FOXO and insulin signaling regulate sensitivity of the circadian clock to oxidative stress

Area of Science:

• Chronobiology
• Molecular Biology
• Metabolism

Background:

• Circadian rhythms are regulated by environmental and endogenous factors.
• Oxidative stress is an increasing concern in aging and disease.
• The role of FOXO in circadian clock regulation is not fully understood.

Purpose of the Study:

• To investigate the sensitivity of circadian clock function to oxidative stress.
• To determine the role of the foxo gene in mediating this sensitivity.
• To explore the link between metabolism, oxidative stress, aging, and circadian rhythms.

Main Methods:

• Utilized Drosophila melanogaster (fruit fly) models.
• Compared wild-type and foxo mutant flies under oxidative stress conditions.
• Assessed circadian clock gene cycling in peripheral tissues and behavioral rhythms.
• Employed transgenic approaches to modulate foxo expression in specific tissues.
• Investigated the impact of insulin signaling pathway components on clock function.

Main Results:

• Wild-type flies showed attenuated clock gene cycling under oxidative stress.
• foxo mutants exhibited loss of behavioral rhythms and impaired peripheral clock gene cycling.
• Transgenic foxo expression in the fat body rescued the mutant phenotype, indicating non-cell-autonomous effects.
• Overexpression of insulin receptor or Akt in the fat body exacerbated clock susceptibility to oxidative stress.
• foxo mutants displayed accelerated decline in rest:activity rhythms with age.

Conclusions:

• FOXO is essential for maintaining circadian clock function under oxidative stress.
• Metabolic pathways, particularly insulin signaling, influence central clock function.
• Oxidative stress contributes to age-associated degeneration of behavioral rhythms.
• FOXO plays a critical role in mitigating age-related circadian rhythm deterioration.