Thus, to determine whether Fra-1 regulates pulmonary fibrosis in vivo, Fra-1Δ/Δ and Fra-1+/+ littermates were treated with vehicle or bleomycin, and the early and late fibrotic responses, histological changes, inflammatory cell profiles and proinflammatory cytokines and chemokines associated with this injury were evaluated at 7, 14, and 31 days after bleomycin administration. Here, FOSL1 is linked to pulmonary fibrosis.