Scientific article

Endogenous IL-1α is a chromatin-associated protein in mouse macrophages

Published inCytokine, vol. 63, no. 2, p. 135-144
Publication date2013

The cytokine interleukin-1α (IL-1α) is synthesized as a 31kDa peptide that lacks a leader peptide and is not secreted by the conventional secretory pathway. A distinctive characteristic of pro-IL-1α is the presence of a nuclear localization sequence in its amino-terminal moiety that allows its translocation to the nucleus. However no nuclear function(s) of the endogenous pro-IL-1α has been reported to date. In the present study, we used murine macrophages that produce IL-1α in response to pro-inflammatory stimuli, to gain further insight into the biology of the endogenous IL-1α protein in innate immune cells. We show that endogenous IL-1α is essentially found as a chromatin-associated nuclear protein in LPS-stimulated macrophages. In contrast to IL-1β, IL-1α was not released upon inflammasome activation unless significant cell damage occurred. IL-1β mRNA and protein levels were specifically decreased in IL-1α deficient macrophages after LPS stimulation. However, overexpression of human pro-IL-1α did not rescue this defective IL-1β production, suggesting that this finding might be related to the insertion of the targeting construct into the IL-1 locus, rather than to a specific nuclear function of pro-IL-1α. Finally, by using both genomic and proteomic approaches, we could not identify a nuclear function of IL-1α. Taken together, these observations suggest that in macrophages IL-1α primarily acts as an alarmin that is rapidly released upon cell damage to activate early mechanisms of host defense.

  • Animals
  • Cell Line
  • Cell Nucleus
  • Chromatin/metabolism
  • Humans
  • Immunity, Innate
  • Inflammasomes/immunology/metabolism
  • Interleukin-1alpha/deficiency/genetics/metabolism
  • Interleukin-1beta/biosynthesis/metabolism
  • Lipopolysaccharides
  • Macrophage Activation
  • Macrophages/immunology/metabolism
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
Citation (ISO format)
LAMACCHIA, Céline et al. Endogenous IL-1α is a chromatin-associated protein in mouse macrophages. In: Cytokine, 2013, vol. 63, n° 2, p. 135–144. doi: 10.1016/j.cyto.2013.04.010
Main files (1)
Article (Published version)
ISSN of the journal1096-0023

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