The Bacterial Component Flagellin Induces Anti-Sepsis Protection Through TLR-5, IL-1RN and VCAN During Polymicrobial Sepsis in Mice.

Background: The present study was designed to observe the effects of the bacterial component flagellin on anti-sepsis protection through TLR-5, VCAN and IL-1RN.

Methods: A clinically relevant model of sepsis was induced by cecal ligation and puncture (CLP). An in vitro culture of endothelial cells was analyzed.

Results: Flagellin induced anti-sepsis protection through inhibition of inflammation and induction of endothelial proliferation by down-regulating the expression of TLR 3, TLR 4, and IL-1RN and promoting the expression of VCAN in mice 24 h post-CLP. In vitro, flagellin promoted the proliferation of endothelial cells. These effects could be inhibited by transfection of endothelial cells with VCAN siRNA or IL-1RN over-expression constructs. VCAN expression decreased after transfection of the cells with an IL-1RN over-expression construct and increased after transfection of the cells with an IL-1RN siRNA construct. IL-1RN expression remained unchanged after transfection of the cells with VCAN over-expression or siRNA constructs.

Conclusions: These data suggest that flagellin pretreatment promoted anti-sepsis protection through the TLR-5, IL-1RN and VCAN pathway. This pathway is necessary to mediate endothelial repair and thereby promote survival following sepsis challenge.