Hypoxia regulates the expression of fatty acid-binding proteins in primary term human trophoblasts

Objective: Fatty acids (FAs) are essential for fetal development. Cellular FA uptake is modulated by fatty acid-binding proteins (FABPs). We hypothesized that hypoxia regulates the expression of FABPs in human trophoblasts. Study Design: Primary term human trophoblasts were cultured for 72 hours in either standard (O₂ = 20%) or hypoxic (O₂ < 1%) conditions. FABP expression was interrogated using polymerase chain reaction and Western immunoblotting. Trophoblast lipid droplets were examined using dipyrromethene boron difluoride 493/503 staining. Results: We detected the expression of FABP1, -3, -4, -5, and pm but not FABP2 or FABP6-9 subtypes in trophoblasts. Exposure to hypoxia markedly increased lipid droplet accumulation in trophoblasts. Consistent with this observation, hypoxia enhanced the expression of FABP1, -3, and -4. Lastly, agonists of peroxisome proliferator-activated receptor-γ enhanced the expression of FABP1 and -4 in trophoblasts. Conclusion: Hypoxia enhances the expression of FABP1, -3, and -4 in term human trophoblasts, suggesting that FABPs support fat accumulation in the hypoxic placenta.