A Preoptic Neurocircuit That Modulates Metabolic Flexibility.

Area of Science:

• Neuroscience
• Metabolism
• Endocrinology

Background:

• Metabolic flexibility is crucial for survival, enabling animals to adapt fuel usage to environmental changes.
• While hormones regulate metabolic flexibility, the central nervous system's role is less understood.
• The anteroventral preoptic area (avPOA) contains neurons involved in torpor and metabolic regulation.

Purpose of the Study:

• To investigate how activating specific neurons in the avPOA influences metabolic fuel selection and utilization.
• To identify the mechanisms by which these neurons control glucose and fatty acid metabolism in peripheral tissues.
• To explore the role of the central nervous system in coordinating whole-body metabolic flexibility.

Main Methods:

• Acute activation of torpor-regulating glutamatergic Adcyap1+ neurons (avPOA Vglut2/PACAP) in mice.
• Measurement of whole-body fuel utilization (glucose vs. fatty acids).
• Assessment of glucose tolerance and insulin sensitivity in skeletal muscle.
• Investigation of the role of corticosterone in mediating metabolic shifts.

Main Results:

• Activation of avPOA Vglut2/PACAP neurons rapidly shifted fuel use from glucose to fatty acids.
• This shift was associated with reduced glucose utilization and selective insulin resistance in skeletal muscle.
• The metabolic reprogramming was partly mediated by corticosterone, independent of direct muscle innervation.
• Silencing these neurons improved glucose tolerance, indicating bidirectional control.

Conclusions:

• A novel neural pathway from the avPOA to skeletal muscle dynamically regulates glucose utilization and metabolic flexibility.
• The central nervous system plays a critical role in coordinating fuel selection and metabolic adaptation.
• Targeting this pathway could offer new strategies for metabolic disease management.