Introduction:

Our team has set up a model of bronchial epithelium in air-liquid interphase obtained from induced pluripotent stem cells (iPSCs), called iALI. It presents cellular heterogeneity, including contaminants of non-lung origin, as well as an inhomogeneous epithelial structure. This project aims to improve the quality of these models by developing a co-culture approach combining primary bronchial or iPSC-derived fibroblasts and iPSC-derived bronchial progenitors. The aim is to promote progenitor differentiation towards a functional bronchial epithelium, reduce the majority mesenchymal component and improve the structural organization of the resulting tissue.

Method:

The project is based on two parallel phases:

Co-culture is then performed either in direct or indirect contact.

This approach aims to enhance the physiological relevance of the iALI model for the study of lung pathologies and therapeutic screening.

Results:

Co-culture experiments yielded a functional bronchial epithelium, characterized by the presence of an active ciliary beat. A significant increase in the proportion of EpCAM⁺ epithelial cells, CDHR3⁺ ciliated cells and KRT5⁺ basal cells was observed. At the same time, a slight decrease in non-lung cells, expressing HNF4A, PAX6 or PAX8, was noted, indicating improved cell specificity of the model.

Conclusion:

Co-cultures between bronchial epithelial progenitors and fibroblasts, of primary origin or derived from iPSCs, were obtained. Direct co-culture proved the most effective for inducing epithelial differentiation and reducing contaminants. Tissue organization by immunofluorescence and histology is in progress. Ultimately, this model could be made more complex by adding neurons or immunocompetent cells to better reflect the lung environment in vivo.