TLR4 and acute respiratory distress syndrome: In lipopolysaccharide (LPS)-induced ALI, LPS binds to Toll-like receptor 4 (TLR4) and stimulates the TLR4-dependent inflammatory responses, including the activation of the TLR4/MyD88/NF-kB and TLR4/TRIF/IRF3 pathways (Togbe et al. 2007; Kuzmich et al. 2017).