Microglia are the first line defense of the brain and are constantly looking for infections to fight off. Overactive microglia can cause uncontrolled inflammation within the brain, which can in turn lead to neuronal damage. New research shows that, honokiol (HNK) is able to down-regulate the production of pro-inflammatory cytokines and inflammatory enzymes in activated microglia via Klf4, a protein known to regulate DNA.