HBcAg induces PD-1 upregulation on CD4+T cells through activation of JNK, ERK and PI3K/AKT pathways in chronic hepatitis-B-infected patients

Hepatitis B virus infection and the risk of gynecologic cancers: a systematic review and meta-analysis

OBJECTIVES

The relationship between hepatitis B virus (HBV) infection and gynecologic cancers is controversial. We aimed to evaluate the risk of gynecologic cancers associated with HBV infection using a meta-analysis.

METHODS

Two independent reviewers identified publications in the PubMed, Embase and Cochrane Library databases that reported an association between HBV and the risk of gynecologic malignancy from inception to December 31, 2022. The Newcastle-Ottawa Scale (NOS) was used to evaluate the quality of the included articles. Pooled odds ratios (ORs) and 95% corresponding confidence intervals (CIs) were calculated using a fixed effects model or random effects model.

RESULTS

We collected data from 7 studies that met the inclusion criteria, including 2 cohort studies and 5 case-control studies. HBV was significantly associated with the risk of cervical cancer in the general population (OR 1.22, 95% CI 1.09-1.38, P = 0.001), although the same trend was not found in endometrial cancer (OR 1.30, 95% CI 0.95-1.77, P = 0.105) and ovarian cancer (OR 1.03, 95% CI 0.79-1.35, P = 0.813). Subgroup analysis showed that HBV infection was positively associated with the risk of cervical cancer (OR 1.27, 95% CI 1.13-1.44, P = 0.000) in case-control studies. Asian women infected with HBV have a significantly increased risk of cervical cancer (OR 1.24, 95% CI 1.10-1.40, P = 0.001) and endometrial cancer (OR 1.46, 95% CI 1.07-1.99, P = 0.018). Hospital-based studies were found to be associated with an increased risk of cervical cancer (OR 1.30, 95% CI 1.14-1.47, P = 0.000) and endometrial cancer (OR 1.61, 95% CI 1.04-2.49, P = 0.032). The results of Begg's and Egger's tests showed no publication bias.

CONCLUSIONS

This meta-analysis shows a positive association between HBV infection and cervical cancer. HBV is positively correlated with the risk of cervical cancer and endometrial cancer in Asian women and hospital-based populations. More multicenter prospective studies are required to confirm the findings.

Metabolic interventions combined with CTLA-4 and PD-1/PD-L1 blockade for the treatment of tumors: mechanisms and strategies

Immunotherapies based on immune checkpoint blockade (ICB) have significantly improved patient outcomes and offered new approaches to cancer therapy over the past decade. To date, immune checkpoint inhibitors (ICIs) of CTLA-4 and PD-1/PD-L1 represent the main class of immunotherapy. Blockade of CTLA-4 and PD-1/PD-L1 has shown remarkable efficacy in several specific types of cancers, however, a large subset of refractory patients presents poor responsiveness to ICB therapy; and the underlying mechanism remains elusive. Recently, numerous studies have revealed that metabolic reprogramming of tumor cells restrains immune responses by remodeling the tumor microenvironment (TME) with various products of metabolism, and combination therapies involving metabolic inhibitors and ICIs provide new approaches to cancer therapy. Nevertheless, a systematic summary is lacking regarding the manner by which different targetable metabolic pathways regulate immune checkpoints to overcome ICI resistance. Here, we demonstrate the generalized mechanism of targeting cancer metabolism at three crucial immune checkpoints (CTLA-4, PD-1, and PD-L1) to influence ICB therapy and propose potential combined immunotherapeutic strategies co-targeting tumor metabolic pathways and immune checkpoints.

HIV-HBV Coinfection-Current Challenges for Virologic Monitoring

HIV-HBV coinfected patients have higher rates of liver-related morbidity, hospitalizations, and mortality compared to HBV or HIV mono-infected ones. Clinical studies have shown an accelerated progression of liver fibrosis and an increased incidence of HCC, resulting from the combined action of HBV replication, immune-mediated hepatocytolysis, and HIV-induced immunosuppression and immunosenescence. Antiviral therapy based on dually active antiretrovirals is highly efficient, but late initiation, global disparities in accessibility, suboptimal regimens, and adherence issues may limit its impact on the development of end-stage liver disease. In this paper, we review the mechanisms of liver injuries in HIV-HBV coinfected patients and the novel biomarkers that can be used for treatment monitoring in HIV-HBV coinfected persons: markers that assess viral suppression, markers for liver fibrosis evaluation, and predictors of oncogenesis.

Prospects for NK-based immunotherapy of chronic HBV infection

Effective and long-term treatment is required for controlling chronic Hepatitis B Virus (HBV) infection. Natural killer (NK) cells are antiviral innate lymphocytes and represent an essential arm of current immunotherapy. In chronic HBV (CHB), NK cells display altered changes in phenotypes and functions, but preserve antiviral activity, especially for cytolytic activity. On the other hand, NK cells might also cause liver injury in the disease. NK -based immunotherapy, including adoptive NK cell therapy and NK -based checkpoint inhibition, could potentially exploit the antiviral aspect of NK cells for controlling CHB infection while preventing liver tissue damage. Here, we review recent progress in NK cell biology under the context of CHB infection, and discuss potential NK -based immunotherapy strategies for the disease.

Hepatitis B or C viral infection and the risk of cervical cancer

BACKGROUND

The present study aimed to evaluate the effects of hepatitis B virus (HBV) or hepatitis C virus (HCV) infection on the risk of cervical cancer.

METHODS

We conducted a case-control study including 838 cervical cancer cases and 838 benign disease controls matched for age, ethnicity, and place of birth. Venous blood was tested for HBV and HCV serological markers. Multiple odds ratios (OR) and corresponding 95% confidence intervals (CI) for cervical cancer were estimated using logistic regression. HBV antigens were examined using immunohistochemical staining.

RESULTS

Anti-HCV was positive in 10 cases (1.2%) and 0 controls (0%). Cases had higher percentage of chronic HBV infection (HBsAg-positive/anti-HBc-positive) and prior HBV infection (HBsAg-negative/anti-HBc-positive) than controls (6.3% vs 4.4%; 11.6% vs 7.3%). Both chronic HBV infection (OR 1.6; 95% CI 1.0-2.4) and prior HBV infection (OR 1.7; 95% CI 1.2-2.4) were associated with cervical cancer in univariate logistic regression analyses. In subgroup analysis among HPV-positive patients, the association between chronic HBV infection and cervical cancer disappeared (OR 1.2; 95% CI 0.4-3.4); while in subgroup among patients younger than 50 years, the association remained significant with adjustment for HPV infection and parity (adjusted OR 2.1; 95% CI 1.0-4.4). HBsAg and HBcAg were detected in 8% and 12% of cervical cancer cases who had seropositive HBsAg, respectively. Compared with the benign controls, individuals with both HBsAg and HPV positive had an increased risk of cervical cancer (adjusted OR 67.1; 95% CI 23.4-192.7).

CONCLUSIONS

HBV infection was associated with cervical cancer in patients with age younger than 50 years. Further prospective studies are needed to confirm this relationship.

Innate and adaptive immune escape mechanisms of hepatitis B virus

Chronic hepatitis B virus (HBV) infection is an international health problem with extremely high mortality and morbidity rates. Although current clinical chronic hepatitis B (CHB) treatment strategies can partly inhibit and eliminate HBV, viral breakthrough may result due to non-adherence to treatment, the emergence of viral resistance, and a long treatment cycle. Persistent CHB infection arises as a consequence of complex interactions between the virus and the host innate and adaptive immune systems. Therefore, understanding the immune escape mechanisms involved in persistent HBV infection is important for designing novel CHB treatment strategies to clear HBV and achieve long-lasting immune control. This review details the immunological and biological characteristics and escape mechanisms of HBV and the novel immune-based therapies that are currently used for treating HBV.

Potential Biomarkers for the Efficacy of PD-1-PD-L Blockade in Cancer

A decade ago, immune checkpoint blockade emerged as a major breakthrough in oncology, proposing a novel approach by which immune brakes could be released to enhance antitumor responses. Despite apparently modest improvement of the median duration of response, a spectacular doubling of long-term responses as compared to the available standard of care was seen, for instance, in metastatic melanoma. It soon became obvious that the percentage of patients responding to these novel approaches is relatively small, and the importance of an accurate prediction of responders became more and more clear. Strong predictive markers would allow for the administration of immune checkpoint blocker therapy to the patients most likely to benefit from it, and sparing the potential non-responders of a treatment which is far from innocuous, being associated with significant side-effects and, not least, an important price tag. A number of potential response predictors have already been investigated and partly validated, but they do not cover the major unmet need encountered in the current clinical setting. Here, we review biomarkers for immune checkpoint blockade efficacy, either clinically validated and currently in use, or which have been proposed as candidates and are currently under investigation.

The Functions of Hepatitis B Virus Encoding Proteins: Viral Persistence and Liver Pathogenesis

About 250 million people worldwide are chronically infected with Hepatitis B virus (HBV), contributing to a large burden on public health. Despite the existence of vaccines and antiviral drugs to prevent infection and suppress viral replication respectively, chronic hepatitis B (CHB) cure remains a remote treatment goal. The viral persistence caused by HBV is account for the chronic infection which increases the risk for developing liver cirrhosis and hepatocellular carcinoma (HCC). HBV virion utilizes various strategies to escape surveillance of host immune system therefore enhancing its replication, while the precise mechanisms involved remain elusive. Accumulating evidence suggests that the proteins encoded by HBV (hepatitis B surface antigen, hepatitis B core antigen, hepatitis B envelope antigen, HBx and polymerase) play an important role in viral persistence and liver pathogenesis. This review summarizes the major findings in functions of HBV encoding proteins, illustrating how these proteins affect hepatocytes and the immune system, which may open new venues for CHB therapies.

Transcriptome alterations in HepG2 cells induced by shRNA knockdown and overexpression of TMEM2 gene

Transmembrane 2 (TMEM2) gene inhibits chronic hepatitis-B virus (HBV) infection, while the underlying molecular mechanisms remain unknown. Transcriptome alterations in HepG2 cells following TMEM2 overexpression or silencing by shRNA were analyzed by next-generation sequencing. Both overexpression and knockdown of the TMEM2 gene caused wide-spread changes in gene expression in HepG2 cells. Differentially expressed genes caused by altered TMEM2 gene expression were associated with multiple biological processes linked with viral infection and various signaling pathways. KEGG analysis revealed that many of the differentially expressed genes were enriched in the PI3K/AKT signaling pathway. Moreover, we show that genes related to the PI3K/AKT signaling pathway, such as SYK, FLT4, AKT3, FLT1, and IL6, are biological targets regulated by TMEM2 in HepG2 cells. This is the first transcriptome-wide study in which TMEM2-regulated genes in HepG2 cells have been screened. Our findings elucidate the molecular events associated with TMEM2-mediated hepatocyte pathogenesis in chronic HBV infection.

Programmed cell death protein 1 promotes hepatitis B virus transmission through the regulation of ERK1/2-mediated trophoblasts differentiation

PURPOSE

The purpose of our research is to evaluate the mechanism of PD-1 in the promotion of HBV transmission.

METHODS

HBV was used to infect two human choriocarcinoma cell line, including JEG-3, as well as BeWo. We used PCR and western blotting to detect PD-1 gene and protein expression levels in cells. Stable knockdown of the PD-1 gene in JEG-3 cells was obtained by lentiviral transfection. Trophoblast cell proliferation was evaluated using CCK8 and flow cytometry. The concentration of HBV antibody in the cell supernatant was measured by ELISA. DNA was then extracted from the cells and the copy number of the HBV virus was detected by PCR. Finally, ERK1/2 expression was detected by western blot.

RESULTS

High PD-1 gene expression in HBV-infected trophoblasts and the knockdown of PD-1 gene can, respectively, improve the proliferation of HBV-infected trophoblasts and reduce viral replication in trophoblasts. In addition, PD-1 and ERK1/2 proteins were co-expressed in HBV-infected trophoblasts and inhibited the activation of ERK1/2 pathway in HBV-infected trophoblasts. ERK1/2 expression significantly increased after PD-1 knockdown. Therefore, PD-1 might be an important protein in trophoblast cells infected with HBV.

CONCLUSIONS

PD-1 promoted HBV transmission through regulating ERK1/2-mediated trophoblasts differentiation. Therefore, our research may provide new ideas and methods for preventing mother-to-child transmission of HBV infection during pregnancy.

HoxA10 Facilitates SHP-1-Catalyzed Dephosphorylation of p38 MAPK/STAT3 To Repress Hepatitis B Virus Replication by a Feedback Regulatory Mechanism

Hepatitis B virus (HBV) infection is the leading cause of chronic hepatitis B (CHB), liver cirrhosis (LC), and hepatocellular carcinoma (HCC). This study reveals a distinct mechanism underlying the regulation of HBV replication. HBV activates homeobox A10 (HoxA10) in human hepatocytes, leukocytes, peripheral blood mononuclear cells (PBMCs), HepG2-NTCP cells, leukocytes isolated from CHB patients, and HBV-associated HCC tissues. HoxA10 in turn represses HBV replication in human hepatocytes, HepG2-NTCP cells, and BALB/c mice. Interestingly, we show that during early HBV infection, p38 mitogen-activated protein kinase (MAPK) and signal transducer and activator of transcription 3 (STAT3) were activated to facilitate HBV replication; however, during late HBV infection, HoxA10 was induced to attenuate HBV replication. Detailed studies reveal that HoxA10 binds to p38 MAPK, recruits SH2-containing protein tyrosine phosphatase 1 (SHP-1) to facilitate SHP-1 in catalyzing dephosphorylation of p38 MAPK/STAT3, and thereby attenuates p38 MAPK/STAT3 activation and HBV replication. Furthermore, HoxA10 binds to the HBV enhancer element I (EnhI)/X promoter, competes with STAT3 for binding of the promoter, and thereby represses HBV transcription. Taken together, these results show that HoxA10 attenuates HBV replication through repressing the p38 MAPK/STAT3 pathway by two approaches: HoxA10 interacts with p38 MAPK and recruits SHP-1 to repress HBV replication, and HoxA10 binds to the EnhI/X promoter and competes with STAT3 to attenuate HBV transcription. Thus, the function of HoxA10 is similar to the action of interferon (IFN) in terms of inhibition of HBV infection; however, the mechanism of HoxA10-mediated repression of HBV replication is different from the mechanism underlying IFN-induced inhibition of HBV infection.IMPORTANCE Two billion people have been infected with HBV worldwide; about 240 million infected patients developed chronic hepatitis B (CHB), and 650,000 die each year from liver cirrhosis (LC) or hepatocellular carcinoma (HCC). This work elucidates a mechanism underlying the control of HBV replication. HBV infection activates HoxA10, a regulator of cell differentiation and cancer progression, in human cells and patients with CHB and HCC. HoxA10 subsequently inhibits HBV replication in human tissue culture cells and mice. Additionally, HoxA10 interacts with p38 MAPK to repress the activation of p38 MAPK and STAT3 and recruits and facilitates SHP-1 to catalyze the dephosphorylation of p38 MAPK and STAT3. Moreover, HoxA10 competes with STAT3 for binding of the HBV X promoter to repress HBV transcription. Thus, this work reveals a negative regulatory mechanism underlying the control of HBV replication and provides new insights into the development of potential agents to control HBV infection.

HBV and HIV/HBV Infected Patients Have Distinct Immune Exhaustion and Apoptotic Serum Biomarker Profiles

Background:

Hepatitis B virus (HBV) infection is a leading cause of chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma worldwide. Due to their shared routes of transmission, approximately 10% of HIV-infected patients worldwide are chronically coinfected with HBV. Additionally, liver disease has become a major cause of morbidity and mortality in HBV/HIV coinfected patients due to prolonged survival with the success of antiretroviral therapy. The relationship between immune exhaustion markers (PD-1/PD-L1) and apoptotic markers such as Fas/FasL, TGFβ1, TNF-α, and Th1/Th2 cytokines are not clearly delineated in HBV/HIV coinfection.

Methods:

Levels of soluble Fas/FasL, TGFβ1, TNF-α, and sPD-1/sPD-L1 as well as Th1 and Th2 cytokines were evaluated in the sera of HBV-monoinfected (n = 30) and HBV/HIV-coinfected (n = 15) patients and compared to levels in healthy controls (n = 20).

Results:

HBV-monoinfected patients had significantly lower levels of the anti-inflammatory cytokine IL-4 (P < 0.05) and higher levels of apoptotic markers sFas, sFasL, and TGFβ-1 (P < 0.001) compared to healthy controls. Coinfection with HIV was associated with higher levels of sFas, TNF-α, and sPD-L1 (P < 0.005), and higher levels of the pro-inflammatory cytokines IL-6, IL-8, and IL-12p70 (P < 0.05) compared to healthy controls. Patients with HBV infection had a unique biomarker clustering profile comprised of IFN-γ, IL12p70, IL-10, IL-6, and TNF-α that was distinct from the profile of the healthy controls, and the unique HIV/HBV profile comprised GM-CSF, IL-4, IL-2, IFN-γ, IL12p70, IL-7, IL-10, and IL-1β. In HBV monoinfection a significant correlation between sFasL and PD1(r = 0.46, P = < 0.05) and between sFas and PDL1 (r = 0.48, P = <0.01) was observed.

Conclusion:

HBV-infected and HBV/HIV-coinfected patients have unique apoptosis and inflammatory biomarker profiles that distinguish them from each other and healthy controls. The utilization of those unique biomarker profiles for monitoring disease progression or identifying individuals who may benefit from novel immunotherapies such as anti-PD-L1 or anti-PD-1 checkpoint inhibitors appears promising and warrants further investigation.

CTLA‑4 interferes with the HBV‑specific T cell immune response (Review)

Hepatitis B virus (HBV) infection is a major cause of hepatic inflammation. Successful HBV clearance in patients is associated with sustained viral control by effector T cells. Compared with acute hepatitis B, chronic HBV infection is associated with the depletion of T cells, resulting in weak or absent virus-specific T cells reactivity, which is described as 'exhaustion'. This exhaustion is characterized by impaired cytokine production and sustained expression of multiple coinhibitory molecules. Cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) is one of many coinhibitory molecules that can attenuate T cell activation by inhibiting costimulation and transmitting inhibitory signals to T cells. Persistent HBV infection results in the upregulation of CTLA-4 on hepatic CD8⁺ T cells. This prompts CD8⁺ T cell apoptosis, and the activation of cytotoxic T lymphocytes is blocked. Similar to CD8⁺ T cells, CD4⁺ T helper (Th) cell proliferation is hindered following CTLA-4 upregulation. In addition, the differentiation of CD4⁺ Th is polarized toward the Th2/peripherally-inducible T regulatory cell types, increasing the levels of anti-inflammatory cytokines. Conversely, the activation of proinflammatory cells (Th1 and follicular helper T) is blocked, and the levels of proinflammatory cytokines decline. This review summarizes the current literature relevant to T cell exhaustion in patients with HBV-related chronic hepatitis, and discusses the roles of CTLA-4 in T cell exhaustion.

Immunomodulatory effects of Tim-3 and PD-1 on chronic hepatitis B virus infection

In patients with chronic hepatitis B virus (HBV) infection, the immune cells are dysfunctional, and the immune function cannot work normally. T-cell immunoglobulin mucin-3 (Tim-3) and programmed death receptor-1 (PD-1) are overexpressed on the surface of immune cells, such as cluster of differentiation (CD)4+, CD8+ T-lymphocytes, and natural killer (NK) cells. Many studies indicate that this phenomenon is closely related to the persistence, occurrence, development, and prognosis of HBV. Tim-3 and PD-1 may be used as new immune targets for the treatment of chronic hepatitis B.

Hepatitis B virus infection is associated with younger median age at diagnosis and death in cancers

Several non-hepatocellular cancers were linked with hepatitis B virus (HBV) infection. This study was aimed to quantify the potential associations between HBV infection and multiple non-hepatocellular cancers. Continuous cases, including 5,715 non-cancer and 40,963 cancer cases diagnosed from 2008 to 2014 in Sun Yat-sen University Cancer Center were analyzed. HBV DNA and hepatitis B core antigen (HBcAg) were examed in gastric cancer tissues by polymerase chain reaction and immunohistochemical staining. After adjusting for age, sex, year of diagnosis, smoking, drinking and family history of cancer, significant associations were found between serum HBsAg and frequently reported HBV-related non-hepatocellular cancers, including non-Hodgkin's lymphoma, cholangiocarcinoma and pancreatic cancer [adjusted odds ratio (AOR) and 95% confidence interval (CI): 1.89 (1.65-2.16)], as well as total other non-hepatocellular cancers [AOR and 95% CI: 1.12 (1.03-1.22)]. The median ages at diagnosis, all-cause death and cancer-specific death of serum HBsAg positive cancer patients were all significantly younger than those with serum HBsAg negative. HBV DNA was detected in 12.4% (34/275) gastric cancer tissues and HBcAg was most commonly detected in lymphocytes. This was the first report that HBV infection had a modest but significant nonspecific association with total non-hepatocellular cancers. Median age at diagnosis and death was significantly younger in serum HBsAg positive cancer patients. The underlying mechanism needs further investigation.

Attenuation of lymphocyte immune responses during Mycobacterium avium complex-induced lung disease due to increasing expression of programmed death-1 on lymphocytes

Mycobacterium avium complex-induced lung disease (MAC-LD) becomes important due to its increasing prevalence. Attenuated cellular immunity associated with programmed cell death (PD)-1 may play a pathophysiological role in MAC-LD but lacks of investigation. We enrolled 80 participants in this prospective study, including 50 with MAC-LD and 30 healthy controls. Peripheral blood mononuclear cells (PBMCs), lymphocytes and monocyte-derived macrophages were used for MAC antigen stimulation. Patients with MAC-LD had lower tumor necrosis factor-α and interferon-γ responses compared to the healthy controls in PBMC stimulation assays with MAC bacilli. These responses improved after MAC treatment. The PD-1 and PD ligand expressions and apoptosis were higher in the lymphocytes of the patients with MAC-LD compared to the controls. Both PD-1 and apoptosis on T lymphocytes were significantly increased in the patients with MAC-LD, either by direct MAC stimulation or by MAC-primed macrophage activation. Partially blocking PD-1 and the PD ligand with antagonizing antibodies in the stimulation assay significantly increased the cytokine production of IFN-γ and decreased the apoptosis on T lymphocytes. In conclusion, the patients with MAC-LD have attenuated lymphocyte immunity, which might be associated with increasing activation of PD-1 and PD-1 ligand. Regulating such activation might improve the lymphocytic secretion of IFN-γ and reduce apoptosis.

T cells in chronic lymphocytic leukemia display dysregulated expression of immune checkpoints and activation markers

Chronic lymphocytic leukemia is characterized by impaired immune functions largely due to profound T-cell defects. T-cell functions also depend on co-signaling receptors, inhibitory or stimulatory, known as immune checkpoints, including cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) and programmed death-1 (PD-1). Here we analyzed the T-cell phenotype focusing on immune checkpoints and activation markers in chronic lymphocytic leukemia patients (n=80) with different clinical characteristics and compared them to healthy controls. In general, patients had higher absolute numbers of CD3⁺ cells and the CD8⁺ subset was particularly expanded in previously treated patients. Progressive patients had higher numbers of CD4⁺ and CD8⁺ cells expressing PD-1 compared to healthy controls, which was more pronounced in previously treated patients (P=0.0003 and P=0.001, respectively). A significant increase in antigen-experienced T cells was observed in patients within both the CD4⁺ and CD8⁺ subsets, with a significantly higher PD-1 expression. Higher numbers of CD4⁺ and CD8⁺ cells with intracellular CTLA-4 were observed in patients, as well as high numbers of proliferating (Ki67⁺) and activated (CD69⁺) CD4⁺ and CD8⁺ cells, more pronounced in patients with active disease. The numbers of Th1, Th2, Th17 and regulatory T cells were substantially increased in patients compared to controls (P<0.05), albeit decreasing to low levels in pre-treated patients. In conclusion, chronic lymphocytic leukemia T cells display increased expression of immune checkpoints, abnormal subset distribution, and a higher proportion of proliferating cells compared to healthy T cells. Disease activity and previous treatment shape the T-cell profile of chronic lymphocytic leukemia patients in different ways.

Hepatitis B core antigen upregulates B7-H1 on dendritic cells by activating the AKT/ERK/P38 pathway: a possible mechanism of hepatitis B virus persistence

B7-H1 binding to programmed death-1 may deliver a coinhibitory signal to T cells that is involved in the regulation of T-cell activation and tolerance. B7-H1 plays a key role in dysfunction of dendritic cells (DCs) during chronic HBV infection, but the expression mechanism of B7-H1 remains unclear. One hundred and twenty-nine patients with chronic HBV infection were categorized into either the immune tolerance phase (HBV-IT), the immune clearance phase (HBV-IC), or the inactive carrier phase (HBV-IA). Twenty healthy volunteers were enrolled as controls. Another 16 patients with HBeAg-positive chronic Hepatitis B were enrolled, and entecavir was administrated at 0.5 mg per day for 6 months. The B7-H1 expression level on peripheral DCs was tested by flow cytometry. In vitro, expression levels of B7-H1 and signaling molecules on monocyte-derived DC (MO-DC) induced by recombinant hepatitis B virus C antigen (rhHBcAg) were examined by RT-PCR, flow cytometry, and western blotting, and the apoptosis rate was tested by flow cytometry. The percentages of peripheral DCs and myeloid DCs (mDCs) were decreased and B7-H1 levels were increased in patients compared with controls. Serum HBV-DNA levels were positively correlated with B7-H1 levels on mDCs in patients with HBV-IT. B7-H1 levels on peripheral DCs from patients with chronic hepatitis B decreased after antiviral therapy. In vitro studies demonstrated that the B7-H1 level on MO-DC was upregulated by rhHBcAg, which resulted from the activation of PI3K-AKT, ERK, and P38 signaling pathways, and the percentage of MO-DC was downregulated by rhHBcAg. In addition, rhHBcAg promoted the apoptosis of MO-DC. The data suggest that HBcAg induced B7-H1 upregulation by activating AKT, ERK, and P38 signaling pathways, which inhibited the clearance of HBV-DNA and the reduction of DCs contributed to immune tolerance, which may correlate with apoptosis.

CD28 family of receptors on T cells in chronic HBV infection: Expression characteristics, clinical significance and correlations with PD-1 blockade

The aim of the present study was to investigate the overall clinical expression characteristics of the cluster of differentiation (CD)28 family receptors [CD28, inducible T-cell co-stimulator, programmed cell death protein 1 (PD-1), cytotoxic T-lymphocyte-associated protein 4 and B- and T-lymphocyte attenuator] on T cells in patients with chronic hepatitis B (CHB), analyze the correlations among these receptors and the clinical parameters, and to investigate the effects of PD-1 blockade on the receptor expression profiles, T-cell function and other biological effects. The expression characteristics of the CD28 family of receptors, the effects of PD-1 blockade on the receptor expression profiles and the levels of interferon (IFN)-γ were investigated in the T cells of patients with CHB. In addition, the transcription factor, T-box 21 (T-bet) and GATA binding protein 3 (GATA-3) mRNA expression levels were investigated in the peripheral blood mononuclear cells (PBMCs) of patients with CHB. The expression levels of the CD28 family receptors in the T cells of patients with CHB demonstrated distinct characteristics, for example levels of PD-1 and CTLA-4 on CD4 T cells and ICOS, PD-1, and BTLA on CD8 T cells were increased in cells from patients with CHB compared with those from the healthy individuals. A significant positive correlation was demonstrated among the serum HBV DNA titers and the levels of PD-1 on CD8⁺ T cells with the highest expression of PD-1 corresponding to viral levels >10⁶ IU/ml. A significant positive correlation was observed between the serum HBV DNA titers and the expression levels of BTLA on CD8⁺ T cells with the highest expression of BTLA corresponding to viral levels >10⁶ IU/ml. PD-1 blockade altered the expression profiles of CD28 family receptors in the T cells of patients with CHB, partly enhanced T cell function and increased the ratio of T-bet/GATA-3 mRNA in PBMCs. Thus, CD28 family receptors are potential clinical indicators for the rapid monitoring of changes in T cell function during CHB treatment. Furthermore, PD-1 blockade has a therapeutic potential that may be enhanced by modulating the expression of co-stimulatory and -inhibitory receptors of the CD28 family.

microRNA-4717 differentially interacts with its polymorphic target in the PD1 3' untranslated region: A mechanism for regulating PD-1 expression and function in HBV-associated liver diseases

Programmed cell death-1 (PD-1) is involved in hepatitis B virus (HBV) infection, the leading cause of hepatocellular carcinoma (HCC) worldwide. Single-nucleotide polymorphism, rs10204525, located in the PD1 3' untranslated regions (UTR), is associated with chronic HBV infection. MicroRNAs (miRNAs) regulate gene expression via specific binding to the target 3'UTR of mRNA. In this study, three miRNAs were predicted to putatively interact with PD1 rs10204525 polymorphic site of allele G. One of them, miRNA-4717, was demonstrated to allele-specifically affect luciferase activity in a dose-dependent manner in cells transfected with vectors containing different rs10204525 alleles. In lymphocytes from chronic HBV patients withrs10204525 genotype GG, miR-4717 mimics significantly decreased PD-1 expression and increased (TNF)-α and interferon (IFN)-γ production. miR-4717 inhibitor significantly increased PD-1 expression and decreased TNF-α and IFN-γ production although not significantly. In lymphocytes from chronic HBV patients with rs10204525 genotype AA, no similar effects were observed. miR-4717 levels in peripheral lymphocytes from patients with HBV-related chronic hepatitis, cirrhosis and HCC were significantly decreased. In conclusion, miR-4717 may allele-specifically regulate PD-1 expression through interaction with the 3' UTR of PD1 mRNA, leading to the alteration of immune regulation and affecting the susceptibility and disease course of chronic HBV infection.

Screening of differentially expressed genes in chronic hepatitis B patients and prediction of related biological pathways

AIM: To study the molecular mechanism of pathogenesis of chronic hepatitis B.

METHODS: Based on microarray experiment, GeneSpring software was used to screen differentially expressed genes in chronic hepatitis B patients, and GeneTrail software was used to perform enrichment analysis of related biological pathways.

RESULTS: A total of 417 differentially expressed genes were identified, of which 205 were upregulated and 212 downregulated. Significant pathways to which downregulated genes belong include ErbB, non-small cell lung cancer, mTOR, RNA degradation, T cell receptor, chronic myeloid leukemia, and renal cell carcinoma pathways. Significant pathways to which upregulated genes belong include chemokine, lysosomes, Vibrio cholerae infection, and IgG Fc receptor-mediated phagocytosis pathways.

CONCLUSION: PI3K/AKT downregulation is likely a major molecular mechanism of persistent hepatitis B.

Enhanced hepatitis B virus (HBV) pre-genomic RNA levels and higher transcription efficiency of defective HBV genomes

Defective hepatitis B virus (dHBV) particles contain genomes corresponding to singly spliced HBV RNA. A limited number of studies show that dHBV is present in all chronically HBV-infected patients. Clinical studies have linked dHBV and dHBV gene products to high virus loads and liver damage. The replication characteristics of dHBV genomes remain poorly understood. We found that the splice donor/acceptor sites critical for the formation of dHBV genomes are conserved across HBV genotypes. We report a novel method to create dHBV constructs from corresponding wild-type (WT) HBV constructs. We assessed the transcriptional characteristics of the dHBV constructs with those of the corresponding WT construct using a cell culture model. Interestingly, dHBV constructs had higher pre-genomic RNA levels, transcription efficiency, HBV e antigen levels and intracellular HBV core antigen levels compared with the corresponding WT HBV constructs. Our findings highlight previously unrecognized fundamental molecular characteristics of dHBV genomes and their potential role in the pathogenesis of HBV infection.

PD-1 mRNA expression is associated with clinical and viral profile and PD1 3'-untranslated region polymorphism in patients with chronic HBV infection

Programmed cell death-1 (PD-1) is involved in hepatitis B virus (HBV) infection and single-nucleotide polymorphism (SNP) rs10204525 in the 3'-untranslated region (3' UTR) of PD1 gene was shown to be associated with the disease course of HBV infection. This study examined the associations of PD-1 mRNA expression with the clinical and viral profiles and the genotypes of rs10204525 in HBV infection. PD-1 mRNA levels in peripheral blood nuclear cells were determined by real-time quantitative reverse transcription polymerase chain reaction (PCR). PD1 rs10204525 was genotyped by bidirectional PCR amplification of specific alleles. The results showed that patients with chronic HBV infection had significantly elevated PD-1 mRNA levels than healthy controls. Patients with chronic hepatitis and hepatocellular carcinoma had significantly higher PD-1 mRNA levels than healthy controls. HBeAg (+) patients had significantly higher PD-1 mRNA levels than HBeAg (-) patients (P<0.001). PD-1 mRNA levels were sequentially increased with the elevation of HBV DNA levels. In HBV patients, but not in healthy controls, PD-1 mRNA levels were sequentially decreased from rs10204525 genotypes AA, AG to GG and the levels in genotype AA were significantly higher than in genotype GG (P=0.039). These findings suggest that increased PD-1 expression may affect the disease course of chronic HBV infection by facilitating HBV viral replication, and this may at least partially relate to PD1 3' UTR polymorphism.

Beneficial therapeutic effect of Chinese herbal Bushen formula on CHB patients with mildly elevated alanine aminotransferase by down-regulating CD4+CD25+T cells

ETHNOPHARMACOLOGICAL RELEVANCE

To investigate the clinical effects of the Bushen formula on chronic hepatitis B (CHB) patients with mildly elevated alanine aminotransferase (ALT) (1-2 times ULN) and its relevant immune mechanism.

MATERIALS AND METHODS

Fifty CHB patients were enrolled, and they were categorized into two groups according to infection state, including CHB carrier group(24 patients) and mildly elevated ALT (1-2 times ULN) group (26 patients), and 12 healthy volunteers were collected as normal control group. In addition, patients with mildly elevated ALT were taking the Bushen formula for 6 months. Biochemical assessment, viral load quantitation and HBV markers were examined at the Department of Clinical Laboratory, Shanghai Shuguang Hospital. Peripheral blood mononuclear cells were separated from patients and healthy volunteers. T cells were separated from healthy blood, and Hepatitis B core antigen (HBcAg) was added to the culture media. The percentage of CD4+CD25+T cells and the expression levels of IFN-γ and IL-4 were examined by flow cytometry and the expression level of FoxP3 was examined by real-time PCR and flow cytometry. The Chinese medicine symptom complex score was calculated.

RESULTS

The percentage of CD4+CD25+T cells and the expression level of Foxp3 in two CHB patient groups were higher than that in the normal control group, and the percentage of CD4+CD25+T cells and the expression level of Foxp3 in the CHB carrier group were highest. The experiment in vitro showed that both the percentage of CD4+CD25+T cells and the expression of Foxp3 were elevated by HBcAg in CD4+T cells separated from normal peripheral blood. In patients with mildly elevated ALT, the serum ALT level was significantly decreased from 81.77±18.24U/L to 64.92±20.60U/L and the serum HBV DNA level was significantly decreased from 6.54±0.95 (log) to 5.15±2.22 (log), and symptom scores were significantly decreased from 6.19±3.99 to 2.77±1.66 after administration of the Bushen formula. In addition, we found that the frequency of CD4+CD25+T cells correlated negatively with the expression level of IFN-γ in CD4+T cells from CHB patients with mildly elevated ALT, and the percentage of CD4+CD25+T cells was decreased from 11.07±4.30% to 8.70±3.49% and the expression level of IFN-γ in CD4+T cells was increased from 13.98±3.25% to 15.85±3.43% after administration of the Bushen formula.

CONCLUSION

In CHB patients, the percentage of CD4+CD25+T cells and the expression of Foxp3 in peripheral blood were increased, which can be repeated in HBcAg-stimulated healthy CD4+T cells. The Bushen formula has positive effects on CHB patients with mildly elevated ALT (1-2 times ULN) by reducing serum ALT and HBV DNA levels, which is relevant with the decreasing of the percentage of CD4+CD25+T cells and the increasing of the expression level of IFN-γ in CD4+T cells.

The PD-1/PD-L1 axis contributes to T-cell dysfunction in chronic lymphocytic leukemia

Chronic lymphocytic leukemia is marked by profound defects in T-cell function. Programmed death-1 is a receptor involved in tumor-mediated immunosuppression through binding of the PD-L1 ligand. Multiparametric flow cytometry and immunohistochemistry were used to study PD-1/PD-L1 expression. Functional assays were used to determine the involvement of the PD-1/PD-L1 axis in T-cell responses. PD-1 expression by CD4(+) and CD8(+) T lymphocytes was significantly higher in 117 chronic lymphocytic leukemia patients than in 33 donors of a comparable age. CD4(+) and CD8(+) T lymphocytes from chronic lymphocytic leukemia patients displayed increased numbers of effector memory and terminally differentiated cells, respectively, when compared to controls. The number of effector memory CD4(+) and terminally differentiated CD8(+) lymphocytes positively associated with a more advanced stage of disease, treatment requirements and unfavorable genomic aberrations. Furthermore, leukemic lymphocytes expressed higher levels of PD-L1 than circulating B lymphocytes from normal donors. PD-1 and PD-L1 surface expression spiked in proliferating T and B lymphocytes, suggesting that this interaction works efficiently in activated environments. Within chronic lymphocytic leukemia proliferation centers in the lymph node, CD4(+)/PD-1(+) T lymphocytes were found to be in close contact with PD-L1(+) chronic lymphocytic leukemia cells. Lastly, functional experiments using recombinant soluble PD-L1 and blocking antibodies indicated that this axis contributes to the inhibition of IFN-γ production by CD8(+) T cells. These observations suggest that pharmacological manipulation of the PD-1/PD-L1 axis may contribute to restoring T-cell functions in the chronic lymphocytic leukemia microenvironment.

Glycyrrhizin regulates CD4+T cell response during liver fibrogenesis via JNK, ERK and PI3K/AKT pathway

The aims of this study were to elucidate the immunomodulatory effects of glycyrrhizin (GL) on CD4(+)T cell responses during liver fibrogenesis. To obtain in vivo evidence about the effects of GL on CD4(+)T cells in livers and spleens of concanavalin A (ConA)-induced mouse model, mice were administrated with ConA together with or without GL for 8 weeks. Mice treated with GL dramatically prevented liver inflammation and fibrosis. Besides, GL inhibited the infiltration of T helper (Th) cell type 1, Th2, Th17 and regulatory T cells (Treg) in livers and spleens of mouse fibrosis models, and regulated the Th1/Th2 and Treg/Th17 balances respectively to a relative dominance of Th1 and Treg lineages in livers. Moreover, GL dramatically enhanced the antifibrotic cytokine interferon (IFN)-γ and interleukin (IL)-10. GL at a concentration of 10 or 100 μg/mL was respectively incubated with ConA-stimulated splenic CD4(+)T cells in vitro, and JNK inhibitor (SP600125), ERK inhibitor (U0126), p38 inhibitor (SB203580) or PI3K/AKT inhibitor (LY29400225) was added during the incubation. Notably, GL not only inhibited ConA-induced proliferation of splenic CD4(+)T cells but also enhanced the mRNAs of IFN-γ and IL-10 in these cells. Be similar to the effects of GL, SP600125, U0126 and LY29400225, however not SB203580, also inhibited ConA-induced CD4(+)T cell proliferation, indicating the involvement of JNK, ERK and PI3K/AKT in this process. Moreover, GL significantly inhibited ConA-induced phosphorylation of JNK, ERK and PI3K/AKT in vitro. Collectively, GL might alleviate liver injury and fibrosis progression via regulation of CD4(+)T cell response in JNK, ERK and PI3K/AKT-dependent pathways.