P2Y ₆ Deficiency Limits Vascular Inflammation and Atherosclerosis in Mice

Abstract

Objective-Nucleotides such as ATP, ADP, UTP, and UDP serve as proinflammatory danger signals via purinergic receptors on their release to the extracellular space by activated or dying cells. UDP binds to the purinergic receptor Y 6 (P2Y 6 ) and propagates vascular inflammation by inducing the expression of chemokines such as monocyte chemoattractant protein 1, interleukin-8, or its mouse homologsCCL1 (chemokine [C-C motif] ligand 1)/keratinocyte chemokine, CXCL2 (chemokine [C-X-C motif] ligand 2)/macrophage inflammatory protein 2, and CXCL5 (chemokine [C-X-C motif] ligand 5)/LIX, and adhesion molecules such as vascular cell adhesion molecule 1 and intercellular cell adhesion molecule 1. Thus, P2Y 6 contributes to leukocyte recruitment and inflammation in conditions such as allergic asthma or sepsis. Because atherosclerosis is a chronic inflammatory disease driven by leukocyte recruitment to the vessel wall, we hypothesized a role of P2Y 6 in atherogenesis. Approach and Results-Intraperitoneal stimulation of wild-type mice with UDP induced rolling and adhesion of leukocytes to the vessel wall as assessed by intravital microscopy. This effect was not present in P2Y 6 -deficient mice. Atherosclerotic aortas of low-density lipoprotein receptor-deficient mice consuming high-cholesterol diet for 16 weeks expressed significantly more transcripts and protein of P2Y 6 than respective controls. Finally, P2Y 6 −/− /low-density lipoprotein receptor-deficient mice consuming high-cholesterol diet for 16 weeks developed significantly smaller atherosclerotic lesions compared with P2Y 6 +/+ /low-density lipoprotein receptor-deficient mice. Bone marrow transplantation identified a crucial role of P2Y 6 on vascular resident cells, most likely endothelial cells, on leukocyte recruitment and atherogenesis. Atherosclerotic lesions of P2Y 6 -deficient mice contained fewer macrophages and fewer lipids as determined by immunohistochemistry. Mechanistically, RNA expression of vascular cell adhesion molecule 1 and interleukin-6 was decreased in these lesions and P2Y 6 -deficient macrophages took up less modified low-density lipoprotein cholesterol. 16 demonstrated that P2Y 6 promotes host defense by augmenting the expression of monocyte chemoattractant protein 1 (MCP-1) and guiding monocytes to the location of infection. Besides the chemokine-driven recruitment, also a direct chemoattractant activity of the UDP-P2Y 6 R axis has been described 17 for leukocytes. Thus, stimulation of the P2Y 6 R has been implicated with chronic inflammatory diseases. Indeed, selective inhibition or knockdown of P2Y 6 R reduced all cardinal features of experimental acute and chronic allergic asthma in mice. 18 Furthermore, P2Y 6 contributes to inflammation of intestinal mucosa promoting IL-8-dependent neutrophil recruitment. Conclusions-We 19Pyridoxal phosphate-6-azophenyl-2′,4′-disulfonic acid, a synthetic substance blocking several purinergic receptors including P2Y 6 , P2Y 4 , P2Y 11 , and purinergic receptors X (ion channels), reduced atherosclerosis in...

Extracellular ATP Induces Vascular Inflammation and Atherosclerosis via Purinergic Receptor Y 2 in Mice

“…42 Deficiency of P2Y 1 , P2Y 6 , or P2Y 12 receptors limited experimental atherosclerosis. 17,19,22 We demonstrate that P2Y 2 -deficient LDLR −/− mice develop significantly smaller plaques than P2Y 2 -competent control LDLR −/− mice. In line with the results of the intravital Before and after 16 weeks of high cholesterol diet blood was taken and total leukocytes and platelets were measured in thousand per microliter (tsd/μL).…”

“…18 Recently, we could show that extracellular UDP induced leukocyte rolling and adhesion via endothelial P2Y 6 . 19 Intraperitoneal injection of ATP enhanced total neutrophil and macrophage count in peritoneal lavage by inducing macrophage inflammatory protein 2 via P2X 7 and P2Y 2 .…”

Purinergic Receptors in Thrombosis and Inflammation

“…On the one hand, in one study, it was reported that whole body P2Y 6 deficiency reduced atherosclerosis in mice. 70 These authors identified a crucial role of the P2Y 6 receptor expressed on vascular cells, most likely on ECs, without any contribution from the P2Y 6 present on hematopoietic-derived cells. On the other hand, in another recent study, it was reported that whole body P2Y 6 deficiency failed to impact lesion formation, whereas P2Y 6 deficiency on hematopoietic cells reduced lesion development.…”

Loss of Mouse P2Y6 Nucleotide Receptor Is Associated with Physiological Macrocardia and Amplified Pathological Cardiac Hypertrophy

“…Nishida et al (7) showed that inhibition of P2Y 6 receptor using the specific antagonist MRS2578 decreased collagen deposition after transverse aortic constriction, without affecting cardiac hypertrophy induced in this model. Also, P2Y 6 receptor seems to have a deleterious role in atherosclerosis, being enriched in the sclerotic lesions and favoring inflammation (8,9). These various effects of nucleotides are depending on cell-specific expression of P2Y subtypes involved: mouse P2Y 4 receptor is not expressed in cardiomyocytes and is mainly expressed in cardiac endothelial cells, whereas mouse P2Y 2 and P2Y 6 receptors were found in all tested cardiac cells (2,3,6,7).…”