Loganathan Neruja, McIlwraith Emma K, Belsham Denise D
Department of Physiology, University of Toronto, Toronto, Ontario, Canada.
Department of Obstetrics, University of Toronto, Toronto, Ontario, Canada.
Endocrinology. 2020 Nov 1;161(11). doi: 10.1210/endocr/bqaa170.
Bisphenol A (BPA), a ubiquitous endocrine-disrupting chemical, interferes with reproduction and is also considered an obesogen. The neuropeptide Y (NPY) neurons of the hypothalamus control both food intake and reproduction and have emerged as potential targets of BPA. These functionally diverse subpopulations of NPY neurons are differentially regulated by peripheral signals, such as estrogen and leptin. Whether BPA also differentially alters Npy expression in subpopulations of NPY neurons, contributing to BPA-induced endocrine dysfunction is unclear. We investigated the response of 6 immortalized hypothalamic NPY-expressing cell lines to BPA treatment. BPA upregulated Npy mRNA expression in 4 cell lines (mHypoA-59, mHypoE-41, mHypoA-2/12, mHypoE-42), and downregulated Npy in 2 lines (mHypoE-46, mHypoE-44). This differential expression of Npy occurred concurrently with differential expression of estrogen receptor mRNA levels. Inhibition of G-protein coupled estrogen receptor GPR30 or estrogen receptor β prevented the BPA-mediated decrease in Npy, whereas inhibition of energy sensor 5' adenosine monophosphate-activated protein kinase (AMPK) with compound C prevented BPA-induced increase in Npy. BPA also altered neuroinflammatory and oxidative stress markers in both mHypoA-59 and mHypoE-46 cell lines despite the differential regulation of Npy. Remarkably, treatment with BPA in an antioxidant-rich media, Neurobasal A (NBA), or with reactive oxygen species scavenger tauroursodeoxycholic acid mitigated the BPA-induced increase and decrease in Npy. Furthermore, 2 antioxidant species from NBA-N-acetylcysteine and vitamin B6-diminished the induction of Npy in the mHypoA-59 cells, demonstrating these supplements can counteract BPA-induced dysregulation in certain subpopulations. Overall, these results illustrate the differential regulation of Npy by BPA in neuronal subpopulations, and point to oxidative stress as a pathway that can be targeted to block BPA-induced Npy dysregulation in hypothalamic neurons.
双酚A（BPA）是一种普遍存在的内分泌干扰化学物质，会干扰生殖功能，也被认为是一种致肥胖物。下丘脑的神经肽Y（NPY）神经元控制食物摄入和生殖功能，已成为BPA的潜在作用靶点。这些功能多样的NPY神经元亚群受到外周信号（如雌激素和瘦素）的不同调节。BPA是否也会差异地改变NPY神经元亚群中Npy的表达，从而导致BPA诱导的内分泌功能障碍尚不清楚。我们研究了6种永生化下丘脑NPY表达细胞系对BPA处理的反应。BPA上调了4种细胞系（mHypoA-59、mHypoE-41、mHypoA-2/12、mHypoE-42）中Npy mRNA的表达，下调了2种细胞系（mHypoE-46、mHypoE-44）中Npy的表达。Npy的这种差异表达与雌激素受体mRNA水平的差异表达同时发生。抑制G蛋白偶联雌激素受体GPR30或雌激素受体β可阻止BPA介导的Npy降低，而用化合物C抑制能量传感器5'-腺苷单磷酸激活蛋白激酶（AMPK）可阻止BPA诱导的Npy增加。尽管Npy受到不同调节，但BPA也改变了mHypoA-59和mHypoE-46细胞系中的神经炎症和氧化应激标志物。值得注意的是，在富含抗氧化剂的培养基Neurobasal A（NBA）中用BPA处理，或用活性氧清除剂牛磺熊去氧胆酸处理，可减轻BPA诱导的Npy增加和降低。此外，NBA中的两种抗氧化剂N-乙酰半胱氨酸和维生素B6减少了mHypoA-59细胞中Npy的诱导，表明这些补充剂可以抵消BPA在某些亚群中诱导的失调。总体而言，这些结果说明了BPA在神经元亚群中对Npy的差异调节，并指出氧化应激是一条可以靶向阻断BPA诱导下丘脑神经元中Npy失调的途径。
