title: A proteomic analysis of C-reactive protein stimulated THP-1 monocytes.
abstract: BACKGROUND
  C-reactive protein (CRP) is a predictor of cardiovascular risk. It circulates as a pentameric protein in plasma. Recently, a potential dissociation mechanism from the disc-shaped pentameric CRP (pCRP) into single monomers (monomeric or mCRP) has been described. It has been shown that mCRP has strong pro-inflammatory effects on monocytes. To further define the role of mCRP in determining monocyte phenotype, the effects of CRP isoforms on THP-1 protein expression profiles were determined. The hypothesis to be tested was that mCRP induces specific changes in the protein expression profile of THP-1 cells that differ from that of pCRP.
  
  
  METHODS
  Protein cell lysates from control and mCRP, pCRP or LPS-treated THP-1 cells were displayed using 2-dimensional SDS PAGE and compared. Differentially expressed proteins were identified by MALDI-TOF MS and confirmed by Western blotting.
  
  
  RESULTS
  mCRP significantly up-regulates ubiquitin-activating enzyme E1, a member of the ubiquitin-proteasome system in THP-1 monocytes. Furthermore, HSP 70, alpha-actinin-4 (ACTN4) and alpha-enolase/enolase 1 were upregulated. The proteomic profile of LPS and pCRP treated monocytes differ significantly from that of mCRP.
  
  
  CONCLUSIONS
  The data obtained in this study support the hypothesis that isoform-specific effects of CRP may differentially regulate the phenotype of monocytes.
authors.affiliation: Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia. steffen.eisenhardt@uniklinik-freiburg.de.
authors.forename: Steffen U
authors.initials: SU
authors.lastname: Eisenhardt
authors.forename: Jonathon
authors.initials: J
authors.lastname: Habersberger
authors.forename: Karen
authors.initials: K
authors.lastname: Oliva
authors.forename: Graeme I
authors.initials: GI
authors.lastname: Lancaster
authors.forename: Mustafa
authors.initials: M
authors.lastname: Ayhan
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Woollard
authors.forename: Holger
authors.initials: H
authors.lastname: Bannasch
authors.forename: Greg E
authors.initials: GE
authors.lastname: Rice
authors.forename: Karlheinz
authors.initials: K
authors.lastname: Peter