Protection Against Cellular Toxicity from Rotenone Treatment by the Neuroprotective, Novel Multifunctional Antiparkinsonian Drug D-512

<b>Objective</b>: Exposure to rotenone, a naturally occurring pesticide, has been linked to an increased risk of developing Parkinson's disease (PD). Rotenone strongly inhibits complex I of the mitochondrial respiratory chain, inducing oxidative stress both in vitro and in vivo, ultimately leading to cell death. The objective of this study was to evaluate the cytoprotective effects of the multifunctional agonist D-512 against rotenone-induced toxicity in neuronal PC12 and dopaminergic MN9D cell lines. <b>Methods</b>: Various cell-based assays, including cell viability, antioxidant activity, caspase-mediated apoptosis, and other related assays, were performed. <b>Results</b>: Rotenone was found to be toxic to both dopaminergic MN9D cells and neuronal PC12 cells. However, treatment with D-512 protected both cell types from rotenone-induced toxicity in a dose-dependent manner. Rotenone-induced impairment of mitochondrial membrane potential and increased production of reactive oxygen species were reversed by D-512 treatment. Furthermore, rotenone-induced caspase-mediated apoptotic signaling in MN9D cells was inhibited by D-512. In addition, D-512 restored levels of phosphorylated tyrosine hydroxylase in rotenone-exposed cells across various doses, indicating protection of the dopaminergic system. Finally, rotenone-induced activation of phosphorylated ERK was reversed by D-512 treatment, further supporting its neuroprotective potential. <b>Conclusions</b>: This study demonstrates the ability of D-512 to reverse the toxic effects of rotenone across multiple experimental models. The data presented here are consistent with previously reported neuroprotective properties of D-512. The multifunctional nature of D-512, which combines potent dopamine agonist activity with neuroprotective and other beneficial properties, may address therapeutic needs in PD beyond symptomatic relief and could have potential application across PD subgroups as part of a personalized therapeutic approach.