[Possible involvement of caspase activation in nitric oxide-induced neuronal apoptosis in SH-SY5Y cells].
We here report involvement of caspases in NO-induced neuronal apoptosis. Our experiments were designed to elucidate how NO induces neuronal cell death using NOC18, a new type of NO donor that spontaneously releases NO alone, without enzymatic metabolization. NOC18 induced apoptosis in human neuroblastoma SH-SY5Y cells in a concentration- and time-dependent manner estimated with DNA fragmentation assay, FACScan analysis, and nuclear morphology. In this study, oxyhemoglobin, an NO trapper, suppressed NOC18-triggered DNA fragmentation, indicating that NO from NOC18 is an apoptosis-inducer. An increase in caspase-3-like protease activity was observed in parallel with the induction of apoptosis, but no caspase-1-like protease activity was detected. The level of pro-caspase-2 protein, a precursor of caspase-2, was decreased dramatically. In addition, NOC18 also caused the cleavage of PARP, yielding an 85 kDa protein, a typical fragment of the caspases reaction. Oxyhemoglobin blocked the decrease in pro-caspase-2 and the cleavage of PARP by NOC18. Moreover, NO elicited the release of cytochrome c into the cytosol from mitochondria during apoptosis. These results suggest that activation of caspases by cytochrome c released from mitochondria is involved in neuronal apoptosis induced by NO.
Uehara
T
T
Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan.
Nomura
Y
Y
D017209:Apoptosis / Q000502:physiology*; D020169:Caspases / Q000378:metabolism*; D003574:Cytochrome c Group / Q000378:metabolism; D053938:DNA Fragmentation; D004789:Enzyme Activation; D006801:Humans; D009447:Neuroblastoma / Q000473:pathology; D009474:Neurons / Q000502:physiology*; D009569:Nitric Oxide / Q000494:pharmacology*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D009603:Nitroso Compounds / Q000494:pharmacology; D010108:Oxyhemoglobins / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D003574:Cytochrome c Group; C093285:NOC 18; D020030:Nitric Oxide Donors; D009603:Nitroso Compounds; D010108:Oxyhemoglobins; D009569:Nitric Oxide; D020169:Caspases