TLR4 signaling pathways regulating inflammation. Abbreviations: AP-1, activator protein 1; cAMP response element-binding protein; ERK, extracellular-signal-regulated kinases; IκB, inhibitor of NF-κB; IKK, IκB kinase; IRF 3, interferon regulatory factor 3; IRAK-1 and IRAK-4, interleukin-1 receptor-associated kinase 1 and 4; JNK, Jun N-terminal protein kinase; LPS, lipopolysaccharide; MAPK, mitogen-activated protein kinase; MyD88, myeloid differentiation factor; NF-κB, nuclear factor-κB; TLR, Toll-like receptor; TAK1, transforming growth factor-β-activated kinase 1; TRAF6, TNF receptor-associated factor 6; TRIF, TIR-domain-containing adaptor protein inducing interferon-β.