Interleukin-17 signaling in inflammatory, Kupffer cells, and hepatic stellate cells exacerbates liver fibrosis in mice

BACKGROUND & AIMS

Interleukin (IL)-17 signaling has been implicated in lung and skin fibrosis. We examined the role of IL-17 signaling in the pathogenesis of liver fibrosis in mice.

METHODS

Using cholestatic and hepatotoxic models of liver injury, we compared the development of liver fibrosis in wild-type mice with that of IL-17RA(-/-) mice and of bone marrow chimeric mice devoid of IL-17 signaling in immune and Kupffer cells (IL-17RA(-/-) to wild-type and IL-17A(-/-) to wild-type mice) or liver resident cells (wild-type to IL-17RA(-/-) mice).

RESULTS

In response to liver injury, levels of Il-17A and its receptor increased. IL-17A increased appeared to promote fibrosis by activating inflammatory and liver resident cells. IL-17 signaling facilitated production of IL-6, IL-1, and tumor necrosis factor-α by inflammatory cells and increased the expression of transforming growth factor-1, a fibrogenic cytokine. IL-17 directly induced production of collagen type I in hepatic stellate cells by activating the signal transducer and activator of transcription 3 (Stat3) signaling pathway. Mice devoid of Stat3 signaling in hepatic stellate cells (GFAPStat3(-/-) mice) were less susceptible to fibrosis. Furthermore, deletion of IL-23 from immune cells attenuated liver fibrosis, whereas deletion of IL-22 exacerbated fibrosis. Administration of IL-22 and IL-17E (IL-25, a negative regulator of IL-23) protected mice from bile duct ligation-induced liver fibrosis.

CONCLUSIONS

IL-17 induces liver fibrosis through multiple mechanisms in mice. Reagents that block these pathways might be developed as therapeutics for patients with cirrhosis.

Methylation of the glutathione-S-transferase M3 gene promoter is associated with oxidative stress in acute-on-chronic hepatitis B liver failure

Chronic hepatitis B (CHB) is a major cause for liver disease worldwide, ranking as the first cause for liver cirrhosis and hepatocellular carcinoma. Acute-on-chronic hepatitis B liver failure (ACHBLF) is most commonly caused by acute severe exacerbation during CHB virus infection. The pathophysiology of ACHBLF is still poorly understood. Glutathione-S-transferase (GST) M3 belongs to GSTs superfamily and it has been demonstrated to contribute to oxidative stress-mediated liver damage. The present study was aimed to determine the potential association between GSTM3 promoter methylation and oxidative stress in ACHBLF patients. Thirty ACHBLF patients, 30 CHB patients and 10 healthy controls were included in this study. Methylation of GSTM3 promoter was determined using methylation-specific PCR (MSP) method. Plasma biomarkers for oxidative stress including malondialdehyde (MDA) and GST were detected by enzyme-linked immunosorbent assay (ELISA). Model for end-stage liver disease (MELD) scoring system was used for predicting the severity and prognosis of liver failure. ACHBLF patients had significant higher GSTM3 promoter methylation rate than CHB patients (30% versus 6.7%, χ(2) = 5.455, P = 0.020). Plasma MDA and GST levels were significantly increased in ACHBLF patients compared with CHB patients. Meanwhile, MDA, MELD scores and mortality rate were significantly higher in methylated group than those in unmethylated group of ACHBLF patients. Furthermore, plasma MDA levels were positively correlated with MELD scores of ACHBLF (r = 0.588, P = 0.001). In conclusion, the methylation of GSTM3 promoter may contribute to oxidative stress-associated liver damage and correlate with the disease severity in ACHBLF.

TIPE2 controls innate immunity to RNA by targeting the phosphatidylinositol 3-kinase-Rac pathway

RNA receptors such as TLR3 and retinoid acid-inducible gene I/melanoma differentiation-associated gene 5 play essential roles in innate immunity to RNA viruses. However, how innate immunity to RNAs is controlled at the molecular level is not well understood. We describe in this study a new regulatory pathway of anti-RNA immunity that is composed of PI3K, its target GTPase Rac, and the newly described immune regulator TNF-α-induced protein 8 like-2 (TIPE2, or TNFAIP8L2). Polyinosinic-polycytidylic acid [Poly (I:C)], a dsRNA receptor ligand, activates Rac via its guanine nucleotide exchange factor Tiam; this leads to the activation of cytokine genes and, paradoxically, downregulation of the Tipe2 gene. TIPE2 is a negative regulator of immunity; its deficiency leads to hyperactivation of the PI3K-Rac pathway as exemplified by enhanced AKT, Rac, P21-activated kinase, and IFN regulatory factor 3 activities. As a consequence, TIPE2 knockout myeloid cells are hyperreactive to Poly (I:C) stimulation, and TIPE2 knockout mice are hypersensitive to Poly (I:C)-induced lethality. These results indicate that TIPE2 controls innate immunity to RNA by targeting the PI3K-Rac pathway. Therefore, manipulating TIPE2 or Rac functions can be effective for controlling RNA viral infections.

The expression, function, and clinical relevance of B7 family members in cancer

The modulation and suppression of anti-tumor immune responses is a characteristic feature of tumor cells to escape immune surveillance. Members of the B7 family are involved in this process, since the level of activation of the anti-tumor immune response depends on the balance between co-stimulatory and co-inhibitory signals. Some molecules are often overexpressed in tumors, which has been associated with the pathogenesis and progression of malignancies as well as their immunological and non-immunological functions. The B7 homologs play a key role in the maintenance of self-tolerance and the regulation of both innate and adaptive immunity in tumor-bearing hosts. Furthermore, the blockade of negative signals mediated by the interaction of co-inhibitory ligands and counter-receptors of the B7 family is currently being studied as a potential immunotherapeutic strategy for the treatment of cancer in humans.

Lentiviral vector-mediated down-regulation of IL-17A receptor in hepatic stellate cells results in decreased secretion of IL-6

AIM: To investigate the mechanism of interleukin (IL)-6 secretion through blocking the IL-17A/IL-17A receptor (IL-17RA) signaling pathway with a short hairpin RNA (shRNA) in hepatic stellate cells (HSCs) in vitro.

METHODS: HSCs were derived from the livers of adult male Sprague-Dawley rats. IL-6 expression was evaluated using real-time quantitative polymerase chain reaction and enzyme linked immunosorbent assay. The phosphorylation activity of p38 mitogen activated protein kinases (MAPK) and extracellular regulated protein kinases (ERK) 1/2 upon induction by IL-17A and suppression by IL-17RA shRNA were examined using Western blotting.

RESULTS: IL-6 expression induced by IL-17A was significantly increased compared to control in HSCs (P < 0.01 in a dose-dependent manner). Suppression of IL-17RA using lentiviral-mediated shRNA inhibited IL-6 expression induced by IL-17A compared to group with only IL-17A treatment (1.44 ± 0.17 vs 4.07 ± 0.43, P < 0.01). IL-17A induced rapid phosphorylation of p38 MAPK and ERK1/2 after 5 min exposure, and showed the strongest levels of phosphorylation of p38 MAPK and ERK1/2 at 15 min in IL-17A-treated HSCs. IL-6 mRNA expression induced by IL-17A (100 ng/mL) for 3 h exposure was inhibited by preincubation with specific inhibitors of p38 MAPK (SB-203580) and ERK1/2 (PD-98059) compared to groups without inhibitors preincubation (1.67 ± 0.24, 2.01 ± 0.10 vs 4.08 ± 0.59, P < 0.01). Moreover, Lentiviral-mediated IL-17RA shRNA 1 inhibited IL-17A-induced IL-6 mRNA expression compared to random shRNA in HSCs (1.44 ± 0.17 vs 3.98 ± 0.68, P < 0.01). Lentiviral-mediated IL-17RA shRNA 1 inhibited phosphorylation of p38 MAPK and ERK1/2 induced by 15 min IL-17A (100 ng/mL) exposure.

CONCLUSION: Down-regulation of the IL-17RA receptor by shRNA decreased IL-6 expression induced by IL-17A via p38 MAPK and ERK1/2 phosphorylation in HSCs. Suppression of IL-17RA expression may be a strategy to reduce the inflammatory response induced by IL-17A in the liver.

The evolving story of macrophages in acute liver failure

Acute liver failure (ALF) remains a worldwide problem. The innate immune system acts as an important regulator of ALF. Kupffer cells (KCs), the resident macrophages in liver, play a key role in liver innate immune response. Recent researches have shown that macrophages display a remarkable plasticity and can differentiate into functionally diverse subsets. However, the dynamic polarized phenotypes and functional status of macrophages at different stage of ALF are not clear. In this paper, we present a review of evidence that KCs play a significant role in the pathogenesis of ALF, including the phenotype and functions of macrophages, signaling pathways involved in macrophage functional status and cell-crosstalks of KCs with other immune cells. More information on macrophages will promote a better understanding of the cellular molecular mechanisms of ALF and provide new insights for the development of therapeutic targets for ALF.

The role of innate immunity in HBV infection

Hepatitis B virus (HBV) infection is one of the main causes of chronic liver diseases. Whether HBV infection is cleared or persists is determined by both viral factors and host immune responses. It becomes clear that innate immunity is of importance in protecting the host from HBV infection and persistence. However, HBV develops strategies to suppress the antiviral immune responses. A combined therapeutic strategy with both viral suppression and enhancement of antiviral immune responses is needed for effective long-term clearance and cure for chronic HBV infection. We and others confirmed that bifunctional siRNAs with both gene silencing and innate immune activation properties are beneficial for inhibition of HBV and represent a potential approach for treatment of viral infection. Understanding the nature of liver innate immunity and their roles in chronic HBV progression and HBV clearance may aid in the design of novel therapeutic strategies for chronic HBV infection.

Osteopontin regulates interleukin-17 production in hepatitis

The overexpression of osteopontin is associated with various inflammatory liver diseases. Interestingly, each of these diseases is also associated with IL-17 expression. Therefore, we sought to determine whether there is any mechanistic link between osteopontin and IL-17. Herein we show that IL-17 and osteopontin levels were significantly increased in patients with chronic hepatitis B. We found that IL-17 and osteopontin levels increased similarly in mice with concanavalin A-induced hepatitis. Both osteopontin- and IL-17-deficient mice were resistant to concanavalin A-induced hepatic injury. In addition, osteopontin markedly induced IL-17 expression by leukocytes (from humans and mice). This effect could be blocked by a specific antibody against osteopontin. β3 integrin (one of the osteopontin receptors) was critically involved in the induction of IL-17 production by osteopontin. Osteopontin-induced IL-17 expression was mediated through the p38, JNK, and NF-κB pathways. These findings suggest that osteopontin regulates IL-17 production during the pathogenesis of hepatitis and provide new evidence for the critical roles of osteopontin and IL-17 in hepatitis.

Increased frequency of Th17 cells in the peripheral blood of children infected with enterovirus 71

Enterovirus 71 (EV71) affects the health of young children globally causing severe neurologic diseases. The relationship between EV71 infection and T helper type 17 (Th17) has not been described, although this new Th subset or interleukin-17 (IL-17) has been reported to be associated with other viral infections. The purpose of the current study was to describe the immune profile involving Th17 cells, neutrophils, and related factors and to speculate on the possible immunopathogenesis of EV71 infections. Flow cytometry and an automatic blood cell counter were used to analyze circulating Th17 cells and count neutrophils, respectively. Expression of acid-related orphan nuclear receptor gamma t (ROR γt) was evaluated by reverse-transcriptional PCR, and enzyme linked immunosorbent assays (ELISAs) were used for detecting concentrations of IL-17, IL-23, and IFN-γ. The results showed that the frequencies of Th17 cells (1.47 ± 0.87%) and the number of neutrophils (7.4 ± 4.1 × 10(9) /L) in peripheral blood samples from children infected with EV71 were significantly higher compared to controls. In addition, there was a statistically higher expression of ROR γt in peripheral blood mononuclear cells (PBMCs) and elevated concentrations of IL-17 and IL-23 in sera, but lower IFN-γ production during EV71 infections. The findings suggest that Th17 cells are mediators during the immunologic process.

Pivotal roles of the interleukin-23/T helper 17 cell axis in hepatitis B

T helper 17 (Th17) cells are a newly identified subset of T helper cells that play important roles in host defense against extracellular bacteria, as well as in the pathogenesis of autoimmune disease. Research interest in these cells was piqued when hepatitis B virus (HBV)-infected patients were found to have significantly elevated Th17 cell frequency, and it was proposed that these proinflammatory effectors may promote the HBV disease process. Subsequent studies have revealed that Th17 cells drive immune-mediated pathology of HBV infection, and that IL-23 amplifies the Th17 cell responses and liver inflammation. As a result, new pathways of HBV-mediated liver damage have been elucidated, along with promising new targets of molecular therapeutic strategies. Ongoing research is also providing significant insights into the target cells and underlying mechanisms of Th17-secreted cytokines, including IL-17A, IL-21 and IL-22. Future studies are expected to fully uncover the cytokine-related mechanisms mediating HBV-induced liver inflammation, and to determine the yet unknown cell source of IL-23. This review will draw upon the most up-to-date available data to discuss the putative roles and detailed mechanisms of IL-23/Th17 cell axis in HBV infection-mediated liver pathogenesis.

Update on the immunological pathway of negative regulation in acute insults and sepsis

Sepsis with subsequent multiple organ dysfunction is a distinctly systemic inflammatory response to concealed or known infection and is a leading cause of death in intensive care units. In the initial stage of sepsis, a phase of immune activation can be evident, but a marked apoptosis-induced depletion of lymphocytes and a nonspecific anergy of immune function after severe trauma and burns might be responsible for the increased susceptibility of the host to subsequent septic complications. Recent studies indicated that negative regulation of immune function plays a pivotal role in the maintenance of peripheral homeostasis and regulation of immune responses; therefore, an understanding of the basic pathways might give rise to novel insights into the mechanisms of sepsis and immune homeostasis. This review is an attempt to provide a summary of the different pathways of negative regulation that are involved in the pathogenesis of sepsis, secondary to acute insults.

Influence of HBV on the interleukin-17 receptor signaling pathway in HepG2 cells

AIM: To investigate whether hepatitis B virus influences the expression of interleukin-17 (IL-17) receptor and the adaptor Act1 in HepG2 cells.

METHODS: The mRNA and protein expression of IL-17 receptor and the adaptor Act1 was determined by real-time PCR and Western blot, respectively. NF-kappa B nuclear translocation was detected by immunofluorescence. The content of IL-17 in cell supernatants was measured by ELISA.

RESULTS: IL-17 was not detected in the culture supernatants of HepG2 cells, and IL-17 mRNA expression was not detected in HepG2 cells. The mRNA and protein expression of IL-17 receptor was significantly lower in HepG2 cells infected with HBV recombinant adenovirus than in cells infected with corresponding concentration of wild adenovirus (mRNA: 0.68±0.02 0.89±0.03, 0.33±0.06 vs 0.81±0.01, 0.12±0.01 vs 0.86±0.05, all P < 0.05; protein: 0.84±0.12 vs 1.01±0.13, 0.56±0.09 vs 1.01±0.08, 0.24±0.08 vs 0.98±0.05, all P < 0.05), and the impact of HBV on the IL-17 receptor expression was dose- and time-dependent. However, HBV had no significant impact on the expression of adaptor Act1. Furthermore, HBV recombinant adenovirus inhibited NF-κB activation induced by IL-17 receptor.

CONCLUSION: Our results indicate that HBV recombinant adenovirus can down-regulate the mRNA and protein expression of IL-17 receptor, inhibit NF-κB activation induced by IL-17R, and thereby prevent the IL-17 receptor signaling pathway in HepG2 cells.

Changes of Treg and Th17 cells balance in the development of acute and chronic hepatitis B virus infection

Background

Many studies suggest that in chronic hepatitis B virus (HBV) infection regulate T (Treg) cells and interlukin-17-producing T help cells (Th17) are mutually antagonistic in the immune response. This study is aimed to reveal the cell differentiation environment and the significance of Treg and Th17 balance in the development of acute and chronic HBV infection.

Methods

Ten patients with acute HBV infection (AHB) and forty-eight patients with chronic HBV infection, including 12 asymptomatic HBV carriers (HBV carriers), 18 chronic hepatitis B patients (CHB) and 18 acute-on-chronic HBV-related liver failure (ACHBLF) were enrolled. Treg and Th17 cells differentiation related cytokine levels were detected by using ELISA. Flow cytometry was employed to count the Treg and Th17 frequency in peripheral blood.

Results

Compared to health controls both AHB and ACHBLF patients favoured Th17 cell differentiation, accompanied by a higher proportion of peripheral Th17 cells (P < 0.01) and high level of interleukin-17A (IL-17A) (P < 0.01). However, asymptomatic HBV carriers and CHB were conducive to Treg cell differentiation. In AHB and ACHBLF, peripheral blood IL-17A + CD4 + T cell frequency increased significantly compared with healthy controls. Changes of Treg and Th17 cell frequency were not completely consistent. Both CHB and ACHBLF had lower level of Treg/Th17 ratio than in health control (P < 0.05). Both plasm IL-17A levels (r = −0.72, p<0.001) and Th17 frequency(r = −0.49, p = 0.0003) negatively correlated with plasma HBV DNA load in patients with chronic HBV infection. In addition, both Th17 frequency and plasm IL-17A levels positively correlated with ALT (r = 0.33,p = 0.01 Vs r = 0.29,p = 0.04) and total bilirubin levels (r = 0.72,p<0.0001 Vs r = 0.53,p = 0.0001) in these chronic HBV-infected subjects. However, for AHB there were positive correlation between both Th17 frequency (r = 0.64, p = 0.04) and plasm IL-17A levels (r = 0.69, p = 0.02) with serum ALT levels, but no significant correlation between both HBV DNA level and total bilirubin level with Th17 frequency or plasm IL-17A levels were found. Furthermore, Treg/Th17 ratio was negatively correlated with total bilirubin levels (r = −0.41, p = 0.004) in chronic HBV-infected patients, especially in patients with ACHBLF (r = −0.69,p = 0.001) and positively correlated with viral load in these chronic HBV-infected subjects (r = 0.55, p<0.0001).

Conclusions

Th17 cells are involved in acute and chronic HBV infection, especially in AHB and ACHBLF. CHB and ACHBLF patients manifested obvious Treg/Th17 ratio imbalance, which might be linked to disease progression and the continuous HBV infection.

Different models in predicting the short-term prognosis of patients with hepatitis B virus-related acute-on-chronic liver failure

BACKGROUND AND AIMS

Effective assessing the prognosis of patients with end-stage liver disease is always challenging. This study aimed to investigate the accuracy of different models in predicting short-term prognosis of patients with hepatitis B virus (HBV)-related acute-on-chronic liver failure (ACLF).

MATERIAL AND METHODS

We retrospectively evaluated survival of a cohort of patients with at least 3-month follow up. The receiver-operating-characteristic curves (ROC) were drawn for Child-Turcotte-Pugh (CTP) classification, King's College Hospital (KCH) criteria, model for end-stage liver disease (MELD), MELD combined with serum sodium (Na) concentration (MELDNa), integrated MELD (iMELD) and logistic regression model (LRM).

RESULTS

Of the 273 eligible patients, 152 patients (55.7%) died within 3-month follow up. In cirrhotic patients (n = 101), the AUCs of LRM (0.851), MELDNa (0.849), iMELD (0.845) and MELD (0.840) were all significantly higher than those of KCH criteria (0.642) and CTP (0.625) (all p < 0.05), while the differences among LRM, MELD, MELDNa and iMELD were not significant, and the most predictive cutoff value was 0.5176 for LRM, 30 for MELDNa, 47.87 for iMELD and 29 for MELD, respectively. In non-cirrhotic patients (n = 172), the AUC of LRM (0.897) was significantly higher than that of MELDNa (0.776), iMELD (0.768), MELD (0.758), KCH criteria (0.647) and CTP (0.629), respectively (all p < 0.05), and the most predictive cutoff value for LRM was -0.3264.

CONCLUSIONS

LRM, MELD, MELDNa and iMELD are with similar accuracy in predicting the shortterm prognosis of HBV-ACLF patients with liver cirrhosis, while LRM is superior to MELD, MELDNa and iMELD in predicting the short-term prognosis of HBV-ACLF patients without liver cirrhosis.

Acute-on-chronic liver failure in chronic hepatitis B

Acute-on-chronic liver failure (ACLF) in chronic hepatitis B (CHB) is most commonly caused by acute severe exacerbation of CHB. The pathophysiology of ACLF in CHB is still poorly understood. Despite the identification of important predisposing factors and prognostic markers, ACLF in CHB remains a disease associated with high mortality. The majority of studies using nucleoside analog therapy did not show any significant improvement in survival, although larger prospective studies are needed. Liver transplantation is the definitive treatment for ACLF in CHB. The challenge ahead would be prognosticating cases with favorable or unfavorable outcomes in order to streamline patients for early transplantation or for medical therapy.

Trace metal imbalance associated with oxidative stress and inflammatory status in anti-hepatitis C virus antibody positive subjects

Toxic and essential trace metals, oxidative stress, and inflammatory status were evaluated in anti-hepatitis C virus (HCV) antibody-positive subjects. Blood biochemical parameters were determined in anti-HCV antibody-positive (n=17) and -negative controls (n=46). Compared with controls, anti-HCV antibody-positive individuals had significantly lower concentrations of plasma zinc (Zn); higher copper (Cu), iron (Fe), lead (Pb), cadmium (Cd), and aluminum (Al); and lower activities of erythrocyte antioxidant enzymes glutathione peroxidase and catalase, and elevated superoxide dismutase. Significantly increased lipid peroxidation malondialdehyde (MDA), and inflammatory markers such as alanine aminotransferase (ALT), high sensitivity C-reactive protein (hs-CRP), ferritin, and Cu/Zn ratios, as well as decreased albumin and high density lipoprotein (HDL) concentrations were observed. We have found significant interactions between toxic (e.g., Pb, Cd, and Al) and essential metals (e.g., Zn, Cu, Fe), which correlated with MDA. In conclusion, anti-HCV antibody-positive subjects had abnormal distributions of trace metals that may aggravate oxidative stress and inflammation, and exacerbate hepatic damage.

Increased frequency of circulating Th17 cells in acute-on-chronic hepatitis B liver failure

BACKGROUND

T helper (Th) 17 cells participate in the pathogenesis of liver diseases but their exact role in acute-on-chronic hepatitis B liver failure (ACHBLF) still remains obscure.

AIMS

This present study was aimed to characterize the circulating Th17 cells and to analyze their association with disease progression in ACHBLF.

METHODS

This retrospective study consisted of 40 ACHBLF patients, 40 chronic hepatitis B (CHB) patients and 20 healthy controls. The frequency of peripheral Th17 cells and IL-17 mRNA level in peripheral blood mononuclear cells (PBMCs) were estimated by flow cytometry and relative quantitative real-time polymerase chain reaction.

RESULTS

We found that the frequency of peripheral Th17 cells, as well as the level of IL-17 mRNA in PBMCs, was significantly increased in ACHBLF patients compared with CHB patients and healthy controls. In ACHBLF patients, the frequency of Th17 cells was positively correlated with serum total bilirubin (r = 0.392, P = 0.012) and model for end-stage liver disease scores (r = 0.383, P = 0.015), but negatively correlated with prothrombin activity (r = -0.317, P = 0.046). The same trend was observed as for relative expression of IL-17. Furthermore, the frequency of Th17 cells and IL-17 mRNA level were significantly elevated in non-survivors compared with survivors in ACHBLF patients.

CONCLUSIONS

These results suggested that Th17 cells as well as IL-17 might be related with disease severity and prognosis in ACHBLF patients.

The anti-inflammatory TIPE2 is an inhibitor of the oncogenic Ras

The connection between cancer and inflammation is widely recognized, yet the underlying molecular mechanisms are poorly understood. We report here that TIPE2 provides a molecular bridge from inflammation to cancer by targeting the Ras signaling pathway. TIPE2 binds the Ras-interacting domain of the RalGDS family of proteins, which are essential effectors of activated Ras. This binding prevented Ras from forming an active complex, thereby inhibiting the activation of the downstream signaling molecules Ral and AKT. Consequently, TIPE2 deficiency led to heightened activation of Ral and AKT, resistance to cell death, increased migration, and dysregulation of exocyst complex formation. Conversely, TIPE2 overexpression induced cell death and significantly inhibited Ras-induced tumorigenesis in mice. Importantly, TIPE2 expression was either completely lost or significantly downregulated in human hepatic cancer. Thus, TIPE2 is an inhibitor of both inflammation and cancer, and a potential drug target for inflammatory and neoplastic diseases.

Th17 cells are increased with severity of liver inflammation in patients with chronic hepatitis C

BACKGROUND AND AIM

As a newly identified subset of T helper cells, T-helper 17 cells (Th17) are major mediators of inflammation-associated disease. Some reports have revealed significantly increased Th17 cells in hepatitis B virus-infected patients, and a recent study has demonstrated that hepatitis C virus (HCV)-specific Th17 cells can be induced in vitro and regulated by transforming growth factor-β. This study attempted to characterize the role of Th17 cells in the disease progression of chronic hepatitis C (CHC).

METHODS

The current study enrolled 53 patients with CHC and 23 healthy controls, in which the circulating and liver-infiltrating Th17 cells were monitored.

RESULTS

We found that CHC patients had increased proportions of both circulating and liver-infiltrating Th17 cells compared to healthy individuals, and both measures of Th17 cells were correlated with severity of liver inflammation. We further demonstrated that the HCV-specific Th17 cells were correlated with liver damage but not HCV viral replication.

CONCLUSIONS

Such a correlation between the severity of liver damage of CHC and Th17 cells illustrated in this study sheds some light on the understanding of the pathogenesis of CHC.

A Novel prognostic scoring system to predict 3-month mortality risk in patients with acute-on-chronic liver failure in hepatitis B: a retrospective cohort study

PURPOSE

The present study was done to establish an objective, sensitive prognostic scoring system and to determine the applicability of this model in predicting the 3-month mortality of patients with acute-on-chronic liver failure in hepatitis B (ACLFB).

METHODS

We developed a novel prognostic scoring system, calculated from six clinical indices including serum total bilirubin, prothrombin activity, serum creatinine, hepatic encephalopathy, infections, and the depth of ascites from 499 patients with ACLFB. Differences in the sensitivity, specificity, and practicality of a Novel prognostic scoring system and the model of end-stage liver disease (MELD) were analyzed.

RESULTS

The areas under the receiver operating characteristic curve (ROC) for the Novel scoring systems and MELD scoring systems were 0.967 (95% CI, 0.956-0.977) and 0.900 (95% CI, 0.878-0.922), respectively. The analysis of the ROC curve indicated that the Novel scoring systems were an exact, pertinent, and objective prognostic model with greater accuracy than the MELD. In the Novel scoring systems, the survival rate of these patients whose scores ranged from 2 to 6 was 98.80%, while for those whose scores point at 7 and 15, the mortality rates were 8.70% (2/23) and 95.45% (21/22), respectively, and the mortality rate of these patients whose scores were 16 and above was 100.00%. However, in the MELD prognostic scoring systems, there were no score ranges with 100.00% survival rate.

CONCLUSIONS

We developed an objective, pertinent, and sensitive prognostic scoring system that predicted the 3-month mortality of patients with ACLFB with greater accuracy than the MELD.

Upregulation of IL-23 expression in patients with chronic hepatitis B is mediated by the HBx/ERK/NF-κB pathway

IL-23 is a newly discovered proinflammatory cytokine that contributes to the maintenance and expansion of Th17 cells. IL-23 has recently been identified as playing a critical role in a number of chronic inflammatory diseases. However, the regulatory mechanism of IL-23 in chronic hepatitis B (CHB) remains largely unknown. The aims of this study were to detect the expression of IL-23 in CHB patients and to explore the molecular mechanism of hepatitis B virus (HBV)-induced IL-23 expression. Serum levels and hepatic expression of IL-23 were significantly upregulated in CHB patients. A positive correlation was found between IL-23 expression and the histological activity index score, HBV DNA load, and serum alanine aminotransferase and aspartate aminotransferase levels. HBx protein increased IL-23 expression in a dose-dependent manner. It also aided in the nuclear translocation of NF-κB, which directly bound to the promoters of IL-23 subunits p19 and p40 to facilitate their transcription. NF-κB inhibitors blocked the effect of HBx on IL-23 induction, and NF-κB subunits p65 and p50 increased the augmented IL-23 expression. Inhibition of ERK1/2 activation and transfection with ERK dominant-negative plasmid significantly blocked the HBx-induced IL-23 expression. Furthermore, PI3K and Ras-MEK-MAPK inhibitors significantly decreased the ERK1/2 activation and IL-23 expression. Thus, we report a new molecular mechanism for HBV-induced IL-23 expression, which involves the activation of the ERK/NF-κB pathway by HBx, leading to the transactivation of the IL-23 p19 and p40 promoters.

IL-17 boosts proinflammatory outcome of antiviral response in human cells

Excessive inflammation during bacterial and viral infections is destructive to the host and involves elevated production of proinflammatory cytokines. It is especially deleterious in organs with space constraints such as lung and the CNS. Indeed, a number of viruses that infect lungs, such as avian influenza virus, SARS-associated coronavirus, and respiratory syncytial virus, elicit a very high level of proinflammatory cytokines; however, it is unclear what triggers their production. In this study, we show that IL-17 commonly produced during viral infection specifically augments a proinflammatory response by directly synergizing with antiviral signaling. Costimulation of primary human fibroblasts with IL-17 greatly enhanced respiratory syncytial virus-induced or synthetic dsRNA-based viral mimic polyinosinic:polycytidylic acid-induced expression of proinflammatory genes without affecting expression of IFN-β-stimulated or IFN-stimulated genes. Knockdown of expression of known mediators of the antiviral signaling pathway revealed that the IL-17-poly(I:C) synergy depends on the presence of the transcriptional factors RelA and IFN regulatory factor 3 and IκB kinases. Moreover, this synergy was blocked by an IκB kinase inhibitor, BAY 11-7082. These findings shed light on the molecular mechanisms behind IL-17-dependent immunopathology observed in viral infections.

FibroTest and Fibroscan performances revisited in patients with chronic hepatitis C. Impact of the spectrum effect and the applicability rate

BACKGROUND

Two widely used biomarkers of fibrosis, FibroTest and liver stiffness measurement (LSM), have been mostly validated in patients with chronic hepatitis C (CHC) using the standard area under the ROC curve (sAUROC) which is not the most appropriate method due to the risk of fibrosis spectrum effect. Furthermore the performance of these biomarkers have not been assessed in "intention to diagnose" which takes into account the failures and non-reliable results.

AIM

The aim was to compare the accuracy of FibroTest and LSM for the diagnosis of fibrosis using sAUROC, the pairwise comparison of fibrosis stages by Obuchowski measure (wAUROC), and these AUROCs reassessed after taking into account the applicability rates.

METHODS

One thousand two hundred and eighty-nine patients with CHC and 604 healthy volunteers were analyzed. The performances of biomarkers assessed were compared in a patients-only group (P1: n=1289), in a population combining both patients and healthy volunteers (P2: n=1893) and in a simulated population (P3: n=1893) with the prevalence of stages observed in a reference population, to demonstrate the impact of spectrum effect. Applicability rates were estimated prospectively in 24,872 consecutive FibroTest and in 13,669 consecutive LSM examinations.

RESULTS

Using wAUROC, the conclusions of studies with reliable results in P1 were different than in those of P2 and in P3. There was a lower performance of FibroTest versus LSM in P1 (0.864 [0.855-0.873] vs. 0.883 [0.874-0.892]; P=0.002) which was not found in P2 (0.893 [0.887-0.900] vs. 0.894 [0.887-0.901]; P=0.86) and in P3 (0.899 [0.893-0.905] vs 0.902 [0.895-0.909]; P=0.60). Using the sAUROC, in P1, P2 and P3, there was no significant difference between FibroTest and LSM performance for advanced fibrosis and a lower performance of FibroTest versus LSM for cirrhosis. In intention to diagnose, using wAUROCs performances were higher for FibroTest vs. LSM in P1 (0.857 [0.848-0.866] vs. 0.814 [0.807-0.821]; P<0.0001) and P2 (0.885 [0.879-0.892] vs. 0.743 [0.737-0.749]; P<0.0001), without difference in P3 (0.891 [0.885-0.897] vs. 0.894 [0.887-0.901]; P=0.90). Using sAUROC, the significant differences in favor of FibroTest vs LSM persisted also for the diagnosis of advanced fibrosis, both in P1 and P2 (P<0.0001) and for the diagnosis of cirrhosis in P1 (P<0.001).

CONCLUSION

When the spectrum effects and applicability rates were taken into account, LSM had lower performance results than FibroTest for the diagnosis of fibrosis stages.

Hepatitis B virus impairs TLR9 expression and function in plasmacytoid dendritic cells

Plasmacytoid dendritic cells (pDCs) play a key role in detecting pathogens by producing large amounts of type I interferon (IFN) by sensing the presence of viral infections through the Toll-Like Receptor (TLR) pathway. TLR9 is a sensor of viral and bacterial DNA motifs and activates the IRF7 transcription factor which leads to type I IFN secretion by pDCs. However, during chronic hepatitis B virus (HBV) infection, pDCs display an impaired ability to secrete IFN-α following ex vivo stimulation with TLR9 ligands. Here we highlight several strategies used by HBV to block IFN-α production through a specific impairment of the TLR9 signaling. Our results show that HBV particle internalisation could inhibit TLR9- but not TLR7-mediated secretion of IFN-α by pDCs. We observed that HBV down-regulated TLR9 transcriptional activity in pDCs and B cells in which TLR9 mRNA and protein levels were reduced. HBV can interfere with TLR9 activity by blocking the MyD88-IRAK4 axis and Sendai virus targeting IRF7 to block IFN-α production. Neutralising CpG motif sequences were identified within HBV DNA genome of genotypes A to H which displayed a suppressive effect on TLR9-immune activation. Moreover, TLR9 mRNA and protein were downregulated in PBMCs from patients with HBV-associated chronic hepatitis and hepatocellular carcinoma. Thus HBV has developed several escape mechanisms to avoid TLR9 activation in both pDCs and B lymphocytes, which may in turn contribute to the establishment and/or persistence of chronic infection.

The tug-of-war between dendritic cells and human chronic viruses

The human immune system is under constant challenge from many viruses, some of which the body is successfully able to clear. Other viruses have evolved to escape the host immune responses and thus persist, leading to the development of chronic diseases. Dendritic cells are professional antigen-presenting cells that play a major role in both innate and adaptive immunity against different pathogens. This review focuses on the interaction of different chronic viruses with dendritic cells and the viruses' ability to exploit this critical cell type to their advantage so as to establish persistence within the host.

Expression of human glucocorticoid receptor in T lymphocytes in acute-on-chronic hepatitis B liver failure

BACKGROUND

Glucocorticoid receptor (GR) participates in the pathogenesis of liver inflammation. However, the potential role of GR in acute-on-chronic hepatitis B liver failure (ACHBLF) is still obscure.

AIM

This present study was aimed to determine peripheral GR expression in ACHBLF patients.

METHODS

Forty patients with ACHBLF, 20 patients with chronic hepatitis B (CHB) and 16 healthy controls were included in this retrospectively study. Flow cytometry was used to determine the peripheral expression of GR + T lymphocytes. Semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) was performed for assessing relative mRNA levels of GR alpha and beta isoforms in peripheral blood mononuclear cells. Serum cortisol level was evaluated using radioimmunoassay.

RESULTS

The serum cortisol level and the percentage of GR + T lymphocytes in ACHBLF patients were significantly decreased compared with CHB patients and healthy controls. However, there were no significant differences in mean fluorescence intensity (MFI) of GR + T lymphocytes within three groups. The relative GR alpha mRNA expression in ACHBLF patients was significant decreased compared with healthy controls. However, the relative GR beta mRNA expression in ACHBLF patients was significantly increased compared with CHB patients and healthy controls. In ACHBLF patients, the percentage of GR + T lymphocyte was significantly positively associated with relative GR alpha expression, prothrombin activity, and HBV DNA level, but negatively correlated with serum cortisol level and MELD score. Furthermore, the percentage of GR + T lymphocytes was also obviously elevated in survivors than non-survivors.

CONCLUSIONS

It was strongly suggested that GR play an important role in the pathogenesis of ACHBLF.

The ratio of Th-17 to Treg cells is associated with survival of patients with acute-on-chronic hepatitis B liver failure

Both T-helper 17 cells (Th-17) and CD4(+)CD25(+) regulatory T cells (Tregs) play important roles in the pathogenesis of hepatitis B virus (HBV) infection. Recent studies have suggested that Th-17 and Treg cells are increased in patients with chronic hepatitis B (CHB). This study further characterizes Th-17 and Treg cells in the blood of HBV-associated acute-on-chronic liver failure (ACLF) patients, and aids our understanding of how the two subsets of CD4(+) T cells affect each other and contribute to survival. Blood samples were obtained from 30 patients with HBV-associated ACLF, 30 patients with CHB, and 30 normal controls (NC). The frequencies of Th-17 and Treg cells were determined by intracellular cytokine staining analysis. To observe the suppressive function of Tregs, purified CD4(+)CD25(+) Tregs from peripheral blood mononuclear cells (PBMCs) were co-cultured with CD4(+)CD25(-) T cells for 48 h, and then IFN-γ and IL-17A from the supernatants were measured by ELISA. We found that both Th-17 and FoxP3(+) Treg cells were increased in ACLF patients. IL-17A secretion by CD4(+) T cells was not regulated by Treg cells, even though Tregs exhibited significant inhibition of IFN-γ production. Most importantly, the ratio of Th-17 to Treg cells was associated inversely with the survival of ACLF patients. These findings provide new information regarding the pathogenesis of HBV-associated ACLF, and the ratio of Th-17 to Tregs may represent a potential prognostic marker for the disease.

Elevated IL-6 receptor expression on CD4+ T cells contributes to the increased Th17 responses in patients with chronic hepatitis B

Background

Increased numbers of Interleukin-17-producing CD4⁺ T cells (Th17) have been found in association with hepatitis B virus (HBV)-induced liver injury. However, the mechanism underlying the increase of Th17 responses in patients with HBV infection remains unclear. In this study, we investigate the possible regulatory mechanisms of increased Th17 responses in patients with chronic hepatitis B(CHB).

Methods

Th17 response and IL-6R expression on CD4⁺ T cells in peripheral blood samples were determined by flow cytometry. Cytokines TGF-β, IL-1β, IL-6 and IL-17 in plasma and/or supernatant samples were determined by ELISA and the IL-17 and IL-6R mRNA levels were quantified by quantitative real-time reverse polymerase chain reaction.

Results

All these data indicated that the frequency of periphery Th17 cells is significantly correlated with the percentage of CD4⁺ T cells expressing IL-6R in CHB patients. CD4⁺ T cells from patients with CHB, but not those from healthy donors, produced higher levels of IL-17 and had more IL-6R expression upon stimulation with the HBV core antigen (HBcAg) in vitro. The PMA/ionomycin and HBcAg -stimulated up-regulation of IL-17 production by CD4⁺ T cells could be reversed by a neutralizing antibody against IL-6R.

Conclusion

we showed that enhancement of IL-6R expression on CD4⁺ T cells upon HBV infection contributes to increased Th17 response in patients with CHB.

Enhanced demethylation of interferon-γ gene promoter in peripheral blood mononuclear cells is associated with acute-on-chronic hepatitis B liver failure

Acute-on-chronic hepatitis B liver failure (ACHBLF) refers to liver failure occurring in patients with chronic hepatitis B (CHB) related liver diseases. Interferon-γ (IFN-γ) plays an important role in the exacerbation of liver function. However, the exact mechanism, by which IFN-γ mediates ACHBLF, is not fully understood. Forty patients with ACHBLF, fifteen patients with CHB and ten healthy controls were included in this present study. ELISA was performed to measure the level of serum IFN-γ. The methylation status of IFN-γ promoter in peripheral blood mononuclear cells (PBMCs) was determined using methylation-specific PCR. Model for End-stage Liver Disease (MELD) scoring was performed for evaluating the severity of liver failure. The serum level of IFN-γ in patients with ACHBLF or CHB was significantly lower than that in healthy controls, while the serum IFN-γ level in ACHBLF patients was significantly higher than that in CHB patients. In ACHBLF patients, the level of IFN-γ was positively correlated with total bilirubin and MELD score, but negatively correlated with prothrombin time activity. These results suggest the involvement of IFN-γ in the pathogenesis of ACHBLF. Importantly, the degree of methylation of the IFN-γ gene promoter in ACHBLF patients (60%, 24/40) was significantly lower than that in CHB patients (93%, 14/15), but was higher than that in the control group (20%, 2/10). Furthermore, in ACHBLF patients, the serum IFN-γ level was significantly higher in unmethylation group than that in methylation group. In conclusion, enhanced demethylation of IFN-γ gene promoter in PBMCs may be associated with the onset of ACHBLF.

Activated IL-23/IL-17 pathway closely correlates with increased Foxp3 expression in livers of chronic hepatitis B patients

Background

Foxp3 protein plays a critical role in mediating the inflammatory response and can inhibit the proinflammatory IL-23/IL-17 pathway. However, the molecular interplay of Foxp3 and the IL-23/IL-17 pathway in patients with chronic hepatitis B (CHB) remains unclear. To this end, we analyzed the expression patterns of Foxp3- and IL-23/IL-17 pathway-related proinflammatory cytokines in 39 patients with acute-on-chronic liver failure, 71 patients with CHB and 32 healthy controls.

Results

Foxp3 expression was found to be elevated in and mainly expressed by the CD4⁺ T cell sub-population of peripheral blood mononuclear cells and liver tissues of patients with hepatitis B. The intrahepatic expression of Foxp3 strongly correlated with the copies of HBV DNA and the concentration of surface antigen, HBsAg. IL-23/IL-17 pathway-related proinflammatory cytokines were also found to be significantly increased in patients' liver tissues, as compared to healthy controls. Moreover, Foxp3 expression was strikingly correlated with the production of these cytokines in liver tissues of CHB patients.

Conclusions

The closely-correlated increase of Foxp3 and IL-23/IL-17 pathway activity in HBV-infected livers suggests that the proinflammatory IL-23/IL-17 pathway had not been effectively suppressed by the host immune machinery, such as Treg (Foxp3) cells. Constitutive activation of the IL-23/17 pathway, thus, may support the chronic hepatitis B state.

Recent advances in the research of hepatitis B virus-related hepatocellular carcinoma: epidemiologic and molecular biological aspects

Hepatocellular carcinoma (HCC) is one of the commonest cancers worldwide, and more than half of HCC patients are attributable to persistent hepatitis B virus (HBV) infections. The best and cheapest way to prevent HBV-related HCC is the implementation of universal hepatitis B vaccination program, by which the incidence rates of childhood HCC have been reduced in several countries, including Taiwan. However, there are still hundreds of millions of HBV carriers in the world that remain a global health challenge. In the past decade, several hepatitis B viral factors such as serum HBV DNA level, genotype, and naturally occurring mutants have already been identified to influence liver disease progression and HCC development in HBV carriers. Several easy-to-use scoring systems based on clinical and viral characteristics are developed to predict HCC risk in HBV carriers and may facilitate the communication between practicing physicians and patients in clinical practice. In addition, the role of nonviral factors in HBV-related HCC has also been increasingly recognized. On the basis of these emerging data, it is recommended that HBV carriers should be screened and monitored to identify those who have a higher risk of liver disease progression and require antiviral treatments. Regarding the molecular carcinogenesis of HCC development, despite some progress in the research of cell biology of HCC in the past decade, aberrant pathways involved in maintaining HCC phenotypes have not been completely elucidated yet. In the future, through comprehensive and integrated approaches to analyze the genomes of human HCC, novel target genes or pathways critically involved in hepatocarcinogenesis may hopefully be identified.

Roles of circulating soluble interleukin (IL)-6 receptor and IL-6 receptor expression on CD4+ T cells in patients with chronic hepatitis B

OBJECTIVES

The objective of this study was to investigate the potential clinical roles of circulating soluble interleukin (IL)-6 receptor (sIL-6R) and IL-6R expression on CD4+ T cells (CD4+ IL-6R+ T cells) in chronic hepatitis B (CHB) patients.

METHODS

One hundred and thirty-three subjects, including 72 CHB patients, 27 asymptomatic carriers, eight acute hepatitis B (AHB) patients, and 26 healthy donors were included in this study. Plasma IL-6 and sIL-6R levels were measured by enzyme-linked immunosorbent assay (ELISA); the frequency of CD4+ IL-6R+ T cells was detected by flow cytometry analysis.

RESULTS

Our data showed a significant increase in plasma sIL-6R levels and the frequency of CD4+ IL-6R+ T cells in peripheral blood in CHB patients compared to asymptomatic carriers and healthy controls (both p<0.05). The elevated prevalence of CD4+ IL-6R+ T cells was positively associated with increased serum alanine aminotransferase levels in CHB patients (r = 0.316, p = 0.007), but was not correlated with serum hepatitis B virus (HBV) DNA load. Moreover, CHB patients with an HBV DNA load >1.0 × 10(6) copies/ml had a lower level of plasma sIL-6R than those with an HBV DNA load <1.0 × 10(6) copies/ml.

CONCLUSIONS

Circulating sIL-6R and CD4+ IL-6R+ T cells were increased in CHB patients. Elevated plasma sIL-6R is probably associated with HBV elimination, and CD4+ IL-6R+ T cells in peripheral blood might contribute to the pathogenesis of liver injury in CHB patients.

T helper type 1/T helper type 17-related cytokines in chronic hepatitis C patients before and after interferon and ribavirin therapy

OBJECTIVE

This study examined the T helper (Th) 1/Th17-related cytokines, interferon (IFN)-γ and interleukin (IL)-17 in the serum of biopsy-proven chronic hepatitis C patients before and after IFN and ribavirin therapy to address whether or not viral clearance is related to Th1/Th17 cytokines.

SUBJECTS AND METHODS

The serum levels of IFN-γ and IL-17 were assayed by ELISA on 26 patients with chronic hepatitic C virus (HCV) infection before the start and 3 months after treatment with pegylated IFN-α plus ribavirin and compared with sera from 15 normal control subjects.

RESULTS

IFN-γ and IL-17 levels are higher in the serum of patients with chronic hepatitis than in normal controls and these elevated levels were not directly correlated (r = -0.01, p = 0.96 for IFN-γ and r = -0.08, p = 0.66 for IL-17) to the viremic state of the HCV infection. In contrast to IL-17, IFN-γ showed significant reduction after 12 weeks of treatment with pegylated IFN plus ribavirin. However, IFN-γ and IL-17 serum levels were not significantly (p = 0.19 and = 0.70, respectively) different among responders and nonresponders for pegylated IFN plus ribavirin therapy.

CONCLUSION

Our findings suggest that the combined treatment with pegylated IFN-α and ribavirin downmodulates the secretion of key cytokine IFN-γ as early as 12 weeks after treatment in infected patients. These findings could encourage new exciting possibilities for immune-based interventions with the aim of restoring functional antiviral T cell responses combined with improved viral clearance.

T-helper 17 cell: A distinctive cell in liver diseases

T-helper (Th)17 cells, a new population of effector CD4(+) T cells, are characterized by the secretion of interleukin (IL)-17. It has been demonstrated that Th17 cells are distinct from Th1 and Th2 cells; they play important roles in the pathogenesis of numerous inflammatory and autoimmune diseases; and are closely related to host defense, tumorigenesis and transplant rejection. Moreover, it has been found that these cells have a close and intricate connection with the regulatory T cells, which play an important role in maintaining self-tolerance and down-tuning immune responses. In the present review, we find that they are significantly elevated in various kinds of liver diseases including liver autoimmunity and inflammatory diseases, alcoholic liver disease and hepatocellular carcinoma.

Simultaneous genotyping and quantification of hepatitis B virus for genotypes B and C by real-time PCR assay

Hepatitis B virus (HBV) is an important cause of human chronic liver diseases and is a major public health problem. Viral load and HBV genotype play critical roles in determining clinical outcomes and response to antiviral treatment in hepatitis B patients. Viral genotype detection and quantification assays are currently in use with different levels of effectiveness. In this study, the performance of a real-time genotyping and quantitative PCR (GQ-PCR)-based assay was evaluated. Through the use of genotype-specific primers and probes, this assay provides simultaneous identification and quantification of genotypes B and C in a single reaction. Our GQ-PCR correctly identified all predefined genotypes B and C, and no cross-reaction between genotypes B and C were observed. The GQ-PCR identified more cases of HBV infections with mixed genotypes B and C than direct sequencing did. Samples from 127 HBV-infected Chinese patients were genotyped with GQ-PCR, revealing 56.7% HBV as genotype B, 13.4% as genotype C, and 29.8% as mixed genotypes B and C. This assay provides a reliable, efficient, and cost-effective means for quantification of the B and C genotypes of HBV in single or mixed infections. This assay is suitable for sequential monitoring of viral load levels and for determining the relationship between the genotype viral load and stage of disease in Asians.

Therapeutic vaccination in chronic hepatitis B: preclinical studies in the woodchuck

Recommended treatment of chronic hepatitis B with interferon-α and/or nucleos(t)ide analogues does not lead to a satisfactory result. Induction of HBV-specific T cells by therapeutic vaccination or immunotherapies may be an innovative strategy to overcome virus persistence. Vaccination with commercially available HBV vaccines in patients did not result in effective control of HBV infection, suggesting that new formulations of therapeutic vaccines are needed. The woodchuck (Marmota monax) is a useful preclinical model for developing the new therapeutic approaches in chronic hepadnaviral infections. Several innovative approaches combining antiviral treatments with nucleos(t)ide analogues, DNA vaccines, and protein vaccines were tested in the woodchuck model. In this paper we summarize the available data concerning therapeutic immunization and gene therapy using recombinant viral vectors approaches in woodchucks, which show encouraging results. In addition, we present potential innovations in immunomodulatory strategies to be evaluated in this animal model.

Subcellular proteome analysis unraveled annexin A2 related to immune liver fibrosis

It is important to study the mechanism of liver fibrogenesis, and find new non-invasive biomarkers. In this study, we used subcellular proteomic technology to study the plasma membrane (PM) proteins related to immune liver fibrosis and search for new non-invasive biomarkers. A rat liver fibrosis model was induced by pig serum injection. The liver fibrogenesis from stage (S) S0-1, S2, S3-4, and S4 was detected by Masson staining and HE staining in this rat model after 2, 4, 6, and 8 weeks of treatment. The liver PM was enriched and analyzed using subcellular proteomic technology. The differentially expressed proteins were verified by Western blotting, immunohistochemistry, and ELISA. PM with 149-fold purification was obtained and 22 differentially expressed proteins were identified. Of which, annexin A2 (ANXA2) was detected to be increased obviously in S4 compared with S0-1, and verified by Western blotting of rat liver tissue and immunohistochemistry of rat and human liver tissue. The expression of ANXA2 in human plasma with S1-2 was also found to be up-regulated for 1.4-fold than that in S0. Furthermore, ANXA2 was detected to translocate from nuclear membrane and cytosol to PM as HBV stimulation through immunocytochemical analysis in vitro. This study identified 22 differentially expressed proteins related to liver fibrosis, and verified a potential biomarker (ANXA2) for non-invasive diagnosis of immune liver fibrosis. To our knowledge, it was the first time to dynamically study the proteins related to liver fibrosis and select biomarkers for liver fibrosis diagnosis through PM proteome research.

Th17 cells and their associated cytokines in liver diseases

T helper 17 (Th17) cells are a newly identified subset of T helper cells that play important roles in host defense against extracellular bacteria as well as in the pathogenesis of autoimmune disease. The functions of Th17 cells are mediated via the production of several cytokines including interleukin (IL)-17 and IL-22. Recent studies show that the frequency of IL-17(+) cells is significantly elevated in a variety of chronic liver diseases including alcoholic liver disease, viral hepatitis and hepatocellular carcinoma. IL-17 receptor is expressed virtually on all types of liver cells, while IL-22 receptor expression is restricted to epithelial cells including hepatocytes in the liver. IL-17 seems to play an important role in inducing liver inflammation via stimulating multiple types of liver nonparenchymal cells to produce proinflammatory cytokines and chemokines, while IL-22 appears to be an important factor in promoting hepatocyte survival and proliferation.

HBcAg induces interleukin-10 production, inhibiting HBcAg-specific Th17 responses in chronic hepatitis B patients

T-helper (Th) 17 cells have been shown to have an important role in host defense against viral infection. However, little is known about the regulation of Th17 cells in hepatitis B virus (HBV) infections. Peripheral blood mononuclear cells (PBMCs) isolated from patients with chronic hepatitis B (CHB) were stimulated with anti-interleukin (IL)-10 antibody or recombinant IL-10. The frequency of hepatitis B core antigen (HBcAg)-specific Th17 cells was characterized and produced cytokines were determined by flow cytometry. A low frequency of Th17 cells and a high frequency of Th1 cells were detected in CHB patients. HBcAg stimulation promoted IL-17A, IL-22, IL-23, IL-6, transforming growth factor (TGF)-β and IL-10 production by PBMCs from CHB patients, but not from healthy controls. Furthermore, endogenous IL-10 inhibited HBcAg-stimulated production of IL-17A, IL-22, IL-6 and IL-23, but not TGF-β. Treatment with IL-10 inhibited the HBcAg-stimulated activation of Th17 cells, whereas anti-IL-10 antibody significantly increased the frequency of Th17 and Th1 cells, but not that of CD4(+)CD25(+) regulatory T cells, associated with upregulating RORγt expression in CD4(+) T cells. HBcAg stimulated the production of IL-10, which negatively regulated HBcAg-specific Th17 cell responses in CHB patients. Our findings may represent one evasion strategy for HBV to subvert specific antiviral responses in humans.