SIRT6 overexpression counteracts chromatin aging in the male murine liver

Aging is associated with detrimental changes in chromatin structure and gene expression, contributing to inflammation, metabolic decline and tissue dysfunction. SIRT6, a histone deacetylase, plays a key role in maintaining chromatin integrity and promoting longevity. Our multi-omics approach, combining ATAC-seq, methylome and RNA-seq shows that aging leads to increased chromatin accessibility in the male murine liver, accompanied by upregulation of inflammation and downregulation of metabolic pathways. Remarkably, SIRT6 overexpression reverses these changes in chromatin structure, reducing inflammation and enhancing metabolic function. Notably, ETS family members and liver-enriched transcription factors are enriched in regions with increased and reduced accessibility during aging, respectively. ChIP-seq shows that H3K9ac, but not H3K56ac, is associated with increased accessibility during aging, and that SIRT6 can reverse this effect. Furthermore, AAV-mediated SIRT6 overexpression in aged male mice demonstrates that SIRT6 not only slows age-related chromatin changes but can also reverse them, rejuvenating chromatin accessibility to a youthful state.