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Kidney Week

Abstract: SA-PO1018

Mapping the Molecular Atlas of Podocyte Response to Glucocorticoids Using Multi-Omics Analyses

Session Information

Category: Glomerular Diseases

  • 1403 Podocyte Biology

Authors

  • van den Broek, Martijn, Department of Pathology, Radboud University Medical Center, Nijmegen, Gelderland, Netherlands
  • van den Berge, Bartholomeus Tideman, Department of Pathology, Radboud University Medical Center, Nijmegen, Gelderland, Netherlands
  • Schreuder, Michiel F., Department of Pediatric Nephrology, Radboud University Medical Center, Amalia Children's Hospital, Nijmegen, Gelderland, Netherlands
  • Smeets, Bart, Department of Pathology, Radboud University Medical Center, Nijmegen, Gelderland, Netherlands
  • Jansen, Jitske, Institute of Experimental Medicine and Systems Biology. RWTH Aachen University, Aachen, Germany

Group or Team Name

  • Smeets Lab.
Background

Glucocorticoids are the mainstay of therapy for idiopathic nephrotic syndrome (iNS). Glucocorticoids have been found to directly influence podocyte behaviour and morphology, but the exact mechanism is unknown. Understanding this mechanism may help to identify targets for more effective treatment options with fewer side effects compared to glucocorticoids. We established an animal and kidney organoid model of steroid-sensitive NS to dissect the molecular mechanisms of glucocorticoids on podocytes using single-cell ATAC and RNA sequencing.

Methods

We used the puromycin aminonucleoside (PAN) rat model using one intravenous injection of PAN (10mg/100g) and daily intraperitoneal injections of prednisolone (1.5mg/100g). Human induced pluripotent stem cells were used to make kidney organoids, which were injured to various degrees using Adriamycin (ADR; ranging 0.5-2.5 ug/mL) or PAN (ranging 25-100ug/mL) and rescued with prednisolone (ranging 5-100 ug/mL). Single-cell sequencing was performed using the 10X genomics platform.

Results

Increased proteinuria, foot process effacement and increased podocyte specific desmin-protein expression were observed after PAN injection in rats. The injury was partially rescued by prednisolone treatment, whereas higher doses of prednisolone showed more proteinuria and desmin expression. Prednisolone treatment was not able to rescue more severe injury (by higher PAN injection). At the moment we are analysing single-cell ATAC and RNA sequencing data to identify responses in the podocytes to prednisolone. ADR and PAN can both be used to injure podocytes in kidney organoids, confirmed by western blot for autophagy markers and immunofluorescence for podocyte markers and caspase 3. Currently, rescue with prednisolone is tested before single-cell RNA sequencing is used to map molecular changes in the rescued podocytes.

Conclusion

We established a partially glucocorticoid-responsive in vivo model of NS and are currently performing single-cell sequencing to unravel mechanisms involved in prednisolone-induced podocyte recovery. Interestingly, high doses of prednisolone have adverse effects, and when the injury is too severe it cannot be rescued with prednisolone. In human kidney organoids, podocytes can be injured with ADR or PAN and recovery is being tested at the moment.