Presentation of nitric oxide regulates monocyte survival through effects on caspase-9 and caspase-3 activation.
In the absence of survival factors, blood monocytes undergo spontaneous apoptosis, which involves the activation of caspase-3. Although nitric oxide can block caspase-3 activation and promote cell survival, it can also induce apoptosis. We hypothesized that nitrosothiols that promote protein S-nitrosylation would reduce caspase-3 activation and cell survival, whereas nitric oxide donors (such as 1-propamine 3-(2-hydroxy-2-nitroso-1-propylhydrazine (PAPA) NONOate and diethylamine (DEA) NONOate) that do not target thiol residues would not. Using human monocytes as a model, we observed that nitrosothiol donors S-nitrosoglutathione and S-nitroso-N-acetylpenicillamine suppressed caspase-9 and caspase-3 activity and DNA fragmentation. In contrast, PAPA or DEA NONOate did not promote monocyte survival events and appeared to inhibit monocyte survival induced by macrophage colony-stimulating factor. The caspase-3-selective inhibitor DEVD-fluoromethyl ketone reversed DNA fragmentation events, and the caspase-9 inhibitor LEHD-fluoromethyl ketone reversed caspase-3 activity in monocytes treated with PAPA or DEA NONOate in the presence of macrophage colony-stimulating factor. These results were not caused by differences in glutathione levels or the kinetics of nitric oxide release. Moreover, S-nitrosoglutathione and S-nitroso-N-acetylpenicillamine directly blocked the activity of recombinant caspase-3, which was reversed by the reducing agent dithiothreitol, whereas PAPA or DEA NONOate did not block the enzymatic activity of caspase-3. These data support the hypothesis that nitrosylation of protein thiol residues by nitric oxide is critical for promoting the survival of human monocytes.
Zeigler
Mandy M
MM
Dorothy M. Davis Heart and Lung Research Institute, the Department of Internal Medicine, Ohio State University, Columbus, Ohio 43210-1252, USA.
Doseff
Andrea I
AI
Galloway
Michelle F
MF
Opalek
Judy M
JM
Nowicki
Philip T
PT
Zweier
Jay L
JL
Sen
Chandan K
CK
Marsh
Clay B
CB
D053148:Caspase 3; D053453:Caspase 9; D020169:Caspases / Q000097:blood*; D002470:Cell Survival / Q000187:drug effects*; D053938:DNA Fragmentation / Q000187:drug effects; D004789:Enzyme Activation; D005978:Glutathione / Q000097:blood; D006801:Humans; D006834:Hydrazines / Q000494:pharmacology; D066298:In Vitro Techniques; D007700:Kinetics; D009000:Monocytes / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology; D009569:Nitric Oxide / Q000494:pharmacology*; D020030:Nitric Oxide Donors / Q000494:pharmacology*; D009589:Nitrogen Oxides; D026422:S-Nitrosoglutathione
D006834:Hydrazines; D020030:Nitric Oxide Donors; D009589:Nitrogen Oxides; C112653:PAPA NONOate; D009569:Nitric Oxide; D026422:S-Nitrosoglutathione; C084012:1,1-diethyl-2-hydroxy-2-nitrosohydrazine; C505407:CASP3 protein, human; C506433:CASP9 protein, human; D053148:Caspase 3; D053453:Caspase 9; D020169:Caspases; D005978:Glutathione