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ABSTRACT: Entecavir rescue therapy is frequently used in patients with lamivudine-resistant hepatitis B virus (HBV) strains. The aim of this study was to investigate evolutionary patterns of HBV quasispecies during entecavir rescue therapy and evaluate their impacts on therapeutic efficacy. We enrolled 21 chronic hepatitis B patients who failed to respond to lamivudine therapy and were switched to entecavir treatment. Measurement of serum HBV DNA and sequence analysis of HBV reverse transcriptase were done up to 144 weeks. Four patients of this series showed a reversion to wild-type HBV after entecavir treatment and in three of them, a complete viral response (<2.6 log10 copies/ml) was achieved. An additional five patients developed entecavir genotypic resistance, with prior occurrence of lamivudine-resistant mutation (L180 M ± M204 V/I). A viral breakthrough was observed in four of the five patients with entecavir-resistant mutants. The remaining 12 patients of this series showed dominance of lamivudine-resistant mutants throughout the entecavir rescue therapy, and five of them achieved a complete viral response at the end of follow-up. The average HBV DNA level was significantly lower in patients with a reversion to wild-type HBV than in those without it (P < 0.05). In conclusion, reversion to wild-type HBV is a favorable indicator for response to entecavir rescue therapy in lamivudine-refractory patients with chronic hepatitis B. The presence of lamivudine-resistant mutations contributes to the development of entecavir resistance.
Virus Genes 04/2013; · 1.85 Impact Factor
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Jie-li Hu,
Jing Cui, Jin-jun Guo,
Wen-lu Zhang,
Xue-fei Cai,
Zuo-wei Yuan,
Qing-ling Li,
Xiao-yan Deng,
Ai-zhong Zeng,
Yuan Hu,
Ni Tang,
Ai-long Huang
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ABSTRACT: Phenotypic assays of hepatitis B virus (HBV) play an important role in research related to the problem of drug resistance that emerges during long-term nucleot(s)ide therapy in patients with chronic hepatitis B. Most of the phenotypic assay systems that are available currently rely on the transfection of recombinant replication-competent HBV DNA into hepatoma cell lines. Cloning clinical HBV isolates using conventional digestion-and-ligation techniques to generate replication-competent recombinants can be very difficult because of the sequence heterogeneity and unique structure of the HBV genome. In this study, a new strategy for constructing an HBV 1.1× recombinant was developed. The core of this strategy is the "fragment substitution reaction" (FSR). FSR allows PCR fragments to be cloned without digestion or ligation, providing a new tool for cloning fragments or genomes amplified from serum HBV DNA, and therefore making the assay of HBV phenotypes more convenient. Using this strategy, a phenotypic assay was performed on an HBV strain carrying an rtS246T variant isolated from a patient with chronic hepatitis B that was only responsive partially to entecavir therapy. The results indicated that this strain is sensitive to entecavir in vitro.
Journal of Medical Virology 11/2011; 84(1):34-43. · 2.82 Impact Factor
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Yao Zhao,
Xiu-Yu Zhang,
Yuan Hu,
Wen-Lu Zhang,
Jie-Li Hu,
Ai-Zhong Zeng, Jin-Jun Guo,
Wen-Xiang Huang,
Wei-Xian Chen,
You-Lan Shan,
Ai-Long Huang
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ABSTRACT: We compared a novel real-time genotyping and quantitative PCR (GQ-PCR) assay, direct sequence analysis, reverse hybridization, and multiplex PCR for genotyping hepatitis B virus (HBV) in 127 HBV-infected patients. We found that GQ-PCR had the highest concordance with sequence analysis and the highest detection rate for mixed genotype detecting.
Journal of clinical microbiology 07/2011; 49(9):3392-4. · 4.16 Impact Factor
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ABSTRACT: To investigate the evolution of hepatitis B virus (HBV) quasispecies in one patient during lamivudine (LAM) monotherapy and switching to entecavir (ETV) rescue treatment.
Serum samples were taken at seven different time points during antiviral therapy (0, 24, 48, 60, 72, 96, 152 weeks, respectively), the HBV DNA polymerase gene was amplified, cloned and sequenced to analyze the amino acid substitutions within HBV DNA polymerase gene and distribution of virus quasispecies. Quantitative detection of the HBV wild strains and total virus was performed by amplification refractory mutation system real-time PCR (ARMS-PCR).
Three mutation patterns detected during antiviral therapy in the patient: rtM204V, rtM204V+rtL180M and rtM204I. The HBV quasispecies were found always in dynamic variation. The HBV populations were completely replaced with the LAM-resistant variants when the viral breakthrough was encountered during LAM monotherapy. Interestingly, the wild-type variants presented gradually dominant (79.3%) with the decline of HBV DNA load after switching to ETV rescue administration. ARMS-PCR results showed that the wild-type variants account ed for 68.55% of the HBV populations at baseline and this proportion declined to 0.21% when the viral breakthrough emerged under LAM therapy. The wild-type variants gradually increased from week 24 after switching to ETV rescue therapy and the proportion of HBV wild-type variants in the population fluctuated between 16.01% to 26.93%.
The distribution of virus quasispecies were always in dynamic variation during sequential therapy with nucleotide analogs in chronic hepatitis B patients. Different patterns of dynamic HBV quasispecies may have different contribution in ETV resistance in LMV refractory patients with ETV administration.
Zhonghua gan zang bing za zhi = Zhonghua ganzangbing zazhi = Chinese journal of hepatology 07/2011; 19(7):516-20.
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ABSTRACT: Hepatitis B virus (HBV) is an important cause of human chronic liver diseases and is a major public health problem. Viral load and HBV genotype play critical roles in determining clinical outcomes and response to antiviral treatment in hepatitis B patients. Viral genotype detection and quantification assays are currently in use with different levels of effectiveness. In this study, the performance of a real-time genotyping and quantitative PCR (GQ-PCR)-based assay was evaluated. Through the use of genotype-specific primers and probes, this assay provides simultaneous identification and quantification of genotypes B and C in a single reaction. Our GQ-PCR correctly identified all predefined genotypes B and C, and no cross-reaction between genotypes B and C were observed. The GQ-PCR identified more cases of HBV infections with mixed genotypes B and C than direct sequencing did. Samples from 127 HBV-infected Chinese patients were genotyped with GQ-PCR, revealing 56.7% HBV as genotype B, 13.4% as genotype C, and 29.8% as mixed genotypes B and C. This assay provides a reliable, efficient, and cost-effective means for quantification of the B and C genotypes of HBV in single or mixed infections. This assay is suitable for sequential monitoring of viral load levels and for determining the relationship between the genotype viral load and stage of disease in Asians.
Journal of clinical microbiology 10/2010; 48(10):3690-7. · 4.16 Impact Factor
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ABSTRACT: To explore the mechanism for adefovir dipivoxil (ADV) resistance occurred in chronic hepatitis B patients of a series of phase III clinical trails.
30 resistant HBV strains were selected out from 177 cases of ADV treated chronic hepatitis B patients. HBV polymerase RT region were amplified by nested PCR and analyzed with the standard nucleotide sequence of HBV strains deposited in GeneBank.
21 out of 30 HBV strains were primary resistant strains, among them 5 HBV strains (23.8%, 5/21) had the polymorphism site of rtN118H. While the other 9 HBV strains showed secondary resistance, variations in conservative region C (rtM207V) and other non-conservative regions were found. The classic mutation sites such as rtN236T and rtA181V/T were not found.
Polymorphism site of rtN118H might be responsible for HBV primary resistance to ADV therapy. rtM207V variation in HBV RT C domain and other variation sites might play a role in HBV secondary resistance to ADV treatment, and natural resistant quasispecies may be the basis for the ADV quick resistance. These conclusions await further confirmation by phenotype test.
Zhonghua gan zang bing za zhi = Zhonghua ganzangbing zazhi = Chinese journal of hepatology 10/2009; 17(10):730-4.
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ABSTRACT: In the absence of a robust infectable cell culture system, assays related to replication of clinical HBV isolates are based on the transfection of replication-competent HBV DNA into hepatoma cell lines that are able to replicate and secrete HBV virions. Current methods for constructing HBV 1.1 genomes work well for drug susceptibility assays, but are not very suitable for research on HBV replication capacity or regulation since a heterogeneous promoter is required to drive pgRNA transcription. A new strategy for constructing HBV 1.3 genomes that contain HBV intrinsic promoter necessary for pgRNA transcription is reported in this paper. Using this strategy, three HBV 1.3 genomes from isolates of three patients were constructed. When the three HBV 1.3 genomes were transfected into the HepG2 cell line, replicative intermediates were detectable by Southern blotting with digoxigenin-labeled DNA probe in two of the three constructs. Using overlap extension PCR and avoiding as much as possible the digestion-and-ligation process, this strategy could be applied to constructing longer-than-genome units for most genotypes of HBV strains.
Journal of virological methods 06/2009; 161(1):63-9. · 2.13 Impact Factor
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ABSTRACT: Osmotic Response Element-Binding Protein (OREBP), also known as TonEBP or NFAT5, is a unique transcription factor. It is hitherto the only known mammalian transcription factor that regulates hypertonic stress-induced gene transcription. In addition, unlike other monomeric members of the NFAT family, OREBP exists as a homodimer and it is the only transcription factor known to bind naked DNA targets by complete encirclement in vitro. Nevertheless, how OREBP interacts with target DNA, also known as ORE/TonE, and how it elicits gene transcription in vivo, remains unknown.
Using hypertonic induction of the aldose reductase (AR) gene activation as a model, we showed that OREs contained dynamic nucleosomes. Hypertonic stress induced a rapid and reversible loss of nucleosome(s) around the OREs. The loss of nucleosome(s) was found to be initiated by an OREBP-independent mechanism, but was significantly potentiated in the presence of OREBP. Furthermore, hypertonic induction of AR gene was associated with an OREBP-dependent hyperacetylation of histones that spanned the 5' upstream sequences and at least some exons of the gene. Nevertheless, nucleosome loss was not regulated by the acetylation status of histone.
Our findings offer novel insights into the mechanism of OREBP-dependent transcriptional regulation and provide a basis for understanding how histone eviction and transcription factor recruitment are coupled.
PLoS ONE 01/2009; 4(12):e8435. · 4.09 Impact Factor
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ABSTRACT: It is well known that different genotypes of hepatitis B virus (HBV) have a different sensitivity to interferon-alpha or lamivudine (nucleoside analogue) antiviral therapy. However, for adefovir dipivoxil (ADV, a nucleotide analogue), the antiviral response of the different genotypes remains to be clarified. In order to evaluate the response of HBV genotypes to ADV therapy and to identify factors that might affect initial virological response, we performed a retrospective analysis on patients with chronic hepatitis B (CHB) in Chinese Han population. The study included 183 patients, who had been tested positive for hepatitis B e antigen (HBeAg) and had been treated with ADV (10 mg/day) for 48 weeks. The numbers of patients infected with HBV genotype B and genotype C were 98 and 75 cases, respectively, and the remaining 10 patients were mixture infection of genotypes B plus C or genotypes B plus D. The mean HBV-DNA reduction and HBV-DNA seroclearance of genotypes B and C at 48 weeks were 3.6 log(10) and 3.1 log(10) copies/ml (p < 0.05) and 41.8% and 34.6% (p < 0.05), respectively. There were no statistically significant differences between genotypes B and C in terms of HBeAg loss, anti-HBe seroconversion and normalization of serum alanine aminotransferase (ALT). Multivariate analysis showed that young age, low pretreatment HBV-DNA and/or elevated ALT level might be independent predictive factors associated with initial virological response. Thus, in Han CHB patients who are HBeAg-positive, HBV genotype B shows a better virological response to ADV therapy than does genotype C.
The Tohoku Journal of Experimental Medicine 12/2008; 216(3):205-11. · 1.24 Impact Factor
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ABSTRACT: The genotypic evolution of HBV quasi-species was analyzed in a nucleoside/nucleotide-naïve patient who developed resistance to entecavir. The lamivudine resistant quasi-species (rtM204V+/-rtL180M), absent at baseline, were emerged as early as 48 weeks after entecavir administration. Entecavir-resistant quasi-species (rtM204V+/-rtL180M plus S202G) were found after week 112 and gradually became the predominant mutations afterwards. The lamivudine- and entecavir-resistant mutations emerged closely in combination with the rtV207L, rtA222T, rtP237T or rtI163V substitutions. Our results indicated that the lamivudine-resistant mutations were developed first and may serve as a prequisite for subsequent entecavir-resistant mutations in this nucleoside/nucleotide-naïve patient.
Antiviral research 11/2008; 81(2):180-3. · 3.61 Impact Factor
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Ai-zhong Zeng,
Hui Deng,
Feng-ying Peng,
Xiao-juan Xin,
Chun Yang,
Qing-ling Li, Jin-jun Guo,
Zhen-zhen Zhang,
Mei-jun Hao,
Zhe Yuan,
Wen-xiang Huang,
Ai-long Huang
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ABSTRACT: To investigate the role of HBV genotypes on their response to adefovir dipivoxil (ADV) antiviral therapy.
HBV genotypes from 177 HBeAg-positive chronic hepatitis B (CHB) patients were identified and the patients were treated with ADV 10 mg per day for 48 weeks. The clinical data in terms of serum HBV DNA seroclearance, mean HBV DNA reduction (log value), HBeAg loss, anti-HBe seroconversion and serum ALT of those patients were analyzed against their HBV genotypes.
Genotype B and genotype C were found in 102 and 65 cases, respectively. The mean HBV DNA reduction in patients with genotype B and genotype C at their treatment times of 12, 24 and 48 weeks was 2.2 log10copies/ml, 2.1 log10copies/ml (P more than 0.05), 2.7 log10copies/ml, 2.4 log10copies/ml (P more than 0.05) and 3.6 log10copies/ml, 3.1 log10copies/ml (P less than 0.05), respectively. At the end of the therapy (48 weeks), 43 (42.2%) patients with genotype B HBV infection and 22 (33.8%) patients with genotype C HBV infection had achieved HBV DNA seroclearance (P less than 0.05).
Our results suggest that genotype B HBV has a better virological response to ADV therapy in HBeAg-positive chronic hepatitis B patients than that of genotype C. Longer terms of ADV treatment are needed to confirm this conclusion.
Zhonghua gan zang bing za zhi = Zhonghua ganzangbing zazhi = Chinese journal of hepatology 07/2008; 16(6):412-5.
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ABSTRACT: To establish a set of suitable and reliable methods for HBV genotyping and to study the distribution of HBV genotypes.
Type-specific nucleotides were searched through alignment of S genes (more than 1000 sequences) listed in GenBank. Then, type-specific primers were designed and type-specific primer PCR was used to genotype the 238 HBV strains. S genes of the untyped strains were further amplified and sequenced to find out their genotypes with type-specific nucleotide analysis.
All the 238 HBV strains were genotyped. 159 (66.8%) cases were genotype B, 69 (28.9%) were genotype C, 6 (2.5%) were mixtures of genotypes B and C and 4 (1.6%) were mixtures of genotypes B and D. No genotypes of A, E, F, G, and H were found.
Genotypes B and C are the most common types for HBV strains. Mixtures of genotypes B and C or genotypes B and D coinfection rarely existed. There is no relationship between the gender of the patients and HBV genotypes (X2 = 0.794, P more than 0.05).
Zhonghua gan zang bing za zhi = Zhonghua ganzangbing zazhi = Chinese journal of hepatology 03/2008; 16(2):84-7.
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ABSTRACT: Histone deacetylase (HDAC) activity is commonly associated with transcriptional repression. However, there is also evidence for a function in transcriptional activation. Previous studies have demonstrated a fundamental role of deacetylase activity in IFNa-responsive gene transcription. In the case of type II IFN (IFNgamma) results are controversial: some genes require HDAC activity, while transcription of others is repressed by HDAC. To investigate the effect of HDAC on transcription of an IFNgamma-activated gene, real-time PCR was used to measure CXCL10 mRNA in Hela cells stimulated with IFNgamma in the presence or absence of the HDAC inhibitor TSA. Chromatin imunoprecipitation combined with real-time PCR was used to check acetylation of histone H4 and recruitment of the STAT1 complex to the ISRE locus of the CXCL10 gene. Activation of CXCL10 transcription in response to IFNgamma was paralleled by a decrease in histone H4 acetylation and an increase in recruitment of the STAT1 complex to the CXCL10 ISRE locus. The transcription of CXCL10 and histone H4 deacetylation were blocked by TSA, but the latter had no obvious affect on recruitment of the STAT1 complex. Our data indicate that IFNgamma and STAT-dependent gene transcription requires the participation of HDAC, as does the IFNalpha-STAT pathway.
Molecules and Cells 11/2006; 22(2):163-7. · 2.18 Impact Factor
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ABSTRACT: The osmotic response element-binding protein (OREBP), also known as tonicity enhancer-binding protein (TonEBP) or NFAT5, regulates the hypertonicity-induced expression of a battery of genes crucial for the adaptation of mammalian cells to extracellular hypertonic stress. The activity of OREBP/TonEBP is regulated at multiple levels, including nucleocytoplasmic trafficking. OREBP/TonEBP protein can be detected in both the cytoplasm and nucleus under isotonic conditions, although it accumulates exclusively in the nucleus or cytoplasm when subjected to hypertonic or hypotonic challenges, respectively. Using immunocytochemistry and green fluorescent protein fusions, the protein domains that determine its subcellular localization were identified and characterized. We found that OREBP/TonEBP nuclear import is regulated by a nuclear localization signal. However, under isotonic conditions, nuclear export of OREBP/TonEBP is mediated by a CRM1-dependent, leucine-rich canonical nuclear export sequence (NES) located in the N terminus. Disruption of NES by site-directed mutagenesis yielded a mutant OREBP/TonEBP protein that accumulated in the nucleus under isotonic conditions but remained a target for hypotonicity-induced nuclear export. More importantly, a putative auxiliary export domain distal to the NES was identified. Disruption of the auxiliary export domain alone is sufficient to abolish the nuclear export of OREBP/TonEBP induced by hypotonicity. By using bimolecular fluorescence complementation assay, we showed that CRM1 interacts with OREBP/TonEBP, but not with a mutant protein deficient in NES. Our findings provide insight into how nucleocytoplasmic trafficking of OREBP/TonEBP is regulated by changes in extracellular tonicity.
Journal of Biological Chemistry 09/2006; 281(33):23870-9. · 4.77 Impact Factor
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ABSTRACT: To study the role of histone modification in the regulation of IFN-gamma-activated gene using chromatin immunoprecipitation technique.
Real-time PCR was used to measure the mRNA level of interferon-gamma-inducible protein 10 (IP-10) in Hela cells. Chromatin immunoprecipitation combined with Real-time PCR was used to check the histone H4 acetylation level at IFN-stimulated response element (ISRE) locus of IP-10 gene.
IP-10 was strongly activated by IFN-gamma. The histone H4 deacetylation happened at the ISRE locus when IP-10 was induced by IFN-gamma. The activation of IP-10 and the deacetylation of histone H4 at the ISRE site induced by IFN-gamma were inhibited or blocked by histone deacetylase (HDAC) inhibitor trichostatin A (TSA).
The histone H4 deacetylation at the ISRE site is related with the activation of IP-10 by IFN-gamma.
Zhonghua gan zang bing za zhi = Zhonghua ganzangbing zazhi = Chinese journal of hepatology 08/2006; 14(7):525-8.
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ABSTRACT: To synthesize highly pure HBV post-transcriptional regulatory element (HPRE) via transcription in vitro by T7 RNA polymerase.
HPRE gene was amplified by PCR from a template containing HBV complete genomic DNA and cloned into plasmid pGEM-11zf. The cloned DNA sequence was transcribed by T7 RNA polymerase.
The construction of HPRE gene recombinant plasmid and production of HPRE via transcription in vitro was successful.
In vitro transcription by T7 RNA polymerase can be used to synthesize highly pure HPRE.
Zhonghua gan zang bing za zhi = Zhonghua ganzangbing zazhi = Chinese journal of hepatology 12/2005; 13(11):808-10.
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ABSTRACT: To develop a new method for amplifying and sequencing the full-length of HBV genome.
A pair of primers located at the nick region of HBV molecule and a thermostable polymerase with high fidelity and sensitivity were used. After cloning the PCR products into a plasmid, the sequences of HBV genome were analyzed.
The full-length of HBV genome were acquired using this method. The sensitivity and fidelity of the new method were also analyzed. The least quantity of initial templates was 10(2) and the artificial mutation rate was 1.2 bp/kb.
This method can be used in amplification and sequence analysis of the full-length of HBV genome on a large scale.
Zhonghua gan zang bing za zhi = Zhonghua ganzangbing zazhi = Chinese journal of hepatology 10/2003; 11(10):592-4.
