Floro, A. | bioRxiv Science

bioRxiv2023

Chronically disrupted sleep induces senescence in the visceral adipose tissue of C57BL/6J mice

The role of sleep in systemic aging remains poorly understood, despite sleeps essential function in preserving overall health and the prevalence of reduced sleep quality in modern society. Although reduced sleep correlates with an elevated risk of age-related diseases in humans, the mechanisms underlying this are unclear. In this study, we established a link between sleep and aging by demonstrating that disrupting sleep in C57BL/6 mice drives cellular senescence in the visceral adipose tissue. Sleep disruption also led to increased oxidative stress and DNA damage, both recognized triggers for senescence induction. Cellular senescence is implicated in numerous age-related conditions which are associated with insufficient sleep, such as cardiovascular disease, type 2 diabetes, and chronic inflammation. Our findings identify an accumulation of senescent cells in the adipose tissue, which serves as a potential target through which disturbed sleep accelerates the aging process and elevates the risk of age-related diseases.

molecular biology↗

bioRxiv2023

Development of a novel epigenetic clock resistant to changes in immune cell composition

Epigenetic clocks are age predictors that use machine-learning models trained on DNA CpG methylation values to predict chronological or biological age. Increases in predicted epigenetic age relative to chronological age (epigenetic age acceleration) are connected to aging-associated pathologies, and changes in epigenetic age are linked to canonical aging hallmarks. However, epigenetic clocks rely on training data from bulk tissues whose cellular composition changes with age. We found that human naive CD8+ T cells, which decrease during aging, exhibit an epigenetic age 15-20 years younger than effector memory CD8+ T cells from the same individual. Importantly, homogenous naive T cells isolated from individuals of different ages show a progressive increase in epigenetic age, indicating that current epigenetic clocks measure two independent variables, aging and immune cell composition. To isolate the age-associated cell intrinsic changes, we created a new clock, the IntrinClock, that did not change among 10 immune cell types tested. IntrinClock showed a robust predicted epigenetic age increase in a model of replicative senescence in vitro and age reversal during OSKM-mediated reprogramming.

genomics↗