Estrogen Receptor α (ERα) Mediates Stimulatory Effects of Estrogen on Aromatase (CYP19) Gene Expression in Human Placenta
Estrogen Receptor α (ERα) Mediates Stimulatory Effects of Estrogen on Aromatase (CYP19) Gene Expression in Human Placenta
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DOI：
10.1210/me.2008-0371
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发表时间：
2009-06-01
影响因子：
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通讯作者：
Mendelson, Carole R.
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文献类型：
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作者：
Kumar, Premlata;Kamat, Amrita;Mendelson, Carole R.
人类芳香化酶（hCYP19）基因的胎盘特异性外显子L1上游246 bp区域介导胎盘特异性、发育性和O-2表达调控。在本研究中，将细胞滋养细胞培养在含炭剥离血清或含雌激素受体拮抗剂ICI 182780的无酚红培养基中，可阻止滋养细胞分化和相关的CYP19表达诱导，提示雌激素/ER的刺激作用。内质网α蛋白在人滋养细胞中表达，并在合胞滋养细胞分化过程中增加，而内质网β蛋白未检测到。突变分析显示，在转染的COS-7细胞中，雌二醇/ER α对hCYP19L1启动子活性的诱导作用需要-208 bp的雌激素反应元件样序列（re - ls）。体外观察到与细胞滋养细胞核蛋白相比，合胞滋养细胞与ERE-LS的结合增加；然而，ER α抗体不能超移复合物，并且在体外转录/翻译的ER α不能结合。尽管如此，培养的滋养细胞的染色质免疫沉淀试验显示，在诱导hCYP19表达之前，内源性ER α募集到含有ERE-LS的-255至-155- bp区域；这被ICI 182780抑制。染色质免疫沉淀还显示，在滋养细胞分化过程中，与该区域相关的乙酰化组蛋白H3（K9/14）增加，甲基化组蛋白H3（K9）减少。当滋养细胞与ICI 182780孵育时，这些修饰被阻止，这表明ER α募集到-255至-155-bp区域促进组蛋白修饰，导致hCYP19转录增加。因此，在滋养细胞分化过程中，雌激素/ER α发挥正反馈作用，促进与hCYP19基因转录诱导相关的容许性组蛋白修饰。（分子内分泌学23:784-793,2009）
A 246-bp region upstream of placenta-specific exon L1 of the human aromatase (hCYP19) gene mediates placenta-specific, developmental, and O-2 regulation of expression. In this study, trophoblast differentiation and associated induction of CYP19 expression were prevented when cytotrophoblasts were cultured in phenol red-free medium containing charcoal-stripped serum or with the estrogen receptor (ER) antagonist, ICI 182,780, suggesting a stimulatory role of estrogen/ER. ER alpha protein was expressed in human trophoblasts and increased during syncytiotrophoblast differentiation, whereas ER beta was undetectable. Mutational analysis revealed that an estrogen response element-like sequence (ERE-LS) at -208 bp is required for inductive effects of estradiol/ER alpha on hCYP19L1 promoter activity in transfected COS-7 cells. Increased binding of syncytiotrophoblast compared with cytotrophoblast nuclear proteins to the ERE-LS was observed in vitro; however, ER alpha antibodies failed to supershift the complex and in vitro-transcribed/translated ER alpha did not bind. Nonetheless, chromatin immunoprecipitation assays in cultured trophoblasts revealed recruitment of endogenous ER alpha to the -255- to -155- bp region containing the ERE-LS before induction of hCYP19 expression; this was inhibited by ICI 182,780. Chromatin immunoprecipitation also revealed increased acetylated histone H3(K9/14) and decreased methylated histone H3(K9) associated with this region during trophoblast differentiation. These modifications were prevented when trophoblasts were incubated with ICI 182,780, suggesting that ER alpha recruitment to the -255- to -155-bp region promotes histone modifications leading to increased hCYP19 transcription. Thus, during trophoblast differentiation, estrogen/ER alpha exerts a positive feedback role, which promotes permissive histone modifications that are associated with induction of hCYP19 gene transcription. (Molecular Endocrinology 23: 784-793, 2009)