Exercise-induced angiogenesis is dependent on metabolically primed ATF3/4+ endothelial cells

Exercise is a powerful driver of physiological angiogenesis during adulthood, but the mechanisms of exercise-induced vascular expansion are poorly understood. We explored endothelial heterogeneity in skeletal muscle and identified two capillary muscle endothelial cells (mEC) populations which are characterized by differential expression of ATF3/4. Spatial mapping showed that ATF3/4 + mECs are enriched in red oxidative muscle areas while ATF3/4 low ECs lie adjacent to white glycolytic fibers. In vitro and in vivo experiments revealed that red ATF3/4 + mECs are more angiogenic when compared to white ATF3/4 low mECs. Mechanistically, ATF3/4 in mECs control genes involved in amino acid uptake and metabolism and metabolically prime red (ATF3/4 + ) mECs for angiogenesis. As a consequence, supplementation of non-essential amino acids and overexpression of ATF4 increased proliferation of white mECs. Finally, deleting Atf4 in ECs impaired exercise-induced angiogenesis. Our findings illustrate that spatial metabolic angiodiversity determines the angiogenic potential of muscle ECs. mRNA from sorted skeletal muscle (glycolytic or oxidative) endothelial cells (mECs) (CD31+CD45-) of WT and ATF4-/- mice (EC specific KO). 5 replicates per sample.