Regulation of interleukin 4 gene transcription: alterations in atopic disease?

Th1 and Th2 epitopes of Cowdria polymorphic gene 1 of Ehrlichia ruminantium

Cowdria polymorphic gene 1 (cpg1, Erum2510, ERUM_RS01380) has been shown to induce 30% and 100% protection in sheep immunised by deoxyribonucleic acid (DNA) prime combined with DNA boost and DNA prime combined with protein boost, respectively, against heartwater infection via needle challenge. To localise its antigenic regions for inclusion in a multi-epitope DNA vaccine against heartwater, Erum2510 was cleaved into five overlapping subfragments. These subfragments were expressed individually in an Escherichia coli host expression system and evaluated for their ability to induce proliferative responses, Th1 and Th2 cytokines (interferon gamma [IFN-γ] and interleukin 4 [IL-4]) via enzyme-linked immunospot (ELISpot), quantitative real time polymerase chain reaction (qRT-PCR) and flow cytometry. Recombinant (r)proteins 3 and 4 were shown to induce immunodominant Th1 and Th2 immune responses characterised by the secretion of effector cytokines IFN-γ and IL-4 in addition to differential messenger ribonucleic acid (mRNA) expression of tumour necrosis factor (TNF), IL-2, IL-1, IL-18, IL-10, transforming growth factor (TGF), granulocyte-macrophage colony-stimulating factor (GM-CSF) and inducible nitric oxide synthase (iNOS). Thirty-seven overlapping synthetic peptides (16 mer) spanning the lengths of these immunodominant rproteins were synthesised and assayed. A peptide pool comprising p9 and p10 derived from rprotein 3 induced a Th1-biased immune response. A peptide pool comprising p28 and p29 derived from rprotein 4 induced a mixed Th1 and Th2 immune response characterised by secretion of IFN-γ and differential mRNA expression of IL-1, IL-2, IL-10, IL-12, iNOS, TGF, TNF and GM-CSF. Only one of the peptides (p29) induced secretion of IL-4. Phenotypic analysis showed significant activation of cluster of differentiation 8+ (CD8+), cluster of differentiation 4+ (CD4+) and B+ lymphocyte populations. Findings suggest that Erum2510 rproteins and synthetic peptides can induce both cellular and humoral immune responses, thereby implicating their importance in protection against heartwater.Contribution: This study will facilitate the design of an effective multi-epitope DNA vaccine against heartwater that will contribute to control this economically important disease in sub-Saharan Africa and beyond.

High-dimensional profiling clusters asthma severity by lymphoid and non-lymphoid status

Clinical definitions of asthma fail to capture the heterogeneity of immune dysfunction in severe, treatment-refractory disease. Applying mass cytometry and machine learning to bronchoalveolar lavage (BAL) cells, we find that corticosteroid-resistant asthma patients cluster largely into two groups: one enriched in interleukin (IL)-4+ innate immune cells and another dominated by interferon (IFN)-γ+ T cells, including tissue-resident memory cells. In contrast, BAL cells of a healthier population are enriched in IL-10+ macrophages. To better understand cellular mediators of severe asthma, we developed the Immune Cell Linkage through Exploratory Matrices (ICLite) algorithm to perform deconvolution of bulk RNA sequencing of mixed-cell populations. Signatures of mitosis and IL-7 signaling in CD206-FcεRI+CD127+IL-4+ innate cells in one patient group, contrasting with adaptive immune response in T cells in the other, are preserved across technologies. Transcriptional signatures uncovered by ICLite identify T-cell-high and T-cell-poor severe asthma patients in an independent cohort, suggesting broad applicability of our findings.

A preliminary study on the association of single nucleotide polymorphisms of interleukin 4 (IL4), IL13, IL4 receptor alpha (IL4Rα) & Toll-like receptor 4 (TLR4) genes with asthma in Indian adults

Background & objectives:

Interleukin 4 (IL4) and IL13 genes are believed to be responsible for inflammation of the airways in asthmatics. These share a common receptor component called IL4Rα which is another potentially important candidate gene linked to asthma phenotypes. Another gene Toll-like receptor 4 (TLR4) might affect the incidence or progression of asthma through the expression of proinflammatory genes. Several single nucleotide polymorphisms (SNPs) in IL4, IL13, IL4Rα and TLR4 have been reported to be linked to asthma or related phenotypes in several ethnic populations using linkage studies and association studies. However, the results have not been consistent. We investigated five SNPs (C-589T and C-33T of IL4, G+2044A of IL13, A+1902G of IL4Rα, and A+896G of TLR4) in patients with adult onset asthma to evaluate their role in manifestation and severity of asthma.

Methods:

Adult (>18 yr of age) patients with asthma (n=100) and healthy controls (n=50) were included in the study. Genotyping was performed using sequenom MassARRAY technology.

Results:

The mutant alleles of the C-589T and C-33T SNPs in the promoter region of IL4 were present in 4 per cent patients with asthma but absent from the control group suggesting that the variations in IL4 may contribute to asthma occurrence. The SNPs of other genes were seen in both controls and patients.

Interpretation & conclusions:

The results suggest the possible association between the genetic distribution of C-589T and C-33T SNPs of IL4 with asthma in Indian adults.

Role of IL-4 gene polymorphisms in HBV-related hepatocellular carcinoma in a Chinese population

Background

Interleukin-4 (IL-4) is best known as an important mediator and modulator of immune and inflammatory responses. Hepatocellular carcinoma (HCC) is a typical inflammation-related cancer, and genetic variations in the IL-4 gene may be associated with the risk of hepatitis B virus (HBV)-related HCC. However, few studies have been conducted on their association.

Objectives

To clarify the effects of IL-4 gene polymorphisms on the risk of HBV-related HCC, two common variants, −590C/T (rs2243250) and −33C/T (rs2070874), and their relationship with HBV-related disease risk were investigated in a Chinese population.

Methods

IL-4 −590C/T and −33C/T polymorphisms were examined in 154 patients with HBV-related HCC, 62 patients with HBV-induced liver cirrhosis (LC), 129 patients with chronic hepatitis B (CHB), and 94 healthy controls, using the polymerase chain reaction-restriction fragment length polymorphism method and DNA sequencing.

Results

Overall, no significant differences were observed regarding the IL-4 −590C/T and −33C/T polymorphism genotypes, alleles, or haplotypes between the patient groups and the healthy controls. However, the CC genotypes of IL-4 −590C/T and −33C/T polymorphisms were observed to be significantly associated with CHB in subgroup analysis in males [CC versus TT (OR: 4.193, 95% CI: 1.094–16.071, P = 0.037; and OR: 3.438, 95% CI: 1.032–11.458, P = 0.044) and CC versus TT+CT (OR: 4.09, 95% CI: 1.08–15.49, P = 0.038; and OR: 3.43, 95% CI: 1.04–11.28, P = 0.042)].

Conclusions

These findings suggest that genetic variants in IL-4 −590C/T and −33C/T polymorphisms may be a risk factor for CHB in Chinese males but not for HBV-related LC or HCC.

A novel mechanism for ERK-dependent regulation of IL4 transcription during human Th2-cell differentiation

We demonstrate that the mitogen-activated protein kinases extracellular signal-regulated kinase (ERK)-1 and ERK-2 have a central role in mediating T-cell receptor-dependent induction of IL4 expression in human CD4⁺ T cells. Significantly, this involved a novel mechanism wherein receptor cross-linking induced activated ERK to physically associate with a promoter element on the IL4 gene. The proximally localized ERK then facilitated recruitment of the key transcription factors necessary for initiating IL4 gene transcription. Although both ERK-1 and ERK-2 bound to the promoter, recruitment of either one alone was found to be sufficient. We thus identify a novel mode of function for ERK wherein its physical association with the promoter serves as a prerequisite for enhanceosome assembly. This unusual pathway is also indispensable for human Th2-cell differentiation.

Genetic regulation of parasite infection: empirical evidence of the functional significance of an IL4 gene SNP on nematode infections in wild primates

BACKGROUND

Susceptibility to parasite infection affects fitness-related processes, such as mate choice and survival, yet its genetic regulation remains poorly understood. Interleukin-4 (IL4) plays a central role in the humoral immune defence against nematode parasite infections, inducing IgE switch and regulation of worm expulsion from the intestines. The evolutionary and functional significance of single nucleotide polymorphisms (SNPs) in IL4-genes is known, yet empirical information on the effect of IL4 SNPs on gastro-intestinal infections is lacking. Using samples from a population of wild red-fronted lemurs (Eulemur fulvus rufus, Primates: Lemuridae), from western Madagascar, we explored the association of IL4-gene promoter polymorphisms with nematode infections and investigated a possible functional role of the IL4 polymorphism on male reproductive success.

RESULTS

Using sequence analyses of lemur DNA we detected a new SNP in the IL4 gene promoter area. Carriers of the genotype T/T showed higher nematode infection intensities than individuals of genotypes C/T and C/C. Genetic population analyses using data from more than 10 years, suggested higher reproductive success of T/T males than expected.

CONCLUSIONS

Our results suggest a regulatory effect of an IL4 gene promoter polymorphism on the intensity of parasite infections in a natural population of red-fronted lemurs, with a seemingly disadvantageous genotype represented in low frequencies. Long-term population analyses, however, point in the direction of a negative frequency-dependent association, giving a fitness advantage to the rare genotype. Due to low frequencies of the genotype in question conclusive evidence of a functional role of IL4 polymorphism cannot be drawn here; still, we suggest the use of IL4 polymorphism as a new molecular tool for quick assessment of individual genetic constitution with regard to nematode infection intensities, contributing to a better understanding of the actual components of the immune response that mediate protection against gastro-intestinal parasites.

Oct-1 is responsible for the C-33T polymorphism effect in the IL-4 promoter

IL-4 is a pleiotropic immunoregulatory cytokine secreted by Th2 subset of CD4(+) Th cells. Several transcription factors (TFs) have been determined with various degrees of certainty to bind the IL-4 promoter and to regulate its expression in human. To investigate the mechanisms responsible for phenotypic effects of the C-33T IL-4 promoter polymorphism, we performed a search of TFs binding to this promoter locus and discriminating the -33C and -33T alleles. In silico searches suggest few factors bind this region. Using an electromobility shift assay we found that Jurkat T cells contained proteins which specifically interacted with oligonucleotide probes, corresponding to the -33 region. Considerable binding differences between C and T alleles were demonstrated using competitive conditions, the proteins bound predominantly with -33C allele. We found that the transcription factor Oct-1 produced the major shifted complex. The binding of Oct-1 was not improved using activated nuclear extracts; however, we observed increases in other shifted complexes upon cell activation. We suppose that Oct-1 occupancy may compete for binding of activator proteins to closely or overlapped binding sites. Our findings suggest that the interplay between Oct-1 and unknown TFs may be responsible for the C-33T polymorphism effects.

Genetic contributions to disparities in preterm birth

Ethnic disparity in preterm delivery between African Americans and European Americans has existed for decades, and is likely the consequence of multiple factors, including socioeconomic status, environment, and genetics. This review summarizes existing information on genetic variation and its association with preterm birth in African Americans. Candidate gene-based association studies, in which investigators have evaluated particular genes selected primarily because of their potential roles in the process of normal and pathologic parturition, provide evidence that genetic contributions from both mother and fetus account for some of the disparity in preterm births. To date, most attention has been focused on genetic variation in pro- and anti-inflammatory cytokine genes and their respective receptors. These genes, particularly the pro-inflammatory cytokine genes and their receptors, are linked to matrix metabolism because these cytokines increase expression of matrix degrading metalloproteinases. However, the role that genetic variants that are different between populations play in preterm birth (e.g. the SERPINH1 - G56 SNP) cannot yet be quantified. Future studies based on genome wide association or admixture mapping may reveal other genes that contribute to disparity in prematurity.

Effect of cytokine genotypes on the hepatitis B virus-hepatocellular carcinoma association

BACKGROUND

In Southern Guangxi, China, chronic infection with the hepatitis B virus (HBV) acquired during the perinatal period from carrier mothers is a primary cause of hepatocellular carcinoma. However, only a minority of HBV carriers eventually develop hepatocellular carcinoma. The authors hypothesized that cytokine genotypes may be important codeterminants of the risk of HBV-related hepatocellular carcinoma.

METHODS

The authors examined the correlation between polymorphisms in T-helper 1 (Th1) and Th2 cytokine genes among a group of 250 patients with incident hepatocellular carcinoma (cases) and a group of 250 hospital controls who were matched individually to the index case by age, gender, ethnicity, residence, and month of hospital admission in the city of Nanning, Guangxi, China.

RESULTS

Relative to the putative high-activity genotypes, each individual low-activity genotype of interferon gamma, interleukin 12 (IL12), and IL18 was associated with a statistically nonsignificant increase (40-60%) in the risk of hepatocellular carcinoma. This risk increased with increasing numbers of low-activity Th1 genotypes after adjusting for potential confounders (2-sided P value for trend=0.04). Conversely, individual Th2 (IL4, IL10) low-activity genotypes were associated with a statistically nonsignificant reduced risk of hepatocellular carcinoma. This risk decreased with increasing number of low-activity Th2 genotypes after adjusting for potential confounders (2-sided P value for trend=0.01). Individuals who had the maximum number (i.e., 3) of low-activity Th1 genes and the minimum number (i.e., 0) of low-activity Th2 genes showed a relative risk of 20.0 (95% confidence interval, 1.7-235.0).

CONCLUSIONS

Diminished cell-mediated immune response, which is controlled genetically, appeared to be an important risk determinant of HBV-related hepatocellular carcinogenesis.

Interleukin-4 and -10 gene polymorphisms and spontaneous preterm birth in multifetal gestations

OBJECTIVE

The purpose of this study was to determine the relationship between maternal and fetal carriage of different alleles of interleukin-4 and -10 genes and pregnancy outcome in multifetal gestations.

STUDY DESIGN

Buccal swabs from mother-infant pairs of 73 multifetal gestations were assayed for polymorphisms at position -590 of the interleukin-4 gene and position -1082 of the interleukin-10 gene. Pregnancy outcome data were obtained subsequently.

RESULTS

Spontaneous preterm birth occurred in 29 of the pregnancies (39.7%). A higher frequency of the interleukin-4 T allele was found among mothers with spontaneous preterm birth compared with mothers without spontaneous preterm birth (36.2% vs 18.2%; P=.02; odds ratio, 2.6; 95% CI, 1.1-5.9). Moreover, 20.7% of mothers who had spontaneous preterm birth were homozygous for the interleukin-4 T allele, as opposed to only 2.3% of mothers who did not have a spontaneous preterm birth (P=.01; odds ratio, 11.2; 95% CI, 1.2-69.5). Similarly, in 55.2% of the pregnancies that were complicated by spontaneous preterm birth, 2 fetuses carried the interleukin-4 T allele, compared with only 29.5% of the pregnancies that were not complicated by spontaneous preterm birth (p<.05; odds ratio, 2.9; 95% CI, 1.0-8.8). There was no relationship between mother and infant IL-10 genotype and spontaneous preterm birth.

CONCLUSION

Maternal and fetal carriage of the interleukin-4 T allele is associated with an increased risk of spontaneous preterm birth in multifetal gestations.

Polymorphisms in IL-4Rα Correlate with Airways Hyperreactivity, Eosinophilia, and Ym Protein Expression in Allergic IL-13−/− Mice

The development of airways hyperreactivity in allergic IL-13(-/-) mice is controversial and appears to correlate with the number of times that the original 129 x C57BL/6 founder strain has been crossed to the BALB/c background. In this investigation, we compared allergic responses in founder IL-13(-/-) mice crossed for either 5 (N5) or 10 (N10) generations to BALB/c mice. Whereas allergic N5 IL-13(-/-) mice developed airways hyperreactivity, tissue eosinophilia, elevated IgE, and pulmonary expression of Ym proteins, these processes were attenuated in N5 IL-13(-/-) mice treated with an IL-4-neutralizing Ab, and in N10 IL-13(-/-) mice. These data showed that IL-4 was more effective in regulating allergic responses in N5 IL-13(-/-) mice than in N10 IL-13(-/-) mice. To elucidate the mechanism associated with these observations, we show by restriction and sequence analysis that N5 IL-13(-/-) mice express the C57BL/6 form of IL-4Ralpha and N10 IL-13(-/-) mice express the BALB/c form. Despite the near identical predicted molecular mass of these isoforms, IL-4Ralpha from N5 IL-13(-/-) mice migrates with a slower electrophoretic mobility than IL-4Ralpha from N10 IL-13(-/-) mice, suggesting more extensive posttranslational modification of the N5 form. The Thre(49)Ile polymorphism in the extracellular domain of BALB/c IL-4Ralpha has been demonstrated to disrupt N-linked glycosylation of Asn(47) and increase the dissociation rate of the IL-4Ralpha/IL-4 interaction. Collectively, these data show that polymorphisms in IL-4Ralpha, which have been shown to affect the interaction with IL-4, correlate with the ability of IL-4 to regulate allergic responses in IL-13(-/-) mice.

Positive Selection on a Human-Specific Transcription Factor Binding Site Regulating IL4 Expression

A single nucleotide polymorphism in the promoter of the multifunctional cytokine Interleukin 4 (IL4) affects the binding of NFAT, a key transcriptional activator of IL4 in T cells. This regulatory polymorphism influences the balance of cytokine signaling in the immune system, with important consequences-positive and negative-for human health. We determined that the NFAT binding site is unique to humans; it arose by point mutation along the lineage separating humans from other great apes. We show that its frequency distribution among human subpopulations has been shaped by the balance of selective forces on IL4's diverse roles. New statistical approaches, based on parametric and nonparametric comparisons to neutral variants typed in the same individuals, indicate that differentiation among subpopulations at the IL4 promoter polymorphism is too great to be attributed to neutral drift. The allele frequencies of this binding site represent local adaptation to diverse pathogenic challenges; disease states associated with the common derived allele are side-effects of positive selection on other IL4 functions.