Retinal lipid and glucose metabolism dictates angiogenesis through the lipid sensor Ffar1.
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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. |
Year of Publication | 2016
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Journal | Nat Med
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Volume | 22
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Issue | 4
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Pages | 439-45
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Date Published | 2016 Apr
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ISSN | 1546-170X
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URL | |
DOI | 10.1038/nm.4059
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PubMed ID | 26974308
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PubMed Central ID | PMC4823176
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Grant list | EY017017 / EY / NEI NIH HHS / United States
R01 EY017017 / EY / NEI NIH HHS / United States
EY024963 / EY / NEI NIH HHS / United States
R01 EY022275 / EY / NEI NIH HHS / United States
EY11254 / EY / NEI NIH HHS / United States
EY022275 / EY / NEI NIH HHS / United States
P01 HD18655 / HD / NICHD NIH HHS / United States
P30 HD018655 / HD / NICHD NIH HHS / United States
EY024864 / EY / NEI NIH HHS / United States
R01 EY024963 / EY / NEI NIH HHS / United States
U54 HD090255 / HD / NICHD NIH HHS / United States
143077 / Canadian Institutes of Health Research / Canada
R24 EY024864 / EY / NEI NIH HHS / United States
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