Retinal lipid and glucose metabolism dictates angiogenesis through the lipid sensor Ffar1

JS Joyal, Y Sun, ML Gantner, Z Shao, LP Evans… - Nature medicine, 2016 - nature.com
JS Joyal, Y Sun, ML Gantner, Z Shao, LP Evans, N Saba, T Fredrick, S Burnim, JS Kim
Nature medicine, 2016nature.com
Tissues with high metabolic rates often use lipids, as well as glucose, for energy, conferring
a survival advantage during feast and famine. Current dogma suggests that high-energy–
consuming photoreceptors depend on glucose,. Here we show that the retina also uses fatty
acid β-oxidation for energy. Moreover, we identify a lipid sensor, free fatty acid receptor 1
(Ffar1), that curbs glucose uptake when fatty acids are available. Very-low-density
lipoprotein receptor (Vldlr), which is present in photoreceptors and is expressed in other …
Abstract
Tissues with high metabolic rates often use lipids, as well as glucose, for energy, conferring a survival advantage during feast and famine. Current dogma suggests that high-energy–consuming photoreceptors depend on glucose,. Here we show that the retina also uses fatty acid β-oxidation for energy. Moreover, we identify a lipid sensor, free fatty acid receptor 1 (Ffar1), that curbs glucose uptake when fatty acids are available. Very-low-density lipoprotein receptor (Vldlr), which is present in photoreceptors and is expressed in other tissues with a high metabolic rate, facilitates the uptake of triglyceride-derived fatty acid,. In the retinas of Vldlr−/− mice with low fatty acid uptake but high circulating lipid levels, we found that Ffar1 suppresses expression of the glucose transporter Glut1. Impaired glucose entry into photoreceptors results in a dual (lipid and glucose) fuel shortage and a reduction in the levels of the Krebs cycle intermediate α-ketoglutarate (α-KG). Low α-KG levels promotes stabilization of hypoxia-induced factor 1a (Hif1a) and secretion of vascular endothelial growth factor A (Vegfa) by starved Vldlr−/− photoreceptors, leading to neovascularization. The aberrant vessels in the Vldlr−/− retinas, which invade normally avascular photoreceptors, are reminiscent of the vascular defects in retinal angiomatous proliferation, a subset of neovascular age-related macular degeneration (AMD), which is associated with high vitreous VEGFA levels in humans. Dysregulated lipid and glucose photoreceptor energy metabolism may therefore be a driving force in macular telangiectasia, neovascular AMD and other retinal diseases.
nature.com