Inhibition of erythropoietin gene expression signaling involves the transcription factors GATA-2 and NF-κB
Inhibition of erythropoietin gene expression signaling involves the transcription factors GATA-2 and NF-κB
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DOI：
10.1096/fj.02-0168fje
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发表时间：
2002-11-01
期刊：
影响因子：
4.8
通讯作者：
Hellwig-Bürgel, T
中科院分区：
文献类型：
--
作者：
La Ferla, K;Reimann, C;Hellwig-Bürgel, T
慢性炎症和恶性疾病引起的贫血部分是由于促红细胞生成素（Epo）合成受损所致。促炎细胞因子白介素-1 (IL-1) 和肿瘤坏死因子 α (TNF-α) 抑制体外 Epo 基因表达和 Epo 蛋白分泌。然而，人们对这种抑制的分子机制知之甚少。人 Epo 启动子和 5' 侧翼区域包含多个正向或负向作用的转录因子识别序列。在此，我们研究了转录因子 GATA-2 和 NF-kappaB 在人肝癌细胞系 HepG2 中 IL-1β 和 TNF-α 调节 Epo 基因表达中的作用。电泳迁移率变动分析显示，用 IL-1beta 或 TNF-α 处理的细胞中 GATA-2 和 NF-kappaB DNA 结合增加。对萤火虫荧光素酶基因前面的 Epo 启动子序列进行的报告基因分析表明，细胞因子降低了 Epo 报告基因的活性。通过寡诱饵技术使 GATA-2 和 NF-κB 功能失活，可防止 IL-1β 和 TNF-α 对 Epo 产生的抑制。在用显性失活形式的 IkappaBalpha 稳定转染的 HepG2 细胞中，NF-kappaB 的激活受到抑制，而 Epo mRNA 水平和 Epo 分泌增加。因此，GATA-2和NF-κB似乎都参与了体外IL-1β和TNF-α对Epo基因表达的抑制，并且可能是体内炎症性疾病中Epo合成受损的原因。
The anemia of chronic inflammatory and malignant diseases is partly due to impaired synthesis of the hormone erythropoietin (Epo). The proinflammatory cytokines interleukin-1 (IL-1) and tumor necrosis factor alpha (TNF-alpha) suppress in vitro Epo gene expression and Epo protein secretion. However, the molecular mechanisms of this inhibition are poorly understood. The human Epo promoter and the 5' flanking region contain several recognition sequences for transcription factors acting either positively or negatively. Herein, we investigated the roles of the transcription factors GATA-2 and NF-kappaB in the modulation of Epo gene expression by IL-1beta and TNF-alpha in the human hepatoma cell line HepG2. Electrophoretic mobility shift assays revealed increased GATA-2 and NF-kappaB DNA binding in cells treated with IL-1beta or TNF-alpha. Reporter gene assays with a sequence from the Epo promoter in front of the firefly luciferase gene showed that the cytokines reduced Epo reporter gene activity. Functional inactivation of GATA-2 and NF-kappaB by oligo-decoy techniques prevented the inhibition of Epo production by IL-1beta and TNF-alpha. In HepG2 cells stably transfected with a dominant-negative form of IkappaBalpha, the activation of NF-kappaB was inhibited, while Epo mRNA levels and Epo secretion increased. Thus, both GATA-2 and NF-kappaB seem to be involved in the suppression of Epo gene expression by IL-1beta and TNF-alpha in vitro and may be responsible for impaired Epo synthesis in inflammatory diseases in vivo.