Oxidative Stress and Dysfunctional Intracellular Traffic Linked to an Unhealthy Diet Results in Impaired Cargo Transport in the Retinal Pigment Epithelium (RPE)

Mol Nutr Food Res. 2019 Aug;63(15):e1800951. doi: 10.1002/mnfr.201800951. Epub 2019 Mar 20.

Abstract

Scope: Oxidative stress and dysregulated intracellular trafficking are associated with an unhealthy diet which underlies pathology. Here, these effects on photoreceptor outer segment (POS) trafficking in the retinal pigment epithelium (RPE), a major pathway of disease underlying irreversible sight-loss, are studied.

Methods and results: POS trafficking is studied in ARPE-19 cells using an algorithm-based quantification of confocal-immunofluorescence data supported by ultrastructural studies. It is shown that although POS are tightly regulated and trafficked via Rab5, Rab7 vesicles, LAMP1/2 lysosomes and LC3b-autophagosomes, there is also a considerable degree of variation and flexibility in this process. Treatment with H2 O2 and bafilomycin A1 reveals that oxidative stress and dysregulated autophagy target intracellular compartments and trafficking in strikingly different ways. These effects appear limited to POS-containing vesicles, suggesting a cargo-specific effect.

Conclusion: The findings offer insights into how RPE cells cope with stress, and how mechanisms influencing POS transport/degradation can have different outcomes in the senescent retina. These shed new light on cellular processes underlying retinopathies such as age-related macular degeneration. The discoveries reveal how diet and nutrition can cause fundamental alterations at a cellular level, thus contributing to a better understanding of the diet-disease axis.

Keywords: cargo trafficking; oxidative stress; phagosome and autophagy-lysosomal pathways; retinal pigment epithelium.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Autophagosomes / metabolism
  • Biological Transport
  • Cell Line
  • Diet / adverse effects*
  • Humans
  • Hydrogen Peroxide / pharmacology
  • Intracellular Space / metabolism
  • Lysosomal-Associated Membrane Protein 2 / metabolism
  • Lysosome-Associated Membrane Glycoproteins / metabolism
  • Macrolides / pharmacology
  • Microtubule-Associated Proteins / metabolism
  • Oxidative Stress* / drug effects
  • Retinal Photoreceptor Cell Outer Segment / metabolism
  • Retinal Pigment Epithelium / metabolism*
  • Retinal Pigment Epithelium / pathology
  • rab GTP-Binding Proteins / metabolism
  • rab5 GTP-Binding Proteins / metabolism

Substances

  • LAMP1 protein, human
  • LAMP2 protein, human
  • Lysosomal-Associated Membrane Protein 2
  • Lysosome-Associated Membrane Glycoproteins
  • MAP1LC3B protein, human
  • Macrolides
  • Microtubule-Associated Proteins
  • rab7 protein
  • bafilomycin A1
  • Hydrogen Peroxide
  • RAB5C protein, human
  • rab GTP-Binding Proteins
  • rab5 GTP-Binding Proteins