Title: Investigating lung epithelial progenitor cell fate in the developing human lung
Funder: The Academy of Medical Sciences

Abstract: Chronic lung disease is a major public health problem and therapy is primarily supportive with transplant being the only definitive treatment. Therapeutic lung regeneration is therefore a long-term goal of many research programmes. Defining the lineage relationships between progenitor cells and mature airway epithelial cells in the human embryonic lung will inform regeneration strategies (including iPSC differentiation) and help understand disease processes where developmental pathways are recapitulated. This application will address the hypothesis that embryonic human lung epithelial tip cells are multipotent and can contribute to all airway lineages in the organoid model. The independent aims will test my specific hypothesis and provide me with the opportunity to learn organoid techniques, cutting-edge lineage analysis, and human genetic manipulation established in my host laboratory. I will add these new skills to my established techniques in lung fibrosis, preparing to investigate the disturbed airway cell lineage seen in fibrotic lung disease. Aim 1: Characterise the kinetics of airway differentiation in human tip organoid cultures Aim 2: Define lineage relationships between progenitor cells and differentiated airway cells using lineage tracing in organoid culture. Aim 3: Examine in vivo spatial distribution of markers of progenitors/intermediate states defined by lineage tracing The data generated by image-based and barcode single-cell lineage tracing will provide information on fate trajectories and will also be used for future studies to identify molecular mechanisms controlling airway fate specification. Defining progenitor-airway cell hierarchy and the mechanisms controlling fate specification may present new therapeutic targets for modulation of tissue remodelling.

Lay abstract: There are very few options to stop or reverse the decline of chronic lung disease. Is it possible to rebuild areas of damaged lung to improve patients’ quality of life? To regenerate adult lung, we need to understand how the lungs are ‘built’ in babies in the womb. We currently don’t understand the origin of the different cell types that line the airways in human lung development. The host laboratory has identified a lung tip progenitor cell in embryonic human lung which can grow indefinitely in culture. I will ask whether these lung tip progenitor cells can differentiate into all cell types seen in the human airway. I will explore if every tip cell has the potential to differentiate into all types of airway cell, or whether their fate is restricted. To do this, I will track individual tip cells in airway differentiation conditions using fluorescent and genetic markers. From these experiments, I aim to draw a map of how and when tip progenitor cells differentiate into airway cells. I will use these data to identify pathways and genes which control the fate of the tip cells. In the longer term, I plan to establish my own research team to determine why developmental pathways are re-activated in chronic lung disease and whether they can be modulated. These experiments will also inform regeneration research by guiding differentiation of stem cells into mature airway cells to model lung diseases ‘in a dish’ and identify new drug targets to improve lung repair.

Research activity codes: 1.1 NORMAL BIOLOGICAL DEVELOPMENT AND FUNCTIONING;2.1 BIOLOGICAL AND ENDOGENOUS FACTORS
Health categories: RESPIRATORY