Protein kinase C pathway is involved in transcriptional regulation of C-reactive protein synthesis in human hepatocytes
Protein kinase C pathway is involved in transcriptional regulation of C-reactive protein synthesis in human hepatocytes
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DOI：
10.1161/01.atv.0000150041.81963.68
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发表时间：
2005-01-01
影响因子：
8.7
通讯作者：
Torzewski, J
中科院分区：
文献类型：
--
作者：
Ivashchenko, Y;Kramer, F;Torzewski, J
目的 - C 反应蛋白 (CRP) 是急性期蛋白的原型，也是心血管危险因素。白细胞介素-1β (IL-1beta) 和 IL-6 刺激肝细胞中的 CRP 合成。我们寻找调节 CRP 表达的其他途径。方法和结果 - 用 IL-1beta、IL-6 和蛋白激酶 C (PKC) 激活剂佛波醇 12,13-二丁酸酯 (PDBu) 处理原代人肝细胞 (PHH)。通过定量RT-PCR和ELISA分析CRP。 PDBu 显着诱导 CRP 转录 21.0+/-9.24 倍，蛋白质释放 2.9+/-0.5 倍。在稳定转染 1-kb CRP 启动子的肝癌 G2 (HepG2) 细胞（HepG2-ABEK14 细胞）中详细研究了转录调控。在这些细胞中，PDBu 显着诱导 CRP 转录 5.39+/-0.66 倍。双吲哚基马来酰亚胺衍生物 LY333531 的竞争性抑制消除了 PDBu 介导的启动子激活。 IkappaB 激酶抑制剂 I229 的竞争性抑制也抑制 PDBu 的作用。重要的是，IL-8 显着诱导 PHH 中 CRP 释放 58.675+/-19.1 倍，可被 LY333531 阻断。 结论 - 这项研究描述了 CRP 基因表达的一种新型 PKC 依赖性转录调节，与经典的 IL-1beta 和 IL-6 途径类似，它仅在肝细胞中起作用。它还将 IL-8 确定为潜在的生理 PKC 激活剂。 HepG2-ABEK14 细胞可用于高通量筛选，以确定 CRP 合成抑制剂，从而预防心血管疾病。
Objective - C-Reactive protein (CRP) is the prototype acute phase protein and a cardiovascular risk factor. Interleukin-1beta (IL-1beta) and IL-6 stimulate CRP synthesis in hepatocytes. We searched for additional pathways regulating CRP expression.Methods and Results - Primary human hepatocytes (PHHs) were treated with IL-1beta, IL-6, and protein kinase C (PKC) activator phorbol 12,13-dibutyrate (PDBu). CRP was analyzed by quantitative RT-PCR and ELISA. PDBu significantly induced CRP transcription by 21.0+/-9.24-fold and protein release by 2.9+/-0.5-fold. Transcriptional regulation was studied in detail in hepatoma G2 (HepG2) cells stably transfected with the 1-kb CRP promoter (HepG2-ABEK14 cells). In these cells, PDBu significantly induced CRP transcription by 5.39+/-0.66-fold. Competetive inhibition with bisindolylmaleimide derivative LY333531 abolished PDBu-mediated promoter activation. Competetive inhibition with IkappaB kinase inhibitor I229 also inhibited PDBu effects. Importantly, IL-8 significantly induced CRP release in PHHs by 58.675+/-19.1-fold, which was blockable by LY333531.Conclusions - This study describes a novel PKC-dependent transcriptional regulation of CRP gene expression, which, in analogy to the classical IL-1beta and IL-6 pathways, is operational in hepatocytes only. It also identifies IL-8 as a potential physiological PKC activator. HepG2-ABEK14 cells may be useful for high throughput screening to identify inhibitors of CRP synthesis for the prevention of cardiovascular disease.