The rs7044343 Polymorphism of the Interleukin 33 Gene Is Associated with Decreased Risk of Developing Premature Coronary Artery Disease and Central Obesity, and Could Be Involved in Regulating the Production of IL-33

IL-33 controls IL-22-dependent antibacterial defense by modulating the microbiota

IL-22 plays a critical role in defending against mucosal infections, but how IL-22 production is regulated is incompletely understood. Here, we show that mice lacking IL-33 or its receptor ST2 (IL-1RL1) were more resistant to Streptococcus pneumoniae lung infection than wild-type animals and that single-nucleotide polymorphisms in IL33 and IL1RL1 were associated with pneumococcal pneumonia in humans. The effect of IL-33 on S. pneumoniae infection was mediated by negative regulation of IL-22 production in innate lymphoid cells (ILCs) but independent of ILC2s as well as IL-4 and IL-13 signaling. Moreover, IL-33's influence on IL-22-dependent antibacterial defense was dependent on housing conditions of the mice and mediated by IL-33's modulatory effect on the gut microbiota. Collectively, we provide insight into the bidirectional crosstalk between the innate immune system and the microbiota. We conclude that both genetic and environmental factors influence the gut microbiota, thereby impacting the efficacy of antibacterial immune defense and susceptibility to pneumonia.

Interleukin (IL)-33 immunobiology in asthma and airway inflammatory diseases

OBJECTIVE

Identify key features of IL-33 immunobiology important in allergic and nonallergic airway inflammatory diseases and potential therapeutic strategies to reduce disease burden.

DATA SOURCES

PubMed, clinicaltrials.gov.

STUDY SELECTIONS

A systematic and focused literature search was conducted of PubMed from March 2021 to December 2021 using keywords to either PubMed or BioMed Explorer including IL-33/ST2, genetic polymorphisms, transcription, translation, post-translation modification, nuclear protein, allergy, asthma, and lung disease. Clinical trial information on IL-33 was extracted from clinicaltrials.gov in August 2021.

RESULTS

In total, 72 publications with relevance to IL-33 immunobiology and/or clinical lung disease were identified (allergic airway inflammation/allergic asthma n = 26, non-allergic airway inflammation n = 9, COPD n = 8, lung fibrosis n = 10). IL-33 levels were higher in serum, BALF and/or lungs across inflammatory lung diseases. Eight studies described viral infections and IL-33 and 4 studies related to COVID-19. Mechanistic studies (n = 39) including transcript variants and post-translational modifications related to the immunobiology of IL-33. Single nucleotide polymorphism in IL-33 or ST2 were described in 9 studies (asthma n = 5, inflammatory bowel disease n = 1, mycosis fungoides n = 1, ankylosing spondylitis n = 1, coronary artery disease n = 1). Clinicaltrials.gov search yielded 84 studies of which 17 were related to therapeutic or biomarker relevance in lung disease.

CONCLUSION

An integral role of IL-33 in the pathogenesis of allergic and nonallergic airway inflammatory disease is evident with several emerging clinical trials investigating therapeutic approaches. Current data support a critical role of IL-33 in damage signaling, repair and regeneration of lungs.

IL-33/ST2 immunobiology in coronary artery disease: A systematic review and meta-analysis

The IL-33/ST2 axis is reported to be controversially associated with coronary artery disease (CAD). A systematic review of the association between the IL-33/ST2 axis and CAD revealed that IL-33/ST2 plays a protective role in CAD and serum sST2 and IL-33 levels are increased in patients with cardiovascular disease. Therefore, the association of IL-33/ST2 single nucleotide polymorphisms (SNPs) with CAD prevalence, prognosis, and risk factors was assessed by performing a meta-analysis. Through a literature search of relevant articles in various databases using the relevant keywords, seven studies were included in the analysis. The meta-analysis showed that the IL-33/ST2 axis was associated with increased CAD risk [pooled odds ratio (OR) = 1.17, 95% confidence interval (CI): 1.13–1.20]. Gene subgroup analysis showed a close association of IL1RL1 (OR = 1.25, 95% CI: 1.20–1.30; I² = 85.9%; p = 0.000) and IL1RAcP (OR = 1.42, 95% CI: 1.26–1.60; I² = 27.1%; p = 0.203) with increased CAD risk. However, the association for the IL-33 gene was not statistically significant. SNPs rs7044343 (T), rs10435816 (G), rs11792633 (C) in IL-33 gene were associated with a protective effect in CAD. However, rs7025417 (T) in IL-33, rs11685424 (G) in IL1RL1, rs950880 (A) in sST2, and rs4624606 (A) in IL1RAcP were related to increased CAD risk. Overall, polymorphisms in IL-33/ST2 axis components were associated with increased CAD risk. These results may help identify key features of IL-33/ST2 immunobiology in CAD along with potential treatment strategies to lower disease burden.

Role of altered IL-33/ST2 immune axis in the immunobiology of Guillain-Barré syndrome

BACKGROUND

IL-33/ST2 immune axis plays crucial roles in infection and immunity. A dysregulated IL-33/ST2 axis can induce autoimmune reaction and inflammatory responses. Guillain-Barré Syndrome (GBS) is an acute peripheral neuropathy, mostly caused by post-infection autoimmunity. The role of IL-33/ST2 axis is not known in GBS. This study aimed to explore the role of IL-33/ST2 axis in GBS.

METHODS

Three single nucleotide polymorphisms (SNPs) of Il33 gene (rs16924159; rs7044343; rs1342336) and three SNPs of Il1rl1 gene (rs10192157, rs1041973, rs10206753), coding for ST2 were genotyped in 179 GBS patients and 186 healthy controls by TaqMan Allelic Discrimination Assay. Plasma levels of IL-33 and sST2 were measured in a subset of GBS (n=80) and healthy controls (n=80) by ELISA.

RESULTS

The frequencies of CC genotype of rs10192157 (p=0.043) and TT genotype of rs10206753 (p=0.036) SNPs of Il1rl1 gene differed significantly between GBS patients and healthy subjects. Gene-gene interaction between Il33 and Il1rl1 genes also conferred significant risk to GBS. In addition, the plasma sST2 levels were significantly elevated in GBS patients compared to healthy subjects (24,934.31 ± 1.81 pg/ml vs. 12,518.97 ± 1.51 pg/ml, p<0.001). Plasma sST2 levels showed a significant correlation with the disability scores at the peak of neurological deficit in GBS patients.

CONCLUSIONS

IL-33/ST2 axis is suggested to influence the immunopathogenesis of GBS. Genetic variants of Il1rl1 gene might serve as a risk determinant of GBS and plasma sST2 levels might emerge as a biomarker of severity of GBS, if replicated further by other studies.

Innate-Immunity Genes in Obesity

The main functions of adipose tissue are thought to be storage and mobilization of the body’s energy reserves, active and passive thermoregulation, participation in the spatial organization of internal organs, protection of the body from lipotoxicity, and ectopic lipid deposition. After the discovery of adipokines, the endocrine function was added to the above list, and after the identification of crosstalk between adipocytes and immune cells, an immune function was suggested. Nonetheless, it turned out that the mechanisms underlying mutual regulatory relations of adipocytes, preadipocytes, immune cells, and their microenvironment are complex and redundant at many levels. One possible way to elucidate the picture of adipose-tissue regulation is to determine genetic variants correlating with obesity. In this review, we examine various aspects of adipose-tissue involvement in innate immune responses as well as variants of immune-response genes associated with obesity.

Efficacy and safety of coronary stent intervention for coronary heart disease and its impact on short-term and long-term prognosis

OBJECTIVE

To investigate the effect of coronary stent intervention on the efficacy, safety, and short-term and long-term prognosis of patients with coronary heart disease (CHD).

METHODS

From March 2016 to November 2017, 60 cases of CHD patients receiving coronary stent interventiontherapy (research group) and 42 cases of patients receiving conventional drug therapy (control group) in our hospital were recruited as research objects. The clinical efficacy, safety and prognosis in the two groups were compared, and the levels of matrix metalloproteinase-9 (MMP-9) and interleukin-33 (IL-33) in the two groups were measured before and after treatment.

RESULTS

The clinical efficacy and prognostic quality of life of patients in the research group were higher than those in the control group (P<0.050), and the serum levels of MMP-9 and IL-33 in the research group were higher than those in the control group after treatment (P<0.050).

CONCLUSION

Compared with drug therapy alone, coronary stent intervention therapy has better clinical efficacy and short-term and long-term prognosis in treating CHD, but it is easy to promote inflammatory reaction after surgery. Therefore, attention should be paid to the control of inflammation before and after treatment.

IL-33 Gene Polymorphisms as Potential Biomarkers of Disease Susceptibility and Response to TNF Inhibitors in Rheumatoid Arthritis, Ankylosing Spondylitis, and Psoriatic Arthritis Patients

Objective

Rheumatoid arthritis (RA), ankylosing spondylitis (AS), and psoriatic arthritis (PsA) belong to inflammatory rheumatic diseases, the group of conditions of unknown etiology. However, a strong genetic component in their pathogenesis has been well established. A dysregulation of cytokine networks plays an important role in the development of inflammatory arthritis. Interleukin 33 (IL-33) is a recently identified member of the IL-1 family. To date, the significance of IL-33 in inflammatory arthritis has been poorly studied. This research aimed to investigate the potential of IL-33 gene polymorphisms to serve as biomarkers for disease susceptibility and TNF inhibitor response in RA, AS, and PsA patients.

Materials and Methods

In total, 735 patients diagnosed with RA, AS, and PsA and 229 healthy individuals were enrolled in the study. Genotyping for three single nucleotide polymorphisms (SNPs) within the IL-33 gene, namely, rs16924159 (A/G), rs10975519 (T/C), and rs7044343 (C/T), was performed using polymerase chain reaction amplification employing LightSNiP assays.

Results

In the present study, the IL-33 rs10975519 CC genotype was associated with a decreased risk of developing RA in females, while the IL-33 rs16924159 polymorphism was associated with the efficacy of anti-TNF therapy and clinical parameters for RA and AS patients. The IL-33 rs16924159 AA genotype correlated with higher disease activity and worse clinical outcomes in RA patients treated with TNF inhibitors, and AS patients carrying the IL-33 rs16924159 AA genotype had higher disease activity and a worse response to anti-TNF therapy. That indicates a deleterious role of the IL-33 rs16924159 AA genotype in the context of RA, as well as AS.

Conclusions

The obtained results suggest that IL-33 gene polymorphisms might be potential candidate biomarkers of disease susceptibility and anti-TNF treatment response in patients with inflammatory rheumatic diseases.

Interleukin-33 gene polymorphisms and chronic obstructive pulmonary disease in the Chinese Han population

Objective

To investigate the relationship between interleukin (IL)-33 gene polymorphisms rs928413 and rs7044343 with chronic obstructive pulmonary disease (COPD) in the Chinese Han population.

Method

We assessed IL-33 rs928413 and rs7044343 polymorphisms by Sanger sequencing of PCR products amplified from the genomic DNA of 160 COPD patients and 123 healthy controls.

Results

There was no significant difference in the distribution of rs928413 AA, AG, or AA genotypes or rs7044343 CC, CT, or TT genotypes between the two groups. However, COPD patients had a significantly higher frequency of the rs928413 G allele G (14.1% vs 7.3%, respectively). This allele was significantly associated with susceptibility to COPD (odds ratio [OR]: 2.04, 95% confidence interval [CI]: 1.12–3.57). The rs928413 dominant inheritance model was associated with COPD susceptibility (OR: 2.08, 95%CI: 1.09–4.04).

Conclusion

The G allele of rs928413 and the rs928413 dominant inheritance model were associated with susceptibility to COPD in the Chinese Han population.

Association of Common Variants in the IL-33/ST2 Axis with Ischemic Stroke

BACKGROUND

Recent studies have reported that the levels of serum interleukin-33 (IL- 33) and its receptor, suppression of tumorigenicity 2 (ST2), are potential biomarkers for susceptibility of cardiovascular diseases. However, the genetic association of the IL-33/ST2 axis with cardiovascular diseases remains controversial.

OBJECTIVE

We aimed to investigate the association between common variants in the IL-33/ST2 axis and ischemic stroke in the Han Chinese population.

METHODS

We consecutively enrolled 1166 patients with ischemic stroke and 1079 age- and gender- matched controls. Eight single nucleotide polymorphisms (SNPs) within IL-33/ST2 axis were genotyped using the improved Multiple Ligase Detection Reaction platform. We analyzed the association between the tested SNPs and ischemic stroke at both the genotype and haplotype levels.

RESULTS

Binary logistic regression analysis indicated that rs10435816 (additive model: odds ratio [OR]=0.72, 95% confidence interval [CI], 0.54-0.95; recessive model: OR=0.72, 95%CI, 0.56- 0.94) was associated with a decreased risk of ischemic stroke after adjustment of confounding factors. Subgroup analysis indicated that rs10435816 (additive model: OR=0.61, 95%CI, 0.41-0.89; recessive model: OR=0.56, 95%CI, 0.40-0.80), rs7025417 (additive model: OR=0.57, 95%CI, 0.39-0.83), rs11792633 (additive model: OR=0.66, 95%CI, 0.46-0.95; recessive model: OR=0.67, 95%CI, 0.49-0.93), and rs7044343 (additive model: OR=0.69, 95%CI, 0.48-0.97; recessive model: OR=0.67, 95%CI, 0.49-0.91) were associated with a decreased risk of large-artery atherosclerosis stroke after adjustment of confounding factors.

CONCLUSION

Our findings suggested an association between common variants in the IL-33/ST2 axis and a decreased risk of ischemic stroke in the Han Chinese population.

Association between IL-33 Gene Polymorphism (Rs7044343) and Risk of Allergic Rhinitis

BACKGROUND

Allergic rhinitis (AR) is a T helper type 2 (Th2)-mediated upper airways disease in which genetics factors including cytokine genes play a prominent role. Interleukin-33 (IL-33) is a major cytokine for naive T cells polarization into Th2 phenotype as well as enhances the secretion of Th2 cytokines. The aim of the present study was to investigate the relationship between IL-33 single nucleotide polymorphisms (SNPs) and IL-33 serum level with Allergic rhinitis.

METHODS

Blood samples were collected from 130 AR patients and 130 healthy individuals. SNPs (rs7044343 C > T, rs1929992 A > G, rs12551256 A > G) of IL-33 gene were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Serum level of IL-33 was measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Statistical analysis showed that the TT genotype (OR = 1.996, CI: 1.168-3.412, P = .01), as well as the T allele (OR = 0.675, CI: 0.476-0.957, P = .02) of rs7044343 C > T were significantly associated with reduced risk of AR. In addition, individuals carrying the TT genotype were associated with lower levels of IL-33 compared to subjects with CC and CT genotypes; however, these differences were not statistically significant. No association was found between rs1929992 and rs12551256 variants and risk of AR, but the GG genotype from rs1929992 A > G was associated with increased serum levels of IL-33 in control group (p = .01). Furthermore, serum IL-33 levels were not significantly different between AR patients and healthy controls (p > .05).

CONCLUSION

Our results suggest that the TT genotype of rs7044343 C > T may act as a protective agent against allergic rhinitis.

Application of Genome-Wide Association Studies in Coronary Artery Disease

Coronary artery disease (CAD) is a complex disease caused by the combination of environmental and genetic factors. It is one of the leading causes of death and disability in the world. Much research has been focussed on CAD genetic mechanism. In recent years, genome-wide association study (GWAS) has developed rapidly around the world. Medical researchers around the world have successfully discovered a series of CAD genetic susceptibility genes or susceptible loci using medical research strategies, leading CAD research toward a new stage. This paper briefly summarizes the important progress made by GWAS for CAD in the world in recent years, and then analyzes the challenges faced by GWAS at this stage and the development trend of future research, to promote the transformation of genetic research results into clinical practice and provide guidance for further exploration of the genetic mechanism of CAD.

Stromal cells maintain immune cell homeostasis in adipose tissue via production of interleukin-33

Obesity is driven by chronic low-grade inflammation resulting from dysregulated immune cell accumulation and function in white adipose tissue (WAT). Interleukin-33 (IL-33) is a key cytokine that controls innate and adaptive immune cell activity and immune homeostasis in WAT, although the sources of IL-33 have remained controversial. Here, we show that WAT-resident mesenchyme-derived stromal cells are the dominant producers of IL-33. Adipose stem and progenitor cells (ASPCs) produced IL-33 in all WAT depots, whereas mesothelial cells served as an additional source of IL-33 in visceral WAT. ASPC-derived IL-33 promoted a regulatory circuit that maintained an immune tone in WAT via the induction of group 2 innate lymphoid cell-derived type 2 cytokines and maintenance of eosinophils, whereas mesothelial IL-33 also acted as an alarmin by inducing peritoneal immune response upon infection. Together, these data reveal a previously unrecognized regulatory network between tissue-resident progenitor cells and innate lymphoid cells that maintains immune homeostasis in adipose tissue.

The interplay of type 2 immunity, helminth infection and the microbiota in regulating metabolism

Type 2 immunity has recently emerged as a critical player in metabolic status, with numerous studies investigating the role of type 2 immune cells within adipose tissue. Metabolic dysfunction is often characterised as a low-grade or chronic inflammatory state within tissues, and type 2 immunity may facilitate a return to metabolic homeostasis. A complex network of type 2 resident cells including M2 macrophages, eosinophils and ILC2s has been identified within adipose tissue. Although the effector cells in this equilibrium have not been clearly identified, any alteration of the type 2 microenvironment resulted in an altered metabolic state. Historically, the type 2 immune response has been associated with helminth infection. The type 2 immune response drives host resistance and plays an important role in promoting tissue repair following the migration of helminth larvae through tissues. Although helminths are largely eradicated in developed countries, infection rates remain high in poor communities within the developing world. Interestingly, there is strong evidence that helminth infection is inversely correlated with autoimmune or inflammatory disorders. Recently, an increasing amount of epidemiological and field studies suggest that it could be the same for obesity and metabolic syndrome. In the current review, we summarise the literature linking type 2 immunity to improved adipose tissue function. We then discuss more recent evidence indicating that helminth infection can provide protection against metabolic syndrome. Lastly, we explore the possible contributions of altered nutrient uptake, adipose tissue function and/or the intestinal microbiota with the ability of helminths to alter metabolic status.

Interleukin-33 in Systemic Sclerosis: Expression and Pathogenesis

Interleukin-33 (IL-33), a member of the IL-1 superfamily, functions as a traditional cytokine and nuclear factor. It is proposed to have an “alarmin” role. IL-33 mediates biological effects by interacting with the ST2 receptor and IL-1 receptor accessory protein, particularly in innate immune cells and T helper 2 cells. Recent articles have described IL-33 as an emerging pro-fibrotic cytokine in the immune system as well as a novel potential target for systemic sclerosis. Here, we review the available information and focus on the pleiotropic expression and pathogenesis of IL-33 in systemic sclerosis, as well as the feasibility of using IL-33 in clinical applications.

Conflicting vascular and metabolic impact of the IL-33/sST2 axis

Interleukin 33 (IL-33), which is expressed by several immune cell types, endothelial and epithelial cells, and fibroblasts, is a cytokine of the IL-1 family that acts both intra- and extracellularly to either enhance or resolve the inflammatory response. Intracellular IL-33 acts in the nucleus as a regulator of transcription. Once released from cells by mechanical stress, inflammatory cytokines, or necrosis, extracellular IL-33 is proteolytically processed to act in an autocrine/paracrine manner as an 'alarmin' on neighbouring or various immune cells expressing the ST2 receptor. Thus, IL-33 may serve an important role in tissue preservation and repair in response to injury; however, the actions of IL-33 are dampened by a soluble form of ST2 (sST2) that acts as a decoy receptor and is produced by endothelial and certain immune cells. Accumulating evidence supports the conclusion that sST2 is a biomarker of vascular health with diagnostic and/or prognostic value in various cardiovascular diseases, including coronary artery disease, myocardial infarction, atherosclerosis, giant-cell arteritis, acute aortic dissection, and ischaemic stroke, as well as obesity and diabetes. Although sST2 levels are positively associated with cardiovascular disease severity, the assumption that IL-33 is always beneficial is naïve. It is increasingly appreciated that the pathophysiological importance of IL-33 is highly dependent on cellular and temporal expression. Although IL-33 is atheroprotective and may prevent obesity and type 2 diabetes by regulating lipid metabolism, IL-33 appears to drive endothelial inflammation. Here, we review the current knowledge of the IL-33/ST2/sST2 signalling network and discuss its pathophysiological and translational implications in cardiovascular diseases.

The IL-10-1082 (rs1800896) G allele is associated with a decreased risk of developing premature coronary artery disease and some IL-10 polymorphisms were associated with clinical and metabolic parameters. The GEA study

Interleukin 10 (IL-10) is an anti-inflammatory cytokine with a protective role in the formation and the development of the atherosclerotic plaque. The aim of the present study was to establish if IL-10 gene polymorphisms are associated with the development of premature coronary artery disease (pCAD) and cardiovascular risk factors in Mexican individuals. Three IL-10 gene polymorphisms [-592C/A (rs1800872), -819C/T (rs1800871), and -1082 A/G (rs1800896)] and IL-10 plasma levels were analyzed in 2266 individuals (1160 pCAD patients and 1106 healthy controls). Under recessive and co-dominant2 models, the -1082 A/G (rs1800896) G allele was associated with decreased risk of developing pCAD (OR = 0.572, P_rec = 0.022 and OR = 0.567, P_cod2 = 0.023). In pCAD patients, the polymorphisms were associated with hyperinsulinemia, small and dense LDLs, hypertension, and diabetes mellitus. In the control group, the polymorphisms were associated with hypertension, hyperuricemia, and small and dense LDLs. pCAD patients have significantly higher IL-10 plasma levels than healthy controls [0.91 (0.55-1.67) pg/mL vs 0.45 (0.24-0.98) pg/mL, respectively, P < 0.0001]. Nevertheless, these levels were not associated with the genotypes analyzed in the present study. The results suggest that the IL-10-1082 A/G (rs1800896) G allele is associated with a decreased risk of developing pCAD. In patients and controls, the polymorphisms analyzed were associated with some cardiovascular risk factors. Although, in pCAD patients the IL-10 plasma levels were higher, they were not associated with the genotypes of the polymorphisms examined.