title: Sphingosine-1-phosphate receptor 3 promotes recruitment of monocyte/macrophages in inflammation and atherosclerosis.
abstract: BACKGROUND
  The role of sphingosine-1-phosphate (S1P) and its receptors in the pathogenesis of atherosclerosis has not been investigated.
  
  
  OBJECTIVE
  We hypothesized that the S1P receptor 3 (S1P(3)) plays a causal role in the pathogenesis of atherosclerosis.
  
  
  RESULTS
  We examined atherosclerotic lesion development in mice deficient for S1P(3) and apolipoprotein (Apo)E. Although S1P(3) deficiency did not affect lesion size after 25 or 45 weeks of normal chow diet, it resulted in a dramatic reduction of the monocyte/macrophage content in lesions of S1P(3)(-/-)/ApoE(-/-) double knockout mice. To search for putative defects in monocyte/macrophage recruitment, we examined macrophage-driven inflammation during thioglycollate-induced peritonitis. Elicited peritoneal macrophages were reduced in S1P(3)-deficient mice and expressed lower levels of tumor necrosis factor-α and monocyte chemoattractant protein-1. Bone marrow-derived S1P(3)-deficient macrophages produced less MCP-1 in response to lipopolysaccharide stimulation. In vitro, S1P was chemotactic for wild-type but not S1P(3)-deficient peritoneal macrophages. In vivo, S1P concentration increased rapidly in the peritoneal cavity after initiation of peritonitis. Treatment with the S1P analog FTY720 attenuated macrophage recruitment to the peritoneum. Studies in bone marrow chimeras showed that S1P(3) in both hematopoietic and nonhematopoietic cells contributed to monocyte/macrophage accumulation in atherosclerotic lesions. Finally, S1P(3) deficiency increased the smooth muscle cell content of atherosclerotic lesions and enhanced neointima formation after carotid ligation arguing for an antiproliferative/antimigratory role of S1P(3) in the arterial injury response.
  
  
  CONCLUSIONS
  Our data suggest that S1P(3) mediates the chemotactic effect of S1P in macrophages in vitro and in vivo and plays a causal role in atherosclerosis by promoting inflammatory monocyte/macrophage recruitment and altering smooth muscle cell behavior.
authors.affiliation: Institute for Pathophysiology, University Hospital Essen, Hufelandstrasse 55, 45122 Essen, Germany.
authors.forename: Petra
authors.initials: P
authors.lastname: Keul
authors.forename: Susann
authors.initials: S
authors.lastname: Lucke
authors.forename: Karin
authors.initials: K
authors.lastname: von Wnuck Lipinski
authors.forename: Constantin
authors.initials: C
authors.lastname: Bode
authors.forename: Markus
authors.initials: M
authors.lastname: Gräler
authors.forename: Gerd
authors.initials: G
authors.lastname: Heusch
authors.forename: Bodo
authors.initials: B
authors.lastname: Levkau
mesh_terms: D000818:Animals; D001057:Apolipoproteins E / Q000235:genetics / Q000378:metabolism; D050197:Atherosclerosis / Q000378:metabolism* / Q000473:pathology*; D002465:Cell Movement / Q000502:physiology; D049109:Cell Proliferation; D004195:Disease Models, Animal; D000068876:Fingolimod Hydrochloride; D007249:Inflammation / Q000378:metabolism* / Q000473:pathology*; D008264:Macrophages / Q000187:drug effects / Q000473:pathology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009000:Monocytes / Q000187:drug effects / Q000473:pathology*; D010538:Peritonitis / Q000139:chemically induced / Q000378:metabolism / Q000473:pathology; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000378:metabolism; D011409:Propylene Glycols / Q000494:pharmacology; D049349:Receptors, Lysosphingolipid / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D013110:Sphingosine / Q000031:analogs & derivatives / Q000494:pharmacology; D000081025:Sphingosine-1-Phosphate Receptors; D013864:Thioglycolates / Q000009:adverse effects; D000099157:Sphingosine Kinase
chemical_list: D001057:Apolipoproteins E; D000068876:Fingolimod Hydrochloride; D017853:Phosphotransferases (Alcohol Group Acceptor); D011409:Propylene Glycols; D049349:Receptors, Lysosphingolipid; D013110:Sphingosine; D000081025:Sphingosine-1-Phosphate Receptors; D013864:Thioglycolates; D000099157:Sphingosine Kinase; C501285:S1pr3 protein, mouse