Department of Nursing, Hsin Sheng College of Medical Care and Management, Taoyuan, Taiwan.
Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
J Steroid Biochem Mol Biol. 2019 Jan;185:200-211. doi: 10.1016/j.jsbmb.2018.09.002. Epub 2018 Sep 5.
Bisphenol A (BPA), an endocrine-disrupting chemical, is capable of producing reproductive toxicity. BPA results in mitochondrial DNA (mtDNA) deletion and mitochondrial dysfunction; however, the effect of BPA on the mitochondria of ovarian granulosa cells is not clear. Further, 1,25-dihydroxyvitamin D (1,25D) may play a role in reproduction, because its receptor, VDR, contributes to the inhibition of oxidative stress and predominantly exists in the nuclei of granulosa cells. Hence, the role of 1,25D in BPA-mediated effects on mitochondrial function was examined in this study. Primary rat granulosa cells treated with BPA, 1,25D, or both were subjected to molecular/biochemical assays to measure cell survival, mtDNA content, mtDNA deletion, superoxide dismutase activity, levels of proteins related to mitochondrial biogenesis, and mitochondrial function. We found that cell viability was dose-dependently reduced and reactive oxygen species (ROS) levels were increased by BPA treatment. BPA administration elevated Mn-superoxide dismutase (MnSOD) expression but negatively regulated total SOD activity. 1,25D treatment alone increased 17β-estradiol secretion, ATP production, and cellular oxygen consumption. In cells treated with both agents, 1,25D enhanced BPA-induced MnSOD protein upregulation and blocked the BPA-mediated decline in total SOD activity. Furthermore, 1,25D attenuated BPA-mediated mtDNA deletion but showed no effect on BPA-induced increases in mtDNA content. Although BPA had no influence on the levels of peroxisome proliferator-activated receptor-γ coactivator-1 α, nuclear respiratory factor-1, mitochondrial transcription factor A, or cytochrome c oxidase subunit IV, 1,25D plus BPA markedly increased mitochondrial biogenesis-related protein expression via the PI3K-Akt pathway. Moreover, BPA-mediated negative regulation of cytochrome c oxidase subunit I levels and 17β-estradiol secretion was attenuated by 1,25D pre-treatment. Our results suggest that 1,25D attenuates BPA-induced decreases in 17β-estradiol and that treatment with 1,25D plus BPA regulates granulosa cell mitochondria by elevating mitochondrial biogenesis-related protein levels.
双酚 A（BPA）是一种内分泌干扰化学物质，能够产生生殖毒性。BPA 导致线粒体 DNA（mtDNA）缺失和线粒体功能障碍；然而，BPA 对卵巢颗粒细胞线粒体的影响尚不清楚。此外，1,25-二羟维生素 D（1,25D）可能在生殖中发挥作用，因为其受体 VDR 有助于抑制氧化应激，并且主要存在于颗粒细胞的核内。因此，本研究检测了 1,25D 在 BPA 介导的线粒体功能中的作用。用 BPA、1,25D 或两者处理原代大鼠颗粒细胞，进行分子/生化测定，以测量细胞存活率、mtDNA 含量、mtDNA 缺失、超氧化物歧化酶活性、与线粒体生物发生相关的蛋白质水平以及线粒体功能。我们发现，细胞活力随 BPA 处理剂量依赖性降低，活性氧（ROS）水平升高。BPA 给药上调 Mn-超氧化物歧化酶（MnSOD）表达，但负调节总 SOD 活性。1,25D 单独处理可增加 17β-雌二醇分泌、ATP 产生和细胞耗氧量。在两种药物处理的细胞中，1,25D 增强了 BPA 诱导的 MnSOD 蛋白上调，并阻止了 BPA 介导的总 SOD 活性下降。此外，1,25D 减弱了 BPA 介导的 mtDNA 缺失，但对 BPA 诱导的 mtDNA 含量增加没有影响。尽管 BPA 对过氧化物酶体增殖物激活受体-γ 共激活因子-1α、核呼吸因子-1、线粒体转录因子 A 或细胞色素 c 氧化酶亚基 IV 的水平没有影响，但 1,25D 加 BPA 通过 PI3K-Akt 通路显著增加了与线粒体生物发生相关的蛋白质表达。此外，1,25D 预处理减弱了 BPA 介导的细胞色素 c 氧化酶亚基 I 水平和 17β-雌二醇分泌的下调。我们的结果表明，1,25D 减弱了 BPA 诱导的 17β-雌二醇降低，用 1,25D 加 BPA 处理通过提高与线粒体生物发生相关的蛋白质水平来调节颗粒细胞线粒体。
