Insulin and fatty acids regulate the expression of the fat droplet-associated protein adipophilin in primary human trophoblasts

Objective This study was undertaken to test the hypothesis that insulin and fatty acids regulate adipophilin expression in cultured human trophoblasts. Study design Cytotrophoblasts isolated from term human placentas were cultured in the absence or presence of insulin (10 nmol/L), and a mix of oleic and linoleic acid in serum-free medium. The expression of adipophilin as well as the fatty acid transport proteins (FATP) 2, 3, 4 and 6 was examined. Fat accumulation was quantified by BODIPY staining and fat uptake determined using [3H]-oleic acid. Results A combination of insulin and fatty acids enhanced the expression of adipophilin (2.3-fold, P< .05). In contrast, the expression of FATPs was unchanged. Furthermore, insulin and fatty acids increased the accumulation of fat droplets in trophoblasts by 4- to 5-fold (P< .05), but had no effect on oleic acid uptake. Conclusion Insulin and fatty acids enhance the expression of adipophilin and the formation of fatty acid droplets in term human trophoblasts.