Gao J, Mazella J, Tang M, Tseng L
Department of Obstetrics/Gynecology and Reproductive Medicine, School of Medicine, State University of New York at Stony Brook, 11794, USA.
Mol Endocrinol. 2000 Dec;14(12):1954-61. doi: 10.1210/mend.14.12.0564.
In human endometrium, the levels of progesterone receptor (PR) isoforms hPR-A and hPR-B are differentially regulated during the reproductive cycle. Progesterone significantly increases the content of hPR-A, the predominant isoform in decidualized stromal cells (1). The purpose of this study was to determine the capacity of hPR-A and hPR-B to transactivate the progestin-dependent target gene in human endometrial stromal cells. We examined the effect of cotransfection of hPR-A or hPR-B on the expression of the human insulin-like growth factor binding protein-1 (IGFBP-1) in endometrial stromal cells. The primary culture of human endometrial stromal cells was transfected with the hPR-A or hPR-B expression vector and the IGFBP-1 promoter construct p275CAT, which contains two functional progesterone response elements (PRE1 and PRE2) in decidualized stromal cells. Medroxyprogesterone acetate (MPA) increased the promoter activities ranging from 1.2- to 27-fold in cells cotransfected with hPR-A or hPR-B in eight endometrial specimens. The promoter activity increased by the hPR-A was significantly higher than hPR-B (15 +/- 8 vs. 4 +/- 2, mean +/- SD; n = 8, P < 0.005). Site-specific mutation showed that the induced activity by hPR-A was mediated through the PRE1 and PRE2 sites. Addition of hPR-B reduced the effect of hPR-A. The high transactivation capacity of hPR-A was also activated by other ligands, progesterone, Org 2058, and norethindrone. These observations indicate that hPR-A is a stronger transactivator than hPR-B for the IGFBP-1 promoter in endometrial stromal cells. Previous studies have shown the progestin-dependent production of IGFBP-1 correlates with its mRNA levels and transcription rate. Thus, we have determined the effect of hPR-A and hPR-B on the production of IGFBP-1 in stromal cells treated with MPA. The production rate in cells uniformly infected with AdPRA (recombinant Ad5-directed PR expression system) was significantly higher (P < 0.001) than the rate in uninfected cells and in cells infected with AdPRB or AdCMV (the Ad5 viral expression vector). This result, in concert with the promoter analysis, provides evidence that hPR-A is a strong inducer for the chromosomal IGFBP-1 gene in endometrial stromal cells.
在人类子宫内膜中，孕激素受体（PR）亚型hPR - A和hPR - B的水平在生殖周期中受到不同调节。孕激素显著增加hPR - A的含量，hPR - A是蜕膜化基质细胞中的主要亚型（1）。本研究的目的是确定hPR - A和hPR - B在人类子宫内膜基质细胞中转录激活孕激素依赖性靶基因的能力。我们检测了共转染hPR - A或hPR - B对子宫内膜基质细胞中人胰岛素样生长因子结合蛋白-1（IGFBP - 1）表达的影响。将人子宫内膜基质细胞原代培养物用hPR - A或hPR - B表达载体以及IGFBP - 1启动子构建体p275CAT进行转染，p275CAT在蜕膜化基质细胞中含有两个功能性孕激素反应元件（PRE1和PRE2）。醋酸甲羟孕酮（MPA）使八个子宫内膜标本中与hPR - A或hPR - B共转染的细胞中的启动子活性提高了1.2至27倍。hPR - A诱导的启动子活性显著高于hPR - B（15±8对4±2，平均值±标准差；n = 8，P < 0.005）。位点特异性突变表明，hPR - A诱导的活性是通过PRE1和PRE2位点介导的。添加hPR - B降低了hPR - A的作用。hPR - A的高转录激活能力也被其他配体、孕激素、Org 2058和炔诺酮激活。这些观察结果表明，在子宫内膜基质细胞中，对于IGFBP - 1启动子，hPR - A是比hPR - B更强的转录激活因子。先前的研究表明，孕激素依赖性的IGFBP - 1产生与其mRNA水平和转录速率相关。因此，我们确定了hPR - A和hPR - B对用MPA处理的基质细胞中IGFBP - 1产生的影响。用AdPRA（重组Ad5导向的PR表达系统）均匀感染的细胞中的产生率显著高于未感染细胞以及用AdPRB或AdCMV（Ad5病毒表达载体）感染的细胞中的产生率（P < 0.001）。这一结果与启动子分析一致，为hPR - A是子宫内膜基质细胞中染色体IGFBP - 1基因的强诱导剂提供了证据。
