Human retinal pigment epithelial cells dying through autophagy are engulfed by professional and non‐professional phagocytes

Abstract

AbstractPurpose Inefficient removal of dying retinal pigment epithelial (RPE) cells by professional and non‐professional phagocytes can result in debris formation and development of age‐related macular degeneration (AMD). We aimed to study the clearance of autophagic dying RPE cells serving as a model for dry and wet type of AMD, respectively.Methods Autophagic cell death was induced by serum deprivation and H2O2 co‐treatment in ARPE‐19 and primary human RPE (hRPE) cells. Annexin‐V FITC/PI labelling was used to determine the cell death rate, while autophagy detection was achieved by Western blot quantification of LC3 II/LC3 I ratio. The clearance of autophagic dying cells by non‐professional and professional phagocytes was quantified using flow cytometry.Results An increasing percentage of dying RPE cells was observed in a time‐ and concentration dependent manner upon H2O2 treatment. Paralelly, an induction of autophagy could be detected within 2hrs of H2O2 treatment. Phagocytosis studies found autophagic dying cells to be efficiently and increasingly engulfed by both professional and non‐professional phagocytes over time.Conclusion The clearance of autophagic dying RPE cells can be used as a model for studying both dry and wet type of AMD in vitro, as well as for testing future pharmacological agents for treating this disease.