Post-Transcriptional Regulation of Bradykinin B1 and B2 Receptor Gene Expression in Human Lung Fibroblasts by Tumor Necrosis Factor-α: Modulation by Dexamethasone

  1. El-Bdaoui Haddad1,
  2. Alison J. Fox1,
  3. Jonathan Rousell1,
  4. Gillian Burgess2,
  5. Peter McIntyre2,
  6. Peter J. Barnes1 and
  7. K. Fan Chung1
  1. 1Department of Thoracic Medicine (E.-B.H., A.J.F., J.R., P.J.B., K.F.C.), National Heart and Lung Institute, Imperial College School of Medicine, London, United Kingdom; and 2Novartis Institute for Medical Sciences (G.B., P.M.), London, United Kingdom

    Abstract

    The cellular and molecular mechanisms governing bradykinin B1 and B2 receptor expression and function are poorly understood. We investigated the regulation of both B1 and B2 receptors in human embryonic lung fibroblasts (HEL 299) by the proinflammatory cytokines tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β). TNF-α and IL-1β both induced a rapid and transient increase in B1 and B2 receptor mRNA expression that was maximal by 2 h, accompanied by an increase in B1 and B2 receptor protein, as measured by radioligand binding assay with [3H]des-Arg10-kallidin, and [3H]bradykinin, respectively. The induced B1 receptors were functionally coupled, because the B1 agonist, des-Arg10-kallidin, induced an increase in arachidonic acid release in TNF-α-stimulated cells but not in control cells. The induction of B1 and the up-regulation of B2 receptors by TNF-α was partly mediated through activation of p38 mitogen-activated protein kinase and that of B2 receptor by protein kinase A. TNF-α and IL-1β regulation of both B1 and B2 receptors was inhibited by dexamethasone. When compared with vehicle-treated cells, dexamethasone increased the rate of decline of both B1 and B2 receptor mRNAs. Nuclear run-on experiments demonstrate that the induction of B1 and the up-regulation of B2 receptors as well as the inhibitory effect of dexamethasone are entirely mediated through post-transcriptional mechanisms.

    Footnotes

    • Send reprint requests to: Dr. El-Bdaoui Haddad, Department of Pharmacology, Aventis Pharmaceuticals, Rainham Road South Dagenham, Essex RM10 7XS, United Kingdom. E-mail: el-bdaoui.haddad{at}aventis.com

    • This work was supported by a Wellcome Trust Career Development Award (to A.J.F.) and by a fellowship from the European Union (to E.-B.H.).

    • Abbreviations:
      BK
      bradykinin
      KD
      kallidin
      TNF-α
      tumor necrosis factor α
      IL-1β
      interleukin 1β
      MAPK
      mitogen-activated protein kinase
      ERK
      extracellular signal-regulated kinase
      JNK
      c-Jun NH2-terminal protein kinase
      PKA
      cAMP-dependent protein kinase
      PKC
      protein kinase C
      SSC
      sodium chloride/sodium citrate buffer
      GAPDH
      glyceraldehyde-3-phosphate dehydrogenase
      PAGE
      polyacrylamide gel electrophoresis
      TES
      2-{[2-hydroxy-1,1-bis(hydroxymethyl)ethyl]amino}ethanesulfonic acid
      HBSS
      Hanks' balanced salt solution
      [3H]AA
      [3H]arachidonic acid
      • Received October 12, 1999.
      • Accepted February 8, 2000.
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    1. Molecular Pharmacology June 1, 2000 vol. 57 no. 6 1123-1131
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