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Endothelial cells (ECs) are highly glycolytic, but whether they generate glycolytic intermediates via gluconeogenesis (GNG) in glucose-deprived conditions remains unknown. Here, we report that glucose-deprived ECs upregulate the GNG enzyme PCK2 and rely on a PCK2-dependent truncated GNG, whereby lactate and glutamine are used for the synthesis of lower glycolytic intermediates that enter the serine and glycerophospholipid biosynthesis pathways, which can play key roles in redox homeostasis and phospholipid synthesis, respectively. Unexpectedly, however, even in normal glucose conditions, and independent of its enzymatic activity, PCK2 silencing perturbs proteostasis, beyond its traditional GNG role. Indeed, PCK2-silenced ECs have an impaired unfolded protein response, leading to accumulation of misfolded proteins, which due to defective proteasomes and impaired autophagy, results in the accumulation of protein aggregates in lysosomes and EC demise. Ultimately, loss of PCK2 in ECs impaired vessel sprouting. This study identifies a role for PCK2 in proteostasis beyond GNG., (© 2024. The Author(s).)

Endothelial cells (ECs) are more than inert blood vessel lining material. Instead, they are active players in the formation of new blood vessels (angiogenesis) both in health and (life-threatening) diseases. Recently, a new concept arose by which EC metabolism drives angiogenesis in parallel to well-established angiogenic growth factors (e.g., vascular endothelial growth factor). 6-Phosphofructo-2-kinase/fructose-2,6-bisphosphatase-3-driven glycolysis generates energy to sustain competitive behavior of the ECs at the tip of a growing vessel sprout, whereas carnitine palmitoyltransferase 1a-controlled fatty acid oxidation regulates nucleotide synthesis and proliferation of ECs in the stalk of the sprout. To maintain vascular homeostasis, ECs rely on an intricate metabolic wiring characterized by intracellular compartmentalization, use metabolites for epigenetic regulation of EC subtype differentiation, crosstalk through metabolite release with other cell types, and exhibit EC subtype-specific metabolic traits. Importantly, maladaptation of EC metabolism contributes to vascular disorders, through EC dysfunction or excess angiogenesis, and presents new opportunities for anti-angiogenic strategies. Here we provide a comprehensive overview of established as well as newly uncovered aspects of EC metabolism., (Copyright © 2018 the American Physiological Society.)

The vasculature of the bone marrow remains poorly characterized, yet crucial to maintain hematopoiesis and retain stem cells in a quiescent state. A recent study by Itkin et al. (2016) in Nature reports how vascular barrier integrity and endothelial cell metabolism regulate hematopoietic stem cell quiescence and leukocyte trafficking., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Tumour angiogenesis has long been recognised as a target for anti-cancer therapy. The current approach of inhibiting the VEGF pathway has shown benefit in the clinic, though less than anticipated. We recently documented that glycolytic metabolism in endothelial cells (ECs) fuels angiogenesis, rendering it a possible target for inhibiting vascular growth in pathological conditions. More recently, we reported that the oxidation of fatty acids (FA) is irreplaceable for EC proliferation by providing carbons for de novo nucleotide synthesis. Furthermore, ECs are rather unique in this respect, creating novel therapeutic opportunities. Here, we review and compare the current understanding of FA utilisation in ECs and tumour cells (TCs)., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Tumour tissue is characterised by fluctuating oxygen concentrations, decreased nutrient supply, and acidic pH. The primarily glycolytic metabolism of tumour cells contributes to this, with increased glucose consumption and increased lactate secretion. Endothelial cells are particularly challenged when recruited towards the tumour metabolic environment. They are required to proliferate and form functional networks in order to establish continuous blood flow. Considering that deregulated metabolism is an emerging hallmark of cancer and target of tumour therapy, it is of importance to incorporate the current knowledge about how the tumour metabolic environment, as a therapy target, can affect endothelial cell metabolism and the angiogenic response. Recent studies have shown differences in metabolic pathways in endothelial cells compared with other normal or tumour tissues. Therefore, we have reviewed relevant literature on endothelial metabolism and the response to angiogenic activation in conditions of metabolic stress.