Differential contribution of IL-1Ra isoforms to allele-specific IL-1Ra mRNA accumulation

Interleukin-1 receptor antagonist: a promising cytokine against human squamous cell carcinomas

Inflammation, especially chronic inflammation, is closely linked to tumor development. As essential chronic inflammatory cytokines, the interleukin family plays a key role in inflammatory infections and malignancies. The interleukin-1 (IL-1) receptor antagonist (IL1RA), as a naturally occurring receptor antagonist, is the first discovered and can compete with IL-1 in binding to the receptor. Recent studies have revealed the association of the polymorphisms in IL1RA with an increased risk of squamous cell carcinomas (SCCs), including squamous cell carcinoma of the head and neck (SCCHN), cervical squamous cell carcinoma, cutaneous squamous cell carcinoma (cSCC), esophageal squamous cell carcinoma (ESCC), and bronchus squamous cell carcinoma. Here, we reviewed the antitumor potential of IL1RA as an IL-1-targeted inhibitor.

Interleukin 1 receptor antagonist (IL1RN) gene variants predict radiographic severity of knee osteoarthritis and risk of incident disease

OBJECTIVE

In these studies, we examined the association of single nucleotide polymorphisms (SNPs) of the IL1RN gene with radiographic severity of symptomatic knee osteoarthritis (SKOA) and the risk of incident OA. We also explored these genetic polymorphisms in patients with new onset rheumatoid arthritis (RA).

METHODS

Over 1000 subjects who met American College of Rheumatology criteria for tibiofemoral OA were selected from three independent, National Institute of Health (NIH)-funded cohorts. CTA and TTG haplotypes formed from three SNPs of the IL1RN gene (rs419598, rs315952, rs9005) were assessed for association with radiographic severity, and risk for incident radiographic OA (rOA) in a nested case-control cohort. These IL1RN haplotypes were also assessed for association with disease activity (DAS28) and plasma inflammatory markers in patients with RA.

RESULTS

Carriage of the IL1RN TTG haplotype was associated with increased odds of more severe rOA compared with age-matched, sex-matched and body mass index-matched individuals. Examination of the osteoarthritis initiative Incidence Subcohort demonstrated that carriage of the TTG haplotype was associated with 4.1-fold (p=0.001) increased odds of incident rOA. Plasma IL-1Ra levels were lower in TTG carriers, while chondrocytes from TTG carriers exhibited decreased secretion of IL-1Ra. In patients with RA, the TTG haplotype was associated with increased DAS28, decreased plasma IL-1Ra and elevations of plasma inflammatory markers (hsCRP, interleukin 6 (IL-6)).

CONCLUSION

Carriage of the IL1RN TTG haplotype is associated with more severe rOA, increased risk for incident OA, and increased evidence of inflammation in RA. These data suggest that the IL1RN TTG risk haplotype, associated with decreased IL-1Ra plasma levels, impairs endogenous 'anti-inflammatory' mechanisms.

Association between polymorphism of interleukin-1 beta and interleukin-1 receptor antagonist gene and asthma risk: a meta-analysis

Background. Asthma is a complex polygenic disease in which gene-environment interactions are important. A number of studies have investigated the polymorphism of IL-1β -511C/T and IL-1RA genes in relation to asthma susceptibility in different populations. However, the results of individual studies have been inconsistent. Accordingly, we conducted a comprehensive meta-analysis to investigate the association between the IL-1β -511C/T and IL-1RA polymorphism and asthma risk. Methods. Data were collected from the following electronic databases: Pub Med, China National Knowledge Infrastructure (CNKI), Chinese Biomedical Literature Database (CBM), ISI Web of Knowledge, and Google Scholar Search databases with the last report up to July 2013. Finally, 15 studies were included in our meta-analysis. We summarized the data on the association between IL-1β -511C/T and IL-1RA polymorphism and risk of asthma in the overall population and performed subgroup analyses by ethnicity, mean of age, and source of controls. Odds ratio (OR) and 95% confidence interval (CI) were used to evaluate the associations between IL-1β -511C/T and IL-1RA polymorphism and asthma risk. Statistical analysis was performed with Review Manager 5.1. Results. A total of 15 case-control studies were included in the meta-analysis of IL-1β -511C/T (1,385 cases and 1,964 controls) and IL-1RA (2,800 cases and 6,359 controls) genotypes. No association was found between IL-1β -511C/T polymorphism and asthma risk (dominant model: OR = 1.11, 95% CI: 0.99–1.25, P = 0.07, P_{Heterogeneity} = 0.06; recessive model: OR = 1.04, 95% CI: 0.91–1.20, P = 0.55, P_{Heterogeneity} = 0.11). Subgroup analysis based on ethnicity (Asian and Caucasian), source of controls (population-based controls and hospital-based controls), and mean of age (adulthood and childhood) did not present any significant association. The overall results showed that the IL-1RA polymorphism was related to an increased risk of asthma (homozygote model: OR = 1.32, 95% CI: 1.12–1.56, P = 0.0009, P_{Heterogeneity} = 0.87; recessive model: OR = 1.39, 95% CI: 1.18–1.63, P = 0.0001, P_{Heterogeneity} = 0.82). Similar results were found in the subgroup analyses by ethnicity, mean of age, and source of controls. Sensitivity analysis did not perturb the results. Conclusions. This meta-analysis provided strong evidence that the IL-1RA polymorphism was a risk factor of asthma, especially in Caucasian populations. However, no association was found for IL-1β -511C/T genotype carriers. Larger scale studies are needed for confirmation.

Interleukin-1 receptor antagonist gene polymorphism and susceptibility to ischemic stroke

Cytokines gene polymorphisms have been implicated in susceptibility to ischemic stroke. This study aims to determine the influence of the polymorphism within the intron 2 of the interleukin- 1 receptor antagonist (IL-1Ra) gene on the susceptibility to stroke. A variable number of tandem repeats (VNTR) in intron 2 of the IL-1Ra gene was analyzed in 148 patients with stroke and 161 healthy volunteers from the same area. The carriage rate of allele 2 of IL-1Ra gene, low producer, was significantly higher in patients with stroke compared to the controls (29% vs 21% p = 0.02). Frequency of IL1RN1/IL1RN1 genotype in the patients was significantly lower than the controls (49% vs 66% p = 0.003). The distribution of homozygous genotypes of IL1RN2 was not different between the controls and stroke patients while the heterozygous genotype was more frequent among the patients. (39% vs 25%, respectively). Multiple logistic regression analysis demonstrated that individuals who carry allele 2 for IL-1Ra gene had a significantly higher risk for ischemic stroke with an odds ratio of 2.48 (95% CI, 1.67, 3.51, p = 0.006). These data suggest that allele 2 of the IL-1Ra intron 2 gene represents a susceptibility factor in the development of ischemic stroke.

IL1RN*2 allele of IL-1receptor antagonist VNTR polymorphism is associated with susceptibility to anklyosing spondylitis in Indian patients

Despite strong linkage of ankylosing spondylitis (AS) with human leukocyte antigen (HLA) B27, its contribution to disease susceptibility is only 15%, and additional genetic factors are likely to be involved in AS. Interleukin (IL)-1 locus has been linked to AS in European population. Thus, we studied IL-1 receptor antagonist polymorphism in Indian patients with AS. One hundred and sixty-two patients with AS and ethnically matched healthy controls were included. IL-1Ra variable number tandem repeat polymorphism was studied by polymerase chain reaction (PCR). HLA B27 was done by amplification refractory mutation system PCR. Clinical details regarding severity of articular disease, presence of peripheral arthritis, and extra-articular manifestations were collected. The mean age of these 162 patients was 35 years, and the mean duration of disease was 10.8 years. Of these 162 patients, 137 were HLA B27 positive. The commoner alleles--IL-1RN*1 and IL-1RN*2--together accounted for 99.5% of the IL-1RN alleles in the control population and 98.5% of the cases. The allele frequency as well as the carriage rate of allele IL-1RN*2 were significantly higher in patients with AS than the control populations (26.3 vs 16.2% and 41.97 vs 22.5%, respectively; p=0.015 and 0.0002). The IL-1RN*2 allele was not associated with any difference in clinical disease expression. The IL-1RN*2 allele is a susceptibility marker for AS in the Indian population but does not influence disease phenotype.

Polymorphism of the interleukin-1 receptor antagonist gene: A factor in susceptibility to rheumatoid arthritis in a Spanish population

OBJECTIVE

To assess whether an interleukin-1 receptor antagonist gene (IL1RN) polymorphism is associated with disease susceptibility and/or severity in a Spanish population of patients with rheumatoid arthritis (RA).

METHODS

An 86-bp variable-number tandem repeat polymorphism within IL1RN intron 2 was analyzed by polymerase chain reaction in genomic DNA obtained from 247 unrelated patients with RA (group A) and 287 healthy control subjects. The polymorphism analysis was repeated in a second group of 194 patients with RA (group B). Clinical information from patients in group A was used to compare activity and severity data in patients stratified according to the different alleles or genotypes. Odds ratios (ORs) with 95% confidence intervals (95% CIs) were used to determine the strength of the association of the different alleles or genotypes with RA activity or severity.

RESULTS

In the control group, the allelic frequencies were 76% for IL1RN*1 (4 repeats), 21% for IL1RN*2 (2 repeats), 3% for IL1RN*3 (5 repeats), and 0.3% for IL1RN*4 (3 repeats). In group A patients with RA, both the frequency (OR 1.47, 95% CI 1.1-1.96, P = 0.007) and carriage rate (OR 1.6, 95% CI 1.1-2.2, P = 0.01) of allele IL1RN*2 were significantly increased. The increased frequency of IL1RN*2 was confirmed in group B patients with RA (OR 1.44, 95% CI 1.1-1.97, P = 0.01). In patients with RA, homozygosity for IL1RN*2 was associated with an increased number of affected articular areas during the first year of followup but not with other parameters of disease activity or severity.

CONCLUSION

Our results suggest that IL1RN has a role in determining susceptibility to RA in the Spanish population.

Analysis of gender-specific atherosclerosis susceptibility in transgenic[hCETP]25DS rat model

Epidemiological and clinical data demonstrate differences in atherosclerotic coronary heart disease prevalence between age-matched men and premenopausal women. Mechanisms underlying relative athero-susceptibility in men and athero-resistance in premenopausal women remain to be elucidated. Lack of informative animal models hinders research. We report here a moderate-expresser line transgenic for human cholesteryl ester transfer protein (CETP) in the Dahl salt-sensitive hypertensive rat strain, Tg25, that recapitulates premenopausal female athero-resistance. Having ascertained identical genetic background, environmental factors, and equivalent CETP hepatic RNA levels, we detect worse hypercholesterolemia, hypertriglyceridemia, coronary plaques and survival outcome in Tg25 male rats compared with Tg25 females. Hepatic transcription profiles of Tg25 males and females normalized to respective gender- and age-matched non-transgenic controls exhibit significant differences. Genes implicated on hierarchical cluster analysis and quantitative real-time RT-PCR pinpoint pathways associated with coronary plaque progression such as inflammation and arachidonic acid epoxygenation, and not just cholesterol metabolism pathways. The data demonstrate gender-specific factors as key modulators of atherosclerosis phenotype and suggest a possible role for the liver in atheroma progression as a large organ source of proatherogenic systemic factors.