TLR9 and acute respiratory distress syndrome: Studies show that Nrf2 by targeting AREs and HO−1, Nrf2 inhibits the production of ROS and HMGB1, playing an important protective role in ALI and other inflammatory diseases, while ROS generation is essential for the release of NETs and HMGB1 interacting with TLR4 and TLR9 and promotes the formation of NETs, and exacerbates inflammation and tissue injury [22, 23, 24].