Formaldehyde crosslink exposure and genomic ageing

Ziel

DNA repair pathways are essential for human health and longevity. While their molecular mechanisms are well defined, their physiological roles across tissues remain less understood. Our foundational research identified a major source of endogenous DNA damage: reactive aldehydes such as acetaldehyde (from ethanol) and formaldehyde (from metabolism and diet), which generate toxic DNA crosslinks in the blood, brain, and kidney. To counter this, cells rely on a two-tier protection system. Tier 1 enzymes (ALDH2 and ADH5) detoxify aldehydes. Tier 2 repairs the damage aldehydes cause via the Fanconi anaemia (FA) pathway or transcription-coupled repair (TCR). Loss of either of these second-tier pathways leads to tissue-specific degeneration, as seen in FA, where blood is most affected, and Cockayne syndrome (CS), where kidney and brain degeneration dominate. In FORCE (Formaldehyde Crosslink Exposure in Genomic Ageing), we build on these discoveries to explore how non-haematopoietic tissues respond to crosslink damage. Using our novel SWITCH mouse models, where Tier 1 detoxification is restricted to blood, we bypass early lethality to reveal hidden vulnerabilities in other tissues. In SWITCH FA-deficient animals, the liver fails due to extreme hepatocyte polyploidy, yet – surprisingly - the rapidly renewing intestine remains unaffected. We will investigate the mechanisms behind hepatic failure and the unexpected resilience of enterocytes, aiming to identify new aldehyde-protective pathways. By contrast, in SWITCH TCR-deficient models, blood-borne formaldehyde detoxification protects against neurodegeneration and kidney failure. We will map the aldehyde-sensitive cell types and examine how systemic clearance preserves tissue function. Finally, we will screen for small molecules that reduce aldehyde toxicity, laying the foundation for new therapies against age-related decline driven by endogenous metabolic damage.