Author:

Keywords:

Science & Technology, Multidisciplinary Sciences, Science & Technology - Other Topics, GROWTH-FACTOR, METABOLISM, OXIDATION, TUMOR, ANGIOGENESIS, GLYCOLYSIS, CULTURE, KINASE, POOLS, Acetic Acid, Adenosine Triphosphate, Animals, Blood Vessels, Carbon, Carnitine O-Palmitoyltransferase, Cell Line, Tumor, Cell Proliferation, Citric Acid Cycle, DNA, Disease Models, Animal, Endothelial Cells, Fatty Acids, Gene Silencing, Glucose, Human Umbilical Vein Endothelial Cells, Humans, Mice, Neovascularization, Pathologic, Nucleotides, Oxidation-Reduction, Retinopathy of Prematurity, General Science & Technology

Abstract:

The metabolism of endothelial cells during vessel sprouting remains poorly studied. Here we report that endothelial loss of CPT1A, a rate-limiting enzyme of fatty acid oxidation (FAO), causes vascular sprouting defects due to impaired proliferation, not migration, of human and murine endothelial cells. Reduction of FAO in endothelial cells did not cause energy depletion or disturb redox homeostasis, but impaired de novo nucleotide synthesis for DNA replication. Isotope labelling studies in control endothelial cells showed that fatty acid carbons substantially replenished the Krebs cycle, and were incorporated into aspartate (a nucleotide precursor), uridine monophosphate (a precursor of pyrimidine nucleoside triphosphates) and DNA. CPT1A silencing reduced these processes and depleted endothelial cell stores of aspartate and deoxyribonucleoside triphosphates. Acetate (metabolized to acetyl-CoA, thereby substituting for the depleted FAO-derived acetyl-CoA) or a nucleoside mix rescued the phenotype of CPT1A-silenced endothelial cells. Finally, CPT1 blockade inhibited pathological ocular angiogenesis in mice, suggesting a novel strategy for blocking angiogenesis.