Anti- and pro-oxidant activities of Cu,Zn SOD modulate nitric oxide production

SH-SY5Y neuroblastoma cells were transfected with wild type Cu,Zn SOD (WT cells) or with the G93A Cu,Zn SOD mutant (G93A cells) involved in the familial forms of amyotrophic lateral sclerosis. Both WT and G93A cells had higher expression and activity levels of Cu,Zn SOD with respect to untrasfected cells. However, despite a fully conserved dismutating activity, an increased flux of reactive oxygen species (ROS) was detected in G93A cells. Conversely, a significant lower concentration of ROS was measured in WT cells. The redox unbalance was dependent on G93A Cu,Zn SOD peroxidative activity, as mitochondrial integrity was not affected and nitric oxide (NO) toxicity not involved.