Elder (Sambucus nigra), identified by high-content screening, counteracts foam cell formation without promoting hepatic lipogenesis.

Cholesterol deposition in intimal macrophages leads to foam cell formation and atherosclerosis. Reverse cholesterol transport (RCT), initiated by efflux of excess cholesterol from foam cells, counteracts atherosclerosis. However, targeting RCT by enhancing cholesterol efflux was so far accompanied by adverse hepatic lipogenesis. Here, we aimed to identify novel natural enhancers of macrophage cholesterol efflux suitable for the prevention of atherosclerosis. Plant extracts of an open-access library were screened for their capacity to increase cholesterol efflux in RAW264.7 macrophages trace-labeled with fluorescent BODIPY-cholesterol. Incremental functional validation of hits yielded two final extracts, elder (Sambucus nigra) and bitter orange (Citrus aurantium L.) that induced ATP binding cassette transporter A1 (ABCA1) expression and reduced cholesteryl ester accumulation in aggregated LDL-induced foam cells. Aqueous elder extracts were subsequently prepared in-house and both, flower and leaf extracts increased ABCA1 mRNA and protein expression in human THP-1 macrophages, while lipogenic gene expression in hepatocyte-derived cells was not induced. Chlorogenic acid isomers and the quercetin glycoside rutin were identified as the main polyphenols in elder extracts with putative biological action. In summary, elder flower and leaf extracts increase macrophage ABCA1 expression and reduce foam cell formation without adversely affecting hepatic lipogenesis.

QiShenYiQi pill inhibits atherosclerosis by promoting reverse cholesterol transport PPARγ-LXRα/ß-ABCA1 pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: QiShenYiQi pill (QSYQ), a Chinese compound medicine, originate from BuYangHuanWu decoction in the Qing dynasty, and has been used to treat ischemic cardiovascular diseases for more than two hundred years in China. Multi-central randomized double-blind controlled studies have proved that QSYQ has similar efficacy as enteric coated aspirin in the secondary prevention of myocardial infarction. AIM OF STUDY: The aim of study was to explore the effect of QSYQ on reverse cholesterol transport (RCT) pathway during atherosclerosis. MATERIALS AND METHODS: Eight-week-old male apoE-/- mice (on the gene background of C57BL/6J) were fed with a high-fat western diet and treated with low dose and high dose of QSYQ, as well as the positive control agent, liver X receptor-α (LXR-α) agonist GW3965. Eight weeks later, mice were sacrificed and the aorta was collected for atherosclerotic analysis. The aortic root was stained with Oil red O to evaluate the area of atherosclerotic lesion, and stained with immunohistochemistry to analyze the intra-plaque component and RCT protein in atherosclerotic plaque. The thoracic aorta was used to detect differentially expressed genes by comparative transcriptome RNA-seq and the protein expression of RCT pathway by western blotting. RESULTS: After eight weeks of treatment, we found that both of QSYQ and LXR-α agonist reduced atherosclerotic plaque area significantly, and decreased the intra-plaque component, including the lipid, the smooth muscle cell and the macrophage. Compared with the control group, there were 49 differentially expressed genes in low-dose QSYQ group, including 21 up-regulated genes and 28 down-regulated genes. The results of GO and KEGG analysis showed that the differentially expressed genes mainly concentrated in the negative regulation of lipid biosynthesis, positive regulation of lipid metabolism, cell response to lipids, negative regulation of lipid storage, fatty acid degradation, and glycerol ester metabolism. Both of QSYQ and LXR-α agonist reduced the protein expression of CD36 and increased the protein expression of PPARγ-LXRα/ß-ABCA1 in atherosclerotic plaque. CONCLUSION: The anti-atherosclerotic mechanism of QSYQ was involved in inhibiting lipid phagocytosis and promoting reverse cholesterol transport, therefore reducing lipid deposition and inflammatory cells in plaque.

Photobiomodulation therapy promotes the ATP-binding cassette transporter A1-dependent cholesterol efflux in macrophage to ameliorate atherosclerosis.

Atherosclerosis is a chronic inflammatory disease related to a massive accumulation of cholesterol in the artery wall. Photobiomodulation therapy (PBMT) has been reported to possess cardioprotective effects but has no consensus on the underlying mechanisms. Here, we aimed to investigate whether PBMT could ameliorate atherosclerosis and explore the potential molecular mechanisms. The Apolipoprotein E (ApoE)-/- mice were fed with western diet (WD) for 18 weeks and treated with PBMT once a day in the last 10 weeks. Quantification based on Oil red O-stained aortas showed that the average plaque area decreased 8.306 ± 2.012% after PBMT (P < .05). Meanwhile, we observed that high-density lipoprotein cholesterol level in WD + PBMT mice increased from 0.309 ± 0.037 to 0.472 ± 0.038 nmol/L (P < .05) compared with WD mice. The further results suggested that PBMT could promote cholesterol efflux from lipid-loaded primary peritoneal macrophages and inhibit foam cells formation via up-regulating the ATP-binding cassette transporters A1 expression. A contributing mechanism involved in activating the phosphatidylinositol 3-kinases/protein kinase C zeta/specificity protein 1 signalling cascade. Our study outlines that PBMT has a protective role on atherosclerosis by promoting macrophages cholesterol efflux and provides a new strategy for treating atherosclerosis.

Myristica fragrans promotes ABCA1 expression and cholesterol efflux in THP-1-derived macrophages.

Myristica fragrans is a traditional herbal medicine and has been shown to alleviate the development of atherosclerosis. However, the anti-atherogenic mechanisms of M. fragrans are still to be addressed. In this study, we explored the effect of M. fragrans on lipid metabolism and inflammation and its mechanisms in THP-1-derived macrophages. The quantitative polymerase chain reaction and western blot analysis results showed that M. fragrans promotes cholesterol efflux from THP-1-derived macrophages and reduces intracellular total cholesterol, cholesterol ester, and free cholesterol contents in a dose- and a time-dependent manner. Further study found that liver X receptor alpha (LXRα) antagonist GGPP significantly blocked the upregulation of ABCA1 expression with M. fragrans treatment. In addition, chromatin immunoprecipitation assay confirmed that GATA binding protein 3 (GATA3) can bind to the LXRα promoter, and inhibition of GATA3 led to the downregulation of LXRα and ATP-binding cassette subfamily A member 1 expression. Furthermore, M. fragrans reduced lipid accumulation, followed by decreasing tumor necrosis factor-α, interleukin (IL)-6, and IL-1ß and increasing IL-10 produced by THP-1-derived macrophages. Therefore, M. fragrans is identified as a valuable therapeutic medicine for atherosclerotic cardiovascular disease.

Celastrol induces lipophagy via the LXRα/ABCA1 pathway in clear cell renal cell carcinoma.

Celastrol is a triterpene derived from the traditional Chinese medicine Tripterygium wilfordii Hook f, which displays potential anticancer activity. In the present study, we investigated the anticancer effects of celastrol against clear cell renal cell carcinoma (ccRCC) and the underlying mechanisms. Using Cancer Genome Atlas (TCGA) database and genotype-tissue expression (GTEx) database we conducted a bioinformatics analysis, which showed that the mRNA levels of liver-X receptors α (LXRα) and ATP-binding cassette transporter A1 (ABCA1) in ccRCC tissues were significantly lower than those in adjacent normal tissues. This result was confirmed by immunoblotting analysis of 4 ccRCC clinical specimens, which showed that the protein expression of LXRα and ABCA1 was downregulated. Similar results were obtained in a panel of ccRCC cell lines (786-O, A498, SN12C, and OS-RC-2). In 786-O and SN12C cells, treatment with celastrol (0.25-2.0 µM) concentration-dependently inhibited the cell proliferation, migration, and invasion as well as the epithelial-mesenchymal transition (EMT) process. Furthermore, we demonstrated that celastrol inhibited the invasion of 786-O cells through reducing lipid accumulation; celastrol concentration-dependently promoted autophagy to reduce lipid storage. Moreover, we revealed that celastrol dramatically activated LXRα signaling, and degraded lipid droplets by inducing lipophagy in 786-O cells. Finally, celastrol promoted cholesterol efflux from 786-O cells via ABCA1. In high-fat diet-promoted ccRCC cell line 786-O xenograft model, administration of celastrol (0.25, 0.5, 1.0 mg·kg-1·d-1, for 4 weeks, i.p.) dose-dependently inhibited the tumor growth with upregulated LXRα and ABCA1 protein in tumor tissue. In conclusion, this study reveals that celastrol triggers lipophagy in ccRCC by activating LXRα, promotes ABCA1-mediated cholesterol efflux, suppresses EMT progress, and ultimately inhibits cell proliferation, migration, and invasion as well as tumor growth. Thus, our study provides evidence that celastrol can be used as a lipid metabolism-based anticancer therapeutic approach.

Mechanistic convergence and shared therapeutic targets in Niemann-Pick disease.

Niemann-Pick disease type C (NPC) and Tangier disease are genetically and clinically distinct rare inborn errors of metabolism. NPC is caused by defects in either NPC1 or NPC2; whereas Tangier disease is caused by a defect in ABCA1. Tangier disease is currently without therapy, whereas NPC can be treated with miglustat, a small molecule inhibitor of glycosphingolipid biosynthesis that slows the neurological course of the disease. When a Tangier disease patient was misdiagnosed with NPC and treated with miglustat, her symptoms improved. This prompted us to consider whether there is mechanistic convergence between these two apparently unrelated rare inherited metabolic diseases. In this study, we found that when ABCA1 is defective (Tangier disease) there is secondary inhibition of the NPC disease pathway, linking these two diseases at the level of cellular pathophysiology. In addition, this study further supports the hypothesis that miglustat, as well as other substrate reduction therapies, may be potential therapeutic agents for treating Tangier disease as fibroblasts from multiple Tangier patients were corrected by miglustat treatment.

Cholesterol depletion sensitizes gallbladder cancer to cisplatin by impairing DNA damage response.

Gallbladder cancer (GBC) is the common malignancy of the bile tract system with extremely poor clinical outcomes, owing to its metastatic property and intrinsic resistance to the first-line drugs. Although it is well-established that cholesterol abnormity contributes to gallstone formation, a leading risk factor for GBC, the link of cholesterol homeostasis with GBC has not been investigated. The present study systematically examined the genes implicated in cholesterol homeostasis, and revealed altered gene expressions of de novo cholesterol biosynthesis and sterol sulfonation (SULT2B1), reduced bile acid synthesis (CYP7B1 and CYP39A1) and impaired sterol efflux (ABCA1, ABCG5, LCAT, and CETP) in GBC tissues. Suppression of cholesterol biosynthesis by lovastatin inhibited GBC cell proliferation possibly through attenuating the DNA repair process. Further investigation revealed lovastatin sensitized GBC cells to cisplatin-induced apoptosis and suppressed the activation of CHK1, CHK2, and H2AX during DNA damage response. By using chemically distinct statins, HMGCR depletion or supplementing mevalonate, the product of HMGCR, we showed the inhibitory effects on DNA repair process of lovastatin were due to the blockage of the mevalonate pathway. Subcutaneous xenograft mice model suggested lovastatin promoted the therapeutic efficacy of cisplatin, and significantly prolonged the survival times of tumor-bearing mice. Moreover, HMGCR ablation repressed tumor growth in vivo, which can be rescued partially by restored expression of HMGCR, suggesting the on-target effects of lovastatin. Therefore, our study provides the clinical relevance of cholesterol homeostasis with GBC progression, and highlights a novel intervention of combined use of lovastatin and cisplatin for GBC.

Moxibustion at CV4 alleviates atherosclerotic lesions through activation of the LXRα/ABCA1 pathway in apolipoprotein-E-deficient mice.

OBJECTIVES: To investigate the anti-atherogenic effect of moxibustion and whether it is mediated through the reverse cholesterol transport process. METHODS: 8-week-old male apolipoprotein E deficient (ApoE-/- knockout) mice were randomly divided into two groups (n=10 per group): atherosclerosis (AS) and AS plus moxibustion (AS+M). C57BL/6J mice of the same background (n=10) were selected as controls. Mice in the AS+M group received indirect moxibustion with an ignited moxa stick held over CV4. Mice of the AS and control groups were restrained in the same holder with an unlit moxa stick held over CV4. All treatments were performed for 20 min per day, 6 days per week for 12 weeks. After the treatment, the mice were euthanased and their serum lipids were measured. The aortic roots and thoracic aortas were collected for haematoxylin and eosin and red oil O staining, respectively, to analyse the atherosclerotic lesions. Expression of adenosine triphosphate binding cassette (ABCA)A1/G1 and liver X receptor α (LXRα) in the thoracic aorta were examined with Western blotting. RESULTS: The moxibustion-treated (AS+M) mice showed a significantly lower plaque area percentage in the aortic root and thoracic aorta, and higher expression of LXRα and ABCA1 in the thoracic aorta compared with the AS mice. No significant differences were found in average lipid area percentage in the thoracic aorta, or ABCG1 expression in the thoracic aorta, between mice in the AS+M and AS groups. CONCLUSION: Moxibustion treatment at CV4 suppressed the progression of atherosclerotic lesions in ApoE-/- mice. The anti-atherogenic effect of moxibustion may be achieved by: (1) regulation of lipid metabolism, and thus prevention of lipid accumulation; and (2) upregulation of LXRα- and ABCA1-mediated cholesterol efflux in the lesion area.

Efficacy of Shoushen granule on adenosine triphosphate binding cassette transporter A1, proprotein convertase subtilisin/kexin type 9 and toll-like receptor 4/nuclear factor kappa-B signaling pathway in ApoE-knockout mice.

OBJECTIVE: To evaluate the efficacy of Shoushen granule, prepared with four Chinese medicinals, on the targeted regulation of adenosine triphosphate binding cassette transporter A1 (ABCA1) through proprotein convertase subtilisin/kexin type 9 (PCSK9) and toll-like receptor 4 (TLR4) / nuclear factor kappa-B (NF-κB) signaling pathway to affect atherosclerosis (AS) in ApoE-knockout (ApoE-/-) mice. METHODS: ApoE-/- mice fed with a high-fat diet were used for AS modeling and divided into Model, Shoushen, and Atorvastatin groups. C57BL/6J mice at the same age and background strain were included in the Control group. Western blot and immunohistochemistry were used to measure ABCA1, PCSK9, TLR4, and NF-κB protein expression in mouse aortas. Enzyme-linked immuno sorbent assay was used to measure mouse serum tumor necrosis factor-α (TNF-α), interleukin-10 (IL-10), monocyte chemoattractant protein 1 (MCP-1), and intercellular cell adhesion molecule-1 (ICAM-1) expression. Serum lipid profiles and histopathology were also assessed. Shoushen granule were composed of Heshouwu (Radix Polygoni Multiflori) 15 g, Gouqizi (Fructus Lycii) 15 g, Sheng shanzha (Raw Fructus Crataegus Pinnatifidae) 10 g, and Sanqi (Radix Notoginseng) 3 g. RESULTS: ApoE-/- mice fed with a high-fat diet had notable AS lesions, with reduced ABCA1 and IL-10 levels, elevated PCSK9, TLR4, NF-κB, TNF-α, MCP-1, and ICAM-1 expression, and increased total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C) contents. With drug interventions, the areas of AS plaques were significantly reduced, the ABCA1 and IL-10 levels were increase, while the PCSK9, TLR4, NF-κB, TC, and LDL-C contents, and the TNF-α, MCP-1, and ICAM-1 expression were reduced. CONCLUSION: Shoushen granule effectively interfered with AS development by antagonizing the expression of key factors of the PCSK9 and TLR4/NF-κB signaling pathway to upregulate ABCA1 expression.

Novel interactomics approach identifies ABCA1 as direct target of evodiamine, which increases macrophage cholesterol efflux.

Evodiamine, a bioactive alkaloid from the fruits of the traditional Chinese medicine Evodia rutaecarpa (Juss.) Benth. (Fructus Evodiae, Wuzhuyu), recently gained attention as a dietary supplement for weight loss and optimization of lipid metabolism. In light of its use by patients and consumers, there is an urgent need to elucidate the molecular targets affected by this natural product. Using a novel interactomics approach, the Nematic Protein Organisation Technique (NPOT), we report the identification of ATP-binding cassette transporter A1 (ABCA1), a key membrane transporter contributing to cholesterol efflux (ChE), as a direct binding target of evodiamine. The binding of evodiamine to ABCA1 is confirmed by surface plasmon resonance (SPR) experiments. Examining the functional consequences of ABCA1 binding reveals that evodiamine treatment results in increased ABCA1 stability, elevated cellular ABCA1 protein levels, and ultimately increased ChE from THP-1-derived human macrophages. The protein levels of other relevant cholesterol transporters, ABCG1 and SR-B1, remain unaffected in the presence of evodiamine, and the ABCA1 mRNA level is also not altered.

Complex polymorphisms in endocytosis genes suggest alpha-cyclodextrin as a treatment for breast cancer.

Most breast cancer deaths are caused by metastasis and treatment options beyond radiation and cytotoxic drugs, which have severe side effects, and hormonal treatments, which are or become ineffective for many patients, are urgently needed. This study reanalyzed existing data from three genome-wide association studies (GWAS) using a novel computational biostatistics approach (muGWAS), which had been validated in studies of 600-2000 subjects in epilepsy and autism. MuGWAS jointly analyzes several neighboring single nucleotide polymorphisms while incorporating knowledge about genetics of heritable diseases into the statistical method and about GWAS into the rules for determining adaptive genome-wide significance. Results from three independent GWAS of 1000-2000 subjects each, which were made available under the National Institute of Health's "Up For A Challenge" (U4C) project, not only confirmed cell-cycle control and receptor/AKT signaling, but, for the first time in breast cancer GWAS, also consistently identified many genes involved in endo-/exocytosis (EEC), most of which had already been observed in functional and expression studies of breast cancer. In particular, the findings include genes that translocate (ATP8A1, ATP8B1, ANO4, ABCA1) and metabolize (AGPAT3, AGPAT4, DGKQ, LPPR1) phospholipids entering the phosphatidylinositol cycle, which controls EEC. These novel findings suggest scavenging phospholipids as a novel intervention to control local spread of cancer, packaging of exosomes (which prepare distant microenvironment for organ-specific metastases), and endocytosis of ß1 integrins (which are required for spread of metastatic phenotype and mesenchymal migration of tumor cells). Beta-cyclodextrins (ßCD) have already been shown to be effective in in vitro and animal studies of breast cancer, but exhibits cholesterol-related ototoxicity. The smaller alpha-cyclodextrins (αCD) also scavenges phospholipids, but cannot fit cholesterol. An in-vitro study presented here confirms hydroxypropyl (HP)-αCD to be twice as effective as HPßCD against migration of human cells of both receptor negative and estrogen-receptor positive breast cancer. If the previous successful animal studies with ßCDs are replicated with the safer and more effective αCDs, clinical trials of adjuvant treatment with αCDs are warranted. Ultimately, all breast cancer are expected to benefit from treatment with HPαCD, but women with triple-negative breast cancer (TNBC) will benefit most, because they have fewer treatment options and their cancer advances more aggressively.

Inhibition of protein arginine methyltransferase 3 activity selectively impairs liver X receptor-driven transcription of hepatic lipogenic genes in vivo.

BACKGROUND AND PURPOSE: Agonists for the liver X receptor (LXR) are considered promising therapeutic moieties in cholesterol-driven diseases by promoting cellular cholesterol efflux pathways. However, current clinical application of these agents is hampered by concomitant LXR-induced activation of a lipogenic transcriptional network, leading to hepatic steatosis. Recent studies have suggested that protein arginine methyltransferase 3 (PRMT3) may act as a selective co-activator of LXR activity. Here, we verified the hypothesis that PRMT3 inhibition selectively disrupts the ability of LXR to stimulate lipogenesis while maintaining its capacity to modulate macrophage cholesterol homeostasis. EXPERIMENTAL APPROACH: A combination of the LXR agonist T0901317 and palm oil was administered to C57BL/6 mice to maximally stimulate LXR and PRMT3 activity. PRMT3 activity was inhibited using the allosteric inhibitor SGC707. KEY RESULTS: Treatment with SGC707 did not negatively influence the T0901317/palm oil-induced up-regulation of the cholesterol efflux ATP-binding cassette transporter genes, ABCA1 and ABCG1, in peritoneal cells. In contrast, SGC707 treatment was associated with a significant decrease in the hepatic expression of the lipogenic gene fatty acid synthase (-64%). A similar trend was observed for stearoyl-coenzyme A desaturase and acetyl CoA carboxylase expression (-43%; -56%). This obstruction of lipogenic gene transcription coincided with a significant 2.3-fold decrease in liver triglyceride content as compared with the T0901317 and palm oil-treated control group. CONCLUSION AND IMPLICATIONS: We showed that inhibition of PRMT3 activity by SGC707 treatment selectively impairs LXR-driven transcription of hepatic lipogenic genes, while the positive effect of LXR stimulation on macrophage cholesterol efflux pathways is maintained.

Naoxintong Retards Atherosclerosis by Inhibiting Foam Cell Formation Through Activating Pparα Pathway.

BACKGROUNDS: We recently reported that Naoxintong (NXT), a China Food and Drug Administration (FDA)-approved cardiac medicine, could reduce the plaque size, but the underlying mechanism remains elusive now. OBJECTIVE: In this study, we investigated the effects of NXT on foam cell accumulation both in vivo and in vitro and explored related mechanisms. METHOD: THP-1 cells and bone marrow-derived macrophages were incubated with oxidized low-density lipoprotein (ox-LDL) with/without Naoxintong. ApoE-/- mice fed an atherogenic diet were administered to receive NXT for eight weeks. Macrophage-derived foam cell formation in plaques was measured by immunohistochemical staining. Expression of proteins was evaluated by Western blot. Lentivirus was used to knockdown PPARα in THP-1 cells. RESULTS: After NXT treatment, foam cell accumulation was significantly reduced in atherosclerotic plaques. Further investigation revealed that oxidized low-density lipoprotein (ox-LDL) uptake was significantly decreased and expression of scavenger receptor class A (SR-A) and class B (SR-B and CD36) was significantly downregulated post-NXT treatment. On the other hand, NXT increased cholesterol efflux and upregulated ATP-binding cassette (ABC) transporters (ABCA-1 and ABCG-1) in macrophages. Above beneficial effects of NXT were partly abolished after lentiviral knockdown of PPARα. CONCLUSION: Our findings suggest that NXT could retard atherosclerosis by inhibiting foam cell formation through reducing ox-LDL uptake and enhancing cholesterol efflux and above beneficial effects are partly mediated through PPARα pathway.

Tetramethylpyrazine suppresses lipid accumulation in macrophages via upregulation of the ATP-binding cassette transporters and downregulation of scavenger receptors.

Tetramethylpyrazine (TMP), a biologically active ingredient first extracted from the Chinese medicinal plant Ligusticum wallichii Franchat., has athero-protective activity, yet the particular mechanisms have not been completely explored. The present study was designed to investigate the effect of TMP and its possible mechanisms in RAW264.7 macrophages and apolipoprotein E-deficient (ApoE-/-) mice. TMP treatment markedly increased the cholesterol efflux and inhibited oxidized low-density lipoprotein (ox-LDL) uptake, thus, ameliorating lipid accumulation in macrophages. In addition, TMP significantly increased the protein and mRNA expression of ATP-binding cassette transporters A1 (ABCA1) and G1 (ABCG1), while suppressing the protein and mRNA expression of class A scavenger receptor (SR-A) and the cluster of differentiation 36 (CD36). Moreover, the effects of TMP on the upregulation of the expression of ABCA1 and ABCG1, the downregulation of the expression of CD36 and SR-A, the increase of cholesterol efflux and the decrease of lipid accumulation as well as the uptake of ox-LDL were mediated by the inactivation of PI3K/Akt and p38 MAPK. Furthermore, TMP upregulated the protein stability of ABCA1 without affecting ABCG1. Accordingly, TMP regulated the expression of SR-A, CD36, ABCA1 and ABCG1 in aortas of ApoE-/- mice, which resembled the findings observed in macrophages. TMP was also capable of delaying the progression of atherosclerosis in ApoE-/- mice. These findings revealed that TMP downregulates scavenger receptors and upregulates ATP-binding cassette transporters via PI3K/Akt and p38 MAPK signaling, thus suppressing lipid accumulation in macrophages.

Cholesterol-lowering effect of Aralia elata (Miq.) Seem via the activation of SREBP-2 and the LDL receptor.

BACKGROUND: Hyperlipidemia causes arteriosclerosis, a risk factor for coronary heart disease. Prevention of hyperlipidemia by improving dietary habits has recently attracted attention. In this regard, we investigated whether Aralia elata (Miq.) Seem (AE) extract inhibits hepatic cholesterol accumulation and modulate the cellular signaling pathway. METHODS: To determine AE's cholesterol regulating mechanism, we measured cholesterol level, 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase activity and cholesterol regulating-related gene expression in HepG2 cells and in high-fat diet (HFD)-induced mice using ELISA and RT-PCR assay. RESULTS: The AE extract reduced cholesterol levels and HMG-CoA reductase activity in hepatocellular carcinoma HepG2 cells. In addition, it also reduced the plasma cholesterol concentrations in HFD-induced mice. Furthermore, the AE extract increased the gene expression of the LDL-receptor (LDL-R); sterol-regulatory-element binding protein-2 (SREBP-2); ATP-binding cassette, sub-family A, member 1 (ABCA1); and scavenger receptor class B member 1 (SR-B1) in a dose-dependent manner. However, the AE extract did not affect the gene expression of acetyl-coenzyme A acetyltransferase (ACAT) in either the HepG2 cells or mice. CONCLUSION: We demonstrated that the AE extract activated genes related to cholesterol metabolism, such as SREBP-2 and LDL-R, which resulted in hypocholesterolemic activities.

Pectin penta-oligogalacturonide reduces cholesterol accumulation by promoting bile acid biosynthesis and excretion in high-cholesterol-fed mice.

Haw pectin penta-oligogalacturonide (HPPS) has important role in improving cholesterol metabolism and promoting the conversion of cholesterol to bile acids (BA) in mice fed high-cholesterol diet (HCD). However, the mechanism is not clear. This study aims to investigate the effects of HPPS on cholesterol accumulation and the regulation of hepatic BA synthesis and transport in HCD-fed mice. Results showed that HPPS significantly decreased plasma and hepatic TC levels but increased plasma high-density lipoprotein cholesterol (HDL-C) and apolipoprotein A-I (apoA-I) levels, compared to HCD. BA analysis showed that HPPS markedly decreased hepatic and small intestine BA levels but increased the gallbladder BA levels, and finally decreased the total BA pool size, compared to HCD. Studies of molecular mechanism revealed that HPPS promoted hepatic ATP-binding cassette transporter A1 (ABCA1), ATP-binding cassette transporter G1 (ABCG1), and scavenger receptor BI (SR-BI) expression but did not affect ATB binding cassette transporter G5/G8 (ABCG5/8) expression. HPPS inactivated hepatic farnesoid X receptor (FXR) and target genes expression, which resulted in significant increase of cholesterol 7α-hydroxylase 1 (CYP7A1) and sterol 12α-hydroxylase (CYP8B1) expression, with up-regulations of 204.2% and 33.5% for mRNA levels, respectively, compared with HCD. In addition, HPPS markedly enhanced bile salt export pump (BSEP) expression but didn't affect the sodium/taurocholate co-transporting polypeptide (NTCP) expression. In conclusion, the study revealed that HPPS reduced cholesterol accumulation by promoting BA synthesis in the liver and excretion in the feces, and might promote macrophage-to-liver reverse cholesterol transport (RCT) but did not liver-to-fecal RCT.

Regression of atherosclerosis with apple procyanidins by activating the ATP-binding cassette subfamily A member 1 in a rabbit model.

BACKGROUND AND AIMS: Apple polyphenol contains abundant procyanidins, which have been associated with an anti-atherosclerosis and cholesterol-lowering effect. The aim of this study was to investigate whether apple procyanidins (APCs) feature therapeutic efficacy in terms of regressing atherosclerosis and whether this efficacy is due to mechanisms other than a cholesterol-lowering effect. METHODS: After eight weeks on an atherogenic diet, rabbits were given a normal diet for another eight weeks to normalize the increased serum lipids level. The rabbits in the baseline group were sacrificed at this stage. The control group was subsequently fed a normal diet for eight weeks, while the APCs group was administrated 50 mg/kg/day of APCs in addition to the normal diet. Serum lipids and aortic intimal-medial thickness (IMT) were serially examined, and the resected aorta was examined histologically and through molecular biology. RESULTS: Aortic IMT on ultrasonography and the lipid accumulation area examined using Sudan IV staining were significantly reduced in the APCs group as compared to the control group. Serum lipid profiles were not different between the groups. Immunohistochemistry showed significantly decreased staining of an oxidative stress marker and significantly increased staining of ATP-binding cassette subfamily A member 1 (ABCA1) in the APCs group. Western blotting and RT-PCR also showed increased expression of ABCA1 mRNA and its protein in the APCs group. CONCLUSIONS: This study revealed that APCs administration causes a regression of atherosclerosis. APCs might hold promise as an anti-atherosclerotic agent.

Lychee pulp phenolics ameliorate hepatic lipid accumulation by reducing miR-33 and miR-122 expression in mice fed a high-fat diet.

Dietary phenolics exhibit hypolipidemic activity by changing lipid metabolism-related microRNA (miRNA) expression. Quercetin 3-O-rutinoside-7-O-α-l-rhamnosidase (quercetin 3-rut-7-rha), rutin and (-)-epicatechin are the main phenolics in lychee (Litchi chinensis Sonn.) pulp. A previous study reported that quercetin 3-rut-7-rha and rutin had hypolipidemic effects. To elucidate these effects and the underlying molecular mechanisms of lychee pulp phenolics (LPPs), the hepatic mRNA and protein expression of lipid metabolism-related genes and their associated miRNAs were measured after ten weeks of treatment with a high-fat diet (HFD) alone or in combination with LPPs. The administration of LPPs significantly reduced the HFD-induced increase in serum total cholesterol and triglyceride levels but increased the HDL-c content. The mRNA and protein expression levels of hepatic adenosine triphosphate-binding cassette transporter A1 (ABCA1) and carnitine palmitoyltransferase 1a (CPT1a) were upregulated, while fatty acid synthase (FAS) mRNA and the corresponding protein expression levels were downregulated by LPPs. Furthermore, the expression levels of miR-33, which directly modulates ABCA1 and CPT1a, and miR-122, which indirectly regulates FAS, were downregulated in mouse hepatocytes. The repression of miR-33 and miR-122 is a possible molecular mechanism of the hypolipidemic effects of LPPs in the liver. Our results suggest a novel hypolipidemic mechanism of LPPs.

9-cis ß-Carotene Increased Cholesterol Efflux to HDL in Macrophages.

Cholesterol efflux from macrophages is a key process in reverse cholesterol transport and, therefore, might inhibit atherogenesis. 9-cis-ß-carotene (9-cis-ßc) is a precursor for 9-cis-retinoic-acid (9-cis-RA), which regulates macrophage cholesterol efflux. Our objective was to assess whether 9-cis-ßc increases macrophage cholesterol efflux and induces the expression of cholesterol transporters. Enrichment of a mouse diet with ßc from the alga Dunaliella led to ßc accumulation in peritoneal macrophages. 9-cis-ßc increased the mRNA levels of CYP26B1, an enzyme that regulates RA cellular levels, indicating the formation of RA from ßc in RAW264.7 macrophages. Furthermore, 9-cis-ßc, as well as all-trans-ßc, significantly increased cholesterol efflux to high-density lipoprotein (HDL) by 50% in RAW264.7 macrophages. Likewise, food fortification with 9-cis-ßc augmented cholesterol efflux from macrophages ex vivo. 9-cis-ßc increased both the mRNA and protein levels of ABCA1 and apolipoprotein E (APOE) and the mRNA level of ABCG1. Our study shows, for the first time, that 9-cis-ßc from the diet accumulates in peritoneal macrophages and increases cholesterol efflux to HDL. These effects might be ascribed to transcriptional induction of ABCA1, ABCG1, and APOE. These results highlight the beneficial effect of ßc in inhibition of atherosclerosis by improving cholesterol efflux from macrophages.

Water-Soluble Components of Sesame Oil Reduce Inflammation and Atherosclerosis.

Atherosclerosis, a major form of cardiovascular disease, is now recognized as a chronic inflammatory disease. Nonpharmacological means of treating chronic diseases have gained attention recently. We previously reported that sesame oil aqueous extract (SOAE) has anti-inflammatory properties, both in vitro and in vivo. In this study, we have investigated the antiatherosclerotic properties of SOAE, and the mechanisms, through genes and inflammatory markers, by which SOAE might modulate atherosclerosis. Low-density lipoprotein receptor (LDL-R) knockout female mice were fed with either a high-fat (HF) diet or an HF diet supplemented with SOAE. Plasma lipids and atherosclerotic lesions were quantified after 3 months of feeding. Plasma samples were used for global cytokine array. RNA was extracted from both liver tissue and the aorta, and used for gene analysis. The high-fat diet supplemented with SOAE significantly reduced atherosclerotic lesions, plasma cholesterol, and LDL cholesterol levels in LDL-R(-/-) mice. Plasma inflammatory cytokines were reduced in the SOAE diet-fed animals, but not significantly, demonstrating potential anti-inflammatory properties of SOAE. Gene analysis showed the HF diet supplemented with SOAE reduced gene expression involved in inflammation and induced genes involved in cholesterol metabolism and reverse cholesterol transport, an anti-inflammatory process. Our studies suggest that a SOAE-enriched diet could be an effective nonpharmacological treatment for atherosclerosis by controlling inflammation and regulating lipid metabolism.