Efficacy of nicotiflorin in ameliorating septic acute kidney injury: the role of PINK1/parkin in mitochondrial restoration and oxidative stress reduction

Objectives: Nicotiflorin has demonstrated efficacy in mitigating acute liver injury, and therefore, its potential in treating septic acute kidney injury (AKI) merits further investigation. This study evaluated whether nicotiflorin restores mitochondrial function and reduces oxidative stress in septic AKI via mediating the PTEN-induced putative protein kinase 1 (PINK1)/Parkin signaling pathway. Methods: Lipopolysaccharide (LPS) was applied to replicate septic AKI in C57BL/6 mice and NRK-52E cells, which were later treated with nicotiflorin. Renal function was assessed through biochemical markers, histopathology, and immunofluorescence. The impact of nicotiflorin on cell viability, apoptosis, and mitochondrial function was analyzed using cell counting kit 8 assay and flow cytometry. Mtphagy and Lyso staining was utilized to evaluate the effect of nicotiflorin on mitophagy in LPS-induced cells. Molecularly, Western blot was employed to quantify protein expressions of genes related to apoptosis, mitophagy and oxidative stress in vivo and in vitro. Results: Nicotiflorin treatment significantly improved renal dysfunction, kidney damage, reduced levels of apoptosis-related proteins, increased expressions of PINK1, Parkin, and LC3II/LC3I, and decreased expression of p62 in LPS-induced mice. In NRK-52E cells, nicotiflorin abrogated LPS-triggered reduction in cell viability, increase in apoptosis, elevation in ROS and mitochondrial mass, reduction in mitochondrial membrane potential, upregulation of apoptotic proteins, downregulated NF-E2-related factor-2 (Nrf2), PINK1, Parkin and LC3II/LC3I, and increased expressions of kelch-like ECH-associated protein 1 (KEAP1) and p62. Conclusions: Nicotiflorin attenuates mitochondrial dysfunction and oxidative stress in septic AKI via PINK1/Parkin signaling pathway, suggesting its potential as a therapeutic agent for septic AKI.