Elevated O-GlcNAcylation Enhances Metabolic Rate and Reduces the Excitability of Hypothalamic ARC Neurons in 10-month-old Male Mice.

Aging correlates with alterations in metabolism and neuronal function, which affect the overall regulation of energy homeostasis. Recent studies have highlighted that protein O-GlcNAcylation, a common post-translational modification regulating metabolic function, is linked to aging. In particular, elevated O-GlcNAcylation increases energy expenditure, potentially due to alterations in the neuronal function of the hypothalamic arcuate nucleus (ARC), a key brain region for energy balance and metabolic processes. However, its impact on metabolism and hypothalamic neuronal activity in aged mice remains unknown. This study investigates the effect of elevated O-GlcNAcylation on metabolic rate, motor behaviors, glucose tolerance, and neuronal excitability within the hypothalamic ARC in 10-month-old mice. We demonstrate that Oga^+/- mice with elevated O-GlcNAcylation levels show increased energy expenditure, but do not show significant alterations in motor function or glucose tolerance. Our ex vivo electrophysiology experiments revealed that Oga^+/- mice exhibited a reduced firing rate of hypothalamic ARC neurons, suggesting that the increased metabolism in these mice could be attributed to the reduced activity of ARC neurons. These findings indicate that O-GlcNAcylation plays a crucial role in maintaining metabolic balance and neuronal function in the aging brain.