Epigenetics of Tcell aging

T cells are a heterogeneous population of cells that differ in their differentiation stages. Functional states are reflected in the epigenome that confers stability in cellular identity and is therefore important for naive as well as memory Tcell function. In many cellular systems, changes in chromatin structure due to alterations in histone expression, histone modifications and DNA methylation are characteristic of the aging process and cause or at least contribute to cellular dysfunction in senescence. Here, we review the epigenetic changes in Tcells that occur with age and discuss them in the context of canonical epigenetic marks in aging model systems as well as recent findings of chromatin accessibility changes in Tcell differentiation. Remarkably, transcription factor networks driving Tcell differentiation account for many of the age-associated modifications in chromatin structures suggesting that loss of quiescence and activation of differentiation pathways are major components of Tcell aging.