Adenine nucleotide metabolism and cell fate after oxidant exposure of rat cortical neurons: effects of inhibition of poly(ADP-ribose) polymerase.
We exposed cultured neurons prelabeled with 14C-adenine to H2O2 with or without the poly(ADP-ribose) polymerase (PARP) inhibitor 3,4-Dihydro-5-[4-(1-piperidinyl)butoxy]-1(2H)-isoquinolinone (DPQ) to quantify its effects on acute ATP depletion, later ATP synthesis, cellular and nuclear morphology, extent of DNA fragmentation, and PARP cleavage. According to the extent of the acute ATP depletion, the exposures were classified as 'mild' (50 microM H2O2), 'moderate' (100-250 microM H2O2), or 'severe' (500 microM-1 mM H2O2) insults. Mild exposure had no significant effects on the parameters studied. In the 'moderately' exposed neurons, ATP depletion to 59+/-6% of control was associated with a decrease in the cell counts, apoptotic morphology, and cleavage of PARP. In this group, DPQ prevented the acute ATP (to 95+/-15% of control), preserved cell morphology, and improved cell survival. In the 'severe' group, ATP depletion to 18+/-4% was associated with necrosis and intact PARP. DPQ elevated ATP levels (to 44+/-12% of control) and post-insult ATP synthesis, improved cell counts, and altered cell morphology towards apoptosis rather than necrosis. Post-insult application of DPQ was less effective. Our results show that the extent of oxidant-induced ATP depletion and cell fate can be modified by PARP inhibition, to some extent also after the insult.
Aito
Henrikka
H
Research Laboratory, Hospital for Children and Adolescents, University of Helsinki, Biomedicum Helsinki, V Floor, Room B524b, P.O. Box 700, FIN-00029 HUS, Helsinki, Finland. henrikka.aito@hus.fi
Aalto
Kristiina T
KT
Raivio
Kari O
KO
D000244:Adenosine Diphosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D002452:Cell Count / Q000379:methods; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D004622:Embryo, Mammalian; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007546:Isoquinolines / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D016877:Oxidants / Q000494:pharmacology*; D010880:Piperidines / Q000494:pharmacology; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D051381:Rats
D004791:Enzyme Inhibitors; D007546:Isoquinolines; D016877:Oxidants; D010880:Piperidines; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; C108729:3,4-dihydro-5-(4-(1-piperidinyl)butoxy)-1(2H)-isoquinolinone; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D011065:Poly(ADP-ribose) Polymerases