Short-term cold exposure induces persistent epigenomic memory in brown fat [ATAC-Seq]

Deficiency of the epigenome modulator histone deacetylase 3 (HDAC3) in brown adipose tissue (BAT) impairs the ability of mice to survive in near-freezing temperatures. Here, we report that short-term exposure to mild cold temperature (STEMCT: 15°C for 24 hours) averted lethal hypothermia of mice lacking HDAC3 in BAT (HDAC3 BAT KO) exposed to 4°C. STEMCT restored the induction of the thermogenic coactivator PGC-1a along with UCP1 at 22°C, which is greatly impaired in HDAC3-deficient BAT, and deletion of either UCP1 or PGC-1a prevented the protective effect of STEMCT. Remarkably, the protection of HDAC3 BAT KO mice from cold intolerance following STEMCT lasted for up to 7 days. Transcriptional activator C/EBPb was induced by short-term cold exposure in mouse and human BAT and, uniquely, remained high for 7 days following STEMCT. Furthermore, analysis of C/EBPb activity revealed increased binding following STEMCT at genes, including the enhancers/promotors of UCP1 and PGC-1a. These results reveal the existence of a cold-adaptive epigenomic memory mediated by C/EBPb that is persistent and HDAC3-independent.