Seizure-like activity leads to the release of BAD from 14-3-3 protein and cell death in hippocampal neurons in vitro.
Seizure-induced neuronal death may involve engagement of the BCL-2 family of apoptosis-regulating proteins. In the present study we examined the activation of proapoptotic BAD in cultured hippocampal neurons following seizures induced by removal of chronic glutamatergic transmission blockade. Kynurenic acid withdrawal elicited an increase in seizure-like electrical activity, which was inhibited by blockers of AMPA (CNQX) and NMDA (MK801 and AP5) receptor function. However, only NMDA receptor antagonists inhibited calcium entry as assessed by fura-2, and cell death of hippocampal neurons. Seizures increased proteolysis of caspase-3 and terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) of cells. Seizure-like activity induced dephosphorylation of BAD and the disruption of its constitutive interaction with 14-3-3 proteins. In turn, BAD dimerized with antiapoptotic BCL-Xl after seizures. However, the absence of neuroprotective effects of pathway intervention suggests that BAD may perform a reinforcement rather than instigator role in cell death following seizures in vitro.
Robert S. Dow Neurobiology Laboratories, Legacy Research, Portland, OR 97232, USA. meller@downneurobiology.org
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Meller
C K
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Schindler
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Chu
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Xiong
J A
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Cameron
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Simon
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Henshall
D048948:14-3-3 Proteins; D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism*; D002478:Cells, Cultured; D053938:DNA Fragmentation / Q000187:drug effects; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D007736:Kynurenic Acid / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D010766:Phosphorylation / Q000187:drug effects; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D018091:Receptors, AMPA / Q000037:antagonists & inhibitors / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000378:metabolism; D012640:Seizures / Q000378:metabolism / Q000503:physiopathology; D016559:Tacrolimus / Q000494:pharmacology; D013997:Time Factors; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism*; D051025:bcl-Associated Death Protein; D051020:bcl-X Protein
D048948:14-3-3 Proteins; C494821:Bad protein, rat; C494813:Bcl2l1 protein, rat; D002352:Carrier Proteins; D018691:Excitatory Amino Acid Antagonists; D019253:Proto-Oncogene Proteins c-bcl-2; D018091:Receptors, AMPA; D016194:Receptors, N-Methyl-D-Aspartate; D051025:bcl-Associated Death Protein; D051020:bcl-X Protein; D014446:Tyrosine 3-Monooxygenase; D007736:Kynurenic Acid; D002118:Calcium; D016559:Tacrolimus