title: Activation of CXCR7 limits atherosclerosis and improves hyperlipidemia by increasing cholesterol uptake in adipose tissue.
abstract: BACKGROUND
  The aim of this study was to determine the role of the chemokine receptor CXCR7 in atherosclerosis and vascular remodeling. CXCR7 is the alternative receptor of CXCL12, which regulates stem cell-mediated vascular repair and limits atherosclerosis via its receptor, CXCR4.
  
  
  RESULTS
  Wire-induced injury of the carotid artery was performed in mice with a ubiquitous, conditional deletion of CXCR7 and in mice treated with the synthetic CXCR7 ligand CCX771. The effect of CCX771 treatment on atherosclerosis was studied in apolipoprotein E-deficient (Apoe(-/-)) mice fed a high-fat diet for 12 weeks. Lipoprotein fractions were quantified in the plasma of Apoe(-/-) mice by fast protein liquid chromatography. Uptake of DiI-labeled very low-density lipoprotein to adipose tissue was determined by 2-photon microscopy. We show that genetic deficiency of Cxcr7 increased neointima formation and lesional macrophage accumulation in hyperlipidemic mice after vascular injury. This was related to increased serum cholesterol levels and subsequent hyperlipidemia-induced monocytosis. Conversely, administration of the CXCR7 ligand CCX771 to Apoe(-/-) mice inhibited lesion formation and ameliorated hyperlipidemia after vascular injury and during atherosclerosis. Treatment with CCX771 reduced circulating very low-density lipoprotein levels but not low-density lipoprotein or high-density lipoprotein levels and increased uptake of very low-density lipoprotein into Cxcr7-expressing white adipose tissue. This effect of CCX771 was associated with an enhanced lipase activity and reduced expression of Angptl4 in adipose tissue.
  
  
  CONCLUSIONS
  CXCR7 regulates blood cholesterol by promoting its uptake in adipose tissue. This unexpected cholesterol-lowering effect of CXCR7 is beneficial for atherosclerotic vascular diseases, presumably via amelioration of hyperlipidemia-induced monocytosis, and can be augmented with a synthetic CXCR7 ligand.
authors.affiliation: Institute for Molecular Cardiovascular Research (X.L., R.R.K., A.T., K.H., S.A., Z.W., M.v.Z., C.W., A.S.), Core Facility Two-Photon Imaging, Interdisciplinary Center for Clinical Research Aachen (S.K.), and Experimental Molecular Imaging (F.G., F.K.), RWTH Aachen University, Aachen, Germany; Institute for Cardiovascular Prevention, Ludwig Maximilians University Munich, Munich, Germany (M.Z., R.R.K., K.H., C.W., A.S.); ChemoCentryx Inc, Mountain View, CA (M.E.P., T.J.S.); Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands (M.v.Z., C.W.); and Munich Heart Alliance, Munich, Germany (C.W., A.S.).
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Li
authors.forename: Mengyu
authors.initials: M
authors.lastname: Zhu
authors.forename: Mark E
authors.initials: ME
authors.lastname: Penfold
authors.forename: Rory R
authors.initials: RR
authors.lastname: Koenen
authors.forename: Anna
authors.initials: A
authors.lastname: Thiemann
authors.forename: Kathrin
authors.initials: K
authors.lastname: Heyll
authors.forename: Shamima
authors.initials: S
authors.lastname: Akhtar
authors.forename: Seena
authors.initials: S
authors.lastname: Koyadan
authors.forename: Zhuojun
authors.initials: Z
authors.lastname: Wu
authors.forename: Felix
authors.initials: F
authors.lastname: Gremse
authors.forename: Fabian
authors.initials: F
authors.lastname: Kiessling
authors.forename: Marc
authors.initials: M
authors.lastname: van Zandvoort
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Schall
authors.forename: Christian
authors.initials: C
authors.lastname: Weber
authors.forename: Andreas
authors.initials: A
authors.lastname: Schober
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism*; D000818:Animals; D050197:Atherosclerosis / Q000378:metabolism* / Q000517:prevention & control; D002784:Cholesterol / Q000378:metabolism*; D006949:Hyperlipidemias / Q000378:metabolism* / Q000517:prevention & control; D008024:Ligands; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D054387:Receptors, CXCR / Q000819:agonists / Q000096:biosynthesis*
chemical_list: C501897:Cmkor1 protein, mouse; D008024:Ligands; D054387:Receptors, CXCR; D002784:Cholesterol
keywords: atherosclerosis; coronary restenosis; hypercholesterolemia