Cell-matrix interactions control biliary organoids polarity,architecture and differentiation and can be exploited to improve modelling of biliary diseases [scRNA-seq]

Diseases of the biliary epithelium (cholangiopathies) are an important cause of morbidity and mortality. Their pathogenesis and treatment remain unclear, in part because of the lack of disease models relevant to humans. 3D biliary organoids hold great promise, however the inaccessibility of their apical pole, and the presence of extracellular matrix (EBM) limit their experimental application. Here we show that when b integrin signaling is inhibited, either by removing the EMC or using blocking antibodies, biliary organoids revert their polarity and expose the apical membrane. Functional, immunohistochemical and TEM studies, along with bulk and single cell transcriptomic demonstrate that organoids in this novel 3D configuration, are less heterogeneous, show increased biliary differentiation, and decreased expression of stem cell markers. This model can be used to study bile transport, interactions with microbial agents, epithelial permeability, cross-talk with other liver and immune cell types and the effect of matrix changes on the biliary epithelium. Overall design: Liver organoids were generated from liver explants (n=4) and were cultured embedded in the ECM (EMB) or suspended in ECM/media mix (10% BME) or without ECM.