Acute Circadian Disruption Due to Constant Light Promotes Caspase 1 Activation in the Mouse Hippocampus

Area of Science:

• Neuroscience
• Chronobiology
• Immunology

Background:

• Mammalian circadian systems regulate physiology, entrained by environmental cues like light.
• Circadian disruption from artificial light at night (ALAN) is linked to diseases.
• Altered circadian rhythms and immune dysregulation, including inflammasome activation, are seen in neurodegenerative diseases.

Purpose of the Study:

• To investigate the effect of constant light (LL) exposure on inflammasome activation in the mouse hippocampus.
• To understand the direct impact of circadian disruption on brain inflammasome activity.

Main Methods:

• Mice were exposed to constant light (LL) conditions.
• Circadian power, locomotor activity, and inflammasome activation markers (cleaved caspase-1, pro-interleukins) were analyzed in the hippocampus.

Main Results:

• Constant light exposure reduced circadian power and locomotor activity in mice.
• Cleaved caspase-1 levels were significantly elevated in the hippocampus of LL-exposed mice.
• No hallmarks of inflammasome priming or pro-interleukin cleavage were detected.

Conclusions:

• Acute circadian disruption via constant light leads to inflammasome assembly in the mouse hippocampus.
• This suggests that circadian disruption primes the brain, potentially increasing vulnerability to other stressors.