CHAC1 aggravates aldosterone-induced glomerular mesangial cell ferroptosis in diabetic kidney disease.

In diabetic kidney disease (DKD), overactivation of the renin-angiotensin-aldosterone system (RAAS) promotes ferroptosis. However, the specific role of aldosterone-the terminal effector of the RAAS-in regulating ferroptosis pathways in DKD remains poorly understood. In this study, we investigated how hyperaldosteronism modulates ferroptosis in glomerular mesangial cells. Using db/db mice and high-fat diet (HFD)-induced mice as models, we characterized the metabolic disturbances associated with DKD and the concurrent elevation of endogenous aldosterone. In vitro, MES13 SV40 mesangial cells were exposed to high levels of glucose and aldosterone to recreate the DKD microenvironment, thereby enabling the identification of critical pathogenic targets. We found that db/db and HFD-induced mice exhibited elevated endogenous aldosterone levels along with renal ferroptosis. Aldosterone aggravated ferroptosis in glomerular mesangial cells under high-glucose conditions by increasing ROS, lipid peroxidation products, and malondialdehyde (MDA), while reducing intracellular glutathione (GSH). These changes were coincident with upregulation of glutathione-specific γ-glutamyl cyclotransferase 1 (CHAC1) and downregulation of GPX4 in mesangial cells. Pharmacological inhibition with a mineralocorticoid receptor antagonist or a ferroptosis inhibitor, or genetic knockdown of CHAC1, partly reduced lipid peroxidation, lowered intracellular ROS and MDA levels, and elevated GSH levels and GPX4 expression in mesangial cells. Moreover, treatment with ferroptosis agonists suppressed GPX4 expression, whereas CHAC1 knockdown significantly attenuated this effect. Collectively, these findings indicate that aldosterone, in combination with high glucose, promotes ferroptosis-related phenotypes in mesangial cells, accompanied by CHAC1 upregulation and CHAC1-associated GSH/GPX4 dysregulation, thereby impairing GSH/GPX4-mediated antioxidant defense. These results further implicate CHAC1-associated ferroptosis in DKD pathogenesis and suggest that CHAC1 may serve as a key mediator through which aldosterone exacerbates ferroptosis under hyperglycemic conditions.