title: Dose-dependent modulation of tissue factor protein and procoagulant activity in human monocyte-derived macrophages by oxidized low density lipoprotein.
abstract: OBJECTIVE
  Oxidized low-density lipoprotein (oxLDL) interacts with macrophages and is implicated in atherogenesis. Macrophages are also the major source within the atherosclerotic plaque of tissue factor (TF), the membrane-bound glycoprotein receptor that triggers the coagulation cascade in vivo and contributes to plaque thrombogenicity. In this study we tested the hypothesis that oxLDL modulates TF expression in human monocyte-derived macrophages (MDMs).
  
  
  METHODS
  Mononuclear cells were isolated from human blood, allowed to differentiate into MDMs during 8 days in cell culture, and then exposed to varying concentrations of oxLDL in the presence or absence of lipopolysaccharide (LPS). TF procoagulant activity (TF-PCA) of MDMs was measured by one-stage recalcification clotting assay using human recombinant TF as standard. TF protein was evaluated by Western blotting, and TF mRNA was determined by Northern blot analysis.
  
  
  RESULTS
  OxLDL at 5-10 µg/mL increased TF-PCA, TF protein, and mRNA in MDMs, whereas 20-100 µg/mL oxLDL inhibited TF-PCA, protein expression, and mRNA expression in these cells even in the face of LPS stimulation.
  
  
  CONCLUSIONS
  Low concentrations of oxLDL enhance TF expression in MDMs, whereas higher concentrations attenuate TF expression both at baseline as well as following LPS stimulation. Both TF-PCA and TF protein follow this dose-response pattern that is preceded by concordant mRNA changes. Thus, we have demonstrated modulation by oxLDL of TF protein and bioactivity in MDMs.
authors.affiliation: Atherosclerosis Research Center, Division of Cardiology, Department of Medicine, The CSMC Burns & Allen Research Institute. meisel@hy.health.gov.il
authors.forename: Simcha Ron
authors.initials: SR
authors.lastname: Meisel
authors.forename: Xiao-Ping
authors.initials: XP
authors.lastname: Xu
authors.forename: Thomas Scott
authors.initials: TS
authors.lastname: Edgington
authors.forename: Bojan
authors.initials: B
authors.lastname: Cercek
authors.forename: John
authors.initials: J
authors.lastname: Ong
authors.forename: Sanjay
authors.initials: S
authors.lastname: Kaul
authors.forename: Prediman Krishan
authors.initials: PK
authors.lastname: Shah
mesh_terms: D050197:Atherosclerosis / Q000378:metabolism; D015152:Blotting, Northern; D015153:Blotting, Western; D002454:Cell Differentiation; D003029:Coagulants / Q000378:metabolism; D005434:Flow Cytometry / Q000379:methods; D006801:Humans; D008070:Lipopolysaccharides / Q000378:metabolism; D008077:Lipoproteins, LDL / Q000378:metabolism*; D008264:Macrophages / Q000166:cytology* / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D011994:Recombinant Proteins / Q000627:therapeutic use; D013925:Thromboplastin / Q000378:metabolism
chemical_list: D003029:Coagulants; D008070:Lipopolysaccharides; D008077:Lipoproteins, LDL; D012333:RNA, Messenger; D011994:Recombinant Proteins; C099252:oxidized low density lipoprotein; D013925:Thromboplastin