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.

Diosgenin as a substitute for cholesterol alleviates NAFLD by affecting CYP7A1 and NPC1L1-related pathway.

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) rapidly becomes the leading cause of end-stage liver disease or liver transplantation. Nowadays, there has no approved drug for NAFLD treatment. Diosgenin as the structural analogue of cholesterol attenuates hypercholesterolemia by inhibiting cholesterol metabolism, which is an important pathogenesis in NAFLD progression. However, there has been no few report concerning its effects on NAFLD so far. METHODS: Using a high-fat diet & 10% fructose-feeding mice, we evaluated the anti-NAFLD effects of diosgenin. Transcriptome sequencing, LC/MS analysis, molecular docking simulation, molecular dynamics simulations and Luci fluorescent reporter gene analysis were used to evaluate pathways related to cholesterol metabolism. RESULTS: Diosgenin treatment ameliorated hepatic dysfunction and inhibited NAFLD formation including lipid accumulation, inflammation aggregation and fibrosis formation through regulating cholesterol metabolism. For the first time, diosgenin was structurally similar to cholesterol, down-regulated expression of CYP7A1 and regulated cholesterol metabolism in the liver (p < 0.01) and further affecting bile acids like CDCA, CA and TCA in the liver and feces. Besides, diosgenin decreased expression of NPC1L1 and suppressed cholesterol transport (p < 0.05). Molecular docking and molecular dynamics further proved that diosgenin was more strongly bound to CYP7A1. Luci fluorescent reporter gene analysis revealed that diosgenin concentration-dependently inhibited the enzymes activity of CYP7A1. CONCLUSION: Our findings demonstrated that diosgenin was identified as a specific regulator of cholesterol metabolism, which pave way for the design of novel clinical therapeutic strategies.

Kaempferol ameliorated alcoholic liver disease through inhibiting hepatic bile acid synthesis by targeting intestinal FXR-FGF15 signaling.

BACKGROUND: Alcoholic liver disease (ALD) is characterized by the disturbance of bile acids homeostasis, which further deteriorates ALD. Bile acid metabolism and its related signal molecules have become new therapeutic targets for alcoholic liver disease. This study aimed to investigate the impact of kaempferol (KAE) on ALD and elucidate its underlying mechanisms. METHODS: C57BL/6 N mice were utilized to establish Binge-on-Chronic alcohol exposure mice model. KAE was administered as an interventional drug to chronic alcohol-fed mice for four weeks to assess its effects on liver damage and bile acid metabolism. And Z-Guggulsterone (Z-Gu), a global FXR inhibitor, was used to investigate the impact of intestinal FXR-FGF15 signal in ALD mice. Additionally, intestinal epithelial cells were exposed to alcohol or specific bile acid to induce the damage of FXR activity in vitro. The dual luciferase activity assay was employed to ascertain the interplay between KAE and FXR activity. RESULTS: The results indicated that KAE treatment exhibited a significant hepatoprotective effect against chronic alcohol-fed mice. Accompanied by the intestinal FXR activation, the administration of KAE suppressed hepatic bile acid synthesis and promoted intestinal bile acid excretion in chronic ALD mice. And the notable alterations in total bile acid levels and composition were observed in mice after chronic alcohol feeding, which were reversed by KAE supplementation. And more, the protective effects of KAE on ALD mice were deprived by the inhibition of intestinal FXR activation. In vitro experiments demonstrated that KAE effectively activated FXR-FGF15 signaling, mitigated the damage to FXR activity in intestinal epithelial cells caused by alcohol or specific bile acids. Additionally, luciferase activity assays revealed that KAE directly promoted FXR expression, thereby enhancing FXR activity. CONCLUSION: KAE treatment inhibited hepatic bile acids synthesis, maintained bile acids homeostasis in ALD mice by directly activating intestinal FXR-FGF15 signaling, which effectively alleviated liver injury induced by chronic alcohol consumption.

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.

Effects of black raspberry extract on gut microbiota, microbial metabolites, and expressions of the genes involved in cholesterol and bile acid metabolisms in rats fed excessive choline with a high-fat diet.

In our previous study, black raspberry (BR) reduced the serum levels of trimethylamine-N-oxide and cholesterol in rats fed excessive choline with a high-fat diet (HFC). We hypothesized that gut microbiota could play a crucial role in the production of trimethylamine and microbial metabolites, and BR could influence gut microbial composition. This study aimed to elucidate the role of BR on changes in gut microbiota and microbial metabolites in the rats. The phylogenetic diversity of gut microbiota was reduced in the rats fed HFC, while that in the BR-fed group was restored. The BR supplementation enriched Bifidobacterium and reduced Clostridium cluster XIVa. In the BR-fed group, most cecal bile acids and hippuric acid increased, while serum lithocholic acid was reduced. The BR supplementation upregulated Cyp7a1 and downregulated Srebf2. These results suggest that BR extract may change gut bacterial community, modulate bile acids, and regulate gene expression toward reducing cholesterol. Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-023-01267-4.

Metabolic profiling of emodin drug-induced liver injury and silybin treatment in rats using ultra-performance liquid chromatography-quadrupole-time-of-flight-mass spectrometry: A metabolomic and mechanistic approach.

Silybin, an active component in the plant Silybum marianum (L.) Gaertn., is commonly used to protect against liver disease. We investigated silybin's protective potential in rat liver against emodin-induced liver injury 4 weeks. It was found that aspartate aminotransferase and direct bilirubin serum biomarkers for liver toxicity significantly increased, and liver histopathology revealed cholestasis and necrosis in rats administered emodin alone, whereas aspartate aminotransferase and total bile acid levels in rats administered emodin and silybin simultaneously were changed compared to rats administered emodin alone. Liver mRNA and protein levels of Cyp7a1-which plays roles in cholesterol metabolism and bile acid synthesis-and Abcb11 (Bsep)-which facilitates bile salt secretion in hepatocyte canaliculi-were significantly altered with emodin, whereas cotreatment with silybin attenuated emodin's adverse effect. Metabolomic analysis using ultra-performance liquid chromatography-quadrupole-time-of-flight-mass spectrometry determined eight potential metabolite biomarkers in serum, urine, and liver tissue. Network analysis was conducted to conceptualize the interplay of genes, metabolites, and metabolic pathways for cholesterol metabolism and bile acid synthesis for liver injury. Overall, rats administered only emodin were shown to be a sound model to investigate fat-associated drug-induced hepatoxicity or liver injury and cotreatment of emodin with silybin prevents fatty liver injury. This metabolomic study revealed that emodin-induced fatty liver injury disrupted bile acid synthesis, vitamin B6 , and glycerophospholipid metabolism pathways and that silybin ameliorates liver injury on these compromised pathways.

Cholesterol-lowering effects of taurine through the reduction of ileal FXR signaling due to the alteration of ileal bile acid composition.

Studies using animal models of hypercholesterolemia have established that taurine reduces cholesterol levels; however, the precise mechanism underlying this cholesterol-lowering effect is unclear. This study addressed this issue by investigating whether bile acid/farnesoid X receptor (FXR) signaling is involved in taurine-mediated cholesterol-lowering effect. Fxr-null and wild-type mice were administered 2% (w/v) taurine in their drinking water and fed a control diet or control diet supplemented with 1% (w/w) cholesterol (cholesterol diet) for 10 days. Taurine intake did not significantly alter hepatic and serum total cholesterol (TC) levels and bile acid compositions of the liver and intestinal lumen in Fxr-null and wild-type mice fed the control diet. By changing to a cholesterol diet, taurine intake significantly decreased hepatic and serum cholesterol levels in wild-type mice. In contrast, it significantly decreased hepatic, not serum, cholesterol levels in Fxr-null mice. Taurine intake significantly altered the bile acid composition of the intestinal lumen in wild-type mice fed a cholesterol diet, but not in Fxr-null mice. An increase in FXR antagonistic bile acids was detected in the intestinal lumen of taurine-treated wild-type mice fed a cholesterol diet. Taurine intake reduced the ileal expression of FXR target genes fibroblast growth factor 15 (Fgf15) and small heterodimer partner (Shp). In contrast, it enhanced the hepatic expression of cholesterol 7α-hydroxylase (Cyp7a1) in wild-type mice fed a cholesterol diet, but not in Fxr-null mice. These results suggest that taurine is partially involved in cholesterol lowering by reducing the ileal FXR signaling due to the alteration of ileal bile acid composition.

Gut-restricted apical sodium-dependent bile acid transporter inhibitor attenuates alcohol-induced liver steatosis and injury in mice.

BACKGROUND: Recent studies have shown that human and experimental alcohol-related liver disease (ALD) is robustly associated with dysregulation of bile acid homeostasis, which may in turn modulate disease severity. Pharmacological agents targeting bile acid metabolism and signaling may be potential therapeutics for ALD. METHODS: The potential beneficial effects of a gut-restricted apical sodium-dependent bile acid transporter (ASBT) inhibitor were studied in a chronic-plus-binge ALD mouse model. RESULTS: Blocking intestinal bile acid reabsorption by the gut-restricted ASBT inhibitor GSK2330672 attenuated hepatic steatosis and liver injury in a chronic-plus-binge ALD mouse model. Alcohol feeding is associated with intestinal bile acid accumulation but paradoxically impaired ileal farnesoid × receptor (FXR) function, and repressed hepatic cholesterol 7α-hydrolase (CYP7A1) expression despite decreased hepatic small heterodimer partner (SHP) and ileal fibroblast growth factor 15 (FGF15) expression. ASBT inhibitor treatment decreased intestinal bile acid accumulation and increased hepatic CYP7A1 expression, but further decreased ileal FXR activity. Alcohol feeding induces serum bile acid concentration that strongly correlates with a liver injury marker. However, alcohol-induced serum bile acid elevation is not due to intrahepatic bile acid accumulation but is strongly and positively associated with hepatic multidrug resistance-associated protein 3 (MRP4) and MRP4 induction but poorly associated with sodium-taurocholate cotransporting peptide (NTCP) expression. ASBT inhibitor treatment decreases serum bile acid concentration without affecting hepatocyte basolateral bile acid uptake and efflux transporters. CONCLUSION: ASBT inhibitor treatment corrects alcohol-induced bile acid dysregulation and attenuates liver injury in experimental ALD.

Network pharmacology analysis and experimental validation to explore the mechanism of sea buckthorn flavonoids on hyperlipidemia.

ETHNOPHARMACOLOGICAL RELEVANCE: Sea buckthorn is popularly used as a herbal medicine and food additive in the world. Sea buckthorn flavonoids (SF) is reported to have an ameliorative effect on obesity and hyperlipidemia (HLP). AIM: To identify the major bioactive compounds and the lipid-lowering mechanism of SF. METHODS: We used network pharmacology analysis and in vitro experiments to identify the major bioactive compounds and the lipid-lowering mechanism of SF. RESULTS: A total of 12 bioactive compounds, 60 targets related to SF and HLP were identified, and a component-target-disease network was constructed. The KEGG analysis revealed that SF regulated cholesterol metabolism, fat digestion and absorption, and PPAR signaling pathways in HLP. The experimental validation indicated that sea buckthorn flavonoids extract (SFE) and 4 bioactive compounds reduced lipid droplet accumulation, up-regulated the mRNA expression of PPAR-γ, PPAR-α, ABCA1 and CPT1A, etc, down-regulated SREBP-2 and its target gene LDLR, which are closely related to cholesterol conversion into bile acids, de novo synthesis and fatty acids oxidation. The major bioactive flavonoid isorhamnetin (ISOR) also increased the protein expression of PPAR-γ, LXRα and CYP7A1. CONCLUSION: SF might promote cholesterol transformation into bile acids and cholesterol efflux, inhibit cholesterol de novo synthesis and accelerate fatty acids oxidation for ameliorating HLP.

Effects of Lactobacillus plantarum PMO 08 Alone and Combined with Chia Seeds on Metabolic Syndrome and Parameters Related to Gut Health in High-Fat Diet-Induced Obese Mice.

This study researched the effects of Lactobacillus plantarum PMO 08 alone and combined with chia seeds on metabolic syndrome and parameters related to microbiota modulation and intestinal barrier integrity in obese mice fed high-fat diets (HFDs; 45% kcal fat). Male C57BL/6J mice were acclimated for a period of 2 weeks and then randomly separated into five groups depending on whether they received a normal diet (ND group), an HFD (HFD group), an HFD with L. plantarum (PMO group), an HFD with L. plantarum combined with chia seeds (PMOChia group), or an HFD with chia seeds (Chia group). Serum lipid profiles and related markers (cholesterol metabolism-related gene expression) were measured. Intestinal barrier integrity was assessed by measuring occludin mRNA expression of tight junction proteins. Mucosal bacteria were checked with quantitative reverse transcript polymerase chain reaction (qRT-PCR). After 16 weeks of feeding, the PMO group showed significantly lower serum total cholesterol, low-density lipoprotein cholesterol levels, atherogenic index, and cardiac risk factors compared to the HFD group. Moreover, the hepatic mRNA expression of SREBP2 (sterol regulatory element binding protein 2), a protein related to cholesterol metabolism, was significantly downregulated in the PMO group. We also found a positive synergistic effect in the PMOChia group, as manifested by the hepatic mRNA expression of hepatic CYP7A1 (cholesterol 7α-hydroxylase), strengthening of the gut barrier function, and the promotion of more L. plantarum in the colonic mucosa than in either the HFD or PMO group. In conclusion, our results indicate that PMO 08 may protect against metabolic syndrome by exerting effects on the regulation of lipid metabolism. Although the effects of chia seeds alone remain uncertain based on this experiment, its combination with PMO 08 was demonstrated to improve multiple beneficial effects of PMO 08 in obese mice fed HFD, which is a promising possibility for future research.

[Effects of electroacupuncture on CYP7A1 expression in liver of rabbits with atherosclerosis].

OBJECTIVE: To observe the effects of electroacupuncture (EA) at "Neiguan" (PC 6), "Guanyuan" (CV 4) and "Zusanli" (ST 36) on CYP7A1 expression in liver of rabbits with atherosclerosis (AS), and to explore the mechanism of acupuncture for prevention and treatment of atherosclerosis. METHODS: A total of 26 male rabbits were adaptively fed for 1 week in different cages. Seven rabbits were randomly divided into a blank group, and the remaining 19 rabbits were divided into a model group. The blank group was fed with normal diet, while the model group was fed with high-fat diet. After high-fat diet for 4 weeks, the rabbits in the model group were treated with balloon injury surgery of the common carotid artery; after surgery, the rabbits were fed with high-fat diet for 4 weeks. One rabbit was randomly selected from the blank group and model group to obtain the pathological section of carotid artery; the HE staining was used to observe the pathomorphology of atheromatous plaque to determine the success of modeling or not. After successful establishment of modeling, 18 rabbits were randomly divided into a AS model group, an EA group and a medication group, 6 rabbits in each one. The rabbits in the AS model group received no treatment; the rabbits in the medication group were treated with intragastric administration of atorvastatin calcium tablets; the rabbits in the EA group were treated with EA at "Neiguan" (PC 6), "Guanyuan" (CV 4) and "Zusanli" (ST 36), once a day, 20 min per treatment; six-day EA treatment constituted one course, and totally 4 courses were given with an interval of 1 day between courses. After treatment, vein blood was collected from rabbit ear, and cholesterol (CHO), triglyceride (TG), low-density lipoprotein (LDL) and high-density lipoprotein (HDL) were measured in each group; the CYP7A1 protein expression in rabbit liver was measured by Western blot method, and CYP7A1 mRNA expression in rabbit liver was measured by RT-PCR. RESULTS: Compared with the blank group, the contents of CHO, TG and LDL in the AS model group were significantly increased, but HDL was significantly decreased, and the expression of CYP7A1 protein and CYP7A1 mRNA in the liver were significantly decreased (all P<0.01). After treatment, compared with the model group, the contents of CHO, TG and LDL in the EA group and medication group were significantly reduced, but HDL was significantly increased, and the expression of CYP7A1 protein and CYP7A1 mRNA in the liver were significantly increased (all P<0.01). The significant difference of each outcome between the EA group and medication group was not observed (all P>0.05). CONCLUSION: EA could significantly improve blood lipid and promote the expression of CYP7A1 mRNA in rabbits with atherosclerotic, which may be one of the mechanisms of EA for atherosclerosis.

Effects of electroacupuncture on CYP7A1 expression in liver of rabbits with atherosclerosis / 中国针灸

OBJECTIVE@#To observe the effects of electroacupuncture (EA) at "Neiguan" (PC 6), "Guanyuan" (CV 4) and "Zusanli" (ST 36) on CYP7A1 expression in liver of rabbits with atherosclerosis (AS), and to explore the mechanism of acupuncture for prevention and treatment of atherosclerosis.@*METHODS@#A total of 26 male rabbits were adaptively fed for 1 week in different cages. Seven rabbits were randomly divided into a blank group, and the remaining 19 rabbits were divided into a model group. The blank group was fed with normal diet, while the model group was fed with high-fat diet. After high-fat diet for 4 weeks, the rabbits in the model group were treated with balloon injury surgery of the common carotid artery; after surgery, the rabbits were fed with high-fat diet for 4 weeks. One rabbit was randomly selected from the blank group and model group to obtain the pathological section of carotid artery; the HE staining was used to observe the pathomorphology of atheromatous plaque to determine the success of modeling or not. After successful establishment of modeling, 18 rabbits were randomly divided into a AS model group, an EA group and a medication group, 6 rabbits in each one. The rabbits in the AS model group received no treatment; the rabbits in the medication group were treated with intragastric administration of atorvastatin calcium tablets; the rabbits in the EA group were treated with EA at "Neiguan" (PC 6), "Guanyuan" (CV 4) and "Zusanli" (ST 36), once a day, 20 min per treatment; six-day EA treatment constituted one course, and totally 4 courses were given with an interval of 1 day between courses. After treatment, vein blood was collected from rabbit ear, and cholesterol (CHO), triglyceride (TG), low-density lipoprotein (LDL) and high-density lipoprotein (HDL) were measured in each group; the CYP7A1 protein expression in rabbit liver was measured by Western blot method, and CYP7A1 mRNA expression in rabbit liver was measured by RT-PCR.@*RESULTS@#Compared with the blank group, the contents of CHO, TG and LDL in the AS model group were significantly increased, but HDL was significantly decreased, and the expression of CYP7A1 protein and CYP7A1 mRNA in the liver were significantly decreased (all 0.05).@*CONCLUSION@#EA could significantly improve blood lipid and promote the expression of CYP7A1 mRNA in rabbits with atherosclerotic, which may be one of the mechanisms of EA for atherosclerosis.

Taiwanese Green Propolis Ethanol Extract Delays the Progression of Type 2 Diabetes Mellitus in Rats Treated with Streptozotocin/High-Fat Diet.

Taiwanese green propolis ethanol extract (TGPE) is produced only in Taiwan and has a different composition from other types of propolis. TGPE is known for its anti-inflammation, anti-oxidation, and anti-microbial properties, but the effects and mechanisms of TGPE in the modulation of diabetes are unclear. In this study, we investigated the effects of TGPE on type 2 diabetes mellitus (T2DM) in a streptozotocin/high-fat-diet (STZ/HFD)-induced T2DM rat model. The results revealed that TGPE delayed the development and progression of T2DM and reduced the severity of β-cell failure. TGPE also attenuated inflammation and reactive oxygen species ROS in the rats. Moreover, there were higher levels of oxidant cytokines, leptin, and adiponectin in the serum of the TGPE-treated group. Unlike Brazilian propolis, TGPE promoted hepatic genes PPAR-α and CYP7A1, which were related to lipid catabolism and removal. TGPE may thus delay the progression of T2DM through anti-inflammation effects, anti-oxidation effects, and balancing lipid metabolism. It is suggested that TGPE can be a potential alternative medicine for T2DM.

Dietary Wheat Bran Oil Is Equally as Effective as Rice Bran Oil in Reducing Plasma Cholesterol.

Rice bran oil (RBO) possesses a plasma cholesterol-lowering activity, while effect of wheat bran oil (WBO) on plasma cholesterol remains unknown. The present study compared the cholesterol-lowering activity of WBO with that of RBO in hamsters. Fifty-four male hamsters were divided into seven groups fed either a noncholesterol diet (NCD) or one of six high-cholesterol diets, namely HCD diet (0.2% cholesterol +9.5% lard), HCD+C diet (0.2% cholesterol +9.5% lard +0.5% cholestyramine), WL diet (0.2% cholesterol +4.8% Lard +4.8% WBO), WH diet (0.2% cholesterol +9.5% WBO), RL diet (0.2% cholesterol +4.8% Lard +4.8% RBO), and RH diet (0.2% cholesterol +9.5% RBO). Plasma total cholesterol (TC) in HCD group was 327.4 ± 31.8 mg/dL, while plasma TC in two WBO and two RBO groups was 242.2 ± 20.8, 243.1 ± 31.7, 257.1 ± 16.3, and 243.4 ± 46.0 mg/dL, respectively, leading to a decrease in plasma TC by 22-26% ( P < 0.01). No significant difference in cholesterol-lowering potency was seen between WBO and RBO. Plasma cholesterol-lowering activity of WBO and RBO was accompanied by down-regulation of hepatic 3-hydroxy-3-methylglutaryl-CoA reductase and fatty acid synthase, while up-regulation of cholesterol-7α-hydroxylase. WL, WH, RL, and RH diets increased the fecal excretion of total neutral sterols by 72.8%, 106.9%, 5.4%, and 36.8% ( P < 0.01) respectively. Results indicated WBO and RBO could inhibit cholesterol absorption via down-regulation of intestinal Niemann-Pick C1 like 1 protein, acyl CoA:cholesterol acyltransferase 2, and ATP binding cassette transporter 5. In summary, WBO was equally effective as RBO in decreasing plasma cholesterol in hypercholesterolemia hamsters.

Soybean amplifies the hypohomocysteinemic effect of betaine and improves its hypercholesterolemic effect.

We examined whether soybean (SB) and soy protein isolate (SPI) can prevent the betaine-induced elevation of plasma cholesterol as well as maintain the betaine-induced reduction of plasma Hcy concentration. Rats were fed casein-, SB-, or SPI-based diet with or without betaine; SPI-based diet with betaine containing soybean fiber (SF) or soy lecithin (SL) or the combination of SF and SL. Plasma Hcy concentration was decreased by feeding betaine to rats fed the casein-, SB-, and SPI-based diets. Betaine-induced elevation of plasma cholesterol was decreased by feeding the SB-based diet compared with the casein-based diet, but was not decreased by feeding the SPI-based diet. In rats fed the SPI-based diet, the increased concentration of plasma cholesterol by betaine feeding was not prevented by independent addition of SL or SF, but was prevented by a combination of SL and SF, and was associated with increased fecal excretion of bile acids.

Barley ß-glucan reduces blood cholesterol levels via interrupting bile acid metabolism.

Underlying mechanisms responsible for the cholesterol-lowering effect of ß-glucan have been proposed, yet have not been fully demonstrated. The primary aim of this study was to determine whether the consumption of barley ß-glucan lowers cholesterol by affecting the cholesterol absorption, cholesterol synthesis or bile acid synthesis. In addition, this study was aimed to assess whether the underlying mechanisms are related to cholesterol 7α hydroxylase (CYP7A1) SNP rs3808607 as proposed by us earlier. In a controlled, randomised, cross-over study, participants with mild hypercholesterolaemia (n 30) were randomly assigned to receive breakfast containing 3 g high-molecular weight (HMW), 5 g low-molecular weight (LMW), 3 g LMW barley ß-glucan or a control diet, each for 5 weeks. Cholesterol absorption was determined by assessing the enrichment of circulating 13C-cholesterol over 96 h following oral administration; fractional rate of synthesis for cholesterol was assessed by measuring the incorporation rate of 2H derived from deuterium oxide within the body water pool into the erythrocyte cholesterol pool over 24 h; bile acid synthesis was determined by measuring serum 7α-hydroxy-4-cholesten-3-one concentrations. Consumption of 3 g HMW ß-glucan decreased total cholesterol (TC) levels (P=0·029), but did not affect cholesterol absorption (P=0·25) or cholesterol synthesis (P=0·14). Increased bile acid synthesis after consumption of 3 g HMW ß-glucan was observed in all participants (P=0·049), and more pronounced in individuals carrying homozygous G of rs3808607 (P=0·033). In addition, a linear relationship between log (viscosity) of ß-glucan and serum 7α-HC concentration was observed in homozygous G allele carriers. Results indicate that increased bile acid synthesis rather than inhibition of cholesterol absorption or synthesis may be responsible for the cholesterol-lowering effect of barley ß-glucan. The pronounced TC reduction in G allele carriers of rs3808607 observed in the previous study may be due to enhanced bile acid synthesis in response to high-viscosity ß-glucan consumption in those individuals.

Identification of Taurine-Responsive Genes in Murine Liver Using the Cdo1-Null Mouse Model.

The cysteine dioxygenase (Cdo1)-null mouse is unable to synthesize hypotaurine and taurine by the cysteine/cysteine sulfinate pathway and has very low taurine levels in all tissues. The lack of taurine is associated with a lack of taurine conjugation of bile acids, a dramatic increase in the total and unconjugated hepatic bile acid pools, and an increase in betaine and other molecules that serve as organic osmolytes. We used the Cdo1-mouse model to determine the effects of taurine deficiency on expression of proteins involved in sulfur amino acid and bile acid metabolism. We identified cysteine sulfinic acid decarboxylase (Csad), betaine:homocysteine methytransferase (Bhmt), cholesterol 7α-hydroxylase (Cyp7a1), and cytochrome P450 3A11 (Cyp3a11) as genes whose hepatic expression is strongly regulated in response to taurine depletion in the Cdo1-null mouse. Dietary taurine supplementation of Cdo1-null mice restored hepatic levels of these four proteins and their respective mRNAs to wild-type levels, whereas dietary taurine supplementation had no effect on abundance of these proteins or mRNAs in wild-type mice.

GATA4 Is Sufficient to Establish Jejunal Versus Ileal Identity in the Small Intestine.

BACKGROUND & AIMS: Patterning of the small intestinal epithelium along its cephalocaudal axis establishes three functionally distinct regions: duodenum, jejunum, and ileum. Efficient nutrient assimilation and growth depend on the proper spatial patterning of specialized digestive and absorptive functions performed by duodenal, jejunal, and ileal enterocytes. When enterocyte function is disrupted by disease or injury, intestinal failure can occur. One approach to alleviate intestinal failure would be to restore lost enterocyte functions. The molecular mechanisms determining regionally defined enterocyte functions, however, are poorly delineated. We previously showed that GATA binding protein 4 (GATA4) is essential to define jejunal enterocytes. The goal of this study was to test the hypothesis that GATA4 is sufficient to confer jejunal identity within the intestinal epithelium. METHODS: To test this hypothesis, we generated a novel Gata4 conditional knock-in mouse line and expressed GATA4 in the ileum, where it is absent. RESULTS: We found that GATA4-expressing ileum lost ileal identity. The global gene expression profile of GATA4-expressing ileal epithelium aligned more closely with jejunum and duodenum rather than ileum. Focusing on jejunal vs ileal identity, we defined sets of jejunal and ileal genes likely to be regulated directly by GATA4 to suppress ileal identity and promote jejunal identity. Furthermore, our study implicates GATA4 as a transcriptional repressor of fibroblast growth factor 15 (Fgf15), which encodes an enterokine that has been implicated in an increasing number of human diseases. CONCLUSIONS: Overall, this study refines our understanding of an important GATA4-dependent molecular mechanism to pattern the intestinal epithelium along its cephalocaudal axis by elaborating on GATA4's function as a crucial dominant molecular determinant of jejunal enterocyte identity. Microarray data from this study have been deposited into NCBI Gene Expression Omnibus (http://www.ncbi.nlm.nih.gov/geo) and are accessible through GEO series accession number GSE75870.

The antihypercholesterolemic effect of columbamine from Rhizoma Coptidis in HFHC-diet induced hamsters through HNF-4α/FTF-mediated CYP7A1 activation.

The aim of this study was to investigate the antihypercholesterolemic activity and potential molecular mechanism of columbamine (COL) that was prepared by extraction from Rhizoma Coptidis in hamsters and HepG2 cells. The results displayed that the COL from Rhizoma Coptidis was a safe natural compound with a LD50 0f 1524.6mg/kg and no detectable toxic symptoms during the observation of chronic toxicity. COL dose-dependently reversed the abnormal lipid levels induced by HFHC diet. Specifically, COL(M) and COL(H) significantly reduced the blood lipid levels(TC, TG and LDL-c) and enhanced the fecal contents of TBA by 21.8% and 25.1% respectively in hamsters. COL up-regulated the genes of CYP8B1, CYP7A1 and LDLR in mRNA and protein level, and down-regulated those of HMGCR to a different degree. Especially, CYP7A1 were significantly up-regulated by COL in hamsters (p<0.01). Further analysis indicated that COL obviously activated the mRNA and protein expression of the transcription factors FTF, HNF-4α, and inhibited those of SHP. Promoter luciferase assay showed that COL induced the expression of FTF and HNF-4α, further transactivating CYP7A1, which accelerated the conversion of liver cholesterol to bile acids. It concluded that the COL showed high lipid-lowering activities through indirectly transactivating CYP7A1 by upregulating FTF and HNF-4α, and directly activating CYP7A1 catalytic activity by strongly interacting with receptor and ligand, therefore promoting cholesterol catabolism and accelerating the excretion of bile acids.

Addition of Dexamethasone Alters the Bile Acid Composition by Inducing CYP8B1 in Primary Cultures of Human Hepatocytes.

BACKGROUND: Primary human hepatocytes offer the best human in vitro model for studies on human liver cell metabolism. Investigators use a variety of different media supplements and matrix biocoatings and the type of culture system used may influence the outcome. OBJECTIVES: To optimize in vitro conditions for primary human hepatocytes with regard to bile acid synthesis. METHODS: Human hepatocytes were isolated and cultured on collagen type I or EHS matrigel in cell media with or without dexamethasone. The glucocorticoid receptor (GR) antagonist RU486 was used to elucidate the involvement of GR. RESULTS: Hepatocytes cultured on EHS matrigel produced more bile acids and expressed higher levels of cholesterol 7α-hydroxylase (CYP7A1) than cells cultured on rat tail collagen. Supplementation with dexamethasone increased the formation of cholic acid (CA) and decreased chenodeoxycholic acid formation. In line with these results, the mRNA expression of sterol 12α-hydroxylase (CYP8B1) increased following dexamethasone treatment. Surprisingly, the mRNA expression of CYP7A1 and CYP27A1 was not increased to the same extent. By using the GR antagonist RU486, we concluded that CYP8B1 induction is mediated via a GR-independent pathway. An altered expression of retinoid-related orphan receptor (ROR) α and ROR α target gene Glucose-6-phosphatase (G6Pase) suggests that ROR α signaling may regulate CYP8B1 expression. CONCLUSION: Primary human hepatocytes have an increased bile acid synthesis rate when cultured on matrigel as compared to collagen. Exposure to glucocorticoid hormones stimulates the expression of CYP8B1, leading to an increased formation of CA and alteration of the bile acid composition. The effect is most likely mediated through a GR-independent pathway, possibly through ROR α.