AVIAN OSTEOCLASTS AS ESTROGEN TARGET-CELLS
AVIAN OSTEOCLASTS AS ESTROGEN TARGET-CELLS
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DOI：
10.1073/pnas.88.15.6613
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发表时间：
1991-08-01
影响因子：
11.1
通讯作者：
SPELSBERG, TC
中科院分区：
文献类型：
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作者：
OURSLER, MJ;OSDOBY, P;SPELSBERG, TC
虽然17-β-雌二醇（雌激素）对骨转换的体内作用已被证明主要通过影响破骨细胞介导的骨吸收而发生，但雌激素减少骨吸收的机制尚不清楚。为了解决这个问题，我们已经检查了真实的破骨细胞的证据，直接破骨细胞反应雌激素在体外。使用与磁珠偶联的破骨细胞特异性单克隆抗体，从维持在低钙饮食的鸟类中获得高度纯化（> 90%）的活的禽类破骨细胞。分离的细胞直接分析雌激素受体（ER）水平或培养，以评估雌激素的生物学效应。北方印迹分析显示，破骨细胞中的5.2-磷酸酶mRNA与人ER mRNA的cDNA杂交。通过Western印迹分析，抗人ER抗体识别破骨细胞提取物中66 kDa和140 kDa的蛋白质。66 kDa的大小与报道的人ER的大小非常一致。雌激素与完整的活破骨细胞的核结合是类固醇特异性的和可饱和的，每个核结合5662 +/- 1420个分子（平均值+/- SEM）。破骨细胞的体外雌激素反应包括剂量依赖性的再吸收减少以及核原癌基因mRNA水平的增加。这些观察结果表明，破骨细胞能够直接响应雌激素在体内。
Although in vivo effects of 17-beta-estradiol (estrogen) on bone turnover have been shown to occur mainly through influences on osteoclast-mediated bone resorption, the mechanism by which estrogen reduces bone resorption is unclear. To approach this question, we have examined authentic osteoclasts for evidence of a direct osteoclast response to estrogen in vitro. Highly purified (> 90%) viable avian osteoclasts from birds maintained on a low calcium diet were obtained using an osteoclast-specific monoclonal antibody coupled to magnetic beads. Isolated cells were either analyzed directly for estrogen receptor (ER) levels or cultured to assess the biological effects of estrogen. Northern blot analysis revealed a 5.2-kilobase mRNA that hybridized with a cDNA to human ER mRNA in the osteoclasts. An anti-human ER antibody recognized proteins of 66 kDa and 140 kDa in osteoclast extracts by Western blot analysis. The 66-kDa size is in close agreement with the reported size of the human ER. Nuclear binding of estrogen to intact viable osteoclasts was steroid-specific and saturable, with 5662 +/- 1420 molecules bound per nucleus (mean +/- SEM). In vitro estrogen responses in osteoclasts included a dose-dependent decrease in resorption as well as an increase in nuclear protooncogene mRNA levels. These observations indicate that osteoclasts are capable of directly responding to estrogen in vivo.