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Kidney Week

Abstract: PO1615

Kidney Tubuloids Model Cystinosis and Allow Drug Screening

Session Information

Category: Genetic Diseases of the Kidneys

  • 1002 Genetic Diseases of the Kidneys: Non-Cystic

Authors

  • Yousef Yengej, Fjodor, Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, Utrecht, Netherlands
  • Jamalpoor, Amer A., Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, Utrecht, Netherlands
  • Rookmaaker, Maarten B., Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, Utrecht, Netherlands
  • Ammerlaan, Carola, Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, Utrecht, Netherlands
  • Zaal, Esther A., Division of Cell Biology, Metabolism and Cancer, Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Utrecht, Netherlands
  • Berkers, Celia, Division of Cell Biology, Metabolism and Cancer, Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Utrecht, Netherlands
  • Masereeuw, Rosalinde, Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, Utrecht, Netherlands
  • Janssen, Manoe J., Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, Utrecht, Netherlands
  • Clevers, Hans, Hubrecht Institute – Royal Netherlands Academy of Arts and Sciences and University Medical Center Utrecht, Utrecht, Utrecht, Netherlands
  • Verhaar, Marianne C., Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, Utrecht, Netherlands
Background

Cystinosis causes progressive damage to the kidney and other organs. In cystinosis, a CTNS mutation causes lysosomal cystine accumulation and other metabolic abnormalities including alfa-ketoglutarate (aKG) accumulation in patient cells and serum. Excess KG associates with aggravated apoptosis, abnormal autophagy and proximal tubule dysfunction, suggesting a key role in cystinosis pathology (Jamalpoor et al. BioRXiv 2020). Current treatment with cysteamine reduces cystine and delays, but does not stop, progression of renal insufficiency nor restores tubular dysfunction. Therefore, new therapies are needed. Here, we use patient kidney tubuloids to model cystinosis and to test the efficacy of a novel drug combination.

Methods

Tubuloids were grown from primary renal cells from the urine of two cystinosis patients and compared with two healthy controls. Tubuloid origin and composition were assessed by qPCR and stainings. The effect of cysteamine and/or bicalutamide treatment was studied by a large-scale metabolic screen using LC-MS. Potential toxicity of bicalutamide was tested by measuring ATP levels as proxy for tubuloid viability at increasing doses.

Results

Urine-derived tubuloids consisted of kidney cells (PAX8+p63-) and not urothelium (PAX8-p63+). Tubuloids contained proximal tubule, loop of Henle, distal tubule and collecting duct epithelium. Patient tubuloids showed hallmark cystine accumulation (1.25 ± 0.12 vs. 0.16 ± 0.01 nmol/mg protein in controls, p<0.05). Although cysteamine normalized cystine levels, it failed to restore aKG accumulation. The novel combination of cysteamine with bicalutamide more potently lowered cystine and reduced aKG in tubuloids (aKG peak area reduction of 16-28% with bicalutamide and 21-37% with the combination, both p<0.05). Finally, the used bicalutamide dose did not compromise the viability of cystinotic tubuloids.

Conclusion

Tubuloids model cystinosis in vitro and allow personalized drug screening. Moreover, tubuloids show that the combination of cysteamine and bicalutamide is more effective in normalizing the metabolic abnormalities in cystinosis than cysteamine alone.

Acknowledgements
This work is supported by the partners of RegMedXB, powered by Health Holland, Top Sector Life Sciences & Health and the Dutch Kidney Foundation (grant 150KG19).

Funding

  • Private Foundation Support