Related Experiment Video
Updated: Aug 21, 2026
Improved Lipofuscin Models and Quantification of Outer Segment Phagocytosis Capacity in Highly Polarized Human Retinal Pigment Epithelial Cultures
Published on: April 14, 2023
ADORA2A activation restores lysosomal function and photoreceptor outer segment degradation in stressed retinal
Daodian Tao1, Daiying Zhou2, Mingjuan Wu3
1Department of Ophthalmology, Jinhua Municipal Central Hospital, Jinhua, China.
Background:
Age-related macular degeneration (AMD) involves early retinal pigment epithelium (RPE) dysfunction and impaired processing of photoreceptor outer segments (POS). We investigated whether ADORA2A regulates post-ingestive POS handling and lysosomal recovery under AMD-relevant stress.
Methods:
A2E-stressed ARPE-19 cells, primary porcine RPE cells, and a sodium iodate-induced mouse model were studied. ADORA2A was activated with CGS21680 and inhibited with ZM241385. POS handling, LC3B/Rubicon association with POS, lysosomal function, Rubicon depletion, chronic stress phenotypes, and retinal protection were assessed.
Results:
A2E increased ADORA2A expression while preserving receptor-dependent cAMP responsiveness. CGS21680 had modest effects on early POS binding and uptake but enhanced post-ingestive POS clearance and rhodopsin degradation; these effects were attenuated by ZM241385 and ADORA2A knockdown. CGS21680 increased LC3B and Rubicon association with POS-containing structures, improved lysosomal acidification, and restored DQ Green BSA processing, Cathepsin D activity, and V-ATPase-associated assembly. Bafilomycin A1 increased LC3-II and p62 accumulation and impaired CGS21680-associated POS clearance, supporting lysosome-dependent turnover. Rubicon depletion attenuated CGS21680-associated improvements in POS clearance and lysosomal acidification. CGS21680 also reduced chronic stress-associated autofluorescence, oxidative stress, apoptosis, and junctional disruption. These protective effects were reproduced in primary RPE cells. In sodium iodate-injured mice, CGS21680 preserved outer retinal structure, reduced FITC-BSA leakage, improved electroretinographic responses, and was accompanied by increased CREB phosphorylation and recovery of Cathepsin D proteolytic competence.
Conclusion:
ADORA2A activation promotes Rubicon-associated, lysosome-dependent LC3 processing of internalized POS and restores lysosomal degradative competence, supporting ADORA2A as a potential therapeutic target for early AMD.
