The human cationic host defense peptide LL-37 mediates contrasting effects on apoptotic pathways in different primary cells of the innate immune system

Peter G. Barlow, Yuexin Li, Thomas S. Wilkinson, Dawn M.E. Bowdish, Y. Elaine Lau, Celine Cosseau, Christopher Haslett, A. John Simpson, Robert E.W. Hancock, Donald J. Davidson

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152 Citations (Scopus)


The human cathelicidin LL-37 is a cationic host defense peptide (antimicrobial peptide) expressed primarily by neutrophils and epithelial cells. This peptide, up-regulated under conditions of inflammation, has immunomodulatory and antimicrobial functions. We demonstrate that LL-37 is a potent inhibitor of human neutrophil apoptosis, signaling through P2X 7 receptors and G-protein-coupled receptors other than the formyl peptide receptor-like-1 molecule. This process involved modulation of Mcl-1 expression, inhibition of BID and procaspase-3 cleavage, and the activation of phosphatidylinositol-3 kinase but not the extracellular signal-regulated kinase 1/2 mitogen-activated protein kinase pathway. In contrast to the inhibition of neutrophil apoptosis, LL-37 induced apoptosis in primary airway epithelial cells, demonstrating alternate consequences of LL-37-mediated modulation of apoptotic pathways in different human primary cells. We propose that these novel immunomodulatory properties of LL-37 contribute to peptide-mediated enhancement of innate host defenses against acute infection and are of considerable significance in the development of such peptides and their synthetic analogs as potential therapeutics for use against multiple antibiotic-resistant infectious diseases.

Original languageEnglish
Pages (from-to)509-520
Number of pages12
JournalJournal of Leukocyte Biology
Issue number3
Publication statusPublished or Issued - Sept 2006
Externally publishedYes


  • Antimicrobial peptide
  • Cathelicidin
  • Epithelial cell
  • FPRL-1 P2X
  • Neutrophil

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology
  • Cell Biology

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