Kidney Week

Abstract: FR-PO932

Loss of Dicer Activity in the Peri-Wolffian Duct Stroma Leads to Increased Rates of Vesicoureteral Reflux

Session Information

• Development, Stem Cells, Regenerative Medicine - II
  October 26, 2018 | Location: Exhibit Hall, San Diego Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Development, Stem Cells, and Regenerative Medicine

• 501 Development, Stem Cells, and Regenerative Medicine: Basic

Authors

• Anslow, Melissa J., Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania, United States

Melissa J. Anslow,

• Sims-Lucas, Sunder, Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania, United States

Sunder Sims-Lucas,

• Bates, Carlton M., Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania, United States

Carlton M. Bates,

• Ho, Jacqueline, Children's Hosp of Pittsburgh of UPMC, Pittsburgh, Pennsylvania, United States

Jacqueline Ho,

Background

Vesicoureteral reflux (VUR) is associated with urinary tract infections, hypertension, and reflux nephropathy, a leading cause of pediatric end-stage renal disease. Formation and location of the vesicoureteral junction is determined largely by the induction site of the ureteric bud from the Wolffian duct, which depends mostly on signals from the surrounding stroma. VUR appears heritable, but no single genetic mutation causes most known cases of VUR. miRNAs are small, noncoding RNAs, processed by Dicer, that regulate gene expression post-transcriptionally. We hypothesize that miRNAs are necessary for vesicoureteral junction development and prevention of VUR.

Methods

We generated a transgenic mouse model with loss of Dicer in the peri-Wolffian duct stroma (Tbx18cre; Dicer^Fl/Fl). We performed euthanized cystograms and 3D reconstructions of the ureters and bladder on mutants and controls (Tbx18Cre negative littermates). We performed whole mount Calbindin immunostaining at E11.5 to assess the ureteric bud induction site.

Results

Euthanized cystograms demonstrated significantly higher rates of VUR in the mutant mice compared to control [40% (6/15) of Dicer mutants as opposed to 3.8% (2/52) of controls (p < 0.01)]. 3D reconstructions showed lower ureteral insertions into the bladder and shorter intravesicular tunnel lengths on the side of VUR in mutants compared to control mice and non-refluxing mutant ureters (p < 0.05). Calbindin immunostaining reveals a cranially shifted ureteric bud induction site in E11.5 mutants compared to controls (p < 0.05).

Conclusion

These data suggest for the first time that miRNAs have a role in preventing VUR. This appears due to a requirement for miRNAs in peri-Wolffian duct stroma for normal ureteric bud induction and subsequent ureter insertion into the bladder. Future work will assess molecular mechanisms by which deletion of miRNAs in the peri-Wolffian duct stroma leads to VUR and elucidate which miRNAs in the peri-Wolffian duct stroma are critical for normal ureteric bud induction.

Funding

• NIDDK Support