title: The pro-atherogenic effects of macrophages are reduced upon formation of a complex between C-reactive protein and lysophosphatidylcholine.
abstract: BACKGROUND
  C-reactive protein (CRP) and lysophosphatidylcholine (LPC) are phosphorylcholine-(PC)-containing oxidized phospholipids (oxPLs) found in oxidized LDL (oxLDL), which trigger pro-atherogenic activities of macrophages during the process of atherosclerosis. It has been previously reported that CRP binds to the PC head group of oxLDL in a calcium-dependent manner. The aim of this study was to investigate the importance of binding between CRP and LPC to the pro-atherogenic activities of macrophages.
  A chemiluminescent immunoassay and HPLC showed that human recombinant CRP formed a stable complex with LPC in the presence of calcium. The Kd value of the binding of the CRP-LPC complex to the receptors FcγRIA or FcγRIIA was 3-5 fold lower than that of CRP alone. The CRP-LPC complex triggered less potent generation of reactive oxygen species and less activation of the transcription factors AP-1 and NF-kB by human monocyte-derived macrophages in comparison to CRP or LPC alone. However, CRP did not affect activities driven by components of oxLDL lacking PC, such as upregulation of PPRE, ABCA1, CD36 and PPARγ and the enhancement of cholesterol efflux by human macrophages. The presence of CRP inhibited the association of Dil-labelled oxLDL to human macrophages.
  
  
  CONCLUSIONS
  The formation of complexes between CRP and PC-containing oxPLs, such as LPC, suppresses the pro-atherogenic effects of CRP and LPC on macrophages. This effect may in part retard the progression of atherosclerosis.
authors.affiliation: Department of Medicine, University of California San Diego, La Jolla, CA, USA.|Present address: Bayer Korea, 7th fl. Samsung-Boramae Omni Tower, 395-62, Sindaebang dong Dongzak-gu, Seoul, South Korea.
authors.forename: Mi-Kyung
authors.initials: MK
authors.lastname: Chang
authors.affiliation: Department of Medicine, University of California San Diego, La Jolla, CA, USA.
authors.forename: Karsten
authors.initials: K
authors.lastname: Hartvigsen
authors.affiliation: University of Ulsan College of Medicine, Asan Medical Center, 388-1 Pungnap-2 dong Songpa-gu 138-736, Seoul, South Korea.
authors.forename: Jewon
authors.initials: J
authors.lastname: Ryu
authors.affiliation: University of Ulsan College of Medicine, Asan Medical Center, 388-1 Pungnap-2 dong Songpa-gu 138-736, Seoul, South Korea.
authors.forename: Yuna
authors.initials: Y
authors.lastname: Kim
authors.affiliation: University of Ulsan College of Medicine, Asan Medical Center, 388-1 Pungnap-2 dong Songpa-gu 138-736, Seoul, South Korea.
authors.forename: Ki Hoon
authors.initials: KH
authors.lastname: Han