Targeting FDX1 with Icaritin attenuates neuronal cuproptosis by reconciling mitochondrial fission-fusion dynamics and bioenergetic homeostasis

Abstract

Copper overload triggers cuproptosis, a copper-dependent cell death pathway characterized by mitochondrial oxidative stress, dysfunction, and disrupted dynamics, posing significant threats to neuronal health. Icaritin (ICT), a bioactive flavonoid from Herbal Epimedii, exhibits antioxidant and neuroprotective properties, but its impact on cuproptosis remains unexplored. Thus, this study was aimed to investigate ICT's protective mechanisms against cuproptosis induced by the cupric sulfate and copper ionophore elesclomol (Cu-ES) in HT22 hippocampal neuronal cells. We found that Cu-ES effectively modeled cuproptosis, reducing viability by 50 % and inducing severe mitochondrial damage, oxidative stress, dysfunction, tricarboxylic acid cycle disruption, and dynamics imbalance. While ICT's treatment concentration-dependently mitigated these injuries. Mechanistically, computational molecular interaction analysis and trajectory simulations, and surface plasmon resonance confirmed ICT directly binds ferredoxin 1 (FDX1) with high affinity and stability, downregulating its protein expression. ICT consequently inhibited the FDX1-mediated cuproptosis pathway, reducing dihydrolipoamide S-acetyltransferase (DLAT) oligomerization, modulating cuproptosis sensitivity proteins, restoring copper homeostasis by increasing ATPase copper transporting beta (ATP7B) and decreasing solute carrier family 31 member 1 (SLC31A1), and suppressing the lipoylation pathway. Crucially, FDX1 knockdown abolished Cu-ES toxicity and potentiated ICT's protective effects against superoxide production, DLAT expression, and copper accumulation. Furthermore, ICT rescued mitochondrial dynamics by promoting fusion and inhibiting fission. Our findings demonstrate ICT is a potent inhibitor of neuronal cuproptosis, targeting FDX1 to alleviate mitochondrial oxidative stress, dysfunction, and dynamics disorder, presenting a promising therapeutic strategy.