ANALYSIS OF THE BEHAVIOR OF NEURAL STEM CELLS UNDER OXIDATIVE STRESS INDUCED BY IRON AND COPPER

PEREZ, BANCHIO

Congreso; SAIB; 2018

Traditionally, it was thought that the mammalian nervous system lacked the ability to self-repair after injuries or neurodegeneration. We now know that the adult brain does indeed hold the capacity to regenerate, albeit to a limited extent. Endogenous neural stem cells (NSCs) could be a regenerative source for the damaged neural cells but because their number and regenerative ability are limited, they cannot fully repair the damaged tissue. Factors present in the injured microenvironment (such as inflammatory mediators and reactive oxygen species (ROS)) influence survival, self-renewal, migration and neuronal differentiation of both endogenous NSCs and transplanted exogenous stem cells.In order to test this hypothesis, we used the transition metals iron and copper to induce oxidative stress in NSCs. To determine the appropriate concentration and exposure time, the viability of the cultures treated with metals was assessed using the MTT assay and by Trypan Blue staining. To evaluate the extent of metal-induced effects on NSCs, cell morphology and generation of ROS (measured by using the probe DCFH-DA) were analyzed. Moreover, the type of cell death after the exposure to iron and copper was evaluated by differential nuclear staining with fluorescent dyes acridine orange and ethidium bromide. We demonstrate that both metals can stimulate the production of ROS in NSCs cultures an induce apoptosis or necrosis of the stem cells.Additionally, we investigated the effects of iron and copper on the ability of NSCs to proliferate and generate new neurospheres or to differentiate into neurons. We have shown that both metals affect NSCs survival under proliferation conditions. Furthermore, by immunofluorescence and western blot analysis using specific markers, we demonstrated that metals promote neuronal differentiation, perhaps, as part of an intrinsic mechanism of the central nervous system to repair the damaged tissue.