HIRA-mediated H3.3 deposition preserves hepatocyte cell identity during non-proliferative liver aging [RNA-Seq 2]

Conversely, maintenance of chromatin integrity preserves cell identity and promotes healthy aging, albeit through different mechanisms in proliferating and non-proliferating cells. However, whether tissue regeneration with its associated cell proliferation can rescue defects in epigenetic maintenance in otherwise non-proliferative cells remains unclear.

The histone chaperone HIRA deposits the histone variant H3.3 in a DNA replication–independent manner, leading to its accumulation in aging, non-proliferating cells. Here, we show that hepatocyte-specific loss of HIRA causes loss of cell identity, metabolic dysfunction, and accelerated fibrotic pathology with age. Transcriptomic and epigenomic analyses indicate that HIRA–H3.3 preserves chromatin integrity and sustains transcription of highly expressed genes.