Chimento A, Sirianni R, Zolea F, Bois C, Delalande C, Andò S, Maggiolini M, Aquila S, Carreau S, Pezzi V
Department of Pharmaco-Biology, University of Calabria, Arcavacata di Rende (CS), Italy.
Int J Androl. 2011 Oct;34(5 Pt 1):420-9. doi: 10.1111/j.1365-2605.2010.01100.x. Epub 2010 Sep 21.
Spermatogenesis is a precisely controlled and timed process, comprising mitotic divisions of spermatogonia, meiotic divisions of spermatocytes, maturation and differentiation of haploid spermatids giving rise to spermatozoa. It is well known that the maintenance of spermatogenesis is controlled by gonadotrophins and testosterone, the effects of which are modulated by a complex network of locally produced factors, including oestrogens. However, it remains uncertain whether oestrogens are able to activate rapid signalling pathways directly in male germ cells. Classically, oestrogens act by binding to oestrogen receptors (ESRs) 1 and 2. Recently, it has been demonstrated that rapid oestrogen action can also be mediated by the G-protein-coupled oestrogen receptor 1 (Gper). The aim of the present study was to investigate ESRs and Gper expression in primary cultures of adult rat round spermatids (RS) and define if oestradiol (E2) is able to activate, through these receptors, pathways involved in the regulation of genes controlling rat RS apoptosis and/or maturation. In this study, we demonstrated that rat RS express ESR1, ESR2 and Gper. Short-time treatment of RS with E2, the selective Gper agonist G1 and the selective ESR1 and ERβ agonists, 4,4',4"-(4-propyl-[1H]pyrazole-1,3,5-triyl) trisphenol (PPT) and 2,3-bis(4-hydroxyphenyl)-propionitrile (DPN), respectively, determined activation of Extra-cellular signal-regulated kinase (ERK1/2) through the involvement of epidermal growth factor receptor transactivation. In addition, we investigated the effects of ESRs and Gper pathway activation on factors involved in RS maturation. Expression of cyclin B1 mRNA was downregulated by E2, G1 and PPT, but not by DPN. A concomitant and inverse regulation of the pro-apoptotic factor Bax mRNA expression was observed in the same conditions, with DPN being the only one determining an increase in this factor expression. Collectively, these data demonstrate that E2 activates, through ESRs and Gper, pathways involved in the regulation of genes controlling rat RS apoptosis and differentiation such as cyclin B1 and Bax.
精子发生是一个精确控制且有时间限制的过程，包括精原细胞的有丝分裂、精母细胞的减数分裂、单倍体精子细胞的成熟和分化，最终产生精子。众所周知，精子发生的维持受促性腺激素和睾酮控制，其作用由包括雌激素在内的局部产生的因子组成的复杂网络调节。然而，雌激素是否能够直接在雄性生殖细胞中激活快速信号通路仍不确定。传统上，雌激素通过与雌激素受体（ESR）1和2结合发挥作用。最近，已证明快速雌激素作用也可由G蛋白偶联雌激素受体1（Gper）介导。本研究的目的是研究成年大鼠圆形精子细胞（RS）原代培养物中ESR和Gper的表达，并确定雌二醇（E2）是否能够通过这些受体激活参与调控控制大鼠RS凋亡和/或成熟的基因的信号通路。在本研究中，我们证明大鼠RS表达ESR1、ESR2和Gper。分别用E2、选择性Gper激动剂G1以及选择性ESR1和ERβ激动剂4,4',4"-(4-丙基-[1H]吡唑-1,3,5-三基)三苯酚（PPT）和2,3-双(4-羟基苯基)-丙腈（DPN）对RS进行短期处理，通过表皮生长因子受体反式激活作用确定细胞外信号调节激酶（ERK1/2）的激活。此外，我们研究了ESR和Gper信号通路激活对参与RS成熟的因子的影响。细胞周期蛋白B1 mRNA的表达被E2、G1和PPT下调，但未被DPN下调。在相同条件下观察到促凋亡因子Bax mRNA表达的伴随性和反向调节，DPN是唯一导致该因子表达增加的试剂。总的来说，这些数据表明E2通过ESR和Gper激活参与调控控制大鼠RS凋亡和分化的基因（如细胞周期蛋白B1和Bax）的信号通路。
