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Cell Biology/Signaling |
From the Charite - Campus Benjamin Franklin, Medizinische Klinik IV (M.T., M.S., U.J.T., M.v.d.G.), Berlin, Germany; Leibnitz-Institut für Arterioskleroseforschung an der Universität Münster (A.P., A.K., S.L., J.-R.N.), Münster, Germany; the Center for Liver, Digestive, and Metabolic Diseases (U.J.T.), University Medical Center Groningen, the Netherlands; Institut für Pathophysiologie im Zentrum für Innere Medizin (P.K., B.L.), Universität Essen, Germany; Assmann-Stiftung für Prävention (G.A.), Münster, Germany; the Department of Molecular Biology (J.C.), Scripps Research Institute, La Jolla, Calif; and Centrum für Laboratoriumsmedizin (J.-R.N.), Universitätsklinikum Münster, Münster, Germany.
Correspondence to Markus van der Giet, MD, Medizinische Klinik – SP Nephrologie, Charite – Campus Benjamin Franklin, Hindenburgdamm 30, 12203 Berlin, Germany. E-mail markus.vandergiet{at}charite.de
Abstract
Objectives— High-density lipoprotein (HDL) levels are inversely proportional to the risk of atherosclerosis, but mechanisms of HDL atheroprotection remain unclear. Monocyte chemoatractant protein-1 (MCP-1) constitutes an early component of inflammatory response in atherosclerosis. Here we investigated the influence of HDL on MCP-1 production in vascular smooth muscle cells (VSMCs) and rat aortic explants.
Methods and Results— HDL inhibited the thrombin-induced production of MCP-1 in a concentration-dependent manner. The HDL-dependent inhibition of MCP-1 production was accompanied by the suppression of reactive oxygen species (ROS), which regulate the MCP-1 production in VSMCs. HDL inhibited NAD(P)H oxidase, the preponderant source of ROS in the vasculature, and prevented the activation of Rac1, which precedes NAD(P)H-oxidase activation. The HDL capacity to inhibit MCP-1 production, ROS generation, and NAD(P)H-oxidase activation was emulated by sphingosine 1-phosphate (S1P) and sphingosylphosphorylcholine (SPC), two lysosphingolipids present in HDL, but not by apolipoprotein A-I. HDL-, S1P-, and SPC-induced inhibition of MCP-1 production was attenuated in VSMCs pretreated with VPC23019, an antagonist of lysosphingolipid receptors S1P1 and S1P3, but not by JTE013, an antagonist of S1P2. In addition, HDL, S1P, and SPC failed to inhibit MCP1 production and ROS generation in aortas from S1P3- and SR-B1-deficient mice.
Conclusion— HDL-associated lysosphingolipids inhibit NAD(P)H oxidase-dependent ROS generation and MCP-1 production in a process that requires coordinate signaling through S1P3 and SR-B1 receptors.
HDL inhibits thrombin-induced production of monocyte chemoattractant protein-1 (MCP-1) in vascular smooth muscle cells and aortas. The reduced MCP-1 production is associated with inhibition of reactive oxygen species, NAD(P)H oxidase, and Rac-1, is not observed in aortas from S1P3–/– and SR-B1–/– mice, and is emulated by HDL-associated sphingosine-1-phosphate and sphingosylphosphoryl-choline.
Key Words: HDL sphingosine-1-phosphate MCP-1 ROS NADPH-oxidase
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