Helicobacter pylori virulence genes and host IL-1RN and IL-1beta genes interplay in favouring the development of peptic ulcer and intestinal metaplasia

Helicobacter pylori infection outcome might depend on genotypic polymorphisms of both the bacterium and the host. We ascertained: (1) the functionality of H. pylori oipA gene; (2) the polymorphism of the hostinterleukin (IL-1beta) gene (-31 C/T) and of the IL-1RN gene (intron 2 VNTR); (3) the association between the above genes and the histological and pathological outcome of H. pylori infection. One hundred and sixty-five H. pylori positive and 137 H. pylori negative subjects (23 gastric adenocarcinoma, 58 peptic ulcer, 221 gastritis) were studied. oipA was sequenced, IL-1beta was RFLP analysed. Antral and body mucosal biopsies were histologically evaluated. Functional oipA genes were correlated with cagA gene; both genes were significantly associated with gastritis activity, peptic ulcer and gastric adenocarcinoma. In these patients heterozygousIL-1RN 1/2 and IL-1beta C/T genotypes were more frequent than in gastritis patients. Intestinal metaplasia was associated with cagA, functional oipA and IL-1RN 2 allele. In conclusion, peptic ulcer and the preneoplastic intestinal metaplasia are associated with H. pylori virulence genes and with IL-1RN 2 host allele. An interplay between bacterial virulence factors and cytokines genotypes, is probably the main route causing H. pylori infection to lead to benign mild disease, benign severe disease or preneoplastic lesions.     

Lack of association between pro-inflammatory genotypes of the interleukin-1 (IL-1B -31 C/+ and IL-1RN *2/*2) and gastric cancer/duodenal ulcer in Korean population

IL-1beta is a pro-inflammatory cytokine with multiple biological effects and is a potent inhibitor of gastric acid secretion, and IL-1RN has been shown to be associated with enhanced IL-1beta production in vitro. Recently, it was reported that the pro-inflammatory genotypes, IL-1B -31 C/+ and IL-1RN *2/*2, were associated with an increased risk of gastric cancer in a Caucasian population. We tested the association between the polymorphisms and 190 gastric cancer, 117 duodenal ulcer, and 172 healthy subjects as controls in the Korean population. The allele frequency of IL-1B -31 C was more prevalent in Korean (51%) than in Caucasian (30%), while the frequency of IL-1RN *2 allele was less in Korean (6%) than in Caucasian (27%). Using the IL-1B TT genotype as a reference group, the CC genotype was not associated with an increased risk of gastric cancer or duodenal ulcer in the Korean population (odds ratios (OR)=0.90, 95% confidence interval (CI)=0.50-1.64; OR=0.72, 95% CI=0.36-1.46, respectively). Similarly, IL-1RN*2 was not a risk genotype for either gastric cancer or duodenal ulcer. No association was recognized on the haplotype analysis of the two genes, either. Our results did not support the previous report that IL-1B -31 C/IL-1RN*2 polymorphisms were associated with an increased risk of gastric cancer. The lack of association with duodenal ulcer also suggested that the polymorphisms were not directly related to the acid-secreting capability.     

Imbalance production between interleukin-1beta (IL-1beta) and IL-1 receptor antagonist (IL-1Ra) in bronchial asthma

Genes of the IL-1 family encode three different peptides, IL-1alpha, IL-1beta, and IL-1Ra, respectively. IL-1 operates through IL-1RI, and is involved in airway inflammation in asthmatic subjects, whereas IL-1Ra appears to be a specific competitive inhibitor of IL-1. All genes are on chromosome 2q12-21 where genomewide searches have identified linkage for asthma. To test whether variants of IL-1 relate to asthma, we conducted a genetic association study in a Japanese population. We show that the A2 allele of IL1RN (encoding IL-1Ra) associates with nonatopic asthma [OR = 5.71, 95% CI: 1.63-19. 8, Pc = 0.007]. Both atopic and nonatopic asthmatics with the A2 allele had significantly lower serum IL-1Ra levels in both types of asthmatics. Peripheral blood cells from asthmatics with A2 alleles, however, produced as much IL-1 as did those with A1 homozygotes. Since Th1 and Th2 cytokines differentially regulate the ratio between IL-1beta and IL-1Ra, these findings suggest that dysregulation of IL-1beta/IL-1Ra, probably due to interaction between epithelium and immuno-competent cells in the airway, is important in asthma inflammation.     

IL-1RN VNTR polymorphism and genetic susceptibility to cervical cancer in Portugal

Human Papillomavirus infection is considered as the main etiological factor of cervical cancer (ICC), although, the role of host genetic factors in ICC susceptibility has been increasing. Immunological response is crucial for the prevention of viral associated diseases. Interleukin 1 receptor antagonist (IL-1RN) is considered to be an important regulator of host immunity and several studies have shown a potential role of a 86?bp VNTR polymorphism within intron 2 of the IL-1RN gene in host immune response variability. We investigated the role of this polymorphism in cervical cancer development in Portugal with a case–control study developed with peripheral blood samples from 196 healthy women and 340 women with cervical lesions from the Northern Region of Portugal. We observed that IL-1RN Allele 2 homozygosis was significantly higher in cases than in controls. In fact, IL-1RN A2*A2 homozygous revealed to be associated with an increased risk of HSIL?+?ICC (OR?=?1.90; 95?% IC 1.13–3.21; p?=?0.015). Furthermore, we also observed that median age of onset of HSIL?+?ICC was significantly different (46.0 vs 52.0) in IL-1RN A2*A2 homozygous comparing to non-A2*A2 (p?=?0.028). Our results indicated that IL-1RN A2 allele is associated with an increased susceptibility to cervical cancer development, probably by increasing predisposition to shorter immune responses.     

湖南汉族人群IL-1O启动子和IL-1ra基因多态性与SLE相关性研究

目的:研究湖南汉族人群IL-10启动子和IL-1受体拮抗剂(IL-1ra)的基因多态性,探讨IL-10启动子和IL-1ra基因多态性与SLE疾病的关系。方法:PCR和限制性内切酶酶切分析SLE患者(n=83)和正常对照人群(n=125)IL-10启动子和IL-1ra基因多态性,对基因频率进行分析。结果:湖南汉族人群IL-1ra及IL-10启动子基因具有多态性;SLE患者IL-1RN*1等位基因的频率显著高于正常对照组(P<0.05,RR=5);SLE患者IL-10启动子区-597位*A、-824位*T和ACC亚型的基因频率高于正常对照组(P<0.001)。结论:SLE患者IL-1RN*1的基因频率、IL-10启动子区-597位和-824位的基因多态性与正常人比较有显著差异,提示以上基因可能与SLE的发病有一定相关性。     

Production of interleukin (IL)-1beta, IL-1 receptor antagonist and IL-10 by blood mononuclear cells in chronic arthritis

Joint erosion is a prevalent feature of rheumatoid arthritis (RA) but not of many other chronic inflammatory arthritides (non-RA). Joint destruction is mediated by cytokines, primarily interleukin (IL)-1 and tumour necrosis factor. Less erosive activity in patients with non-RA compared to RA might be related to factors that inhibit production and/or function of IL-1. Release of IL-1beta, and the two antagonists, IL-1 receptor antagonist (IL-1ra) and IL-10 from blood mononuclear cells were therefore quantitated by ELISA in 22 patients with RA, 11 with non-RA and 15 healthy age-matched controls. Release of IL-1beta was comparable between the three groups but only detectable in cultures stimulated with lipopolysaccharide; it decreased in patients treated with prednisolone: 3.8 ng/10(6)monocytes (median) vs 11.7 (P=0.045). Release of IL-1ra was in all but IgG-stimulated cultures comparable between groups. The ratio of IL-1ra/IL-1beta was elevated in LPS-stimulated cells from RA patients only: 2.0 versus 1.3 (P=0.02). In contrast, IgG-induced IL-1ra release was significantly elevated only in non-RA patients: 95 ng/10(6)monocytes vs 40 (P=0.014), and the levels correlated positively to those of blood CRP (P=0.02). Though stimulated release of IL-10 was similar between the three groups, the levels were lower in non-erosive than erosive arthritis patients, and controls (P=0. 05). In conclusion, increased IgG-stimulated IL-1ra release and elevated IL-1ra/IL-1beta ratio may protect against actions of IL-1 in vivo, and decreased release of IL-10 might be related to features of non-erosive arthritis.     

Interleukin 1 receptor antagonist gene polymorphism association with lichen sclerosus

Cytokines play key roles in immune responses, inflammation and fibrosis. The balance between levels of cytokines, their receptors and specific inhibitors controls inflammatory reactions in tissues. The pathogenesis of lichen sclerosus is unknown but probably involves cytokine mediators such as interleukin 1 (IL-1) and interleukin 1 receptor antagonist (IL-1ra). The IL-1ra is a competitive inhibitor of IL-1 and IL-1, and therefore is a powerful endogenous anti-inflammatory molecule. The gene encoding IL-1ra (designated IL-1RN) has a variable number tandem repeat polymorphism in intron 2. There are five alleles of the gene corresponding to 2, 3, 4, 5 and 6 repeats of an 86-bp sequence. We have determined allele frequencies in a control population and a group of 78 patients with lichen sclerosus. The frequency of one of the alleles is related to increasing disease severity. Thus, IL-1RN may be a candidate gene or severity factor for lichen sclerosus or may possibly be a linked marker to another, as yet undefined, gene.     

Interleukin-1 receptor antagonist gene polymorphism and circulating levels of human immunodeficiency virus type 1 RNA in Brazilian women

Interleukin-1 receptor antagonist (IL-1ra) gene polymorphisms in 83 human immunodeficiency virus (HIV)-seropositive women were evaluated. Fourteen of the subjects (16.9%) were homozygous for IL-1ra allele 2 (IL-1RN*2). These women had a lower median level of HIV RNA than did women homozygous for allele 1 (IL-1RN*1) (P = 0.01) or heterozygous for both alleles (P = 0.04). Among 46 subjects not receiving antiretroviral treatment, HIV levels were also reduced in IL-1RN*2 homozygous individuals (P < 0.05). There was no relation between IL-1ra alleles and CD4 levels.     

Interleukin-1B (-511) gene polymorphism is associated with acute coronary syndrome in the Turkish population

Objectives: acute coronary syndrome (ACS) is defined as an inflammatory disease associated with development of atherosclerosis and instability. IL-1 is a candidate inflammatory cytokine that is thought to trigger ACS. The purpose of this study was to determine the relationship between IL-1 gene family polymorphisms (IL-1RN, IL-1B in positions -511 and +3953) and ACS in the Turkish population. Methods: a total of 381 people participated in the study, with 117 control subjects and 264 ACS patients. Of the 264 ACS patients, 112 were diagnosed with stable angina pectoris (SAP) and 152 were diagnosed with unstable angina pectoris (USAP). The polymerase chain reaction (PCR) was used to determine the genotype of IL-1RN. The genotypes of IL-1B (-511 and +3953) were determined by PCR, followed by restriction enzyme digestion of the PCR products. Results: there were no significant differences in both IL-1RN, IL-1B (-511 and +3953) genotype distributions and IL-1RN allele frequencies between ACS patients and the control subjects. In addition, no association was observed in the allele frequency of IL-1B (-511 and +3953) between ACS patients and controls (p = 0.113 and p = 0.859, respectively), or between SAP patients and controls (p = 0.575 and p = 0.359, respectively). However, IL-1B allele 1 (C) (-511) polymorphism in USAP patients was found to be significantly different from that of control subjects (p = 0.041, OR: 2.01; 95% CI: 1.985-3.933). A significant difference was also observed between USAP and SAP patients for IL-1B (+3953) allele 1 (C) polymorphism; (p = 0.043, OR: 1.522; 95% CI: 1.012-2.88). Conclusion: these results show that IL-1RN gene polymorphism has no association with ACS. However, the allele 1 (C) of IL-1B (-511) may be a risk factor for susceptibility to USAP in the Turkish population.     

Genomic dissection and prioritizing of candidate genes of QTL for regulating spontaneous arthritis on chromosome 1 in mice deficient for interleukin-1 receptor antagonist

Rheumatoid arthritis is a heterogeneous disease with clinical and biological polymorphisms. IL-1RN is a protein that binds to interleukin-1 (IL-1) receptors and inhibits the binding of IL-1-alpha and IL-1-beta. IL-1RN levels are elevated in the blood of patients with a variety of infectious, immune, and traumatic conditions. Balb/c mice deficient in IL-1ra (mouse gene of IL-1RN) develop spontaneous autoimmune arthritis while DBA/1 mice deficient in IL-1ra do not. Previously, we identified a major QTL that regulates the susceptibility to arthritis in Balb/c mice with IL-1ra deficiency. In this study, we found that the QTL may contain two peaks that are regulated by two sets of candidate genes. By haplotype analysis, the total genomic regions of candidate genes were reduced from about 19 Mbp to approximately 9 Mbp. The total number of candidate genes was reduced from 208 to 21.     

Serum IL-1beta, IL-2, and IL-6 in insulin-dependent diabetic children

Insulin-dependent diabetes mellitus (IDDM) is a chronic disease characterized by T-cell-dependent autoimmune destruction of the insulin-producing beta cells in the pancreatic islets of Langerhans, resulting in an absolute lack of insulin. T cells are activated in response to islet-dominant autoantigens, the result being the development of IDDM. Insulin is one of the islet autoantigens responsible for the activation of T-lymphocyte functions, inflammatory cytokine production, and development of IDDM. The aim of this study was to investigate serum concentrations of interleukin (IL)-1beta, IL-2, IL-6, and tumor necrosis factor (TNF)-alpha in children IDDM. The study population consisted of 27 children with IDDM and 25 healthy controls. Children with IDDM were divided into three subgroups: (1) previously diagnosed patients (long standing IDDM) (n : 15), (2) newly diagnosed patients with diabetic ketoacidosis (before treatment) (n : 12), and (3) newly diagnosed patients with diabetic ketoacidosis (after treatment for two weeks) (n : 12). In all stages of diabetes higher levels of IL-1beta and TNF-alpha and lower levels of IL-2 and IL-6 were detected. Our data about elevated serum IL-1beta, TNF-alpha and decreased IL-2, IL-6 levels in newly diagnosed IDDM patients in comparison with longer standing cases supports an activation of systemic inflammatory process during early phases of IDDM which may be indicative of an ongoing beta-cell destruction. Persistence of significant difference between the cases with IDDM monitored for a long time and controls in terms of IL-1beta, IL-2, IL-6, and TNF-alpha supports continuous activation during the late stages of diabetes.     

Cutting edge: IL-1 controls the IL-23 response induced by gliadin, the etiologic agent in celiac disease

IL-23 has been implicated in the pathogenesis of several tissue-specific autoimmune diseases. Currently, celiac disease (CD) is the only autoimmune disease in which both the major genetic (95% HLA-DQ2(+)) and etiologic factors (dietary glutens) for susceptibility are known. We demonstrate that wheat gliadin induces significantly greater production of IL-23, IL-1beta, and TNF-alpha in PBMC from CD patients compared with HLA-DQ2(+) healthy controls, strongly advocating a role for IL-23 in the pathogenesis of CD. Moreover, IL-1beta alone triggered IL-23 secretion and the IL-1R antagonist inhibited this response in PBMC and purified monocytes. This sequence of events was replicated by beta-glucan, another substance known to induce IL-23 production. Our results suggest that gliadin and beta-glucan stimulate IL-23 secretion through induction of the IL-1 signaling pathway and reveal for the first time that the IL-1 system regulates IL-23 production. These findings may provide therapeutic targets for this disease and other inflammatory conditions mediated by IL-23.     

The human IL-1 receptor antagonist gene (IL1RN) maps to chromosome 2q14-q21, in the region of the IL-1 alpha and IL-1 beta loci.

The IL-1 receptor antagonist (IL-1RN) is a protein that binds to IL-1 receptors and inhibits the binding of IL-1 alpha and IL-1 beta. As a consequence, the biological activity of these two cytokines is neutralized in physiological and pathophysiological immune and inflammatory responses. In this study, using a panel of somatic rodent-human cell hybrids, we show that the gene for the human interleukin-1 receptor antagonist (IL1RN) maps to the long arm of chromosome 2. Previously, we described a length variation polymorphism within the second intron of the IL-1RN gene (Steinkasserer et al., 1991, Nucleic Acids Res. 19: 5095). Segregation of this, together with an IL-1 alpha polymorphism, was followed in a panel of five CEPH families. Linkage analysis permitted the mapping of the IL-1RN gene to band q14-q21 in the region for the IL-1 alpha and IL-1 beta loci. This study supports the view that an early gene duplication event resulted in the creation of an interleukin-1 gene family.     

The effect of an interleukin receptor antagonist (IL-1ra) on colonocyte eicosanoid release

We investigated whether an interleukin 1 receptor antagonist (IL-1ra) altered cellular release of prostanoids and leukotrienes in a transformed colonic cell line (CACO-2) in the presence of proinflammatory stimuli. Cellular inflammation was induced by treatment with lipopolysaccharide (LPS) or the cytokine, interleukin 1 beta (IL-1(beta)). In a separate set of experiments, cells were pretreated with IL-1ra prior to exposure to LPS or IL-1(beta). Prostaglandin E(2) and leukotriene B(4) (LTB(4)) levels were quantified by ELISA assays. Both LPS and IL-1(beta) exposure were noted to stimulate cellular PGE(2) release, a response which was significantly inhibited by IL-1ra treatment. Either stimulant when administered alone failed to stimulate release of LTB(4). When administered after IL-1ra pretreatment however, both stimuli caused a significant increase in LTB(4) release. These results suggest that a cytokine receptor antagonist can selectively influence eicosanoid production in this cell line. Furthermore, this study suggests that a IL-1ra may have a future clinical role in the treatment of inflammatory disorders of the colon which are intimately linked to enhanced eicosanoid synthesis.     

Prognostic value of interleukin-1 receptor antagonist gene polymorphism and cytomegalovirus seroprevalence in patients with coronary artery disease

Background

Chronic inflammatory stimuli such as cytomegalovirus (CMV) infection and various genetic polymorphisms determining the inflammatory response are assumed to be important risk factors in atherosclerosis. We investigated whether patients with stable coronary artery disease (CAD) and homozygous for allele 2 of the interleukin 1 receptor antagonist (IL-1RA) gene and seropositive for CMV represent a group particular susceptible for recurrent cardiovascular events.

Methods

In a series of 300 consecutive patients with angiographically defined CAD a prospective follow-up was conducted (mean age 57.9 years, median follow-up time 38.2 months).

Results

No statistically significant relationship was found between CMV serostatus and IL-1RN*2 (alone or in combination) and risk for future cardiovascular events (CVE). The hazard ratio (HR) for a CVE given positive CMV-serology and IL-1RN*2 was 1.07 (95% confidence interval (CI) 0.32–3.72) in the fully adjusted model compared to seronegative CMV patients not carrying the IL-1RN*2 allele. In this prospective cohort study involving 300 patients with angiographically defined CAD at baseline, homozygousity for allele 2 of the IL-1 RA and seropositivity to CMV alone and in combination were not associated with an increased risk for cardiovascular events during follow-up; in addition, combination of the CMV-seropositivity and IL-1RN*2 allele were not associated with a proinflammatory response

Conclusion

Our study suggests that seropositivity to CMV and IL-1RA*2 genotype alone or in combination might not be a strong risk factor for recurrent cardiovascular events in patients with manifest CAD, and is not associated with levels of established inflammatory markers.     

Action of intracellular IL-1Ra (Type 1) is independent of the IL-1 intracellular signalling pathway

The balance between IL-1 and its naturally occurring inhibitor IL-1 receptor antagonist (IL-1ra) is critical in determining the inflammatory response. Four splice variants of the IL-1ra gene have been identified; one secreted (sIL-1ra) and three intracellular (icIL-1ra1-3). The biological roles of the intracellular isoforms remain largely unclear. We wished to determine whether icIL-1ra1 had intracellular functions regulating IL-1 signalling. Signalling was determined using an NF-kappaB reporter assay measuring induction of the IL-8 promoter in transfected cells. Over-expression of icIL-1ra1 in HeLa cells had no effect on IL-1 stimulated IL-8 activity. In contrast over-expression of sIL-ra significantly attenuated IL-1 activity. In addition, transfection of icIL-1ra1 in HeLa cells did not cause inhibition of IL-8 promoter activity following over-expression of the IL-1 signalling components MyD88, IRAK-1, TRAF-6, Ikappakappabeta or RelA. This implies that icIL-1ra1 does not act to alter IL-1 mediated intracellular signalling in this system. We investigated whether ATP and/or over-expression of the P2X7 receptor caused icIL-1ra1 inhibition of IL-1beta mediated IL-8 reporter activation, by permitting its release. In HeLa cells, no effect of icIL-1ra1 was observed in ATP stimulated and/or P2X7 transfected cells, compared to a significant inhibition in sIL-1ra transfected cells. However, in endothelial cells stimulated with ATP, the released fraction was effective in attenuating IL-1beta activation of the IL-8 reporter. These results suggest that icIL-1ra1 does not act at an intracellular level to alter IL-1 mediated signalling, and is effective in inhibiting IL-1 responses only when released in an ATP-dependent and cell type specific manner.