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Abstract: FR-PO639

Dot1/H3K79 Pathway Mediates Defective Ureteric Bud (UB) Branching Leading to Renal Hypodysplasia (RHD) in Prorenin Receptor (PRR) PRRUB-/- Mice

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

  • Yosypiv, Ihor V., Tulane University School of Medicine, New Orleans, Louisiana, United States
  • Taylor, Renfang Song, Tulane University School of Medicine, New Orleans, Louisiana, United States
Background

Dot1 is histone methyltransferase specific for Histone 3 lysine 79 (H3K79) that is important for differentiation of collecting duct (CD) cells. Targeted deletion of the Dot1 in the CD principal cells (PCs) in mice represses the acquisition of PC phenotype resulting in polyuria (Wu. JASN, 2013). We tested the hypothesis that RHD and polyuria observed in mice that lack the PRR in the UB lineage (PRRUB-/-) (Song. PLoS ONE, 2013) is due to reduced Dot1/H3 dimethyl K79 (H3m2K79) expression.

Methods

Mutant [Hoxb7Cre+/PRRflox/flox (PRRUB-/-), n=3] and control (PRRUB+/+, n=3) mice were studied on embryonic (E) day E17.5. Dot1 mRNA and protein expression in the kidney was studied by real-time qRT-PCR and immunohistochemistry, respectively. H3m2K79 protein expression was determined by immunohistochemistry and Western blot analysis. The intensity of H3m2K79 and Dot1 immunoreactivity, normalized for surface area of the kidney section, was examined by Slidebook 4.1 software.

Results

Kidney section surface area was smaller in the mutant compared to control mice (220600±20120 vs.533800±72170 pixels, p<0.05). Dot1 mRNA levels were decreased in mutant compared to control mice (0.68±0.06 vs. 1.0±0.01, p<0.01). Dot1 and H3m2K79 immunostaining was reduced in the mutant vs. control kidneys (Dot1: 0.62±0.03 vs. 1.0±0.01, p<0.05; H3m2K79: 0.64±0.04 vs.1.1±0.01. p<0.05.). Western blot analysis revealed decreased H3m2K79 protein levels in mutant compared to control kidneys (1.0±0.06 vs. 1.5±0.02, p<0.05).

Conclusion

We conclude that reduced H3m2K79 methylation by Dot1 in the UB of PRRUB-/- mice contributes, in part, to RHD and polyuria observed in these mice.