P2Y1 and P2Y13 purinergic receptors mediate Ca2+ signaling and proliferative responses in pulmonary artery vasa vasorum endothelial cells

Abstract

Extracellular ATP and ADP exhibit potent angiogenic effects on pulmonary artery adventitial vasa vasorum endothelial cells (VVEC), however the mechanisms of nucleotide-mediated angiogenesis remain not fully elucidated. This study was undertaken to delineate the purinergic receptor subtypes involved in extracellular nucleotide-mediated Ca2+ signaling and mitogenic responses in VVEC. Stimulation of VVEC with ATP resulted in the elevation of intracellular Ca2+ ([Ca2+]i) via Ca2+influx through plasma membrane channels as well as Ca2+ mobilization from intracellular stores; moreover, simultaneous Ca2+ responses were observed in both cytosolic and nuclear compartments. An increase in [Ca2+]i was observed in response to some P2, but not P1 purinergic receptor agonists. Using RT-PCR, we identified mRNA for the P2Y1,2,4,13,14, P2X2,5,7 and A1,2b,3 purinergic receptors in VVEC. Preincubation of VVEC with P2Y1 selective antagonist, MRS2179 and P2Y13 selective antagonist, MRS2211, as well as with Pertussis toxin, attenuated at varying degrees, agonist-induced intracellular Ca2+ responses and activation of ERK1/2, Akt and S6 ribosomal protein, indicating that P2Y1 and P2Y13 receptors play a predominant role in VVEC growth responses. Together, our findings suggest that P2Y1 and P2Y13 receptors may represent novel and specific targets for treatment of pathologic vascular remodeling involving vasa vasorum expansion.