Chun-Qiu Hao

Inhibition of connective tissue growth factor suppresses hepatic stellate cell activation in vitro and prevents liver fibrosis in vivo

Activation of hepatic stellate cells (HSC) represents a critical event in fibrosis, and connective tissue growth factor (CTGF) plays a profibrotic activity and a key factor in the pathogenesis of tissue fibrosis. The current study aimed to determine whether lentivirus-mediated short hairpin RNA (shRNA)–targeted CTGF downregulates the CTGF expression and furthermore whether it suppresses the activation and proliferation of HSC in vitro and prevents liver fibrosis in vivo. HSC-T6 cells were treated with recombinant lentivirus carrying CTGF siRNA. Real-time PCR, Western blotting, MTT, and flow cytometry were performed to investigate the activation and proliferation of HSC-T6 cells in response to CTGF silence. CCl4-induced rats were received lentivirus containing CTGF siRNA by intraportal vein injection. Levels of liver fibrosis were assessed by biochemical and histopathologic examinations. Recombinant lentivirus containing CTGF siRNA could effectively and specifically downregulate the expression of CTGF in both HSC-T6 cells and CCl4-induced rats with liver fibrosis. Blockade of CTGF resulted in significant inhibition of HSC activation and proliferation with decrease in TIMPs, MMP2, MMP9, and collagen I, as well as increase in cells in S phase. Silencing CTGF expression with siRNA prevented liver fibrosis in CCl4-induced rat model. These findings indicated that CTGF plays a key role in the pathogenesis of liver fibrosis and lentiviral-mediated CTGF siRNA has the potential to be an effective treatment for liver fibrosis.

Imbalance of regulatory T cells and T helper type 17 cells in patients with chronic hepatitis C.

Pegylated interferon and ribavirin combination therapy is known to be effective in suppressing viral replication in 50–60% of hepatitis C virus (HCV) ‐infected patients. However, HCV‐infected patients often exhibit varied responses to therapy. Therefore, the identification of immunological markers associated with the clinical outcomes of antiviral treatment is critical for improvement of therapeutic options. In this study, we aimed to investigate the ratio of CD4+ CD25+ FoxP3+ regulatory T (Treg) cells to interleukin‐17A (IL‐17A) ‐producing T helper type 17 (Th17) cells, and its association with clinical outcomes in response to anti‐HCV treatment. In all, 114 patients with HCV infection received pegylated interferon‐α2a and ribavirin therapy for 48 weeks, and the frequency of Treg cells and Th17 cells as well as the levels of secreted cytokines were longitudinally analysed by flow cytometry and ELISA. Treg cell proportions and IL‐10 production were significantly elevated in HCV‐infected patients, especially for HCV genotype 1b. However, the frequency of Th17 cells as well as the secretion of IL‐17, IL‐22 and IL‐23 did not reveal notable difference between HCV infections and healthy individuals. Inhibition of HCV replication was accompanied by a reduction in Treg cells, but little influence on Th17 cells, which led to a significant decrease in Treg : Th17 ratios. Skewed Treg : Th17 ratios existed in chronic hepatitis C. HCV RNA load is closely associated with Treg : Th17 ratios during pegylated interferon‐α2a and ribavirin treatment in HCV‐infected patients. The imbalance of Treg cells to Th17 cells might play an important role in persistent HCV infection.

Notch Signaling Contributes to Liver Inflammation by Regulation of Interleukin-22-Producing Cells in Hepatitis B Virus Infection

The mechanism of hepatitis B virus (HBV) induced liver inflammation is not fully elucidated. Notch signaling augmented interleukin (IL)-22 secretion in CD4+ T cells, and Notch-IL-22 axis fine-tuned inflammatory response. We previously demonstrated a proinflammatory role of IL-22 in HBV infection. Thus, in this study, we analyzed the role of Notch in development of IL-22-producing cells in HBV infection by inhibition of Notch signaling using γ-secretase inhibitor DAPT in both hydrodynamic induced HBV-infected mouse model and in peripheral blood cells isolated from patients with HBV infection. mRNA expressions of Notch1 and Notch2 were significantly increased in livers and CD4+ T cells upon HBV infection. Inhibition of Notch signaling in vivo leaded to the reduction in NKp46+ innate lymphoid cells 22 (ILC22) and lymphoid tissue inducer 4 (LTi4) cells in the liver. This process was accompanied by downregulating the expressions of IL-22 and related proinflammatory cytokines and chemokines in the liver, as well as blocking the recruitment of antigen-non-specific inflammatory cells into the liver and subsequent liver injury, but did not affect HBV antigens production and IL-22 secretion in the serum. Furthermore, IL-22 production in HBV non-specific cultured CD4+ T cells, but not HBV-specific CD4+ T cells, was reduced in response to in vitro inhibition of Notch signaling. In conclusion, Notch siganling appears to be an important mediator of the liver inflammation by modulating hepatic ILC22. The potential proinflammatory effect of Notch-mediated ILC22 may be significant for the development of new therapeutic approaches for treatment of hepatitis B.

Kinetics of Th17 Cytokines During Telbivudine Therapy in Patients With Chronic Hepatitis B

Th17 cells and the secreting cytokines play an important role in the immune response and inflammation that is induced by hepatitis B virus (HBV). However, it remains not fully elucidated how the antiviral agents affect Th17 cytokines and signal pathway. Telbivudine therapy has been proved to inhibit HBV replication effectively and to improve clinical outcome of chronic hepatitis B (CHB). Thus, in this study, the effect of decrease in viral load and liver dysfunction resulting from telbivudine treatment on Th17 cells and the related cytokines IL-17, IL-22, and IL-23 were analyzed. Peripheral blood mononuclear cells and serum from twenty-four CHB patients were harvested at 0, 12, 24, 36, and 48 weeks after initiation of telbivudine treatment. In parallel to the reduction of HBV DNA and normalization of serum ALT, significant declines in circulating HBV-specific Th17 cells and IL-22 production were found during antiviral therapy. The expression of serum IL-22 and IL-23, but not IL-17 also decreased during therapy. Our findings suggest that antiviral effect of telbivudine may attribute to both direct virus inhibition and regulation of inflammation, which further improve the understanding of pathogenesis of HBV infection and develop antiviral strategy for controlling viral hepatitis.

Role of A20 in interferon-α-mediated functional restoration of myeloid dendritic cells in patients with chronic hepatitis C

Hepatitis C virus (HCV) infection is a global health problem characterized by a high rate of chronic infection, which may in part be due to a defect in myeloid dendritic cells (mDCs). This defect appears to be remedied by treatment with interferon‐α (IFN‐α) ‐based antiviral therapies; however, the molecular mechanisms underlying mDC dysfunction in HCV infection and restoration by IFN‐α treatment are unclear. The ubiquitin‐editing protein A20 plays a crucial role in controlling the maturation, cytokine production and immunostimulatory function of mDCs. We propose that the expression of A20 correlates with the function of mDCs during HCV infection and IFN‐α therapy. In this study, we observed that A20 expression in mDCs isolated from chronically HCV‐infected subjects was significantly higher than healthy subjects or subjects achieving sustained virological responses (SVR) following antiviral treatment. Notably, A20 expression in mDCs from HCV patients during IFN‐α treatment was significantly lower than for untreated patients, SVR patients, or healthy subjects. Besides, A20 expression in mDCs stimulated by polyI:C differed between HCV patients and healthy subjects, and this difference could be abrogated by the treatment with IFN‐α in vitro. Additionally, A20 expression by polyI:C‐activated mDCs, with or without IFN‐α treatment, negatively correlated with the expression of HLA‐DR, CD86 and CCR7, and the secretion of interleukin‐12 (IL‐12), but positively associated with the production of IL‐10. Importantly, silencing A20 expression using small interfering RNAs increased the production of IL‐12 in mDCs of chronically HCV‐infected individuals. These findings suggest that A20 plays a crucial role in negative regulation of innate immune responses during chronic viral infection.

CD100 Up-Regulation Induced by Interferon-α on B Cells Is Related to Hepatitis C Virus Infection

Objectives CD100, also known as Sema4D, is a member of the semaphorin family and has important regulatory functions that promote immune cell activation and responses. The role of CD100 expression on B cells in immune regulation during chronic hepatitis C virus (HCV) infection remains unclear. Materials and Methods We longitudinally investigated the altered expression of CD100, its receptor CD72, and other activation markers CD69 and CD86 on B cells in 20 chronic HCV-infected patients before and after treatment with pegylated interferon-alpha (Peg-IFN-α) and ribavirin (RBV) by flow cytometry. Results The frequency of CD5+ B cells as well as the expression levels of CD100, CD69 and CD86 was significantly increased in chronic HCV patients and returned to normal in patients with sustained virological response after discontinuation of IFN-α/RBV therapy. Upon IFN-α treatment, CD100 expression on B cells and the two subsets was further up-regulated in patients who achieved early virological response, and this was confirmed by in vitro experiments. Moreover, the increased CD100 expression via IFN-α was inversely correlated with the decline of the HCV-RNA titer during early-phase treatment. Conclusions Peripheral B cells show an activated phenotype during chronic HCV infection. Moreover, IFN-α therapy facilitates the reversion of disrupted B cell homeostasis, and up-regulated expression of CD100 may be indirectly related to HCV clearance.

Modulation of Tim-3 Expression by Antigen-Dependent and -Independent Factors on T Cells from Patients with Chronic Hepatitis B Virus Infection

T-cell immunoglobulin domain and mucin domain-containing molecule-3 (Tim-3) was up-regulated on viral specific T cells and contributed to T cells exhaustion during chronic hepatitis B virus (HBV) infection. However, modulation of Tim-3 expression was still not fully elucidated. To evaluate the potential viral and inflammatory factors involved in the inductor of Tim-3 expression on T cells, 76 patients with chronic HBV infection (including 40 chronic hepatitis B [CHB] and 36 asymptomatic HBV carriers [AsC]) and 40 of normal controls (NCs) were enrolled in this study. Tim-3 expressions on CD4+ and CD8+ T cells were assessed in response to HBV-encoding antigens, HBV peptide pools, and common γ-chain (γc) cytokines stimulation by flow cytometry. HBV peptides and anti-CD3/CD28 directly induced Tim-3 expression on T cells. γc cytokines also drive Tim-3 up-regulations on both CD4+ and CD8+ T cells in patients with chronic HBV infection. However, γc cytokines did not enhance the Tim-3 inductions by either anti-CD3/CD28 or HBV peptides stimulation. Furthermore, γc cytokines-mediated Tim-3 induction could not be abrogated by γc cytokine receptor-neutralizing antibodies. The current results suggested that elevation of Tim-3 expression on T cells could be regulated by both antigen-dependent and -independent manner in patients with chronic HBV infection. The role of γc cytokines in modulation of inhibitory pathway might be evaluated as immunotherapies in humans.

Therapeutic effect of RANTES–KDEL on inhibition of HIV-1 in CD34+ human hematopoietic stem cells (hHSC)

Cell surface receptors, such as the CCR5 chemokine receptors, represent key determinants of the human immunodeficiency virus type 1 (HIV-1) entry into target cells. The CC-chemokine, RANTES (regulated upon activation, normal T-cell expressed and secreted), a ligand for CCR5, have been targeted to the lumen of endocytoplasmic reticulum (ER) using a KDEL (ER-retention signal) fusion termed RANTES-KDEL and this construct was found to prevent effectively transport of newly synthesized CCR5 to the cell surface. Lentiviral vectors have emerged as potent and versatile tools of gene transfer for basic and applied research are able to transduce nondividing cells and maintain sustained long-term expression of transgenes. For this reason, an HIV-based lentiviral vector expressing RANTES-KDEL, pLenti6/V5-R-K, was constructed and then cotransfected with the ViraPower Packaging Mix (pLP1, pLP2, and pLP/VSVG) into 293FT cells to produce a replication-incompetent lentivirus stock. The lentiviral stock was titrated using HeLa cells, and the expression of the gene of interest, RANTES, was detected by indirect immunofluorescence. Based on the above results, the lentiviral stock was transduced into CD34(+) human hematopoietic stem cells (hHSC) separated magnetically from the cord blood (the purity was 96.8% evaluated by flow cytometry). Finally, the levels of p24 in the cultures of pLenti6/V5-R-K-transduced CD34(+) hHSC were detected after infection by HIV-1 DP1 (a R5-tropic HIV-1 strain, which was isolated by the Centers for Disease Control and Prevention of China in Henan province in 2000 from a Chinese man who had asymptomatic HIV-1 infection with a history of blood transfusions). It was shown that pLenti6/V5-R-K transduction inhibited expression of the DP1 p24 antigen by 51%, 58% and 60% on the 4th, 7th and 10th day respectively (P<0.05).

Interferon-α-Enhanced CD100/Plexin-B1/B2 Interactions Promote Natural Killer Cell Functions in Patients with Chronic Hepatitis C Virus Infection

Background CD100, also known as Sema4D, is an immune semaphorin constitutively expressed on natural killer (NK) cells and T cells. As an immune activation molecule, CD100 has important immunoregulatory effects on NK functions by enhancing the interactions between NK cells and target cells. The aim of this study was to investigate whether hepatitis C virus (HCV) infection affects CD100 expression, and whether interferon-α treatment enhances NK killing activity to facilitate HCV clearance via CD100. Methods Expression of CD100 on NK cells was evaluated by flow cytometry in patients with chronic HCV infection, with or without pegylated interferon-α-based therapy. NK cell cytotoxicity and interferon (IFN)-γ production were measured by flow cytometry upon culturing the NK cells with K562 and Huh7.5 or HCV JFH-1-infected Huh7.5 cells. Results The frequency of CD100+ NK cells in HCV-infected individuals was slightly suppressed compared to healthy subjects. IFN-α treatment could significantly upregulate CD100 expression, which was confirmed by in vitro studies using peripheral blood mononuclear cells cocultured with HCV-expressing Huh7.5 cells or IFN-α. Importantly, the expression of CD100 on NK cells from HCV patients was inversely associated with the HCV-RNA levels in the early phase of IFN-α therapy, and the IFN-α upregulated CD100 led to an enhanced NK killing activity through ligations with its receptors plexin-B1/B2 on target cells. Conclusion These results implied a novel mechanism by which IFN-α enhanced CD100/Plexin-B1/B2 interaction plays an important role in promoting NK functions in patients with chronic hepatitis C.

The Efficacy of Add-on Telbivudine Versus Switching to Pegylated Interferon Alfa-2a in Chronic Hepatitis B Patients With Poor Responses to Adefovir

Background: There are limited options for chronic hepatitis B (CHB) patients who have poor responses to adefovir (ADV). Objectives: The aim of this study is to evaluate the effects of adding on telbivudine (LdT) or switching to pegylated interferon alfa-2a (PEG-IFN-α2a) as alternative rescue therapies for patients with poor responses to the initial ADV treatments. Patients and Methods: Ninety-seven CHB patients with HBV DNA > 2 log10 copies/mL 48 weeks after ADV monotherapy were included in this study. Fifty-nine of these patients were treated with a combination of LdT plus ADV (LdT + ADV) daily, while thirty-eight patients were switched to PEG-IFN-α2a subcutaneous injections weekly for 48 weeks. Results: Both rescue strategies were proven to be safe and the majority of patients tolerated the therapies well. LdT + ADV led to more rapid reductions in viral loads than PEG-IFN-α2a monotherapy, with 2.14 (LdT + ADV) and 0.98 (PEG-IFN-α2a) log10 copies/mL decreases 48 weeks after rescue treatments, respectively (P < 0.00001). The rates corresponding to virological and biochemical responses were also elevated in patients who received the LdT + ADV combination therapy at the end of the observation period (88.1 vs. 68.4% for virological response, P = 0.017; 83.3 vs. 47.2%, P = 0.00045). However, the decline in the hepatitis B surface antigen (HBsAg) was more pronounced in PEG-IFN-α2a treated patients. Moreover, the cumulative rates of serological responses were higher in patients who switched to the PEG-IFN-α2a therapy. Conclusions: Both add-on LdT and switching to PEG-IFN-α2a were satisfactory and optimal treatments for CHB patients with poor responses to ADV. Both rescue strategies resulted in significant reductions in serum viral load and ALT levels, and were associated with high rate of serological outcomes in our hospital.