SIRT3激动剂对乙肝病毒转录和复制的影响

该文探讨了SIRT3激动剂(Honokiol,HKL)对乙肝病毒(Hepatitis B virus,HBV)转录和复制的影响。培养HepG2-NTCP和人原代肝细胞(primary human hepatocytes,PHH),感染HBV颗粒后,用Honokiol(5μmol/L、10μmol/L、20μmol/L)处理细胞后继续培养10天,通过荧光定量PCR检测细胞内HBV DNA、cccDNA和HBV RNAs水平,Southern blot实验进一步检测胞内HBV DNA水平。构建SIRT3-KO细胞,检测敲除SIRT3后,Honokiol对细胞内HBV DNA、cccDNA和HBV RNAs的影响。通过小鼠尾静脉高压注射pCMV-KRAB-Cre质粒和precccDNA质粒构建持续感染小鼠模型,一周后腹腔注射Honokiol持续20天。荧光定量PCR检测小鼠血清中HBV DNA拷贝数,肝组织内HBV DNA、cccDNA和HBV RNAs水平。结果表明,Honokiol浓度依赖性地抑制HepG2-NTCP和PHH细胞内HBV DNA以及HBV RNAs水平,此外,Honokiol可以降低cccDNA的转录活性;敲除SIRT3后,Honokiol不能发挥抗病毒作用;小鼠模型中,Honokiol能够降低血清中HBV DNA和肝组织内HBV DNA拷贝数,以及能够显著抑制肝组织内HBV RNAs水平和cccDNA的转录活性。该研究结果表明,Honokiol能够抑制乙肝病毒转录和复制。     

Formation of covalently closed circular DNA in Hep38.7-Tet cells,a tetracycline inducible hepatitis B virus expression cell line

Hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) plays a central role in chronic HBV infection. However, analysis of the molecular mechanism of cccDNA formation is difficult because of the low efficiency in tissue cultured cells. In this study, we developed a more efficient cccDNA expression cell, Hep38.7-Tet, by subcloning from a tetracycline inducible HBV expression cell, HepAD38. Higher levels of cccDNA were produced in Hep38.7-Tet cells compared to HepAD38 cells. In Hep38.7-Tet cells, the cccDNA was detectable at six days after HBV induction. HBV e antigen (HBeAg) secretion was dependent upon cccDNA production. We screened chemical compounds using Hep38.7-Tet cells and HBeAg secretion as a marker. Most of the hit compounds have already been reported as anti-HBV compounds. These data suggested that Hep38.7-Tet cells will be powerful tools for analysis of the molecular mechanism of cccDNA formation/maintenance and development of novel therapeutic agents to control HBV infection.     

Levels of hepatitis B virus replicative intermediate in serum samples of chronic hepatitis B patients

Hepatitis B virus (HBV) cccDNA levels is an absolute marker of HBV replication in the liver of HBV infected patients. This study aimed to quantify the HBV cccDNA levels in sera and liver tissue samples of treatment naïve patients with chronic hepatitis B. Eighty one chronic hepatitis B (CHB) treatment naïve patients were enrolled from January 2009 to June 2011. Total HBV DNA and HBV cccDNA levels were quantified using sensitive real time PCR assay. The mean age of recruited patients was 34 ± 11.5 years. Fifty four (66.7 %) patients were HBeAg negative. Liver tissue samples were available from 2 HBeAg positive and 21 HBeAg negative CHB patients. The amount of total intrahepatic HBV DNA ranged from 0.09 to 1508.92 copies/cell. The median intrahepatic HBV cccDNA was 0.31 and 0.20 copies/cell in HBeAg positive and HBeAg negative cases, respectively. Serum HBV cccDNA was detectable in 85.2 % HBeAg positive and 48.1 % HBeAg negative CHB patients. Median serum HBV cccDNA was 46,000 and 26,350 copies/mL in HBeAg positive and HBeAg negative subjects, respectively. There was a significant positive correlation between the levels of intrahepatic total HBV DNA and intrahepatic HBV cccDNA (r = 0.533, p = 0.009). A positive correlation was also seen between serum HBV cccDNA levels and serum HBV DNA levels (r = 0.871, p < 0.001). It was concluded that serum HBV cccDNA could be detectable in higher proportion of HBeAg positive patients compared to HBeAg negative patients. Moreover, the median level of serum HBV cccDNA was significantly higher in HBeAg positive patients in contrast to HBeAg negative subjects.     

Clinical stage drugs targeting inhibitor of apoptosis proteins purge episomal Hepatitis B viral genome in preclinical models

A major unmet clinical need is a therapeutic capable of removing hepatitis B virus (HBV) genome from the liver of infected individuals to reduce their risk of developing liver cancer. A strategy to deliver such a therapy could utilize the ability to target and promote apoptosis of infected hepatocytes. Presently there is no clinically relevant strategy that has been shown to effectively remove persistent episomal covalently closed circular HBV DNA (cccDNA) from the nucleus of hepatocytes. We used linearized single genome length HBV DNA of various genotypes to establish a cccDNA-like reservoir in immunocompetent mice and showed that clinical-stage orally administered drugs that antagonize the function of cellular inhibitor of apoptosis proteins can eliminate HBV replication and episomal HBV genome in the liver. Primary human liver organoid models were used to confirm the clinical relevance of these results. This study underscores a clinically tenable strategy for the potential elimination of chronic HBV reservoirs in patients.Subject terms: Target validation, Hepatitis B, Preclinical research, Translational research     

两种抽提乙型肝炎病毒共价闭合环状DNA方法的效果比较

乙型肝炎病毒(hepatitis B virus,HBV)作为一种嗜肝DNA病毒,在感染肝细胞后会在细胞核中形成病毒转录复制的模板和基因储存库--共价闭合环状DNA(covalently closed circular DNA, cccDNA),其持续存在是乙型肝炎慢性化和难以治愈的核心,也是此研究领域内的重点。从细胞样品中稳定抽提获取cccDNA对于保证cccDNA检测的准确性至关重要。Hirt法是一种抽提真核细胞染色体外DNA的方法,被用于HBV cccDNA的抽提,但存在操作复杂和耗时长等问题。为简化操作,有研究对Hirt法进行改良,结合硅胶膜离心柱来抽提染色体外DNA,但尚不清楚该法用于HBV cccDNA抽提与传统Hirt法的效果差异。本研究基于HBV cccDNA细胞转染系统、HBV复制细胞系及感染系统,以DNA印迹(Southern blot)和定量聚合酶链式反应(quantitative polymerase chain reaction, qPCR)作为检测评价手段,平行比较了传统Hirt-酚/氯仿法与改良Hirt-过柱法抽提HBV cccDNA的效果。结果表明,两种方法具有相当的抽提效率和抽提特异性,而改良Hirt-过柱法耗时更短,提示在进行细胞HBV cccDNA抽提时可选择改良Hirt-过柱法以提高实验效率。     

Inhibition of Hepatitis B Virus cccDNA by siRNA in Transgenic Mice

The elimination of viral covalently closed circular DNA (cccDNA) from the nucleus of infected hepatocytes is an obstacle to achieving sustained viral clearance during antiviral therapy of chronic hepatitis B virus (HBV) infection. The aim of our study was to determine whether treatment with siRNA is able to suppress viral cccDNA amplification using a HBV-transgenic mice model. The experimental results revealed that siRNAs can serve as efficient alternative anti-HBV agents, because they showed better inhibitory effect on viral replication and antigen expression in transgenic mice. More importantly, the siRNA markedly inhibited HBV cccDNA amplification.     

乙肝患者肝组织乙型肝炎病毒cccDNA和血清MIF表达的相关性研究

目的:探讨乙肝患者肝组织乙型肝炎病毒(hepatitis B virus,HBV)共价闭合环状DNA(covalently closed circular DNA,cccDNA)和血清巨噬细胞移动抑制因子(Macrophage migration inhibitory factor,MIF)的表达相关性。方法:选择2016年2月到2016年7月在我院诊治的乙肝患者144例作为乙肝组,同期选择体格检查健康者144例作为对照组,采集所有入选者的血清样本,检测血清MIF、谷丙转氨酶(Glutamic pyruvic transaminase,ALT)、谷草转氨酶(Glutamic pyruvic aminotransferase,AST)、总胆红素(total bilirubin,TBIL)的表达,并对乙肝组患者肝组织HBV cccDNA采用荧光定量PCR技术检测表达分析,直线相关分析乙肝组的血清HBV cccDNA表达量与血清ALT、TBi L、AST、MIF含量相关性。结果:乙肝组的血清MIF、ALT、TBi L、AST含量均明显高于对照组(P0.05)。乙肝组的肝组织HBV cccDNA阳性率为54.17%(78/144)。直线相关分析显示乙肝组的肝组织HBV cccDNA表达量与血清ALT、TBi L、AST、MIF含量均呈现明显正相关性(P0.05)。结论:乙肝患者体内血清MIF水平明显升高,伴肝组织HBV cccDNA的表达也升高,两者存在明显的正相关性。因此检测血清MIF水平有助于评估乙肝患者HBV的感染情况。     

Effects of Entecavir on Hepatitis B Virus Covalently Closed Circular DNA in Hepatitis B e Antigen-Positive Patients with Hepatitis B

The aim of this study was to assess the effect of 48-week entecavir therapy on serum and intrahepatic hepatitis B virus, covalently closed circular DNA (HBV cccDNA) levels in hepatitis B e antigen (HBeAg)-positive patients. A total of 120 patients with HBeAg-positive chronic hepatitis were treated with entecavir for 48 weeks. Serum HBV markers, total HBV DNA, and HBV cccDNA levels were measured at baseline and week 48. Biopsies from 20 patients were available for both intrahepatic total HBV DNA and cccDNA testing at these timepoints. HBV cccDNA levels were decreased from a median level of 5.1×10⁶ copies/mL at baseline to a median level of 2.4×10³ copies/mL at week 48. Reduction magnitudes of HBV cccDNA in patients with normalized alanine aminotransferase levels and those undergoing HBeAg seroconversion were significantly greater than those in alanine aminotransferase-abnormal and HBeAg positive patients. Intrahepatic HBV cccDNA was decreased significantly after 48 weeks of treatment, but could not be eradicated. In conclusion, treatment of HBeAg-positive hepatitis B patients with entecavir for 48 weeks decreased serum and intrahepatic HBV cccDNA significantly, and the magnitude of HBV cccDNA reduction was related to total HBV DNA decrease, alanine aminotransferase normalization, and HBeAg seroconversion.