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

Background 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. Methods We blocked intersititial Notch signaling by deleting Notch genes or Rbpj with Foxd1Cre. We performed single cell RNA-seq analysis with the interstitial Rbpj mutant and control kidneys. In addition, we generated Pdgfrb and Gata3 mutant kidneys by deleting each gene with Foxd1Cre. We examined proximal tubule development in those mutants by immunostaining. Results We found that blocking Notch signaling in the interstitium caused developmental arrest of proximal tubules. To test if the absence of mesangial cells caused the defective proximal tubule development, 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 is 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 Renin+ cells, suggesting that Notch signaling regulates the expression of Ren1 through Gata3. We found that loss of Gata3 in the interstitium caused the loss of Renin and the developmental arrest of proximal tubules. Conclusions Interstitial Notch signaling regulates the development of proximal tubules via the Gata3-Renin axis in the mouse kidney. ### Competing Interest Statement The authors have declared no competing interest.