Biomedical subjects

Michaela Schedel

Publications and source records attributed to Michaela Schedel.

4 recordsLinked to original sources

PubMed2006

The role of polymorphisms in ADAM33, a disintegrin and metalloprotease 33, in childhood asthma and lung function in two German populations.

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

ADAM Proteins↗

PubMed2006

IL-4/IL-13 pathway genetics strongly influence serum IgE levels and childhood asthma.

BACKGROUND: IgE production, a hallmark of asthma and atopic disease, may be under genetic control. Genes of the IL-4 and IL-13 pathway, central for IgE regulation, have so far only been assessed in studies of single gene effects. OBJECTIVE: Here we analyzed combined extended haplotypes involving IL-4, IL-13, their shared receptor chain IL-4Ralpha, and the intracellular signal transducer and activator of transcription, STAT6, to assess the combined effect of single nucleotide polymorphisms in this important immunological signaling pathway. METHODS: We genotyped a large cross-sectional population of 1120 children age 9 to 11 years for 18 polymorphisms in the respective genes of the IL-4/IL-13 pathway. One polymorphism per gene was selected because of its putative functional role, and extended haplotypes were built in a stepwise procedure where gene-by-gene interactions were assessed by using a Cordell model. RESULTS: Combining polymorphisms in all 4 major pathway genes in a stepwise procedure, the risk for high serum IgE levels increased 10.8-fold (P = .02) and the risk for the development of asthma increased by a factor of 16.8-fold (P = .005) compared with the maximum effect of any single polymorphism. Significant interactions in a model with additive and dominant effects, for both pair and triplet combinations for asthma (lowest P = .005), and for pairs of polymorphisms in IgE regulation were observed (lowest P = .054). CONCLUSION: These data indicate that only the combined analyses of genetic alterations in the IL-4/IL-13 pathway reveal its actual significance to the development of atopy and childhood asthma.

Asthma↗

PubMed2005

NOD1 variation, immunoglobulin E and asthma.

Asthma is a familial inflammatory disease of the airways of the lung. Microbial exposures in childhood protect against asthma through unknown mechanisms. The innate immune system is able to identify microbial components through a variety of pattern-recognition receptors (PRRs). NOD1 is an intracellular PRR that initiates inflammation in response to bacterial diaminopimelic acid (iE-DAP). The NOD1 gene is on chromosome 7p14, in a region that has been genetically linked to asthma. We carried out a systematic search for polymorphism in the gene. We found an insertion-deletion polymorphism (ND(1)+32656) near the beginning of intron IX that accounted for approximately 7% of the variation in IgE in two panels of families (P<0.0005 in each). Allele*2 (the insertion) was associated with high IgE levels. The same allele was strongly associated with asthma in an independent study of 600 asthmatic children and 1194 super-normal controls [odds ratio (OR) 6.3; 95% confidence interval (CI) 1.4-28.3, dominant model]. Differential binding of the two ND(1)+32656 alleles was observed to a protein from nuclei of the Calu 3 epithelial cell line. In an accompanying study, the deletion allele (ND(1)+32656*1) was found to be associated with inflammatory bowel disease. The results indicate that intracellular recognition of specific bacterial products affects the presence of childhood asthma.

Adaptor Proteins, Signal Transducing↗

PubMed2004

A signal transducer and activator of transcription 6 haplotype influences the regulation of serum IgE levels.

BACKGROUND: Because of its central role in the IL-4/IL-13 pathway, the intracellular signaling molecule signal transducer and activator of transcription 6 ( STAT6 ) may be crucial for IgE production in asthma and allergy. OBJECTIVE: We analyzed the association between polymorphisms in the STAT6 gene and the regulation of serum IgE levels. Methods In a population of 1120 German schoolchildren (age 9-11 years), we genotyped 6 previously identified polymorphisms spanning the STAT6 gene by using the matrix-assisted laser desorption ionization-time of flight mass spectrometry method. Haplotypes were estimated and population-derived IgE percentiles (50% IgE > 60 IU/mL, 66% IgE > 115 IU/mL, and 90% IgE > 457 IU/mL) were modeled as outcome variables in haplotype-trend regression analysis. RESULTS: Polymorphisms located in intron 2 (C2892T) and the 3' untranslated region (T12888C) significantly and consistently contributed to elevated total serum IgE levels. One STAT6 haplotype showed increased odds ratios of 1.58 (95% CI, 1.08-2.32; P = .020), 1.82 (95% CI, 1.19-2.77; P = .006), and 3.92 (95% CI, 1.93-7.96; P = .0002) for elevated IgE levels at percentiles 50%, 66%, and 90%, respectively. Because C2892T is located within a nuclear factor kappaB transcription factor binding site, a functional role of this polymorphism is very likely. CONCLUSION: The data indicate that within the IL-4/IL-13 pathway, genetic variants in the STAT6 gene significantly contribute to the regulation of serum IgE levels.

Base Sequence↗