Levin, L. I. | bioRxiv Science

bioRxiv2024

A longitudinal atlas of post-viral lung regeneration reveals persistent injury-associated cell states

Functional regeneration of the lungs gas exchange surface following injury requires the coordination of a complex series of cell behaviors within the alveolar niche. Using a multi-modal approach, we have mapped the temporal sequencing of mouse lung regeneration after acute viral injury, demonstrating that this response is asynchronously phased across different cellular compartments. This longitudinal atlas of regeneration has produced a catalogue of new cell states that reflect transient and persistent transcriptional alterations in daughter cells as they transit across axes of differentiation. These new cell states include an injury-induced capillary endothelial cell (iCAP) that arises after injury, persists indefinitely, and shares transcriptional hallmarks with both developing lung endothelium and the endothelial aberrations found in degenerative human lung diseases. This comprehensive atlas of lung regeneration provides a foundational resource to understand the complexity of the cellular and molecular responses to injury, reveals the critical importance of capillary endothelium in maintaining and rebuilding the alveolar niche after injury, and correlates these responses to those found in development and human lung diseases.

cell biology↗

bioRxiv2022

Atf3 defines a population of pulmonary endothelial cells essential for lung regeneration

Following acute injury, the capillary vascular bed in the lung must be repaired to reestablish gas exchange with the external environment. Little is known about the transcriptional and signaling factors that drive pulmonary endothelial cell (EC) proliferation and subsequent regeneration of pulmonary capillaries, as well as their response to stress. Here, we show that the transcription factor Atf3 is essential for the regenerative response of the mouse pulmonary endothelium after influenza infection. Atf3 expression defines a subpopulation of capillary ECs enriched in genes involved in endothelial development, differentiation, and migration. During lung alveolar regeneration, this EC population expands and increases expression of genes involved in angiogenesis, blood vessel development, and cellular response to stress. Importantly, endothelial cell-specific loss of Atf3 results in defective alveolar regeneration, in part through increased apoptosis and decreased proliferation in the endothelium. This leads to the general loss of alveolar endothelium and persistent morphological changes to the alveolar niche, including an emphysema-like phenotype with enlarged alveolar airspaces lined with regions that lack vascular investment. Taken together, these data implicate Atf3 as an essential component of the vascular response to acute lung injury that is required for successful lung alveolar regeneration.

cell biology↗