Potassium deprivation-induced apoptosis of cerebellar granule neurons: a sequential requirement for new mRNA and protein synthesis, ICE-like protease activity, and reactive oxygen species.
Potassium (K+) deprivation-induced apoptosis of cerebellar granule neurons requires new mRNA and protein synthesis. Using a fluorogenic substrate for interleukin-1beta converting enzyme (ICE), we show that K+ deprivation of cerebellar granule neurons induces cycloheximide-sensitive ICE-like protease activity. A peptide inhibitor of ICE-like protease activity, Ac-YVAD-chloromethylketone (Ac-YVAD-CMK), prevents K+ deprivation-induced apoptosis. Further, reactive oxygen species (ROS) are essential mediators of K+ deprivation-induced apoptosis of cerebellar granule neurons because neuronal death is also blocked by superoxide dismutase, N-acetyl-L-cysteine, and free radical spin traps. Using fluorescent assays, we show that ROS production after K+ deprivation is blocked by actinomycin D, cycloheximide, and Ac-YVAD-CMK, suggesting that ROS act downstream of gene transcription, mRNA translation, and ICE activation. Taken together, we show that new mRNA and protein synthesis, activation of ICE-like proteases, and ROS production are sequential events in K+ deprivation-induced apoptosis of cerebellar granule neurons.
Schulz
J B
JB
Department of Neurology, University of Tübingen, Germany.
Weller
M
M
Klockgether
T
T
D000818:Animals; D017209:Apoptosis; D002531:Cerebellum / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism*; D011188:Potassium / Q000494:pharmacology*; D011480:Protease Inhibitors / Q000494:pharmacology; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
D011480:Protease Inhibitors; D012333:RNA, Messenger; D011188:Potassium; D010100:Oxygen