The Vascular Endothelial Growth Factor-Induced Disruption of Gap Junctions Is Relayed by an Autocrine Communication via ATP Release in Coronary Capillary Endothelium

• Published in: Annals of the New York Academy of Sciences Vol. 1030; no. 1; pp. 14 - 27
• Main Author: THURINGER, DOMINIQUE
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-12-2004
• Subjects: Adenosine Triphosphate - metabolism; Animals; ATP release; Ca2+ waves; Capillaries - metabolism; Cell Communication - physiology; Cells, Cultured; connexin; Coronary Vessels - cytology; Coronary Vessels - metabolism; Epithelium - metabolism; Gap Junctions - physiology; inflammatory agents; mechanical stimulus; Phosphorylation; Rats; signal transduction pathways; Tyrosine - metabolism; Vascular Endothelial Growth Factor A - physiology
• ISSN: 0077-8923; 1749-6632
• DOI: 10.1196/annals.1329.003

: Little is known concerning how the coordination of Ca2+ signaling aids in capillary endothelial cell (CEC) functions, such as microvascular permeability and angiogenesis. Previous reports support the major involvement of gap junction (GJ) channels. However, the cell‐to‐cell communication may not be straightforward, especially if we consider the participation of active molecules released by CEC. In this study, short‐term effects of vascular endothelial growth factor (VEGF‐165) were compared with those of bradykinin (BK) on gap junction coupling (GJC) and remodeling of connexin‐43 (Cx43) and then analyzed for intercellular Ca2+ signal in primary cultures of coronary CEC. Dye‐coupling experiments revealed that BK or VEGF completely blocked GJC. These effects correlated with the rapid internalization of Cx43 and its tyrosine phosphorylation in part via the phosphatidylinositol 3‐kinase/Akt pathway. GJC slowly recovered with BK but not with VEGF in the following hour. In control conditions, mechanical stimulation of a single cell within a confluent monolayer triggered an intercellular Ca2+ wave that was partially inhibited by GJC blockers or purinergic inhibitors. No wave propagation was observed after blockage of both GJC and purinergic receptors. Cell treatment with VEGF also reduced propagation of the Ca2+ wave, which was totally prevented by applying a purinergic receptor antagonist but not with a GJC blocker. That excludes purine efflux through Cx hemichannels. We conclude that VEGF‐induced disruption of GJC via Cx43 remodeling is relayed by an autocrine communication via secretion of ATP to preserve intercellular Ca2+ signaling in capillary endothelium.