Gestational exposure to BDE-209 induces placental injury via the endoplasmic reticulum stress-mediated PERK/ATF(4)/CHOP signaling pathway

Several epidemiological studies have reported significant associations between prenatal polybrominated diphenyl ethers (PBDEs) exposure and adverse birth outcomes. Placental injury is thought to mediate these associations. However, few study has investigated the adverse effects of PBDEs exposure on placental growth and development. We examined the impacts of gestational exposure to BDE-209, the most abundant PBDE conger detected in human samples, on placental structure and function, and its model of action in vivo and in vitro. Pregnant mice were exposed to 0, 2, 20, 200 mg/kg/day of BDE-209 by gavages from gestational day (GD) 0 to GD18. Results showed that gestational BDE-209 exposure significantly reduced placental weight, impaired placental vascular development and induced placental cell apoptosis. In addition, gestational BDE-209 exposure impaired placental transport and endocrine function as demonstrated by markedly downregulated expression of Glut1, Znt1, Pgf and Igf2 in BDE-209-treated placentas. Mechanistically, gestational exposure to BDE-209 upregulated the expression of GRP78, and 3 downstream proteins (p-eIF2 alpha, ATF4 and CHOP) of the PERK signaling, suggesting the activation of endoplasmic reticulum (ER) stress and PERK signaling pathway in mouse placentas. Further in vitro study showed that PERK siRNA pretreatment markedly reversed BDE-209-induced cell apoptosis in human JEG-3 cells. Collectively, our results suggest that the activation of the ER stress-mediated PERK/ATF4/ CHOP signaling pathway played a role in BDE-209-induced placental injury. Our findings provide new insight into the mechanisms of BDE-209 induced reproductive and developmental toxicity.