Microglia mediate the increase in slow-wave sleep associated with high ambient temperature

Area of Science:

• Neuroscience
• Sleep Science
• Immunology

Background:

• Ambient temperature influences sleep patterns.
• The underlying mechanisms linking temperature and sleep remain largely unknown.
• Microglia, the brain's resident immune cells, are increasingly recognized for their roles beyond immunity, including in neural function and homeostasis.

Purpose of the Study:

• To investigate the role of microglia in the increase of sleep observed at high ambient temperatures.
• To elucidate the cellular mechanisms mediating thermoregulation of sleep.

Main Methods:

• Experimental setup involving controlled ambient temperatures (25°C and 35°C).
• Administration of PLX3397, a colony-stimulating factor 1 receptor (CSF1R) inhibitor, to deplete microglia.
• Quantification of sleep, specifically slow-wave sleep, using established methods.
• Comparison of sleep patterns between control and microglia-depleted subjects at different temperatures.

Main Results:

• A significant increase in slow-wave sleep was observed at 35°C compared to 25°C.
• Treatment with PLX3397 abolished the temperature-dependent increase in sleep.
• Microglia depletion did not affect sleep duration at the lower ambient temperature (25°C).

Conclusions:

• Microglia play a critical role in the homeostatic regulation of sleep in response to elevated ambient temperatures.
• These findings identify microglia as key mediators linking environmental temperature and sleep.
• Targeting microglia may offer novel therapeutic avenues for sleep disturbances related to thermal stress.