Oxidized Albumin Induces Renal Tubular Cell Death and Promotes the Progression of Renal Diseases Through Ferroptosis.

Oxidative stress plays a crucial role in disease pathogenesis. While reactive oxygen species (ROS) directly cause cellular injury, emerging evidence suggests oxidatively modified proteins like albumin may also contribute significantly to tissue damage. Although oxidized albumin (ox-Alb) is linked to renal pathology, the direct effects and mechanisms of ox-Alb on renal cell injury remain unclear. This study was created to address these questions. In mouse models of renal injury initiated by vitamin C/copper or ischemia/reperfusion, levels of serum ox-Alb were significantly elevated. The treatment of albumin with copper/vitamin C increased Alb carbonylation and reduced the number of sulfhydryl groups, causing Alb oxidation. In cultured renal tubular epithelial NRK-52E cells, ox-Alb triggered cell death, associated with increased intracellular albumin accumulation-enhanced cellular protein carbonylation, and p38 MAPK activation. Notably, ox-Alb induced ferroptosis, evidenced by decreased GPX4 and xCT, increased ACSL4, elevated iron and lipid peroxidation, and suppression by deferoxamine and liproxstatin-1. In vivo, administration of ox-Alb exacerbated doxorubicin-induced nephropathy, as indicated by the elevated BUN, creatinine, and proteinuria, and intensified renal ferroptotic responses, including altered GPX4 and ACSL4. Our findings demonstrate that ox-Alb induces renal cell ferroptosis and promotes renal disease progression, suggesting its pivotal pathogenic role in oxidative stress-related kidney diseases.