Depletion of FOXP3+ regulatory T cells promotes hypercholesterolemia and atherosclerosis
Roland Klingenberg, … , Tim Sparwasser, Göran K. Hansson
Roland Klingenberg, … , Tim Sparwasser, Göran K. Hansson
Published February 15, 2013
Citation Information: J Clin Invest. 2013;123(3):1323-1334. https://doi.org/10.1172/JCI63891.
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Research Article Cardiology

Depletion of FOXP3+ regulatory T cells promotes hypercholesterolemia and atherosclerosis

Abstract

Atherosclerosis is a chronic inflammatory disease promoted by hyperlipidemia. Several studies support FOXP3-positive regulatory T cells (Tregs) as inhibitors of atherosclerosis; however, the mechanism underlying this protection remains elusive. To define the role of FOXP3-expressing Tregs in atherosclerosis, we used the DEREG mouse, which expresses the diphtheria toxin (DT) receptor under control of the Treg-specific Foxp3 promoter, allowing for specific ablation of FOXP3+ Tregs. Lethally irradiated, atherosclerosis-prone, low-density lipoprotein receptor–deficient (Ldlr–/–) mice received DEREG bone marrow and were injected with DT to eliminate FOXP3+ Tregs. Depletion of Tregs caused a 2.1-fold increase in atherosclerosis without a concomitant increase in vascular inflammation. These mice also exhibited a 1.7-fold increase in plasma cholesterol and an atherogenic lipoprotein profile with increased levels of VLDL. Clearance of VLDL and chylomicron remnants was hampered, leading to accumulation of cholesterol-rich particles in the circulation. Functional and protein analyses complemented by gene expression array identified reduced protein expression of sortilin-1 in liver and increased plasma enzyme activity of lipoprotein lipase, hepatic lipase, and phospholipid transfer protein as mediators of the altered lipid phenotype. These results demonstrate that FOXP3+ Tregs inhibit atherosclerosis by modulating lipoprotein metabolism.

Authors

Roland Klingenberg, Norbert Gerdes, Robert M. Badeau, Anton Gisterå, Daniela Strodthoff, Daniel F.J. Ketelhuth, Anna M. Lundberg, Mats Rudling, Stefan K. Nilsson, Gunilla Olivecrona, Stefan Zoller, Christine Lohmann, Thomas F. Lüscher, Matti Jauhiainen, Tim Sparwasser, Göran K. Hansson

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Figure 5

VLDL/CMR lipoprotein catabolism is impaired in Treg-depleted mice.

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VLDL/CMR lipoprotein catabolism is impaired in Treg-depleted mice. (A) B...
(A) Biosynthesis of apoB-containing plasma lipoproteins. Data show plasma cholesterol levels in chimeric DEREG/Ldlr–/– mice treated for 8 weeks with DT or PBS followed by i.v. administration of Triton WR-1339 to inhibit lipoprotein lipase–dependent VLDL catabolism; n = 9 (PBS) and n = 7 (DT), respectively. (B) Clearance of injected FITC-VLDL in chimeric DEREG/Ldlr–/– mice treated for 8 weeks with DT or PBS. FITC-derived fluorescence was analyzed in plasma samples at the indicated time points. Data for each individual were normalized to the fluorescence of plasma taken 1 minute after injection; n = 4 per group. (C) In vivo turnover of CM particles injected into chimeric DEREG/Ldlr–/– mice treated for 8 weeks with DT or PBS. Data show kinetics of the CM [14C] retinol core particle clearance from blood and are expressed as radiolabeled moieties corrected for weight; n = 5 (PBS); n = 7 (DT). (D) CM [14C] retinol uptake in the liver. Data expressed as radiolabeled moieties corrected for weight; n = 5 (PBS); n = 7 (DT). *P < 0.05.