Sphingosine-1-phosphate receptor-2 deficiency leads to inhibition of macrophage proinflammatory activities and atherosclerosis in apoE-deficient mice
Fei Wang, … , Makoto Kinoshita, Yoh Takuwa
Fei Wang, … , Makoto Kinoshita, Yoh Takuwa
Published October 18, 2010
Citation Information: J Clin Invest. 2010;120(11):3979-3995. https://doi.org/10.1172/JCI42315.
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Research Article Cardiology

Sphingosine-1-phosphate receptor-2 deficiency leads to inhibition of macrophage proinflammatory activities and atherosclerosis in apoE-deficient mice

Abstract

Sphingosine-1-phosphate (S1P) is a biologically active sphingolipid that has pleiotropic effects in a variety of cell types including ECs, SMCs, and macrophages, all of which are central to the development of atherosclerosis. It may therefore exert stimulatory and inhibitory effects on atherosclerosis. Here, we investigated the role of the S1P receptor S1PR2 in atherosclerosis by analyzing S1pr2–/– mice with an Apoe–/– background. S1PR2 was expressed in macrophages, ECs, and SMCs in atherosclerotic aortas. In S1pr2–/–Apoe–/– mice fed a high-cholesterol diet for 4 months, the area of the atherosclerotic plaque was markedly decreased, with reduced macrophage density, increased SMC density, increased eNOS phosphorylation, and downregulation of proinflammatory cytokines compared with S1pr2+/+Apoe–/– mice. Bone marrow chimera experiments indicated a major role for macrophage S1PR2 in atherogenesis. S1pr2–/–Apoe–/– macrophages showed diminished Rho/Rho kinase/NF-κB (ROCK/NF-κB) activity. Consequently, they also displayed reduced cytokine expression, reduced oxidized LDL uptake, and stimulated cholesterol efflux associated with decreased scavenger receptor expression and increased cholesterol efflux transporter expression. S1pr2–/–Apoe–/– ECs also showed reduced ROCK and NF-κB activities, with decreased MCP-1 expression and elevated eNOS phosphorylation. Pharmacologic S1PR2 blockade in S1pr2+/+Apoe–/– mice diminished the atherosclerotic plaque area in aortas and modified LDL accumulation in macrophages. We conclude therefore that S1PR2 plays a critical role in atherogenesis and may serve as a novel therapeutic target for atherosclerosis.

Authors

Fei Wang, Yasuo Okamoto, Isao Inoki, Kazuaki Yoshioka, Wa Du, Xun Qi, Noriko Takuwa, Koichi Gonda, Yasuhiko Yamamoto, Ryunosuke Ohkawa, Takumi Nishiuchi, Naotoshi Sugimoto, Yutaka Yatomi, Kunitoshi Mitsumori, Masahide Asano, Makoto Kinoshita, Yoh Takuwa

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Figure 9

S1PR2 mediates S1P-induced chemorepulsion and inhibition of proliferation in SMCs.

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S1PR2 mediates S1P-induced chemorepulsion and inhibition of proliferatio...
(A) Enhancement of SMC growth from aortic explants from S1pr2–/–Apoe–/– mice. Outgrowth of SMCs from aortic explants from S1pr2+/+Apoe–/– and S1pr2–/–Apoe–/– mice are shown (n = 3 each). The explants were individually placed in the culture dish and cultured for 4 days. (A) Phase contrast microscopic views (upper left) and quantified data of outgrowing cells are shown (upper right). Anti-BrdU immunostaining of proliferating cells. Outgrowing SMCs were labeled with BrdU and processed for anti-BrdU immunofluorescence staining. Fluorescent microscopic views (lower left) and quantified data of proliferating cells are shown (lower right). **P < 0.01. Scale bars: 100 μm (upper panels); 20 μm (lower panels). (B) Effects of S1P and PDGF on transwell migration of SMCs isolated from S1pr2+/+Apoe–/– and S1pr2–/–Apoe–/– mice. Various concentrations of S1P were added to the lower chamber in the presence and absence of PDGF-BB (10 ng/ml) in the lower chamber (n = 4 each). *P < 0.05, compared with the values in the absence of S1P. (C) Effects of S1P and PDGF on Rac activity. SMCs isolated from S1pr2+/+Apoe–/– (white bars) and S1pr2–/–Apoe–/– (black bars) mice were not treated or treated with either S1P (0.1 μM) alone for 5 minutes, PDGF-BB (10 ng/ml) alone for 3 minutes, or the combination of S1P and PDGF-BB. In the combination treatment, S1P was added 2 minutes before the addition of PDGF. Amounts of GTP-bound Rac were determined by the pulldown assay (n = 3 each). *P < 0.05; **P < 0.01 compared with nontreated SMCs. ##P < 0.01 compared with PDGF-BB–treated SMCs. Data are expressed as mean ± SEM.