Molecular characterization of a precision-cut rat lung slice model for the evaluation of anti-fibrotic drugs

The translation of novel pulmonary fibrosis therapies from preclinical models into the clinic represents a major challenge demonstrated by the high attrition rate of compounds that showed efficacy in preclinical models but demonstrated no significant beneficial effects in clinical trials. Precision-cut lung tissue slice (PCLS) contains all major cell types of the lung and preserves the original cell-cell and cell-matrix contacts. It represents a promising ex vivo model to study pulmonary fibrosis. In this study, using RNA sequencing, we demonstrated that TGFβ1 induced robust fibrotic responses in the rat PCLS model as it changed the expression of genes functionally related to extracellular matrix remodeling, cell adhesion, epithelial-to-mesenchymal transition and various immune responses. Nintedanib, pirfenidone and sorafenib each reversed a subset of genes modulated by TGFβ1 and of those genes we identified 229 genes whose expression was reversed by all three drugs. These genes define a molecular signature characterizing many aspects of pulmonary fibrosis pathology and its attenuation in the rat PCLS fibrosis model. A panel of 12 genes and 3 secreted biomarkers including procollagen I, HA and WISP1 were validated as efficacy endpoints for the evaluation of anti-fibrotic activity of experimental compounds. Finally, we showed that blockade of αV integrins suppressed TGFβ1-induced fibrotic responses in the rat PCLS fibrosis model. Overall, our results suggest that the TGFβ1-induced rat PCLS fibrosis model may represent a valuable system for target validation and to determine the efficacy of experimental compounds. TGFb-treated rat precision-cut lung tissue slices (PCLS) were treated with drug and profiled with RNA-Seq