Differential expression of two estrogen receptor β isoforms in the human fetal testis during the second trimester of pregnancy
Differential expression of two estrogen receptor β isoforms in the human fetal testis during the second trimester of pregnancy
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DOI：
10.1210/jc.2002-020811
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发表时间：
2003-01-01
影响因子：
5.8
通讯作者：
Saunders, PTK
中科院分区：
文献类型：
--
作者：
Gaskell, TL;Robinson, LLL;Saunders, PTK
睾丸癌在男性生殖道疾病患者中更为常见。有研究表明，胎儿时期不适当的雌激素暴露可能会影响睾丸生殖细胞的成熟，而睾丸生殖细胞是大多数睾丸癌的起源细胞。本研究的目的是确定人类胎儿生殖细胞（性腺细胞）是否是雌激素作用的潜在靶点。为了解决这个问题，我们使用RT-PCR和免疫组织化学方法检测了妊娠12-19周人类胎儿睾丸中雌激素受体（erα、erβ和erbet2变体）的表达模式。在所有胎儿睾丸中均未检测到erα、mRNA和蛋白。相反，使用针对ERbeta表达的铰链结构域的抗体在多个睾丸核中检测到。RT-PCR对全长野生型ERbeta （ERbeta1）或由备选的第8个外显子剪接形成的ERbeta2变体进行了特异性引物，对整个组织提取物和激光捕获回收的材料进行了RT-PCR，结果显示两种亚型的mrna都得到了表达。同型特异性单克隆抗体的免疫组织化学表明，与其他睾丸细胞类型相比，这些细胞表达的ERbeta2水平最高，而在性腺细胞中ERbeta1水平较低/检测不到。ERbeta1和ERbeta2均在部分（但不是全部）支持细胞、小管周围细胞和其他间质细胞（包括暂定为间质细胞的细胞）中检测到。我们的免疫组织化学结果表明，在妊娠中期，人类胎儿睾丸内的一些（但不是所有）体细胞表达野生型ERbeta （ERbeta1）蛋白和/或ERbeta （EMbeta2）的变体异构体，缺乏与雌二醇结合所必需的氨基酸。ERbeta2蛋白在胎儿性腺细胞中很容易检测到，而ERbeta1则没有。我们未检测到erα的表达。erbet2的表达，一种被认为是显性的变体；负受体，可能阻止雌激素在性腺细胞中的作用。我们认为，在胎儿生命的这一时期，雌激素配体最有可能作用于含有ERbeta1蛋白的体细胞。
Testicular cancer is more common in individuals with disorders of the male reproductive tract. It has been suggested that inappropriate exposure to estrogens during fetal life may have an impact on maturation of testicular germ cells that are the cells of origin of the majority of testis cancers. The aim of the present study was to establish whether human fetal germ cells (gonocytes) are a potential target of estrogen action. To address this issue, we used RT-PCR and immunohistochemistry to examine the pattern of expression of estrogen receptors (ERalpha, ERbeta, and ERbeta2 variant) in human fetal testes at 12-19 wk gestation. ERalpha, mRNA, and protein were not detected in any of the fetal testes. In contrast, using an antibody directed against the hinge domain of ERbeta expression was detected in multiple testicular nuclei. RT-PCR with primers specific for full-length wild-type ERbeta (ERbeta1) or the ERbeta2 variant formed by splicing of an alternative eighth exon, was performed on whole-tissue extracts and materials recovered by laser capture and revealed that mRNAs for both isoforms were expressed. Immunohistochemistry with isotype-specific monoclonal antibodies showed that ERbeta1 was low/undetectable in gonocytes, whereas these cells expressed the highest levels of ERbeta2, compared with other testicular cell types. Both ERbeta1 and ERbeta2 were detected in some but not all Sertoli cells, peritubular cells, and other interstitial cells including those tentatively identified as Leydig cells. Our immunohistochemical results demonstrate that during the second trimester, some but not all somatic cells within the human fetal testis express wild-type ERbeta (ERbeta1) protein and/or the variant isoform of ERbeta (EMbeta2) that lacks amino acids essential for binding of estradiol. ERbeta2 protein was readily detectable in fetal gonocytes, whereas ERbeta1 was not. We did not detect expression of ERalpha. The expression of ERbeta2, a variant proposed act as a dominant; negative receptor, might prevent estrogen action in gonocytes. We suggest that during this period of fetal life, estrogenic ligands are most likely to act on somatic cells that contain ERbeta1 protein.