Attenuation of Proximal Tubule Injury and Kidney Fibrosis with Canagliflozin in a Nonalbuminuric Calcineurin Inhibitor Nephrotoxicity Mouse Model

Background: Whether and how SGLT2 inhibitors mitigate calcineurin inhibitor (CNI) nephrotoxicity is largely unknown since patients post transplantation and those using immunosuppressants were excluded from most large clinical trials. We recently found that injured proximal tubule cells with impaired cellular metabolism were responsible for kidney fibrosis after the chronic use of CNI. We tested whether canagliflozin attenuates proximal tubule injury and kidney fibrosis in a non-albuminuric CNI nephrotoxicity mouse model. Methods: ICR mice received 30 mg/kg/day cyclosporin A (CsA) and were fed a low-salt diet with or without 0.03% (w/w) canagliflozin for 4 weeks. Blood and kidneys were collected and subjected to serological and histological analyses. To characterize the transcriptional changes in the kidneys in an early stage of the disease, kidneys from mice that received either CsA or vehicle and low-salt diet with or without canagliflozin for 1 week (n = 4 each) were subjected to bulk RNA-seq. Using our recent single-nucleus RNA-seq data of kidneys from the CNI nephrotoxicity mouse model and its control, bulk RNA-seq data were deconvoluted to estimate the cell type composition with two different computational pipelines: Bisque and CIBERSORTx. Results: After 4 weeks of canagliflozin administration in the chronic CNI nephrotoxicity mouse model, the average plasma creatinine and urea nitrogen levels were lower than in the control mice. Kidney fibrosis, evaluated by the area percentage of Sirius red staining on the kidney sections, was weaker in mice that received canagliflozin. Bulk RNA-seq of kidneys from mice that received different interventions for 1 week showed that CsA administration increased the expressions of genes associated with inflammatory response and decreased those related with cellular metabolism. Canagliflozin administration reversed these transcriptomic changes in mice receiving CsA. Cell type deconvolution estimated that the proportion of KIM-1–positive injured proximal tubule cells was significantly increased by CsA administration but almost normalized when canagliflozin was administered alongside CsA. Conclusion: Canagliflozin attenuates CsA-induced kidney fibrosis, proximal tubule injury, and the changes in the expression levels of genes associated with inflammation and cellular metabolism. Funding: Commercial Support - Mitsubishi Tanabe Pharma Corporation, Government Support – Non-U.S.