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In clinic, there is still no drug that can significantly improve the survival rate of patients with acute liver failure (ALF). We have confirmed that recombinant human IL-1 receptor antagonist (rhIL-1Ra) significantly improves the survival rate of acetaminophen (APAP)-induced ALF mice by reducing hepatocellular apoptosis. Here, we investigated the mechanism of this and the key target cells of rhIL-1Ra. In vivo, APAP-induced ALF mice were treated with rhIL-1Ra and gadolinium chloride (Gdcl3), respectively. Survival rates of mice, serum IL-1Ra and IL-1β levels, IL-1 receptor type I (IL-1RI) and CD163 expression in the livers, and the phagocytic activities of Kupffer cells (KCs) were investigated. Additionally, the proliferation of hepatocytes and KCs in co-culture conditions with the serum of ALF mice were investigated in vitro. In this study, a large number of activated large KCs were found in liver lobe region III. Both GdCl3 and rhIL-1Ra significantly decreased the quantity of large KCs. In all of the mice, hepatocytes and liver non-parenchymal cells other than KCs expressed low levels of IL-1RI, whereas large KCs expressed high levels of IL-1RI. The high ratio of endogenous IL-1Ra/IL-1β was related to rhIL-1Ra function. Additionally, the phagocytic activities of KCs were significantly inhibited by GdCl3 and rhIL-1Ra. In vitro, the proliferation of hepatocytes in co-culture conditions were significantly inhibited by KCs. In conclusion, large KCs were the key target cells of rhIL-1Ra, and rhIL-1Ra could play its role of reducing hepatocellular apoptosis mainly by inhibiting the activities of KCs.

Background/Aims: Developing engineered dendritic cell (DC)-targeting lentivectors (LVs) have been the target of intense research for their potential to create antigen-directed immunotherapeutics which can be safely administered to patients. In this study, we constructed a DC-directed LV (LVDC-UbHBcAg-LIGHT) as a potential vaccine to induce anti-HBV immune responses. Methods: Specificity of LVDC-UbHBcAg-LIGHT for DCs in vivo was confirmed through live animal imaging studies. The levels of cytokine production in T cells were assessed by flow cytometry. The HBcAg-specific cytotoxic T lymphocyte (CTL) responses and antibody responses induced by direct administration of the LVs were detected by LDH release assay and ELISA respectively. The levels of serum HBsAg and HBV DNA were evaluated by Abbott kits and quantitative PCR respectively. The expression levels of HBsAg and HBcAg in liver tissues of HBV transgenic mice were examined by immunohistochemistry. In addition, molecular mechanism underlying the activation of CD8+ T cells was explored. Results: Live animal imaging studies showed that following subcutaneous administration of LVDC-UbHBcAg-LIGHT, no obvious luminescence signal was detected at the injection site. Immunization with LVDC-UbHBcAg-LIGHT elicited potent T cell responses in HBV transgenic mice evidenced by increased percentages of IFN-γ, TNF-α and GzmB producing CD8+ T cells as well as IFN-γ producing CD4+ T cells, improved HBcAg-specific CTL activities and antibody responses. Additionally, vaccination with LVDC-UbHBcAg-LIGHT efficiently reduced serum HBsAg, HBV DNA levels and the expression of HBsAg and HBcAg in liver tissues of HBV transgenic mice. More importantly, autophagy was induced in the activated CD8+ T cells, and the induced autophagy noticeably promoted the proliferation of T cells and decreased the frequencies of apoptotic CD8+ T cells by selectively degrading ubiquitinated apoptosis and cell cycle-associated protein aggregates. Futhermore, we confirmed the interaction between autophagosomes and ubiquitinated aggregates by confocal microscopy and immunoprecipitation analysis. Conclusions: These results demonstrated that LVDC-UbHBcAg-LIGHT provided a simple method of eliciting effective antiviral immune responses in HBV transgenic mice and might potentially be used as a therapeutic strategy to eradicate HBV with more safety and efficiency. Moreover, our results revealed a direct role of autophagy in promoting the survival and proliferation of activated CD8+ T cells.

Interleukin-1 (IL-1) family and Kupffer cells are linked with liver regeneration, but their precise roles remain unclear. IL-1 family members are pleiotropic factors with a range of biological roles in liver diseases, inducing hepatitis, cirrhosis, and hepatocellular carcinoma, as well as liver regeneration. Kupffer cells are the main source of IL-1 and IL-1 receptor antagonist (IL-1Ra), the key members of IL-1 family. This systemic review highlights a close association of IL-1 family members and Kupffer cells with liver regeneration, although their specific roles are inconclusive. Moreover, IL-1 members are proposed to induce effects on liver regeneration through Kupffer cells.

Dendritic cells (DCs) play a predominant role in initiating cell immune responses. Here we generated a DC-targeting lentiviral vector (LVDC-UbHBcAg-LIGHT) and evaluated its capacity to elicit HBV-specific cytotoxic T lymphocyte (CTL) responses. DC-SIGN-mediated specific transduction using this construct was confirmed in DC-SIGN-expressing 293T cells and ex vivo-cultured bone marrow cells. LVDC-UbHBcAg-LIGHT-loaded DCs were highly effective in inducing HBV-specific CTLs. Mechanistic studies demonstrated autophagy blocking led to a significant increase in apoptosis and obvious inhibition of CD8 + T cells entry into S-phase, correspondingly attenuated LVDC-UbHBcAg-LIGHT-loaded DC-induced T cell responses. This observation was supported by accumulation of pro-apoptotic proteins and the main negative cell cycle regulator-CDKN1B that otherwise would be degraded in activated T cells where autophagy preferentially occured. Our findings revealed an important role of autophagy in the activation of T cells and suggested LVDC-UbHBcAg-LIGHT may potentially be used as a therapeutic strategy to combat persistent HBV infection with higher security.

Cholestasis leads to acute hepatic injury, fibrosis/cirrhosis, inflammation, and duct proliferation. We investigated whether blocking receptor of advanced glycation end-products (RAGE) with polyclonal anti-RAGE antibodies (anti-RAGE) could regulate acute liver injury and fibrosis in a rat bile duct ligation (BDL) model. Male Wister rats received 0.5mg/kg rabbit anti-RAGE or an equal amount of rabbit IgG by subcutaneous injection twice a week after BDL. Samples of liver tissue and peripheral blood were collected at 14 days after BDL. Serum biochemistry and histology were used to analyze the degree of liver injury. Quantitative real-time PCR (qPCR) and immunohistochemical staining were used to further analyze liver injury. Anti-RAGE improved the gross appearance of the liver and the rat survival rate. Liver tissue histology and relevant serum biochemistry indicated that anti-RAGE attenuated liver necrosis, inflammation, liver fibrosis, and duct proliferation in the BDL model. qPCR and western blotting showed significant reductions in interleukin-1β expression levels in the liver by treatment with anti-RAGE. Anti-RAGE also significantly reduced the mRNA levels of α1(1) collagen (Col1α1) and cholesterol 7α-hydroxylase, and the ratio of tissue inhibitor of matrix metalloproteinase-1 to matrix metalloproteinases (MMPs) in the liver. In addition, anti-RAGE regulated the transcriptional level of Col1α1 and MMP-9 in transforming growth factor-β-induced activated LX-2 cells in vitro. Anti-RAGE was found to inhibit hepatic stellate cell proliferation in vivo and in vitro. Therefore, anti-RAGE can protect the liver from injury induced by BDL in rats.