Role of metabolic stress in the selective vulnerability of dopaminergic neurons

Despite decades of research into the environmental, genetic, and physiological factors contributing to Parkinson’s Disease, a cohesive causative mechanism has not yet been achieved. We propose that because dopaminergic neurons are highly metabolically active, metabolic energy decline primarily caused by mitochondrial dysfunction initiates a cascade of cellular events that disrupts catecholamine metabolism, leading to increased oxidative stress, inflammation, and ultimately the selective degeneration of affected neurons. Here, we showed that neurotoxins rotenone and antimycin A (AA), both known inhibitors of the mitochondrial electron transport chain, promote selective dopaminergic neuronal death through mechanisms of metabolic energy decline, increased oxidative stress, and mitochondrial dysfunction. We used mouse dopaminergic hybridoma cell line MN9D cells to model the effects of rotenone and Antimycin A (AA) exposure on mitochondrial function and dopaminergic neuronal death. MN9D cells, which express endogenous tyrosine hydroxylase (TH), the rate-limiting enzyme in dopamine biosynthesis, serve as a robust model for studying the molecular events associated with PD. Furthermore, to identify potential metabolic rescue strategies, we evaluated the neuroprotective effects of sodium propionate, a sodium salt of short-chain fatty acid and metabolic precursor of succinate. Treatment with 200 μM sodium propionate markedly mitigated rotenone- and AA-induced mitochondrial dysfunction, restored ATP levels, and reduced ROS production and accumulation. These findings indicate that mitochondrial toxin-induced dopaminergic degeneration arises primarily from bioenergetic failure and oxidative stress, and that sodium propionate confers neuroprotection by stimulating or sustaining succinate-dependent mitochondrial energy production. This study highlights a mechanistic link between environmental mitochondrial toxins and PD pathogenesis and proposes a novel metabolic intervention strategy targeting mitochondrial bioenergetic restoration.

Author

• Adetuyi, Oluwatosin

Identifier

hdl:10057/56104

OAI identifier oai:identifier

oai:soar.wichita.edu:10057/56104