Spatiotemporal Mapping of Glomerular Endothelial Regeneration Identifies Apold1 as an Intrinsic Regulator of Repair

Abstract Endothelial cell (EC) injury is central to the pathogenesis of various renal disorders, highlighting the critical importance of vascular repair for restoring organ health. However, due to limited access to human tissue during active regeneration, the exact reparative processes remain largely unknown. This study aimed to investigate regeneration mechanisms specifically within the glomerular microvasculature by utilizing a selective endothelial cell injury (ECI) model in mice.Lineage tracing identified the origin of regenerating ECs. To uncover the transcriptional dynamics driving these reparative changes, we combined single-cell RNA sequencing and Xenium spatial transcriptomics (ST), mapping distinct glomerular EC (gEC) subpopulations across different phases of injury and recovery. Apold1 emerged as a key regulatory candidate within this process. To functionally validate this gene's specific role during the regenerative phase, Apold1-deficient (Apold1-/-) mice underwent the ECI model. After showing that gECs regenerate primarily from local, pre-existing renal ECs, our transcriptomic analysis identified 10 distinct gEC subpopulations and revealed a complex temporal pattern of regeneration. This process begins with the expression of genes associated with inflammation, followed sequentially by endothelial cell (EC) migration, the activation of immediate early genes, vascular remodeling and cellular proliferation. Within this dynamic process, the EC-specific gene Apold1 was identified as a key regulatory candidate. Apold1-/- mice exhibited impaired endothelial regeneration, characterized by increased endothelial activation and greater immune cell infiltration seven days post-ECI. To our knowledge, this is the first study to elucidate the spatiotemporal mechanisms of glomerular endothelial cell regeneration. By identifying local gECs as the primary source of repair, and stablishing the change in their expression pattern during regeneration, as well as identifying Apold1 as an intrinsic regulator, we have laid the groundwork for future research on renal microvascular disorders.