Restoration of E-cadherin by PPBICA protects against cisplatin-induced acute kidney injury by attenuating inflammation and programmed cell death.

E-cadherin is a major component of tubular adherent proteins that maintain intercellular contacts and cell polarity in epithelial tissue. It is involved in pathological processes of renal cell carcinoma and fibrotic diseases via epithelial-mesenchymal transition. Although studies have shown E-cadherin is significantly downregulated in acute kidney injury (AKI), its function in AKI is unknown. Here, we evaluated cell damage and inflammation in cisplatin-stimulated tubular epithelial cell lines after disrupting E-cadherin and restoring it with PPBICA, a small molecule identified by high-throughput screening. We also determined the therapeutic potential of restoring E-cadherin in vivo. Results show cisplatin reduced E-cadherin expression both in mouse kidney and proximal tubular epithelial cell lines (mTECs). PPBICA restored E-cadherin levels, which increased cell viability while attenuating programmed cell death. This may be mediated via deactivation of the RIPK1/RIPK3 axis and decreased caspase3 cleavage. In addition, PPBICA suppressed inflammatory response in cisplatin-treated mTECs, which correlated with suppressed NF-κB phosphorylation and promoter activity. In contrast, disruption of E-cadherin promoted cell damage and inflammation. PPBICA failed to further attenuate kidney damage in E-cadherin knockdown cells, indicating that PPBICA protects against mTECs through E-cadherin restoration. We also found that peritoneal injection of PPBICA in mice prevented loss of renal function and tubular damage by suppressing NF-κB-driven renal inflammation and RIPK-regulated programmed cell death. This was driven by restoration of E-cadherin in cisplatin nephropathy. Additionally, PPBICA attenuated cisplatin-induced kidney damage in an established AKI model, indicating its therapeutic potential in the treatment of AKI. In conclusion, E-cadherin plays functional roles in tubule integrity, programmed cell death, and renal inflammation. Our results underscore the potential of E-cadherin restoration as a novel therapeutic strategy for AKI.