Estrogen receptor-β messenger ribonucleic acid ontogeny in the prostate of normal and neonatally estrogenized rats
Estrogen receptor-β messenger ribonucleic acid ontogeny in the prostate of normal and neonatally estrogenized rats
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DOI：
10.1210/en.139.3.874
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发表时间：
1998-03-01
期刊：
影响因子：
4.8
通讯作者：
Birch, L
中科院分区：
文献类型：
--
作者：
Prins, GS;Marmer, M;Birch, L
新生儿接触雌激素会永久改变大鼠前列腺生长和上皮分化，导致衰老时前列腺发育不良。这些影响是脑叶特异性的，在腹叶中观察到的反应最大。最近，从大鼠前列腺中克隆了一种新型雌激素受体（ER）互补DNA，由于其与经典ERα高度同源性，被命名为ER-β（ERβ）。该蛋白对 17β-雌二醇具有高亲和力，表明 ERβ 是介导雌激素作用的替代分子。重要的是，ER β 信使 RNA (mRNA) 定位于大鼠前列腺上皮细胞，这与大鼠前列腺中 ER α 的基质定位形成对比。本研究旨在确定大鼠前列腺叶中 ER β mRNA 表达的个体发育，并检查早期雌激素暴露对前列腺 ER β 表达的影响。雄性幼鼠在第1、3、5天给予25μg雌二醇或油；在第 1 天、第 3 天（仅限油）、第 6 天、第 10 天、第 30 天或第 90 天被杀死；前列腺叶被冷冻。使用S-36标记的反义mRNA探针处理纵向切片以进行原位杂交，该探针对应于大鼠ERβ互补DNA的5'非翻译区中的400bp EcoRI-AccI片段。使用图像分析来定量银颗粒。此外，从腹侧前列腺 (VP) 中分离出总 RNA，并用于半定量 RT-PCR。原位杂交结果显示，在用油处理的大鼠出生时，ERβ在间充质细胞和上皮细胞中均以低水平表达。从第 1 天起，所有基质细胞中的表达缓慢而显着下降，因此在对照成人前列腺中，基质 ER β mRNA 略高于背景。在油处理的对照大鼠中，随着细胞开始分化和导管腔化，VP 中的上皮 ERP mRNA 在第 6-10 天以及背叶和侧叶中的第 10-15 天增加到中等水平。第 30 天观察到 ER β 信息进一步显着增加，这表明完整的上皮 ER β 表达可能需要完成功能分化。到第 90 天，各叶之间的表达水平达到最大且相似。 RT-PCR 证实了第 1-90 天之间 ER β 的发育增加。通过原位杂交和 RT-PCR 测定，新生儿接触雌激素不会对前列腺 ER β mRNA 水平产生直接影响。然而，在第30天时在对照VP中观察到的上皮细胞表达的显着增加在新生期暴露于雌激素的动物的VP中受到抑制。到第 90 天，与油对照中的高表达相比，雌激素化大鼠的 VP 具有较低的 ER beta 信息水平。相比之下，新生雌激素化大鼠的背叶和侧叶在第 90 天时具有高水平的 ER β mRNA，与对照组相当。目前的数据表明，大鼠前列腺中的 ER β mRNA 表达受到发育调节，并且新生儿雌激素可以影响成年 VP 中的这种表达。由于新生儿雌激素的作用不是立竿见影的，因此数据表明早期雌激素暴露可能不会直接自动调节 ER β 表达，并表明成人对 ER β mRNA 表达的影响可能是间接的。不同叶中 ER β mRNA 印记的差异可能解释或反映了先前在大鼠前列腺中观察到的叶特异性新生儿雌激素印记。
Neonatal exposure to estrogens permanently alters rat prostate growth and epithelial differentiation leading to prostatic dysplasia on aging. The effects are lobe-specific, with the greatest response observed in the ventral lobe. Recently, a novel estrogen receptor (ER) complementary DNA was cloned from the rat prostate and termed ER-beta (ER beta) due to its high homology with the classical ER alpha. The protein possesses high affinity for 17 beta-estradiol, indicating that ER beta is an alternate molecule for mediating estrogenic effects. Importantly, ER beta messenger RNA (mRNA) was localized to rat prostatic epithelial cells, which contrasts with the stromal localization of ER alpha in the rat prostate. The present study was undertaken to determine the ontogeny of ER beta mRNA expression in the rat prostate lobes and to examine the effects of early estrogen exposure on prostatic ER beta expression. Male rat pups were given 25 mu g estradiol or oil on days 1, 3, and 5; were killed on day 1, 3 (oils only), 6, 10, 30, or 90; and prostate lobes were frozen. Longitudinal sections were processed for in situ hybridization using an S-36-labeled antisense mRNA probe corresponding to a 400-bp EcoRI-AccI fragment in the 5'untranslated region of rat ER beta complementary DNA. Image analysis was used to quantitate silver grains. In addition, total RNA was isolated from the ventral prostate (VP) and used for semiquantitative RT-PCR. Results from in situ hybridization revealed that at birth, ER beta was equivalently expressed at low levels in both mesenchymal and epithelial cells in oil-treated rats. From day 1 onwards, expression in all stromal cells slowly and significantly declined, so that in the control adult prostate, stromal ER beta mRNA was slightly above background. In the oil-treated control rats, epithelial ERP mRNA increased to moderate levels between days 6-10 in the VP and days 10-15 in the dorsal and lateral lobes as cells began differentiation and ducts lumenized. A further significant increase in ER beta message was observed at day 30, which indicates that full epithelial ER beta expression may require the completion of functional differentiation. By day 90, expression levels were maximal and similar between the lobes. RT-PCR substantiated this developmental increase in ER beta between days 1-90. Neonatal exposure to estrogens did not have an immediate effect on prostatic ER beta mRNA levels as determined by in situ hybridization and RT-PCR. However, the marked increase in epithelial cell expression at day 30 observed in the control VP was dampened in the VP of animals exposed neonatally to estrogens. By day 90, the VP of estrogenized rats possessed low ER beta message levels compared with the high expression in oil controls. In contrast, the dorsal and lateral lobes of neonatally estrogenized rats possessed high levels of ER beta mRNA at day 90, equivalent to controls. The present data demonstrate that ER beta mRNA expression in the rat prostate is developmentally regulated, and that neonatal estrogen can affect this expression in the adult VP. Because the effect of neonatal estrogens was not immediate, the data imply that early estrogen exposure may not directly autoregulate ER beta expression, and suggests that the adult effects on ER beta mRNA expression may be indirect. The differences in ER beta mRNA imprinting in the separate lobes may account for or reflect the lobe-specific neonatal estrogen imprints previously observed in the rat prostate.