Abstract：
Parabens are widely used as antibacterial preservatives in foods and personal care products. The knowledge about the modes of toxic action of parabens on development and reproduction remain very limited. The present study attempted to establish a development and reproduction-associated adverse outcome pathway (AOP) by evaluating the effects of methylparaben (MP), ethylparaben (EP), propylparaben (PP) and butylparaben (BP) on the biosynthesis of gonadotropins, which are key hormones for development and reproduction. MP and BP significantly upregulated the mRNA and protein levels of follicle stimulating hormone (FSH) and luteinizing hormone (LH) in pituitary gonadotropic cells in a concentration-dependent manner. Activation of gonadotropin-releasing hormone receptor (GnRHR) was required for gonadotropin biosynthesis induced by BP, but not MP. Molecular docking data further demonstrated the higher binding efficiency of BP to human GnRHR than that of MP, suggesting GnRHR as a potential molecular initiative event (MIE) for BP-induced gonadotropin production. L-type voltage-gated calcium channels (VGCCs) were found to be another candidate for MIE in gonadotropic cells response to both MP and BP exposure. The calcium-dependent activation of extracellular signal-regulated kinase 1 (ERK1) and ERK2 was subsequently required for MP- and BP-induced activation of GnRHR and L-type VGCCs pathways. In summary, MP and BP promoted gonadotropin biosynthesis through their interactions with cellular macromolecules GnRHR, L-type VGCCs, and subsequent key event ERK1/2. This is the first study to report the direct interference of parabens with gonadotropin biosynthesis and establish a potential AOP based on pathway-specific mechanism, which contributes to the effective screening of environmental chemicals with developmental and reproductive health risks.
摘要：
对羟基苯甲酸酯广泛用作食品和个人护理产品中的抗菌防腐剂。关于对羟基苯甲酸酯对发育和繁殖的毒性作用方式的知识仍然非常有限。本研究试图通过评估对羟基苯甲酸甲酯（MP）的作用来建立发育和生殖相关的不良结局途径（AOP）。对羟基苯甲酸乙酯（EP），对羟基苯甲酸丙酯（PP）和对羟基苯甲酸丁酯（BP）对促性腺激素的生物合成，是发育和繁殖的关键激素。MP和BP以浓度依赖的方式显着上调垂体促性腺激素细胞中卵泡刺激素（FSH）和黄体生成素（LH）的mRNA和蛋白水平。促性腺激素释放激素受体（GnRHR）的激活是由BP诱导的促性腺激素生物合成所必需的，但不是MP。分子对接数据进一步证明BP与人GnRHR的结合效率高于MP,提示GnRHR是BP诱导的促性腺激素产生的潜在分子主动事件（MIE）。发现L型电压门控钙通道（VGCC）是促性腺激素细胞对MP和BP暴露的反应中MIE的另一个候选者。随后，MP和BP诱导的GnRHR和L型VGCCs途径激活需要钙依赖性激活细胞外信号调节激酶1（ERK1）和ERK2。总之,MP和BP通过与细胞大分子GnRHR的相互作用促进促性腺激素的生物合成，L型VGCC,和随后的关键事件ERK1/2。这是首次报道对羟基苯甲酸酯对促性腺激素生物合成的直接干扰，并建立了基于途径特异性机制的潜在AOP，这有助于有效筛选具有发育和生殖健康风险的环境化学品。
