title: [Diclofenac inhibits Kv1.3 and Kir2.1 expressions in human macrophages and affects the membrane potential and foam cell formation].
abstract: OBJECTIVE
  To investigate the effect of diclofenac on the expression of Kv1.3 and Kir2.1 channels in human macrophages and the membrane potential and foaming process of the macrophages.
  
  
  METHODS
  The effect of diclofenac on the expression of Kv1.3 and Kir2.1 channels in cultured human monocyte-derived macrophages was investigated using real-time RT-PCR and Western blotting, and its effect on the membrane potential was analyzed with optical mapping of the membrane potential with voltage-sensitive dyes. The ratio of cholesterol ester (CE) in the macrophages following intake of oxidized low-density lipoprotein (OxLDL) was analyzed by an enzymatic fluorometric method.
  
  
  RESULTS
  The expression of Kv1.3 and Kir2.1 channels in the macrophages were down-regulated by diclofenac (1.5 µmol/L and 15 µmol/L). Compared with those in the control group, Kv1.3 mRNA expression was reduced by over 80% and 90% (P<0.05), and Kir2.1 mRNA by over 20% and 30% (P>0.05), respectively; both their protein expression was reduced by over 10% and 60% with a dose- dependent effect (P<0.05). Diclofenac at the two doses dose-dependently reduced the surface fluorescence intensity of the macrophage, and the membrane potential was decreased by 28% and 54%, respectively (P<0.05). Incubation of the macrophages with 30 mg/L OxLDL for 60 h caused an obvious enlargement of the cell volume and deposition of numerous lipid granules in cytoplasm, resulting also in a CE/TC ratio over 50% (P<0.05). Diclofenac at 1.5 and 15 µmol/L both significantly decreased the CE/TC ratio to (23.624∓3.34)% and (13.601∓2.916)% (P<0.05), respectively, but this effect did not show a dose-response relationship (P>0.05).
  
  
  CONCLUSIONS
  Diclofenac can significant down-regulate the expression of Kv1.3 and Kir2.1 channels in human macrophages, lower their membrane potential and inhibit the process of foam cell formation.
authors.affiliation: Department of Cardiology, First Affiliated Hospital of Xi'an Jiaotong University College of Medicine, Xi'an, China. xinjunlei@sohu.com
authors.forename: Xinjun
authors.initials: X
authors.lastname: Lei
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Xianfeng
authors.initials: X
authors.lastname: Lin
authors.forename: Dongqi
authors.initials: D
authors.lastname: Wang
authors.forename: Zuyi
authors.initials: Z
authors.lastname: Yuan
mesh_terms: D002478:Cells, Cultured; D004008:Diclofenac / Q000494:pharmacology*; D005487:Foam Cells / Q000166:cytology / Q000187:drug effects; D006801:Humans; D051664:Kv1.3 Potassium Channel / Q000378:metabolism*; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D008564:Membrane Potentials / Q000187:drug effects*; D024661:Potassium Channels, Inwardly Rectifying / Q000378:metabolism*
chemical_list: C489457:KCNJ2 protein, human; D051664:Kv1.3 Potassium Channel; D024661:Potassium Channels, Inwardly Rectifying; D004008:Diclofenac