Potential role of NADPH-oxidase in early steps of lead-induced oxidative burst in Vicia faba roots.
The mechanism of oxidative burst induced by lead in Vicia faba excised roots was investigated by luminol-dependent chemiluminescence. Results showed that lead triggered a rapid and dose-dependent increase in chemiluminescence production. In this study, specific inhibitors of putative reactive oxygen species (ROS) sources were used to determine the mechanism of lead-induced ROS generation. This generation was sensitive to dephenylene iodonium (DPI), quinacrine and imidazole, some inhibitors of the NADPH-oxidase and not inhibited by other putative ROS sources inhibitors. Data reported in this work clearly demonstrated the pivotal role of NADPH-oxidase-like enzyme in early steps of lead-induced oxidative burst. To investigate the respective implication of calmodulin and protein kinase (PK) in lead-induced NADPH-oxidase activation, excised roots were treated with the calmodulin inhibitor W7 or with the PK inhibitor staurosporine. The chemiluminescence generation inhibition by these inhibitors illustrated the role of PK in lead-induced NADPH-oxidase activation and revealed a calmodulin-dependent step. Using the calcium entry blocker La(3+) or different concentrations of calcium in the extra-cellular medium, our data highlighted the implication of Ca(2+) channel in lead-induced oxidative burst.
Pourrut
Bertrand
B
EcoLab UMR 5245 CNRS-UPS-INPT, ENSAT Avenue de l'agrobiopole-Auzeville-Tolosane Castanet-Tolosan, France.
Perchet
Geoffrey
G
Silvestre
Jérôme
J
Cecchi
Marie
M
Guiresse
Maritxu
M
Pinelli
Eric
E
D015220:Calcium Channels / Q000378:metabolism; D002147:Calmodulin / Q000378:metabolism; D003300:Copper / Q000378:metabolism; D007854:Lead / Q000378:metabolism / Q000633:toxicity*; D008163:Luminescent Measurements; D019255:NADPH Oxidases / Q000378:metabolism*; D010084:Oxidation-Reduction / Q000187:drug effects; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000378:metabolism; D018517:Plant Roots / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology*; D011494:Protein Kinases / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D016897:Respiratory Burst / Q000187:drug effects*; D031307:Vicia faba / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology*; D014969:Xanthine Oxidase / Q000378:metabolism; D000097667:Polyamine Oxidase
D015220:Calcium Channels; D002147:Calmodulin; D003300:Copper; D007854:Lead; D019255:NADPH Oxidases; D000587:Oxidoreductases Acting on CH-NH Group Donors; D011494:Protein Kinases; D017382:Reactive Oxygen Species; D014969:Xanthine Oxidase; D000097667:Polyamine Oxidase