Association analysis of IL-12B and IL-23R polymorphisms in myocardial infarction

Polymorphism of IL-12/IL-23 axis is associated with coronary heart disease

IL12B encodes the shared p40 subunit (IL-12p40) of IL-12 and IL-23, which have diverse immune functions and are closely related to the occurrence and development of atherosclerosis (AS). However, the exact role of IL12B in coronary heart disease (CHD) was still unknown. A case-control association analysis was performed between five single nucleotide polymorphisms (SNPs) of IL12B (rs1003199, rs3212219, rs2569254, rs2853694 and rs3212227) and CHD in Chinese Han population (1824 patients with CHD vs. 2784 controls). Logistic regression analyses were used to study the relationships between SNPs and CHD, while multiple linear regression analyses were used to test the association between the SNP and the severity of CHD. In addition, the plasma IL12B concentration of CHD patients were detected by ELISA. We detected a significant association between one of the SNPs, rs2853694-G and CHD (padj  = 2.075 × 10-5 , OR, 0.773 [95% CI, 0.686-0.870]). Stratified analysis showed that rs2853694 was associated with CHD in both male and female populations and was significantly associated with both early- and late-onset CHD. In addition, rs2853694 is also related to the different types of CHD including clinical-CHD and anatomical-CHD. Moreover, there are significant differences in serum IL12B concentrations between rs2853694-TT carriers and rs2853694-GT carriers in CHD patients (p = 0.010). A common variant of IL12B was found significantly associated with CHD and its subgroups. As a shared subunit of IL-12 and IL-23, IL-12p40 may play a key role in IL-12/IL-23 axis mediated AS, which is expected to be an effective therapeutic target for CHD.

Gene polymorphism in IL17A and gene-gene interaction in the IL23R/IL17A axis are associated with susceptibility to coronary artery disease

AIMS

Studies have confirmed that the IL-23R/IL-17A axis plays an important role in the development of autoimmune and inflammatory diseases. However, its role in coronary artery disease (CAD) remains unclear. Here, we conducted a large sample case-control study to investigate the association between the IL23R/IL17A axis and CAD in the Chinese Han population.

METHODS

Two SNPs, rs2275913: G>A (IL17A) and rs6682925: T>C (IL23R), were genotyped in 3042 CAD cases and 3216 controls using the high-resolution melt technology (HRM). Logistic regression analyses were used to adjust the traditional risk factors for CAD and perform the gene interaction analyses. Multiple linear regression analyses were used to study the relationships between the selected SNPs and the levels of serum lipids. In addition, meta-analysis also was performed for the association between rs6682925 and rs2275913 with CAD in different popolations.

RESULTS

Our case-control and meta-analysis for single SNPs demonstrated that the frequencies of the alleles and the distribution of the genotypes had no significant differences in CAD cases compared with controls. In the stratified analysis, we observed that the frequency of the IL17A rs2275913-A allele was more epidemic in early-onset CAD than in the controls (P_adj = 0.005, OR = 1.209, 95% CI: 1.059-1.382), and the minor allele C of rs6682925 was associated with a decreased level of serum total cholesterol under a recessive model (P_adj = 0.011). We demonstrated a significant interaction between rs6682925 and rs2275913 and CAD in the Chinese Han population. Four genotypes (CTGG, CCAA, CCAG, CCGG) were significantly associated with CAD (P_adj = 2.94 × 10^-4, OR = 0.619, 95% CI: 0.478-0.803; P_adj = 0.01, OR = 1.808, 95% CI: 1.152-1.869; P_adj = 6 × 10^-6, OR = 2.179, 95% CI: 1.558-3.049; P_adj = 0.001, OR = 1.883, 95% CI: 1.282-2.762, respectively).

CONCLUSION

Our study found no single SNP of rs2275913 in IL17A and rs6682925 in IL23R was associated with CAD in the Chinese population, but the interaction of them were significantly associated with CAD susceptibility, highlighting the key role of the IL-23R/IL-17A axis in the development of CAD. In addition, we also found rs2275913 was associated with early-onset CAD and rs6682925 was associated with total cholesterol levels, which will contribute to the clinical stratified management of this common disease.

IL-12B Polymorphisms Are Associated with the Presence of Premature Coronary Artery Disease and with Cardiovascular Risk Factors: The Genetics of Atherosclerotic Disease Mexican Study

The aim of this study was to evaluate the association of the IL-12B polymorphisms with the presence of premature coronary artery disease (pCAD) and with cardiovascular risk factors. The study included 2163 individuals (1133 patients with pCAD and 1030 healthy controls). Seven IL-12B polymorphisms (rs1363670, rs3212220, rs3212227, rs6887695, rs1433048, rs2853694, and rs1368439) were determined by TaqMan assays. The associations were evaluated by logistic regression using inheritance models adjusted for confounding variables. The rs1363670 was associated with a low risk of pCAD (odds ratio [OR] 0.718, p_dominant = 0.034; OR 0.701, p_heterozygote = 0.024; OR 0.702, p_codominant1 = 0.025). The association of the polymorphisms with cardiovascular risk factors was evaluated independently in each group. In controls, the rs3212227, rs3212220, and rs6887695 polymorphisms were associated with subcutaneous abdominal fat > p75, whereas the rs6887695 was associated with a high risk of central obesity. In pCAD patients, the rs2853694 was associated with a low risk of insulin resistance; and association of rs3212227 and rs3212220 with a low risk of metabolic syndrome was found, and the rs6887695 polymorphism was nominally associated with a high risk of hyperuricemia. In conclusion, the IL-12B rs1363670 polymorphism was associated with a low risk of pCAD, and in both pCAD patients and healthy controls, some IL-12B polymorphisms were associated with cardiovascular risk factors.

The impact of interleukin 12B (1188A>C), interleukin 16 (-295T>C), and interleukin 18 (607C>A, 137G>C) gene polymorphisms on long-term renal transplant function and recipient outcomes

BACKGROUND

Inflammatory mediators play an important role in kidney graft outcome. The cytokine and chemokine gene polymorphisms are associated with variable production, activity, expression, or ligand-receptor affinity. Genetic variation in the DNA sequence of the interleukin 12B (IL12B), interleukin 16 (IL16), and interleukin 18 (IL18) genes may lead to altered cytokine production and activity. These variations can lead to changes in individual patient outcomes after kidney transplantation. It is known that polymorphisms of interleukins have an influence on inflammatory diseases, eg, Crohn's disease, diabetes, and asthma.

AIM

The aim of this study was to evaluate the correlation between IL12B, IL16, and IL18 gene polymorphisms with delayed graft function (DGF), acute rejection episodes (AR), and chronic rejection episodes (CR).

MATERIALS AND METHODS

A total of 267 (38.6% women, 61.4% men) recipients were included in the study. Cadaveric kidney transplantations were performed at the Department of General Surgery and Transplantation. Polymerase chain reaction was used to determine gene polymorphisms of IL12B (rs3212227), IL16 (4778889), and IL18 (rs1946518, rs187238) in 2 mL of serum. Statistical significance (P < .05) was analyzed by logit regression, ANOVA and odds ratio (OR) of χ(2) with Yates correction (95% confidence interval).

RESULTS

Regression analysis revealed no significance between AR/DGF/CR and IL-2B, IL16, IL18rs1946518, and IL18-rs187238 (P > .05). The CR group, AA vs CC genotype of IL18 (rs1946518), had an OR = 2.35 (P = .04). AR and DGF groups had no significance in OR.

CONCLUSIONS

There was no statistical significance between IL12B, IL16, and IL18 (rs187238) gene polymorphisms and kidney graft outcome after transplantation. Presence of AA genotype (IL18-rs1946518) is connected with a 2.35 times higher risk of CR occurrence.

Analysis of the association between IL-23R rs11209026 polymorphism and incidence of atherosclerosis

Th17/IL-23 axis is an important pro-inflammatory pathway in atherosclerosis. IL-23 receptor (IL-23R) pathway has an important role in T-helper cells 17 (Th17) differentiation and survival. We compared normal subjects and patients with atherosclerosis in terms of the R381Q variant of the IL-23R gene as a functional single-nucleotide polymorphism (SNP). This case-control study recruited 200 patients who presented with cardiovascular symptoms to Afshar Hospital, Yazd, Iran. The participants were allocated to five groups based on angiographic results. The severity of the disease was determined according to the numbers of involved vessels. Patients with normal coronary arteries, minimal coronary artery involvement, one involved vessel, two involved vessels and three-vessel disease were allocated to groups I-V, respectively. DNA was extracted from whole blood samples by the salting-out method. Genotyping was performed by polymerase chain reaction followed by restriction fragment length polymorphism assay and multinomial logistic regression for analyses The presence of SNP A>G rs11209026 of IL-23 receptor gene was significantly associated with disease severity (P = 0.008). The frequencies of the heterozygous (AG) genotype in the control group and subjects with minimal involvement, and patients with one-, two-, and three-vessel disease were 22.5%, 12.5%, 10%, 10.24% and 4.8%, respectively. Our results indicated an association between the rs11209026 G>A polymorphism of the IL-23 receptor gene and the risk of atherosclerosis. This genetic variant may in fact cause protection against atherosclerosis progression. However, further studies on gene polymorphism and cell expression are required to clarify the mechanisms involved in the pathogenesis of atherosclerosis.

Genetic variation and coronary atherosclerosis in patients with systemic lupus erythematosus

Coronary artery disease is the major cause of mortality in patients with systemic lupus erythematosus (SLE). Increased cardiovascular risk in SLE is not explained by traditional risk factors. We examined the hypothesis that genetic variation contributes to the presence of coronary atherosclerosis in patients with SLE. The genotypes of single-nucleotide polymorphisms (SNP) in 152 candidate genes linked with autoimmune or cardiovascular risk were determined in 125 patients with SLE. Coronary artery calcium (CAC), a measure of coronary atherosclerosis, was detected in 32 patients (26%) by electron-beam computed tomography. Polymorphism in 20 of the candidate genes (ADAM33, ADIPOQ, CCL5, CCR7, CDKN2B, CSF1, IL4, IL12A, IL23R, INS, IRF5, MIF, MS4A1, PTGS1, PTPN22, RETN, SELE, TNFSF4, TNFRSF11B, and VCAM1) were nominally associated with the presence of CAC (p-values = 0.001-0.047 after adjustment for age, sex and race). Some of these are known susceptibility genes for SLE and others have been implicated in cardiovascular disease in other populations. No association withstood false discovery rate adjustment. Replication studies in additional cohorts of patients with SLE may be informative.

Immunological profile of silent brain infarction and lacunar stroke

Neuroinflammation is believed to be involved in the pathophysiological mechanisms of silent brain infarcts (SBI). However, the immunological profile of SBI has been scarcely investigated. In the context of a national research project named SILENCE, aimed at investigating clinical, biochemical and pathogenic features of SBI, we have measured the plasma profile of some inflammatory-related molecules in SBI patients (n = 21), patients with recent lacunar infarcts (LI, n = 28) and healthy controls (n = 31), consecutively enrolled in four Italian centres. A panel of chemokines (MIG, CTACK, IL16, SDF1a, MCP1), growth factors (SCF, SCGFb, HGF, IL3), immunoglobulin-type adhesion molecules (ICAM1, VCAM1), proinflammatory cytokines (IL18, INFa2, MIF, IL12p40), cell surface receptors on T-cells (IL2Ra), and inductors of apoptosis (TRAIL) was assessed in plasma samples by Luminex xMAP™ technology. Immunological parameters were compared using non-parametric statistics and performance to distinguish SBI and LI was evaluated by receiver operating characteristic (ROC) analysis. Plasma levels of ICAM1 were significantly higher in both SBI and LI patients as compared to controls (SBI≥LI>Ctrl). A different trend was observed for IL16 (SBI<LI>Ctrl), SCF (LI<SBI>Ctrl) and SCGFb (SBI>LI<Ctrl). SBI subjects had significantly increased levels of MIG when compared to controls (LI≤SBI>Ctrl) and IL18 when compared to LI patients (Ctrl≤SBI>LI). All the other immunological markers did not significantly differ among groups. According to ROC analysis, the best predictor for SBI condition was the chemokine MIG (AUC = 0.84, sensitivity 86%, specificity 77%), while SCF had the best performance in distinguishing LI patients (AUC = 0.84, sensitivity 86%, specificity 68%). These results confirm the involvement of inflammatory processes in cerebrovascular disorders, particularly in SBI, a very common age-related condition. The differences in plasma profile of inflammatory molecules may underlie different pathological mechanisms in SBI and LI patients.

Gene-gene interaction and functional impact of polymorphisms on innate immune genes in controlling Plasmodium falciparum blood infection level

Genetic variations in toll-like receptors and cytokine genes of the innate immune pathways have been implicated in controlling parasite growth and the pathogenesis of Plasmodium falciparum mediated malaria. We previously published genetic association of TLR4 non-synonymous and TNF-α promoter polymorphisms with P.falciparum blood infection level and here we extend the study considerably by (i) investigating genetic dependence of parasite-load on interleukin-12B polymorphisms, (ii) reconstructing gene-gene interactions among candidate TLRs and cytokine loci, (iii) exploring genetic and functional impact of epistatic models and (iv) providing mechanistic insights into functionality of disease-associated regulatory polymorphisms. Our data revealed that carriage of AA (P = 0.0001) and AC (P = 0.01) genotypes of IL12B 3′UTR polymorphism was associated with a significant increase of mean log-parasitemia relative to rare homozygous genotype CC. Presence of IL12B+1188 polymorphism in five of six multifactor models reinforced its strong genetic impact on malaria phenotype. Elevation of genetic risk in two-component models compared to the corresponding single locus and reduction of IL12B (2.2 fold) and lymphotoxin-α (1.7 fold) expressions in patients'peripheral-blood-mononuclear-cells under TLR4Thr399Ile risk genotype background substantiated the role of Multifactor Dimensionality Reduction derived models. Marked reduction of promoter activity of TNF-α risk haplotype (C-C-G-G) compared to wild-type haplotype (T-C-G-G) with (84%) and without (78%) LPS stimulation and the loss of binding of transcription factors detected in-silico supported a causal role of TNF-1031. Significantly lower expression of IL12B+1188 AA (5 fold) and AC (9 fold) genotypes compared to CC and under-representation (P = 0.0048) of allele A in transcripts of patients' PBMCs suggested an Allele-Expression-Imbalance. Allele (A+1188C) dependent differential stability (2 fold) of IL12B-transcripts upon actinomycin-D treatment and observed structural modulation (P = 0.013) of RNA-ensemble were the plausible explanations for AEI. In conclusion, our data provides functional support to the hypothesis that de-regulated receptor-cytokine axis of innate immune pathway influences blood infection level in P. falciparum malaria.

IL23R and IL12B SNPs and Haplotypes Strongly Associate with Crohn's Disease Risk in a New Zealand Population

DNA samples from 339 Crohn's disease (CD) and 407 randomly selected controls from the Auckland (New Zealand) IBD project, were genotyped for five common single nucleotide polymorphisms in IL-23R (rs11805303, rs7517847, rs1343151, rs11209026, and rs10889677) and two in IL-12B (rs1363670 and rs6887695). While the IL-12B variants did not show an overall association and other IL23R variants led to minor changes in the risk of CD, rs1343151 and/or rs7517847 variants in the IL-23R gene strongly reduced the risk of developing CD at both allelic and genotype levels. A significantly decreased risk of first diagnosis of childhood CD was observed in individuals carrying the A allele of rs1343151, or between 17–40 y in individuals carrying the G allele in rs7517847 of IL-23R. A significantly decreased risk of ileocolonic or structuring disease was observed in individuals carrying the A allele in either rs11209026 or rs1343151, or the G allele in rs7517847 of IL-23R, and when such individuals did develop the disease, they were unlikely to require a bowel resection. Certain haplotypes very strongly modified risk. There was evidence for interactions of IL-23R variants with the NOD2 wild-type (d/d) genotype. Down-regulating the function of the IL-23R gene may decrease CD risk in the normal population.

Interleukin-17: friend or foe in atherosclerosis?

PURPOSE OF REVIEW

To summarize the current knowledge on the origin and physiological function of T helper 17 (Th17) and discuss the contrasting results pertaining to the role of Th17 and interleukin-17 (IL-17) in atherosclerosis.

RECENT FINDINGS

Atherosclerosis is a chronic inflammatory arterial disease driven by both innate and adaptive immune responses to modified lipoproteins. Although initial studies have focused on the role of Th1 and Th2 responses in atherosclerosis, more recent findings identified atheroprotective roles for several subsets of regulatory T cells. Th17 represents a new T-cell lineage with important roles in the clearance of pathogenic bacteria and fungi. The increase of Th17 and IL-17 has been recently linked to the pathogenesis of several autoimmune diseases. However, its role in chronic inflammatory diseases such as atherosclerosis remains poorly understood. The few studies available on this topic have generated contrasting results, which could be attributed to different approaches used on various mouse models.

SUMMARY

IL-17 seems to have a modulatory role in atherosclerosis. Future studies are needed to better determine the molecular mechanisms involved in this regulation and examine whether targeting IL-17 pathway will be useful to treat cardiovascular diseases.