TLR9 is a receptor for bacterial DNA, in particular for the unmethylated CpG motif, which is increased in NASH models; the activation of TLR9 signaling on Kupffer cells induces the production of proinflammatory cytokine, such as IL-1β leading to steatosis and inflammation. The gene discussed is TLR9; the disease is metabolic dysfunction-associated steatohepatitis.