The effects of zinc supplementation on autophagy in primary human fetal retinal pigment epithelial cells - New molecular target pathway

Purpose: Autophagy is thought to be a response to increased oxidative stress in age related macular degeneration (AMD) and it has been suggested that modulation of autophagy flux could become a treatment strategy for the disease. The ARED study showed that zinc supplementation can reduce the progression of AMD, raising the possibility, that zinc might be directly involved in regulating cellular processes during disease progression. In this study we tested the hypothesis that zinc supplementation can directly affect autophagy. Methods: Primary human fetal RPE cells (ScienceCell) were cultured on polyester transwells (Corning), coated with Geltrex for 4 and 31 days in the presence or absence of 125 μM externally added ZnSO. Autophagosome number was induced by Chloroquine or Bafilomycin, visualized using CytoID kit (Enzo) and the Opera high content screening system (PerkinElmer) and quantified by ImageJ. Distribution of autophagosomes were examined by confocal (Zeiss LSM 700) and transmission electron microscopy (Jeol 1010). Results: There was a small, but significant decrease in autophagosome numbers with increasing differentiation in non-treated cells (1.77±0.31 vs. 0.65±0.15; p