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Pharmacologic studies have revealed that cysteinyl leukotrienes (CYSLTs) act through two receptors, cysteinyl leukotriene receptor 1 (CYSLTR1) and CYSLTR2. CYSLTR1 antagonists are widely used to treat asthma and rhinitis. In this study, we characterized the genomic structure and transcriptional regulation of CYSLTR1 and examined associations between CYSLTR1 polymorphisms and asthma/rhinitis. The experiment of rapid amplification of cDNA end revealed that CYSLTR1 contains three exons and that the entire open reading frame is located in exon 3. Reverse transcriptase-polymerase chain reaction showed that there were multiple splice variants of CYSLTR1 and that the transcript expression patterns differed from tissues and cell types. The promoter region of CYSLTR1 is from -665 to -30 bp relative to the transcription start site. We identified four polymorphisms (c.-618-434T/C, c.-618-275C/A, c.-618-136G/A, and 927C/T), and transmission disequilibrium tests revealed that none of these polymorphisms was associated with the development of asthma/rhinitis. However, the TCG and CAA haplotypes in the promoter region caused different transcriptional activity. Our findings indicate that CYSLTR1 polymorphisms are not likely to be involved in the development of asthma/rhinitis, but it is possible that these polymorphisms could influence drug responses in individuals with atopic diseases.

Background: CD14 is an essential component of the receptor for lipopolysaccharide (LPS). LPS stimulates T-helper type 1 (Th1) cytokine expression, potentially suppressing Th2 immune responses involved in IgE-mediated allergic diseases. Previous studies have reported that -159C/T, a promoter polymorphism of CD14, is associated with total serum IgE levels and atopy, but other studies have shown conflicting results., Methods: To examine possible associations of CD14 polymorphisms with asthma susceptibility, we performed transmission disequilibrium tests (TDTs) of 137 Japanese families identified through children with atopic asthma., Results: We found no association between -159C/T polymorphism and asthma (p= 0.37). Quantitative TDT and ANOVA showed no association between the -159C/T genotype and total serum IgE levels. We also performed a meta-analysis of data from all available studies. Neither a fixed-effects model nor a random-effect model showed a significant odds ratio for the -159C/T polymorphism (p > 0.1)., Conclusions: Our data indicate that CD14 does not contribute substantially to susceptibility to asthma. Further studies examining both genotypes and environmental factors will be necessary to elucidate the role of CD14 in the development of allergic diseases.

Tumor necrosis factor (TNF) is a potent inflammatory cytokine that contributes to airway inflammation in asthma. Previous studies have reported that a G-to-A transition at position -308 (-308G/A, also referred to as TNF-alpha-308*1 and 308*2 respectively), is associated with asthma, but other studies have shown conflicting results. To investigate a possible association between the TNF-308G/A polymorphism and asthma, we performed transmission disequilibrium tests and a case-control study (family samples: 495 members in 165 Japanese trio families with one asthmatic child and both parents; case-control samples: 461 Japanese asthmatic children and 465 healthy controls). To increase the sample size and power, we performed a meta-analysis of all available relevant studies, including 2,477 asthmatics and 3,217 controls. We did not find a significant association between the TNF-308G/A polymorphism and childhood atopic asthma in two independent Japanese populations (P>0.05); however, meta-analysis revealed that the TNF-308G/A polymorphism was statistically significantly associated with asthma. The combined odds ratio with a fixed effects model and with a random effects for TNF-308A was 1.46 (95% confidence interval [CI], 1.27-1.68, P=0.0000001) and 1.46 (95% CI, 1.20-1.77, P=0.00014) respectively. Our data further support the importance of the TNF region in the development of asthma.

Rationale: Asthma is a common respiratory disease with complex genetic components. We previously reported strong evidence for linkage between mite-sensitive asthma and markers on chromosome 5q33. This area of linkage includes a region homologous to a mouse area that contains a locus involved in regulation of airway hyperreactivity., Objective: The aim of the present study is to identify asthma susceptibility genes on chromosome 5q33., Methods and Results: We performed mutation screening and association analyses of genes in the 9.4-Mb human linkage region. Transmission disequilibrium test analysis of 105 polymorphisms in 155 families with asthma revealed that six polymorphisms in cytoplasmic fragile X mental retardation protein (FMRP)-interacting protein 2 gene were associated significantly with the development of asthma (p = 0.000075; odds ratio, 5.9). These six polymorphisms were in complete linkage disequilibrium. In real-time quantitative polymerase chain reaction analysis, subjects homozygous for the haplotype overtransmitted to asthma-affected offspring showed significantly increased level of cytoplasmic FMRP interacting protein 2 gene expression in lymphocytes compared with ones heterozygous for the haplotype (p = 0.038)., Conclusions: Our data suggest that cytoplasmic FMRP interacting protein 2 are associated with the development of atopic asthma in humans, and that targeting cytoplasmic FMRP interacting protein 2 could be a novel strategy for treating atopic asthma.

Objective: Cysteinyl leukotriene receptor 2 (CYSLTR2) is one of the receptors for the cysteinyl leukotrienes (CYSLTs), which cause bronchoconstrictions, vascular hyperpermeability and mucus hypersecretion in asthmatic patients. CYSLTR1 antagonists have been shown to be effective in the treatment of chronic asthma. CYSLTR2 is located approximately 300 kb from D13S153, which is reportedly linked to asthma in several populations. We characterized the genomic structure of humans CYSLTR2, determined the putative major promoter region and conducted association studies pertaining to polymorphisms in CYSLTR2 and asthma., Methods and Results: We identified three novel exons in the 5' untranslated region of CYSLTR2 by rapid amplification of cDNA ends and identified eight novel polymorphisms in CYSLTR2 by direct sequencing. A transmission disequilibrium test with 137 Japanese asthmatic families revealed that the -1220A > C polymorphism is associated with the development of asthma (P = 0.0066). In addition, a polymorphism in the putative promoter region caused different promoter activities in vitro., Conclusion: Our results suggest that CYSLTR2 is one of the genes that contributes to susceptibility to asthma in the Japanese population.

Background: The beta(2)-adrenergic receptor (ADRB2) is the most common adrenergic receptor in the lung, and associations between ADRB2 polymorphisms and intermediate phenotypes of asthma have been reported. Four missense polymorphisms (Arg16Gly, Gln27Glu, Val34Met, and Thr164Ile) and one polymorphism in the 5' leader cistron of the ADRB2 messenger RNA has been identified. In vitro studies have shown that these missense polymorphisms can affect ADRB2 function., Methods: To examine possible associations of ADRB2 polymorphisms with asthma susceptibility, we performed transmission disequilibrium tests (TDT) of 137 Japanese families identified through children with atopic asthma., Results: We did not find associations between any alleles of the ADRB2 polymorphisms and asthma by TDT (p > 0.1). We also performed a meta-analysis of data from all available studies. The random-effects model showed no significant odds ratio for the Arg16Gln (odds ratio = 1.05, p = 0.53) or Gln27Glu (odds ratio = 1.12, p = 0.22) polymorphism., Conclusion: Our data indicate that ADRB2 does not contribute substantially to susceptibility to asthma, but it is possible that these polymorphisms influence disease activity and drug responses in individuals with asthma., (Copyright 2004 S. Karger AG, Basel)

Asthma is characterized by reversible airway obstruction and airway inflammation. Serum levels of eosinophil cationic protein (ECP) might reflect eosinophilic airway inflammation and asthma activity. However, serum ECP levels are not elevated in some patients with asthma, even when they are symptomatic. In this study, we screened for polymorphisms in the ECP gene and analyzed association between these polymorphisms and asthma and serum ECP levels in 137 Japanese families identified through children with asthma. We identified three polymorphisms (-393C/T, -38C/A, and 124Arg/Thr) in human ECP. We did not find associations between these polymorphisms and asthma by the transmission disequilibrium test. However, we found that serum ECP levels in subjects with the -393T allele were significantly lower than those in subjects with the -393C allele. A reporter construct with the -393T allele showed significantly lower promoter activity than one with the -393C allele. Gel shift assay revealed that C/EBP proteins can bind the -393C/T polymorphic site. These data indicate that C/EBP proteins play an important role in the regulation of ECP and that a significant amount of the variance in baseline serum ECP levels may be explained by the -393C/T polymorphism. Although ECP polymorphisms are not likely to be involved in the development of asthma, measurement of ECP levels for the assessment of asthma activity may be improved when done in combination with genotyping of the -393C/T polymorphism.

Tumor necrosis factor (TNF) is a proinflammatory cytokine that participates in the inflammatory reaction in patients with asthma. The TNFA and TNFB genes, which encode TNF-alpha and TNF-beta, respectively, are located within the region encoding the human major histocompatibility complex on chromosome 6p21.3, which showed linkage to atopic asthma in our genome-wide search. To determine whether polymorphisms in the 5' flanking region of the TNFA gene (-1031C/T, -863C/A, and -857C/T) and an NcoI polymorphism in the TNFB gene (LTA NcoI) are associated with the development of asthma, we performed transmission disequilibrium tests of families identified through children with atopic asthma. Genotypes of families were determined by polymerase chain reaction-based restriction fragment length polymorphism or SNaPshot analysis. Transmission disequilibrium tests of 144 asthmatic families revealed that transmission of the -857C allele and the -1031T-863C-857C haplotype in the TNFA gene to asthma-affected offspring occurred more frequently than expected (-857C allele, p = 0.0055; -1031T-863C-857C haplotype, p = 0.0002). Our results suggest that TNFA or nearby genes, including those in the major histocompatibility complex region, may contribute to the development of asthma in the Japanese population.

Platelet-activating factor (PAF), which has been implicated in the pathophysiology of inflammation in asthma, is degraded and inactivated by PAF acetylhydrolase (PAFAH). Approximately 4% of the Japanese population lacks plasma PAFAH due to a loss-of-function variant (Val279Phe) in the PAFAH gene. Although lack of PAFAH activity is thought to be a risk factor for asthma, there are conflicting findings concerning association between the Val279Phe variant and asthma. In this study, we conducted transmission disequilibrium tests of 118 Japanese parent-child trios identified through mite-sensitive atopic asthmatic children. A case-control study was also carried out. The Phe279/Phe279 genotype was found more frequently in children with atopic asthma (13%) than in their parents (6%) or in controls (4%). Results of the genotypic transmission test were significant, and the Phe279/Phe279 genotype was transmitted preferentially to asthmatic children. Our data support an association between deficiency in PAFAH activity and atopic asthma.

Background: Asthma is a complex phenotype that is influenced by both genetic and environmental factors. Genome-wide linkage and association studies have been performed to identify susceptibility genes for asthma. These studies identified new genes and pathways implicated in this disease, many of which were previously unknown. Objective: To perform a large-scale genotyping study to identify asthma-susceptibility genes in the Japanese population. Methods: We performed a large-scale, three-stage association study on 288 atopic asthmatics and 1032 controls, by using multiplex PCR-Invader assay methods at 82,935 single nucleotide polymorphisms (SNPs) (1st stage). SNPs that were strongly associated with asthma were further genotyped in samples from asthmatic families (216 families, 762 members, 2nd stage), 541 independent patients, and 744 controls (3rd stage). Results: SNPs located in the 5' region of PEX19 (rs2820421) were significantly associated with P < 0.05 through the 1st to the 3rd stage analyses; however, the P values did not reach statistically significant levels (combined, P = 3.8 x 10-5; statistically significant levels with Bonferroni correction, P = 6.57 x 10-7). SNPs on HPCAL1 (rs3771140) and on IL18R1 (rs3213733) were associated with asthma in the 1st and 2nd stage analyses, but the associations were not observed in the 3rd stage analysis. Conclusion: No association attained genome-wide significance, but several loci for possible association emerged. Future studies are required to validate these results for the prevention and treatment of asthma. [ABSTRACT FROM AUTHOR]

Pharmacologic studies have revealed that cysteinyl leukotrienes (CYSLTs) act through two receptors, cysteinyl leukotriene receptor 1 (CYSLTR1) and CYSLTR2. CYSLTR1 antagonists are widely used to treat asthma and rhinitis. In this study, we characterized the genomic structure and transcriptional regulation of CYSLTR1 and examined associations between CYSLTR1 polymorphisms and asthma/rhinitis. The experiment of rapid amplification of cDNA end revealed that CYSLTR1 contains three exons and that the entire open reading frame is located in exon 3. Reverse transcriptase-polymerase chain reaction showed that there were multiple splice variants of CYSLTR1 and that the transcript expression patterns differed from tissues and cell types. The promoter region of CYSLTR1 is from −665 to −30 bp relative to the transcription start site. We identified four polymorphisms (c.-618-434T/C, c.-618-275C/A, c.-618-136G/A, and 927C/T), and transmission disequilibrium tests revealed that none of these polymorphisms was associated with the development of asthma/rhinitis. However, the TCG and CAA haplotypes in the promoter region caused different transcriptional activity. Our findings indicate that CYSLTR1 polymorphisms are not likely to be involved in the development of asthma/rhinitis, but it is possible that these polymorphisms could influence drug responses in individuals with atopic diseases. [ABSTRACT FROM AUTHOR]