Lack of association between lymphotoxin-alpha, galectin-2 polymorphisms and coronary artery disease: a meta-analysis

Identification of 5 hub genes for diagnosis of coronary artery disease

Background

Coronary artery disease (CAD) is a main cause leading to increasing mortality of cardiovascular disease (CVD) worldwide. We aimed to discover marker genes and develop a diagnostic model for CAD.

Methods

CAD-related target genes were searched from DisGeNET. Count expression data and clinical information were screened from the GSE202626 dataset. edgeR package identified differentially expressed genes (DEGs). Using online STRING tool and Cytoscape, protein-protein reactions (PPI) were predicted. WebGestaltR package was employed to functional enrichment analysis. We used Metascape to conduct module-based network analysis. VarElect algorithm provided genes-phenotype correlation analysis. Immune infiltration was assessed by ESTIMATE package and ssGSEA analysis. mRNAsi was determined by one class logistic regression (OCLR). A diagnostic model was constructed by SVM algorithm.

Results

162 target genes were screened by intersection 1,714 DEGs and 1,708 CAD related target genes. 137 target genes of the 162 target genes were obtained using PPI analysis, in which those targets were enriched in inflammatory cytokine pathways, such as chemokine signaling pathway, and IL-17 signaling pathway. From the above 137 target genes, four functional modules (MCODE1-4) were extracted. From the 162 potential targets, CAD phenotype were directly and indirectly associated with 161 genes and 22 genes, respectively. Finally, 5 hub genes (CCL2, PTGS2, NLRP3, VEGFA, LTA) were screened by intersections with the top 20, directly and indirectly, and genes in MCODE1. PTGS2, NLRP3 and VEGFA were positively, while LTA was negatively correlated with immune cells scores. PTGS2, NLRP3 and VEGFA were negatively, while LTA was positively correlated with mRNAsi. A diagnostic model was successfully established, evidenced by 92.59% sensitivity and AUC was 0.9230 in the GSE202625 dataset and 94.11% sensitivity and AUC was 0.9706 in GSE120774 dataset.

Conclusion

In this work, we identified 5 hub genes, which may be associated with CAD development.

Galectin-2 in Health and Diseases

Galectin-2 is a prototype member of the galactoside-binding galectin family. It is predominately expressed in the gastrointestinal tract but is also detected in several other tissues such as the placenta and in the cardiovascular system. Galectin-2 expression and secretion by epithelial cells has been reported to contribute to the strength of the mucus layer, protect the integrity of epithelia. A number of studies have also suggested the involvement of galectin-2 in tissue inflammation, immune response and cell apoptosis. Alteration of galectin-2 expression occurs in inflammatory bowel disease, coronary artery diseases, rheumatoid arthritis, cancer, and pregnancy disorders and has been shown to be involved in disease pathogenesis. This review discusses our current understanding of the role and actions of galectin-2 in regulation of these pathophysiological conditions.

Galectins for Diagnosis and Prognostic Assessment of Human Diseases: An Overview of Meta-Analyses

An increasing number of studies have explored the activities and functions of galectins. However, translation of these researches into clinical practice seems to be lacking. As compared to scattered individual studies, meta-analyses can provide a more comprehensive review of current evidence and reach a more unbiased and powered conclusion by synthesizing data from diverse studies. In this paper, findings from meta-analyses were reviewed to establish the role of galectins in diagnosis and prognostic assessment of various human diseases. First, in patients with cancer, galectin-1 expression is often associated with poorer survival, but galectin-9 expression is associated with better survival. Galectin-3 is a diagnostic biomarker for thyroid cancer and a predictor of worse survival in patients with colorectal cancer and improved survival in patients with gastric cancer. Second, galectin-3 is useful for diagnosis and prognostic assessment of heart failure and prediction of atrial fibrillation and its recurrence. Third, in chronic kidney disease, galectin-3 is valuable for predicting poor survival. Fourth, during pregnancy, galectin-13 is potentially helpful for identifying patients who do not have preeclampsia.

Galectin-1 as an Emerging Mediator of Cardiovascular Inflammation: Mechanisms and Therapeutic Opportunities

Galectin-1 (Gal-1), an evolutionarily conserved β-galactoside-binding lectin, controls immune cell homeostasis and tempers acute and chronic inflammation by blunting proinflammatory cytokine synthesis, engaging T-cell apoptotic programs, promoting expansion of T regulatory (Treg) cells, and deactivating antigen-presenting cells. In addition, this lectin promotes angiogenesis by co-opting the vascular endothelial growth factor receptor (VEGFR) 2 signaling pathway. Since a coordinated network of immunomodulatory and proangiogenic mediators controls cardiac homeostasis, this lectin has been proposed to play a key hierarchical role in cardiac pathophysiology via glycan-dependent regulation of inflammatory responses. Here, we discuss the emerging roles of Gal-1 in cardiovascular diseases including acute myocardial infarction, heart failure, Chagas cardiomyopathy, pulmonary hypertension, and ischemic stroke, highlighting underlying anti-inflammatory mechanisms and therapeutic opportunities. Whereas Gal-1 administration emerges as a potential novel treatment option in acute myocardial infarction and ischemic stroke, Gal-1 blockade may contribute to attenuate pulmonary arterial hypertension.

Genetic association of pro-inflammatory cytokine gene polymorphisms with coronary artery disease (CAD) in a North Indian population

BACKGROUND

Cytokines regulate the expression of inflammatory molecules which destabilize the atheromatic plaques. This study focuses on studying the association of inflammatory cytokine polymorphisms like TNF-α -308 (G/A), TNF-β +252 (A/G), IL-6 -174 (G/C) and IL-6 -597 (G/A), and IFN-ɣ +874 (T/A) with coronary artery disease (CAD) among north Indian patients.

MATERIALS AND METHODS

143 CAD and 137 normal healthy controls were recruited in this study. DNA extraction was carried out by high salting out method. TNF-α -308 (G/A) (rs1800797), TNF-β +252 (A/G) (rs909253), IL-6 -174 (G/C) (rs1800795), IL6 -597 (G/A) (rs1800797), and IFN-ɣ +874 (T/A) (rs2430561) SNPs were genotyped by TaqMan®SNP genotyping assays. Different statistical analyses were performed using SPSS v 22.0 and SNPStats. p≤0.05 was considered significant.

RESULTS

Significant risk association with CAD was found for TNF-α -308 (G/A) "A" allele (OR=5.6, CI 1.8-17.4, p=0.001) and TNF-β +252 (A/G) "G" allele (OR=3.4, CI=1.9-6.0, p<0.001). However, no statistical significance was found for IL-6 -174 (G/C) or IL6 -597 (G/A), with CAD. TNF-α -308 (G/A), and TNF-β +252 (A/G) haplotype "GG" "AG" increased CAD risk significantly (GG haplotype, adjusted OR=2.6, CI 1.4-5.0, p=0.003 and AG haplotype OR=8.5, CI 2.2-33.35, p=0.002) after adjustments for age, sex, TC, TG, HDL, APOB, smoking and diet.

DISCUSSION

The present study found significant risk association for TNF-α -308 (G/A), and TNF-β +252 (A/G) genotypes, alleles and haplotypes, with CAD in a North Indian population.

Deletion of P2Y2 receptor reveals a role for lymphotoxin-α in fatty streak formation

Background

Lymphotoxin alpha (LTα) is expressed in human atherosclerotic lesions and genetic variations in the LTα pathway have been linked to myocardial infarction. Activation of the P2Y₂ nucleotide receptor (P2Y₂R) regulates the production of LTα. in vitro. We aimed to uncover a potential pathway linking purinergic receptor to LTα-mediated inflammatory processes pivotal to the early stages of atherosclerosis in apolipoprotein E (ApoE^−/−) deficient mice.

Methods and results

En face immunostaining revealed that P2Y₂R and VCAM-1 are preferentially expressed in the atherosclerosis prone site of the mouse aortic sinus. Deletion of the P2Y₂R gene suppresses VCAM-1 expression. Compared with ApoE^−/−mice, ApoE^−/−mice lacking the P2Y₂R gene (ApoE^−/−/P2Y₂R^−/−) did not develop fatty streak lesions when fed a standard chow diet for 15 weeks. Systemic and CD4⁺ T cell production of the pro-inflammatory cytokine lymphotoxin-alpha (LTα) were specifically inhibited in ApoE^−/−/P2Y₂R^−/− mice. Anti-LTα preventive treatment was initiated in ApoE^−/− mice with intraperitoneal administration of recombinant human tumor necrosis factor receptor 1 fusion protein (TNFR1-Fc) on 5 consecutive days before the disease onset. Remarkably, none of the TNFR1:Fc-treated ApoE^−/− mice exhibited atherosclerotic lesions at any developmental stage.

Significance

ApoE^−/− mice deficient in P2Y₂R exhibit low endothelial cell VCAM-1 levels, decreased production of LTα and delayed onset of atherosclerosis. These data suggest that targeting this nucleotide receptor could be an effective therapeutic approach in atherosclerosis.

Patients with chronic three-vessel disease in a 15-year follow-up study: genetic and non-genetic predictors of survival

Genetic and non-genetic predictors of 15-year survival in patients with chronic three-vessel disease (3VD) were investigated. Coronary angiography was performed on 810 subjects with symptoms of stable ischemic heart disease in 1998. The patients with 3VD were genotyped for 23 candidate polymorphisms covering the PPAR-RXR pathway, matrix metalloproteinase-2, renin-angiotensin-aldosterone system, endothelin-1, cytokine genes, MTHFR and APO E variants. Fifteen-year survival data were obtained from the national insurance registry. All data were available in the case of 150 patients with 3VD. Statistical analysis used stepwise Cox regression with dominant, recessive, or additive mode of genetic expression. Involved variables included age, sex, BMI, blood pressure, diabetes, ejection fraction, left main stenosis, previously diagnosed coronary stenosis, myocardial infarction in personal history, and coronary bypass along with polymorphisms pre-selected by log-rank tests. Out of the 23 polymorphisms, four were included in the model construction. SNP in the IL-6 gene rs1800795 (-174 G/C) has been found to be a significant predictor of survival. This SNP was in a linkage disequilibrium with rs1800797 (-597 G/A) in the same gene (D'=1.0), which was also found to constitute a significant predictor of survival when rs1800795 was not included in the model construction. Age, increased BMI, diabetes, low EF, and left main stenosis were also significant predictors in all models. Age, increased BMI, diabetes, low ejection fraction, left main stenosis, and genetic variation in the IL-6 promoter were established as significant independent risk factors for the survival of patients with three-vessel disease.

Association between LGALS2 3279C>T and coronary artery disease: A case-control study and a meta-analysis

Coronary artery disease (CAD) has become the main cause of mortality worldwide. Lectin galactoside-binding soluble-2 (LGALS2) is involved in the cytokine lymphotoxin-α (LTA) cascade that may influence the progress of CAD. The aim of the present study was to assess the association between the LGALS2 3279C>T (rs7291467) polymorphism and CAD. A total of 562 cases and 572 controls were recruited to examine the association. A systematic meta-analysis was performed to evaluate the contribution of LGALS2 3279C>T polymorphism to the risk of CAD among 12,093 cases and 11,020 controls. There was no significant association found in the present case-control study. However, the meta-analysis showed that LGALS2 3279C>T played a protective role in CAD [P=0.008, odds ratio (OR), 0.90; 95% confidence interval (95% CI), 0.82-0.97] and particularly in the Asian population (P=0.006; OR, 0.82; 95% CI, 0.71-0.94). The present case-control study did not find a significant association between LGALS2 3279C>T and CAD in the Eastern Han Chinese population. However, the meta-analysis indicated that LGALS2 3279C>T played a protective role in CAD, suggesting an ethnic difference in the association of the locus with CAD.

The involvement of multiple thrombogenic and atherogenic markers in premature coronary artery disease

OBJECTIVE

To examine the association of atherogenic and thrombogenic markers and lymphotoxin-alfa gene mutations with the risk of premature coronary disease.

METHODS

This cross-sectional, case-control, age-adjusted study was conducted in 336 patients with premature coronary disease (<50 years old) and 189 healthy controls. The control subjects had normal clinical, resting, and exercise stress electrocardiographic assessments. The coronary disease group patients had either angiographically documented disease (>50% luminal reduction) or a previous myocardial infarction. The laboratory data evaluated included thrombogenic factors (fibrinogen, protein C, protein S, and antithrombin III), atherogenic factors (glucose and lipid profiles, lipoprotein(a), and apolipoproteins AI and B), and lymphotoxin-alfa mutations. Genetic variability of lymphotoxin-alfa was determined by polymerase chain reaction analysis.

RESULTS

Coronary disease patients exhibited lower concentrations of HDL-cholesterol and higher levels of glucose, lipoprotein(a), and protein S. The frequencies of AA, AG, and GG lymphotoxin-alfa mutation genotypes were 55.0%, 37.6%, and 7.4% for controls and 42.7%, 46.0%, and 11.3% for coronary disease patients (p = 0.02), respectively. Smoking, dyslipidemia, family history, and lipoprotein(a) and lymphotoxin-alfa mutations in men were independent variables associated with coronary disease. The area under the curve (C-statistic) increased from 0.779 to 0.802 (p<0.05) with the inclusion of lipoprotein(a) and lymphotoxin-alfa mutations in the set of conventional risk factors.

CONCLUSIONS

The inclusion of lipoprotein(a) and lymphotoxin-alfa mutations in the set of conventional risk factors showed an additive but small increase in the risk prediction of premature coronary disease.

Polymorphisms of LTA, LGALS2, and PSMA6 genes and coronary atherosclerosis: a pathological study of 1503 consecutive autopsy cases

OBJECTIVE

Recent genome-wide association studies have identified polymorphisms of lymphotoxin-α (LTA), galectin-2 (LGALS2), and proteasome subunit a type 6 (PSMA6) genes as genetic risk factors for myocardial infarction (MI). However, their effects on coronary atherosclerosis, an intermediate phenotype of MI, remain largely unknown.

METHODS

We investigated the correlation between polymorphisms of the LTA, LGALS2, and PSMA6 genes and the severity of pathological coronary stenosis index (CSI) and MI in 1503 consecutive autopsy cases of Japanese elderly patients.

RESULTS

The polymorphisms LTA rs1041981 and LGALS2 rs7291467 were associated with CSI with odds ratios of 1.54 (95% CI, 1.17-2.01; AA+CA over CC) and 1.62 (95% CI, 1.11-2.37; TT over CC+CT), respectively. PSMA6 rs1048990 was not associated with CSI. None of the SNPs was associated with MI in our sample.

CONCLUSION

Our findings indicate that the LTA and LGALS2 polymorphisms affect the subclinical phenotype of the coronary artery, which predisposes to the incidence of MI.

Genome-wide association study of coronary artery disease in the Japanese

A new understanding of the genetic basis of coronary artery disease (CAD) has recently emerged from genome-wide association (GWA) studies of common single-nucleotide polymorphisms (SNPs), thus far performed mostly in European-descent populations. To identify novel susceptibility gene variants for CAD and confirm those previously identified mostly in populations of European descent, a multistage GWA study was performed in the Japanese. In the discovery phase, we first genotyped 806 cases and 1337 controls with 451 382 SNP markers and subsequently assessed 34 selected SNPs with direct genotyping (541 additional cases) and in silico comparison (964 healthy controls). In the replication phase, involving 3052 cases and 6335 controls, 12 SNPs were tested; CAD association was replicated and/or verified for 4 (of 12) SNPs from 3 loci: near BRAP and ALDH2 on 12q24 (P=1.6 × 10(-34)), HLA-DQB1 on 6p21 (P=4.7 × 10(-7)), and CDKN2A/B on 9p21 (P=6.1 × 10(-16)). On 12q24, we identified the strongest association signal with the strength of association substantially pronounced for a subgroup of myocardial infarction cases (P=1.4 × 10(-40)). On 6p21, an HLA allele, DQB1(*)0604, could show one of the most prominent association signals in an ∼8-Mb interval that encompasses the LTA gene, where an association with myocardial infarction had been reported in another Japanese study. CAD association was also identified at CDKN2A/B, as previously reported in different populations of European descent and Asians. Thus, three loci confirmed in the Japanese GWA study highlight the likely presence of risk alleles with two types of genetic effects - population specific and common - on susceptibility to CAD.

Haplotype-based association of four lymphotoxin-alpha gene polymorphisms with the risk of coronary artery disease in Han Chinese

Lymphotoxin-alpha (LTA), a pro-inflammatory cytokine, has been implicated in the pathogenesis of coronary atherosclerosis. Meanwhile, association of some single nucleotide polymorphisms (SNPs) of LTA gene with coronary artery disease (CAD) has been evaluated; however, the results are irreproducible. We therefore investigated the relationship between four SNPs of LTA gene and CAD in Han Chinese: G+10A (rs1800683, 5'-untranslated region), A+80C (rs2239704, 5'-untranslated region), T+496C (Cys13Arg, rs2229094, exon 2), and C+804A (Thr26Asn, rs1041981, exon 3). Genotyping was performed in 438 CAD patients and 330 healthy controls. Single-locus analysis showed that the genotype and allele frequencies of G+10A polymorphism exhibited marginal differences between CAD patients and controls, although no statistical significance was observed after the Bonferroni correction. Logistic regression analysis revealed that GG genotype of G+10A polymorphism was significantly associated with the risk of CAD under the dominant mode, whereas no significant association was detected between A+80C polymorphism and CAD. In contrast, individuals carrying TT or TC genotype of T+496C polymorphism showed a decreased CAD risk relative to those with CC genotype under the recessive mode. Likewise, CC genotype of C+804A polymorphism was associated with a protective effect on CAD under the dominant mode. Further, in haplotype analysis, the haplotype G-C-T-C (in order of rs1800683, rs2239704, rs2229094 and rs1041981) was significantly associated with a decreased risk of CAD after assigning the most common haplotype A-C-T-A as a reference. In conclusion, we show a protective effect of the haplotype G-C-T-C on the occurrence of CAD, suggesting the involvement of LTA in CAD pathogenesis.