The Thrombin-Derived Host Defense Peptide GKY25 Inhibits Endotoxin-Induced Responses through Interactions with Lipopolysaccharide and Macrophages/Monocytes.
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.
Division of Dermatology and Venereology, Department of Clinical Sciences, Lund University, SE-22184 Lund, Sweden; finja.hansen@med.lu.se.
Finja C
FC
Hansen
Division of Dermatology and Venereology, Department of Clinical Sciences, Lund University, SE-22184 Lund, Sweden;
Martina
M
Kalle-Brune
Division of Dermatology and Venereology, Department of Clinical Sciences, Lund University, SE-22184 Lund, Sweden;
Mariena J A
MJ
van der Plas
Division of Dermatology and Venereology, Department of Clinical Sciences, Lund University, SE-22184 Lund, Sweden;
Ann-Charlotte
AC
Strömdahl
Department of Pharmacy, Uppsala University, SE-75123 Uppsala, Sweden;
Martin
M
Malmsten
Division of Infection Medicine, Department of Clinical Sciences, Lund University, SE-22184 Lund, Sweden; and.
Matthias
M
Mörgelin
Division of Dermatology and Venereology, Department of Clinical Sciences, Lund University, SE-22184 Lund, Sweden; Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 308232.
Artur
A
Schmidtchen
D000595:Amino Acid Sequence; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000276:immunology / Q000494:pharmacology*; D002460:Cell Line; D016207:Cytokines / Q000096:biosynthesis; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D008070:Lipopolysaccharides / Q000276:immunology*; D051218:Lymphocyte Antigen 96 / Q000378:metabolism; D008264:Macrophages / Q000187:drug effects* / Q000276:immunology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D048308:Mitogen-Activated Protein Kinase 14 / Q000378:metabolism; D008969:Molecular Sequence Data; D009000:Monocytes / Q000187:drug effects* / Q000276:immunology; D016328:NF-kappa B / Q000378:metabolism; D010446:Peptide Fragments / Q000276:immunology / Q000494:pharmacology*; D010766:Phosphorylation / Q000187:drug effects; D055503:Protein Multimerization; D015398:Signal Transduction / Q000276:immunology; D013917:Thrombin / Q000276:immunology / Q000378:metabolism / Q000494:pharmacology*; D051195:Toll-Like Receptor 2 / Q000276:immunology; D051197:Toll-Like Receptor 4 / Q000276:immunology
D023181:Antimicrobial Cationic Peptides; D016207:Cytokines; C000600278:GKY25 peptide; D008070:Lipopolysaccharides; C411728:Ly96 protein, mouse; D051218:Lymphocyte Antigen 96; D016328:NF-kappa B; D010446:Peptide Fragments; C493486:Tlr2 protein, mouse; C493487:Tlr4 protein, mouse; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D048031:JNK Mitogen-Activated Protein Kinases; D048308:Mitogen-Activated Protein Kinase 14; D013917:Thrombin