Failure to replicate an association of SNPs in the oxidized LDL receptor gene (OLR1) with CAD

Association of the ESR1 (rs9340799), OLR1 (rs3736234), LIPC (rs2070895), VDR (rs2228570), and CETP (rs708272) Polymorphisms With Risk of Coronary Artery Disease in Iranian Patients

BACKGROUND

Coronary artery disease (CAD) is a devastating illness and a leading cause of death worldwide, primarily caused by atherosclerosis resulting from a genetic-environmental interaction. This study aimed to investigate the relationship between the ESR1 (rs9340799), OLR1 (rs3736234), LIPC (rs2070895), VDR (rs2228570), and CETP (rs708272) polymorphisms, lipid profile parameters, and CAD risk in a southeast Iranian population.

METHODS

A total of 400 subjects (200 CAD patients with hyperlipidemia and 200 healthy controls) were enrolled in this case-control study. Five selected polymorphisms were genotyped using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique.

RESULTS

For all single nucleotide polymorphisms (SNPs), the population under study was in the Hardy-Weinberg equilibrium. The T-risk allele frequency of rs2228570 was associated with an increased risk of CAD. The TT and CT genotypes of rs2228570 had also been associated with the risk of CAD. Additionally, the TT genotype was associated with higher serum low-density lipoprotein cholesterol (LDL-c) and high-density lipoprotein cholesterol (HDL-c) levels. The GG genotype of the rs3736234 was associated with higher body mass index (BMI) and triglyceride (TG) levels, and the AA genotype of the rs708272 was associated with higher HDL-c levels. Based on these findings, we propose that the VDR (rs2228570) polymorphism was associated with serum HDL-c and LDL-c levels and may serve as potential risk factors for CAD within the Iranian population. Moreover, rs3736234 and rs708272 influence the concentrations of TG and HDL-c, respectively.

CONCLUSION

These findings provided insights into the complex interplay between genetic variations, cardiovascular risk, and lipid metabolism.

Genetic variations in OLR1 gene associated with PCOS and atherosclerotic risk factors

Polycystic ovary syndrome (PCOS) is the most common endocrinopathy in women of reproductive age. The aim of this study was to investigate the association of oxidized low-density lipoprotein receptor 1 (OLR1) gene variations with the susceptibility of PCOS and to examine the relationship between the frequencies of OLR1 gene variations and atherosclerotic risk factors. Genomic DNA was extracted from blood samples collected from 49 patients with PCOS and 43 healthy controls. The variants in the OLR1 gene were identified using next-generation sequencing (NGS). Heterozygous rs11053646 (K167N), rs11611438, rs11611453, and rs35688880 genotype frequencies were significantly higher in the PCOS group than that of control group. Single nucleotide polymorphism (SNP) rs34163097 minor A allele increased the PCOS risk by ∼10-fold (p = 0.03). SNPs rs11053646, rs11611438, rs11611453, rs34163097, and rs35688880 were positively correlated with body mass index (BMI). The logistic regression model (area under the curve: 0.770, p = 0.000) further revealed a combination of 2-h plasma glucose (PG-2 h), dehydroepiandrosterone sulfate (DHEAS), and rs11053646 as predictors of PCOS phenotype. This is the first study reporting the NGS data of OLR1 gene variants which might be associated with the pathogenesis of PCOS and several atherosclerotic risk factors, particularly higher BMI and DHEAS. To fully understand the genetic basis of PCOS and the contribution of OLR1 gene variants to PCOS pathogenesis, additional large-scale studies are warranted.

Lectin-Like OLR1 3'UTR Rs1050286 Gene Polymorphism and Plasma Oxidized-LDL in Coronary Artery Disease and Their Relation to Cardiovascular Risk and Outcomes

BACKGROUND

Oxidized low-density lipoprotein (ox-LDL) has an important role in the genesis of coronary atherosclerosis. Lectin-like ox-LDL receptor 1 (OLR1) contributes to the uptake and internalization of ox-LDL. Genetic polymorphisms have been associated with coronary artery disease (CAD). Here we explore the association of plasma levels of ox-LDL and 3' UTR OLR1 (rs1050286) SNP with CAD risk and in-hospital adverse outcomes.

METHODS

A case-control study enrolled 192 patients with ST-segment elevation myocardial infarction (STEMI), 100 patients with unstable angina, and 100 healthy controls. Baseline, clinical characteristics, and risk scores of the patients were determined. Plasma ox-LDL and other biochemical variables were measured. All subjects are genotyped for OLR1 (rs1050286) by RT-PCR with TaqMan SNP genotyping assay.

RESULTS

Plasma ox-LDL was higher with enhanced sensitivity and specificity in identifying patients with STEMI and was found as a significant independent risk factor for CAD in those two groups. Levels of ox-LDL were increased with increasing poor prognostic factors in STEMI patients that are associated with an increased incidence of some adverse events and in-hospital mortality. Elevated STEMI risk was associated with T allele of OLR1 (rs1050286) (odds ratio of 4.9, 95% CI: 2.6-9.4, p< 0.001). STEMI patients who have T allele exhibited higher risk scores, coronary multivessel narrowing, and elevated incidence of in-hospital major adverse clinical events.

CONCLUSION

These results suggest that plasma ox-LDL, as well as T allele of ORL-1 (rs1050286), is associated with the increased risk for developing STEMI and the associated adverse clinical outcomes.

Association of OLR1 gene polymorphisms with the risk of coronary artery disease: A systematic review and meta-analysis

BACKGROUND

Oxidized LDL receptor 1 (OLR1) encodes LOX-1, LOXIN, and OLR1D4 transcript variants. Up-regulation of LOX-1 and down-regulation of LOXIN have an essential role in causing coronary artery disease (CAD). Discovery of risk single nucleotide polymorphisms (SNPs) in OLR1 gene is clinically important as these polymorphisms could be candidate biomarkers of CAD.

OBJECTIVES

The purpose of this study is quantitative evidence synthesis on how OLR1 polymorphisms in the haplotype block impact the risk of CAD.

METHODS

First, a systematic keyword-based search in PubMed, Web of Science, and Scopus was conducted. After data extraction, pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for OLR1 polymorphisms and CAD. Twelve case-control studies, including 6,238 cases and 15,773 controls, were concluded in the meta-analysis.

RESULTS

Our findings demonstrate significant association of OLR1 polymorphisms in the haplotype block with CAD risk in all genetic models (allelic model: OR = 1.19, 95%CI = 1.06-1.34; additive model: OR = 1.54, 95%CI = 1.16-2.05; recessive model: OR = 1.26, 95%CI = 1.04-1.53; dominant model: OR = 1.28, 95%CI = 1.09-1.51). Subgroup analysis based on the type of polymorphism revealed that rs1050283 (3'UTR*188 C > T) and rs3736235 (IVS4-14 A > G) are more significantly associated with the risk of CAD compared to other polymorphisms in the haplotype block.

CONCLUSIONS

We found a significant association between OLR1 polymorphisms in the haplotype block, especially rs1050283 and rs3736235, with CAD. We also suggest that precise determination of disease association with polymorphisms in a haplotype requires investigation of all SNPs rather than a single SNP in that specific haplotype.

Associations between Lectin-like, oxidized low-density lipoprotein receptor-1 G501C and 3'-UTR-C188T polymorphisms with coronary artery disease: a meta-analysis

The background and purpose: Published data on the association between LOX-1 3'UTR C188T and G501C polymorphisms with coronary artery disease (CAD) risk are inconclusive. In order to derive a more precise estimation of the relationship, a meta-analysis was conducted.

METHODS AND SUBJECTS

Crude ORs with 95% CIs were used to assess the strength of association between these polymorphisms and CAD risk. The pooled ORs were performed for homozygous model, heterozygous model, dominant model, and recessive model, respectively.

RESULTS

A total of seventeen studies were involved in the meta-analysis with 5006 cases and 15053 controls for LOX-1 3'UTR C188T polymorphism and with 5905 cases and 15050 controls for G501C polymorphism. For LOX-1 3'UTR C188T polymorphism, significantly elevated CAD risk was associated with variant genotype when all studies were pooled into the meta-analysis (TT vs. CC: OR = 1.35, 95% CI 1.08-1.69; dominant model: OR = 1.17, 95% CI 1.02-1.34; and recessive model: OR = 1.23, 95% CI 1.03-1.47). For LOX-1 G501C polymorphism, significantly increased CAD risk was also associated with variant genotype (GG vs. CC: OR = 1.42, 95% CI 1.07-1.87; CG vs. CC: OR = 1.28, 95% CI 1.04-1.56; and dominant model: OR = 1.30, 95% CI 1.07-1.58).

CONCLUSION

This meta-analysis suggests that the variant G allele of LOX1 3'UTR C188T and the variant C allele of G501C polymorphisms are low penetrant risk factors for developing CAD.

Polymorphisms in IL-10 and INF-γ genes are associated with early atherosclerosis in coronary but not in carotid arteries: A study of 122 autopsy cases of young adults

Atherosclerosis is a complex disease, involving both genetic and environmental factors. However, the influence of genetic variations on its early development remains unclear. This study examined the association of 12 different polymorphisms with atherosclerosis severity in anterior descending coronary (DA, n = 103) and carotid arteries (CA, n = 66) of autopsied young adults (< 30 years old). Histological sections (H-E) were classified according to the American Heart Association. Polymorphisms in ACE, TNF-α (− 308G/A and − 238 G/A), IFN-γ (+ 874 A/T), MMP-9 (− 1562 C/T), IL-10 (− 1082 A/G and − 819 C/T), NOS3 (894 G/T), ApoA1 (rs964184), ApoE (E2E3E4 isoforms), and TGF-β (codons 25 and 10) genes were genotyped by gel electrophoresis or automatic DNA sequencing. Firearm projectile or car accident was the main cause of death, and no information about classical risk factors was available. Histological analysis showed high prevalence of type III atherosclerotic lesions in both DA (69%) and CA (39%) arteries, while severe type IV and V lesions were observed in 14% (DA) and 33% (CA). Allele frequencies and genotype distributions were determined. Among the polymorphisms studied, IFN-γ and IL-10 (− 1082 A/G) were related to atherosclerosis severity in DA artery. No association between genotypes and lesion severity was found in CA. In conclusion, we observed that the high prevalence of early atherosclerosis in young adults is associated with IFN-γ (p < 0.001) and IL-10 (p = 0.013) genotypes. This association is blood vessel dependent. Our findings suggest that the vascular system presents site specialization, and specific genetic variations may provide future biomarkers for early disease identification.

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Twelve SNPs were associated with atherosclerosis severity in autopsied young adults.

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We found high prevalence of type III lesions in coronary and carotid arteries.

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Even severe lesions (types IV and V) were found in DA (14%) and CA (33%) arteries.

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Lesion severity was associated with IL-10 and IFN-γ genotype.

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The association was observed only in coronary, but not in carotid artery.

The discovery of LOX-1, its ligands and clinical significance

LOX-1 is an endothelial receptor for oxidized low-density lipoprotein (oxLDL), a key molecule in the pathogenesis of atherosclerosis.The basal expression of LOX-1 is low but highly induced under the influence of proinflammatory and prooxidative stimuli in vascular endothelial cells, smooth muscle cells, macrophages, platelets and cardiomyocytes. Multiple lines of in vitro and in vivo studies have provided compelling evidence that LOX-1 promotes endothelial dysfunction and atherogenesis induced by oxLDL. The roles of LOX-1 in the development of atherosclerosis, however, are not simple as it had been considered. Evidence has been accumulating that LOX-1 recognizes not only oxLDL but other atherogenic lipoproteins, platelets, leukocytes and CRP. As results, LOX-1 not only mediates endothelial dysfunction but contributes to atherosclerotic plaque formation, thrombogenesis, leukocyte infiltration and myocardial infarction, which determine mortality and morbidity from atherosclerosis. Moreover, our recent epidemiological study has highlighted the involvement of LOX-1 in human cardiovascular diseases. Further understandings of LOX-1 and its ligands as well as its versatile functions will direct us to ways to find novel diagnostic and therapeutic approaches to cardiovascular disease.

LOX-1/LOXIN: the yin/yang of atheroscleorosis

Atherosclerosis is the first cause of death in industrialized countries. Together with traditional risk factors (male gender, hypercholesterolemia, hypertension, diabetes, smoking and age), non-traditional risk factors have also been described as predisposing to this disease. Among these, oxidized low density lipoproteins (OxLDL) have been described in correlation to many proatherogenic processes. Many of the effects of OxLDL are mediated by the lectin like oxidized low density lipoprotein receptor 1 (LOX-1), expressed on endothelial cells, macrophages, SMCs and platelets. LOX-1 is encoded by the lectin like oxidized low density lipoprotein receptor 1 (OLR1) gene, located in the p12.3-p13.2 region of human chromosome 12. Variations on this gene have been studied extensively both at the functional and epidemiological level. Despite the fact that functional roles for two variants have been demonstrated, the epidemiological studies have provided inconsistent and inconclusive results. Of particular interest, it has been demonstrated that a linkage disequilibirum block of SNPs located in the intronic sequence of the OLR1 gene modulates the alternative splicing of OLR1 mRNA, leading to different ratios of LOX-1 full receptor and LOXIN, an isoform lacking part of the functional domain. As demonstrated, LOXIN acts by blocking the negative effective of LOX-1 activation. Here we review the state of the art regarding LOX-1, LOXIN, and the functional effects that are associated with the interaction of these molecules.

Association between OLR1 K167N SNP and intima media thickness of the common carotid artery in the general population

BACKGROUND AND PURPOSE

The lectin-like oxidised LDL receptor-1 (OLR1) gene encodes a scavenger receptor implicated in the pathogenesis of atherosclerosis. Although functional roles have been suggested for two variants, epidemiological studies on OLR1 have been inconsistent.

METHODS

We tested the association between the non-synonymous substitution K167N (rs11053646) and intima media thickness of the common carotid artery (CCA-IMT) in 2,141 samples from the Progression of Lesions in the Intima of the Carotid (PLIC) study (a prospective population-based study).

RESULTS

Significantly increased IMT was observed in male carriers of the minor C (N) allele compared to GC and GG (KN and KK) genotype. Functional analysis on macrophages suggested a decreased association to Ox-LDL in NN carriers compared to KN and KK carriers which is also associated with a reduced OLR1 mRNA expression. Macrophages from NN carriers present also a specific inflammatory gene expression pattern compared to cells from KN and KK carriers.

CONCLUSIONS

These data suggest that the 167N variant of LOX-1 receptor affects the atherogenic process in the carotid artery prior to evidence of disease through an inflammatory process.

Functional characterization and expression analysis of novel alternative splicing isoforms of Olr1 gene during mouse embryogenesis

LOX-1 (Lectin-like oxidized low-density lipoprotein receptor-1) is the primary endothelial receptor of oxidized LDL (oxLDL). Both in vitro and in vivo experiments have shown this protein to be important in the initiation of atherosclerosis and to be up-regulated by pro-atherogenic factors. Recently, it has been demonstrated that Olr1, the gene encoding Lox-1, is important for tumor growth and for maintaining the transformed state in different cancer cell lines, suggesting that it acts in a molecular pathway connecting cancer and atherosclerosis. Both diseases in humans are characterized by uncontrolled regulation of cellular growth and differentiation. We present evidence that Olr1 is expressed during mouse embryogenesis in developmental stages (from 7.5 to 9.5 dpc) in which cardiogenesis occurs. In addition, we identify two novel Olr1 isoform (hereafter referred to as D3D5Olr1 and D2D5Olr1) whose spatio-temporal expression pattern overlaps with Olr1 in vivo. In vitro, D3D5Olr1 localizes to the cell surface membrane as Olr1, in contrast with D2D5Olr1; these data suggest that D2D5Olr1 isoform translates a receptor that does not reach the plasma membrane. Accordingly, in silico transmembrane protein topology prediction analyses, show that D2D5Olr1 does not contain any transmembrane region. Finally, both isoforms can activate the same genetic pathways underlying Olr1 expression, such as, hypoxia and inflammation, even if with a different efficiency. All these data suggest a new functional involvement of Olr1, and probably of its spliceforms, in murine cardiogenesis and angiogenesis.

The LOX-1 3'UTR188CT polymorphism and coronary artery disease in Turkish patients

In coronary artery disease (CAD), a potentially reversible factor leading to cardiac death is left ventricular hypertrophy (LVH). The 3'untranslated region (3'UTR) 188CT polymorphism of lectin-like oxidized low-density lipoproteins receptor-1 (LOX-1) gene has been associated with an increased risk for CAD. We aim to investigate, in a Turkish population, whether 3'UTR188CT variation could affect the development of LVH in CAD patients. In a population-based case-control study, we compared 83 cases with CAD and 99 healthy controls for this polymorphism. The LOX-1 3'UTR188CT genotypes were determined by PCR-RFLP technique. LOX-1 3'UTR188 TT genotype was associated with significantly increased systolic blood pressure (P = 0.047) and risk of LVH (P = 0.014, OR: 3.541) when compared with the C allele carriers. In addition, the TT genotype was positively associated with decreased levels of HDL-cholesterol in the control subjects (P = 0.031) and increased levels of VLDL-C in the patient group (P = 0.009). The LOX-1 3'UTR188CT gene polymorphism may predispose to the development of LVH in CAD patients, dependent on blood pressure.

Associations between oxidized-lipoprotein receptor 1 G501C and 3'-UTR-C188T polymorphisms and coronary artery disease: a meta-analysis

OBJECTIVE

Previous case-control studies have suggested that the variations of the oxidized-lipoprotein receptor 1 (OLR1) gene (G501C, 3'-UTR-C188T) are associated with coronary artery disease (CAD). However, other studies have not confirmed this relationship. The objective of this study was to assess the relationship between OLR1 variations and CAD.

METHODS

We conducted a meta-analysis. Databases, including PubMed, EMbase, Chinese Biological Medical Literature Database (CBM), and China National Knowledge Infrastructure (CNKI), were searched to obtain genetic association studies. Data were extracted by two authors, and pooled odds ratios (OR) with 95% CI were calculated.

RESULTS

The meta-analysis included 8 studies with 4,963 cases and 14,864 controls for 3'-UTR-C188T and 9 studies with 5,660 cases and 15,405 controls for G501C. The pooled OR for 3'-UTR-188T was 1.29 (95% CI 1.05-1.58, p = 0.02) compared to the C allele in the dominant model, and it was 1.38 (95% CI 1.09-1.74, p = 0.007) in the recessive model. The pooled OR for 501C was 0.79 (95% CI 0.57-1.10, p = 0.16) compared to the G allele in the dominant model, and it was 0.86 (95% CI 0.71-1.04, p = 0.12) in the recessive model. No publication bias was found in the present meta-analysis.

CONCLUSION

The synthesis of available evidence supports that OLR1 3'-UTR-188T increases the susceptibility to CAD. However, G501C is not associated with CAD.

A candidate gene study revealed sex-specific association between the OLR1 gene and carotid plaque

BACKGROUND AND PURPOSE

Sex differences have been recognized in stroke risk; however, the sex-dependent genetic contribution to stroke is unclear. We sought to examine the sex-dependent associations between genes involved in lipid metabolism and carotid atherosclerotic plaque, a subclinical precursor of stroke.

METHODS

For the Genetic Determinant of Subclinical Carotid Disease study, 287 Dominicans ascertained through the Northern Manhattan Study were examined for carotid plaque using high-resolution ultrasound. Sixty-four single nucleotide polymorphisms (SNPs) in 11 lipid-related genes were genotyped. Plaque presence and plaque subphenotypes, including multiple, thick, irregular, and calcified plaque, were analyzed. First, the interaction between each SNP and sex was evaluated for association with each plaque phenotype using multiple logistic regression and controlling for age, smoking, and the main effects of sex and SNP. For SNPs with suggestive evidence for interaction with sex (P<0.1 for the interaction term), stratification analysis by sex was performed to evaluate the sex-specific association between the SNP and plaque phenotypes.

RESULTS

The most compelling finding is with the missense SNP rs11053646 (K167N) in the OLR1 gene, which encodes lectin-like oxidized low-density lipoprotein receptor. Stratification analysis revealed a strong association between rs11053646 and all plaque phenotypes in women (OR, 2.44 to 5.86; P=0.0003 to 0.0081) but not in men (OR, 0.85 to 1.22; P=0.77 to 0.92).

CONCLUSIONS

Genetic variation in genes involved in lipid metabolism may have sex-dependent effects on carotid plaque burden. Our findings provide a plausible biological basis underlying the sex difference in cardiovascular risk.

Scavenger receptors and their potential as therapeutic targets in the treatment of cardiovascular disease

Scavenger receptors act as membrane-bound and soluble proteins that bind to macromolecular complexes and pathogens. This diverse supergroup of proteins mediates binding to modified lipoprotein particles which regulate the initiation and progression of atherosclerotic plaques. In vascular tissues, scavenger receptors are implicated in regulating intracellular signaling, lipid accumulation, foam cell development, and cellular apoptosis or necrosis linked to the pathophysiology of atherosclerosis. One approach is using gene therapy to modulate scavenger receptor function in atherosclerosis. Ectopic expression of membrane-bound scavenger receptors using viral vectors can modify lipid profiles and reduce the incidence of atherosclerosis. Alternatively, expression of soluble scavenger receptors can also block plaque initiation and progression. Inhibition of scavenger receptor expression using a combined gene therapy and RNA interference strategy also holds promise for long-term therapy. Here we review our current understanding of the gene delivery by viral vectors to cells and tissues in gene therapy strategies and its application to the modulation of scavenger receptor function in atherosclerosis.

Genetic polymorphisms of Chinese patients with ischemic stroke and concurrent stenoses of extracranial and intracranial vessels

The etiology of concurrent stenoses of extracranial and intracranial vessels in patients with ischemic stroke is poorly understood, but hereditary factors are believed to be important. We aimed to determine whether genetic polymorphisms affecting homocysteine and lipid metabolism are associated with concurrent stenoses. The genotypes of 191 Han Chinese patients with acute ischemic stroke, of whom 47 (25%) had concurrent stenoses, and 167 healthy control patients in Hong Kong were examined for the following polymorphisms: paraoxonase 1 (PON1) Q192R, methylenetetrahydrofolate reductase (MTHFR) A222V, glutamate-cysteine ligase catalytic-subunit (GCLC)-129C>T, and oxidized low-density lipoprotein receptor (OLR) 3' untranslated region C>T (rs1050283). The genotype distributions of PON1 Q192R and MTHFR A222V, which affect lipid and homocysteine metabolism, differed significantly between patients with stroke and healthy controls. The presence of at least one R allele in PON1 Q192R and a TT allele in OLR rs1050283 were associated with concurrent stenoses. We also identified a possible association between the presence of at least one V allele in MTHFR A222V and concurrent stenoses. This study shows that genetic polymorphisms affecting homocysteine and lipid metabolism are possible risk factors for stroke and concurrent stenoses.

The lectin-like oxidized low-density lipoprotein receptor-1 and its soluble form: cardiovascular implications

The lectin-like oxidized low density lipoprotein receptor-1 (LOX-1) is a multiligand receptor, whose repertoire of ligands includes oxidized low-density lipoprotein, advanced glycation endproducts, platelets, neutrophils, apoptotic/aged cells and bacteria. Sustained expression of LOX-1 by critical target cells, including endothelial cells, smooth muscle cells and macrophages in proximity to these ligands, sets the stage for chronic cellular activation and tissue damage suggesting the interaction of cellular LOX-1 with its ligands to contribute to the formation and development of atherosclerotic plaques. Studies with transgenic and knockout mouse models have elucidated in part the role of LOX-1 in the pathogenesis of atherosclerosis and cardiac remodeling. Recently, a circulating soluble form of LOX-1 (sLOX-1), corresponding solely to its extracellular domain, has been identified in human serum. Circulating levels of sLOX-1 are increased in inflammatory and atherosclerotic conditions and are associated with acute coronary syndrome, with the severity of coronary artery disease, and with serum biomarkers for oxidative stress and inflammation, suggesting that they could be a useful marker for vascular injury. However, many interesting questions have not yet been answered and in this review, we provide an updated overview of the literature on this receptor and on likely future directions.

Lox-1: the multifunctional receptor underlying cardiovascular dysfunction

Oxidatively modified low-density lipoprotein (oxLDL) is implicated in the pathogenesis of atherosclerosis. Endothelial dysfunction is the initial change in the vascular wall that induces morphological changes for atheroma-formation. Lectin-like oxidized LDL receptor-1 (LOX-1) was identified as the receptor for oxLDL that was thought to be a major cause of endothelial dysfunction. LOX-1 has been demonstrated to contribute not only to endothelial dysfunction, but also to atherosclerotic-plaque formation, myocardial infarction and intimal thickening after balloon injury. Recent findings on the genetics of LOX-1 and the methodology to detect it and its ligands would further facilitate the examination of the receptor's pathophysiological contribution in atherosclerosis. Furthermore, LOX-1-related tools might open new gateways from diagnosis to therapeutics for cardiovascular diseases.

Functional analysis and molecular dynamics simulation of LOX-1 K167N polymorphism reveal alteration of receptor activity

The human lectin-like oxidized low density lipoprotein receptor 1 LOX-1, encoded by the ORL1 gene, is the major scavenger receptor for oxidized low density lipoprotein in endothelial cells. Here we report on the functional effects of a coding SNP, c.501G>C, which produces a single amino acid change (K>N at codon 167). Our study was aimed at elucidating whether the c.501G>C polymorphism changes the binding affinity of LOX-1 receptor altering its function. The presence of p.K167N mutation reduces ox-LDL binding and uptake. Ox-LDL activated extracellular signal-regulated kinases 1 and 2 (ERK 1/2) is inhibited. Furthermore, ox-LDL induced biosynthesis of LOX-1 receptors is dependent on the p.K167N variation. In human macrophages, derived from c.501G>C heterozygous individuals, the ox-LDL induced LOX-1 46 kDa band is markedly lower than in induced macrophages derived from c.501G>C controls. Investigation of p.K167N mutation through molecular dynamics simulation and electrostatic analysis suggests that the ox-LDL binding may be attributed to the coupling between the electrostatic potential distribution and the asymmetric flexibility of the basic spine residues. The N/N-LOX-1 mutant has either interrupted electrostatic potential and asymmetric fluctuations of the basic spine arginines.

The fungal pattern recognition receptor, Dectin-1, and the associated cluster of C-type lectin-like receptors

The mammalian natural killer gene complex (NKC) contains several families of type II transmembrane C-type lectin-like receptors (CLRs) that are best known for their involvement in the detection of virally infected or transformed cells, through the recognition of endogenous (or self) proteinacious ligands. However, certain CLR families within the NKC, particularly those expressed by myeloid cells, recognize structurally diverse ligands and perform a variety of other immune and homoeostatic functions. One such family is the 'Dectin-1 cluster' of CLRs, which includes MICL, CLEC-2, CLEC12B, CLEC9A, CLEC-1, Dectin-1 and LOX-1. Here, we review each of these CLRs, exploring our current understanding of their ligands and functions and highlighting where they have provided new insights into the underlying mechanisms of immunity and homeostasis.