Neuroendocrinology Unit, GIGA Neurosciences, University of Liège, Liège, Belgium.
National Food Institute, Technical University of Denmark, Kgs. Lyngby, Denmark.
Front Endocrinol (Lausanne). 2023 Apr 3;14:1140886. doi: 10.3389/fendo.2023.1140886. eCollection 2023.
Estrogenic endocrine disrupting chemicals (EDCs) such as diethylstilbestrol (DES) are known to alter the timing of puberty onset and reproductive function in females. Accumulating evidence suggests that steroid synthesis inhibitors such as ketoconazole (KTZ) or phthalates may also affect female reproductive health, however their mode of action is poorly understood. Because hypothalamic activity is very sensitive to sex steroids, we aimed at determining whether and how EDCs with different mode of action can alter the hypothalamic transcriptome and GnRH release in female rats.
Female rats were exposed to KTZ or DES during perinatal (DES 3-6-12μg/kg.d; KTZ 3-6-12mg/kg.d), pubertal or adult periods (DES 3-12-48μg/kg.d; KTZ 3-12-48mg/kg.d).
Ex vivo study of GnRH pulsatility revealed that perinatal exposure to the highest doses of KTZ and DES delayed maturation of GnRH secretion before puberty, whereas pubertal or adult exposure had no effect on GnRH pulsatility. Hypothalamic transcriptome, studied by RNAsequencing in the preoptic area and in the mediobasal hypothalamus, was found to be very sensitive to perinatal exposure to all doses of KTZ before puberty with effects persisting until adulthood. Bioinformatic analysis with Ingenuity Pathway Analysis predicted "Creb signaling in Neurons" and "IGF-1 signaling" among the most downregulated pathways by all doses of KTZ and DES before puberty, and "PPARg" as a common upstream regulator driving gene expression changes. Deeper screening ofRNAseq datasets indicated that a high number of genes regulating the activity of the extrinsic GnRH pulse generator were consistently affected by all the doses of DES and KTZ before puberty. Several, including MKRN3, DNMT3 or Cbx7, showed similar alterations in expression at adulthood.
nRH secretion and the hypothalamic transcriptome are highly sensitive to perinatal exposure to both DES and KTZ. The identified pathways should be exploredfurther to identify biomarkers for future testing strategies for EDC identification and when enhancing the current standard information requirements in regulation.
已知雌激素内分泌干扰化学物质（EDCs）如己烯雌酚（DES）会改变女性青春期开始和生殖功能的时间。越来越多的证据表明，甾体合成抑制剂如酮康唑（KTZ）或邻苯二甲酸酯也可能影响女性生殖健康，但它们的作用方式尚不清楚。由于下丘脑的活动对性激素非常敏感，我们旨在确定具有不同作用方式的 EDC 是否以及如何改变雌性大鼠的下丘脑转录组和 GnRH 释放。
在围产期（DES 3-6-12μg/kg.d；KTZ 3-6-12mg/kg.d）、青春期或成年期（DES 3-12-48μg/kg.d；KTZ 3-12-48mg/kg.d）期间，雌性大鼠暴露于 KTZ 或 DES 中。
体外 GnRH 脉冲性研究表明，围产期暴露于最高剂量的 KTZ 和 DES 会延迟青春期前 GnRH 分泌的成熟，而青春期或成年期暴露则对 GnRH 脉冲性没有影响。通过 RNA 测序研究下丘脑转录组，在视前区和中脑基底部发现，围产期暴露于所有剂量的 KTZ 都会导致青春期前的下丘脑转录组非常敏感，并且这些影响一直持续到成年期。通过 Ingenuity Pathway Analysis 进行的生物信息学分析预测，围产期暴露于所有剂量的 KTZ 和 DES 之前，最下调的途径包括“神经元中的 Creb 信号传导”和“IGF-1 信号传导”，而“PPARg”则作为一个共同的上游调节因子驱动基因表达变化。对 RNAseq 数据集的更深入筛选表明，调节外源性 GnRH 脉冲发生器活性的大量基因始终受到围产期暴露于所有剂量的 DES 和 KTZ 的影响。其中一些，包括 MKRN3、DNMT3 或 Cbx7，在成年期的表达也显示出类似的改变。
GnRH 分泌和下丘脑转录组对 DES 和 KTZ 的围产期暴露非常敏感。应进一步研究所确定的途径，以确定 EDC 鉴定和增强当前监管标准信息要求的未来测试策略的生物标志物。
