title: [The effects of atorvastatin on C-reactive protein induced Toll-like receptor 4 expression on CD14+ monocyte].
abstract: OBJECTIVE
  To investigate the effects of atorvastatin on C-reactive protein (CRP) induced Toll-Like receptor 4 (TLR4)expression on CD14+ monocyte, and the production of proinflammatory cytokines tumor necrosis factor alpha (TNFalpha), interleukin-6 (IL-6), matrix metalloproteinases-9 (MMP-9), and to study the anti-inflammatory mechanisms of statins.
  
  
  METHODS
  The monocytes were isolated from blood of healthy volunteers by the Ficoll density gradient and stimulated by CRP with different doses (5, 25, 50, 100 microg/ml) and different exposure time (6, 12, 24, 48 h). Cells were also incubated with atorvastatin of different doses (1.0, 2.5, 5.0, 7.5, 10.0 micromol/L) in the presence of CRP 50 microg/ml. The protein expression of TLR4 was measured by flow cytometry, mRNA expression of TLR4 and of myeloid differentiation protein (MD2)was detected by quantitative PCR. TNFalpha, IL-6, MMP-9 concentrations in supernatants of cultured medium were measured by ELISA.
  
  
  RESULTS
  (1) Compared with the un-stimulated control group, enhanced TLR4 protein expression was already detected at a concentration of 5 microg/ml of CRP and increased in a dose-dependent manner (32.22 +/- 2.80)%, (49.94 +/- 5.58)%, (74.82 +/- 3.24)% and (90.82 +/-2.88)% at 5, 25, 50 and 100 microg/ml CRP. (2) TLR4 protein expression on 50 microg/ml CRP stimulated cells also increased in a time-dependent manner (29.80 +/- 2.70)%, (47.44 +/- 4.41)%, (81.71 +/- 2.92)% and (50.57 +/- 3.34)% after 6 h, 12 h, 24 h, 48 h. (3) When monocytes were incubated with CRP 50 microg/ml and atorvastatin (1.0, 2.5, 5.0, 7.5, 10.0 micromol/L), protein expression [(68.17 +/- 1.71)%, (52.43 +/- 1.38)%, (27.72 +/- 4.55)%, (17.46 +/- 3.20)%, (9.99 +/- 2.81)%] and mRNA expression (82.72%, 67.34%, 48.16%, 30.88%, 13.85%) of TLR4 as well as mRNA expression of MD2 (81.78%, 71.04%, 47.85%, 27.06%, 18.30%) were reduced in a dose-dependent manner. (4) Level of TNFalpha, IL-6 and MMP-9 in supernatants was significantly reduced by atorvastatin (2.5 micromol/L) compared with control group (P < 0.01). When monocyte incubated with CRP 50 microg/ml and atorvastatin 10.0 micromol/L, the level of TNFalpha, IL-6, MMP-9 decreased to (25.8 +/- 2.5) microg/ml, (128.2 +/- 14.7) pg/ml, (65.2 +/- 12.3) ng/ml, respectively.
  
  
  CONCLUSIONS
  CRP increased the protein expression of TLR4 on CD14+ monocyte in a dose-dependent and time-dependent manner. Atorvastatin can inhibit the signal transduction of TLR4 and reduce proinflammatory cytokines release induced by CRP on CD14 monocyte, and this might be one of the anti-inflammatory mechanisms of atorvastatin.
authors.affiliation: Department of Cardiology, Third Affiliated Hospital, Sun Yat-sen University, Guangzhou 510630, China.
authors.forename: Long
authors.initials: L
authors.lastname: Peng
authors.forename: Yan-Ting
authors.initials: YT
authors.lastname: Luo
authors.forename: Jin-Lai
authors.initials: JL
authors.lastname: Liu
mesh_terms: D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D000069059:Atorvastatin; D002097:C-Reactive Protein / Q000378:metabolism*; D002478:Cells, Cultured; D006538:Heptanoic Acids / Q000494:pharmacology*; D006801:Humans; D018950:Lipopolysaccharide Receptors; D009000:Monocytes / Q000187:drug effects / Q000378:metabolism*; D011758:Pyrroles / Q000494:pharmacology*; D051197:Toll-Like Receptor 4 / Q000378:metabolism*
chemical_list: D000893:Anti-Inflammatory Agents; D006538:Heptanoic Acids; D018950:Lipopolysaccharide Receptors; D011758:Pyrroles; C495345:TLR4 protein, human; D051197:Toll-Like Receptor 4; D002097:C-Reactive Protein; D000069059:Atorvastatin