MaiJiTong granule attenuates atherosclerosis by reducing ferroptosis via activating STAT6-mediated inhibition of DMT1 and SOCS1/p53 pathways in LDLR-/- mice.

BACKGROUND AND PURPOSE: Atherosclerosis is the primary pathological basis of cardiovascular disease. Ferroptosis is a regulated form of cell death, a process of lipid peroxidation driven by iron, which can initiate and promote atherosclerosis. STAT6 is a signal transducer that shows a potential role in regulating ferroptosis, but, the exact role in ferroptosis during atherogenesis remains unclear. The Traditional Chinese Medicine Maijitong granule (MJT) is used for treating cardiovascular disease and shows a potential inhibitory effect on ferroptosis. However, the antiatherogenic effect and the underlying mechanism remain unclear. In this study, we determined the role of STAT6 in ferroptosis during atherogenesis, investigated the antiatherogenic effect of MJT, and determined whether its antiatherogenic effect was dependent on the inhibition of ferroptosis. METHODS: 8-week-old male LDLR-/- mice were fed a high-fat diet (HFD) at 1st and 10th week, respectively, to assess the preventive and therapeutic effects of MJT on atherosclerosis and ferroptosis. Simultaneously, the anti-ferroptotic effects and mechanism of MJT were determined by evaluating the expression of genes responsible for lipid peroxidation and iron metabolism. Subsequently, we reanalyzed microarray data in the GSE28117 obtained from cells after STAT6 knockdown or overexpression and analyzed the correlation between STAT6 and ferroptosis. Finally, the STAT6-/- mice were fed HFD and injected with AAV-PCSK9 to validate the role of STAT6 in ferroptosis during atherogenesis and revealed the antiatherogenic and anti-ferroptotic effect of MJT. RESULTS: MJT attenuated atherosclerosis by reducing plaque lesion area and enhancing plaque stability in both preventive and therapeutic groups. MJT reduced inflammation via suppressing inflammatory cytokines and inhibited foam cell formation by lowering the LDL level and promoting ABCA1/G1-mediated lipid efflux. MJT ameliorated the ferroptosis by reducing lipid peroxidation and iron dysregulation during atherogenesis. Mechanistically, STAT6 negatively regulated ferroptosis by transcriptionally suppressing SOCS1/p53 and DMT1 pathways. MJT suppressed the DMT1 and SOCS1/p53 via stimulating STAT6 phosphorylation. In addition, STAT6 knockout exacerbated atherosclerosis and ferroptosis, which abolished the antiatherogenic and anti-ferroptotic effects of MJT. CONCLUSION: STAT6 acts as a negative regulator of ferroptosis and atherosclerosis via transcriptionally suppressing DMT1 and SOCS1 expression and MJT attenuates atherosclerosis and ferroptosis by activating the STAT6-mediated inhibition of DMT1 and SOCS1/p53 pathways, which indicated that STAT6 acts a novel promising therapeutic target to ameliorate atherosclerosis by inhibiting ferroptosis and MJT can serve as a new therapy for atherosclerosis treatment.

Curcuma wenyujin rhizomes extract ameliorates lipid accumulation.

Curcuma wenyujin (C. wenyujin) is a medicinal plant that is traditionally used to treat blood stagnation, liver fibrosis, pain, and jaundice. In this study, we examined the effect of C. wenyujin rhizome extract on hepatic lipid accumulation both in vivo and in vitro. We found that the petroleum ether fraction of C. wenyujin rhizome extract (CWP) considerably reduced the accumulation of lipids in HepG2 cells treated with oleic and palmitic acid. Ultra-high-performance liquid chromatography coupled with LTQ-Orbitrap mass spectrometry was used to analyze the main chemical constituents of CWP, and 21 sesquiterpenes were identified. In vivo experiments revealed that the administration of CWP significantly reduced the body weight and serum total cholesterol (TC) level of low-density-lipoprotein receptor knockout mice treated with a high-fat diet without affecting their food intake. CWP also significantly reduced the levels of liver TC, liver triglycerides, aspartate transaminase, and alanine transaminase. Histological examination revealed that CWP dose-dependently reduced steatosis in liver tissue, significantly downregulated the expression of lipogenesis genes, and increased the ß-oxidation of fatty acids. CWP also significantly increased autophagy-related proteins. In conclusion, CWP rich in sesquiterpenes reduces the accumulation of lipids in vivo and in vitro by improving lipid metabolism and activating autophagy.

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.

Sophora tonkinensis and active compounds inhibit mitochondrial impairments, inflammation, and LDLR deficiency in myocardial ischemia mice through regulating the vesicle-mediated transport pathway.

Ancient Chinese medicine literature and modern pharmacological studies show that Sophora tonkinensis Gagnep. (ST) has a protective effect on the heart. A biolabel research based on omics and bioinformatics and experimental validation were used to explore the application value of ST in the treatment of heart diseases. Therapeutic potential, mechanism of action, and material basis of ST in treating heart diseases were analyzed by proteomics, metabolomics, bioinformatics, and molecular docking. Cardioprotective effects and mechanisms of ST and active compounds were verified by echocardiography, HE and Masson staining, biochemical analysis, and ELISA in the isoproterenol hydrochloride-induced myocardial ischemia (MI) mice model. The biolabel research suggested that the therapeutic potential of ST for MI may be particularly significant among the heart diseases it may treat. In the isoprenaline hydrochloride-induced MI mice model, ST and its five active compounds (caffeic acid, gallic acid, betulinic acid, esculetin, and cinnamic acid) showed significant protective effects against echocardiographic changes and histopathological damages of the ischemic myocardial tissue. Meanwhile, they showed a tendency to correct mitochondrial structure and function damage and the abnormal expression of 12 biolables (DCTN1, DCTN3, and SCARB2, etc.) in the vesicle-mediated transport pathway, inflammatory cytokines (IL-1ß, IL-6, and IL-10, etc.), and low density lipoprotein receptor (LDLR). The biolabel research identifies a new application value of ST in the treatment of heart diseases. ST and its active compounds inhibit mitochondrial impairments, inflammation, and LDLR deficiency through regulating the vesicle-mediated transport pathway, thus achieving the purpose of treating MI.

Confounding Effects of Tamoxifen: Cautionary and Practical Considerations for the Use of Tamoxifen-Inducible Mouse Models in Atherosclerosis Research-Brief Report.

BACKGROUND: In recent years, fate-mapping lineage studies in mouse models have led to major advances in vascular biology by allowing investigators to track specific cell populations in vivo. One of the most frequently used lineage tracing approaches involves tamoxifen-inducible CreERT-LoxP systems. However, tamoxifen treatment can also promote effects independent of Cre recombinase activation, many of which have not been fully explored. METHODS: To elucidate off-target effects of tamoxifen, male and female mice were either unmanipulated or injected with tamoxifen or corn oil. All mice received PCSK9 (proprotein convertase subtilisin/kexin type 9)-AAV (adeno-associated virus) injections and a modified Western diet to induce hypercholesterolemia. After 2 weeks, serum cholesterol and liver morphology were assessed. To determine the duration of any tamoxifen effects in long-term atherosclerosis experiments, mice received either 12 days of tamoxifen at baseline or 12 days plus 2 sets of 5-day tamoxifen boosters; all mice received PCSK9-AAV injections and a modified Western diet to induce hypercholesterolemia. After 24 weeks, serum cholesterol and aortic sinus plaque burden were measured. RESULTS: After 2 weeks of atherogenic treatment, mice injected with tamoxifen demonstrated significantly reduced serum cholesterol levels compared with uninjected- or corn oil-treated mice. However, there were no differences in PCSK9-mediated knockdown of LDL (low-density lipoprotein) receptors between the groups. Additionally, tamoxifen-treated mice exhibited significantly increased hepatic lipid accumulation compared with the other groups. Finally, the effects of tamoxifen remained for at least 8 weeks after completion of injections, with mice demonstrating persistent decreased serum cholesterol and impaired atherosclerotic plaque formation. CONCLUSIONS: In this study, we establish that tamoxifen administration results in decreased serum cholesterol, decreased plaque formation, and increased hepatic lipid accumulation. These alterations represent significant confounding variables in atherosclerosis research, and we urge future investigators to take these findings into consideration when planning and executing their own atherosclerosis experiments.

Tilianin improves lipid profile and alleviates atherosclerosis in ApoE-/- mice through up-regulation of SREBP2-mediated LDLR expression.

BACKGROUND: The huge global burden of atherosclerotic cardiovascular diseases (CVDs) represents an urgent unmet need for the development of novel therapeutics. Dracocephalum moldavica L. has been used as a traditional Uygur medicine to treat various CVDs for centuries. Tilianin is a major flavonoid component of D. moldavica L. and has potential for preventing atherosclerosis. However, the molecular mechanisms that tilianin attenuate atherosclerosis are far from fully understood. PURPOSES: The purpose of this study is to investigate the efficiency and underlying mechanisms of tilianin in controlling lipid profile and preventing atherogenesis. METHODS: The lipid-lowering effect of tilianin was evaluated in C57BL/6 and ApoE-/- mice by systematically determining serum biochemical parameters. The effects of tilianin on the atherosclerotic lesion were observed in aortic roots and whole aortas of ApoE-/- mice with oil red O staining. Caecal content from ApoE-/- mice were collected for 16S rRNA gene sequence analysis to assess the structure of the gut microbiota. The inhibition of hepatosteatosis was verified by histological examination, and a liver transcriptome analysis was performed to elucidate the tilianin-induced hepatic transcriptional alterations. Effects of tilianin on the expression and function of LDLR were examined in HepG2 cells and ApoE-/- mice. Further mechanisms underlying the efficacy of tilianin were investigated in HepG2 cells. RESULTS: Tilianin treatment improved lipid profiles in C57BL/6 and dyslipidemic ApoE-/- mice, especially reducing the serum LDL-cholesterol (LDL-C) level. Significant reductions of atherosclerotic lesion area and hepatosteatosis were observed in tilianin-treated ApoE-/- mice. The altered gut microbial composition in tilianin groups was associated with lipid metabolism and atherosclerosis. The liver transcriptome revealed that tilianin regulated the transcription of lipid metabolism-related genes. Then both in vitro and in vivo analyses revealed the potent effect of tilianin to enhance hepatic LDLR expression and its mediated LDL-C uptake. Further studies confirmed a critical role of SREBP2 in hepatic LDLR up-regulation by tilianin via increasing precursor and thus mature nuclear SREBP2 level. CONCLUSION: This study demonstrated the lipid-lowering effect of tilianin through SREBP2-mediated transcriptional activation of LDLR. Our findings reveal a novel anti-atherosclerotic mechanism of tilianin and underlie its potential clinical use in modulating CVDs with good availability and affordability.

Silencing YY1 Alleviates Ox-LDL-Induced Inflammation and Lipid Accumulation in Macrophages through Regulation of PCSK9/ LDLR Signaling.

The formation of macrophage foam cells stimulated by oxidized low-density lipoprotein (ox-LDL) is deemed an important cause of atherosclerosis. Transcription factor Yin Yang 1 (YY1), which is a universally expressed multifunctional protein, is closely related to cell metabolism disorders such as lipid metabolism, sugar metabolism, and bile acid metabolism. However, whether YY1 is involved in macrophage inflammation and lipid accumulation still remains unknown. After mouse macrophage cell line RAW264.7 cells were induced by ox-LDL, YY1 and proprotein convertase subtilisin/kexin type 9 (PCSK9) expressions were found to be increased while low-density lipoprotein receptor (LDLR) expression was lowly expressed. Subsequently, through reverse transcription-quantitative polymerase chain reaction (RT-qPCR), Western blot analysis, Oil Red O staining and cholesterol quantification, it turned out that silencing of YY1 attenuated the inflammatory response and lipid accumulation in RAW264.7 cells caused by ox-LDL. Moreover, results from the JASPAR database, chromatin immunoprecipitation (ChIP) assay, luciferase reporter assay and Western blot analysis suggested that YY1 activated PCSK9 by binding to PCSK9 promoter and modulated the expression of LDLR in the downstream of PCSK9. In addition, the results of functional experiments demonstrated that the inhibitory effects of YY1 interference on ox-LDL-mediated macrophage inflammation and lipid accumulation were reversed by PCSK9 overexpression. To sum up, YY1 depletion inhibited its activation of PCSK9, thereby reducing cellular inflammatory response, cholesterol homeostasis imbalance, and lipid accumulation caused by ox-LDL.

Novel triterpenoids from Alisma plantago-aquatica with influence on LDL uptake in HepG2 cells by inhibiting PCSK9.

BACKGROUND: Proprotein convertase subtilisin/kexin type 9 (PCSK9) has been regarded as an effective and exciting target in the treatment of atherosclerotic cardiovascular disease since 2003. Only two monoclonal antibodies have been approved in the market which, however, were also criticized for their high cost to $9000 per dose and delivery route. Exploration of natural new effective and cheaper small molecule alternatives with effective PCSK9 inhibition is feasible and desired. PURPOSE: The aim of the study was to explore natural small molecules with anti-hyperlipidemia activity through PCSK9 from Alisma plantago-aquatica. METHOD: A targeted isolation of triterpenoids from A. plantago-aquatica by LC-Orbitrap-QDa was conducted. The isolates were evaluated for their DiI-LDL uptake promoting activity with fluorescence intensity assayed in High-content Imaging System and PCSK9 inhibitory activity by Human PCSK9 Kit or western blot. The LDL uptake and PCSK9 level of target component in different concentrations and their mRNA level were further verified by corresponding kit, qPCR and western blot. RESULTS: Six novel triterpenoids, including three unusual nor-triterpenoids (1-3) and three protostane-type triterpenoids (4-6), along with thirty-four known ones, were isolated from A. plantago-aquatica. Compound 2 had the lowest number of carbon atoms than previous reported nor-PTs in this plant. The 17 triterpenoids showed relatively remarkable activities in promoting LDL uptake with relevant structure-activity relationships. And 6 triterpenoids may improve LDL uptake in HepG2 cells by inhibiting PCSK9, especially for alisol G (28) with PCSK9 inhibition reaching to 55.6%, which demonstrated to increase LDLR mRNA or protein, and simultaneously reduce PCSK9 mRNA or protein significantly. CONCLUSION: The protostane triterpenoids may serve as a new source for PCSK9 inhibitors.

Differential Effect of Dietary Supplementation with a Soybean Oil Enriched in Oleic Acid versus Linoleic Acid on Plasma Lipids and Atherosclerosis in LDLR-Deficient Mice.

Both monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs) play important roles in lipid metabolism, and diets enriched with either of these two fatty acids are associated with decreased cardiovascular risk. Conventional soybean oil (CSO), a common food ingredient, predominantly contains linoleic acid (LA; C18:2), a n-6 PUFA. Recently, a modified soybean oil (MSO) enriched in oleic acid (C18:1), a n-9 MUFA, has been developed, because of its improved chemical stability to oxidation. However, the effect of the different dietary soybean oils on cardiovascular disease remains unknown. To test whether diets rich in CSO versus MSO would attenuate atherosclerosis development, LDL receptor knock-out (LDLR-KO) mice were fed a Western diet enriched in saturated fatty acids (control), or a Western diet supplemented with 5% (w/w) LA-rich CSO or high-oleic MSO for 12 weeks. Both soybean oils contained a similar amount of linolenic acid (C18:3 n-3). The CSO diet decreased plasma lipid levels and the cholesterol content of VLDL and LDL by approximately 18% (p < 0.05), likely from increased hepatic levels of PUFA, which favorably regulated genes involved in cholesterol metabolism. The MSO diet, but not the CSO diet, suppressed atherosclerotic plaque size compared to the Western control diet (Control Western diet: 6.5 ± 0.9%; CSO diet: 6.4 ± 0.7%; MSO diet: 4.0 ± 0.5%) (p < 0.05), independent of plasma lipid level changes. The MSO diet also decreased the ratio of n-6/n-3 PUFA in the liver (Control Western diet: 4.5 ± 0.2; CSO diet: 6.1 ± 0.2; MSO diet: 2.9 ± 0.2) (p < 0.05), which correlated with favorable hepatic gene expression changes in lipid metabolism and markers of systemic inflammation. In conclusion, supplementation of the Western diet with MSO, but not CSO, reduced atherosclerosis development in LDLR-KO mice independent of changes in plasma lipids.

Hempseed (Cannabis sativa) Peptide H3 (IGFLIIWV) Exerts Cholesterol-Lowering Effects in Human Hepatic Cell Line.

Hempseed (Cannabis sativa) protein is an important source of bioactive peptides. H3 (IGFLIIWV), a transepithelial transported intestinal peptide obtained from the hydrolysis of hempseed protein with pepsin, carries out antioxidant and anti-inflammatory activities in HepG2 cells. In this study, the main aim was to assess its hypocholesterolemic effects at a cellular level and the mechanisms behind this health-promoting activity. The results showed that peptide H3 inhibited the 3-hydroxy-3-methylglutaryl co-enzyme A reductase (HMGCoAR) activity in vitro in a dose-dependent manner with an IC50 value of 59 µM. Furthermore, the activation of the sterol regulatory element binding proteins (SREBP)-2 transcription factor, followed by the increase of low-density lipoprotein (LDL) receptor (LDLR) protein levels, was observed in human hepatic HepG2 cells treated with peptide H3 at 25 µM. Meanwhile, peptide H3 regulated the intracellular HMGCoAR activity through the increase of its phosphorylation by the activation of AMP-activated protein kinase (AMPK)-pathways. Consequently, the augmentation of the LDLR localized on the cellular membranes led to the improved ability of HepG2 cells to uptake extracellular LDL with a positive effect on cholesterol levels. Unlike the complete hempseed hydrolysate (HP), peptide H3 can reduce the proprotein convertase subtilisin/kexin 9 (PCSK9) protein levels and its secretion in the extracellular environment via the decrease of hepatic nuclear factor 1-α (HNF1-α). Considering all these evidences, H3 may represent a new bioactive peptide to be used for the development of dietary supplements and/or peptidomimetics for cardiovascular disease (CVD) prevention.

NMR, LC-MS Characterization of Rydingia michauxii Extracts, Identification of Natural Products Acting as Modulators of LDLR and PCSK9.

Rydingia michauxii (Briq.) Scheen and V.A.Albert (Lamiaceae) is used in Iranian traditional medicine to treat malaria, diabetes, hyperlipidemia, rheumatism and cardiovascular diseases. NMR and LC-DAD-MSn analyses were used to establish extract composition and phenylethanoid, flavonoid glycosides, lignans, labdane diterpenes and iridoids were identified and quantified. The main constituents were isolated, and structures were elucidated based on NMR, polarimetric and MS measurements. A new natural compound, ent-labda-8(17),13-dien-18-glucopyranosyl ester-15,16-olide is described here. The effects of ent-labda-8(17),13-dien-18-oic acid-15,16-olide (1), ent-labda-8(17),13-dien-18-glucopyranosyl es-ter-15,16-olide (2), antirrhinoside (3), echinacoside (4), verbascoside (5), and apigenin 6,8-di-C-glucoside (6), on the low-density lipoprotein receptor (LDLR) and proprotein convertase subtilisin/kexin type 9 (PCSK9), were studied in the human hepatocarcinoma cell line Huh7. Among the six constituents, (3) showed the strongest induction of the LDLR (3.7 ± 2.2 fold vs. control) and PCSK9 (3.2 ± 1.5 fold vs. control) at a concentration of 50 µM. The in vitro observations indicated a potential lipid lowering activity of (3) with a statin-like mechanism of action.

The Activity of Ten Natural Extracts Combined in a Unique Blend to Maintain Cholesterol Homeostasis-In Vitro Model.

BACKGROUND: Hypercholesterolemia is a major cause of cardiovascular disease and statins, the HMGCoA inhibitors, are the most prescribed drugs. Statins reduce the production of hepatic cholesterol, leading to greater expression of the LDL receptor and greater absorption of circulating LDL, reducing peripheral LDL levels. Unfortunately, statins are believed to induce myopathy and other severe diseases. To overcome this problem, safe nutraceuticals with the same activity as statins could hold great promise in the prevention and treatment of hypercholesterolemia. In this study, the anti-cholesterol efficacy of a new nutraceutical, called Esterol10®, was evaluated. METHODS: HepG2 cells were used to study the biological mechanisms exerted by Esterol10® analyzing different processes involved in cholesterol metabolism, also comparing data with Atorvastatin. RESULTS: Our results indicate that Esterol10® leads to a reduction in total hepatocyte cholesterol and an improvement in the biosynthesis of free cholesterol and bile acids. Furthermore, the anti-cholesterol activity of Esterol10® was also confirmed by the modulation of the LDL receptor and by the accumulation of lipids, as well as by the main intracellular pathways involved in the metabolism of cholesterol. CONCLUSIONS: Esterol10® is safe and effective with anti-cholesterol activity, potentially providing an alternative therapy to those based on statins for hypercholesterolemia disease.

Sexual dimorphism: increased sterol excretion leads to hypocholesterolaemia in female hyperbilirubinaemic Gunn rats.

Circulating bilirubin is associated with reduced serum cholesterol concentrations in humans and in hyperbilirubinaemic Gunn rats. However, mechanisms contributing to hypocholesterolaemia remain unknown. Therefore, this study aimed to investigate cholesterol synthesis, transport and excretion in mutant Gunn rats. Adult Gunn and control rats were assessed for daily faecal sterol excretion using metabolic cages, and water was supplemented with [1-13 C]-acetate to determine cholesterol synthesis. Bile was collected to measure biliary lipid secretion. Serum and liver were collected for biochemical analysis and for gene/protein expression using RT-qPCR and western blot, respectively. Additionally, serum was collected and analysed from juvenile rats. A significant interaction of sex, age and phenotype on circulating lipids was found with adult female Gunn rats reporting significantly lower cholesterol and phospholipids. Female Gunn rats also demonstrated elevated cholesterol synthesis, greater biliary lipid secretion and increased total faecal cholesterol and bile acid excretion. Furthermore, they possessed increased hepatic low-density lipoprotein (LDL) receptor and SREBP2 expression. In contrast, there were no changes to sterol metabolism in adult male Gunn rats. This is the first study to demonstrate elevated faecal sterol excretion in female hyperbilirubinaemic Gunn rats. Increased sterol excretion creates a negative intestinal sterol balance that is compensated for by increased cholesterol synthesis and LDL receptor expression. Therefore, reduced circulating cholesterol is potentially caused by increased hepatic uptake via the LDL receptor. Future studies are required to further evaluate the sexual dimorphism of this response and whether similar findings occur in females with benign unconjugated hyperbilirubinaemia (Gilbert's syndrome). KEY POINTS: Female adult hyperbilirubinaemic (Gunn) rats demonstrated lower circulating cholesterol, corroborating human studies that report a negative association between bilirubin and cholesterol concentrations. Furthermore, female Gunn rats had elevated sterol excretion creating a negative intestinal sterol balance that was compensated for by elevated cholesterol synthesis and increased hepatic low-density lipoprotein (LDL) receptor expression. Therefore, elevated LDL receptor expression potentially leads to reduced circulating cholesterol levels in female Gunn rats providing an explanation for the hypocholesterolaemia observed in humans with elevated bilirubin levels. This study also reports a novel interaction of sex with the hyperbilirubinaemic phenotype on sterol metabolism because changes were only reported in females and not in male Gunn rats. Future studies are required to further evaluate the sexual dimorphism of this response and whether similar findings occur in females with benign unconjugated hyperbilirubinaemia (Gilbert's syndrome).

[Molecular mechanism of astragaloside â £ against atherosclerosis by regulating miR-17-5p and PCSK9/VLDLR signal pathway].

This study explores the regulatory effect of astragaloside Ⅳ on miR-17-5 p and its downstream proprotein convertase subtillisin/kexin type 9(PCSK9)/very low density lipoprotein receptor(VLDLR) signal pathway, aiming at elucidating the mechanism of astragaloside Ⅳ against atherosclerosis(AS). In cell experiment, oxidized low-density lipoprotein(ox-LDL) was used for endothelial cell injury modeling with vascular smooth muscle cells(VSMCs). Then cells were classified into the model group, miR-17-5 p inhibitor group, blank serum group, and astragaloside Ⅳ-containing serum group based on the invention. Afterward, cell viability and the expression of miR-17-5 p, VLDLR, and PCSK9 mRNA and protein in cells in each group were detected. In animal experiment, 15 C57 BL/6 mice were used as the control group, and 45 ApoE~(-/-) mice were classified into the model group, miR-17-5 p inhibitor group, and astragaloside Ⅳ group, with 15 mice in each group. After 8 weeks of intervention, the peripheral serum levels of interleukin-6(IL-6), interleukin-10(IL-10), and tumor necrosis factor-α(TNF-α), and the expression of miR-17-5 p, VLDLR, and PCSK9 mRNA in the aorta of mice were detected. The pathological changes of mice in each group were observed. According to the cell experiment, VSMC viability in the miR-17-5 p inhibitor group and the astragaloside Ⅳ-containing serum group was higher than that in the model group(P<0.05). The mRNA and protein expression of miR-17-5 p and VLDLR in VSMCs in the miR-17-5 p inhibitor group and the astragaloside Ⅳ-containing serum group was lower than that in the model group(P<0.05), but the mRNA and protein expression of PCSK9 was higher than that in the model group(P<0.05). As for the animal experiment, the levels of IL-6 and TNF-α in the peripheral serum of the miR-17-5 p inhibitor group and the astragaloside Ⅳ group were lower(P<0.05) and the serum level of IL-10 was higher(P<0.05) than that of the model group. The mRNA expression of miR-17-5 p and VLDLR in the aorta in the miR-17-5 p inhibitor group and the astragaloside Ⅳ group was lower(P<0.05), and PCSK9 mRNA expression was higher(P<0.05) than that in the model group. Pathological observation showed mild AS in the miR-17-5 p inhibitor group and the astragaloside Ⅳ group. In summary, astragaloside Ⅳ can prevent the occurrence and development of AS. The mechanism is that it performs targeted regulation of miR-17-5 p, further affecting the PCSK9/VLDLR signal pathway, inhibiting vascular inflammation, and thus alleviating endothelial cell injury.

A triple combination strategy of UHPLC-MSn, hypolipidemic activity and transcriptome sequencing to unveil the hypolipidemic mechanism of Nelumbo nucifera alkaloids.

ETHNOPHARMACOLOGICAL RELEVANCE: Nelumbo nucifera (N. nucifera), a kind of edible Chinese herbal, has been studied in treating hyperlipidemia. However, the hypolipidemic mechanism of N. nucifera remains unknown. Aims of this review: We aimed to screen the effective constituent of N. nucifera alkaloids and elucidated the potential mechanism for treating hyperlipidemia. A triple combination strategy of UHPLC-MSn, hypolipidemic activity and transcriptome sequencing was built to unveil the hypolipidemic mechanism of Nelumbo nucifera alkaloid. MATERIALS AND METHODS: We comprehensively investigated the characterization of N. nucifera alkaloids by using UHPLC-LTQ-Orbitrap MSn. And the hypolipidemic activity of candidate active ingredients were evaluated on sodium oleate-induced HepG2 cell. Finally, O-nornuciferine and N. nucifera alkaloid extraction were analyzed by RNA sequence (RNA-seq) to decipher the underlying hypolipidemic mechanism and were verified by qRT-PCR. RESULTS: 35 compounds were identified from N. nucifera alkaloid extraction by UHPLC-LTQ-Orbitrap MSn. Among them, O-nornuciferine and N. nucifera alkaloid extraction which showed significant hypolipidemic activity were analyzed by transcriptome sequencing. After the intervention of O-nornuciferine and N. nucifera alkaloid extraction, 1 and 158 differentially expressed genes (DEGs) were identified, severally. The enrichment analysis indicated that the hypolipidemic effect was adjusted by the expression of numerous key DEGs involved in bile secretion, glycerolipid and sphingolipid metabolism, PPAR signaling pathway. CONCLUSIONS: O-nornuciferine and N. nucifera alkaloids had exibited significant effects in hyperlipidemia. The candidate genes were LDLR, LPL and ANGPTL4, etc. It was most likely that they adjusted lipid metabolism by modulating expression levels of various key factors which were involved in bile secretion, glycerolipid metabolism, sphingolipid metabolism and PPAR signaling pathway, and so on. This study clarified the hypolipidemic mechanism of the alkaloids in N. nucifera, and laid a foundation for the subsequent development of clinical application and better quality of N. nucifera.

Dietary Neu5Ac Intervention Protects Against Atherosclerosis Associated With Human-Like Neu5Gc Loss-Brief Report.

Objective: Species-specific pseudogenization of the CMAH gene during human evolution eliminated common mammalian sialic acid N-glycolylneuraminic acid (Neu5Gc) biosynthesis from its precursor N-acetylneuraminic acid (Neu5Ac). With metabolic nonhuman Neu5Gc incorporation into endothelia from red meat, the major dietary source, anti-Neu5Gc antibodies appeared. Human-like Ldlr-/-Cmah-/- mice on a high-fat diet supplemented with a Neu5Gc-enriched mucin, to mimic human red meat consumption, suffered increased atherosclerosis if human-like anti-Neu5Gc antibodies were elicited. Approach and Results: We now ask whether interventional Neu5Ac feeding attenuates metabolically incorporated Neu5Gc-mediated inflammatory acceleration of atherogenesis in this Cmah-/-Ldlr-/- model system. Switching to a Neu5Gc-free high-fat diet or adding a 5-fold excess of Collocalia mucoid-derived Neu5Ac in high-fat diet protects against accelerated atherosclerosis. Switching completely from a Neu5Gc-rich to a Neu5Ac-rich diet further reduces severity. Remarkably, feeding Neu5Ac-enriched high-fat diet alone has a substantial intrinsic protective effect against atherosclerosis in Ldlr-/- mice even in the absence of dietary Neu5Gc but only in the human-like Cmah-null background. Conclusions: Interventional Neu5Ac feeding can mitigate or prevent the red meat/Neu5Gc-mediated increased risk for atherosclerosis, and has an intrinsic protective effect, even in the absence of Neu5Gc feeding. These findings suggest that similar interventions should be tried in humans and that Neu5Ac-enriched diets alone should also be investigated further.

High fat / high cholesterol diet does not provoke atherosclerosis in the ω3-and ω6-polyunsaturated fatty acid synthesis-inactivated Δ6-fatty acid desaturase-deficient mouse.

OBJECTIVE: An increased ω6/ω3-polyunsaturated fatty acid ratio in the current Western diet is regarded as a critical epigenetic nutritional factor in the pathogenesis of several human lifestyle diseases, metabolic syndrome, cardiovascular disease, the central nervous system and the female and male reproductive systems. The impact of nutrient ω3-and ω6-PUFAs in the pathogenesis of dyslipoproteinemia and atherosclerosis has been a topic of intense efforts for several decades. Cellular homeostasis of the ω3-and ω6- PUFA pool is maintained by the synthesis of ω3-and ω6-PUFAs from essential fatty acids (EFA) (linoleic and α-linolenic acid) and their dietary supply. In this study, we used the auxotrophic Δ6-fatty acid desaturase- (FADS2) deficient mouse (fads2-/-), an unbiased model congenial for stringent feeding experiments, to investigate the molecular basis of the proposed protective role of dietary ω3-and ω6-PUFAs (Western diet) in the pathogenesis of multifactorial dyslipoproteinemia and atherosclerosis. We focused on the metabolic axis-liver endoplasmic reticulum (ER), serum lipoprotein system (Lp) and aorta vessel wall. Furthermore, we addressed the impact of the inactivated fads2-locus with inactivated PUFA synthesis on the development and progression of extended atherosclerosis in two different mouse mutants with disrupted cholesterol homeostasis, using the apoe-/- and ldlr-/- mutants and the fads2-/- x apoe-/- and fads2-/- x ldlr-/- double mutants. METHODS: Cohorts of +/+ and fads2-/- mice underwent two long-term dietary regimens: a) a PUFA-free standard chow diet containing only EFAs, essential for viability, and b) a high fat/high cholesterol (HFHC) diet, a mimicry of the human atherogenic "Western" diet. c) To study the molecular impact of PUFA synthesis deficiency on the development and progression of atherosclerosis in the hypercholesterolemic apoe-/- and ldlr-/- mouse models fed PUFA-free regular and sustained HFHC diets, we generated the fads2-/- x apoe-/- and the fads2-/- x ldlr-/- double knockout mutants. We assessed essential molecular, biochemical and cell biological links between the diet-induced modified lipidomes of the membrane systems of the endoplasmic reticulum/Golgi complex, the site of lipid synthesis, the PL monolayer and neutral lipid core of LD and serum-Lp profiles and cellular reactions in the aortic wall. RESULTS: ω3-and ω6-PUFA synthesis deficiency in the fads2-/- mouse causes a) hypocholesterolemia and hypotriglyceridemia, b) dyslipoproteinemia with a shift of high-density lipoprotein (HDL) to very low-density lipoprotein (VLDL)-enriched Lp-pattern and c) altered liver lipid droplet structures. d) Long-term HFHC diet does not trigger atherosclerotic plaque formation in the aortic arc, the thoracic and abdominal aorta of PUFA-deficient fads2-/- mice. Inactivation of the fads2-/- locus, abolishing systemic PUFA synthesis in the fads2-/- x apoe-/- and fads2-/- x ldlr-/- double knockout mouse lines. CONCLUSIONS: Deficiency of ω3-and ω6-PUFA in the fads2-/- mutant perturbs liver lipid metabolism, causes hypocholesterolemia and hypotriglyceridemia and renders the fads2-/- mutant resistant to sustained atherogenic HFHC diet. Neither PUFA-free regular nor long-term HFHC-diet impacts the apoe- and LDL-receptor deficiency-provoked hypercholesterolemia and atherosclerotic plaque formation, size and distribution in the aorta. Our study strongly suggests that the absence of PUFAs as highly vulnerable chemical targets of autoxidation attenuates inflammatory responses and the formation of atherosclerotic lesions. The cumulative data and insight into the molecular basis of the pleiotropic functions of PUFAs challenge a differentiated view of PUFAs as culprits or benefactors during a lifespan, pivotal for legitimate dietary recommendations.

Gypenoside LVI improves hepatic LDL uptake by decreasing PCSK9 and upregulating LDLR expression.

BACKGROUNDS: Atherosclerotic Cardiovascular Disease (ASCVD) is defined as ischemic or endothelial dysfunction-various inflammatory diseases, which is mainly caused by excessive low-density lipoprotein cholesterol (LDL-C) in circulating blood. Gynostemma pentaphyllum is a traditional Chinese medicine, and total Gypenosides are used for the treatment of hyperlipidemia and to reduce circulating proprotein convertase subtilisin/kexin type 9 (PCSK9) level. However, which gypenoside involved in the modulation of PCSK9 expression is still unknown. PURPOSE: This study aimed to discover effective PCSK9 inhibitors from Gypenosides in accordance with the 2019 ESC/EAS guidelines. METHODS: HPLC was employed to determine major six components of Gypenosides. The inhibitory activity on secreted PCSK9 in HepG2 of six major compounds from Gypenosides were screened by ELISA. The level of low-density lipoprotein (LDL) receptor (LDLR) was determined by Flow cytometry and Immunofluorescence. The expression levels of PCSK9, LDLR and Sterol-regulatory element binding proteins-2 (SREBP-2) were analyzed by qPCR and Western blot. DiI-LDL was added to evaluated LDL uptake into HepG2. RESULTS: The results suggested that the mRNA and protein levels of PCSK9 were down-regulated by Gypenoside LVI and the LDLR degradation in lysosomes system was inhibited, thereby leading to an increasing in LDL uptake into HepG2 cells. Furthermore, Gypenoside LVI decreased PCSK9 expression induced by stains. Altogether, Gypenoside LVI enhances LDL uptake into HepG2 cells by increased LDLR level on cell-surface and suppressed PCSK9 expression. CONCLUSION: This indicates that Gypenoside LVI can be used as a useful supplement for statins in the treatment of hypercholesterolemia. This is firstly reported that monomeric compound of G. pentaphyllum planted in Hunan province has the effect of increasing LDL-C uptake in hepatocytes via inhibiting PCSK9 expression.

The Modulation of PCSK9 and LDLR by Supercritical CO2 Extracts of Mentha longifolia and Isolated Piperitone Oxide, an In Vitro Study.

In the present study the ability of supercritical carbon dioxide (SCO2) extracts of M. longifolia L. leaves to modulate low-density lipoprotein receptor (LDLR) and proprotein convertase subtilisin/kexin type 9 (PCSK9) expression was evaluated in cultured human hepatoma cell lines Huh7 and HepG2. Two SCO2 extracts, one oil (ML-SCO2) and a semisolid (MW-SCO2), were subjected to detailed chemical characterization by mono- and bidimensional nuclear magnetic resonance (1D, 2D-NMR), gas chromatography coupled with mass spectrometry (GC-MS) and liquid chromatography coupled with mass spectrometry (LC-MS). Chemical analysis revealed significant amounts of fatty acids, phytosterols and terpenoids. ML-SCO2 was able to induce LDLR expression at a dose of 60 µg/mL in HuH7 and HepG2 cell lines. Furthermore, ML-SCO2 reduced PCSK9 secretion in a concentration-dependent manner in both cell lines. Piperitone oxide, the most abundant compound of the volatile constituent of ML-SCO2 (27% w/w), was isolated and tested for the same targets, showing a very effective reduction of PCSK9 expression. The overall results revealed the opportunity to obtain a new nutraceutical ingredient with a high amount of phytosterols and terpenoids using the SCO2 extraction of M. longifolia L., a very well-known botanical species used as food. Furthermore, for the first time we report the high activity of piperitone oxide in the reduction of PCSK9 expression.

Low Dose of Emodin Inhibits Hypercholesterolemia in a Rat Model of High Cholesterol.

BACKGROUND Emodin has been widely used in traditional Chinese medicine, but few studies have tried to understand the mechanism of its anti-hypercholesterolemic effect. MATERIAL AND METHODS To delineate the underlying pathways, high-cholesterol diet (HCD)-fed Sprague-Dawley rats were orally administrated emodin or the lipid-lowering medicine simvastatin. Emodin was administered at 10, 30, or 100 mg/kg, while simvastatin was administered at 10 mg/kg. Parameters measured included lipid profiles (serum total cholesterol, triglycerides, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol, aorta endothelium-dependent vasorelaxation in response to acetylcholine, and nitric oxide (NO) production. RT-qPCR and western blotting were performed to evaluate aortic endothelial nitric oxide synthase (eNOS), phosphorylated eNOS (p-eNOS), and hepatic LDL receptor (LDLR). Indices of liver and serum oxidation were also measured. RESULTS The atherogenic index was increased by the HCD but significantly reduced in all treatment groups. The HCD-fed experimental group treated with emodin at 10 mg/kg had significantly lower serum total-C and LDL-C and improved aorta vasorelaxation and enhanced NO production. Also, emodin significantly attenuated the lipid profiles and restored endothelial function, as reflected by upregulated expression of hepatic LDLR and p-eNOS, respectively. Furthermore, emodin at 10 mg/kg significantly enhanced superoxide dismutase activity, lowered the malondialdehyde level in both liver and serum, and enhanced catalase activity in serum. CONCLUSIONS The ability of emodin to inhibit hypercholesterolemia in HCD-fed rats was associated with lower serum total-C and LDL-C, restoration of aortic endothelial function, and improved antioxidant capacity. Low-dose emodin showed better protection of aortic endothelium and better antioxidant activity than did higher doses.