Department of Environmental Chemistry, IDAEA-CSIC, Jordi Girona, Barcelona, Spain.
Department of Cellular Biology, Physiology and Immunology, Universitat de Barcelona (UB), Barcelona, Spain.
PLoS One. 2019 Feb 21;14(2):e0212577. doi: 10.1371/journal.pone.0212577. eCollection 2019.
Fluoxetine (FLX) is a pharmaceutical used to treat affective disorders in humans, but as environmental contaminant also affects inadvertently exposed fish in urban watersheds. In humans and fish, acute FLX treatment and exposure are linked to endocrine disruption, including effects on the reproductive and stress axes. Using the zebrafish model, we build on the recent finding that developmental FLX exposure reduced cortisol production across generations, to determine possible parental and/or life-stage-dependent (age and/or breeding experience) contributions to this phenotype. Specifically, we combined control and developmentally FLX-exposed animals of both sexes (F0) into four distinct breeding groups mated at 5 and 9 months, and measured offspring (F1) basal cortisol at 12 dpf. Basal cortisol was lower in F1 descended from developmentally FLX-exposed F0 females bred at 5, but not 9 months, revealing a maternal, life-stage dependent effect. To investigate potential molecular contributions to this phenotype, we profiled maternally deposited transcripts involved in endocrine stress axis development and regulation, epigenetic (de novo DNA methyltransferases) and post-transcriptional (miRNA pathway components and specific miRNAs) regulation of gene expression in unfertilized eggs. Maternal FLX exposure resulted in decreased transcript abundance of glucocorticoid receptor, dnmt3 paralogues and miRNA pathway components in eggs collected at 5 months, and increased transcript abundance of miRNA pathway components at 9 months. Specific miRNAs predicted to target stress axis transcripts decreased (miR-740) or increased (miR-26, miR-30d, miR-92a, miR-103) in eggs collected from FLX females at 5 months. Increased abundance of miRNA-30d and miRNA-92a persisted in eggs collected from FLX females at 9 months. Clustering and principal component analyses of egg transcript profiles separated eggs collected from FLX-females at 5 months from other groups, suggesting that oocyte molecular signatures, and miRNAs in particular, may serve as predictive tools for the offspring phenotype of reduced basal cortisol in response to maternal FLX exposure.
氟西汀（FLX）是一种用于治疗人类情感障碍的药物，但作为环境污染物，也会影响城市流域中无意中暴露的鱼类。在人类和鱼类中，急性 FLX 处理和暴露与内分泌干扰有关，包括对生殖和应激轴的影响。利用斑马鱼模型，我们在最近的研究结果的基础上，即发育性 FLX 暴露会降低几代人的皮质醇产生，来确定这种表型可能与父母或生命阶段（年龄和/或繁殖经验）有关。具体来说，我们将来自两性的对照和发育性 FLX 暴露的 F0 动物（雄性和雌性）结合到四个不同的繁殖组中，在 5 个月和 9 个月时进行交配，并在 12 dpf 时测量后代（F1）的基础皮质醇。来自发育性 FLX 暴露的 F0 雌性在 5 个月而不是 9 个月时繁殖的 F1 后代的基础皮质醇较低，这揭示了母体、生命阶段依赖的影响。为了研究这种表型的潜在分子贡献，我们对参与内分泌应激轴发育和调节的母体沉积转录物、表观遗传（从头 DNA 甲基转移酶）和转录后（miRNA 途径成分和特定 miRNA）基因表达的调节进行了分析。在 5 个月时收集的卵子中，母体 FLX 暴露导致糖皮质激素受体、dnmt3 同源物和 miRNA 途径成分的转录物丰度降低，而在 9 个月时，miRNA 途径成分的转录物丰度增加。在 5 个月时从 FLX 雌性收集的卵子中，预测靶向应激轴转录物的特定 miRNA 减少（miR-740）或增加（miR-26、miR-30d、miR-92a、miR-103）。在 9 个月时从 FLX 雌性收集的卵子中，miR-30d 和 miR-92a 的丰度增加仍然存在。对卵子转录物谱的聚类和主成分分析将 5 个月时从 FLX 雌性收集的卵子与其他组分开，这表明卵母细胞分子特征，特别是 miRNA，可能作为母体 FLX 暴露导致后代基础皮质醇降低的预测工具。
