beta phosphorylation and Caspase degradation of AAH. Therapeutic strategies to rectify CNS developmental abnormalities in FASD should target factors underlying the ethanol-associated increases in GSK-3beta and Caspase activation, e.g. IGF resistance and increased oxidative stress.
Carter
Jade J
JJ
Department of Medicine, Rhode Island Hospital and the Warren Alpert Medical School of Brown University, Providence, RI 02903, USA.
Tong
Ming
M
Silbermann
Elizabeth
E
Lahousse
Stephanie A
SA
Ding
Fei Fei
FF
Longato
Lisa
L
Roper
Nitin
N
Wands
Jack R
JR
de la Monte
Suzanne M
SM
D000199:Actins / Q000378:metabolism; D015153:Blotting, Western; D001932:Brain Neoplasms / Q000235:genetics / Q000378:metabolism; D002465:Cell Movement / Q000187:drug effects*; D004797:Enzyme-Linked Immunosorbent Assay; D000431:Ethanol / Q000494:pharmacology*; D019084:Fluorescent Antibody Technique, Indirect; D024581:Glyceraldehyde-3-Phosphate Dehydrogenase (Phosphorylating) / Q000378:metabolism; D038362:Glycogen Synthase Kinase 3 / Q000037:antagonists & inhibitors / Q000502:physiology; D000071679:Glycogen Synthase Kinase 3 beta; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000037:antagonists & inhibitors / Q000494:pharmacology; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D018242:Neuroectodermal Tumors, Primitive / Q000235:genetics / Q000378:metabolism; D009474:Neurons / Q000502:physiology*; D010766:Phosphorylation; D034741:RNA, Small Interfering / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection; D014407:Tumor Cells, Cultured
D000199:Actins; D034741:RNA, Small Interfering; D000431:Ethanol; D007334:Insulin-Like Growth Factor I; D006899:Mixed Function Oxygenases; C058291:aspartic acid 2-oxoglutarate-dependent dioxygenase; D024581:Glyceraldehyde-3-Phosphate Dehydrogenase (Phosphorylating); C000605506:GSK3B protein, human; D000071679:Glycogen Synthase Kinase 3 beta; D038362:Glycogen Synthase Kinase 3