LAUSR

Studies have demonstrated the phenotypic heterogeneity of vascular endothelial cells (ECs) within a vascular bed; however, little is known about how distinct endothelial subpopulations in a particular organ respond to an inflammatory stimulus. We performed single cell RNA-sequencing of 35,973 lung ECs obtained during the baseline state as well as post-injury time points following inflammatory lung injury induced by lipopolysaccharide. Seurat clustering and gene expression pathway analysis identified two major subpopulations in the lung microvascular endothelium, a subpopulation enriched for expression of immune response genes such as major histocompatibility complex genes (immuneEC) and another defined by increased expression of vascular development genes such as Sox17 (devEC). The presence of immuneEC and devEC subpopulations was also observed in non-human primate lungs infected with SARS-CoV-2 and murine lungs infected with H1N1 influenza virus. Following the peak of inflammatory injury, we observed the emergence of a proliferative lung EC subpopulation. Overexpression of Sox17 prevented inflammatory activation in ECs. Thus, there appears to be a" division of labor" within the lung microvascular endothelium with some ECs showing propensity for inflammatory signaling and others for endothelial regeneration. These results provide underpinnings for the development of targeted therapies to limit inflammatory lung injury and promote regeneration.