Protective Role of Holothuria leucospilota Extract Against Amyloid-β Toxicity via Autophagy and Antioxidant Mechanisms in Caenorhabditis elegans Model.

Alzheimer's disease (AD) is a major global health challenge characterized by cognitive decline and neuronal degeneration driven by amyloid-β (Aβ) aggregation and oxidative stress. Given the limited efficacy and adverse effects of current pharmacological therapies, food-derived bioactive compounds have gained increasing attention as potential preventive strategies against neurodegenerative disorders. In this study, we investigated the neuroprotective effects of Holothuria leucospilota extracts using a transgenic Caenorhabditis elegans model of AD. Our results demonstrated that H. leucospilota hexane extract (HLHE) at 500 µg/mL significantly delayed Aβ-induced paralysis and improved chemotaxis behavior. Consistently, HLHE treatment reduced Aβ deposition and decreased both high- and low-molecular weights of Aβ oligomers, as determined by automated Western blot analysis. Additionally, HLHE also reduced reactive oxygen species (ROS) levels. Transcriptomic and RT-qPCR analyses revealed that HLHE enhanced autophagic activity through the upregulation of bec-1 (autophagy initiation) and lysosomal genes (cpr-1, cpr-2, and cpr-5). Furthermore, HLHE activated antioxidant defense pathways via the insulin/IGF-1 signaling (IIS) axis, specifically upregulating genes associated with SKN-1 pathway (pmk-1, skn-1, gst-4, and gst-10) and HSF-1 pathway (hsf-1, hsp-16.1, hsp-12.6, and mtl-1). HLHE also promoted nuclear localization of SKN-1 and increased expression of its downstream target gst-4. Chemical analysis revealed that HLHE contained arachidonic acid (21.12%) and other bioactive lipid compounds as major constituents, suggesting a synergistic role in promoting autophagy and antioxidant responses. Collectively, this study suggests that HLHE confers neuroprotection against Aβ-induced toxicity by activating autophagy and oxidative stress defense mechanisms, supporting its potential development as a food-derived preventive or therapeutic agent for AD.