scholarly journals Association between Negatively Charged Low-Density Lipoprotein L5 and Subclinical Atherosclerosis in Rheumatoid Arthritis Patients

2019 ◽  
Vol 8 (2) ◽  
pp. 177 ◽  
Author(s):  
Chun-Yu Chang ◽  
Chu-Huang Chen ◽  
Yi-Ming Chen ◽  
Tsu-Yi Hsieh ◽  
Ju-Pi Li ◽  
...  

L5, the most negatively charged subfraction of low-density lipoprotein (LDL), is implicated in atherogenesis. We examined the relationship between plasma L5 levels and the occurrence of subclinical atherosclerosis in patients with rheumatoid arthritis (RA). Using anion-exchange purification with fast-protein liquid chromatography, we determined the proportion of plasma L5 of LDL (L5%) in 64 RA patients and 12 healthy controls (HC). Plasma L5% and L5 levels were significantly higher in RA patients (median, 1.4% and 1.92 mg/dL) compared with HC (0.9%, p < 0.005; and 1.27 mg/dL, p < 0.05) and further increased in patients with subclinical atherosclerosis (2.0% and 2.88 mg/dL). L5% and L5 levels decreased in patients after 6-months of therapy (p < 0.01). Subclinical atherosclerosis was indicated by plaque and intima-media thickness determined by carotid ultrasonography. Using multivariate analysis, L5% and L5 levels are revealed as the predictors of subclinical atherosclerosis (odds ratio, 4.94 and 1.01; both p < 0.05). Receiver operating characteristic curves showed that cut-off values of L5% ≥ 1.45% and L5 levels ≥ 2.58 mg/dL could predict subclinical atherosclerosis in patients (both p < 0.001). Immunoblotting showed that the expression levels of lectin-like oxidized LDL receptor-1 (LOX-1) was increased in RA patients. Together, our findings suggest that plasma L5% and L5 levels may be predictors of cardiovascular risk in RA patients.

Author(s):  
Alexander Akhmedov ◽  
Tatsuya Sawamura ◽  
Chu-Huang Chen ◽  
Simon Kraler ◽  
Daria Vdovenko ◽  
...  

Abstract Cardiovascular diseases (CVDs), specifically lipid-driven atherosclerotic CVDs, remain the number one cause of death worldwide. The lectin-like oxidized low-density lipoprotein (LDL) receptor-1 (LOX-1), a scavenger receptor that promotes endothelial dysfunction by inducing pro-atherogenic signalling and plaque formation via the endothelial uptake of oxidized LDL (oxLDL) and electronegative LDL, contributes to the initiation, progression, and destabilization of atheromatous plaques, eventually leading to the development of myocardial infarction and certain forms of stroke. In addition to its expression in endothelial cells, LOX-1 is expressed in macrophages, cardiomyocytes, fibroblasts, dendritic cells, lymphocytes, and neutrophils, further implicating this receptor in multiple aspects of atherosclerotic plaque formation. LOX-1 holds promise as a novel diagnostic and therapeutic target for certain CVDs; therefore, understanding the molecular structure and function of LOX-1 is of critical importance. In this review, we highlight the latest scientific findings related to LOX-1, its ligands, and their roles in the broad spectrum of CVDs. We describe recent findings from basic research, delineate their translational value, and discuss the potential of LOX-1 as a novel target for the prevention, diagnosis, and treatment of related CVDs.


1970 ◽  
Vol 3 (2) ◽  
pp. 169-177
Author(s):  
MSA Sheikh ◽  
T Yang ◽  
U Salma ◽  
M Ali

Lectin-like oxidized LDL receptor-1 (LOX-1), a lectin-like 50-kD receptor for oxidized low-density lipoproteins (ox-LDL), is present primarily on endothelial cells. 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. 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, hypertension, myocardial infarction and intimal thickening after balloon injury. 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 useful marker for vascular injury. Identification and regulation of this receptor and understanding of signal transduction pathways might open new gateways from diagnosis to therapeutics for cardiovascular diseases. Keywords: Atherosclerosis; Endothelial dysfunction; LOX-1; ox-LDL; Signal transduction. DOI: http://dx.doi.org/10.3329/cardio.v3i2.9187 Cardiovasc. J. 2011; 3(2): 169-177


1999 ◽  
Vol 339 (1) ◽  
pp. 177-184 ◽  
Author(s):  
Takuma AOYAMA ◽  
Tatsuya SAWAMURA ◽  
Yoshiyuki FURUTANI ◽  
Rumiko MATSUOKA ◽  
Michihiro C. YOSHIDA ◽  
...  

We have reported the cDNA cloning of a modified low-density-lipoprotein (LDL) receptor, designated lectin-like oxidized LDL receptor-1 (LOX-1), which is postulated to be involved in endothelial dysfunction and the pathogenesis of atherosclerosis. Here, we determined the organization of the human LOX-1 gene, including the 5´-regulatory region. The 5´-regulatory region contained several potential cis-regulatory elements, such as GATA-2 binding element, c-ets-1 binding element, 12-O-tetradecanoylphorbol 13-acetate-responsive element and shear-stress-responsive elements, which may mediate the endothelium-specific and inducible expression of LOX-1. The major transcription-initiation site was found to be located 29 nucleotides downstream of the TATA box and 61 nucleotides upstream from the translation-initiation codon. The minor initiation site was found to be 5 bp downstream from the major site. Most of the promoter activity of the LOX-1 gene was ascribed to the region (-150 to -90) containing the GC and CAAT boxes. The coding sequence was divided into 6 exons by 5 introns. The first 3 exons corresponded to the different functional domains of the protein (cytoplasmic, transmembrane and neck domains), and the residual 3 exons encoded the carbohydrate-recognition domain similar to the case of other C-type lectin genes. The LOX-1 gene was a single-copy gene and assigned to the p12.3–p13.2 region of chromosome 12. Since the locus for a familial hypertension has been mapped to the overlapping region, LOX-1 might be the gene responsible for the hypertension.


2011 ◽  
Vol 83 (9) ◽  
pp. 1731-1740 ◽  
Author(s):  
Liang-Yin Ke ◽  
David A. Engler ◽  
Jonathan Lu ◽  
Risë K. Matsunami ◽  
Hua-Chen Chan ◽  
...  

Anion-exchange chromatography resolves human plasma low-density lipoprotein (LDL) into 5 subfractions, with increasing negative surface charge in the direction of L1 to L5. Unlike the harmless L1 to L4, the exclusively atherogenic L5 is rejected by the normal LDL receptor (LDLR) but endocytosed into vascular endothelial cells (ECs) through the lectin-like oxidized LDL receptor-1 (LOX-1). Analysis with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and 2-dimensional electrophoresis showed that the protein framework of L1 was composed mainly of apolipoprotein (apo) B100, with an isoelectric point (pI) of 6.620. There was a progressively increased association of additional proteins, including apoE (pI 5.5), apoAI (pI 5.4), apoCIII (pI 5.1), and apo(a) (pI 5.5), from L1 to L5. Liquid chromatography data-independent parallel-fragmentation mass spectrometry (LC/MSE) was used to quantify protein distribution in all subfractions. On the basis of weight percentages, L1 contained 99 % apoB-100 and trace amounts of other proteins. In contrast, L5 contained 60 % apoB100 and substantially increased amounts of apo(a), apoE, apoAI, and apoCIII. The compositional characteristics contribute to L5’s electronegativity, rendering it unrecognizable by LDLR. LOX-1, which has a high affinity for negatively charged ligands, is known to mediate the signaling of proinflammatory cytokines. Thus, the chemical composition-oriented receptor selectivity hinders normal metabolism of L5, enhancing its atherogenicity through abnormal receptors, such as LOX-1.


2016 ◽  
Vol 40 (6) ◽  
pp. 1521-1528 ◽  
Author(s):  
Yu-Qing Huang ◽  
An-Ping Cai ◽  
Ji-Yan Chen ◽  
Cheng Huang ◽  
Jie Li ◽  
...  

Background/Aims: Atherosclerosis is a chronic inflammatory condition associated with a variety of vascular diseases. Previous studies showed that both miR-29a and oxidized low density lipoprotein (ox-LDL) were vital in the development of atherosclerosis. However, the relationship between miR-29a and ox-LDL remains unknown. This study was designed to investigate the association of miR-29a and ox-LDL and to test whether circulating miR-29a and ox-LDL levels could predict atherosclerosis. Methods: In 170 participants, plasma levels of miR-29a were assessed by quantitative real-time polymerase chain reaction (qRT-PCR) while plasma ox-LDL levels were determined using enzyme-linked immunosorbent assay (ELISA) kits. The relationship between miR-29a level and ox-LDL and carotid intima-media thickness (cIMT) was assessed using the Spearman correlation coefficient and multiple liner regression. Results: Compared with the normal cIMT group, the increased cIMT group had higher levels of ox-LDL (0.47 ± 0.08 vs 0.29 ± 0.06 ng/ml, p = 0.003) and miR-29a (32.93 ± 4.26 vs 26.37 ± 1.04, p < 0.001). A positive correlation was found between ox-LDL and miR-29a (r = 0.695, p < 0.001), and both the ox-LDL (r = 0.857, p < 0.001) and the miR-29a (r = 0.753, p < 0.001) were positively related to cIMT. Furthermore, multiple liner regression indicated that a significant correlation between ox-LDL and cIMT (β = 0.768, p < 0.001), as well as between miR-29a and cIMT (β = 0.686, p <0.001). The combination of miR-29a and ox-LDL (AUC = 0.926, p < 0.001) offered a better predictive value for atherosclerosis than either miR-29a (AUC = 0.759, p < 0.001) or ox-LDL (AUC = 0.762, p < 0.001) alone. Conclusion: Increased miR-29a and ox-LDL levels were associated with an early stage of atherosclerosis, and the combination of miR-29a and ox-LDL offered better predictive values for atherosclerosis than either alone.


Author(s):  
Eline Verhoye ◽  
Michel R. Langlois

AbstractLow-density lipoproteins (LDLs) are susceptible to structural modifications by oxidation, particularly the small dense LDL particles. The formation of lipid peroxidation derivates, such as thiobarbituric reactive substances, conjugated dienes, lipid hydroperoxides, and aldehydes, is associated with changes in apolipoprotein conformation and affects the functional properties of LDLs. Oxidized LDL (oxLDL) formation in the subendothelial space of the arterial wall is a key initiating step in atherosclerosis because it contributes to foam cell generation, endothelial dysfunction, and inflammatory processes. In the last decade, immunoassays were developed using monoclonal antibodies against oxidation-dependent epitopes of LDL which made it possible to directly measure oxLDL in the circulation. Increased circulating oxLDL concentrations have been related to cardiovascular disease in some studies, although not always independently after adjustment of classical lipid markers. The Asklepios Study, investigating 2524 healthy middle-aged subjects, showed that circulating oxLDL is affected by many biological and lifestyle factors, as well as (generalized) subclinical atherosclerosis.Clin Chem Lab Med 2009;47:128–37.


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