The retinal pigment epithelium (RPE) is a monolayer of pigmented cells between the choroid
and the retina. RPE dysfunction underlies many retinal degenerative diseases, including
age-related macular degeneration, the leading cause of age-related blindness. To perform
its various functions in nutrient transport, phagocytosis of the outer segment, and cytokine
secretion, the RPE relies on an active energy metabolism. We previously reported that
human RPE cells prefer proline as a nutrient and transport proline-derived metabolites to the …