Alveolar budding organoids as a novel drug discovery platform for dysregulated epithelial repair in pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) presents with dysregulated alveolar repair and accumulation of aberrant cell fates supposedly driving the onset and progression of the disease. Standard of care therapies only achieve to decelerate fibrosis, while regeneration of the gas-exchange unit continues to pose a significant challenge. To address the unmet medical need for regenerative concepts, we designed an organoid model of the human alveolar epithelium for the identification of novel pathobiology in dysregulated lung repair. The model was established using co-cultured human primary alveolar type 2 (AT2) cells and lung fibroblasts in a miniaturized 384-well format. Alveolar budding organoids develop bud-like epithelial monolayers, demonstrating alveolar differentiation, apical-basal polarization and surfactant production. A cytokine cocktail, representative of the pro-fibrotic microenvironment in IPF, was used to simulate dysregulated alveolar repair, with disease-specific phenotypes confirmed via gene expression and proteomics. Pro-fibrotic stimulation of organoids led to suppressed bud formation, increased extracellular matrix generation and significant release of clinically relevant IPF biomarkers (e. g. MMP7, sICAM1). Decreased levels of alveolar markers, such as surfactant proteins, and the rise in aberrant gene signatures (e. g. KRT17), suggest disease-specific phenotypic shifts of epithelial cells under pro-fibrotic conditions. In summary, the alveolar budding organoid model demonstrates IPF-relevant phenotype shifts in a pro-fibrotic environment, offering a drug discovery platform to address novel therapeutic concepts in dysregulated alveolar repair.