TLR4 and inner ear disorder: This receptor also interacts with endogenous molecules of damaged tissues.9, 10, 11, 12 Upon binding its ligands, Tlr4 recruits adaptor molecules and activates multiple aspects of the inflammatory immune response, including the production of inflammatory molecules and the activation of immune cells via the NF-κB signaling pathway.13, 14, 15 Tlr4 signaling has been implicated in many disease conditions, such as neurodegeneration, brain injury and ischemia.16, 17 In the cochlea, the role of Tlr4 in the pathogenesis of inner ear diseases is unclear.