title: Differential effects of ethanol on c-jun N-terminal kinase, 14-3-3 proteins, and Bax in postnatal day 4 and postnatal day 7 rat cerebellum.
abstract: These studies investigated ethanol effects on upstream cellular elements and interactions which contribute to Bax-related apoptosis in neonatal rat cerebellum at ages of peak ethanol sensitivity (postnatal day 4 [P4]), compared to later ages of relative resistance (P7). Analyses were made of basal levels of the pro-apoptotic c-jun N-terminal kinase (JNK), Bax, and the 14-3-3 anchoring proteins, as well as the responsiveness of these substances to ethanol at P4 versus P7. Dimerization of Bax with 14-3-3 was also investigated at the two ages following ethanol treatment, a process which sequesters Bax in the cytosol, thus inhibiting its mitochondrial translocation and disruption of the mitochondrial membrane potential. Cultured cerebellar granule cells were used to examine the protective potential of JNK inhibition on ethanol-mediated cell death. Basal levels of JNK were significantly higher at P4 than P7, but no differences in the other proteins were found. Activated JNK, and cytosolic and mitochondrially-translocated Bax were increased in P4 but not P7 animals following ethanol exposure, while protective 14-3-3 proteins were increased only at P7. Ethanol treatment resulted in decreases in Bax:14-3-3 heterodimers at P4, but not at P7. Inhibition of JNK activity in vitro provided partial protection against ethanol neurotoxicity. Thus, differential temporal vulnerability to ethanol in this CNS region correlates with differences in both levels of apoptosis-related substances (e.g., JNK), and differential cellular responsiveness, favoring apoptosis at the most sensitive age and survival at the resistant age. The upstream elements contributing to this vulnerability can be targets for future therapeutic strategies.
authors.affiliation: Department of Neuroscience, University of Florida College of Medicine, USA; McKnight Brain Institute, USA. heaton@mbi.ufl.edu
authors.forename: Marieta Barrow
authors.initials: MB
authors.lastname: Heaton
authors.forename: Michael
authors.initials: M
authors.lastname: Paiva
authors.forename: Stacey
authors.initials: S
authors.lastname: Kubovic
authors.forename: Alexandra
authors.initials: A
authors.lastname: Kotler
authors.forename: Jonathan
authors.initials: J
authors.lastname: Rogozinski
authors.forename: Eric
authors.initials: E
authors.lastname: Swanson
authors.forename: Vladimir
authors.initials: V
authors.lastname: Madorsky
authors.forename: Michelle
authors.initials: M
authors.lastname: Posados
mesh_terms: D048948:14-3-3 Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D051017:Apoptosis Regulatory Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002492:Central Nervous System Depressants / Q000633:toxicity*; D002531:Cerebellum / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D000431:Ethanol / Q000633:toxicity*; D005260:Female; D048031:JNK Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008297:Male; D061251:Primary Cell Culture; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D051381:Rats; D020318:Rats, Long-Evans; D051028:bcl-2-Associated X Protein / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D048948:14-3-3 Proteins; D051017:Apoptosis Regulatory Proteins; C494828:Bax protein, rat; D002492:Central Nervous System Depressants; D047428:Protein Kinase Inhibitors; D051028:bcl-2-Associated X Protein; D000431:Ethanol; D048031:JNK Mitogen-Activated Protein Kinases