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 November 1, 2010; First published October 18, 2010
Citation Information: J Clin Invest. 2010;120(11):3979-3995. https://doi.org/10.1172/JCI42315.
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Categories: 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 4

S1PR2 deficiency inhibits uptake of modified LDL and stimulates cholesterol efflux in BM-derived macrophages.

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S1PR2 deficiency inhibits uptake of modified LDL and stimulates choleste...
(A) Foam cell formation assay. Macrophages from S1pr2+/+Apoe–/– (left panels) and S1pr2–/–Apoe–/– (right panels) mice were exposed to oxLDL for 6 hours. Cells containing oil red O–positive fat droplets were considered foam cells. Scale bars: 20 μm. (B) Quantified data of oil red O–positive cells. *P < 0.05. (C) Uptake of Dil-labeled acetylated–LDL (ac-LDL). Macrophages from S1pr2+/+Apoe–/– (left panel) and S1pr2–/–Apoe–/– (right panel) mice were incubated with Dil-labeled ac-LDL for 4 hours. Scale bars: 20 μm. (D) Quantified data of Dil-labeled ac-LDL uptake is shown. (n = 3 each). *P < 0.05. (E) Cholesterol efflux from cholesterol-loaded macrophages. Macrophages from S1pr2+/+Apoe–/– (white bars) and S1pr2–/–Apoe–/– (black bars) mice were loaded with [3H]-labeled cholesterol. Cholesterol-loaded macrophages were incubated in the media containing either 0.2% BSA, 2% serum (FBS), or 50 μg/ml HDL as acceptor for 6 hours. The media and cells were collected for counting [3H] radioactivity (n = 3 each). *P < 0.05. Data are expressed as mean ± SEM.