Nucleotide Receptors Involved in UTP-Induced Rat Arterial Smooth Muscle Cell Migration

Abstract

Abstract-Many factors have been shown to be involved in the development of hyperplasic lesions of vessels, but the role of extracellular nucleotides remains largely unknown. The presence of P2Y and P2X nucleotide receptors on arterial endothelial and smooth muscle cells suggests a potential role for nucleotides in the vessel pathophysiology. Although the role of P2X in physiology of vessels is well documented, that of P2Y is not completely understood. We recently demonstrated that extracellular nucleotides, and particularly UTP, induced migration of cultured arterial smooth muscle cells (ASMCs). This migration is dependent on osteopontin expression and involves the Rho and mitogen-activated protein (MAP) kinase pathways. An important question is to determine the specific role of the different P2Y receptors of rat ASMCs in the UTP-induced migration process. Therefore, we first quantified mRNA levels of P2Y 2 , P2Y 4 , and P2Y 6 nucleotide receptors in cultured rat ASMCs by a competitive RT-PCR approach and demonstrated that P2Y 2 is the most highly expressed among these receptors potentially involved in the UTP-mediated response. In addition to UTP, UDP also induced ASMC migration even when UTP regeneration was inhibited, suggesting the involvement of UDP receptor P2Y 6 . Moreover, suramin, a specific antagonist of rat P2Y 2 receptor, acted as an inhibitor of UTP-induced migration. Taken together, these results suggest a prominent role for the UTP receptor, P2Y 2 , and for the UDP receptor, Key Words: purinergic receptors Ⅲ migration Ⅲ UTP Ⅲ smooth muscle cells T he important role of arterial smooth muscle cell (ASMC) migration and proliferation in arterial hyperplasia is well documented in experimental models for atherosclerosis and restenosis. 1 Although proliferation can be easily demonstrated in arterial injury models, evidence for in vivo ASMC migration is suggested only by the presence of these cells in the intima.Many factors have been shown to be involved in the development of hyperplasic lesions of vessels. 2 Among these, the role of extracellular nucleotides remains largely unknown. Two families of receptors have been identified for these compounds: inotropic P2X receptors and metabotropic P2Y receptors. The presence of P2Y and P2X receptors on endothelial and ASMCs suggests a potential role for nucleotides in the arterial pathophysiology. Although the role of P2X receptors in vasomotoricity of vessels is well documented, that of P2Y receptors in the vessel wall is still under investigation.Several studies have shown that ATP and UTP binding to P2Y G protein-coupled receptors mediates ASMC activation, 3 cell-cycle progression, 4 and cell proliferation. 5,6 Moreover, we recently demonstrated that UTP induces ASMC migration and that this migration is dependent on osteopontin expression and involves the Rho and mitogen-activated protein (MAP) kinase pathways. 7 The overexpression of the ATP/UTP P2Y 2 receptor in ASMCs of rat aortic intimal lesion 8 and in ASMCs of human coronary atherosclerotic/restenotic ...

P2X1 receptor-mediated inhibition of the proliferation of human coronary smooth muscle cells involving the transcription factor NR4A1

“…α,β-methylene-ATP inhibited with a halfmaximal concentration of about 0.1 μM the migration of the cells. P2Y receptors including the P2Y 2 , P2Y 6 , and P2Y 12 subtypes mediate the opposite effect-an increase in migration [54][55][56][57][58][59]. Migration facilitated by the activation of P2Y 2 receptors involved the ERK1/2 as well as the arrestin2 pathway [54,58].…”

ADP Stimulates Human Endothelial Cell Migration via P2Y 1 Nucleotide Receptor–Mediated Mitogen-Activated Protein Kinase Pathways

“…Extracellular nucleotide stimulation of cell migration has received increasing attention; however, previous studies in this field have focused on the ATP-and UTP-sensitive P2Y 2 receptor in different cells, including vascular smooth muscle cells, 8 endothelial cells, 9 astrocytes, 23 and more recently neutrophils. 24 Because ADP shares different receptors with ATP/UTP, 5 it remained to be determined whether ADP receptors are equally important in cell migration.…”

“…7 It also has been shown that stimulation of the P2Y 2 receptor by ATP or UTP in cultured vascular endothelial cells or smooth muscle cells leads to cell migration. 8,9 Although much information has been gained regarding the roles of ATP/UTP-sensitive P2Y 2 receptor in the vasculature, relatively little is known about the roles for ADP-preferring receptors (P2Y 1 , P2Y 12 and P2Y 13 ), especially in the endothelium. 5 Given the fact that ADP is the major nucleotide released from activated platelets 5,10 and because the ADP receptor antagonist clopidogrel (Plavix; sanofi-aventis) has been widely used in different cardiovascular and surgical events as a new antithrombotic drug, 11 it is important to understand how ADP affects cellular functions of the endothelium via 1 or more of its receptors.…”

UTP Induces Osteopontin Expression through a Coordinate Action of NFκB, Activator Protein-1, and Upstream Stimulatory Factor in Arterial Smooth Muscle Cells

“…Moreover, nucleotides also modulate contraction, proliferation, and migration of vascular SMCs (11). They act through G proteincoupled P2Y receptors (12) and activate phospholipase C, resulting in elevated levels of intracellular free Ca 2ϩ and activation of PKC. In addition, they induce ROS production through NAD(P)H oxidase (13).…”