Dapagliflozin Protects against Cisplatin-Induced AKI on Primary Human Renal Proximal Tubular Epithelial Cells (hRPTECs)

Background: The renal protective effects of SGLT2 inhibitors are widely known. However, the mechanism is not fully clear yet, although reduction of glomerular intraglomerular pressure and other factors are believed to be involved. We hypothesized that the direct actions of SGLT2 inhibitors on the tubular epithelium takes on a significant role to their renal protective effects, and we investigated them in unimmortalized human renal tubular epithelial cells (hRPTECs) in cisplatin induced acute kidney injury. Methods: Our hRPTECs were obtained from the non-tumor kidneys removed from patients with malignancies with written informed concent. Renal cortex was diced and digested. Tubules were seeded on plates. And we obtained human primary renal proximal tubular cells. Then we administered cisplatin with or without dapagliflozin. We evaluated the expression of renal damage marker KIM-1 and other markers. To check the myofibroblast activation, potentially leading to tissue fibrosis through the secretion of paracrine factors from injured hRPTECs, we performed fibrosis bioassay, using culture supernatants with no cisplatin left over, and fibroblasts established from mouse renal cortex. Results: Our hRPTECs express SGLT2 well unlike immortalized RPTEC (RPTEC/TERT). Tubular epithelial cells had increased expression of KIM-1 after cisplatin administration. Culture supernatants from these cells induced fibrosis, indicating injured hRPTECs excretes pro-fibrotic factors. When dapagliflozin administered simultaneously with cisplatin, KIM-1 expression was drastically suppressed, and the fibrosis-inducing effect of the culture supernatant was attenuated. Cisplatin treatment also increased the expression of the immune checkpoint ligand PD-L1, which induces immune tolerance against injured hRPTEC, and dapagliflozin suppressed it. Conclusion: Dapagliflozin relieved cisplatin-induced acute kidney injury and attenuated myofibroblast activation through reducing the secretion of paracrine factors. Our findings demonstrate that dapagliflozin inhibits the progression from AKI to CKD. Immune tolerance may also be involved in these mechanisms. Funding: Private Foundation Support, Government Support – Non-U.S.