TGFB1 and pulmonary fibrosis: In summary, we described here the development and thorough characterization of an in vitro lung fibrosis model and demonstrated that it i) works autonomously, i.e., no added pro-fibrotic stimulants such as TGF-β are required; ii) depends on direct EC-FB contact; iii) develops into a fibrotic condition progressively and synchronously; and iv) leads to dynamic phenotype changes of EC and FB that are very similar to cells associated with progressive fibrogenic changes in patients with IPF.