Modeling Progressive Fibrosis with Pluripotent Stem Cells Identifies an Anti-Fibrotic Small Molecule

Progressive organ fibrosis accounts for one third of all deaths worldwide, yet preclinical models that mimic the complex, progressive nature of the disease are lacking and hence there are no curative therapies. Progressive fibrosis across organs shares common cellular and molecular pathways involving chronic injury, inflammation, and aberrant repair resulting in deposition of extracellular matrix, organ remodeling and ultimately organ failure. Here we describe the generation and characterization of an in vitro progressive fibrosis model that uses multiple different cell types derived from induced pluripotent stem cells. Our model produces endogenous activated TGF-b and contains activated fibroblastic aggregates that progressively increase in size and stiffness with activation of known fibrotic molecular and cellular changes. We used this model as a phenotypic drug discovery platform for modulators of fibrosis. We validated this platform by identifying a compound that promotes resolution of fibrosis in in vivo and ex vivo models of ocular and lung fibrosis. Overall design: iFA Model (stepwise progression): Examination of aggregate cultures of mesenchymal-like cells from 3 patients at days 4 and 13. iFA Model (AA5 treatment): Comparison of aggregate cultures of mesenchymal-like cells from 2 patients after DMSO-treated, prevention (AA5p) or reversal (AA5r) of iFA phenotype. LSC (AA5 treatment): Comparison of DMSO- and AA5-treated Lung Slice Cultures (LSCs) from end-stage IPF lung tissue obtained at the time of lung transplantation from 6 patients.