Hyperoside stabilizes ACAT1 to promote fatty acid oxidation and attenuate kidney fibrosis via the L-carnitine-SIRT3 axis.

Abstract

BACKGROUND: Kidney fibrosis represents a key pathological process driving the progression of chronic kidney disease (CKD) and is closely associated with mitochondrial impairment and altered lipid metabolism. Hyperoside, a major flavonoid glycoside from Abelmoschus manihot, has shown anti-fibrotic activity, yet its mechanistic role in renal fibrosis remains unclear. METHODS: Two murine models, folic acid-induced nephropathy and unilateral ureteral obstruction, were employed to assess the renoprotective actions of hyperoside. Mitochondrial function, lipid metabolic remodeling, and fibrotic progression were examined using histological evaluation, biochemical analyses, and ultrastructural assessment by electron microscopy. Integrated transcriptomic and metabolomic analyses were performed to characterize metabolic pathways modulated by hyperoside. Interaction with ACAT1 was confirmed through cellular thermal shift assays, surface plasmon resonance, and molecular docking. Functional relevance was further established through Acat1 knockdown as well as L-carnitine rescue experiments. RESULTS: Hyperoside markedly reduced renal fibrosis and mitochondrial injury in both mouse models. Multi-omics analyses revealed that hyperoside restored fatty acid oxidation and ketone body metabolism. Mechanistically, hyperoside directly bound to and stabilized mitochondrial acetyl-CoA acetyltransferase 1 (ACAT1), suppressing its ubiquitination and enhancing protein stability and enzymatic activity. This interaction promoted l-carnitine-dependent metabolic flux, which activated the NAD⁺-dependent deacetylase SIRT3. SIRT3 in turn deacetylated superoxide dismutase 2 to reduce reactive oxygen species and facilitated mitophagy-mediated clearance of damaged mitochondria. Acat1 knockdown abolished these metabolic and mitochondrial benefits, whereas l-carnitine partially restored them. CONCLUSIONS: Hyperoside mitigates kidney fibrosis by targeting the ACAT1-l-carnitine-SIRT3 axis to reprogram lipid metabolism, improve mitochondrial functional balance, and strengthen antioxidant capacity. Collectively, these results indicate that hyperoside may serve as a potential mitochondria-focused therapeutic strategy for the treatment of CKD.