Scavenger Receptor Class B Member 1 Research Articles

Relative Uptake of Tomato Carotenoids by In Vitro Intestinal and Prostate Cancer Cells

BackgroundConsumption of tomatoes and tomato carotenoids is associated with a reduced risk of prostate cancer. Prostate tissue accumulates tomato carotenoids, including lycopene, β-carotene, and phytoene. Phytoene accumulation is relatively greater in the prostate than that of lycopene, but the metabolic determinants of tissue carotenoid profiles are poorly understood. ObjectivesThe purpose of this study was to determine if differences in stability, cellular uptake, and clearance of phytoene compared with lycopene or β-carotene by prostate and intestinal cells may explain differences in observed tissue carotenoid profiles. MethodsGene and protein expression for carotenoid metabolism in prostate cell lines were analyzed by qRT-PCR and Western blot, respectively. Uptake, efflux, and clearance of phytoene, lycopene, or β-carotene by prostate cell (LNCaP, RWPE-1, and PC-3) and absorptive enterocyte (Caco-2) cultures were compared. The effect of scavenger receptor class B member 1 (SCARB1) inhibition on carotenoid uptake by LNCaP, RWPE-1, and Caco-2 cells was tested. ResultsSCARB1 was expressed across prostate cell lines. Lycopene, phytoene, and β-carotene uptakes were similar in LNCaP and PC-3 cells, whereas RWPE-1 cells absorbed a smaller portion of the phytoene dose than lycopene or β-carotene doses. The clearance rates of carotenoids from LNCaP cells did not differ. Intestinal cell uptake of phytoene was greatest, followed by β-carotene and lycopene. SR-BI inhibitor treatment did not significantly reduce the uptake or efflux of carotenoids by LNCaP or Caco-2 cells at the dose concentration provided. ConclusionsOverall, this study suggests that greater bioavailability at the point of the intestine and greater stability of phytoene are determinants of the relative enrichment of phytoene in prostate tissue.

SCARB1-encoded circ _0029343 induces p73 splicing to promote growth and metastasis of hepatocellular carcinoma via miR-486-5p/SRSF3 axis.

Circular RNAs (circRNAs) exhibit essential regulation in the malignant development of hepatocellular carcinoma (HCC). This study aims to investigate the physiological mechanisms of circ_0029343 encoded by scavenger receptor class B member 1 (SCARB1) involved in the growth and metastasis of HCC. Differentially expressed mRNAs in HCC were obtained, followed by the prediction of target genes of differentially expressed miRNAs and gene ontology and kyoto encyclopedia of genes and genomes analysis on the differentially expressed mRNAs. Moreover, the regulatory relationship between circRNAs encoded by SCARB1 and differentially expressed miRNAs was predicted. In vitro cell experiments were performed to verify the effects of circ_0029343, miR-486-5p, and SRSF3 on the malignant features of HCC cells using the gain- or loss-of-function experiments. Finally, the effects of circ_0029343 on the growth and metastasis of HCC cells in xenograft mouse models were also explored. It was found that miR-486-5p might interact with seven circRNAs encoded by SCARB1, and its possible downstream target gene was SRSF3. Moreover, SRSF3 was associated with the splicing of various RNA. circ_0029343 could sponge miR-486-5p to up-regulate SRSF3 and activate PDGF-PDGFRB (platelet-derived growth factor and its receptor, receptor beta)signaling pathway by inducing p73 splicing, thus promoting the proliferation, migration, and invasion and inhibiting apoptosis of HCC cells. In vivo, animal experiments further confirmed that overexpression of circ_0029343 could promote the growth and metastasis of HCC cells in nude mice. circ_0029343 encoded by SCARB1 may induce p73 splicing and activate thePDGF-PDGFRB signaling pathway through the miR-486-5p/SRSF3 axis, thus promoting the growth and metastasis of HCC cells.

H19 recruited N 6 -methyladenosine (m 6 A) reader YTHDF1 to promote SCARB1 translation and facilitate angiogenesis in gastric cancer.

Angiogenesis is described as a complex process in which new microvessels sprout from endothelial cells of existing vasculature. This study aimed to determine whether long non-coding RNA (lncRNA) H19 induced the angiogenesis of gastric cancer (GC) and its possible mechanism. Gene expression level was determined by quantitative real-time polymerase chain reaction and western blotting. Cell counting kit-8, transwell, 5-Ethynyl-2'-deoxyuridine (EdU), colony formation assay, and human umbilical vein endothelial cells (HUVECs) angiogenesis assay as well as Matrigel plug assay were conducted to study the proliferation, migration, and angiogenesis of GC in vitro and in vivo . The binding protein of H19 was found by RNA pull-down and RNA Immunoprecipitation (RIP). High-throughput sequencing was performed and next Gene Ontology (GO) as well as Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis was conducted to analyze the genes that are under H19 regulation. Methylated RIP (me-RIP) assay was used to investigate the sites and abundance among target mRNA. The transcription factor acted as upstream of H19 was determined through chromatin immunoprecipitation (ChIP) and luciferase assay. In this study, we found that hypoxia-induced factor (HIF)-1α could bind to the promoter region of H19, leading to H19 overexpression. High expression of H19 was correlated with angiogenesis in GC, and H19 knocking down could inhibit cell proliferation, migration and angiogenesis. Mechanistically, the oncogenic role of H19 was achieved by binding with the N 6 -methyladenosine (m 6 A) reader YTH domain-containing family protein 1 (YTHDF1), which could recognize the m 6 A site on the 3'-untransated regions (3'-UTR) of scavenger receptor class B member 1 (SCARB1) mRNA, resulting in over-translation of SCARB1 and thus promoting the proliferation, migration, and angiogenesis of GC cells. HIF-1α induced overexpression of H19 via binding with the promoter of H19, and H19 promoted GC cells proliferation, migration and angiogenesis through YTHDF1/SCARB1, which might be a beneficial target for antiangiogenic therapy for GC.

Association Analysis Between Methylation of SCARB1 Gene Promoter and Coronary Heart Disease

Objective To explore the relationship between scavenger receptor class B member 1 (SCARB1) gene promoter methylation and the pathogenesis of coronary artery disease. Methods A total of 120 patients with coronary heart disease treated in Renji Hospital affiliated to Shanghai Jiao Tong University School of Medicine from December 2018 to May 2020 were selected as the case group,while 140 gender and age matched healthy participants were randomly selected as the control group for a case-control study.The methylation status was detected by high-throughput target sequencing after bisulfite converting,and the methylation of CpG sites in the promoter region of SCARB1 gene was compared between the two groups. Results The case group showed higher methylation level of SCARB1+67 and lower methylation level of SCARB1+134 than the control group (both P<0.001),and the differences remained statistically significant in men (both P<0.001) and women (both P<0.001).The overall methylation level in the case group was lower than that in the control group [(80.27±2.14)% vs.(81.11±1.27)%;P=0.006],while this trend was statistically significant only in men (P=0.002). Conclusion The methylation of SCARB1 gene promotor is associated with the pathogenesis and may participate in the occurrence and development of coronary heart disease.

Cholesterol supports bovine granulosa cell inflammatory responses to lipopolysaccharide.

Bovine granulosa cells need to be cultured with serum to generate inflammation in response to bacterial lipopolysaccharide. This study shows that it is cholesterol that facilitates this lipopolysaccharide-stimulated cytokine secretion. During bacterial infections of the bovine uterus or mammary gland, ovarian granulosa cells mount inflammatory responses to lipopolysaccharide (LPS). In vitro, LPS stimulates granulosa cell secretion of the cytokines IL-1α and IL-1β and the chemokine IL-8. These LPS-stimulated inflammatory responses depend on culturing granulosa cells with serum, but the mechanism is unclear. Here, we tested the hypothesis that cholesterol supports inflammatory responses to LPS in bovine granulosa cells. We used granulosa cells isolated from 4 to 8 mm and >8.5 mm diameter ovarian follicles and manipulated the availability of cholesterol. We found that serum or follicular fluid containing cholesterol increased LPS-stimulated secretion of IL-1α and IL-1β from granulosa cells. Conversely, depleting cholesterol using methyl-β-cyclodextrin diminished LPS-stimulated secretion of IL-1α, IL-1β and IL-8 from granulosa cells cultured in serum. Follicular fluid contained more high-density lipoprotein cholesterol than low-density lipoprotein cholesterol, and granulosa cells expressed the receptor for high-density lipoprotein, scavenger receptor class B member 1 (SCARB1). Furthermore, culturing granulosa cells with high-density lipoprotein cholesterol, but not low-density lipoprotein or very low-density lipoprotein cholesterol, increased LPS-stimulated inflammation in granulosa cells. Cholesterol biosynthesis also played a role in granulosa cell inflammation because RNAi of mevalonate pathway enzymes inhibited LPS-stimulated inflammation. Finally, treatment with follicle-stimulating hormone, but not luteinising hormone, increased LPS-stimulated granulosa cell inflammation, and follicle-stimulating hormone increased SCARB1 protein. However, changes in inflammation were not associated with changes in oestradiol or progesterone secretion. Taken together, these findings imply that cholesterol supports inflammatory responses to LPS in granulosa cells.

Effects of Midazolam on the Development of Adult Leydig Cells From Stem Cells In Vitro.

BackgroundMidazolam is a neurological drug with diverse functions, including sedation, hypnosis, decreased anxiety, anterograde amnesia, brain-mediated muscle relaxation, and anticonvulsant activity. Since it is frequently used in children and adolescents for extended periods of time, there is a risk that it may affect their pubertal development. Here, we report a potential effect of the drug on the development of Leydig cells (LCs), the testosterone (T)-producing cells in the testis.MethodsStem LCs (SLCs), isolated from adult rat testes by a magnetic-activated cell sorting technique, were induced to differentiate into LCs in vitro for 3 weeks. Midazolam (0.1–30 μM) was added to the culture medium, and the effects on LC development were assayed.ResultsMidazolam has dose-dependent effects on SLC differentiation. At low concentrations (0.1–5 μM), the drug can mildly increase SLC differentiation (increased T production), while at higher concentrations (15–30 μM), it inhibits LC development (decreased T production). T increases at lower levels may be due to upregulations of scavenger receptor class b Member 1 (SCARB1) and cytochrome P450 17A1 (CYP17A1), while T reductions at higher levels of midazolam could be due to changes in multiple steroidogenic proteins. The uneven changes in steroidogenic pathway proteins, especially reductions in CYP17A1 at high midazolam levels, also result in an accumulation of progesterone. In addition to changes in T, increases in progesterone could have additional impacts on male reproduction. The loss in steroidogenic proteins at high midazolam levels may be mediated in part by the inactivation of protein kinase B/cAMP response element-binding protein (AKT/CREB) signaling pathway.ConclusionMidazolam has the potential to affect adult Leydig cell (ALC) development at concentrations comparable with the blood serum levels in human patients. Further studies are needed to test the effects on human cells.

Establishment and characterization of a highly metastatic human osteosarcoma cell line from osteosarcoma lung metastases

OS (Osteosarcoma) is the most common malignant tumor in adolescents, and lung metastasis limits its therapeutic outcome. The present study aimed to establish a highly metastatic human OS cell line directly from lung metastases and characterize its biological functions. In this study, epithelioid tumor cells with large nucleo-cytoplasmic ratio and abundant organelles were obtained by the tissue mass adherent and repeated digestion adherent method and named ZOSL-1 cells. ZOSL-1 cells had the potential to proliferate in vitro with a doubling time of 39.28 ± 3.04 h and migrate with or without a matrix. ZOSL-1 cells were tumorigenic in vivo, and had the ability to develop lung metastasis after intratibial injection. ZOSL-1 cells expressed the osteogenic-related genes osteocalcin and osteopontin. In addition, the expression of ZOSL-1 in Fas cell surface death receptor (FAS), CD44 molecule (CD44), GNAS complex locus (GNAS), scavenger receptor class B member 1 (SCARB1), C-X-C motif chemokine receptor 4 (CXCR4), cadherin 11 (CDH11), neurofibromin 2 (NF2) and ezrin (EZR) genes may be related to its transfer efficiency. Taken together, these results indicated the high metastatic capability and important biological functions of ZOSL-1 cells. ZOSL-1 establishment provided a relevant model for the study of osteosarcoma lung metastasis.

Inhibition of microRNA-128-3p attenuates hypercholesterolemia in mouse model

AimsHypercholesterolemia remains a critical risk factor for cardiovascular diseases and there is an urgent need to develop effective alternative therapeutics. Herein, we investigated the effects of miR-128-3p inhibition on serum cholesterol levels using a hypercholesterolemic mouse model. Materials and methodsFive injections of anti-miR-128-3p (AM-128) treatment were given, and the cholesterol profile in serum and liver was quantified. We validated the underlying gene network using qRT-PCR, western blotting, ELISA, and dual luciferase assays. Key findingsAM-128 treatment inhibits cholesterol biosynthesis by upregulating INSIG1 and downregulating HMGCR (3-hydroxy-3-methylglutaryl-CoA reductase) expression. The serum cholesterol clearance by SR-B1 (scavenger receptor class B member 1) and LDLR (low density lipoprotein receptors) was also increased. Furthermore, the catabolism of cholesterol by CYP7A1 (cytochrome P450 family 7 subfamily A member 1) was increased. SignificanceOur results confirmed a critical role of miR-128-3p inhibition in lowering serum cholesterol and suggest its potential therapeutic implications in reversing hypercholesterolemia.

Homocysteine accelerates atherosclerosis by inhibiting scavenger receptor class B member1 via DNMT3b/SP1 pathway

Homocysteine (Hcy) is an independent risk factor for atherosclerosis, which is characterized by lipid accumulation in the atherosclerotic plaque. Increasing evidence supports that as the main receptor of high-density lipoprotein, scavenger receptor class B member 1 (SCARB1) is protective against atherosclerosis. However, the underlying mechanism regarding it in Hcy-mediated atherosclerosis remains unclear. Here, we found the remarkable inhibition of SCARB1 expression in atherosclerotic plaque and Hcy-treated foam cells, whereas overexpression of SCARB1 can suppress lipid accumulation in foam cells following Hcy treatment. Analysis of SCARB1 promoter showed that no significant change of methylation level was observed both in vivo and in vitro under Hcy treatment. Moreover, it was found that the negative regulation of DNMT3b on SCARB1 was due to the decreased recruitment of SP1 to SCARB1 promoter. Thus, we concluded that inhibition of SCARB1 expression induced by DNMT3b at least partly accelerated Hcy-mediated atherosclerosis through promoting lipid accumulation in foam cells, which was attributed to the decreased binding of SP1 to SCARB1 promoter. In our point, these findings will provide novel insight into an epigenetic mechanism for atherosclerosis.

An exploration of antigen expression of hepatitis C entry receptors on equine cells in relation to equine hepacivirus A

Equine hepacivirus A (EqHV) belongs to the family Flaviviridae and has been identified as the hepacivirus phylogenetically most closely related to Hepatitis C virus (HCV). Like HCV, EqHV is a hepatotropic virus that has been reported in over fourteen countries from six continents. It has a high prevalence in some populations, in particular the Thoroughbred breed. However, much is still unknown about EqHV, such as its pathogenesis and mode of transmission. The main four receptors used by HCV for viral entry to human hepatocytes are Cluster of Differentiation-81 (CD-81), occludin (OCLN), claudin-1 (CLDN-1) and Scavenger Receptor Class B Member 1 (SCAR-B1). This study investigated the distribution and expression of these entry receptors on equine cells by flow cytometry, immunocytochemistry and immunohistochemistry. Using a human liver cell line (Huh-7) as a positive control, antibodies against HCV receptors appeared to cross-react with antigens on equine cells. The proportion of fetal horse kidney cells that expressed CD-81, OCLN, and CLDN-1 was 37.2 %, 16.0 %, and 7.0 %, respectively, whereas the equine dermal cells (E.Derms) expressed CD-81 (96.0 %), OCLN (1.2 %) and CLDN-1 (1.7 %). CD-81, OCLN and CLDN-1 were also expressed on E.Derms and Huh7 cells, as detected by immunocytochemistry and on equine liver cells and the allantochorionic region of Thoroughbred placenta by immunohistochemistry. These findings form the basis for further comparative investigation into the entry receptors used by EqHV to infect equine and human cells. Such information may inform future studies on EqHV pathogenesis and mode(s) of transmission.

SCARB1 rs5888 gene polymorphisms in coronary heart disease: A systematic review and a meta-analysis

BackgroundStudies have suggested that high-density lipoprotein (HDL) stimulates scavenger receptor class B type 1 (SR-B1) to promote hepatic uptake of cholesterol. SR-B1 is encoded by scavenger receptor class B member 1 (SCARB1) gene in human. A rare mutation in SCARB1 gene has been associated with coronary heart disease (CHD). A polymorphism rs5888 of SCARB1 gene has been linked to CHD risk in humans. ObjectivesThe objective was to investigate the relationship between the SCARB1 gene polymorphism rs5888 and risk of CHD. MethodsWe searched databases of case-control studies and cohort studies on rs5888 polymorphism of SCARB1 gene and risk of CHD. Two reviewers independently screened literature, extracted data, and estimated potential bias of included studies. The quality of the studies was evaluated by recommendation of Newcastle-Ottawa Scale (NOS). Meta-analysis was performed with Stata 12.0 software. ResultsSeven studies including 6360 subjects (cases: 2456, controls: 3904) were included in the final data combination. Meta-analysis showed T allele had a lower risk of CHD as compared to C allele in allele model (T vs. C: OR = 0.87, 95% CI: 0.70 to 1.09, P = 0.229). Moreover, we found that T allele or TT/TC had a lower risk of CHD as compared to C/CC in male in allele model (T vs. C: OR = 0.79, 95% CI: 0.61 to 1.01). However, no significant association was observed in women in all allele models. ConclusionsOur findings suggested that polymorphism rs5888 had negative association with CHD, especially in male. However, the conclusion needs further verification with high quality studies with larger sample size and rigorous designs.

Correlation of CD81 and SCARB1 polymorphisms on virological responses in Iranian patients with chronic hepatitis C virus genotype 1

The cluster of differentiation 81 (CD81) and scavenger receptor class B member 1 (SCARB1) plays an important role in the entry of hepatitis C virus (HCV). We assessed the correlation of five single nucleotide polymorphisms (SNPs) of CD81 (rs800136, rs2651842, rs2522012, rs800146, and rs708564) and SCARB1 rs10846744 polymorphisms with treatment responses in 395 treatment-naïve patients with chronic HCV (CHC) genotype 1 treated with pegylated interferon-α and ribavirin (pegIFN-α/RBV). The frequency of rapid virologic response (RVR), complete early virologic response (cEVR) and sustained virologic response (SVR) were 57.2%, 55.2%, and 58.2%, respectively. RVR, cEVR, and SVR were significantly associated with CD81 rs800136 (CC), CD81 rs2651842 (AA), CD81 rs708564 (TT), and SCARB1 rs10846744 (CC). High rates of RVR, cEVR, and SVR were reported for the CD81 rs800136 (CC), CD81 rs2651842 (AA), and CD81 rs708564 (TT) genotypes when correlated with higher levels of low-density lipoprotein (LDL) and lower levels of high-density lipoprotein (HDL) as well as lower levels of HDL and LDL in the SCARB1 rs10846744 (CC) genotype. In addition, patients with GG genotype had higher fasting blood glucose (FBS) level than those with CC genotype. In conclusion, CD81 and SCARB1 SNPs may serve as powerful predictor factors for treatment responses in CHC patients, and this effect is correlated with serum lipoprotein and FBS levels.

ABCA1-Derived Nascent High-Density Lipoprotein-Apolipoprotein AI and Lipids Metabolically Segregate.

Reverse cholesterol transport comprises cholesterol efflux from ABCA1-expressing macrophages to apolipoprotein (apo) AI, giving nascent high-density lipoprotein (nHDL), esterification of nHDL-free cholesterol (FC), selective hepatic extraction of HDL lipids, and hepatic conversion of HDL cholesterol to bile salts, which are excreted. We tested this model by identifying the fates of nHDL-[3H]FC, [14C] phospholipid (PL), and [125I]apo AI in serum in vitro and in vivo. During in vitro incubation of human serum, nHDL-[3H]FC and [14C]PL rapidly transfer to HDL and low-density lipoproteins (t1/2=2-7 minutes), whereas nHDL-[125I]apo AI transfers solely to HDL (t1/2<10 minutes) and to the lipid-free form (t1/2>480 minutes). After injection into mice, nHDL-[3H]FC and [14C]PL rapidly transfer to liver (t1/2=≈2-3 minutes), whereas apo AI clears with t1/2=≈460 minutes. The plasma nHDL-[3H]FC esterification rate is slow (0.46%/h) compared with hepatic uptake. PL transfer protein enhances nHDL-[14C]PL but not nHDL-[3H]FC transfer to cultured Huh7 hepatocytes. nHDL-FC, PL, and apo AI enter different pathways in vivo. Most nHDL-[3H]FC and [14C]PL are rapidly extracted by the liver via SR-B1 (scavenger receptor class B member 1) and spontaneous transfer; hepatic PL uptake is promoted by PL transfer protein. nHDL-[125I]apo AI transfers to HDL and to the lipid-free form that can be recycled to nHDL formation. Cholesterol esterification by lecithin:cholesterol acyltransferase is a minor process in nHDL metabolism. These findings could guide the design of therapies that better mobilize peripheral tissue-FC to hepatic disposal.

Scavenger receptor class B member 1 (SCARB1) variants modulate hepatitis C virus replication cycle and viral load

There are numerous coding and non-coding variants in the SCARB1 gene that encodes scavenger receptor class B member 1 (SR-BI), a key receptor for both high density lipoproteins and hepatitis C virus (HCV). Many have been linked to clinical phenotypes, yet their impact on the HCV replication cycle is incompletely understood. The aim of this study was to analyze the impact of these variants on the molecular biology and clinical course of HCV. We analyzed key coding non-synonymous as well as non-coding SCARB1 variants using virological in vitro and human genetics approaches. Non-synonymous variants: S112F and T175A have greatly reduced HCV receptor function. When present on the cell surface, these variants are impaired in their ability to interact with HCV E2. Non-coding variants: The G allele in rs3782287 is associated with decreased viral load. Haplotype analysis confirmed these findings and identified haplotype rs3782287 A/rs5888 C as a risk allele associated with increased viral load. We also detected a trend towards lower hepatic SR-BI expression in individuals with the rs3782287 GG genotype associated with low viral load suggesting a potential underlying mechanism. Coding and non-coding genetic SCARB1 variants modulate the HCV replication cycle and possibly clinical features of hepatitis C. These findings underscore the relevance of SR-BI as an HCV receptor and contribute to our understanding of inter-individual variation in HCV infection. The cell surface receptor SR-BI (scavenger receptor class B member 1), is essential for hepatitis C virus (HCV) entry into hepatocytes. Variations in the gene coding this receptor influence infectivity and viral load. We analyzed these variations to gain a better understanding of inter-individual differences over the course of HCV infection.

Common SNP rs6564851 in the BCO1 Gene Affects the Circulating Levels of β-Carotene and the Daily Intake of Carotenoids in Healthy Japanese Women.

The circulating levels of β-carotene are modulated not only by sex, but also by autosomal gene variations and fruit intake. The aim of this study was to investigate the interactions between β-carotene metabolism-related gene single nucleotide polymorphisms (SNPs; genetic factors) and nutrient intake (environmental factors) relating to their effects on circulating β-carotene. The serum concentrations of β-carotene and the habitual food intake of 92 healthy Japanese adults were examined. All subjects were genotyped for three common SNPs: rs6564851 in the β-carotene 15,15′-oxygenase 1 (BCO1) gene, rs2278986 in the scavenger receptor class B member 1 (SCARB1) gene and rs362090 in the intestine-specific homeobox (ISX) gene. Univariate analysis revealed that the circulating β-carotene levels were significantly higher in rs6564851 GG homozygotes (p = 0.003). Additionally, the daily intake of β-cryptoxanthin was positively associated with the circulating β-carotene levels in female GG homozygotes of rs6564851 (p = 0.023), and the daily intake of α- and β-carotenes, and β-cryptoxanthin was significantly lower in female rs6564851 T allele carries than in female GG homozygotes (p = 0.009, 0.008, 0.009, respectively). The present study apparently indicates that higher circulating β-carotene levels in female rs6564851 GG homozygotes depend on carotenoid intake.

Pediococcus acidilactici LAB4 and Lactobacillus plantarum LAB12 assimilate cholesterol and modulate ABCA1, CD36, NPC1L1 and SCARB1 in vitro.

There is growing interest in the use of probiotic lactic acid bacteria (LAB) for prevention of hypercholesterolaemia. This study assessed the cholesterol lowering ability of Pediococcus acidilactici LAB4 and Lactobacillus plantarum LAB12 in growth media. Both LAB yielded >98% (39.2 μg/ml) cholesterol lowering in growth media. Nile Red staining indicated direct assimilation of cholesterol by the LAB. The LAB were then explored for their prophylactic (pre-treatment of HT29 cells with LAB prior to cholesterol exposure) and biotherapeutic (treatment of HT29 cells with LAB after exposure to cholesterol) use against short and prolonged exposure of HT29 cells to cholesterol, respectively. For HT29 cells pre-treated with LAB, cholesterol lowering was accompanied by down-regulation of ATP-binding cassette family transporter-type A1 (ABCA1), cluster of differentiation 36 (CD36) and scavenger receptor class B member 1 (SCARB1). HT29 cells treated with LAB after prolonged exposure to cholesterol source, on the other hand, was associated with up-regulation of ABCA1, restoration of CD36 to basal level and down-regulation of Neimann-Pick C1-Like 1 (NPC1L1). The present findings implied the potential use of LAB4 and LAB12 as part of the strategies in prevention and management of hypercholesterolaemia.

Genetic contribution of SCARB1 variants to lipid traits in African Blacks: a candidate gene association study.

BackgroundHigh-density lipoprotein cholesterol (HDL-C) exerts many anti-atherogenic properties including its role in reverse cholesterol transport (RCT). Scavenger receptor class B member 1 (SCARB1) plays a key role in RCT by selective uptake of HDL cholesteryl esters. We aimed to explore the genetic contribution of SCARB1 to affecting lipid levels in African Blacks from Nigeria.MethodsWe resequenced 13 exons and exon-intron boundaries of SCARB1 in 95 individuals with extreme HDL-C levels using Sanger method. Then, we genotyped 147 selected variants (78 sequence variants, 69 HapMap tagSNPs, and 2 previously reported relevant variants) in the entire sample of 788 African Blacks using either the iPLEX Gold or TaqMan methods. A total of 137 successfully genotyped variants were further evaluated for association with major lipid traits.ResultsThe initial gene-based analysis demonstrated evidence of association with HDL-C and apolipoprotein A-I (ApoA-I). The follow-up single-site analysis revealed nominal evidence of novel associations of nine common variants with HDL-C and/or ApoA-I (P < 0.05). The strongest association was between rs11057851 and HDL-C (P = 0.0043), which remained significant after controlling for multiple testing using false discovery rate. Rare variant association testing revealed a group of 23 rare variants (frequencies ≤1 %) associated with HDL-C (P = 0.0478). Haplotype analysis identified four SCARB1 regions associated with HDL-C (global P < 0.05).ConclusionsTo our knowledge, this is the first report of a comprehensive association study of SCARB1 variations with lipid traits in an African Black population. Our results showed the consistent association of SCARB1 variants with HDL-C across various association analyses, supporting the role of SCARB1 in lipoprotein-lipid regulatory mechanism.Electronic supplementary materialThe online version of this article (doi:10.1186/s12881-015-0250-6) contains supplementary material, which is available to authorized users.

Intratumor cholesteryl ester accumulation is associated with human breast cancer proliferation and aggressive potential: a molecular and clinicopathological study.

BackgroundThe metabolic effect of intratumor cholesteryl ester (CE) in breast cancer remains poorly understood. The objective was to analyze the relationship between intratumor CE content and clinicopathological variables in human breast carcinomas.MethodsWe classified 30 breast carcinoma samples into three subgroups: 10 luminal-A tumors (ER+/PR+/Her2-), 10 Her-2 tumors (ER-/PR-/Her2+), and 10 triple negative (TN) tumors (ER-/PR-/Her2-). We analyzed intratumor neutral CE, free cholesterol (FC) and triglyceride (TG) content by thin layer chromatography after lipid extraction. RNA and protein levels of lipid metabolism and invasion mediators were analyzed by real time PCR and Western blot analysis.ResultsGroup-wise comparisons, linear regression and logistic regression models showed a close association between CE-rich tumors and higher histologic grade, Ki-67 and tumor necrosis. CE-rich tumors displayed higher mRNA and protein levels of low-density lipoprotein receptor (LDLR) and scavenger receptor class B member 1 (SCARB1). An increased expression of acetyl-Coenzyme A acetyltransferase 1 (ACAT1) in CE-rich tumors was also reported.ConclusionsIntratumor CE accumulation is intimately linked to proliferation and aggressive potential of breast cancer tumors. Our data support the link between intratumor CE content and poor clinical outcome and open the door to new antitumor interventions.Electronic supplementary materialThe online version of this article (doi:10.1186/s12885-015-1469-5) contains supplementary material, which is available to authorized users.

Genetic Variation Predicts Serum Lycopene Concentrations in a Multiethnic Population of Postmenopausal Women ,

Background: The consumption and blood concentrations of lycopene are both positively and inversely associated with the risk of several chronic diseases. The inconsistences in lycopene disease association studies may stem from a lack of knowledge about the genetic variation in the synthesis, metabolism, and deposition of transport and binding proteins, which potentially influence serum lycopene concentrations.Objective: We examined the association between variation across the genome and serum concentrations of lycopene in a multiethnic population.Methods: Participants included African (n = 914), Hispanic (n = 464), and European (n = 1203) American postmenopausal women from the Women’s Health Initiative. We analyzed ∼7 million single nucleotide polymorphisms (SNPs). Linear regression models were used to assess associations between each SNP and serum concentrations (log transformed, continuous) of lycopene; we adjusted for age, body mass index, and population substructure. Models were run separately by ethnicity, and results were combined in a transethnic fixed-effects meta-analysis.Results: In the meta-analysis, the scavenger receptor class B, member 1 (SCARB1) gene, which encodes for a cholesterol membrane transporter, was significantly associated with lycopene concentrations (rs1672879; P < 2.68 × 10−9). Each additional G allele resulted in a 12% decrease in lycopene concentrations for African Americans, 20% decrease for Hispanic Americans, and 9% decrease for European Americans. In addition, 2 regions were significantly associated with serum lycopene concentrations in African Americans: the slit homolog 3 gene (SLIT3), which serves as a molecular guidance cue in cellular migration, and the dehydrogenase/reductase (SDR family) member 2 (DHRS2) gene, which codes for an oxidoreductase that mitigates the breakdown of steroids.Conclusions: We found 3 novel loci associated with serum lycopene concentrations, 2 of which were specific to African Americans. Future functional studies looking at these specific genes may provide insight into the metabolism and underlying function of lycopene in humans, which may further elucidate lycopene’s influence on disease risk and health. This trial was registered at clinicaltrials.gov as NCT00000611.

Genetic Variants Reflecting Higher Vitamin E Status in Men Are Associated with Reduced Risk of Prostate Cancer

Vitamin E (α-tocopherol) plays a key role in the regulation of cell growth and differentiation and has been studied as a potential chemopreventive agent for prostate cancer. The association of serum vitamin E concentrations with cancer risk may be modified by genetic variations in vitamin E–related genes. We examined whether variants in vitamin E–related genes were associated with risk of prostate cancer in a nested case-control study using 483 prostate cancer cases and 542 matched controls of European ancestry from a large U.S. multicenter trial that had available measurements of serum vitamin E concentrations and genotyping of 3 genome-wide association study meta-analysis–identified single-nucleotide polymorphisms (SNPs) associated with circulating vitamin E. ORs and 95% CIs were calculated using unconditional logistic regression adjusted for age, family history of prostate cancer, and serum total cholesterol. Findings suggest lower prostate cancer risk for men whose genotypes reflect higher vitamin E (i.e., α-tocopherol) status. An SNP (rs964184) near budding-site selection protein 13 (yeast) (BUD13), zinc finger protein 259 (ZNF259), and apolipoprotein A5 (APOA5) on 11q23.3 was significantly associated with prostate cancer risk (per-allele OR = 0.75; 95% CI: 0.58, 0.98; P-trend = 0.03). The association between rs964184 and prostate cancer risk was stronger among homozygous carriers of the minor allele (OR = 0.27; 95% CI: 0.09, 0.83). Another variant, rs11057830 in scavenger receptor class-B member 1 (SCARB1) on 12p24.31, approached statistical significance (OR = 0.32; 95% CI: 0.10, 1.01, P = 0.05; 2 minor allele copies). This study suggests that polymorphisms near BUD13/ZNF259/APOA5, involved in vitamin E transport and metabolism, may be associated with lower risk of prostate cancer. This trial was registered at clinicaltrials.gov> as NCT00002540.