Exogenous activation of toll-like receptor 5 signaling mitigates acetaminophen-induced hepatotoxicity in mice

Nuciferine Effectively Protects Mice against Acetaminophen-Induced Liver Injury

Acetaminophen (APAP) overdose still poses a major clinical challenge and is a leading cause of acute liver injury (ALI). N-acetylcysteine (NAC) is the only approved antidote to treat APAP toxicity while NAC therapy can trigger side effects including severe vomiting and even shock. Thus, new insights in developing novel therapeutic drugs may pave the way for better treatment of APAP poisoning. Previous research has reported that nuciferine (Nuci) possesses anti-inflammatory and antioxidant properties. Therefore, the objective of this study was proposed to investigate the hepatoprotective effects of Nuci and explore its underlying mechanisms. Mice were intraperitoneally (i.p.) administered with APAP (300 mg/kg) and subsequently injected with Nuci (25, 50, and 100 mg/kg, i.p.) at 30 min after APAP overdose. Then, all mice were sacrificed at 12 h after APAP challenge for further analysis. Nuci-treated mice did not show any side effects and our results revealed that treating Nuci significantly attenuated APAP-induced ALI, as confirmed by histopathological examinations, biochemical analysis, and diminished hepatic oxidative stress and inflammation. The in silico prediction and mRNA-sequencing analysis were performed to explore the underlying mechanisms of Nuci. GO and KEGG enrichment of the predicted target proteins of Nuci includes reactive oxygen species, drug metabolism of cytochrome P450 (CYP450) enzymes, and autophagy. Furthermore, the mRNA-sequencing analyses indicated that Nuci can regulate glutathione metabolic processes and anti-inflammatory responses. Consistently, we found that Nuci increased the hepatic glutathione restoration but decreased APAP protein adducts in damaged livers. Western blot analysis further confirmed that Nuci effectively promoted hepatic autophagy in APAP-treated mice. However, Nuci could not affect the expression levels of the main CYP450 enzymes (CYP1A2, CYP2E1, and CYP3A11). These results demonstrated that Nuci may be a potential therapeutic drug for APAP-induced ALI via amelioration of the inflammatory response and oxidative stress, regulation of APAP metabolism, and activation of autophagy.

Inhibition of the B7-H3 immune checkpoint limits hepatocellular carcinoma progression by enhancing T lymphocyte-mediated immune cytotoxicity in vitro and in vivo

PURPOSE

The interaction between tumor cells and immune system in hepatocellular carcinoma (HCC) remains unclear. Great clinical achievements have progressed in HCC patients treated with immune checkpoint inhibitors (ICIs) for programmed death-1 and its ligands. However, response efficacy for these therapies is limited, thereby requiring alternative ICI candidates for HCC treatment. B7 homolog 3 protein (B7-H3), an immunoregulatory protein, plays a significant role in tumor immunity and disease progression. In this study, we evaluated the correlation between B7-H3 expression and prognosis of HCC patients, and investigated the therapeutic potential of B7-H3 targeting in HCC.

METHODS

B7-H3 expression was analyzed immunohistochemically in HCC patients, and its relationship with tumor-infiltrating lymphocyte infiltration was assessed. The anti-tumor efficacy of anti-B7-H3 antibody therapy was determined using an in vitro co-culture system and a subcutaneous HCC-bearing murine model.

RESULTS

We found that B7-H3 overexpressed in tumor cells and positively correlated with poor prognosis in HCC patients. B7-H3 inhibited the infiltration of CD8⁺ T cells in tumors. Furthermore, co-culture experiment indicated that inhibiting B7-H3 in tumor cells significantly increased T cells-mediated immune activities and tumor cell killing. Consistently, anti-B7-H3 antibody-treated HCC murine model showed decreased tumor size and enhanced anti-tumor immunity mediated by CD8⁺ T cells.

CONCLUSION

Altogether, our findings suggest that B7-H3 inhibition in tumor cells restores the immune cytotoxicity of T cells, which in turn promotes apoptosis of target cells. Therefore, B7-H3 serves as a key negative regulator in tumor immunity and the promising clinical utility of B7-H3-based immunotherapies for HCC treatment could be developed.

Sappanone A ameliorates acetaminophen-induced acute liver injury in mice

Sappanone A (SA), a homoisoflavonoid compound extracted from the heartwood of Caesalpinia sappan Linn., exerts anti-inflammatory and antioxidant activities. However, the effects of SA on acetaminophen (APAP) overdose-induced acute liver injury (ALI) have not been determined yet. This study aims to explore the protective effects of SA and the potential mechanisms of action. Mice were pretreated with SA (25, 50, and 100 mg/kg) by intraperitoneal (i.p.) injection for seven days prior to APAP (300 mg/kg, i.p.) administration. At 12 h after APAP injection, serum and liver samples were collected. Primary murine hepatocytes were used to investigate the underlying mechanisms. SA pretreatment dose-dependently attenuated APAP-induced ALI, as validated by reduced serum alanine/aspartate aminotransferase levels, histopathologic lesions, and oxidative stress. Consistently, pretreatment with SA reduced the formation of APAP protein adducts in damaged livers of mice. Mechanistically, SA could facilitate the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) and thus promote cellular glutathione (GSH) synthesis. The hepatoprotective outcomes provided by SA were significantly abolished by treatment with ML385, a Nrf2 inhibitor. Besides, anti-inflammatory property of SA reduced inflammatory reaction in injured livers of mice. Of note, posttreatment with SA reveals significant therapeutic influences against APAP-induced ALI in mice. Collectively, our findings demonstrated that pretreated-SA ameliorated APAP-mediated ALI in mice, at least in part, by reducing the generation of APAP protein adducts via Nrf2-enhanced GSH synthesis, and by diminishing hepatic inflammation. Therefore, SA could be a potential hepatoprotective agent for treating ALI.

Protective Effects of Interleukin-37 Expression against Acetaminophen-Induced Hepatotoxicity in Mice

Aim

Interleukin (IL)-37 is a new anti-inflammatory cytokine of the IL-1 family. This study aimed to determine the effects of IL-37 on acetaminophen (APAP)-induced liver injury.

Materials and Methods

IL-37 plasmids were injected into mice via a tail vein hydrodynamics-based gene delivery.

Results

Our results showed that IL-37 pretreatment significantly decreased serum alanine aminotransferase and aspartate aminotransferase levels, hepatic myeloperoxidase activity, and attenuated the histological liver damage. Compared to the APAP group, IL-37 administration decreased Kupffer cells numbers in the liver of APAP-induced hepatotoxicity in mice. Furthermore, IL-37 pretreatment reduced the expression of proinflammatory cytokines including tumor necrosis factor-α, IL-6, IL-17, and nuclear factor-κB (NF-κB) in APAP-induced mice.

Conclusion

These results demonstrate that delivery of IL-37 plasmid can ameliorate APAP-induced liver injury by reducing proinflammatory cytokines production and preventing the activation of the NF-κB signaling pathway. IL-37 may be a promising candidate against APAP-induced liver injury.

Enhanced therapeutic efficacy of a novel self-micellizing nanoformulation-loading fisetin against acetaminophen-induced liver injury

Aim: To evaluate the feasibility of using dipotassium glycyrrhizinate (DG) as a nanocarrier-loading fisetin (FIT) with strengthened treatment efficacies against liver injury induced by acetaminophen overdose. Methods: DG-FIT was prepared, and its efficacy against liver injury induced by acetaminophen overdose was evaluated. Results: DG-FIT was successfully fabricated with excellent physicochemical properties. DG-FIT could be easily dissolved in water to form a clear micelle solution with high FIT encapsulation efficiency. FIT in DG-FIT exhibited a dramatically improved aqueous solubility. DG-FIT improved intestinal permeation. Regarding in vivo efficacies, DG-FIT exhibited significant effect against acetaminophen overdose by suppressing oxidative stress and proinflammatory cytokines involved. Conclusion: DG-FIT formulation possibly represents a promising method for strengthening the efficacy of FIT against acetaminophen-induced liver injury.

Pattern recognition receptors in health and diseases

Pattern recognition receptors (PRRs) are a class of receptors that can directly recognize the specific molecular structures on the surface of pathogens, apoptotic host cells, and damaged senescent cells. PRRs bridge nonspecific immunity and specific immunity. Through the recognition and binding of ligands, PRRs can produce nonspecific anti-infection, antitumor, and other immunoprotective effects. Most PRRs in the innate immune system of vertebrates can be classified into the following five types based on protein domain homology: Toll-like receptors (TLRs), nucleotide oligomerization domain (NOD)-like receptors (NLRs), retinoic acid-inducible gene-I (RIG-I)-like receptors (RLRs), C-type lectin receptors (CLRs), and absent in melanoma-2 (AIM2)-like receptors (ALRs). PRRs are basically composed of ligand recognition domains, intermediate domains, and effector domains. PRRs recognize and bind their respective ligands and recruit adaptor molecules with the same structure through their effector domains, initiating downstream signaling pathways to exert effects. In recent years, the increased researches on the recognition and binding of PRRs and their ligands have greatly promoted the understanding of different PRRs signaling pathways and provided ideas for the treatment of immune-related diseases and even tumors. This review describes in detail the history, the structural characteristics, ligand recognition mechanism, the signaling pathway, the related disease, new drugs in clinical trials and clinical therapy of different types of PRRs, and discusses the significance of the research on pattern recognition mechanism for the treatment of PRR-related diseases.