How does the body know how old it is? Introducing the epigenetic clock hypothesis

Area of Science:

• Gerontology
• Epigenetics
• Chronobiology

Background:

• Biological clocks regulate various life processes in animals and plants, including aging.
• Existing proposed aging clocks include the suprachiasmatic nucleus, hypothalamus, thymus involution, and cellular senescence.
• Cellular senescence, linked to telomere attrition, is a validated aging regulator.

Purpose of the Study:

• To explore the hypothesis that biological clocks influence the timing of senescence.
• To propose a novel epigenetic aging clock mechanism.

Main Methods:

• Review of evolutionary theories on aging.
• Analysis of age-related changes in gene expression and DNA methylation.
• Focus on stem cell methylation states as a potential aging clock.

Main Results:

• Gene expression and DNA methylation patterns change characteristically with age.
• A novel aging clock candidate based on epigenetics and chromosome methylation in stem cells is proposed.

Conclusions:

• The timing of senescence is likely influenced by biological clocks.
• Epigenetic modifications, specifically DNA methylation in stem cells, represent a promising candidate for a novel aging clock.
• Validation of this epigenetic clock could present new avenues for medical interventions targeting aging.