The Influence of Injury on Toll-Like Receptor Responses
Toll-like receptors (TLRs) are a family of evolutionarily conserved cell-surface and intracellular receptors that react to bacterial or viral antigens or to endogenous factors released during cell injury. The ability to recognize a variety of common microbial antigens and endogenous factors indicates that a primary function of TLRs is to act as sentinel receptors to alert the innate immune system to infection or tissue damage. Once triggered, TLRs initiate strong inflammatory responses and set in motion innate and adaptive immune responses with the intent to help the infected or injured host combat potentially harmful infections. Because of their established importance in signaling infections, the microbial ligands for TLRs have been studied more extensively than the endogenous stress-or injury-induced TLR ligands. Nevertheless, the interplay between tissue injury and TLR responses could potentially be as important as their role in signaling microbial responses. This chapter will discuss recent advances in our understanding of the role TLRs play in signaling or regulating the injury response.