Nrf2/FSP1/CoQ10 axis-mediated ferroptosis is involved in sodium aescinate-induced nephrotoxicity.

Sodium aescinate (SA), an active compound found in horse chestnut seeds, is widely used in clinical practice. Recently, the incidence of SA-induced adverse events, particularly renal impairment, has increased. Our previous work demonstrated that SA causes severe nephrotoxicity via nephrocyte ferroptosis; however, the underlying mechanism remains to be fully elucidated. In the current study, we investigated additional molecular pathways involved in SA-induced nephrotoxicity. Our results showed that SA inhibited cell viability, disrupted cellular membrane integrity, and enhanced reactive oxygen species (ROS), ferrous iron (Fe2+), and malondialdehyde (MDA) levels, as well as lipid peroxidation in rat proximal renal tubular epithelial cell line (NRK-52E) cells. SA also depleted coenzyme Q10 (CoQ10, ubiquinone) and nicotinamide adenine dinucleotide (NADH) and reduced ferroptosis suppressor protein 1 (FSP1) and polyprenyltransferase (coenzyme Q2, COQ2) activity, triggering lipid peroxidation and ROS accumulation in mouse kidneys and NRK-52E cells. The overexpression of COQ2, FSP1, or CoQ10 (ubiquinone) supplementation effectively attenuated SA-induced ferroptosis, whereas iFSP1 or 4-formylbenzoic acid (4-CBA) pretreatment exacerbated SA-induced nephrotoxicity. Additionally, SA decreased nuclear factor-erythroid-2-related factor 2 (Nrf2) levels and inhibited Nrf2 binding to the -1170/-1180 bp ARE site in FSP1 promoter, resulting in FSP1 suppression. Overexpression of Nrf2 or its agonist dimethyl fumarate (DMF) promoted FSP1 expression, thereby improving cellular antioxidant capacity and alleviating SA-induced ferroptosis. These results suggest that SA-triggers renal injury through oxidative stress and ferroptosis, driven by the suppression of the Nrf2/FSP1/CoQ10 axis.

Sodium aescinate induces renal toxicity by promoting Nrf2/GPX4-mediated ferroptosis.

Sodium aescinate (SA) is extracted from Aesculus wilsonii Rehd seeds and was first marketed as a medicament in German. With the wide application of SA in clinical practice, reports of adverse drug reactions and adverse events have gradually increased, including renal impairment. However, the pathogenic mechanisms of SA have not yet been fully elucidated. The toxic effects and underlying mechanisms of SA were explored in this study. Our data showed that SA significantly elevated the levels of blood urea nitrogen (BUN), serum creatinine (Scr) and Kidney injury molecule 1 (Kim-1), accompanied by pathologically significant changes in renal tissue. SA induced NRK-52E cell death and disrupted the integrity of the cell membrane. Moreover, SA caused significant reductions in FTH, Nrf2, xCT, GPX4, and FSP1 levels, but increased TFR1 and ACSL4 levels. SA decreased glutathione peroxidase (GPx), glutathione (GSH) and cysteine (Cys) levels, but improved Fe2+, malondialdehyde (MDA), reactive oxygen species (ROS) and lipid peroxidation levels, ultimately leading to the induction of ferroptosis. Importantly, inhibition of ferroptosis or activation of the Nrf2/GPX4 pathway prevented SA-induced nephrotoxicity. These findings indicated that SA induced oxidative damage and ferroptosis-mediated kidney injury by suppressing the Nrf2/GPX4 axis activity.