Figure 1: Wear particles induced TLR signal pathway. TLRs recognize wear particles with adherent PAMPs or DAMPs via MyD88. The binding of TLR and MyD88 phosphorylates IRAK4 which in turn phosphorylates IRAK1. The activation of AP-1 and NF-κB leads inflammatory cytokine production and osteoclast differentiation which contribute to osteolysis.