biostudies-literatureZammit NWNIDDK NIH HHSeads0478https://www.ebi.ac.uk/biostudies/studies/S-EPMC12363373biostudies-literatureUnknown10(109)Whereas visceral adipose tissue (VAT) primarily stores excess energy, brown adipose tissue (BAT) dissipates it in a process termed nonshivering thermogenesis. Several key VAT features, particularly murine epidydimal VAT, are regulated by a distinct population of regulatory T (T_reg) cells, raising the question of whether BAT hosts an analogous population. Although T_reg cells have been observed in BAT, their properties and mechanisms of action require elucidation. We found BAT T_reg cells to be heterogeneous in subtissular localization and subtype composition. Punctual depletion of T_reg cells unleashed interferon-γ (IFN-γ)-producing lymphocytes in BAT, but not in subcutaneous or visceral fat depots, leading to IFN-γ-dependent mitochondrial dysfunctiScience immunologyRegulatory T cells in brown adipose tissue safeguard thermogenesis by restraining interferon-γ-producing lymphocytes.PMC12363373R01 DK092541Zammit NWSpiegelman BMMathis DBenoist CLangston PKWang GZhou YVargas-Castillo AfalseRegulatory T cells in brown adipose tissue safeguard thermogenesis by restraining interferon-γ-producing lymphocytes.Whereas visceral adipose tissue (VAT) primarily stores excess energy, brown adipose tissue (BAT) dissipates it in a process termed nonshivering thermogenesis. Several key VAT features, particularly murine epidydimal VAT, are regulated by a distinct population of regulatory T (T_reg) cells, raising the question of whether BAT hosts an analogous population. Although T_reg cells have been observed in BAT, their properties and mechanisms of action require elucidation. We found BAT T_reg cells to be heterogeneous in subtissular localization and subtype composition. Punctual depletion of T_reg cells unleashed interferon-γ (IFN-γ)-producing lymphocytes in BAT, but not in subcutaneous or visceral fat depots, leading to IFN-γ-dependent mitochondrial dysfuncti2025-01-01T00:00:00Z2025 Jul2026-05-02T03:49:53.813Z2026-04-07T17:36:15.144ZS-EPMC123633734071204610.1126/sciimmunol.ads0478