Objective: Parkinson's disease (PD) is a debilitating neurodegenerative disorder characterized by the progressive loss of dopaminergic neurons in the substantia nigra. Despite extensive research, no definitive cure or effective disease-modifying treatment for PD exists to date. Therefore, the identification of novel therapeutic agents with neuroprotective properties is of utmost importance. Here, we aimed to investigate the potential neuroprotective effects of Carpesii fructus extract (CFE) in both cellular and Caenorhabditis elegans (C. elegans) models of PD.
Methods: The neuroprotective effect of CFE in H2O2- or 6-OHDA-induced PC-12 cells and α-synuclein-overexpressing PC-12 cells were investigated by determining the cell viability, mitochondrial damage, reactive oxygen species (ROS) production, apoptosis, and α-synuclein expression. In NL5901, BZ555, and N2 worms, the expression of α-synuclein, motive ability, the viability of dopaminergic neurons, lifespan, and aging-related phenotypes were investigated. The signaling pathway was detected by Western blotting and validated by employing small inhibitors and RNAi bacteria.
Results: In cellular models of PD, CFE significantly attenuated H2O2- or 6-OHDA-induced toxicity, as evidenced by increased cell viability and reduced apoptosis rate. In addition, CFE treatment suppressed ROS generation and restored mitochondrial membrane potential, highlighting its potential as a mitochondrial protective agent. Furthermore, CFE reduced the expression of α-synuclein in wide type (WT)-, A53T-, A30P-, or E46K-α-synuclein-overexpressing PC-12 cells. Our further findings reveal that CFE administration reduced α-synuclein expression and improved its induced locomotor deficits in NL5901 worms, protected dopaminergic neurons against 6-OHDA-induced degeneration in BZ555 worms, extended lifespan, delayed aging-related phenotypes, and enhanced the ability of stress resistance in N2 worms. Mechanistic studies suggest that the neuroprotective effects of CFE may involve the modulation of the MAPK signaling pathway, including ERK, JNK, and p38, whereas the interference of these pathways attenuated the neuroprotective effect of CFE in vitro and in vivo.
Conclusion: Overall, our study highlights the potential therapeutic value of CFE as a neuroprotective agent in the context of PD. Furthermore, elucidation of the active compounds of CFE will provide valuable insights for the development of novel therapeutic strategies for PD.
Keywords: Caenorhabditis elegans; 6‐OHDA; Carpesii fructus extract; MAPK pathway; PC‐12 cells; Parkinson's disease; α‐Synuclein.
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