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Background The consumption of 2 g/d plant sterols (PS) reduces circulating low-density lipoprotein cholesterol (LDL-C) up to 10%. The degree of LDL-C lowering was associated with specific apolipoprotein E (APOE, rs429358) and cholesterol 7α-hydroxylase (CYP7A1, rs3808607) genosets in previous post hoc analyses of randomized controlled trials. However, since post-hoc analyses do not conform to the randomization model, there is a greater potential that the findings may be due to type I error, thus warranting validation through an a priori-designed intervention trial. Objective The GenePredict Plant Sterol study (GPS) was designed to validate associations of LDL-C lowering with specific APOE and CYP7A1 genosets through a priori recruitment of individuals carrying pre-specified genosets. Methods A two center, double-blind, placebo-controlled, randomized two-period crossover dietary intervention with 2 g/d of PS for 28 days with a minimum 28 day washout was undertaken from July 2017 to December 2019. A priori recruitment of individuals with slightly elevated LDL-C was based on genosets of APOE isoforms and CYP7A1 rs3808607. Randomization was performed with stratification by sex and genoset. Results The recruitment target of 64 participants with pre-specified genosets could not be reached, despite the screening of 477 individuals; 42 participants completed the intervention trial. Reductions in LDL-C were similar across all three genosets (-0.298 ±0.164, -0.357 ±0.115, -0.293 ±0.109 mmol/L, P = 0.0002 overall, P = 0.9126 for treatment*genoset), providing evidence that the shortfall in recruitment may not have stopped the trial from meeting the objective. Conclusions APOE and CYP7A1 genotypes did not influence the efficacy of LDL-C reductions upon dietary intervention with PS. Findings of previous post-hoc analyses could not be validated in a trial using a priori genotype-based recruitment. Obtaining adequate numbers of participants is challenging in trials using genoset-based recruitment, even for common variants.Trial Registration: Clinical Trials #NCT02765516 https://clinicaltrials.gov/ct2/show/NCT02765516.

The potential toxicity of carbon quantum dots (CQDs) has received much attention because of their increasing biomedical applications. However, the impacts of CQDs on the gut–liver axis and gut microbiota of the host remain unclear. In this study, we investigated the effects of CQD chronic exposure (5 weeks) on the biodistribution, histopathology, antioxidant capacity, immune response, lipid metabolism, and gut microbiota composition in the common carp Cyprinus carpio at different concentrations (2 and 20 mg kg−1 body weight). The results demonstrated that CQDs heavily accumulated in the intestine and liver, severely damaging these organs. Superoxide dismutase and glutathione were reduced and malondialdehyde was increased in intestinal and liver tissues, and the nrf2/ho-1 signaling pathway was downregulated. In addition, CQDs activated toll-like receptor pathways to mediate inflammatory responses. Serum lipid levels were altered after CQD exposure, and srebp-1c, fas, hmgcr, and fxr expression was upregulated and cyp7a1 and cyp27a1 expression was downregulated in the intestine and liver. Interestingly, mttp and cpt-1α expression was upregulated and abca1, abcg8, and fgf19 expression was downregulated in the intestine, whereas their expression was opposite in the liver. Finally, 16S rRNA sequence analysis showed that gut microbiota diversity and richness were reduced, and the relative abundance of harmful bacteria increased and that of beneficial bacteria decreased. Bioinformatic analysis showed that the antioxidant capacity, immune response, and lipid metabolism also correlated with the relative abundance of gut microbial genera. In summary, this study provides reliable data for toxicological risk assessment of CQDs in aquatic ecosystems.

Bile acid metabolism is altered in neonates on parenteral nutrition (PN), predisposing them to parenteral nutrition-associated liver disease. Cholesterol 7α-hydroxylase (CYP7A1), the rate-limiting enzyme in the bile acid synthesis pathway, is repressed by fibroblast growth factor 19 (FGF19) and phytosterols (PS). We describe a case of a preterm infant who developed necrotizing enterocolitis (NEC) and received exclusive PN for over 2 months. Our objective was to serially assess CYP7A1 activity and plasma FGF19 and PS concentrations in this infant case compared to five healthy preterm infants. We found that CYP7A1 activity increased during the first 2 weeks of life in control infants but was undetectable in the infant case. FGF19 concentrations were high at birth in all infants and subsequently declined and did not differ between the case and control infants. As expected, PS concentrations were elevated in the infant case and continued to increase despite lipid minimization. In conclusion, CYP7A1 activity was gradually upregulated in healthy preterm infants but remained suppressed in the infant requiring prolonged PN. Preterm infants also had elevated FGF19 concentrations at birth, which decreased with advancing postnatal age.

Bile acids (BAs) are amphipathic molecules important for metabolism of cholesterol, absorption of lipids and lipid soluble vitamins, bile flow, and regulation of gut microbiome. There are over 30 different BA species known to exist in humans and mice, which are endogenous modulators of at least 6 different membrane or nuclear receptors. This diversity of ligands and receptors play important roles in health and disease; however, the full functions of each individual BA in vivo remain unclear. We generated a mouse model lacking the initiating enzymes, CYP7A1 and CYP27A1, in the two main pathways of BA synthesis. Because females are more susceptible to BA related diseases, such as intrahepatic cholestasis of pregnancy, we expanded this model into female mice. The null mice of Cyp7a1 and Cyp27a1 were crossbred to create double knockout (DKO) mice. BA concentrations in female DKO mice had reductions in serum (63%), liver (83%), gallbladder (94%), and small intestine (85%), as compared to WT mice. Despite low BA levels, DKO mice had a similar expression pattern to that of WT mice for genes involved in BA regulation, synthesis, conjugation, and transport. Additionally, through treatment with a synthetic FXR agonist, GW4064, female DKO mice responded to FXR activation similarly to WT mice., Graphical abstract A mouse model lacking the initiating enzymes, CYP7A1 and CYP27A1, in the two main pathways of BA synthesis was generated.Image 1

Emerging evidence links dietary fiber with altered gut microbiota composition and bile acid signaling in maintaining metabolic health. Yeast β-glucan (Y-BG) is a dietary supplement known for its immunomodulatory effect, yet its impact on the gut microbiota and bile acid composition remains unclear. This study investigated whether dietary forms of Y-BG modulate these gut-derived signals. We performed 4-week dietary supplementation in healthy mice to evaluate effects of different fiber composition (soluble vs particulate Y-BG) and dose (0.1 vs. 2%). We found that 2% particulate Y-BG induced robust gut microbiota community shifts with elevated liver Cyp7a1 mRNA abundance and bile acid synthesis. These diet-induced responses were notably different when compared to the prebiotic inulin, and included a marked reduction in fecal Bilophila abundance which we demonstrated as translatable to obesity in population-scale American Gut and TwinsUK clinical cohorts. This prompted us to test whether 2% Y-BG maintained metabolic health in mice fed 60% HFD over 13 weeks. Y-BG consistently altered the gut microbiota composition and reduced Bilophila abundance, with trends observed in improvement of metabolic phenotype. Notably, Y-BG improved insulin sensitization and this was associated with enhanced ileal Glpr1r mRNA accumulation and reduced Bilophila abundance. Collectively, our results demonstrate that Y-BG modulates gut microbiota community composition and bile acid signaling, but the dietary regime needs to be optimized to facilitate clinical improvement in metabolic phenotype in an aggressive high-fat diet animal model.

Objectives Increased cholesterol levels were found to be associated with diabetes mellitus type II (DM2). The cholesterol is metabolized by cytochrome 7A1 (CYP7A1) and transported in the intestine by ATP-binding cassette G8 (ABCG8). Genetic variants in CYP7A1 and ABCG8 genes can affect the cholesterol levels. The aim of this study is to compare the frequency of CYP7A1 rs3808607 and ABCG8 rs11887534 and rs4148217 genotypes between healthy and DM2 subjects from Jordanian population. Methods A total of 117 DM2 patients and 100 healthy controls, of Jordanian Arabic origin, were genotyped for CYP7A1 rs3808607 and ABCG8 rs11887534 and rs4148217 genetic variants using polymerase chain reaction (PCR) followed by restriction fragment length polymorphism technique. Results The study showed that homozygosity of rs3808607 (A-204C) genotype in CYP7A1 was significantly higher in DM2 patients (ANOVA, prs11887534 (G55C) and rs4148217 (C1199A) genetic polymorphisms in ABCG8 were found in comparable frequencies in both healthy and DM2 subjects. Conclusions The results of this study indicate that CYP7A1 rs3808607 genetic polymorphism is associated with DM2. Further clinical studies are required to confirm this finding among DM2 patients of Jordanian origin.

Drug-induced liver injury (DILI) is the leading cause of acute liver failure and a major concern in drug development. Altered bile acid homeostasis via inhibition of the bile salt export pump (BSEP) is one mechanism of DILI. Dasatinib, pazopanib, and sorafenib are tyrosine kinase inhibitors (TKIs) that competitively inhibit BSEP and increase serum biomarkers for hepatotoxicity in ∼25–50% of patients. However, the mechanism(s) of hepatotoxicity beyond competitive inhibition of BSEP are poorly understood. This study examined mechanisms of TKI-mediated hepatotoxicity associated with altered bile acid homeostasis. Dasatinib, pazopanib, and sorafenib showed bile acid-dependent toxicity at clinically relevant concentrations, based on the C-DILI assay using sandwich-cultured human hepatocytes (SCHH). Among several bile acid-relevant genes, cytochrome P450 (CYP) 7A1 mRNA was specifically upregulated by 6.2- to 7.8-fold (dasatinib) and 5.7- to 9.3-fold (pazopanib), compared with control, within 8 hours. This was consistent with increased total bile acid concentrations in culture medium up to 2.3-fold, and in SCHH up to 1.4-fold, compared with control, within 24 hours. Additionally, protein abundance of sodium taurocholate co-transporting polypeptide (NTCP) was increased up to 2.0-fold by these three TKIs. The increase in NTCP protein abundance correlated with increased function; dasatinib and pazopanib increased hepatocyte uptake clearance (CL(uptake)) of taurocholic acid, a probe bile acid substrate, up to 1.4-fold. In conclusion, upregulation of CYP7A1 and NTCP in SCHH constitute novel mechanisms of TKI-associated hepatotoxicity. SIGNIFICANCE STATEMENT: Understanding the mechanisms of hepatotoxicity associated with tyrosine kinase inhibitors (TKIs) is fundamental to development of effective and safe intervention therapies for various cancers. Data generated in sandwich-cultured human hepatocytes, an in vitro model of drug-induced hepatotoxicity, revealed that TKIs upregulate bile acid synthesis and alter bile acid uptake and excretion. These findings provide novel insights into additional mechanisms of bile acid-mediated drug-induced liver injury, an adverse effect that limits the use and effectiveness of TKI treatment in some cancer patients.

Policosanol exhibits a lipid accumulation alleviating effect, but the underlying mechanisms remains unclear. Bile acids are a significant factor in regulating cholesterol and lipid metabolism homeostasis in mammals. This study was aimed to elucidate the alleviating effect and underlying mechanisms of policosanol on hepatic lipid accumulation through bile acid (BA) metabolism. Policosanol supplementation significantly reduced hepatic triglycerides (19.29%), cholesterol (30.38%) in high fat diet (HFD) induced obese mice (P < 0.05). Furthermore, compared with the control group, HFD decreased the levels of total BAs (TBAs, 37.67%) and cholic acid (CA, 62.74%) in the serum of mice (P < 0.05). Meanwhile, compared to HFD group, policosanol also increased the level of secondary BAs (SBAs) and muricholic acids (MCAs, P < 0.05). qRT-PCR combined with protein level analysis revealed that policosanol significantly decreased sterol regulatory element-binding protein (SREBP-1c) and CD36, and increased the expression level of cytochrome P450 family 7 subfamily A member 1 (CYP7A1) and cytochrome P450 Family 27 Subfamily A Member 1 (CYP27A1, P < 0.05). Additionally, in the liver, policosanol was found downregulated the expression of farnesoid X receptor (FXR)-small heterodimer partner (SHP), and activate the Takeda G-coupled protein receptor 5 (TGR5)-adenosine-monophosphate-activated protein kinase (APMK) signaling pathway (P < 0.05). Peroxisome proliferator activated receptor (PPAR)-α, hormone sensitive lipase (HSL), and carnitine palmitoyltransferase (CPT)-1α also significantly increased in HP group (P < 0.05). The aforementioned results reveal that the potential mechanism of policosanol in alleviating liver lipid accumulation is to promote BA synthesis and lipolysis through regulating the cross-talk of the AMPK-FXR-TGR5. New insight for the application of policosanol as an anti-fatty liver functional food ingredient or supplement is also provided. PRACTICAL APPLICATION: Policosanol is an important active component of cereals and insect waxes (15-80%). However, almost no policosanol in refined foods such as clear corn germ oil and wheat flour. This study showed that oral administration of policosanol can significantly reduce triglyceride and cholesterol levels in the liver through affecting AMPK-TGR5-FXR cross-talk, whereas no significant toxicological effect is reported in human and mouse models. This study may provide theoretical support for the theory of dietary structure and the development of dietary supplements to improve lipid metabolism targeting the "bile acid-AMPK-TGR5" pathway.

Liver fibrosis plays a critical role in liver disease progression. A sialoglycopeptide from the Gadus morhua eggs (Gm-SGPP) was identified having a 7000 Da molecular weight with a core pentasaccharide structure and osteogenesis activity. However, whether Gm-SGPP is beneficial to liver fibrosis remains unknown. In this study, mice with liver fibrosis were intraperitoneally injected with 2.5% CCl4 (10 mL/kg) and orally administered with Gm-SGPP (500 mg/kg) for 30 days. Results showed that Gm-SGPP alleviated oxidative liver damage and lipid metabolism disorder and reduced hepatocyte necrosis and lipid droplet accumulation. Notably, we found that Gm-SGPP increased the number and changed the composition of bile acids via increasing cholesterol 7a-hydroxylase (CYP7A1) and sterol 27-hydroxylase (CYP27A1) expression, which caused inhibition of ileum farnesoid X receptor (FXR) expression and accelerated the cholesterol conversion. Cholesterol accumulation is a risk factor for liver fibrosis. Masson staining showed that Gm-SGPP significantly reduced the degree of collagen deposition. Western blotting further suggested that Gm-SGPP downregulated the key gene of the toll-like receptor 4 (TLR4)-mediated transforming growth factor-β (TGF-β)/Smad pathway. To our best knowledge, this is the first report that Gm-SGPP prevented liver fibrosis via attenuating cholesterol accumulation. Our present results provide new ideas for the Gadus morhua egg's high-value utilization.

Hypercholesterolemia is the main cause of cardiovascular disease worldwide, and the regulation of cholesterol homeostasis is essential for human health. Lactobacillus is present in large quantities in the human intestine. As the normal flora in the gut, lactobacillus plays an important role in regulating metabolism in the human body. Lactobacillus can regulate the cholesterol content by regulating the expression of genes involved in cholesterol synthesis, metabolism, and absorption. This article reviews the biological effects and mechanisms of lactobacillus that mediate the expression of NPC1L1, CYP7A1, ABCG5, ABCG8, and other genes to inhibit cholesterol absorption, and discusses the mechanism of reducing cholesterol by lactobacillus in cells in vitro, to provide a theoretical basis for the development and utilization of lactobacillus resources.

A herbal prescription in traditional Chinese medicine (TCM) has great complexity, with multiple components and multiple targets, making it extremely challenging to determine its bioactive compounds. Yinchenhao Tang (YCHT) has been extensively used for the treatment of jaundice disease. Although many studies have examined the efficacy and active ingredients of YCHT, there is still a lack of an in-depth systematic analysis of its effective components, mechanisms, and potential targets—especially one based on clinical patients. This study established an innovative strategy for discovering the potential targets and active compounds of YCHT based on an integrated clinical and animal experiment platform. The serum metabolic profiles and constituents of YCHT in vivo were determined by ultra-performance liquid chromatography–quadrupole time-of-flight mass spectrometry (UPLC-Q-ToF-MS)-based metabolomics combined with a serum pharmacochemistry method. Moreover, a compound–target–pathway network was constructed and analyzed by network pharmacology and ingenuity pathway analysis (IPA). We found that eight active components could modulate five key targets. These key targets were further verified by enzyme-linked immunosorbent assay (ELISA), which indicated that YCHT exerts therapeutic effects by targeting cholesterol 7α-hydroxylase (CYP7A1), multidrug-resistance-associated protein 2 (ABCC2), multidrug-resistance-associated protein 3 (ABCC3), uridine diphosphate glucuronosyl transferase 1A1 (UGT1A1), and farnesoid X receptor (FXR), and by regulating metabolic pathways including primary bile acid biosynthesis, porphyrin and chlorophyll metabolism, and biliary secretion. Eight main effective compounds were discovered and correlated with the key targets and pathways. In this way, we demonstrate that this integrated strategy can be successfully applied for the effective discovery of the active compounds and therapeutic targets of an herbal prescription.

BACKGROUND AND AIMS: Chronically administered parenteral nutrition (PN) in patients with intestinal failure carries the risk for developing PN-associated cholestasis (PNAC). We have demonstrated that farnesoid X receptor (FXR) and liver X receptor (LXR), proinflammatory interleukin-1 beta (IL-1β), and infused phytosterols are important in murine PNAC pathogenesis. In this study we examined the role of nuclear receptor liver receptor homolog 1 (LRH-1) and phytosterols in PNAC. APPROACH AND RESULTS: In a C57BL/6 PNAC mouse model (dextran sulfate sodium [DSS] pretreatment followed by 14 days of PN; DSS-PN), hepatic nuclear receptor subfamily 5, group A, member 2/LRH-1 mRNA, LRH-1 protein expression, and binding of LRH-1 at the Abcg5/8 and Cyp7a1 promoter was reduced. Interleukin-1 receptor–deficient mice (Il-1r(−/−)/DSS-PN) were protected from PNAC and had significantly increased hepatic mRNA and protein expression of LRH-1. NF-κB activation and binding to the LRH-1 promoter were increased in DSS-PN PNAC mice and normalized in Il-1r(−/−)/DSS-PN mice. Knockdown of NF-κB in IL-1β–exposed HepG2 cells increased expression of LRH-1 and ABCG5. Treatment of HepG2 cells and primary mouse hepatocytes with an LRH-1 inverse agonist, ML179, significantly reduced mRNA expression of FXR targets ATP binding cassette sub-family C member 2/multidrug resistance associated protein 2 (ABCC2/MRP2), nuclear receptor subfamily 0, groupB, member 2/small heterodimer partner (NR0B2/SHP), and ATP binding cassette subfamily B member 11/bile salt export pump (ABCB11/BSEP). Co-incubation with phytosterols further reduced expression of these genes. Similar results were obtained by suppressing the LRH-1 targets ABCG5/8 by treatment with small interfering RNA, IL-1β, or LXR antagonist GSK2033. Liquid chromatography–mass spectrometry and chromatin immunoprecipitation experiments in HepG2 cells showed that ATP binding cassette subfamily G member 5/8 (ABCG5/8) suppression by GSK2033 increased the accumulation of phytosterols and reduced binding of FXR to the SHP promoter. Finally, treatment with LRH-1 agonist, dilauroyl phosphatidylcholine (DLPC) protected DSS-PN mice from PNAC. CONCLUSIONS: This study suggests that NF-κB regulation of LRH-1 and downstream genes may affect phytosterol-mediated antagonism of FXR signaling in the pathogenesis of PNAC. LRH-1 could be a potential therapeutic target for PNAC. (Hepatology 2021;0:1–17).

ι-Carrageenan tetrasaccharide (ιCTs), a novel oligosaccharide, was hydrolyzed from ι-carrageenan with targeting marine tool-enzyme Cgi82A. Previously, we have found ιCTs exhibited a hypoglycemic effect, whether it could regulate lipid metabolism remains unknown. In this study, the insulin-resistant mice induced by high-fat-high-sucrose diet were orally administrated with ιCTs (30 mg/kg·bw) for 20 weeks. The results showed that the contents of triglyceride and cholesterol in both serum and liver were reduced by ιCTs, and their excretion in feces were promoted, suggesting lipid accumulation was inhibited. Intriguingly, the overall levels of bile acid in serum, liver, and feces were all raised by ιCTs. Given that bile acids are the essential signal factors for regulating lipid metabolism via the farnesoid-X-receptor (FXR), we conducted serum bile acid profile analysis and found that the levels of high-affinity agonists deoxycholic acid and lithocholic acid were decreased in the ιCTs group, showing that ιCTs failed to activate FXR. Western blot analysis showed that ιCTs downregulated hepatic FXR and small heterodimer partner (SHP) expression and increased downstream CYP7A1 expression via regulating the FXR-SHP signal to accelerate liver cholesterol conversion. Meanwhile, ιCTs decreased the expression of PXR and SREBP1c and elevated the expression of PPARα and CPT1α via regulating the FXR-PXR-SREBP1c/PPARα signal to inhibit fatty acid synthesis and promote fatty acid β-oxidation. To the best of our knowledge, this study for the first time reported that ιCTs alleviated liver lipid accumulation via the bile acid-FXR-SHP/PXR signal to regulate cholesterol conversion and fatty acid metabolism, which highlighted a new idea for ameliorating insulin resistance.

Hyperlipidemia an immense group of acquired or genetic metabolic disorders that is characterized by an excess of lipids in the bloodstream. Altogether, they have a high prevalence worldwide and constitute a major threat to human health. Glycosaminoglycans (GAG) are natural biomolecules that have hypolipidemic activity. The purpose of this study was to investigate the potential hypolipidemic effect of glycosaminoglycans extracted from Ostrea rivularis (OGAG) on hyperlipidemic zebrafish, as well as the possible underlying mechanism of such effect. Dietary supplementation with OGAG during 4 weeks significantly reduced the serum and hepatic lipid levels and the hepatosomatic index in hyperlipidemic zebrafish. In addition, histopathological showed that OGAG supplementation decreases the volume and number of lipid droplets in hepatocytes. Transcriptome and real‐time quantitative polymerase chain reaction analysis revealed that the gene expression levels of PPARγ, SCD, HMGRA, ACAT2, HMGCS, and HMGCR were significantly downregulated by OGAG treatment in hepatocytes, whereas those of CD36, FABP2, FABP6, ABCG5, and CYP7A1 were significantly upregulated. This suggests that the hypolipidemic effect of OGAG relies on increasing the ketogenic metabolism of fatty acids, inhibiting cholesterol synthesis, and enhancing the transformation of cholesterol to bile acid. Furthermore, OGAG treatment improved gut microbiota imbalance by reducing the Firmicutes‐to‐Bacteroidetes ratio, increasing the relative abundance of beneficial bacteria (Bacteroidetes, Verrucomicrobia, Acidobacteria, and Sphingomonas), and reducing the relative abundance of harmful bacteria (Proteobacteria, Cohaesibacter, Vibrio, and Terrisporobacter). These findings highlight the potential benefit of implementing OGAG as a dietary supplement to prevent and treat hyperlipidemia.

Hypercholesterolemia is a major risk factor for chronic metabolic diseases. Nevertheless, a whole-grain diet could ameliorate this issue in a number of ways, including by regulating bile acid metabolism. However, the potential mechanism is unclear. The aim of the current study is to explore the effects of whole-grain diets (brown rice diet and whole wheat diet) on bile acid homeostasis. After intervention for 8 weeks in mouse model, whole-grain diets showed reduced feed conversion ratio, and the lipid levels (total cholesterol (TC) and triglycerides (TG)) were also meliorated in the serum and liver of mice. Moreover, whole-grain diets reduced the expression of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) (cholesterol synthesis) in the liver of mice. Interestingly, whole-grain diets not only promoted the mRNA expressions of low-density lipoprotein receptor (LDLR), ATP binding cassette transporter G1 (ABCG1), and scavenger receptor class B type I (SR-BI) (reverse cholesterol transport) but also facilitated the expressions of cytochrome P450, family 7, subfamily a, polypeptide 1 (CYP7a1) and cytochrome P450, family 27, subfamily a, polypeptide 1 (CYP27a1) (bile acid synthesis). Further study found that whole-grain diets promoted intestinal bile acid reabsorption and reduced bile acid excretion. Our study provided a novel metabolic regulation of bile acids in response to reduced cholesterol levels induced by whole-grain diets.

A high-fat diet (HFD) causes hyperlipidemia, which worsens disturbances in bile acid (BA) metabolism and gut microbiota. This study aimed to investigate the regulation of flavonoids from whole-grain oat (FO) on BA metabolism and gut microbiota in HFD-induced hyperlipidemic mice. The experiment results showed that FO improved serum lipid profiles and decreased body weight and lipid deposition in HFD-fed mice. Through real-time qualitative polymerase chain reaction (RT-qPCR) and Western blot assays, by up-regulating the expression of PPARα, CPT-1, CYP7A1, FXR, TGR5, NTCP, and BSTP, and down-regulating those of SREBP-1c, FAS, and ASBT, FO suppressed lipogenesis, promoted lipolysis and BA synthesis, and efflux to faeces via the FXR pathway. 16s rRNA sequencing revealed that FO significantly increased Akkermansia and significantly decreased Lachnoclostridium, Blautia, Colidextribacter, and Desulfovibrio. Spearman's correlation analysis showed that these bacteria were strongly correlated with hyperlipidemia-related parameters. Therefore, our results indicated that FO possessed an antihyperlipidemic effect via regulating the gut-liver axis, i.e., BA metabolism and gut microbiota.

Our previous study showed that apple polyphenol extract (APE) ameliorated high-fat diet-induced hepatic steatosis in C57BL/6 mice by targeting the LKB1/AMPK pathway; to investigate whether other mechanisms are involved in APE induction of improved hepatic steatosis, especially the roles of bile acid (BA) metabolism and gut microbiota, we conducted this study. Thirty-three C57BL/6 male mice were fed with high-fat diet for 12 weeks and concomitantly treated with sterilized water (CON) or 125 or 500 mg/(kg·bw·day) APE (low-dose APE, LAP; high-dose APE, HAP) by intragastric administration. APE treatment decreased total fecal BA contents, especially fecal primary BA levels, mainly including cholic acid, chenodeoxycholic acid, and muricholic acid. An upregulated hepatic Farnesoid X receptor (FXR) protein level and downregulated protein levels of cholesterol 7α-hydroxylase (CYP7A1) and cholesterol 7α-hydroxylase (CYP27A1) were observed after APE treatment, which resulted in the suppressed BA synthesis. Meanwhile, APE had no significant effects on mucosal injury and FXR expression in the jejunum. APE regulated the diversity of gut microbiota and microbiota composition, characterized by significantly increased relative abundance of Akkermansia and decreased relative abundance of Lactobacillus. Furthermore, APE might affect the reverse cholesterol transport in the ileum, evidenced by the changed mRNA levels of NPC1-like intracellular cholesterol transporter 1 (Npc1l1), liver X receptor (Lxr), ATP binding cassette subfamily A member 1 (Abca1), and ATP binding cassette subfamily G member 1 (Abcg1). However, APE did not affect the dihydroxylation and taurine metabolism of BA. The correlation analysis deduced no obvious interactions between BA and gut microbiota. In summary, APE, especially a high dose of APE, could alleviate hepatic steatosis, and the mechanisms were associated with inhibiting BA synthesis and modulating gut microbiota.

BACKGROUND Rice α-globulin has been reported to have serum cholesterol-lowering activity in rats. However, it is still unclear whether α-globulin exerts this effect when taken as one of the dietary components. In the present study, we investigated the effect of two cultivars of rice, low glutelin content (LGC)-1 and LGC-Jun, on reducing serum cholesterol in exogenously hypercholesterolemic (ExHC) rats. LGC-1 is enriched in α-globulin (10.6 mg g-1 rice flour, which is an approximately 1.5 times higher α-globulin content than in Koshihikari a predominant rice cultivar in Japan), whereas LGC-Jun is a globulin-negative cultivar. METHODS ExHC rats, the model strain of diet-induced hypercholesterolemia, were fed 50% LGC-1 or LGC-Jun and 0.5% cholesterol-containing diets for 2 weeks, followed by measurement of cholesterol metabolism parameters in serum and tissues. RESULTS Serum cholesterol and non-high-density lipoprotein cholesterol levels were significantly lower in the LGC-1 group compared to the LGC-Jun group. Cholesterol intestinal absorption markers, hepatic and serum levels of campesterol and β-sitosterol, and lymphatic cholesterol transport were not different between the two groups. Levels of 7α-hydroxycholesterol, an intermediate of bile acid synthesis, showed a downward trend in the livers of rats that were fed LGC-1 (P = 0.098). There was a significant decrease in the hepatic mRNA expression of Cyp7a1 (a synthetic enzyme for 7α-hydroxycholesterol) in the LGC-1 group compared to the LGC-Jun group. CONCLUSION Dietary LGC-1 significantly decreased serum cholesterol levels in ExHC rats. The possible mechanism for the cholesterol-lowering activity of LGC-1 is partial inhibition of bile acid and cholesterol synthesis in the liver. © 2021 Society of Chemical Industry.

Nickel oxide nanoparticles (Nano NiO) evoke hepatotoxicity, while whether it affects the hepatic metabolism remains unclear. The aim of this study was to explore the differential metabolites and their metabolic pathways in rat serum and to further verify the potential mechanism of bile acids’ (BAs) metabolism dysregulation after Nano NiO exposure. Sixteen male Wistar rats were intratracheally instilled with Nano NiO (0.24 mg/kg body weight) twice a week for 9 weeks. Liquid chromatography/mass spectrometry was applied to filter the differentially expressed metabolites in rat serum. Western blot was employed to detect the protein contents. Twenty-one differential metabolites that associated with BAs, lipid and phospholipid metabolism pathways were identified in rat serum after Nano NiO exposure. Decreased cholic acid and deoxycholic acid implied that the BAs metabolism was disturbed. The nickel content increased in liver after Nano NiO exposure. The protein expression of cholesterol 7α-hydroxylase (CYP7A1) was down-regulated, and the bile salt export pump was up-regulated after Nano NiO administration in rat liver. Moreover, dehydroepiandrosterone sulphotransferase (SULT2A1) and cytochrome P450 (CYP) 3A4 were elevated in the exposure group. In conclusion, Nano NiO might trigger the disturbances of BAs, lipid and phospholipid metabolism pathways in rats. The diminished serum BAs induced by Nano NiO might be related to the down-regulation of synthetase and to the overexpression of transmembrane protein and detoxification enzymes in BAs metabolism.

Liraglutide is an analogue of human glucagon-like peptide-1 (GLP-1), an endogenous intestinal hormone which play essential roles in the regulation of glycolipid metabolism. To investigate the role of lactic acid bacteria (LAB) in the lipid-lowering effect of liraglutide, forty mice were divided into normal saline-treated basal diet (NFD), normal saline-treated high-fat food (HFD), 10.0 mg/kg/d simvastatin-treated HFD (SIM + HFD), 200 and 400 μg/kg/d liraglutide-treated HFD (LL + HFD and HL + HFD) groups for 5 weeks. 16S rDNA sequencing, real-time quantitative PCR and western blot were used to detected changes of intestinal flora, cholesterol 7α-hydroxylase (CYP7A1), LDL-receptor (LDLR) and 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR). Results showed that liraglutide could up-regulate CYP7A1 and LDLR, whereas down-regulate HMGCR. Besides, liraglutide enhance the abundance of lactobacillaceae in gut of hyperlipidemic mice and increase the bile tolerance ability of LAB by up-regulating bile salt hydrolases, and the lysate of liraglutide-sensitive LAB could also directly down-regulate HMGCR, the key enzyme in cholesterol synthesis, and inhibit hepatocyte steatosis. These findings might provide new theoretical guidance for clinical application of liraglutide and threw a light on research and development of anti-obesity, hypolipidemic and cholesterol-lowering drugs or functional foods.

Backgrounds/aims PPARγ, farnesoid X receptor (FXR) and CYP7A1 are associated with solubility of bile. This study was performed to understand a mechanism and interactions of statin-induced PPARγ, PGC-1α and HNF-4α related to the statin-induced activation of FXR and CYP7A1, and verify whether the mevalonate pathway is involved in the mechanism. Methods MTT assays were performed using cultured human Hep3B cells to determine the effect of atorvastatin on the cell proliferation. Expression levels of indicated proteins were measured using Western blotting assays by inhibiting the protein expression or not. Results Atorvastatin increased expression of PPARγ, PGC-1α, HNF-4α, FXR, and CYP7A1 in Hep3B cells. PPARγ ligand of troglitazone upregulated the expression of PGC-1α, HNF-4α, FXR, and CYP7A1 in Hep3B cells. Silencing of PPARγ, PGC1α, and HNF4α using respective siRNA demonstrated that atorvastatin-induced FXR and CYP7A1 activation required sequential action of PPARγ /PGC-1α/HNF-4α. The silencing of PPARγ completely inhibited atorvastatin-induced PGC-1α expression, and the PGC1α silencing partially inhibited atorvastatin-induced PPARγ expression. The inhibition of HNF4α did not affect atorvastatin-induced PPARγ expression, but partially inhibited atorvastatin-induced PGC-1α expression. Besides, mevalonate completely reversed the effect of atorvastatin on PPARγ, PGC-1α, HNF-4α, FXR, and CYP7A1. Conclusions Atorvastatin induces FXR and CYP7A1 activation as a result of sequential action of PPARγ/PGC-1α/HNF-4α in human hepatocytes. We propose that atorvastatin enhances solubility of cholesterol in bile by simultaneously activating of FXR and CYP7A1.

Non-alcoholic fatty liver disease (NAFLD) is a spectrum of liver disease that is becoming more prevalent in concert with obesity and poor lifestyle habits. Although NAFLD is treatable via lifestyle modification in early stages, more advanced liver pathologies (eg non-alcoholic steatohepatitis [NASH]) are harder to reverse. There is no Food and Drug Administration approved pharmacological treatment for NAFLD, and little research has been done to identify compounds that target key NAFLD mechanisms. Bile acids and bile acid receptors have been implicated in NAFLD pathogenesis and modulating bile acids and bile acid receptors has recently been targeted as a therapeutic treatment option for NAFLD. Fibroblast growth factor 19 (FGF19), a nutritionally regulated post-prandial hormone, is a chief regulator of bile acid metabolism and an important player in lipid and carbohydrate metabolism, including key mechanisms of NAFLD pathogenesis. In this review, we discuss recent findings related to FGF19-regulated processes involved in the pathogenesis of NAFLD. We summarize known and conjectural frameworks and limitations for the clinical application of FGF19-targeted therapies as they relate to NAFLD.

Estrogen depletion in postmenopausal women and animal models of ovariectomy is associated with some undesirable alternations in lipid metabolism, the adverse impacts of which could be improved through regular exercise training; however, molecular mechanisms underlying this process are not fully understood. In this study, the impacts of an 8-week moderate aerobic exercise training on plasma lipid profile, liver enzymes, and some gene expression involved in cholesterol metabolism were investigated in ovariectomized rats. Forty female Wistar rats were randomly divided into four groups including sham-control, exercise training, ovariectomized-control (OVX), and ovariectomized + Exercise training (OVX + E). Three weeks after ovariectomy, the animals began their training on the treadmill (25 m/min, 5 sessions/week) for 8 weeks. The hepatic expression of Fansoid X receptor (FXR), Cholesterol-1-alphahydroxylase 1 (CYP7A1), and Small heterodimeric protein (SHP) along with lipid profile and liver enzymes were assessed. The hepatic expression of FXR, CYP7A1 and SHP genes were down-regulated in OVX rats compared to the exercise group. The levels of triglyceride (TG) and total cholesterol (TC) were significantly increased in OVX and OVX + E rats in comparison to sham and exercise groups. The levels of liver enzymes were also increased in OVX rats. However, exercise did not alter liver enzymes, despite a decrease in total cholesterol in OVX rats. Although ovariectomy could down-regulate the hepatic gene expressions involved in cholesterol metabolism, our exercise protocol could not alter the expression of these genes in OVX rats. These effects may occur due to other variables such as some regulatory mechanisms which are not the subject of the present research.

Atherosclerosis is the leading cause of cardiovascular diseases worldwide. Trimethylamine N-oxide (TMAO), a metabolite of intestinal flora from dietary quaternary amines, has been shown to be closely related to the development of atherosclerosis. Previous studies have shown that Enterobacter aerogenes ZDY01 significantly reduces the serum levels of TMAO and cecal trimethylamine (TMA) in Balb/c mice; however, its role in the inhibition of choline-induced atherosclerosis in ApoE-/- mice remains unclear. Here, we demonstrated that E. aerogenes ZDY01 inhibited choline-induced atherosclerosis in ApoE-/- mice fed with 1.3% choline by reducing cecal TMA and modulating CDCA-FXR/FGF15 axis. We observed that E. aerogenes ZDY01 decreased the cecal TMA and serum TMAO levels by utilizing cecal TMA as a nutrient, not by changing the expression of hepatic FMO3 and the composition of gut microbiota. Furthermore, E. aerogenes ZDY01 enhanced the expression of bile acid transporters and reduced the cecal CDCA levels, thereby attenuating the FXR/FGF15 pathway, upregulating the expression of Cyp7a1, promoting reverse cholesterol transport. Taken together, E. aerogenes ZDY01 attenuated choline-induced atherosclerosis in ApoE-/- mice by decreasing cecal TMA and promoting reverse cholesterol transport, implying that E. aerogenes ZDY01 treatment might have therapeutic potential in atherosclerosis.

Farnesoid X receptor (FXR) agonists would be considered as an important therapeutic strategy for several chronic liver and metabolic diseases. Here we have employed an integrated virtual screening by combining ligand-based pharmacophore mapping and molecular docking to identify novel nonsteroidal FXR agonists. Eighteen compounds were selected for in vitro FXR agonistic activity assay, and results showed five compounds exhibiting promising FXR agonistic activity. Among these compounds, compounds F4 and F17 were the most remarkable in vitro activity by using homogeneous time resolved fluorescence (HTRF) assay and the full-length FXR reporter gene assay in HepG2 cells. Real-time PCR assay was performed to measure the expression of FXR target genes. Compounds F4 and F17 increased small heterodimer partner (SHP), in turn, suppress mRNA levels of cholesterol 7-alpha-hydroxylase (CYP7A1). The obtained compounds F4 and F17 from this study may be potential leads for developing novel FXR agonists in the treatment of metabolic diseases.

UDP-glucuronosyltransferase (UGT) 1A1 is the only transferase capable of conjugating serum bilirubin. However, temporal delay in the development of the UGT1A1 gene leads to an accumulation of serum bilirubin in newborn children. Neonatal humanized UGT1 (hUGT1) mice, which accumulate severe levels of total serum bilirubin (TSB), were treated by oral gavage with obeticholic acid (OCA), a potent FXR agonist. OCA treatment led to dramatic reduction in TSB levels. Analysis of UGT1A1 expression confirmed that OCA induced intestinal and not hepatic UGT1A1. Interestingly, Cyp2b10, a target gene of the nuclear receptor CAR, was also induced by OCA in intestinal tissue. In neonatal hUGT1/Car -/- mice, OCA was unable to induce CYP2B10 and UGT1A1, confirming that CAR and not FXR is involved in the induction of intestinal UGT1A1. However, OCA did induce FXR target genes, such as Shp, in both intestines and liver with induction of Fgf15 in intestinal tissue. Circulating FGF15 activates hepatic FXR and, together with hepatic Shp, blocks Cyp7a1 and Cyp7b1 gene expression, key enzymes in bile acid metabolism. Importantly, the administration of OCA in neonatal hUGT1 mice accelerates intestinal epithelial cell maturation, which directly impacts on induction of the UGT1A1 gene and the reduction in TSB levels. Accelerated intestinal maturation is directly controlled by CAR, since induction of enterocyte marker genes sucrase-isomaltase, alkaline phosphatase 3, and keratin 20 by OCA does not occur in hUGT1/Car -/- mice. Thus, new findings link an important role for CAR in intestinal UGT1A1 induction and its role in the intestinal maturation pathway. SIGNIFICANCE STATEMENT: Obeticholic acid (OCA) activates FXR target genes in both liver and intestinal tissues while inducing intestinal UGT1A1, which leads to the elimination of serum bilirubin in humanized UGT1 mice. However, the induction of intestinal UGT1A1 and the elimination of bilirubin by OCA is driven entirely by activation of intestinal CAR and not FXR. The elimination of serum bilirubin is based on a CAR-dependent mechanism that facilitates the acceleration of intestinal epithelium cell differentiation, an event that underlies the induction of intestinal UGT1A1.

Epigallocatechin-3-gallate (EGCG) and caffeine constitute the most effective ingredients of weight loss in tea. However, whether combination of EGCG and caffeine exhibits anti-obesity synergy remains unclear. Here, we showed low-doses of EGCG and caffeine used in combination led to synergistic anti-obesity effects equivalent to those of high-dose EGCG. Furthermore, combination treatment exhibited a synergistic effect on altering gut microbiota, including decreased Firmicutes level and increased Bifidobacterium level. Other notable effects of combination treatment included synergistic effects on: increasing fecal acetic acid, propionic acid, and total SCFAs; decreasing expression of GPR43; and increasing microbial bile salt hydrolase gene copies in the gut, facilitating generation of unconjugated BAs and enhancing fecal BA loss. Additionally, combination treatment demonstrated synergistic effects toward increasing the expression of hepatic TGR5 and decreasing the expression of intestinal FXR-FGF15, resulting in increased expression of hepatic CYP7A1. Thus, the synergistic effect may be attributed to regulation of gut microbiota and BA metabolism.

Mung bean coat (MBC) is a good source of dietary fibre and phenolic compounds with medical properties, and can alleviate metabolic diseases. In the present study, the effects of MBC on high fat diet (HFD)-induced hyperlipidemia mice were evaluated, and the underlying mechanisms of MBC against hyperlipidemia from hepatic transcriptional analysis were explored. Four groups of mice were fed a normal control diet or a HFD with or without MBC supplementation (6%, w/w) for 12 weeks. The results demonstrated that MBC supplementation could effectively alleviate HFD-induced obese symptoms, such as body weight gain and white adipose tissue accumulation. Notably, the serum lipid profiles, including total triglyceride, total cholesterol, and low-density lipoprotein cholesterol, were significantly lowered, accompanied by a significant improvement in hepatic steatosis. RNA-sequencing analysis indicated 1126 differential expression genes responding to MBC supplementation, and the PPAR signaling pathway was significantly enriched. Furthermore, MBC supplementation could significantly upregulate the transcriptional expression of lipid transformation (lipidolysis)-related genes (Cpt1b, Cyp7a1, and PPAR-α) and downregulate the transcriptional expression of lipid synthesis-related genes (Scd1, Cd36, and PPAR-γ) to protect against the HFD-induced hyperlipidemia, and they were confirmed by qRCR and western blotting validation. Taken together, the present study provides valuable information for understanding the curative effects and action mechanism of MBC in alleviating hyperlipidemia, and thus may contribute to the development and application of MBC as functional foods or dietary supplement to protect against hyperlipidemia.

This study explored the effects of polyphenol extract (TKP) and essential oil (TKO) from Amomum tsao-ko Crevost et Lemaire (tsao-ko) on plasma total cholesterol and gut microbiota. Four groups of hamsters (n = 8 each) were fed one of four diets, respectively, namely a high-cholesterol diet (HCD) containing 0.1% cholesterol, a HCD containing 0.5% cholestyramine (PCD), a HCD with daily oral administration of 1000 mg per kg body weight TKP, and a HCD with daily oral administration of 200 mg per kg body weight TKO for 6 weeks. TKP and TKO equally lowered plasma total cholesterol (TC) by 13-18% via increasing the fecal elimination of total acidic sterols by 50-191%. This might be due to up-regulation of liver cholesterol 7α-hydroxylase (CYP7A1) at both transcriptional and translational levels. At a family level, TKP and TKO diets favorably modified the relative abundance of Ruminococcaceae, Erysipelotrichaceae, and Desulfovibrionaceae associated with acidic sterols and CYP7A1. It was therefore concluded that TKP and TKO were equally effective in alleviating hypercholesterolemia in hamsters via the interaction between gut microbiota and bile acid metabolism.

Stress can affect our body and is known to lead to some diseases. However, the influence on the development of nonalcohol fatty liver disease (NAFLD) remains unknown. This study demonstrated that chronic restraint stress attenuated hepatic lipid accumulation via elevation of hepatic β-muricholic acid (βMCA) levels in the development of nonalcoholic steatohepatitis (NASH) in mice. Serum cortisol and corticosterone levels, i.e., human and rodent stress markers, were correlated with serum bile acid levels in patients with NAFLD and methionine- and choline-deficient (MCD) diet-induced mice, respectively, suggesting that stress is related to bile acid (BA) homeostasis in NASH. In the mouse model, hepatic βMCA and cholic acid (CA) levels were increased after the stress challenge. Considering that a short stress enhanced hepatic CYP7A1 protein levels in normal mice and corticosterone increased CYP7A1 protein levels in primary mouse hepatocytes, the enhanced Cyp7a1 expression was postulated to be involved in the chronic stress-increased hepatic βMCA level. Interestingly, chronic stress decreased hepatic lipid levels in MCD-induced NASH mice. Furthermore, βMCA suppressed lipid accumulation in mouse primary hepatocytes exposed to palmitic acid/oleic acid, but CA did not. In addition, Cyp7a1 expression seemed to be related to lipid accumulation in hepatocytes. In conclusion, chronic stress can change hepatic lipid accumulation in NASH mice, disrupting BA homeostasis via induction of hepatic Cyp7a1 expression. This study discovered a new βMCA action in the liver, indicating the possibility that βMCA is available for NAFLD therapy.

We report a case of a novel phenotypic variant of cerebrotendinous xanthomatosis (CTX) with an adult onset, caused by 2 coexisting mutations involving the CYP7A1 and SLC10A1 genes. A 49-year-old male patient presented with eyelid xanthomatosis associated with dermatochalasis, nystagmus, right-sided paresis with hyperreflexia and atypical parkinsonism. Bilateral xanthomatous plaques involving both Achilles tendons were subsequently detected. Histopathology of the eyelids demonstrated marked diffuse stromal infiltrates of prominent foamy histiocytes. His lipid profile showed only a slightly elevated non-high density lipoprotein cholesterol level but with normal cholesterol and cholestanol levels. By contrast, classic CTX characteristically demonstrates a markedly elevated cholestanol and a mutation involving the CYP27A1 gene for enzyme cholesterol 27-hydroxylase. Unexpectedly, molecular studies on this patient revealed a heterozygous mutation involving 2 different genes, namely, CYP7A1 and SLC10A1 genes. The CYP7A1 gene encodes for the enzyme cholesterol 7α-hydroxylase, which is a rate-limiting enzyme in the cholesterol degradation. The SLC10A1 Na+/taurocholate cotransporter gene is involved in the enterohepatic circulation of bile acids and for the hepatocyte uptake of cholesterol. We are the first to report an unusual case of an adult-onset CTX manifesting with eyelid xanthomas associated with an uncharacteristic lipid profile and a detection of novel heterozygous mutations of CYP7A1 and SLC10A1 genes in this neurocutaneous syndrome.

The purpose of this study was to investigate whether dietary nuciferine affects lipid metabolism in broiler chickens. Four treatment groups were made from 120 1-day-old broiler chickens including the base diet group (normal control [NC], supplemented with 0 mg/kg of nuciferine) and groups treated with 25 mg/kg, 100 mg/kg, and 400 mg/kg of dietary nuciferine, which was supplemented for 42 d. The results showed that body weight, average daily weight gain, and absolute and relative fat and liver weight were significantly decreased with nuciferine supplementation. The plasma concentration of triiodothyronine, free triiodothyronine, thyroxine, and free thyroxine was significantly decreased in the nuciferine-supplemented group, but the plasma glucagon concentration was significantly increased. The plasma and hepatic triglyceride (TG) and total cholesterol (TC) concentrations were significantly decreased in the nuciferine group, but plasma and hepatic nonesterified fatty acid concentration, hepatic lipase activity, and hepatic glycogen content were significantly increased. Hepatic histological examination showed that fat cell volume and size in the 100 and 400 mg/kg group were smaller than those in the NC group. The fatty degeneration in the liver was decreased with nuciferine supplementation. The fat cell volume and size were shrunk in the nuciferine group. Dietary nuciferine supplementation significantly decreased the gene expression level of HMGCR, SREBP2, ACC, and SPEBP-1C, but significantly increased the gene expression level of LXR-α, CYP7A1, and CPT-I. The results indicated that nuciferine exhibited strong reduced fat deposition activities and reflected not only by decrease of the concentration of TG and TC but also by reduction in the key gene expression level of HMGCR, SREBP2, ACC, and SPEBP-1c and elevation of the key gene expression level of LXR-α, CYP7A1, and CPT-I. Taken together, our results suggested that the ability of nuciferine on reducing fat deposition in broiler chickens by regulating lipid metabolism was associated with the balance of TG and TC concentration.

Background and aims Hepatitis B virus (HBV) infection is ranked among the top health priorities worldwide. Accumulating evidence suggests that HBV infection and replication are closely associated with liver metabolism. The liver X receptors (LXRs), which belong to the superfamily of nuclear hormone receptors, are important physiological regulators of lipid and cholesterol metabolism. However, the association between the LXR pathway and HBV infection remains largely unclear. Approach and results In this study, the antiviral activity of LXR agonists was investigated using multiple HBV cellular models. We observed that in HBV-infected primary human hepatocytes (PHHs), synthetic LXR agonists (T0901317, GW3965, and LXR-623), but not an LXR antagonist (SR9238), potently inhibited HBV replication and gene expression, as demonstrated by substantial reductions in viral RNA, DNA, and antigen production following agonist treatment. However, covalently closed circular DNA (cccDNA) levels were not significantly reduced by the agonists. In addition, no rebound in viral replication was observed after treatment withdrawal, indicating a long-lasting inhibitory effect. These results suggest that LXR agonists decrease the transcriptional activity of cccDNA. In contrast, no significant anti-HBV effect was observed in HepG2-derived cell lines. Interestingly, LXR agonist treatment strongly reduced cholesterol 7α-hydroxylase 1 (CYP7A1) mRNA levels. Knockdown of CYP7A1 gene expression with small interfering RNA inhibited HBV activity in PHHs, suggesting CYP7A1 as a potential factor contributing to the antiviral effects of LXR agonists. Conclusions We found that activation of the LXR pathway with synthetic LXR agonists could elicit potent anti-HBV activity in PHHs, possibly through sustained suppression of cccDNA transcription. Our work highlights the therapeutic potential of targeting the LXR pathway for the treatment of chronic HBV infection.

Background & Aims Donation after brain death (DBD) grafts are associated with reduced graft quality and function post liver transplantation (LT). We aimed to elucidate i) the impact of FGF15 levels on DBD grafts; ii) whether this impact resulted from altered intestinal FXR-FGF15; iii) whether administration of FGF15 to donors after brain death could confer a benefit on graft function post LT; and iv) whether FGF15 affects bile acid (BA) accumulation. Methods Steatotic and non-steatotic grafts from DBD donors and donors without brain death were transplanted in rats. FGF15 was administered alone or combined with either a BA (cholic acid) or a YAP inhibitor. Results Brain death induced intestinal damage and downregulation of FXR. The resulting reduced intestinal FGF15 was associated with low hepatic FGF15 levels, liver damage and regenerative failure. Hepatic FGFR4-Klb – the receptor for FGF15 – was downregulated whereas CYP7A1 was overexpressed, resulting in BA accumulation. FGF15 administration to DBD donors increased hepatic FGFR4-Klb, reduced CYP7A1 and normalized BA levels. The benefit of FGF15 on liver damage was reversed by cholic acid, whereas its positive effect on regeneration was maintained. YAP signaling in DBD donors was activated after FGF15 treatment. When a YAP inhibitor was administered, the benefits of FGF15 on regeneration were abolished, whereas its positive effect on hepatic damage remained. Neither the Hippo-YAP-BA nor the BA-IQGAP1-YAP axis was involved in the benefits of FGF15. Conclusion Alterations in the gut-liver axis contribute to the reduced quality of DBD grafts and the associated pathophysiology of LT. FGF15 pre-treatment in DBD donors protected against damage and promoted cell proliferation. Lay summary After brain death, potential liver donors have reduced intestinal FXR, which is associated with reduced intestinal, circulatory and hepatic levels of FGF15. A similar reduction in the cell-surface receptor complex Fgfr4/Klb is observed, whereas CYP7A1 is overexpressed; together, these molecular events result in the dangerous accumulation of bile acids, leading to damage and regenerative failure in brain dead donor grafts. Herein, we demonstrate that when such donors receive appropriate doses of FGF15, CYP7A1 levels and hepatic bile acid toxicity are reduced, and liver regeneration is promoted.

Naringin, a major flavonoid in citrus, has potential for preventing atherosclerosis. The presence in the colon of a large amount of naringin after oral intake might affect the gut microbiota. We investigated the role of gut microbiota remodeling in the alleviation of atherosclerosis by naringin. Naringin significantly alleviated atherosclerosis and lowered the serum and liver cholesterol levels by 24.04 and 28.37% in ApoE-/- mice fed with a high-fat diet. Nontarget metabolomics showed that naringin modulated the hepatic levels of cholesterol derivatives and bile acids. Naringin increased the excretion of bile acids and neutral sterols by 1.6- and 4.3-fold, respectively. The main potential pathway by which naringin alleviated atherosclerosis was the gut microbiota-liver-cholesterol axis. Naringin modulated the abundances of bile salt hydrolase- and 7α-dehydroxylase-producing bacteria, promoting bile acid synthesis from cholesterol by upregulating CYP7A1 via suppression of the FXR/FGF15 pathway. In addition, naringin facilitated reverse cholesterol transport by downregulating PCSK9/IDOL. The results provide insight into the atherosclerosis-alleviation mechanisms of citrus flavonoids and a scientific basis for the development of functional foods containing citrus flavonoids.

Previous study suggested that dietary intake of Lactobacillus plantarum 06CC2 (LP06CC2) isolated from Mongolian dairy products showed various health beneficial effects. Here, the effect of LP06CC2 on the cholesterol metabolism in mice fed a cholesterol‐loaded diet was evaluated. Cholesterol and LP06CC2 were incorporated into the AIN93G‐based diet to evaluate the effect on cholesterol metabolism in Balb/c mice. Serum and liver cholesterol levels were significantly increased in mice fed a cholesterol‐loaded diet whereas the LP06CC2 ingestion suppressed the increase of liver cholesterol. LP06CC2 suppressed the increase of the hepatic damage indices. The increase of the cecal content and fecal butyrate were observed in mice fed LP06CC2. The analysis of bile acids clearly showed that LP06CC2 increased their deconjugation indicating the decrease of bile acid absorption. The protein expression of hepatic Cyp7A1 was also suppressed by LP06CC2 in mice fed cholesterol. Finally, in vitro studies showed that LP06CC2 had the most potent ability to deconjugate bile acids using glycocholate among the tested probiotic lactic acid bacteria isolated from Mongolian dairy products. Taken together, LP06CC2 is a promising microorganism for the reduction of the cholesterol pool via modulation of bile acid deconjugation., Lactobacillus plantarum 06CC2 (LP06CC2) is a Mongolian dairy product derived lactic acid bacteria. Ingestion of LP06CC2 decreased the liver cholesterol, hepatic damage, and increased fecal butyrate. LP06CC2 increased the deconjugation of bile acids to promote the excretion of bile acids. Together, LP06CC2 is a promising microorganism for the reduction of the cholesterol pool via modulation of bile acid deconjugation.

SP600125 is a classic inhibitor of c‑Jun‑N‑terminal kinase (JNK) that is widely used in numerous medicinal studies, but its administration regimen has yet to be optimized. In the present study, intraperitoneal (i.p.) and intragastric (i.g.) injections of 15 mg/kg SP600125 was performed in mice to compare the inhibitory effect against JNK signalling in cholestasis induced by α‑naphthylisothiocyanate (ANIT). SP600125 at a dose of 15 mg/kg administered by i.p. substantially decreased ANIT‑induced liver injury as observed by biochemical and histopathological examinations. The adaptation of bile acid synthesis was inhibited in the A‑SP‑i.p. group compared with that in the A‑SP‑i.g. group, as indicated by the expression analysis of CYP7A1 and CYP8B1. The transcription of the pro‑inflammatory factors IL‑6, IL‑1β, ICAM‑1 and IL‑10 supported the differential toxic responses. Western blot analysis revealed that JNK signalling activated by ANIT was inhibited more markedly in the A‑SP‑i.p. group than in the A‑SP‑i.g. group. The peak concentration and the AUC0‑24 of SP600125 in the A‑SP‑i.p. group were 5‑fold and 1.56‑fold higher, respectively, compared with those in the A‑SP‑i.g. group. These data indicated that i.p. administration of SP600125 produced a high plasma exposure profile, which directly determined its efficacy of blocking the JNK signalling. This effect of SP600125 on the JNK pathway may provide an optimized design for future in vivo investigations.

The aim of this study was to determine the effect of natural and encapsulated sources of ursolic acid on liver regeneration. Four ursolate sources were tested. Two forms of ursolic acid encapsulates were combined with cyclodextrins, i.e., gamma-CD (gCD) and beta-CD, and two natural sources were adjusted by homogenization (HAP) and micronization of apple peel using Jonagold apples. All ursolate forms were applied intragastrically in daily doses of 20 mg for 7 days. Laboratory rats were fed with standard laboratory diet. Further, gCD and MAP were also tested with a high-fat diet (6 weeks). Partial hepatectomy (PH) was performed 24 hours before the end of the experiment. The concentration of plasma hepatocyte growth factor (HGF) was determined with an immunoassay; simultaneously, the expression of HGF and CYP7A1 in the liver was quantified through qPCR. HGF expression and plasma levels were significantly increased 24 hours after PH in both the HAP (p=0.038) and HFgCD groups (p=0.036), respectively. The correlation between HGF expression and plasma values was significant (p=0.04). The positive effects on liver regeneration were found in both the gCD and HAP forms of ursolic acid, whose effects were confirmed through the upregulation of HGF.

Reverse cholesterol transport (RCT) and transintestinal cholesterol efflux (TICE) are two important pathways for body cholesterol elimination. We studied these pathways in an animal model of diabetes and obesity (ob/ob) where HDL function is compromised as a result of hyperglycemia, low-grade inflammation and oxidative stress. Co-treatment of ob/ob mice with PPAR-α (fenofibrate) and LXR (T0901317) agonists increased fecal cholesterol by 12-fold; PPAR-α and LXR agonists individually showed 2.6- and 4.0-fold fecal cholesterol excretion, respectively. We investigated the mechanism of synergistic efficacy of PPAR-α and LXR agonists in fecal cholesterol excretion. LXR agonist and the combination of PPAR-α and LXR agonists had greater HDL-C elevation. Ex vivo cholesterol efflux showed correlation with the fecal cholesterol excretion but was not sufficient to explain 12-fold increases in the fecal cholesterol in the co-treated mice. Therefore, we examined TICE to explain the 12-fold increases in the fecal cholesterol. A strong positive correlation of fecal cholesterol with ATP binding cassette transporter G5 (ABCG5) and G8 and anegative correlation with NPC1L1 was observed. ABCG5, G8 and NPC1L1 are involved in intestinal cholesterol absorption. The extent of influence of PPAR-α and LXR agonists on RCT and TICE was distinctly different. PPAR-α agonist increased fecal cholesterol primarily by influencing TICE, while LXR agonist influenced fecal cholesterol excretion via both RCT and TICE mechanisms. Synergistic efficacy on fecal cholesterol excretion following co-treatment with PPAR-α and LXR agonists occurred through a combination of RCT, TICE, and the key enzyme in bile synthesis, cholesterol 7-α hydroxylase (cyp7a1). These results suggest that cholesterol efflux, biliary cholesterol excretion, and TICE collectively contributed to the 12-fold increases in the fecal cholesterol excretion in ob/ob mice co-treated with PPAR-α and LXR agonists.

Cholesterol 7 alpha-hydroxylase (CYP7A1, EC1.14) is the first and rate-limiting enzyme in the classic bile acid synthesis pathway. Much progress has been made in understanding the transcriptional regulation of CYP7A1 gene expression and the underlying molecular mechanisms of bile acid feedback regulation of CYP7A1 and bile acid synthesis in the last three decades. Discovery of bile acid-activated receptors and their roles in the regulation of lipid, glucose and energy metabolism have been translated to the development of bile acid-based drug therapies for the treatment of liver-related metabolic diseases such as alcoholic and non-alcoholic fatty liver diseases, liver cirrhosis, diabetes, obesity and hepatocellular carcinoma. This review will provide an update on the advances in our understanding of the molecular biology and mechanistic insights of the regulation of CYP7A1 in bile acid synthesis in the last 40 years.

The gut microbe-derived metabolite trimethylamine-N-oxide (TMAO) has recently been linked to cardiovascular disease (CVD) pathogenesis, prompting the development of therapeutic strategies to reduce TMAO. Previous work has shown that experimental alteration of circulating TMAO levels via dietary alterations or inhibition of the host TMAO producing enzyme flavin containing monooxygenase 3 (FMO3) is associated with reorganization of host cholesterol and bile acid metabolism in mice. In this work, we set out to understand whether recently developed nonlethal gut microbe-targeting small molecule choline trimethylamine (TMA) lyase inhibitors also alter host cholesterol and bile acid metabolism. Treatment of mice with the mechanism-based choline TMA lyase inhibitor, iodomethylcholine (IMC), increased fecal neutral sterol loss in the form of coprostanol, a bacteria metabolite of cholesterol. In parallel, IMC treatment resulted in marked reductions in the intestinal sterol transporter Niemann-pick C1-like 1 (NPC1L1) and reorganization of the gut microbial community, primarily reversing choline supplemented diet-induced changes. IMC also prevented diet-driven hepatic cholesterol accumulation, causing both upregulation of the host hepatic bile acid synthetic enzyme CYP7A1 and altering the expression of hepatic genes critical for bile acid feedback regulation. These studies suggest that the gut microbiota-driven TMAO pathway is closely linked to both microbe and host sterol and bile acid metabolism. Collectively, as gut microbe-targeting choline TMA lyase inhibitors move through the drug discovery pipeline from preclinical models to human studies, it will be important to understand how these drugs impact both microbe and host cholesterol and bile acid metabolism. NEW & NOTEWORTHY The gut microbe-dependent metabolite trimethylamine-N-oxide (TMAO) has been strongly associated with cardiovascular mortality, prompting drug discovery efforts to identify points of therapeutic intervention within the microbe host TMAO pathway. Recently, mechanism-based small molecule inhibitors of the major bacterial trimethylamine (TMA) lyase enzymes have been developed, and these drugs show efficacy as anti-atherothrombotic agents. The novel findings of this study are that small molecule TMA lyase inhibition results in beneficial reorganization of host cholesterol and bile acid metabolism. This study confirms previous observations that the gut microbial TMAO pathway is intimately linked to host cholesterol and bile acid metabolism and provides further rationale for the development of small molecule choline TMA lyase inhibitors for the treatment of cardiometabolic disorders.

Maternal betaine was reported to regulate offspring hepatic cholesterol metabolism in mammals. However, it is unclear whether and how feeding betaine to laying hens affects hepatic cholesterol metabolism in offspring chickens. Rugao yellow-feathered laying hens (n = 120) were fed basal or 0.5% betaine-supplemented diet for 28 D before the eggs were collected for incubation. Maternal betaine significantly decreased the hepatic cholesterol content (P

OBJECTIVES Bile acid (BA) homeostasis is regulated by intestinal cellular signaling involving the farnesoid X receptor (FXR) and fibroblast growth factor 19 (FGF19) secretion. Using preterm and term pigs as a model, we examined postnatal changes in expression of the FXR-FGF19 axis that is poorly characterized in human infants. METHODS Pigs delivered by caesarean section at 10-day preterm and near full term (115-day gestation) were fitted with orogastric and umbilical arterial catheters. Pigs were fed combined parenteral nutrition and minimal enteral nutrition for 5 days, followed by milk formula until 26 d days. Plasma and tissue samples were collected at days 0, 5, 11, and 26. Plasma FGF19 concentration and liver and distal intestinal gene expression of FGF19 and other FXR target genes were quantified. RESULTS Plasma FGF19 levels were lower in preterm versus term newborn pigs (P