The inflammasome mediates UVB-induced activation and secretion of interleukin-1beta by keratinocytes

Curr Biol. 2007 Jul 3;17(13):1140-5. doi: 10.1016/j.cub.2007.05.074.


It has long been known that human keratinocytes are a potent source of the proinflammatory cytokines proIL-1alpha and -1beta[1], which are activated and released in response to UV irradiation [2]. However, the intracellular pathways, which regulate maturation and secretion of IL-1 in keratinocytes, are unknown. Here we show that the UVB-mediated enhancement of cytoplasmic Ca(2+) is required for activation of the IL-1beta-converting enzyme caspase-1 by the inflammasome, a multiprotein innate immune complex [3, 4]. Caspase-1 in turn activates proIL-1beta, and keratinocytes secrete the cytokine as well as inflammasome components. These results demonstrate the presence of a proIL-1beta-processing inflammasome in nonprofessional immune cells and the necessity of inflammasome components for the UVB-induced secretion of IL-1beta. This supports the concept that keratinocytes are important immuno-competent cells under physiological and pathological conditions [5].

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcium / metabolism
  • Caspase 1 / metabolism
  • Cytokines / metabolism*
  • Cytoplasm / metabolism
  • Dermatitis / metabolism
  • Humans
  • Inflammation Mediators / metabolism*
  • Interleukin-1 / metabolism*
  • Interleukin-1beta / metabolism*
  • Keratinocytes / metabolism*
  • Keratinocytes / radiation effects
  • Mice
  • Mice, Knockout
  • Multiprotein Complexes / metabolism
  • Protein Precursors / metabolism*
  • Ultraviolet Rays


  • Cytokines
  • Inflammation Mediators
  • Interleukin-1
  • Interleukin-1beta
  • Multiprotein Complexes
  • Protein Precursors
  • interleukin 1 precursor
  • Caspase 1
  • Calcium