Genetic variants of TNFSF4 and risk for carotid artery disease and stroke

Omics-CNN: A comprehensive pipeline for predictive analytics in quantitative omics using one-dimensional convolutional neural networks

Background and objective

The development of machine learning-based models that can be used for the prediction of severe diseases has been one of the main concerns of the scientific community. The current study seeks to expand a highly sophisticated tool, the Convolutional Neural Networks, making it applicable in multidimensional omics data classification problems and testing the newly introduced method on publicly available transcriptomics and proteomics data.

Methods

In this study, we introduce Omics-CNN, a Convolutional Neural Network-based pipeline, which couples Convolutional Neural Networks with dimensionality reduction, preprocessing, clustering, and explainability techniques to make them suitable to build highly accurate and interpretable classification models from high-throughput omics data. The developed tool has the potential to classify patients depending on the expression of genetic and clinical factors and identify features that can act as diagnostic biomarkers. Regarding dimensionality reduction, univariate and multivariate techniques were explored and compared. Gradient Weighted Class Activation Mapping analysis was performed to determine the most important features in the classification of the samples after training the model.

Results

The newly introduced pipeline was applied to one transcriptomics and one proteomics dataset for the identification of diagnostic models and biosignatures for Ischemic Stroke (IS) and COVID-19 infection, reporting highly accurate biosignatures with accuracies of 96 % and 95.41 %, respectively. Meanwhile, classification models based solely on a small part of attributes provided lower predictive accuracy, but identified compact transcript biosignature (KRT15, VPRBP, TNFRSF4, GORASP2) for Ischemic Stroke and protein biosignature (ADGRB3, VNN2, AGER, CIAPIN1) for Covid-19 infection diagnosis, respectively.

Conclusions

Omics-CNN, overcame the inherent problems of applying Convolutional Neural Networks for the training diagnostic models with quantitative omics data, outperforming previous models of machine learning developed using the same datasets for Ischemic Stroke and Covid-19 infection diagnosis, determining the most contributing biomarkers for both diseases.

Genetic Risk Factors of Intracranial Atherosclerosis

PURPOSE OF REVIEW

Intracranial atherosclerosis (ICAS) is the most common cause of stroke throughout the world. It also increases the risk of recurrent stroke and dementia. As a complex and multifactorial disease, ICAS is influenced by multiple genetic, biological, and environmental factors. This review summarizes the candidate gene and genome-wide studies aimed at discovering genetic risk factors of ICAS.

RECENT FINDINGS

Numerous studies have focused on the association between single-nucleotide polymorphisms (SNPs) of atherosclerosis-related genes and the risk of ICAS. Variants in adiponectin Q (ADIPOQ), ring finger protein 213 (RNF213), apolipoprotein E (APOE), phosphodiesterase 4D (PDE4D), methylenetetrahydrofolate reductase (MTHFR), lipoprotein lipase (LPL), α-adducin (ADD1) genes, angiotensin-converting enzyme (ACE), and other genes related to renin-angiotensin-aldosterone system have been associated with ICAS. We review the available evidences on the candidate genes and SNPs associated with genetic susceptibility to ICAS, and point out future developments of this field. Genetic discoveries could have clinical implications for intracranial atherosclerotic disease.

The role of OX40L and ICAM-1 in the stability of coronary atherosclerotic plaques and their relationship with sudden coronary death

Background

Coronary heart disease is related to sudden death caused by multi-factors and a major threat to human health.This study explores the role of OX40L and ICAM-1 in the stability of coronary plaques and their relationship with sudden coronary death.

Methods

A total of 118 human coronary arteries with different degrees of atherosclerosis and/or sudden coronary death comprised the experimental group and 28 healthy subjects constituted the control group were isolated from patients. The experimental group was subdivided based on whether the cause of death was sudden coronary death and whether it was accompanied by thrombosis, plaque rupture, plaque outflow and other secondary changes: group I: patients with coronary atherosclerosis but not sudden coronary death, group II: sudden coronary death without any of the secondary changes mentioned above, group III: sudden coronary death with coronary artery atherosclerotic lesions accompanied by either of the above secondary changes. The histological structure of the coronary artery was observed under a light microscope after routine HE staining, and the related indexes of atherosclerotic plaque lesions were assessed by image analysis software. The expressions of OX40L and ICAM-1 were detected by real-time quantitative PCR (RT-PCR), immunohistochemistry (IHC) and Western blotting, and the correlations between the expressions and the stability of coronary atherosclerotic plaque and sudden coronary death were analyzed.

Results

(1) The expression of OX40L protein in the control group and the three experimental groups showed an increasing trend, and the difference between groups was statistically significant (P < 0.05). (2) The expression of the ICAM-1 protein in the control group and the three experimental groups showed a statistically significant (P < 0.05) increasing trend. (3) The expression of OX40L and ICAM-1 mRNAs increased in the control and the three experimental groups and the difference was statistically significant (P < 0.05).

Conclusion

The expression of OX40L and ICAM-1 proteins and mRNAs is positively correlated with the stability of coronary atherosclerotic plaque and sudden coronary death.

Lack of association of tumor necrosis factor superfamily member 4 (TNFSF4) gene polymorphisms (rs3850641 and rs17568) with coronary heart disease and stroke: A systematic review and meta-analysis

Objective:

To evaluate the association between the tumor necrosis factor superfamily member 4 (TNFSF4) gene polymorphisms and common cardiovascular and cerebrovascular diseases.

Methods:

A literature-based search was conducted through databases including PubMed, EMBASE, Cochrane Library, CNKI, and WanFang data. Crude odds ratios (ORs) and 95% confidence intervals (CI) were calculated to estimate the strength of the association between TNFSF4 polymorphisms (rs3850641 and rs17568) and the risk of coronary heart disease (CHD) and stroke.

Results:

Overall, 11 eligible studies were included in this meta-analysis. G allele was showed not to be associated with CHD and stroke, compared with A allele (rs3850641: OR=1.02, 95% CI=0.89–1.17; rs17568: OR=1.09, 95% CI=0.89–1.33). Genotypic analysis demonstrated that there was no significant association between the risk of CHD and stroke and rs3850641 [homozygous comparison (GG vs. AA): OR=1.05, 95% CI=0.74–1.50; heterozygous comparison (GA vs. AA): OR=1.00, 95% CI=0.88–1.13; recessive model (GG vs. GA+AA): OR=1.04, 95% CI=0.76–1.43; dominant model (GG+GA vs. AA): OR=1.01, 95% CI=0.88–1.17]. Similarly, no susceptibility between CHD and stroke and rs17568 polymorphism was uncovered (GG vs. AA: OR=1.04, 95% CI=0.74–1.46; GA vs. AA: OR=1.07, 95% CI=0.62–1.83; GG+GA vs. AA: OR=1.13, 95% CI=0.82–1.56; GG vs. GA+AA: OR=1.01, 95% CI=0.74–1.39).

Conclusion:

The present study demonstrated that there is no significant relationship between TNFSF4 gene polymorphism and cerebrovascular and cardiovascular diseases.

rs1234313 and rs45454293 are risk factors of cerebral arterial thrombosis, large artery atherosclerosis, and carotid plaque in the Han Chinese population: a case-control study

Background

Ischemic stroke is a leading cause of mortality and morbidity worldwide. Stenosis or blockage of an artery from atherosclerosis can cause insufficient cerebral blood supply, which leads to ischemic stroke. It has been reported that the polymorphisms of TNFSF4 (tumor necrosis factor super family member 4) are associated with multiple autoimmune diseases. However, it is still unclear whether TNFSF4 gene polymorphisms are associated with ischemic stroke in the Han Chinese population. Here we analyzed the association between TNFSF4 single nucleotide polymorphisms (SNPs) and cerebral arterial thrombosis in the Han Chinese population.

Method

We consecutively recruited 481 patients with cerebral arterial thrombosis and 538 healthy controls. Neck ultrasonography and magnetic resonance imaging (MRI) were used to evaluate large artery atherosclerosis (LAA) and small vessel disease (SVD), as well as the thickness and calcification of carotid artery. DNA was purified from the peripheral blood samples. TNFSF4 SNPs, rs1234313 and rs45454293, were genotyped using PCR.

Results

rs1234313 SNP had a significant correlation with the LAA and SVD subtypes in allelic (G vs A), dominate (GG/GA vs AA) and genotypic (GA vs AA; GG vs AA) models, as well as with the calcification of carotid plaque in dominant (GG/GA vs AA, p = 0.022) and genotypic (GA vs AA, p = 0.01) models. rs45454293 SNP had a significant correlation with the LAA and SVD subtypes in allelic (G vs A) and genotypic models, as well as with the thick carotid plaque in allelic (G vs A, p = 0.01) model.

Conclusion

TNFSF4 SNPs, rs1234313 and rs45454293, are associated with the risk of specific subtypes of cerebral arterial thrombosis in the Han Chinese population.

2016 Jeffrey M. Hoeg Award Lecture

Innate and adaptive immune effector mechanisms, in conjunction with hyperlipidemia, are important drivers of atherosclerosis. The interaction between the different immune cells and the secretion of cytokines and chemokines determine the progression of atherosclerosis. The activation or dampening of the immune response is tightly controlled by immune checkpoints. Costimulatory and coinhibitory immune checkpoints represent potential targets for immune modulatory therapies for atherosclerosis. This review will discuss the current knowledge on immune checkpoints in atherosclerosis and the clinical potential of immune checkpoint targeted therapy for atherosclerosis.

Immune checkpoint proteins: exploring their therapeutic potential to regulate atherosclerosis

The immune system provides a large variety of immune checkpoint proteins, which involve both costimulatory and inhibitory proteins. Costimulatory proteins can promote cell survival, cell cycle progression and differentiation to effector and memory cells, whereas inhibitory proteins terminate these processes to halt ongoing inflammation. Immune checkpoint proteins play a pivotal role in atherosclerosis by regulating the activation and proliferation of various immune and non-immune cells, such as T-cells, macrophages and platelets. Upon activation within the atherosclerotic lesions or in secondary lymphoid organs, these cells produce large amounts of pro-atherogenic cytokines that contribute to the growth and destabilization of lesions, which can result in rupture of the lesion causing acute coronary syndromes, such as a myocardial infarction. Given the presence and regulatory capacity of immune checkpoint proteins in the circulation and atherosclerotic lesions of cardiovascular patients, modulation of these proteins by, for example, the use of monoclonal antibodies, offers unique opportunities to regulate pro-inflammatory immune responses in atherosclerosis. In this review, we highlight the latest advances on the role of immune checkpoint proteins, such as OX40-OX40L, CTLA-4 and TIM proteins, in atherosclerosis and discuss their therapeutic potential as promising immunotherapies to treat or prevent cardiovascular disease.

LINKED ARTICLES

This article is part of a themed section on Targeting Inflammation to Reduce Cardiovascular Disease Risk. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.22/issuetoc and http://onlinelibrary.wiley.com/doi/10.1111/bcp.v82.4/issuetoc.

ATVB Distinguished Scientist Award: How Costimulatory and Coinhibitory Pathways Shape Atherosclerosis

OBJECTIVE

Immune cells play a critical role in atherosclerosis. Costimulatory and coinhibitory molecules of the tumor necrosis factor receptor and CD28 immunoglobulin superfamilies not only shape T-cell and B-cell responses but also have a major effect on antigen-presenting cells and nonimmune cells.

APPROACH AND RESULTS

Pharmacological inhibition or activation of costimulatory and coinhibitory molecules and genetic deletion demonstrated their involvement in atherosclerosis. This review highlights recent advances in understanding how costimulatory and coinhibitory pathways shape the immune response in atherosclerosis.

CONCLUSIONS

Insights gained from costimulatory and coinhibitory molecule function in atherosclerosis may inform future therapeutic approaches.

OX40 regulates pressure overload-induced cardiac hypertrophy and remodelling via CD4+ T-cells

OX40, which belongs to the tumour necrosis factor (TNF)-receptor family, is a costimulatory receptor that can potentiate T-cell receptor signalling on the surface of T-lymphocytes. The role of OX40 in non-immune systems, particularly the cardiovascular system, has not been defined. In the present study, we observed a noticeable increase in OX40 expression during cardiac remodelling in rodent heart. In the present study, cardiac hypertrophy was induced by aortic banding (AB) in OX40 knockout (KO) mice and wild-type (WT) mice. After 8 weeks, the OX40 KO mice showed significantly attenuated cardiac hypertrophy, fibrosis and inflammation as well as preserved cardiac function compared with the WT mice. Follow-up in vitro studies suggested that CD4⁺ T-lymphocyte proliferation and pro-inflammatory cytokine release were significantly decreased, whereas anti-inflammatory cytokine release was considerably increased in OX40 KO mice compared with WT mice as assessed by Cell Counting Kit-8 (CCK-8) assay and ELISA. Co-culturing neonatal rat cardiomyocytes with the activated supernatant of CD4⁺ T-lymphocytes from OX40 KO mice reduced the hypertrophy response. Interestingly, OX40 KO mice with reconstituted CD4⁺ T-lymphocytes presented deteriorated cardiac remodelling. Collectively, our data indicate that OX40 regulates cardiac remodelling via the modulation of CD4⁺ T-lymphocytes.

Gene expression signatures, pathways and networks in carotid atherosclerosis

BACKGROUND

Embolism from unstable atheromas in the carotid bifurcation is a major cause of stroke. Here, we analysed gene expression in endarterectomies from patients with symptomatic (S) and asymptomatic (AS) carotid stenosis to identify pathways linked to plaque instability.

METHODS

Microarrays were prepared from plaques (n = 127) and peripheral blood samples (n = 96) of S and AS patients. Gene set enrichment, pathway mapping and network analyses of differentially expressed genes were performed.

RESULTS

These studies revealed upregulation of haemoglobin metabolism (P = 2.20E-05) and bone resorption (P = 9.63E-04) in S patients. Analysis of subgroups of patients indicated enrichment of calcification and osteoblast differentiation in S patients on statins, as well as inflammation and apoptosis in plaques removed >1 month compared to <2 weeks after symptom. By prediction profiling, a panel of 30 genes, mostly transcription factors, discriminated between plaques from S versus AS patients with 78% accuracy. By meta-analysis, common gene networks associated with atherosclerosis mapped to hypoxia, chemokines, calcification, actin cytoskeleton and extracellular matrix. A set of dysregulated genes (LMOD1, SYNPO2, PLIN2 and PPBP) previously not described in atherosclerosis were identified from microarrays and validated by quantitative PCR and immunohistochemistry.

CONCLUSIONS

Our findings confirmed a central role for inflammation and proteases in plaque instability, and highlighted haemoglobin metabolism and bone resorption as important pathways. Subgroup analysis suggested prolonged inflammation following the symptoms of plaque instability and calcification as a possible stabilizing mechanism by statins. In addition, transcriptional regulation may play an important role in the determination of plaque phenotype. The results from this study will serve as a basis for further exploration of molecular signatures in carotid atherosclerosis.

Targeting the adaptive immune system: new strategies in the treatment of atherosclerosis

Atherosclerosis is a lipid-driven chronic inflammatory disease of the arterial wall. Current treatment of atherosclerosis is focused on limiting its risk factors, such as hyperlipidemia or hypertension. However, treatments that target the inflammatory nature of atherosclerosis are still under development. Discovery of novel targets involved in the inflammation of the arterial wall creates opportunities to design new therapeutics that successfully modulate atherosclerosis. Here, we review drug targets that have proven to play pivotal roles in the adaptive immune system in atherosclerosis, and we discuss their potential as novel therapeutics.

The collagen cross-linking enzyme lysyl oxidase is associated with the healing of human atherosclerotic lesions

BACKGROUND

Acute clinical complications of atherosclerosis such as myocardial infarction (MI) and ischaemic stroke are usually caused by thrombus formation on the ruptured plaque surface. Collagen, the main structural protein of the fibrous cap, provides mechanical strength to the atherosclerotic plaque. The integrity of the fibrous cap depends on collagen fibre cross-linking, a process controlled by the enzyme lysyl oxidase (LOX).

METHODS AND RESULTS

We studied atherosclerotic plaques from human carotid endarterectomies. LOX was strongly expressed in atherosclerotic lesions and detected in the regions with ongoing fibrogenesis. Higher LOX levels were associated with a more stable phenotype of the plaque. In the studied population, LOX mRNA levels in carotid plaques predicted the risk for future MI. Within the lesion, LOX mRNA levels correlated positively with levels of osteoprotegerin (OPG) and negatively with markers of immune activation. The amount of LOX-mediated collagen cross-links in plaques correlated positively also with serum levels of OPG.

CONCLUSIONS

Lysyl oxidase may contribute to the healing of atherosclerotic lesions and to the prevention of its lethal complications. Mediators of inflammation may control LOX expression in plaques and hence plaque stability.

Human genetic evidence for involvement of CD137 in atherosclerosis

Atherosclerosis is an inflammatory disease and the main cause of cardiovascular disease. Inflammation promotes plaque instability and clinical disease, such as myocardial infarction, stroke and peripheral vascular disease. Subclinical atherosclerosis begins with thickening of the arterial intimal layer, and increased intima-media thickness (IMT) in the carotid artery is a widely used measurement of subclinical atherosclerosis. Activation of CD137 (tumor necrosis factor receptor super family 9) promotes inflammation and disease development in murine atherosclerosis. CD137 is expressed in human atherosclerosis, but its role is largely unknown. This study uses a genetic approach to investigate CD137 in human atherosclerotic disease. In publicly available data on genotype and gene expression from the HapMap project, the minor T allele of rs2453021, a single nucleotide polymorphism in CD137, was significantly associated with CD137 gene expression. In the PROCARDIS and Wellcome Trust Case Control Consortium (WTCCC) cohorts of 13,029 cases and controls, no significant association was detected between the minor T allele of rs2453021 and risk for coronary artery disease or myocardial infarction. However, in the IMPROVE multicenter study of 3,418 individuals, the minor T allele of rs2453021 was associated with increased IMT of the common carotid artery (CCA), as measured by ultrasonography, with presence of plaque in CCA and with increased incidence of adverse noncardiac vascular events. Taken together, this study shows that the minor T allele of rs2453021 is associated with increased IMT in the CCA and increased risk of incident noncardiac vascular events, thus providing the first human genetic evidence for involvement of CD137 in atherosclerosis.

TNFSF4 gene polymorphism rs3861950 but not rs3850641 is associated with the risk of cerebral infarction in a Chinese population

Tumor necrosis factor superfamily member 4 (TNFSF4) plays a key role in the process of atherosclerosis, a common risk factor for both myocardial and cerebral infarctions. Recent studies indicate that the single nucleotide polymorphism (SNP) rs3850641 in TNFSF4 is associated with higher risk of myocardial infarction, but little is known about the association between TNFSF4 variation and cerebral infarction (CI). A case-control study involving 385 CI patients and 385 age-matched, sex-matched non-CI controls was conducted in a Chinese population, only the most common subtype, atherosclerosis CI, was recruited. Two SNPs of TNFSF4, rs3850641 and rs3861950, were genotyped by the TaqMan SNP genotyping method, and verified partly by genomic DNA sequencing. The results revealed a significant allelic association between rs3861950 and CI (Odds ration = 1.733, 95 % confidence interval = 1.333-2.254, P = 0.000). Genotypic association analysis demonstrated that the CC genotype of rs3861950 confers susceptibility to CI (Odds ration = 2.896, 95 % confidence interval = 1.368-6.132), and it was associated with a significantly higher risk of ischemic stroke (Odds ration = 3.520, 95 % confidence interval = 1.546-8.015, P = 0.003) after adjusting for the other confirmed risk factors such as the history of hypertension, diabetes, CAD, smoking and alcohol drinking. While the odds ratio of the T allele to the C allele was 1.733 (95 % confidence interval: 1.333-2.254). However, there was no significant association between rs3850641 and CI (Odds ration = 1.288, 95 % confidence interval = 0.993-1.670, P = 0.056). TNFSF4 gene polymorphism rs3861950, but not rs3850641, is associated with the risk of atherosclerosis CI in a Chinese population.

Absence of association between atherosclerotic cerebral infarction and TNFSF4/TNFRSF4 single nucleotide polymorphisms rs1234313, rs1234314 and rs17568 in a Chinese population

OBJECTIVE

To clarify the association between atherosclerotic cerebral infarction (ACI) and the single nucleotide polymorphisms (SNP) rs1234313 and rs1234314 (in TNFSF4) and rs17568 (in TNFRSF4).

METHODS

Genomic DNA was extracted from peripheral blood of patients with ACI and healthy control subjects. The presence of carotid plaque was determined. Rs1234313, rs1234314 and rs17568 were characterized via SNP genotyping assay and verified by DNA sequencing.

RESULTS

Genotype distributions were in Hardy-Weinberg equilibrium. There were no significant differences in the allele and genotype distributions of rs1234313, rs1234314 and rs17568 between patients with ACI (n = 450) and healthy control subjects (n = 378), or between patients with ACI and carotid plaque (n = 342) and controls.

CONCLUSIONS

There were no significant associations between rs1234313, rs1234314 and rs17568 and ACI risk in a Han Chinese population.

Expression of retinoic acid target genes in coronary artery disease

Coronary atherosclerosis can lead to myocardial infarction, and secondarily to post-infarct remodelling and heart failure. Retinoic acid (RA) influences cell proliferation. We hypothesized that RA could influence gene expression and proliferation of cardiovascular cells. Left ventricular biopsies from patients with end-stage heart failure due to coronary artery disease (CAD) or dilated cardiomyopathy were investigated for the content of RA metabolites using liquid chromatography mass spectrometry (LC-MS/MS), and compared with healthy donors. All-trans retinoic acid (ATRA) was increased in the hearts of CAD patients. Gene expression (quantitative PCR) of RA target genes was not influenced in failing hearts, but was increased in the hearts of patients with CAD undergoing open heart surgery. The expression of RA target genes was increased in atherosclerotic lesions from carotid arteries compared to healthy arteries. Stimulation of cardiomyocytes, cardiofibroblasts, smooth muscle cells and endothelial cells with ATRA increased the gene expression of the key enzymes. Cardiofibroblast and smooth muscle cell proliferation were reduced by ATRA, which increased endothelial cell proliferation. Coronary artery disease leads to increased expression of RA target genes. ATRA accumulated in the failing human heart. All investigated cell types present in the heart had induced expression of RA target genes when stimulated with ATRA, which also influenced cell proliferation.

Toll-Like Receptor 7 Protects From Atherosclerosis by Constraining “Inflammatory” Macrophage Activation

Background

Toll-like receptors (TLRs) have long been considered to be major culprits in the development of atherosclerosis, contributing both to its progression and clinical complications. However, evidence for most TLRs beyond TLR2 and TLR4 is lacking.

Methods and Results

We used experimental mouse models, human atheroma cultures, and well-established human biobanks to investigate the role of TLR7 in atherosclerosis. We report the unexpected finding that TLR7, a receptor recognizing self–nucleic acid complexes, is protective in atherosclerosis. In Apoe −/− mice, functional inactivation of TLR7 resulted in accelerated lesion development, increased stenosis, and enhanced plaque vulnerability as revealed by Doppler ultrasound and/or histopathology. Mechanistically, TLR7 interfered with macrophage proinflammatory responses to TLR2 and TLR4 ligands, reduced monocyte chemoattractant protein-1 production, and prevented expansion of Ly6C hi inflammatory monocytes and accumulation of inflammatory M1 macrophages into developing atherosclerotic lesions. In human carotid endarterectomy specimens TLR7 levels were consistently associated with an M2 anti-inflammatory macrophage signature (interleukin [IL]-10, IL-1RA, CD163, scavenger and C-type lectin receptors) and collagen genes, whereas they were inversely related or unrelated to proinflammatory mediators (IL-12/IL-23, interferon beta, interferon gamma, CD40L) and platelet markers. Moreover, in human atheroma cultures, TLR7 activation selectively suppressed the production of key proatherogenic factors such as monocyte chemoattractant protein-1 and tumor necrosis factor without affecting IL-10.

Conclusions

These findings provide evidence for a beneficial role of TLR7 in atherosclerosis by constraining inflammatory macrophage activation and cytokine production. This challenges the prevailing concept that all TLRs are pathogenic and supports the exploitation of the TLR7 pathway for therapy.

Altered expression of TNFSF4 and TRAF2 mRNAs in peripheral blood mononuclear cells in patients with systemic lupus erythematosus: association with atherosclerotic symptoms and lupus nephritis

OBJECTIVES

This study compares the expression levels of tumor necrosis factor ligand superfamily member 4 (TNFSF4) and TNF-R-associated factor 2 (TRAF2) mRNAs in peripheral blood mononuclear cells (PBMCs) of patients with systemic lupus erythematosus (SLE) against healthy controls. The association of SLE disease activity index (SLEDAI) and clinical features of SLE with altered expression levels of TNFSF4 and TRAF2 mRNAs were also evaluated.

DESIGN

We used real-time reverse transcription polymerase chain reaction to measure TNFSF4 and TRAF2 mRNAs expression levels in peripheral blood mononuclear cells of 57 SLE patients and 57 healthy controls.

RESULTS

The expression level of TNFSF4 mRNA was significantly higher in SLE patients than in the control group. Overexpression of TNFSF4 was correlated with arthritis, atherosclerosis and lupus nephritis. TRAF2 mRNA was underexpressed in PBMCs of SLE patients, and its lower expression was associated with atherosclerosis and lupus nephritis. The altered expression levels of TNFSF4 and TRAF2 mRNAs was significantly correlated with SLEDAI.

CONCLUSION

Our results suggest that changes in the expression levels of TNFSF4 and TRAF2 mRNAs may significantly correlate with the pathogenesis of SLE, the disease activity and different clinical features of lupus, particularly lupus nephritis, atherosclerosis and arthritis.

Cloning and functional studies of a splice variant of CYP26B1 expressed in vascular cells

Background

All-trans retinoic acid (atRA) plays an essential role in the regulation of gene expression, cell growth and differentiation and is also important for normal cardiovascular development but may in turn be involved in cardiovascular diseases, i.e. atherosclerosis and restenosis. The cellular atRA levels are under strict control involving several cytochromes P450 isoforms (CYPs). CYP26 may be the most important regulator of atRA catabolism in vascular cells. The present study describes the molecular cloning, characterization and function of atRA-induced expression of a spliced variant of the CYP26B1 gene.

Methodology/Principal Findings

The coding region of the spliced CYP26B1 lacking exon 2 was amplified from cDNA synthesized from atRA-treated human aortic smooth muscle cells and sequenced. Both the spliced variant and full length CYP26B1 was found to be expressed in cultured human endothelial and smooth muscle cells, and in normal and atherosclerotic vessel. atRA induced both variants of CYP26B1 in cultured vascular cells. Furthermore, the levels of spliced mRNA transcript were 4.5 times higher in the atherosclerotic lesion compared to normal arteries and the expression in the lesions was increased 20-fold upon atRA treatment. The spliced CYP26B1 still has the capability to degrade atRA, but at an initial rate one-third that of the corresponding full length enzyme. Transfection of COS-1 and THP-1 cells with the CYP26B1 spliced variant indicated either an increase or a decrease in the catabolism of atRA, probably depending on the expression of other atRA catabolizing enzymes in the cells.

Conclusions/Significance

Vascular cells express the spliced variant of CYP26B1 lacking exon 2 and it is also increased in atherosclerotic lesions. The spliced variant displays a slower and reduced degradation of atRA as compared to the full-length enzyme. Further studies are needed, however, to clarify the substrate specificity and role of the CYP26B1 splice variant in health and disease.

A CYP26B1 polymorphism enhances retinoic acid catabolism and may aggravate atherosclerosis

All-trans retinoic acid, controlled by cytochrome P450, family 26 (CYP26) enzymes, potentially has beneficial effects in atherosclerosis treatment. This study investigates CYP26 subfamily B, polypeptide 1 (CYP26B1) in atherosclerosis and the effects of a genetic polymorphism in CYP26B1 on retinoid catabolism. We found that CYP26B1 mRNA was induced by retinoic acid in human atherosclerotic arteries, and CYP26B1 and the macrophage marker CD68 were colocalized in human atherosclerotic lesions. In mice, Cyp26B1 mRNA was higher in atherosclerotic arteries than in normal arteries. Databases were queried for nonsynonymous CYP26B1 single nucleotide polymorphisms (SNPs) and rs2241057 selected for further studies. Constructs of the CYP26B1 variants were created and used for production of purified proteins and transfection of macrophagelike cells. The minor variant catabolized retinoic acid with significantly higher efficiency, indicating that rs2241057 is functional and suggesting reduced retinoid availability in tissues with the minor variant. rs2241057 was investigated in a Stockholm Coronary Atherosclerosis Risk Factor (SCARF) subgroup. The minor allele was associated with slightly larger lesions, as determined by angiography. In summary, this study identifies the first CYP26B1 polymorphism that alters CYP26B1 capacity to metabolize retinoic acid. CYP26B1 was expressed in macrophage-rich areas of human atherosclerotic lesions, induced by retinoic acid and increased in murine atherosclerosis. Taken together, the results indicate that CYP26B1 capacity is genetically regulated and suggest that local CYP26B1 activity may influence atherosclerosis.

T cell costimulatory and coinhibitory pathways in vascular inflammatory diseases

A broad array of evidence indicates that T lymphocytes make significant contributions to vascular inflammation in the setting of atherosclerotic disease, hypertension, autoimmune vasculitis, and other disorders. Experimental data show that costimulatory and coinhibitory pathways involving molecules of the B7-CD28 and TNF–TNFR families regulate T cell responses that promote vascular disease. Antigen presenting cells (APCs) display both peptide–major histocompatibility complex antigen and costimulators or coinhibitors to T cells. Two major types of APCs, dendritic cells (DCs) and macrophages, are present in significant numbers in the walls of arteries affected by atherosclerosis and arteritis, and some DCs are present in normal arteries. Costimulatory and coinhibitory molecules expressed by these vascular APCs can contribute to the activation or inhibition of effector T cells within the arterial wall. Vascular DCs may also be involved in transport of antigens to secondary lymphoid organs, where they activate or tolerize naïve T cells, depending on the balance of costimulators and coinhibitors they express. Costimulatory blockade is already an approved therapeutic approach to treat autoimmune disease and prevent transplant rejection. Preclinical models suggest that costimulatory blockade may also be effective in treating vascular disease. Experiential data in mice show that DCs pulsed with the appropriate antigens and treated in a way that reduces costimulatory capacity can reduce atherosclerotic disease, presumably by inducing T cell tolerance. Progress in treating vascular disease by immune modulation will require a more complete understanding of the functions of different costimulatory and coinhibitory pathways and the different subsets of vascular APCs involved.

Serotonin reuptake inhibitor antidepressants (SSRIs) against atherosclerosis

Selective serotonin reuptake inhibitors (SSRIs) are a class of drug widely used for treatment of mood disorders, including depression and cardiovascular disease. A search for related articles in the PubMed database was attempted. It covered studies, reports, reviews and editorials of the last 5 years.

Pro-inflammatory cytokines, such as TNF-α, IL-1 and IL-6, stimulate central serotonin (5-HT) neurotransmission and are over-expressed in depression, which has been linked with hypothalamic-pituitary-adrenal axis (HPA) hyperactivity. They have also been implicated in the pathogenesis and progression of other stress-induced disorders, like myocardial infarction (MI) and coronary heart disease (CHD), as they seem to modulate cardiovascular function by a variety of mechanisms. Biological mechanisms like these may explain the link between depression and CHD. There are a variety of environmental factors as well as genetic factors that might influence the pharmacogenetics of antidepressant drugs. New generation selective serotonin reuptake inhibitor antidepressants (SSRIs) causing a reduced cardiovascular morbidity and mortality may be related to serotonin platelet abnormalities in depressed patients that are effectively treated by SSRIs. SSRIs such as fluoxetine, paroxetine, sertraline and citalopram are not only considered to be free from the cardiotoxicity of their predecessors but also to function as safe and efficacious agents against depression, platelet activation, atherosclerosis and development and prognosis of coronary heart disease. However, there is a need for more studies in order to establish the exact biochemical mechanisms that are responsible for these diseases and the immunoregulatory effects of chronic use of SSRI medications.

The role of costimulatory receptors of the tumour necrosis factor receptor family in atherosclerosis

Atherosclerosis is a chronic inflammatory disease that is mediated by both the innate and adaptive immune responses. T lymphocytes, that together with B cells are the cellular effectors of the adaptive immune system, are currently endowed with crucial roles in the development and progression of atherosclerosis. Costimulatory receptors are a class of molecules expressed by T lymphocytes that regulate the activation of T cells and the generation of effector T-cell responses. In this review we present the roles of costimulatory receptors of the tumour necrosis factor receptor (TNFR) superfamily in atherosclerosis and discuss the implications for future therapies that could be used to specifically modulate the immune response of pathogenic T cells in this disease.

The utility of collaborative biobanks for cardiovascular research

Differences between animal and human atherosclerosis have led to the requirement for clinical data, imaging information and biological material from large numbers of patients and healthy persons. Where such "biobanks" exist, they have been fruitful sources for genomewide association, diagnostic accuracy, ethnicity, and risk stratification cohort studies. In addition once established, they attract funding for future projects. Biobanks require a network of medical contributors, secure storage facilities, bioinformatics expertise, database managers, and ethical working practices to function optimally. There is the opportunity for collaboration between individual biobanks to further amplify the advantages afforded.

[Association study between TNFSF4 and coronary heart disease]

Previous studies suggest that TNFSF4 is a susceptibility gene of atherosclerosis. But case-control association analysis in Swedish population and German population provided inconsistent, even opposite results. In order to explore the relationship between this gene and coronary heart disease (CHD) in Chinese Han population, we collected 498 cases and 509 controls from Qilu hospital of Shandong University and analyzed the association between five single-nucleotide polymorphisms (SNPs) (rs1234314, rs45454293, rs3850641, rs1234313, and rs3861950) of TNFSF4 and CHD. On the basis of using traditional statistical analysis methods based on single SNP and haplotypes, we introduced principal component score-based logistic regression analysis to deal with the data. The results suggested that in Armitage trend test, only rs3861950 was significant, when used the Bonferroni correction, and all of the five SNPs were not statistically significant. In the logistic regression analysis which adjusts the confounding factors, all of the five SNPs were not statistically significant. In haplotype analysis, the frequencies of six haplotypes were significantly different in cases and controls (CTAGT (P=0.0006), CTAAC (P=0.0123), CCAGT (P=0.0004), GTGGT (P=0.0329), GCGAC (P<0.0001), and GCAAC (P=0.0173)). In principal component score-based logistic regression analysis, the first principal component has statistical significance (P=0.0236). These results indicate that TNFSF4 is a susceptibility gene of CHD in Chinese Han population.

Lack of evidence to support the association of polymorphisms within the TNFSF4 gene and coronary heart disease in a Chinese Han population

Coronary heart disease (CHD) is a complex disorder resulting from the interaction of a number of genetic and environmental factors. Increasing evidence has shown that OX40 ligand (OX40L), also known as tumor necrosis factor superfamily member 4 (TNFSF4), plays a key role in the pathogenesis of atherosclerosis. However, there have been inconsistent reports in various populations, and further studies are required to clarify this issue. A gene-based association study was conducted using five single-nucleotide polymorphisms (SNPs) reported in previous studies. The five SNPs (rs1234314, rs45454293, rs3850641, rs1234313 and rs3861950) were genotyped in 547 unrelated CHD patients and 601 healthy controls in a case-control study using polymerase chain reaction and restriction fragment length polymorphism. rs1234314, rs3850641 and rs3861950 were further genotyped in an additional 512 cases and 520 controls using the TaqMan SNP genotyping method. A possible relationship between the five SNPs and the severity of CHD was investigated. The results revealed no significant association between the TNFSF4 polymorphism and CHD. In addition, the stratified analysis of genotypic and allelic frequencies showed no association between the TNFSF4 polymorphism and CHD in either gender. Finally, no significant correlation between the TNFSF4 polymorphism and CHD severity was detected. These findings do not support a role of the TNFSF4 gene in CHD pathogenesis in the Chinese Han population.

Cardiovascular disease complications in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a highly variable autoimmune disease characterized by aberrant host-immune responses and chronic inflammation. Recently, a strong association between cardiovascular (CV) disease and SLE has emerged. Thus, low serum, high-density lipoprotein strongly correlated with elevated erythrocyte sedimentation rate, IL-6, TNF-alpha and the SLE disease activity index after adjusting for age, gender, race, BMI, insulin sensitivity and any concurrent drug use. In SLE, CV disease is characterized by increased VEGF, which may alter vascular hemostasis and promote neoangiogenesis. Increased low-density lipoprotein-cholesterol and proinflammatory high-density lipoprotein-cholesterol uptake by monocytes together with enhanced low-density lipoprotein-cholesterol oxidation results in the deposition of altered cholesterol forms into the vascular wall. This contributes to precocious and accelerated development of coronary artery plaques. Cholesterol-reducing drugs should be considered in the standard of care of SLE patients, especially in those with an unfavorable CV disease risk profile, which could reduce the probability of atherosclerosis progressing to CV disease or stroke in these patients.

Endogenous control genes in complex vascular tissue samples

BACKGROUND

Gene expression microarrays and real-time PCR are common methods used to measure mRNA levels. Each method has a fundamentally different approach of normalization between samples. Relative quantification of gene expression using real-time PCR is often done using the 2(/\)(-DeltaDeltaCt) method, in which the normalization is performed using one or more endogenous control genes. The choice of endogenous control gene is often arbitrary or bound by tradition. We here present an analysis of the differences in expression results obtained with microarray and real-time PCR, dependent on different choices of endogenous control genes.

RESULTS

In complex tissue, microarray data and real-time PCR data show the best correlation when endogenous control genes are omitted and the normalization is done relative to total RNA mass, as measured before reverse transcription.

CONCLUSION

We have found that for real-time PCR in heterogeneous tissue samples, it may be a better choice to normalize real-time PCR Ct values to the carefully measured mass of total RNA than to use endogenous control genes. We base this conclusion on the fact that total RNA mass normalization of real-time PCR data shows better correlation to microarray data. Because microarray data use a different normalization approach based on a larger part of the transcriptome, we conclude that omitting endogenous control genes will give measurements more in accordance with actual concentrations.

Association of TNFSF4 (OX40L) polymorphisms with susceptibility to systemic sclerosis

Objective

It is increasingly being appreciated that multiple autoimmune diseases share common susceptibility genes. The tumour necrosis factor ligand superfamily member 4 gene (TNFSF4, OX40L), which encodes for the T cell costimulatory molecule OX40 ligand, has been identified as a susceptibility gene for the development of systemic lupus erythematosus (SLE). Accordingly, the aim of the current study was to investigate the possible association of the TNFSF4 gene region with systemic sclerosis (SSc), an autoimmune disease that leads to the development of cutaneous and visceral fibrosis.

Methods

A total of 9 single nucleotide polymorphisms (SNPs) in the TNFSF4 gene region, previously associated with susceptibility to SLE, were tested for association with SSc in a collection of 1059 patients with SSc and 698 controls.

Results

Case-control comparisons revealed a significant association between susceptibility to SSc and the minor alleles at SNPs rs1234314 (OR 1.20, 95% CI 1.04 to 1.4, p_FDR=0.019), rs2205960 (OR 1.24, 95% CI 1.10 to 1.50, p_FDR=0.019) and rs844648 (OR 1.16, 95% CI 1.01 to 1.30, p_FDR=0.032). The minor allele at rs844644 was protective (OR 0.84, 95% CI 0.70 to 0.97, p_FDR=0.038). Analysis of subsets of patients with SSc demonstrated significant associations of the TNFSF4 SNPs with limited and diffuse SSc as well as specific SNPs that were associated with SSc-associated autoantibodies. Finally, the analyses suggest a potential interaction between two TNFSF4 SNPs, rs2205960 and rs844648, with regards to SSc susceptibility.

Conclusions

Polymorphisms in the TNFSF4 gene region are associated with susceptibility to SSc and its clinical and autoantibody subsets. TNFSF4 may be another gene that confers risk to multiple autoimmune diseases.

Adaptive immunity and atherosclerosis

Atherosclerosis involves the formation of inflammatory arterial lesions and is one of the most common causes of death globally. It has been evident for more than 20 years that adaptive immunity and T cells in particular regulate the magnitude of the atherogenic pro-inflammatory response. T cells also influence the stability of the atherosclerotic lesion and thus the propensity for thrombus formation and the clinical outcome of disease. This review summarizes our current understanding of T cells in atherogenesis, including which antigens they recognize, the role of T cell costimulation/coinhibition, and their secretion of pro- and anti-inflammatory mediators. Furthermore, we outline future areas of research and potential clinical intervention strategies.