Bicyclol Alleviates Signs of BDL-Induced Cholestasis by Regulating Bile Acids and Autophagy-Mediated HMGB1/p62/Nrf2 Pathway

Protective effect of MP-40 mitigates BDL-induced hepatic fibrosis by inhibiting the NLRP3-mediated pyroptosis

Background

Hepatic fibrosis and its associated consequences continue to pose a substantial global health challenge. Developing novel approaches to hepatic fibrosis management and prevention is critically necessary. Radix Paeoniae Alba (RPA) is widely used in Traditional Chinese Medicine (TCM) to treat various diseases. Our earlier research found that a bioactive component of RPA had a dose-dependent effect on anti-allergic asthma. RPA reduces allergic asthma by slowing the hepatic wind, according to "Treatise on Febrile Diseases". However, this bioactive fraction's pharmacological effects and mechanisms on the liver are unknown.

Aim

This study examined the bioactive fraction MP-40, the methanol extract of RPA (MRPA), on bile duct ligation (BDL) for its anti-hepatic fibrosis activity and potential mechanisms.

Methods

First, the effectiveness of MP-40 in treating BDL-induced hepatic fibrosis in mice and rats was evaluated through survival rates, ALT, AST HYP, and pathological changes. Molecular assays were performed using in vitro cultures of HSC-T6 activation. The expression of α-SMA and Collagen I evaluated fibro-tropic factors with HSC activation. Furthermore, the levels of pyroptosis were assessed by examining the expression of the pyroptosis-related proteins, including NLRP3, Cleaved Caspase-1, GSDMD-N, and 1L-1β. Additionally, the effective constituents of MP-40 were identified by extraction, separation, and identification. Finally, PF and TGG, as the delegate compounds of MP-40, were tested to confirm their inhibition effects on HSC-T6 activation.

Results

The findings demonstrated that MP-40 and MRPA could lower ALT, AST, and HYP levels, boost survival rates, and reduce liver damage in BDL mice and rats. Furthermore, MP-40 outperforms MRPA. MP-40 was proven to drastically diminish fibrotic α-SMA and Collagen I. The expression of pyroptosis-related proteins NLRP3, Cleaved Caspase-1, TGF-β1, GSDMD-N, and 1L-1β decreased. MP-40 inhibited the synthesis of pyroptosis-related proteins more effectively than MCC950 (an NLRP3-specific inhibitor). Monoterpene glycosides and tannins were shown to be the most potent MP-40 components. Finally, the delegate compounds MP-40, PF, and TGG were shown to have substantial inhibitory effects on HSC-T6 activation.

Conclusion

The results proved that MP-40 alleviates BDL-induced cholestatic hepatic fibrosis by inhibiting NLRP3-mediated pyroptosis. PF and TGG play a role in treating BDL-induced cholestatic hepatic fibrosis in MP-40.

Beneficial effects of hepatic cyclooxygenase-2 expression against cholestatic injury after common bile duct ligation in mice

BACKGROUND AND AIMS

Cyclooxygenase-2 (COX-2) is involved in different liver diseases, but little is known about the significance of COX-2 in cholestatic injury. This study was designed to elucidate the role of COX-2 expression in hepatocytes during the pathogenesis of obstructive cholestasis.

METHODS

We used genetically modified mice constitutively expressing human COX-2 in hepatocytes. Transgenic mice (hCOX-2-Tg) and their wild-type (Wt) littermates were either subjected to a mid-abdominal laparotomy or common bile duct ligation (BDL) for 2 or 5 days. Then, we explored the mechanisms underlying the role of COX-2 and its derived prostaglandins in liver function, and the synthesis and excretion of bile acids (BA) in response to cholestatic liver injury.

RESULTS

After BDL, hCOX-2-Tg mice showed lower grades of hepatic necrosis and inflammation than Wt mice, in part by a reduced hepatic neutrophil recruitment associated with lower mRNA levels of pro-inflammatory cytokines. Furthermore, hCOX-2-Tg mice displayed a differential metabolic pattern of BA synthesis that led to an improved clearance after BDL-induced accumulation. In addition, an enhanced response to the BDL-induced oxidative stress and hepatic apoptosis was observed. In vitro experiments using hepatic cells that stably express hCOX-2 confirmed the cytoprotective role of prostaglandin E2 against BA toxicity.

CONCLUSIONS

Taken together, our data indicate that constitutive expression of COX-2 in hepatocytes ameliorates cholestatic liver injury in mice by reducing inflammation and cell damage and by modulating BA metabolism, pointing to a role for COX-2 as a defensive response against cholestasis-derived BA accumulation and injury.

Detrimental Role of CXCR3 in α-Naphthylisothiocyanate- and Triptolide-Induced Cholestatic Liver Injury

The chemokine receptor CXCR3 is functionally pleiotropic, not only recruiting immune cells to the inflamed liver but also mediating the pathological process of cholestatic liver injury (CLI). However, the mechanism of its involvement in the CLI remains unclear. Both alpha-naphthylisothiocyanate (ANIT) and triptolide are hepatotoxicants that induce CLI by bile acid (BA) dysregulation, inflammation, and endoplasmic reticulum (ER)/oxidative stress. Through molecular docking, CXCR3 is a potential target of ANIT and triptolide. Therefore, this study aimed to investigate the role of CXCR3 in ANIT- and triptolide-induced CLI and to explore the underlying mechanisms. Wild-type mice and CXCR3-deficient mice were administered with ANIT or triptolide to compare CLI, BA profile, hepatic recruitment of IFN-γ/IL-4/IL-17+CD4+T cells, IFN-γ/IL-4/IL-17+iNKT cells and IFN-γ/IL-4+NK cells, and the expression of ER/oxidative stress pathway. The results showed that CXCR3 deficiency ameliorated ANIT- and triptolide-induced CLI. CXCR3 deficiency alleviated ANIT-induced dysregulated BA metabolism, which decreased the recruitment of IFN-γ+NK cells and IL-4+NK cells to the liver and inhibited ER stress. After triptolide administration, CXCR3 deficiency ameliorated dysregulation of BA metabolism, which reduced the migration of IL-4+iNKT cells and IL-17+iNKT cells and reduced oxidative stress through inhibition of Egr1 expression and AKT phosphorylation. Our findings suggest a detrimental role of CXCR3 in ANIT- and triptolide-induced CLI, providing a promising therapeutic target and introducing novel mechanisms for understanding cholestatic liver diseases.

Hepatoprotective agents in the management of intrahepatic cholestasis of pregnancy: current knowledge and prospects

Intrahepatic cholestasis of pregnancy (ICP) is characterized by unexplained distressing pruritus in the mother and poses significant risk to the fetus of perinatal mortality. Occurring in the second and third trimester, the serum bile acid and aminotransferase are usually elevated in ICP patients. Ursodeoxycholic acid (UDCA) is the first line drug for ICP but the effectiveness for hepatoprotection is to a certain extent. In ICP patients with severe liver damage, combination use of hepatoprotective agents with UDCA is not uncommon. Herein, we reviewed the current clinical evidence on application of hepatoprotective agents in ICP patients. The underlying physiological mechanisms and their therapeutic effect in clinical practice are summarized. The basic pharmacologic functions of these hepatoprotective medications include detoxification, anti-inflammation, antioxidation and hepatocyte membrane protection. These hepatoprotective agents have versatile therapeutic effects including anti-inflammation, antioxidative stress, elimination of free radicals, anti-steatohepatitis, anti-fibrosis and anti-cirrhosis. They are widely used in hepatitis, non-alcoholic fatty liver disease, drug induced liver injury and cholestasis. Evidence from limited clinical data in ICP patients demonstrate reliable effectiveness and safety of these medications. Currently there is still no consensus on the application of hepatoprotective agents in ICP pregnancies. Dynamic monitoring of liver biochemical parameters and fetal condition is still the key recommendation in the management of ICP pregnancies.

Bacteroides uniformis-induced perturbations in colonic microbiota and bile acid levels inhibit TH17 differentiation and ameliorate colitis developments

Inflammatory bowel disease (IBD) is associated with gut dysbiosis and can lead to colitis-associated malignancies. Bacteroides uniformis (Bu) regulates animal intestinal homeostasis; however, the mechanism by which it alleviates colitis in mice remains unknown. We investigated the effects of B. uniformis JCM5828 and its metabolites on female C57BL/6J mice with dextran sulfate sodium salt (DSS) induced colitis. Treatment with Bu considerably alleviated colitis progression and restored the mechanical and immune barrier protein expression. Additionally, Bu increased the abundance of the symbiotic bacteria Bifidobacterium and Lactobacillus vaginalis while decreasing that of pathogenic Escherichia-Shigella, and modulated intestinal bile acid metabolism. Bu largely regulated the expression of key regulatory proteins of the NF-κB and mitogen-activated protein kinase (MAPK) signaling pathways in colonic tissues and the differentiation of TH17 cells. However, Bu could not directly inhibit TH17 cell differentiation in vitro; it modulated the process in the lamina propria by participating in bile acid metabolism and regulating key metabolites (alpha-muricholic, hyodeoxycholic, and isolithocholic acid), thereby modulating the intestinal immune response. Our findings suggest that Bu or bile acid supplements are potential therapies for colitis and other diseases associated with intestinal barrier dysfunction.

Bicyclol attenuates high fat diet-induced non-alcoholic fatty liver disease/non-alcoholic steatohepatitis through modulating multiple pathways in mice

Introduction: The pathological progression of non-alcoholic fatty liver disease (NAFLD) is driven by multiple factors, and non-alcoholic steatohepatitis (NASH) represents its progressive form. In our previous studies, we found that bicyclol had beneficial effects on NAFLD/ NASH. Here we aim to investigate the underlying molecular mechanisms of the bicyclol effect on NAFLD/NASH induced by high-fat diet (HFD) feeding.

Methods: A mice model of NAFLD/NASH induced by HFD-feeding for 8 weeks was used. As a pretreatment, bicyclol (200 mg/kg) was given to mice by oral gavage twice daily. Hematoxylin and eosin (H&E) stains were processed to evaluate hepatic steatosis, and hepatic fibrous hyperplasia was assessed by Masson staining. Biochemistry analyses were used to measure serum aminotransferase, serum lipids, and lipids in liver tissues. Proteomics and bioinformatics analyses were performed to identify the signaling pathways and target proteins. Data are available via Proteome X change with identifier PXD040233. The real-time RT-PCR and Western blot analyses were performed to verify the proteomics data.

Results: Bicyclol had a markedly protective effect against NAFLD/NASH by suppressing the increase of serum aminotransferase, hepatic lipid accumulation and alleviating histopathological changes in liver tissues. Proteomics analyses showed that bicyclol remarkably restored major pathways related to immunological responses and metabolic processes altered by HFD feeding. Consistent with our previous results, bicyclol significantly inhibited inflammation and oxidative stress pathway related indexes (SAA1, GSTM1 and GSTA1). Furthermore, the beneficial effects of bicyclol were closely associated with the signaling pathways of bile acid metabolism (NPC1, SLCOLA4 and UGT1A1), cytochrome P450-mediated metabolism (CYP2C54, CYP3A11 and CYP3A25), biological processes such as metal ion metabolism (Ceruloplasmin and Metallothionein-1), angiogenesis (ALDH1A1) and immunological responses (IFI204 and IFIT3).

Discussion: These findings suggested that bicyclol is a potential preventive agent for NAFLD/NASH by targeting multiple mechanisms in future clinical investigations.