Toll-like receptor 4–MyD88–NF-κB signaling pathway

The Toll-like receptor 4–MyD88–NF-κB signaling pathway is a central signaling axis in innate immunity, responsible for recognizing pathogens and initiating inflammatory responses. TLR4 detects pathogen-associated molecular patterns (e.g., LPS from bacteria), recruiting the adaptor MyD88 after dimerization. MyD88 then orchestrates a kinase cascade involving IRAKs and TRAF6, leading to activation of NF-κB, a transcription factor that triggers the expression of pro-inflammatory cytokines and chemokines. This response is critical for effective defense against infections but, when dysregulated, contributes to chronic inflammation, metabolic and cardiovascular diseases, cancer, and autoimmune conditions[2][3][5][6]. Drugs targeting this pathway act at multiple levels, either dampening excessive inflammation (by inhibiting TLR4, MyD88, or NF-κB) or enhancing immune responses (as in vaccine adjuvants that activate TLR4). Clinical implications include therapeutic development for sepsis, cancer, metabolic disorders, and immune regulation.

Other names

TLR4-MyD88-NF-κB pathwayTLR4 signaling pathwayTLR4–MyD88-dependent pathway

Inhibition of TLR4: blocks upstream signal initiation, reducing cytokine production Inhibition of MyD88: blocks adaptor-dependent signaling Inhibition of NF-κB: blocks pro-inflammatory gene transcription Agonism/antagonism of TLR4 for vaccine adjuvanticity or immunomodulation