Astrocyte-derived adenosine modulates increased sleep pressure during inflammatory response

Area of Science:

• Neuroscience
• Immunology
• Sleep Science

Background:

• Sickness behavior, including increased non-rapid-eye-movement (NREM) sleep and slow wave activity (sleep pressure), follows immune system activation.
• Astrocytes play a role in central nervous system immune responses, but their specific contribution to sickness-induced sleep changes is unclear.
• Adenosine signaling is implicated in sleep homeostasis, and systemic infections may increase central adenosine levels.

Purpose of the Study:

• To investigate the role of astrocytes in modulating sleep pressure during immune challenge.
• To determine if astrocyte-derived adenosine signaling mediates the effects of lipopolysaccharide (LPS) on sleep homeostasis.
• To examine the involvement of adenosine receptor 1 (A1R) in LPS-induced sleep changes.

Main Methods:

• Utilized an inducible, astrocyte-specific dominant-negative SNARE (dnSNARE) mouse model to manipulate gliotransmission.
• Administered peripheral lipopolysaccharide (LPS) to mimic systemic infection.
• Measured sleep pressure via slow wave activity during NREM sleep.
• Administered A1R antagonist (CPT) intracerebroventricularly.

Main Results:

• dnSNARE-mediated gliotransmission was essential for LPS to increase sleep pressure.
• Blocking adenosine receptor 1 (A1R) with CPT mimicked the effect of impaired gliotransmission on LPS-induced sleep pressure.
• Data indicate that astrocyte-derived adenosine, acting via A1R, contributes to LPS-induced sleep modulation.

Conclusions:

• Astrocytes are critical mediators of immune-induced increases in sleep pressure.
• Astrocytic adenosine signaling through A1 receptors is a key pathway through which systemic LPS administration impacts sleep homeostasis.
• This study highlights a novel role for astrocytes in integrating immune signals to regulate sleep.