FXR agonist obeticholic acid induces liver growth but exacerbates biliary injury in rats with obstructive cholestasis

The reversal of PXR or PPARα activation-induced hepatomegaly

The activation of pregnane X receptor (PXR) or peroxisome proliferator-activated receptor α (PPARα) can induce liver enlargement. Recently, we reported that PXR or PPARα activation-induced hepatomegaly depends on yes-associated protein (YAP) signaling and is characterized by hepatocyte hypertrophy around the central vein area and hepatocyte proliferation around the portal vein area. However, it remains unclear whether PXR or PPARα activation-induced hepatomegaly can be reversed after the withdrawal of their agonists. In this study, we investigated the regression of enlarged liver to normal size following the withdrawal of PCN or WY-14643 (typical agonists of mouse PXR or PPARα) in C57BL/6 mice. The immunohistochemistry analysis of CTNNB1 and KI67 showed a reversal of hepatocyte size and a decrease in hepatocyte proliferation after the withdrawal of agonists. In details, the expression of PXR or PPARα downstream proteins (CYP3A11, CYP2B10, ACOX1, and CYP4A) and the expression of proliferation-related proteins (CCNA1, CCND1, and PCNA) returned to the normal levels. Furthermore, YAP and its downstream proteins (CTGF, CYR61, and ANKRD1) also restored to the normal states, which was consistent with the change in liver size. These findings demonstrate the reversibility of PXR or PPARα activation-induced hepatomegaly and provide new data for the safety of PXR and PPARα as drug targets.

Molecular Pathways Governing the Termination of Liver Regeneration

The liver has the unique capacity to regenerate, and up to 70% of the liver can be removed without detrimental consequences to the organism. Liver regeneration is a complex process involving multiple signaling networks and organs. Liver regeneration proceeds through three phases: the initiation phase, the growth phase, and the termination phase. Termination of liver regeneration occurs when the liver reaches a liver-to-body weight that is required for homeostasis, the so-called "hepatostat." The initiation and growth phases have been the subject of many studies. The molecular pathways that govern the termination phase, however, remain to be fully elucidated. This review summarizes the pathways and molecules that signal the cessation of liver regrowth after partial hepatectomy and answers the question, "What factors drive the hepatostat?" SIGNIFICANCE STATEMENT: Unraveling the pathways underlying the cessation of liver regeneration enables the identification of druggable targets that will allow us to gain pharmacological control over liver regeneration. For these purposes, it would be useful to understand why the regenerative capacity of the liver is hampered under certain pathological circumstances so as to artificially modulate the regenerative processes (e.g., by blocking the cessation pathways) to improve clinical outcomes and safeguard the patient's life.

Novel preclinical developments of the primary sclerosing cholangitis treatment landscape

INTRODUCTION

Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease associated with inflammation, fibrosis, and destruction of intra- and extrahepatic bile ducts. Despite substantial recent advances in our understanding of PSC, the only proven treatment of PSC is liver transplantation. There is an urgent unmet need to find medical therapies for this disorder.

AREAS COVERED

Multiple drugs are currently under evaluation as therapeutic options for this disease. This article summarizes the literature on the various novel therapeutic options that have been investigated and are currently under development for the treatment of PSC.

EXPERT OPINION

In the next decade, more than one drug will likely be approved for the treatment of the disease, and we will be looking at combination therapies for the optimal management of the disease.

Inhibiting Wnt Signaling Reduces Cholestatic Injury by Disrupting the Inflammatory Axis

BACKGROUND & AIMS

β-Catenin, the effector molecule of the Wnt signaling pathway, has been shown to play a crucial role in bile acid homeostasis through direct inhibition of farnesoid X receptor (FXR), which has pleiotropic effects on bile acid homeostasis. We hypothesize that simultaneous suppression of β-catenin signaling and activation of FXR in a mouse model of cholestasis will reduce injury and biliary fibrosis through inhibition of bile acid synthesis.

METHODS

To induce cholestasis, we performed bile duct ligation (BDL) on wild-type male mice. Eight hours after surgery, mice received FXR agonists obeticholic acid, tropifexor, or GW-4064 or Wnt inhibitor Wnt-C59. Severity of cholestatic liver disease and expression of target genes were evaluated after either 5 days or 12 days of treatment.

RESULTS

We found that although the FXR agonists worsened BDL-induced injury and necrosis after 5 days, Wnt-C59 did not. After 12 days of BDL, Wnt-C59 treatment, but not GW-4064 treatment, reduced both the number of infarcts and the number of inflammatory cells in liver. RNA sequencing analysis of whole livers revealed a notable suppression of nuclear factor kappa B signaling when Wnt signaling is inhibited. We then analyzed transcriptomic data to identify a cholangiocyte-specific signature in our model and demonstrated that Wnt-C59-treated livers were enriched for genes expressed in quiescent cholangiocytes, whereas genes expressed in activated cholangiocytes were enriched in BDL alone. A similar decrease in biliary injury and inflammation occurred in Mdr2 KO mice treated with Wnt-C59.

CONCLUSIONS

Inhibiting Wnt signaling suppresses cholangiocyte activation and disrupts the nuclear factor kappa B-dependent inflammatory axis, reducing cholestatic-induced injury.

Recent evaluation about inflammatory mechanisms in nonalcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is common chronic metabolic liver disorder which is associated with fat accumulation in the liver. It causes a wide range of pathological effects such as insulin resistance, obesity, hypertension, diabetes, non-alcoholic steatohepatitis (NASH) and cirrhosis, cardiovascular diseases. The molecular mechanisms that cause the initiation and progression of NAFLD remain fully unclear. Inflammation is regarded as a significant mechanism which could result in cell death and tissue injury. Accumulation of leukocytes and hepatic inflammation are important contributors in NAFLD. Excessive inflammatory response can deteriorate the tissue injury in NAFLD. Thus, inhibition of inflammation improves NAFLD by reducing intrahepatic fat content, increasing β-oxidation of fatty acids, inducing hepato-protective autophagy, overexpressing peroxisome proliferator-activated receptor- γ (PPAR-γ), as well as attenuating hepatocyte apoptosis and increasing insulin sensitivity. Therefore, understanding the molecules and signaling pathways suggests us valuable information about NAFLD progression. This review aimed to evaluate the inflammation in NAFLD and the molecular mechanism on NAFLD.

Influence of cholestasis on portal vein embolization-induced hypertrophy of the future liver remnant

PURPOSE

In the pre-clinical setting, hepatocellular bile salt accumulation impairs liver regeneration following partial hepatectomy. Here, we study the impact of cholestasis on portal vein embolization (PVE)-induced hypertrophy of the future liver remnant (FLR).

METHODS

Patients were enrolled with perihilar cholangiocarcinoma (pCCA) or colorectal liver metastases (CRLM) undergoing PVE before a (extended) right hemihepatectomy. Volume of segments II/III was considered FLR and assessed on pre-embolization and post-embolization CT scans. The degree of hypertrophy (DH, percentual increase) and kinetic growth rate (KGR, percentage/week) were used to assess PVE-induced hypertrophy.

RESULTS

A total of 50 patients (31 CRLM, 19 pCCA) were included. After PVE, the DH and KGR were similar in patients with CRLM and pCCA (5.2 [3.3-6.9] versus 5.7 [3.2-7.4] %, respectively, p = 0.960 for DH; 1.4 [0.9-2.5] versus 1.9 [1.0-2.4] %/week, respectively, p = 0.742 for KGR). Moreover, pCCA patients with or without hyperbilirubinemia had comparable DH (5.6 [3.0-7.5] versus 5.7 [2.4-7.0] %, respectively, p = 0.806) and KGR (1.7 [1.0-2.4] versus 1.9 [0.8-2.4] %/week, respectively, p = 1.000). For patients with pCCA, unilateral drainage in FLR induced a higher DH than bilateral drainage (6.7 [4.9-7.9] versus 2.7 [1.5-4.2] %, p = 0.012). C-reactive protein before PVE was negatively correlated with DH (ρ = - 0.539, p = 0.038) and KGR (ρ = - 0.532, p = 0.041) in patients with pCCA.

CONCLUSIONS

There was no influence of cholestasis on FLR hypertrophy in patients undergoing PVE. Bilateral drainage and inflammation appeared to be negatively associated with FLR hypertrophy. Further prospective studies with larger and more homogenous patient cohorts are desirable.

Microbiota-induced lipid peroxidation impairs obeticholic acid-mediated antifibrotic effect towards nonalcoholic steatohepatitis in mice

Obeticholic acid (OCA) has been examined to treat non-alcoholic steatohepatitis (NASH), but has unsatisfactory antifibrotic effect and deficient responsive rate in recent phase III clinical trial. Using a prolonged western diet-feeding murine NASH model, we show that OCA-shaped gut microbiota induces lipid peroxidation and impairs its anti-fibrotic effect. Mechanically, Bacteroides enriched by OCA deconjugates tauro-conjugated bile acids to generate excessive chenodeoxycholic acid (CDCA), resulting in liver ROS accumulation. We further elucidate that OCA reduces triglycerides containing polyunsaturated fatty acid (PUFA-TGs) levels, whereas elevates free PUFAs and phosphatidylethanolamines containing PUFA (PUFA-PEs), which are susceptible to be oxidized to lipid peroxides (notably arachidonic acid (ARA)-derived 12-HHTrE), inducing hepatocyte ferroptosis and activating hepatic stellate cells (HSCs). Inhibiting lipid peroxidation with pentoxifylline (PTX) rescues anti-fibrotic effect of OCA, suggesting combination of OCA and lipid peroxidation inhibitor could be a potential antifibrotic pharmacological approach in clinical NASH-fibrosis.

Paeoniflorin alleviates 17α-ethinylestradiol-induced cholestasis via the farnesoid X receptor-mediated bile acid homeostasis signaling pathway in rats

Cholestasis, characterized by disturbance of bile formation, is a common pathological condition that can induce several serious liver diseases. As a kind of trigger, estrogen-induced cholestasis belongs to drug-induced cholestasis. Paeoniflorin is the most abundant bioactive constituent in Paeonia lactiflora Pall., Paeonia suffruticosa Andr., or Paeonia veitchii Lynch, a widely used herbal medicine for treating hepatic disease over centuries in China. However, the pharmacologic effect and mechanism of paeoniflorin on estrogen-induced cholestasis remain unclear. In this experiment, the pharmacological effect of paeoniflorin on EE-induced cholestasis in rats was evaluated comprehensively for the first time. Ultra-high-performance liquid chromatography coupled with Q-Exactive orbitrap mass spectrometer was used to monitor the variation of bile acid levels and composition. It was demonstrated that paeoniflorin alleviated 17α-ethinylestradiol (EE)-induced cholestasis dose-dependently, characterized by a decrease of serum biochemical indexes, recovery of bile flow, amelioration of hepatic and ileal histopathology, and reduction of oxidative stress. In addition, paeoniflorin intervention restored EE-disrupted bile acid homeostasis in enterohepatic circulation. Further mechanism studies using western blot, quantitative Real-Time PCR, and immunohistochemical showed that paeoniflorin could upregulate hepatic efflux transporters expression but downregulate hepatic uptake transporter expression. Meanwhile, paeoniflorin reduced bile acids synthesis by repressing cholesterol 7α-hydroxylase in hepatocytes. Paeoniflorin affected the above transporters and enzyme via activation of a nuclear receptor, farnesoid X receptor (FXR), which was recognized as a vital regulator for maintaining bile acid homeostasis. In conclusion, paeoniflorin alleviated EE-induced cholestasis and maintained bile acid homeostasis via FXR-mediated regulation of bile acids transporters and synthesis enzyme. The findings indicated that paeoniflorin might exert a potential therapeutic medicine for estrogen-induced cholestasis.

Predictors of serious adverse events and non-response in cirrhotic patients with primary biliary cholangitis treated with obeticholic acid

BACKGROUND & AIMS

Obeticholic acid (OCA) has recently been restricted in patients with primary biliary cholangitis (PBC) with "advanced cirrhosis" because of its narrow therapeutic index. We aimed to better define the predicting factors of hepatic serious adverse events (SAEs) and non-response in cirrhotic patients undergoing OCA therapy.

METHODS

Safety and efficacy of treatment were evaluated in a cohort of consecutive PBC cirrhotic patients started with OCA. OCA response was evaluated according to the Poise criteria. Risk factors for hepatic SAEs and non-response were reported as risk ratios (RR) with 95% confidence intervals (CIs).

RESULTS

One hundred PBC cirrhotics were included, 97 Child-Pugh class A and 3 class B. Thirty-one had oesophageal varices and 5 had a history of ascites. Thirty-three per cent and 32% of patients achieved a biochemical response at 6 and 12 months respectively. Male sex (adjusted-RR 1.75, 95%CI 1.42-2.12), INR (1.37, 1.00-1.87), Child-Pugh score (1.79, 1.28-2.50), MELD (1.17, 1.04-1.30) and bilirubin (1.83, 1.11-3.01) were independently associated with non-response to OCA. Twenty-two patients discontinued OCA within 12 months: 10 for pruritus, 9 for hepatic SAEs (5 for jaundice and/or ascitic decompensation; 4 for upper digestive bleeding). INR (adjusted-RR 1.91, 95%CI 1.10-3.36), lower albumin levels (0.18, 0.06-0.51), Child-Pugh score (2.43, 1.50-4.04), history of ascites (3.5, 1.85-6.5) and bilirubin (1.30, 1.05-1.56), were associated with hepatic SAEs. A total bilirubin≥1.4 mg/dl at baseline was the most accurate biochemical predictor of hepatic SAEs under OCA.

CONCLUSIONS

An accurate baseline assessment is crucial to select cirrhotic patients who can benefit from OCA. Although OCA is effective in one third of cirrhotics, bilirubin level ≥1.4 mg/dl should discourage from its use.

Bile acids and their receptors: modulators and therapeutic targets in liver inflammation

Bile acids participate in the intestinal emulsion, digestion, and absorption of lipids and fat-soluble vitamins. When present in high concentrations, as in cholestatic liver diseases, bile acids can damage cells and cause inflammation. After the discovery of bile acids receptors about two decades ago, bile acids are considered signaling molecules. Besides regulating bile acid, xenobiotic, and nutrient metabolism, bile acids and their receptors have shown immunomodulatory properties and have been proposed as therapeutic targets for inflammatory diseases of the liver. This review focuses on bile acid-related signaling pathways that affect inflammation in the liver and provides an overview of the preclinical and clinical applications of modulators of these pathways for the treatment of cholestatic and autoimmune liver diseases.

Farnesoid X receptor (FXR) agonists induce hepatocellular apoptosis and impair hepatic functions via FXR/SHP pathway

Farnesoid X receptor (FXR) plays an indispensable role in liver homeostasis and has been a promising drug target for hepatic diseases. However, the concerns of undesired biological actions limit the clinical applications of FXR agonists. To reveal the intrinsic mechanism of FXR agonist-induce hepatotoxicity, two typical FXR agonists with different structures (obeticholic acid (OCA) and Px-102) were investigated in the present study. By detecting MMP, ROS, and ATP and analyzing the fate of cells, we found that both OCA and Px-102 reduced the mitochondrial function of hepatocytes and promoted cell apoptosis. Gene ablation or inhibition of FXR or SHP ameliorated the cytotoxicities of OCA and Px-102, which indicated the adverse actions of FXR/SHP activation including down-regulation of phosphorylation of PI3K/AKT and functional hepatic genes. The dose-related injurious effects of OCA (10 mg/kg and 30 mg/kg) and Px-102 (5 mg/kg and 15 mg/kg) on the liver were confirmed on a high-fat diet mouse model. The decrease of hepatocyte-specific genes and augmenter of liver regeneration in the liver caused by OCA or Px-102 suggested an imbalance of liver regeneration and a disruption of hepatic functions. Exploration of intestinally biased FXR agonists or combination of FXR agonist with apoptosis inhibitor may be more beneficial strategies for liver diseases.

Fibroblast Growth Factor 19 Induced Changes in Non-malignant Cholangiocytes

BACKGROUND AND AIMS

Fibroblast growth factor (FGF)19 has been implicated in the pathogenesis of murine hepatocellular carcinoma. Whether it plays a role in the development or course of human cholangiocarcinoma remains to be determined. The aim of this study was to determine whether prolonged exposure to FGF19 results in the transformation of non-malignant human cholangiocytes into cells with malignant features.

METHODS

Human SV-40 transfected non-malignant H69 cholangiocytes were cultured with FGF19 (0-50 ng/mL) for 6 weeks, followed by 6 weeks with medium alone. Cell proliferation, invasion, stem cell surface markers, oncofetoprotein expression, state of differentiation, epithelial-mesenchymal transition (EMT) and interleukin (IL)-6 expression were documented at various time intervals throughout the 12-week period.

RESULTS

FGF19 exposure was associated with significant increases in cell proliferation, de-differentiation, EMT and IL-6 expression. However, each of these effects returned to baseline or control values during the 6-week FGF19 free follow-up period. The remaining cell properties remained unaltered.

CONCLUSIONS

Six weeks of FGF19 exposure did not result in the acquisition of permanent malignant features in non-malignant, human cholangiocytes.

The Role of Farnesoid X Receptor in Accelerated Liver Regeneration in Rats Subjected to ALPPS

Background: the role of bile acid (BA)-induced farnesoid X receptor (Fxr) signaling in liver regeneration following associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) was investigated in a rat model. Methods: Male Wistar rats underwent portal vein ligation (PVL) (n = 30) or ALPPS (n = 30). Animals were sacrificed pre-operatively and at 24, 48, 72, or 168 h after intervention. Regeneration rate, Ki67 index, hemodynamic changes in the hepatic circulation, and BA levels were assessed. Transcriptome analysis of molecular regulators involved in the Fxr signaling pathway, BA transport, and BA production was performed. Results: ALLPS induced more extensive liver regeneration (p < 0.001) and elevation of systemic and portal BA levels (p < 0.05) than PVL. The mRNA levels of proteins participating in hepatic Fxr signaling were comparable between the intervention groups. More profound activation of the intestinal Fxr pathway was observed 24 h after ALPPS compared to PVL. Conclusion: Our study elaborates on a possible linkage between BA-induced Fxr signaling and accelerated liver regeneration induced by ALPPS in rats. ALPPS could trigger liver regeneration via intestinal Fxr signaling cascades instead of hepatic Fxr signaling, thereby deviating from the mechanism of BA-mediated regeneration following one-stage hepatectomy.

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

Recent studies on liver disease burden worldwide estimated that cirrhosis is the 11th most common cause of death globally, and there is a great need for new therapies to limit the progression of liver injuries in the early stages. Cholestasis is caused by accumulation of hydrophobic bile acids (BA) in the liver due to dysfunctional BA efflux or bile flow into the gall bladder. Therefore, strategies to increase detoxification of hydrophobic BA and downregulate genes involved in BA production are largely investigated. Farnesoid X receptor (FXR) has a central role in BA homeostasis and recent publications revealed that changes in autophagy due to BA-induced reactive oxygen species and increased anti-oxidant response via nuclear factor E2-related factor 2 (NRF2), result in dysregulation of FXR signaling. Several mechanistic studies have identified new dysfunctions of the cholestatic liver at cellular and molecular level, opening new venues for developing more performant therapies.

Isotschimgine alleviates nonalcoholic steatohepatitis and fibrosis via FXR agonism in mice

Farnesoid X receptor (FXR) agonist obeticholic acid (OCA) has emerged as a potential therapy for nonalcoholic fatty liver disease (NAFLD). However, the side effects of OCA may limit its application in clinics. We identified previously that isotschimgine (ITG) is a non-steroidal FXR selective agonist and has potent therapeutic effects on NAFLD in mice. Here, we aimed to evaluate the therapeutic effects of ITG on nonalcoholic steatohepatitis (NASH) and fibrosis in mice. We used methionine and choline deficient (MCD) diet-induced NASH mice, bile duct ligation (BDL), and carbon tetrachloride (CCl₄ )-treated hepatic fibrosis mice to investigate the effects of ITG on NASH, fibrosis, and cholestatic liver injury. Our results showed that ITG improved steatosis and inflammation in the liver of MCD diet-fed mice, as well as alleviated fibrosis and inflammation in the liver of CCl₄ -treated mice. Furthermore, ITG attenuated serum bile acid levels, and reduced vacuolization, inflammatory infiltration, hepatic parenchymal necrosis, and collagen accumulation in the liver of BDL mice. Mechanistically, ITG increased the expression of FXR target genes. These data suggest that ITG is an FXR agonist and may be developed as a novel therapy for NASH, hepatic fibrosis, or primary biliary cholangitis.

Unaltered Liver Regeneration in Post-Cholestatic Rats Treated with the FXR Agonist Obeticholic Acid

In a previous study, obeticholic acid (OCA) increased liver growth before partial hepatectomy (PHx) in rats through the bile acid receptor farnesoid X-receptor (FXR). In that model, OCA was administered during obstructive cholestasis. However, patients normally undergo PHx several days after biliary drainage. The effects of OCA on liver regeneration were therefore studied in post-cholestatic Wistar rats. Rats underwent sham surgery or reversible bile duct ligation (rBDL), which was relieved after 7 days. PHx was performed one day after restoration of bile flow. Rats received 10 mg/kg OCA per day or were fed vehicle from restoration of bile flow until sacrifice 5 days after PHx. Liver regeneration was comparable between cholestatic and non-cholestatic livers in PHx-subjected rats, which paralleled liver regeneration a human validation cohort. OCA treatment induced ileal Fgf15 mRNA expression but did not enhance post-PHx hepatocyte proliferation through FXR/SHP signaling. OCA treatment neither increased mitosis rates nor recovery of liver weight after PHx but accelerated liver regrowth in rats that had not been subjected to rBDL. OCA did not increase biliary injury. Conclusively, OCA does not induce liver regeneration in post-cholestatic rats and does not exacerbate biliary damage that results from cholestasis. This study challenges the previously reported beneficial effects of OCA in liver regeneration in cholestatic rats.

Bile Acids and FXR: Novel Targets for Liver Diseases

Bile acids (BAs) are evolutionally conserved molecules synthesized in the liver from cholesterol and have been shown to be essential for lipid homeostasis. BAs regulate a variety of metabolic functions via modulating nuclear and membrane receptors. Farnesoid X receptor (FXR) is the most important nuclear receptor for maintaining BA homeostasis. FXR plays a tissue-specific role in suppressing BA synthesis and promoting BA enterohepatic circulation. Disruption of FXR in mice have been implicated in liver diseases commonly occurring in humans, including cholestasis, non-alcoholic fatty liver diseases, and hepatocellular carcinoma. Strategically targeting FXR activity has been rapidly used to develop novel therapies for the prevention and/or treatment of cholestasis and non-alcoholic steatohepatitis. This review provides an updated literature review on BA homeostasis and FXR modulator development.

The Thyromimetic Sobetirome (GC-1) Alters Bile Acid Metabolism in a Mouse Model of Hepatic Cholestasis

Chronic cholestasis results from bile secretory defects or impaired bile flow with few effective medical therapies available. Thyroid hormone triiodothyronine and synthetic thyroid hormone receptor agonists, such as sobetirome (GC-1), are known to impact lipid and bile acid (BA) metabolism and induce hepatocyte proliferation downstream of Wnt/β-catenin signaling after surgical resection; however, these drugs have yet to be studied as potential therapeutics for cholestatic liver disease. Herein, GC-1 was administered to ATP binding cassette subfamily B member 4 (Abcb4^-/-; Mdr2^-/-) knockout (KO) mice, a sclerosing cholangitis model. KO mice fed GC-1 diet for 2 and 4 weeks had decreased serum alkaline phosphatase but increased serum transaminases compared with KO alone. KO mice on GC-1 also had higher levels of total liver BA due to alterations in expression of BA detoxification, transport, and synthesis genes, with the net result being retention of BA in the hepatocytes. Interestingly, GC-1 does not induce hepatocyte proliferation or Wnt/β-catenin signaling in KO mice, likely a result of decreased thyroid hormone receptor β expression without Mdr2. Therefore, although GC-1 treatment induces a mild protection against biliary injury in the early stages of treatment, it comes at the expense of hepatocyte injury and is suboptimal because of lower expression of thyroid hormone receptor β. Thus, thyromimetics may have limited therapeutic benefits in treating cholestatic liver disease.

Hepatoprotection of yangonin against hepatic fibrosis in mice via farnesoid X receptor activation

Hepatic fibrosis is a reversible would-healing response following chronic liver injury of different aetiologies and represents a major worldwide health problem. Up to date, there is no satisfactory drugs treated for liver fibrosis. The present study was to investigate hepatoprotection of yangonin against liver fibrosis induced by thioacetamide (TAA) in mice and further to clarify the involvement of farnesoid X receptor (FXR) in vivo and in vitro. Yangonin treatment remarkably ameliorated TAA-induced liver injury by reducing relative liver weight, as well as serum ALT and AST activities. Moreover, yangonin alleviated TAA-induced accumulation of bile acids through increasing the expression of bile acid efflux transporters such as Bsep and Mrp2, and reducing hepatic uptake transporter Ntcp expression, all of these are FXR-target genes. The liver sections stained by H&E indicated that the histopathological change induced by TAA was improved by yangonin. Masson and Sirius red staining indicated the obvious anti-fibrotic effect of yangonin. The mechanism of anti-fibrotic effect of yangonin was that yangonin reduced collagen content by regulating the genes involved in hepatic fibrosis including COL1-α1 and TIMP-1. Besides, yangonin inhibited hepatic stellate cell activation by reducing TGF-β1 and α-SMA expression. In addition, yangonin protected against TAA-induced hepatic inflammation via its inhibition of NF-κB and TNF-α. These hepatoprotective effects of yangonin were abrogated by guggulsterone which is a FXR antagonist. In vitro experiment further demonstrated dose-dependent activation of FXR by yangonin using dual-luciferase reporter assay. In summary, yangonin produces hepatoprotection against TAA-induced liver fibrosis via FXR activation.