Interstitial Notch signaling regulates nephron development via the Gata3-Renin axis in the mouse kidney

Notch signaling in the renal interstitium is known to be required for the formation of mesangial cells and Ren1 (Renin)-expressing cells. However, little is known about how interstitial Notch signaling affects nephron development. We found that blocking Notch signaling in the renal interstitium in mice caused developmental arrest of proximal tubules accompanied by defective formation of mesangial cells. We examined the interstitial Pdgfrb mutant kidney which exhibits a similar mesangial cell defect and found that the Pdgfrb mutant kidney showed normal proximal tubule development, suggesting that the absence of mesangial cells was not the cause of defective proximal tubule development. Our single cell RNA-seq analysis of the interstitial Rbpj mutant kidney showed that a subset of proximal tubule genes were downregulated in the mutant kidney and that Gata3 was downregulated in the mutant interstitium during the development of Ren1-expressing cells. We found that deleting Gata3 in the interstitium caused the loss of Renin and the developmental arrest of proximal tubules, phenocopying the interstitial Notch/Rbpj mutants. Our results suggest that interstitial Notch signaling regulates the development of proximal tubules via the Gata3-Renin axis in the mouse kidney.