Regulation of bradykinin receptor gene expression in human lung fibroblasts

In WI-38 human fibroblasts, interleukin-1 beta and tumour necrosis factor-alpha (TNF-alpha) increased bradykinin B(1) receptor mRNA, which peaked between 2 and 4 h, remaining elevated for 20 h. Binding of the bradykinin B(1) receptor selective ligand [3H]des-Arg(10)-kallidin, also increased, peaking at 4 h and remaining elevated for 20 h. The B(max) value for [3H]des-Arg(10)-kallidin rose from 280+/-102 fmol/mg (n=3) to 701+/-147 fmol/mg (n=3), but the K(D) value remained unaltered (control, 1.04+/-0.33 nM (n=3); interleukin-1 beta, 0.88+/-0.41 nM (n=3)). The interleukin-1 beta-induced [3H]des-Arg(10)-kallidin binding sites were functional receptors, as bradykinin B(1) receptor agonist-induced responses increased in treated cells. Bradykinin B(2) receptor mRNA and [3H]bradykinin binding were upregulated by interleukin-1 beta, but not TNF-alpha. The effect of interleukin-1 beta on bradykinin B(2) receptors was smaller than for bradykinin B(1) receptors. Cycloheximide prevented interleukin-1 beta-mediated increases in B(1) and B(2) binding, but not mRNA suggesting that de novo synthesis of a transcriptional activator was unnecessary.