This 2022 human cell study investigated DNA methylation and aging:
“Models based on DNA methylation can be used to predict the age of biological samples, but their interpretability is limited due to the lack of causal inferences. Neither existing epigenetic clocks nor DNA methylation changes are enriched in causal CpG sites. Causal CpGs include similar numbers of sites that contribute to aging and protect against it, yet their combined contribution negatively affects age-related traits.
One general approach for developing anti-aging interventions is to identify molecular changes during aging and use these changes as targets to modulate the aging process. A similar idea has also been applied to evaluate potential longevity interventions. However, this logic is intrinsically flawed, as correlation does not imply causation, and age-related changes are not necessarily causal to age-associated declines.
We developed a framework for integrating causal knowledge into epigenetic clock models and constructed DamAge and AdaptAge that measure age-related damaging and adaptive changes, respectively. DamAge acceleration is associated with various adverse conditions (e.g., mortality risk), whereas AdaptAge acceleration is related to beneficial adaptations.
We found that transcription factor (TF)-binding sites of BRD4 and CREB1 are enriched with CpG sites whose methylation levels promote healthy longevity, and TF-binding sites for HDAC1 are enriched with CpG sites whose methylation levels decrease healthy longevity.
- BRD4 contributes to cell senescence and promotes inflammation, and higher DNA methylation at BRD4 binding sites may inhibit the downstream effects of BRD4 and promote healthy longevity.
- CREB1 is related to type II diabetes and neurodegeneration, and mediates the effect of calorie restriction. Our data suggest that higher methylation at CREB1-binding sites may support its longevity effects.
- HDAC1 is a histone deacetylase, and its activity increases with aging and may promote age-related phenotypes. Increased DNA methylation at HDAC1 binding sites may causally inhibit healthy longevity.
Our causality-informed clock models provide novel insights into the aging mechanisms and testing interventions that delay aging and reverse biological age.”
https://www.biorxiv.org/content/10.1101/2022.10.07.511382v1 “Causal Epigenetic Age Uncouples Damage and Adaptation”