GSE201938
Revisiting the Role of Notch in Nephron Segmentation Confirms A Role for Proximal Fate Selection During Mouse and Human Nephrogenesis
Notch signaling promotes maturation of nephron epithelia, but its proposed contribution to nephron segmentation into proximal and distal domains has been called into doubt. We leveraged single cell and bulk RNA-seq, quantitative immunofluorescent lineage/fate tracing, and genetically modified human iPSC to revisit this question in developing mouse kidneys and human kidney organoids. We confirmed that Notch signaling is needed for maturation of all nephron lineages, and thus mature lineage markers fail to detect a fate bias. By contrast, early markers identified a distal fate bias in cells lacking Notch2, and a concomitant increase in early proximal and podocyte fates in cells expressing hyperactive Notch1 was observed. Orthogonal support for a conserved role for Notch signaling in the distal/proximal axis segmentation is provided by the demonstration that Nicastrin-deficient hiPSCs-derived organoids differentiate into TFA2B+ distal tubule and CDH1 connecting segment progenitors, but not into HNF4A+ or LTL+ proximal progenitors. Overall design: Comparative gene expression profiling analysis of RNA-seq data from kidneys isolated from experimental animals expressing activated Notch1 in nephron progenitors, and control litter mates without Cre.