Human pulmonary neuroendocrine progenitors in lung injury and disease

About This Grant

PROJECT SUMMARY Pulmonary neuroendocrine cells (NECs) are rare airway neuroepithelial cells with diverse sensory, signaling, and stem cell functions. NECs have recently become one of the better studied rare cell types of the mammalian lung, most notably through mouse studies. Ours and others’ single cell anatomical mapping, lineage studies, and transcriptional profiling in mice have led to a rich understanding of their development molecular diversity, and stem cell and airway repair function, and physiological studies show their function as specialized sensors that modulate breathing. In contrast to this rich understanding of mouse NECs, little is known about human NECs, including their anatomical distribution, structures, progenitor cell function, and response to airway injury and role in repair. Because NE diseases originating from proximal airways have distinct clinical, histologic, and molecular features from those found in the distal airways, we constructed a foundational cell resolution anatomical map and generated initial molecular and proliferative profiles of human NECs to identify NE progenitor cells within their ‘niches’, and to uncover the origin of diverse human NE proliferative disorders. We have discovered extensive anatomical, histological, and molecular diversity in PNECs not modeled in mouse. Using precision cut lung slice (PCLS) cultures from normal adult human lung, we find that a subset of healthy adult human NECs proliferates in distal NEBs. This enables functional interrogation of these putative NE progenitors (NEPr), which we propose to identify and characterize here. We hypothesize that human distal airway NEBs harbor a specialized subset of molecularly and functionally distinct NE progenitors, and we predict human progenitors are activated by airway injury and controlled by a similar mitogenic pathway as in mouse. Here, we propose to use acute injury models to activate NEPr in human lung precision cut lung slice cultures and in whole donor lungs to reveal their molecular profiles and their ‘niches’ by spatial transcriptomics. We predict NEPr are a prominent source of human NE proliferative disorders and pathologies of the distal airways, such as diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH), which we propose to examine here by single cell and spatial transcriptomics. Finally, we will identify the mitogenic pathway regulating distal human NEPr, which could provide therapeutic target(s) for DIPNECH and other distal NEPr disorders. Identification and characterization of NEPr in distal airways would establish a foundation for elucidating their roles in repair and disease, and for creating human organoid and human induced pluripotent stem cell (iPSC) models that accurately model distal human neuroendocrinopathies. This work also provides a strategy for identifying and characterizing the NEPr and associated diseases in other regions of the human lung.