Seipin modulates Alzheimer's disease pathogenesis by regulating ferroptosis through a glycine-mediated metabolic pathway.

Alzheimer's disease (AD) remains an incurable neurodegenerative disorder with an elusive pathogenesis, where emerging evidence implicates metabolic dysregulation and ferroptosis in neuronal loss. Although the BSCL2 gene, which encodes Seipin, is crucial for lipid metabolism, its specific role in the progression of AD remains undefined. This study employed Mendelian randomization (MR) analysis, in vivo APP/PS1 mouse models, and in vitro BV2 microglial assays to elucidate the mechanistic axis linking BSCL2, metabolites, and ferroptosis in AD. MR analysis demonstrated a causal relationship between genetically predicted elevated BSCL2 expression and an increased risk of AD, partially mediated by glycine. Supporting these genetic findings, stereotactic knockdown of Seipin in the hippocampus of APP/PS1 mice significantly ameliorated cognitive deficits without inducing systemic metabolic toxicity. Mechanistically, Seipin deficiency reduced ferroptosis in both AD mouse brains and Aβ-stimulated microglia, as evidenced by the upregulation of anti-ferroptotic markers (GPX4, Nrf2, HO-1) and the suppression of pro-ferroptotic effectors (ACSL4, NCOA4). Moreover, glycine supplementation partially ameliorated the aggravated ferroptotic phenotype caused by Seipin overexpression, indicating a functional feedback mechanism in which glycine facilitates glutathione synthesis to mitigate Seipin-induced lipid peroxidation. These findings collectively identify Seipin as a novel regulator of ferroptosis in the pathogenesis of AD and underscore the potential of the BSCL2-glycine-ferroptosis axis as a therapeutic target. Future research should aim to elucidate the specific molecular interactions between Seipin and the iron-handling machinery and to validate glycine-based interventions in clinical settings as a means to prevent neurodegeneration.