Age-related macular degeneration (AMD) is the leading cause of blindness among older adults. It has been suggested that mitochondrial defects in the retinal pigment epithelium (RPE) underlies AMD pathology. To test this idea, we developed primary cultures of RPE to ask whether RPE from donors with AMD differ in their metabolic profile compared with healthy age-matched donors. Analysis of gene expression, protein content, and RPE function showed that these cultured cells replicated many of the cardinal features of RPE in vivo. Using the Seahorse Extracellular Flux Analyzer to measure bioenergetics, we observed RPE from donors with AMD exhibited reduced mitochondrial and glycolytic function compared with healthy donors. RPE from AMD donors were also more resistant to oxidative inactivation of these two energy-producing pathways and were less susceptible to oxidation-induced cell death compared with cells from healthy donors. Investigation of the potential mechanism responsible for differences in bioenergetics and resistance to oxidative stress showed RPE from AMD donors had increased PGC1α protein as well as differential expression of multiple genes in response to an oxidative challenge. Based on our data, we propose that cultured RPE from donors phenotyped for the presence or absence of AMD provides an excellent model system for studying “AMD in a dish”. Our results are consistent with the ideas that (i) a bioenergetics crisis in the RPE contributes to AMD pathology, and (ii) the diseased environment in vivo causes changes in the cellular profile that are retained in vitro.
Bibliographical noteFunding Information:
This work was supported by the Elaine and Robert Larson Endowed Vision Research Chair (to DAF); National Institutes of Health/ National Institute of Aging (T32-AG29796 to MRT) and National Eye Institute (R01 EY026012 to DAF); Beckman Initiative for Macular Research (#1303); Foundation Fighting Blindness (TA-NMT-0613-0620-UMN); Regenerative Medicine Minnesota (2015-5337);an anonymous benefactor for Macular Degeneration Research; the Lindsay Family Foundation; Minnesota Lions Vision Foundation; an unrestricted grant from Research to Prevent Blindness to the Department of Ophthalmology and Visual Neurosciences. None of the funding agencies had a role in study design, in the collection, analysis and interpretation of data, in writing the manuscript, or in the decision to submit the manuscript for publication.
- 6 max) Age-related macular degeneration
- Glycolytic function
- Mitochondrial function
- Oxidative stress
- Retinal pigment epithelium