Circulating metabolites are associated with persistent elevations of ALT in patients with chronic hepatitis B with complete viral suppression.

Hepatitis B virus (HBV) can be completely suppressed after antiviral treatment; however, some patients with chronic hepatitis B (CHB) exhibit elevated alanine aminotransferase (ALT) levels and sustained disease progression. This study provides novel insights into the mechanism and potential predictive biomarkers of persistently elevated ALT (PeALT) in patients with CHB after complete viral inhibition. Patients having CHB with undetectable HBV DNA at least 12 months after antiviral treatment were enrolled from a prospective, observational cohort. Patients with PeALT and persistently normal ALT (PnALT) were matched 1:1 using propensity score matching. Correlations between plasma metabolites and the risk of elevated ALT were examined using multivariate logistic regression. A mouse model of carbon tetrachloride-induced liver injury was established to validate the effect of key differential metabolites on liver injury. Of the 1238 patients with CHB who achieved complete viral suppression, 40 (3.23%) had PeALT levels during follow-up (median follow-up: 2.42 years). Additionally, 40 patients with PnALT levels were matched as controls. Ser-Phe-Ala, Lys-Ala-Leu-Glu, 3-methylhippuric acid, 3-methylxanthine, and 7-methylxanthine were identified as critical differential metabolites between the two groups and independently associated with PeALT risk. Ser-Phe-Ala and Lys-Ala-Leu-Glu levels could be used to discriminate patients with PeALT from those with PnALT. Furthermore, N-acetyl- l-methionine (NALM) demonstrated the strongest negative correlation with ALT levels. NALM supplementation alleviated liver injury and hepatic necrosis induced by carbon tetrachloride in mice. Changes in circulating metabolites may contribute to PeALT levels in patients with CHB who have achieved complete viral suppression after antiviral treatment.

Exosomes target HBV-host interactions to remodel the hepatic immune microenvironment.

Chronic hepatitis B poses a significant global burden, modulating immune cells, leading to chronic inflammation and long-term damage. Due to its hepatotropism, the hepatitis B virus (HBV) cannot infect other cells. The mechanisms underlying the intercellular communication among different liver cells in HBV-infected individuals and the immune microenvironment imbalance remain elusive. Exosomes, as important intercellular communication and cargo transportation tools between HBV-infected hepatocytes and immune cells, have been shown to assist in HBV cargo transportation and regulate the immune microenvironment. However, the role of exosomes in hepatitis B has only gradually received attention in recent years. Minimal literature has systematically elaborated on the role of exosomes in reshaping the immune microenvironment of the liver. This review unfolds sequentially based on the biological processes of exosomes: exosomes' biogenesis, release, transport, uptake by recipient cells, and their impact on recipient cells. We delineate how HBV influences the biogenesis of exosomes, utilizing exosomal covert transmission, and reshapes the hepatic immune microenvironment. And based on the characteristics and functions of exosomes, potential applications of exosomes in hepatitis B are summarized and predicted.

Lower HBV DNA level is associated with more severe liver fibrosis in HBeAg-positive chronic hepatitis B with normal alanine transaminase.

BACKGROUND: The association of hepatitis B virus (HBV) DNA levels and liver fibrosis in chronic hepatitis B (CHB) patients with immune-tolerant phase remains unclear. We explored the association between liver fibrosis and HBV DNA levels in HBeAg-positive CHB patients with normal alanine transaminase (ALT) with relatively high HBV DNA. METHODS: Six hundred and twenty-two HBeAg-positive CHB patients with normal ALT were included. Patients were divided into three categories: low (6 log10 IU/mL ≤ HBV DNA < 7 log10 IU/mL), moderate (7 log10 IU/mL ≤ HBV DNA < 8 log10 IU/mL), and high (HBV DNA ≥ 8 log10 IU/mL). APRI, FIB-4, transient elastography, or liver biopsy were used to assess liver fibrosis. RESULTS: The median age of patients was 33.0 years and 57.9% patients were male. 18.8%, 52.1%, and 29.1% of patients had low, moderate, and high HBV DNA levels, respectively. The APRI (0.33 vs. 0.26 vs. 0.26, P < 0.001), FIB-4 (1.03 vs. 0.71 vs. 0.68, P < 0.001), and LSM values (7.6 kPa vs. 5.6 kPa vs. 5.5 kPa, P = 0.086) were higher in low HBV DNA group than other two groups. Low HBV DNA group had higher proportions of significant fibrosis (24.8% vs. 9.9% vs. 3.3%, P < 0.001) and cirrhosis (7.7% vs. 2.5% vs. 1.1%, P = 0.004) than moderate and high HBV DNA groups. Moderate (OR 3.095, P = 0.023) and low (OR 4.968, P = 0.003) HBV DNA were independent risk factors of significant fibrosis. CONCLUSION: Lower HBV DNA level was associated with more severe liver fibrosis in HBeAg-positive CHB patients with ALT.

Long-term antiviral therapy is associated with changes in the profile of transcriptionally active HBV integration in the livers of patients with CHB.

Hepatitis B virus (HBV) integration exists throughout the clinical course of chronic hepatitis B (CHB). This study investigated the effects of long-term antiviral therapy on the level and profiles of transcriptionally active HBV integration. Serial liver biopsies and paired blood samples were obtained from 16, 16, and 22 patients with CHB at baseline, 78, and 260 weeks of entecavir monotherapy or combined with pegylated interferon alfa, respectively. Serum HBV biomarkers were longitudinally assessed. RNA-seq and HIVID2 program was used to identify HBV-host chimeric RNAs transcribed from integrated DNA. The counts of HBV integration reads were positively related to both serum HBV DNA levels (r = 0.695, p = 0.004) and HBeAg titers (r = 0.724, p = 0.021) at baseline, but the positive correlation exited only to the serum HBsAg levels after 260 weeks of antiviral therapy (r = 0.662, p = 0.001). After 78 weeks of antiviral therapy, the levels of HBV integration expression decreased by 12.25 folds from baseline. The viral junction points were enriched at the S and HBx genes after the long-term antiviral therapy. HBs-FN1 became one of the main transcripts, with the mean proportion of HBs-FN1 in all integrated expression increased from 2.79% at baseline to 10.54% at Week 260 of antiviral treatment. Antiviral therapy may reduce but not eliminate the HBV integration events and integration expression. Certain integration events, such as HBs-FN1 can persist in long-term antiviral treatment.

Evaluation of two inoculation routes of an adenovirus-mediated viral protein inhibitor in a Crimean-Congo hemorrhagic fever mouse model.

Crimean-Congo hemorrhagic fever virus (CCHFV) is a tick-borne nairovirus with a wide geographic spread that can cause severe and lethal disease. No specific medical countermeasures are approved to combat this illness. The CCHFV L protein contains an ovarian tumor (OTU) domain with a cysteine protease thought to modulate cellular immune responses by removing ubiquitin and ISG15 post-translational modifications from host and viral proteins. Viral deubiquitinases like CCHFV OTU are attractive drug targets, as blocking their activity may enhance cellular immune responses to infection, and potentially inhibit viral replication itself. We previously demonstrated that the engineered ubiquitin variant CC4 is a potent inhibitor of CCHFV replication in vitro. A major challenge of the therapeutic use of small protein inhibitors such as CC4 is their requirement for intracellular delivery, e.g., by viral vectors. In this study, we examined the feasibility of in vivo CC4 delivery by a replication-deficient recombinant adenovirus (Ad-CC4) in a lethal CCHFV mouse model. Since the liver is a primary target of CCHFV infection, we aimed to optimize delivery to this organ by comparing intravenous (tail vein) and intraperitoneal injection of Ad-CC4. While tail vein injection is a traditional route for adenovirus delivery, in our hands intraperitoneal injection resulted in higher and more widespread levels of adenovirus genome in tissues, including, as intended, the liver. However, despite promising in vitro results, neither route of in vivo CC4 treatment resulted in protection from a lethal CCHFV infection.

Galectin-3-ITGB1 Signaling Mediates Interleukin 10 Production of Hepatic Conventional Natural Killer Cells in Hepatitis B Virus Transgenic Mice and Correlates with Hepatocellular Carcinoma Progression in Patients.

BACKGROUND AND AIMS: The outcomes of HBV infections are related to complex immune imbalances; however, the precise mechanisms by which HBV induces immune dysfunction are not well understood. METHODS: HBV transgenic (HBs-Tg) mice were used to investigate intrahepatic NK cells in two distinct subsets: conventional NK (cNK) and liver-resident NK (LrNK) cells during a chronic HBV infection. RESULTS: The cNK cells, but not the LrNK cells, were primarily responsible for the increase in the number of bulk NK cells in the livers of ageing HBs-Tg mice. The hepatic cNK cells showed a stronger ability to produce IL-10, coupled with a higher expression of CD69, TIGIT and PD-L1, and lower NKG2D expression in ageing HBs-Tg mice. A lower mitochondrial mass and membrane potential, and less polarized localization were observed in the hepatic cNK cells compared with the splenic cNK cells in the HBs-Tg mice. The enhanced galectin-3 (Gal-3) secreted from HBsAg+ hepatocytes accounted for the IL-10 production of hepatic cNK cells via ITGB1 signaling. For humans, LGALS3 and ITGB1 expression is positively correlated with IL-10 expression, and negatively correlated with the poor clinical progression of HCC. CONCLUSIONS: Gal-3-ITGB1 signaling shapes hepatic cNK cells but not LrNK cells during a chronic HBV infection, which may correlate with HCC progression.

Current perspectives of viral hepatitis.

Viral hepatitis represents a major danger to public health, and is a globally leading cause of death. The five liver-specific viruses: Hepatitis A virus, hepatitis B virus, hepatitis C virus, hepatitis D virus, and hepatitis E virus, each have their own unique epidemiology, structural biology, transmission, endemic patterns, risk of liver complications, and response to antiviral therapies. There remain few options for treatment, in spite of the increasing prevalence of viral-hepatitis-caused liver disease. Furthermore, chronic viral hepatitis is a leading worldwide cause of both liver-related morbidity and mortality, even though effective treatments are available that could reduce or prevent most patients' complications. In 2016, the World Health Organization released its plan to eliminate viral hepatitis as a public health threat by the year 2030, along with a discussion of current gaps and prospects for both regional and global eradication of viral hepatitis. Today, treatment is sufficiently able to prevent the disease from reaching advanced phases. However, future therapies must be extremely safe, and should ideally limit the period of treatment necessary. A better understanding of pathogenesis will prove beneficial in the development of potential treatment strategies targeting infections by viral hepatitis. This review aims to summarize the current state of knowledge on each type of viral hepatitis, together with major innovations.

An IFNγ-dependent immune-endocrine circuit lowers blood glucose to potentiate the innate antiviral immune response.

Viral infection makes us feel sick as the immune system alters systemic metabolism to better fight the pathogen. The extent of these changes is relative to the severity of disease. Whether blood glucose is subject to infection-induced modulation is mostly unknown. Here we show that strong, nonlethal infection restricts systemic glucose availability, which promotes the antiviral type I interferon (IFN-I) response. Following viral infection, we find that IFNγ produced by γδ T cells stimulates pancreatic ß cells to increase glucose-induced insulin release. Subsequently, hyperinsulinemia lessens hepatic glucose output. Glucose restriction enhances IFN-I production by curtailing lactate-mediated inhibition of IRF3 and NF-κB signaling. Induced hyperglycemia constrained IFN-I production and increased mortality upon infection. Our findings identify glucose restriction as a physiological mechanism to bring the body into a heightened state of responsiveness to viral pathogens. This immune-endocrine circuit is disrupted in hyperglycemia, possibly explaining why patients with diabetes are more susceptible to viral infection.

Liver injury and prolonged hospitalization as indicators of severity in patients with adenovirus infections.

BACKGROUND: Adenovirus (ADV) is a prevalent infective virus in children, accounting for around 5-10% of all cases of acute respiratory illnesses and 4-15% of pneumonia cases in children younger than five years old. Without treatment, severe ADV pneumonia could result in fatality rates of over 50% in cases of emerging strains or disseminated disease. This study aims to uncover the relationship of clinical indicators with primary ADV infection severity, regarding duration of hospitalization and liver injury. METHODS: In this retrospective study, we collected and analyzed the medical records of 1151 in-patients who met the inclusion and exclusion criteria. According to duration of hospitalization, all patients were divided into three groups. Then the difference and correlation of clinical indicators with ADV infection were analyzed, and the relationship among liver injury, immune cells and cytokines was evaluated. RESULTS: The study revealed that patients with a duration of hospitalization exceeding 14 days had the highest percentage of abnormalities across most indicators. This was in contrast to the patients with a hospitalization duration of either less than or equal to 7 days or between 7 and 14 days. Furthermore, correlation analysis indicated that a longer duration of body temperature of ≥ 39°C, bilateral lung lobes infiltration detected by X ray, abnormal levels of AST, PaO2, and SPO2, and a lower age were all predictive of longer hospital stays. Furthermore, an elevated AST level and reduced liver synthesis capacity were related with a longer hospital stay and higher ADV copy number. Additionally, AST/ALT was correlated positively with IFN-γ level and IFN-γ level was only correlated positively with CD4+ T cells. CONCLUSIONS: The study provided a set of predicting indicators for longer duration of hospitalization, which responded for primary severe ADV infection, and elucidated the possible reason for prolonged duration of hospitalization attributing to liver injury via higher ADV copy number, IFN-γ and CD4+ T cells, which suggested the importance of IFN-γ level and liver function monitoring for the patients with primary severe ADV infection.

Inhibition of hepatitis B virus via selective apoptosis modulation by Chinese patent medicine Liuweiwuling Tablet.

BACKGROUND: Liuweiwuling Tablet (LWWL) is a Chinese patent medicine approved for the treatment of chronic inflammation caused by hepatitis B virus (HBV) infection. Previous studies have indicated an anti-HBV effect of LWWL, specifically in terms of antigen inhibition, but the underlying mechanism remains unclear. AIM: To investigate the potential mechanism of action of LWWL against HBV. METHODS: In vitro experiments utilized three HBV-replicating and three non-HBV-replicating cell lines. The in vivo experiment involved a hydrodynamic injection-mediated mouse model with HBV replication. Transcriptomics and metabolomics were used to investigate the underlying mechanisms of action of LWWL. RESULTS: In HepG2.1403F cells, LWWL (0.8 mg/mL) exhibited inhibitory effects on HBV DNA, hepatitis B surface antigen and pregenomic RNA (pgRNA) at rates of 51.36%, 24.74% and 50.74%, respectively. The inhibition rates of LWWL (0.8 mg/mL) on pgRNA/covalently closed circular DNA in HepG2.1403F, HepG2.2.15 and HepG2.A64 cells were 47.78%, 39.51% and 46.74%, respectively. Integration of transcriptomics and metabolomics showed that the anti-HBV effect of LWWL was primarily linked to pathways related to apoptosis (PI3K-AKT, CASP8-CASP3 and P53 pathways). Apoptosis flow analysis revealed that the apoptosis rate in the LWWL-treated group was significantly higher than in the control group (CG) among HBV-replicating cell lines, including HepG2.2.15 (2.92% ± 1.01% vs 6.68% ± 2.04%, P < 0.05), HepG2.A64 (4.89% ± 1.28% vs 8.52% ± 0.50%, P < 0.05) and HepG2.1403F (3.76% ± 1.40% vs 7.57% ± 1.35%, P < 0.05) (CG vs LWWL-treated group). However, there were no significant differences in apoptosis rates between the non-HBV-replicating HepG2 cells (5.04% ± 0.74% vs 5.51% ± 1.57%, P > 0.05), L02 cells (5.49% ± 0.80% vs 5.48% ± 1.01%, P > 0.05) and LX2 cells (6.29% ± 1.54% vs 6.29% ± 0.88%, P > 0.05). TUNEL staining revealed a significantly higher apoptosis rate in the LWWL-treated group than in the CG in the HBV-replicating mouse model, while no noticeable difference in apoptosis rates between the two groups was observed in the non-HBV-replicating mouse model. CONCLUSION: Preliminary results suggest that LWWL exerts a potent inhibitory effect on wild-type and drug-resistant HBV, potentially involving selective regulation of apoptosis. These findings offer novel insights into the anti-HBV activities of LWWL and present a novel mechanism for the development of anti-HBV medications.

Liver biopsy in the post-hepatitis C virus era in Japan.

In Japan, liver biopsies were previously crucial in evaluating the severity of hepatitis caused by the hepatitis C virus (HCV) and diagnosing HCV-related hepatocellular carcinoma (HCC). However, due to the development of effective antiviral treatments and advanced imaging, the necessity for biopsies has significantly decreased. This change has resulted in fewer chances for diagnosing liver disease, causing many general pathologists to feel less confident in making liver biopsy diagnoses. This article provides a comprehensive overview of the challenges and potential solutions related to liver biopsies in Japan. First, it highlights the importance of considering steatotic liver diseases as independent conditions that can coexist with other liver diseases due to their increasing prevalence. Second, it emphasizes the need to avoid hasty assumptions of HCC in nodular lesions, because clinically diagnosable HCCs are not targets for biopsy. Third, the importance of diagnosing hepatic immune-related adverse events caused by immune checkpoint inhibitors is increasing due to the anticipated widespread use of these drugs. In conclusion, pathologists should be attuned to the changing landscape of liver diseases and approach liver biopsies with care and attention to detail.

Integrated multi-omics analysis reveals liver metabolic reprogramming by fish iridovirus and antiviral function of alpha-linolenic acid.

Iridovirus poses a substantial threat to global aquaculture due to its high mortality rate; however, the molecular mechanisms underpinning its pathogenesis are not well elucidated. Here, a multi-omics approach was applied to groupers infected with Singapore grouper iridovirus (SGIV), focusing on the roles of key metabolites. Results showed that SGIV induced obvious histopathological damage and changes in metabolic enzymes within the liver. Furthermore, SGIV significantly reduced the contents of lipid droplets, triglycerides, cholesterol, and lipoproteins. Metabolomic analysis indicated that the altered metabolites were enriched in 19 pathways, with a notable down-regulation of lipid metabolites such as glycerophosphates and alpha-linolenic acid (ALA), consistent with disturbed lipid homeostasis in the liver. Integration of transcriptomic and metabolomic data revealed that the top enriched pathways were related to cell growth and death and nucleotide, carbohydrate, amino acid, and lipid metabolism, supporting the conclusion that SGIV infection induced liver metabolic reprogramming. Further integrative transcriptomic and proteomic analysis indicated that SGIV infection activated crucial molecular events in a phagosome-immune depression-metabolism dysregulation-necrosis signaling cascade. Of note, integrative multi-omics analysis demonstrated the consumption of ALA and linoleic acid (LA) metabolites, and the accumulation of L-glutamic acid (GA), accompanied by alterations in immune, inflammation, and cell death-related genes. Further experimental data showed that ALA, but not GA, suppressed SGIV replication by activating antioxidant and anti-inflammatory responses in the host. Collectively, these findings provide a comprehensive resource for understanding host response dynamics during fish iridovirus infection and highlight the antiviral potential of ALA in the prevention and treatment of iridoviral diseases.

The lack of HBsAg secretion does neither facilitate induction of antiviral T cell responses nor Hepatitis B Virus clearance in mice.

Immune tolerance to the hepatitis B virus (HBV) is crucial for developing chronic hepatitis B, and the HBV surface antigen (HBsAg) produced and secreted in high amounts is regarded as a key contributor. HBsAg is expressed in HBV-infected hepatocytes and those carrying an HBV integration. Whether either HBsAg secretion or the high antigen amount expressed in the liver determines its immunomodulatory properties, however, remains unclear. We, therefore, developed a novel HBV animal model that allowed us to study the role of secreted HBsAg. We introduced a previously described HBs mutation, C65S, abolishing HBsAg secretion into a replication-competent 1.3-overlength HBV genome and used adeno-associated virus vectors to deliver it to the mouse liver. The AAV-HBV established a carrier state of wildtype and C65S mutant HBV, respectively. We investigated antiviral B- and T-cell immunity in the HBV-carrier mice after therapeutic vaccination. Moreover, we compared the effect of a lacking HBsAg secretion with that of an antiviral siRNA. While missing HBsAg secretion allowed for higher levels of detectable anti-HBs antibodies after therapeutic vaccination, it did neither affect antiviral T-cell responses nor intrahepatic HBV gene expression, irrespective of the starting level. A treatment with HBV siRNA restricting viral antigen expression within hepatocytes, however, improved the antiviral efficacy of therapeutic vaccination, irrespective of the ability of HBV to secrete HBsAg. Our data indicate that clearing HBsAg from blood cannot significantly impact HBV persistence or T-cell immunity. This indicates that a restriction of hepatic viral antigen expression will be required to break HBV immunotolerance.

A mutual regulatory loop between transcription factor Yin Yang 1 and hepatitis B virus replication influences chronic hepatitis B.

Hepatitis B virus (HBV) infections pose a major threat to human health. HBV can upregulate the expression of the transcription factor Yin Yang 1 (YY1) in in vitro cytological experiments, suggesting an association between YY1 and HBV infection. However, data on YY1 expression in chronic hepatitis B (CHB) patients are lacking. In this study, we aimed to assess the correlation between YY1 expression and HBV infection. We detected serum YY1 levels in 420 patients with chronic HBV infection, 30 patients with chronic hepatitis C virus infection, and 32 healthy controls using an enzyme-linked immunosorbent assay. The correlation between YY1 levels and clinical parameters was analyzed. Meanwhile, the changes of YY1 before and after interferon or entecavir treatment were analyzed. YY1 levels in the liver tissues were detected using immunofluorescence staining. The expression of YY1 in HBV-expressing cells was detected through western blotting. Meanwhile, we explored the effects of YY1 on HBV replication and gene expression. We found that YY1 was highly expressed in the serum and liver tissues of CHB patients. Serum YY1 levels positively correlated with HBV DNA and hepatitis B surface antigen (HBsAg). Additionally, HBV DNA levels increased but HBsAg levels decreased after HBV-expressing cells overexpress YY1. In conclusion, our study demonstrates that YY1 plays an important role in HBV replication and gene expression, providing a potential target for the treatment of CHB.

An outbreak of hepatitis E virus genotype 4d caused by consuming undercooked pig liver in a nursing home in Zhejiang Province, China.

Hepatitis E infection is typically caused by contaminated water or food. In July and August 2022, an outbreak of hepatitis E was reported in a nursing home in Zhejiang Province, China. Local authorities and workers took immediate actions to confirm the outbreak, investigated the sources of infection and routes of transmission, took measures to terminate the outbreak, and summarized the lessons learned. An epidemiological investigation was conducted on all individuals in the nursing home, including demographic information, clinical symptoms, history of dietary, water intake and contact. Stool and blood samples were collected from these populations for laboratory examinations. The hygiene environment of the nursing home was also investigated. A case-control study was conducted to identify the risk factors for this outbreak. Of the 722 subjects in the nursing home, 77 were diagnosed with hepatitis E, for an attack rate of 10.66 %. Among them, 18 (23.38 %, 18/77) individuals had symptoms such as jaundice, fever, and loss of appetite and were defined as the population with hepatitis E. The average age of people infected with hepatitis E virus (HEV) was 59.96 years and the attack rate of hepatitis E among women (12.02 %, 59/491) was greater than that among men (7.79 %, 18/231). The rate was the highest among caregivers (22.22 %, 32/144) and lowest among logistics personnel (6.25 %, 2/32); however, these differences were not statistically significant (P > 0.05). Laboratory sequencing results indicated that the genotype of this hepatitis E outbreak was 4d. A case-control study showed that consuming pig liver (odds ratio (OR) = 7.50; 95 % confidence interval [CI]: 3.84-16.14, P < 0.001) and consuming raw fruits and vegetables (OR = 5.92; 95 % CI: 1.74-37.13, P = 0.017) were risk factors for this outbreak of Hepatitis E. Moreover, a monitoring video showed that the canteen personnel did not separate raw and cooked foods, and pig livers were cooked for only 2 min and 10 s. Approximately 1 month after the outbreak, an emergency vaccination for HEV was administered. No new cases were reported after two long incubation periods (approximately 4 months). The outbreak of HEV genotype 4d was likely caused by consuming undercooked pig liver, resulting in an attack rate of 10.66 %. This was related to the rapid stir-frying cooking method and the hygiene habit of not separating raw and cooked foods.

The Biodistribution of Replication-Defective Simian Adenovirus 1 Vector in a Mouse Model.

The administration route affects the biodistribution of a gene transfer vector and the expression of a transgene. A simian adenovirus 1 vector carrying firefly luciferase and GFP reporter genes (SAdV1-GFluc) were constructed, and its biodistribution was investigated in a mouse model by bioluminescence imaging and virus DNA tracking with real-time PCR. Luciferase activity and virus DNA were mainly found in the liver and spleen after the intravenous administration of SAdV1-GFluc. The results of flow cytometry illustrated that macrophages in the liver and spleen as well as hepatocytes were the target cells. Repeated inoculation was noneffective because of the stimulated serum neutralizing antibodies (NAbs) against SAdV-1. A transient, local expression of low-level luciferase was detected after intragastric administration, and the administration could be repeated without compromising the expression of the reporter gene. Intranasal administration led to a moderate, constant expression of a transgene in the whole respiratory tract and could be repeated one more time without a significant increase in the NAb titer. An immunohistochemistry assay showed that respiratory epithelial cells and macrophages in the lungs were transduced. High luciferase activity was restricted at the injection site and sustained for a week after intramuscular administration. A compromised transgene expression was observed after a repeated injection. When these mice were intramuscularly injected for a third time with the human adenovirus 5 (HAdV-5) vector carrying a luciferase gene, the luciferase activity recovered and reached the initial level, suggesting that the sequential use of SAdV-1 and HAdV-5 vectors was practicable. In short, the intranasal inoculation or intramuscular injection may be the preferred administration routes for the novel SAdV-1 vector in vaccine development.

Single-cell RNA-sequencing of virus-specific cellular immune responses in chronic hepatitis B patients.

Chronic hepatitis B (CHB) is a major global health challenge. CHB can be controlled by antivirals but a therapeutic cure is lacking. CHB is characterized by limited HBV-specific T cell reactivity and functionality and expression of inhibitory receptors. The mechanisms driving these T cell phenotypes are only partially understood. Here, we created a single-cell RNA-sequencing dataset of HBV immune responses in patients to contribute to a better understanding of the dysregulated immunity. Blood samples of a well-defined cohort of 21 CHB and 10 healthy controls, including a subset of 5 matched liver biopsies, were collected. scRNA-seq data of total immune cells (55,825) plus sorted HBV-specific (1,963), non-naive (32,773) and PD1+ T cells (96,631) was generated using the 10X Genomics platform (186,123 cells) or the full-length Smart-seq2 protocol (1,069 cells). The shared transcript count matrices of single-cells serve as a valuable resource describing transcriptional changes underlying dysfunctional HBV-related T cell responses in blood and liver tissue and offers the opportunity to identify targets or biomarkers for HBV-related immune exhaustion.

Precore mutation enhances viral replication to facilitate persistent infection especially in HBeAg-negative patients.

Naturally occurred precore (PC, G1896A) and/or basal core promoter (BCP, A1762T/G1764A) mutations are prevalent in chronic HBV-infected patients, especially those under HBeAg-negative status. However, the replicative capacity of HBV with PC/BCP mutations remains ambiguous. Herein, meta-analysis showed that, only under HBeAg-negative status, the serum HBV DNA load in patients with PC mutation was 7.41-fold higher than those without the mutation. Both PC mutation alone and BCP â€‹+ â€‹PC mutations promoted HBV replication in cell and hydrodynamic injection mouse models. In human hepatocyte chimeric mouse model, BCP â€‹+ â€‹PC mutations led to elevated replicative capacity and intrahepatic core protein accumulation. Mechanistically, preC RNA harboring PC mutation could serve as mRNA to express core and P proteins, and such pgRNA-like function favored the maintenance of cccDNA pool under HBeAg-negative status. Additionally, BCP â€‹+ â€‹PC mutations induced more extensive and severe human hepatocyte damage as well as activated endoplasmic reticulum stress and TNF signaling pathway in livers of chimeric mice. This study indicates that HBeAg-negative patients should be monitored on HBV mutations regularly and are expected to receive early antiviral treatment to prevent disease progression.

Increased GABA signaling in liver macrophage promotes HBV replication in HBV-carrier mice.

Gamma-aminobutyric acid (GABA) signals in various non-neuronal cells including hepatocytes and some immune cells. Studies, including ours, show that type A GABA receptors (GABAARs)-mediated signaling occurs in macrophages regulating tissue-specific functions. Our recent study reveals that activation of GABAARs in liver macrophages promotes their M2-like polarization and increases HBV replication in mice. This short article briefly summarizes the GABA signaling system in macrophages and discusses potential mechanisms by which GABA signaling promotes HBV replication.

Oxygen-dependent histone lysine demethylase 4 restricts hepatitis B virus replication.

Mammalian cells have evolved strategies to regulate gene expression when oxygen is limited. Hypoxia-inducible factors (HIF) are the major transcriptional regulators of host gene expression. We previously reported that HIFs bind and activate hepatitis B virus (HBV) DNA transcription under low oxygen conditions; however, the global cellular response to low oxygen is mediated by a family of oxygenases that work in concert with HIFs. Recent studies have identified a role for chromatin modifiers in sensing cellular oxygen and orchestrating transcriptional responses, but their role in the HBV life cycle is as yet undefined. We demonstrated that histone lysine demethylase 4 (KDM4) can restrict HBV, and pharmacological or oxygen-mediated inhibition of the demethylase increases viral RNAs derived from both episomal and integrated copies of the viral genome. Sequencing studies demonstrated that KDM4 is a major regulator of the hepatic transcriptome, which defines hepatocellular permissivity to HBV infection. We propose a model where HBV exploits cellular oxygen sensors to replicate and persist in the liver. Understanding oxygen-dependent pathways that regulate HBV infection will facilitate the development of physiologically relevant cell-based models that support efficient HBV replication.