Abstract
Neuronal synaptic activity relies heavily on mitochondrial energy production, as synaptic transmission requires substantial ATP. Accordingly, mitochondrial dysfunction represents a key underlying factor in synaptic loss that strongly correlates with cognitive decline in Alzheimer's disease and other neurocognitive disorders. Increasing evidence suggests that elevated nitro-oxidative stress impairs mitochondrial bioenergetic function, leading to synaptic degeneration. In this review, we highlight the pathophysiological roles of nitric oxide (NO)-dependent posttranslational modifications (PTMs), particularly S-nitrosylation of cysteine residues, and their impact on mitochondrial metabolism. We focus on the pathological S-nitrosylation of tricarboxylic acid cycle enzymes, particularly α-ketoglutarate dehydrogenase, as well as electron transport chain proteins. This aberrant PTM disrupts mitochondrial energy production. Additionally, we discuss the consequences of aberrant protein S-nitrosylation on mitochondrial dynamics and mitophagy, further contributing to mitochondrial dysfunction and synapse loss. Finally, we examine current strategies to ameliorate S-nitrosylation-mediated mitochondrial dysfunction in preclinical models of neurodegenerative diseases and explore future directions for developing neurotherapeutics aimed at restoring mitochondrial metabolism in the context of nitro-oxidative stress.