Abstract: TH-PO103
Comparative Effects of Cyclosporine and Voclosporin on Primary Human Proximal Tubular Epithelial Cell (PTEC) Gene Expression
Session Information
- AKI: Mechanisms - I
November 02, 2023 | Location: Exhibit Hall, Pennsylvania Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Acute Kidney Injury
- 103 AKI: Mechanisms
Authors
- Aliwarga, Theresa, University of Washington, Seattle, Washington, United States
- Rehaume, Linda M., Aurinia Pharmaceuticals Inc, Edmonton, Alberta, Canada
- Yeung, Catherine K., University of Washington, Seattle, Washington, United States
- Himmelfarb, Jonathan, University of Washington, Seattle, Washington, United States
- Kelly, Edward J., University of Washington, Seattle, Washington, United States
Background
The development of calcineurin inhibitors (CNIs) dramatically changed the face of transplantation, with the majority of solid organ transplant patients prescribed CNI-based therapeutics. Cyclosporine, a CNI that complexes with cyclophilin to competitively inhibit calcineurin phosphatase activity, has significant side effects with chronic nephrotoxicity the primary clinical concern. Cyclosporine related toxic effects include glomerulosclerosis, thrombotic microangiopathy and tubular vacuolization. Voclosporin, a recently approved CNI for treating adults with active lupus nephritis on a background of immunosuppression, is structurally similar to cyclosporine, with improved binding to calcineurin, higher potency and better tolerability.
Methods
To compare the tubular effects of these two CNIs, we exposed cultures of primary human PTEC in either standard 2D tissue culture or when grown in a 3D kidney microphysiological system (MPS).
Results
Exposure to increasing concentrations (0-10 µM) of cyclosporine or voclosporin [HJ1] revealed only minimal toxicity after 48 hr. in 2D culture. Similarly, exposure of MPS to 10 µM voclosporin or cyclosporine for 48 hr. did not significantly increase KIM-1, a urinary biomarker of acute kidney injury, in MPS effluents. To further differentiate these two CNIs, we performed bulk RNAseq analysis from the MPS studies and observed 443 differentially-expressed genes in the cyclosporine-treated MPS versus 45 genes in the voclosporin cohort. Biological process gene ontology analysis revealed 26 significant pathways in the cyclosporine group and none in the voclosporin group with the majority related to cell cycle processes. PTEC were labeled with a GFP-cytochrome C biosensor to monitor mitochondrial responses. Treatment with either CNI at 1 µM for 48 hr. revealed no changes whereas treatment with 10 µM of either CNI resulted in modest changes in mitochondria as measured by signal intensity and complexity of the network.
Conclusion
Ongoing studies include longer term CNI exposures and effects of CYP3A5 genotype as this enzyme is polymorphic, expressed in the kidney and produces isozyme-specific metabolites of cyclosporine. Our results to date support differential effects of voclosporin versus cyclosporine on PTEC gene expression.
Funding
- Other NIH Support – Aurinia Pharmaceuticals