The Neuroprotective Effects of the Crinoid Natural Compound Rhodoptilometrin in Parkinson’s Disease Experimental Models: Implications for ER Stress and Autophagy Modulation

The pathogenesis of Parkinson's disease (PD) involves cellular processes such as endoplasmic reticulum (ER) stress, unfolded protein response, autophagy imbalance, and apoptosis, and identifying drugs that can regulate these molecular mechanisms may be a potential therapeutic strategy for PD. This study aimed to investigate the potential neuroprotective effects of the marine crinoid-derived natural compound (+)-rhodoptilometrin (RDM). We utilized an <i>in vitro</i> PD experimental model and conducted a biochemical analysis to investigate its potential neuroprotective effects against 6-hydroxydopamine (6-OHDA)-induced toxicity. We also examined its underlying molecular mechanisms, confirmed using the autophagy inhibitor 3-methyladenine. We utilized an <i>in vivo</i> PD model to evaluate motor function and verified the therapeutic effectiveness of the RDM. RDM effectively inhibited apoptosis, reduced ER stress, and enhanced the viability and autophagy of 6-OHDA-induced SH-SY5Y cells. This was evidenced by reductions in GRP78, p-eIF2α/eIF2α, XBP-1s, and C/EBP homologous protein levels alongside enhancements in LC3-related autophagy pathways. <i>In vivo</i> experiments using zebrafish also showed that RDM significantly attenuated the decrease in locomotor activity caused by 6-OHDA, concurrently alleviating GRP78-related ER stress and promoting antiapoptotic BCL2 expression. These findings indicate that RDM exerted neuroprotective effects by attenuating apoptosis, alleviating ER stress, and promoting autophagy pathways. RDM may be a promising antineurodegenerative drug.