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

OBJECTIVETo investigate the effect of FXR on scavenger receptor class B type I (SR-BI) expression.

METHODSHuman 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.

RESULTSThe 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.

CONCLUSIONFXR 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

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 review the recent research progress in lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) including its protein, ligands, expression and pathophysiological significance. Data sources Information included in this article was identified by searching of PUBMED (1997 - 2006) online resources using the key term LOX-1.

STUDY SELECTIONMainly original milestone articles and critical reviews written by major pioneer investigators of the field were selected.

RESULTSThe key issues related to the LOX-1 protein as well as ligands for LOX-1. Factors regulating the expression of LOX-1 were summarized. The pathophysiological functions of LOX-1 in several diseases were discussed.

CONCLUSIONSIdentification of LOX-1 and a definition of its biological role in pathophysiologic states provide deeper insight into the pathogenesis of some cardiovascular diseases especially in atherosclerosis and provide a potential selective therapeutic approach. LOX-1 is unlocking and drugs targeting LOX-1 might be a promising direction to explore.

Animals ; Arthritis, Rheumatoid ; etiology ; Atherosclerosis ; etiology ; Humans ; Ligands ; Myocardial Infarction ; etiology ; Osteoarthritis ; etiology ; Scavenger Receptors, Class E ; chemistry ; genetics ; physiology

The aim of the study is to identify the effects and underlying mechanisms of visfatin on inflammation and necroptosis in vascular endothelial cells. Human umbilical vein endothelial cells (HUVECs) were stimulated with visfatin or pretreated with Polyinosinic acid (LOX-1 inhibitor). By using the Western blot, RT-PCR, immunocytochemistry, enzyme-linked immunosorbent assay (ELISA), MTT and flow cytometry technique, the occurrence of inflammation and necroptosis in HUVECs were evaluated. Our results showed that 100 ng/mL visfatin significantly increased the mRNA and protein expression of monocyte chemotactic protein 1 (MCP-1) and LOX-1 after 24 hours' treatment in HUVECs. However, pretreatment with Polyinosinic acid could significantly reduce the expression of MCP-1 compared with visfatin group. Additionally, 100 ng/mL visfatin could induce the production of necrotic features and increase the mRNA expression of BMF (one of the markers of necroptosis), while pretreating with Polyinosinic acid markedly downregulated the mRNA expression of BMF gene and promoted the cell proliferation. These results indicate that visfatin might induce inflammation and necroptosis via LOX-1 in HUVECs, suggesting that visfatin plays a central role in the development of atherosclerosis.
Cells, Cultured ; Human Umbilical Vein Endothelial Cells ; Humans ; Inflammation/chemically induced* ; Necroptosis ; Nicotinamide Phosphoribosyltransferase ; Scavenger Receptors, Class E/genetics*

OBJECTIVETo explore the regulational effect of oxidized low-density lipoprotein (Ox-LDL) on expression of type A scavenger receptor (SR-A) in human mesangial cells (HMC).

METHODSHMC line (HMCL) with high expression of SR-A (HMCL-SRA) was established after stable transfection of expressive vector with cDNA encoding SR-A. Uptake of Ox-LDL by HMCL was evaluated using Oil Red "O" staining. SR-A mRNA expression was examined using reverse transcription-polymerase chain reaction (RT-PCR).

RESULTSMore uptake of Ox-LDL was observed in the HMCL-SRA than that in the untransfected HMCL. Ox-LDL could induce SR-A mRNA expression in HMC in a dose-dependent manner, and reached a peak level after 24 h of stimulation. After 24 h of stimulation with Ox-LDL at the dose of 10, 50 and 100 micrograms/ml, SR-A mRNA expression was up-regulated to 1.35, 1.83 and 2.30-fold of controls, respectively. However, LDL had no effect on the expression of SR-A.

CONCLUSIONSIt suggests that SR-A be a major binding receptor to uptake Ox-LDL in HMC. Ox-LDL may promote the progression of chronic renal diseases through up-regulation of SR-A.

Cells, Cultured ; DNA, Complementary ; Glomerular Mesangium ; cytology ; metabolism ; Humans ; Lipoproteins, LDL ; pharmacology ; RNA, Messenger ; biosynthesis ; genetics ; Receptors, Immunologic ; biosynthesis ; genetics ; Receptors, Scavenger ; Reverse Transcriptase Polymerase Chain Reaction ; Scavenger Receptors, Class A ; Transfection ; Up-Regulation

OBJECTIVETo explore action mechanism of electroacupuncture for coronary atherosclerotic heart disease (CHD) in order to provide experimental support for clinical acupoint selection.

METHODSAmong sixty clean-grade healthy male Wistar rats, twenty-four cases were randomly selected as a normal control group and an electroacupuncture (EA) preconditioning group, 12 cases in each one. Then rats in the EA preconditioning group and the rest 36 rats were fed with high fat diet for 12 weeks to duplicate the CHD model. When the models were successfully established, the rats were randomly divided into a model control group, an EA group and a medication group, 12 cases in each one. EA was applied with Hwa-to SDZ-IV apparatus in the EA preconditioning group at "Neiguan" (PC 6) and "Xinshu" (BL 15), 1 mA in current intensity, 2 Hz in frequency, 30 min per times, once every other day for 14 weeks. When model was established, the same acupoint and method was used in the EA group for 2 weeks while intragastric administration of atorvastatin mixed suspension, 0.25 mg/kg, once a day, was applied in the medication group for 2 weeks. The content of oxidized low-density lipoprotein (oxLDL) in the serum was tested by double antibody enzyme-linked immunosorbent assay (ELISA) while content of lectin-like oxidized low density lipoprotein receptor-1 (LOX-1) in coronary arterial tissue was test by western blot method. Expression of LOX-1 mRNA was tested by fluorogenic quantitative polymerase chain reaction (PCR).

RESULTSAfter model was duplicated successfully, the content of oxLDL in the serum and the expression of LOX-1 and its mRNA in coronary arterial tissue in the model control group were increased significantly compared with those in the normal control group (all P < 0.01). Compared with the model control group, the content of oxLDL in the serum and the expression of LOX-1 and its mRNA in coronary arterial tissue in the EA preconditioning group, EA group and medication group were significantly reduced (all P < 0.01).

CONCLUSIONThe electroacupuncture at "Neiguan" (PC 6) and "Xinshu" (BL 15) could effectively reduce the content of oxLDL in the serum and expression of LOX-1 and its mRAN in coronary arterial tissue in CHD rats. The oxidative modificatory low-density lipoprotein and its specific receptor system could be one of the ways to prevention and treatment of acupuncture for CHD.

Animals ; Coronary Disease ; genetics ; metabolism ; therapy ; Disease Models, Animal ; Electroacupuncture ; Humans ; Lipoproteins, LDL ; genetics ; metabolism ; Male ; Rats ; Rats, Wistar ; Scavenger Receptors, Class E ; genetics ; metabolism

OBJECTIVETo assess the value of serum soluble lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) levels and LOX-1 mRNA expression in peripheral blood mononuclear cells in early diagnosis of acute coronary syndrome (ACS).

METHODSEnzyme-linked immunosorbent assay was used to detect the levels of plasma ox-LDL and LOX-1 in 95 patients with ACS, 60 with stable angina pectoris (SAP) and 40 normal control subjects. The expression of LOX-1 mRNA in peripheral blood mononuclear cells was detected by RT-PCR in the 3 groups.

RESULTSThe levels of ox-LDL, LOX-1 and LOX-1 mRNA in the peripheral blood mononuclear cells were significantly higher in ACS patients than in SAP patients and normal control subjects (P<0.05). In ACS group, the level of plasma ox-LDL was significantly correlated to serum LOX-1 and LOX-1 mRNA expression in peripheral mononuclear cells.

CONCLUSIONThe level of plasma soluble LOX-1 and LOX-1 mRNA in peripheral mononuclear cells are significantly increased in ACS, and when combined, they provide a useful means for detecting ACS in the prophase.

Acute Coronary Syndrome ; blood ; diagnosis ; Aged ; Early Diagnosis ; Female ; Humans ; Leukocytes, Mononuclear ; metabolism ; Male ; Middle Aged ; RNA, Messenger ; genetics ; Scavenger Receptors, Class E ; blood

The present study was to investigate whether endoplasmic reticulum stress (ERS) was involved in oxidized low density lipoprotein (ox-LDL)-induced scavenger receptor A1 (SR-A1) upregulation in macrophages. RAW264.7 cells were pretreated with 20 mmol/L of 4-phenylbutyric acid (PBA) for 30 min and then treated with ox-LDL (50 mg/L) for 12 h or stimulated with 2 mg/L tunicamycin (TM) or 2 μmol/L thapsigagin (TG) for 4 h. In addition, RAW264.7 cells were incubated with 0.5, 1 and 2 mg/L TM for 4 h or treated with 2 mg/L TM for 1, 2 and 4 h, respectively. The intracellular total cholesterol (TC) content was measured using a tissue/cell total cholesterol assay kit. The protein and mRNA expressions of SR-A1 and glucose-regulated protein 78 (GRP78) were analyzed by Western blot and real-time PCR, respectively. Dil-ox-LDL uptake was detected using a microplate reader. The results showed that ox-LDL-induced cholesterol accumulation in macrophages was attenuated by PBA, an ERS inhibitor. Ox-LDL caused significant SR-A1 upregulation with concomitant activation of ERS as assessed by upregulation of GRP78, whereas PBA significantly inhibited the ox-LDL-induced SR-A1 upregulation (P < 0.05) and slightly decreased GRP78 expression by 39.3% (P = 0.057). TM, an ERS inducer, upregulated SR-A1 protein expression and ox-LDL uptake in dose- and time-dependent manner, but had no significant effect on SR-A1 mRNA level. However, the TM- or TG-induced SR-A1 upregulation and ox-LDL uptake were significantly mitigated by PBA. These data indicate that ERS plays a critical role in ox-LDL-induced SR-A1 upregulation, which in turn enhances the foam cell formation by uptaking more ox-LDL.
Animals ; Cell Line ; Cholesterol ; metabolism ; Endoplasmic Reticulum Stress ; Heat-Shock Proteins ; metabolism ; Lipoproteins, LDL ; pharmacology ; Macrophages ; drug effects ; metabolism ; Mice ; Scavenger Receptors, Class A ; metabolism ; Up-Regulation

OBJECTIVETo 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.

METHODSRAW264.7 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.

RESULTSCompared 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.

CONCLUSIONRosiglitazone 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