CONICET | Buscador de Institutos y Recursos Humanos

CHARACTERIZATION OF AN IRON OVERLOAD MODEL IN HUMAN IMR-32 NEUROBLASTOMA CELLS. Gabriela Salvador1 and Patricia I. Oteiza2 1INIBIBB, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional del Sur, Argentina 2Departments of Nutrition and Environmental Toxicology, University of California, Davis Excess neuronal iron has been proposed to contribute to the pathology of several neurodegenerative diseases including Alzheimer´s and Parkinson´s disease. This work characterized the exposure of human neuroblastoma IMR-32 cells to ferric ammonium citrate (FAC) as a potential model of neuronal iron overload and neurodegeneration. The consequences of FAC treatment on neuronal oxidative stress and on the modulation of the oxidant-sensitive transcription factors AP-1 and NF-κB were investigated. IMR-32 cells exposure to FAC (150 μM) resulted in a time (3-72 h)- dependent increase in cellular iron (17-736 nmol/mg protein) content and led to increased cell oxidant levels evaluated with the probe DCDHF. FAC exposure caused a time-dependent (3-48 h) increase in nuclear AP-1- and NF-κB-DNA binding measured by EMSA. This was associated with the upstream activation of the mitogen activated kinases ERK1/2, JNK and p38, and of IκBα. After 72 h incubation with FAC, cell viability was 40% lower than in controls. Caspase 3 activation (activity and PARP cleavage) after 48 h of treatment suggests that FAC-associated iron overload triggers apoptotic death in IMR-32 neuronal cells. In summary, the exposure of neuroblastoma cells to FAC is associated with high oxidant cell levels, activation of redox-sensitive signals, and apoptosis. Results suggest that this is a good model to study the iron neurotoxicity and the role of iron overload in neurodegenerative diseases. Supported by a Fulbright-CONICET fellowship to G.S. and the University of California, Davis, USA.