Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) have recently been identified to be closely related to the occurrence and development of atherosclerosis (AS). A growing body of evidence has suggested Chinese medicine takes unique advantages in preventing and treating AS. In this review, the related research progress of AS and LOX-1 has been summarized. And the anti-AS effects of 10 active components of herbal medicine through LOX-1 regulation have been further reviewed. As a potential biomarker and target for intervention in AS, LOX-1 targeted therapy might provide a promising and novel approach to atherosclerotic prevention and treatment.
Humans ; Atherosclerosis ; Scavenger Receptors, Class E/physiology* ; Biomarkers ; Plant Extracts ; Lipoproteins, LDL

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

OBJECTIVETo 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.

METHODSThe 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.

RESULTSThe 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.

CONCLUSIONThis 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

BACKGROUNDLipid abnormalities are often complicated by renal dysfunction. 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) are the first-line choice for lowering cholesterol levels. The present study was designed to investigate whether statins could prevent and invert the development of renal injury in cholesterol-fed rabbits and to find the possible mechanism of their effects by detecting gene and protein expression of lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) in the renal artery.

METHODSTwenty-four male New Zealand white rabbits were divided into three groups: (1) control group, regular granules chow; (2) HC-diet group, granules chow with 1% cholesterol and 5% lard oil; and (3) fluvastatin group, 1% cholesterol and 5% lard oil diet plus fluvastatin [10 mg.kg(-1).d(-1)]. After 16 weeks, serum total cholesterol (TC), low-density lipoprotein (LDL) and creatinine (Cr) levels were measured. Renal hemodynamics and function, mainly including glomerular filtration rate (GFR) in vivo were quantified using (99m)Tc-DTPA single photon emission computed tomograph ((99m)Tc-DTPA SPECT). The thickness of the renal artery intima was quantitated in HE-stained segments by histomorphometry. Gene expression of LOX-1 in the renal artery was examined by semi-quantitative RT-PCR and its protein expression was evaluated by immunohistochemistry.

RESULTSHigh cholesterol diet induced hypercholesterolemia (HC) complicated by renal dysfunction with increased levels of serum lipid and Cr, decreased GFR and delayed excretion and extensively thickened renal arterial intima in the HC-diet group. Rabbits in the control group showed a minimal LOX-1 expression (mRNA and protein) in the endothelium and neointima of the renal artery. Intimal proliferation of the renal artery in the HC-diet group was associated with a marked increase of LOX-1 expression (protein and mRNA). Treatment with fluvastatin improved renal function, attenuated intimal proliferation of the renal artery and markedly decreased the enhanced LOX-1 expression in the endothelium and neointima of the renal artery in rabbits.

CONCLUSIONSFluvastatin treatment could prevent the development of renal injury in patients with HC and early atherosclerosis (AS). This beneficial effect might be mediated by its pleiotropic effects including a decrease in total cholesterol exposure level and prevention of LOX-1 expression in atherosclerotic arteries.

Animals ; Cholesterol ; blood ; Creatinine ; blood ; Fatty Acids, Monounsaturated ; pharmacology ; Hydroxymethylglutaryl-CoA Reductase Inhibitors ; pharmacology ; Hypercholesterolemia ; drug therapy ; metabolism ; pathology ; Immunohistochemistry ; Indoles ; pharmacology ; Kidney ; drug effects ; pathology ; Male ; RNA, Messenger ; analysis ; Rabbits ; Receptors, LDL ; analysis ; genetics ; Receptors, Oxidized LDL ; Scavenger Receptors, Class E ; Tomography, Emission-Computed, Single-Photon

OBJECTIVETo investigate the effects of oxidized low-density lipoprotein receptor 1 (LOX-1) on secretion of adhesive molecules mediated by ox-LDL in human umbilical endothelial cells (HUVECs).

METHODSHUVECs with different concentration of ox-LDL (0, 10, 20, 50, 100 microg/ml) were incubated for 24 h, or HUVECs were pretreated with 250 microg/ml poly (I) or 250 microg/ml carrageenan for 2 h and then incubated with 50 microg/ml ox-LDL for another 24 h. Expression of LOX-1 was determined by realtime RT-PCR and Western blot. mRNA and protein of ICAM-1, VCAM-1 and E-selectin were examined by RT-PCR and Western blot respectively.

RESULTSIncubation of HUVECs with ox-LDL (10-100 microg/ml) enhanced the expressions of LOX-1, ICAM-1 and E-selectin in a concentration-dependent manner (P < 0.01). On the contrary, ox-LDL did not affect the expression of VCAM-1 by HUVECs. The expression of LOX-1, ICAM-1 and E-selectin induced by ox-LDL were reduced in HUVECs pretreated with 250 microg/ml poly (I) or 250 microg/ml carrageenan for 2 h and then incubated with 50 microg/ml ox-LDL for 24 h. This showed that both poly (I) and carrageenan obviously decreased the expression of LOX-1, ICAM-1 and E-selectin induced by ox-LDL.

CONCLUSIONox-LDL may upregulate the expression of LOX-1, ICAM-1 and E-selectin, and LOX-1 blocker may partly inhibit this upregulation. The results suggest that the expression of inflammatory molecules induced by ox-LDL in HUVECs is mediated by LOX-1.

Cell Adhesion ; Cell Adhesion Molecules ; Cells, Cultured ; E-Selectin ; metabolism ; Endothelial Cells ; metabolism ; Endothelium, Vascular ; metabolism ; Humans ; Intercellular Adhesion Molecule-1 ; metabolism ; Lipoproteins, LDL ; biosynthesis ; RNA, Messenger ; metabolism ; Receptors, Oxidized LDL ; metabolism ; Scavenger Receptors, Class E ; metabolism ; Umbilical Veins ; cytology ; Vascular Cell Adhesion Molecule-1 ; metabolism

OBJECTIVETo study on the regulatory mechanism of lipid metabolism disorders in the blood fat of hyperlipemia rat model with Olive Antihyperlipidemia capsule, and do systematic observation on the functions of this medicine on low And high density lipoprotein receptor in rat liver gene expression, and then to clarify the mechanism of action of this medicine on treating hyperlipemia.

METHODTo select SD rat as investigated subject. The hyperlipemia rat models were made with feeding high-fat forage and were randomly divided into six groups based on the total cholesterol level at the ratsfasting for 12 hours: group A, B, C, D, E and group F. The samples in the research were collected and analyzed the changes of LDLR/SR-B1 gene expression in rat's liver by RT-PCR.

RESULTOlive Antihyperlipidemia capsule can markedly enhance LDLR/SR-B1 gene expression in rat's liver and finally accomplish the purpose of reducing blood fat. The experiment shows this medicine has the remarkable effect on hyperlipidemia and proved the theoretical system of treating hyperlipemia for curing the liver is correct.

CONCLUSIONOlive Antihyperlipidemia capsule has an applicable value on preventing the cause, enhance LDLR/SR-B1 gene expression in rat's liver and finally accomplish the purpose of reducing blood fat and development of hyperlipemia and its complications.

Animals ; Capsules ; Drugs, Chinese Herbal ; isolation & purification ; pharmacology ; Gene Expression Regulation ; drug effects ; Hyperlipidemias ; genetics ; pathology ; prevention & control ; Hypolipidemic Agents ; isolation & purification ; pharmacology ; Lipoproteins, HDL ; genetics ; Liver ; metabolism ; Male ; Olea ; chemistry ; Plants, Medicinal ; chemistry ; RNA, Messenger ; biosynthesis ; genetics ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Receptors, LDL ; genetics ; Receptors, Lipoprotein ; genetics ; Scavenger Receptors, Class B ; genetics

AIMTo develop a fluorescence polarization-based high throughput screening and identify ligands for human Lectin-like oxidized low-density lipoprotein receptor-1 (hLOX-1).

METHODSSequential ultracentrifugation at 4 degrees C from normolipidemic fasting volunteers to obtain low density lipoprotein (LDL), which was modified by CuSO4 (5 micromol x L(-1)) at 37 degrees C for 24 h. The assay was based on the interaction between receptor and ligand, and hLOX-1 was labeled by FITC and bound to its specific ligand, oxLDL. Different reaction time and DMSO concentration were optimized to determine the stability and tolerance of fluorescence polarization (FP) assay. 3 200 compounds were screened in black 384-well microplate by FP-based competitive displacement assay, at excitation filter of 485 nm and emission filter of 530 nm. Z' was used to assess the assay quality.

RESULTSThe FP-based HTS was formatted in a 384-well microplate with a Z' factor of 0. 75, and three active compounds for hLOX-1 were identified with IC50 below 40 micromol x L(-1) from total 3 200 compounds.

CONCLUSIONThe results indicated that the fluorescence polarization assay is stable, sensitive, reproducible and well suited for high throughput screening efforts.

Binding, Competitive ; Drug Evaluation, Preclinical ; methods ; Fluorescence Polarization ; methods ; Humans ; Ligands ; Lipoproteins, LDL ; metabolism ; Scavenger Receptors, Class E ; metabolism

OBJECTIVETo determine the genomic structure of low density lipoprotein receptor related protein 5 (LRP5) gene.

METHODScDNA sequence encoding LRP5 was used to screen genomic clones containing LRP5 gene by computer hybridization approach. By comparing the cDNA sequence of LRP5 with the genomic sequences, the genomic structure of LRP5 was determined, and then it was conformed by amplifying and sequencing the sequences of exons and splicing junction.

RESULTSThe genomic sequence of LRP5 gene was 131.6 kb in length, containing 23 exons and 22 introns. Three single nucleotide polymorphisms were detected within the coding sequences of LRP5 gene, namely A459G in exon 2, C2220T in exon 10 and G4416C in exon 21. Four polymorphic markers, D11S1917, D11S4087, D11S1337 and D11S4178, located in the 5' flank sequence, introns 1, 4, and 13 of the LRP5 gene, respectively.

CONCLUSIONThe characterization of genomic structure of LRP5 gene allows the investigators to detect disease-causing mutation within the gene and further study the function of LRP5 gene.

Base Sequence ; DNA ; chemistry ; genetics ; Exons ; Genes ; genetics ; Humans ; Introns ; LDL-Receptor Related Proteins ; Low Density Lipoprotein Receptor-Related Protein-5 ; Polymorphism, Single Nucleotide ; Receptors, LDL ; genetics ; Sequence Analysis, DNA

OBJECTIVETo develop a new high-throughput screening model for human high-density lipoprotein (HDL) receptor (CD36 and LIMPII analogous-1, CLA-1) agonists using CLA-1-expressing insect cells.

METHODSWith the total RNA of human hepatoma cells BEL-7402 as template, the complementary DNA (cDNA) of CLA-1 was amplified by reverse transcription-polymerase chain reaction (RT-PCR). Bac-to-Bac baculovirus expression system was used to express CLA-1 in insect cells. CLA-1 cDNA was cloned downstream of polyhedrin promoter of Autographa californica nuclear polyhedrosis virus (AcNPV) into donor vector pFastBac1 and recombinant pFastBac1-CLA-1 was transformed into E. coli DH10Bac to transpose CLA-1 cDNA to bacmid DNA. Recombinant bacmid-CLA-1 was transfected into Spodoptera frugiperda Sf9 insect cells to produce recombinant baculovirus particles. Recombinant CLA-1 was expressed on the membrane of Sf9 cells infected with the recombinant baculoviruses. A series of parameters of DiI-lipoprotein binding assays of CLA-1-expressing Sf9 cells in 96-well plates were optimized.

RESULTSWestern blot analysis and DiI-lipoprotein binding assays confirmed that CLA-1 expressed in insect cells had similar immunoreactivity and ligand binding activity as its native counterpart. A reliable and sensitive in vitro cell-based assay was established to assess the activity of CLA-1 and used to screen agonists from different sample libraries.

CONCLUSIONHuman HDL receptor CLA-1 was successfully expressed in Sf9 insect cells and a novel high-throughput screening model for CLA-1 agonists was developed. Utilization of this model allows us to identify potent and selective CLA-1 agonists which might possibly be used as therapeutics for atherosclerosis.

Animals ; Baculoviridae ; genetics ; metabolism ; Biological Assay ; Carbocyanines ; metabolism ; Cell Line, Tumor ; Cholesterol, HDL ; metabolism ; DNA, Complementary ; genetics ; metabolism ; Fluorescent Dyes ; metabolism ; Gene Expression ; Humans ; Lipoproteins, HDL ; agonists ; genetics ; metabolism ; Lipoproteins, LDL ; metabolism ; Receptors, Lipoprotein ; agonists ; genetics ; metabolism ; Recombinant Proteins ; genetics ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Scavenger Receptors, Class B ; agonists ; genetics ; metabolism ; Spodoptera ; genetics ; metabolism

OBJECTIVETo study the changes of lectin-like oxidized low density lipoprotein receptor-1 (LOX-1) expression in the autologous vein grafts and vein graft atherosclerotic lesions.

METHODSThirty New Zealand white rabbits were randomly assigned to normal control group (rabbits fed with normal diet, n = 10), vein graft group (autologous external jugular vein grafting to common carotid artery and fed with normal diet, n = 10) or vein graft plus high-lipid diet group (autologous vein graft and fed with high-lipid diet, n = 10) for 12 weeks. LOX-1 expressions in the grafts were examined by immunohistochemistry and semi-quantitative reverse transcription-PCR. The relationships between serum total cholesterol level, intimal thickness and LOX-1 expression were also investigated.

RESULTSLOX-1 expression was low in the endothelium of external jugular veins in the normal control group and significantly increased in the endothelium and neointima of vein grafts in the vein graft group (0.31 +/- 0.14 vs. 0.09 +/- 0.04, P < 0.01) and which was further increased in the endothelium and atherosclerotic lesions in the vein graft plus high-lipid diet group (0.93 +/- 0.34 vs. 0.31 +/- 0.14, P < 0.01). LOX-1 expression in the atherosclerotic lesions was located both in endothelial cells and foam cells and the expression was most prominent in endothelial cells. LOX-1 expression and intimal thickness were positively related to serum total cholesterol level (P = 0.00 and 0.02) and the partial correlation coefficient was 0.78 and 0.42, respectively.

CONCLUSIONSLOX-1 expression is increased in endothelium and neointima of autologous vein grafts of rabbits. Hypercholesterolemia upregulates LOX-1 expression in vein graft atherosclerosis. Thus, LOX-1 might play an important role in the pathogenesis of vein graft atherosclerosis.

Animals ; Atherosclerosis ; metabolism ; pathology ; Disease Models, Animal ; Graft Occlusion, Vascular ; metabolism ; pathology ; Lipoproteins, LDL ; blood ; Male ; Rabbits ; Scavenger Receptors, Class E ; metabolism ; Transplantation, Autologous ; Veins ; transplantation