TLR4 and coinfection: This study first investigates the role of TLR4 in IAV+SA co-stimulated inflammatory injury of pulmonary epithelial cells, followed by a further exploration of TAK-242 (a TLR4 inhibitor) and TLR4 silencing on NF-κB signaling regulation, aiming to elucidate the molecular mechanisms underlying IAV+SA co-infection-induced pulmonary epithelial inflammatory injury.