Technical note: Isolation and characterization of ovine brown adipocyte precursor cells1,2

Brown adipose tissue (BAT) plays a critical role in regulating body temperature in newborn lambs. Availability of a stable BAT cell line would be invaluable for biochemical studies to elucidate cellular and molecular mechanisms responsible for nutritional regulation of fetal BAT growth and development. Ovine brown adipocyte precursor cells (BAPC) were isolated from fetal lambs at d 90 of gestation and cultured to establish a stable cell line. These cells were characterized by adipogenic differentiation and expression of a hallmark gene, uncoupling protein 1 (UCP1). The BAPC doubled every 24 h. After a 9-d induction with a serum-free Dulbecco's modified Eagle Ham/F12 medium, BAPC differentiated into brown adipocytes with large lipid droplets. The differentiation medium induced expression of UCP1 mRNA and protein in BAPC. Furthermore, after BAPC were passaged 30 times, they maintained similar cell morphology, the potential for adipogenic differentiation, and the ability to express UCP1. Taken together, we have established a stable ovine BAPC cell line for studying nutritional regulation of BAT growth and development in the fetus.