Intestinal Farnesoid X Receptor Research Articles

Melatonin Ameliorates Cadmium‐Induced Liver Fibrosis Via Modulating Gut Microbiota and Bile Acid Metabolism

ABSTRACTCadmium (Cd) is a widespread environmental contaminant with high toxicity to human health. Melatonin has been shown to improve Cd‐induced liver damage. However, its mechanism has not yet been elucidated. In this study, we aimed to investigate the effects of melatonin on Cd‐induced liver damage and fibrosis. A combination of 16S rRNA gene sequencing and mass spectrometry‐based metabolomics was adopted to investigate changes in the gut microbiome and its metabolites on the regulation of melatonin in Cd‐induced liver injury and fibrosis of mice. Further, nonabsorbable antibiotics, a fecal microbiota transplantation (FMT) program and intestine‐specific farnesoid X receptor (FXR) knockout mice were employed to explore the mechanism of melatonin (MT) on liver injury and fibrosis in Cd treated mice. MT significantly improved hepatic inflammation, bile duct hyperplasia, liver damage, and liver fibrosis, with a notable decrease in liver bile acid levels in Cd‐exposed mice. MT treatment remodeled the gut microbiota, improved gut barrier function, and reduced the production of gut‐derived lipopolysaccharide (LPS). MT significantly decreased the intestinal tauro‐β‐muricholic acid levels, which are known as FXR antagonists. Notably, MT prominently activated the intestinal FXR signaling, subsequently inhibiting liver bile acid synthesis and decreasing hepatic inflammation in Cd‐exposed mice. However, MT could not ameliorate Cd‐induced liver damage and fibrosis in Abx‐treated mice. Conversely, MT still exerted a protective effect on Cd‐induced liver damage and fibrosis in FMT mice. Interestingly, MT failed to reverse liver damage and fibrosis in Cd‐exposed intestinal epithelial cell‐specific FXR gene knockout mice, indicating that intestinal FXR signaling mediated the protective effect of MT treatment. MT improves Cd‐induced liver damage and fibrosis through reshaping the intestinal flora, activating the intestinal FXR‐mediated suppression of liver bile acid synthesis and reducing LPS leakage in mice.

Effects of Therapeutically Approved Individual Bile Acids on The Development of Metabolic Dysfunction-Associated Steatohepatitis a Low Bile Acid Mouse Model

Abstract Bile acid (BA) signaling dysregulation is an important etiology for the development of Metabolic Dysfunction-associated Steatotic Liver Disease (MASLD). As diverse signaling molecules synthesized in the liver by pathways initiated with CYP7A1 and CYP27A1, BAs are endogenous modulators of farnesoid x receptor (FXR). FXR activation is crucial in maintaining BA homeostasis, regulating lipid metabolism, and suppressing inflammation. Additionally, BAs interact with membrane receptors and gut microbiota to regulate energy expenditure and intestinal health. Complex modulation of BAs in vivo and the lack of suitable animal models impede our understanding of the functions of individual BAs, especially during MASLD development. Previously, we determined that acute feeding of individual BAs differentially affects lipid, inflammation, and oxidative stress pathways in a low-BA mouse model, Cyp7a1/Cyp27a1 double knockout (DKO) mice. Currently, we investigated to what degree that cholic acid (CA), deoxycholic acid (DCA) or ursodeoxycholic acid (UDCA) at physiological concentrations impact MASLD development in DKO mice. The results showed that these three BAs varied in ability to activate hepatic and intestinal FXR, disrupt lipid homeostasis, and modulate inflammation and fibrosis. Additionally, UDCA activated intestinal FXR in these low-BA mice. Significant alterations in lipid uptake and metabolism in DKO mice following CA and DCA feeding indicate differences in cholesterol and lipid handling across genotypes. Overall, the DKO were less susceptible to weight gain, but more susceptible to MASH diet induced inflammation and fibrosis on CA and DCA supplement, while WT mice were more vulnerable to CA-induced fibrosis on control diet.

Impaired intestinal FXR signaling is involved in aberrant stem cell function leading to intestinal failure-associated liver disease in pediatric patients with short bowel syndrome.

Intestinal failure-associated liver disease (IFALD) is a serious complication of long-term parenteral nutrition in patients with short bowel syndrome (SBS), and is the main cause of death in SBS patients. Prevention of IFALD is one of the major challenges in the treatment of SBS. Impairment of intestinal barrier function is a key factor in triggering IFALD, therefore promoting intestinal repair is particularly important. Intestinal repair mainly relies on the function of intestinal stem cells (ISC), which require robust mitochondrial fatty acid oxidation (FAO) for self-renewal. Herein, we report that aberrant LGR5+ ISC function in IFALD may be attributed to impaired farnesoid X receptor (FXR) signaling, a transcriptional factor activated by steroids and bile acids. In both surgical biopsies and patient-derived organoids (PDOs), SBS patients with IFALD represented lower population of LGR5+ cells and decreased FXR expression. Moreover, treatment with T-βMCA in PDOs (an antagonist for FXR) dose-dependently reduced the population of LGR5+ cells and the proliferation rate of enterocytes, concomitant with decreased key genes involved in FAO including CPT1a. Interestingly, however, treatment with Tropifexor in PDOs (an agonist for FXR) only enhanced FAO capacity, without improvement in ISC function and enterocyte proliferation. In conclusion, these findings suggested that impaired FXR may accelerate the depletion of LGR5 + ISC population through disrupted FAO processes, which may serve as a new potential target of preventive interventions against IFALD for SBS patients.

Aromatic Amino Acids Promote Lipid Metabolism Disorders by Increasing Hepatic Bile Acid Synthesis

BackgroundObesity is a progressive metabolic disease that begins with lipid metabolism disorders. Aromatic amino acids (AAAs), including tryptophan, phenylalanine, and tyrosine, have diverse biological activities as nutrients. However, the underlying mechanisms by which AAAs affect lipid metabolism are unclear. ObjectivesThis study was designed to investigate the possible roles and underlying molecular mechanisms of AAA in the pathogenesis of lipid metabolism disorders. MethodsWe added an AAA mixture to the high-fat diet (HFD) of mice. Glucose tolerance test was recorded. Protein expression of hepatic bile acid (BA) synthase and mRNA expression of BA metabolism-related genes were determined. Hepatic BA profiles and gut microbial were also determined in mice. ResultsThe results showed that AAA significantly increased body weight and white adipose tissue, aggravated liver injury, impaired glucose tolerance and intestinal integrity, and significantly increased hepatic BA synthesis by inhibiting intestinal farnesoid X receptor (FXR). Moreover, AAA increased the content of total BA in the liver and altered the hepatic BA profile, with elevated levels of lithocholic acid, glycochenodeoxycholic acid, and glycoursodeoxycholic acid. AAA markedly increased the levels of proteins involved in BA synthesis (cholesterol 7α-hydroxylase and oxysterol 7α-hydroxylase) and inhibited the intestinal FXR. Gut microbial composition also changed, reducing the abundance of some beneficial bacteria, such as Parvibacter and Lactobacillus. ConclusionsUnder HFD conditions, AAAs stimulate BA synthesis in both the classical and alternative pathways, leading to aggravation of liver injury and fat deposition. Excessive intake of AAA disrupts BA metabolism and contributes to the development of lipid metabolism disorders, suggesting that AAA may be a causative agent of lipid metabolism disorders.

Development of Cilofexor, an intestinally-biased Farnesoid X Receptor agonist, for the treatment of fatty liver disease.

The farnesoid X receptor (FXR) is a nuclear receptor that controls bile acid, lipid, and cholesterol metabolism. FXR-targeted drugs have shown promise in late-stage clinical trials for non-alcoholic steatohepatitis. Herein, we used clinical results from our first non-steroidal FXR agonist, Px-102 (4-[2-[2-chloro-4-[[5-cyclopropyl-3-(2,6-dichlorophenyl)-4-isoxazolyl]methoxy]phenyl]cyclopropyl] benzoic acid), to develop cilofexor, a potent, non-steroidal FXR agonist with a more manageable safety profile. Px-102 demonstrated the anticipated pharmacodynamic (PD) effects in healthy volunteers but caused a 2-fold increase in alanine aminotransferase (ALT) activity and changes in cholesterol levels. These data guided development of a high fat diet mouse model to screen FXR agonists based on ALT and cholesterol changes. Cilofexor was identified to elicit only minor changes in these parameters. The differing effects of cilofexor and Px-102 on ALT/cholesterol in the model could not be explained by potency or specificity, and we hypothesized that the relative contribution of intestinal and liver FXR activation may be responsible. Gene expression analysis from rodent studies revealed that cilofexor, but not Px-102, had a bias for FXR transcriptional activity in the intestine compared to the liver. Fluorescent imaging in hepatoma cells demonstrated similar subcellular localization for cilofexor and Px-102, but cilofexor was more rapidly washed out, consistent with a lower membrane residence time contributing to reduced hepatic transcriptional effects. Cilofexor demonstrated antisteatotic and antifibrotic efficacy in rodent models and antisteatotic efficacy in a monkey model, with the anticipated PD and a manageable safety profile in human phase I studies. Significance Statement FXR (farnesoid X receptor) agonists have shown promise in treating non-alcoholic steatohepatitis and other liver diseases in the clinic, but balancing efficacy with undesired side effects has been difficult. Here, we examined the preclinical and clinical effects of the first-generation FXR agonist, Px-102 (4-[2-[2-chloro-4-[[5-cyclopropyl-3-(2,6-dichlorophenyl)-4-isoxazolyl]methoxy]phenyl]cyclopropyl] benzoic acid), to enable the selection of an analog, cilofexor, with unique properties that reduced side effects yet maintained efficacy. Cilofexor is one of few remaining FXR agonists in clinical development.

Ganoderma lucidum polysaccharide ameliorates cholesterol gallstone formation by modulating cholesterol and bile acid metabolism in an FXR-dependent manner

BackgroundCholesterol gallstone (CG) disease is a worldwide common disease characterized by cholesterol supersaturation in gallbladder bile. Ganoderma lucidum polysaccharide (GLP) has been shown to possess various beneficial effects against metabolic disorders. However, the role and underlying mechanism of GLP in CG formation are still unknown. This study aimed to determine the role of GLP in ameliorating lithogenic diet (LD)-induced CG formation.MethodsMice were fed either a normal chow diet, a LD, or LD supplemented with GLP. Real-time quantitative polymerase chain reaction (RT-qPCR) and western blotting were used to detect the expression of genes involved in cholesterol and bile acid (BA) metabolism. The BA concentrations in the ileum were quantified by liquid chromatography-tandem mass spectrometry (LC–MS/MS). The microbiota in cecal contents were characterized using 16S ribosomal RNA (16S rRNA) gene sequencing.ResultsGLP effectively alleviated CG formation induced by LD. Specifically, GLP reduced the total cholesterol (TC) levels, increased the total BA levels, and decreased the cholesterol saturation index (CSI) in gallbladder bile. The protective effect of GLP was attributed to the inhibition of farnesoid X receptor (FXR) signaling, increased hepatic BA synthesis and decreased hepatic cholesterol synthesis and secretion. GLP also altered the BA composition in the ileum, reducing FXR-agonistic BAs and increasing FXR-antagonistic BAs, which may contribute to the inhibition of intestinal FXR signaling. Additionally, GLP improved dysbiosis of the intestinal flora and reduced the serum levels of hydrogen sulfide (H2S), a bacterial metabolite that can induce hepatic FXR, thereby inhibiting hepatic FXR signaling. Moreover, the protective effect of GLP against CG formation could be reversed by both the global and gut-restricted FXR agonists.ConclusionsTaken together, GLP ameliorates CG formation by regulating cholesterol and BA metabolism in an FXR-dependent manner. Our study demonstrates that GLP may be a potential strategy for the prevention against CG disease.

Melatonin improves cholestatic liver disease via the gut-liver axis.

Cholestatic liver disease is characterized by disturbances in the intestinal microbiota and excessive accumulation of toxic bile acids (BA) in the liver. Melatonin (MT) can improve liver diseases. However, the underlying mechanism remains unclear. This study aimed to explore the mechanism of MT on hepatic BA synthesis, liver injury, and fibrosis in 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC)-fed and Mdr2-/- mice. MT significantly improved hepatic injury and fibrosis with a significant decrease in hepatic BA accumulation in DDC-fed and Mdr2-/- mice. MT reprogramed gut microbiota and augmented fecal bile salt hydrolase activity, which was related to increasing intestinal BA deconjugation and fecal BA excretion in both DDC-fed and Mdr2-/- mice. MT significantly activated the intestinal farnesoid X receptor (FXR)/fibroblast growth factor 15 (FGF-15) axis and subsequently inhibited hepatic BA synthesis in DDC-fed and Mdr2-/- mice. MT failed to improve DDC-induced liver fibrosis and BA synthesis in antibiotic-treated mice. Furthermore, MT provided protection against DDC-induced liver injury and fibrosis in fecal microbiota transplantation mice. MT did not decrease liver injury and fibrosis in DDC-fed intestinal epithelial cell-specific FXR knockout mice, suggesting that the intestinal FXR mediated the anti-fibrosis effect of MT. In conclusion, MT ameliorates cholestatic liver diseases by remodeling gut microbiota and activating intestinal FXR/FGF-15 axis-mediated inhibition of hepatic BA synthesis and promotion of BA excretion in mice.

Discovery of 4-aminophenylacetamide derivatives as intestine-specific farnesoid X receptor antagonists for the potential treatment of nonalcoholic steatohepatitis

Farnesoid X receptor (FXR) plays a key role in bile acid homeostasis, inflammation, fibrosis, lipid and glucose metabolism and is emerging as a promising therapeutic target for nonalcoholic steatohepatitis (NASH). Emerging evidence suggested that intestine-specific FXR antagonists exhibited remarkable metabolic improvements and slowed NASH progression. In this study, we discovered several potent FXR antagonists using a multistage ligand- and structure-based virtual screening approach. Notably, compound V023-9340, which possesses a 4-aminophenylacetamide scaffold, emerged as the most potent FXR antagonist with an IC50 value of 4.27 μM. In vivo, V023-9340 demonstrated selective accumulation in the intestine, substantially ameliorating high-fat diet (HFD)-induced NASH in mice by mitigating hepatic steatosis and inflammation. Mechanistic studies revealed that V023-9340 strongly inhibited intestinal FXR while concurrently feedback-activated hepatic FXR. Further structure-activity relationship optimization employing V023-9340 has resulted in the synthesis of a more efficacious compound V02-8 with an IC50 value of 0.89 μM, which exhibited a 4.8-fold increase in FXR antagonistic activity compared to V023-9340. In summary, 4-aminophenylacetamide derivative V023-9340 represented a novel intestine-specific FXR antagonist and showed improved effects against HFD-induced NASH in mice, which may serve as a promising lead in discovering potential therapeutic drugs for NASH treatment.

Inhibition of intestinal FXR activity as a possible mechanism for the beneficial effects of a probiotic mix supplementation on lipid metabolism alterations and weight gain in mice fed a high fat diet

ABSTRACT Supplementation with probiotics has emerged as a promising therapeutic tool to manage metabolic diseases. We investigated the effects of a mix of Bifidobacterium animalis subsp. lactis LA804 and Lactobacillus gasseri LA806 on high-fat (HF) diet -induced metabolic disease in mice. Supplementation with the probiotic mix in HF diet-fed mice (HF-Pr2) reduced weight and fat mass gains, decreased hepatic lipid accumulation, and lowered plasma triglyceride peak during an oral lipid tolerance test. At the molecular level, the probiotic mix protected against HF-induced rise in mRNA levels of genes related to lipid uptake, metabolism, and storage in the liver and white adipose tissues, and strongly decreased mRNA levels of genes related to inflammation in the white adipose tissue and to oxidative stress in the liver. Regarding intestinal homeostasis, the probiotic mix did not prevent HF-induced gut permeability but slightly modified microbiota composition without correcting the dysbiosis induced by the HF diet. Probiotic supplementation also modified the cecal bile acid (BA) profile, leading to an increase in the Farnesoid-X-Receptor (FXR) antagonist/agonist ratio between BA species. In agreement, HF-Pr2 mice exhibited a strong inhibition of FXR signaling pathway in the ileum, which was associated with lipid metabolism protection. This is consistent with recent reports proposing that inhibition of intestinal FXR activity could be a potent mechanism to overcome metabolic disorders. Altogether, our results demonstrate that the probiotic mix evaluated, when administered preventively to HF diet-fed mice could limit obesity and associated lipid metabolism disorders, likely through the inhibition of FXR signaling in the intestinal tract.

Celastrol as an intestinal FXR inhibitor triggers tripolide-induced intestinal bleeding: Underlying mechanism of gastrointestinal injury induced by Tripterygium wilfordii

BackgroundTripterygium wilfordii has been widely used for the treatment of rheumatoid arthritis, which is frequently accompanied by severe gastrointestinal damage. The molecular mechanism underlying the gastrointestinal injury of Tripterygium wilfordii are yet to be elucidated. MethodsTransmission electron microscopy, and pathological and biochemical analyses were applied to assess intestinal bleeding. Metabolic changes in the serum and intestine were determined by metabolomics. In vivo (time-dependent effect and dose-response) and in vitro (double luciferase reporter gene system, DRATs, molecular docking, HepG2 cells and small intestinal organoids) studies were used to identify the inhibitory role of celastrol on intestinal farnesoid X receptor (FXR) signaling. Fxr-knockout mice and FXR inhibitors and agonists were used to evaluate the role of FXR in the intestinal bleeding induced by Tripterygium wilfordii. ResultsCo-treatment with triptolide + celastrol (from Tripterygium wilfordii) induced intestinal bleeding in mice. Metabolomic analysis indicated that celastrol suppressed intestinal FXR signaling, and further molecular studies revealed that celastrol was a novel intestinal FXR antagonist. In Fxr-knockout mice or the wild-type mice pre-treated with pharmacological inhibitors of FXR, triptolide alone could activate the duodenal JNK pathway and induce intestinal bleeding, which recapitulated the pathogenic features obtained by co-treatment with triptolide and celastrol. Lastly, intestinal bleeding induced by co-treatment with triptolide and celastrol could be effectively attenuated by the FXR or gut-restricted FXR agonist through downregulation of the duodenal JNK pathway. ConclusionsThe synergistic effect between triptolide and celastrol contributed to the gastrointestinal injury induced by Tripterygium wilfordii via dysregulation of the FXR-JNK axis, suggesting that celastrol should be included in the quality standards system for evaluation of Tripterygium wilfordii preparations. Determining the mechanism of the FXR-JNK axis in intestinal bleeding could aid in the identification of additional therapeutic targets for the treatment of gastrointestinal hemorrhage diseases. This study also provides a new standard for the quality assessment of Tripterygium wilfordii used in the treatment of gastrointestinal disorders.

Aflatoxin B1 induces liver injury by disturbing gut microbiota-bile acid-FXR axis in mice.

Aflatoxin B1 (AFB1) is one of major pollutant in food and feed worldwide. The purpose of this study is to investigate the mechanism of AFB1-induced liver injury. Our results showed that AFB1 caused hepatic bile duct proliferation, oxidative stress, inflammation and liver injury in mice. AFB1 exposure induced gut microbiota dysbiosis and reduced fecal bile salt hydrolase (BSH) activity. AFB1 exposure promoted hepatic bile acid (BA) synthesis and changed intestinal BA metabolism, especially increased intestinal conjugated bile acids levels. AFB1 exposure inhibited intestinal farnesoid X receptor (FXR)/fibroblast growth factor 15 (FGF-15) signaling. Furthermore, the mice received fecal microbiota transplantation from AFB1-treated mice induced liver injury, reduced intestinal FXR signaling and increased hepatic BA synthesis. Finally, the intestine-restricted FXR agonist treatment decreased hepatic BA synthesis, ROS level, inflammation and liver injury in AFB1-treated mice. This study suggests that modifying the gut microbiota, altering intestinal BA metabolism and/or activating intestinal FXR/FGF-15 signaling may be of value for the treatment of AFB1-induced liver disease.

Polysaccharide from Angelica sinensis with medicinal and edible purposes ameliorated NAFLD by the bile acids mediated activation of FXR

Liver and gut communicates with each other through metabolites and the gut-liver axis plays a crucial role in lipid metabolism. Enterohepatic bile acid circulation is an important constitution of gut-liver axis. Farnesoid X receptor (FXR)，a bile acid mediated nuclear receptor, is promising therapeutic targets for the non-alcoholic fatty liver disease (NAFLD). More and more studies have confirmed the effects of Angelica sinensis polysaccharide (ASP) on liver protection and lipid regulation. However, little attention has been paid to the role of ASP on the gut-liver axis, which is crucial to clarify how ASP play a role in liver protection after oral administration. In vivo and in vitro models of NAFLD were established to examine the effect of ASP on hepatic fat accumulation. Our results showed that ASP could alleviate liver fat accumulation. However, the expression of FXR was not changed when ASP directly acting on hepatocytes, while ASP could change the expression of FXR in liver and intestine of mice after oral administration. In addition, our results showed that ASP could promote the excretion of bile acids, thereby increasing cholesterol metabolism. Our research provided a new concept for the mechanism of ASP regulating liver lipid metabolism and exerting liver protection.

Discovery of the First-in-Class Intestinal Restricted FXR and FABP1 Dual Modulator ZLY28 for the Treatment of Nonalcoholic Fatty Liver Disease.

The prevalence of nonalcoholic steatohepatitis (NASH) is increasing rapidly worldwide, and NASH has become a serious problem for human health. Recently, the selective activation of the intestinal farnesoid X receptor (FXR) was considered as a more promising strategy for the treatment of NASH with lesser side effects due to reduced systemic exposure. Moreover, the inhibition of intestinal fatty acid binding protein 1 (FABP1) alleviated obesity and NASH by reducing dietary fatty acid uptake. In this study, the first-in-class intestinal restricted FXR and FABP1 dual-target modulator ZLY28 was discovered by comprehensive multiparameter optimization studies. The reduced systemic exposure of ZLY28 might provide better safety by decreasing the on- and off-target side effects in vivo. In NASH mice, ZLY28 exerted robust anti-NASH effects by inhibiting FABP1 and activating the FXR-FGF15 signaling pathway in the ileum. With the above attractive efficacy and preliminary safety profiles, ZLY28 is worthy of further evaluation as a novel anti-NASH agent.

Intestinal Farnesoid X Receptor Modulates Duodenal Surface Area but Does Not Control Glucose Absorption in Mice.

Bile acids facilitate the intestinal absorption of dietary lipids and act as signalling molecules in the maintenance of metabolic homeostasis. Farnesoid X receptor (FXR) is a bile acid-responsive nuclear receptor involved in bile acid metabolism, as well as lipid and glucose homeostasis. Several studies have suggested a role of FXR in the control of genes regulating intestinal glucose handling. We applied a novel dual-label glucose kinetic approach in intestine-specific FXR-/- mice (iFXR-KO) to directly assess the role of intestinal FXR in glucose absorption. Although iFXR-KO mice showed decreased duodenal expression of hexokinase 1 (Hk1) under obesogenic conditions, the assessment of glucose fluxes in these mice did not show a role for intestinal FXR in glucose absorption. FXR activation with the specific agonist GS3972 induced Hk1, yet the glucose absorption rate remained unaffected. FXR activation increased the duodenal villus length in mice treated with GS3972, while stem cell proliferation remained unaffected. Accordingly, iFXR-KO mice on either chow, short or long-term HFD feeding displayed a shorter villus length in the duodenum compared to wild-type mice. These findings indicate that delayed glucose absorption reported in whole-body FXR-/- mice is not due to the absence of intestinal FXR. Yet, intestinal FXR does have a role in the small intestinal surface area.

Sodium cholate ameliorates nonalcoholic steatohepatitis by activation of FXR signaling.

Non-alcoholic steatohepatitis (NASH) has become a major cause of liver transplantation and liver-associated death. The gut-liver axis is a potential therapy for NASH. Sodium cholate (SC) is a choleretic drug whose main component is bile acids and has anti-inflammatory, antifibrotic, and hepatoprotective effects. This study aimed to investigate whether SC exerts anti-NASH effects by the gut-liver axis. Mice were fed with an high-fat and high-cholesterol (HFHC) diet for 20 weeks to induce NASH. Mice were daily intragastric administrated with SC since the 11th week after initiation of HFHC feeding. The toxic effects of SC on normal hepatocytes were determined by CCK8 assay. The lipid accumulation in hepatocytes was virtualized by Oil Red O staining. The mRNA levels of genes were determined by real-time quantitative PCR assay. SC alleviated hepatic injury, abnormal cholesterol synthesis, and hepatic steatosis and improved serum lipid profile in NASH mice. In addition, SC decreased HFHC-induced hepatic inflammatory cell infiltration and collagen deposition. The target protein-protein interaction network was established through Cytoscape software, and NR1H4 [farnesoid x receptor (FXR)] was identified as a potential target gene for SC treatment in NASH mice. SC-activated hepatic FXR and inhibited CYP7A1 expression to reduce the levels of bile acid. In addition, high-dose SC attenuated the abnormal expression of cancer markers in NASH mouse liver. Finally, SC significantly increased the expression of FXR and FGF15 in NASH mouse intestine. Taken together, SC ameliorates steatosis, inflammation, and fibrosis in NASH mice by activating hepatic and intestinal FXR signaling so as to suppress the levels of bile acid in NASH mouse liver and intestine.

Pharmacokinetics, pharmacodynamics, safety and tolerability of cilofexor, a novel nonsteroidal Farnesoid Xreceptor agonist, in healthy volunteers.

Cilofexor is a nonsteroidal farnesoid X receptor (FXR) agonist being evaluated for treatment of nonalcoholic steatohepatitis (NASH) and primary sclerosing cholangitis (PSC). This work characterized the pharmacokinetics, pharmacodynamic, safety, and tolerability of cilofexor in healthy participants. Cilofexor single and multiple once-daily doses (10 to 300 mg fasting or fed and twice-daily doses [15 and 50 mg; fed]; tablet formulation) were evaluated. In each cohort, participants were randomized to active drug or placebo in a 4:1 ratio (planned n=15/cohort). Multiple dosing was for 14 days. Pharmacokinetic and pharmacodynamic samples were collected and safety and tolerability were assessed. Overall, 120 participants were enrolled in the study and 118 participants received at least one dose of study drug. Cilofexor pharmacokinetics followed bi-exponential disposition and its exposure increased in a less-than-dose-proportional manner over the 10 to 300 mg dose range, with no significant accumulation with repeated dosing. Moderate-fat meal reduced cilofexor area under the plasma concentration versus time curve (AUC) by 21% to 45%. Cilofexor increased plasma levels of fibroblast growth factor19 (FGF19) and reduced the serum bile acid intermediate 7α-hydroxy-4-cholesten-3-one (C4) and bile acids in an exposure-dependent manner. Cilofexor doses >30 mg appeared to achieve the plateau of intestinal FXR activation. Cilofexor was generally well tolerated; all treatment-emergent adverse events (TEAEs) were mild or moderate in severity, with headache being the most frequently observed TEAE. The pharmacokinetics pharmacodynamic safety, and tolerability results from this study supported further evaluations, and informed dose selection, of cilofexor in phase II studies in patients with NASH and PSC.

Farnesoid X receptor is inhibited after ileum transposition in diabetic rats: its hypoglycemic effect

Background: Aim to investigate bile acid profile changes and the Farnesoid X receptor (FXR) status after ileotransposition (IT), and reveal its possible hypoglycemic mechanism. Methods: Twenty male diabetic rats were randomly assigned into the IT group and the sham IT (SH) group. Bile acid profiles were measured using an ultra-performance liquid chromatography-tandem mass spectrometry. Glucose metabolism was monitored after oral administration of FXR inhibitor and agonist. And the expression of key FXR target genes were measured. Results: The levels of β-muricholic acid (P = 0.047), tauro-α-muricholic acid and tauro-β-muricholic acid (P < 0.001) in plasma in the IT group were higher than those in the SH group, and the levels of taurocholic acid (P = 0.049) and turoursodeoxycholic acid (P = 0.030) were lower than those in the SH group. After inhibition of intestinal FXR, the glucose metabolism in the SH group was improved. When FXR agonist was given, the blood glucose level was increased in both groups. After sacrifice, the levels of glycoursodeoxycholic acid, tauro-α-muricholic acid and tauro-β-muricholic acid in liver and ileum tissues were higher than those in the SH group (P < 0.05), the level of α- muricholic acid (P < 0.001) in liver tissues were lower than that in the SH group. Moreover, the expression of CYP7A1 mRNA (P < 0.001) and FGF15 mRNA (P = 0.001) in the IT group was significantly higher, and the expression of PEPCK mRNA (P = 0.004), SREPB1c mRNA (P = 0.005) and SRB1 mRNA (P = 0.001) were significantly lower than that in the SH group. Conclusions: We demonstrate a remarkable heterogeneity of BA profiles after IT, FXR activation might has a detrimental effect on glucose metabolism.

FXR mediates ILC-intrinsic responses to intestinal inflammation

The pleiotropic actions of the Farnesoid X Receptor (FXR) are required for gut health, and reciprocally, reduced intestinal FXR signaling is seen in inflammatory bowel diseases (IBDs). Here, we show that activation of FXR selectively in the intestine is protective in inflammation-driven models of IBD. Prophylactic activation of FXR restored homeostatic levels of pro-inflammatory cytokines, most notably IL17. Importantly, these changes were attributed to FXR regulation of innate lymphoid cells (ILCs), with both the inflammation-driven increases in ILCs, and ILC3s in particular, and the induction of Il17a and Il17f in ILC3s blocked by FXR activation. Moreover, a population of ILC precursor-like cells increased with treatment, implicating FXR in the maturation/differentiation of ILC precursors. These findings identify FXR as an intrinsic regulator of intestinal ILCs and a potential therapeutic target in inflammatory intestinal diseases.

Hepatic thyroid hormone signalling modulates glucose homeostasis through the regulation of GLP-1 production via bile acid-mediated FXR antagonism

Thyroid hormones (TH) regulate systemic glucose metabolism through incompletely understood mechanisms. Here, we show that improved glucose metabolism in hypothyroid mice after T3 treatment is accompanied with increased glucagon-like peptide-1 (GLP-1) production and insulin secretion, while co-treatment with a GLP-1 receptor antagonist attenuates the effects of T3 on insulin and glucose levels. By using mice lacking hepatic TH receptor β (TRβ) and a liver-specific TRβ-selective agonist, we demonstrate that TRβ-mediated hepatic TH signalling is required for both the regulation of GLP-1 production and the insulinotropic and glucose-lowering effects of T3. Moreover, administration of a liver-targeted TRβ-selective agonist increases GLP-1 and insulin levels and alleviates hyperglycemia in diet-induced obesity. Mechanistically, T3 suppresses Cyp8b1 expression, resulting in increased the levels of Farnesoid X receptor (FXR)-antagonistic bile acids, thereby potentiating GLP-1 production and insulin secretion by repressing intestinal FXR signalling. T3 correlates with both plasma GLP-1 and fecal FXR-antagonistic bile acid levels in people with normal thyroid function. Thus, our study reveals a role for hepatic TH signalling in glucose homeostasis through the regulation of GLP-1 production via bile acid-mediated FXR antagonism.

Glycine-β-muricholic acid antagonizes the intestinal farnesoid X receptor-ceramide axis and ameliorates NASH in mice.

Nonalcoholic steatohepatitis (NASH) is a rapidly developing pathology around the world, with limited treatment options available. Some farnesoid X receptor (FXR) agonists have been applied in clinical trials for NASH, but side effects such as pruritus and low-density lipoprotein elevation have been reported. Intestinal FXR is recognized as a promising therapeutic target for metabolic diseases. Glycine-β-muricholic acid (Gly-MCA) is an intestine-specific FXR antagonist previously shown to have favorable metabolic effects on obesity and insulin resistance. Herein, we identify a role for Gly-MCA in the pathogenesis of NASH, and explore the underlying molecular mechanism. Gly-MCA improved lipid accumulation, inflammatory response, and collagen deposition in two different NASH models. Mechanistically, Gly-MCA decreased intestine-derived ceramides by suppressing ceramide synthesis-related genes via decreasing intestinal FXR signaling, leading to lower liver endoplasmic reticulum (ER) stress and proinflammatory cytokine production. The role of bile acid metabolism and adiposity was excluded in the suppression of NASH by Gly-MCA, and a correlation was found between intestine-derived ceramides and NASH severity. This study revealed that Gly-MCA, an intestine-specific FXR antagonist, has beneficial effects on NASH by reducing ceramide levels circulating to liver via lowering intestinal FXR signaling, and ceramide production, followed by decreased liver ER stress and NASH progression. Intestinal FXR is a promising drug target and Gly-MCA a novel agent for the prevention and treatment of NASH.