Atlas maps how aging reshapes cells ^{CEFR B2}

Researchers at Rockefeller University published the most comprehensive atlas yet of how aging reshapes cells across the mammalian body. The team profiled nearly 7 million individual cells from 21 organs in 32 mice sampled at one month, five months and 21 months of age. Junyue Cao led the project and graduate student Ziyu Lu carried out much of the work; together they optimized single-cell ATAC-seq to measure DNA accessibility in single cells.

The atlas identifies more than 1,800 cell subtypes, including many rare types not described before, and it tracks how each subtype's abundance changes from young adulthood to middle age and old age. About a quarter of cell types showed significant population shifts: some muscle and kidney cells fell sharply, while various immune cells expanded. Many of these changes began by five months, suggesting that aging can be a continuation of developmental programs rather than only a late-life event.

Age-related changes were often synchronized across organs, with the same cellular states rising or falling in parallel. This pattern implies coordinating signals such as circulating factors in the blood. The study also found strong sex differences: about 40% of aging-associated changes differed between males and females, and females showed broader immune activation, which Cao links to higher autoimmune prevalence in women.

At the genomic level the researchers examined 1.3 million regions and observed about 300,000 with age-related shifts in accessibility. Roughly 1,000 of these changes occurred across many cell types and were associated with immune function, inflammation or stem cell maintenance. By comparing to prior work, the team found that cytokines can trigger many of the same changes; Cao hypothesizes that drugs that modulate cytokines might slow coordinated aging. The full atlas is available at epiage.net.