Genome-wide identification of palmitate-regulated immediate early genes and target genes in pancreatic beta-cells reveals a central role of NF-κB
Genome-wide identification of palmitate-regulated immediate early genes and target genes in pancreatic beta-cells reveals a central role of NF-κB
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DOI：
10.1007/s11033-012-1503-5
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发表时间：
2012-06-01
影响因子：
2.8
通讯作者：
Cho, Young Min
中科院分区：
文献类型：
--
作者：
Choi, Hyung Jin;Hwang, Seungwoo;Cho, Young Min
游离脂肪酸诱导的胰岛β细胞功能障碍在2型糖尿病的发病机制中起关键作用。我们进行了基因表达微阵列分析，全面调查棕榈酸调控基因的转录机制在胰腺β细胞在体外。特别是，在存在或不存在放线菌酮（CHX）的情况下，用棕榈酸酯处理小鼠胰腺β TC 3细胞，其阻断蛋白质合成，从而使我们能够区分立即早期基因（IEG）与其靶基因。微阵列实验鉴定了34个棕榈酸调节的IEG和74个棕榈酸调节的靶基因。计算机启动子分析显示NF-κ B B的转录因子结合位点过度表达，调节约三分之一的棕榈酸调节靶基因。在用CHX处理的细胞中，棕榈酸酯显示nfkb 1上调，表明NF-κ B可能是IEG。对27个具有NF-κ B结合位点的棕榈酸调节基因的功能富集分析显示，参与免疫反应、炎症反应、防御反应、趋化性、细胞增殖调节和细胞死亡途径调节的基因过度表达。电泳迁移率变动分析表明，棕榈酸刺激NF-κ B B的活性，在存在和不存在的CHX。总之，通过鉴定IEGs和靶基因，本研究描绘了棕榈酸酯诱导的胰腺β细胞炎症和细胞增殖/死亡的转录机制的综合观点，我们的数据证明了NF-κ B的核心作用。
Free fatty acid-induced pancreatic beta-cell dysfunction plays a key role in the pathogenesis of type 2 diabetes. We conducted gene expression microarray analysis to comprehensively investigate the transcription machinery of palmitate-regulated genes in pancreatic beta-cells in vitro. In particular, mouse pancreatic beta TC3 cells were treated with palmitate in the presence or absence of cycloheximide (CHX), which blocks protein synthesis and thereby allows us to distinguish immediate early genes (IEGs) from their target genes. The microarray experiments identified 34 palmitate-regulated IEGs and 74 palmitate-regulated target genes. In silico promoter analysis revealed that transcription factor binding sites for NF-kappa B were over-represented, regulating approximately one-third of the palmitate-regulated target genes. In cells treated with CHX, nfkb1 showed an up-regulation by palmitate, suggesting that NF-kappa B could be an IEG. Functional enrichment analysis of 27 palmitate-regulated genes with NF-kappa B binding sites showed an over-representation of genes involved in immune response, inflammatory response, defense response, taxis, regulation of cell proliferation, and regulation of cell death pathways. Electrophoretic mobility shift assay showed that palmitate stimulates NF-kappa B activity both in the presence and absence of CHX. In conclusion, by identifying IEGs and target genes, the present study depicted a comprehensive view of transcription machinery underlying palmitate-induced inflammation and cell proliferation/death in pancreatic beta-cells and our data demonstrated the central role of NF-kappa B.