Analysis of the Ser786Pro Interleukin-4 Receptor α Allelic Variant in Allergic and Nonallergic Asthma and Its Functional Consequences

Asthma and other atopic disorders affect a large percentage of the population. While many factors contribute to the phenotype of asthma, there is a strong genetic predisposition. IL-4 is a central mediator of allergic inflammation. Along with IL-13, it is the major cytokine responsible for the induction of IgE synthesis. Furthermore, IL-4 acts on Th0 cells and promotes their differentiation into Th2 cells resulting in the production of more IL-4 and IL-13, thereby propagating the allergic cascade. Both IL-4 and IL-13 utilize IL-4Rα as a component of their cognate receptor complexes. Eight polymorphisms of the IL-4Rα gene resulting in amino acid changes in the coding sequence have been described, and several have been associated with asthma. The central objective of this study was to elucidate the role of the Ser786Pro polymorphism in asthma and its impact on IL-4R function. One-hundred ninety-six individuals with asthma and 53 controls were genotyped for Pro786. Pro786 occurred infrequently in the general population with an allele frequency of 1.8% and, thus, is unlikely to play a major role in atopy or asthma. The Pro786 allele frequency was 1.5% in the asthma group and 2.8% in the control group. The asthma group was subdivided into allergic and nonallergic asthma, and the Pro786 allele frequencies were 1.7 and 1.0%, respectively. The data suggested linkage disequilibrium between Ser786Pro and the Gln576Arg allele, which is associated with atopy. In order to study the impact of the polymorphism on receptor signaling function, we transfected a mouse B lymphoma cell line with the wild-type and Pro786 variants of human IL-4Rα. The Ser786Pro polymorphism in isolation did not affect IL-4R function.     

Genetic variation in CRTh2 influences development of allergic phenotypes

Background:  Allergic disorders are characterized by an increase in the Th2 cytokines IL-4, IL-5 and IL-13, produced primarily by Th2 cells. These cells are marked by the expression of CRTh2 ( c hemoattractant r eceptor-homologous molecule expressed on Th2 cells), a receptor for prostaglandin D₂. As genetic variation plays a significant role in the predisposition for allergic disorders, we investigated the influence of single nucleotide polymorphisms (SNPs) in CRTh2.
Methods:  In a large study population of German children ( n  = 4264) from the International Study of Asthma and Allergy in Children (ISAAC II), six polymorphisms in CRTh2 were genotyped. Statistical analyses were performed using single SNP and haplotype analyses.
Results:  Uncorrected associations among −6373G>A, +1431G>C and +1538A>G were observed with a number of allergic phenotypes ( P  < 0.05). After correction, association between +1431C and specific IgE to food allergens remained significant ( P  = 0.04). Associations of haplotype (H)3 (containing +1538G) with reduced risk for asthma and H2 (containing +1431C) with increased risk for specific IgE to food allergens also remained significant after correction for multiple testing ( P  = 0.004).
Conclusions:  Genetic variation within CRTh2 modifies the development of allergic sensitization and asthma in a population of German children.     

The polymorphisms of interleukin 17A (IL17A) gene and its association with pediatric asthma in Taiwanese population

Background:  The interleukin 17A ( IL17A ) gene, located on chromosome 6p and linked to asthma phenotype, is a highly potential candidate gene conferring asthma susceptibility. The purpose of this study was to investigate the genetic association between single nucleotide polymorphisms (SNPs) of IL17A and asthma in Taiwanese children.
Methods:  We selected and performed genotyping on nine SNPs that encompass the genomic region of IL17A in Taiwanese children with or without asthma. A total of 1939 subjects containing 1027 subjects in testing group and 931 subjects in validation group were recruited in this study.
Results:  After Bonferroni correction, SNP rs8193036 was found to have a weak association ( P  = 0.0074 × 9 = 0.066) in genotype frequency test. This association was confirmed by validation group. Logistic regression adjusted allergy comorbidity and gender showed a slightly weaker association.
Conclusions:  The results indicated an independent role of IL17A promoter polymorphism rs8193036 in the association with pediatric asthma in Taiwanese population.     

Genetic variation of the PSCA gene (rs2294008) is not associated with the risk of prostate cancer

Prostate stem cell antigen (PSCA) is a cell-membrane glycoprotein consisting of 123 amino acids and highly expressed in the prostate, but there have been few reports on the relationship between rs2294008 of PSCA and prostate cancer in the literature. Therefore, we evaluated the association between rs2294008 and the risk of prostate cancer. A total of 240 prostate cancer patients and 306 controls (patients with benign prostatic hyperplasia) were enrolled. Genotype analysis of rs2294008 of PSCA was performed using PCR. Logistic regression analysis was performed according to the genotype of PSCA rs2294008. We found that CT and TT genotypes were associated with an insignificant risk of prostate cancer compared with the CC genotype (P = 0.627 and 0.397, respectively). In addition, there was no significant difference in rs2294008 according to clinicopathological parameters, such as age, Gleason score, prostate-specific antigen (PSA), stage, and metastasis in prostate cancer (P > 0.05 for each). Age, Gleason score, PSA, pathologic stage, and metastasis did not modify the association between PSCA and the risk of prostate cancer (each P > 0.05 for each). Taken together, the genetic polymorphism of PSCA rs2294008 was not associated with the risk of prostate cancer. Our results suggest that rs2294008 may not play a role in prostate carcinogenesis.     

Genetic susceptibility to severe asthma with fungal sensitization

Severe asthma is problematic and its pathogenesis poorly understood. Fungal sensitization is common, and many patients with severe asthma with fungal sensitization (SAFS), used to denote this subgroup of asthma, respond to antifungal therapy. We have investigated 325 haplotype‐tagging SNPs in 22 candidate genes previously associated with aspergillosis in patients with SAFS, with comparisons in atopic asthmatics and healthy control patients, of whom 47 SAFS, 279 healthy and 152 atopic asthmatic subjects were genotyped successfully. Significant associations with SAFS compared with atopic asthma included Toll‐like receptor 3 (TLR3) (p = .009), TLR9 (p = .025), C‐type lectin domain family seven member A (dectin‐1) (p = .043), interleukin‐10 (IL‐10) (p = .0010), mannose‐binding lectin (MBL2) (p = .007), CC‐chemokine ligand 2 (CCL2) (2 SNPs, p = .025 and .041), CCL17 (p = .002), plasminogen (p = .049) and adenosine A2a receptor (p = .024). These associations differ from those found in ABPA in asthma, indicative of contrasting disease processes. Additional and broader genetic association studies in SAFS, combined with experimental work, are likely to contribute to our understanding of different phenotypes of problematic asthma.     

Association of TIM4 promoter polymorphism −1419G>A with childhood asthma in a Chinese Han population

TIM4, which is expressed on dendritic cells and macrophages, plays an important role in the proliferation of T helper type 2 (Th2) cells. Asthma, as a complex genetic disease, is thought to arise from the development of a Th2-lymphocyte-predominant immune response. To evaluate the effects of the promoter polymorphisms (-1419G>A and -1609G>A) in TIM4 on asthma susceptibility, case-control and family-based association studies were conducted by polymerase chain reaction and restriction fragment length polymorphism. Our results showed that TIM4 -1419G>A polymorphism was associated with asthma susceptibility in our study population (χ²= 9.88, P < 0.001, OR = 1.91, 95% CI 1.37–2.64). The -1419A/A and -1419A/G genotypes were observed more common in asthmatic group (6.3%, 41.8%) than in control group (1.7%, 29.3%). No significant difference was found in genotype and allele frequencies of TIM4 -1619G>A polymorphism between asthmatic and control groups. No association between the two SNPs and total serum IgE levels, lung function was observed. In conclusion, the present findings suggest that TIM4 -1419G>A polymorphism might be the genetic factor for the risk of childhood asthma in Chinese Han population.     

eotaxin-3基因多态性与变应性哮喘的相关性

目的研究eotaxin-3基因多态性与变应性哮喘的相关性。方法用聚合酶链反应-单链构象多态性-四引物聚合酶链反应-限制性酶切的方法对湖北地区汉族成人eotaxin-3＋77C／T和＋2497T／G单核苷酸多态性与哮喘易感性、嗜酸性粒细胞（eosinophil，EOS）计数以及血浆总IgE水平的相关性进行了分析。结果eotaxin-3＋2497位哮喘组与对照组G等位基因的频率，哮喘组IgE浓度及EOS数量差异有统计学意义，P值分别为0．01l、0．021和0．029；＋77位哮喘组与对照组T等位基因的频率，哮喘组IgE浓度差异无统计学意义，P值分别为0．824和0．473；＋77位哮喘组EOS数量差异有统计学意义，P值为0．044。结论eotaxin-3＋2497T／G多态性与哮喘易感性、EOS数量及IgE水平相关，＋77位C／T基因多态性与哮喘EOS数量相关。     

Cysteinyl leukotriene receptor 1 promoter polymorphism is associated with aspirin-intolerant asthma in males

BACKGROUND: Cysteinyl leukotrienes (CysLTs) play important roles in the pathogenesis of eosinophilic airway inflammation characterized by bronchoconstriction, mucus secretion and airway hyper-responsiveness via cysteinyl leukotriene receptor 1 (CysLTR1)-mediated mechanism. CysLTR1-selective antagonists have anti-bronchoconstrictive and anti-inflammatory effects in asthma, particularly aspirin-intolerant asthma (AIA). METHODS: To investigate the association of CysLTR1 with AIA development, we identified three single nucleotide polymorphisms (SNPs), -634C>T, -475A>C, -336A>G, in the 5' upstream region of CysLTR1 gene using a direct sequencing method in 105 AIA patients, 110 ASA-tolerant asthma (ATA) patients and 125 normal healthy controls (NC). RESULTS: Significant differences were observed in allele frequencies of the three SNPs within male subjects; Male AIA patients had higher frequencies of the minor alleles of these three SNPs than male control groups (P=0.03 for AIA vs. NC; P=0.02 for AIA vs. ATA). Moreover, three-SNP haplotype, ht2 [T-C-G], was associated with increased disease risk (odds ratio (OR)=2.71, P=0.03 for AIA vs. NC; OR=2.89, P=0.02 for AIA vs. ATA) in males. CysLTR1 haplotypes were also associated with altered gene expression; luciferase activity was significantly enhanced with the ht2 [T-C-G] construct in comparison with the ht1 [C-A-A] construct in human Jurkat cells (P=0.04). CONCLUSION: These results suggest that genetic variants of CysLTR1 are associated with AIA in a Korean population, and may modulate CysLTR1 expression.     

Association between genetic variations in prostaglandin E2 receptor subtype EP3 gene (Ptger3) and asthma in the Korean population

BACKGROUND: Recent investigations suggest that prostaglandin E2 (PGE2) is important in the pathogenesis of not only aspirin-intolerant asthma but also asthma unrelated to aspirin intolerance. OBJECTIVES: This study was conducted to evaluate the effects of variations in the gene coding PGE2 receptor subtype EP1-4 (Ptger1-4) on the risk of asthma in the Korean population. METHODS: Nineteen single nucleotide polymorphisms (SNPs) were selected after re-sequencing Ptger1-4 and were genotyped in 480 asthmatics and 140 healthy controls, who were randomly recruited. RESULTS: By logistic regression analyses controlling for age and sex, 1388T>C in Ptger3 was found to be significantly associated with asthma [P=0.002, odds ratio (95% confidence interval)=0.63 (0.46-0.85) in the allele model], and this remained significant after applying the Bonferroni correction. In terms of haplotype, the frequency of the C-C-A-A haplotype in Ptger3 was significantly lower in asthmatics than in healthy controls (P=0.004). Moreover, the prevalence of this haplotype was significantly lower in moderate-to-severe asthmatics than in mild asthmatics (P=0.045; mild vs. moderate and P=0.034; mild vs. severe). However, no association was found between any genetic variation in Ptger1, Ptger2, or Ptger4 and asthma. CONCLUSION: The present study demonstrated that genetic variations in Ptger3 are significantly associated with the risk and severity of asthma in the Korean population.     

Comparison of variation in frequency for SNPs associated with asthma or liver disease between Estonia,HapMap populations and the 1000 genome project populations

Allele‐specific analyses to understand frequency differences across populations, particularly populations not well studied, are important to help identify variants that may have a functional effect on disease mechanisms and phenotypic predisposition, facilitating new Genome‐Wide Association Studies (GWAS). We aimed to compare the allele frequency of 11 asthma‐associated and 16 liver disease‐associated single nucleotide polymorphisms (SNPs) between the Estonian, HapMap and 1000 genome project populations. When comparing EGCUT with HapMap populations, the largest difference in allele frequencies was observed with the Maasai population in Kinyawa, Kenya, with 12 SNP variants reporting statistical significance. Similarly, when comparing EGCUT with 1000 genomes project populations, the largest difference in allele frequencies was observed with pooled African populations with 22 SNP variants reporting statistical significance. For 11 asthma‐associated and 16 liver disease‐associated SNPs, Estonians are genetically similar to other European populations but significantly different from African populations. Understanding differences in genetic architecture between ethnic populations is important to facilitate new GWAS targeted at underserved ethnic groups to enable novel genetic findings to aid the development of new therapies to reduce morbidity and mortality.     

人类传染性疾病的遗传易感性

双生子、寄养子、家系和基于群体的关联研究表明机体遗传因素在决定人类传染性疾病的易感性中起着极为重要的作用。除少数基因已被揭示与疟疾和艾滋病的遗传易感性强烈相关外,还有其它大量基因显示与结核病、麻疯病和慢性乙型肝炎等传染性疾病的易感性相关。一些免疫相关基因可能在介导传染性疾病的遗传易感机制中担负重要角色。上述研究大多表明,绝大多数常见传染性疾病属于典型的多基因疾病(复杂性状),是致病微生物和宿主之间在长期的进化过程中交互作用的结果。后基因组时代人类基因组学的快速发展必然大大加速传染病遗传易感基因的鉴定,这有助于今后研发针对这些疾病的新的预防和治疗策略。但是,这一领域仍然面临着诸多需要克服的困难。     

Gene-expression profiles in human nasal polyp tissues and identification of genetic susceptibility in aspirin-intolerant asthma

Background Aspirin‐intolerant asthma (AIA) is a subtype of asthma induced by non‐steroidal anti‐inflammatory drugs and characterized by an aggressive mucosal inflammation of the lower airway (asthma) and the upper airways (rhinitis and nasal polyp). The lower airway lesion and the nasal polyp in AIA are postulated to have common pathogenic features involving aspirin sensitivity that would be reflected in the gene expression profile of AIA polyps. Objective This study was conducted to clarify the pathogenesis of AIA using gene expression analysis in nasal polyps, and identify genetic susceptibilities underlying AIA in a case–control association study. Methods Global gene expression of nasal polyps from nine AIA patients was examined using microarray technology in comparison with nasal polyps from five eosinophilic sinusitis (ES) patients, a related disease lacking aspirin sensitivity. Based on the AIA‐specific gene expression profile of nasal polyp, candidate genes for AIA susceptibility were selected and screened by a case–control design of 219 AIA patients, 374 non‐asthmatic control (CTR), and 282 aspirin‐tolerant asthmatic (ATA) subjects. Results One hundred and forty‐three elevated and three decreased genes were identified as AIA‐specific genes that were enriched in immune response according to Gene Ontology analysis. In addition, a k‐means‐based algorithm was applied to cluster the genes, and a subclass characteristic of AIA comprising 18 genes that were also enriched in immune response was identified. By examining the allelic associations of single nucleotide polymorphisms (SNPs) of AIA candidate genes relevant to an immune response with AIA, two SNPs, one each of INDO and IL1R2, showed significant associations with AIA (P=0.011 and 0.026 after Bonferroni's correction, respectively, in AIA vs. CTR). In AIA–ATA association analysis, modest associations of the two SNPs with AIA were observed. Conclusion These results indicate that INDO and IL1R2, which were identified from gene expression analyses of nasal polyps in AIA, represent susceptibility genes for AIA.     

A pilot exome-wide association study of age-related cataract in Koreans

Age-related cataract (ARC) is the most common cause of visual impairment and blindness worldwide. A previous study reported that genetic factors could explain approximately 50% of the heritability of cataract. However, a genetic predisposition to ARC and the contributing factors have not yet been elucidated in the Korean population. In this study, we assessed the influence of genetic polymorphisms on the risk of ARC in Koreans, including 156 cataract cases and 138 healthy adults. We conducted an exome-wide association study using Illumina Human Exome-12v1.2 platform to screen 244,770 single nucleotide polymorphisms (SNPs). No SNPs reached exome-wide significance level of association (P < 1×10?6). B3GNT4 rs7136356 showed the most significant association with ARC (P = 6.54×10?5). Two loci (MUC16 and P2RY2) among the top 20 ARC-associated SNPs were recognized as probably linked to cataractogenesis. Functions of these genes were potentially related to regulating dehydration or homeostasis of the eyes, and showed a potential association with dry eye disease. This finding suggests that mucin- and dry eye disease-related genes may play a significant role in cataractogenesis. Our study provides insight into the genetic predisposition of ARC in Koreans. Additional studies with larger sample sizes are required to confirm the results of this study.     

Genetic variation in S-nitrosoglutathione reductase (GSNOR) and childhood asthma

BACKGROUND: S-nitrosothiols are potent endogenous bronchodilators depleted in asthmatic airway lining fluid. S-nitrosoglutathione reductase (GSNOR; also known as alcohol dehydrogenase 5 or formaldehyde dehydrogenase) catalyzes the metabolism of S-nitrosoglutathione (GSNO) and controls intracellular levels of S-nitrosothiols. GSNOR knockout mice have increased lung S-nitrosothiol levels and are therefore protected from airway hyperresponsiveness after methacholine or allergen challenge. OBJECTIVE: We sought to investigate whether genetic variation in GSNOR is associated with childhood asthma and atopy. METHODS: We genotyped 5 tagging and 2 additional single nucleotide polymorphisms (SNPs) in GSNOR in 532 nuclear families consisting of asthmatic children aged 4 to 17 years and both parents in Mexico City. Atopy was determined by means of skin prick testing. RESULTS: Carrying 1 or 2 copies of the minor allele of SNP rs1,154,404 was associated with decreased risk of asthma (relative risk [RR], 0.77; 95% CI, 0.61-0.97; P = .028 for 1 copy and RR, 0.66; 95% CI, 0.44-0.99; P = .046 for 2 copies). Homozygosity for the minor allele of SNP rs28,730,619 was associated with increased risk of asthma (RR, 1.60; 95% CI, 1.13-2.26; P = .0077). Haplotype analyses supported the single SNP findings. GSNOR SNPs were not associated with the degree of atopy. CONCLUSION: This is the first study of genetic polymorphisms in GSNOR and asthma. These data suggest that genetic variation in GSNOR might play a role in asthma susceptibility. CLINICAL IMPLICATIONS: The association of GSNOR polymorphisms with asthma suggests a potential therapeutic target.     

FcRL3基因三个单核苷酸多态性与重庆汉族人群Graves病关联研究

目的 了解中国重庆地区汉族人群Fc受体样因子(Fc receptor-like proteins,FcRL3)基因启动子A/G,第2外显子C/G,第4外显子C/T多态性与Graves病(Graves disease,GD)的相关性.方法 采用聚合酶链反应限制性片段长度多态性分析方法结合直接测序技术,对重庆地区无亲缘关系的120名正常人和128例GD患者进行多态性研究,同时进行甲状腺功能和自身抗体的检测,应用Unphased1122和LDA1.0软件进行连锁不平衡和单倍型分析,用卡方检验分析基因型、等位基因和单倍型频率在GD组和对照组之间的差异.结果 GD组FcRL3基因3个多态性位点基因型和等位基因的频率与对照组相比,其差异均有统计学意义(P＜0.05).连锁不平衡分析显示启动子和第2外显子存在连锁不平衡,在构建的3个主要单倍型中,仅H2(G-G)单倍型频率GD组明显高于对照组(50.8%vs 35.8%,P＜0.05).除甲状腺疾病家族史与启动子多态性有关联(P%0.05),余临床特征与FcRL3多态性均无相关.结论 多个位点及单倍型分析提示FcRL3基因启动子A/G,第2外显子C/G,第4外显子C/T多态性可能是中国重庆地区汉族人群GD关联的危险因素.     

Association between genetic variation in the gene for death-associated protein-3 (DAP3) and adult asthma

Lung epithelium plays a central role in modulation of the lung inflammatory response, and lung repair and airway epithelial cells are targets in asthma and viral infection. Activated T lymphocytes release cytokines such as interferon-gamma (IFN-) that induce apoptosis, or programmed cell death, of damaged epithelial cells. Death-associated protein-3 (DAP3) is involved in mediating IFN--induced cell death. To assess the possible involvement of genetic variants of DAP3 with asthma, we searched for single-nucleotide polymorphisms (SNPs) in the gene and conducted a case-control study with 1,341 subjects. We found a strong association between bronchial asthma (BA) in adults (P=0.0051, odds ratio=1.87, 95% CI=1.20–2.92), whereas no association was found with childhood asthma. The tendency was more prominent in patients with higher serum total immunoglobulin E (IgE) (>250 IU/ml) (P=0.00061, odds ratio=2.40, 95% CI=1.44–4.00). DAP3 was expressed in normal bronchial epithelial cells, and the expression was induced by IFN-. These results indicated that specific variants of the DAP3 gene might be associated with the mechanisms responsible for adult BA and contribute to airway inflammation and remodeling.     

Association between ADAM33 polymorphisms and adult asthma in the Japanese population

Background ADAM33, a member of the ADAM (a disintegrin and metalloprotease) family, is a putative asthma susceptibility gene recently identified by positional cloning. It is important to know whether the association exists in ethnically diverse populations. Objective To assess whether genetic functional variants of ADAM33 relate to the susceptibility or some phenotypes in adult patients with bronchial asthma in a Japanese population. Methods We searched for single nucleotide polymorphisms (SNPs) in ADAM33 by PCR‐directed sequencing and identified 48 SNPs. Fourteen SNPs were selected with regard to the LD pattern, and genotyped by Taq‐Man and PCR–RFLP methods. We conducted an association study of ADAM33 with 504 adult asthmatic patients and 651 controls, and haplotype analyses of related variants were performed. Results Significant associations with asthma were found for the SNPs T1 (Met764Thr), T2 (Pro774Ser), S2 and V?3 (with the lowest P‐value for T1, P=0.0015; OR 0.63). We analysed the haplotype using these four polymorphisms, and found a positive association with haplotype CCTG (P=0.0024). Conclusion Our results replicate associations reported recently in other ethnic populations, and suggest that the ADAM33 gene is involved in the development of asthma through genetic polymorphisms.