Inhibition of histone deacetylases prevents cytokine-induced toxicity in beta cells
Inhibition of histone deacetylases prevents cytokine-induced toxicity in beta cells
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DOI：
10.1007/s00125-006-0562-3
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发表时间：
2007-04-01
期刊：
影响因子：
8.2
通讯作者：
Mandrup-Poulsen, T.
中科院分区：
文献类型：
--
作者：
Larsen, L.;Tonnesen, M.;Mandrup-Poulsen, T.
1型糖尿病患者胰岛β细胞的免疫清除涉及IL-1β和干扰素等细胞毒性细胞因子的释放，这些细胞因子在体外通过依赖和非依赖一氧化氮(NO)的机制诱导胰岛β细胞死亡。核因子kappaB是炎症反应中的重要信号分子，是诱导型一氧化氮合酶(INOS)基因和促凋亡基因表达所必需的。核因子kappaB最近被证明与染色质修饰酶、组蛋白乙酰转移酶和组蛋白脱乙酰酶(HDAC)有关，并且在一些炎症性疾病中已获得抑制HDAC的积极作用。因此，本研究的目的是研究HDAC抑制是否能保护β细胞免受细胞因子诱导的毒性。在没有或存在IL-1β和干扰素-γ的情况下，用HDAC抑制剂Suberoylanilde异羟肟酸或曲古抑素A预先培养β细胞系INS-1或完整的大鼠胰岛。分别用酶联免疫吸附试验和Griess试剂检测对胰岛素分泌和NO生成的影响。免疫印迹法检测iNOS水平，免疫印迹结合凝胶迁移率改变分析法检测核因子-kappaB活性。用3-(4，5-dimethyldiazol-2-yl)-2，5-diphenyl-tetrazolium溴化法检测细胞存活率，用末端脱氧核苷酸转移酶介导的dUTP缺口末端标记法和组蛋白-DNA复合体ELISA法检测细胞的凋亡率。IL-1β诱导抑制蛋白kappa Bα(I kappa Bα)的双相磷酸化，第二个峰对HDAC抑制敏感。HDAC抑制可阻止细胞因子诱导的β细胞凋亡和与核因子kappa B反式激活活性下调相关的β细胞功能受损。
The immune-mediated elimination of pancreatic beta cells in type 1 diabetes involves release of cytotoxic cytokines such as IL-1 beta and IFN gamma, which induce beta cell death in vitro by mechanisms that are both dependent and independent of nitric oxide (NO). Nuclear factor kappa B (NF kappa B) is a critical signalling molecule in inflammation and is required for expression of the gene encoding inducible NO synthase (iNOS) and of pro-apoptotic genes. NF kappa B has recently been shown to associate with chromatin-modifying enzymes histone acetyltransferases and histone deacetylases (HDAC), and positive effects of HDAC inhibition have been obtained in several inflammatory diseases. Thus, the aim of this study was to investigate whether HDAC inhibition protects beta cells against cytokine-induced toxicity.The beta cell line, INS-1, or intact rat islets were precultured with HDAC inhibitors suberoylanilide hydroxamic acid or trichostatin A in the absence or presence of IL-1 beta and IFN gamma. Effects on insulin secretion and NO formation were measured by ELISA and Griess reagent, respectively. iNOS levels and NF kappa B activity were measured by immunoblotting and by immunoblotting combined with electrophoretic mobility shift assay, respectively. Viability was analysed by 3-(4,5-dimethyldiazol-2-yl)-2,5-diphenyl-tetrazolium bromide and apoptosis by terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) assay and histone-DNA complex ELISA.HDAC inhibition reduced cytokine-mediated decrease in insulin secretion and increase in iNOS levels, NO formation and apoptosis. IL-1 beta induced a bi-phasic phosphorylation of inhibitor protein kappa B alpha (I kappa B alpha) with the 2nd peak being sensitive to HDAC inhibition. No effect was seen on I kappa B alpha degradation and NF kappa B DNA binding.HDAC inhibition prevents cytokine-induced beta cell apoptosis and impaired beta cell function associated with a downregulation of NF kappa B transactivating activity.