Formation of Lipofuscin-Like Autofluorescent Granules in the Retinal Pigment Epithelium Requires Lysosome Dysfunction.

ABSTRACT:

Purpose

We aim to characterize the pathways required for autofluorescent granule (AFG) formation by RPE cells using cultured monolayers.

Methods

We fed RPE monolayers in culture with a single pulse of photoreceptor outer segments (POS). After 24 hours the cells started accumulating AFGs that were comparable to lipofuscin in vivo. Using this model, we used a variety of light and electron microscopical techniques, flow cytometry and Western blot to analyze the formation of AFGs. We also generated a mutant RPE line lacking cathepsin D by gene editing.

Results

AFGs seem to derive from incompletely digested POS-containing phagosomes and after 3 days are surrounded by a single membrane positive for lysosome markers. We show by various methods that lysosome-phagosome fusion

SUBMITTER: Escrevente C 

PROVIDER: S-EPMC8322709 | biostudies-literature | 2021 Jul

REPOSITORIES: biostudies-literature