Expressing data from endothelial cells overexpressing the purinergic receptor P2Y2. Expressing data from endothelial cells overexpressing the purinergic receptor P2Y2

Purinergic P2 receptors are critical regulators of several functions within the vascular system, including platelet aggregation, vascular inflammation and vascular tone. A role for ATP release and P2Y receptors in angiogenesis has been implicated, however, the involvement of purinergic signalling in endothelial sprouting and vascular growth remains poorly understood. Here, we demonstrate that blood vessel growth is controlled by P2Y2 receptors. Inhibition of P2Y2 using a selective antagonist or modulation of P2Y2 receptor expression significantly influenced sprouting and vascular tube formation. Mechanistically, overexpression of P2Y2 in endothelial cells resulted in increased expression of the pro-angiogenic molecules CXCR4, CD34 and angiopoietin-2, while expression of Tie2 and VEGFR-2 decreased. Interestingly, elevated P2Y2 expression caused constitutive phosphorylation of ERK1/2 and VEGFR-2. However, stimulation of cells with the P2Y2 agonist UTP did not influence sprouting unless P2Y2 was constitutively expressed, indicating that enhanced receptor expression, and not activation, is the primary trigger for angiogenesis. Our data suggest that P2Y2 receptors have an essential function in angiogenesis through cross-talk of P2Y2 and VEGFR-2 and that P2Y2 may represent a therapeutic target to regulate blood vessel growth. Overall design: 4 HUVEC samples total, two samples per group, control and treatment are represented with two biological replicates (= two different batches of cells)