Key findings indicate that AMSCs (1) suppress inflammatory factors; (2) ameliorate pulmonary hemorrhage, edema, and alveolar wall hyperplasia; and (3) mitigate tissue damage via the dual inhibition of TLR4/NF-κB/MAPK and TGF-β/Smad signaling cascades. Here, TLR4 is linked to Pulmonary hemorrhage.