TY - JOUR

T1 - The Thrombin-Derived Host Defense Peptide GKY25 Inhibits Endotoxin-Induced Responses through Interactions with Lipopolysaccharide and Macrophages/Monocytes

AU - Hansen, Finja C

AU - Kalle-Brune, Martina

AU - van der Plas, Mariena J A

AU - Strömdahl, Ann-Charlotte

AU - Malmsten, Martin

AU - Mörgelin, Matthias

AU - Schmidtchen, Artur

N1 - Copyright © 2015 by The American Association of Immunologists, Inc.

PY - 2015/6/1

Y1 - 2015/6/1

N2 - Host defense peptides have recently gained much interest as novel anti-infectives owing to their ability to kill bacteria and simultaneously modulate host cell responses. The cationic host defense peptide GKY25 (GKYGFYTHVFRLKKWIQKVIDQFGE), derived from the C terminus of human thrombin, inhibits proinflammatory responses in vitro and in vivo, but the mode of action is unclear. In this study, we show that GKY25, apart from binding bacterial LPS, also interacts directly with monocytes and macrophages in vitro, ex vivo, and in vivo. Moreover, GKY25 inhibits TLR4- and TLR2-induced NF-κB activation in response to several microbe-derived agonists. Furthermore, GKY25 reduces LPS-induced phosphorylation of MAPKs p38α and JNK1/2/3. FACS and electron microscopy analyses showed that GKY25 interferes with TLR4/myeloid differentiation protein-2 dimerization. The results demonstrate a previously undisclosed activity of the host defense peptide GKY25, based on combined LPS and cell interactions leading to inhibition of TLR4 dimerization and subsequent reduction of NF-κB activity and proinflammatory cytokine production in monocytes and macrophages.

AB - Host defense peptides have recently gained much interest as novel anti-infectives owing to their ability to kill bacteria and simultaneously modulate host cell responses. The cationic host defense peptide GKY25 (GKYGFYTHVFRLKKWIQKVIDQFGE), derived from the C terminus of human thrombin, inhibits proinflammatory responses in vitro and in vivo, but the mode of action is unclear. In this study, we show that GKY25, apart from binding bacterial LPS, also interacts directly with monocytes and macrophages in vitro, ex vivo, and in vivo. Moreover, GKY25 inhibits TLR4- and TLR2-induced NF-κB activation in response to several microbe-derived agonists. Furthermore, GKY25 reduces LPS-induced phosphorylation of MAPKs p38α and JNK1/2/3. FACS and electron microscopy analyses showed that GKY25 interferes with TLR4/myeloid differentiation protein-2 dimerization. The results demonstrate a previously undisclosed activity of the host defense peptide GKY25, based on combined LPS and cell interactions leading to inhibition of TLR4 dimerization and subsequent reduction of NF-κB activity and proinflammatory cytokine production in monocytes and macrophages.

KW - Amino Acid Sequence

KW - Animals

KW - Antimicrobial Cationic Peptides

KW - Cell Line

KW - Cytokines

KW - Enzyme Activation

KW - Humans

KW - JNK Mitogen-Activated Protein Kinases

KW - Lipopolysaccharides

KW - Lymphocyte Antigen 96

KW - Macrophages

KW - Male

KW - Mice

KW - Mice, Inbred C57BL

KW - Mitogen-Activated Protein Kinase 14

KW - Molecular Sequence Data

KW - Monocytes

KW - NF-kappa B

KW - Peptide Fragments

KW - Phosphorylation

KW - Protein Multimerization

KW - Signal Transduction

KW - Thrombin

KW - Toll-Like Receptor 2

KW - Toll-Like Receptor 4

KW - Journal Article

KW - Research Support, Non-U.S. Gov't

U2 - 10.4049/jimmunol.1403009

DO - 10.4049/jimmunol.1403009

M3 - Journal article

C2 - 25911750

VL - 194

SP - 5397

EP - 5406

JO - Journal of Immunology

JF - Journal of Immunology

SN - 0022-1767

IS - 11

ER -