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Kidney Week

Abstract: FR-PO640

Roles of microRNA in Development and Maintenance of Urothelium

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

  • Kercsmar, Macie M., Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, Ohio, United States
  • Cortado, Hanna H., Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, Ohio, United States
  • Li, Birong, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, Ohio, United States
  • Jackson, Ashley R., Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, Ohio, United States
  • Becknell, Brian, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, Ohio, United States

Group or Team Name

  • Kidney and Urinary Tract Center.
Background

MicroRNA (miRNA) serve essential roles in epithelial cell development, maintenance, and response to injury by modulating mRNA and protein expression, but their function in urothelium remains largely unexplored. To address this knowledge gap, we engineered mice with urothelium-specific constitutive and inducible inactivation of Dicer, an exonuclease required for miRNA biogenesis.

Methods

We generated urothelial Dicer conditional knockout mice by crossing Dicerfl/fl and Upk2Cre or Upk2CreERT2 animals. A tdTomato (tdT) fluorescent protein was expressed in a Cre/LoxP dependent manner from the Rosa26 locus to identify cells in which Dicer inactivation had occurred. Urothelial lineage markers were evaluated by immunofluorescence microscopy, Western blotting and QRT-PCR.

Results

Bladders from control animals displayed the expected urothelial morphology with sequential layers of Krt5+ basal (B) cells, Upk+ intermediate (I) cells, and Upk+; Fabp4+ superficial (S) cells. In contrast, bladders from 3-week-old mice with biallelic inactivation of Dicer exhibited rounded S cells appearance with patchy/discontinuous Fabp4 expression and frequent exfoliation into the bladder lumen. This was increasingly evident at 6 and 9 weeks of life and associated with expansion of Krt14+ progenitor cells and thickening of the B and I cell layers. Conditional inactivation of Dicer in Upk+ cells of 3-week-old mice recapitulated the phenotype of S cell loss and expansion of the remaining urothelial cell layers.

Conclusion

Dicer is dispensable for urothelial formation but serves an essential role in its structural integrity. Ongoing efforts will identify the specific microRNAs responsible for S cell maintenance.

Funding

  • NIDDK Support