IRAK1 and Alzheimer disease: Interestingly, unlike miR-146a, miR-146b was down-regulated in both the hippocampus and medial frontal gyrus in individuals with AD; the researchers postulate that down-regulation of miR-146b relieves inhibition of IRAK1 and another TLR signaling molecule, TNF receptor-associated factor 6 (TRAF6), triggering the innate immunity pathway which contributes to the activation of microglia and neurodegeneration (Cogswell et al., 2008).