MPO and acute respiratory distress syndrome: LPS-conditioned MH-S cells were treated with miR-29a-1-5p mimic, inhibitor, and RNT4 expression vector, and the ALI animal model was injected with agomir and antagomir of miR-29b-1-5p and RNT4 expression vector, in which the pro-inflammatory cytokine production, cell viability and apoptosis, myeloperoxidase (MPO) activity, wet/dry (W/D) ratio, and expression of TGF-β1, α-smooth muscle actin (α-SMA), E-cadherin, and vimentin were examined.