Department of Biochemistry and Molecular Biology, Monash University, Wellington Road, Clayton, Victoria 3800, Australia.
Endocrinology. 2010 Jan;151(1):185-94. doi: 10.1210/en.2009-0590. Epub 2009 Dec 4.
During the stress response and metabolic fasting, glucocorticoids acting via the glucocorticoid receptor (GR) stimulate hepatic glucose production by activating specific gluconeogenic enzyme target genes. To characterize novel direct GR-regulated hepatic target genes under glucocorticoid control, we performed a whole genome gene expression microarray using dexamethasone-treated GR-null mice. Strongly induced previously characterized genes included phosphoenolpyruvate carboxykinase, serine dehydratase, tyrosine oxygenase, lipin 1, metallothionine, and cdkn1A. Novel induced genes included Ddit4, Fkbp5, Megf9, Sult1e1, and Sult1d1, and all were verified by real-time PCR. Sult1d1, a sulfotransferase, is a member of a large superfamily of detoxification enzymes and has an important role in the inactivation of endogenous dopamine-derived compounds, including the catecholamines. Treatment of primary mouse hepatocytes with dexamethasone for 6 h dramatically increased Sult1d1 mRNA levels, whereas cotreatment with RU-486, a GR antagonist, blocked induction by dexamethasone. Sult1d1 mRNA levels were also increased by dexamethasone in the kidney, a major site of Sult1d1 synthesis. Sult1d1 mRNA was localized by in situ hybridization to renal collecting ducts and was rapidly induced by glucocorticoids in renal inner medullary collecting duct (IMCD3) cells. Hepatic and renal Sult1d1 enzymatic activity was significantly induced in vivo in wild-type mice 6 h after dexamethasone treatment. Chromatin immunoprecipitation assay analysis upstream of the Sult1d1 gene promoter identified a glucocorticoid response element close to the neighboring glucocorticoid-responsive estrogen sulfotransferase Sult1e1 gene, indicating that both genes potentially share a common glucocorticoid response element. These results suggest that Sult1d1 in mice is directly induced by glucocorticoids and may attenuate elevated catecholamine activity during the stress response.
在应激反应和代谢性禁食期间，糖皮质激素通过糖皮质激素受体 (GR) 作用，通过激活特定的糖异生酶靶基因来刺激肝葡萄糖生成。为了描述糖皮质激素控制下新的直接 GR 调节的肝靶基因，我们使用地塞米松处理的 GR 缺失小鼠进行了全基因组基因表达微阵列分析。以前表征的强烈诱导基因包括磷酸烯醇丙酮酸羧激酶、丝氨酸脱水酶、酪氨酸加氧酶、脂肪酶 1、金属硫蛋白和 cdkn1A。新诱导的基因包括 Ddit4、Fkbp5、Megf9、Sult1e1 和 Sult1d1，所有基因均通过实时 PCR 验证。Sult1d1 是一种磺基转移酶，是解毒酶大家族的成员，在失活内源性多巴胺衍生化合物（包括儿茶酚胺）方面具有重要作用。用地塞米松处理原代小鼠肝细胞 6 小时可显著增加 Sult1d1 mRNA 水平，而用 GR 拮抗剂 RU-486 共同处理则阻断了地塞米松的诱导作用。地塞米松也能在肾脏中增加 Sult1d1 mRNA 水平，肾脏是 Sult1d1 合成的主要部位。原位杂交将 Sult1d1 mRNA 定位于肾脏集合管，地塞米松可快速诱导肾髓质集合管 (IMCD3) 细胞中 Sult1d1 的表达。在野生型小鼠中，地塞米松处理 6 小时后，肝和肾 Sult1d1 酶活性显著在体内诱导。Sult1d1 基因启动子上游的染色质免疫沉淀分析鉴定出一个靠近相邻糖皮质激素反应雌激素磺基转移酶 Sult1e1 基因的糖皮质激素反应元件，表明这两个基因可能共享一个共同的糖皮质激素反应元件。这些结果表明，在小鼠中 Sult1d1 直接受糖皮质激素诱导，可能在应激反应期间减轻升高的儿茶酚胺活性。
