Toll-like receptors: novel pharmacological targets for the treatment of neurological diseases

Toll-like receptors (TLRs) are a family of evolutionarily conserved molecules that directly detect pathogen invasion or tissue damage and initiate a biological response. TLRs can signal through two primary intracellular pathways and as such can induce either immuno-stimulatory or immuno-modulatory molecules. Both sides of this twin-edged sword are being examined for their therapeutic potential in combating neurological disease. The immuno-stimulatory properties of TLRs are being used to generate tumor-specific immune responses to CNS tumors while the immuno-modulatory properties are being used to suppress damaging inflammatory responses to stroke. Recently, a third component of TLR signaling has begun to emerge—that of direct neuroprotection. Hence, the TLRs offer novel targets for the treatment of neurological disease.