TLR9 and Cognitive impairment: Though deficiency of TLR9 exacerbates cognitive impairment and severity of seizures in the brain,24 it has been demonstrated that activation of TLR9 in microglia and astrocytes induces the production of various proinflammatory cytokines in response to CpG DNA25 and activation of TLR9 in astrocytes leads to synaptic protein loss in the brain in chronic hyperglycemia.26