Associations of BRAP polymorphisms with the risk of alcohol dependence and scores on the Alcohol Use Disorders Identification Test.

BACKGROUND: Alcohol dependence (AD) is a common disorder that is influenced by genetic as well as environmental factors. A previous genome-wide association study (GWAS) of the Korean population performed by our research group identified a number of genes, including BRCA1-associated protein (BRAP) and protein arginine methyltransferase 8 (PRMT8), as novel genetic markers of AD. METHODS: The present investigation was a fine-mapping follow-up study of 459 AD and 455 non-AD subjects of Korean descent to determine the associations between BRAP and PRMT8 polymorphisms and AD. The Alcohol Use Disorders Identification Test (AUDIT) was administered to screen for the degree of AD risk in the subjects and 58 genetic variants, 5 for BRAP and 53 for PRMT8, were genotyped for subsequent association analyses. RESULTS: In the present case-control analysis, BRAP rs3782886 showed the most significant association signal with a risk of AD (P=1.29×10-16, Pcorr =7.74×10-16, OR =0.19). There were also significant differences in the overall and subcategory scores for the BRAP genetic variants, including rs3782886 (P=9.94×10-31, Pcorr =5.96×10-30 at rs3782886 for the overall AUDIT score). However, the genetic effects of PRMT8 polymorphisms observed in our previous GWAS were not replicated in the present study (minimum P=0.0005, Pcorr >0.05, OR =0.30 at rs4766139 in the recessive model). Furthermore, the single-nucleotide polymorphisms of PRMT8 were not associated with the overall and subcategory AUDIT scores. CONCLUSION: The present findings suggest that the genetic variants of BRAP may contribute to a predisposition for an alcohol use disorder.

Association between TAAR6 polymorphisms and airway responsiveness to inhaled corticosteroids in asthmatic patients.

BACKGROUND: Genetic polymorphisms may be responsible for the wide variation in response to inhaled corticosteroids in asthmatic patients. We had previously reported that one polymorphism rs7772821, located on the 3'-UTR of trace amine-associated receptor 6 (TAAR6), is significantly associated with percentile changes in the forced expiratory volume in 1 s (%ΔFEV1) after inhaled corticosteroid treatment in asthmatics using a genome-wide association study. The aim of the present study was to validate the association between 15 single-nucleotide polymorphisms (SNPs) on the TAAR6 and airway responsiveness to inhaled corticosteroids in the asthmatics. METHODS: The %ΔFEV1 induced by 4 weeks' treatment with inhaled fluticasone propionate (1000 µg daily) was measured in 246 asthmatics. The 15 SNPs of TAAR6 were genotyped using a TaqMan assay. An association analysis between %ΔFEV1 and TAAR6 polymorphisms was carried out using a linear regression model controlling for age, sex, smoking status, presence of atopy, and baseline FEV1 as covariates. RESULTS: Among the 15 SNPs and seven haplotypes of TAAR6, rs7772821 (T>G) on the 3'-UTR showed the strongest correlation with inhaled corticosteroid-induced %ΔFEV1 (Pcorr=0.002 in the codominant model, Pcorr=0.03 in the dominant model, Pcorr=0.01 in the recessive model). The %ΔFEV1 of the rs7772821T>G minor homozygotes (60.77%) was higher than that of patients harboring either the rs7772821 T/G or T/T genotypes (21.32 and 31.60%, respectively). CONCLUSION: The TAAR6 rs7772821 polymorphism may be one of the important genetic factors for predicting the response to treatment with inhaled corticosteroids in asthmatics.

Association of 5-hydroxytryptamine (serotonin) receptor 4 (5-HTR4) gene polymorphisms with asthma.

BACKGROUND AND OBJECTIVE: The neurotransmitter, 5-hydroxytryptamine, acts as an immunomodulator by stimulating the release of inflammatory cytokines and regulating the function of dendritic cells and monocytes. The 5-hydroxytryptamine receptor 4 (HTR4) gene is located in a region previously linked to an increased risk of asthma and atopy. The aim of this study was to investigate the association between HTR4 and asthma. METHODS: Thirty-two single nucleotide polymorphisms (SNP) in HTR4 were investigated by direct sequencing of 24 DNA samples from unrelated Korean subjects. RESULTS: The 32 genetic variants comprised 22 intronic SNP, two SNP in the 3'-untranslated region (exon 7) and eight SNP in the 3'-downstream region. Logistic regression analysis showed that two intronic polymorphisms were significantly associated with the risk of asthma. Two minor HTR4 alleles, +142828G>A and +122769G>A, occurred at significantly higher frequencies in the asthmatic group than in the healthy control group (49.59% vs 42.29%, P=0.003, and 47.99% vs 40.35%, P=0.008, respectively), and these differences remained significant after correction for multiple testing (P=0.05, dominant mode of inheritance; and P=0.03, dominant mode, respectively). Haplotype analysis revealed three haplotype blocks. The frequency of haplotype 1 in block 2 was significantly higher in asthmatics (P=0.003, dominant mode), whereas the frequency of haplotype 4 in block 3 was significantly lower in asthmatics (P=0.0009, dominant mode). CONCLUSIONS: SNP and haplotypes of the HTR4 gene were associated with the asthma phenotype and genetic variation of HTR4 may affect susceptibility to the development of asthma.

The association of a single-nucleotide polymorphism of the IL-2 inducible T-cell Kinase gene with asthma.

Asthma manifests as TH2-dominant airway inflammation regulated by inducible T-cell kinase (ITK). To investigate associations between genetic variants of the ITK gene and asthma, 31 single-nucleotide polymorphisms (SNPs) were genotyped in 303 normal controls and 498 asthmatics and the two groups were compared using logistic regression models. The functional effects of the ITK promoter SNP were assessed using pGL3 luciferase reporter systems and gel-shift assays. The minor allele-196C>T in the promoter region of the ITK gene was significantly more frequent in asthmatics than in controls. The luciferase activity of the PGL3-ITK-196T allele construct was higher than that of the -196C allele. In the gel-shift assay, -196T double-stranded oligonucleotides bound more strongly to Jurkat cell nuclear protein compared to the -196C double-stranded oligonucleotides. People with the -rare allele 196C>T may be more susceptible to asthma via transcriptional regulation of the ITK gene.

Association of IKBA gene polymorphisms with the development of asthma.

Nuclear factor-κB (NF-κB) orchestrates the expression of genes responsible for airway inflammation and remodeling in asthma. The activity of NF-κB is tightly regulated by IKBA, which may be modulated by genetic polymorphisms of the IKBA gene. We investigated the association between asthma susceptibility and IKBA gene polymorphisms in a Korean population. Genotyping was performed in BA (bronchial asthma) and NC (normal control). We measured reverse transcription-polymerase chain reaction (RT-PCR), enzyme-linked immunosorbent assay, and luciferase reporter assays, respectively. A -673A>T (rs2233407) was associated with asthma development in subjects with atopic asthma (odds ratio = 0.56, p = 0.004). The IKBA mRNA level was higher in B-cell lines with the rs2233407 TT genotype compared with those with the AA genotype (p = 0.024). The luciferase activity of the rs2233407 T genotype was higher than that of the A (p = 0.002). The cytoplasmic levels of total IKBA and IKBA [p-S32] were higher in B cell lines of the rs2233407 TT genotype than those of the AA (p = 0.016 and p = 0.036, respectively), whereas nuclear NF-κB activity in cells with the IKBA rs2233407 AA genotype was higher than in cells with the AA (p = 0.038). The IKBA rs2233407 A>T polymorphism may predispose individuals to the development of atopic asthma via regulation of IKBA gene expression at the transcriptional level.

Association of CCR2 polymorphisms with the number of closed coronary artery vessels in coronary artery disease.

Coronary artery disease (CAD) is one of the most common forms of heart disease. It has been demonstrated that chemokine-mediated inflammation is associated with the development of CAD. In this study, in order to determine the role of CCR2, a receptor for MCP-1, in the development of CAD, we initially sequenced and identified the genetic variants of CCR2 using 24 unrelated Korean individuals' DNA samples. A total of 13 genetic variants, including 1 deletion and 12 SNPs, were identified in the Korean population. Although we could not detect any association of CCR2 polymorphic markers with CAD, several SNP markers of CCR2 gene showed highly significant signals with the number of arteries with significant coronary artery stenosis in the CAD male patients. The most significant signal was detected at the SNP located at exon 2 (+780T>C, Asn260Asn) CI: 1.19-1.87, P=0.0005 (odds ratio: 1.49, 95% CI: 1.19-1.87, p=0.0005) (Table 3). This result indicates that CCR2 can play a role in the pathogenesis of CAD, especially to the number of vessels in CAD.

TNF-alpha (-308 G/A) and CD14 (-159T/C) polymorphisms in the bronchial responsiveness of Korean children with asthma.

BACKGROUND: TNF-alpha is a pivotal proinflammatory cytokine increased in asthmatic airways. The TNF-alpha gene family might be linked to asthma or bronchial hyperresponsiveness (BHR), and TNF-alpha production might be modulated by CD14(+) cells. OBJECTIVE: We investigated the association between asthma susceptibility or asthma-related phenotypes and TNF-alpha (-308G/A) polymorphism and examined the combined effect with CD14 (-159T/C) polymorphism in Korean children. METHODS: Asthmatic (n = 788) and control (n = 153) children were evaluated for asthma phenotypes. Genotypes were determined by using the single-base extension method and PCR-restriction fragment length polymorphism. RESULTS: There was no difference between asthmatic children and control subjects in terms of the allele frequencies of TNF-alpha (-308G/A) and CD14 (-159T/C). Significantly lower PC(20) values were seen in asthmatic (P = .016) children with the TNF-alpha risk allele (-308A). Higher frequencies of 1 or 2 copies of the risk allele were found in asthmatic children with moderate-to-severe BHR to methacholine and exercise compared with control children (adjusted odds ratio of 2.57 [95% CI, 1.30-5.08] and adjusted odds ratio of 2.04 [95% CI 0.99-4.20], respectively). In addition, asthmatic children with risk alleles at both loci had significantly greater BHR than those homozygous for the common alleles (P = .018). CONCLUSION: The TNF-alpha promoter polymorphism (-308G/A) might be associated with severe BHR in Korean children with asthma. In addition, these children show a synergistic effect between the TNF-alpha promoter (-308A) and CD14 promoter (-159C) polymorphisms in terms of BHR. CLINICAL IMPLICATIONS: The TNF-alpha polymorphism might be a disease-modifying gene in asthma and modulated by the CD14 gene.

Association analysis of CD40 polymorphisms with asthma and the level of serum total IgE.

RATIONALE: The CD40 protein plays important roles in cell-mediated and humoral immune responses, especially in immunoglobulin class-switching to IgE. OBJECTIVES: We tested the association of CD40 polymorphisms with the risk of asthma and the level of serum IgE and investigated the functional effect of associated polymorphisms on the expression of CD40. METHODS: We identified 17 CD40 single-nucleotide polymorphisms (SNPs) in the Korean population by direct sequencing, and we genotyped 7 of these in 487 subjects with asthma and in 161 normal subjects. Cell-surface expression of CD40 for B-cell lines of various SNP genotypes was measured using flow cytometry. The effects of SNPs in the promoter and 5'-untranslated regions (UTRs) of CD40 were assessed using pGL3 luciferase and enhanced green fluorescent protein (EGFP) reporter systems, respectively. MEASUREMENTS AND RESULTS: None of the SNPs was associated with asthma risk, but total serum IgE levels were associated with the -580G>A and -1C>T polymorphisms in subjects with asthma (p = 0.007 and 0.005, respectively). The total amount of IgE was highest in the -580A or -1C homozygotes. More CD40 was expressed in B cells with the -1C allele than in those with the -1T allele (p < 0.001). EGFP expression from the CD40 5'-UTR-EGFP construct was higher for the -1C allele than the -1T allele. The -580G>A SNP did not affect promoter activity, even after IFN-gamma stimulation. CONCLUSIONS: CD40 gene polymorphisms exert a genetic effect on IgE production in patients with asthma through translational regulation of CD40 expression on B cells.

Lack of association of glutathione S-transferase P1 Ile105Val polymorphism with aspirin-intolerant asthma.

BACKGROUND: Glutathion S-transferase P1 (GSTP1), the abundant isoform of glutathione S-transferase in lung epithelium, plays an important role in cellular protection against oxidative stress and toxic foreign chemicals. GSTP1 (Ile105Val) polymorphism has been reported to be associated with asthma related phenotypes such as atopy and bronchial hyperresponsiveness. Therefore we investigated whether this polymorphism may be associated with the development of aspirin-intolerant asthma (AIA). METHODS: GSTP1 Ile105Val polymorphism was determined using a single based extension method in 88 AIA subjects and compared to 154 aspirin-tolerant asthma (ATA) subjects and 119 normal healthy controls (NC) recruited from the Korean population. RESULTS: No significant differences in allele and genotype frequencies of the GSTP1 Ilel105Val polymorphism were observed in the three groups (p>0.05). However, minor G allele frequency of the GSTP1 Ilel105Val polymorphism in AIA group (16.5%) tended to be lower than in the NC group (20.6%). CONCLUSION: These results suggest a lack of association of the GSTPI Ilel105Val gene polymorphism with AIA phenotype in the Korean population [word count: 159].