Circadian and sleep/wake-dependent variations in tau phosphorylation are driven by temperature

Area of Science:

• Neuroscience
• Chronobiology
• Molecular Biology

Background:

• Hyperphosphorylated tau protein aggregates are key markers of Alzheimer's disease (AD).
• Sleep disturbances are prevalent in AD and may increase AD risk.
• Previous studies suggest sleep disruption affects tau phosphorylation in mice.

Purpose of the Study:

• To investigate the physiological regulation of tau phosphorylation during the sleep-wake cycle.
• To determine if tau phosphorylation is controlled by circadian rhythms.

Main Methods:

• Western blotting was used to analyze tau protein, kinases, and phosphatases in mouse brains.
• Body temperature was monitored in awake, sleeping, and sleep-deprived mice.
• Experiments were conducted on neuronal cells to validate findings.

Main Results:

• Tau phosphorylation exhibits circadian variations, increasing during sleep but not during sleep deprivation.
• These changes are linked to body temperature fluctuations; warmer temperatures prevented hyperphosphorylation.
• Inhibition of protein phosphatase 2A (PP2A) may contribute to tau hyperphosphorylation during sleep-induced hypothermia.

Conclusions:

• Tau phosphorylation is regulated by a circadian rhythm primarily influenced by body temperature and sleep.
• This research provides a physiological basis for understanding how sleep disruption impacts tau and AD pathology.
• Further research can explore the link between sleep, tau, and neurodegenerative diseases.