Liquiritin in Chaihu-shugan-san alleviates Parkinson's Disease via PPARα-mediated inhibition of SCD1/FADS2-dependent Ferroptosis

Abstract

Background: Parkinson's disease (PD) is a progressive neurodegenerative disorder with increasing global prevalence. Chaihu-shugan-san (CSS) is a Chinese medicine compound with reported neuroprotective properties. However, the precise bioactive constituents and underlying mechanisms of CSS in the context of PD remain poorly defined.

Purpose: This study aimed to systematically evaluate the therapeutic potential of CSS, characterize its bioactive constituents, and elucidate the potential molecular mechanisms in PD.

Methods: A network pharmacology-bioinformatics framework was established to predict the potential targets of CSS in PD. MPTP-induced PD mouse models were validated by behavioral tests, histopathology (HE staining), immunohistochemistry (IHC), and Western blot (WB). Machine learning and ROC curve analysis pinpointed key ferroptosis-related genes linked to CSS and PD, with functional enrichment highlighting possible pathways. Further validation was performed using IHC, GPx, MDA, and WB assays. UPLC-MS/MS was employed to characterize bioactive CSS components, followed by druggability screening, molecular docking, and molecular dynamics (MD) simulations. In vitro, MES23.5 cells exposed to MPP⁺ were used to evaluate the neuroprotective effects of Liquiritin (LIQ), the principal active compound in CSS, via CCK-8, LDH, oxidative stress markers (GPx, MDA), lipid peroxidation (C11-BODIPY), iron accumulation (FerroOrange), and WB. Additional validation of ferroptosis modulation was performed in vivo and in vitro.

Results: Multidisciplinary investigations employing prediction and experimental validation consistently demonstrated the neuroprotective effects of CSS against MPTP-induced PD mouse. Machine learning, ROC curve analysis and in vivo validation identified CSS ameliorates PD by inhibiting ferroptosis through PPARα activation. Intriguingly, CSS exhibited therapeutic potential by counteracting ferroptosis-triggered PD-like pathological manifestations in mice. Integrated analysis involving UPLC-MS/MS, druggability screening, molecular docking and MD simulations demonstrated LIQ to be a core bioactive compound in CSS. Mechanistic studies revealed that LIQ protects against MPP⁺- or erastin-induced ferroptosis in MES23.5 cells via activation of the PPARα/SCD1/FADS2 pathway. Pharmacological inhibition of PPARα abolished LIQ's protective effects against both ferroptosis and PD progression, definitively establishing PPARα activation as essential for LIQ-mediated neuroprotection.

Conclusion: LIQ, a major bioactive component of CSS, ameliorates PD pathology by inhibiting ferroptosis through activation of the PPARα/SCD1/FADS2 signaling pathway. These findings uncover a novel anti-ferroptosis mechanism and provide a promising therapeutic framework for the prevention and treatment of PD.

Keywords: Chaihu-shugan-san; Ferroptosis; Liquiritin; PPARα; Parkinson's disease.