In vivo chromatin remodeling events leading to inflammatory gene transcription under diabetic conditions
In vivo chromatin remodeling events leading to inflammatory gene transcription under diabetic conditions
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DOI：
10.1074/jbc.m311786200
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发表时间：
2004-04-23
影响因子：
4.8
通讯作者：
Natarajan, R
中科院分区：
文献类型：
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作者：
Miao, F;Gonzalo, IG;Natarajan, R
转录因子NF-kappaB（NF-kappaB）在调节炎症基因表达中发挥着关键作用。其效果可通过多种共激活剂进行优化，包括组蛋白乙酰转移酶 (HAT)，如 CBP/p300 和 p/CAF。有证据表明，模仿糖尿病的高葡萄糖 (HG) 条件可以激活 NF-κB 调节的炎症基因的转录。然而，潜在的体内转录和核染色质重塑事件尚不清楚。因此，我们在单核细胞中进行了染色质免疫沉淀 (ChIP) 测定，以确定 1) 在 HG 或糖尿病条件下与肿瘤坏死因子-α (TNF-α) 和相关 NF-κB 调节基因的启动子结合的染色质因子，2) 在此过程中乙酰化的组蛋白 H3 (HH3) 和 HH4 上的特定赖氨酸 (Lys (K)) 残基。 THP-1 单核细胞的 HG 处理增加了 NF-kappaB p65 的转录活性，CBP/p300 和 p/CAF 增强了这种转录活性。 ChIP 测定显示 HG 增加了 NF-kappaB p65、CPB 和 p/CAF 向 TNF-α 和 COX-2 启动子的募集。有趣的是，ChIP 检测还证明了 TNF-α 和 COX-2 启动子处的 HH3 在 Lys(9) 和 Lys(14) 处以及 HH4 在 Lys(5)、Lys(8) 和 Lys(12) 处伴随乙酰化。组蛋白脱乙酰酶 (HDAC) 亚型的过度表达抑制 p65 介导的 TNF-α 转录。相反，HDAC 抑制剂刺激基因转录和组蛋白乙酰化。最后，我们证明，与非糖尿病患者相比，1 型和 2 型糖尿病受试者的人血单核细胞中 TNF-α 和 COX-2 启动子的 HH3 乙酰化增加。这些结果首次表明，糖尿病可以增加体内 NF-κB 和 HAT 的募集，以及炎症基因启动子处的组蛋白乙酰化，从而导致染色质重塑和转录。
The transcription factor NF-kappaB ( NF-kappaB) plays a pivotal role in regulating inflammatory gene expression. Its effects are optimized by various coactivators including histone acetyltransferases (HAT) such as CBP/p300 and p/CAF. Evidence shows that high glucose (HG) conditions mimicking diabetes can activate the transcription of NF-kappaB-regulated inflammatory genes. However, the underlying in vivo transcription and nuclear chromatin remodeling events are unknown. We therefore carried out chromatin immunoprecipitation (ChIP) assays in monocytes to identify 1) chromatin factors bound to the promoters of tumor necrosis factor-alpha (TNF-alpha) and related NF-kappaB-regulated genes under HG or diabetic conditions, 2) specific lysine (Lys ( K)) residues on histone H3 (HH3) and HH4 acetylated in this process. HG treatment of THP-1 monocytes increased the transcriptional activity of NF-kappaB p65, which was augmented by CBP/ p300 and p/CAF. ChIP assays showed that HG increased the recruitment of NF-kappaB p65, CPB, and p/CAF to the TNF-alpha and COX-2 promoters. Interestingly, ChIP assays also demonstrated concomitant acetylation of HH3 at Lys(9) and Lys(14), and HH4 at Lys(5), Lys(8), and Lys(12) at the TNF-alpha and COX-2 promoters. Overexpression of histone deacetylase (HDAC) isoforms inhibited p65-mediated TNF-alpha transcription. In contrast, a HDAC inhibitor stimulated gene transcription and histone acetylation. Finally, we demonstrated increased HH3 acetylation at TNF-alpha and COX-2 promoters in human blood monocytes from type 1 and type 2 diabetic subjects relative to nondiabetic. These results show for the first time that diabetic conditions can increase in vivo recruitment of NF-kappaB and HATs, as well as histone acetylation at the promoters of inflammatory genes, leading to chromatin remodeling and transcription.