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1.  The role of polymorphisms in ADAM33, a disintegrin and metalloprotease 33, in childhood asthma and lung function in two German populations 
Respiratory Research  2006;7(1):91.
ADAM33, the first asthma candidate gene identified by positional cloning, may be associated with childhood asthma, lung function decline and bronchial hyperresponsiveness. However, replication results have been inconclusive in smaller previous study populations probably due to inconsistencies in asthma phenotypes or yet unknown environmental influences. Thus, we tried to further elucidate the role of ADAM33 polymorphisms (SNPs) in a genetic analysis of German case control and longitudinal populations.
Using MALDI-TOF, ten ADAM33 SNPs were genotyped in 1,872 children from the International Study of Asthma and Allergy in Childhood (ISAAC II) in a case control setting and further 824 children from the longitudinal cohort Multicentre Study of Allergy (MAS). In both populations the effects of single SNPs and haplotypes were studied and a gene environment analysis with passive smoke exposure was performed using SAS/Genetics.
No single SNP showed a significant association with doctor's diagnosis of asthma. A trend for somewhat more profound effects of ADAM33 SNPs was observed in individuals with asthma and BHR. Haplotype analyses suggested a minor effect of the ADAM33 haplotype H4 on asthma (p = 0.033) but not on BHR. Associations with non atopic asthma and baseline lung function were identified but no interaction with passive smoke exposure could be detected.
The originally reported association between ADAM33 polymorphisms and asthma and BHR could not be confirmed. However, our data may suggest a complex role of ADAM33 polymorphisms in asthma ethiology, especially in non atopic asthma.
PMCID: PMC1550399  PMID: 16784537
2.  Regulation of A Disintegrin And Metalloprotease-33 Expression by Transforming Growth Factor-β 
The asthma susceptibility gene, a disintegrin and metalloprotease-33 (ADAM33), is selectively expressed in mesenchymal cells, and the activity of soluble ADAM33 has been linked to angiogenesis and airway remodeling. Transforming growth factor (TGF)-β is a profibrogenic growth factor, the expression of which is increased in asthma, and recent studies show that it enhances shedding of soluble ADAM33. In this study, we hypothesized that TGF-β also affects ADAM33 expression in bronchial fibroblasts in asthma. Primary fibroblasts were grown from bronchial biopsies from donors with and those without asthma, and treated with TGF-β2 to induce myofibroblast differentiation. ADAM33 expression was assessed using quantitative RT-PCR and Western blotting. To examine the mechanisms whereby TGF-β2 affected ADAM33 expression, quantitative methylation-sensitive PCR, chromatin immunoprecipitation, and nuclear accessibility assays were conducted on the ADAM33 promoter. We found that TGF-β2 caused a time- and concentration-dependent reduction in ADAM33 mRNA expression in normal and asthmatic fibroblasts, affecting levels of splice variants similarly. TGF-β2 also induced ADAM33 protein turnover and appearance of a cell-associated C-terminal fragment. TGF-β2 down-regulated ADAM33 mRNA expression by causing chromatin condensation around the ADAM33 promoter with deacetylation of histone H3, demethylation of H3 on lysine-4, and hypermethylation of H3 on lysine-9. However, the methylation status of the ADAM33 promoter did not change. Together, these data suggest that TGF-β2 suppresses expression of ADAM33 mRNA in normal or asthmatic fibroblasts. This occurs by altering chromatin structure, rather than by gene silencing through DNA methylation as in epithelial cells. This may provide a mechanism for fine regulation of levels of ADAM33 expression in fibroblasts, and may self-limit TGF-β2–induced ectodomain shedding of ADAM33.
PMCID: PMC3359905  PMID: 22227561
a disintegrin and metalloprotease-33; myofibroblast; transforming growth factor-β; histone modification
3.  Association of a disintegrin and metalloprotease 33 gene polymorphisms with asthma 
Molecular and Clinical Oncology  2014;2(6):1076-1080.
Various studies reported a disintegrin and metalloprotease 33 (ADAM33) as an important susceptibility gene for asthma, which is frequently detected among certain populations. The aim of the present study was to investigate the association between single-nucleotide polymorphisms (SNPs) of the ADAM33 gene and asthma. Our case-control study included 183 patients (73 male and 110 female, mean age 42.93±13.48 years) who were admitted in the First Affiliated Hospital of Xinjiang Medical University between February, 2012 and May, 2013 and 155 healthy controls (66 male and 89 female, mean age 41.14±14.10 years). Allele-specific polymerase chain reaction technology and DNA testing training methods were applied to detect the T2 and ST+5 polymorphisms of the ADAM33 gene. The data were statistically analyzed to determine whether there exists an association between these genotypes and asthma-related morbidity. The genotypes and allele frequencies of the T2 and ST+5 SNPs of ADAM33 were not found to be significantly associated with asthma risk when compared between asthmatic patients and healthy controls (P>0.05). In addition, there was no association of the investigated SNPs with the severity of asthma. There was no significant difference in the forced vital capacity and the forced expiratory volume between patients with the ADAM33 T2 and ST+5 genotype. In conclusion, our results suggested that the T2 and ST+5 ADAM33 gene polymorphisms do not confer a significant risk of asthma or affect its severity in the population investigated.
PMCID: PMC4179825  PMID: 25279200
a disintegrin and metalloprotease 33 gene; single-nucleotide polymorphism; Uyghur; asthma
4.  Association of ADAM33 gene polymorphisms with asthma in the Uygur population of China 
Biomedical Reports  2013;1(3):447-453.
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.
PMCID: PMC3917077  PMID: 24648966
a disintegrin and metalloprotease domain 33; single-nucleotide polymorphisms; asthma; Uygur population; haplotype
5.  ADAM Metallopeptidase Domain 33 (ADAM33): A Promising Target for Asthma 
Mediators of Inflammation  2014;2014:572025.
Over the last few years, a significant progress has been made in understanding the role of a disintegrin and metalloproteinase 33 (ADAM33) in asthma. The previous observations for the association with asthma have been replicated in over 33 different population samples worldwide. We and others have performed association analysis and meta-analysis and provided further evidence that several polymorphisms in the ADAM33 are risk factors for asthma, especially in the Asian population. Further, several studies have suggested that alterations in epigenetic marks alter the patterns of DNA methylation of ADAM33 and result in potentially adverse biological effects. Finally, while the biological activities of ADAM33 are as yet unknown, ADAM33 may play a possible role in airway remodeling because of its high expression in epithelium, myo/fibroblasts, and airway smooth muscle cells (ASMCs) and its role in promoting angiogenesis and stimulating cell proliferation and differentiation. Thus, ADAM33 represents a promising target for asthma. However, further investigations are clearly needed to discover functional ADAM33 gene polymorphisms and the role of genetic/epigenetic factors in conferring genetic susceptibility to environmental exposure induced asthma as well as biological function in asthma. This, in turn, will unlock the possibility of ADAM33 as a target for asthma therapy.
PMCID: PMC4003756  PMID: 24817794
6.  Associations of genetic variants in ADAM33 and TGF-β1 genes with childhood asthma risk 
Biomedical Reports  2014;2(4):533-538.
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.
PMCID: PMC4051479  PMID: 24944803
TGF-β1; ADAM33; single-nucleotide polymorphism; asthma; risk; Chinese children; haplotype
7.  A Six-SNP Haplotype of ADAM33 Is Associated with Asthma in a Population of Cartagena, Colombia 
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.
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.
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.
Our findings suggest a relevant role of ADAM33 in thepathogenesis of asthma in this population.
PMCID: PMC2956007  PMID: 19940503
A disintegrin and metalloprotein 33; ADAM33; Immunoglobulin E; Asthma; Allergy; Colombians
8.  Comprehensive Testing of Positionally Cloned Asthma Genes in Two Populations 
Rationale: Replication of gene-disease associations has become a requirement in complex trait genetics.
Objectives: In studies of childhood asthma from two different ethnic groups, we attempted to replicate associations with five potential asthma susceptibility genes previously identified by positional cloning.
Methods: We analyzed two family-based samples ascertained through an asthmatic proband: 497 European-American children from the Childhood Asthma Management Program and 439 Hispanic children from the Central Valley of Costa Rica. We genotyped 98 linkage disequilibrium–tagging single-nucleotide polymorphisms (SNPs) in five genes: ADAM33, DPP10, GPR154 (HUGO name: NPSR1), HLA-G, and the PHF11 locus (includes genes SETDB2 and RCBTB1). SNPs were tested for association with asthma and two intermediate phenotypes: airway hyperresponsiveness and total serum immunoglobulin E levels.
Measurements and Main Results: Despite differing ancestries, linkage disequilibrium patterns were similar in both cohorts. Of the five evaluated genes, SNP-level replication was found only for GPR154 (NPSR1). In this gene, three SNPs were associated with asthma in both cohorts, although the opposite alleles were associated in either study. Weak evidence for locus-level replication with asthma was found in the PHF11 locus, although there was no overlap in the associated SNP across the two cohorts. No consistent associations were observed for the three other genes.
Conclusions: These results provide some further support for the role of genetic variation in GPR154 (NPSR1) and PHF11 in asthma susceptibility and also highlight the challenges of replicating genetic associations in complex traits such as asthma, even for genes identified by linkage analysis.
PMCID: PMC2048676  PMID: 17702965
bronchial hyperreactivity; immunoglobulin E; linkage disequilibrium; NPSR1; single-nucleotide polymorphism
9.  Expression of ADAMs and Their Inhibitors in Sputum from Patients with Asthma 
Molecular Medicine  2006;12(7-8):171-179.
ADAMs (a disintegrin and metalloprotease) constitute a family of cell surface proteins containing disintegrin and metalloprotease domains which associate features of adhesion molecules and proteases. ADAMTSs (a disintegrin and metalloprotease with thrombospondin motifs) bear thrombospondin type I motifs in C-terminal extremity, and most of them are secreted proteins. Because genetic studies have shown that ADAM-33 gene polymorphisms are associated with asthma, we designed this study to assess mRNA expression profile of several ADAM and ADAMTS proteases in sputum from patients with asthma and to investigate the relationship between expression of these proteases and asthma-associated inflammation and airway obstruction. mRNA expression profile of selected ADAM and ADAMTS proteinases (ADAM-8, -9, -10, -12, -15, -17, and -33; ADAMTS-1, -2, -15, -16, -17, -18, and -19), their physiological inhibitors TIMP-1 and TIMP-3, and RECK, a membrane-anchored MMP activity regulator, was obtained by RT-PCR analysis performed on cells collected by sputum induction from 21 patients with mild to moderate asthma and 17 healthy individuals. mRNA levels of ADAM-8, ADAM-9, ADAM-12, TIMP-1, and TIMP-3 were significantly increased, whereas mRNA levels coding for ADAMTS-1, ADAMTS-15, and RECK were significantly decreased in patients with asthma compared with control patients. ADAM-8 expression was negatively correlated with the forced expiratory volume at the first second (FEV1) (r = −0.57, P < 0.01), whereas ADAMTS-1 and RECK expressions were positively correlated to FEV1 (r = 0.45, P < 0.05, and r = 0.55, P = 0.01, respectively). We conclude that expression of ADAMs and ADAMTSs and their inhibitors is modulated in airways from patients with asthma and that these molecules may play a role in the pathogenesis of asthma.
PMCID: PMC1626598  PMID: 17088949
10.  Genetic polymorphisms and asthma: findings from a case–control study in the Madeira island population 
Biological Research  2014;47(1):40.
Asthma is a complex disease influenced by multiple genetic and environmental factors. While Madeira has the highest prevalence of asthma in Portugal (14.6%), the effect of both genetic and environmental factors in this population has never been assessed. We categorized 98 asthma patients according to the Global Initiative for Asthma (GINA) guidelines, established their sensitization profile, and measured their forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) indexes. Selected single nucleotide polymorphisms (SNPs) were analysed as potential markers for asthma susceptibility and severity in the interleukin 4 (IL4), interleukin 13 (IL13), beta-2-adrenergic receptor (ADRB2), a disintegrin and metalloprotease 33 (ADAM33), gasdermin-like (GSDML) and the signal transducer and activator of transcription 6 (STAT6) genes comparatively to a population reference set.
Although mites are the major source of allergic sensitization, no significant difference was found amongst asthma severity categories. IL4-590*CT/TT and IL4-RP2*253183/183183 were found to predict the risk (2-fold) and severity (3 to 4-fold) of asthma and were associated with a lower FEV1 index. ADRB2-c.16*AG is a risk factor (3.5-fold), while genotype GSDML-236*TT was protective (4-fold) for moderate-severe asthma. ADAM33-V4*C was associated to asthma and mild asthma by the transmission disequilibrium test (TDT). Finally, ADAM33-V4*CC and STAT6-21*TT were associated with higher sensitization (mean wheal size ≥10 mm) to house dust (1.4-fold) and storage mite (7.8-fold).
In Madeira, IL4-590C/T, IL4-RP2 253/183, GSDML-236C/T and ADAM33-V4C/G SNPs are important risk factors for asthma susceptibility and severity, with implications for asthma healthcare management.
Electronic supplementary material
The online version of this article (doi:10.1186/0717-6287-47-40) contains supplementary material, which is available to authorized users.
PMCID: PMC4167518  PMID: 25299150
Asthma; Madeira; SNPs; Susceptibility; Severity
11.  Assessing the Validity of Asthma Associations for Eight Candidate Genes and Age at Diagnosis Effects 
PLoS ONE  2013;8(9):e73157.
Before the advent of genome-wide association studies (GWAS), ADAM33, ADRB2, CD14, MS4A2 (alias FCER1B), IL13, IL4, IL4R, and TNF constituted the most replicated non-HLA candidate genes with asthma and related traits. However, except for the IL13-IL4 region, none of these genes have been found in close proximity of genome-wide significant hits among GWAS for asthma or related traits. Here we aimed to assess the reproducibility of these asthma associations and to test if associations were more evident considering the effect of age at diagnosis.
Methodology/Principal Findings
We systematically evaluated 286 common single nucleotide polymorphisms (SNPs) of these 8 genes in a sample of 1,865 unrelated Spanish individuals (606 asthmatics and 1,259 controls). We found that variants at MS4A2, IL4R and ADAM33 genes demonstrated varying association effects with the age at diagnosis of asthma, with 10 SNPs showing study-wise significance after the multiple comparison adjustment. In addition, in silico replication with GWAS data supported the association of IL4R.
Our results support the important role of MS4A2, IL4R and ADAM33 genes in asthma and/or atopy susceptibility. However, additional studies in larger samples sets are needed to firmly implicate these genes in asthma susceptibility, and also to identify the causal variation underlying the associations found.
PMCID: PMC3767824  PMID: 24039878
12.  Increased expression of ADAM33 protein in asthmatic patients as compared to non-asthmatic controls 
Background & objectives:
ADAM33 is a member of a family of genes that encode membrane-anchored proteins with a disintegrin and a metalloprotease domain, primarily expressed in lung fibroblasts and bronchial smooth muscle cells. ADAM33 has been identified as a risk factor for asthma and is known as a gene associated with airway remodelling. The present study was conducted with the aims to investigate the expression of ADAM33 protein in patients of asthma and non-asthmatic controls, and to assess if the expression of ADAM33 protein relates with severity of asthma.
A total of 35 subjects, including 27 patients with asthma and eight non-asthmatic controls were included using Global Initiative for Asthma guidelines 2005. Bronchial biopsy tissues were collected and paraffin sections were made to store all study samples. Immunohistochemistry was performed using standardized protocol.
An increase in expression of ADAM33 protein was observed in the epithelium, smooth muscle and mesenchymal cells of asthma cases when compared to controls but there was no relationship with severity of asthma.
Interpretation & conclusions:
A higher expression of ADAM33 protein was seen in asthma patients compared to controls. Large prospective studies need to be done with adequate study design to confirm these preliminary finding.
PMCID: PMC3705658  PMID: 23640557
ADAM33 protein expression; asthma; bronchial biopsy; immunohistochemistry; severity of asthma
13.  Adam33 polymorphisms are associated with COPD and lung function in long-term tobacco smokers 
Respiratory Research  2009;10(1):21.
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.
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.
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.
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.
PMCID: PMC2664793  PMID: 19284602
14.  Replication of Association between ADAM33 Polymorphisms and Psoriasis 
PLoS ONE  2008;3(6):e2448.
Polymorphisms in ADAM33, the first gene identified in asthma by positional cloning, have been recently associated with psoriasis. No replication study of this association has been published so far. Data available in the French EGEA study (Epidemiological study on Genetics and Environment of Asthma, bronchial hyperresponsivensess and Atopy) give the opportunity to attempt to replicate the association between ADAM33 and psoriasis in 2002 individuals. Psoriasis (n = 150) has been assessed by questionnaire administered by an interviewer and a sub-sample of subjects with early-onset psoriasis (n = 74) has been identified based on the age of the subjects at time of interview (<40 years). Nine SNPs in ADAM33 and 11 SNPs in PSORS1 were genotyped. Association analysis was conducted by using two methods, GEE regression-based method and a likelihood-based method (LAMP program). The rs512625 SNP in ADAM33 was found associated with psoriasis at p = 0.01, the usual threshold required for replication (OR [95% CI] for heterozygotes compared to the reference group of homozygotes for the most frequent allele = 0.61 [0.42;0.89]). The rs628977 SNP, which was not in linkage disequilibrium with rs512625, was significantly associated with early-onset psoriasis (p = 0.01, OR [95% CI] for homozygotes for the minor allele compared to the reference group = 2.52 [1.31;4.86]). Adjustment for age, sex, asthma and a PSORS1 SNP associated with psoriasis in the EGEA data did not change the significance of these associations. This suggests independent effects of ADAM33 and PSORS1 on psoriasis. This is the first study that replicates an association between genetic variants in ADAM33 and psoriasis. Interestingly, the 2 ADAM33 SNPs associated with psoriasis in the present analysis were part of the 3-SNPs haplotypes showing the strongest associations in the initial study. The identification of a pleiotropic effect of ADAM33 on asthma and psoriasis may contribute to the understanding of these common immune-mediated diseases.
PMCID: PMC2413006  PMID: 18560587
15.  Association of ADAM33 gene polymorphisms with adult allergic asthma and rhinitis in a Chinese Han population 
BMC Medical Genetics  2008;9:82.
Rhinitis and asthma are very common diseases involving genetic and environmental factors. Most patients with asthma also have rhinitis, which suggests the concept of 'one airway, one disease.' A disintegrin and metalloproteinase 33 (ADAM33) is the first asthma-susceptible gene to be discovered by positional cloning. To evaluate the potential influence of ADAM33 gene polymorphisms on allergic rhinitis (AR) and allergic asthma (AS), a case-control study was conducted on the Han population of northeast China.
Six polymorphic sites (V4, T+1, T2, T1, S1, and Q-1) were genotyped in 128 patients with AR, 181 patients with AS, and 151 healthy controls (CTR). Genotypes were determined by the polymerase chain restriction fragment length polymorphism (PCR-RFLP) method. Data were analyzed using the chi-square test with Haploview software.
The single nucleotide polymorphisms (SNPs), V4 G/C, T+1 A/G, and T1 G/A, of the ADAM33 gene may be the causal variants in AR, whereas ADAM33 V4 G/C, T2 A/G, T1 G/A, and Q-1A/G may participate in the susceptibility of AS.
These results suggest that polymorphisms of the ADAM33 gene may modify individual susceptibility to AR and AS in a Chinese Han population.
PMCID: PMC2553063  PMID: 18778489
16.  Conservation and divergence of ADAM family proteins in the Xenopus genome 
Members of the disintegrin metalloproteinase (ADAM) family play important roles in cellular and developmental processes through their functions as proteases and/or binding partners for other proteins. The amphibian Xenopus has long been used as a model for early vertebrate development, but genome-wide analyses for large gene families were not possible until the recent completion of the X. tropicalis genome sequence and the availability of large scale expression sequence tag (EST) databases. In this study we carried out a systematic analysis of the X. tropicalis genome and uncovered several interesting features of ADAM genes in this species.
Based on the X. tropicalis genome sequence and EST databases, we identified Xenopus orthologues of mammalian ADAMs and obtained full-length cDNA clones for these genes. The deduced protein sequences, synteny and exon-intron boundaries are conserved between most human and X. tropicalis orthologues. The alternative splicing patterns of certain Xenopus ADAM genes, such as adams 22 and 28, are similar to those of their mammalian orthologues. However, we were unable to identify an orthologue for ADAM7 or 8. The Xenopus orthologue of ADAM15, an active metalloproteinase in mammals, does not contain the conserved zinc-binding motif and is hence considered proteolytically inactive. We also found evidence for gain of ADAM genes in Xenopus as compared to other species. There is a homologue of ADAM10 in Xenopus that is missing in most mammals. Furthermore, a single scaffold of X. tropicalis genome contains four genes encoding ADAM28 homologues, suggesting genome duplication in this region.
Our genome-wide analysis of ADAM genes in X. tropicalis revealed both conservation and evolutionary divergence of these genes in this amphibian species. On the one hand, all ADAMs implicated in normal development and health in other species are conserved in X. tropicalis. On the other hand, some ADAM genes and ADAM protease activities are absent, while other novel ADAM proteins in this species are predicted by this study. The conservation and unique divergence of ADAM genes in Xenopus probably reflect the particular selective pressures these amphibian species faced during evolution.
PMCID: PMC3055250  PMID: 20630080
17.  Analyses of associations between three positionally cloned asthma candidate genes and asthma or asthma-related phenotypes in a Chinese population 
BMC Medical Genetics  2009;10:123.
Six asthma candidate genes, ADAM33, NPSR1, PHF11, DPP10, HLA-G, and CYFIP2, located at different chromosome regions have been positionally cloned following the reported linkage studies. For ADAM33, NPSR1, and CYFIP2, the associations with asthma or asthma-related phenotypes have been studied in East Asian populations such as Chinese and Japanese. However, for PHF11, DPP10, and HLA-G, none of the association studies have been conducted in Asian populations. Therefore, the aim of the present study is to test the associations between these three positionally cloned genes and asthma or asthma-related phenotypes in a Chinese population.
Two, five, and two single nucleotide polymorphisms (SNPs) in the identified top regions of PHF11, DPP10, and HLA-G, respectively, were genotyped in 1183 independent samples. The study samples were selected based on asthma affectation status and extreme values in at least one of the following three asthma-related phenotypes: total serum immunoglobulin E levels, bronchial responsiveness test, and skin prick test. Both single SNP and haplotype analyses were performed.
We found that DPP10 was significantly associated with bronchial hyperresponsiveness (BHR) and BHR asthma after the adjustment for multiple testing; while the associations of PHF11 with positive skin reactions to antigens and the associations of HLA-G with BHR asthma were only nominally significant.
Our study is the first one to provide additional evidence that supports the roles of DPP10 in influencing asthma or BHR in a Chinese population.
PMCID: PMC2799396  PMID: 19951440
18.  IL-13-induced proliferation of airway epithelial cells: mediation by intracellular growth factor mobilization and ADAM17 
Respiratory Research  2007;8(1):51.
The pleiotrophic cytokine interleukin (IL)-13 features prominently in allergic and inflammatory diseases. In allergic asthma, IL-13 is well established as an inducer of airway inflammation and tissue remodeling. We demonstrated previously that IL-13 induces release of transforming growth factor-α (TGFα) from human bronchial epithelial cells, with proliferation of these cells mediated by the autocrine/paracrine action of this growth factor. TGFα exists as an integral membrane protein and requires proteolytic processing to its mature form, with a disintegrin and metalloproteinase (ADAM)17 responsible for this processing in a variety of tissues.
In this study, normal human bronchial epithelial (NHBE) cells grown in air/liquid interface (ALI) culture were used to examine the mechanisms whereby IL-13 induces release of TGFα and cellular proliferation. Inhibitors and antisense RNA were used to examine the role of ADAM17 in these processes, while IL-13-induced changes in the intracellular expression of TGFα and ADAM17 were visualized by confocal microscopy.
IL-13 was found to induce proliferation of NHBE cells, and release of TGFα, in an ADAM17-dependent manner; however, this IL-13-induced proliferation did not appear to result solely from ADAM17 activation. Rather, IL-13 induced a change in the location of TGFα expression from intracellular to apical regions of the NHBE cells. The apical region was also found to be a site of significant ADAM17 expression, even prior to IL-13 stimulation.
Results from this study indicate that ADAM17 mediates IL-13-induced proliferation and TGFα shedding in NHBE cells. Furthermore, they provide the first example wherein a cytokine (IL-13) induces a change in the intracellular expression pattern of a growth factor, apparently inducing redistribution of intracellular stores of TGFα to the apical region of NHBE cells where expression of ADAM17 is prominent. Thus, IL-13-induced, ADAM17-mediated release of TGFα, and subsequent epithelial cell proliferation, could contribute to the epithelial hypertrophy, as well as other features, associated with airway remodeling in allergic asthma.
PMCID: PMC1976612  PMID: 17620132
19.  Genetic variants in ADAM33 are associated with airway inflammation and lung function in COPD 
BMC Pulmonary Medicine  2014;14(1):173.
Genetic factors play a role in the development and severity of chronic obstructive pulmonary disease (COPD). The pathogenesis of COPD is a multifactorial process including an inflammatory cell profile. Recent studies revealed that single nucleotide polymorphisms (SNPs) within ADAM33 increased the susceptibility to COPD through changing the airway inflammatory process and lung function.
In this paper, we investigated associations of four polymorphisms (T1, T2, S2 and Q-1) of ADAM33 as well as their haplotypes with pulmonary function and airway inflammatory process in an East Asian population of patients with COPD.
We found that T1, T2 and Q-1 were significantly associated with the changes of pulmonary function and components of cells in sputum of COPD, and T1 and Q-1 were significantly associated with cytokines and mediators of inflammation in airway of COPD in recessive models. 10 haplotypes were significantly associated with transfer factor of the lung for carbon monoxide in the disease state, 4 haplotypes were significantly associated with forced expiratory volume in one second, and other haplotypes were associated with airway inflammation.
We confirmed for the first time that ADAM33 was involved in the pathogenesis of COPD by affecting airway inflammation and immune response in an East Asian population. Our results made the genetic background of COPD, a common and disabling disease, more apparent, which would supply genetic support for the study of the mechanism, classification and treatment for this disease.
Electronic supplementary material
The online version of this article (doi:10.1186/1471-2466-14-173) contains supplementary material, which is available to authorized users.
PMCID: PMC4228268  PMID: 25369941
Chronic obstructive pulmonary disease; SNP; ADAM33; Haplotype; Pulmonary function; Airway inflammatory process
20.  Effects of BMI, Fat Mass, and Lean Mass on Asthma in Childhood: A Mendelian Randomization Study 
PLoS Medicine  2014;11(7):e1001669.
In this study, Granell and colleagues used Mendelian randomization to investigate causal effects of BMI, fat mass, and lean mass on current asthma at age 7½ years in the Avon Longitudinal Study of Parents and Children (ALSPAC) and found that higher BMI increases the risk of asthma in mid-childhood.
Please see later in the article for the Editors' Summary
Observational studies have reported associations between body mass index (BMI) and asthma, but confounding and reverse causality remain plausible explanations. We aim to investigate evidence for a causal effect of BMI on asthma using a Mendelian randomization approach.
Methods and Findings
We used Mendelian randomization to investigate causal effects of BMI, fat mass, and lean mass on current asthma at age 7½ y in the Avon Longitudinal Study of Parents and Children (ALSPAC). A weighted allele score based on 32 independent BMI-related single nucleotide polymorphisms (SNPs) was derived from external data, and associations with BMI, fat mass, lean mass, and asthma were estimated. We derived instrumental variable (IV) estimates of causal risk ratios (RRs). 4,835 children had available data on BMI-associated SNPs, asthma, and BMI. The weighted allele score was strongly associated with BMI, fat mass, and lean mass (all p-values<0.001) and with childhood asthma (RR 2.56, 95% CI 1.38–4.76 per unit score, p = 0.003). The estimated causal RR for the effect of BMI on asthma was 1.55 (95% CI 1.16–2.07) per kg/m2, p = 0.003. This effect appeared stronger for non-atopic (1.90, 95% CI 1.19–3.03) than for atopic asthma (1.37, 95% CI 0.89–2.11) though there was little evidence of heterogeneity (p = 0.31). The estimated causal RRs for the effects of fat mass and lean mass on asthma were 1.41 (95% CI 1.11–1.79) per 0.5 kg and 2.25 (95% CI 1.23–4.11) per kg, respectively. The possibility of genetic pleiotropy could not be discounted completely; however, additional IV analyses using FTO variant rs1558902 and the other BMI-related SNPs separately provided similar causal effects with wider confidence intervals. Loss of follow-up was unlikely to bias the estimated effects.
Higher BMI increases the risk of asthma in mid-childhood. Higher BMI may have contributed to the increase in asthma risk toward the end of the 20th century.
Please see later in the article for the Editors' Summary
Editors' Summary
The global burden of asthma, a chronic (long-term) condition caused by inflammation of the airways (the tubes that carry air in and out of the lungs), has been rising steadily over the past few decades. It is estimated that, nowadays, 200–300 million adults and children worldwide are affected by asthma. Although asthma can develop at any age, it is often diagnosed in childhood—asthma is the most common chronic disease in children. In people with asthma, the airways can react very strongly to allergens such as animal fur or to irritants such as cigarette smoke, becoming narrower so that less air can enter the lungs. Exercise, cold air, and infections can also trigger asthma attacks, which can be fatal. The symptoms of asthma include wheezing, coughing, chest tightness, and shortness of breath. Asthma cannot be cured, but drugs can relieve its symptoms and prevent acute asthma attacks.
Why Was This Study Done?
We cannot halt the ongoing rise in global asthma rates without understanding the causes of asthma. Some experts think obesity may be one cause of asthma. Obesity, like asthma, is increasingly common, and observational studies (investigations that ask whether individuals exposed to a suspected risk factor for a condition develop that condition more often than unexposed individuals) in children have reported that body mass index (BMI, an indicator of body fat calculated by dividing a person's weight in kilograms by their height in meters squared) is positively associated with asthma. Observational studies cannot prove that obesity causes asthma because of “confounding.” Overweight children with asthma may share another unknown characteristic (confounder) that actually causes both obesity and asthma. Moreover, children with asthma may be less active than unaffected children, so they become overweight (reverse causality). Here, the researchers use “Mendelian randomization” to assess whether BMI has a causal effect on asthma. In Mendelian randomization, causality is inferred from associations between genetic variants that mimic the effect of a modifiable risk factor and the outcome of interest. Because gene variants are inherited randomly, they are not prone to confounding and are free from reverse causation. So, if a higher BMI leads to asthma, genetic variants associated with increased BMI should be associated with an increased risk of asthma.
What Did the Researchers Do and Find?
The researchers investigated causal effects of BMI, fat mass, and lean mass on current asthma at age 7½ years in 4,835 children enrolled in the Avon Longitudinal Study of Parents and Children (ALSPAC, a long-term health project that started in 1991). They calculated an allele score for each child based on 32 BMI-related genetic variants, and estimated associations between this score and BMI, fat mass and lean mass (both measured using a special type of X-ray scanner; in children BMI is not a good indicator of “fatness”), and asthma. They report that the allele score was strongly associated with BMI, fat mass, and lean mass, and with childhood asthma. The estimated causal relative risk (risk ratio) for the effect of BMI on asthma was 1.55 per kg/m2. That is, the relative risk of asthma increased by 55% for every extra unit of BMI. The estimated causal relative risks for the effects of fat mass and lean mass on asthma were 1.41 per 0.5 kg and 2.25 per kg, respectively.
What Do These Findings Mean?
These findings suggest that a higher BMI increases the risk of asthma in mid-childhood and that global increases in BMI toward the end of the 20th century may have contributed to the global increase in asthma that occurred at the same time. It is possible that the observed association between BMI and asthma reported in this study is underpinned by “genetic pleiotropy” (a potential limitation of all Mendelian randomization analyses). That is, some of the genetic variants included in the BMI allele score could conceivably also increase the risk of asthma. Nevertheless, these findings suggest that public health interventions designed to reduce obesity may also help to limit the global rise in asthma.
Additional Information
Please access these websites via the online version of this summary at
The US Centers for Disease Control and Prevention provides information on asthma and on all aspects of overweight and obesity (in English and Spanish)
The World Health Organization provides information on asthma and on obesity (in several languages)
The UK National Health Service Choices website provides information about asthma, about asthma in children, and about obesity (including real stories)
The Global Asthma Report 2011 is available
The Global Initiative for Asthma released its updated Global Strategy for Asthma Management and Prevention on World Asthma Day 2014
Information about the Avon Longitudinal Study of Parents and Children is available
MedlinePlus provides links to further information on obesity in children, on asthma, and on asthma in children (in English and Spanish
Wikipedia has a page on Mendelian randomization (note: Wikipedia is a free online encyclopedia that anyone can edit; available in several languages)
PMCID: PMC4077660  PMID: 24983943
21.  Mechanistic role of a disease-associated genetic variant within the ADAM33 asthma susceptibility gene 
BMC Medical Genetics  2007;8:46.
ADAM33 has been identified as an asthma-associated gene in an out-bred population. Genetic studies suggested that the functional role of this metalloprotease was in airway remodeling. However, the mechanistic roles of the disease-associated SNPs have yet to be elucidated especially in the context of the pathophysiology of asthma. One disease-associated SNP, BC+1, which resides in intron BC toward the 5' end of ADAM33, is highly associated with the disease.
The region surrounding this genetic variant was cloned into a model system to determine if there is a regulatory element within this intron that influences transcription.
The BC+1 protective allele did not impose any affect on the transcription of the reporter gene. However, the at-risk allele enforced such a repressive affect on the promoter that no protein product from the reporter gene was detected. These results indicated that there exists within intron BC a regulatory element that acts as a repressor for gene expression. Moreover, since SNP BC+1 is a common genetic variant, this region may interact with other undefined regulatory elements within ADAM33 to provide a rheostat effect, which modulates pre-mRNA processing. Thus, SNP BC+1 may have an important role in the modulation of ADAM33 gene expression.
These data provide for the first time a functional role for a disease-associated SNP in ADAM33 and begin to shed light on the deregulation of this gene in the pathophysiology of asthma.
PMCID: PMC1955437  PMID: 17640346
22.  Metalloproteinase-disintegrin ADAM12 is associated with a breast tumor-initiating cell phenotype 
Breast cancer research and treatment  2013;139(3):10.1007/s10549-013-2602-2.
Members of the ADAM family of proteases have been associated with mammary tumorigenesis. Gene profiling of human breast tumors identified several intrinsic subtypes of breast cancer, which differ in terms of their basic biology, response to chemotherapy/radiation, preferential sites of metastasis, and overall patient survival. Whether or not the expression of individual ADAM proteases is linked to a particular subtype of breast cancer and whether the functions of these ADAMs are relevant to the cancer subtype have not been investigated. We analyzed several transcriptomic datasets and found that ADAM12L is specifically up-regulated in claudin-low tumors. These tumors are poorly differentiated, exhibit aggressive characteristics, have molecular signatures of epithelial-tomesenchymal transition (EMT), and are rich in markers of breast tumor-initiating cells (BTICs). Consistently, we find that ADAM12L, but not the alternative splice variant ADAM12S, is a part of stromal, mammosphere, and EMT gene signatures, which are all associated with BTICs. In patients with estrogen receptor-negative tumors, high expression of ADAM12L, but not ADAM12S, is predictive of resistance to neoadjuvant chemotherapy. Using breast cancer cells, which express the endogenous ADAM12L and efficiently form mammospheres when plated at the density of single cell per well, we show that ADAM12L plays an important role in supporting mammosphere growth. We postulate that ADAM12L may serve as a novel marker and/or a novel therapeutic target in BTICs.
PMCID: PMC3844617  PMID: 23771733
Metalloprotease; Disintegrin; Claudin-low tumors; Tumor-initiating cells; Epithelial-to-mesenchymal transition; Mammospheres
23.  Association of ADAM33 gene polymorphisms with allergic asthma 
Asthma results from the interaction between genetic and environmental factors. ADAM33 gene on chromosome 20p13 is associated with asthma and airway hyperresponsiveness.
Materials and Methods:
This is a case-control study, where four SNPs S1 (rs3918396), T1 (rs2280091), T2 (rs2280090), V4 (rs2787094) of ADAM33 gene have been assessed in patients with allergic asthma and normal controls (95 patients and 86 normal). Blood samples of these participants have been genotyped by PCR and the RFLP method.
There was no association between asthmatic patients and polymorphisms of alleles, genotypes and haplotypes of the ADAM33 gene. When categorizing the asthmatic patients in severe, moderate and mild groups, associations in the subcategories of asthmatic patients were found. There were associations between polymorphisms of C allele of T1 SNP with severe asthmatic patients and G allele of V4 SNP with moderate asthmatics respectively (P=0.006, P=0.01). There was a significant association between sensitivity to mite and polymorphism of C allele of T1 SNP (P=0.02). Besides, there was a significant association between sensitivity to weeds and genotype GG of V4 SNP (P=0.05).
Polymorphisms of ADAM33 gene might be associated with severe asthma and sensitivity to aeroallergens in northeast of Iran, but further studies are needed to determine the polymorphisms in this area and other regions of our country.
PMCID: PMC4322157
ADAM33; Allergic asthma; Genetic; SNP
24.  A disintegrin and metalloprotease 33 and chronic obstructive pulmonary disease pathophysiology 
Thorax  2006;62(3):242-247.
Chronic obstructive pulmonary disease (COPD) is a respiratory disorder with increasing prevalence and mortality. It is associated with airway obstruction, increased airway hyper‐responsiveness (AHR), and ongoing airway and lung inflammation dominated by CD8 lymphocytes and neutrophils. Single‐nucleotide polymorphisms (SNPs) in a disintegrin and metalloprotease 33 (ADAM33) gene have been associated with AHR and COPD.
To assess whether SNPs in ADAM33 are associated with the severity of AHR and airway inflammation in COPD.
Eight SNPs in ADAM33 (F+1, Q‐1, S_1, S_2, ST+5, T_1, T_2, V_4) were genotyped in 111 patients with COPD (96 males, 69 current smokers, mean (standard deviation (SD)), aged 62 (8) years, median pack‐years 42 (IQR 31–55), mean postbronchodilator forced expiratory volume in 1 s (FEV1)% predicted 63 (9). Provocative concentration of methacholine causing a decrease in FEV1 of 20% (PC20 methacholine), sputum and bronchial biopsies were collected.
Patients with the ST+5 AA genotype had more severe AHR, higher numbers of sputum inflammatory cells and CD8 cells in bronchial biopsies than patients with the GG genotype (p = 0.03, 0.05 and 0.01, respectively). CD8 cell numbers were lower in patients carrying the minor allele of SNP T_1 and T_2, and homozygotic minor variants of SNP S_2 compared with the wild type (p = 0.02, 0.01 and 0.02, respectively).
This is the first study revealing that SNPs in a gene that confers susceptibility to COPD in the general population—that is, ADAM33—are associated with AHR and airway inflammation in COPD. These findings constitute an important step forward in linking gene polymorphisms with COPD pathophysiology, thereby possibly contributing to better treatments for this progressive and disabling disease in the future.
PMCID: PMC2117167  PMID: 17090574
25.  Association Study on ADAM33 Polymorphisms in Mite-Sensitized Persistent Allergic Rhinitis in a Chinese Population 
PLoS ONE  2014;9(4):e95033.
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.
To assess whether the ADAM33 polymorphisms are associated with persistent allergic rhinitis (PER) due to house dust mites in a Chinese population.
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.
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).
Polymorphisms in the ADAM33 gene may contribute to susceptibility of mite-sensitized PER in this Chinese population.
PMCID: PMC3994017  PMID: 24751681

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