Qin Xiangfeng, Xiao Yaqian, Ye Cheng, Jia Jingyi, Liu Xiangjiang, Liang Hongwei, Zou Guiwei, Hu Guangfu
College of Fisheries, Huazhong Agricultural University, Wuhan, China.
Key Laboratory of Freshwater Biodiversity Conservation Ministry of Agriculture, Yangtze River Fisheries Research Institute, The Chinese Academy of Fishery Sciences, Wuhan, China.
Front Endocrinol (Lausanne). 2018 Jun 8;9:308. doi: 10.3389/fendo.2018.00308. eCollection 2018.
17β-estradiol (E2) is an important sex steroid produced by ovary and brain. In mammals, E2 plays an important role in hypothalamus-pituitary-gonad axis to regulate puberty onset, however, little is known about the functional role of E2 in teleost pituitary. Using prepubertal grass carp as model, three nuclear estrogen receptors (nERs: estrogen receptor alpha, estrogen receptor beta 1, and estrogen receptor beta 2) and two G protein-coupled estrogen receptors (GPER1: GPER1a and GPER1b) were isolated from grass carp pituitary. Tissue distribution analysis indicated that both nERs and GPERs were highly detected in grass carp pituitary, which suggested that E2 should play an important role in grass carp pituitary. Using primary cultured grass carp pituitary cells as model, high-throughput RNA-seq was used to examine the E2-induced differentially expressed genes (DEGs). Transcriptomic analysis showed that E2 could significantly upregulate the expression of 28 genes in grass carp pituitary cells, which were characterized into different functions including reproduction, gonad development, and central nervous system development. Further studies confirmed that E2 could induce luteinizing hormone (LH) and follicle-stimulating hormone (FSH) secretion and mRNA expression in prepubertal grass carp pituitary and . In the pituitary, LH and FSH regulation by E2 were mediated by both ERβ and GPER1. Apparently, E2-induced LHβ and FSHβ mRNA expression were mediated by adenylyl cyclase/cAMP/protein kinase A, phospholipase C/inositol 1,4,5-triphosphate/protein kinase C, and Ca/calmodulin/CaM-dependent protein kinase II pathways. In addition to LH and FSH, E2 could also induce growth regulation by estrogen in breast cancer 1 (a novel regulator for pituitary development) mRNA expression in grass carp pituitary cells. These results, as a whole, suggested that E2 could play an important role in gonadotropin hormone release and pituitary development in prepubertal grass carp.
17β-雌二醇（E2）是一种由卵巢和大脑产生的重要性类固醇。在哺乳动物中，E2在下丘脑-垂体-性腺轴中发挥重要作用，以调节青春期的开始，然而，关于E2在硬骨鱼垂体中的功能作用知之甚少。以青春期前草鱼为模型，从草鱼垂体中分离出三种核雌激素受体（nERs：雌激素受体α、雌激素受体β1和雌激素受体β2）和两种G蛋白偶联雌激素受体（GPER1：GPER1a和GPER1b）。组织分布分析表明，nERs和GPERs在草鱼垂体中均有高表达，这表明E2在草鱼垂体中应发挥重要作用。以原代培养的草鱼垂体细胞为模型，利用高通量RNA测序来检测E2诱导的差异表达基因（DEGs）。转录组分析表明，E2能显著上调草鱼垂体细胞中28个基因的表达，这些基因具有不同的功能，包括生殖、性腺发育和中枢神经系统发育。进一步的研究证实，E2能诱导青春期前草鱼垂体中促黄体生成素（LH）和促卵泡生成素（FSH）的分泌及mRNA表达。在垂体中，E2对LH和FSH的调节由ERβ和GPER1介导。显然，E2诱导的LHβ和FSHβ mRNA表达由腺苷酸环化酶/cAMP/蛋白激酶A、磷脂酶C/肌醇1,4,5-三磷酸/蛋白激酶C和Ca/钙调蛋白/CaM依赖性蛋白激酶II途径介导。除了LH和FSH外，E2还能诱导草鱼垂体细胞中雌激素调节的生长相关蛋白1（一种垂体发育的新型调节因子）mRNA的表达。总体而言，这些结果表明E2在青春期前草鱼的促性腺激素释放和垂体发育中可能发挥重要作用。
