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Leptin plays an important role in regulating adipose-tissue mass. Leptin controls energy balance and food intake through the leptin receptor in the hypothalamus of the brain, which suggests that some polymorphisms of the leptin receptor gene (LEPR) might contribute to obesity or obesity-related diseases. In an effort to identify genetic polymorphisms in a potential candidate gene for obesity and type 2 diabetes mellitus (T2DM) in the Korean population, we have sequenced the LEPR gene. Thirty-five sequence variants were identified (including 9 novel polymorphisms): 1 single nucleotide polymorphism (SNP) in the promoter region, 1 SNP in the 5' UTR, 8 SNPs in exons (3 non-synonymous SNPs), 23 SNPs in introns, 1 ins/del in the 3' UTR, and 1 SNP in the 3' downstream region. To investigate possible association of LEPR polymorphisms with body mass index (BMI) and the risk of T2DM, we genotyped for 11 polymorphisms in the Korean population (n = 1,463). Using statistical analyses, no significant associations between the genetic polymorphisms in the LEPR gene and the risk of T2DM were detected. However, one non-synonymous SNP in exon 3, +5193G > A (Arg109Lys), showed marginal association with BMI (P = 0.02) and gene dose-dependent genetic effects were observed. The present study provides information about additional genetic polymorphisms in LEPR and positive associations of those polymorphisms with BMI in the Korean population.

Although the prevalence of insomnia and the association of insomnia with menopause have been well reported, not much work has been conducted in population-based research on insomnia and menopause in Korea. The purpose of the present report was to determine overall and different prevalence of insomnia by menopausal status, and the relationship between insomnia and menopause in a population-based sample of middle-aged Korean women. A total of 96.1% of 2497 randomly selected middle-aged Korean women participated. Insomnia was defined as occurring three times a week or more in the previous month. Subjects were categorized into three groups: premenopaues, perimenopause, and postmenopause. The overall prevalence of insomnia in middle-aged Korean women was 14.3%. The most common symptom of insomnia was difficulty maintaining sleep (9.7%), followed by difficulty initiating sleep (7.9%), and early morning awakening (7.5%). Multiple logistic regression analysis revealed that menopause was independently associated with insomnia after adjusting for confounding factors such as age, income, and depression. Perimenopause was significantly associated with a dramatic increase in the risk of insomnia, but there was no significant association for postmenopause. The major finding is that insomnia is significantly associated with the menopausal transition. The prevalence of insomnia increases significantly by the transition from premenopause to perimenopause, but not to postmenopause. A further prospective study is needed to investigate the influence of menopause on insomnia.

Understanding patterns of linkage disequilibrium (LD) across genomes may facilitate association mapping studies to localize genetic variants influencing complex diseases, a recognition that led to the International Haplotype Mapping Project (HapMap). Divergent patterns of haplotype frequency and LD across global populations require that the HapMap database be supplemented with haplotype and LD data from additional populations. We conducted a pilot study of the LD and haplotype structure of a genomic region in a Korean population. A total of 165 SNPs were identified in a 200-kb region of 22q13.2 by direct sequencing. Unphased genotype data were generated for 76 SNPs in 90 unrelated Korean individuals. LD, haplotype diversity, and recombination rates were assessed in this region and compared with the HapMap database. The pattern of LD and haplotype frequencies of Korean samples showed a high degree of similarity with Japanese data. There was a strong correlation between high LD and low recombination frequency in this region. We found considerable similarities in local LD patterns between three Asian populations (Han Chinese, Japanese, and Korean) and the CEPH population. Haplotype frequencies were, however, significantly different between them. Our results should further the understanding of distinctive Korean genomic features and assist in designing appropriate association studies.

The present study was purposed to identify the prevalence of restless legs syndrome (RLS) and its associated factors in the Korean adult population. Among a total of 9939 participants derived from the Korean Health and Genome Study, 12.1% of subjects (men, 8.5%; women, 15.4%) suffered from RLS. Factors independently related with RLS were older age and frequent fatigue in both men and women.

Asthma is a chronic inflammatory disorder of the airways, and a number of genetic loci are associated with the disease. Candidate gene association studies have been regarded as effective tools to study complex traits. Knowledge of the sequence variation and structure of the candidate genes is required for association studies. Thus, we investigated the genetic variants of 32 asthma candidate genes selected by colocalization of positional and functional candidate genes. We screened all exons and promoter regions of those genes using 12 healthy individuals and 12 asthma patients and identified a total of 418 single nucleotide polymorphisms (SNPs), including 270 known SNPs and 148 novel SNPs. Levels of nucleotide diversity varied from gene to gene (0.72 x 10(-4)-14.53 x 10(-4)), but the average nucleotide diversity between coding SNPs (cSNPs) and noncoding SNPs was roughly equivalent (4.63 x 10(-4) vs 4.69 x 10(-4)). However, nucleotide diversity of cSNPs was strongly correlated to codon degeneracy. Nucleotide diversity was much higher at fourfold degenerate sites than at nondegenerate sites (9.42 x 10(-4) vs 3.14 x 10(-4)). Gene-based haplotype analysis of asthma-associated genes in this study revealed that common haplotypes (frequency5%) represented 90.5% of chromosomes, and they could be uniquely identified with five or fewer haplotype-tagging SNPs per gene. Therefore, our results may have important implications for the selection of asthma candidate genes and SNP markers for comprehensive association studies using large sample populations.

Zeocin, a member of the bleomycin/phleomycin family of antibiotics, is known to bind DNA and to induce apoptosis in cervical cancer cells, but the mechanism underlying this apoptotic response is poorly understood. The present study was undertaken to elucidate time-dependent serial transcript patterns in the HeLa cervical carcinoma cell line, following treatment with Zeocin. The HeLa cell proliferation rate was found to gradually decrease following Zeocin exposure, in a time-and dose-dependent manner. RNA transcript level measurements, for time-dependent serial gene expression profiling, were determined at 0, 6, 12, 18 and 24 hr using a 0.5 k apoptosis functional microarray chip. Further statistical analysis, using a significance test at a 95% confidence level, for transcripts with a greater than 2-fold change on the array chips, identified 49 up-regulated and 57 down-regulated genes. Our gene expression profile data indicate that Zeocin treatment induces an initial release of cytochrome c, the down-regulation of Bcl-X (L), ENDOG, DAXX and MDM2, and the up-regulation of CASP and BID. This suggests that a p53-independent mitochondrial caspase cascade pathway is primarily involved in Zeocin-induced apoptosis. Such caspasedependent cytotoxic activity also implies that this cell death pathway occurs via the caspase 8 and BID genes. However, disruption of either FAS or TNFR1 signaling did not interfere with the Zeocin induced apoptotic response in our experimental system. We hypothesize that Zeocin could be active against cervical cancer cell resistance to conventional chemotherapy and postulate that Zeocin is a novel candidate for the development of new chemotherapeutic treatments of gynecological cancers.

In an effort to identify genetic polymorphisms in potential candidate genes for type 2 diabetes mellitus (T2DM), we have sequenced the transforming growth factor beta-induced gene (TGFBI), and examined the association with T2DM and diabetic phenotypes in a Korean T2DM study (775 T2DM patients and 316 normal controls). Twenty-eight polymorphisms were identified in TGFBI. Although no significant associations were detected with the risk of T2DM, one SNP in intron 16 (c.2011+137C>T) and one SNP in the 3' untranslated region (UTR) (c.2589T>G), showed significant association with the levels of insulin and body mass index (BMI) among nondiabetic controls. The lower insulin and BMI were observed in individuals who carry one or two copies of minor alleles than others. For example, the highest BMI (24.21 kg/m(2)) in individuals with homozygote major alleles (T) of c.2589T>G (n=99), the intermediate BMI (23.68 kg/m(2)) in individuals with heterozygote alleles (n=156), and the lowest BMI (22.69 kg/m(2)) in individuals with homozygote minor alleles (G) (n=57, P=0.005) were observed. The present study provides, for the first time, information about genetic polymorphisms in TGFBI and positive associations of those polymorphisms with levels of insulin and BMI in the Korean population.

The prevalence of undiagnosed airflow obstruction is difficult to measure since it requires screening in population-based samples to identify individuals free of clinical symptoms. The purpose of this report is to examine the prevalence of undiagnosed airflow obstruction and its relation with respiratory symptoms in middle-age adults in the Korean Health and Genome (KHG) Study.The KHG study is an ongoing population-based study of Korean adults aged 40 to 69 years. The current report includes 8,140 men and women without a pulmonary disorder or obstructive lung disease. In this sample, undiagnosed airflow obstruction was defined on the basis of spirometric testing and in the absence of a medical history or a recognized pulmonary disorder. Respiratory symptoms included chronic cough, chronic phlegm, wheezing, and shortness of breath.Undiagnosed airflow obstruction was observed in 12.4% of the men (470 of 3,806 subjects) and in 3.5% of the women (152 of 4,334 subjects). In men, the age-adjusted prevalence of undiagnosed airflow obstruction increased consistently with increasing number of respiratory symptoms. In those who smoked, there was a 2.3-fold excess in its prevalence when three or more symptoms were present, as compared to when they were absent (27.4% vs 12.0%, p0.001). A 2.4-fold excess (20.6% vs 8.5%, p = 0.004) was observed in nonsmoking men, in whom respiratory symptoms were consistently less common than in those who smoked. Respiratory symptoms were unrelated to undiagnosed airflow obstruction in women smokers, although only 3.9% smoked cigarettes. In women who were nonsmokers, the prevalence of undiagnosed airflow obstruction increased from 2.3% in those without a respiratory symptom to 6.0% when three or more symptoms were present (p = 0.003).Findings suggest that undiagnosed airflow obstruction is common in Korea with several respiratory symptoms. Whether respiratory symptoms with associations with undiagnosed airflow obstruction can be used to design early intervention strategies that prevent or delay the onset of COPD and its disabling consequences warrants further study.

Motivation: Phosphorylation is involved in diverse signal transduction pathways. By predicting phosphorylation sites and their kinases from primary protein sequences, we can obtain much valuable information that can form the basis for further research. Using support vector machines, we attempted to predict phosphorylation sites and the type of kinase that acts at each site. Results: Our prediction system was limited to phosphorylation sites catalyzed by four protein kinase families and four protein kinase groups. The accuracy of the predictions ranged from 83 to 95% at the kinase family level, and 76–91% at the kinase group level. The prediction system used—PredPhospho—can be applied to the functional study of proteins, and can help predict the changes in phosphorylation sites caused by amino acid variations at intra- and interspecies levels. Availability: PredPhospho is available at http://www.ngri.re.kr/proteo/PredPhospho.htm. Supplementary information: http://www.ngri.re.kr/proteo/supplementary.doc

Competition for cellular iron (Fe) is a vital component of the interaction between host and pathogen. Most bacteria have an obligate requirement for Fe to sustain infection, growth, and survival in host. To obtain iron required for growth, many bacteria secrete iron chelators (siderophores). This study was undertaken to test whether a bacterial siderophore, deferoxamine (DFO), could trigger inflammatory signals in human intestinal epithelial cells as a single stimulus. Incubation of human intestinal epithelial HT-29 cells with DFO increased the expression of IL-8 mRNA, as well as the release of IL-8 protein. The signal transduction study revealed that both p38 and extracellular signal-regulated kinase-1/2 were significantly activated in response to DFO. Accordingly, the selective inhibitors for both kinases, either alone or in combination, completely abolished DFO-induced IL-8 secretion, indicating an importance of mitogen-activated protein kinases pathway. These proinflammatory effects of DFO were, in large part, mediated by activation of Na+/H+ exchangers, because selective blockade of Na+/H+ exchangers prevented the DFO-induced IL-8 production. Interestingly, however, DFO neither induced NF-κB activation by itself nor affected IL-1β- or TNF-α-mediated NF-κB activation, suggesting a NF-κB-independent mechanism in DFO-induced IL-8 production. Global gene expression profiling revealed that DFO significantly up-regulates inflammation-related genes including proinflammatory genes, and that many of those genes are down-modulated by the selective mitogen-activated protein kinase inhibitors. Collectively, these results demonstrate that, in addition to bacterial products or cell wall components, direct chelation of host Fe by infected bacteria may also contribute to the evocation of host inflammatory responses.

To examine the prevalence and correlates of orthostatic hypotension (OH) in middle-aged adults enrolled in the Korean Health and Genome Study. Participants were 8908 individuals aged 40-69 years. Supine blood pressure (BP) was measured three times at 30-s intervals after at least 5 min of rest in the supine position and single standing BP was measured at 0 and 2 min after standing, respectively. OH was defined as a reduction in systolic BP or diastolic BP > or = 20 and 10 mmHg, respectively. The prevalence of OH at 0 and 2 min after standing was 12.3 and 2.9%, respectively. At 0 min of standing, OH frequency increased significantly with age from 6.4% in those aged 40-44 years to 23.1% in those aged 65-69 (P < 0.001). After adjustment for age and other characteristics, hypertension was associated with a 1.7-fold excess in the odds of OH in men and a 1.6-fold excess in women (P < 0.001). In contrast, an increase in body mass index (BMI) on the order of 5 kg/m2 was associated with a 20-30% reduction in the odds of OH (P < 0.001). Diabetes in women was also associated with a 1.4-fold excess in the odds of OH (P < 0.05). An increase in triglyceride by 136 mg/dl in men was associated with an increase in the odds of OH (P < 0.05). In conclusion, the prevalence and correlates of OH other than diabetes and triglycerides were notably similar in men and women. While the association between hypertension and OH has been observed elsewhere, low BMI in Korean adults with OH may be an important marker for subclinical morbidity or coexisting risk factors that need to be identified.

The tumor necrosis factor (TNF) and TNF receptor (TNF-TNFR) superfamily plays crucial roles in immune regulation and host immune responses. The superfamily has been also associated with many immune-mediated diseases such as asthma, rheumatoid arthritis, inflammatory bowel disease, and diabetes. In order to investigate genetic variants of the TNF-TNFR superfamily, a total of 63 known single nucleotide polymorphisms (SNPs) in the coding region (cSNPs) of the TNF-TNFR superfamily genes were selected from the public SNP database. Among 63 cSNPs tested in this study, only 24 SNPs (38%) were validated to be polymorphic in the Korean population by primer extension-based SNP genotyping. By means of the new enhanced single strand conformational polymorphism (SSCP) method, we also identified a total of 78 SNPs, including 48 known SNPs and 30 novel SNPs, in the 44 human TNF-TNFR superfamily genes. The newly discovered SNPs in the TNF-TNFR superfamily genes revealed that the Korean population had very different patterns of allele frequency compared with African or white populations, whereas Korean allele frequencies were highly similar to those of Asian (correlation coefficient r = 0.88, p < 0.046). A higher similarity of allele frequency was observed between Korean and Japanese populations (r = 0.90, p < 0.001). The validated SNPs in the TNF-TNFR superfamily would be valuable for association studies with several immune-mediated human diseases.

In postgenomic era, searching and identification of disease genes associated with complex diseases are still one of the great challenge for dissecting human complex diseases. To improve the disease gene localization for complex diseases, a group of closely immune-mediated disease loci were overlapped on each chromosome based on previously reported genome-wide scanning data. Interestingly, five overlapping chromosomal regions (1q21, 2q33, 5q31.1-q33.1, 6p21, and 11q13) were identified by co-localizing disease loci for the following diseases: diabetes, asthma, atopic dermatitis, osteoporosis, and inflammatory bowel disease. The development of specific disease was associated with different combinations of disease loci among five overlapped chromosomal regions. Therefore, the analysis of multiple genetic loci should be considered to determine the effects of multiple genes responsible for complex diseases resulting from the influence of multiple genes.

The incidence of type 2 diabetes is rising rapidly because of an increase in the incidence of being overweight and obesity. Identification of genetic determinants for complex diseases, such as type 2 diabetes, may provide insight into disease pathogenesis. The aim of the study was to investigate the shared genetic factors that predispose individuals to being overweight and developing type 2 diabetes. We conducted genome-wide linkage analyses for type 2 diabetes in 386 affected individuals (269 sibpairs) from 171 Korean families and association analyses with single-nucleotide polymorphisms of candidate genes within linkage regions to identify genetic variants that predispose individuals to being overweight and developing type 2 diabetes. Through fine-mapping analysis of chromosome 4q34-35, we detected a locus potentially linked (nonparametric linkage 2.81, logarithm of odds 2.27, P=6×10(-4)) to type 2 diabetes in overweight or obese individuals (body mass index, BMI≥23 kg m(-2)). Multiple regression analysis with type 2 diabetes-related phenotypes revealed a significant association (false discovery rate (FDR) P=0.006 for rs13144140; FDR P=0.002 for rs6830266) between GPM6A (rs13144140) and BMI and waist-hip ratio, and between NEIL3 (rs6830266) and insulin level from 1314 normal individuals. Our systematic search of genome-wide linkage and association studies, demonstrate that a linkage peak for type 2 diabetes on chromosome 4q34-35 contains two type 2 diabetes-related genes, GPM6A and NEIL3.

Background The Reg gene has been reported to be expressed in regenerating islets and Reg1 protein to be up-regulated at an early stage of diabetes in mice. As human Reg1α is homologous with murine Reg1, we investigated whether common variants in Reg1α are associated with type 2 diabetes in the Korean population. Methods We sequenced the Reg1α gene to identify common polymorphisms using 24 Korean DNA samples. Of 11 polymorphisms found, five common ones (g.-385T>C [rs10165462], g.-36T>G [rs25689789], g.209G>T [rs2070707], g.1385C>G [novel], and g.2199G>A [novel]) were genotyped in 752 type 2 diabetic patients and 642 non-diabetic subjects. Results No polymorphism was associated with the risk of type 2 diabetes. However, g.-385C and g.2199A lowered the risk of early-onset type 2 diabetes, defined as a diagnosis in subjects whose age at diagnosis was 25 years or more but less than 40 years (odds ratio [OR], 0.721 [0.535 to 0.971] and 0.731 [0.546 to 0.977] for g.-385C and g.2199A, respectively) and g.1385G increased the risk of early-onset diabetes (OR, 1.398 [1.055 to 1.854]). Although adjusting for errors in multiple hypotheses-testing showed no statistically significant association between the three individual polymorphisms and early-onset diabetes, the haplotype H1, composed of g.-385C, g.1385C, and g.2199A, was associated with a reduced risk of early-onset diabetes (OR, 0.590 [0.396 to 0.877], P = 0.009). Conclusion Polymorphisms in the Reg1α were not found to be associated with overall susceptibility to type 2 diabetes, though some showed modest associations with early-onset type 2 diabetes in the Korean population.

Background CXCR3 is a chemokine receptor that plays important roles in mediating chemotactic signals and modulating the activation of lymphocytes. We have previously conducted a case-control study by using a candidate gene approach to investigate the association of CXCR3 polymorphisms with the risk of asthma. Results from the epidemiologic study showed that a common nucleotide variant in the CXCR3 intron (rs2280964G>A) was associated with disease susceptibility (1006 cases and 384 control subjects; odds ratio, 0.81; 95% CI, 0.69-0.94; P = .007). Objective The aim of our study was to evaluate the epidemiologic study and provide functional evidence for the association of rs2280964G>A with asthma by investigating the effects of intronic variant on chemokine-mediated phenotypes of human-derived T cells. Methods We used cell line–based in vitro and human primary T cell–based ex vivo studies to examine the functional consequences of the intronic polymorphism, focusing on the regulation of gene expression, splicing, and immune responsiveness toward activating signals. Results We present functional evidence indicating that the rs2280964A allele significantly correlates with decreased CXCR3 gene expression, which would lead to variation in immune cell responses to chemokine-cytokine signals in vitro and ex vivo that includes a decrease in chemotactic activity. Conclusion These findings, in conjunction with those of our previous epidemiologic studies, might implicate a functional link between a common nucleotide variant of a chemokine receptor gene, CXCR3 , and a cause for a complex-trait disease, asthma.

Purpose Hepatic stellate cells (HSC) are a type of pericyte with varying characteristics according to their location. However, the electrophysiological properties of HSC are not completely understood. Therefore, this study investigated the difference in the voltage-dependent K(+) currents in HSC. Materials and methods The voltage-dependent K(+) currents in rat HSC were evaluated using the whole cell configuration of the patch-clamp technique. Results Four different types of voltage-dependent K(+) currents in HSC were identified based on the outward and inward K(+) currents. Type D had the dominant delayed rectifier K(+) current, and type A had the dominant transient outward K(+) current. Type I had an inwardly rectifying K(+) current, whereas the non-type I did not. TEA (5 mM) and 4-AP (2 mM) suppressed the outward K(+) currents differentially in type D and A. Changing the holding potential from -80 to -40 mV reduced the amplitude of the transient outward K(+) currents in type A. The inwardly rectifying K(+) currents either declined markedly or were sustained in type I during the hyperpolarizing step pulses from -120 to -150 mV. Conclusion There are four different configurations of voltage-dependent K(+) currents expressed in cultured HSC. These results are expected to provide information that will help determine the properties of the K(+) currents in HSC as well as the different type HSC populations.

Increased expression of glucose transporter1 (GLUT1) has been reported in many human cancers. We hypothesized that the degree of GLUT1 might provide a useful biological information in gastric adenocarcinoma. RT-PCR and immunostaining were used to analyze GLUT1 expression in gastric cancer. RT-PCR showed GLUT1 expression was not largely detected in normal gastric tissue but was detected in cancerous gastric tissue of counterpart. By immunohistochemistry, GLUT1 protein was absent in normal gastric epithelium and intestinal metaplasia. 11 of 65 patients with gastric adenocarcinoma had specific GLUT1 immunostaining in a plasma membrane pattern with varied intensities. GLUT1 protein did not show any significant correlation with tumor stage and nodal metastasis (p>0.05 by Mann-Whitney test). However, the positive immunostaining for GLUT1 is associated with intestinal differentiation (p=0.003). Our results suggest that GLUT1 protein is associated with intestinal type of gastric cancer.