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 2

S1PR2 deficiency inhibits the expression of inflammatory cytokines and adhesion molecules and stimulates the expression of an antiinflammatory cytokine and phosphorylation of eNOS in the aorta of Apoe–/– mice.

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S1PR2 deficiency inhibits the expression of inflammatory cytokines and a...
(A) mRNA expression levels of TNF-α, IL-6, IL-10, IFN-γ, and MCP-1 (n = 5 each). (B) mRNA expression levels of VCAM-1 and ICAM-1 (n = 4 each). mRNA expression levels in the aortas from S1pr2+/+Apoe–/– and S1pr2–/–Apoe–/– mice fed HCD for 12 weeks were determined by real-time PCR in A and semiquantitative RT-PCR in B. 18S rRNA (for real-time PCR) and GAPDH (for RT-PCR) were used as internal controls. Data are expressed as the ratio of the values in S1pr2–/–Apoe–/– mice over S1pr2+/+Apoe–/– mice. *P < 0.05. (C) Representative immunostaining for VCAM-1 (upper panels) and ICAM-1 (lower panels) in the aortic sinus from S1pr2+/+Apoe–/– (left panels) and S1pr2–/–Apoe–/– (right panels) mice fed HCD for 12 weeks. Magnified views of the smaller boxed areas are shown in the insets (left upper of each panel). Scale bars: 100 μm. (D) Phosphorylation of eNOS in the aortas from S1pr2+/+Apoe–/– and S1pr2–/–Apoe–/– mice fed HCD for 12 weeks (n = 3 each). The extracts of the tissues were subjected to Western blotting, and quantified data are shown in the right panel. **P < 0.01. Data are expressed as mean ± SEM.