Effect of Toll-like receptor 4 inhibitor on LPS-induced lung injury

Toll-like receptor 4 (TLR4) plays important roles in the recognition of lipopolysaccharide (LPS) and the activation of inflammatory cascade. In this study, we evaluated the effect of TAK-242, a selective TLR4 signal transduction inhibitor, on acute lung injury (ALI). C57BL/6J mice were intravenously treated with TAK-242 15 min before the intratracheal administration of LPS or Pam3CSK4, a synthetic lipopeptide. Six hours after the challenge, bronchoalveolar lavage fluid was obtained for a differential cell count and the measurement of cytokine and myeloperoxidase levels. Lung permeability and nuclear factor-kappa B (NF-kappa B) DNA binding activity were also evaluated. TAK-242 effectively attenuated the neutrophil accumulation and activation in the lungs, the increase in lung permeability, production of inflammatory mediators, and NF-kappa B DNA-binding activity induced by the LPS challenge. In contrast, TAK-242 did not suppress inflammatory changes induced by Pam3CSK4. TAK-242 may be a promising therapeutic agent for ALI, especially injuries associated with pneumonia caused by Gram-negative bacteria.