Microglia modulate stable wakefulness via the thalamic reticular nucleus in mice

Area of Science:

• Neuroscience
• Immunology
• Sleep Science

Background:

• Microglia are key players in brain homeostasis and immunity.
• The specific role of microglia in regulating vigilance and sleep-wake cycles is not well understood.

Purpose of the Study:

• To investigate the involvement of microglia in the regulation of wakefulness and sleep.
• To elucidate the underlying molecular mechanisms, particularly the role of ceramide signaling.

Main Methods:

• Genetic microglial depletion in mice.
• Physiological monitoring of sleep-wake states.
• Brain metabolomic analysis.
• Chemogenetic manipulation of specific neuronal populations.

Main Results:

• Microglial depletion led to decreased stable nighttime wakefulness and increased wakefulness-NREM sleep transitions.
• Brain ceramide levels showed diurnal variation correlating with sleep-wake behavior, which was abolished upon microglial depletion.
• Ceramide influenced microglia in the thalamic reticular nucleus (TRN), and TRN microglial depletion impaired wakefulness.
• Anterior TRN neurons, modulated by microglia and ceramide, regulate wakefulness-NREM sleep transitions.

Conclusions:

• Microglia modulate stable wakefulness via ceramide signaling in the thalamic reticular nucleus.
• This pathway involves the regulation of anterior TRN neuron activity.
• Targeting microglial ceramide signaling may offer novel therapeutic strategies for sleep disorders.