Laboratory of Gynecological Oncology and Reproductive Health, Department of Obstetrics and Gynaecology, Xiangyang No.1 People's Hospital, Hubei University of Medicine, Xiangyang, Hubei Province 441000, China; Hubei Key Laboratory of Embryonic Stem Cell Research, Hubei University of Medicine, Shiyan, Hubei Province 442000, China.
NHC Key Laboratory of Birth Defects and Reproductive Health, Chongqing Population and Family Planning Science and Technology Research Institute, Chongqing 400020, China.
Sci Total Environ. 2020 May 15;717:137280. doi: 10.1016/j.scitotenv.2020.137280. Epub 2020 Feb 12.
Triclosan (TCS) is a potent antibacterial and antifungal compound that is extensively used in various daily products. TCS is also considered as an underlying endocrine disruptor and has anti-androgenic effects. In our previous work, we found that TCS suppressed testicular steroidogenesis via the miR-6321/JNK/Nur77 cascade, but roles of the abnormal expression of miR-142-5p and P450c17 in this molecular event were still unknown. Therefore, to verify the hypothesis that miR-142-5p and P450c17 might significantly function in other manner in testosterone decline after TCS exposure, Sprague-Dawley rats and the rat Leydig cell line were used in this study. Results showed that after TCS exposure, testicular histomorphology was abnormally changed and testosterone level was declined. Overexpressed miR-142-5p by TCS directly targeted the JAK1/STAT1 pathway. Bidirectional Co-IP assays and the use of STAT1 activator demonstrated that STAT1 could interact with and regulate Sp1. The activity, mRNA level, and protein expression of DNMT1 and DNMT3β were all decreased after TCS treatment. Sp1 silencing, ChIP, and qPCR assays showed that Sp1 regulated DNMT1 expressions by directly binding to the promoter region of DNMT1. Though the DNA methylation status of the DAX1 promoter was not affected, TCS induced the transcription and translation of DAX1 by DNMT1, in turn leading to the inhibition of steroidogenic P450c17. Taken together, TCS-induced miR-142-5p inhibits P450c17 by the JAK1/STAT1 pathway and downstream Sp1/DNMT1/DAX1 cascade, finally facilitating the decrease in testosterone levels.
三氯生（TCS）是一种强效的抗菌和抗真菌化合物，广泛应用于各种日常产品中。TCS 也被认为是一种潜在的内分泌干扰物，具有抗雄激素作用。在我们之前的工作中，我们发现 TCS 通过 miR-6321/JNK/Nur77 级联抑制睾丸类固醇生成，但 miR-142-5p 和 P450c17 的异常表达在这一分子事件中的作用仍不清楚。因此，为了验证 miR-142-5p 和 P450c17 在 TCS 暴露后睾丸酮下降的分子事件中可能以其他方式显著发挥作用的假设，本研究使用了 Sprague-Dawley 大鼠和大鼠睾丸间质细胞瘤（Leydig 细胞）系。结果表明，TCS 暴露后，睾丸组织形态学发生异常改变，睾丸酮水平下降。TCS 过表达的 miR-142-5p 可直接靶向 JAK1/STAT1 通路。双向 Co-IP 测定和使用 STAT1 激活剂表明，STAT1 可以与 Sp1 相互作用并调节 Sp1。TCS 处理后，DNMT1 和 DNMT3β 的活性、mRNA 水平和蛋白表达均降低。Sp1 沉默、ChIP 和 qPCR 测定表明，Sp1 通过直接结合 DNMT1 启动子区域来调节 DNMT1 的表达。虽然 DAX1 启动子的 DNA 甲基化状态没有受到影响，但 TCS 通过 DNMT1 诱导 DAX1 的转录和翻译，进而抑制类固醇生成 P450c17。总之，TCS 诱导的 miR-142-5p 通过 JAK1/STAT1 通路和下游 Sp1/DNMT1/DAX1 级联抑制 P450c17，最终导致睾丸酮水平下降。
