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 cell (mEC) populations that 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 with 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.

运动是成年期生理性血管生成的强大驱动力，但运动引起的血管扩张的机制却知之甚少。我们探索了骨骼肌中的内皮异质性，并确定了两个以 ATF3/4 差异表达为特征的毛细血管内皮细胞 (mEC) 群。空间映射显示 ATF3/4 ⁺ mECs 富含红色氧化肌肉区域，而 ATF3/4^低ECs 位于白色糖酵解纤维附近。体外和体内实验表明，与白色 ATF3/4^{低相比，红色 ATF3/4 +} mEC 更具血管生成性mEC。从机制上讲，mECs 中的 ATF3/4 控制参与氨基酸摄取和代谢的基因，并在代谢上引发红色 (ATF3/4 ⁺ ) mECs 用于血管生成。因此，补充非必需氨基酸和过表达 ATF4 增加了白色 mEC 的增殖。最后，删除ECs 中的Atf4会损害运动诱导的血管生成。我们的研究结果表明，空间代谢血管多样性决定了肌肉 ECs 的血管生成潜力。