Ferroptosis Mediates the Progression of Hyperuricemic Nephropathy by Activating RAGE Signaling.

Aims: Hyperuricemic nephropathy (HN) represents a prevalent complication of hyperuricemia, typified by tubular dysfunction, inflammation, and progressive renal fibrosis with unclear mechanisms. Ferroptosis, an iron-dependent regulated cell death, is implicated in multiple diseases, but has rarely been linked to HN. In this study, we aim to explore the possible role of ferroptosis in HN and its underlying mechanisms. Results: We showed that urate oxidase knockout mice, a model of hyperuricemia, exhibited renal impairment with elevated uric acid, creatinine, and blood urea nitrogen levels, accompanied by increased iron deposition and decreased glutathione peroxidase 4 (GPX4) and xCT expressions, suggesting ferroptosis involvement. Ferroptosis inhibitor Ferrostatin-1 (Fer-1) ameliorated renal injury, inflammatory cell infiltration, and fibrosis in these mice. Mechanistically, Fer-1 restored antioxidant protein levels, normalized ferroptosis-associated protein expressions, diminished iron overload and lipid peroxidation, and suppressed inflammatory markers and mitogen-activated protein kinase signaling. In vitro, monosodium urate crystals induced ferroptosis in human kidney 2 cells, characterized by increased lipid peroxidation and iron accumulation. Notably, receptor for advanced glycation end products (RAGE) inhibition alleviated renal injury, inflammation, and fibrosis albeit without directly diminishing ferroptosis. These findings were validated in human hyperuricemia-related kidney disease samples showing increased iron deposition, decreased GPX4, and elevated RAGE expression. Innovation and Conclusion: This study suggests that ferroptosis may play a role in the development of renal injury, inflammation, and fibrosis in HN, potentially mediated through RAGE signaling. While RAGE inhibition improved renal injury, it did not directly affect ferroptosis, indicating a complex and context-dependent role of RAGE in kidney injury. These findings highlight ferroptosis and its associated pathways, including RAGE signaling, as potential therapeutic targets for HN. Antioxid. Redox Signal. 43, 56-74.