CYP7A1 Gene Induction via SHP-Dependent or Independent Mechanisms can Increase the Risk of Drug-Induced Liver Injury Independently or in Synergy with BSEP Inhibition.

Drug-induced liver injury (DILI) is a frequent cause of clinical trial failures during drug development. While inhibiting bile salt export pump (BSEP) is a well-documented DILI mechanism, interference with genes related to bile acid (BA) metabolism and transport can further complicate DILI development. Here, the effects of twenty-eight compounds on genes associated with BA metabolism and transport were evaluated, including those with discontinued development or use, boxed warnings, and clean labels for DILI. The study also included rifampicin and omeprazole, pregnane X receptor and aryl hydrocarbon receptor ligands, and four mitogen-activated protein kinase kinase (MEK1/2) inhibitors. BSEP inhibitors with more severe DILI, notably pazopanib and CP-724714, significantly upregulated the expression of 7 alpha-hydroxylase (CYP7A1), independent of small heterodimer partner (SHP) expression. CYP7A1 expression was marginally induced by omeprazole. In contrast, its expression was suppressed by mometasone (10-fold), vinblastine (18-fold), hexachlorophene (2-fold), bosentan (2.1-fold), and rifampin (2-fold). All four MEK1/2 inhibitors that show clinical DILI were not potent BSEP inhibitors but significantly induced CYP7A1 expression, accompanied by a significant SHP gene suppression. Sulfotransferase 2A1 and BSEP were marginally upregulated, but no other genes were altered by the drugs tested. Protein levels of CYP7A1 were increased with the treatment of CYP7A1 inducers and decreased with obeticholic acid, an farnesoid X receptor ligand. CYP7A1 inducers significantly increased bile acid (BA) production in hepatocytes, indicating the overall regulatory effects of BA metabolism. This study demonstrates that CYP7A1 induction via various mechanisms can pose a risk for DILI, independently or in synergy with BSEP inhibition, and it should be evaluated early in drug discovery. SIGNIFICANCE STATEMENT: Kinase inhibitors, pazopanib and CP-724714, inhibit BSEP and induce CYP7A1 expression independent of small heterodimer partner (SHP) expression, leading to increased bile acid (BA) production and demonstrating clinically elevated drug-induced liver toxicity. MEK1/2 inhibitors that show BSEP-independent drug-induced liver injury (DILI) induced the CYP7A1 gene accompanied by SHP suppression. CYP7A1 induction via SHP-dependent or independent mechanisms can pose a risk for DILI, independently or in synergy with BSEP inhibition. Monitoring BA production in hepatocytes can reliably detect the total effects of BA-related gene regulation for de-risking.

Mechanism of Tianma-Gouteng granules lowering blood pressure based on the bile acid-regulated Farnesoid X Receptor-Fibroblast Growth Factor 15- Cholesterol 7α-hydroxylase pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Tianma-Gouteng granules (TGG) is a traditional Chinese medicine (TCM) compound that was first recorded by modern medical practitioner Hu Guangci in "New Meaning of the Treatment of Miscellaneous Diseases in Traditional Chinese Medicine". It is widely used to treat hypertensive vertigo, headache and insomnia. AIM OF STUDY: To investigate the antihypertensive effect of TGG and explore its mechanism. MATERIALS AND METHODS: Spontaneously hypertensive rats (SHR) were prepared a model of the ascendant hyperactivity of liver yang syndrome (AHLYS), blood pressure and general state of rats were recorded. A series of experiments were performed by enzyme-linked immunosorbent assay (ELISA), ultra high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS), 16S rRNA sequencing, real-time fluorescence quantitative PCR (RT-qPCR), and enzymatic colorimetry. RESULTS: TGG can effectively lower blood pressure and improve related symptoms. TGG significantly reduced the levels of IL-1ß, IL-6, TNF-α, Renin and AngII. A total of 17 differential metabolites were found in plasma, with the two most potent metabolic pathways being glycerophospholipid metabolism and primary bile acid biosynthesis. After TGG intervention, 7 metabolite levels decreased and 10 metabolite levels increased. TGG significantly increased the relative abundance of Desulfovibio, Lachnoclostridium, Turicibacter, and decreased the relative abundance of Alluobaculum and Monoglobu. TGG also downregulated Farnesoid X Receptor (FXR) and Fibroblast Growth Factor 15 (FGF15) levels in the liver and ileum, upregulated Cholesterol 7α-hydroxylase (CYP7A1) levels, and regulated total bile acid (TBA) levels. CONCLUSION: TGG can regulate bile acid metabolism through liver-gut axis, interfere with related intestinal flora and plasma metabolites, decrease blood pressure, and positively influence the pathologic process of SHR with AHLYS. When translating animal microbiota findings to humans, validation studies are essential to confirm reliability and applicability, particularly through empirical human research.

Ginsenosides retard atherogenesis via remodelling host-microbiome metabolic homeostasis.

BACKGROUND AND PURPOSE: Panax ginseng is widely applied in the adjuvant treatment of cardiometabolic diseases in clinical practice without clear mechanisms. This study aims to clearly define the efficacy and underlying mechanism of P. ginseng and its active components in protecting against atherosclerosis. EXPERIMENTAL APPROACH: The anti-atherogenic efficacy of total ginseng saponin extract (TGS) and its components was evaluated on Ldlr-/- mice. Gut microbial structure was analysed by 16S rRNA sequencing and PCR. Bile acid profiles were revealed using targeted metabolomics with LC-MS/MS analysis. The contribution of gut microbiota to atherosclerosis was assessed by co-housing experiments. KEY RESULTS: Ginsenoside Rb1, representing protopanaxadiol (PPD)-type saponins, increased intestinal Lactobacillus abundance, resulting in enhanced bile salt hydrolase (BSH) activity to promote intestinal conjugated bile acid hydrolysis and excretion, followed by suppression of enterohepatic farnesoid X receptor (FXR)-fibroblast growth factor 15 (FGF15) signal, and thereby increased cholesterol 7α-hydroxylase (CYP7A1) transcriptional expression and facilitated metabolic elimination of cholesterol. Synergistically, protopanaxatriol (PPT)-type saponins, represented by ginsenoside Rg1, protected against atherogenesis-triggered gut leak and metabolic endotoxaemia. Ginsenoside Rg1 directly induced mucin production to nutritionally maintain Akkermansia muciniphila, which reciprocally inhibited gut permeation. Rb1/Rg1 combination, rather than a single compound, can largely mimic the holistic efficacy of TGS in protecting Ldlr-/- mice from atherogenesis. CONCLUSION AND IMPLICATIONS: Our study provides strong evidence supporting TGS and ginsenoside Rb1/Rg1 combinations as effective therapies against atherogenesis, via targeting different signal nodes by different components and may provide some elucidation of the holistic mode of herbal medicines.

Polymethoxyflavones in citrus extract has a beneficial effect on hypercholesterolemia rats by promoting liver cholesterol metabolism.

ETHNOPHARMACOLOGICAL RELEVANCE: Hyperlipidemia is characterized by the disorder of lipid metabolism accompanied by oxidative stress damage, and low-grade inflammation, with the pathway of cholesterol and bile acid metabolic are an important triggering mechanism. Polymethoxyflavones (PMFs) are the active constituents of Aurantii Fructus Immaturus, which have many biological effects, including anti-inflammatory, antioxidant activities, anti-obesity, suppressing adipogenesis in adipocytes, and ameliorate type 2 diabetes, with potential roles for regulation of lipid metabolism. However, its associated mechanisms on hyperlipidemia remain unclear. AIM OF THE STUDY: This study aims to identify the anti-hypercholesterolemia effects and mechanisms of PMFs in a hypercholesterolemia model triggered by high-fat compounds in an excessive alcohol diet (HFD). MATERIALS AND METHODS: A hypercholesterolemia rat model was induced by HFD, and PMFs was intragastric administered at 125 and 250 mg/kg daily for 16 weeks. The effects of PMFs on hypercholesterolemia were assessed using serum lipids, inflammatory cytokines, and oxidative stress levels. Hematoxylin & eosin (H&E) and Oil Red O staining were performed to evaluate histopathological changes in the rat liver. The levels of total cholesterol (TC) and total bile acid (TBA) in the liver and feces were determined to evaluate lipid metabolism. RAW264.7 and BRL cells loaded with NBD-cholesterol were used to simulate the reverse cholesterol transport (RCT) process in vitro. The signaling pathway of cholesterol and bile acid metabolic was evaluated by Western Blotting (WB) and qRT-PCR. RESULTS: Lipid metabolism disorders, oxidative stress injury, and low-grade inflammation in model rats were ameliorated by PMFs administration. Numerous vacuoles and lipid droplets in hepatocytes were markedly reduced. In vitro experiments results revealed decreased NBD-cholesterol levels in RAW264.7 cells and increased NBD-cholesterol levels in BRL cells following PMFs intervention. PMFs upregulated the expression of proteins associated with the RCT pathway, such as LXRα, ABCA1, LDLR, and SR-BI, thereby promoting TC entry into the liver. Meanwhile, the expression of proteins associated with cholesterol metabolism and efflux pathways such as CYP7A1, CYP27A1, CYP7B1, ABCG5/8, ABCB1, and BSEP were regulated, thereby promoting cholesterol metabolism. Moreover, PMFs treatment regulated the expression of proteins related to the pathway of enterohepatic circulation of bile acids, such as ASBT, OSTα, NTCP, FXR, FGF15, and FGFR4, thereby maintaining lipid metabolism. CONCLUSIONS: PMFs might ameliorate hypercholesterolemia by promoting the entry of cholesterol into the liver through the RCT pathway, followed by excretion via metabolism pathways of cholesterol and bile acid. These findings provide a promising therapeutic potential for PMFs to treat hypercholesterolemia.

Pharmacological modulation of cholesterol 7α-hydroxylase (CYP7A1) as a therapeutic strategy for hypercholesterolemia.

Despite the availability of many therapeutic options, the prevalence of hypercholesterolemia remains high. There exists a significant unmet medical need for novel drugs and/or treatment combinations to effectively combat hypercholesterolemia while minimizing adverse reactions. The modulation of cholesterol 7α-hydroxylase (CYP7A1) expression via perturbation of the farnesoid X receptor (FXR) - dependent pathways, primarily FXR/small heterodimer partner (SHP) and FXR/ fibroblast growth factor (FGF)-19/ fibroblast growth factor receptor (FGFR)-4 pathways, presents as a potential option to lower cholesterol levels. This paper provides a comprehensive review of the important role that CYP7A1 plays in cholesterol homeostasis and how its expression can be exploited to assert differential control of bile acid synthesis and cholesterol metabolism. Additionally, the paper also summarizes the current therapeutic options for hypercholesterolemia, and positions modulators of CYP7A1 expression, namely FGFR4 inhibitors and FXR antagonists, as emerging and distinct pharmacological agents to complement and diversify the treatment regime. Their mechanistic and clinical considerations are also extensively described to interrogate the benefits and risks associated with using FXR-mediating agents, either singularly or in combination with recognised agents such as statins to target hypercholesterolemia.

[Yacon root extract improves lipid metabolism in hyperlipidemic rats by inhibiting HMGCR expression and activating the PPARα/CYP7A1/CPT-1 pathway].

OBJECTIVE: To investigate the effect of yacon root extract on lipid metabolism in rats with hyperlipidemia (HLP) and its underlying mechanisms. METHODS: SD rat models of HLP induced by high- fat diet feeding for 8 weeks were randomized into the model group, fenofibrate treatment group (27 mg/kg), and yacon extract treatment groups at doses of 5, 2.5 and 1.25 g/kg (n=10). The rats were given corresponding drug treatments via gavage for 8 weeks. After the treatments, the rats were observed for body weight changes, liver coefficient, liver pathology, and serum levels of triglycerides (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C). The mRNA and protein expressions of HMGCR, PPARα, CYP7A1, and CPT-1 in the liver were detected using RT-qPCR and Western blotting. RESULTS: Compared with those in the model group, the rats treated with fenofibrate and 5 g/kg yacon root extract showed significantly slower body weight gain and lower liver coefficient (P < 0.05) with lower serum levels of TG, TC, and LDL- C (P < 0.05) but higher HDL- C level (P < 0.05). The HLP rat models showed obvious fatty degeneration and vacuolar changes in the liver, which were significantly alleviated by fenofibrate treatment and by treatment with yacon root extract in a dose-dependent manner. Both fenofibrate and 5 g/kg yacon root extract significantly lowered the mRNA and protein expression levels of HMGCR (P < 0.001) and increased the expressions of PPARα, CYP7A1, and CPT-1 in the liver of HLP rats (P < 0.001). CONCLUSION: Yacon root extract can reduce serum TG and TC levels in HLP rats possibly by inhibiting HMGCR expression and activating the PPARα/CYP7A1/CPT-1 signaling pathway, thereby promoting fatty acid ß oxidation and bile acid metabolism.

Cloning and Characterization of Cyp7a1 and Cyp27a1 Genes from the Non-Parasitic Japanese Lamprey Lethenteron reissneri.

Two cytochrome P450 genes homologous to human CYP7A1 and CYP27A1 were cloned from the non-parasitic Japanese lamprey Lethenteron reissneri. Lamprey cyp7a1 mRNA had varied expression levels among individuals: about four orders of magnitude differences in larval liver and nearly three orders of magnitude differences in male adult liver. Overexpressed Cyp7a1 protein tagged with green fluorescent protein (GFP) was localized to the endoplasmic reticulum. Lamprey cyp27a1 mRNA had relatively constant expression levels: within two orders of magnitude differences in larvae and adult liver and intestine. GFP-tagged Cyp27a1 protein was localized to mitochondria. The expression profiles of lamprey cyp7a1 and cyp27a1 genes and the cellular localizations of their products were in good agreement with their counterparts in mammals, where these two P450s catalyze initial hydroxylation reactions of cholesterol in classical and alternative pathways of bile acid synthesis, respectively. The cyp7a1 mRNA levels in adult male liver showed significant negative correlations to both body weight and total length of the animal, implying the involvement of the gene in the production of female-attractive pheromones in sexually matured male livers. The lamprey Cyp7a1 contains a long extension of 116 amino acids between helices D and E of the protein. Possible roles of this extension in regulating the enzymatic activity of lamprey Cyp7a1 are discussed.

Circadian PER1 controls daily fat absorption with the regulation of PER1-PKA on phosphorylation of bile acid synthetase.

Several epidemiological studies suggest a correlation between eating time and obesity. Night eating syndrome characterized by a time-delayed eating pattern is positively associated with obesity in humans as well as in experimental animals. Here, we show that oil intake at night significantly makes more fat than that at day in wild-type mice, and circadian Period 1 (Per1) contributes to this day-night difference. Per1-knockout mice are protected from high-fat diet-induced obesity, which is accompanied by a reduction in the size of the bile acid pool, and the oral administration of bile acids restores fat absorption and accumulation. We identify that PER1 directly binds to the major hepatic enzymes involved in bile acid synthesis such as cholesterol 7alpha-hydroxylase and sterol 12alpha-hydroxylase. A biosynthesis rhythm of bile acids is accompanied by the activity and instability of bile acid synthases with PER1/PKA-mediated phosphorylation pathways. Both fasting and high fat stress enhance Per1 expression, increasing the fat absorption and accumulation. Our findings reveal that Per1 is an energy regulator and controls daily fat absorption and accumulation. Circadian Per1 controls daily fat absorption and accumulation, suggesting Per1 is a potential candidate of a key regulator in stress response and the relevant obesity risk.

Targeting mTOR/YY1 signaling pathway by quercetin through CYP7A1-mediated cholesterol-to-bile acids conversion alleviated type 2 diabetes mellitus induced hepatic lipid accumulation.

BACKGROUND: Hepatic lipid accumulation was a major promoter for the further development of non-alcoholic fatty liver disease (NAFLD) in type 2 diabetes (T2DM). mTOR/YY1 signaling pathway regulated many metabolic processes in different organs, and played an important role in hepatic lipid metabolism. Thus, targeting mTOR/YY1 signaling pathway might be a novel therapeutic strategy of T2DM-associated NALFD. PURPOSE: To investigate the effects and the mechanism of quercetin against T2DM-associated NAFLD. STUDY DESIGN AND METHODS: The combine abilities of 24 flavonoid compounds with mTOR were detected by computer virtual screening (VS) and molecular modeling. mTOR/YY1 signaling pathway was examined in the liver of db/db mice, and high glucose (HG) and free fatty acid (FFA) co-cultured HepG2 cells. YY1 overexpression lentivirus vector and mTOR specific inhibitor rapamycin were used to further identify the indispensable role of mTOR/YY1 signaling pathway in quercetin's amelioration effect of hepatic lipid accumulation in vitro. Clinical studies, luciferase assay and chromatin immunoprecipitation (ChIP) assay were all carried out to investigate the potential mechanisms by which quercetin exerted its amelioration effect of hepatic lipid accumulation. RESULTS: Quercetin had the strongest ability to combine with mTOR and could competitively occupy its binding pocked. Along with the alleviated hepatic injury by quercetin, mTOR/YY1 signaling pathway was down-regulated in vivo and in vitro. However, the alleviation effect of quercetin against hepatic lipid accumulation was inhibited by YY1 overexpression in vitro. Mechanistically, the down-regulated nuclear YY1 induced by quercetin directly bound to CYP7A1 promoter and activated its transcription, resulting in the restoration of cholesterol homeostasis via the conversion of cholesterol-to-bile acids (BAs). CONCLUSION: The hepatoprotective effect of quercetin on T2DM-associated NAFLD was linked to the restoration of cholesterol homeostasis by the conversion of cholesterol-to-BAs via down-regulating mTOR/YY1 signaling pathway, leading to the increased CYP7A1 activity.

Pharmacological inhibition of MEK1/2 signaling disrupts bile acid metabolism through loss of Shp and enhanced Cyp7a1 expression.

The RAS-MAPK signaling pathway is one of the most frequently dysregulated pathways in human cancer. Small molecule inhibitors directed against this pathway have clinical activity in patients with various cancer types and can improve patient outcomes. However, the use of these drugs is associated with adverse effects, which can result in dose reduction or treatment interruption. A better molecular understanding of on-target, off-tumor effects may improve toxicity management. In the present study, we aimed to identify early initiating biological changes in the liver upon pharmacological inhibition of the RAS-MAPK signaling pathway. To this end, we tested the effect of MEK inhibitor PD0325901 using mice and human hepatocyte cell lines. Male C57BL/6 mice were treated with either vehicle or PD0325901 for six days, followed by transcriptome analysis of the liver and phenotypic characterization. Pharmacological MEK inhibition altered the expression of 423 genes, of which 78 were upregulated and 345 were downregulated. We identified Shp, a transcriptional repressor, and Cyp7a1, the rate-limiting enzyme in converting cholesterol to bile acids, as the top differentially expressed genes. PD0325901 treatment also affected other genes involved in bile acid regulation, which was associated with changes in the composition of plasma bile acids and composition and total levels of fecal bile acids and elevated predictive biomarkers of early liver toxicity. In conclusion, short-term pharmacological MEK inhibition results in profound changes in bile acid metabolism, which may explain some of the clinical adverse effects of pharmacological inhibition of the RAS-MAPK pathway, including gastrointestinal complications and hepatotoxicity.

L-Theanine regulates lipid metabolism by modulating gut microbiota and bile acid metabolism.

BACKGROUND: l-Theanine (LTA) is a biologically active ingredient in tea that shows great potential for regulating lipid metabolism. Bile acids (BA), an important end-product of cholesterol catabolism, participate in the regulation of lipid metabolism and gut microbiota. Here, we investigated the effect of LTA on lipid metabolism and the mechanism by which it regulates BA metabolism and gut microbiota. Male BALB/c mice were treated with LTA for 28 days. RESULTS: Daily LTA doses of 100 and 300 mg kg-1  d-1 altered the gut microbiota in mice, predominantly by decreasing Lactobacillus, Streptococcus, Bacteroides, Clostridium and Enterorhabdus microbes associated with bile-salt hydrolase (BSH) activity, thereby decreasing the activity of BSH and increasing the levels of ileum conjugated BA (such as glycocholic acid (GCA) and lithocholic acid), thereby inhibiting the intestinal farnesoid X receptor (FXR)-fibroblast growth factor 15 (FGF15) signaling pathway. Inhibition of FXR-FGF15 signaling was accompanied by upregulation of cholesterol 7α-hydroxylase (CYP7A1) mRNA and protein expression and increased hepatic production of cholic acid, deoxycholic acid, GCA, glycine cholic acid and glycine ursodeoxycholic acid. Meanwhile, increasing hepatic unconjugated BA upregulated the mRNA and protein expression of liver 3-hydroxy-3-methylglutaryl-CoA reductase and downregulated the mRNA and protein expression of stearoyl-CoA desaturase-1, liver low-density lipoprotein receptor and type B scavenger receptor. Therefore, the serum levels of cholesterol and triglycerides decreased. CONCLUSION: Our findings indicate that LTA regulates lipid metabolism by modulating the gut microbiota and BA metabolism via the FXR-FGF15-CYP7A1 pathway. © 2022 Society of Chemical Industry.

Maternal Low-Protein Diet during Puberty and Adulthood Aggravates Lipid Metabolism of Their Offspring Fed a High-Fat Diet in Mice.

A maternal low-protein (LP) diet during gestation and/or lactation results in metabolic syndrome in their offspring. Here, we investigated the effect of maternal LP diet during puberty and adulthood on the metabolic homeostasis of glucose and lipids in offspring. Female mice were fed with normal-protein (NP) diet or a LP diet for 11 weeks. Male offspring were then fed with a high-fat diet (NP-HFD and LP-HFD groups) or standard chow diet (NP-Chow and LP-Chow groups) for 4 months. Results showed that maternal LP diet during puberty and adulthood did not alter the insulin sensitivity and hepatic lipid homeostasis of their offspring under chow diet, but aggravated insulin resistance, hepatic steatosis, and hypercholesterolemia of offspring in response to a post-weaning HFD. Accordingly, transcriptomics study with offspring's liver indicated that several genes related to glucose and lipid metabolism, including lipoprotein lipase (Lpl), long-chain acyl-CoA synthetase 1 (Acsl1), Apoprotein A1 (Apoa1), major urinary protein 19 (Mup19), cholesterol 7α hydroxylase (Cyp7a1) and fibroblast growth factor 1 (Fgf1), were changed by maternal LP diet. Taken together, maternal LP diet during puberty and adulthood could disarrange the expression of metabolic genes in the liver of offspring and aggravate insulin resistance and hepatic steatosis in offspring fed a HFD.

Histology and metabonomics reveal the toxic effects of kresoxim-methyl on adult zebrafish.

Studies have shown that kresoxim-methyl (KM) and other strobilurin fungicides have toxic effects on aquatic organisms. However, the potential deleterious effects of kresoxim-methyl (KM) on adult zebrafish regarding the ecological risk of environmental concentration remain unclear. Here, the histology and untargeted metabonomics was used to investigate the adverse effect on female zebrafish after exposure to KM at environmental concentration, aquatic life benchmark and one-half LC50 of adult zebrafish. Results demonstrated KM affected zebrafish liver, ovary and intestine development, blurred the boundary between hepatocytes or caused hepatic vacuoles, increased the percentage of perinucleolar oocyte and cortical alveolus oocyte, decreased intestinal goblet cells and disturbed villus and wall integrity after 21 d exposure. Metabonomics showed different concentrations of KM simultaneously influenced the metabolites annotated to vitamin digestion and absorption, serotonergic synapse, retinol metabolism, ovarian steroidogenesis and arachidonic acid (AA) metabolism in zebrafish liver. Results showed the decreased triglyceride and cholesterol levels, as well as the metabolic alterations in amino acid, lipid, vitamin and retinol metabolism caused by KM, might disturb the energy supply for normal liver development and oocyte maturation. In addition, KM altered the transcription of Tdo2a, Tdo2b, Ido1, Cxcl8b, Cyp7a, Cyp11a, Cyp11b, Cyp17a, Cyp19a, Hsd3ß, Hsd17ß, Pla2, Ptgs2a and Ptgs2b, the level of TG, TC, MDA, IFN, IL6 and Ca2+, and the activity of CAT, SOD Ca2+-ATPase in zebrafish liver. Moreover, cytoscape analysis suggested the disturbed AA metabolism caused by KM, might interconnect multiple metabolic pathways to share implicated function in the regulation of oocyte maturation and immune response. Current study brought us closer to an incremental understanding of the toxic mechanism of KM on adult zebrafish, indicated there was crosstalk among different regulatory pathways to regulate the metabolic disorders and biologically hazardous effects induced by KM.

Pineapple fruit improves vascular endothelial dysfunction, hepatic steatosis, and cholesterol metabolism in rats fed a high-cholesterol diet.

Hypercholesterolaemia is a significant risk factor for developing vascular disease and fatty liver. Pineapple (Ananas comosus), a tropical fruit widely cultivated in Asia, is reported to exhibit antioxidant and cholesterol-lowering activity; however, the potential hypolipidaemic mechanisms of pineapple fruit remain unknown. Therefore, we aimed to identify the anti-hypercholesterolaemic mechanism of pineapple fruit and to study the effect of pineapple fruit intake on hypercholesterolaemia-induced vascular dysfunction and liver steatosis in a high-cholesterol diet (HCD)-fed rats. Male Sprague Dawley rats were fed with standard diet or HCD, and the pineapple fruit was orally administered to HCD-fed rats for 8 weeks. At the end of treatment, vascular reactivity and morphology of aortas, as well as serum nitrate/nitrite (NOx), were determined. Liver tissues were also examined for histology, lipid content, 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) activity, and protein expression of cholesterol metabolism-related enzymes. Results showed that pineapple fruit reduced the levels of hepatic cholesterol and triglycerides, and improved histological characteristics of a fatty liver in HCD-fed rats. Pineapple fruit also increased serum NOx, restored endothelium-dependent vasorelaxation, and reduced structural alterations in aortas of rats fed the HCD. In addition, a reduction of HMGCR activity and the downregulation of hepatic expression of HMGCR and sterol-regulatory element-binding protein 2 (SREBP2), as well as the upregulation of hepatic expression of cholesterol 7α-hydroxylase (CYP7A1) and LDL receptor (LDLR) were found in pineapple fruit-treated hypercholesterolaemic rats. These results indicate that pineapple fruit consumption can restore fatty liver and protect vascular endothelium in diet-induced hypercholesterolaemia through an improvement of hepatic cholesterol metabolism.

Capsaicin regulates dyslipidemia by altering the composition of bile acids in germ-free mice.

The improvement of lipid metabolism by capsaicin (CAP) has been extensively studied, mostly with respect to the vanilloid type 1 (TRPV1) ion channel and intestinal flora. In this study, a model was established in germ-free mice by using resiniferatoxin (RTX) to ablate TRPV1 ion channels. Bile acid composition, blood parameters, and colonic transcriptome analyses revealed that CAP could improve dyslipidemia caused by high-fat diet even in the absence of TRPV1 ion channels and intestinal flora. CAP fed to germ mice decreased the concentrations of low-density lipoprotein cholesterol (LDL-C), triglycerides (TG), fasting blood glucose and fasting insulin, increased the concentration of high-density lipoprotein (HDL-C), and decreased the levels of plasma endotoxin and pro-inflammatory factor interleukin 6 (IL-6). Furthermore, CAP could affect both classical and alternative pathways of cholesterol conversion by changing the composition of bile acids, reducing the concentrations of glycocholic acid (GCA), ursodeoxycholic acid (UDCA) and glycochenodeoxycholic acid (GCDCA). First, changing the composition of bile acids inhibited the expression of colon Fgf15. CAP promoted the expression of Cyp7a1 (Cytochrome p450, family 7, subfamily a, and polypeptide 1) in the liver, and thus reduced TC and TG levels. In addition, it could change the composition of bile acids and increase the expression of Cyp7b1 (Cytochrome p450, family 7, subfamily b, and polypeptide 1) in the colon, increase Cyp7b1 protein in the liver and thus inhibit fat accumulation. In conclusion, CAP could alter the composition of bile acids and promote the conversion of cholesterol to bile acids, thereby improving lipid metabolism abnormalities caused by a high-fat diet.

Portulaca oleracea L. Extract Regulates Hepatic Cholesterol Metabolism via the AMPK/MicroRNA-33/34a Pathway in Rats Fed a High-Cholesterol Diet.

This study examined the effect of extruded Portulaca oleracea L. extract (PE) in rats fed a high-cholesterol diet through the AMP-activated protein kinase (AMPK) and microRNA (miR)-33/34a pathway. Sprague-Dawley rats were randomized into three groups and fed either a standard diet (SD), a high-cholesterol diet containing 1% cholesterol and 0.5% cholic acid (HC), or an HC diet containing 0.8% PE for 4 weeks. PE supplementation improved serum, liver, and fecal lipid profiles. PE upregulated the expression of genes involved in cholesterol efflux and bile acids' synthesis such as liver X receptor alpha (LXRα), ATP-binding cassette subfamily G5/G8 (ABCG5/8), and cholesterol 7 alpha-hydroxylase (CYP7A1), and downregulated farnesoid X receptor (FXR) in the liver. In addition, hepatic gene expression levels of apolipoprotein A-l (apoA-1), paraoxonase 1 (PON1), ATP-binding cassette subfamily A1/G1 (ABCA1/G1), lecithin-cholesterol acyltransferase (LCAT), and scavenger receptor class B type 1 (SR-B1), which are related to serum high-density lipoprotein cholesterol metabolism, were upregulated by PE. Furthermore, hepatic AMPK activity in the PE group was higher than in the HC group, and miR-33/34a expression levels were suppressed. These results suggest that PE improves the cholesterol metabolism by modulating AMPK activation and miR-33/34a expression in the liver.

FXR Signaling-Mediated Bile Acid Metabolism Is Critical for Alleviation of Cholesterol Gallstones by Lactobacillus Strains.

Cholesterol gallstone (CGS) disease is characterized by an imbalance in bile acid (BA) metabolism and is closely associated with gut microbiota disorders. However, the role and mechanism by which probiotics targeting the gut microbiota attenuate cholesterol gallstones are still unknown. In this study, Limosilactobacillus reuteri strain CGMCC 17942 and Lactiplantibacillus plantarum strain CGMCC 14407 were individually administered to lithogenic-diet (LD)-fed mice for 8 weeks. Both Lactobacillus strains significantly reduced LD-induced gallstones, hepatic steatosis, and hyperlipidemia. These strains modulated BA profiles in the serum and liver, which may be responsible for the activation of farnesoid X receptor (FXR). At the molecular level, L. reuteri and L. plantarum increased ileal fibroblast growth factor 15 (FGF15) and hepatic fibroblast growth factor receptor 4 (FGFR4) and small heterodimer partner (SHP). Subsequently, hepatic cholesterol 7α-hydroxylase (CYP7A1) and oxysterol 7α-hydroxylase (CYP7B1) were inhibited. Moreover, the two strains enhanced BA transport by increasing the levels of hepatic multidrug resistance-associated protein homologs 3 and 4 (Mrp3/4), hepatic multidrug resistance protein 2 (Mdr2), and the bile salt export pump (BSEP). In addition, both L. reuteri and L. plantarum reduced LD-associated gut microbiota dysbiosis. L. reuteri increased the relative abundance of Muribaculaceae, while L. plantarum increased that of Akkermansia. The changed gut microbiota was significantly negatively correlated with the incidence of cholesterol gallstones and the FXR-antagonistic BAs in the liver and serum and with the FXR signaling pathways. Furthermore, the protective effects of the two strains were abolished by both global and intestine-specific FXR antagonists. These findings suggest that Lactobacillus might relieve CGS through the FXR signaling pathways. IMPORTANCE Cholesterol gallstone (CGS) disease is prevalent worldwide. None of the medical options for prevention and treatment of CGS disease are recommended, and surgical management has a high rate of recurrence. It has been reported that the factors involved in metabolic syndrome are highly connected with CGS formation. While remodeling of dysbiosis of the gut microbiome during improvement of metabolic syndrome has been well studied, less is known about prevention of CGS formation after regulating the gut microbiome. We used the lithogenic diet (LD) to induce an experimental CGS model in C57BL/6J mice to investigate protection against CGS formation by Limosilactobacillus reuteri strain CGMCC 17942 and Lactiplantibacillus plantarum strain CGMCC 14407. We found that these L. reuteri and L. plantarum strains altered the bile acid composition in mice and improved the dysbiosis of the gut microbiome. These two Lactobacillus strains prevented CGS formation by fully activating the hepatic and ileal FXR signaling pathways. They could be a promising therapeutic strategy for treating CGS or preventing its recurrence.

Mechanisms for Bile Acids CDCA- and DCA-Stimulated Hepatic Spexin Expression.

Spexin (SPX) is a novel peptide involved in glucose and lipid metabolism and suppresses hepatic total bile acid levels by inhibiting hepatic cholesterol 7α-hydroxylase 1 expression. As important mediators for glycolysis/gluconeogenesis and lipid metabolism, the effects of bile acids on SPX expression is yet to be understood. By using SMMC7721 and BEL-7402 cell lines, we screened the effects of bile acids and found that chenodeoxycholic acid (CDCA) and deoxycholic acid (DCA) can stimulate SPX gene transcription. Both CDCA and DCA were able to stimulate SPX mRNA expression in the liver but not colon and ileum in mice. In SMMC7721 and BEL-7402 cells, CDCA- and DCA-induced SPX promoter activity was mimicked by bile acid receptor FXR and TGR5 activation and suppressed by FXR and TGR5 silencing. Adenylate cyclase (AC)/cyclic adenosine monophosphate (cAMP) activators significantly increased SPX promoter activity whereas the inhibitors for AC/CAMP/protein kinase A (PKA) and mitogen-activated protein kinases (MAPK) pathway attenuated CDCA- and DCA-induced SPX transcription. Thus, CDCA and DCA stimulate SPX expression at the hepatic level through FXR and TGR5 mediated AC/cAMP/PKA and MAPK cascades.

Nifuroxazide modulates hepatic expression of LXRs/SR-BI/CES1/CYP7A1 and LDL-R and attenuates experimentally-induced hypercholesterolemia and the associated cardiovascular complications.

Hyperlipidemia is a serious disorders affecting the metabolism of fats in the human body, and it is usually associated with some serious cardiovascular complications increasing the risk for sudden death. Nifuroxazide (NFR) is an oral nitrofuran antibiotic that has long been used for management of diarrhea and recently various recent out merging valuable therapeutic impacts were reported. The current study sought the concept of repositioning nifuroxazide in management of hyperlipidemia. Hyperlipidemia was induced in male rabbits using cholesterol enriched diet for 9 weeks and starting from the beginning of 5th week; NFR (100 and 300 mg/kg) were administered once daily for the further 5 weeks; till the end of the 9th week of the experiment. NFR significantly recovered balanced lipid profile as serum cholesterol, total glycerides, LDL significantly declined with significant elevation in serum HDL. Meanwhile, serum LDH, CK, ALT and AST activities were significantly corrected. These biochemical changes were correlated with significant improvement in the histopathological examination of hepatic, cardiac and aortic specimen with decreased expression of CD68 and Ki67 in the myocardium and the aorta implying retraction in macrophages' infiltration and tissue regeneration. Myocardial specimen confirmed significant recovery with preservation of cardiac muscle fibers. Aortic specimen confirmed retraction in the aortic thickness and fewer deposition of fat globules. In conclusion, NFR attenuated experimentally-induced hyperlipidemia with significant recovery of serum profile and tissue necrotic changes. The histopathological examination of hepatic, myocardial and aortic specimen confirmed the onset of tissues' recovery alongside biochemical improvement.

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.