Critical role of type 1 plasminogen activator inhibitor (PAI-1) in early host defense against nontypeable Haemophilus influenzae (NTHi) infection

► PAI-1 expression is induced by NTHi in lung tissues of mice. ► Early induction of PAI-1 is critical for anti-microbial defense against NTHi. ► NTHi induces PAI-1 via activation of TLR2-MyD88-MKK3-p38 MAPK signaling pathway.