Both hydropathy plot and in vitro translation results predict the topology of SR-BI; the receptor is an integral membrane protein of 509 amino acids, consisting of a short cytoplasmic N-terminus of 9 amino acids followed by a first transmembrane domain of 22 amino acids, the extracellular domain of 408 amino acids, the second transmembrane domain of 22 amino acids, and the cytoplasmic C-terminus of 47 amino acids. The immunoblot of rBBMV in the presence or absence of pAb589 peptide antigen (the C-terminal 22 amino acid residues of SR-BI) confirmed that the bands at apparent molecular weight of 140 and 210 kDa are SR-BI related protein which might be multimeric forms of SR-BI. 125I apo A-I overlay analysis showed that SR-BI can bind to its ligand, apo A-I, only when it is thoroughly matured - glycosylated and dimerized. The antibody which was generated against extracellular domain of SR-BI (pAb230) not only prevented 125I-labeled apo A-I from binding to 140 kDa band but also inhibited the esterified cholesterol uptake of rabbit BBMV with its IC50 value of 40 microgram/ml of IgG. In contrast, the antibody generated against the C-terminal domain of SR-BI (pAb589) did not show any effect either on cholesterol uptake of rabbit BBMV or 125I-labeled apo A-I binding to 140 kDa band. Overall results show that the ligand binding site of SR-BI in rabbit BBMV is located in extracellular domain, and SR-BI is only functional when it is part of dimeric forms which rationalize the previously found cooperative nature of the binding interaction and maybe a fundamental finding towards the so far poorly understood mechanism of SR-BI function.
Amino Acid Sequence ; Animals ; Antigens, CD36/*metabolism ; Apolipoprotein A-I/metabolism ; Binding Sites/physiology ; Blotting, Western ; Caco-2 Cells ; Cholesterol Esters/metabolism ; Humans ; Intestinal Mucosa/metabolism ; Intestine, Small/*metabolism/ultrastructure ; Iodine Radioisotopes ; Membrane Proteins/*metabolism ; Microvilli/metabolism ; Molecular Sequence Data ; Rabbits ; *Receptors, Immunologic ; Receptors, Lipoprotein/*metabolism ; Receptors, Scavenger ; Scavenger Receptors, Class B ; Surface Properties

<b>OBJECTIVEb>To establish a new drug screening model based on transcriptional regulation of human high density lipoprotein (HDL) receptor gene CD36 and LIMPII analogous-1 (CLA-1) for discovering up-regulator of this receptor.

<b>METHODSb>The upstream regulatory sequence of CLA-1 was obtained by polymerase chain reaction. A recombinant reporter plasmid pGL3-CLAP was constructed by inserting the regulatory sequence upstream of luciferase gene of pGL3-Basic. Human hepatoma cell line BEL-7402 was transfected with pGL3-CLAP. Samples were detected by testing luciferase activity of transfected BEL-7402 cells in microtiter wells.

<b>RESULTSb>The drug screening model was established and optimized. Significant difference was present between pGL3-CLAP and pGL3-Basic transfected BEL-7402 cells (P< 0.001), and coefficient of variation was less than 10%. After primary and secondary screening, 1 compounds and 3 fermentation extracts had up-regulating activities.

<b>CONCLUSIONb>This new drug screening model may be efficiently used to screen up-regulators of human HDL receptor expression, which might become lead compounds for new anti-atherosclerosis drugs.

CD36 Antigens ; Cholesterol Esters ; metabolism ; Drug Evaluation, Preclinical ; methods ; Gene Expression Regulation ; drug effects ; Humans ; Hypolipidemic Agents ; chemical synthesis ; pharmacology ; Lipoproteins, HDL ; genetics ; metabolism ; RNA, Messenger ; metabolism ; RNA-Binding Proteins ; Receptors, Immunologic ; genetics ; Receptors, Lipoprotein ; genetics ; Receptors, Scavenger ; Scavenger Receptors, Class B ; Transcription, Genetic ; drug effects ; Up-Regulation

<b>OBJECTIVEb>To investigate the effect of FXR on scavenger receptor class B type I (SR-BI) expression.

<b>METHODSb>Human vascular endothelium Eahy926 cells were treated with FXR agonist androsterone, and the specific target gene of FXR SHP mRNA was detected by RT-PCR. SR-BI mRNA and protein were determined using RT-PCR, real-time PCR and Western blotting.

<b>RESULTSb>The level of SHP mRNA in Eahy926 cells increased after androsterone treatment at different concentrations for 24 h, demonstrating FXR activation in the cells. RT-PCR, real-time PCR and Western blotting detected increased SR-BI expression at both mRNA and protein levels after FXR activation.

<b>CONCLUSIONb>FXR increases the expression of SR-BI in human vascular endothelium cells.

Androsterone ; pharmacology ; Cell Line ; Endothelial Cells ; drug effects ; metabolism ; Humans ; Receptors, Cytoplasmic and Nuclear ; agonists ; metabolism ; Scavenger Receptors, Class B ; metabolism

<b>OBJECTIVEb>To observe the effect of rosiglitazone on the content of cholesterol and expressions of Acy-coenzyme A: cholesterol acyltransferase 1 (ACAT-1) and scavenger receptor class B type I (SR-BI) in RAW264.7 macrophage-derived foam cells and explore the anti-atherosclerotic mechanism of rosiglitazone.

<b>METHODSb>RAW264.7 macrophages were incubated with oxidized low-density lipoproteins (ox-LDL) or with both ox-LDL and rosiglitazone (5, 10, or 20 µmol/L). Oil red O staining was used to observe the formation of foam cells, and cholesterol oxidase was used to determine the content of cellular cholesterol contents. Western blotting was used observe the expressions of ACAT-1 and SR-BI in RAW264.7 foam cells.

<b>RESULTSb>Compared with the control cells, RAW264.7 macrophage-derived foam cells showed significantly increased contents of total cholesterol and free cholesterol (P<0.01) and ACAT-1 expressions (P<0.05) with mildly increased SR-BI expression (P>0.05). Rosiglitazone treatments significantly lowered the contents of total cholesterol and free cholesterol (P<0.05), decreased the expression of ACAT-1 (P<0.05), and increased SR-BI expression (P<0.05) in the foam cells in a dose-dependent manner.

<b>CONCLUSIONb>Rosiglitazone can decrease the contents of total and free cholesterol, down-regulate ACAT-1 expression and up-regulate SR-BI expression in the foam cells produce the anti-atherosclerotic effect.

Acetyl-CoA C-Acetyltransferase ; metabolism ; Cell Line ; Cholesterol ; metabolism ; Foam Cells ; cytology ; drug effects ; metabolism ; Humans ; Scavenger Receptors, Class B ; metabolism ; Thiazolidinediones ; pharmacology

The present paper is to research the expression level of the mRNA of scavenger receptor class B type 1-receptor of high-density lipoprotein in endothelial cells after being treated by different shear stress. The second to fourth generations of the cultured human umbilical vein endothelial cells (HUVECs) were used in the experiment. The cells were divided into two groups. The first group was the control group which was not dealt with shear stress; the second group was the experimental group which concluded low shear stress group (4.2 dyne/cm2), moderate shear stress group (8.4 dyne/cm2) and high shear stress group (15 dyne/cm2). The load time was 1h, 2h, 4h and 8h, respectively. Harvesting the cells and extracting total RNA after being treated by different shear stresses, the expression level of the SR-B1 mRNA was detected by semi-quantitative RT-PCR technic. It was found that the expression of SR-B1 mRNA became weaker and weaker compared to the control group when it was stimulated continuously by the low shear stress, the lowest expression of SR-B1 mRNA appeared at 8h. In the moderate shear stress group, the expression of SR-B1 mRNA increased obviously. Compared to the control group, there was significant difference after being treated with 2h. In the high shear stress group, the expression of SR-B1 mRNA increased immediately when it was stimulated by the shear stress. And the expression of SR-B1 mRNA arrived peak value at 4h. Compared to the control group, there was significant difference after being treated for 1h. It was concluded that the harmful mechanism of the low shear stress is that it can increase the incidence of the atherosclerosis by reducing the reverse cholesterol transport and endothelial protection through decreasing the expression of the SR-B1. Otherwise, the high shear stress prevent the genesis of atherosclerosis by the contrary mechanism.
Atherosclerosis ; etiology ; Cells, Cultured ; Human Umbilical Vein Endothelial Cells ; cytology ; metabolism ; Humans ; RNA, Messenger ; genetics ; metabolism ; Scavenger Receptors, Class B ; genetics ; metabolism ; Stress, Mechanical

To explore the anti-atherosclerotic mechanism of estrogen and especially observe the effect of estradiol on the content of cholesterol in J774a.1 mouse mononuclear/macrophage-derived foam cells which were incubated with oxidized low-density lipoproteins (ox-LDL). J774a.1 mouse mononuclear/macrophages were incubated with ox-LDL or with both ox-LDL and estradiol (1, 0.1 or 0.01 micromol x L(-1)). Oil red O staining was used to observe the formation of foam cells, and cholesterol oxidase fluorometric was used to determine the content of cellular cholesterol content. Western blotting and RTFQ-PCR were used to observe the expressions of scavenger receptor class B type I (SR-B I ) in J774a.1 foam cells. Compared with the control cells, J774a.1 mouse mononuclear/macrophage-derived foam cells showed significantly increased contents of total cholesterol and cholesterol ester (P < 0.001) and decreased SR-B I mRNA expression (P < 0.01). Estradiol treatment significantly lowered the contents of total cholesterol and cholesterol ester (P < 0.05), and increased SR-B I protein and mRNA expression (P < 0.01) in the foam cells in a dose-dependent manner. Estradiol can inhibit the formation of mononuclear/macrophage-derived foam cells by decreasing the contents of total cholesterol and cholesterol ester and up-regulating the expression of SR-B I in the foam cells.
Animals ; Cell Line ; Cholesterol ; metabolism ; Cholesterol Esters ; metabolism ; Estradiol ; pharmacology ; Foam Cells ; cytology ; metabolism ; Lipoproteins, LDL ; metabolism ; Macrophages ; drug effects ; metabolism ; Mice ; Scavenger Receptors, Class B ; metabolism

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.
Male ; Humans ; Female ; Methylation ; Case-Control Studies ; China ; Coronary Artery Disease/genetics* ; Promoter Regions, Genetic ; DNA Methylation ; Scavenger Receptors, Class B/genetics*

OBJECTIVE: To explore whether oxidized low-density lipoprotein (ox-LDL) can stimulate the cholesterol efflux in fully differentiated 3T3-L1 cells and the possible mechanism. METHODS: Fully differentiated 3T3-L1 cells were incubated in the medium containing various concentrations of ox-LDL ( 0 to 50 microg/mL) for 8 or 24 hours. 22(R)-Hydroxycholesterol (10 micromol/L) was exposed to preconditioned adipocytes with 25 microg/mL ox-LDL for 24 hours. Reverse transcription polymerase chain reaction (RT-PCR) was used to evaluate ATP binding cassette transporter A1 (ABCA1), scavenger receptor class B type I (SR-BI), and liver X receptor alpha (LXRalpha) mRNA expression. Cholesterol efflux mediated by apolipoprotein A-I (apoA-I) was determined using liquid scintillator. RESULTS: Low levels (12.5-25 microg/mL) of ox-LDL could increase cholesterol efflux via the enhancement of ABCA1 pathway and SR-BI expression, whereas the higher concentration (50 microg/mL) could not. In adipocytes preincubated with 25 microg/mL ox-LDL for 24 hours, 22(R)-hydroxycholesterol could increase ABCA1 and LXRalpha mRNA and apoA-I-mediated cholesterol efflux, but had no effect on the SR-BI mRNA expression. CONCLUSION Low levels of ox-LDL may enhance the LXRalpha-ABCA1-apoA-I pathway in adipocytes, up-regulate SR-BI mRNA expression, and then increase the cholesterol efflux. This new effect of ox-LDL will not only make contribution to cholesterol homeostasis in adipocytes, but also be potentially atheroprotective.
3T3-L1 Cells ; ATP Binding Cassette Transporter 1 ; metabolism ; Adipocytes ; drug effects ; metabolism ; Animals ; Cholesterol ; metabolism ; Lipid Metabolism ; Lipoproteins, LDL ; pharmacology ; Liver X Receptors ; Mice ; Orphan Nuclear Receptors ; metabolism ; Scavenger Receptors, Class B ; metabolism

Atopic dermatitis (AD) is an inflammatory skin disorder that is both uncomfortable and distressing to patients, and its prevalence has been steadily increasing. It is obvious that the identification of efficient markers of AD in plasma would offer the possibility of effective diagnosis, prevention, and treatment strategies. In this study, a proteomic approach was used to analyze plasma glycoproteins from both children with AD and healthy child donors. Several protein spots showing significant quantitative changes in the AD patients were identified. Through sequential studies, it was confirmed that CD5L and ApoE were significantly up-regulated or down-regulated, respectively, in the plasma from AD patients compared with that from healthy donors. In addition, we suggest that the up-regulated CD5L in AD patients causes eosinophilia by inhibiting apoptosis or promoting the proliferation of eosinophils either in combination with or without IL-5. The glycoproteomic data in this study provides clues to understanding the mechanism of atopic alterations in plasma and suggests AD-related proteins can be used as candidate markers for AD.
Apolipoproteins E/*blood ; Biological Markers/blood ; Cell Line ; Cell Proliferation ; Child ; Dermatitis, Atopic/*metabolism ; Eosinophilia/metabolism ; Eosinophils/physiology ; Female ; Glycoproteins/*blood ; Humans ; Interleukin-5/metabolism ; Male ; Proteomics ; Scavenger Receptors, Class B/*blood

Hepatitis C virus (HCV) is a positive sense, single-stranded RNA virus in the Flaviviridae family. It causes acute hepatitis with a high propensity for chronic infection. Chronic HCV infection can progress to severe liver disease including cirrhosis and hepatocellular carcinoma. In the last decade, our basic understanding of HCV virology and life cycle has advanced greatly with the development of HCV cell culture and replication systems. Our ability to treat HCV infection has also been improved with the combined use of interferon, ribavirin and small molecule inhibitors of the virally encoded NS3/4A protease, although better therapeutic options are needed with greater antiviral efficacy and less toxicity. In this article, we review various aspects of HCV life cycle including viral attachment, entry, fusion, viral RNA translation, posttranslational processing, HCV replication, viral assembly and release. Each of these steps provides potential targets for novel antiviral therapeutics to cure HCV infection and prevent the adverse consequences of progressive liver disease.
Antigens, CD81/metabolism ; Genome, Viral ; Hepacivirus/genetics/*physiology ; Humans ; RNA, Viral/metabolism ; Scavenger Receptors, Class B/metabolism ; Viral Envelope Proteins/chemistry/metabolism ; Viral Nonstructural Proteins/chemistry/metabolism ; Virus Assembly ; Virus Internalization ; Virus Replication