NTZ(硝唑尼特)的治疗HBV的机理研究

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以下内容节选自
Nitazoxanide, tizoxanide and other thiazolides are potent inhibitors of hepatitis B virus and hepatitis C virus replication...

There were 4 presentations at EASL. I'll be reporting them to you in detail.

Antiviral Research
Volume 77, Issue 1, January 2008, Pages 56-63

Hepatitis B virus (HBV)

Activities of compounds and combinations in 2.2.15 cell cultures

NTZ and its active metabolite, TIZ, exhibited selective inhibition of intracellular HBV replication and extracellular virus production by 2.2.15 cells (Table 1). Several other thiazolides (see Table 1) were also effective inhibitors of HBV replication in this assay system. Combinations of NTZ with either of two drugs licensed for anti-HBV therapy, lamivudine and adefovir dipovoxil, demonstrated synergistic interactions when used to treat 2.2.15 cells (Table 1, Fig. 2A and B). The anti-HBV assays were conducted under confluence as this provides the conditions for optimal HBV replication (Sells et al., 1988; Korba and Gerin, 1992). While under the conditions of the antiviral assay NTZ displayed minimal cytotoxicity (>100uM, Table 1), cytotoxicity of NTZ in rapidly dividing cultures of 2.2.15 cells was higher (20?.3uM). NTZ and RM4850 were effective inhibitors of several HBV LMV-resistant and one ADV-resistant constructs in transient transfection assays in Huh7 cells (Table 2). No significant differences in potency of these thiazolides relative to that observed for wild-type HBV were observed for any of the drug-resistant viruses tested.

Effect of NTZ on production of HBV proteins

Unlike most viruses (including HCV), HBV RNA transcription and protein production are effectively separated from viral genome replication due to the presence of a long-lived population of covalently closed viral template genomes in the host cell nucleus (cccDNA) (see Locarnini, 2004 for a review). Intracellular HBV replication takes place in viral nucleocapsids located in the cytoplasm. As a result, most compounds that inhibit HBV DNA replication (e.g. nucleoside analogues), do not typically alter HBV protein production, especially in cell culture. Suspecting a novel mechanism of action of NTZ against HBV, we conducted studies to determine if the drug inhibited the production of major HBV proteins. As assessed by semiquantitative EIA, NTZ reduced the levels of extracellular HBV surface and e antigens (HBsAg, HBeAg), as well as the levels of intracellular HBV nucleocapsid core antigen (HBcAg) in a dose-dependent manner (Table 3, Fig. 3). The potency of NTZ against HBsAg and HBeAg was similar to that observed against HBV virion production in the same experiment. The relative potency of NTZ against intracellular HBcAg was similar to that observed for the inhibition of intracellular HBV DNA replication. No quantitative interference with the ability of the EIAs to detect HBV proteins was observed in samples from control cultures to which 10 uMNTZ was added (data not shown).

NTZ did not induce a reduction in intracellular HBV RNA as assessed by Northern blot hybridization (Table 3, Fig. 3). In the same experiment, LMV did not affect the levels of HBV proteins or HBV RNA despite inducing significant reductions in HBV virion production and intracellular HBV DNA replication (Table 3).



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化合物和组合活动在2.2.15细胞培养
  
硝唑尼特NTZ及其活性代谢物TIZ，展现出2.2.15细胞（表1）细胞内乙型肝炎病毒复制和细胞外的生产选择性抑制。几个（其他thiazolides见表1）这也有效地检测乙肝病毒的复制系统抑制剂。将NTZ和其他两种药物组合治疗乙肝病毒，拉米夫定和阿德福韦酯，使用时表现出治疗2.2.15细胞（表1，图。第2A和B）的协同作用。抗乙肝病毒试剂汇合下进行，因为这提供了最佳的乙肝病毒复制（Sells 等，1988;戈尔巴和日兰，1992年）。而根据测定的抗病毒药物，硝唑尼特显示出最小的细胞毒性（> 100uM，表1），在快速分裂的细胞毒性，硝唑尼特2.2.15细胞培养较高（20？0.3微米）。硝唑尼特和RM4850是几个乙肝LMV耐药和ADV耐药结构在一个腺性在Huh7细胞（表2）瞬时转染实验构建有效的抑制剂。对野生型HBV的对抗药性病毒任何观察测试观察中,在这些thiazolides效力相对无显着差异。
  
对硝唑尼特对乙肝病毒蛋白的产生
  
与大多数病毒（包括丙型肝炎），乙肝病毒RNA的转录和蛋白质的生产得到有效的病毒基因组复制分离由于长期居住人口的存在共价闭合模板病毒在宿主细胞核（cccDNA的）基因组（见Locarnini，2004）。细胞内乙型肝炎病毒复制发生在位于细胞质中的病毒核衣壳的地方。因此，大多数化合物能抑制乙肝病毒DNA的复制（如核苷类似物），通常不会改变，特别是乙肝病毒蛋白在细胞培养生产。我们对硝唑尼特抑制乙肝病毒的新机制进行了研究，以确定该药物抑制乙肝病毒的主要蛋白质的生产过程。正如半定量评估环境影响评估，硝唑尼特降低细胞外乙肝病毒表面抗原和e抗原的水平（乙肝表面抗原，e抗原），以及以剂量相关性降低细胞内乙型肝炎病毒的核心抗原水平（HBcAg）（表3，图。3 ）。对硝唑尼特对HBsAg和HBeAg的作用和对乙肝病毒颗粒复制中观察到同样作用相似。对细胞内的硝唑尼特对HBcAg的作用和观察到的对于细胞内HBV DNA复制的抑制作用相似。用酶免疫测定法的定量检测乙型肝炎病毒蛋白，观察到从控制模式到10个样本uMNTZ增加（数据未显示）没有定量干扰。
  
硝唑尼特不诱导细胞内乙型肝炎病毒核糖核酸减少由北方杂交评估（表3，图。3）。在同样的实验，尽管不影响LMV诱导细胞内乙型肝炎病毒粒子的生产和乙肝病毒DNA的复制（表3）显着降低乙肝病毒蛋白质或RNA的乙肝病毒的水平。

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谢谢楼主的最新报道 ！

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好像说肖对于细胞内部的ccd-dna无效，但是对于在细胞表面的表面抗体啦什么的有抑制作用，与核苷类有协同作用
如果能降低表面抗原达到免疫激活也不错的