Human and Murine Kidneys Contain Transcriptionally and Spatially Orthologous Resident Macrophage Subpopulations in Acute Kidney Injury
Acute kidney injury (AKI) is a major health burden in the United States. Macrophages have been shown to mediate AKI in murine models. Murine kidneys contain multiple subpopulations of kidney resident macrophages (KRM) that are transcriptionally and spatially distinct. We hypothesized the human kidney contains orthologous KRM subpopulations, both transcriptionally and spatially. We utilized kidney sections from donors diagnosed with mild to moderate AKI in order to increase the translatability of murine research to clinical settings. We used spatial transcriptomics and single cell RNA sequencing to identify five distinct human KRM subpopulations. Using the AddModuleScore function in Seurat, we were able to compare the murine KRM transcriptional profiles from pre and post-AKI to the human KRM subpopulations. As a result, we identified four  orthologous to known murine KRM subpopulations. The remaining population was identified in the kidney cortex and expresses a profile similar to activate microglia, the resident macrophage population in the brain. Again, we used AddModuleScore to determine a set of marker genes that will allow for the identification of KRM subsets across species and injury.  Overall design: CD45+ immune cells were isolated from human kidney samples by Fluorescence-activated cell sorting (FACS) and a FITC tagged CD45 antibody. Visium samples include 10 micron sections of human kidneys.