Platelet-endothelial cell adhesion molecule-1 gene polymorphism and its soluble level are associated with severe coronary artery stenosis in Chinese Singaporean

Diabetes-induced early molecular and functional changes in aortic heart valves in a murine model of atherosclerosis

Diabetes contributes directly to the development of cardiovascular aortic valve disease. There is currently no drug therapy available for a dysfunctional valve and this urges the need for additional research to identify distinctive mechanisms of cardiovascular aortic valve disease evolution. The aim of this study was to evaluate changes of valvular aortic lesions induced in a hyperlipemic ApoE^-/- mouse model by early type 1 diabetes onset (at 4 and 7 days after streptozotocin induction). The haemodynamic valve parameters were evaluated by echography and blood samples and aortic valves were collected. Plasma parameters were measured, and inflammatory, remodelling and osteogenic markers were evaluated in the aortic valves. Next, correlations between all parameters were determined. The results showed early aortic valve dysfunction detected by echography after 1 week of diabetes; lesions were found in the aortic root. Moreover, increased expression of cell adhesion molecules, extracellular matrix remodelling and osteogenic markers were detected in hyperlipemic ApoE^-/- diabetic mice. Significant correlations were found between tissue valve biomarkers and plasmatic and haemodynamic parameters. Our study may help to understand the mechanisms of aortic valve disease in the diabetic milieu in order to discover and validate new biomarkers of cardiovascular aortic valve disease in diabetes and reveal new possible targets for nanobiotherapies.

Association of PECAM-1 Gene Polymorphisms with Kawasaki Disease in Chinese Children

Kawasaki disease (KD) is an acute systemic vasculitis complicated by development of coronary artery lesions. PECAM-1 is a kind of cell adhesion molecule, which plays an important role in coronary artery disease. The relationship between PECAM-1 gene polymorphisms and their susceptibility to Kawasaki diseases (KD) is still unclear. In our study, we examined the PECAM-1 gene polymorphisms in 44 KD patients and 59 healthy children and revealed the correlation of PECAM-1 gene polymorphisms in KD children with and without coronary artery lesions (CAL).

PECAM-1 Leu125Val (rs688) Polymorphism and Diabetic Nephropathy in Caucasians with Type 2 Diabetes Mellitus

Objectives. Platelet endothelial cell adhesion molecule-1 (PECAM-1) plays a key role in the transendothelial migration of circulating leukocytes during inflammation and in the maintenance of vascular endothelial integrity. We hypothesized that genetic variation in PECAM-1 gene could be associated with diabetic nephropathy (DN) and with the level of soluble PECAM-1 in Caucasians with type 2 diabetes mellitus (T2DM). Design and Methods. We analyzed the rs688 single nucleotide polymorphism of PECAM-1 gene C373G (Leu125Val) at exon 3, which encodes the first extracellular Ig-like domain that mediates the homophilic binding of PECAM-1, in 276 T2DM subjects with documented DN (cases) and 375 T2DM subjects without DN (controls), using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) strategy. Level of plasma soluble PECAM-1 (sPECAM-1) was measured by ELISA in a subpopulation of 120 diabetics with DN. Results. We found no association between the Leu125Val polymorphism and DN in subjects with T2DM. Likewise, the Leu125Val polymorphism was not associated with serum sPECAM-1 levels in a subpopulation of 120 diabetics with DN. Conclusion. The Leu125Val polymorphism of PECAM-1 and the level of sPECAM-1 are not associated with DN in T2DM subjects of Slovenian origin.

PECAM-1 gene polymorphism (rs668) and subclinical markers of carotid atherosclerosis in patients with type 2 diabetes mellitus

The platelet endothelial cell adhesion molecule 1 (PECAM-1) plays an important role in many inflammatory processes, including the development of atherosclerosis. Polymorphism rs668 of the PECAM-1 gene (373C/G) is functional, and it was reported to be associated with increased serum levels of PECAM-1. We investigated the association between the rs668 polymorphism of PECAM-1 and subclinical markers of carotid atherosclerosis in subjects with type 2 diabetes mellitus (T2DM). Five hundred and ninety-five T2DM subjects and 200 control subjects were enrolled. The carotid intima-media thickness (CIMT) and plaque characteristics (presence and structure) were assessed ultrasonographically. Biochemical analyses were performed using standard biochemical methods. Geno-typing of the PECAM-1 gene polymorphism (rs668) was performed using KASPar assays. The control examinations were performed 3.8 ± 0.5 years after the initial examination. Higher CIMT was found in patients with T2DM in comparison with subjects without T2DM. Statistically sig-nificantly faster progression of the atherosclerotic markers was shown in subjects with T2DM in comparison with the control group. When adjusted to other risk factors, the rs668 GG genotype was associated with an increased risk of carotid plaques in subjects with T2DM. We concluded that our study demonstrated a minor effect of the rs668 PECAM-1 on markers of carotid atherosclerosis in subjects with T2DM.

Increased proatherogenic monocyte-platelet cross-talk in monocyte subpopulations of patients with stable coronary artery disease

BACKGROUND

Monocytes and platelets are important cellular mediators of atherosclerosis. Human monocytes can be divided into CD14(++) CD16(-) , CD14(++) CD16(+) and CD14(+) CD16(++) cells, which differ in their functional properties. The aim of this study was to examine monocyte subset distribution, monocyte-platelet aggregate (MPA) formation and expression of CCR5, the receptor of the platelet-derived chemokine CCL5, and to determine whether these parameters are altered in individuals with coronary atherosclerosis.

METHODS

Peripheral blood cells from 64 healthy blood donors (HBDs) and 60 patients with stable coronary artery disease (CAD) were stained with antibodies against CD14, CD16, CD42b and CCR5 and analysed by flow cytometry. Circulating CCL5 levels were determined using an enzyme-linked immunosorbent assay.

RESULTS

In patients with CAD, the relative proportion of the CD14(++) CD16(-) monocyte subset was elevated (P < 0.05) and of the CD14(+) CD16(++) subset was reduced (P < 0.001) compared with the HBD group. Furthermore, MPA formation significantly increased in patients with CAD in all three monocyte subsets. In both study groups, the majority of CCR5(+) cells was detected in CD14(++) CD16(+) monocytes (P < 0.001 versus CD14(++) CD16(-) and CD14(+) CD16(++) ), although the CCR5(+) monocyte number was reduced in patients with CAD (CD14(++) CD16(-) /CD14(+) CD16(++) , P < 0.001; CD14(++) CD16(+) , P < 0.05) compared with the HBD group, particularly in those who were not taking statins. Ex vivo incubation of monocytes from HBDs with plasma from patients with CAD also decreased CCR5(+) expression (P < 0.05 versus plasma from HBDs). Serum CCL5 levels were similar in both groups.

CONCLUSIONS

The increased monocyte-platelet cross-talk in patients with CAD might have contributed to atherosclerosis progression. The decreased CCR5(+) monocyte numbers in patients with CAD could have resulted from CCR5(+) cell recruitment into atherosclerotic lesions or CCR5 downregulation in response to circulating factors.

Association of single nucleotide polymorphisms in the gene encoding platelet endothelial cell adhesion molecule-1 with the risk of myocardial infarction: a systematic review and meta-analysis

BACKGROUND

Single nucleotide polymorphisms (SNPs) within the platelet endothelial cell adhesion molecule-1 (PECAM-1) gene have been proposed as predisposing factors for myocardial infarction (MI) but published reports have given conflicting findings.

OBJECTIVE

The present study aimed to clarify the association between SNPs in PECAM-1 and MI using a meta-analysis of published studies.

METHODS

Medline, HuGE Navigator and SCOPUS Library databases were searched to identify case-control studies which examined the association of SNPs in PECAM-1 and MI. Data were extracted using standardized methods. Combined odds ratios (OR) with 95% confidence intervals (CI) for the association of SNPs with MI were calculated using a random effect approach and under additive, dominant and recessive models of inheritance.

RESULTS

A total of 7 studies comprising 3886 cases and 4097 controls fulfilled the inclusion criteria. Three SNPs in PECAM-1 were investigated, namely rs668 (Leu125Val), rs12953 (Ser563Asn) and rs1131012 (Arg670Gly). The GG genotype of rs1131012 was associated with a reduced risk of MI under a recessive (OR: 0.81; 95%CI: 0.69-0.94; p=0.010), but not additive and dominant models (p>0.05). This association was robust in sensitivity analyses and not subject to heterogeneity. No significant association was detected between rs668 and rs12953 with MI under any of the inheritance models.

CONCLUSION

The results of the current meta-analysis suggest that homozygous polymorphic genotype (GG) of the rs1131012 SNP may confer protection against MI. The impact of this variant on the expression and function of PECAM-1 needs to be elucidated in future investigations.

Leucine125Valine (Leu125Val) Gene Polymorphism of Platelet Endothelial Cell Adhesion Molecule-1 (PECAM-1) and Myocardial Infarction in Indian Population

Platelet-endothelial cell adhesion molecule-1 (PECAM-1) has role in atherosclerotic plaque development as well as in thrombosis leading to myocardial infarction (MI). Present study was aimed to analyse the association of PECAM-1 Leu125Val gene polymorphism with MI in Indian population. Subjects included healthy individuals as control (N = 116) and MI patients (N = 100) divided into two groups; MI patients at presentation of the acute event (MI-Group-1, N = 46) and patients with recent event of MI stabilized with treatment 4.5 days from their symptoms (MI-Group-2, N = 54). The difference in the distribution of Leu125Val genotype frequencies of controls and patients did not reach statistical significance. However Leu allele frequency (0.57) was more associated with MI patients as compared to control (0.504). sPECAM-1 levels were significantly elevated in patients at acute event of MI (MI-Group-1) by 44.1% (P = 0.009) as compared to controls and by 95.2% (P = 0.001) as compared to stabilized MI patients (MI-Group-2).

Association between platelet endothelial cellular adhesion molecule-1 polymorphisms and atherosclerosis: results of a study on patients from northern Italy

Adhesion of circulating cells to the arterial surface is among the first detectable events in atherogenesis. Cellular adhesion molecules, expressed by the vascular endothelium and by circulating leukocytes, mediate cell recruitment and their transendothelial migration. Platelet endothelial cellular adhesion molecule-1 (PECAM-1), involved in this migration, has been associated with the development of atherosclerosis. Studies have investigated an association between coronary artery disease (CAD) and single-nucleotide polymorphisms (SNPs) located in functionally important domains of the PECAM-1 gene with inconsistent results. Thus, we have analyzed the distribution of V125L, N563S, and G670R SNPs in patients and controls from northern Italy, and also analyzed another functional variant identified in the 5'-untranslated region (UTR) of the PECAM-1 gene (53 G-->A). The polymorphisms of PECAM-1 were genotyped by PCR amplification with sequence-specific primers (PCR-SSP) in 119 controls and 431 CAD patients. Our results demonstrate that genotype and allele frequencies for the 53 G/A polymorphism are significantly different in patients affected by CAD compared to healthy controls, whereas, as regards the V125L and N563S polymorphisms, only the allelic frequency is significantly different. We have shown that there were a significant differences for the 53 G/A and V125L and N563S polymorphisms of PECAM-1 in patients affected by CAD compared to controls. This demonstrates a possible involvement of this gene in contributing to the development of CAD. Therefore, an understanding of the role of the PECAM-1 molecule in this complex mechanism is of pivotal significance in further development of innovative and suitable medical therapies in the future.

Platelet-endothelial cell adhesion molecule-1 gene polymorphism and its soluble level are associated with ischemic stroke

Inflammation, characterized by the recruitment and adhesion of circulating leukocytes by cellular adhesion molecules, plays an important role in the pathogenesis of atherosclerosis. Genetic analyses of platelet-endothelial cell adhesion molecule-1 (PECAM-1), a key adhesion molecule in the progression of atherosclerosis, have provided conflicting results regarding the role of variation within the PECAM-1 gene and risk for coronary heart disease. No studies have examined the association of this polymorphism with ischemic stroke. Therefore, we investigated that PECAM-1 gene polymorphism and its soluble level are associated with ischemic stroke in Chinese population. We analyzed single-nucleotide polymorphisms of PECAM-1 gene Leu125Val, Asn563Ser, and Gly670Arg in 265 patients with ischemic stroke and 280 age- and sex-matched controls, using polymerase chain reaction-restriction fragment length polymorphism and DNA sequencing method, while soluble PECAM-1 (sPECAM-1) levels were measured by enzyme-linked immunosorbent assay. There were significant differences in the genotype and allele frequencies of PECAM-1 gene Leu125Val polymorphism between the group of patients with ischemic stroke and the control group (p < 0.05). sPECAM-1 levels were increased in patients with ischemic stroke compared with controls (p < 0.01). Moreover, genotypes carrying the PECAM-1 125Val variant allele were associated with increased PECAM-1 levels compared to the homozygous wild-type genotype in patients with ischemic stroke. The Leu125Val polymorphism of PECAM-1 and its sPECAM-1 levels are associated with ischemic stroke in Chinese population. Our data suggest that the PECAM-1 gene may play a role in the development of ischemic stroke.

PECAM-1: conflicts of interest in inflammation

Platelet endothelial cell adhesion molecule-1 (PECAM-1, CD31) is a cell adhesion and signaling receptor that is expressed on hematopoietic and endothelial cells. PECAM-1 is vital to the regulation of inflammatory responses, as it has been shown to serve a variety of pro-inflammatory and anti-inflammatory functions. Pro-inflammatory functions of PECAM-1 include the facilitation of leukocyte transendothelial migration and the transduction of mechanical signals in endothelial cells emanating from fluid shear stress. Anti-inflammatory functions include the dampening of leukocyte activation, suppression of pro-inflammatory cytokine production, and the maintenance of vascular barrier integrity. Although PECAM-1 has been well-characterized and studied, the mechanisms through which PECAM-1 regulates these seemingly opposing functions, and how they influence each other, are still not completely understood. The purpose of this review, therefore, is to provide an overview of the pro- and anti-inflammatory functions of PECAM-1 with special attention paid to mechanistic insights that have thus far been revealed in the literature in hopes of gaining a clearer picture of how these opposing functions might be integrated in a temporal and spatial manner on the whole organism level. A better understanding of how inflammatory responses are regulated should enable the development of new therapeutics that can be used in the treatment of acute and chronic inflammatory disorders.

TCR stimulation drives cleavage and shedding of the ITIM receptor CD31

CD31 is a transmembrane molecule endowed with T cell regulatory functions owing to the presence of 2 immunotyrosine-based inhibitory motifs. For reasons not understood, CD31 is lost by a portion of circulating T lymphocytes, which appear prone to uncontrolled activation. In this study, we show that extracellular T cell CD31 comprising Ig-like domains 1 to 5 is cleaved and shed from the surface of human T cells upon activation via their TCR. The shed CD31 can be specifically detected as a soluble, truncated protein in human plasma. CD31 shedding results in the loss of its inhibitory function because the necessary cis-homo-oligomerization of the molecule, triggered by the trans-homophilic engagement of the distal Ig-like domain 1, cannot be established by CD31(shed) cells. However, we show that a juxta-membrane extracellular sequence, comprising part of the domain 6, remains expressed at the surface of CD31(shed) T cells. We also show that the immunosuppressive CD31 peptide aa 551-574 is highly homophilic and possibly acts by homo-oligomerizing with the truncated CD31 remaining after its cleavage and shedding. This peptide is able to sustain phosphorylation of the CD31 ITIM(686) and of SHP2 and to inhibit TCR-induced T cell activation. Finally, systemic administration of the peptide in BALB/c mice efficiently suppresses Ag-induced T cell-mediated immune responses in vivo. We conclude that the loss of T cell regulation caused by CD31 shedding driven by TCR stimulation can be rescued by molecular tools able to engage the truncated juxta-membrane extracellular molecule that remains exposed at the surface of CD31(shed) cells.

The PECAM-1 gene polymorphism — a genetic marker of myocardial infarction

We investigated a possible association between the C373G (Leu125Val) polymorphism in the platelet endothelial cell adhesion molecule-1 (PECAM-1) and myocardial infarction (MI) among patients with type 2 diabetes (T2DM) in the Slovene population (Caucasians). The study population of this cross-sectional analysis consisted of 452 subjects with T2DM lasting more than 10 years: 142 patients with MI (MI group) and 310 patients (control group) with no history of coronary diseases. There were significant differences of PECAM-1 genotype distribution in patients with MI (CC=28.2%, CG=47.2% and GG=24.6%) compared with subjects in the control group (CC=17.1%, CG=53.5% and GG=29.4%). The multivariate model showed that the CC genotype of the PECAM-1 gene polymorphism (C373G) (OR=1.9, 95% CI 1.2–3.0, P=0.007) was an independent risk factor for MI. The C allele frequency was also significantly higher (P=0.005) in MI (51.8%) than in control subjects (41%). In addition, our study revealed the connection between smoking habits, the duration of diabetes and the total and LDL cholesterol serum levels and MI in Slovene T2DM patients. We suggest that the tested polymorphism of PECAM-1 (C373G) is associated with MI. Therefore, it might be used as genetic marker of MI in T2DM.

ICAM-1 (Lys469Glu) and PECAM-1 (Leu125Val) polymorphisms in diffuse astrocytomas

Cell adhesion molecules such as intercellular adhesion molecule-1 (ICAM-1) and platelet-endothelial cell adhesion molecule-1 (PECAM-1) play an important role in glioma invasion and angiogenesis. The aim of this study was to investigate whether specific genetic polymorphisms of ICAM-1 and PECAM-1 could be associated with glioma development and progression. Single-nucleotide polymorphism in codon 469 of ICAM-1 and codon 125 of PECAM-1 were examined in 158 patients with astrocytomas and 162 controls using polymerase chain reaction and restriction enzyme analysis. The distribution of PECAM-1 polymorphic genotypes in astrocytomas did not show any significant difference. However, a specific ICAM-1 genotype (G/G, corresponding to Lys469Glu) exhibited higher frequency in grade II astrocytomas compared to controls, grade III, and grade IV astrocytomas; suggesting that this polymorphism could be involved in the development of grade II astrocytomas.

Effects of niacin on cell adhesion and early atherogenesis: biochemical and functional findings in endothelial cells

Atherosclerotic cardiovascular disease is a major cause of morbidity and mortality. Increased expression of cell adhesion molecules (CAM) and their ligands mediate essential processes in atherogenesis. Niacin reduces atherosclerotic cardiovascular complications and total mortality. Further understanding is needed on effects of niacin on CAM, and its functional consequences. The aim of this study was to evaluate the effects of niacin on CAM expression and monocyte adhesion in endothelial cells. Endothelial cells (HUVEC) were cultured to reach 80-90% confluence before experiments were initiated. Cells were exposed to DME/F12 with selected concentrations of niacin. To elicit the expression of CAM, cells were stimulated by addition of tumour necrosis factor (TNF)-alpha, interleukin (IL)-1 or interferon-gamma. Lysate from the conditioned media was assayed for CAM. The effect of niacin on mRNA expression of ICAM-1 was studied using semi-quantitative analysis of ICAM-1 mRNA. Adhesion assays were performed with flow cytometry to study the functional significance of the effects niacin on CAM expression. Niacin significantly reduced ICAM-1 and PECAM-1 protein levels basally, and reduced the cytokine-induced rise in ICAM-1, with a similar effect for TNF-alpha-induced PECAM-1 rise. The decrease in TNF-alpha-induced rise in ICAM-1 level was associated with a reduction of NF-kappaB activation, a reduction in mRNA expression of ICAM-1, and a functional reduction in monocyte adhesion to cultured endothelial cells. Niacin reduces CAM expression and monocyte adhesion to endothelial cells. Apart from its lipid-modifying effects, these pleiotropic effects of niacin may potentially contribute to the beneficial effects of risk reduction for atherosclerotic disease.

The proinflammatory phenotype of PECAM-1-deficient mice results in atherogenic diet-induced steatohepatitis

The severity of nonalcoholic steatohepatitis (NASH) is determined by environmental and genetic factors, the latter of which are incompletely characterized. Platelet endothelial cell adhesion molecule-1 (PECAM-1) is a 130-kDa transmembrane glycoprotein expressed on blood and vascular cells. In the present study, we provide data for the novel finding that genetic deficiency of PECAM-1 potentiates the development and progression of NASH. We found that the rate of development and severity of diet-induced NASH are markedly enhanced in PECAM-1-deficient [knockout (KO)] mice relative to wild-type (WT) mice, as measured by histological and biochemical evaluation. Livers from KO mice exhibited typical histological features of NASH, including macrovesicular fat accumulation, hepatocyte injury with infiltration of inflammatory cells, fibrosis, and heightened oxidative stress. Alanine aminotransferase, a marker for liver injury, was also significantly higher in KO compared with WT mice. Consistent with a role for PECAM-1 as a suppressor of proinflammatory cytokines, plasma levels of inflammatory cytokines, including TNF-alpha and monocyte chemoattractant protein-1 (MCP-1), were also significantly higher in KO compared with WT mice. These findings are the first to show that the PECAM-1-deficient mouse develops progressive nonalcoholic fatty liver disease (NAFLD), supporting a role for PECAM-1 as a negative regulator of NAFLD progression. Future examination of recently identified PECAM-1 allelic isoforms in humans as potential risk factors for developing NASH may be warranted.

The association of ICAM-1 Exon 6 (E469K) but not of ICAM-1 Exon 4 (G241R) and PECAM-1 Exon 3 (L125V) polymorphisms with the development of differentiation syndrome in acute promyelocytic leukemia

The use of all trans-retinoic acid (ATRA) is the basis of treatment of acute promyelocytic leukemia (APL) and represents the paradigm of differentiation therapy. In general, ATRA is well-tolerated but may be associated with a potentially lethal side-effect, referred to as retinoic acid or differentiation syndrome (DS). The cellular and molecular mechanisms of DS are poorly understood and involve changes in the adhesive qualities and cytokine secretion of leukemic cells during ATRA-induced differentiation. As leukocyte extravasation is a key event in DS pathogenesis, we analyzed the association between the polymorphisms at Exon 4 (G241R) and Exon 6 (E469K) of ICAM-1 and Exon 3 (L125V) of PECAM-1 genes with DS development in APL patients treated with ATRA and anthracyclines. DS was diagnosed in 23/127 (18.1%) APL patients at an average of 11.5 days after the start of ATRA. All patients presented respiratory distress associated with increased ground-glass opacity in chest radiographies. Other accompanying symptoms were: fever not attributable to infection (65.2%), generalized edema (37.5%), weight gain (37.5%), and impairment of renal function (8.6%). We detected an association between development of DS and the AA genotype at Codon 469 of ICAM-1 (odds ratio of 3.5; 95% confidence interval: 1.2-10.2). Conversely, no significant association was detected between G241R or L125V polymorphisms at Exon 4 of ICAM-1 and Exon 3 of PECAM-1, respectively. Our results suggest that susceptibility to DS in APL patients may be influenced by genetic variation in adhesion molecule loci.

Niacin affects cell adhesion molecules and plasminogen activator inhibitor-1 in HepG2 cells

BACKGROUND

Beyond lipid-modifying actions, niacin lowers the risk of atherothrombotic events by lowering prothrombotic factors like fibrinogen. Plasminogen activator inhibitor type 1 (PAI-1) is a potential factor for atherogenesis and thrombosis, increased in acute myocardial infarctions and restenosis after angioplasty. Cell adhesion molecules (CAM) mediate adhesion, recruitment and migration of white blood cells through vascular surfaces, an essential process in atherogenesis. ICAM-1 is a significant predictor of future coronary events. Whether niacin affects ICAM-1 expression is unknown. We studied the effects of niacin on PAI-1 and CAM using HepG2 cells.

METHODS

HepG2 cells were cultured in DMEM until 90% confluent. After serum starvation, cells were exposed to DME/F12 containing niacin. Transforming growth factor-beta (TGF-beta) was added directly to cell media. Cell lysate and conditioned media were collected for measurement of PAI-1 by ELISA. For measurement of ICAM, cells were treated with tumor necrosis factor-alpha (TNF-alpha) instead. The effect of niacin on mRNA expression of ICAM-1 was studied using RT-PCR.

RESULTS

Niacin reduced the TGF-beta-induced rise by 30% to 55% (p=0.002). The differences in degree of PAI-1 reduction, between different niacin concentrations, were not statistically significant. Niacin reduced TNF-alpha-induced rise in ICAM-1 levels by 66% to 89% (p<0.0001), but did not significantly affect TNF-alpha-induced rise in PECAM-1. Semiquantitative RT-PCR analysis showed that reduced TNF-alpha-induced rise in ICAM-1 mRNA expression significantly by 17% (p=0.001).

CONCLUSIONS

Treatment with niacin suppressed PAI-1 and ICAM-1 levels in HepG2 cells. Further studies to understand the mechanistic pathways of this suppression, could further explain benefits of niacin in prevention of atherosclerotic disease, and offer therapeutic avenues against the rising burden of atherothrombotic disease.

GATA2 is associated with familial early-onset coronary artery disease

The transcription factor GATA2 plays an essential role in the establishment and maintenance of adult hematopoiesis. It is expressed in hematopoietic stem cells, as well as the cells that make up the aortic vasculature, namely aortic endothelial cells and smooth muscle cells. We have shown that GATA2 expression is predictive of location within the thoracic aorta; location is suggested to be a surrogate for disease susceptibility. The GATA2 gene maps beneath the Chromosome 3q linkage peak from our family-based sample set (GENECARD) study of early-onset coronary artery disease. Given these observations, we investigated the relationship of several known and novel polymorphisms within GATA2 to coronary artery disease. We identified five single nucleotide polymorphisms that were significantly associated with early-onset coronary artery disease in GENECARD. These results were validated by identifying significant association of two of these single nucleotide polymorphisms in an independent case-control sample set that was phenotypically similar to the GENECARD families. These observations identify GATA2 as a novel susceptibility gene for coronary artery disease and suggest that the study of this transcription factor and its downstream targets may uncover a regulatory network important for coronary artery disease inheritance.

Coronary artery disease (CAD) is the most common form of heart disease in the Western world and is one of the leading causes of death in the United States. CAD is inherited and is a complex genetic disease because it results from changes to multiple genes acting in concert with one another and the environment. The authors locate CAD susceptibility genes by convergence of techniques and identify variation within a gene of interest in an early-onset CAD population. If a specific variant is found more often in affected individuals or families than in controls, this can suggest that this gene variant is associated with disease. The authors have identified a gene, GATA2, which is located in a genomic region suspected to contain genes for CAD and displays expression patterns predictive of location of disease within human donor aortas. They have identified several GATA2 variants that segregate with CAD in a family-based early-onset CAD population and have further validated two of these associations in a separate young case-control sample affected with CAD. These data imply that the transcription factor GATA2 may play a role in CAD susceptibility and suggest that the study of GATA2 targets may uncover a set of GATA2-regulated genes important to CAD inheritance.

The alleles of PECAM-1

Previous studies have reported the existence of eleven different single nucleotide polymorphisms (SNPs) within human PECAM-1 mRNA, several of which have recently been associated with disease. Though SNPs in the PECAM-1 gene have been known for some time, the genetic background on which they exist, and their association into distinct allelic isoforms has not yet been established. To identify the major allelic isoforms of PECAM-1, we determined the nucleotide sequence of individual full-length cloned cDNAs derived from anonymous, unrelated volunteer individuals. Initial sequence analysis of 34 alleles from 17 individuals confirmed the presence of two distinct human PECAM-1 alleles (L(98)S(536)R(643) and V(98)N(536)G(643)) within the human population. Each of these were found, upon more detailed analysis, to be superimposed on a previously unreported a2479g nucleotide polymorphism within the 3' untranslated region (3'UTR) that occurred on both allelic isoforms - yielding a total of four major alleles. Multiplex Luminex bead analysis of an additional 259 individuals allowed identification of 117 individuals homozygous for either the L(98)S(536) or V(98)N(536) allele, and sequence analysis around the R643G and a2479g polymorphic sites permitted accurate determination of significant differences in the gene frequencies of LSRa, LSRg, VNGa, and VNGg among Caucasian individuals. Identification of these PECAM-1 allelic isoforms should facilitate future detailed examination of PECAM-1-related disease associations, and may help resolve previously disparate results.