[Protective mechanism of urolithin A against alcoholic kidney injury through ferroptosis regulation].

Abstract

Objective To investigate the protective mechanism and molecular targets of urolithin A (UA) against alcohol-induced kidney injury. Methods In animal experiments, alcohol-induced kidney injury was established in mice by gavage with 500 mL/L alcohol [5 g/(kg.d)] for three consecutive days, and different doses of UA were administered to evaluate its protective effects. In additional animal and cell intervention experiments, the silent information regulator 1(SIRT1) inhibitor EX-527 was applied. Commercial kits were used to measure kidney function markers creatinine(CREA), blood urea nitrogen (BUN), oxidative stress markers malondialdehyde(MDA), glutathione(GSH), kidney injury molecule 1 (KIM-1), inflammatory cytokines tumor necrosis factor α(TNF-α), interleukin 1β(IL-1β), and iron content. Western blotting was performed to assess the protein expression levels of glutathione peroxidase 4 (GPx4), cystine/glutamate antiporter (system Xc^-) light chain (xCT), nuclear factor erythroid 2-related factor 2 (Nrf2), and heme oxygenase 1 (HO-1). Network pharmacology was employed to identify the core ferroptosis targets of UA in protecting against kidney injury. Results Alcohol exposure significantly elevated the levels of CREA, BUN, MDA, KIM-1 and inflammatory cytokines, while decreasing GSH level. UA administration markedly alleviated these changes. In addition, UA significantly suppressed the alcohol-induced increase in iron content and the decreases in GPx4, xCT, Nrf2, and HO-1 protein levels. Seven core target molecules were identified through network pharmacology analysis. Inhibition of SIRT1, the core target, significantly antagonized the protective effects of UA on the Nrf2 pathway, ferroptosis, oxidative kidney injury, and renal function at both cellular and animal levels. Conclusion Alcohol exposure induces significant oxidative injury and impairs kidney function. UA activates the Nrf2 signaling pathway via the core target SIRT1, thereby inhibiting ferroptosis and alleviating alcohol-induced oxidative injury and kidney dysfunction.