Biochemical Journal

Research article

Interleukin 1 induces hypoxia-inducible factor 1 in human gingival and synovial fibroblasts

Ruth D. THORNTON, Pamela LANE, Ruth C. BORGHAEI, Elizabeth A. PEASE, Jaime CARO, Eugene MOCHAN


Rheumatoid arthritis and periodontitis are inflammatory diseases modulated by proinflammatory cytokines [e.g. interleukin (IL-1) 1 and tumour necrosis factor α], which activate local fibroblasts to do the following: (1) proliferate, (2) induce gene expression and (3) produce destructive metalloproteinases. Hypoxia-inducible factor 1 (HIF-1) is a heterodimeric transcription factor (composed of HIF-1α and HIF-1β/aryl hydrocarbon receptor nuclear transporter) that is modulated by hypoxia. HIF-1 binds to and induces several genes containing an HIF-1 consensus-binding site, including vascular endothelial growth factor and several glycolytic enzymes. Through differential screening of a human synovial fibroblast cDNA library, we identified HIF-1α as a clone up-regulated by IL-1. The mRNA for HIF-1α subunit was increased 3–4-fold by Northern blot analysis after cells had been incubated for 3h in the presence of IL-1. In addition, IL-1 increased the binding of the heterodimer HIF-1 to the HIF consensus sequence. These results suggest that HIF-1 might have a role in inflammation, possibly in attempting to re-establish homoeostasis.

  • periodontitis
  • proinflammatory cytokines
  • rheumatoid arthritis