Structure-function relationship of the human antimicrobial peptide LL-37 and LL-37 fragments in the modulation of TLR responses
article
Cathelicidins are effector molecules of the innate host defense system that establish an antimicrobial barrier at epithelial interfaces. The human cathelicidin LL-37, in addition to its antimicrobial activity, also exhibits immunomodulatory effects, such as inhibition of pro-inflammatory responses to bacterial LPS in human monocytic cells. In this report, we demonstrate that LL-37 almost completely prevents the pro-inflammatory cytokine release by human peripheral blood mononuclear cells (PBMCs) following stimulation with Toll-like receptor (TLR)4 and TLR2/1 agonists while leaving TLR2/6, TLR5, TLR7 and TLR8 responses unchanged. Modulation of the TLR response by LL-37 occurred at least partly through the MAP kinase pathway via inhibition of p38 phosphorylation. By using an LL-37 library with overlapping sequences, we identified the mid-region of LL-37, comprising amino acids 13–31, as the active domain for the modulation of TLR responses. The mechanism of immunomodulation of LL-37 and LL-37 fragments is lipopoly-saccharide binding. Correlations between the capacity of LL-37 fragments to modulate TLR responses and their physico-chemical properties revealed that cationicity and hydrophobicity are essential for the modulation of LL-37-mediated TLR responses.
Topics
CathelicidinsImmunomodulationMAP kinasesPhysico-chemical propertiesBacterium lipopolysaccharideCathelicidin antimicrobial peptide LL 37CytokineMitogen activated protein kinaseMitogen activated protein kinase p38Toll like receptorToll like receptor 1Toll like receptor 2Toll like receptor 4Toll like receptor 5Toll like receptor 6Toll like receptor 7Toll like receptor 8Antiinflammatory activityAntimicrobial activityArticleCytokine releaseHumanHuman cellHydrophobicityImmunomodulationPeripheral blood mononuclear cellPriority journalProtein phosphorylationStructure activity relationAmino Acid SequenceAntimicrobial Cationic PeptidesCells, CulturedChromatography, High Pressure LiquidCircular DichroismHumansLigandsMolecular Sequence DataSignal TransductionStructure-Activity RelationshipToll-Like ReceptorsBacteria (microorganisms)
TNO Identifier
90032
ISSN
1431-6730
Source
Biological Chemistry, 390(4 (April)), pp. 295-303.
Pages
295-303
Files
To receive the publication files, please send an e-mail request to TNO Repository.