Calycosin attenuates neuronal ferroptosis in Alzheimer’s disease mice by activating the Nrf2/HO-1 pathway

In this study, we investigated the therapeutic potential of calycosin (from Astragalus) in Alzheimer's disease (AD), focusing on ferroptosis modulation. APP/PS1 mice received 40 mg/kg calycosin for 3 months. Cognitive function was assessed via Morris water maze test. Tau hyperphosphorylation and amyloid-β (Aβ) aggregation were analyzed using immunofluorescence and Western blotting. In vitro, Aβ1-42-treated HT22 neuronal cells were exposed to calycosin. Ferroptosis-related phenotypes were assessed in vivo and in vitro using Prussian blue staining, commercial kits, and Western blotting. The nuclear factor-erythroid factor 2-related factor 2 (Nrf2) signaling was examined by Western blotting. Calycosin treatment significantly improved cognitive deficits in APP/PS1 mice and inhibited Tau hyperphosphorylation and Aβ aggregation. Calycosin attenuated neurotoxicity and Tau hyperphosphorylation in Aβ1-42-treated HT22 cells. Moreover, calycosin inhibited ferroptosis in vivo and in vitro by decreasing iron aggregation and lipid peroxidation, downregulating transferrin receptor expression, and upregulating ferroportin, cystine/glutamate antiporter, and glutathione peroxidase 4 expression. Mechanistically, the anti-ferroptosis effects of calycosin were linked to the activation of the Nrf2-mediated pathway. These findings suggest that calycosin may exhibit neuroprotective effects against neuronal ferroptosis in AD, indicating its potential as a therapeutic candidate for further investigation in AD.