ETS-2 deficiency impairs brown adipose tissue function through Prdm16 repression.

BACKGROUND: Brown adipose tissue (BAT) and beige adipocytes regulate adaptive thermogenesis and systemic energy balance, whereas BAT dysfunction contributes to obesity and metabolic disease. Although ETS transcription factors participate in adipocyte biology, the role of ETS-2 in BAT remains unclear. METHODS: Adipocyte-specific Ets-2 knockout mice were generated using the Adipoq-Cre system. BAT morphology, thermogenic responses, energy expenditure, and mitochondrial structure and function were assessed under basal conditions, cold exposure, β3-adrenergic stimulation, and mTOR activation. Primary adipocytes were used for gain- and loss-of-function analyses. RNA-seq, CUT&Tag, luciferase reporter assays, Seahorse respirometry, rescue experiments, and public human adipose single-nucleus RNA-seq analyses were performed. RESULTS: ETS-2 was enriched in BAT and dynamically regulated during adipocyte differentiation. Adipocyte-specific Ets-2 deletion induced BAT whitening, reduced UCP-1 expression, impaired cold tolerance and β3-adrenergic responsiveness, and decreased oxygen consumption and energy expenditure. ETS-2 deficiency also disrupted mitochondrial ultrastructure and reduced respiratory capacity in brown adipocytes. Mechanistically, integrated RNA-seq and CUT&Tag identified Prdm16 as a direct ETS-2 target. ETS-2 loss repressed PRDM16, suppressed the PRDM16-PGC-1α-UCP-1 thermogenic program, and attenuated IRS-1-PI3K/Akt-mTOR signaling. PRDM16 overexpression and mTOR activation partially rescued ETS-2-deficient phenotypes. Human single-nucleus data further supported conservation of this regulatory axis. CONCLUSION: ETS-2 is a critical transcriptional regulator of BAT thermogenic function. By directly activating Prdm16 and maintaining both the PRDM16-PGC-1α-UCP-1 axis and IRS-1-PI3K/Akt-mTOR signaling, ETS-2 preserves mitochondrial integrity and adaptive thermogenesis. These findings identify the ETS-2-PRDM16 axis as a potential therapeutic target for metabolic diseases associated with BAT dysfunction.