Abstract
Toll-like receptors (TLRs) activate distinct, yet overlapping sets of signaling molecules, leading to inflammatory responses to pathogens. Toll/interleukin-1 receptor (TIR) domains, present in all TLRs and TLR adapters, mediate protein interactions downstream of activated TLRs. A peptide library derived from TLR2 TIR was screened for inhibition of TLR2 signaling. Cell-permeable peptides derived from the D helix and the segment immediately N-terminal to the TLR2 TIR domain potently inhibited TLR2-mediated cytokine production. The D-helix peptide, 2R9, also potently inhibited TLR4, TLR7, and TLR9, but not TLR3 or TNF-α signaling. Cell imaging, co-immunoprecipitation, and in vitro studies demonstrated that 2R9 preferentially targets TIRAP. 2R9 diminished systemic cytokine responses elicited in vivo by synthetic TLR2 and TLR7 agonists; it inhibited the activation of macrophages infected with influenza strain A/PR/8/34 (PR8) and significantly improved the survival of PR8-infected mice. Thus, 2R9 represents a TLR-targeting agent that blocks protein interactions downstream of activated TLRs.
Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.
Publication types
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Research Support, N.I.H., Extramural
MeSH terms
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Animals
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Cytokines / metabolism
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Disease Models, Animal
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Humans
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Inflammation / genetics
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Inflammation / metabolism
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Inflammation / pathology
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Influenza, Human / genetics*
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Influenza, Human / metabolism
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Influenza, Human / pathology
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Macrophages / metabolism
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Macrophages / pathology
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Membrane Glycoproteins / antagonists & inhibitors
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Membrane Glycoproteins / chemistry*
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Membrane Glycoproteins / genetics*
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Membrane Glycoproteins / metabolism
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Mice
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NF-kappa B / metabolism
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Peptides / chemistry
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Peptides / pharmacology
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Receptors, Interleukin-1 / chemistry*
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Receptors, Interleukin-1 / metabolism
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Recombinant Fusion Proteins / chemistry
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Recombinant Fusion Proteins / genetics*
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Signal Transduction / drug effects
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Toll-Like Receptor 2 / antagonists & inhibitors
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Toll-Like Receptor 2 / chemistry
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Toll-Like Receptor 2 / genetics*
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Toll-Like Receptor 7 / antagonists & inhibitors
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Toll-Like Receptor 7 / chemistry
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Toll-Like Receptor 7 / genetics*
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Toll-Like Receptor 9 / antagonists & inhibitors
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Toll-Like Receptor 9 / chemistry
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Toll-Like Receptor 9 / genetics*
Substances
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Cytokines
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Membrane Glycoproteins
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NF-kappa B
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Peptides
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Receptors, Interleukin-1
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Recombinant Fusion Proteins
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TIRAP protein, mouse
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TLR4 decoy
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Tlr2 protein, mouse
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Tlr7 protein, mouse
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Tlr9 protein, mouse
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Toll-Like Receptor 2
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Toll-Like Receptor 7
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Toll-Like Receptor 9