TLR4 and acute respiratory distress syndrome: miR-21 (141, 142) and miR-223 (143) worsen SA-ALI by targeting the TLR4/NF-κB pathway, miR-23a-3p targets the Polo-like kinase 1 (PLK1)/STAT1/STAT3 signaling pathway to promote M1 polarization of macrophages (144), and miR-23b mainly targets zonula occludens-1 (ZO-1) to induce vascular leakage and aggravate SA-ALI (145).