Daily changes in mouse brain proteins: Removing the Bmal1 clock gene increases support cell proteins and numbers in thinking and memory areas

Approximately 2700 proteins were identified in the mouse cerebral cortex and hippocampus.

• Fifteen proteins in the neocortex were found to be expressed differently between day and night, primarily related to mitochondrial function and neuronal plasticity.
• Only three proteins in the hippocampus showed significant diurnal expression changes, indicating less variability in this region compared to the neocortex.
• A reduction in the number of differentially expressed proteins was observed in mice lacking the clock gene Bmal1, suggesting local circadian clocks drive these daily rhythms.
• In the Bmal1 knockout cerebral cortex, proteins associated with astrocytes were notably upregulated, including GFAP and FABP7.
• An increased number of GFAP-positive astrocyte cells was identified in the Bmal1 knockout cerebral cortex.
• BMAL1 was confirmed to be present in astrocytes expressing GFAP and FABP7 in control mice.

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