MMP9 and pulmonary fibrosis: First, we proved that genetic downregulation of Akt can effectively reduce MV-augmented bleomycin-induced EMT and pulmonary fibrosis, as indicated by the diminished markers of vascular leakage and oxidative stress, decreased MMP-9 and PAI-1 production and Akt phosphorylation, decrement of total lung collagen, improved EMT profiles and pathological fibrotic alterations, and micro-CT images.