NODs in defence: from vulnerable antimicrobial peptides to chronic inflammation

Trends Microbiol. 2006 Oct;14(10):432-8. doi: 10.1016/j.tim.2006.08.008. Epub 2006 Aug 30.


Defensins and cathelicidins are prevalent and essential gastrointestinal cationic antimicrobial peptides (CAPs). However, these defensive peptides are not infallible because certain enteropathogens can overcome their protective function. Furthermore, impaired defensin synthesis has been linked to the occurrence of Crohn's disease (CD), a chronic inflammatory bowel disease. Recently, defective bacterial sensing through NOD1 and NOD2 has been related to reduced defensin production, CD predisposition and susceptibility to enteric infection. Hence, we propose that microbial sensors at the gut interface monitor the levels of these effector peptides, which might function as "danger" signals to confer tolerance and alert immunocytes. Further work is required to clarify how gastrointestinal CAPs are regulated and to assess their role in maintaining epithelial homeostasis and triggering adaptive immunity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antimicrobial Cationic Peptides / chemistry
  • Antimicrobial Cationic Peptides / genetics
  • Antimicrobial Cationic Peptides / physiology*
  • Crohn Disease / immunology
  • Gastrointestinal Tract / chemistry
  • Gastrointestinal Tract / immunology
  • Humans
  • Inflammatory Bowel Diseases / immunology
  • Inflammatory Bowel Diseases / physiopathology*
  • Molecular Sequence Data
  • Nod Signaling Adaptor Proteins / physiology*
  • Signal Transduction
  • Toll-Like Receptors / immunology


  • Antimicrobial Cationic Peptides
  • Nod Signaling Adaptor Proteins
  • Toll-Like Receptors