Jacques-Antoine Haefliger1, Paolo Meda2 and Florian Alonso3 1Department of Medicine, Lausanne University Hospital, 1005 Lausanne, Switzerland 2Department of Cell Physiology and Metabolism, University of Geneva, Medical Center, 1211 Geneva, Switzerland 3Centre de Recherche Cardio-Thoracique de Bordeaux (INSERM U1045), Université de Bordeaux, 33076 Bordeaux, France Correspondence: florian.alonsou-bordeaux.fr

Connexins (Cxs) constitute a large family of transmembrane proteins that form gap junction channels, which enable the direct transfer of small signaling molecules from cell to cell. In blood vessels, Cx channels allow the endothelial cells (ECs) to respond to external and internal cues as a whole and, thus, contribute to the maintenance of vascular homeostasis. While the role of Cxs has been extensively studied in large arteries, a growing body of evidence suggests that they also play a role in the formation of microvascular networks. Since the formation of new blood vessels requires the coordinated response of ECs to external stimuli, endothelial Cxs may play an important role there. Recent studies in developmental and pathologic models reveal that EC Cxs regulate physiological and pathological angiogenesis through canonical and noncanonical functions, making these proteins potential therapeutic targets for the development of new strategies aimed at a better control of angiogenesis.