About Toll-like receptors

Toll-like receptors (TLRs) play an important role in innate immunity by recognizing invading pathogens and host-derived danger signals, and initiating the inflammatory response[1]. Several members of the family have been identified in various organisms. In humans, ten isoforms of TLRs are known (TLR1 - TLR10). TLR5, TLR10, TLR4, and the heterodimers of TLR2/TLR1 or TLR2/TLR6 are localized on the cell membrane and bind to their respective ligands at the cell surface. TLR3, TLR7, TLR8 and TLR9 are localized in the endosomes. Binding of the ligand to the receptor initiates intracellular signalling cascades, leading to the immune response and inflammation. TLRs have been shown to act as key players in the development of autoimmune and chronic inflammatory diseases, as well as in pathogen sepsis and cancer[2]. Therefore, targeting of TLRs with both agonists and antagonists represents promising therapeutic strategy.

TLR Signaling

Toll-like receptor signaling. Overview on human Toll-like receptors and their intracellular signaling pathways according to [3].

  1. Kawai, T. and Akira, S., The role of pattern-recognition receptors in innate immunity: update on Toll-like receptors. Nat Immunol, 2010. 11(5): p. 373-84.
  2. Cook, D.N., Pisetsky, D.S., and Schwartz, D.A., Toll-like receptors in the pathogenesis of human disease. Nat Immunol, 2004. 5(10): p. 975-9.
  3. O'Neill, L., Golenbock, D. and Bowie, A., The history of Toll-like receptors — redefining innate immunity. Nat Immunol, 2013. 13(6): p. 453-60.