Department of Obstetrics and Gynecology, Yamaguchi University Graduate School of Medicine, Ube 755-8505, Japan.
J Clin Endocrinol Metab. 2011 Jul;96(7):E1073-82. doi: 10.1210/jc.2010-2489. Epub 2011 May 4.
Progesterone differently regulates TNFα-induced gene expression of cyclooxygenase-2 (COX-2) and manganese superoxide dismutase (Mn-SOD) in human endometrial stromal cells (ESC).
The present study investigated the mechanisms by which TNFα and progesterone affect the expressions of COX-2 and Mn-SOD in ESC.
ESC were incubated with TNFα and progesterone. COX-2 and Mn-SOD mRNA expression was determined by real-time RT-PCR. Nuclear factor (NF)-κB binding to the promoter region or histone acetylation status of the NF-κB response element was analyzed by a chromatin immunoprecipitation assay.
TNFα increased COX-2 and Mn-SOD mRNA levels. Progesterone (10(-6) M) suppressed TNFα-induced COX-2 mRNA expression, whereas TNFα-induced Mn-SOD expression was not inhibited by progesterone. The inhibitory effect of progesterone was abolished by knockdown of progesterone receptors by small interfering RNA. Chromatin immunoprecipitation assay revealed that TNFα increased NF-κB binding at both the COX-2 promoter and the Mn-SOD enhancer and that progesterone inhibited only the NF-κB binding at the COX-2 promoter. The histone acetylation level of the NF-κB response element of the Mn-SOD enhancer was lower than that of the COX-2 promoter. However, when histone acetylation was induced by histone deacetylase inhibitors, progesterone inhibited the TNFα-induced NF-κB binding to the Mn-SOD enhancer.
TNFα increased COX-2 and Mn-SOD expression via NF-κB activation. Progesterone inhibited COX-2 expression by inhibiting the binding of NF-κB to its response element but did not inhibit TNFα-induced Mn-SOD expression. The gene-specific action of progesterone may be due to the difference in chromatin structure at the NF-κB response elements in the COX-2 promoter and Mn-SOD enhancer.
孕激素可调节人子宫内膜基质细胞中环氧化酶-2（COX-2）和锰超氧化物歧化酶（Mn-SOD）的 TNFα 诱导基因表达。
本研究旨在探讨 TNFα 和孕激素影响 ESC 中 COX-2 和 Mn-SOD 表达的机制。
用 TNFα 和孕激素孵育 ESC。通过实时 RT-PCR 测定 COX-2 和 Mn-SOD mRNA 的表达。通过染色质免疫沉淀分析测定核因子（NF）-κB 与启动子区域的结合或 NF-κB 反应元件的组蛋白乙酰化状态。
TNFα 增加 COX-2 和 Mn-SOD mRNA 水平。孕激素（10(-6) M）抑制 TNFα 诱导的 COX-2 mRNA 表达，但孕激素不抑制 TNFα 诱导的 Mn-SOD 表达。小干扰 RNA 敲低孕激素受体可消除孕激素的抑制作用。染色质免疫沉淀分析显示，TNFα 增加了 COX-2 启动子和 Mn-SOD 增强子上的 NF-κB 结合，而孕激素仅抑制了 COX-2 启动子上的 NF-κB 结合。Mn-SOD 增强子 NF-κB 反应元件的组蛋白乙酰化水平低于 COX-2 启动子。然而，当组蛋白去乙酰化酶抑制剂诱导组蛋白乙酰化时，孕激素抑制了 TNFα 诱导的 NF-κB 结合到 Mn-SOD 增强子。
TNFα 通过 NF-κB 激活增加 COX-2 和 Mn-SOD 的表达。孕激素通过抑制 NF-κB 与其反应元件的结合抑制 COX-2 表达，但不抑制 TNFα 诱导的 Mn-SOD 表达。孕激素的基因特异性作用可能是由于 COX-2 启动子和 Mn-SOD 增强子上 NF-κB 反应元件的染色质结构不同所致。
