A new progeroid syndrome reveals that genotoxic stress suppresses the somatotroph axis

Area of Science:

• Genetics
• Molecular Biology
• Aging Research

Background:

• XPF-ERCC1 endonuclease is crucial for repairing DNA lesions and interstrand crosslinks.
• XPF gene mutations can cause xeroderma pigmentosum, a cancer predisposition syndrome.
• Severe XPF mutations lead to progeroid symptoms, but the link between DNA damage and aging is unclear.

Purpose of the Study:

• To investigate the relationship between unrepaired DNA damage and accelerated aging.
• To explore the metabolic and molecular changes associated with DNA damage-induced progeroid symptoms.
• To understand the relevance of DNA damage to natural aging processes.

Main Methods:

• Comparative transcriptome analysis of old mice and a mouse model with a severe XPF mutation.
• Examination of gene expression patterns related to cell death, antioxidant defenses, and growth signaling.
• Correlation analysis between liver gene expression and aging phenotypes.

Main Results:

• A significant correlation was found between the liver transcriptome of old mice and the progeroid mouse model.
• XPF-ERCC1-deficient mice exhibited increased cell death, enhanced antioxidant defenses, and reduced IGF1 signaling.
• Similar molecular changes were observed in wild-type mice subjected to genotoxic stress, caloric restriction, or natural aging.

Conclusions:

• Unrepaired cytotoxic DNA damage induces a conserved metabolic response, mediated by the IGF1/insulin pathway.
• This response shifts resources from growth to somatic preservation, potentially extending lifespan.
• DNA damage causally contributes to aging, with stochastic damage and genetics determining decline rates.