This study aims to investigate the potential effect of the water extract of fresh Rehmanniae Radix on hypercholesterolemia in mice that was induced by a high-fat and high-cholesterol diet and explore its possible mechanism from bile acid reabsorption. Male C57BL/6 mice were randomly assigned into the following groups: control, model, low-and high-dose(4 and 8 g·kg~(-1), respectively) fresh Rehmanniae Radix, and positive drug(simvastatin, 0.05 g·kg~(-1)). Other groups except the control group were fed with a high-fat and high-cholesterol diet for 6 consecutive weeks to induce hypercholesterolemia. From the 6th week, mice were administrated with corresponding drugs daily via gavage for additional 6 weeks, while continuing to be fed with a high-fat and high-cholesterol diet. Serum levels of total cholesterol(TC), triglycerides(TG), low density lipoprotein-cholesterol(LDL-c), high density lipoprotein-cholesterol(HDL-c), and total bile acid(TBA), as well as liver TC and TG levels and fecal TBA level, were determined by commercial assay kits. Hematoxylin-eosin(HE) staining, oil red O staining, and transmission electron microscopy were performed to observe the pathological changes in the liver. Three livers samples were randomly selected from each of the control, model, and high-dose fresh Rehmanniae Radix groups for high-throughput transcriptome sequencing. Differentially expressed genes were mined and KEGG pathway enrichment analysis was performed to predict the key pathways and target genes of the water extract of fresh Rehmanniae Radix in the treatment of hypercholesterolemia. RT-qPCR was employed to measure the mRNA levels of cholesterol 7α-hydroxylase(CYP7A1) and cholesterol 27α-hydroxylase(CYP27A1) in the liver. Western blot was employed to determine the protein levels of CYP7A1 and CYP27A1 in the liver as well as farnesoid X receptor(FXR), apical sodium-dependent bile acid transporter(ASBT), and ileum bile acid-binding protein(I-BABP) in the ileum. The results showed that the water extract of fresh Rehmanniae Radix significantly lowered the levels of TC and TG in the serum and liver, as well as the level of LDL-c in the serum. Conversely, it elevated the level of HDL-c in the serum and TBA in feces. No significant difference was observed in the level of TBA in the serum among groups. HE staining, oil red O staining, and transmission electron microscopy showed that the water extract reduced the accumulation of lipid droplets in the liver. Further mechanism studies revealed that the water extract of fresh Rehmanniae Radix significantly down-regulated the protein levels of FXR and bile acid reabsorption-related proteins ASBT and I-BABP. Additionally, it enhanced CYP7A1 and CYP27A1, the key enzymes involved in bile acid synthesis. Therefore, it is hypothesized that the water extract of fresh Rehmanniae Radix may exert an anti-hypercholesterolemic effect by regulating FXR/ASBT/I-BABP signaling, inhibiting bile acid reabsorption, and increasing bile acid excretion, thus facilitating the conversion of cholesterol to bile acids.
Animals ; Male ; Bile Acids and Salts/metabolism* ; Mice, Inbred C57BL ; Mice ; Diet, High-Fat/adverse effects* ; Cholesterol/metabolism* ; Drugs, Chinese Herbal/administration & dosage* ; Hypercholesterolemia/genetics* ; Receptors, Cytoplasmic and Nuclear/genetics* ; Rehmannia/chemistry* ; Liver/drug effects* ; Humans ; Cholesterol 7-alpha-Hydroxylase/genetics* ; Plant Extracts

A targeted metabolomics study was conducted on the bile acid profiles in the liver and feces of rats induced by a high-fat diet and intervened by ginsenoside Rb_1, along with the detection of FXR pathway gene expression in the liver, to explore and clarify its mechanism of action. The content of biochemical indicators in the serum were detected using an automatic biochemical analyzer. Hematoxylin and eosin(HE) staining and oil red O staining were used to detect pathological changes and lipid deposition in the liver. RT-PCR was used to detect the mRNA expression of FXR, small heterodimer partner(SHP), cholesterol 7 alpha-hydroxylase(CYP7A1), and sterol regulatory element-binding protein-1c(SREBP-1c) in the liver. Targeted bile acid metabolomics technology was employed to analyze changes in bile acid profiles in liver tissue and feces, and a correlation analysis was performed between key genes such as FXR, SHP, CYP7A1, SREBP-1c and differential bile acid metabolites. The results showed that ginsenoside Rb_1 significantly reduced the levels of total cholesterol(TC), triglycerides(TG), low-density lipoprotein cholesterol(LDL-C), and high-density lipoprotein cholesterol(HDL-C) in the serum, alleviated the large fat vacuoles and lipid deposition in the liver, increased the expression of FXR mRNA in the liver, and decreased the expression of SREBP-1c mRNA. The expression of CYP7A1 and SHP mRNA was increased, but the differences were not statistically significant. Targeted bile acid metabolomics showed that ginsenoside Rb_1 could restore the levels of 9 bile acids in the liver and 8 bile acids in the feces. Ginsenoside Rb_1 also increased the percentage of taurocholic acid(TCA) in the liver(56.78%) and the percentage of 12-ketolithocholic acid(12-KLCA) in the feces(26.10%). Pathway enrichment analysis revealed two pathways involved in bile acid metabolism: primary bile acid biosynthesis and taurine and hypotaurine metabolism. Correlation analysis showed that FXR, SHP, CYP7A1, and SREBP-1c were positively correlated with multiple differential bile acids. These results suggest that ginsenoside Rb_1 may intervene in lipid metabolism disorders induced by a high-fat diet by regulating the FXR pathway and modulating bile acid profiles in the liver and feces.
Animals ; Bile Acids and Salts/metabolism* ; Rats ; Ginsenosides/pharmacology* ; Male ; Receptors, Cytoplasmic and Nuclear/genetics* ; Liver/drug effects* ; Diet, High-Fat/adverse effects* ; Metabolomics ; Rats, Sprague-Dawley ; Feces/chemistry* ; Cholesterol 7-alpha-Hydroxylase/metabolism* ; Sterol Regulatory Element Binding Protein 1/genetics* ; Humans

Farnesoid X receptor (FXR) is a member of the nuclear receptor superfamily of ligand-activated transcription factors. As a metabolic regulator, FXR plays key roles in bile acid and cholesterol metabolism and lipid and glucose homeostasis. Therefore, FXR is a potential drug target for several metabolic syndromes, especially those related to lipidemia disorders. In the present study, we identified small molecule SIPI-7623, a derivative of an extract from Oriental wormwood (Artemisia capillaris), and found that it specifically upregulated the expression of cholesterol-7-alpha-hydroxylase (CYP7A1), downregulated the expression of sterol-regulatory element-binding protein 1c (SREBP-1c) in the liver, and inhibited the expression of ileal bile acid binding-protein (IBABP) in the ileum of rats. We found that inhibition of FXR by SIPI-7623 decreased the level of cholesterol and triglyceride. SIPI-7623 reduced the levels of cholesterol and triglyceride in in vitro HepG2 cell models, ameliorated diet-induced atherosclerosis, and decreased the serum lipid content on rats and rabbits model of atherosclerosis in vivo. Furthermore, SIPI-7623 decreased the extent of atherosclerotic lesions. Our resutls demonstrated that antagonism of the FXR pathway can be employed as a therapeutic strategy to treat metabolic diseases such as hyperlipidemia and atherosclerosis. In conclusion, SIPI-7623 could be a promising lead compound for development of drugs to treat hyperlipidemia and atherosclerosis.
Animals ; Artemisia ; chemistry ; Atherosclerosis ; drug therapy ; genetics ; metabolism ; Cholesterol ; metabolism ; Cholesterol 7-alpha-Hydroxylase ; genetics ; metabolism ; Drugs, Chinese Herbal ; administration & dosage ; Humans ; Hyperlipidemias ; drug therapy ; genetics ; metabolism ; Hypolipidemic Agents ; administration & dosage ; Liver ; drug effects ; metabolism ; Male ; Rabbits ; Rats ; Rats, Sprague-Dawley ; Receptors, Cytoplasmic and Nuclear ; antagonists & inhibitors ; genetics ; metabolism ; Sterol Regulatory Element Binding Protein 1 ; genetics ; metabolism ; Triglycerides ; metabolism

To study the effect of cholesterol and 25-OH-cholesterol on cholesterol metabolism in HepG2 cells and the effect of coptisine (Cop) extracted from Coptidis Rhizoma (CR) in reducing and regulating cholesterol. In this study, TC, TG, LDL-c and HDL-c were measured by biochemical analysis; mRNA and protein expressions of LDLR, HMGCR and CYP7A1 were detected by qRT-PCR and Western blot. According to the results, cholesterol and 25-OH-cholesterol inducing could decrease in mRNA and protein expressions of LDLR and CYP7A1, so as to increase TC and LDL-c contents. However, Cop could up-regulate mRNA and protein expressions of LDLR and CYP7A1 and down-regulate that of HMGCR, so as to reduce TC and LDL-c levels. These findings suggested that Cop has potential pharmacological activity for reducing cholesterol, and may reduce cholesterol by regulating mRNA and protein expressions of key genes involved in cholesterol metabolism, such as LDLR, CYP7A1 and HMGCR. This study laid a firm theoretical foundation for developing new natural drugs with the cholesterol-lowering activity.
Berberine ; analogs & derivatives ; pharmacology ; Cholesterol ; metabolism ; Cholesterol 7-alpha-Hydroxylase ; genetics ; metabolism ; Drugs, Chinese Herbal ; pharmacology ; Gene Expression Regulation, Enzymologic ; drug effects ; Hep G2 Cells ; Humans ; Hydroxymethylglutaryl CoA Reductases ; genetics ; metabolism ; Receptors, LDL ; genetics ; metabolism ; Triglycerides ; metabolism

Cholesterol 7alpha-hydroxylase (CYP7A1) regulates the balance between cholesterol supply and metabolism by catalyzing the rate-limiting step of bile acid biosynthesis. The transcriptional activity of CYP7A1 is tightly controlled by various nuclear receptors. A forkhead transcription factor O1 (FOXO1) plays a critical role in metabolism, and insulin inactivates FOXO1 through Akt-dependent phosphorylation and nuclear exclusion. We investigated the role of insulin-Akt-FOXO1 signaling pathway in CYP7A1 transcriptional regulation since we found putative insulin-response elements, FOXO1 binding sequences, in both rat and human CYP7A1 promoters. However, ectopic expression of FOXO1 increased the rat CYP7A1-, but mildly reduced human CYP7A1-promoter activities in a dose-dependent manner. Similarly to bile acids, insulin treatment increased small heterodimer partner (SHP) mRNA rapidly and transiently, leading to the suppression of CYP7A1 transcription in both human and rodents. Chromatin immunoprecipitation showed that FOXO1 directly bound to rat CYP1A1 promoter in the absence of insulin. FOXO1 binding to the rat promoter was diminished by insulin treatment as well as by expression of SHP. Our results suggest that the stimulation of insulin- signaling pathway of Akt-FOXO1 and SHP expression may regulate cholesterol/bile acid metabolisms in liver, linking carbohydrate and cholesterol metabolic pathways. A prolonged exposure of insulin in hyperinsulinemic insulin resistance or diabetic status represses CYP7A1 transcription and bile acid biosynthesis through SHP induction and FOXO1 inactivation, leading to impairment of the hepatic cholesterol/bile acid metabolisms.
Animals ; Bile Acids and Salts/metabolism ; Cholesterol/*metabolism ; Cholesterol 7-alpha-Hydroxylase/genetics/*metabolism ; Forkhead Transcription Factors/genetics/*metabolism ; Gene Expression Regulation/drug effects ; Glucose/*metabolism ; Hep G2 Cells ; Humans ; Insulin/pharmacology ; Lipid Metabolism/drug effects ; Liver/*metabolism/pathology ; Mice ; Mice, Inbred C57BL ; Mutagenesis, Site-Directed ; Nerve Tissue Proteins/genetics/*metabolism ; Protein Binding/drug effects/genetics ; Proto-Oncogene Proteins c-akt/metabolism ; Rats ; Receptors, Cytoplasmic and Nuclear/genetics/metabolism ; Sequence Deletion/genetics ; Signal Transduction/drug effects/genetics ; Transcriptional Activation/drug effects/genetics

Cholesterol 7alpha-hydroxylase (CYP7A1) regulates the balance between cholesterol supply and metabolism by catalyzing the rate-limiting step of bile acid biosynthesis. The transcriptional activity of CYP7A1 is tightly controlled by various nuclear receptors. A forkhead transcription factor O1 (FOXO1) plays a critical role in metabolism, and insulin inactivates FOXO1 through Akt-dependent phosphorylation and nuclear exclusion. We investigated the role of insulin-Akt-FOXO1 signaling pathway in CYP7A1 transcriptional regulation since we found putative insulin-response elements, FOXO1 binding sequences, in both rat and human CYP7A1 promoters. However, ectopic expression of FOXO1 increased the rat CYP7A1-, but mildly reduced human CYP7A1-promoter activities in a dose-dependent manner. Similarly to bile acids, insulin treatment increased small heterodimer partner (SHP) mRNA rapidly and transiently, leading to the suppression of CYP7A1 transcription in both human and rodents. Chromatin immunoprecipitation showed that FOXO1 directly bound to rat CYP1A1 promoter in the absence of insulin. FOXO1 binding to the rat promoter was diminished by insulin treatment as well as by expression of SHP. Our results suggest that the stimulation of insulin- signaling pathway of Akt-FOXO1 and SHP expression may regulate cholesterol/bile acid metabolisms in liver, linking carbohydrate and cholesterol metabolic pathways. A prolonged exposure of insulin in hyperinsulinemic insulin resistance or diabetic status represses CYP7A1 transcription and bile acid biosynthesis through SHP induction and FOXO1 inactivation, leading to impairment of the hepatic cholesterol/bile acid metabolisms.
Animals ; Bile Acids and Salts/metabolism ; Cholesterol/*metabolism ; Cholesterol 7-alpha-Hydroxylase/genetics/*metabolism ; Forkhead Transcription Factors/genetics/*metabolism ; Gene Expression Regulation/drug effects ; Glucose/*metabolism ; Hep G2 Cells ; Humans ; Insulin/pharmacology ; Lipid Metabolism/drug effects ; Liver/*metabolism/pathology ; Mice ; Mice, Inbred C57BL ; Mutagenesis, Site-Directed ; Nerve Tissue Proteins/genetics/*metabolism ; Protein Binding/drug effects/genetics ; Proto-Oncogene Proteins c-akt/metabolism ; Rats ; Receptors, Cytoplasmic and Nuclear/genetics/metabolism ; Sequence Deletion/genetics ; Signal Transduction/drug effects/genetics ; Transcriptional Activation/drug effects/genetics

OBJECTIVETo study the expressions of FXR, PPARa and Bile acid metabolism related genes in intrahepatic cholestasis of pregnant rats.

METHODS60 clean SD pregnant rats were selected and divided randomly into three groups. Since the 13th day of pregnancy rats in control group were injected subcutaneously with refined vegetable oil 2.0 mg/kg/d Rats in no-treated group were injected subcutaneously with the 17-a-ethynylestradiol (EE) 1.25 mg/kg/d until the 17th day. Those rat ih treated group were injected subcutaneously with the 17-a-ethynylestradiol (EE) 1.25 mg/kg/d until the 17th day and then were treated with fenofibrate for another four days until the 21th day. All rats were killed at the 21th day and livers were collected for study. The levels of serum TBA were examined by ELISA. The mRNA expressions of PPARa, FXR, CYP7A1, CYP27A1 and CYP8B1 were examined by real-time PCR. (1)

RESULTSThe levels of TBA were significantly higher in no-treated group (68.7+/-4.2)mumol/L and treated group (69.5+/-3.8)mumol/L compared with that of control group (26.6+/-2.3)mumol/L at the 17th day (P value is less than 0.05) and no difference found between treated and no-treated groups (P value is more than 0.05). The levels of TBA were higher in no-treated group (69.4+/-3.7)mumol/L and treated group (48.5+/-4.8)mumol/L as compared to control group (27.1+/-3.2)mumol/L at the 21th day (P value is less than 0.05). The lever of TBA was significantly lower in Treated group compared with No-treated group (P value is less than 0.05). (2) The mRNA expressions of CYP7A1, FXR, CYP27A1 and CYP8B1 increased in No-treated group (1.55+/-0.03, 1.75+/-0.02, 2.45+/-0.01, 2.15+/-0.01, respectively) and were all higher as compared to control group (0.75+/-0.02, 1.25+/-0.03, 0.65+/-0.03, 1.50+/-0.02, respectively) (P value is less than 0.05). However, the mRNA expression of PPARa decreased in No-treated group (0.85+/-0.02) compared with control group (1.45+/-0.02) (P value is less than 0.05). The mRNA expressions of CYP27A1, PPARa and CYP8B1 increased in treated group (1.25+/-0.01, 1.65+/-0.05, 1.65+/-0.02, respectively) and were all higher than that of control group (P value is less than 0.05).

CONCLUSIONAbnormal expressions of CYP7A1, FXR, CYP27A1, CYP8B1 and PPARa may play a role in pathogenesis of estrogen-induced intrahepatic cholestasis. Activator of PPARa may be used as therapeutical drug for ICP.

Animals ; Bile Acids and Salts ; metabolism ; Cholestasis, Intrahepatic ; chemically induced ; metabolism ; pathology ; Cholesterol 7-alpha-Hydroxylase ; metabolism ; Ethinyl Estradiol ; administration & dosage ; Female ; PPAR alpha ; metabolism ; Pregnancy ; Pregnancy Complications ; chemically induced ; metabolism ; pathology ; RNA, Messenger ; genetics ; Rats ; Rats, Sprague-Dawley ; Receptors, Cytoplasmic and Nuclear ; genetics

Cajanus cajan L. is a natural plant, which contains a lot of potential active components. In the present study, we identified the effects of the stilbene extract from Cajanus cajan L. (sECC) on hepatic cholesterol metabolism in diet-induced (for 4 weeks) hyperlipidemic Kunming mice. All experimental mice were divided into 5 groups: control group, high lipid model group, sECC-treated with 200 or 100 mg kg(-1), and simvastatin (Sim, 12 mg kg(-1)) treated group. The mice were fed with fat and cholesterol-enriched chow except control mice that were fed with standard diet. The effects of sECC were investigated by monitoring serum and liver lipid profile (i. e. cholesterol homeostasis) in mice. To further explore the mechanism of sECC, hepatic cholesterol 7alpha-hydroxylase (CYP7A1) and low density lipoprotein (LDL) receptor expressions in cholesterol homeostasis were analyzed by reverse transcription PCR. After 4 weeks pretreatment, the mice in the high lipid model group showed markedly higher serum and hepatic lipid contents than control group (P< 0.01). Compared with high lipid model group, the increased serum and hepatic lipid contents were markedly attenuated by sECC (200 mg kg(-1)), the serum and hepatic total cholesterol were reduced by 31.5% and 22.7% (P<0.05), respectively. The triglyceride contents of serum and liver were also lowered by 23.0% and 14.4%, respectively. At the same times, serum LDL cholesterol decreased by 53.0% (P<0.01). The mRNA expressions of hepatic CYP7A1 and LDL-receptor were significantly enhanced in the mice administered with sECC (200 mg kg(-1)), whereas those expressions were suppressed by the fat and cholesterol-enriched diet. These data indicate that sECC reduces the atherogenic properties of dietary cholesterol in mice. It is indicated that expression enhancement of hepatic LDL-receptor and cholesterol 7alpha-hydroxylase may be responsible for the hypercholesterolemic effect.
Animals ; Anticholesteremic Agents ; isolation & purification ; pharmacology ; Body Weight ; drug effects ; Cajanus ; chemistry ; Cholesterol ; blood ; metabolism ; Cholesterol 7-alpha-Hydroxylase ; biosynthesis ; genetics ; Cholesterol, LDL ; blood ; Drugs, Chinese Herbal ; isolation & purification ; pharmacology ; Gene Expression Regulation ; Hypercholesterolemia ; blood ; genetics ; metabolism ; pathology ; Liver ; metabolism ; pathology ; Male ; Mice ; Organ Size ; drug effects ; Plant Leaves ; chemistry ; Plants, Medicinal ; chemistry ; RNA, Messenger ; metabolism ; Receptors, LDL ; biosynthesis ; genetics ; Stilbenes ; isolation & purification ; pharmacology ; Triglycerides ; blood ; metabolism

OBJECTIVETo investigate the cholesterol 7alpha-hydroxylase gene -204A/C polymorphism and its relationship with serum lipids and apolipoproteins (apo) levels in patients with endogenous hypertriglyceridemia (HTG) in Chinese population in Chengdu area.

METHODSThe genotype and allele frequencies of cholesterol 7alpha-hydroxylase gene -204A/C polymorphism were analyzed by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP). Serum lipids were measured by enzymatic kits and apolipoproteins AI, AII, B100, CII, CIII and E were measured by the RID kits in 132 HTG patients and 212 control subjects.

RESULTSAllele frequencies of A and C were 0.602 and 0.398 in HTG group and 0.601 and 0.399 in control group, respectively. There was no significant difference of allele and genotypes frequencies between HTG and control groups (P> 0.05). In HTG group, carriers with the genotypes CC and AC were associated with significantly higher concentrations of triglycerides and apoCIII compared with those with genotype AA (P< 0.05). In the control group, carriers with the genotypes CC and AC were associated with significantly lower serum high density lipoprotein cholesterol (HDL-C) level compared with those with genotype AA (P< 0.05). In the male control group, carriers with the genotypes CC and AC had elevated levels of serum triglycerides than those with genotype AA (P< 0.05).

CONCLUSIONThese results suggest that -204A/C polymorphism in the CYP7A1 gene does not relate with HTG but may has an effect on serum triglyceride and apoCIII levels in patients with endogenous HTG, the serum HDL-C level in control subjects and the serum TG level in male control subjects.

Adult ; Asian Continental Ancestry Group ; genetics ; China ; Cholesterol 7-alpha-Hydroxylase ; genetics ; Female ; Gene Frequency ; Genotype ; Humans ; Hypertriglyceridemia ; blood ; ethnology ; genetics ; Lipids ; blood ; Male ; Middle Aged ; Polymerase Chain Reaction ; Polymorphism, Genetic ; genetics ; Polymorphism, Restriction Fragment Length

BACKGROUNDGenetic factors account for approximately 50% of the individual variation in plasma low-density lipoprotein cholesterol (LDL-C) concentrations in the general population. Several candidate genes have been proposed but their relative contributions to the variance in LDL-C are not known, except for apolipoprotein E (apoE). We report here an investigation of the relationship between LDL-C and cholesterol 7alpha-hydroxylase (CYP7), as well as apoE and low-density lipoprotein receptor (LDLR), three pivotal genes in LDL metabolism.

METHODSOur study population included more than 200 nuclear families with increased coronary heart disease (CHD) risk from the National Heart, Lung, and Blood Institute (NHLBI) Family Heart Study. Variance-component linkage methods, a measured genotype approach, and a variance-component linkage analysis conditional on a measured genotype association were used.

RESULTSThe results showed significant linkage between a genetic determinant of plasma LDL-C concentrations and a polymorphism near CYP7 with its allelic variation accounting for 27% of the total LDL-C variation. There is significant association between plasma LDL-C concentrations and apoE genotypes. Conditional on the apoE association, the total LDL-C variation accounted by allelic variation of a polymorphism near CYP7 was increased significantly.

CONCLUSIONOur results suggest the apoE and CYP7 may be two important genes accounting for the genetic variation of plasma LDL-C concentrations in a population with cardiovascular diseases.

Adult ; Aged ; Alleles ; Apolipoproteins E ; genetics ; Cholesterol 7-alpha-Hydroxylase ; genetics ; Cholesterol, LDL ; blood ; Coronary Disease ; genetics ; Female ; Genetic Linkage ; Genetic Variation ; Genotype ; Humans ; Male ; Middle Aged ; Polymorphism, Genetic ; Receptors, LDL ; genetics ; Risk Factors