Pachymic Acid Ameliorates Fructose-Driven Hyperuricemic Nephropathy in Mice by Suppressing Ferroptosis via Activating Nrf2/GPX-4 Pathway

Hyperuricemic nephropathy, a common subtype of chronic kidney disease (CKD), has become an important global public health issue and is closely related to the dramatic increase in fructose consumption. Pachymic acid, the primary active ingredient of the edible fungal herb Poria cocos, has demonstrated the protective capacity against renal injury, but its beneficial effect on hyperuricemic nephropathy remains unclear. In this study, a fructose-diet-induced hyperuricemia nephropathy mouse model was established to reveal the efficacy of pachymic acid in inhibiting hyperuricemic nephropathy the progression. Our results showed that pachymic acid restored abnormal renal function indexes and pathological manifestations such as tubular dilatation and glomerular fibrosis in fructose-fed mice. Transcriptome sequencing results showed marked alterations in glutathione metabolism and ferroptosis signaling pathways in the kidneys of fructose-fed mice after pachymic acid treatment. Mechanistically, pachymic acid activated the Nrf2/GPX-4 signaling pathway by directly binding to Nrf2 and promoting its nuclear translocation, thereby inhibiting ferroptosis, oxidative stress, and inflammatory responses in the kidneys of fructose-fed mice. Consistent results were observed in uric acid-treated HK-2 cells. Notably, both Nrf2 inhibitor ML385 and GPX-4 inhibitor RSL3 treatments reversed the protective effects of pachymic acid against renal injury by suppressing ferroptosis in vitro and in vivo. Summary, our study provides compelling evidence that pachymic acid ameliorates renal injury in fructose-fed mice by inhibiting ferroptosis through targeted activating an Nrf2/GPX-4 pathway, suggesting that dietary supplementation with Poria cocos or pachymic acid might be an effective strategy for CKD prevention, particularly in the subtype of fructose-diet-driven hyperuricemic nephropathy.