Highlights d A single-cell EC atlas of healthy murine tissues d This study provides an interactive webtool for comparative analyses and data exploration d Characterization of inter-and intra-tissue EC heterogeneity d Discovery tool for characterization of ECs in other datasets

Highlights d We single-cell RNA-sequenced 56,771 endothelial cells (ECs) from human, mouse, and cultured lung tumor models d Tip ECs were resolved into migratory and basementmembrane remodeling phenotypes d Capillary and venous ECs expressed immunoregulatory gene signatures d Integrated analysis identified collagen modification as an angiogenic pathway

Highlights d Single-cell RNA-seq reveals EC heterogeneity in choroidal neovascularization d ECs display metabolic transcriptome heterogeneity in the cell cycle and quiescence d Data integration with a genome-scale metabolic model identifies angiogenic targets d SQLE and ALDH18A1 are validated as metabolic angiogenic candidates

In the original article, the surname of co-author Wouter Everaerts was spelled incorrectly as "Everaert." It appears correctly in this Correction, and the error has been corrected online.

BackgroundRenal endothelial cells from glomerular, cortical, and medullary kidney compartments are exposed to different microenvironmental conditions and support specific kidney processes. However, the heterogeneous phenotypes of these cells remain incompletely inventoried. Osmotic homeostasis is vitally important for regulating cell volume and function, and in mammals, osmotic equilibrium is regulated through the countercurrent system in the renal medulla, where water exchange through endothelium occurs against an osmotic pressure gradient. Dehydration exposes medullary renal endothelial cells to extreme hyperosmolarity, and how these cells adapt to and survive in this hypertonic milieu is unknown.MethodsWe inventoried renal endothelial cell heterogeneity by single-cell RNA sequencing >40,000 mouse renal endothelial cells, and studied transcriptome changes during osmotic adaptation upon water deprivation. We validated our findings by immunostaining and functionally by targeting oxidative phosphorylation in a hyperosmolarity model in vitro and in dehydrated mice in vivo.ResultsWe identified 24 renal endothelial cell phenotypes (of which eight were novel), highlighting extensive heterogeneity of these cells between and within the cortex, glomeruli, and medulla. In response to dehydration and hypertonicity, medullary renal endothelial cells upregulated the expression of genes involved in the hypoxia response, glycolysis, and—surprisingly—oxidative phosphorylation. Endothelial cells increased oxygen consumption when exposed to hyperosmolarity, whereas blocking oxidative phosphorylation compromised endothelial cell viability during hyperosmotic stress and impaired urine concentration during dehydration.ConclusionsThis study provides a high-resolution atlas of the renal endothelium and highlights extensive renal endothelial cell phenotypic heterogeneity, as well as a previously unrecognized role of oxidative phosphorylation in the metabolic adaptation of medullary renal endothelial cells to water deprivation.