The A1762T/G1764A mutations enhance HBV replication by alternating viral transcriptome.

The A1762T/G1764A mutations, one of the most common mutations in the hepatitis B virus basal core promoter, are associated with the progression of chronic HBV infection. However, effects of these mutations on HBV replication remains controversial. This study aimed to systematically investigate the effect of the mutations on HBV replication and its underlying mechanisms. Using the prcccDNA/pCMV-Cre recombinant plasmid system, a prcccDNA-A1762T/G1764A mutant plasmid was constructed. Compared with wild-type HBV, A1762T/G1764A mutant HBV showed enhanced replication ability with higher secreted HBV DNA and RNA levels, while Southern and Northern blot indicated higher intracellular levels of relaxed circular DNA, single-stranded DNA, and 3.5 kb RNA. Meanwhile, the mutations increased expression of intracellular core protein and decreased the production of HBeAg and HBsAg. In vitro infection based on HepG2-NTCP cells and mice hydrodynamic injection experiment also proved that these mutations promote HBV replication. 5'-RACE assays showed that these mutations upregulated transcription of pregenomic RNA (pgRNA) while downregulating that of preC RNA, which was further confirmed by full-length transcriptome sequencing. Moreover, a proportion of sub-pgRNAs with the potential to express polymerase were also upregulated by these mutations. The ChIP-qPCR assay showed that A1762T/G1764A mutations created a functional HNF1α binding site in the BCP region, and its overexpression enhanced the effect of A1762T/G1764A mutations on HBV. Our findings revealed the mechanism and importance of A1762T/G1764A mutations as an indicator for management of CHB patients, and provided HNF1α as a new target for curing HBV-infected patients.

Nucleos(t)ide analogues altered quasispecies composition of hepatitis B virus (HBV)-resistant mutations in serum HBV DNA and serum HBV RNA.

Serum hepatitis B virus (HBV) RNA is a new serological indicator reflecting viral replication with good clinical application prospects. This study aimed to clarify the dynamic changes of serum HBV RNA levels and the quasispecies of HBV RNA virus-like particles in nucleos(t)ide analogues (NAs)-experienced chronic hepatitis B (CHB) patients harboring NAs-resistant mutations and their identifiable effects on NAs resistance. We included CHB patients who were on long-term NAs treatment and with HBV DNA rebound. The longitudinally dynamics of serum HBV RNA levels were quantitatively detected, and the quasispecies differences between serum HBV DNA and serum HBV RNA were compared by high-throughput sequencing. The effect of NAs concentration pressure on altering the resistance mutations quasispecies proportion of HBV DNA and HBV RNA in cell supernatant was analyzed in vitro. A total of 447 serum samples from 36 CHB patients treated with NAs were collected. The median follow-up period was 47 months (about 4 years), and the longest follow-up period was 117 months (about 10 years). Our results showed that HBV RNA could reflect virological breakthrough in 23 (64%, 23/36) patients, and serum HBV RNA rebound earlier than HBV DNA in 12 (52%, 12/23) patients. However, serum HBV RNA remained at a consistently high level and did not fluctuate significantly with the HBV DNA rebound in 6 of 36 patients. In addition, serum HBV RNA was not consistently detectable in 7 of the 36 patients, and their serum HBV RNA was undetectable even after HBV DNA had rebounded. The proportion of drug-resistant mutations in HBV DNA was higher than that of HBV RNA by high-throughput sequencing. The results of in vitro experiments showed that the viral strains with drug-resistant mutation in HBV DNA in cell supernatants gradually become the dominant strains with the increase of NAs concentrations. Serum HBV RNA levels can reflect virological breakthrough in most NAs- treated CHB patients, but there are certain limitations. NAs alter the quasispecies composition of serum HBV DNA and serum HBV RNA, resulting in a higher detection rate of drug-resistant mutations in serum HBV DNA than in serum HBV RNA.

Levels of HBV RNA in chronic HBV infected patients during first-line nucleos(t)ide analogues therapy.

BACKGROUND: Serum HBV RNA has been considered a potential biomarker in monitoring the prognosis of chronic hepatitis B (CHB). However, Real-life cohort studies on the profile of HBV RNA in chronic HBV infected patients during first-line nucleos(t)ide analogues (NAs) are lacking. We aimed to investigate HBV RNA dynamic pattern and clinical value chronic HBV infected patients under NA therapy. METHODS: HBV RNA and clinical assessments were measured in 82 treatment-naïve chronic HBV infected patients. These enrolled patients were categorized into HBeAg-positive chronic HBV infected (n = 53) and HBeAg-negative chronic HBV infected (n = 29). Of these, there were 59, 46, and 30 chronic HBV infected patients completed the follow-up clinical assessments at 12, 24, and 48 weeks of NAs therapy, respectively. RESULTS: In treatment-naïve patients, there was a positive correlation between HBV RNA and HBV DNA, HBsAg (r = 0.602 and 0.502. P < 0.05). The median level of HBV DNA was higher than HBV RNA by 1.64 log10 copies/mL. The mean level of serum HBV RNA was 4.62 (IQR: 3.05-5.82) log10 copies/mL at baseline, and the median level of HBV RNA was 2.88 (IQR: 0-4.67), 2.71 (IQR: 0-4.22), and 2.96 (IQR: 0-4.32) log10 copies/mL at week 12, 24, and 48, respectively. HBV RNA showed a positive linear correlation with HBV DNA at 12, 24, and 48 weeks of NA treatment (r = 0.640, 0.715, and 0.656 respectively, P < 0.05). In patients who were treated 48 weeks NAs, 67% had quantifiable HBV RNA while only 37% had quantifiable HBV DNA. CONCLUSION: HBV RNA has signature profiles in different stages of chronic HBV infected patients receiving first-line NAs. During antiviral treatment, HBV RNA can still monitor the virus activity in patients whose serum HBV DNA cannot be detected.

Characteristics of HBV Novel Serum Markers across Distinct Phases in Treatment-Naïve Chronic HBV-Infected Patients.

Methods: A total of 111 patients in total from different disease phases were recruited, including 21 in immune-tolerant (IT) phase, 49 in immune-clearance (IC) phases, 29 in immune-control or low replicative (LR) phase, and 12 in reactivation phases. Serum HBV RNA, anti-HBc, HBcrAg, and intrahepatic covalently closed circular DNA (cccDNA) were quantified and each of these indicator's correlation with liver inflammation was analyzed. Results: HBeAg-positive individuals had significant higher serum levels of HBV RNA and HBcrAg than those who were HBeAg negative, similar to that of serum HBV DNA. Comparatively, HBV RNA (r =0.79, P < 0.01) and HBcrAg (r =0.78, P < 0.01) had almost same higher overall correlation with the cccDNA, as that of HBV DNA (r =0.81, P < 0.01). Serum anti-HBc level (r = -0.52, P < 0.05) is negatively correlated with cccDNA level at IT phase rather than the other three phases. When set the cutoff value at 4.00 log10 IU/mL, serum anti-HBc showed potential to indicate liver inflammation, with AUC as 0.79 and the specificities as 78.85% for HBeAg positive, and with AUC as 0.72 and the specificities as 62.16% for HBeAg-negative patients, respectively. Conclusions: In treatment-naïve patients, levels of serological markers HBV RNA and HBcrAg could mirror intrahepatic cccDNA level, but were not superior to HBV DNA level. Serum anti-HBc level had certain potential to be used as a predicting marker for liver inflammation.

Serum HBV DNA plus RNA reflecting cccDNA level before and during NAs treatment in HBeAg positive CHB patients.

Background & Aims: Correlations between serum viral markers and intrahepatic cccDNA in patients undergoing long-term nucleos(t)ide analogues (NAs) treatment haven't been fully explored. In this study, we evaluate the correlation between intrahepatic cccDNA and other serum viral markers and intrahepatic HBV DNA in HBeAg positive chronic hepatitis B (CHB) patients during 60-month treatment with NAs. Methods: Fifty-four HBeAg positive CHB patients received long-term NAs treatment were included in this study. Serial serum samples were regularly collected and quantitatively analyzed for HBsAg, HBV DNA, HBV RNA and HBcrAg. Histological samples from liver biopsy at baseline and month 60 were analyzed for intrahepatic HBV DNA and cccDNA. Results: At baseline, serum HBV DNA plus RNA was positively associated with intrahepatic cccDNA in multivariate regression analysis (ß=0.205, P<0.001). In the correlation analysis between cccDNA and serum viral markers, HBV DNA plus RNA had the highest correlation coefficient (r=0.698, P<0.001), followed by serum HBV DNA (r=0.641, P<0.001), HBV RNA (r=0.590, P<0.001), and HBcrAg (r=0.564, P<0.001). At month 60, correlations between these serum viral markers and cccDNA were not observed (P>0.05). Multivariate regression analysis showed that only the decreased HBV DNA plus RNA was positively associated with cccDNA decline (ß=0.172, P =0.006). Changes of HBV DNA plus RNA (r=0.525, P=0.001) was better correlated with cccDNA decline as compared to HBV RNA (r=0.384, P=0.008), HBV DNA (r=0.431, P=0.003), and HBsAg (r=0.342, P=0.029). Conclusions: Serum HBV DNA plus RNA better correlated with intrahepatic cccDNA than other viral makers before and during NAs treatment in HBeAg positive CHB patients.

Solely HBsAg intrauterine exposure accelerates HBV clearance by promoting HBs-specific immune response in the mouse pups.

Chronic hepatitis B virus (HBV) infection due to perinatal mother-to-infant transmission (MTIT) remains a serious global public health problem. It has been shown that intrauterine exposure to HBV antigens might account for the MTIT-related chronic infection. However, whether hepatitis B surface antigen (HBsAg) intrauterine exposure affected the offspring's immune response against HBV and MTIT of HBV has not been fully clarified. In this study, we investigated the effects and the potential mechanisms of the HBsAg intrauterine exposure on the persistence of HBV replication using a solely HBsAg intrauterine exposure mice model. Our results revealed that solely HBsAg intrauterine exposure significantly accelerated the clearance of HBV when these mice were hydrodynamically injected with pBB4.5-HBV1.2 plasmids after birth, which may be due to the increased number of HBs-specific CD8+ T cells and interferon-gamma secretion in the liver of mice. Mechanismly, HBsAg intrauterine exposure activated antigen-presenting dendritic cells, which led to the generation of antigen-specific cellular immunological memory. Our data provide an important experimental evidence for the activation of neonatal immune response by HBsAg intrauterine exposure.

Serum HBV RNA predicts HBeAg clearance and seroconversion in patients with chronic hepatitis B treated with nucleos(t)ide analogues.

This study evaluated the predictive value of serum HBV DNA, HBV RNA, HBcrAg, HBsAg, intrahepatic HBV DNA and cccDNA for HBeAg clearance and seroconversion during long-term treatment with nucleos(t)ide analogues (NAs) in patients with chronic hepatitis B (CHB). A single centre, prospective cohort of CHB patients was used for this study. Serum HBV RNA levels were retrospectively measured at baseline, 6, 12, 24, 36, 48, 60, 72 and 84 months post-NAs treatment. Serum HBsAg and HBcrAg levels were quantified at baseline, month 6, 60 and 72. Histological samples from liver biopsy at baseline and month 60 were analysed for intrahepatic HBV DNA and cccDNA. Eighty-three HBeAg-positive patients were enrolled with a median follow-up time of 108 months (range 18-138 months). Of them, 53 (63.86%) patients achieved HBeAg clearance, and 37 (44.58%) achieved HBeAg seroconversion. Cox multivariate analysis showed that only baseline HBV RNA was independently associated with HBeAg clearance and seroconversion (<5.45 log10 copies/mL, HR = 5.06, 95% CI: 1.87-13.71, p = .001; HR = 3.38, 95% CI: 1.28-8.91, p = .01). The independent association with HBeAg clearance and seroconversion remained for HBV RNA levels at month 6 (<4.72 log10 copies/mL, HR = 4.16, 95% CI: 1.61-10.72, p = .003; HR = 6.52, 95% CI: 1.85-22.94, p = .003) and month 12 (<4.08 log10 copies/mL, HR = 3.68, 95% CI: 1.96-6.90, p < .001; HR = 2.79, 95% CI: 1.31-5.94, p = .008). The AUCs of baseline HBV RNA for predicting the HBeAg clearance (0.83, 95% CI: 0.70-0.96, 0.83, 95% CI: 0.70-0.96 and 0.82, 95% CI: 0.69-0.95 respectively) and seroconversion (0.89, 95% CI: 0.77-1.00; 0.81, 95% CI: 0.66-0.95 and 0.84, 95% CI: 0.71-0.98 respectively) at month 36, 60 and 84 were higher than those of HBV DNA, HBsAg and HBcrAg. In conclusion, lower serum HBV RNA at baseline, month 6 and 12 post-NAs treatment could predict HBeAg clearance and seroconversion during long-term NAs treatment.

A standardized assay for the quantitative detection of serum HBV RNA in chronic hepatitis B patients.

Serum hepatitis B virus (HBV) pregenomic RNA (pgRNA) is a surrogate marker for reflecting the transcriptional activity of covalently closed circular DNA. However, there is still no standardized assay for the quantitative detection of serum HBV RNA in chronic hepatitis B patients. In this study, quantitative polymerase chain reactions for detecting the preC/C-RNA (preC/C region HBV pgRNA), SF-RNA (splicing variants-free pgRNA) and XR-RNA (X region remained pgRNA) regions were set up. The dynamic changes of serum pgRNA splicing variants and 3' terminal truncations were analysed in three retrospective cohorts: 35 treatment-naive chronic HBV-infected patients (cohort A), 52 chronic hepatitis B (CHB) patients who received nucleos(t)ide analogs (NAs) therapy for 48 weeks (cohort B) and eight CHB patients who are under long-term NAs treatment (cohort C). The accuracy and sensitivity of HBV RNA detection were assessed by the National Standard of HBV RNA. We confirmed that high proportions of pgRNA splicing variants and 3' terminal truncations were present and significantly affect the quantitative detection of serum HBV RNA in both treatment-naive and NAs-treated CHB patients. To achieve the higher accuracy and sensitivity on the detection of HBV RNA level, the primers and probes should be designed at the 5' terminal region of HBV genome and outside the mainly spliced sequence of pgRNA, especially for CHB patients under long-term NAs treatment. This study would help to better understand the significance of the pgRNA splicing variants and 3' terminal truncations, and further guide the clinical detection of serum HBV RNA.

Hepatitis B Virus Virions Produced Under Nucleos(t)ide Analogue Treatment Are Mainly Not Infectious Because of Irreversible DNA Chain Termination.

Nucleos(t)ide analogues (NAs) have been widely used for the treatment of chronic hepatitis B (CHB). Because viral DNA polymerase lacks proofreading function (3' exonuclease activity), theoretically, the incorporated NAs would irreversibly terminate viral DNA synthesis. This study explored the natures of nascent hepatitis B virus (HBV) DNA and infectivity of progeny virions produced under NA treatment. HBV infectivity was determined by infection of HepG2-NTCP cells and primary human hepatocytes (PHHs). Biochemical properties of HBV DNA in the progeny virions were investigated by qPCR, northern blotting, or Southern blotting hybridization, sucrose gradient centrifugation, and in vitro endogenous DNA polymerase assay. Progeny HBV virions produced under NA treatment were mainly not infectious to HepG2-NTCP cells or PHHs. Biochemical analysis revealed that under NA treatment, HBV DNA in nucleaocapsids or virions were predominantly short minus-strand DNA with irreversible termination. This finding was supported by the observation of first disappearance of relaxed circular DNA and then the proportional decline of HBV-DNA levels corresponding to the regions of PreC/C, S, and X genes in serial sera of patients receiving NA treatment. Conclusion: HBV virions produced under NA treatment are predominantly replication deficient because the viral genomes are truncated and elongation of DNA chains is irreversibly terminated. Clinically, our results suggest that the viral loads of CHB patients under NA therapy vary with the different regions of genome being detected by qPCR assays. Our findings also imply that NA prevention of perinatal and sexual HBV transmission as well as infection of transplanted livers works not only by reducing viral loads, but also by producing noninfectious virions.

HBV Genome and Life Cycle.

Chronic hepatitis B virus (HBV) infection remains to be a serious threat to public health and is associated with many liver diseases including chronic hepatitis B (CHB), liver cirrhosis, and hepatocellular carcinoma. Although nucleos(t)ide analogues (NA) and pegylated interferon-α (Peg-IFNα) have been confirmed to be efficient in inhibiting HBV replication, it is difficult to eradicate HBV and achieve the clinical cure of CHB. Therefore, long-term therapy has been recommended to CHB treatment under the current antiviral therapy. In this context, the new antiviral therapy targeting one or multiple critical steps of viral life cycle may be an alternative approach in future. In the last decade, the functional receptor [sodium-taurocholate cotransporting polypeptide (NTCP)] of HBV entry into hepatocytes has been discovered, and the immature nucleocapsids containing the non- or partially reverse-transcribed pregenomic RNA, the nucleocapsids containing double-strand linear DNA (dslDNA), and the empty particles devoid of any HBV nucleic acid have been found to be released into circulation, which have supplemented the life cycle of HBV. The understanding of HBV life cycle may offer a new instruction for searching the potential antiviral targets, and the new viral markers used to monitor the efficacy of antiviral therapy for CHB patients in the future.

Friend or Foe? Evidence Indicates Endogenous Exosomes Can Deliver Functional gRNA and Cas9 Protein.

The clustered regularly interspaced short palindromic repeats (CRISPR)/associated nuclease (Cas) system is an efficient gene editing tool. In this study, it is found that both single guide RNA (gRNA) and Cas9 protein could be exported from the CRISPR/Cas9-expressing cells by endogenous exosomes independently. Further experiments demonstrate that these naturally produced endogenous exosomes could be used as a vehicle to deliver the functional Cas9 and hepatitis B virus (HBV)-specific gRNA to cut HBV DNA transfected in HuH7 cells or human papilloma virus (HPV)-specific gRNA to cut the integrated HPV DNA in HeLa cells, respectively. In conclusion, this study indicates the potential of endogenous exosomes as a safe and effective delivery vehicle of the functional gRNA and Cas9 protein. Meanwhile, the endogenous exosomes-mediated delivery of gene editing activity to adjacent and distant cells or tissues may further complicate the off-target and safety concerns about the CRISPR/Cas9 system.

Determination of biological removal of recalcitrant organic contaminants in coal gasification waste water.

Coal gasification waste water treatment needed a sustainable and affordable plan to eliminate the organic contaminants in order to lower the potential environmental and human health risk. In this paper, a laboratory-scale anaerobic-aerobic intermittent system carried out 66 operational cycles together for the treatment of coal gasification waste water and the removal capacity of each organic pollutant. Contaminants included phenols, carboxylic acids, long-chain hydrocarbons, and heterocyclic compounds, wherein the relative content of phenol is up to 57.86%. The long-term removal of 77 organic contaminants was evaluated at different hydraulic retention time (anaerobic24 h + aerobic48 h and anaerobic48 h +aerobic48 h). Contaminant removal ranged from no measurable removal to near-complete removal with effluent concentrations below the detection limit. Contaminant removals followed one of four trends: steady-state removal throughout, increasing removal to steady state (acclimation), decreasing removal, and no removal. Organic degradation and transformation in the reaction were analysed by gas chromatography/mass spectrometry technology.