TGFB1 and acute respiratory distress syndrome: To confirm that effects of exosomal miR-122-5p on the pulmonary endothelial barrier in ARDS were mediated through TGF-β1, HPMECs were treated with recombinant TGF-β1 protein or TGF-β1 neutralizing antibody (TGF-β1-Ab) after an LPS insult.