Abstract for presentation at Australia and New Zealand Society of Nephrology Annual Scientific Conference

Nephron number and urinary tract histology in Protein Tyrosine Phosphatase Receptor Type delta (Rptp-delta) knockout mice

  • Miss Eleanor Mitchell, Department of Anatomy and Cell Biology, Monash University, Victoria., Australia
  • Dr Noriko Uetani, McGill Cancer Centre, McGill University, Quebec, Canada
  • Dr Michel Tremblay, McGill Cancer Centre, McGill University, Quebec., Canada
  • Dr Yoichiro Iwakura, Center for Experimental Medicine, Institute of Medical Science, University of Tokyo., Japan
  • Prof John Bertram, Department of Anatomy and Cell Biology, Monash University, Australia
  • Dr Georgina Caruana, Department of Anatomy and Cell Biology, Monash University, Victoria., Australia

    • Rptp-delta is a member of the Protein Tyrosine Phosphatase family. In recent microarray experiments, we found Rptp-delta to be differentially expressed in developing mouse kidney and ureter1,2. In the present study, kidneys and ureters from wildtype, heterozygote and homozygote null Rptp-delta mice were examined at postnatal day (P)30. No differences were noted between the heterozygote and wildtype mice. There was a 37% reduction in body weights of Rptp-delta-/- mice compared to Rptp-delta+/+ mice, however it has been previously shown that there is no difference in birth weights3. Similarly, 40% and 41% reductions in kidney weight and kidney volume, respectively, between the Rptp-delta-/- and wildtype mice, were observed. Unbiased stereological methods were employed to estimate nephron number, glomerular and kidney volumes, and relative volumes of urothelium, lamina propria and smooth muscle in the ureter. There was a ~16% reduction in nephron number (mean±SD) in the knockouts (11060±1196) compared to wildtypes (13160±1130), but no change in glomerular volume. Relative volumes of ureter tissues showed no differences between the genotypes. These results indicate that Rptp-delta may play a role in the development of the kidney, but loss of Rptp-delta does not effect the composition of the ureter.

    1 Mitchell EKL, et al. Differential gene expression in the developing mouse ureter. Gene Expr Patterns. 2006 Feb 2; [Epub].
    2 Caruana G, et al. Spatial gene expression in the T-stage mouse metanephros. Gene Expr Patterns. 2006 Mar 14; [Epub].
    3 Uetani N, et al. Impaired learning with enhanced hippocampal long-term potentiation in PTPdelta-deficient mice. EMBO J. 2000 15;19(12):2775-85.

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