Anti-inflammatory and antioxidative properties of helicid protect against CCl4 induced acute liver injury in mice

Taraxasterol extracted from Ixeridium gramineum (Fisch.) Tzvel. Attenuated D-GalN/LPS-induced fulminant hepatitis by modulating the JAK/STAT and TNF signalling pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Taraxasterol (TAR), a compound highly abundant and easily obtainable from Tibetan medicine Ixeridium gramineum (Fisch.) Tzvel., exhibits a variety of biological effects, including hepatoprotective, anti-inflammatory, and antioxidant activities.

AIM OF THE STUDY

To investigated the protective role and underlying mechanisms of TAR in fulminant hepatitis (FH) through the regulation of oxidative stress, inflammatory responses, and apoptosis by modulating the JAK/STAT and TNF signalling pathways.

MATERIAL AND METHODS

The study used Kunming mice to establish a D-GalN/LPS-induced FH model, which was divided into the following groups: Control group, D-GalN/LPS group, D-GalN/LPS + Silymarin group, D-GalN/LPS + TAR 2.5 group, D-GalN/LPS + TAR 5 group, D-GalN/LPS + TAR 10 group, and TAR 10 group. H&E staining and biochemical analyses were employed to evaluate liver pathological changes. Oxidative stress factors and inflammatory response were assessed via ELISA. RNA sequencing analysis was used to detect changes in inflammatory factor genes and apoptosis genes with TAR intervention in liver tissues. The distribution of the proteins p-STAT3 and p-JNK in liver tissues was ascertained using immunohistochemical staining. In vitro experiments were conducted on RAW264.7 cells exposed to LPS and TAR. Apoptosis was evaluated via flow cytometry and Hoechst 33258 staining. Immunofluorescence staining was employed to determine the protein expression levels of p-STAT3 and p-JNK in RAW264.7 cells. Gene and protein expression in the JAK/STAT and TNF signalling pathways, as well as apoptosis, were analyzed using qRT-PCR and Western blotting.

RESULTS

TAR effectively reduced hepatocyte necrosis, diminished inflammatory factor release, inhibited oxidative stress, significantly decreased the apoptosis of RAW264.7 cells, inhibited the protein expressions of p-JAK2, p-STAT3, p-MEK4, p-JNK, Caspase-3, Caspase-8, and Bax, and increased the protein expressions of SOCS3 and Bcl-2.

CONCLUSION

TAR prevents D-GalN/LPS-induced FH by regulating the JAK/STAT and TNF signalling pathways and apoptosis, demonstrating its therapeutic potential in treating liver diseases.

Combination of Houttuynia cordata polysaccharide and Lactiplantibacillus plantarum P101 alleviates acute liver injury by regulating gut microbiota in mice

BACKGROUND

Polysaccharides and probiotics can play an outstanding role in the treatment of liver disease by regulating gut microbiota. Recently, the combined therapeutic effect of probiotics and polysaccharides has attracted the attention of researchers. Houttuynia cordata polysaccharide (HCP) combined with Lactiplantibacillus plantarum P101 was used to prevent carbon tetrachloride (CCl₄ )-induced acute liver injury (ALI) in mice, and its effect on gut microbiota regulation was explored.

RESULTS

Results showed that, in mice, HCP combined with L. plantarum P101 significantly alleviated oxidative stress and inflammatory injury in the liver by activating Nrf2 signals and inhibiting NF-κB signals. The analysis of gut microbiota revealed that the combination of HCP and L. plantarum P101 increased the abundance of beneficial bacteria such as Alloprevotella, Roseburia, and Akkermansia, but reduced that of the pro-inflammatory bacteria Alistipes, Enterorhabdus, Anaerotruncus, and Escherichia-Shigella. Correlation analysis also indicated that the expression of Nrf2 and TLR4/NF-κB was connected to the changes in gut microbiota composition. Houttuynia cordata polysaccharide combined with L. plantarum P101 can regulate the gut microbiota and then mediate the gut-liver axis to activate the antioxidant pathway and inhibit inflammatory responses, thereby alleviating CCl₄ -induced ALI.

CONCLUSION

Our study provided a new perspective on the use of polysaccharides combined with probiotics in the treatment of liver disease. © 2022 Society of Chemical Industry.

Puerarin Prevents Acute Liver Injury via Inhibiting Inflammatory Responses and ZEB2 Expression

Puerarin, an isoflavone component extracted from herb radix puerariae, is widely used in China in the treatment of immune diseases and inflammation. Previous studies have demonstrated that puerarin prevented acute lung injury by regulating inflammatory responses. However, the effect of puerarin on acute liver injury (ALI) was unclear. The purpose of this study was to explore the beneficial effects of puerarin when applied to ALI. We found that puerarin inhibited liver injury and inflammatory cell infiltration in lipopolysaccharide (LPS)/D-galactose (D-Gal)-induced acute liver failure and the liver pro-inflammatory cytokines interleukin (IL)-1β, IL-6, and tumor necrosis factor-alpha (TNF-α) in liver tissues with ALI and LPS-induced L-02 cells but upregulated the expression level of zinc finger E-box-binding homeobox 2 (ZEB2). Significantly, the results of this study showed that the inhibition of liver pro-inflammatory cytokine (IL-1β, IL-6, and TNF-α) production in LPS-induced L-02 cells was caused by ZEB2 overexpression. However, knocking down ZEB2 promoted LPS-mediated secretion of liver pro-inflammatory cytokines in L-02 cells. Additional experiments showed that puerarin inhibited the activation of the NF-κB signaling pathway by elevating ZEB2 expression in L-02 cells. In summary, puerarin most likely prevented activation of the pro-inflammatory factors and reduced LPS/D-Gal-induced liver injury by enhancing the ZEB2 expression level and, consequently, blocking activation of the NF-κB signaling pathway in the liver.

Orphan nuclear receptor ERRγ regulates hepatic TGF-β2 expression and fibrogenic response in CCl4-induced acute liver injury

Acute liver injury results from the complex interactions of various pathological processes. The TGF-β superfamily plays a crucial role in orchestrating fibrogenic response. In contrast to TGF-β1, a role of TGF-β2 in hepatic fibrogenic response has not been fully investigated. In this study, we showed that TGF-β2 gene expression and secretion are induced in the liver of CCl₄ (1 ml/kg)-treated WT mice. Studies with hepatocyte specific ERRγ knockout mice or treatment with an ERRγ-specific inverse agonist, GSK5182 (40 mg/kg), indicated that CCl₄-induced hepatic TGF-β2 production is ERRγ dependent. Moreover, IL6 was found as upstream signal to induce hepatic ERRγ and TGF-β2 gene expression in CCl₄-mediated acute toxicity model. Over-expression of ERRγ was sufficient to induce hepatic TGF-β2 expression, whereas ERRγ depletion markedly reduces IL6-induced TGF-β2 gene expression and secretion in vitro and in vivo. Promoter assays showed that ERRγ directly binds to an ERR response element in the TGF-β2 promoter to induce TGF-β2 transcription. Finally, GSK5182 diminished CCl₄-induced fibrogenic response through inhibition of ERRγ-mediated TGF-β2 production. Taken together, these results firstly demonstrate that ERRγ can regulate the TGF-β2-mediated fibrogenic response in a mouse model of CC1₄-induced acute liver injury.