Institute of Pharmacology, Polish Academy of Sciences, Department of Experimental Neuroendocrinology, 31-343 Krakow, Smetna Street 12, Poland.
Institute of Pharmacology, Polish Academy of Sciences, Department of Experimental Neuroendocrinology, 31-343 Krakow, Smetna Street 12, Poland.
J Steroid Biochem Mol Biol. 2018 Sep;182:106-118. doi: 10.1016/j.jsbmb.2018.04.016. Epub 2018 Apr 25.
Current evidence indicates that benzophenone-3 (BP-3) can pass through the placental and blood-brain barriers and thus can likely affect infant neurodevelopment. Despite widespread exposure, data showing the effects of BP-3 on the developing nervous system are scarce. This study revealed for the first time that prenatal exposure to BP-3 led to apoptosis and neurotoxicity, altered the levels of estrogen receptors (ERs) and changed the epigenetic status of mouse neurons. In the present study, subcutaneous injections of pregnant mice with BP-3 at 50 mg/kg, which is an environmentally relevant dose, evoked activation of caspase-3 and lactate dehydrogenase (LDH) release as well as substantial loss of mitochondrial membrane potential in neocortical cells of their embryonic offspring. Apoptosis-focused microarray analysis of neocortical cells revealed up-regulation of 22 genes involved in apoptotic cell death. This effect was supported by increased BAX and CASP3 mRNA and protein levels, as evidenced by qPCR, ELISAs and western blots. BP-3-induced apoptosis and neurotoxicity were accompanied by decreases in the mRNA and protein expression levels of ESR1 and ESR2 (also known as ERα and ERβ), with a simultaneous increase in GPER1 (also known as GPR30) expression. In addition to the demonstration that treatment of pregnant mice with BP-3 induced apoptosis, caused neurotoxicity and altered ERs expression levels in neocortical cells of their embryonic offspring, we showed that prenatal administration of BP-3 inhibited global DNA methylation as well as reduced DNMTs activity. BP-3 also caused specific hypomethylation of the genes Gper1 and Bax, an effect that was accompanied by increased mRNA and protein expression levels. In addition, BP-3 caused hypermethylation of the genes Esr1, Esr2 and Bcl2, which could explain the reduced mRNA and protein levels of the estrogen receptors. This study demonstrated for the first time that prenatal exposure to BP-3 caused severe neuronal apoptosis that was accompanied by impaired ESR1/ESR2 expression, enhanced GPER1 expression, global DNA hypomethylation and altered methylation statuses of apoptosis-related and ERs genes. We suggest that the effects of BP-3 in embryonic neurons may be the fetal basis of the adult onset of nervous system disease.
目前的证据表明，二苯甲酮-3（BP-3）可以穿过胎盘和血脑屏障，因此可能会影响婴儿的神经发育。尽管广泛接触，但有关 BP-3 对发育中神经系统影响的数据却很少。这项研究首次揭示，产前暴露于 BP-3 会导致细胞凋亡和神经毒性，改变雌激素受体（ERs）的水平，并改变小鼠神经元的表观遗传状态。在本研究中，以 50mg/kg 的剂量对怀孕的老鼠进行皮下注射 BP-3，这是一个与环境相关的剂量，会引发其胚胎后代新皮质细胞中 caspase-3 的激活和乳酸脱氢酶（LDH）的释放，以及线粒体膜电位的大量损失。对新皮质细胞进行的凋亡焦点微阵列分析显示，有 22 个与细胞凋亡有关的基因上调。这一效应得到了 qPCR、ELISA 和 Western blot 等方法检测到的 BAX 和 CASP3 mRNA 和蛋白水平升高的支持。BP-3 诱导的细胞凋亡和神经毒性伴随着 ESR1 和 ESR2（也称为 ERα 和 ERβ）的 mRNA 和蛋白表达水平降低，同时 GPER1（也称为 GPR30）的表达增加。除了证明用 BP-3 处理怀孕的老鼠会诱导凋亡、引起神经毒性并改变其胚胎后代新皮质细胞中的 ERs 表达水平外，我们还表明，产前给予 BP-3 会抑制全基因组 DNA 甲基化并降低 DNMTs 的活性。BP-3 还会导致 Gper1 和 Bax 基因的特异性低甲基化，这种效应伴随着 mRNA 和蛋白表达水平的升高。此外，BP-3 导致 Esr1、Esr2 和 Bcl2 基因的高甲基化，这可以解释雌激素受体 mRNA 和蛋白水平的降低。这项研究首次证明，产前暴露于 BP-3 会导致严重的神经元凋亡，伴随着 ERs 表达的受损、GPER1 表达的增强、全基因组 DNA 低甲基化以及与凋亡和 ERs 基因相关的甲基化状态的改变。我们认为，BP-3 在胚胎神经元中的作用可能是成人神经系统疾病发生的胎儿基础。
