Mrp8 and Mrp14 are endogenous activators of Toll-like receptor 4, promoting lethal, endotoxin-induced shock.
Nat Med
; 13(9): 1042-9, 2007 Sep.
Article
em En
| MEDLINE
| ID: mdl-17767165
ABSTRACT
To identify new components that regulate the inflammatory cascade during sepsis, we characterized the functions of myeloid-related protein-8 (Mrp8, S100A8) and myeloid-related protein-14 (Mrp14, S100A9), two abundant cytoplasmic proteins of phagocytes. We now demonstrate that mice lacking Mrp8-Mrp14 complexes are protected from endotoxin-induced lethal shock and Escherichia coli-induced abdominal sepsis. Both proteins are released during activation of phagocytes, and Mrp8-Mrp14 complexes amplify the endotoxin-triggered inflammatory responses of phagocytes. Mrp8 is the active component that induces intracellular translocation of myeloid differentiation primary response protein 88 and activation of interleukin-1 receptor-associated kinase-1 and nuclear factor-kappaB, resulting in elevated expression of tumor necrosis factor-alpha (TNF-alpha). Using phagocytes expressing a nonfunctional Toll-like receptor 4 (TLR4), HEK293 cells transfected with TLR4, CD14 and MD2, and by surface plasmon resonance studies in vitro, we demonstrate that Mrp8 specifically interacts with the TLR4-MD2 complex, thus representing an endogenous ligand of TLR4. Therefore Mrp8-Mrp14 complexes are new inflammatory components that amplify phagocyte activation during sepsis upstream of TNFalpha-dependent effects.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Choque Séptico
/
Calgranulina A
/
Calgranulina B
/
Endotoxinas
/
Receptor 4 Toll-Like
Tipo de estudo:
Prognostic_studies
Limite:
Animals
/
Humans
Idioma:
En
Revista:
Nat Med
Assunto da revista:
BIOLOGIA MOLECULAR
/
MEDICINA
Ano de publicação:
2007
Tipo de documento:
Article
País de afiliação:
Alemanha