Lipeng Qiu

Loss of microRNA 122 expression in patients with hepatitis B enhances hepatitis B virus replication through cyclin G1-modulated P53 activity†‡

Hepatitis B virus (HBV) causes chronic infection in about 350 million people worldwide. Given the important role of the most abundant liver‐specific microRNA, miR‐122, in hepatic function and liver pathology, here we investigated the potential role and mechanism of miR‐122 in regulating HBV replication. We found that miR‐122 expression in liver was significantly down‐regulated in patients with HBV infection compared with healthy controls, and the miR‐122 levels were negatively correlated with intrahepatic viral load and hepatic necroinflammation. The depletion of endogenous miR‐122 by its antisense inhibitor led to enhanced HBV replication, whereas overexpression of miR‐122 by transfection of mimic or its expression vector inhibited viral production. We next identified cyclin G1 as an miR‐122 target from multiple candidate target genes that are involved in the regulation of HBV replication. Overexpression and knockdown studies both showed that cyclin G1 regulated viral replication in HBV transfected cells. We also observed that cyclin G1 expression was up‐regulated in HBV‐infected patients, and cyclin G1 levels were inversely associated with miR‐122 expression in liver tissues. Using coimmunoprecipitation, a luciferase reporter system, and electrophoretic mobility shift assay, we further demonstrated that cyclin G1 specifically interacted with p53, and this interaction blocked the specific binding of p53 to HBV enhancer elements and simultaneously abrogated p53‐mediated inhibition of HBV transcription. Finally, we show that miR‐122 suppressed HBV replication in p53 wildtype cells but not in null isogenic cells. Conclusion: miR‐122 down‐regulates its target cyclin G1, and thus interrupts the interaction between cyclin G1 and p53 and abrogates p53‐mediated inhibition of HBV replication. Our work shows that miR‐122 down‐regulation induced by HBV infection can impact HBV replication and possibly contribute to viral persistence and carcinogenesis. (HEPATOLOGY 2012;)

miR-122-induced down-regulation of HO-1 negatively affects miR-122-mediated suppression of HBV

As the most abundant liver-specific microRNA (miRNA), miR-122 has been extensively studied for its role in the regulation of lipid metabolism, hepatocarcinogenesis and hepatitis C virus (HCV) replication, but little is known regarding its role in the replication of Hepatitis B virus (HBV), a highly prevalent hepatotropic virus that can cause life-threatening complications. In this study we examined the effects of antisense inhibition of miR-122 and transfection of a miR-122 mimic on HBV expression in hepatoma cells. The over-expression of miR-122 inhibited HBV expression, whereas the depletion of endogenous miR-122 resulted in increased production of HBV in transfected cells. We further found that the down-regulation of Heme oxygenase-1 (HO-1) by miR-122 plays a negative role in the miR-122-mediated inhibition of viral expression. Our study demonstrates the anti-HBV activity of miR-122, suggesting that therapies that increase miR-122 and HO-1 may be an effective strategy to limit HBV replication.

Treg suppress CTL responses upon immunization with HSP gp96

HSP gp96‐based vaccines have been trialled in rodent models and, more recently, in humans. Better understanding of gp96s immunomodulatory role will help with the design of more effective strategies for treatment of cancer and infectious diseases. In this study, we monitored the activities of T cells and activation of Treg in BABL/c mice after immunization using different doses of gp96 as adjuvant. We found that co‐injection of gp96 simultaneously stimulated both CTL and Treg activity. Activation of CTL at low dose was far more pronounced than Treg activation. Treg population and suppression increased with gp96 dose, eventually abrogating the T‐cell response induced by immunization. Low‐dose cyclophosphamide treatment could restore the T‐cell responses lost after high‐dose gp96 adjuvant injection by suppression of Treg activation. We further examined the effect of different doses of gp96 or N355 peptide administration on tumor rejection. Our results provide new insights into the mechanisms of gp96‐mediated balance between regulatory and responder T cells, which may facilitate future development of an effective gp96‐based therapeutic vaccine.

Heat shock protein gp96 enhances humoral and T cell responses, decreases Treg frequency and potentiates the anti-HBV activity in BALB/c and transgenic mice

More than 350 million people worldwide are chronically infected with hepatitis B virus (HBV). Broad repertoire and strong magnitude of HBV-specific T cell responses are thought to play key roles for virus control and clearance. Previous studies together with ours showed that heat shock protein gp96 as adjuvant induces antigen specific T cell responses, yet little is known for its anti-viral properties. Here, we investigated the role of gp96 mediated cellular and humoral immunity in antiviral effects in HBV transgenic mice. Immunization with HBV surface (HBsAg) and core (HBcAg) antigens combined formulation along with gp96 induced robust antiviral T-cell and antibody immunity against HBsAg and HBcAg. Compared with non-immunized control, immunization with gp96 adjuvant vaccine led to decrease of serum HBs level and HBc expression in hepatocyte by 45% and 90% at maximum, respectively, and decreased serum HBV-DNA level to below or close to the detection limit 4 weeks after the last immunization, suggesting the therapeutic effect. A significant enhancement in cellular responses towards HBcAg and increased infiltration of CD8+ T cells in liver of transgenic were observed under treatment with gp96 compared with no treatment (P<0.05 or 0.01). Treatment with gp96 was capable of reducing Tregs by overall 30-40%. The superior immune responses induced with the aid of gp96 correlated with improved antiviral effect by vaccination with HBsAg and HBcAg. We conclude that gp96 may contribute to enhanced antiviral immunity in transgenic mice at least partly by Treg down-regulation. HBcAg may act as potent adjuvant for Th1 response. Our study reveals the novel property of gp96 in immune modulation and its potential use for breaking immunotolerance in immunotherapy of chronic HBV infection.

Anti-HBV agents derived from botanical origin.

There are 350,000 hepatitis B virus (HBV) carriers all over the world. Chronic HBV infection is at a high risk of developing liver cirrhosis and hepatocelluar carcinoma (HCC), and heavily threatened peoples health. Two kinds of drugs approved by FDA for anti-HBV therapy are immunomodulators (interferon α, pegylated-interferon α) and nucleos(t)ide analogues (lamivudine, adefovir dipivoxil, entecavir, telbivudine, and tenofovir disoproxil fumarate). These drugs have been proved to be far from being satisfactory due to their low specificity, side effects, and high rate of drug resistance. There is an urgent need to discover and develop novel effective anti-HBV drugs. With vast resources, various structures, diverse biological activities and action mechanisms, as well as abundant clinical experiences, botanical agents become a promising source of finding new anti-HBV drugs. This review summarizes the recent research and development of anti-HBV agents derived from botanical origin on their sources and active components, inhibitory effects and possible toxicities, as well as action targets and mechanisms, and also addresses the advantages and the existing shortcomings in the development of botanical inhibitors. This information may not only broaden the knowledge of anti-HBV therapy, and offer possible alternative or substitutive drugs for CHB patients, but also provides considerable information for developing new safe and effective anti-HBV drugs.

Long non-coding RNAs as biomarkers and therapeutic targets: Recent insights into hepatocellular carcinoma

ABSTRACT Hepatocellular carcinoma (HCC) is the most prevalent primary liver cancer worldwide, and the survival rates of patients with HCC remains quite low after 5 years. Long non‐coding RNAs (LncRNAs) are a novel class of non‐coding RNAs that are capable of regulating gene expression at various levels. Recent works have demonstrated that lncRNAs are often dysregulated in HCC, and the dysregulation of some of these lncRNAs are associated with the clinicopathological features of HCC. They regulate cell proliferation, apoptosis, autophagy, Epithelial‐Mesenchymal Transition (EMT), invasion and metastasis of HCC by modulating gene expression and cancer‐related signaling pathways, and thus contribute to the onset and progression of HCC. In this review, we provide a comprehensive survey of dysregulated lncRNAs in HCC, with particular focus on the functions and regulatory mechanisms of several essential and important lncRNAs, and discuss their potential clinical application as early diagnostic and/or prognostic biomarkers or therapeutic targets for HCC. Graphical abstract Figure. No Caption available.

Aryl Hydrocarbon Receptor Protects Lungs from Cockroach Allergen–Induced Inflammation by Modulating Mesenchymal Stem Cells

Exposure to cockroach allergen leads to allergic sensitization and increased risk of developing asthma. Aryl hydrocarbon receptor (AhR), a receptor for many common environmental contaminants, can sense not only environmental pollutants but also microbial insults. Mesenchymal stem cells (MSCs) are multipotent progenitor cells with the capacity to modulate immune responses. In this study, we investigated whether AhR can sense cockroach allergens and modulate allergen-induced lung inflammation through MSCs. We found that cockroach allergen–treated AhR-deficient (AhR−/−) mice showed exacerbation of lung inflammation when compared with wild-type (WT) mice. In contrast, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), an AhR agonist, significantly suppressed allergen-induced mouse lung inflammation. MSCs were significantly reduced in cockroach allergen–challenged AhR−/− mice as compared with WT mice, but increased in cockroach allergen–challenged WT mice when treated with TCDD. Moreover, MSCs express AhR, and AhR signaling can be activated by cockroach allergen with increased expression of its downstream genes cyp1a1 and cyp1b1. Furthermore, we tracked the migration of i.v.-injected GFP+ MSCs and found that cockroach allergen–challenged AhR−/− mice displayed less migration of MSCs to the lungs compared with WT. The AhR-mediated MSC migration was further verified by an in vitro Transwell migration assay. Epithelial conditioned medium prepared from cockroach extract–challenged epithelial cells significantly induced MSC migration, which was further enhanced by TCDD. The administration of MSCs significantly attenuated cockroach allergen–induced inflammation, which was abolished by TGF-β1–neutralizing Ab. These results suggest that AhR plays an important role in protecting lungs from allergen-induced inflammation by modulating MSC recruitment and their immune-suppressive activity.

Antihepatitis B therapy: a review of current medications and novel small molecule inhibitors

There are approximately 350 million hepatitis B virus (HBV) carriers worldwide. Chronic HBV infection increases the risk of liver cirrhosis and hepatocellular carcinoma. To date, two classes of antiviral drugs have been approved by the Food and Drug Administration for the treatment of hepatitis B, immunomodulators (interferon [IFN]‐α and pegylated‐interferon [PEG‐IFN]‐α) and nucleos(t)ide analogs (lamivudine, telbivudine, adefovir, tenofovir [TDF], and entecavir [ETV]). Of these, ETV, TDF, and PEG‐IFN‐α are the most effective and are currently recommended for anti‐HBV therapy. However, these therapies are less than optimal because of their low rate of viral DNA and surface antigen clearance; thus, there exists a significant unmet medical need for safe and efficacious new anti‐HBV drugs. Covering diverse chemical structures and mechanisms of action, non‐nucleos(t)ide compounds offer great promise in the search for new anti‐HBV drugs. This review summarizes the currently approved anti‐HBV drugs and highlights advances in the identification and characterization of novel small molecule HBV inhibitors. We discuss the sources, structures, anti‐HBV effects, mechanisms of action, and potential toxicities of these novel inhibitors.

Mannose receptor modulates macrophage polarization and allergic inflammation through miR-511-3p

&NA; Figure. No caption available. Background: Mannose receptor (MRC1/CD206) has been suggested to mediate allergic sensitization and asthma to multiple glycoallergens, including cockroach allergens. Objective: We sought to determine the existence of a protective mechanism through which MRC1 limits allergic inflammation through its intronic miR‐511‐3p. Methods: We examined MRC1‐mediated cockroach allergen uptake by lung macrophages and lung inflammation using C57BL/6 wild‐type (WT) and Mrc1−/− mice. The role of miR‐511‐3p in macrophage polarization and cockroach allergen–induced lung inflammation in mice transfected with adeno‐associated virus (AAV)–miR‐511‐3p (AAV–cytomegalovirus–miR‐511‐3p–enhanced green fluorescent protein) was analyzed. Gene profiling of macrophages with or without miR‐511‐3p overexpression was also performed. Results: Mrc1−/− lung macrophages showed a significant reduction in cockroach allergen uptake compared with WT mice, and Mrc1−/− mice had an exacerbated lung inflammation with increased levels of cockroach allergen–specific IgE and TH2/TH17 cytokines in a cockroach allergen–induced mouse model compared with WT mice. Macrophages from Mrc1−/− mice showed significantly reduced levels of miR‐511‐3 and an M1 phenotype, whereas overexpression of miR‐511‐3p rendered macrophages to exhibit a M2 phenotype. Furthermore, mice transfected with AAV–miR‐511‐3p showed a significant reduction in cockroach allergen–induced inflammation. Profiling of macrophages with or without miR‐511‐3p overexpression identified 729 differentially expressed genes, wherein expression of prostaglandin D2 synthase (Ptgds) and its product PGD2 were significantly downregulated by miR‐511‐3p. Ptgds showed a robust binding to miR‐511‐3p, which might contribute to the protective effect of miR‐511‐3p. Plasma levels of miR‐511‐3p were significantly lower in human asthmatic patients compared with nonasthmatic subjects. Conclusion: These studies support a critical but previously unrecognized role of MRC1 and miR‐511‐3p in protection against allergen‐induced lung inflammation.

The L60V Variation in Hepatitis B Virus Core Protein Elicits New Epitope-Specific Cytotoxic T Lymphocytes and Enhances Viral Replication

ABSTRACT Mutations in the core protein (HBc) of hepatitis B virus (HBV) are associated with aggressive hepatitis and advanced liver diseases in chronic hepatitis B (CHB). In this study, we identified the L60V variation in HBc that generates a new HLA-A2-restricted CD8+ T cell epitope by screening an overlapping 9-mer peptide pool covering HBc and its variants. The nonameric epitope V60 was determined by structural and immunogenic analysis. The HBc L60V variation is correlated with hepatic necroinflammation and higher viral levels, and it may be associated with a poor prognosis in CHB patients. Immunization with the defined HBV epitope V60 peptide elicited specific cytotoxic T lymphocyte (CTL)-induced liver injury in HLA-A2+ HBV transgenic mice. In addition, in vitro and in vivo experiments both demonstrated that the HBc L60V variation facilitates viral capsid assembly and increases HBV replication. These data suggest that the HBc L60V variation can impact both HBV replication and HBV-specific T cell responses. Therefore, our work provides further dissection of the impact of the HBc L60V variation, which orchestrates HBV replication, viral persistence, and immunopathogenesis during chronic viral infection.