Premium
Synergism of Nitric Oxide and Iron in Killing the Transformed Murine Oligodendrocyte Cell Line N20.1
Author(s) -
Boullerne A. I.,
Nedelkoska L.,
Benjamins J. A.
Publication year - 1999
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.1999.0721050.x
Subject(s) - chemistry , nitric oxide , sodium nitroprusside , dithiothreitol , biochemistry , oligodendrocyte , snap , programmed cell death , peroxynitrite , pharmacology , microbiology and biotechnology , apoptosis , biology , superoxide , endocrinology , myelin , computer graphics (images) , organic chemistry , computer science , enzyme , central nervous system
: Nitric oxide (NO) produced in inflammatory lesions mayplay a major role in the destruction of oligodendrocytes in multiple sclerosisand experimental allergic encephalomyelitis. The transformed murineoligodendroglial line N20.1 is much more resistant than primaryoligodendrocytes to killing by the NO generator S ‐nitroso‐ N ‐acetyl‐DL‐penicillamine (SNAP). This observationprompted investigation of the mechanisms leading to cell death in the N20.1cells and comparison of SNAP with another NO donor, sodium nitroprusside(SNP). We observed that N20.1 cells were 30 times more sensitive to SNP thanto SNAP. The specific NO scavenger2‐phenyl‐4,4,5,5‐tetramethylimidazoline‐1‐oxyl‐3‐oxide (PTIO) protectedagainst SNP only, not against SNAP. However, dithiothreitol protected againstboth SNAP and SNP, indicating that S ‐nitrosylation of cysteines playsa major role in the cytotoxicity of both NO donors. We did not observe anyformation of peroxynitrite or increase of Ca 2+ concentration with either SNAP or SNP, thus excluding their involvement in the mechanisms leading to N20.1 cell death. Based on two observations, (a) potentiation of the cytotoxic effect of SNP when coincubated with ferricyanide or ferrocyanide, but not sodium cyanide, and (b) protection by deferoxamine, an iron cyanide chelator, we conclude that the greater sensitivity of N20.1 cells to SNP compared with SNAP is due to synergism between NO released and the iron cyanide portion of SNP, with the cyanide accounting for very little of the cytotoxicity. Finally, SNP but not SNAP induces some apoptosis, as shown by DNA laddering and protection by a caspase‐3 inhibitor. These results suggest that low levels of NO in combination with increased iron content lead to apoptotic cell death rather than the necrotic cell death seen with higher levels of NO generated by SNAP.