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Kidney Week

Abstract: PO1232

Tsc2 Mutation Induces Renal Tubular Cell Nonautonomous Disease

Session Information

Category: Genetic Diseases of the Kidneys

  • 1001 Genetic Diseases of the Kidneys: Cystic

Authors

  • Kumar, Prashant, The University of Tennessee Health Science Center College of Medicine, Memphis, Tennessee, United States
  • Al-Zadjali, Fahad, Sultan Qaboos University, Muscat, Oman
  • Yao, Ying, The University of Tennessee Health Science Center College of Medicine, Memphis, Tennessee, United States
  • Bissler, John J., The University of Tennessee Health Science Center College of Medicine, Memphis, Tennessee, United States
Background

TSC renal cystic disease is poorly understood and has no approved treatment. In a new principal cell-targeted murine model of Tsc cystic disease, the renal cystic epithelium is mostly composed of type A intercalated cells with an intact Tsc2 gene confirmed by sequencing, although these cells exhibit a Tsc mutant disease phenotype.

Methods

We used a newly derived targeted murine model in lineage tracing and extracellular vesicle (EV) characterization experiments and a cell culture model in EV characterization and cellular induction experiments to understand TSC cystogenesis. For the lineager tracing experiments we used Aquaporin-2 Cre, Floxed Tsc2, and Confetti mice in breeding experiments. To characterize the EVs, we used tunable resistive pulse sensing, dynamic light scattering, electron microscopy, and western blot analyses.

Results

Using lineage tracing experiments, we found principal cells undergo clonal expansion but can contribute very few cells to the cyst. We determined that cystic kidneys contain more interstitial EVs than noncystic kidneys, excrete fewer EVs in urine, and contain EVs in cyst fluid. Moreover, the loss of the Tsc2 gene in EV-producing cells greatly changes the effect of EVs on renal tubular epithelium, such that the epithelium develops increased secretory and proliferative pathway activity. We demonstate that the mTORC1 pathway activity is independent form the EV production, and that the EV effects for a single cell line can vary significantly. mTORC1 inhibition reduces EV production.

Conclusion

TSC cystogenesis involves significant contribution from genetically intact cells conscripted to the mutant phenotype by mutant cell derived EVs.

Funding

  • Other U.S. Government Support