Supraclavicular brown adipocytes originate fromTbx1⁺myoprogenitors

Brown adipose tissue (BAT) dissipates energy as heat, contributing to temperature control, energy expenditure, and systemic homeostasis. In adult humans, BAT mainly exists in supraclavicular areas and its prevalence is associated with cardiometabolic health. However, the developmental origin of supraclavicular BAT remains unknown. Here, using genetic fate mapping in mice, we demonstrate that supraclavicular brown adipocytes do not develop from thePax3⁺/Myf5⁺epaxial dermomyotome that gives rises to interscapular BAT. Instead, theTbx1⁺lineage that specifies the pharyngeal mesoderm marks the majority of supraclavicular brown adipocytes.Tbx1^Cre-mediated ablation of peroxisome proliferator-activated receptor gamma (PPARγ) or PR/SET Domain 16 (PRDM16), components of the transcriptional complex for brown fat determination, leads to supraclavicular BAT paucity or dysfunction, thus rendering mice more sensitive to cold exposure. Moreover, human deep neck BAT expresses higher levels of theTBX1gene than subcutaneous neck white adipocytes. Taken together, our observations reveal location-specific developmental origins of BAT depots and call attention toTbx1⁺lineage cells when investigating human relevant supraclavicular BAT.