Binding of NF-kappaB p65 subunit to the promoter elements is involved in LPS-induced transactivation of miRNA genes in human biliary epithelial cells.
Binding of NF-kappaB p65 subunit to the promoter elements is involved in LPS-induced transactivation of miRNA genes in human biliary epithelial cells.
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DOI：
10.1093/nar/gkq056
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发表时间：
2010-06
影响因子：
14.9
通讯作者：
Chen XM
中科院分区：
文献类型：
--
作者：
Zhou R;Hu G;Gong AY;Chen XM
人类miRNA基因大部分由聚合酶II转录，可归类为II类基因，类似于蛋白质编码基因。尽管目前对mirna的研究主要集中在生理和病理功能上，但其转录调控的分子机制在很大程度上是未知的。我们最近报道了脂多糖（LPS）改变人胆道上皮细胞成熟miRNA的表达谱。在本研究中，我们测试了转录因子NF-κB在lps诱导的部分miRNA基因转录中的作用。在培养的人胆道上皮细胞中，大多数lps上调的成熟mirna中，潜在的NF-κB结合位点在其相应基因的假定启动子元件中被鉴定出来。IKK2抑制剂SC-514对NF-κB活化的抑制，阻断了lps诱导的一部分pri- mirna的上调，包括pri-miR-17-92、pri-miR-125b-1、pri-miR-21、pri-miR-23b-27b-24-1、pri-miR-30b、pri-miR-130a和pri-miR-29a。此外，通过染色质免疫沉淀分析鉴定了NF-κB p65亚基与mir-17-92、mir-125b-1、mir-21、mir-23b-27b-24-1、mir-30b和mir-130a基因的启动子元件的直接结合，并通过荧光素酶报告基因试验证实了这一点。因此，在人胆道上皮细胞中，一部分miRNA基因通过LPS诱导的NF-κB激活受到调控，提示NF-κB通路在miRNA基因的转录调控中发挥作用。
The majority of human miRNA genes is transcribed by polymerase II and can be classified as class II genes similar to protein-coding genes. Whereas current research on miRNAs has focused on the physiological and pathological functions, the molecular mechanisms underlying their transcriptional regulation are largely unknown. We recently reported that lipopolysaccharide (LPS) alters mature miRNA expression profile in human biliary epithelial cells. In this study, we tested the role of transcription factor NF-κB in LPS-induced transcription of select miRNA genes. Of the majority of LPS-up-regulated mature miRNAs in cultured human biliary epithelial cells, potential NF-κB binding sites were identified in the putative promoter elements of their corresponding genes. Inhibition of NF-κB activation by SC-514, an IKK2 inhibitor, blocked LPS-induced up-regulation of a subset of pri-miRNAs, including pri-miR-17-92, pri-miR-125b-1, pri-miR-21, pri-miR-23b-27b-24-1, pri-miR-30b, pri-miR-130a and pri-miR-29a. Moreover, direct binding of NF-κB p65 subunit to the promoter elements of mir-17-92, mir-125b-1, mir-21, mir-23b-27b-24-1, mir-30b and mir-130a genes was identified by chromatin immunoprecipitation analysis and confirmed by the luciferase reporter assay. Thus, a subset of miRNA genes is regulated in human biliary epithelial cells through NF-κB activation induced by LPS, suggesting a role of the NF-κB pathway in the transcriptional regulation of miRNA genes.