Selenized Tripterine Phytosomes Alleviate Ferroptosis-Mediated Acute Kidney Injury by Suppressing GPX4 Degradation via the DUSP1/Autophagy Pathway

Ferroptosis, a form of lipid peroxidation-mediated cell death, plays a critical role in acute kidney injury (AKI) progression. Tripterine is an active component isolated from traditional medicinal herbs and exhibits diverse biological and pharmacological activities. However, poor bioavailability and cytotoxicity of tripterine has limited its further clinical application, and the underlying action mechanism of tripterine against AKI remains largely unknown. This study aimed to overcome these shortcomings by formulating tripterine into selenized phytosomes and to investigate the therapeutic effects of selenized tripterine phytosomes (Se@Tri-PTs) on ferroptosis-associated AKI. The data showed that Se@Tri-PTs improved the antioxidant capacity of tripterine while reducing its cytotoxicity. Upon erastin or RSL3 stimulation, Se@Tri-PTs maintained intracellular glutathione levels, decreased lipid ROS generation, and suppressed ferroptosis. Mechanistically, Se@Tri-PTs blocked autophagy-mediated degradation of glutathione peroxidase 4 (GPX4), thereby suppressing ferroptosis. Furthermore, Se@Tri-PTs maintained dual-specificity protein phosphatase 1 (DUSP1) protein levels in erastin-stimulated cells, and DUSP1 knockdown reversed Se@Tri-PTs-mediated inhibition of autophagy and ferroptosis. In line with in vitro results, Se@Tri-PTs administration obviously attenuated folic acid-induced AKI and autophagy-dependent ferroptosis in mice. Collectively, these results indicated that Se@Tri-PTs ameliorated ferroptosis and AKI by preserving DUSP1 levels to block autophagy-mediated degradation of GPX4, highlighting their potential in treating ferroptosis-related diseases.