QiShenYiQi pill inhibits atherosclerosis by promoting TTC39B-LXR mediated reverse cholesterol transport in liver.

BACKGROUND: Tetranucleotide repeat domain protein 39B (TTC39B) was found to combine with ubiquitin ligase E3, and promote the ubiquitination modification of liver X receptor (LXR), which led to the inhibition of reverse cholesterol transport and development of atherosclerosis. QiShenYiQi pill (QSYQ) is a modern Chinese patent drug for treating ischemic cardiovascular diseases, the underlying mechanism is found to promote the expression of LXR-α/ ATP-binding cassette transporter G5 (ABCG5) in the liver of atherosclerotic mice. PURPOSE: The aim of this study is to investigate the effect of QSYQ on TTC39B-LXR mediated reverse cholesterol transport in atherosclerotic mice. STUDY DESIGN AND METHODS: Male apolipoprotein E gene knockout mice (7 weeks old) were fed with high-fat diet and treated with low dose of QSYQ (QSYQ-l, 0.3 g/kg·d), high dose of QSYQ (QSYQ-H, 1.2 g/kg·d) and LXR-α agonist (LXR-A, GW3965 10 mg/kg·d) for 8 weeks. C57BL/6 J mice were fed with normal diet and used as negative control. Oil red O staining, HE staining, ELISA, RNA sequencing, western blot, immunohistochemistry, RT-PCR, cell culture and RNA interference were performed to analyze the effect of QSYQ on atherosclerosis. RESULTS: HE staining showed that QSYQ reduced the atherosclerotic lesion significantly when compared to the control group. ELISA measurement showed that QSYQ decreased serum VLDL and increased serum ApoA1. Oil Red O staining showed that QSYQ reduced the lipid content of liver and protect liver function. Comparative transcriptome RNA-sequence of liver showed that DEGs after QSYQ treatment enriched in high-density lipoprotein particle, ubiquitin ligase complex, bile secretion, etc. Immunohistochemical staining and western blot proved that QSYQ increased the protein expression of hepatic SR-B1, LXR-α, LXR-ß, CYP7A1 and ABCG5. Targeted inhibiting Ttc39b gene in vitro further established that QSYQ inhibited the gene expression of Ttc39b, increased the protein expression of SR-B1, LXR-α/ß, CYP7A1 and ABCG5 in rat hepatocyte. CONCLUSION: Our results demonstrated the new anti-atherosclerotic mechanism of QSYQ by targeting TTC39B-LXR mediated reverse cholesterol transport in liver. QSYQ not only promoted reverse cholesterol transport, but also improved fatty liver and protected liver function.

Efficacy of Lidan Tang on high-fat-diet induced hepatolithiasis in mice and possible mechanism.

OBJECTIVE: To investigate efficacy of Lidan Tang (LDT) on gallstone induced by high fat diet in mice, and to study its underlying mechanism. METHODS: Mice were fed with high fat diet every day and treated with LDT (9.01 times of human clinic dosage). Mice were randomly divided into 6 groups as control group, gallstone model group (high-fat diet), positive control ursodeoxycholic acid (UDCA) group (80 mg·kg-1·d-1, i.g.), LDT low dose group (6 kg/d, i.g.), LDT middle dose group (12 kg/d, i.g.), and LDT high dose group (24 kg/d, i.g.). The whole experiment was lasted for 4 weeks. The levels of ALT, AST, LDH, CHO, HDL-C and LDL-C in serum were measured, the pathological sections were observed by hematoxylin-eosin staining, the activities of antioxidant enzymes were measured by kits, and the proteins related to oxidative stress and lipid transport were detected by Western blot analysis. RESULTS: LDT could significantly reduce the contents of ALT and AST in serum and improve the pathological tissue of liver. LDT could significantly reduce the content of MDA and LPO, and increase the level of GSH and GSH-PX in liver tissue. The data of Western blot showed that LDT had antioxidant effect promoting Keap1/Nrf2 pathway and regulated the process of lipid transport, which was statistically significant. In addition, LDT treatment inhibited the expression of ATP-binding cassette transports ABCG5/8 in liver, and reduced cholesterol transport from the hepatocytes to the gallbladder. CONCLUSION: LDT has protective effect on gallstones induced by high fat diet in mice, which might be based on the protective effect on liver, including enhancing the antioxidant capacity of liver and reducing the production of lipid peroxides.

Dietary Betaine Addition Promotes Hepatic Cholesterol Synthesis, Bile Acid Conversion, and Export in Rats.

It is widely reported how betaine addition regulates lipid metabolism but how betaine affects cholesterol metabolism is still unknown. This study aimed to investigate the role of betaine in hepatic cholesterol metabolism of Sprague-Dawley rats. Rats were randomly allocated to four groups and fed with a basal diet or a high-fat diet with or without 1% betaine. The experiment lasted 28 days. The results showed that dietary betaine supplementation reduced the feed intake of rats with final weight unchanged. Serum low-density-lipoprotein cholesterol was increased with the high-fat diet. The high-fat diet promoted cholesterol synthesis and excretion by enhancing the HMG-CoA reductase and ABCG5/G8, respectively, which lead to a balance of hepatic cholesterol. Rats in betaine groups showed a higher level of hepatic total cholesterol. Dietary betaine addition enhanced cholesterol synthesis as well as conversion of bile acid from cholesterol by increasing the levels of HMGCR and CYP7A1. The high-fat diet decreased the level of bile salt export pump, while dietary betaine addition inhibited this decrease and promoted bile acid efflux and increased total bile acid levels in the intestine. In summary, dietary betaine addition promoted hepatic cholesterol metabolism, including cholesterol synthesis, conversion of bile acids, and bile acid export.

Conjugated Linoleic Acid and Alpha Linolenic Acid Improve Cholesterol Homeostasis in Obesity by Modulating Distinct Hepatic Protein Pathways.

SCOPE: High-fat diet (HFD)-induced obesity impairs macrophage-to-feces reverse cholesterol transport (RCT). It is hypothesized that dietary supplementation with the polyunsaturated fatty acids conjugated linoleic acid (CLA) or alpha linolenic acid (ALA) would prevent HFD-impaired RCT by modulating hepatic protein pathways. METHODS AND RESULTS: ApoE3L.CETP mice are fed a HFD supplemented ± CLA or ALA for 12 weeks and in vivo macrophage-to-feces RCT is determined. Hepatic cholesterol transporters and the hepatic proteome are assessed by immunoblotting and mass spectrometry, respectively. Mice fed HFD alone, but not ALA-HFD or CLA-HFD, exhibit increased systemic cholesterol levels, increased 3 H-cholesterol levels in plasma and liver but not feces during RCT, and reduced hepatic ABCG5/8 expression relative to LFD. ALA-HFD significantly reduces liver weight, hepatic cholesterol levels, and expression of the cholesterol synthesis enzyme farnesyl pyrophosphate synthase relative to HFD. ALA further increases the expression of acetyl-coA oxidase-associated proteins and suppress PPARα-induced proteins relative to HFD. CLA does not significantly attenuate hepatic lipid levels but is associated with reduced hepatic expression of fatty acid binding protein (FABP)-1/FABP4 levels relative to HFD, and reduced inflammatory pathway activation relative to ALA-HFD. CONCLUSION: ALA and CLA exert distinct mechanistic advantages on cholesterol homeostasis and RCT in obesity.

FMO3 and its metabolite TMAO contribute to the formation of gallstones.

Trimethylamine-N-oxide (TMAO) is a metabolite derived from trimethylamine (TMA), which is first produced by gut microbiota and then oxidized by flavin-containing monooxygenase 3 (FMO3) in the liver. TMAO may contribute to the development of diseases such as atherosclerosis because of its role in regulating lipid metabolism. In this study, we found that high plasma TMAO levels were positively associated with the presence of gallstone disease in humans. We further found increased hepatic FMO3 expression and elevated plasma TMAO level in a gallstone-susceptible strain of mice C57BL/6J fed a lithogenic diet (LD), but not in a gallstone-resistant strain of mice AKR/J. Dietary supplementation of TMAO or its precursor choline increased hepatic FMO3 expression and plasma TMAO levels and induced hepatic canalicular cholesterol transporters ATP binding cassette (Abc) g5 and g8 expression in mice. Up-regulation of ABCG5 and ABCG8 expression was observed in hepatocytes incubated with TMAO in vitro. Additionally, in AKR/J mice fed a LD supplemented with 0.3% TMAO, the incidence of gallstones rose up to 70% compared with 0% in AKR/J mice fed only a LD. This was associated with increased hepatic Abcg5 and g8 expression induced by TMAO. Our study demonstrated TMAO could be associated with increased hepatic Abcg5/g8 expression, biliary cholesterol hypersecretion and gallstone formation.

Fucoidan A2 from the Brown Seaweed Ascophyllum nodosum Lowers Lipid by Improving Reverse Cholesterol Transport in C57BL/6J Mice Fed a High-Fat Diet.

Reverse cholesterol transport (RCT) is a physiological process, in which excess peripheral cholesterol is transported to the liver and further excreted into the bile and then feces. Recently, fucoidans are reported to have a lipid-lowering effect. This study was designed to investigate whether fucoidan from the brown seaweed Ascophyllum nodosum lowers lipid by modulating RCT in C57BL/6J mice fed a high-fat diet. Our results indicated that fucoidan intervention significantly reduced plasma triglyceride, total cholesterol, and fat pad index and markedly increased high-density lipoprotein cholesterol in a dose-dependent manner. In the liver, fucoidan significantly increased the expression of peroxisome proliferator-activated receptor (PPAR)α, PPARγ, liver X receptor (LXR)ß, adenosine triphosphate (ATP) binding cassette (ABC)A1, ABCG8, low-density lipoprotein receptor (LDLR), scavenger receptor B type 1 (SR-B1), and cholesterol 7-α-hydroxylase A1 (CYP7A1) and decreased the triglyceride level and expression of proprotein convertase subtilisin/kexin type 9 (PCSK9) and PPARß but had no effect on LXRα, ABCG1, and ABCG5. In the small intestine, the fucoidan treatment significantly reduced the expression of Niemann-Pick C1-like 1 (NPC1L1) and improved ABCG5 and ABCG8. These results demonstrated that fucoidan can improve lipid transfer from plasma to the liver by activating SR-B1 and LDLR and inactivating PCSK9 and upregulate lipid metabolism by activating PPARα, LXRß, ABC transporters, and CYP7A1. In the small intestine, this fucoidan can decrease cholesterol absorption and increase cholesterol excretion by activating NPC1L1 and ABCG5 and ABCG8, respectively. In conclusion, fucoidan from A. nodosum may lower lipids by modulating RCT-related protein expression and can be explored as a potential compound for prevention or treatment of hyperlipidemia-related diseases.

Zingiber officinale extract administration diminishes steroyl-CoA desaturase gene expression and activity in hyperlipidemic hamster liver by reducing the oxidative and endoplasmic reticulum stress.

BACKGROUND: Stearoyl CoA desaturases (SCD) are enzymes that convert saturated to monounsaturated fatty acids and have increased activity in hepatic steatosis. PURPOSE: We aimed to investigate the potential of ginger extract (GIN) to modulate the liver SCD1 expression and activity in hyperlipidemic (HL) conditions, in order to lower lipid accumulation in the steatotic liver. STUDY DESIGN/METHODS: Male Golden Syrian hamsters were divided in three groups: (i) fed with standard chow (N), (ii) fed with standard chow plus 3% cholesterol and 15% butter for 21 weeks (HL), (iii) HL treated with GIN (800 µg/kg body weight/day) in the last 5 weeks of fat diet (HL-GIN). Cholesterol (C), triglycerides (TG), non-esterified fatty acids (NEFA), SCD1 estimated activity (C16:1n7/C16:0; C18:1n9/C18:0) and gene expression, acetyl-CoA carboxylase (ACC), thiobarbituric acid reactive substances (TBARS), paraoxonase1 (PON1) and myeloperoxidase (MPO) were determined in the plasma and liver of all hamsters. We measured protein expression of endoplasmic reticulum stress (ERS) markers, gene and protein expression of liver X receptor α/ß (LXRα/ß), peroxisome proliferator-activated receptor γ (PPARγ), ATP-binding cassette sub-family G member 5/8 (ABCG5/G8) and 7α-hydroxylase1 (CYP7A1) in all hamsters' livers. RESULTS: In plasma, in HL-GIN versus HL hamsters, SCD1 estimated activity was lower (27%; 15%, p < 0.05), NEFA levels decreased by 91%, p < 0.001, while C and TG levels did not vary; the oxidative stress expressed as MPO and TBARS levels decreased (15%; 11%, p < 0.01), while PON1 protein increased (75%, p < 0.05). In the liver of HL-GIN versus HL, C, TG, NEFA, MPO and TBARS levels decreased (8-40%, p < 0.05) and PON1 protein levels increased (30%, p < 0.05), SCD1 estimated activity decreased (8%; 9%, p < 0.05), in parallel with the reduced gene expression of SCD1 and ACC (70-80%, p < 0.05). The protein expression of the ERS sensors decreased (30-65%, p < 0.05), while that of ABCG5/G8, CYP7A1, LXRα/ß and PPARγ increased in HL-GIN (20-30%, p < 0.05) versus HL liver. CONCLUSION: GIN reduces SCD1 estimated activity and expression, as well as the lipids accumulated in the livers of HL hamsters. This is achieved through a mechanism involving the decrease of the oxidative and ERS, and the enhancement of cholesterol efflux.

Butyrate from pectin fermentation inhibits intestinal cholesterol absorption and attenuates atherosclerosis in apolipoprotein E-deficient mice.

Short-chain fatty acids (SCFAs), the major products of dietary fiber fermentation by intestinal microflora, exert beneficial effects on pathogenesis of multiple metabolic diseases. The aim of this study was to determine whether SCFAs from fermentation of pectin (PE), a soluble dietary fiber, prevent the development of atherosclerosis in apolipoprotein E-deficient (apoE-/-) mice. Male apoE-/- mice (8-week-old) were fed a high-fat, high-cholesterol diet (HCD; 21% wt/wt fat, 0.15% wt/wt cholesterol) or HCD supplemented with 20% wt/wt PE (HCD+PE) alone or with antibiotics (HCD+PE + A) in drinking water for 12 weeks. Serum lipids and SCFAs concentrations, atherosclerotic lesion area, and intestinal morphology and function were measured. Caco-2 cells were treated with SCFAs to determine whether they affected the expression of genes involved in cholesterol absorption. HCD+PE-treated mice exhibited decreased serum total and low-density lipoprotein cholesterol, and reduced atherosclerotic lesion area compared with HCD mice. These beneficial effects of PE were not observed in the HCD+PE+A group. Incubation of Caco-2 cells with butyrate, but not acetate and propionate, down-regulated the expression of Niemann-Pick C1-Like 1 but up-regulated the ATP-binding cassette transporters G5 and G8 (ABCG5 and G8) at the mRNA level. Butyrate treatment also increased transcriptional activity of liver X receptor in Caco-2 cells. Our data suggest that butyrate from PE intestinal fermentation protects mice from the progression of diet-induced atherosclerosis in apoE-/- mice. These findings suggest a novel mechanism by which dietary fiber may prevent the development of atherosclerosis.