Department of Anesthesiology, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan.
Department of Anesthesiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
Am J Chin Med. 2021;49(4):901-923. doi: 10.1142/S0192415X21500439. Epub 2021 Apr 9.
Our previous study showed that estrogen can induce mitochondrial adenosine triphosphate (ATP) synthesis-associated gene expressions and osteoblast maturation. Genistein, a phytoestrogenic isoflavone that is widely found in various foods and traditional herb products, is beneficial for osteogenesis by selectively triggering estrogen receptor alpha (ER[Formula: see text] expression. In this study, we further investigated the mechanisms of genistein-induced energy production and osteoblast activation. Exposure of rat calvarial osteoblasts and human U-2 OS cells to genistein triggered osteoblast activation without affecting cell survival. Treatment with genistein time-dependently induced ER[Formula: see text] mRNA and protein expressions in rat calvarial osteoblasts. Analyses by confocal microscopy and immunoblotting showed that genistein stimulated translocation of ER[Formula: see text] from the cytoplasm to mitochondria. Subsequently, expressions of mitochondrial cytochrome c oxidase (COX) I and II mRNAs and proteins in primary rat osteoblasts were induced after exposure to genistein. Knocking-down ER[Formula: see text] concurrently inhibited genistein-induced COX I and II mRNA expressions. In addition, mitochondrial complex enzyme activities, the mitochondrial membrane potential, and cellular ATP levels in rat calvarial osteoblasts were time-dependently augmented by genistein. Suppressing ER[Formula: see text] expression instantaneously lowered genistein-induced enhancements of mitochondrial energy production and osteoblast activation. Effects of genistein on ER[Formula: see text] translocation, COX I and II mRNA expressions, ATP synthesis, and osteoblast activation were further confirmed in human U-2 OS cells. This study showed that genistein can stimulate energy production and consequent osteoblast activation via inducing ER[Formula: see text]-mediated mitochondrial ATP synthesis-linked gene expressions.
我们之前的研究表明，雌激素可以诱导与三磷酸腺苷（ATP）合成相关的基因表达和成骨细胞成熟。染料木黄酮是一种广泛存在于各种食物和传统草药产品中的植物雌激素，它通过选择性地触发雌激素受体α（ERα）表达，有益于成骨作用。在这项研究中，我们进一步研究了染料木黄酮诱导能量产生和成骨细胞激活的机制。暴露于染料木黄酮的大鼠颅骨成骨细胞和人 U-2 OS 细胞会触发成骨细胞激活，而不影响细胞存活。用染料木黄酮处理大鼠颅骨成骨细胞会时间依赖性地诱导 ERα mRNA 和蛋白表达。共聚焦显微镜和免疫印迹分析表明，染料木黄酮刺激 ERα从细胞质向线粒体转位。随后，在用染料木黄酮处理后，初级大鼠成骨细胞中的线粒体细胞色素 c 氧化酶（COX）I 和 II mRNA 和蛋白表达被诱导。敲低 ERα 同时抑制了染料木黄酮诱导的 COX I 和 II mRNA 表达。此外，大鼠颅骨成骨细胞中的线粒体复合酶活性、线粒体膜电位和细胞内 ATP 水平也随染料木黄酮的作用而时间依赖性增加。瞬时抑制 ERα 表达会降低染料木黄酮诱导的线粒体能量产生和成骨细胞激活的增强作用。在人 U-2 OS 细胞中进一步证实了染料木黄酮对 ERα 易位、COX I 和 II mRNA 表达、ATP 合成和成骨细胞激活的作用。本研究表明，染料木黄酮可以通过诱导 ERα 介导的与线粒体 ATP 合成相关的基因表达来刺激能量产生和随后的成骨细胞激活。
