FXR Expression Research Articles

Dietary ferulic acid supplementation improved cottonseed meal-based diet utilization by enhancing intestinal physical barrier function and liver antioxidant capacity in grass carp (Ctenopharyngodon Idellus).

The present study explored the effects of ferulic acid (FA) supplementation in cottonseed meal (CSM)-based diets on grass carp growth performance, feed utilization, liver antioxidation status, and intestinal physical barrier function. Here, four experimental diets supplemented with FA at graded levels (0, 50, 100 and 200 mg/kg) and CSM as the main protein source (384.6 g/kg feed) for an 8-week feeding trial. Our results indicated that 200 mg/kg FA supplementation in a CSM-based diet significantly improved growth performance [including final body weight (FBW), weight gain rate, and specific growth rate] and feed utilization [including feed conversion ratio and protein efficiency ratio] in grass carp (p < 0.05). The results of polynomial regression analysis based on FBW recommended that the optimal dose for FA supplementation was 204 mg/kg. Compared with that no FA supplementation, 200 mg/kg FA supplementation significantly reduced liver malondialdehyde levels and increased glutathione reductase activities (p < 0.05) and 100 mg/kg FA supplementation significantly increased liver total superoxide dismutase activities and reduced blood alanine transaminase levels (p < 0.05). Compared with the control group, 100 mg/kg FA supplementation also led to significantly increased mRNA expression of zo-1, zo-2, occludin, claudin-b, claudin-3, claudin-7a, and claudin-12, encoding intestinal tight junction proteins (p < 0.05). Notably, FA supplementation could reduce lipid deposition by regulating bile acid (BA) secretion. In this study, 100 and 200 mg/kg FA supplementation significantly increased blood and liver total BA levels, respectively (p < 0.05); 100 mg/kg FA also significantly activated mRNA expressions of fxr and cyp7a1 (p < 0.05). Furthermore, the whole-body composition results presented that FA treatment relieved lipid deposition, particularly 50 and 200 mg/kg FA supplementation (p < 0.05). Moreover, triglyceride and total cholesterol levels were significantly lower and high-density lipoprotein levels were significantly higher with 200 mg/kg FA supplementation than with no FA supplementation (p < 0.05). Taken together, the results indicated that FA may be a beneficial feed additive to boost fish growth performance and increase CSM utilization.

Screening of Biomarkers and Toxicity Mechanisms of Rifampicin-Induced Liver Injury Based on Targeted Bile Acid Metabolomics.

Rifampicin (RIF) is a critical first-line drug for tuberculosis. However, long-term or high-dose treatment with RIF can induce severe liver injury; the underlying mechanism of this effect has not yet been clarified. This study was performed to screen reliable and sensitive biomarkers in serum bile acids (BAs) using targeted BA metabolomics and evaluate the toxicity mechanisms underlying RIF-induced liver injury through the farnesoid x receptor (Fxr)-multidrug resistance-associated proteins (Mrps) signaling pathway. Thirty-two Institute of Cancer Research mice were randomly divided into four groups, and normal saline, isoniazid 75 mg/kg + RIF 177 mg/kg (RIF-L), RIF-L, or RIF 442.5 mg/kg (RIF-H) was orally administered by gavage for 21 days. After treatment, changes in serum biochemical parameters, hepatic pathological conditions, BA levels, Fxr expression, and BA transporter levels were measured. RIF caused notable liver injury and increased serum cholic acid (CA) levels. Decline in the serum secondary BAs (deoxycholic acid, lithocholic acid, taurodeoxycholic acid, and tauroursodeoxycholic acid) levels led to liver injury in mice. Serum BAs were subjected to metabolomic assessment using partial least squares discriminant and receiver operating characteristic curve analyses. CA, DCA, LCA, TDCA, and TUDCA are potential biomarkers for early detection of RIF-induced liver injury. Furthermore, RIF-H reduced hepatic BA levels and elevated serum BA levels by suppressing the expression of Fxr and Mrp2 messenger ribonucleic acid (mRNA) while inducing that of Mrp3 and Mrp4 mRNAs. These findings provide evidence for screening additional biomarkers based on targeted BA metabolomics and provide further insights into the pathogenesis of RIF-induced liver injury.

Dihydroartemisinin promoted FXR expression independent of YAP1 in hepatocellular carcinoma.

Loss of FXR, one of bile acid receptors, enlarged livers. Yes-associated protein 1 (YAP1), a dominant oncogene, promotes hepatocellular carcinoma (HCC). However, the relationship between FXR and YAP1 was unspecified in bile acid homeostasis in HCC. Here, we used TIMER2.0, the Cancer Genome Atlas (TCGA) Database, and Kaplan-Meier Plotter Database and discovered that FXR was positively correlated with better prognosis in liver cancer patients. Our previous research showed that dihydroartemisinin (DHA) inhibited cell proliferation in HepG2 and HepG22215 cells. However, the relationship of YAP1 and the bile acid receptor FXR remains elusive during DHA treatment. Furthermore, we showed that DHA improved FXR and reduced YAP1 in the liver cancer cells and mice. Additionally, the expression of nucleus protein FXR was enhanced in Yap1LKO mice with liver cancer. DHA promoted the expression level of whole and nuclear protein FXR independent of YAP1 in Yap1LKO mice with liver cancer. DHA declined cholesterol 7α-hydroxylase, but not sterol 27-hydroxylase, and depressed cholic acid and chenodeoxycholic acid of liver tissue in Yap1LKO mice with liver cancer. Generally, our results suggested that DHA improved FXR and declined YAP1 to suppress bile acid metabolism. Thus, we suggested that FXR acted as a potential therapeutic target in HCC.

Gut microbiome in non-alcoholic fatty liver disease associated hepatocellular carcinoma: Current knowledge and potential for therapeutics.

Metabolic diseases such as nonalcoholic fatty liver disease (NAFLD) are rising in incidence and are an increasingly common cause of cirrhosis and hepatocellular carcinoma (HCC). The gut microbiome is closely connected to the liver via the portal vein, and has recently been identified as a predictor of liver disease state. Studies in NAFLD, cirrhosis and HCC have identified certain microbial signatures associated with these diseases, with the disease-associated microbiome changes collectively referred to as dysbiosis. The pathophysiologic underpinnings of these observations are an area of ongoing investigation, with current evidence demonstrating that the gut microbiome can influence liver disease and carcinogenesis via effects on intestinal permeability (leaky gut) and activation of the innate immune system. In the innate immune system, pathogen recognition receptors (Toll like receptors) on resident liver cells and macrophages cause liver inflammation, fibrosis, hepatocyte proliferation and reduced antitumor immunity, leading to chronic liver disease and carcinogenesis. Dysbiosis-associated changes include increase in secondary bile acids and reduced expression of FXR (nuclear receptor), which have also been associated with deleterious effects on lipid and carbohydrate metabolism associated with progressive liver disease. Longitudinal experimental and clinical studies are needed in different populations to examine these questions further. The role of therapeutics that modulate the microbiome is an emerging field with experimental studies showing the potential of diet, probiotics, fecal microbiota transplantation and prebiotics in improving liver disease in experimental models. Clinical studies are ongoing with preliminary evidence showing improvement in liver enzymes and steatosis. The microbial profile is different in responders to cancer immunotherapy including liver cancer, but whether or not manipulation of the microbiome can be utilized to affect response is being investigated.

Ameliorative effect of mangiferin on high fat diet - Diethylnitrosamine induced non-alcoholic steatohepatitis rats

Non-alcoholic steatohepatitis (NASH) is a serious form of nonalcoholic fatty liver disease (NAFLD) which leads to fibrosis, cirrhosis and liver failure. This study is aimed to investigate the therapeutic effect of mangiferin , a major glucoxanthone of Mangifera indica L., on NASH. Pharmacokinetic property of mangiferin was assessed using DataWarrior tool and the compound was docked with PPARα protein using Autodock tool. Anti-NASH efficacy of mangiferin was assessed in HFD-DEN induced Wistar rats at 50 and 100 mg/kg b. w. concentrations. Treatment with mangiferin significantly lowered plasma and liver lipid levels; it also reduced transaminase levels. The ultrasonography and histopathological studies showed reduction of steatosis and inflammation in the liver with mangiferin treatment. The treatment increased the hepatic mRNA expressions of PPARα and FXR . These preliminary evidences gave an insight on the anti-NASH potential of mangiferin; further intensive studies are needed to establish it. • Mangiferin was isolated from Mangifera indica . • Mangiferin reduced the liver damage in HFD-DEN fed rats at 50 and 100 mg/kg b. w. • Mangiferin upregulated the PPARα expression in HFD-DEN fed rats. • Mangiferin bound to a new conservative target in PPARα protein with less energy.

Livogrit Prevents Methionine-Cystine Deficiency Induced Nonalcoholic Steatohepatitis by Modulation of Steatosis and Oxidative Stress in Human Hepatocyte-Derived Spheroid and in Primary Rat Hepatocytes

ABSTRACT The prevalence of nonalcoholic steatohepatitis (NASH), characterized by fatty liver, oxidative injury, and inflammation, has considerably increased in the recent years. Due to the complexity of NASH pathogenesis, compounds which can target different mechanisms and stages of NASH development are required. A robust screening model with translational capability is also required to develop therapies targeting NASH. In this study, we used HepG2 spheroids and rat primary hepatocytes to evaluate the potency of Livogrit, a tri-herbal Ayurvedic prescription medicine, as a hepatoprotective agent. NASH was developed in the cells via methionine and cystine-deficient cell culture media. Livogrit at concentration of 30 µg/mL was able to prevent NASH development by decreasing lipid accumulation, ROS production, AST release, NFκB activation and increasing lipolysis, GSH (reduced glutathione), and mitochondrial membrane potential. This study suggests that Livogrit might reduce the lipotoxicity-mediated ROS generation and subsequent production of inflammatory mediators as evident from the increased gene expression of FXR, FGF21, CHOP, CXCL5, and their normalization due to Livogrit treatment. Taken together, Livogrit showed the potential as a multimodal therapeutic formulation capable of attenuating the development of NASH. Our study highlights the potential of Livogrit as a hepatoprotective agent with translational possibilities.

Addition of berberine to formulated feed changes the glucose utilisation, intestinal microbiota and serum metabolites of Largemouth bass (Micropterus salmoides)

Largemouth bass (Micropterus salmoides) is extremely intolerant to carbohydrates in diets. To address this problem, this work studied the effects of berberine (BBR), a Chinese herbal extract with the serum glucose-lowering activity in mammals, on regulating the serum glucose and intestinal microbiota in largemouth bass. The changes in glucose metabolism-related genes and serum metabolites were also determined to explore the possible pathways and underlying mechanisms. Our results showed that BBR reduced the serum contents of total cholesterol, triglyceride and glucose, and increased intestinal farnesoid X receptor (fxr) expression in largemouth bass (P < 0.001). BBR dramatically altered fxr downstream glycolysis- and gluconeogenesis-related genes, along with their enzyme activities (P < 0.001). Moreover, BBR changed the diversity of the intestinal microbiota, including decreasing the abundance of Fusobacteria and elevating those of Firmicutes and Proteobacteria (P < 0.001). Correlation analysis showed that the above increased bacteria in BBR group were strongly and positively related to the intestinal fxr genes. It was further found that the bacterial functions of “Glycolysis/Gluconeogenesis,” “Nitrogen metabolism” and “Energy metabolism” were enriched in the BBR group. Serum metabolomics analysis showed that BBR supplementation changed the metabolic processes, especially the metabolism of amino acids and carbohydrates. Correlation analysis found that, in the BBR group, the decreased abundance of Cetobacterium and increased abundances of Lachnospiracea and Ruminococcaceae were significantly correlated with the serum metabolites with serum glucose-lowering activity including butyrate, inosine, and N-methylhydantoin. Overall, these results confirmed that dietary supplementation of BBR decreased the serum glucose level of largemouth bass, possibly related to the changes of intestinal bacteria and their regulation on the intestinal-FXR signal pathways. Dietary BBR would provide new ways to improve the carbohydrate metabolism of largemouth bass.

Uridine dynamic administration affects the circadian variation of bile acid metabolism in high-fat-diet-fed mice

High-fat diet (HFD) is demonstrated to disturb the bile acid metabolism. The rhythm of bile acid metabolism can also be affected by uridine, whose metabolism exhibits a daily rhythm. However, the mechanism of dynamic uridine administration affecting bile acid during HFD remains unclear. In this study, C57BL/6J mice were fed HFD (the control group; CON) or HFD with oral administration of uridine in the daytime (DUR) and nighttime (NUR) to investigate the mechanism of the effect of uridine on the bile acid. This study showed that the mRNA expression of uridine transporters and circadian clock genes in the jejunum was affected by zeitgeber time (ZT) (P < 0.001). Genes related to the metabolism of pyrimidines in the liver showed a high dependence on daily rhythm (P < 0.01), and DUR remarkably up-regulated the expression of ribonucleotide reductase regulatory subunit M2 (RRM2) (P < 0.05) compared to the CON group. Importantly, the mRNA expression of bile acids nuclear receptors, bile acid synthesis, and transporters in the liver showed significantly rhythmically changed (P < 0.05), and the expression of cholesterol 7-alpha-hydroxylase (CYP7A1), fibroblast growth factor receptor 4 (FGFR4), Na+/taurocholate co transporting polypeptide (NTCP), and bile salt export pump (BSEP) mRNAs of mice with uridine administration increased significantly (P < 0.05). The mRNA expression of the transporters of cholesterol and bile acids in the ileum was also affected by ZT (P < 0.01) and significantly dependent on uridine administration (P < 0.05). The expression of FXR and SHP was significantly affected by ZT and uridine, respectively. In conclusion, dynamic administration of uridine could regulate the rhythm of gene expression of pyrimidine and bile acid metabolism in the liver and ileum of HFD-fed mice, which contributed to the further study of circadian rhythmic physiological and pathological changes of bile acids.

Different typical dietary lipid consumption affects the bile acid metabolism and the gut microbiota structure: an animal trial using Sprague-Dawley rats.

The palm oil (PO), leaf lard oil (LO), rapeseed oil (RO), sunflower oil (SO) and linseed oil (LN) are five of the most typical dietary lipids in most Asian countries. However, their influences on gut health, and the connections between the fatty acid composition, the gut microbiota, and the bile acid metabolism are not fully understood. In the present study, results showed that compared with polyunsaturated fatty acid (PUFA)-rich SO and LN, the saturated fatty acid (SFA)-rich and monounsaturated fatty acid (MUFA)-rich PO, LO and RO were more likely to decrease the re-absorption of bile acid in the colon, which was probably caused by their different role in modulating the gut microbiota structure. LO consumption significantly up-regulated the Cyp27a1, FXR and TGR5 gene expression level (P < 0.05). The correlation results suggested that the C18:0 was significantly positive correlated with these three genes, indicating that intake of SFA-rich dietary lipids, especially for the C18:0, could specifically increase the bile acid production by stimulating the bile acid alternative synthesis pathway. Although the bile acid receptor expression in the colon was increased, the re-absorption of bile acid did not show a significant increase (P > 0.05) as compared with other dietary lipids. Moreover, the C18:2-rich SO maintained the bile acid metabolic balance probably by decreasing the Romboutsia, while increasing the Bifidobacterium abundance in the colon. The different dietary lipids showed different effects on the bile acid metabolism, which was probably connected with the alterations in the gut microbiota structure. The present study could provide basic understandings about the influences of the different dietary lipids consumption on gut homeostasis and bile acid metabolism. © 2021 Society of Chemical Industry.

Bile acids increase intestinal marker expression via the FXR/SNAI2/miR-1 axis in the stomach

PurposeIntestinal metaplasia (IM) is a precancerous lesion that increases the risk of subsequent gastric cancer (GC) development. Previously, miR-1 has been shown to play an essential role in the initiation of bile acid (BA)-induced IM. The objective of the present study was to investigate the mechanism underlying miR-1 inhibition by BA in gastric cells.MethodsIngenuity pathway analysis (IPA) was used to identify molecules acting upstream of miR-1. The effects of deoxycholic acid (DCA), FXR and SNAI2 on the expression of intestinal markers were assessed using quantitative real-time PCR (qRT-PCR) and Western blotting. The expression level of major molecules was detected by immunohistochemistry (IHC) in tissue microarrays. The transcriptional regulation of miR-1 was verified using luciferase reporter and chromatin immunoprecipitation (ChIP) assays.ResultsWe found that BA treatment caused aberrant expression of FXR and intestinal markers in gastric cells. Augmented FXR led to transcriptional activation of SNAI2, which in turn suppressed the miR-1 promoter. Moreover, we found that compared with normal tissues, the expression levels of both FXR and SNAI2 were increased and positively correlated with each other in IM tissues. Additionally, their expression showed an inverse correlation with that of miR-1 in IM tissues.ConclusionsOur findings indicate that FXR may be responsible for a series of molecular changes in gastric cells after BA treatment, and that the FXR/SNAI2/miR-1 axis exhibits a crucial role in BA-induced progression of IM. Blocking the FXR-oriented axis may provide a promising approach for IM or even GC treatment.

Probiotics Alleviated Nonalcoholic Fatty Liver Disease in High-Fat Diet-Fed Rats via Gut Microbiota/FXR/FGF15 Signaling Pathway

Gut microbiota (GM) dysbiosis and bile acid (BA) metabolism disorder play an important role in the pathogenesis of nonalcoholic fatty liver disease (NAFLD). Probiotics had a beneficial effect on NAFLD, but further study is needed to explore probiotics as a potential therapeutic agent to NAFLD. The aim of this study was to investigate the regulatory effect of probiotics on gut microbiota in NAFLD rats and to explore the possible mechanism of probiotics regulating the bile acid receptor farnesoid X receptor/growth factor 15 (FXR/FGF15) signaling pathway in rats. We established a rat model of NAFLD fed with a high-fat diet (HFD) for 14 weeks, which was given different interventions (312 mg/kg/day probiotics or 10 mg/kg/day atorvastatin) from the 7th week. Serum lipids and total bile acids (TBA) were biochemically determined; hepatic steatosis and lipid accumulation were evaluated with HE staining. The expression levels of FXR, FGF15 mRNA, and protein in rat liver were detected. 16S rDNA was used to detect the changes of gut microbiota in rats. Compared with the HFD group, probiotics and atorvastatin significantly reduced serum lipids and TBA levels. And probiotics increased dramatically the expression of FXR, FGF15 mRNA, and protein in the liver. But there were no significant changes in the atorvastatin group. Probiotics and atorvastatin can upregulate the diversity of gut microbiota and downregulate the abundance of pathogenic bacteria in NAFLD model rats. In summary, probiotics alleviated NAFLD in HFD rats via the gut microbiota/FXR/FGF15 signaling pathway.

Checkpoint blockade combined with neoadjuvant chemotherapy (NACT) in advanced-stage epithelial ovarian cancer (EOC): preliminary results from a phase II clinical trial

<h3>Objectives:</h3> Standard of care treatment for advanced stage EOC is a combination of chemotherapy and surgery. Despite this approach, the majority of women remain incurable, underscoring the need for novel therapeutics. This study assessed the pathologic objective response rate (pORR), historically reported as 6-10% and tumor transcriptomic changes in women with advanced stage EOC treated with neoadjuvant pembrolizumab, paclitaxel, and carboplatin. <h3>Methods:</h3> This was an open-label, single-arm, phase II trial for women with newly diagnosed biopsy proven EOC dispositioned to receive carboplatin, paclitaxel and pembrolizumab 200mg/m² every 21 days. Patients received 3-4 cycles prior to interval debulking surgery followed by another 3-4 cycles of adjuvant therapy. A planned interim analysis to assess futility (based on reported historic response with NACT, required 1 pORR) was completed after enrollment of 20 of planned 40 evaluable patients. Transcriptomic analyses of bulk RNA to identify functional genes and significant pathways from matched specimens from treatment naïve tumor, and tumor after 3-4 cycles of NACT plus immune checkpoint inhibitor, (ICI) were completed. Strand-specific RNA libraries were sequenced using single-end reads (50 bp, average 40 million reads per sample) on the DNBS<i>eq platform.</i> Differentially expressed genes (DEG) with a false discovery rate q < 0.05 and a fold change of > 1.5 were used. <h3>Results:</h3> Interim data for the first 20 patients evaluable for pORR are reported. Most women were White (95%) and had high grade serous histology (100%). In 11 cases (55%), R0 (complete) cytoreduction was achieved. There have been no surgical complications related to combination treatment. Treatment was generally well tolerated, with mostly grade 1/2 toxicity: 30% pruritic rash, 10% thyroid abnormalities. One patient had grade 3 nephritis that recovered with treatment. A total of 6 patients achieved a pathologic complete response (pCR, 30%) and another 4 (25%) pathologic partial response (pPR) for a 55% pORR. There were 4 pts with deleterious genetic mutation in the homologous recombination pathway (20%) and 2 patients with Fanconi anemia somatic mutations (10%). There were 863 DEGs between the chemonaïve and ICI+NACT matched tumors. ICI+NACT induced activation of PI3K-Akt pathway, myeloid differentiation, AGE-RAGE signaling, and focal adhesion kinase pathways which included upregulation of FXR, NLRP11 and FOXL2 expression, known regulators of inflammation and immune responses. <h3>Conclusions:</h3> Interim analysis demonstrates an increase in pORR compared to previously reported in literature (6-10%) and is generally well tolerated. Transcriptomic analyses revealed specific ICI induced gene signatures when combined with NACT. Further characterization of complete and partial responders are needed to improve patient selection for ICI therapies.

The Potential Protective Role of RUNX1 in Nonalcoholic Fatty Liver Disease.

The pathogenic mechanisms underlying nonalcoholic fatty liver disease (NAFLD) are beginning to be understood. RUNX1 is involved in angiogenesis, which is crucial in inflammation, but its role in nonalcoholic steatohepatitis (NASH) remains unclear. The aim of this study was to analyze RUNX1 mRNA hepatic and jejunal abundance in women with morbid obesity (MO) and NAFLD. RUNX1, lipid metabolism-related genes, and TLRs in women with MO and normal liver (NL, n = 28), NAFLD (n = 41) (simple steatosis (SS, n = 24), or NASH (n = 17)) were analyzed by RT-qPCR. The RUNX1 hepatic expression was higher in SS than in NL or NASH, as likewise confirmed by immunohistochemistry. An increased expression of hepatic FAS was found in NAFLD. Hepatic RUNX1 correlated positively with FAS. There were no significant differences in the jejunum RUNX1 expressions in the different groups. Jejunal FXR expression was lower in NASH than in NL, while the TLR9 expression increased as NAFLD progressed. Jejunal RUNX1 correlated positively with jejunal PPARγ, TLR4, and TLR5. In summary, the hepatic expression of RUNX1 seems to be involved in the first steps of the NAFLD process; however, in NASH, it seems to be downregulated. Our findings provide important insights into the role of RUNX1 in the context of NAFLD/NASH, suggesting a protective role.

Kinsenoside Alleviates 17α-Ethinylestradiol-Induced Cholestatic Liver Injury in Rats by Inhibiting Inflammatory Responses and Regulating FXR-Mediated Bile Acid Homeostasis.

Cholestasis is an important predisposing factor of liver diseases, such as hepatocyte necrosis, liver fibrosis and primary biliary cirrhosis. In this study, we aimed to investigate the effects of Kinsenoside (KD), a natural active ingredient of Anoectochilus roxburghii, on estrogen-induced cholestatic liver injury in Sprague-Dawley rats and the underlying mechanism. The rats were randomly divided into six groups: control group, model group, low-dose KD group (50 mg/kg body weight, KD-L), medium-dose KD group (100 mg/kg body weight, KD-M), high-dose KD group (200 mg/kg body weight, KD-H) and ursodeoxycholic acid group (40 mg/kg body weight, UDCA). 17α-Ethinylestradiol (EE) was used to establish an experimental animal model of estrogen-induced cholestasis (EIC). The results demonstrated that KD alleviated liver pathologic damage, serum biochemical status and inhibited hepatocellular microstructure disorder and bile duct hyperplasia in EE-induced cholestatic rats. Mechanically, KD alleviated EE-induced cholestatic liver injury by inhibiting inflammatory responses and regulating bile acid homeostasis. Concretely, KD reduced the expression of IL-1β and IL-6 by inhibiting NF-κB p65 to suppress EE-mediated inflammation in rat liver. KD enhanced the expression of FXR and inhibited EE-mediated reduction of FXR in vitro and in vivo. It was the potential mechanism that KD mitigates cholestasis by increasing efflux and inhibiting uptake of bile acids via FXR-mediated induction of bile salt export pump (BSEP) and reduction of Na+-dependent taurocholate cotransport peptide (NTCP) to maintain bile acid homeostasis. Moreover, KD repressed the bile acid synthesis through reducing the expression of synthetic enzyme (CYP7A1), thereby normalizing the expression of metabolic enzyme (SULT2A1) of bile acid. In conclusion, our results revealed that KD may be an effective drug candidate for the treatment of cholestasis.

Bile Acids Induce IQ Containing GTPase Activating Protein 1 to Alleviate Liver Injury

Bile acids (BA) are cholesterol metabolites synthesized in the liver. In addition to their role as detergents, bile acids can function as signaling molecules via the activation of nuclear and G-protein coupled receptors, FXR and TGR5. BA signaling is associated with inflammation, cell proliferation, as well as apoptosis in the liver. Excessive accumulation of bile acids in the liver (cholestasis) is observed in many diseased states. We found that the scaffold protein IQGAP1 was induced in mouse models of cholestasis and in patients. In vitro BA treatment of liver cell-line, HepG2 also induced IQGAP1 in a dose-dependent manner. To investigate the role of this IQGAP1 induction, we fed wild-type male mice 0.1% 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) diet for 3days, 1week, and 2weeks. Serum bile acid and hepatic IQGAP1 induction increased concomitantly with time. We next treated Iqgap1-/- male mice similarly with DDC and found a 3-fold increase in serum bile acid levels compared to treated wild-type mice. Liver injury markers ALT, AST, and bilirubin were also increased. Although Iqgap1-/- mice had similar gene expression of key BA regulators, Fxr and Shp as wild-type mice, the alteration in expression of BA transporters and reduced cell-cell junction protein levels may contribute to the elevated BAs levels. We quantified gene expression of pro-inflammatory and proliferative mediators using qRT-PCR and examined the liver histology with immuno-staining. We found Iqgap1-/- livers expressed increased pro-inflammatory mediators and proliferative genes like Il-6 and cyclin D1 along with MAPK signaling targets, Fos and Egr-1. To further examine how IQGAP1 functions as a mediator of bile acid signaling, we have generated IQGAP1 domain deleted constructs and are examining their protein-protein interactions with Mass Spec. Based on our results, IQGAP1 induction subsequent to accumulation of BAs is protective against injury in the liver.

FXR Regulates Adipose Tissue Remodeling during Obesity

Obesity is a major epidemic and results in adipose tissue expansion and dysregulated glucose and lipid metabolism. Farnesoid X receptor (FXR) is a nuclear receptor expressed in many tissues that transcriptionally regulates energy homeostasis. However, the role of FXR in adipose tissue remains elusive. We identified Fxr expression in adipocytes isolated from both white (WAT) and brown (BAT) adipose tissues, and uncovered that adipocyte-specific Fxr knockout (Ad-FxrKO) mice recently generated in our laboratory exhibit adipocyte hypertrophy and concomitant reductions in lipolysis and the expression of lipolytic genes in both white and brown fat depots, which is correlated with ectopic fat accumulation in the liver and systemic glucose intolerance when challenged with a 60% high fat diet (HFD) or high fat/high sucrose western diet. Further, transcriptomic analysis of WAT from Ad-FxrKO and control mice upon chow or HFD revealed that many genes enriched in pathways associated with lipid and glucose homeostasis are misregulated in Ad-FxrKO mice with distinct patterns under normal and obese conditions. These data suggest that adipocyte-specific FXR may play a crucial role in regulating fat accumulation and the subsequent glucose homeostasis during diet-induced obesity. In addition to the energy storage and distribution properties of adipose tissue, BAT has high mitochondrial content and burns energy to produce heat and combat obesity. We found that Ad-FxrKO mice display reductions in energy expenditure and the expression of mitochondrial genes, revealing a key role of FXR in controlling BAT mitochondrial function and the consequent thermogenesis. Overall, we demonstrate that FXR can control fat breakdown and regulate mitochondrial functions in the adipose tissue, which in turn, modulates whole-body lipid and glucose metabolism.

Exploring effects of natural hyperoxic environment on liver lipid metabolism based on the bile acid-farnesoid X receptor pathway in sub-healthy rats

Objective: To investigate the effect of natural hyperoxic environment on liver lipid metabolism and liver function based on the bile acid-farnesoid X receptor pathway in sub-healthy rats. Methods: Forty adult male Wistar rats were randomly divided into control group (n = 10) and sub-healthy model group (n = 30). The control group was fed a normal diet, and the model group was fed a high-fat-sugar diet with limited daily activities for 5 weeks. The sub-healthy model was successfully established and the feeding conditions were restored. The hyperoxic intervention group (healthy group) were placed in a natural hyperoxic environment for 7 days. The rats feeding status in the spontaneous recovery group were unchanged. The appearance and exhaustive swimming time were compared before and after in healthy rats. Peripheral blood was collected for biochemical measurement. The fluorescence intensity of FXR and peroxisome proliferator activated receptor α (PPAR α) in liver tissue was detected by fluorescence double staining. Real-time fluorescent semi-quantitative PCR and Western blot were used to detect the RNA and protein expression condition of bile acid-FXR signaling pathway related indicators (FXR, PPARα, and SREBP-1c) in liver tissues. Results: Compared with the control group, the model group had gained body weight, and the vitality was decreased, while triglycerides [TG, (1.18 ± 0.20) mmol/L vs. (0.65 ± 0.12) mmol/L] and total cholesterol [TC, (1.23 ± 0.29) mmol/L vs. (1.00 ± 0.25) mmol/L] level was increased, (P < 0.05), which suggests the presence of hepatic steatosis. TG and TC level in the healthy group and spontaneous recovery group were lower than the model group, and the differences between the healthy group and the model group were statistically significant (P < 0.05). Compared with the model group, the expression of FXR and PPARα in the liver of the healthy and the spontaneous recovery group was enhanced, while the expression of the sterol regulatory element binding protein 1c (SREBP-1c) was decreased. FXR and PPARα mRNA levels in the healthy group and the model group were (9.27 ± 0.26 vs. 6.77 ± 0.20), and (9.71 ± 0.21 vs. 7.09 ± 0.24), P < 0.01, respectively. Compared with the model group, spontaneous recovery group mRNA levels were 7.99 ± 0.30 and 8.44 ± 0.28, P < 0.05, respectively. FXR and SREBP-1c protein levels between the healthy group and the model group were (1.30 ± 0.19 vs.0.43 ± 0.28), and (1.56 ± 0.22 vs. 2.43 ± 0.19), P < 0.01, respectively. Compared with the model group, the FXR and SREBP-1c protein levels of the spontaneous recovery group were 0.81 ± 0.33 vs. 2.10 ± 0.38, P < 0.05, respectively. In addition, natural hyperoxic environment had enhanced liver lipid metabolism and improved lipid disorders. Conclusion: The natural hyperoxic environment have the ability to regulate liver lipid metabolism and can improve mild hyperlipidemia to a certain extent.

Geniposide suppresses liver injury in a mouse model of DDC-induced sclerosing cholangitis.

Sclerosing cholangitis, characterized by biliary inflammation, fibrosis, and stricturing, remains one of the most challenging conditions of clinical hepatology. Geniposide (GE) has anti-inflammatory, hepatoprotective, and cholagogic effects. Whether GE provides inhibition on the development of sclerosing cholangitis is unknown. Here, we investigated the role of GE in a mouse model in which mice were fed with 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) for 4 weeks to induce sclerosing cholangitis. The results demonstrated that the increased hepatic gene expressions of pro-inflammatory (IL-6, VCAM-1, MCP-1, and F4/80) and profibrogenic markers (Col1α1, Col1α2, TGF-β, and α-SMA) in DDC feeding mice were reversed after treatment with GE. GE also suppressed expressions of CK19 and Ki67 in DDC-fed mice, suggesting that GE could ameliorate DDC-induced hepatocytes and cholangiocytes proliferation. In addition, GE significantly increased bile acids (BAs) secretion in bile, which correlated with induced expressions of hepatic FXR, BAs secretion transporters (BSEP, MRP2, MDR1, and MDR2), and reduced CYP7A1 mRNA expression. Furthermore, higher expressions of ileal FXR-FGF15 signaling and reduced ASBT were also observed after GE treatment. Taken together, these data showed that GE could modulate inflammation, fibrosis, and BAs homeostasis in DDC-fed mice, which lead to efficiently delay the progression of sclerosing cholangitis.

The effect of N-Acetyl cysteine on the expression of Fxr (Nr1h4), LXRα (Nr1h3) and Sirt1 genes, oxidative stress, and apoptosis in the liver of rats exposed to different doses of cadmium.

The aim of this study was to consider the expression of farnesoid X receptor (Fxr), liver X receptor (LXRα) and sirtuin 1 (Sirt1), oxidative stress, inflammation, apoptosis, and the protective role of N-acetylcysteine (NAC) in the liver of rats treated with cadmium (Cd). 30 Wistar rats were divided into 5 groups: G1 (control), G2 (single dose of Cd), G3 (continuous dose of Cd), G4 (single dose of Cd + continuous dose of NAC), and G5 (continuous dose of Cd + continuous dose of NAC). The apoptosis of hepatic cells was measured using the TUNEL assay. Levels of malondialdehyde (MDA), IL-10, TNF-α, and total antioxidant capacity (TAC) were measured by specific kits. The expression of Fxr, LXRα, and Sirt1 genes and ratio of Bax/Bcl2 was considered using RT-PCR. While NAC treatment improved TAC and IL-10 values, it decreased MDA and TNF-α levels in the liver of rats exposed to Cd (P < 0.001). NAC decreased Bax/Bcl2 in the liver of G4 and G5 groups (P < 0.001). Exposure to a continuous dose of Cd decreased Fxr, LXRα, and Sirt1 expression by 36.65- (P < 0.001), 12.52- (P < 0.001) and 11.34-fold (P < 0.001) compared to control, respectively. NAC increased Fxr, LXRα, and Sirt1 expression (P < 0.01) and decreased Cd concentrations in both serum and tissue samples in G4 and G5 groups. Our results suggested that NAC protects liver tissue against Cd toxicity by elevating antioxidant capacity, mitigating oxidative stress, inflammation, apoptosis and up-regulation of FXR, LXR, and SIRT1 genes.

Baitouweng Tang ameliorates DSS-induced ulcerative colitis through the regulation of the gut microbiota and bile acids via pathways involving FXR and TGR5

In China, Baitouweng Tang (BTWT) is a commonly prescribed remedy for the treatment of ulcerative colitis (UC). Herein, the present study aims to assess the anti-colitis activity of BTWT and its underlying mechanisms in UC BALB/c mice. Induction of UC in BALB/c mice was carried out by adding 3.5% DSS in the drinking water of underlined mice. After UC induction, the mice were administrated with BTWT for 7 days. Clinical symptoms were assessed, followed by analyzing the bile acids (BAs) in serum, liver, colon, bile, and feces of UC mice through UPLC-MS/MS. The modified 16S rDNA high-throughput sequencing was carried out to examine the gut microbiota of feces. BTWT significantly improved the clinical symptoms such as and histological injury and colon shortening in UC induced mice. Furthermore, BTWT remarkably ameliorated colonic inflammatory response. After BTWT treatment, the increased concentrations of UDCA, HDCA, αMCA, βMCA, CA, and GLCA in UC were decreased, and the levels of some BAs, especially CA, αMCA, and βMCA were normalized. Moreover, the relative species abundance and gut microbiota diversity in the BTWT-exposed groups were found to be considerably elevated than those in the DSS-treated group. BTWT increased the relative abundance of Firmicutes, Proteobacteria, Actinobacteria, Tenericutes, and TM7, which were statistically lower in the fecal microbiota of UC mice. The relative abundance of Bacteroidetes was found to be elevated in the DSS group and normalized after BTWT treatment. BTWT increased the expression of FXR and TGR5 in the liver. BTWT administration improved DSS-induced mice signs by increasing the TGR5 and FXR expression levels. This result was achieved by the regulation of the BAs and gut microbiota.