Elucidating the role of pioneer transcription factors in human lung airway differentiation

We have recently identified a human airway epithelial progenitor cell expressing high levels of the pioneer transcription factor ASCL1. Our data suggest that these cells are key progenitors during lung development, and we hypothesize that ASCL1 plays an important functional role. We have recently constructed a single cell RNAseq atlas for the developing human lung and predicted the differentiation trajectories (He et al. 2022), many of which differ to those seen in mice. We have also established a human foetal lung organoid system in which the progenitor cells generate heterogeneous progeny (Lim et al., 2023). This organoid system provides an ideal, dynamic model to test hypotheses regarding lineage relationships and progenitor cell function during human lung development.   We will test the hypothesis ASCL1 is necessary for efficient airway differentiation. We propose to use our lung organoid systems, in conjunction with an effective genetic toolbox recently established in our lab for human organoids (Sun et al. 2021) to knock-down ASCL1 transcription. We will also use targeted damID (Southall et al., 2013; Sun et al., 2022) to assess the binding targets of ASCL1 in progenitor cells and during the differentiation of specific lineages.    

He et al., 2022. “A human fetal lung cell atlas uncovers proximal-distal gradients of differentiation and key regulators of epithelial fates.” Cell 185: 4841-4860, doi.org/10.1016/j.cell.2022.11.005  

Lim et al., 2023 “Organoid modelling of human fetal lung alveolar development reveals mechanisms of cell fate patterning and neonatal respiratory disease.” Cell Stem Cell, 30: 20-37, doi.org/10.1016/j.stem.2022.11.013

Southall et al., 2013. “Cell-type-specific profiling of gene expression and chromatin binding without cell isolation: assaying RNA Pol II occupancy in neural stem cells.” Dev Cell, 26: 101-112, doi.org/10.1016/j.devcel.2013.05.020

Sun et al. 2021. “A Functional Genetic Toolbox for Human Tissue-Derived Organoids.” ELife 10 (October). https://doi.org/10.7554/eLife.67886  Sun et al., 2022. “SOX9 maintains human foetal lung tip progenitor state by enhancing WNT and RTK signalling.” EMBO J, 41, e111338, doi.org/10.15252/embj.2022111338