Idiopathic pulmonary fibrosis (IPF) remains a deadly interstitial lung disease (ILD) with treatment options limited by an incomplete understanding of the mechanisms that initiate and perpetuate disease. A growing literature now implicates lung epithelial dysfunction as playing a role in the events that lead to downstream fibroblast activation, culminating in relentless fibrosis. These studies, together with the observation that lung epithelial cells in all forms of IPF display shortened telomeres, suggests that lung epithelial dysfunction may initiate IPF, and accelerated aging phenotypes or telomerase pathway abnormalities likely contribute to this pathogenesis. However, without access to patient-specific human epithelial-mesenchymal model systems, there are limited options for testing hypotheses of how epithelial changes induced by gene polymorphisms or telomerase perturbations might mechanistically contribute to IPF. Here we propose to develop a human organoid-based in vitro model system for the study of IPF. We have established a biorepository of induced pluripotent stem cells (iPSCs) generated from individuals with sporadic or familial pulmonary fibrosis.
In aim 1 we apply this repository by directing the in vitro differentiation of banked IPF iPSCs carrying telomerase mutations (vs normal iPSCs) into various airway and alveolar lung epithelial cells for the purpose of generating a reductionist, epithelial-only 3D culture model of the intrinsic epithelial dysfunction that we posit may initiate pulmonary fibrosis.
In aim 2 we augment the complexity of this model by introducing human organoids composed of iPSC-derived lung epithelia juxtaposed with human mesenchymal lineages in order to model the epithelial-mesenchymal interactions hypothesized to perpetuate IPF. Finally, in aim 3 we test the hypothesis that different telomerase pathway mutations result in shared lung epithelial perturbations, including short telomeres and p53 activation, that then leads to downstream mesenchymal activation.
Idiopathic pulmonary fibrosis (IPF) causes significant morbidity and mortality in the US today. Treatments are often ineffective and the development of novel therapeutics is hampered due to lack of available human in vitro models that are needed to understand pathogenesis or develop novel drug therapies. This proposal develops a new human organoid culture system, using patient-specific cells to model IPF in vitro.