GAREM1 regulates the PR interval on electrocardiograms.

PR interval is the period from the onset of P wave to the start of the QRS complex on electrocardiograms. A recent genomewide association study (GWAS) suggested that GAREM1 was linked to the PR interval on electrocardiograms. This study was designed to validate this correlation using additional subjects and examined the function of Garem1 in a mouse model. We analyzed the association of rs17744182, a variant in the GAREM1 locus, with the PR interval in 5646 subjects who were recruited from 2 Korean replication sets, Yangpyeong (n = 2471) and Yonsei (n = 3175), and noted a significant genomewide association by meta-analysis (P = 2.39 × 10-8). To confirm the function of Garem1 in mice, Garem1 siRNA was injected into mouse tail veins to reduce the expression of Garem1. Garem1 transcript levels declined by 53% in the atrium of the heart (P = 0.029), and Garem1-siRNA injected mice experienced a significant decrease in PR interval (43.27 ms vs. 44.89 ms in control, P = 0.007). We analyzed the expression pattern of Garem1 in the heart by immunohistology and observed specific expression of Garem1 in intracardiac ganglia. Garem1 was expressed in most neurons of the ganglion, including cholinergic and adrenergic cells. We have provided evidence that GAREM1 is involved in the PR interval of ECGs. These findings increase our understanding of the regulatory signals of heart rhythm through intracardiac ganglia of the autonomic nervous system and can be used to guide the development of a therapeutic target for heart conditions, such as atrial fibrillation.

Comparison of genetic variations of the SLCO1B1, SLCO1B3, and SLCO2B1 genes among five ethnic groups.

Organic anion-transporting polypeptide (OATP; gene symbol, SLCO) transporters are generally involved in the uptake of multiple drugs and their metabolites at most epithelial barriers. The pattern of single-nucleotide polymorphisms (SNPs) in these transporters may be determinants of interindividual variability in drug disposition and response. The objective of this study was to define the distribution of SNPs of three SLCO genes, SLCO1B1, SLCO1B3, and SLCO2B1, in a Korean population and other ethnic groups. The study was screened using the Illumina GoldenGate assay for genomic DNA from 450 interethnic subjects, including 11 pharmacogenetic core variants and 76 HapMap tagging SNPs. The genotype distribution of the Korean population was similar to East Asian populations, but significantly different from African American and European American cohorts. These interethnic differences will be useful information for prospective studies, including genetic association and pharmacogenetic studies of drug metabolism by SLCO families.

Association analysis of PDE4B polymorphisms with schizophrenia and smooth pursuit eye movement abnormality in a Korean population.

Schizophrenia is a debilitating mental disorder with a high heritability rate. Located on chromosome 1p31.3, the human cAMP-specific 3',5'-cyclic phosphodiesterase 4B (PDE4B) gene has been considered as an important candidate gene for the risk of schizophrenia. Several genetic association studies reported the association between PDE4B polymorphisms and the risk of schizophrenia in Caucasian, African American, Indian, and Japanese populations. The aim of this study is to examine the association of PDE4B variations with schizophrenia and smooth pursuit eye movement (SPEM) abnormality in a Korean population. A case-control association analysis was carried out by comparing the genotype distribution of eight PDE4B polymorphisms between 457 schizophrenia patients and 386 normal healthy subjects. Differences in the frequency distribution of PDE4B single nucleotide polymorphisms (SNPs) and haplotypes were analyzed by logistic regression analyses controlling for age as a covariate. Statistical analyses revealed nominal significant associations of rs1040716, rs472952, rs1321177, and rs2144719 with the risk of schizophrenia (p = 0.02~0.05). The rs11208756 polymorphism showed a nominal significant association with SPEM abnormality (p = 0.05). In a meta-analysis with Japanese and Korean populations, three SNPs (rs472952, rs1040716, and rs2180335) revealed significant associations with schizophrenia (meta-p value = 0.0038~0.019). Our results support previously reported association of PDE4B variations with schizophrenia in other populations. The findings in this study add a new evidence for the involvement of PDE4B gene in schizophrenia etiology.

Wnt5a is associated with cigarette smoke-related lung carcinogenesis via protein kinase C.

Wnt5a is overexpressed during the progression of human non-small cell lung cancer. However, the roles of Wnt5a during smoking-related lung carcinogenesis have not been clearly elucidated. We investigated the associations between Wnt5a and the early development of cigarette smoke related lung cancer using human bronchial epithelial (HBE) cells (NHBE, BEAS-2B, 1799, 1198 and 1170I) at different malignant stages established by exposure to cigarette smoke condensate (CSC). Abnormal up-regulation of Wnt5a mRNA and proteins was detected in CSC-exposed transformed 1198 and tumorigenic 1170I cells as compared with other non-CSC exposed HBE cells. Tumor tissues obtained from smokers showed higher Wnt5a expressions than matched normal tissues. In non-CSC exposed 1799 cells, treatment of recombinant Wnt5a caused the activations of PKC and Akt, and the blockage of Wnt5a and PKC significantly decreased the viabilities of CSC-transformed 1198 cells expressing high levels of Wnt5a. This reduced cell survival rate was associated with increased apoptosis via the down-regulation of Bcl2 and the induction of cleaved poly ADP-ribose polymerase. Moreover, CSC-treated 1799 cells showed induction of Wnt5a expression and enhanced colony-forming capacity. The CSC-induced colony forming efficiency was suppressed by the co-incubation with a PKC inhibitor. In conclusion, these results suggest that cigarette smoke induces Wnt5a-coupled PKC activity during lung carcinogenesis, which causes Akt activity and anti-apoptosis in lung cancer. Therefore, current study provides novel clues for the crucial role of Wnt5a in the smoking-related lung carcinogenesis.

Association study of genetic variations in microRNAs with the risk of hepatitis B-related liver diseases.

BACKGROUND AND AIMS: MicroRNAs have been recently identified as important regulators that influence human carcinogenesis, cancer progression, and the interaction between the host and virus. This study investigates an association between microRNAs (miR-101-1, miR-101-2, and miR-338) and the risk of liver diseases through clearance of hepatitis B virus infection, development of liver cirrhosis, and hepatocellular carcinoma occurrence. METHODS: Genetic variations were genotyped using the TaqMan assay in 1439 Korean hepatitis B virus patients. To investigate the relationship between four polymorphisms in three microRNAs and the disease phenotypes, differences in frequency distribution of variations were analysed using logistic and multiple regression analyses after adjusting for age and gender as covariates. RESULTS: We find that the rs7536540 polymorphism in miR-101-1 is significantly associated with development of liver cirrhosis and hepatocellular carcinoma occurrence. In addition, rs12375841 and its unique haplotype (ht2) in miR-101-2 show significant association with clearance of hepatitis B virus infection. CONCLUSIONS: To our knowledge, this is the first study to examine a relationship between the three microRNA genes and the risk of hepatitis B-related liver diseases. We expect that the findings in this study will be helpful to further genetic studies in the pathophysiology of hepatitis B virus-related liver diseases.

Association analysis of C6 genetic variations and aspirin hypersensitivity in Korean asthmatic patients.

There has been increasing evidence that genetic mechanisms contribute to the development of aspirin-intolerant asthma (AIA), a life-threatening disease. The complement component (C6) is a constituent of a biochemical cascade that has been implicated in airway epithelial damage and nasal polyposis, and therefore, may be a risk factor for AIA. To investigate the association between C6 variations and AIA in a Korean asthma cohort, 27 SNPs were selected for genotyping based on previously reported polymorphisms in the HapMap database. Genotyping was carried out using TaqMan assay, and five major haplotypes were obtained in 163 AIA cases and 429 aspirin-tolerant asthma (ATA) controls subjects. Genotype frequency distributions of C6 polymorphisms and haplotypes were analyzed using logistic and regression models. Subsequent analyses revealed a lack of association between C6 genetic variations and AIA. From the initial analyses, marginal associations of rs10512766 (p = 0.04 in co-dominant model) and rs4957374 (p = 0.05 in dominant model) with AIA did not reach the threshold of significance after multiple testing corrections; thus this study failed to find convincing evidence that variations in C6 gene influence the risk of AIA in a Korean population. However, these preliminary results may contribute to the etiology of aspirin hypersensitivity in Korean asthmatic patients.

Association analysis of DTD1 gene variations with aspirin-intolerance in asthmatics.

Aspirin ingestion is a common precipitating factor of life-threatening asthma attacks, requiring some patients to undergo mechanical ventilation. The gene, D-tyrosyl-tRNA deacylase 1 (DTD1), may be a risk factor for aspirin-intolerant asthma (AIA) by catalyzing the hydrolysis of D-tryptophan and interacting with the tyrosyl-tRNA synthetase (tyrRS) enzyme, which promotes a pro-inflammatory phenotype. In order to investigate the association of DTD1 variants with the risk of AIA in an asthma cohort, 38 single nucleotide polymorphisms (SNPs) were genotyped and 5 major haplotypes were obtained in 163 AIA cases and 429 aspirin-tolerant asthma (ATA) controls. Differences in DTD1 SNP and haplotype distributions were analyzed using logistic and multiple regression models and were adjusted for age, gender, smoking status, atopy and body mass index (BMI) as covariates. Subsequent analyses revealed no association between DTD1 variants and the risk of AIA. Although nominal evidence of an association was detected between several DTD1 variants and the rate of decline of the forced expiratory volume in the first second (FEV1) in AIA patients (rs6136444, rs6136469, rs6081338 and DTD1_ht5; P=0.01-0.02), the signals reached the threshold of multiple testing corrections, suggesting that DTD1 variants do not affect the abnormalities of the upper airways in AIA patients.

Lack of association of the RTN4R genetic variations with risk of schizophrenia and SPEM abnormality in a Korean population.

This study examined the association of the reticulon 4 receptor (RTN4R) gene with schizophrenia and smooth pursuit eye movement (SPEM) abnormality in a Korean population. Although we failed to provide convincing evidence that RTN4R is associated with schizophrenia development and SPEM impairment, our findings may be useful for further genetic studies.

Genetic analysis of complement component 9 (C9) polymorphisms with clearance of hepatitis B virus infection.

BACKGROUND: The complement component 9 (C9), a major cytolytic protein in the complement system, plays an important role in the immunological process. However, associations between genetic variations of the complement factor and chronic hepatitis B virus infection still need to be investigated. AIMS: We hypothesized that genetic variations in the complement component 9 gene can influence the clearance of chronic hepatitis B virus infection, hepatocellular carcinoma occurrence, and onset age of hepatocellular carcinoma. To investigate the relationship between complement component 9 variations and these disease phenotypes, we performed a case-control association analysis in a Korean population. METHODS: Genetic variations were identified through direct DNA sequencing and genotyped using TaqMan assay (n = 1,103). In order to investigate the relationship of complement component 9 with chronic hepatitis B virus clearance and hepatocellular carcinoma occurrence, differences in SNP and haplotype frequency distributions were analyzed using logistic and multiple regression analyses with adjusted age and gender as covariates. RESULTS: Although +23189C>T polymorphism in exon 4 and C9_ht2 [T-G-C-A-C] were significantly associated with clearance of chronic hepatitis B virus infection and hepatocellular carcinoma occurrence, the association signals were not retained after multiple testing corrections. CONCLUSIONS: We conclude that variations in the complement component 9 gene are unlikely to influence clearance of chronic hepatitis B virus infection and hepatocellular carcinoma occurrence. Although this preliminary result provides meaningful information, further functional investigations in other genetic factors for pathway analyses are required.

Possible association of SLC22A2 polymorphisms with aspirin-intolerant asthma.

BACKGROUND: Aspirin-intolerant asthma (AIA) is a clinical syndrome characterized by acute bronchoconstriction following the ingestion of aspirin. Solute carrier family 22, member 2 (SLC22A2), also known as organic cation transporter 2 (OCT2), is predominantly expressed in the luminal membrane of airway epithelial cells and has been shown to mediate the transport of prostaglandins on the cyclooxygenase pathway which is regulated by aspirin blockage. Recently, SLC22A2-mediated uptake inhibition by several nonsteroidal anti-inflammatory drugs and decreased SLC22A2 transport activity by its genetic variants have been elucidated in asthma. METHODS: To investigate the associations between AIA and genetic polymorphisms of the SLC22A2 gene, 18 variants were genotyped in 163 AIA subjects and 429 aspirin-tolerant asthma (ATA) controls. Logistic analyses were used to evaluate p values for the associations of SLC22A2 polymorphisms with AIA. RESULTS: One common polymorphism in intron 5, i.e. rs316021, was significantly associated with susceptibility to AIA (p = 0.004, P(corr) = 0.05, OR = 0.60, 95% CI = 0.43-0.85 in a codominant model). The minor allele frequency of rs316021 in the AIA group was significantly lower than that in the ATA controls. In addition, a polymorphism in intron 4 (rs3912161) and a haplotype (SLC22A2-ht3) showed significantly stronger association signals with the FEV(1) fall rate induced by aspirin provocation in AIA subjects compared with ATA controls (p = 0.004, P(corr) = 0.05). CONCLUSION: Our findings suggest that SLC22A2 could be a susceptibility gene for aspirin intolerance in asthmatics.

A possible association of EMID2 polymorphisms with aspirin hypersensitivity in asthma.

Aspirin-intolerant asthma (AIA) is an asthma phenotype characterized by the development of bronchoconstriction following ingestion of aspirin. Despite the well-defined pathological trigger, the underlying mechanisms of AIA are still unclear. With the biophysical characteristics of the human EMI domain-containing protein 2 (EMID2) gene in relation to the extracellular matrix deposition and epithelial-mesenchymal transition as pivotal characteristics of airway remodeling in asthma, we hypothesized that genetic polymorphisms of EMID2 might affect the development of AIA. In this study, the allelic associations of 49 single-nucleotide polymorphisms (SNPs) of the human EMID2 gene were evaluated from 163 AIA patients and 429 aspirin-tolerant asthma (ATA) subjects as controls in a Korean population. Logistic analysis showed that five SNPs (P = 0.01-0.04, but P (corr) > 0.05) and EMID2_BL2_ht2 haplotype (unique to the minor alleles of rs4727494 and rs13233066; P = 0.02; P (corr) = 0.02) were significantly associated with AIA. More interestingly, regression analysis of the decline of forced expiratory volume in one second (FEV(1)) by aspirin provocation revealed that 10 SNPs (P = 0.003-0.04) and four relevant haplotypes (P = 0.002-0.02) were significantly associated with the fall rate of FEV(1) by aspirin provocation, indicating that genetic polymorphisms of EMID2 could cause meaningful deficits in the upper and lower airways among AIA patients. These findings provide evidence that EMID2 may be a susceptible genetic factor for aspirin hypersensitivity among asthmatics in Korean population.

Single-nucleotide polymorphisms (SNPs) and haplotype analysis in vascular endothelial growth factor (VEGF) gene in the patients with Parkinson disease and lung cancer.

The epidemiologic data on smoking in association with Parkinson disease (PD) is puzzling. A lower incidence of smoking-related malignancies, especially lung cancer, has been reported by several studies in the patients with PD. In this study, we investigated polymorphic variations in the vascular endothelial growth factor (VEGF) gene, which has been proposed having a pivotal role in progressive damage of nigral dopaminergic neurons, between Korean patients with 188 PD and 321 lung cancer patients. There were no significant differences in the tested single-nucleotide polymorphisms (SNPs) between patients with PD and lung cancer; however, one haplotype was significantly different in comparisons between the two diseases. These results suggest that VEGF genetic polymorphisms might help understand the low incidence of lung cancer in the patients with PD.

The association of PBX1 polymorphisms with overweight/obesity and metabolic alterations in the Korean population.

Pre-B-cell leukemia transcription factor 1 (PBX1), which is located on chromosome 1q23, was recently reported to be associated with type 2 diabetes mellitus. We examined whether single nucleotide polymorphisms (SNPs) of the PBX1 gene are associated with overweight/obesity in a Korean population. We genotyped 66 SNPs in the PBX1 gene and investigated their association with clinical phenotypes found in 214 overweight/obese subjects and 160 control subjects using the Affymetrix Targeted Genotyping chip array. Seven SNPs (g.+75186C>T, g.+78350C>A, g.+80646C>T, g.+138004C>T, g.+185219G>A, g.+191272A>C, and g.+265317T>A) were associated with the risk of obesity in three models (codominant, dominant, and recessive) (P=0.007-0.05). Haplotype 1 (CAC) and 3 (TAC) of block 3 and haplotype 2 (GGAAT) of block 10 were also strongly associated with the risk of obesity. In the control group, subjects that had homozygote for the major allele for both g.+185219G>A and g.+191272A>C showed lower high density lipoprotein-cholesterol (HDL-C) level compared to those possessing the minor allele, suggesting that the association between the homozygote for the major allele for both g.+185219G>A and g.+191272A>C and HDL-C is attributable to the increased risk of obesity. This study suggests that the PBX1 gene is a possible risk factor in overweight/obese patients.

Assessment of Relationship between Fyn-related Kinase Gene Polymorphisms and Overweight/Obesity in Korean Population.

The fyn-related kinase (FRK) belongs to the tyrosine kinase family of protein kinases. Recent studies have shown that Frk affects pancreatic beta cell number during embryogenesis and promotes beta cell cytotoxic signals in response to streptozotocin. To investigate the genetic association between FRK polymorphisms and the risk of obesity in Korean population, single nucleotide polymorphisms (SNPs) in the FRK gene region were selected and analyzed. The body mass index (BMI) was calculated, and biochemical data (systolic blood pressure, diastolic blood pressure, hemoglobin A1C, triglyceride, total cholesterol, high density lipoprotein, and low density lipoprotein) of blood sample from each subject were also measured. One hundred fifty five healthy control and 204 overweight/obesity subjects were recruited. Genotype frequencies of six SNPs [rs6568920 (+8391G>A), rs3756772 (+56780A>G), rs3798234 (+75687C>T), rs9384970 (+68506G>A), rs1933739 (+72978G>A), and rs9400883 (+75809A>G)] in the FRK gene were determined by Affymetrix Targeted Genotyping Chip data. According to the classification of Korean Society for the Study of Obesity, control (BMI 18 to <23) and overweight/obesity (BMI>/=23) subjects were recruited. For the analysis of genetic data, EM algorithm, SNPStats, Haploview, HapAnalyzer, SNPAnalyzer, and Helixtree programs were used. Multiple logistic regression analysis (codominant, dominant, and recessive models) was performed. Age and gender as covariates were adjusted. For biochemical data, Student's t test was used. The mean value of BMI in the control and overweigh/obesity groups was 21.1+/-1.2 (mean+/-SD) and 25.6+/-2.0, respectively. All biochemical data of the overweight/obesity group were statistically significance, compared with the control group. Among six SNPs, two linkage disequilibrium (LD) blocks were discovered. One block consisted of rs1933739 and rs9400883, and the other comprised rs3756772 and rs3798234. One SNP (rs9384970, +68506G>A) showed an association with overweight/obesity in the codominant model (p=0.03). Interestingly, the AA genotype distribution in the overweight/obesity group (n=7, 3.5%) was higher than those in the control group (n=1, 0.6%), which is not found in either Japanese or Chinese subjects. Therefore, the AA genotype of rs9384970 may be a risk factor for development of obesity in Korean population. The results suggest that FRK may be associated with overweight/obesity in Korean population.