p44/42 MAP kinase and c-Jun N-terminal kinase contribute to the up-regulation of caspase-3 in manganese-induced apoptosis in PC12 cells.
Caspase-3 (32 kDa) is one of the primary protease executioners of apoptosis and is activated by intra-chain proteolytic cleavage, which generates a large subunit (17 kDa) and a small subunit (12 kDa). Typically, after apoptotic stimuli, the level of cleaved caspase-3 increases while that of caspase-3 decreases. It has been shown that caspase-3 mRNA levels increase in cortex following traumatic brain injury or focal ischemia. In the present study, we demonstrate that both caspase-3 mRNA and protein increase in apoptotic PC12 cells following exposure to manganese which strongly induces caspase-3 cleavage. Up-regulation of caspase-3 protein was evident in manganese-treated PC12 cells and was moderate in cisplatin-, rotenone- and A23187-treated cells but was not observed in serum deprivation-, anisomycin-, camptothecin-, cycloheximide- or staurosporine-treated cells in which all treatments induced extensive DNA fragmentation. Manganese-induced up-regulation of caspase-3 mRNA was partially attenuated by the pretreatment with the MEK inhibitor U0126, but not with the c-Jun N-terminal kinase (JNK) inhibitor SP600125. In contrast, the increase in caspase-3 protein was suppressed by both U0126 and SP600125. These results suggest that p44/42 MAPK contributes to the up-regulation of caspase-3 mRNA and the JNK pathway regulates caspase-3 protein levels posttranslationally in manganese-induced apoptosis in PC12 cells.
Ito
Yoshimasa
Y
Department of Biomolecular Science, Faculty of Engineering, Gifu University, Yanagido, Japan.
Oh-Hashi
Kentaro
K
Kiuchi
Kazutoshi
K
Hirata
Yoko
Y
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western / Q000379:methods; D053148:Caspase 3; D020169:Caspases / Q000235:genetics / Q000378:metabolism*; D004347:Drug Interactions; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D048031:JNK Mitogen-Activated Protein Kinases / Q000502:physiology*; D008345:Manganese / Q000494:pharmacology*; D019950:Mitogen-Activated Protein Kinase 1 / Q000502:physiology*; D016716:PC12 Cells; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D013997:Time Factors; D015854:Up-Regulation / Q000187:drug effects*
D004791:Enzyme Inhibitors; D012333:RNA, Messenger; D008345:Manganese; D048031:JNK Mitogen-Activated Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases