Farnesoid X Receptor as Target for Therapies to Treat Cholestasis-Induced Liver Injury

Metabolomics and serum pharmacochemistry combined with network pharmacology uncover the potential effective ingredients and mechanisms of Yin-Chen-Si-Ni Decoction treating ANIT-induced cholestatic liver injury

ETHNOPHARMACOLOGICAL RELEVANCE

Yin-Chen-Si-Ni Decoction is a classical traditional Chinese medicine (TCM) prescription that is used clinically for treating cholestatic liver injury (CLI) and other hepatic diseases. However, the material basis and underlying mechanisms of YCSND are not clear.

AIM OF THE STUDY

To investigate effective components and mechanisms of YCSND in the treatment of CLI using serum pharmacochemistry, metabolomics, and network pharmacology.

MATERIALS AND METHODS

Biochemical indicators, liver index, and histopathology analysis were adopted to evaluate the protective effect of YCSND on ANIT-induced CLI rats. Then, a UPLC-Q-Exactive Orbitrap MS/MS analysis of the migrant components in serum and liver including prototype and metabolic components was performed in YCSND. In addition, a study of the endogenous metabolites using serum and liver metabolomics was performed to discover potential biomarkers, metabolic pathways, and associated mechanisms. Further, the network pharmacology oriented by in vivo migrant components was also used to pinpoint the active ingredients, core targets, and signaling pathways of YCSND. Finally, molecular docking and molecular dynamics simulation (MDS) were used to predict the binding ability between components and core targets, and a real-time qPCR (RT-qPCR) experiment was used to measure the mRNA expression of the core target genes.

RESULTS

Pharmacodynamic studies suggest that YCSND could exert obvious hepatoprotective effects on CLI rats. Furthermore, 68 compounds, comprising 32 prototype components and 36 metabolic components from YCSND, were found by serum pharmacochemistry analysis. Network pharmacology combining molecular docking and MDS showed that apigenin, naringenin, 18β-glycyrrhetinic acid, and isoformononetin have better binding ability to 6 core targets (EGFR, AKT1, IL6, MMP9, CASP3, PPARG). Additionally, PI3K, TNF-α, MAPK3, and six core target genes in liver tissues were validated with RT-qPCR. Metabolomics revealed the anti-CLI effects of YCSND by regulating four metabolic pathways of primary bile acid and biosynthesis, phenylalanine, tyrosine and tryptophan biosynthesis, taurine and hypotaurine metabolism, and arachidonic acid metabolism. Integrating metabolomics and network pharmacology identified four pathways related to CLI, including the PI3K-Akt, HIF-1, MAPK, and TNF signaling pathway, which revealed multiple mechanisms of YCSND against CLI that might involve anti-inflammatory and apoptosis.

CONCLUSION

The research based on serum pharmacochemistry, network pharmacology, and metabolomics demonstrates the beneficial hepatoprotective effects of YCSND on CLI rats by regulating multiple components, multiple targets, and multiple pathways, and provides a potent means of illuminating the material basis and mechanisms of TCM prescriptions.

Caffeoylquinic acids from Silphium perfoliatum L. show hepatoprotective effects on cholestatic mice by regulating enterohepatic circulation of bile acids

ETHNOPHARMACOLOGICAL RELEVANCE

The incidence of cholestatic liver disease (CLD), which is primarily marked by abnormal bile acids (BAs) metabolism and can result in significant hepatic injury, is rising. Nevertheless, there remains a lack of effective treatments and drugs in clinical practice. Silphium perfoliatum L. (SP) is rich in various structural types of caffeoylquinic acid (CQA) compounds, and it is a traditional herb of North American Indians with hepatobiliary therapy effects. However, its therapeutic effect and mechanism of action on CLD have never been studied.

AIM OF THE STUDY

To determine if SP-8, an extract rich in CQAs from SP, protects against cholestatic liver injury induced by alpha-naphthylisothiocyanate (ANIT) and to clarify its mechanism based on the farnesoid x receptor (FXR) signaling pathway and enterohepatic circulation of BAs.

MATERIALS AND METHODS

The therapeutic efficacy of SP-8 was evaluated by assessing the serum biochemical indices, inflammatory factors, and liver histopathology. Targeted metabolomics of the BAs was studied in the feces, liver, serum, and bile using UPLC-MS/MS. Additionally, a Western blot analysis was used to examine the expression levels of the peroxisome proliferator-activated receptor γ (PPARγ), the FXR, and proteins related to the synthesis and transport of BAs. 16S rRNA gene sequencing was performed to evaluate the gut microbiota (GM). Finally, molecular docking simulations were conducted to assess the interaction between seven types of CQAs from SP-8 with FXR and PPARγ.

RESULTS

SP-8 significantly enhanced the health status of cholestatic mice induced by ANIT as evidenced by a notable reduction in the liver function indices and pro-inflammatory factors, restoration of liver pathological damage, and acceleration of BAs excretion through the feces. In addition, the levels of harmful secondary BAs in the liver and blood were significantly reduced by SP-8. Furthermore, the results of the study on the mechanism of action confirmed that SP-8 not only regulated FXR and PPARγ but also significantly ameliorated the GM structure, thereby promoting the enterohepatic circulation of BAs and achieving the homeostasis of the BAs in the blood and liver. In addition, SP-8 successfully reduced the inflammatory response by strongly suppressing the nuclear translocation of NF-κBp65. According to the molecular docking results, the extract's primary active ingredients could be the seven CQAs in SP-8, as they exhibited a strong affinity for both FXR and PPARγ. Finally, the Mantel test analysis revealed a significant correlation among cholestatic-associated parameters, the GM, and BAs.

CONCLUSION

It was confirmed for the first time that the SP-8 extract of Silphium perfoliatum L. that is rich in seven CQAs had a strong therapeutic effect on ANIT-induced CLD. Its mechanism may involve the regulation of the FXR signaling pathway and the amelioration of the GM structure to promote the homeostasis of BAs enterohepatic circulation. This study provides a potential candidate medicinal herb and its components for the development of CLD therapeutic drugs.

Decoding the Role of CYP450 Enzymes in Metabolism and Disease: A Comprehensive Review

Cytochrome P450 (CYP450) is a group of enzymes that play an essential role in Phase I metabolism, with 57 functional genes classified into 18 families in the human genome, of which the CYP1, CYP2, and CYP3 families are prominent. Beyond drug metabolism, CYP enzymes metabolize endogenous compounds such as lipids, proteins, and hormones to maintain physiological homeostasis. Thus, dysregulation of CYP450 enzymes can lead to different endocrine disorders. Moreover, CYP450 enzymes significantly contribute to fatty acid metabolism, cholesterol synthesis, and bile acid biosynthesis, impacting cellular physiology and disease pathogenesis. Their diverse functions emphasize their therapeutic potential in managing hypercholesterolemia and neurodegenerative diseases. Additionally, CYP450 enzymes are implicated in the onset and development of illnesses such as cancer, influencing chemotherapy outcomes. Assessment of CYP450 enzyme expression and activity aids in evaluating liver health state and differentiating between liver diseases, guiding therapeutic decisions, and optimizing drug efficacy. Understanding the roles of CYP450 enzymes and the clinical effect of their genetic polymorphisms is crucial for developing personalized therapeutic strategies and enhancing drug responses in diverse patient populations.

Salvianolic acid extract prevents Tripterygium wilfordii polyglycosides-induced acute liver injury by modulating bile acid metabolism

ETHNOPHARMACOLOGICAL RELEVANCE

Tripterygium wilfordii polyglycosides (TWP) tablet is the most widely used traditional Chinese medicine preparation for the treatment of rheumatoid arthritis (RA), but the hepatotoxicity often limits its widespread application. In traditional use, Salvia miltiorrhiza has cardioprotective and hepatoprotective effects. Salvianolic acid extract (SA) is a hydrophilic component of Salvia miltiorrhiza and has significant antioxidant and hepatoprotective effects.

AIM OF THE STUDY

To investigate the protective effects of SA on the TWP-induced acute liver injury in rats and to explore the related mechanisms by integration of metabolomics and transcriptomics.

MATERIALS AND METHODS

SA and TWP extracts were identified by UPLC-Q/TOF-MS. SA (200 mg/kg) was administered for consecutive 7 days. On day 7, TWP (360 mg/kg) was administered by gavage to induce the acute liver injury in rats. Serum biochemical assay and H&E staining were used to evaluate liver damage. Liver metabolomics and transcriptomics were used to explore the potential mechanisms, and further molecular biological experiments such as qPCR and IHC were utilized to validate the relevant signaling pathways.

RESULTS

SA can prevent liver injury symptoms caused by TWP, such as elevated liver index, elevated ALT and AST, and pathological changes in liver tissue. Liver metabolomics studies showed that TWP can significantly alter the content of individual bile acid in the liver and SA had the most significant impact on the biosynthetic pathway of bile acids. The transcriptomics results of the liver indicated that the genes changed in the SA + TWP group were mainly involved in sterol metabolism, lipid regulation and bile acid homeostasis pathways. The gene expression of Nr1h4, which encodes farnesoid X receptor (FXR), an important regulator of bile acid homeostasis, was significantly changed. Further studies confirmed that SA can prevent the downregulation of FXR and its downstream signaling induced by TWP, thereby regulating bile acid metabolism, ultimately preventing acute liver injury caused by TWP.

CONCLUSION

Our results demonstrated that SA could protect the liver from TWP-induced hepatic injury by modulation of the bile acid metabolic pathway. SA may provide a new strategy for the protection against TWP-induced acute liver injury.

Extract of Silphium perfoliatum L. improve lipid accumulation in NAFLD mice by regulating AMPK/FXR signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Globally, the incidence rate and number of patients with nonalcoholic fatty liver disease are increasing, which has become one of the greatest threats to human health. However, there is still no effective therapy and medicine so far. Silphium perfoliatum L. is a perennial herb native to North America, which is used to improve physical fitness and treat liver and spleen related diseases in the traditional medicinal herbs of Indian tribes. This herb is rich in chlorogenic acids, which have the functions of reducing blood lipids, losing weight and protecting liver. However, the effect of these compounds on nonalcoholic fatty liver disease remains unclear.

AIM OF THE STUDY

Clarify the therapeutic effects and mechanism of the extract (CY-10) rich in chlorogenic acid and its analogues from Silphium perfoliatum L. on non-alcoholic fatty liver disease, and to determine the active compounds.

MATERIALS AND METHODS

A free fatty acid-induced steatosis model of HepG2 cells was established to evaluate the in vitro activity of CY-10 in promoting lipid metabolism. Further, a high-fat diet-induced NAFLD model in C57BL/6 mice was established to detect the effects of CY-10 on various physiological and biochemical indexes in mice, and to elucidate the in vivo effects of the extract on regulating lipid metabolism, anti-inflammation and hepatoprotection, and nontarget lipid metabolomics was performed to analyze differential metabolites of fatty acids in the liver. Subsequently, western blotting and immunohistochemistry were used to analyze the target of the extract and elucidate its mechanism of action. Finally, the active compounds in CY-10 were elucidated through in vitro activity screening.

RESULTS

The results indicated that CY-10 significantly attenuated lipid droplet deposition in HepG2 cells. The results of in vivo experiments showed that CY-10 significantly reduce HFD-induced mouse body weight and organ index, improve biochemical indexes, oxidation levels and inflammatory responses in the liver and serum, thereby protecting the liver tissue. It can promote the metabolism of unsaturated fatty acids in the liver and reduce the generation of saturated fatty acids. Furthermore, it is clarified that CY-10 can promote lipid metabolism balance by regulating AMPK/FXR/SREPB-1c/PPAR-γ signal pathway. Ultimately, the main active compound was proved to be cryptochlorogenic acid, which has a strong promoting effect on the metabolism of fatty acids in cells. Impressively, the activities of CY-10 and cryptochlorogenic acid were stronger than simvastatin in vitro and in vivo.

CONCLUSION

For the first time, it is clarified that the extract rich in chlorogenic acids and its analogues in Silphium perfoliatum L. have good therapeutic effects on non-alcoholic fatty liver disease. It is confirmed that cryptochlorogenic acid is the main active compound and has good potential for medicine.

Molecular insights into experimental models and therapeutics for cholestasis

Cholestatic liver disease (CLD) is a range of conditions caused by the accumulation of bile acids (BAs) or disruptions in bile flow, which can harm the liver and bile ducts. To investigate its pathogenesis and treatment, it is essential to establish and assess experimental models of cholestasis, which have significant clinical value. However, owing to the complex pathogenesis of cholestasis, a single modelling method can merely reflect one or a few pathological mechanisms, and each method has its adaptability and limitations. We summarize the existing experimental models of cholestasis, including animal models, gene-knockout models, cell models, and organoid models. We also describe the main types of cholestatic disease simulated clinically. This review provides an overview of targeted therapy used for treating cholestasis based on the current research status of cholestasis models. In addition, we discuss the respective advantages and disadvantages of different models of cholestasis to help establish experimental models that resemble clinical disease conditions. In sum, this review not only outlines the current research with cholestasis models but also projects prospects for clinical treatment, thereby bridging basic research and practical therapeutic applications.

Vitamin D Receptor Activation Reduces Hepatic Inflammation via Enhancing Macrophage Autophagy in Cholestatic Mice

Macrophage autophagy dysfunction aggravates liver injury by activating inflammasomes, which can cleave pro-IL-1β to its active, secreted form. We investigated whether the vitamin D/vitamin D receptor (VDR) axis could up-regulate macrophage autophagy function to inhibit the activation of inflammasome-dependent IL-1β during cholestasis. Paricalcitol (PAL; VDR agonist) was intraperitoneally injected into bile duct-ligated mice for 5 days. Up-regulation of VDR expression by PAL reduced liver injury by reducing the oxidative stress-induced inflammatory reaction in macrophages. Moreover, PAL inhibited inflammasome-dependent IL-1β generation. Mechanistically, the knockdown of VDR increased IL-1β generation, whereas VDR overexpression exerted the opposite effect following tert-butyl hydroperoxide treatment. The inflammasome antagonist glyburide, the caspase-1-specific inhibitor YVAD, and the reactive oxygen species (ROS) scavenger N-acetyl-l-cysteine (NAC) blocked the increase in Vdr shRNA-induced IL-1β production. Interestingly, up-regulation of VDR also enhanced macrophage autophagy. Autophagy reduction impaired the up-regulation of VDR-inhibited macrophage inflammasome-generated IL-1β, whereas autophagy induction showed a synergistic effect with VDR overexpression through ROS-p38 mitogen-activated protein kinase (MAPK) pathway. This result was confirmed by p38 MAPK inhibitor, MAPK activator, and ROS inhibitor NAC. Collectively, PAL triggered macrophage autophagy by suppressing activation of the ROS-p38 MAPK pathway, which, in turn, suppressed inflammasome-generated cleaved, active forms of IL-1β, eventually leading to reduced inflammation. Thus, triggering the VDR may be a potential target for the anti-inflammatory treatment of cholestatic liver disease.

Papaverine attenuates the progression of alpha naphthylisothiocyanate induce cholestasis in rats

Cholestasis is a hepatobiliary condition that manifests as acute or chronic and results from disruptions in the bile flow, formation, or secretion processes. The Farnesoid X receptor (FXR) is a vital target for the therapy of cholestasis since it regulates BA homeostasis. Despite the discovery of multiple active FXR agonists, there are still no effective treatments for cholestasis. Papaverine is identified as an FXR agonist.This study investigates papaverine's efficacy and probable mechanism in protecting against alpha naphthylisothiocyanate (ANIT) induced cholestasis. Thirty male albino rats were divided into three groups, each with ten rats. Group I (control) rats were administered 1 mL/kg corn oil 48 h before sacrifice; group II rats were orally administered 100 mg/kg ANIT. Group III received a 200 mg/kg dosage of papaverine over seven consecutive days. A single dose of ANIT at a concentration of 100 mg/kg was orally administered on the fifth day; group II and III animals were euthanized 48 h after inducing cholestasis, and serum concentrations of liver function tests and total bile acid (TBA) were measured. Besides measuring the inflammatory mediator's tumor necrosis factor-alpha (TNF-α) and interleukin 1 (IL-1β), antioxidant markers such as superoxide dismutase (SOD) and glutathione (GSH) were also assessed. The findings indicated the enhancement in the liver function test and total bile acids, as well as in liver histology; papaverine significantly lowered TNF-α and IL-1β while SOD and GSH significantly increased. Additionally, papaverine upregulates Fxr gene expression, bile salt export pump (Besp), small heterodimer partner (shp), hepatocyte nuclear factor 1α (Hnfα), nuclear factor erythroid 2-related factor (Nrf2), heme oxygenase (Ho-1), NAD(P)H quinone oxidoreductase 1 (Nqo1). Furthermore, papaverine increased protein expressions of Sirtuin1. (SIRT 1), FXR, HO-1, and BSEP levels in the rats' livers. The protective effects of papaverine may be attributed to the activation of FXR signaling pathways. These findings revealed that papaverine protects against ANIT-induced Cholestasis.

Astragalus saponins protect against extrahepatic and intrahepatic cholestatic liver fibrosis models by activation of farnesoid X receptor

ETHNOPHARMACOLOGICAL RELEVANCE

Cholestatic Liver Fibrosis (CLF) is a hepatobiliary disease that typically arises as a late-stage complication of cholestasis, which can have multiple underlying causes. There are no satisfactory chemical or biological drugs for CLF. Total Astragalus saponins (TAS) are considered to be the main active constituents of the traditional Chinese herb Astragali Radix (AR), which has the obvious improvement effects for treating CLF. However, the mechanism of anti-CLF effects of TAS is still unclear.

AIM OF THE STUDY

The present study was undertaken to investigate the therapeutic effects of TAS against bile duct ligation (BDL) and 3, 5-diethoxycarbonyl-1,4-dihydroxychollidine (DDC) -induced CLF models and to reveal the potential mechanism to support its clinic use with scientific evidence.

MATERIALS AND METHODS

In this study, BDL-induced CLF rats were treated with TAS (20 mg/kg, 40 mg/kg) and DDC-induced CLF mice were treated with 56 mg/kg TAS. The therapeutic effects of TAS on extrahepatic and intrahepatic CLF models were evaluated by serum biochemical analysis, liver histopathology and hydroxyproline (Hyp). Thirty-nine individual bile acids (BAs) in serum and liver were quantified by using UHPLC-Q-Exactive Orbitrap HRMS. qRT-PCR, Western blot and immunohistochemistry analysis were used to measure the expression of liver fibrosis and ductular reaction markers, inflammatory factors and BAs related metabolic transporters, along with nuclear receptor farnesoid X receptor (FXR).

RESULTS

The serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), total bilirubin (TBiL), direct bilirubin (DBiL) and contents of liver Hyp were dose-dependently improved after treatment for TAS in BDL and DDC- induced CLF models. And the increased levels of ALT and AST were significantly improved by total extract from Astragali radix (ASE) in BDL model. The liver fibrosis and ductular reaction markers, α-smooth muscle actin (α-SMA) and cytokeratin 19 (CK19), were significantly ameliorated in TAS group. And the liver expression of inflammatory factors: interleukin 6 (IL-6), tumor necrosis factor-α (TNF-α) and interleukin 1β (IL-1β) were significantly decreased after TAS treatment. In addition, TAS significantly ameliorated taurine-conjugated BAs (tau-BAs) levels, particularly α-TMCA, β-TMCA and TCA contents in serum and liver, which correlated with induced expressions of hepatic FXR and BAs secretion transporters. Furthermore, TAS significantly improved short heterodimer partner (SHP), cholesterol 7α-hydroxylase (Cyp7a1), Na+ taurocholate cotransport peptide (NTCP) and bile-salt export pump (BSEP) mRNA and protein expression.

CONCLUSIONS

TAS exerted a hepatoprotective effect against CLF by ameliorating liver injury, inflammation and restoring the altered tau-BAs metabolism to produce a positive regulatory effect on FXR-related receptors and transporters.

Akkermansia muciniphila might improve anti-PD-1 therapy against HCC by changing host bile acid metabolism

PD-1 monoclonal antibodies (mAb) have demonstrated remarkable efficacy in a variety of cancers, including Hepatocellular carcinoma (HCC). However, the patient response rates remain suboptimal, and a significant proportion of initial responders may develop resistance to this therapeutic approach. Akkermansia muciniphila (AKK), a microorganism implicated in multiple human diseases, has been reported to be more abundant in patients who exhibit favorable responses to PD-1mAb. However, the underlying mechanism has yet to be elucidated. In our study, we found that AKK could enhance the efficacy of PD-1mAb against HCC in a tumor-bearing mouse model. It promotes HCC tumor cells apoptosis and raise the CD8+ T proportion in the tumor microenvironment. Additionally, AKK downregulates PD-L1 expression in tumor cells. Furthermore, the analysis of metabonomics demonstrates that AKK induces alterations in the host's bile acid metabolism, leading to a significant increase in serum TUDCA levels. Considering the immunosuppresive roles of TUDCA in HCC development, it is plausible to speculate that AKK may reinforce the immunotherapy of PD-1mAb against HCC through its impact on bile acid metabolism.

Human Hepatocellular response in Cholestatic Liver Diseases

Primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC), the most common types of cholestatic liver disease (CLD), result in enterohepatic obstruction, bile acid accumulation, and hepatotoxicity. The mechanisms by which hepatocytes respond to and cope with CLD remain largely unexplored. This study includes the characterization of hepatocytes isolated from explanted livers of patients with PBC and PSC. We examined the expression of hepatocyte-specific genes, intracellular bile acid (BA) levels, and oxidative stress in primary-human-hepatocytes (PHHs) isolated from explanted livers of patients with PBC and PSC and compared them with control normal human hepatocytes. Our findings provide valuable initial insights into the hepatocellular response to cholestasis in CLD and help support the use of PHHs as an experimental tool for these diseases.

The contributions of bacteria metabolites to the development of hepatic encephalopathy

Over 20% of mortality during acute liver failure is associated with the development of hepatic encephalopathy (HE). Thus, HE is a complication of acute liver failure with a broad spectrum of neuropsychiatric abnormalities ranging from subclinical alterations to coma. HE is caused by the diversion of portal blood into systemic circulation through portosystemic collateral vessels. Thus, the brain is exposed to intestinal-derived toxic substances. Moreover, the strategies to prevent advancement and improve the prognosis of such a liver-brain disease rely on intestinal microbial modulation. This is supported by the findings that antibiotics such as rifaximin and laxative lactulose can alleviate hepatic cirrhosis and/or prevent HE. Together, the significance of the gut-liver-brain axis in human health warrants attention. This review paper focuses on the roles of bacteria metabolites, mainly ammonia and bile acids (BAs) as well as BA receptors in HE. The literature search conducted for this review included searches for phrases such as BA receptors, BAs, ammonia, farnesoid X receptor (FXR), G protein-coupled bile acid receptor 1 (GPBAR1 or TGR5), sphingosine-1-phosphate receptor 2 (S1PR2), and cirrhosis in conjunction with the phrase hepatic encephalopathy and portosystemic encephalopathy. PubMed, as well as Google Scholar, was the search engines used to find relevant publications.

Characteristics and metabolic potential of biliary microbiota in patients with giant common bile duct stones

Background

Endoscopic retrograde cholangiopancreatography (ERCP) is an effective minimally invasive operation for the management of choledocholithiasis, while successful extraction is hampered by large diameter of stones. Emerging studies have revealed the close correlation between biliary microbiota and common bile duct stones (CBDS). In this study, we aimed to investigate the community characteristics and metabolic functions of biliary microbiota in patients with giant CBDS.

Methods

Eligible patients were prospectively enrolled in this study in First Affiliated Hospital of Soochow University from February 2022 to October 2022. Bile samples were collected through ERCP. The microbiota was analyzed using 16S rRNA sequencing. Metabolic functions were predicted by PICRUSTs 2.0 calculation based on MetaCyc database. Bile acids were tested and identified using ultra performance liquid chromatography-tandem mass spectrometry.

Results

A total of 26 patients were successfully included into final analysis, 8 in giant stone (GS) group and 18 in control group. Distinct biliary microbial composition was identified in patients with giant CBDS, with a significantly higher abundance of Firmicutes at phylum level. The unique composition at genus level mainly consisted of Enterococcus, Citrobacter, Lactobacillus, Pyramidobacter, Bifidobacterium and Shewanella. Pyramidobacter was exclusively found in GS group, along with the absence of Robinsoniella and Coprococcus. The contents of free bile acids were significantly higher in GS group, including cholic acid (98.39μmol/mL vs. 26.15μmol/mL, p=0.035), chenodesoxycholic acid (54.69μmol/mL vs. 5.86μmol/mL, p=0.022) and ursodeoxycholic acid (2.70μmol/mL vs. 0.17μmol/mL, p=0.047). Decreasing tendency of conjugated bile acids were also observed. Metabolic pathways concerning cholelithiasis were abundant in GS group, including geranylgeranyl diphosphate biosynthesis, gluconeogenesis, glycolysis and L-methionine biosynthesis.

Conclusions

This study demonstrated the community structure and metabolic potential of biliary microbiota in patients with giant CBDS. The unique biliary microbial composition holds valuable predictive potential for clinical conditions. These findings provide new insights into the etiology of giant CBDS from the perspective of biliary microbiota.

Current and investigational drugs in early clinical development for portal hypertension

Introduction

The development of portal hypertension leads to a majority of complications associated with chronic liver disease. Therefore, adequate treatment of portal hypertension is crucial in the management of such patients. Current treatment options are limited and consist mainly of medications that decrease the hyperdynamic circulation, such as non-selective beta blockers, and treatment of hypervolemia with diuretics. Despite these options, mortality rates have not improved over the last two decades. Newer, more effective treatment options are necessary to help improve survival and quality of life in these patients.

Areas covered

Multiple preclinical models and clinical studies have demonstrated potential efficacy of a variety of new treatment modalities. We introduce treatment options including the use of vasodilation promotors, vasoconstriction inhibitors, anticoagulants, antiangiogenics, and anti-inflammatory drugs. We examine the most recent studies for treatment options within these drug classes and offer insights as to which show the most promise in this field.

Methodology

Published studies that identified novel medical treatment options of portal hypertension were searched using PubMed (https://pubmed.ncbi.nlm.nih.gov/). Clinical trials listed in Clinicaltrials.gov were also searched with a focus on more recent and ongoing studies, including those with completed recruitment. Searching with key terms including "portal hypertension" as well as individually searching specific treatment medications that were listed in other publications was carried out. Finally, current societal guidelines and recent review articles relevant to the management of portal hypertension were evaluated, and listed references of interest were included.

Conclusion

Many ongoing early phase studies demonstrate promising results and may shape the field of portal hypertension management in future. As concrete results become available, larger RCTs will be required before making definitive conclusions regarding safety and efficacy and whether or not they can be incorporated into routine clinical practice. Statins, anticoagulants, and PDE inhibitors have been among the most studied and appear to be most promising.

Long-term oral administration of Epimedii Folium induced cholestasis in mice by interfering with bile acid transport

ETHNOPHARMACOLOGICAL RELEVANCE

Epimedii Folium (EF) is a common traditional Chinese medicine that functions as a tonifying kidney yang to strengthen bones and muscles and dispel wind dampness (limb pain, lethargy, nausea, anorexia, and loose stools). Several studies have reported the potential risk of cholestatic liver damage from EF use; however, there have been few investigations of EF-induced cholestasis, particularly the underlying mechanisms.

AIMS OF THE STUDY

The purpose of this study was to evaluate the risk of EF-induced cholestasis in vivo and to explore the mechanisms of action.

MATERIALS AND METHODS

ICR mice were orally administered a water extract of EF (WEF) in doses of 6.5 and 19.5 g/kg/day for 14 weeks. Liver-to-body weight ratios, body weight, histopathological examination, and biochemical analyses were performed to assess WEF-induced cholestasis in the mice. Genes associated with bile acid (BA) metabolism and transport, including sodium taurocholate cotransporting polypeptide (NTCP), cytochrome P450 8B1 (CYP8B1), bile-salt export pump (BSEP), multidrug resistance P-glycoproteins 1 (MDR1), and farnesoid X receptor (FXR), were measured at the transcript and protein levels to investigate the potential mechanisms through which cholestasis is aroused by EF.

RESULTS

After administration of WEF for 14 weeks, mice in the high-dose WEF group showed poor health with an increased liver-to-body weight ratio as well as higher serum aminotransferase, alkaline phosphatase, direct bilirubin, and total BA levels. Compared with the control group, mRNA expression of NTCP and cholesterol 7a-hydroxylase (CYP7A1) increased, and levels of BSEP, MDR1, multidrug resistance-associated protein 2, and multidrug resistance-associated protein 3 decreased in the WEF-treated group. NTCP, BSEP, MDR1, and CYP8B1 showed similar mRNA and protein expression trends.

CONCLUSION

We demonstrated that the long-term oral administration of WEF causes cholestatic liver injury in mice, which is consistent with reported clinical cases. Furthermore, we found that the destruction of BA metabolism and transport is involved in WEF-induced cholestasis. The fine-scale molecular mechanisms of WEF-induced cholestasis and the active compounds of EF need further study.

The role of the farnesoid X receptor in quadruple anti-tuberculosis drug-induced liver injury

Anti-tuberculosis drugs-induced liver injury may be associated with the hepatic farnesoid X receptor (FXR). However, the relationship between isoniazid, rifampicin, pyrazinamide and ethambutol (HRZE) coadministration-induced liver injury and FXR has not been clarified. The purpose of this study was to clarify the role of FXR in HRZE-induced liver injury. To measure indices of liver injury, blood samples were collected from clinical tuberculosis patients who had taken HRZE for approximately two months; in these patients serum total bile acids were increased, while other hepatic biochemical indexes showed no significant changes. When Wistar rats were orally administered isoniazid (30 or 60 mg/kg) + rifampicin (45 or 90 mg/kg) + pyrazinamide (150 or 300 mg/kg) + ethambutol (75 or 150 mg/kg) in combination for 15 days, the expression and function of FXR was up-regulated, and hepatic bile acids were decreased. However, following 30 days of HRZE treatment the expression and function of FXR was down-regulated and bile acids accumulated in the liver, suggestive of hepatotoxicity. Treatment of HepaRG cells with HRZE lead to time- and dose- dependent cytotoxicity, with the expression of FXR up-regulated in early stage, but down-regulated with prolonged HRZE treatment, consistent with the results of animal experiments. In summary, HRZE may upregulate FXR with short-term administration, but more prolonged treatment appears to suppress FXR function, resulting in hepatic bile acid accumulation.

Recent advances in nuclear receptors-mediated health benefits of blueberry

BACKGROUND

Blueberry is rich in bioactive substances and has anti-oxidant, anti-inflammatory, anti-obesity, anti-cancer, neuroprotective, and other activities. Blueberry has been shown to treat diseases by mediating the transcription of nuclear receptors. However, evidence for nuclear receptor-mediated health benefits of blueberry has not been systematically reviewed.

PURPOSE

This review aims to summarize the nuclear receptor-mediated health benefits of blueberry.

METHODS

This study reviews all relevant literature published in NCBI PubMed, Scopus, Web of Science, and Google Scholar by January 2022. The relevant literature was extracted from the databases with the following keyword combinations: "biological activities" OR "nuclear receptors" OR "phytochemicals" AND "blueberry" OR "Vaccinium corymbosum" as well as free-text words.

RESULTS

In vivo and in vitro experimental results and clinical evidence have demonstrated that blueberry has health-promoting effects. Supplementing blueberry is beneficial to the treatment of cancer, the alleviation of metabolic syndrome, and liver protection. Blueberry can regulate the transcription of PPARs, ERs, AR, GR, MR, LXRs, and FXR and mediate the expressions of Akt, CYP 1Al, p53, and Bcl-2.

CONCLUSION

Blueberry can be targeted to treat various diseases by mediating the transcription of nuclear receptors. Nevertheless, further human research is needed.

Selective PPARδ agonist seladelpar suppresses bile acid synthesis by reducing hepatocyte CYP7A1 via the fibroblast growth factor 21 signaling pathway

Peroxisome proliferator–activated receptor delta (PPARδ) agonists have been shown to exert beneficial effects in liver disease and reduce total bile acid levels. The mechanism(s) whereby PPARδ agonism reduces bile acid levels are, however, unknown, and therefore the aim of the present study was to investigate the molecular pathways responsible for reducing bile acid synthesis in hepatocytes, following treatment with the selective PPARδ agonist, seladelpar. We show that administration of seladelpar to WT mice repressed the liver expression of cholesterol 7 alpha-hydroxylase (Cyp7a1), the rate-limiting enzyme for bile acid synthesis, and decreased plasma 7α-hydroxy-4-cholesten-3-one (C4), a freely diffusible metabolite downstream of Cyp7a1. In primary mouse hepatocytes, seladelpar significantly reduced the expression of Cyp7a1 independent of the nuclear bile acid receptor, Farnesoid X receptor. In addition, seladelpar upregulated fibroblast growth factor 21 (Fgf21) in mouse liver, serum, and in cultured hepatocytes. We demonstrate that recombinant Fgf21 protein activated the c-Jun N-terminal kinase (JNK) signaling pathway and repressed Cyp7a1 gene expression in primary hepatocytes. The suppressive effect of seladelpar on Cyp7a1 expression was blocked by a JNK inhibitor as well as in the absence of Fgf21, indicating that Fgf21 plays an indispensable role in PPARδ-mediated downregulation of Cyp7a1. Finally, reduction of CYP7A1 expression by seladelpar was confirmed in primary human hepatocytes. In conclusion, we show that seladelpar reduces bile acid synthesis via an FGF21-dependent mechanism that signals at least partially through JNK to repress CYP7A1.

Transcriptional Regulation of Hepatic Autophagy by Nuclear Receptors

Autophagy is an adaptive self-eating process involved in degradation of various cellular components such as carbohydrates, lipids, proteins, and organelles. Its activity plays an essential role in tissue homeostasis and systemic metabolism in response to diverse challenges, including nutrient depletion, pathogen invasion, and accumulations of toxic materials. Therefore, autophagy dysfunctions are intimately associated with many human diseases such as cancer, neurodegeneration, obesity, diabetes, infection, and aging. Although its acute post-translational regulation is well described, recent studies have also shown that autophagy can be controlled at the transcriptional and post-transcriptional levels. Nuclear receptors (NRs) are in general ligand-dependent transcription factors consisting of 48 members in humans. These receptors extensively control transcription of a variety of genes involved in development, metabolism, and inflammation. In this review, we discuss the roles and mechanisms of NRs in an aspect of transcriptional regulation of hepatic autophagy, and how the NR-driven autophagy pathway can be harnessed to treat various liver diseases.

Bile Acids Activate NLRP3 Inflammasome, Promoting Murine Liver Inflammation or Fibrosis in a Cell Type-Specific Manner

Bile acids (BA) as important signaling molecules are considered crucial in development of cholestatic liver injury, but there is limited understanding on the involved cell types and signaling pathways. The aim of this study was to evaluate the inflammatory and fibrotic potential of key BA and the role of distinct liver cell subsets focusing on the NLRP3 inflammasome. C57BL/6 wild-type (WT) and Nlrp3^−/− mice were fed with a diet supplemented with cholic (CA), deoxycholic (DCA) or lithocholic acid (LCA) for 7 days. Additionally, primary hepatocytes, Kupffer cells (KC) and hepatic stellate cells (HSC) from WT and Nlrp3^−/− mice were stimulated with aforementioned BA ex vivo. LCA feeding led to strong liver damage and activation of NLRP3 inflammasome. Ex vivo KC were the most affected cells by LCA, resulting in a pro-inflammatory phenotype. Liver damage and primary KC activation was both ameliorated in Nlrp3-deficient mice or cells. DCA feeding induced fibrotic alterations. Primary HSC upregulated the NLRP3 inflammasome and early fibrotic markers when stimulated with DCA, but not LCA. Pro-fibrogenic signals in liver and primary HSC were attenuated in Nlrp3^−/− mice or cells. The data shows that distinct BA induce NLRP3 inflammasome activation in HSC or KC, promoting fibrosis or inflammation.