PLAU and pulmonary fibrosis: Complementary studies from different laboratories have established a causal role for PAI-1 in pulmonary fibrosis using several models of lung injury (e.g., bleomycin, TGFβ overexpression, and targeted AEC2 injury), a variety of animal species (e.g. mice and rats), and an assortment of approaches to manipulate PAI-1 activity (e.g. transgenic deficiency or over-expression of PAI-1, SiRNA inhibition, and uPA up-regulation)47.