Ageing hallmarks exhibit organ-specific temporal signatures

In order to understand the cellular processes that underlie ageing, the authors performed plasma proteomics at 10 different ages across the lifespan of the mouse. They integrated these data with a parallel large study published alongside this paper in the same edition (1), which describes the 'Mouse Ageing Cell Atlas', a single-cell transcriptomic atlas that characterizes changes in gene expression with age across 23 tissues. Together, the data reveal clustered patterns of changes ('trajectory groups') in gene expression and protein levels, consistent with coherent biological functions, including extracellular matrix regulation, unfolded protein binding, mitochondrial function, circadian rhythm, and inflammatory and immune response.