Oxidized forms of peroxiredoxins and DJ-1 on two-dimensional gels increased in response to sublethal levels of paraquat.
We previously found hydroperoxide-responsive proteins (HPRPs), which are comprised of peroxiredoxin I (Prx I), Prx II, Prx III, Prx VI, HSP27, G3PDH and two unidentified proteins (HPRP-2' and HPRP-5'), in human umbilical vein endothelial cells. It was demonstrated by two-dimensional polyacrylamide gel electrophoresis (2D PAGE) that most HPRPs are converted into variants with lower pI upon exposure to hydroperoxides. In this study, we examined the HPRP response on 2D gels upon exposure of human endothelial cells (ECV304) to paraquat (PQ2+), which generates reactive oxygen species (ROS) within cells. PQ2+ exerted cytotoxic effects in a dose-(10 microM-10 mM) and time-(24-168 h) dependent manner. Two-dimensional PAGE analysis revealed that HPRP-2', and oxidized forms of Prx I, Prx II and Prx III were clearly increased upon exposure of cells to sublethal levels of PQ2+. Microsequence analysis revealed that both HPRP-2 and -2' were identical with human DJ-1. Moreover immunoblot analysis confirmed the increase of oxidized forms of Prx II, Prx III and DJ-1 in response to sublethal levels of PQ2+. PQ2+ treatment failed to increase fluorescence intensity derived from DCF, which is believed to be an indicator for intracellular levels of hydroperoxide. Although pentachlorophenol (PCP), an uncoupler of the mitochondrial respiratory chain, clearly elevated the fluorescence, PCP had no effect on HPRP response. These observations indicated that DCF-derived fluorescence is not correlated with HPRP response. We consider that the response of Prxs and DJ-1 on 2D gels could reflect endogenous production of ROS in PQ(2+)-treated cells, and might be a sensitive indicator of oxidative stress status.
Mitsumoto
A
A
School of Pharmaceutical Sciences, Kitasato University, Tokyo, Japan.
Nakagawa
Y
Y
Takeuchi
A
A
Okawa
K
K
Iwamatsu
A
A
Takanezawa
Y
Y
D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D002460:Cell Line; D015180:Electrophoresis, Gel, Two-Dimensional; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D015870:Gene Expression; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000737:chemistry / Q000378:metabolism; D055551:HSP27 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D006540:Herbicides / Q000633:toxicity*; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D015151:Immunoblotting; D047908:Intracellular Signaling Peptides and Proteins; D007526:Isoelectric Point; D018832:Molecular Chaperones; D008970:Molecular Weight; D009363:Neoplasm Proteins / Q000378:metabolism; D015513:Oncogene Proteins / Q000378:metabolism*; D010269:Paraquat / Q000633:toxicity*; D010544:Peroxidases / Q000378:metabolism*; D054465:Peroxiredoxin VI; D054464:Peroxiredoxins; D010766:Phosphorylation; D000071617:Protein Deglycase DJ-1; D011817:Rabbits; D017382:Reactive Oxygen Species / Q000378:metabolism
D000975:Antioxidants; D055551:HSP27 Heat-Shock Proteins; C057725:HSPB1 protein, human; D006360:Heat-Shock Proteins; D006540:Herbicides; D047908:Intracellular Signaling Peptides and Proteins; D018832:Molecular Chaperones; D009363:Neoplasm Proteins; D015513:Oncogene Proteins; D017382:Reactive Oxygen Species; D006861:Hydrogen Peroxide; D010544:Peroxidases; D054465:Peroxiredoxin VI; D054464:Peroxiredoxins; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; C105131:PARK7 protein, human; D000071617:Protein Deglycase DJ-1; D010269:Paraquat