The metabolic importance of brown adipose tissue (BAT) has been recognized, but its origins, particularly supraclavicular BAT (scBAT), remain unclear. Here, we traced scBAT to Mef2c-anterior heart field (AHF)-marked cells. Mef2c-AHF-marked cells isolated from scBAT can spontaneously differentiate into brown adipocytes, express mesenchymal stem cell markers, and can be isolated from the stromal-vascular fraction (SVF) of wild-type scBAT as [CD31−CD45−Sca-1+CD29+CD34−CD24−] (CD34−) cells. Mef2c-AHF-marked cells substantially overlap with Prrx1-marked cells in scBAT, which also contribute to beige adipocytes in inguinal white adipose tissue (iWAT). Similarly, CD34− cells isolated from the SVF of iWAT can spontaneously differentiate into beige adipocytes in vitro. Intersectional lineage tracing shows that common progenitors of Mef2c-AHF- and Prrx1-marked cells in scBAT emerge from the developing heart. Thus, these studies reveal a common origin for scBAT and cardiac tissue and suggest that scBAT and iWAT beige adipocytes arise from progenitor populations with overlapping lineage origins and molecular characteristics.
