ADAM33 polymorphism: association with bronchial hyper-responsiveness in Korean asthmatics

ADAM33's Role in Asthma Pathogenesis: An Overview

Asthma is a complex chronic respiratory disease characterized by airway hyperresponsiveness, inflammation, and obstruction. Many genes have been identified as associated with asthma but none with such substantial significance as the ADAM33 gene due to its role in airway remodeling and bronchial hyperresponsiveness. This review summarizes the current knowledge on the genetic and functional aspects of ADAM33 in asthma pathogenesis. We highlight its genetic variants associated with asthma susceptibility and severity, as well as the functional effects of ADAM33 on airway remodeling, smooth muscle cell proliferation, and its interplay with environmental factors. Additionally, we discuss the potential clinical implications of ADAM33 as a therapeutic target for asthma management.

Polymorphism in ADAM33 gene associated with asthmatics in West Bengal, India - An investigation by in-silico analysis

Introduction

Asthma is one of the common chronic polygenic inflammatory diseases. Genome wide association studies have identified ADAM33 as an asthma candidate gene. The present study investigated possible association of rs2280090 (T1), rs2280091 (T2) and rs3918396 (S1) single nucleotide polymorphisms (SNPs) of ADAM33 with aeroallergen induced asthma in West Bengal population, India. In addition, in-silico analysis was performed to find out changes in protein function.

Methods

Forced expiratory volume in 1 second (FEV1)/Forced vital capacity (FVC), peak expiratory flow rate (PEFR) were assessed using spirometry in 1039 participants. Allergic sensitivity of 619 spirometry positive asthma patients was assessed by skin prick test (SPT) against 22 aeroallergens. For genotyping of T1, T2, and S1 SNPs in 540 allergic asthma patient and 420 control subjects, polymerase chain reaction-based restriction fragment length polymorphism was performed. Total Immunoglobulin-E (IgE) level was measured in both patients and controls. ADAM333 haplotype blocks were constructed using Haploview software v.4.2. Structural model of transmembrane and cytoplasmic domains of ADAM33 was generated using RaptorX. Protein-protein interaction was analysed using the STRING server.

Results

Highest number of patient sensitivity was observed towards Cocos nusifera (n = 215) and Dermatophagoides farinae (n = 229). Significant difference in sensitivity was observed between child and late adult (P = 0.03), child and early adult (P = 0.02), adolescent and late adult (P = 0.02) and adolescent and early adult (P = 0.01). Genotypic frequencies differed significantly between patients and controls (P < 0.05). rs2280090 GG, rs2280091GG and AG genotype, and rs3918396 AA carried significant risk for asthma (P = 0.02, P = 0.008, P = 0.04, P = 0.01 respectively). ADAM33 T1, T2, and S1 polymorphisms were in high Linkage Disequilibrium (D = 0.98). Haplotype consisting of rs2280090G, rs2280091G and rs3918396A alleles were found significantly higher in patient population in comparison with controls (OR = 2.03). IgE level differed significantly among different genotypes for T1, T2, and S1 SNPs analysed in pair (P < 0.0001). FEV1/FVC ratio differed significantly among different genotypes for T1, T2 and S1 SNPs analysed in pair (P < 0.0001). Significant difference of FEV1/FVC was also found between GGA and AAG haplotype (P < 0.0001). In-silico analysis revealed T1 and T2 polymorphisms are located in cytoplasmic domain of ADAM33 may cause bronchial smooth muscle cell mobility and cellular hyperplasia as well as cytoskeletal remodelling by altered interaction with different cytoplasmic proteins found by string analysis.

Conclusion

Present study showed significant association of T1, T2, and S1 polymorphisms of ADAM33 with aeroallergen-induced asthma in West Bengal, India. These polymorphisms may be used as prognostic markers and possible targets for therapeutics in future.

Association between ADAM33 Single-Nucleotide Polymorphisms and Treatment Response to Inhaled Corticosteroids and a Long-Acting Beta-Agonist in Asthma

ADAM33 has been linked to airway structural changes in patients with asthma, leading to airway hyperresponsiveness, narrowing, and ultimately poor treatment responsiveness. This study aimed to evaluate the genetic association of ADAM33 SNPs with asthma, disease severity, and treatment responsiveness to ICS+LABA in the South Indian population. In this case-control study (486 controls and 503 cases), we performed genotyping using MassArray for six SNPs of ADAM33, namely rs2280091, rs2787094, rs3918396, rs67044, rs2853209, and rs3918392. We studied the association with asthma and treatment responsiveness to ICS+LABA, using genotype, allele frequency distribution, and haplotype analysis. A significant clinical finding of the study was that certain patients in the disease severity group (moderate and mild) showed poor or no improvement after a three-month follow-up of regular ICS+LABA therapy. Of the studied ADAM33 SNPs, rs2853209 showed an association with asthma. The further analysis of asthma patients according to disease severity suggested an association between moderate disease and the minor allele "T" for rs2853209. The homozygous minor allele of SNP rs2787094 was found to be associated with poorer lung function and the least lung-function improvement after three months of ICS+LABA therapy. The haplotype analysis of six SNPs showed a significant association between the rs2853209 and rs3918396 blocks and asthma. ADAM33 gene polymorphism has clinical relevance in terms of disease association and response to treatment. SNP rs2853209 seemed most relevant to asthma, and SNP rs2787094 could be a genetic marker for predicting response to ICS+LABA therapy in the study population.

The Association of IgE Levels with ADAM33 Genetic Polymorphisms among Asthmatic Patients

Total serum immunoglobulin E (IgE) is elevated in multiple allergic diseases and is considered a good predictor of atopy. Several studies have been performed on the association of IgE levels with the polymorphism of the ADAM33 gene in asthmatic patients. The aim of this study was to determine whether there is an association between IgE levels and the genetic polymorphisms of the ADAM33 gene (T1, T2, T + 1, V4, S1, S2, and Q-1) in both healthy and asthmatic patients among Jordanians. The clinical data were collected for this case–control study from 267 asthmatic patients and 225 control subjects. Seven genetic polymorphisms (T1, T2, T + 1, V4, S1, S2, and Q-1) of the gene ADAM33 were analyzed using the polymerase chain reaction/restriction fragment length polymorphism method. The minor alleles (G) of T1, (A) of T2, T + 1, and (G) of V4 polymorphisms were associated with a significant increase in total serum IgE levels in adults but not children. The V4 genetic polymorphism, however, showed a significant association with IgE levels in both adults and children. The S1 polymorphism was significantly associated with the codominant module only in the adults. The S2 polymorphism showed a significant association (p-value < 0.05) in both codominant and recessive models. However, in the dominant model for both pediatric control and asthmatic patients, the association between the IgE and S2 polymorphism was insignificant (p-value = 0.7271 and 0.5259, respectively). This study found a statistically significant association between multiple ADAM33 genetic polymorphisms and IgE levels. Such findings add to the growing evidence that the ADAM33 gene has a major impact on IgE levels among asthmatic patients of Jordanian origin.

Haplotype analysis of ADAM33 polymorphisms in asthma: A pilot study

Background & objectives

ADAM33 is implicated as a potentially strong candidate gene for asthma and bronchial hyper-responsiveness. Many polymorphisms of ADAM33 have been studied along with ADAM33 expression in various cells of the lungs. Haplotype analysis also showed association with asthma in different populations across the world. Therefore, the aim of this study was to perform a comprehensive screening of ADAM33 polymorphisms in adult patients with asthma.

Methods

Thirty five polymorphisms of ADAM33 were genotyped in 55 patients with asthma and 53 controls. The association of single nucleotide polymorphisms (SNPs) and haplotypes with phenotypes of asthma was analysed.

Results

The genotype, minor allele frequency, odds ratio and Hardy-Weinberg equilibrium did not show any significant difference among cases and controls. No association was found between SNPs of ADAM33 with the severity of asthma. Correlation analysis of ADAM33 SNPs to the phenotypes, based on clinical variables and allergen sensitization, did not show significant difference. Haplotype analysis showed that rs2280090 and rs2280091 were associated with asthma in the patient group.

Interpretation & conclusions

Haplotype analysis showed an association of the two SNP variations with asthma. These SNPs lead to amino acid change and are prone to phosphorylation, which may affect expression levels and protein function of ADAM33 and asthma susceptibility.

Association between ADAM33 polymorphisms and asthma risk: a systematic review and meta-analysis

Background

Asthma is a common complex chronic, inflammatory polygenic disease with heterogeneous manifestations, affecting individuals of all age groups and posing an immense burden on healthcare resources. A number of studies have identified the association between a disintegrin and metalloprotease 33 (ADAM33) polymorphisms and asthma risk, however, the results still remain inconclusive. The objective of the present study was to identify the effect of ADAM33 variants in asthma susceptibility.

Methods

Eligible case-control studies published between January 2000 and June 2018 was searched and retrieved from online electronic databases. The odds ratio (OR) with its 95% confidence interval (CI) was employed to calculate the effect.

Results

A total of 63 case-control studies were finally screened out, including 13,280 asthma patients and 13,340 controls. Eleven SNPs of ADAM33 gene were identified. Our results detected a significant association between ADAM33 T2, Q1, F + 1 and AA genotype of T + 1 polymorphisms and asthma risk in total population. Subgroup analysis by ethnicities showed that the alleles and genotypes of T2, Q1 and F + 1 polymorphisms were associated with asthma susceptibility among Asian populations, while V4 polymorphism was associated with asthma among Caucasian populations. Subgroup analysis by ages showed that T2, F + 1 and ST + 4 polymorphisms were associated with childhood asthma, while Q1 and V4 polymorphisms were associated with asthma risk in adults. Subgroup analysis by asthma severity showed that only the G allele of ADAM33 T1 polymorphism was associated with the severity of asthma when compared with the controls. In addition, T2, Q1 and F + 1 polymorphisms of ADAM33 were significantly associated with increased the asthma risk in Chinese asthma patients.

Conclusions

Our results found that T2, Q1 and F + 1 polymorphisms of ADAM33 gene might contribute to asthma risk. Future well-designed case-control studies with large population and more ethnicities are still needed to estimate the association.

Locked Nucleic Acid Gapmers and Conjugates Potently Silence ADAM33, an Asthma-Associated Metalloprotease with Nuclear-Localized mRNA

Two mechanisms dominate the clinical pipeline for oligonucleotide-based gene silencing, namely, the antisense approach that recruits RNase H to cleave target RNA and the RNAi approach that recruits the RISC complex to cleave target RNA. Multiple chemical designs can be used to elicit each pathway. We compare the silencing of the asthma susceptibility gene ADAM33 in MRC-5 lung fibroblasts using four classes of gene silencing agents, two that use each mechanism: traditional duplex small interfering RNAs (siRNAs), single-stranded small interfering RNAs (ss-siRNAs), locked nucleic acid (LNA) gapmer antisense oligonucleotides (ASOs), and novel hexadecyloxypropyl conjugates of the ASOs. Of these designs, the gapmer ASOs emerged as lead compounds for silencing ADAM33 expression: several gapmer ASOs showed subnanomolar potency when transfected with cationic lipid and low micromolar potency with no toxicity when delivered gymnotically. The preferential susceptibility of ADAM33 mRNA to silencing by RNase H may be related to the high degree of nuclear retention observed for this mRNA. Dynamic light scattering data showed that the hexadecyloxypropyl ASO conjugates self-assemble into clusters. These conjugates showed reduced potency relative to unconjugated ASOs unless the lipophilic tail was conjugated to the ASO using a biocleavable linkage. Finally, based on the lead ASOs from (human) MRC-5 cells, we developed a series of homologous ASOs targeting mouse Adam33 with excellent activity. Our work confirms that ASO-based gene silencing of ADAM33 is a useful tool for asthma research and therapy.

ADAM33 gene polymorphisms identified to be associated with asthma in a Chinese Li population

A disintegrin and metalloprotease 33 (ADAM33) is an asthma susceptibility gene that has been proven to be present in certain human populations. The Li population is a minority ethnic group, most of whom maintain a distinctive lifestyle on Hainan Island in southern China. To the best of our knowledge, no previous study has established whether ADAM33 polymorphisms are associated with asthma in the Li population. Therefore, the ADAM33 polymorphisms in a Li population were investigated in the present study. A total of 150 asthma patients and 100 healthy subjects were enrolled in the present study, and their DNA samples were evaluated to analyze eight single-nucleotide polymorphisms (SNPs) on the ADAM33 gene. Asthma patients were subcategorized into low and high severity groups, and their SNP data were compared with the data of the control subjects. Single-marker and haplotype association was analyzed to demonstrate the association between ADAM33 SNPs and asthma using multiple genetic statistic tests. The results indicated significant differences in allele frequencies at the SNPs rs44707/T2 (P=0.008), rs2787094/V4 (P=0.028) and rs2280089/T+1 (P=0.021) between asthma patients and control subjects. The SNP rs44707/T2 was also found to be associated with the high severity group (P=0.024), although SNPs rs2787094/V4 were associated with the low severity group (P=0.019). Two haplotypes, GGAGAGT and GAAGGGT, were significantly associated with asthma (P=0.003 and 0.008, respectively). To the best of our knowledge, this is the first time that SNP rs2280089/T+1 has been reported to be associated with asthma in an Asian population. These data confirm that ADAM33 polymorphisms are associated with asthma susceptibility in the Li population and confirm the uniqueness of the Li minority population within China.

Genetic variants of ADAM33 are associated with asthma susceptibility in the Punjabi population of Pakistan

OBJECTIVE

A disintegrin and metalloproteinase 33 (ADAM33) gene has been considered as an asthma susceptibility gene due to its possible role in airway remodeling, abnormal cell proliferation, and differentiation. Association of this gene with asthma has been reported in several genetic studies on various populations. The current study aims to evaluate the association of ADAM33 gene polymorphisms with the risk of asthma in the Punjabi population of Pakistan.

METHOD

A total of 101 asthma patients and 102 age-matched healthy controls from Lahore, a city in Punjab, were recruited. ADAM33 single nucleotide polymorphisms (SNPs) T + 1[rs2280089], T2[rs2280090], T1[rs2280091], ST + 5[rs597980], ST + 4[rs44707], S2[rs528557], Q - 1[rs612709], and F + 1[rs511898] were genotyped in both patients and controls using single base extension and capillary electrophoresis-based genetic analyzer. The basic allelic and genotypic model was analyzed for association of the SNPs with asthma using SHEsis software. Haploview software was used to calculate pairwise linkage disequilibrium (LD) among six of the genotyped SNPs.

RESULTS

Of the 8 SNPs genotyped, only S2[rs528557] showed significant association with asthma (Allele p = 0.0189, Genotype p = 0.021). SNPs T + 1[rs2280089], T2[rs2280090], T1[rs2280091], ST + 4[rs44707], S2[rs528557], and Q - 1[rs612709] were found to be in moderate to strong LD. The significantly higher frequency of haplotype "AAGTCG" in healthy controls suggests a protective effect against asthma risk in the studied population (p = 0.0059).

CONCLUSION

These findings suggest that genetic variants of ADAM33 gene may play important roles in asthma susceptibility in the Punjabi population of Pakistan.

A disintegrin and metalloprotease 33 polymorphism association with COPD in long-term tobacco smokers of the ethnic Kashmiri population of India

Background:

Chronic obstructive pulmonary disease (COPD) is characterized by an interaction of various environmental influences especially cigarette smoking and genetic determinants. The prevalence of this disease is ever increasing and characterization of the genetic determinants of the disease has been undertaken globally. The ‘A disintegrin and metalloprotease 33’ (ADAM 33) gene is one candidate gene that has been studied.

Objective:

Our objective was to investigate whether single nucleotide polymorphisms in ADAM33 gene are associated with COPD in long-term tobacco smokers in the ethnic Kashmiri population of northern India.

Materials and Methods:

This was a randomized case-control study, which included 78 stable COPD (GOLD stage11-IV) patients, who were compared with 77 age- and sex-matched long-term tobacco smokers (>20 pack years) without any evidence of COPD. Polymorphic analysis for three single nucleotide polymorphisms (SNPs), (T1, T2, and Q1) of the ADAM33 gene was done by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) followed by sequencing. The data were analyzed by descriptive statistics and comparative evaluation was done by parametric/non-parametric tests.

Results:

The analysis of the T1, T2, and Q1 SNPs, revealed that the frequencies of the T2GG, T1GG, and the Q1AG genotypes were significantly higher in patients with COPD in comparison with the controls (P < 0.001). Similarly, the T1G and T2G allele frequency was higher in the patients than in the controls (p = 0.177 and 0.43, respectively).

Conclusion:

Three SNPs of the ADAM33 gene were significantly associated with COPD in the Kashmiri population of India. This study establishes the possible role of ADAM33 SNPS in the causation of COPD. Further studies across different geographical areas in the country will unravel the contribution of this gene in the causation of COPD in India.

An ADAM33 polymorphism associates with progression of preschool wheeze into childhood asthma: a prospective case-control study with replication in a birth cohort study

BACKGROUND

The influence of asthma candidate genes on the development from wheeze to asthma in young children still needs to be defined.

OBJECTIVE

To link genetic variants in asthma candidate genes to progression of wheeze to persistent wheeze into childhood asthma.

MATERIALS AND METHODS

In a prospective study, children with recurrent wheeze from the ADEM (Asthma DEtection and Monitoring) study were followed until the age of six. At that age a classification (transient wheeze or asthma) was based on symptoms, lung function and medication use. In 198 children the relationship between this classification and 30 polymorphisms in 16 asthma candidate genes was assessed by logistic regression. In case of an association based on a p<0.10, replication analysis was performed in an independent birth cohort study (KOALA study, n = 248 included for the present analysis).

RESULTS

In the ADEM study, the minor alleles of ADAM33 rs511898 and rs528557 and the ORMDL3/GSDMB rs7216389 polymorphisms were negatively associated, whereas the minor alleles of IL4 rs2243250 and rs2070874 polymorphisms were positively associated with childhood asthma. When replicated in the KOALA study, ADAM33 rs528557 showed a negative association of the CG/GG-genotype with progression of recurrent wheeze into childhood asthma (0.50 (0.26-0.97) p = 0.04) and no association with preschool wheeze.

CONCLUSION

Polymorphisms in ADAM33, ORMDL3/GSDMB and IL4 were associated with childhood asthma in a group of children with recurrent wheeze. The replication of the negative association of the CG/GG-genotype of rs528557 ADAM33 with childhood asthma in an independent birth cohort study confirms that a compromised ADAM33 gene may be implicated in the progression of wheeze into childhood asthma.

Association between ADAM33 polymorphisms and susceptibility with adult and childhood asthma among Jordanians

Disintegrin and metalloprotease 33 (ADAM33) have been associated with childhood and adult asthma in many populations. ADAM33 mutations might predispose to altered lung function in early infancy. In this study, we investigated the association between single-nucleotide polymorphisms in ADAM33 and the incidence of adult and childhood asthma among Jordanians. One hundred seven pediatric asthmatic patients, 115 healthy pediatric patient controls, 160 adult asthmatic patients, and 110 healthy adults were enrolled in this study. ADAM33 polymorphisms were genotyped using the polymerase chain reaction/restriction fragment length polymorphism method. A strong association between the V4 genotype and incidence of childhood asthma was found. In the single-locus analyses of asthma risk, V4 C/G single nucleotide polymorphism (SNP) showed a trend toward significance with p=0.07. Interestingly, the CC homozygous mutant genotype frequency was significantly higher in asthmatic subjects (15.9%) than in control subjects (2.6%), resulting in an odds ratio of 7.05. In adult cases, S2, the F+1 and Q-1 genotype showed a significant association (p≤0.05) with the incidence of asthma. Two haplotypes also exhibited a significant association with asthma (p≤0.05). In conclusion, the findings of this study confirm the already reported association between V4 SNP and the incidence of childhood asthma as well as between S2, F+1, and Q-1 SNPs and the incidence of adult asthma in several populations.

Association between genetic polymorphisms in the ADAM33 gene and asthma risk: a meta-analysis

The aim of this study was to evaluate the associations between the rs3918396 G>A and rs528557 C>G polymorphisms in the disinterring and metalloproteinase domain 33 (ADAM33) gene and asthma risk. We searched CISCOM, CINAHL, Web of Science, PubMed, Google Scholar, EBSCO, Cochrane Library, and CBM databases from inception through August 1st, 2013 without language restrictions. Meta-analysis was performed using the STATA 12.0 software. Crude odds ratios (ORs) with their 95% confidence intervals (95% CI) were calculated. Thirteen case-control studies were included with a total of 7104 asthma patients and 8172 healthy controls. Our meta-analysis results revealed that ADAM33 rs528557 C>G polymorphism was associated with an increased risk of asthma (all p<0.05). However, we found no correlation between the ADAM33 rs3918396 G>A polymorphism and asthma risk (all p>0.05). Subgroup analysis by ethnicity indicated that the ADAM33 rs528557 C>G polymorphism might be strongly associated with an increased risk of asthma among both Caucasian and Asian populations (All p<0.05). No significant association was found between the ADAM33 rs3918396 G>A polymorphism and the risk of asthma among the studied ethnicities (All p>0.05). The present meta-analysis suggests that the ADAM33 rs528557 C>G polymorphism may contribute to susceptibility to asthma. Thus, the ADAM33 rs528557 C>G polymorphism may be utilized as a biomarker for early diagnosis of asthma.

Associations of genetic variants in ADAM33 and TGF-β1 genes with childhood asthma risk

The aim of the present study was to explore the associations of genetic variants in the ADAM33 and TGF-β1 genes with the risk of childhood asthma. A total of 299 asthmatic children and 311 healthy controls were recruited in the hospital-based case-control study. The asthmatic subjects were further divided into mild and severe groups according to disease severity. Single-nucleotide polymorphisms (SNP) at ADAM33 V4, T2, S2 and T1, and TGF-β1 C-509T and T869C were selected and detected with PCR-RFLP. The associations of the SNPs with asthma risk and severity were analyzed. The associations between the haplotypes of ADAM33 and TGF-β1 were also evaluated. Compared with the GG genotype, the GC and CC genotypes at V4 were associated with an increased asthma risk in children and the ORs were 2.92 and 10.56, respectively. Compared with the CC genotype, the CT/TT genotype at C-509T was associated with an increased asthma risk and the OR was 2.26. Subsequent to stratification by asthma severity, compared with the V4 GG genotype, it was found that the CG and CC genotypes were associated with a mild asthma risk and the ORs were 3.00 and 5.99, respectively. The SNP at C-509T (CT/TT vs. CC) was associated with mild asthma (OR=2.34), whereas a marginally significant association was detected between the SNP (CT/TT vs. CC) and severe asthma risk (OR=2.19). The haplotype analysis revealed that, compared with the GGCA haplotype of ADAM33, significant associations of the haplotypes of CGCG, CGGA, GACA, GACG and GAGA with asthma risk were observed, and the ORs were 31.12, 12.24, 4.73, 30.85 and 4.83, respectively. No significant association was detected between the TGF-β1 haplotypes and asthma risk. The genetic variants at V4 and C-509T had the potential to modify the childhood asthma risk and the associations showed no notable difference with the disease severity. Thus, ADAM33 haplotypes provided more useful information in the prediction of asthma risk.

Association study on ADAM33 polymorphisms in mite-sensitized persistent allergic rhinitis in a Chinese population

Background

The ADAM33 gene has been identified as a potentially important asthma candidate gene and polymorphisms in this gene have been shown to be associated with asthma and seasonal allergic rhinitis.

Objective

To assess whether the ADAM33 polymorphisms are associated with persistent allergic rhinitis (PER) due to house dust mites in a Chinese population.

Methods

In a hospital-based case-control study of 515 patients with mite-sensitized PER and 495 healthy controls, we genotyped seven single nucleotide polymorphisms (SNPs) in ADAM33. Serum levels of eosinophil cationic protein, total IgE and allergen-specific IgE against Dermatophagoides pteronyssinus and Dermatophagoides farinae were measured by the ImmunoCAP assays.

Results

In the single-locus analysis, three polymorphisms, rs3918392 (F1), rs528557 (S2) and rs2787093, were significantly associated with mite-sensitized PER. SNP S2 was associated with significantly increased risk both of asthmatic and nonasthmatic mite-sensitized PER. In the combined genotypes analysis, individuals with 2–4 risk alleles had a significantly higher risk of mite-sensitized PER (adjusted OR = 1.99, 95% CI = 1.50–2.62) than those with 0–1 risk alleles. Haplotype-based association analysis revealed that the ACAGCCT haplotype might have potential to protect against mite-sensitized PER (adjusted OR = 0.67; 95% CI = 0.49–0.90).

Conclusions

Polymorphisms in the ADAM33 gene may contribute to susceptibility of mite-sensitized PER in this Chinese population.

Association of ADAM33 gene polymorphisms with COPD in the Mongolian population of China

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a respiratory disorder with increasing prevalence and mortality, influenced by both environmental and genetic factors. ADAM33 gene has been found to be associated with asthma, declined lung function and COPD.

AIM

The aim of this study was to find out if SNPs in ADAM33 (V4, T+1, T1, T2, S1, S2, Q-1 and F+1) play any role in genetic susceptibility to COPD in the Mongolian population of China.

SUBJECTS AND METHODS

Two hundred and fifteen Mongolian COPD patients and 223 Mongolian healthy individuals were recruited for the study. Eight polymorphic loci (V4, T+1, T2, T1, S2, S1, Q-1, and F+1) of ADAM33 were selected for genotyping. Genotyping was carried out using the Polymerase Chain Reaction and Restriction Fragment Length polymorphism (PCR-RFLP) method.

RESULTS

Seven SNPs in ADAM33 were associated with COPD (T+1, p = 0.014; T2, p = 0.018; T1, p = 0.048; S2, p = 0.003; S1, p = 0.000; Q-1, p = 0.000 and F+1, p = 0.000), even after Bonferroni correction, SNPs S2, S1, Q-1 and F+1 remained significant. Haplotype analysis showed that the frequencies of haplotype H1 (GGAGGGT), H5 (GGAGGGC) and H10 (GGGGAGT) were significantly higher in the COPD group than in the control group (p = 0.002, 0.031 and 0.009, respectively). In contrast, the haplotype H11 (GGACAGC) was more common in the control group than in the case group (p = 0.015).

CONCLUSIONS

Seven SNPs in ADAM33 were associated with COPD in the Mongolian population of China.

ADAM33 protein expression and the mechanics of airway smooth muscle cells are highly correlated in ovalbumin-sensitized rats

A disintegrin and metalloproteinase 33 (ADAM33) has been identified as an asthma susceptibility gene; however, the role of ADAM33 in the pathogenesis and progression of asthma remains to be elucidated. As ADAM33 is predominantly expressed in airway smooth muscle cells (ASMCs), it is feasible to investigate whether ADAM33 protein expression is correlated with ASMC mechanics that are ultimately responsible for airway hyperresponsiveness in asthma. To determine this, Sprague Dawley rats were sensitized with ovalbumin (OVA) for up to 12 weeks to simulate asthma symptoms. Subsequently, ASMCs were isolated from the rats and cultured in vitro. The protein expression of ADAM33 and cytoskeletal proteins (including F‑actin and vinculin), cell stiffness and contractility, as well as traction force were measured. The results demonstrated that compared with the non‑sensitized rats, the protein expression of ADAM33 in ASMCs from the OVA‑sensitized rats increased in a time‑dependent manner, reaching a maximum level at 4 weeks of sensitization and gradually subsiding as OVA sensitization continued (P<0.001). The cell stiffness, traction force and expression of vinculin and F‑actin changed similarly, resulting in a positive correlation with ADAM33 protein expression (Pearson's correlation coefficient, 0.864, 0.716, 0.774 and 0.662, respectively; P=0.1‑0.3). The in vivo results of OVA‑induced ADAM33 protein expression and its association with the mechanics of ASMCs suggested that ADAM33 is a mediator of ASMC dysfunction in asthma, and may provide a rationale for the therapeutic targeting of ADAM33 in the treatment of asthma.

Unraveling the genetic basis of aspirin hypersensitivity in asthma beyond arachidonate pathways

Although aspirin-exacerbated respiratory disease (AERD) has attracted a great deal of attention because of its association with severe asthma, it remains widely under-diagnosed in the asthmatic population. Oral aspirin challenge is the best method of diagnosing AERD, but this is a time-consuming procedure with serious complications in some cases. Thus, development of non-invasive methods for easy diagnosis is necessary to prevent unexpected complications of aspirin use in susceptible patients. For the past decade, many studies have attempted to elucidate the genetic variants responsible for risk of AERD. Several approaches have been applied in these genetic studies. To date, a limited number of biologically plausible candidate genes in the arachidonate and immune and inflammatory pathways have been studied. Recently, a genome-wide association study was performed. In this review, the results of these studies are summarized, and their limitations discussed. In addition to the genetic variants, changes in methylation patterns on CpG sites have recently been identified in a target tissue of aspirin hypersensitivity. Finally, perspectives on application of new genomic technologies are introduced; these will aid our understanding of the genetic pathogenesis of aspirin hypersensitivity in asthma.

Association between ADAM33 S2 and ST+4 polymorphisms and susceptibility to asthma: a meta-analysis

OBJECTIVE

The aim of this study was to determine whether ADAM33 (a disintegrin and metalloproteinase domain 33) polymorphisms confer susceptibility to asthma in different populations.

METHODS

We performed a meta-analysis on the association between the ADAM33 S2, ST+4, F+1, S1, and V4 polymorphisms and asthma.

RESULTS

Thirteen studies in ten reports, which included 4942 patients and 7933 controls, were available for the meta-analysis. Meta-analysis stratified by ethnicity indicated an association between the ADAM33 S2 2 allele and asthma in Europeans (OR=0.912, 95% CI=0.851-0.977, p=0.009). Meta-analysis revealed an association between asthma and the ADAM33 ST+4 2 allele (OR=0.783, 95% CI=0.762-0.999, p=0.048). Stratification by ethnicity indicated an association between the ADAM33 ST+4 polymorphism and asthma in Asians. Stratification by age indicated an association between the ADAM33 ST+4 2 allele and asthma in adults (OR=0.863, 95% CI=0.782-0.964, p=0.008). However, no association was found between asthma and the ADAM33 F+1, S1, and V4 polymorphisms.

CONCLUSIONS

This meta-analysis demonstrates that the ADAM33 S2 polymorphism confers susceptibility to asthma in Europeans and the ADAM33 ST+4 polymorphism is associated with asthma in Asians and adults.

Association of ADAM33 gene polymorphisms with asthma in the Uygur population of China

Asthma is one of the most common chronic respiratory diseases, affecting ∼300 million children and adults worldwide. Previous studies identified a disintegrin and metalloprotease domain 33 (ADAM33) as an important susceptibility gene for asthma in patients of different nationalities; however, it is unknown whether this relationship exists in ethnically diverse populations. The present study focused on the association between single-nucleotide polymorphisms (SNPs) of the ADAM33 gene and asthma in the Uygur population of China. Three SNPs of ADAM33 (T1, S+1 and F+1) were genotyped in a case-control study among the Chinese Uygur population, involving 126 adult asthmatic patients and 126 healthy controls. The frequency of the ADAM33 T1 C allele among asthma patients was significantly higher compared to healthy controls (20.6 vs. 11.1%, P=0.003). The distribution of ADAM33 genotypes differed significantly between the two groups. The frequency of the T1 TC genotype was higher among patients compared to healthy controls [odds ratio (OR)=2.118, P=0.016] and the variant genotype, TC+CC, increased the risk of asthma (OR=2.244, P=0.005). Following adjustment for confounding factors, the ORs of TC and TC+CC for asthma were 2.317 and 2.522, respectively. There was a significant decrease in the forced expiratory volume (FEV₁) levels in patients with the TC genotype compared to the TT genotype of T1. Haplotype analysis revealed that the frequencies of Hap5 (CAC) and Hap6 (CAT) were significantly higher among asthmatic patients compared to healthy controls (P=0.024 and 0.016, respectively). The genotype and allele frequencies of SNP S+1 and F+1 were not statistically different between asthmatic patients and controls. In conclusion, the ADAM33 T1 SNP may affect susceptibility to asthma in the Chinese Uygur population.

A disintegrin and metalloprotease 33 (ADAM33) gene polymorphisms and the risk of asthma: a meta-analysis

Polymorphisms in the ADAM33 gene have been associated with asthma, but the data are controversial. Therefore, we reviewed the related studies and quantitatively summarized the associations between ADAM33 polymorphisms and asthma risk using meta-analysis. A dominant model (AA+Aa vs. aa), recessive model (AA vs. Aa+aa), additive model (AA vs. aa) and allelic model (A vs. a) were used to estimate the association between ADAM33 polymorphism and asthma risk. A total of 29 case-control studies referring to 14 SNPs were identified: rs2280091(T1), rs2787094(V4), rs528557(S2), rs2280090(T2), rs511898(F+1), rs44707(ST+4), rs3918396(S1), rs543749(V-1), rs574174(ST+7), rs597980(ST+5), rs2853209(S+1), rs2280089(T+1), rs612709(Q-1), and rs3746631(V5). The results indicated that S1, V-1, V5, S+1, S2, ST+4, ST+7, ST+5, and Q-1 were not associated with asthma. Significant associations were found with the T1, V4, F+1 and T+1 polymorphisms in the overall population. In the subgroup analysis by ethnicity, a positive result was only found for the T1, V4, F+1 and T2 polymorphisms in Asia but not in Europe or Latin America. This meta-analysis provides evidence that the T1, V4, F+1, T2, and T+1 polymorphisms in the ADAM33 gene are risk factors for asthma, especially in the Asian population.

The challenge of asthma in minority populations

The burden and disparity of asthma in race/ethnic minorities present a significant challenge. In this review, we will evaluate data on asthma epidemiology in minorities, examine potential reasons for asthma disparities, and discuss strategies of intervention and culturally sensitive care.

Association between ADAM33 T1 polymorphism and susceptibility to asthma in Asians

OBJECTIVE

The aim of this study was to determine whether the ADAM33 (a disintegrin and metalloproteinase domain 33) T1 (rs2280091), T2 (rs2280090), and ST+7 (rs574174) polymorphisms confer susceptibility to asthma.

METHODS

A meta-analysis stratified by ethnicity and age was conducted on associations between the ADAM33 T1, T2, and ST+7 polymorphisms and asthma.

RESULTS

Eleven studies, which included 4,124 patients and 7,094 controls, were available for the meta-analysis. Meta-analysis revealed an association between asthma and the ADAM33 T1 GG genotype [odds ratio (OR) = 2.257, 95 % confidence interval (CI) = 1.577-3.228, p = 8.42 × 10(-7)]. Stratification by ethnicity indicated an association between this genotype and asthma in Asians (OR = 2.683, 95 % CI = 1.799-4.001, p = 1.31 × 10(-7)), and stratification by age indicated an association between it and asthma in adults (OR = 1.895, 95 % CI = 1.005-3.573, p = 0.048). However, no association was found between asthma and the ADAM33 T2 and ST+7 polymorphisms.

CONCLUSIONS

This meta-analysis demonstrates that the ADAM33 T1 polymorphism confers susceptibility to asthma in Asians, but no association was found between the ADAM33 T2 and ST+7 polymorphisms and asthma susceptibility.

Association of ADAM33 gene polymorphisms with adult-onset asthma and its severity in an Indian adult population

ADAM33, a member of the ADAM (a disintegrin and metalloprotease) gene family, is an asthma susceptibility gene originally identified by positional cloning. In the present study, we investigated the possible association of five single-nucleotide polymorphisms (SNPs) in the ADAM33 (rs511898, rs528557, rs44707, rs597980 and rs2787094) with adult-onset asthma in an Indian population. The study included 175 patients with mild intermittent (n = 44), mild persistent (n = 108) or moderate persistent (n = 23) subgroups of asthma, and 253 nonasthmatic control individuals. SNPs were genotyped with the help of restriction fragment length polymorphism polymerase chain reaction (RFLP-PCR) method, and data were analysed using chi-square test and logistic regression model. Bonferroni's correction for multiple comparisons was applied for each hypothesis. Genotypes and allele frequencies of SNPs rs511898 and rs528557 were significantly associated with adult-onset asthma (P = 0.010-<0.001). A significant association of the homozygous mutant genotype and mutant alleles of SNPs rs2787094, rs44707 and rs597980 with the asthma was also observed (P = 0.020-<0.001). A positive association between asthma and haplotypes AGCCT, GGCCT, AGACT, GCAGT, GGACT, ACCCC and AGACC were also found (P = 0.036-<0.001, OR = 2.07-8.49). Haplotypes AGCGT, GCAGC, ACAGC, ACAGT, GGAGC and GGCGT appear to protect against asthma (P = 0.013-<0.0001, OR = 0.34-0.10). Our data suggest that ADAM33 gene polymorphisms serve as genetic risk factors for asthma in Indian adult population.

ADAM33 gene polymorphisms associate with asthma susceptibility and severity in East China han population

OBJECTIVE

Multiple genetic and environmental factors impact the pathogenesis of asthma. ADAM33 (a disintegrin and metalloproteinase domain 33) represents a novel susceptibility gene for asthma in several diverse populations. The aim of this study was to determine whether single nucleotide polymorphisms (SNPs) of the ADAM33 gene associate with asthma susceptibility and severity in the Chinese Han population.

METHODS

A total of 224 subjects were enrolled, including 74 normal controls and 150 asthmatic patients. The asthmatic enrollees were further categorized into high- or low-severity groups according to the percentage of forced expiratory volume in 1 second of predicted value, symptoms, nighttime awakening, requirement for short-acting β2-agonist, and interference with normal activities. Six SNPs (F + 1, ST + 4, S1, S2, T1, and T2) in ADAM33 were genotyped using the polymerase chain restriction fragment length polymorphism method.

RESULTS

Three SNPs (F + 1, T1, and T2) of ADAM33 were found to have significant associations with asthma in the study population (p = .0058-.0067). The allele frequencies of two SNPs (F + 1, T1) in both the low- and high-severity groups were significantly different from the allele frequency in the control group. The allelic frequency of the T2 SNP was significantly different from that of the control group only in the high-severity group (p = .0081). Haplotype analysis demonstrated that the frequency of 7575G, 12433T, and 12462C (GTC haplotype) is higher in healthy controls than amongst asthma patients (78.4% vs. 61.8%, p = .0004).

CONCLUSIONS

Polymorphisms of the ADAM33 gene associate with asthma susceptibility in the east China Han population, and the genetic association is stronger in high-severity asthmatics.

Association of ADAM33 polymorphisms with childhood asthma in a northern Chinese population

BACKGROUND

Genetic factors contribute to the increasing incidence of childhood asthma. The ADAM33 (a disintegrin and metalloprotease domain-containing protein 33) gene, discovered through positional cloning, is the first to be associated with asthma and bronchial hyperresponsiveness. This case-control study conducted in a Han Chinese population in northern China compared the genotypes of child asthmatic patients to healthy controls for the presence of 6 single nucleotide polymorphisms (SNPs) in the ADAM33 gene.

METHODS

The study population was composed of 412 children with asthma and 397 healthy controls. We genotyped 6 SNPs (F+1, T+1, T2, T1, V4, and Q-1) of ADAM33 with the PCR-restriction fragment length polymorphism (PCR-RFLP) method. Data were statistically analyzed to determine if an association existed between these genotypes and childhood asthma morbidity.

RESULTS

Three SNPs (T+1, T1, and V4) and 4 haplotypes (H1, H3, H5, and H8) were strongly associated with childhood asthma in children of northern China compared to healthy controls (P<0.05), whereas the other tested SNPs and haplotypes demonstrated no significant relationship.

CONCLUSION

The ADAM33 gene plays an important role in facilitating susceptibility to childhood asthma in this Han Chinese population.

Asthma phenotypes in adults and clinical implications

It is becoming increasingly recognized that asthma is a heterogeneous disease, whether based on clinical factors, including the patient's age at diagnosis, symptom spectrum and treatment response, triggering factors, or the level and type of inflammation. Attempts to analyze the importance of these characteristics to the clinical presentation of asthma have led to the appreciation of numerous separate and overlapping asthma phenotypes. However, these approaches are 'biased' and based on the clinician/scientist's own experience. Recently, unbiased approaches have also been attempted using both molecular and statistical tools. Early results from these approaches have supported and expanded on the clinician's concepts. However, until specific biologic markers are identified for any of these proposed phenotypes, the definitive nature of any phenotype will remain speculative.

Association of ADAM33 gene polymorphisms with asthma in a Chinese population

BACKGROUND AND AIM

Asthma is a very common disease involving genetic and environmental factors. A disintegrin and metalloproteinase 33 (ADAM33) has been one of the most exciting candidate genes for asthma since its first association with the disease in the white population. Recently, studies on the association of ADAM33 gene polymorphisms with the risk of asthma have been controversial. We therefore focused on testing the hypothesis that either single-nucleotide polymorphisms (SNPs) of the ADAM33 gene may be associated with asthma risk. The aim of this study was to evaluate the potential relationship between polymorphisms of ADAM33 and asthma in a Han population in China.

METHODS

A case control study was conducted in a Han population of eastern Chinese population. A total of 329 asthma patients and a control group of 316 healthy volunteers were recruited for this study. Four polymorphic sites (F+1, S2, T2 and V4) were selected for genotyping. Genotypes were determined by the allele-specific polymerase chain reaction with fluorescence melting curves and DNA sequencing method. Data were analysed using the chi-squared test software.

RESULTS

Statistically significant differences in the distributions of the S2 site between patients and controls were observed (χ2=7.140, P<0.05).

CONCLUSION

These preliminary results suggest an association between ADAM33 polymorphisms S2 C/G and asthma in a Chinese Han population. The SNPs (F+1 C/T, T2 G/A and V4 C/G) of the ADAM33 gene may be the causal variants in asthma disease, but the strength of this evidence is limited by our small sample size.

The search for genetic variants and epigenetics related to asthma

For the past two decades, a huge number of genetic studies have been conducted to identify the genetic variants responsible for asthma risk. Several types of genetic and genomic approaches, including linkage analysis, candidate gene single nucleotide polymorphism studies, and whole genome-wide association studies have been applied. In this review article, the results of these approaches are summarized, and their limitations are discussed. Additionally, perspectives for applying upcoming new epigenetic or genomic technologies, such as copy number variation, are introduced to increase our understanding of new omic approaches to asthma genetics.

Evaluation of genetic susceptibility to childhood allergy and asthma in an African American urban population

BACKGROUND

Asthma and allergy represent complex phenotypes, which disproportionately burden ethnic minorities in the United States. Strong evidence for genomic factors predisposing subjects to asthma/allergy is available. However, methods to utilize this information to identify high risk groups are variable and replication of genetic associations in African Americans is warranted.

METHODS

We evaluated 41 single nucleotide polymorphisms (SNP) and a deletion corresponding to 11 genes demonstrating association with asthma in the literature, for association with asthma, atopy, testing positive for food allergens, eosinophilia, and total serum IgE among 141 African American children living in Detroit, Michigan. Independent SNP and haplotype associations were investigated for association with each trait, and subsequently assessed in concert using a genetic risk score (GRS).

RESULTS

Statistically significant associations with asthma were observed for SNPs in GSTM1, MS4A2, and GSTP1 genes, after correction for multiple testing. Chromosome 11 haplotype CTACGAGGCC (corresponding to MS4A2 rs574700, rs1441586, rs556917, rs502581, rs502419 and GSTP1 rs6591256, rs17593068, rs1695, rs1871042, rs947895) was associated with a nearly five-fold increase in the odds of asthma (Odds Ratio (OR) = 4.8, p = 0.007). The GRS was significantly associated with a higher odds of asthma (OR = 1.61, 95% Confidence Interval = 1.21, 2.13; p = 0.001).

CONCLUSIONS

Variation in genes associated with asthma in predominantly non-African ethnic groups contributed to increased odds of asthma in this African American study population. Evaluating all significant variants in concert helped to identify the highest risk subset of this group.

Association of ADAM33 gene polymorphisms with asthma in Indian children

Asthma is the most common chronic disorder in childhood, and asthma exacerbation is an important cause of childhood morbidity and hospitalization. In the present study, the relationship between single-nucleotide polymorphisms (SNPs) of the ADAM33 gene and asthma in Indian children has been examined using a case-control study. Five SNPs of the ADAM33 gene, F+1(rs511898) G/A, S2 (rs528557) G/C, ST+4 (rs44707) A/C, ST+5 (rs597980) C/T and V4 (rs2787094) C/G, were analyzed in 211 asthma cases and 137 controls aged 1-15 years using the PCR-restriction fragment length polymorphism method. Data were statistically analyzed using the χ(2)-test and logistic regression model. Haplotype estimation and linkage disequilibrium were conducted using the expectation-maximization algorithm. The genotypes and allele frequencies of SNPs S2 and ST+5 of the ADAM33 gene were significantly associated with asthma risk (P = 0.020 - < 0.001), whereas F+1, ST+4, V4 homozygous mutant genotypes and mutant alleles were significantly associated with increased asthma risk (P = 0.031 - < 0.001). A positive association was also found with haplotypes AGCCT, GGACT and AGCCC (P = < 0.001, odds ratio (OR) = 6.10-6.50), whereas ACAGT, AGCGC, AGCGT, GCAGC and GCCGT showed protective association with asthma (P = 0.019-0.000, OR = 0.50-0.20). Taken together, out results suggest that ADAM33 gene polymorphisms may modify individual susceptibility to develop childhood asthma in the Indian population.

Association of ADAM33 gene with susceptibility to COPD in Tibetan population of China

Chronic obstructive pulmonary disease (COPD) is a common, complex disorder associated with substantial morbidity and mortality, influenced by both environmental factor and genetic factor. ADAM33 gene was found to be associated with asthma, declined lung function and COPD. The purpose of the study was to test whether SNPs in ADAM33 were associated with COPD in Tibetan population of China. Polymerase chain reaction-restriction fragment length polymorphism was carried out to genotype the eight SNPs (V4, T2, T1, S2, S1, Q-1 and F + 1) of ADAM33 on 240 COPD patients and 221 healthy individuals. Four SNPs (V4, T2, T1 and S1) and four haplotypes (H2 CGAAGAGC, H5 GAGAGAGC, H9 GAAAGAGC and H6 CGGGGAGC of ADAM33 gene were associated with COPD significantly (defined as P < 0.05). The results indicate that there is an association between ADAM33 polymorphisms and COPD in Tibetan population of China.

Past, present, and future of allergy in Korea

Korean allergology has made great progress in keeping pace with global scientific advances in spite of a short history. Outstanding academic and scientific researches have been performed in a variety of allergy fields in Korea. Epidemiologic studies revealed increasing prevalence of asthma and allergic diseases and considerable morbidity and mortality in Korea. Novel inhalant allergens such as citrus red mite and two-spotted spider mite as causes of asthma and allergic rhinitis have been discovered and reported in Korea. Bidirectional translational researches have been performed and are underway to elucidate the pathogenesis of asthma and allergy, mechanisms of airway inflammation and remodeling, and new therapeutic modalities for asthma and allergic diseases. Experimental asthma models of different phenotypes according to exposed levels of lipopolysaccharide or double-stranded RNA suggested the crucial role of the innate immunity in the development of allergic airway inflammation and a new insight for asthma pathogenesis, in which both Th1 and Th2 inflammation are involved. In the field of genetic researches, numerous genetic associations with asthma and asthma-related phenotypes, such as atopy, IgE production, and airway hyperresponsiveness, have been demonstrated in Korean population. The Easy Asthma Management (EAM) program, a computer-assisted asthma management program, is anticipated to facilitate the achievement of more successful clinical outcomes by filling the gaps between guidelines and actual practices. The Integration of these multi-disciplinary allergy research resources and translation of scientific achievements to the bedside and society will lead to better allergy and asthma control in Korea.

Association of IL-4 and ADAM33 gene polymorphisms with asthma in an Indian population

There are more than 100 candidate genes of asthma located on 23 human chromosomes. Interleukin-4 (IL-4), located on chromosome 5q31, and ADAM33, located on chromosome 20p13, and some single nucleotide polymorphisms (SNPs) of these genes have been shown to be associated with asthma and its manifestations in different populations. The most prominent SNPs of IL-4 and ADAM33 are 589C>T and 400A>G, respectively. There are also controversial reports on the association of these SNPs with asthma. In the present study, we analyzed these two SNPs in 100 patients with asthma and 50 controls through PCR amplification and restriction digestion to evaluate association of these two SNPs with asthma. The nonsignificant differences were observed for the IL-4 promoter polymorphism C589T and the ADAM33 T1 polymorphism between asthmatic patients and controls (P = 0.638 and 0.943, respectively). Our data revealed that there is no association of these SNPs with asthma indicating that other SNPs of these genes or other genes might be involved in the manifestation of asthma.

Positive association between aspirin-intolerant asthma and genetic polymorphisms of FSIP1: a case-case study

BACKGROUND

Aspirin-intolerant asthma (AIA), which is caused by non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin, causes lung inflammation and reversal bronchi reduction, leading to difficulty in breathing. Aspirin is known to affect various parts inside human body, ranging from lung to spermatogenesis. FSIP1, also known as HDS10, is a recently discovered gene that encodes fibrous sheath interacting protein 1, and is regulated by amyloid beta precursor protein (APP). Recently, it has been reported that a peptide derived from APP is cleaved by alpha disintegrin and metalloproteinase 33 (ADAM33), which is an asthma susceptibility gene. It has also been known that the FSIP1 gene is expressed in airway epithelium.

OBJECTIVES

Aim of this study is to find out whether FSIP1 polymorphisms affect the onset of AIA in Korean population, since it is known that AIA is genetically affected by various genes.

METHODS

We conducted association study between 66 single nucleotide polymorphisms (SNPs) of the FSIP1 gene and AIA in total of 592 Korean subjects including 163 AIA and 429 aspirin-tolerant asthma (ATA) patients. Associations between polymorphisms of FSIP1 and AIA were analyzed with sex, smoking status, atopy, and body mass index (BMI) as covariates.

RESULTS

Initially, 18 SNPs and 4 haplotypes showed associations with AIA. However, after correcting the data for multiple testing, only one SNP showed an association with AIA (corrected P-value = 0.03, OR = 1.63, 95% CI = 1.23-2.16), showing increased susceptibility to AIA compared with that of ATA cases. Our findings suggest that FSIP1 gene might be a susceptibility gene for aspirin intolerance in asthmatics.

CONCLUSION

Although our findings did not suggest that SNPs of FSIP1 had an effect on the reversibility of lung function abnormalities in AIA patients, they did show significant evidence of association between the variants in FSIP1 and AIA occurrence among asthmatics in a Korean population.

The role of the epithelium in airway remodeling in asthma

The bronchial epithelium is the barrier to the external environment and plays a vital role in protection of the internal milieu of the lung. It functions within the epithelial-mesenchymal trophic unit to control the local microenvironment and help maintain tissue homeostasis. However, in asthma, chronic perturbation of these homeostatic mechanisms leads to alterations in the structure of the airways, termed remodeling. Damage to the epithelium is now recognized to play a key role in driving airway remodeling. We have postulated that epithelial susceptibility to environmental stress and injury together with impaired repair responses results in generation of signals that act on the underlying mesenchyme to propagate and amplify inflammatory and remodeling responses in the submucosa. Many types of challenges to the epithelium, including pathogens, allergens, environmental pollutants, cigarette smoke, and even mechanical forces, can elicit production of mediators by the epithelium, which can be translated into remodeling responses by the mesenchyme. Several important mediators of remodeling have been identified, most notably transforming growth factor-beta, which is released from damaged/repairing epithelium or in response to inflammatory mediators, such as IL-13. The cross talk between the epithelium and the underlying mesenchyme to drive remodeling responses is considered in the context of subepithelial fibrosis and potential pathogenetic mechanisms linked to the asthma susceptibility gene, a disintegrin and metalloprotease (ADAM)33.

Role of ADAM and ADAMTS metalloproteinases in airway diseases

Lungs are exposed to the outside environment and therefore to toxic and infectious agents or allergens. This may lead to permanent activation of innate immune response elements. A Disintegrin And Metalloproteinases (ADAMs) and ADAMs with Thrombospondin motifs (ADAMTS) are proteinases closely related to Matrix Metalloproteinases (MMPs). These multifaceted molecules bear metalloproteinase and disintegrin domains endowing them with features of both proteinases and adhesion molecules. Proteinases of the ADAM family are associated to various physiological and pathological processes and display a wide spectrum of biological effects encompassing cell fusion, cell adhesion, "shedding process", cleavage of various substrates from the extracellular matrix, growth factors or cytokines... This review will focus on the putative roles of ADAM/ADAMTS proteinases in airway diseases such as asthma and COPD.

A Six-SNP haplotype of ADAM33 is associated with asthma in a population of Cartagena, Colombia

BACKGROUND

A disintegrin and metalloprotein-33 (ADAM33) participates in the bronchial remodeling process in asthma, and genetic analyses pointed it out as a candidate gene in asthma.

METHODS

To analyze the association between ADAM33 and asthma and total and mite-specific IgE levels in a population of the Caribbean Coast of Colombia, we genotyped 6 single-nucleotide polymorphisms of ADAM33 in 429 asthmatics, 401 controls and 116 family trios using fluorogenic probes. Total and specific IgE against Blomia tropicalis and Dermatophagoides pteronyssinus were determined by ELISA. Case-control and family-based analyses were performed. Case-control association analyses were corrected by population stratification using a set of 52 ancestry-informative markers.

RESULTS

Eight common haplotypes were identified; among them, H4 (GCAGGG) was associated with asthma in the family group (Z score: -2.049, p = 0.04). We also found an association between the TT genotype of ST+7 and asthma in the case-control study (p = 0.05) that disappeared after correcting for multiple testing. In the family-based analysis, this genotype was a risk factor for asthma (p = 0.01), high total IgE (Z score: 2.546, p = 0.01) and high specific IgE against B. tropicalis (p = 0.02) and D. pteronyssinus (Z score: 2.414, p = 0.01). V4 was associated with specific IgE against B. tropicalis (p = 0.03); T2 with asthma (p = 0.03), high total IgE (p = 0.02) and IgE against D. pteronyssinus (p = 0.03) and T1 with high total IgE (p = 0.04). None of these associations was maintained after correction for multiple testing.

CONCLUSIONS

Our findings suggest a relevant role of ADAM33 in thepathogenesis of asthma in this population.

The effects of Th2 cytokines on the expression of ADAM33 in allergen-induced chronic airway inflammation

A disintegrin and metalloprotease domain 33 (ADAM33) has been identified as an asthma susceptibility gene, which is associated with small-airway remodeling. However, the role of ADAM33 in the development of allergic airway inflammation is unclear. The present study used an established murine model of allergen-induced chronic airway inflammation, which was sensitized and then challenged by nebulized 2.5% ovalbumin (OVA) for 8 weeks (30 min/day, three times a week). The expression of ADAM33 mRNA detected by real time RT-PCR was significantly enhanced in the lung tissue of mice with OVA challenge, as compared with the group challenged with saline. This OVA-challenged model showed significant Th2-biased airway inflammation as well as airway remodeling with features of sub-epithelial fibrosis and mucus hyper-secretion. Furthermore, in vitro studies showed that IL-4 and IL-13 could significantly up-regulate the expression of ADAM33 mRNA in human fibroblasts in a concentration- and time-dependent manner as compared to normal controls. These results support the note that Th2 cytokines can up-regulate the expression of ADAM33 mRNA and ADAM33 may play an important role in the development of airway remodeling in allergen-induced chronic airway inflammation.

ADAM8: a new therapeutic target for asthma

BACKGROUND

A proteinase with a disintegrin and a metalloproteinase domain-8 (ADAM8) has been linked to asthma.

OBJECTIVE

To explore whether ADAM8 is a therapeutic target for asthma.

METHODS

We reviewed literature on ADAM8's function and expression and activities in lungs of humans and mice with allergic airway inflammation (AAI). We used these data to generate hypotheses about the contributions of ADAM8 to asthma pathogenesis.

CONCLUSIONS

ADAM8 levels are increased in airway epithelium and airway inflammatory cells in mice with AAI and human asthma patients. Data from murine models of AAI indicate that ADAM8 dampens airway inflammation. It is not clear whether ADAM8 contributes directly to structural remodeling in asthmatic airways. Additional studies are required to validate ADAM8 as a therapeutic target for asthma.

Asthma and ethnic minorities: socioeconomic status and beyond

PURPOSE OF REVIEW

We aim to discuss current insights into our understanding of the mechanisms by which socioeconomic status influences the prevalence and severity of asthma in ethnic minorities. In addition, we review potential risk factors for ethnic disparities in asthma that are not mediated by socioeconomic status.

RECENT FINDINGS

Exposures and factors correlated with ethnicity through socioeconomic status (e.g. indoor and outdoor air quality, smoke exposure, and access to healthcare) are likely to explain a significant proportion of the observed ethnic differences in asthma morbidity. However, other factors correlated with ethnicity (e.g. genetic variation) can impact ethnic disparities in asthma independently of and/or interacting with socioeconomic status-related factors.

SUMMARY

Socioeconomic status is a rough marker of a variety of environmental/behavioral exposures and a very important determinant of differences in asthma prevalence and severity among ethnic minorities in the United States. However, socioeconomic status is unlikely to be the sole explanation for ethnic disparities in asthma, which may also be due to differences in genetic variation and gene-by-environment interactions among ethnic groups.

Adam33 polymorphisms are associated with COPD and lung function in long-term tobacco smokers

Background

Variation in ADAM33 has been shown to be important in the development of asthma and altered lung function. This relationship however, has not been investigated in the population susceptible to COPD; long term tobacco smokers. We evaluated the association between polymorphisms in ADAM33 gene with COPD and lung function in long term tobacco smokers.

Methods

Caucasian subjects, at least 50 year old, who smoked ≥ 20 pack-years (n = 880) were genotyped for 25 single nucleotide polymorphisms (SNPs) in ADAM33. COPD was defined as an FEV1/FVC ratio < 70% and percent-predicted (pp)FEV1 < 75% (n = 287). The control group had an FEV1/FVC ratio ≥ 70% and ppFEV₁ ≥ 80% (n = 311) despite ≥ 20 pack years of smoking. Logistic and linear regressions were used for the analysis. Age, sex, and smoking status were considered as potential confounders.

Results

Five SNPs in ADAM33 were associated with COPD (Q-1, intronic: p < 0.003; S1, Ile → Val: p < 0.003; S2, Gly → Gly: p < 0.04; V-1 intronic: p < 0.002; V4, in 3' untranslated region: p < 0.007). Q-1, S1 and V-1 were also associated with ppFEV1, FEV1/FVC ratio and ppFEF25–75 (p values 0.001 – 0.02). S2 was associated with FEV1/FVC ratio (p < 0.05). The association between S1 and residual volume revealed a trend toward significance (p value < 0.07). Linkage disequilibrium and haplotype analyses suggested that S1 had the strongest degree of association with COPD and pulmonary function abnormalities.

Conclusion

Five SNPs in ADAM33 were associated with COPD and lung function in long-term smokers. Functional studies will be needed to evaluate the biologic significance of these polymorphisms in the pathogenesis of COPD.