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Abstract: FR-PO638

Notch Signaling Regulates Renal Urothelium Differentiation

Session Information

  • Pediatric Nephrology - II
    November 03, 2023 | Location: Exhibit Hall, Pennsylvania Convention Center
    Abstract Time: 10:00 AM - 12:00 PM

Category: Pediatric Nephrology

  • 1900 Pediatric Nephrology

Authors

  • Rodriguez, Felipe, Nationwide Children's Hospital, Columbus, Ohio, United States
  • Grounds, Kelly, Nationwide Children's Hospital, Columbus, Ohio, United States
  • Alharakeh, Mohammad, Nationwide Children's Hospital, Columbus, Ohio, United States
  • Becknell, Brian, Nationwide Children's Hospital, Columbus, Ohio, United States
  • Jackson, Ashley R., Nationwide Children's Hospital, Columbus, Ohio, United States
Background

Children with congenital urinary tract obstruction (UTO) face limited treatment options and experience high rates of ESKD. The renal urothelium undergoes a protective adaptation during UTO by forming differentiated Uroplakin (Upk) cells. However, little is known about signaling pathways that govern Upk expression and urothelial differentiation within the kidney. The Notch signaling pathway regulates bladder urothelial differentiation and single cell RNAseq data suggest a role in renal urothelium development. The objective of this study was to test the hypothesis that Notch signaling regulates Upk expression and urothelial differentiation in the kidney.

Methods

We generated Hoxb7Cre;RBPJfl/fl (RBPJUB-KO) mice and RBPJfl/fl (controls) to conditionally disrupt Notch signaling. We collected kidneys and bladders from RBPJUB-KO and controls at embryonic, neonatal, juvenile, and adult time points. We confirmed tissue-specific depletion of RBPJ and Notch abrogation using immunofluorescent analysis (IF-A) and RNAscope, respectively. We used IF-A to evaluate markers of urothelial differentiation.

Results

IF-A confirmed efficient RBPJ depletion in renal urothelium and collecting ducts, but not bladder urothelium at all time points in RBPJUB-KO mice. RNAscope confirmed that Notch targets, Hes1 and Hes6, were significantly decreased in RBPJUB-KO renal urothelium compared to controls. IF-A showed that RBPJUB-KO kidneys had significant decreases in Upk at each stage. Ppar-γ - a transcription factor that regulates Upk expression - and its targets were also significantly decreased in RBPJUB-KO kidneys compared to controls.

Conclusion

We have demonstrated that Notch signaling is key to the formation and maintenance of Upk cells in the renal urothelium. Our data also suggest that Ppar-γ signaling in the renal urothelium may be regulated by Notch. Future studies will investigate whether the Notch signaling directly regulates Upk expression or whether Upk expression is regulated by a Notch-dependent Ppar-γ signaling axis.

Funding

  • NIDDK Support