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Ethanol‐Mediated DNA Damage and PARP‐1 Apoptotic Responses in Cultured Fetal Cortical Neurons
Author(s) -
Cherian Priscilla P.,
Schenker Steven,
Henderson George I.
Publication year - 2008
Publication title -
alcoholism: clinical and experimental research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.267
H-Index - 153
eISSN - 1530-0277
pISSN - 0145-6008
DOI - 10.1111/j.1530-0277.2008.00769.x
Subject(s) - poly adp ribose polymerase , tunel assay , apoptosis , dna damage , blot , apoptosis inducing factor , biology , microbiology and biotechnology , terminal deoxynucleotidyl transferase , programmed cell death , oxidative stress , chemistry , caspase , biochemistry , polymerase , dna , gene
Background: Prior studies by many laboratories have illustrated that ethanol can elicit a cascade of caspase‐dependent apoptotic events in cultured neurons. Studies in our laboratory have connected this to oxidative stress and effects on fetal cortical neuron glutathione homeostasis. Aims: The intent of the following studies is to address mechanisms underlying ethanol‐associated DNA damage that may be connected to apoptotic death of neurons. Methods: Cultures of fetal rat cerebral cortical neurons were utilized. Estimates of DNA damage was determined by Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining and nuclear condensation; Poly(ADP‐ribose) polymerase‐1 (PARP‐1) expression was determined by immunostaining and Western blotting; and occurrence of parylation and AIF translocations were assessed by Western blotting. Results: Ethanol treatment of the neurons generated increases in DNA damage by 4 hours while nuclear condensation was low at the short exposure period but increased markedly by 24 hours. This was temporally related to a marked up‐regulation of PARP‐1 expression. Activity of PARP‐1, as assessed by PolyADP‐ribose (PAR) formation, occurred within 15 minutes and peaked by 6 to 8 hours of ethanol treatment. An almost complete translocation of apoptosis inducing factor (AIF) from mitochondria to the nucleus occurred by 24 hours of ethanol treatment (4.0 mg/ml). Ethanol treatment for 4, 12, and 24 hours elicited an increasing caspase‐mediated cleavage of PARP‐1 to its 24 kDa fragment. Conclusions: These data illustrate the rapid occurrence of DNA damage following ethanol exposure and that PARP‐1 pathways may play a role in the subsequent apoptotic death of these neurons.