Nishimoto Fumihito, Sakata Masahiro, Minekawa Ryoko, Okamoto Yoko, Miyake Asako, Isobe Aki, Yamamoto Toshiya, Takeda Takashi, Ishida Emi, Sawada Kenjiro, Morishige Ken-Ichiro, Kimura Tadashi
Department of Obstetrics and Gynecology, Osaka University Faculty of Medicine, Suita City, Osaka, Japan.
Endocrinology. 2009 Apr;150(4):1801-8. doi: 10.1210/en.2008-0949. Epub 2008 Nov 20.
Placenta growth factor (PlGF) is a placental angiogenic factor. Metal-responsive transcription factor (MTF)-1 was reported to take part in the hypoxic induction of PlGF in RAS-transformed mouse fibroblasts. We contrarily showed that PlGF mRNA and protein levels decreased under hypoxia in a choriocarcinoma BeWo cell line derived from trophoblast. In this report, we examined whether hypoxia-dependent regulation of the PlGF gene in these cells also depends on MTF-1. We analyzed the effect of hypoxia on MTF-1 expression, and it was revealed to be decreased. Moreover, MTF-1 small interfering RNA treatment decreased PlGF mRNA level. To investigate the transcription of PlGF under hypoxia, we cloned promoter region of the human PlGF. Promoter deletion analysis suggested that triple repeats of metal-responsive element located between -511 and -468 bp in the promoter are important for the hypoxic regulation of PlGF. Treatment with MTF-1 small interfering RNA resulted in the significant decreased luciferase activity in PlGF reporter constructs. Chromatin immunoprecipitation showed the binding of the MTF-1 protein to the promoter region. We examined MTF-1 immunoreactivity in trophoblasts of term placental tissue from patients with normal pregnancies and preeclampsia, which represents a condition of placental hypoxia. Immunoreactivity of the MTF-1 protein was decreased in placentas from pregnant women with preeclampsia when compared with those from normal pregnant women. Taken together, these findings suggest that MTF-1 is involved in hypoxia-dependent regulation of PlGF in trophoblast-derived cells.
胎盘生长因子（PlGF）是一种胎盘血管生成因子。据报道，金属反应转录因子（MTF）-1参与RAS转化的小鼠成纤维细胞中PlGF的低氧诱导。相反，我们发现源自滋养层的绒毛膜癌BeWo细胞系在低氧条件下PlGF mRNA和蛋白水平降低。在本报告中，我们研究了这些细胞中PlGF基因的低氧依赖性调节是否也依赖于MTF-1。我们分析了低氧对MTF-1表达的影响，发现其表达降低。此外，MTF-1小干扰RNA处理降低了PlGF mRNA水平。为了研究低氧条件下PlGF的转录情况，我们克隆了人PlGF的启动子区域。启动子缺失分析表明，启动子中位于-511至-468 bp之间的金属反应元件的三重重复对于PlGF的低氧调节很重要。用MTF-1小干扰RNA处理导致PlGF报告基因构建体中的荧光素酶活性显著降低。染色质免疫沉淀显示MTF-1蛋白与启动子区域结合。我们检测了正常妊娠和先兆子痫患者足月胎盘组织滋养层中MTF-1的免疫反应性，先兆子痫代表胎盘低氧状态。与正常孕妇的胎盘相比，先兆子痫孕妇胎盘中MTF-1蛋白的免疫反应性降低。综上所述，这些发现表明MTF-1参与了滋养层来源细胞中PlGF的低氧依赖性调节。
