Abstract: PO1519
Tsc2 Mutation Induces Renal Tubular Cell Nonautonomous Disease
Session Information
- Cystic Kidney Diseases: Mechanisms, Genetics, and Treatment
October 22, 2020 | Location: On-Demand
Abstract Time: 10:00 AM - 12:00 PM
Category: Genetic Diseases of the Kidneys
- 1001 Genetic Diseases of the Kidneys: Cystic
Authors
- Bissler, John J., The University of Tennessee Health Science Center, Memphis, Tennessee, United States
- Kumar, Prashant, The University of Tennessee Health Science Center, Memphis, Tennessee, United States
- Yao, Ying, The University of Tennessee Health Science Center, Memphis, Tennessee, United States
- Al-Zadjali, Fahad, The University of Tennessee Health Science Center, Memphis, Tennessee, United States
Background
Tuberous sclerosis complex is associated with both renal tumors and cysts in most affected patients. The renal cystic disease is poorly understood and has no approved treatment. Using a new principal cell-targeted murine model of the Tsc cystic disease, we found that the renal cystic epithelium was mostly composed of type A intercalated cells with an intact Tsc2 gene by sequencing, though they exhibited a Tsc-mutant disease phenotype. We posited that extracellular vesicles were involved in promoting the intercalated cell phenotype and disease expression.
Methods
We used lineage tracing experiments to understand the tubular cell fate, and dynamic light scattering, tunable resistive pulse sensing, transition electron microscopy and western blot analysis to characterize the extracellular vesicles. We used microarray analysis to characterize the effects of the extracellular vesicles on target tubule cells.
Results
Using lineage tracing experiments, we find that while principal cells are involved and undergo clonal expansion, they contribute a surprisingly small number of cells to the cyst. We identify that cystic kidneys contain more interstitial extracellular vesicles than noncystic kidneys, excrete fewer extracellular vesicles in the urine, and contain extracellular vesicles in the cyst fluid. We demonstrate that the loss of the Tsc2 gene in the cells producing the extracellular vesicles greatly changes the effect of extracellular vesicles on renal tubular epithelium, such that they develop increased secretory and proliferative pathway activity. mTORC1 activity is not the only controller of extracellular vesicles production, but mTORC1 inhibition does reduce the extracellular vesicle production and greatly changes the effect of extracellular vesicles from treated cells. This may be, at least in part, why mTORC1 inhibitors have a beneficial effect in patients.
Conclusion
Taken together, these results contribute to the mechanistic understanding of how genetically intact cells contribute to the disease phenotype.
Funding
- Other U.S. Government Support