Guo Shihui, Chen Zijin, Dong Yingying, Ni Yingdong, Zhao Ruqian, Ma Wenqiang
Key Laboratory of Animal Physiology and Biochemistry, Ministry of Agriculture and Rural Affairs, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China.
MOE Joint International Research Laboratory of Animal Health & Food Safety, Nanjing Agricultural University, Nanjing 210095, China.
Biology (Basel). 2023 Jan 28;12(2):197. doi: 10.3390/biology12020197.
Numerous studies have discovered that chronic stress induces metabolic disorders by affecting iron and zinc metabolism, but the relationship between chronic stress and copper metabolism remains unclear. Here, we explore the influence of chronic corticosterone (CORT) exposure on copper metabolism and its regulatory mechanism in mice. Mice were treated with 100 μg/mL CORT in drinking water for a 4-week trial. We found that CORT treatment resulted in a significant decrease in plasma copper level, plasma ceruloplasmin activity, plasma and liver Cu/Zn-SOD activity, hepatic copper content, and liver metallothionein content in mice. CORT treatment led to the reduction in duodenal expression of copper transporter 1 (CTR1), duodenal cytochrome b (DCYTB), and ATPase copper-transporting alpha (ATP7A) at the mRNA and protein level in mice. CORT treatment activated nuclear glucocorticoid receptor (GR) and down-regulated CRT1 expression in Caco-2 cells, whereas these phenotypes were reversible by an antagonist of GR, RU486. Chromatin immunoprecipitation analysis revealed that GR bound to the promoter in Caco-2 cells. Transient transfection assays in Caco-2 cells demonstrated that the promoter was responsive to the CORT-activated glucocorticoid receptor, whereas mutation/deletion of the glucocorticoid receptor element (GRE) markedly impaired activation of the promoter. In addition, CORT-induced downregulation of promoter activity was markedly attenuated in Caco-2 cells when RU486 was added. These findings present a novel molecular target for CORT that down-regulates intestinal CTR1 expression via GR-mediated trans-repression in mice.
大量研究发现，慢性应激通过影响铁和锌代谢诱导代谢紊乱，但慢性应激与铜代谢之间的关系仍不清楚。在此，我们探讨慢性皮质酮（CORT）暴露对小鼠铜代谢的影响及其调控机制。小鼠在饮用水中接受100μg/mL CORT处理，进行为期4周的试验。我们发现，CORT处理导致小鼠血浆铜水平、血浆铜蓝蛋白活性、血浆和肝脏铜/锌超氧化物歧化酶活性、肝脏铜含量以及肝脏金属硫蛋白含量显著降低。CORT处理导致小鼠十二指肠铜转运蛋白1（CTR1）、十二指肠细胞色素b（DCYTB）和ATP酶铜转运α（ATP7A）在mRNA和蛋白质水平的表达降低。CORT处理激活了核糖皮质激素受体（GR）并下调了Caco-2细胞中CTR1的表达，而GR拮抗剂RU486可使这些表型逆转。染色质免疫沉淀分析显示，GR与Caco-2细胞中的启动子结合。Caco-2细胞中的瞬时转染试验表明，该启动子对CORT激活的糖皮质激素受体有反应，而糖皮质激素反应元件（GRE）的突变/缺失显著损害了启动子的激活。此外，当加入RU486时，CORT诱导的启动子活性下调在Caco-2细胞中明显减弱。这些发现揭示了CORT通过GR介导的反式抑制下调小鼠肠道CTR1表达的新分子靶点。
