BMAL1 rescued the hippocampus-dependent recognition memory induced by sleep deprivation

Area of Science:

• Neuroscience
• Chronobiology
• Molecular Biology

Background:

• Sleep is crucial for memory consolidation.
• The circadian clock gene BMAL1 regulates sleep-wake cycles and influences cognitive functions.
• Sleep deprivation is known to impair hippocampus-dependent memory.

Purpose of the Study:

• To investigate the role of BMAL1 in sleep deprivation-induced memory impairment.
• To explore the effects of sleep deprivation on circadian clock genes and related pathways in the hippocampus.
• To determine if compensating for BMAL1 can reverse memory deficits.

Main Methods:

• Mice were subjected to 4 weeks of sleep deprivation.
• Novel object recognition task was used to assess memory.
• Western blot, Real-time qPCR, and immunofluorescence were employed to detect gene and protein expression levels of circadian clock genes (PER1, PER2, CLOCK, BMAL1), Nrf2, and the PKA/CREB/BDNF pathway.

Main Results:

• Sleep deprivation significantly decreased novel object recognition memory.
• Expression of core clock genes (PER1, PER2, CLOCK, BMAL1) and the PKA/CREB/BDNF pathway were reduced in the hippocampus.
• Nrf2-mediated antioxidant capacity was compromised following sleep deprivation.
• Overexpression of BMAL1 in the suprachiasmatic nucleus (SCN) mitigated these negative effects.

Conclusions:

• Sleep deprivation impairs hippocampus-dependent recognition memory by reducing BMAL1 expression, disrupting the antioxidant system, and down-regulating the PKA/CREB/BDNF pathway.
• BMAL1 compensation in the SCN can reverse these deficits, suggesting a crucial role for the central circadian clock in maintaining hippocampal memory function.