Structure-dependent functional properties of human defensin 5
Abstract
The mucosal epithelium secretes a variety of antimicrobial peptides that act as part of the innate immune system to protect against invading microbes. Here, we describe the functional properties of human defensin (HD) 5, the major antimicrobial peptide produced by Paneth cells in the ileum, in relation to its structure. The antimicrobial activity of HD-5 against Escherichia coli proved to be independent of its structure, whereas the unstructured peptide showed greatly reduced antimicrobial activity against Staphylococcus aureus. We find that HD-5 binds to the cell membrane of intestinal epithelial cells and induced secretion of the chemokine interleukin (IL)-8 in a concentration- and structure-dependent fashion. Incubation of HD-5 in the presence of tumor necrosis factor alpha further increased IL-8 secretion synergistically, suggesting that HD-5 may act as a regulator of the intestinal inflammatory response.
Abbreviations: HD, human defensin, HNP, human neutrophil peptide, IL, interleukin, TNF, tumor necrosis factor
Keywords: Human defensin 5, Intestinal epithelium, Interleukin 8, TNF-α
PII: S0014-5793(06)01492-X
doi:10.1016/j.febslet.2006.12.036
© 2006 Federation of European Biochemical Societies. Published by Elsevier BV. All rights reserved.
