Retinal pigment epitheliuma major role in retinal oxidative stress

Resumo

The present study reports the cellular effects of EtOH on ARPE-19 cells and determine that EtOH exposure induces the formation of 4-HNE-aggresomes, together with other neurodegenerative hallmarks such as mitochondrial damage and autophagy activation. Considering the central role of RPE in retinal physiology and pathophysiology, and its neural origin, these findings render new insights into the mechanism of neurodegeneration caused by alcohol toxicity in retinal cells, and may contribute to the development of therapeutic strategies in several nervous and retinal diseases. CYP2E1 metabolizes EtOH leading to production of ROS and acetaldehyde, which are known to cause not only liver damage but also toxicity to other organs. Herein, there is a characterization, for the first time, of CYP2E1 in the human RPE cell line ARPE-19 and its inducibility by EtOH. CYP2E1-derived ROS are also proposed as responsible for the EtOH-induced damage in these cells, since CMZ (as known inhibitor of CYP2E1) and NAC (an antioxidant), prevented its induction and derived ROS production. Moreover, the exosome machinery has been proposed as a communication tool of the cell, and this is not different in the retina. It is therefore very important to characterize retinal exosomes and to understand their function. It describes herein and for the first time, that EtOH, as oxidative insult, was able to stimulate exosomes production in ARPE-19 cells. Thus, because of the known biological functions of exosomes, further understanding of exosomal transport of growth factors and or signaling molecules in the retina in pathological conditions could provide valuable information toward of understanding retinal diseases. Finally, in the present thesis, it proposes a new protocol for the generation of RPE from hPSCs, in which RPE cells are isolated from three-dimensional retinal cups. These RPE cells demonstrated many characteristics of native RPE, including pigmentation, characteristic morphology and key markers expression. Research studies will be more relevant if hPSC-RPE cells were used as an in vitro model.