New Q(ues) to keep blood vessels growing

Abstract

How endothelial cells adapt their metabolism to the rising energy and biomass demands of sprouting vessels is an exciting field of research in vascular biology with numerous open questions. Two new studies published in this issue of The EMBO Journal now show the importance of glutamine in endothelial metabolism, required to sustain endothelial cell proliferation and vascular expansion. These results provide insight into how endothelial cells selectively use nutrients for energy and biomass production and illuminate new levels of regulation of the angiogenic process.See also: H Huang et al (August 2017) andB Kim et al (August 2017)Endothelial cells (ECs) have special functions—functions that are critical for development and homeostasis, but also cause disease if not properly controlled. As inner lining of the blood vasculature, ECs provide nutrients and oxygen for tissues and remove waste products that result from the breakdown of these metabolic fuels. They also orchestrate the growth of the vasculature, a process referred to as angiogenesis. Activated by growth factors that are secreted from nutrient‐ and oxygen‐deprived tissues (e.g. VEGF), ECs sprout, migrate and proliferate to form new vessel branches. Only recently it has been recognized that such endothelial behaviour is not only dependent on growth factor‐induced signal transduction but also on endothelial metabolic state (Potente & Carmeliet, 2017). This is because the angiogenic process is metabolically demanding. ECs need nutrients and energy for migration as well as for the synthesis of cellular building blocks (nucleotides, amino acids, lipids) that are required for growth and proliferation. As a result, ECs must switch from a metabolic state that maintains basic cellular processes to a state of increased energy and biomass production. However, how ECs use their metabolic machinery to fulfil these requirements is poorly understood. Two studies in this issue shed light on this question by …