Title of article :
Reactive oxygen species derived from the mitochondrial respiratory chain are not responsible for the basal levels of oxidative base modifications observed in nuclear DNA of mammalian cells
Author/Authors :
Simone Hoffmann، نويسنده , , Dimitry Spitkovsky، نويسنده , , J. Pablo Radicella، نويسنده , , Bernd Epe، نويسنده , , Rudolf J. Wiesner، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2004
Abstract :
The mitochondrial electron transport chain (ETC) is the most important source of reactive oxygen species (ROS) in mammalian cells. To assess its relevance to the endogenous generation of oxidative DNA damage in the nucleus, we have compared the background (steady-state) levels of oxidative DNA base modifications sensitive to the repair glycosylase Fpg (mostly 7,8-dihydro-8-oxoguanine) in wild-type HeLa cells and HeLa ρ0 cells. The latter are depleted of mitochondrial DNA and therefore are unable to produce ROS in the ETC. Although the levels of ROS measured by flow cytometry and redox-sensitive probes in ρ0 cells were only 10–15% those of wild-type cells, steady-state levels of oxidative DNA base modifications were the same as in wild-type cells. Mitochondrial generation of ROS was then stimulated in HeLa wild-type cells using inhibitors interfering with the ETC. Although mitochondrial ROS production was raised up to 6-fold, none of the substances nor their combinations induced additional oxidative base modifications in the nuclear DNA. This was also true for glutathione-depleted cells. The results indicate that the contribution of mitochondria to the endogenously generated background levels of oxidative damage in the nuclear DNA is negligible.
Keywords :
Mitochondria , reactive oxygen species , Endogenous DNA damage , 8-Dihydro-8-oxoguanine , 7 , free radicals
Journal title :
Free Radical Biology and Medicine
Journal title :
Free Radical Biology and Medicine