Journal Article

Role of glutamine synthetase in angiogenesis beyond glutamine synthesis

Wyns, Sabine, Zecchin, Annalisa, Gervasio, Francesco L., Lange, Christian, Treps, Lucas, Brüning, Ulrike, Cruys, Bert, Eelen, Guy, Hofkens, Johan, Saladino, Giorgio, Wu, Yi, Brepoels, Katleen, van Buul, Jaap D., Carmeliet, Peter, Chen, Rongyuan, Ramer, Leanne, Goveia, Jermaine, Ghesquière, Bart, Cantelmo, Anna Rita, Rocha, Susana, DeRan, Michael, Schoonjans, Luc, Souffreau, Joris, Dewerchin, Mieke, Morales-Rodriguez, Francisco, Li, Xuri, Huang, Hongling, Vandekeere, Saar, Vinckier, Stefan, Comitani, Federico, Kalucka, Joanna, Lamers, Wouter H., Liekens, Sandra, Wu, Xu, van Rijssel, Jos, Haustraete, Jurgen, Cubbon, Richard, Dubois, Charlotte, Jarugumilli, Gopala

2018

Overview

Glutamine synthetase, encoded by the gene GLUL , is an enzyme that converts glutamate and ammonia to glutamine. It is expressed by endothelial cells, but surprisingly shows negligible glutamine-synthesizing activity in these cells at physiological glutamine levels. Here we show in mice that genetic deletion of Glul in endothelial cells impairs vessel sprouting during vascular development, whereas pharmacological blockade of glutamine synthetase suppresses angiogenesis in ocular and inflammatory skin disease while only minimally affecting healthy adult quiescent endothelial cells. This relies on the inhibition of endothelial cell migration but not proliferation. Mechanistically we show that in human umbilical vein endothelial cells GLUL knockdown reduces membrane localization and activation of the GTPase RHOJ while activating other Rho GTPases and Rho kinase, thereby inducing actin stress fibres and impeding endothelial cell motility. Inhibition of Rho kinase rescues the defect in endothelial cell migration that is induced by GLUL knockdown. Notably, glutamine synthetase palmitoylates itself and interacts with RHOJ to sustain RHOJ palmitoylation, membrane localization and activation. These findings reveal that, in addition to the known formation of glutamine, the enzyme glutamine synthetase shows unknown activity in endothelial cell migration during pathological angiogenesis through RHOJ palmitoylation. The enzyme glutamine synthetase is active in endothelial cell migration during angiogenesis, through autopalmitoylation and the regulation of RHOJ signalling.

• Publisher: Nature Publishing Group UK,Nature Publishing Group
• Subject: 13/106 / 13/89 / 14/19 / 631/443/592/16 / 631/80/84/2341 / 64/60 / 82/51 / 96/63 / 96/95 / Actin / Actins - metabolism / Activation / Amino acids / Ammonia / Angiogenesis / Animals / Biosynthesis / Cell adhesion & migration / Cell migration / Cell Movement / Cell proliferation / Clonal deletion / Endothelial cells / Endothelial Cells - enzymology / Endothelial Cells - metabolism / Endothelial Cells - pathology / Endothelium / Enzymes / Female / Fibers / G proteins / Genes / Glutamate / Glutamate-ammonia ligase / Glutamate-Ammonia Ligase - deficiency / Glutamate-Ammonia Ligase - genetics / Glutamate-Ammonia Ligase - metabolism / Glutamate-Ammonia Ligase - physiology / Glutamine / Glutamine - biosynthesis / Glutamine synthetase / Guanosine triphosphatases / HEK293 Cells / Human Umbilical Vein Endothelial Cells - cytology / Human Umbilical Vein Endothelial Cells - enzymology / Human Umbilical Vein Endothelial Cells - metabolism / Humanities and Social Sciences / Humans / Kinases / Ligases / Lipoylation / Localization / Mice / multidisciplinary / Muscle proteins / Neovascularization / Neovascularization, Pathologic / Palmitic Acid - metabolism / Palmitoylation / Pharmacology / Physiology / Protein Processing, Post-Translational / Proteins / rho GTP-Binding Proteins - chemistry / rho GTP-Binding Proteins - metabolism / Rho-associated kinase / rho-Associated Kinases - metabolism / Science / Science (multidisciplinary) / Skin / Skin diseases / Stress Fibers - metabolism / Umbilical vein