Endothelial Cell–Specific Deletion of P2Y ₂ Receptor Promotes Plaque Stability in Atherosclerosis-Susceptible ApoE-Null Mice

Abstract

Objective Nucleotide P2Y2 receptor (P2Y2R) contributes to vascular inflammation by increasing vascular cell adhesion molecule (VCAM)-1 expression in endothelial cells (EC), and global P2Y2R deficiency prevents fatty streak formation in ApoE−/− mice. Since P2Y2R is ubiquitously expressed in vascular cells, we investigated the contribution of endothelial P2Y2R in the pathogenesis of atherosclerosis. Approach and Results EC-specific P2Y2R-deficient mice were generated by breeding VEcadherin5-Cre mice with the P2Y2R “floxed” mice. Endothelial P2Y2R deficiency reduced eNOS activity and significantly altered ATP-and UTP-induced vasorelaxation without affecting vasodilatory responses to acetylcholine. Telemetric blood pressure and echocardiography measurements indicated that EC-specific P2Y2R-deficient mice did not develop hypertension. We investigated the role of endothelial P2Y2R in the development of atherosclerotic lesions by crossing the EC-specific P2Y2R knockout mice onto an ApoE−/− background and evaluated lesion development after feeding a standard chow diet for 25 weeks. Histopathological examination demonstrated reduced atherosclerotic lesions in the aortic sinus and entire aorta, decreased macrophage infiltration and increased smooth muscle cell and collagen content leading to the formation of a subendothelial fibrous cap in EC-specific P2Y2R-deficient ApoE−/− mice. Expression and proteolytic activity of matrix metalloproteinase (MMP)-2 was significantly reduced in atherosclerotic lesions from EC-specific P2Y2R-deficient ApoE−/− mice. Furthermore, EC-specific P2Y2R deficiency inhibited NO production leading to significant increase in SMC migration out of aortic explants. Conclusions EC-specific P2Y2R-deficiency reduces atherosclerotic burden and promotes plaque stability in ApoE−/− mice through impaired macrophage infiltration acting together with reduced MMP-2 activity and increased SMC migration.

P2Y Purinergic Receptors, Endothelial Dysfunction, and Cardiovascular Diseases

“…Additional indications of TLR9 activity were evident, probably acting as a DAMP (damage-associated molecular pattern) response [ 80 ]. Other evidence supports the pro-inflammatory phenotype of P2Y12 in atherosclerosis, as P2Y2 null mice are protected against the disease [ 81 ].…”

“…ATP, being released from EC and other cell type, is pro-inflammatory and instigates leukocyte infiltration via P2Y2 receptors. P2Y2-null mice show blunted responses on a high-fat diet, gain less weight, and have better insulin sensitivity and lower cholesterol levels [ 81 ]. Adipose tissue is highly vascularized, and some of the P2Y2 action probably spills over to effects on EC P2Y2.…”

Endothelial Functions

“…Chen et al 52 demonstrated that endothelium-specific deletion of P2Y 2 receptor exerted protective effects on plaque stabilization by promoting fibrous cap formation in an atherosclerotic mouse model. Considering that the endothelial cell-specific P2Y 2 receptor-deficient mice showed decreased nucleotidemediated but preserved acetylcholine-induced endotheliumdependent relaxation of the aorta without causing systemic hypertension, endothelial P2Y 2 receptor may be a promising therapeutic target for atherosclerotic cardiovascular diseases.…”

P2 Receptors as Therapeutic Targets in the Salivary Gland: From Physiology to Dysfunction

“…The P2Y 2 R also mediates the proprotein convertase furin-dependent activation of metalloproteases, i.e., a disintegrin and metalloproteinase 10 and 17 (ADAM10/17), to cleave transmembrane proteins , thereby releasing EGFR/ERB ligands that promote Src-independent EGFR activation (Ratchford et al, 2010). These diverse P2Y 2 R signaling pathways have been implicated in a number of pathologies, including Alzheimer's disease (Ajit et al, 2014), cardiovascular disease (Chen et al, 2017), cancer , SS (Woods et al, 2018), and hantavirus cardiopulmonary syndrome (Bondu et al, 2018), as well as processes such as wound healing and tissue regeneration .…”