Potential role of NADPH-oxidase in early steps of lead-induced oxidative burst in Vicia faba roots

• DOI: 10.1016/j.jplph.2007.07.016
• Publication Date: 2007-11-14T17:59:11Z
• Authors: Bertrand Pourrut; Geoffrey Perchet; Jérôme Silvestre; Marie Cecchi; Maritxu Guiresse; Eric Pinelli
• Keywords: Xanthine Oxidase; Biodiversité et Ecologie; Plant Roots; 03 medical and health sciences; Reactive oxygenspecies; Calmodulin; Respiratory Burst; [SDV.EE]Life Sciences [q-bio]/Ecology, environment; Ecologie, Environnement; Oxidoreductases Acting on CH-NH Group Donors; 0303 health sciences; Ecologie; 500; NADPH Oxidases; Oxidative burst; Environnement; Vicia faba; [SDE.BE] Environmental Sciences/Biodiversity and Ecology; [SDV.EE] Life Sciences [q-bio]/Ecology, environment; Lead; Polyamine Oxidase; Luminescent Measurements; Calcium Channels; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; Reactive oxygen species; Reactive Oxygen Species; Oxidation-Reduction; Protein Kinases; NADPH-oxidase; Copper

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.