Haplotype variation at the IBD5/SLC22A4 locus (5q31) in coeliac disease in the Irish population

In addition to the well-established association of coeliac disease (CD) with HLA-DQ (6p21) and possibly CTLA4 (2q33), there is considerable evidence for a susceptibility locus on chromosome 5q, which contains many potential candidates for inflammatory disease, including a cluster of cytokine genes in 5q31. CD cases and controls were genotyped for four single-nucleotide polymorphism (SNP) markers that together characterize >90% of the haplotype variation at the IBD5 locus encoding, among others, the SLC22A4 gene. IBD5 and SLC22A4 map to 5q31 and have recently been associated with Crohn's disease and rheumatoid arthritis. Haplotype frequencies do not differ significantly between CD cases and controls in the Irish population, and therefore the chromosome 5 CD susceptibility locus most likely lies elsewhere on 5q.     

Association of the organic cation transporter OCTN genes with Crohn's disease in the Spanish population

The SLC22A4 and SLC22A5 genes within the IBD5 risk locus encode the organic cation transporters OCTN1 and OCTN2. Two variants, 1672C>T in SLC22A4 and -207G>C in SLC22A5, were shown to alter these genes' functions and were identified as genetic susceptibility factors for Crohn's disease (CD). We pursued to check both putative etiologic variants in an independent population through a case-control study with 309 Spanish CD patients and 408 ethnically matched healthy subjects. Both polymorphisms were found in partial linkage disequilibrium (D'=0.86). The separate analysis of each OCTN variant evidenced no association. However, when the simultaneous presence of mutant variants in both genes was analyzed, an effect on CD susceptibility was observed (P=0.026, odds ratio (OR) (95% confidence interval (CI))=1.59 (1.03-2.45)). The previously described predisposition conferred by the 5q31-risk haplotype increased in the absence of the etiologic 1672T and -207C alleles (P=0.0006, OR (95% CI)=10.14 (1.97-98.04)). Moreover, the risk contributed by these polymorphisms was higher in the IBD5 wild-type population (P=0.003, OR (95% CI)=2.65 (1.32-5.35)), arguing against the exclusive etiological role of the OCTN variants. The haplotype pattern inferred led to the consideration of these variants as susceptibility markers only in a defined genetic context. Our data support the interpretation of the 1672C>T SLC22A4 and -207G>C SLC22A5 polymorphisms as genetic markers of susceptibility/protection haplotypes.     

Sequence variation, linkage disequilibrium and association with Crohn's disease on chromosome 5q31

Chromosome 5q31 contains a cluster of genes involved in immune response, including a 250 kb risk haplotype associated with Crohn's disease (CD) susceptibility. Recently, two functional variants in SLC22A4 and SLC22A5 (L503F and G-207C), encoding the cation transporters OCTN1 and OCTN2, were proposed as causal variants for CD, but with conflicting genetic evidence regarding their contribution. We investigated this locus by resequencing the coding regions of 10 genes in 24 CD cases and deriving a linkage disequilibrium (LD) map of the 27 single nucleotide polymorphisms (SNPs) detected. Ten SNPs representative of the LD groups observed, were tested for CD association. L503F in SLC22A4 was the only nonsynonymous SNP significantly associated with CD (P=0.003), but was not associated with disease in the absence of other markers of the 250 kb risk haplotype. Two other SNPs, rs11242115 in IRF1 and rs17166050 in RAD50, lying outside the 250 kb risk haplotype, also showed CD association (P=0.019 and P=0.0080, respectively). The RAD50 gene contains a locus control region regulating expression of the Th2 cytokine genes at this locus. Other as yet undiscovered SNPs in this region may therefore modulate gene expression and contribute to the risk of CD, and perhaps of other inflammatory phenotypes.     

Association analysis of <Emphasis Type="Italic">SLC22A4</Emphasis>, <Emphasis Type="Italic">SLC22A5</Emphasis> and <Emphasis Type="Italic">DLG5</Emphasis> in Japanese patients with Crohn disease

Crohn disease (CD) is an inflammatory bowel disease characterized by chronic transmural, segmental, and typically granulomatous inflammation of the gut. Recently, two novel candidate gene loci associated with CD, SLC22A4 and SLC22A5 on chromosome 5 known as IBD5 and DLG5 on chromosome 10, were identified through association analysis of Caucasian CD patients. We validated these candidate genes in Japanese patients with CD and found a weak but possible association with both SLC22A4 (P=0.028) and DLG5 (P=0.023). However, the reported genetic variants that were indicated to be causative in the Caucasian population were completely absent in or were not associated with Japanese CD patients. These findings imply significant differences in genetic background with CD susceptibility among different ethnic groups and further indicate some difficulty of population-based studies.     

DLG5 variants contribute to Crohn disease risk in a Canadian population

Variants in the gene encoding the DLG5 scaffolding protein have been reported to be associated with increased risk of inflammatory bowel disease (IBD) and particularly Crohn's disease (Crohn disease; CD). These findings have not been uniformly replicated in follow-up studies. In this study we genotyped a cohort of 402 Canadian CD and 179 ulcerative colitis (UC) patients and 537 healthy controls for three IBD/CD-associated DLG5 variants. Our data reveal that the common DLG5 haplotype (A), which was previously considered protective for IBD, is associated with modest increases in risk for IBD (P=0.02) and CD (P=0.04). The effects of haplotype copy number on risk for IBD were minor, with the odds ratio (ORs) being 1.37 for the heterozygous risk genotype and 1.7 for the homozygous risk genotype. While we were unable to replicate the proposed association between the DLG5 c.113G>A variant and IBD, an association of IBD (P=0.02) and CD (P=0.04) with the rarer c.4136C>A variant was replicated in this cohort. These associations were restricted to the non-Jewish subjects in this cohort and were not detected in the Ashkenazi Jewish population studied here. Within the non-Jewish group, no associations were detected between the DLG5 variants and specific phenotypic features, such as site of disease, and there was no evidence of epistasis between DLG5 and any of the CD-associated CARD15 or SLC22A4/A5 gene variants. Together, the results indicate a role for DLG5 variants in IBD susceptibility and suggest that further studies are warranted to evaluate this role in different IBD populations and to determine the functional pathways that couple DLG5 variants to IBD.     

应用染色质免疫沉淀技术分析DNMT3b和HDAC1蛋白与SLC22A18基因启动子的结合

目的 建立优化的染色质免疫沉淀技术(ChIP),分析乳腺癌细胞MDA-MB-231中DNA甲基转移酶3b(Dnmt3b)和组蛋白去乙酰化酶1(HDAC1)与SLC22A18基因启动子区的结合情况. 方法 建立并优化ChIP实验技术,运用ChIP技术检测DNA甲基转移酶抑制剂5-氮杂-2′-脱氧胞苷(5-aza-dc)和组蛋白去乙酰化酶抑制剂曲古霉素A(TSA)分别单独和联合作用于人乳腺癌细胞MDA-MB-231后,用Dnmt3b和HDAC1特异性抗体沉淀DNA,聚合酶链式反应(PCR)检测SLC22A18基因5＇端特异性序列,免疫印迹法(Western blotting)检测Dnmt3b和HDAC1蛋白的表达情况. 结果 获得了优化的ChIP实验条件,Dnmt3b和HDAC1抗体沉淀的染色质片段中扩增出SLC22A18基因5＇端特异性序列.5-aza-dc、TSA单独用药可抑制DNMT3b、HDAC1与SLC22A18启动子区特异序列的结合,5-aza-dc和TSA联合作用可以明显抑制DNMT3b、HDAC1与SLC22A18启动子的结合;Western blotting结果表明,5-aza-dc、TSA单独及联合用药不影响DNMT3b和HDAC1蛋白的表达. 结论 DNMT3b和HDAC1在MDA-MB-231细胞内结合于SLC22A18基因启动子的特异区域,参与该基因的表达调控.     

Genetic variability of the extraneuronal monoamine transporter EMT (SLC22A3)

The extraneuronal monoamine transporter EMT (HGNC Nomenclature SLC22A3) is the molecular correlate of the classical uptake₂ system responsible for the non-neuronal inactivation of circulating and centrally released catecholamines. Because of its functional profile and expression pattern, EMT is regarded as a candidate gene for diseases related to the sympathetic nervous system and neuropsychiatric disorders. We describe the first investigation of the genetic variability of the EMT gene in human. Six single-nucleotide substitutions and one deletion were detected within the assumed core promoter, the exonic and flanking intronic sequences and the 3'-untranslated region in 100 Caucasian individuals. No amino acid changes were found and Tajima's D was positive (D=2.91; P<0.01). However, the synonymous nucleotide substitution 1233G→A might serve as a cryptic splice acceptor site. Analysis of linkage disequilibrium between polymorphisms yielded 12 possible haplotypes accounting for more than 90% of all haplotypes. Knowledge of the sequence variation and frequency of the underlying polymorphisms in this member of the amphiphilic solute facilitator family of transporters provides the basis for subsequent association studies and candidate gene approaches. Electronic Publication     

Catalog of 238 variations among six human genes encoding solute carriers (hSLCs) in the Japanese population

We screened DNAs of 48 Japanese individuals for single-nucleotide polymorphisms (SNPs) in six genes encoding proteins of the solute carrier (SLC) family by direct sequencing of their entire genomic regions except for repetitive-sequence elements. This approach identified 213 SNPs and 25 insertion/deletion polymorphisms among the six genes. On average, we identified 1 SNP in every 509 nucleotides. Of the 213 SNPs, 14 were identified in the SLC10A1 gene, 51 in SLC15A1, 29 in SLC22A1, 27 in SLC22A2, 54 in SLC22A4, and 38 in SLC22A5. Eight were located in 5′ flanking regions, 172 in introns, 25 in exons, and 8 in 3′ flanking regions. These variants should contribute to investigations of possible correlations between genotypes and phenotypes as regards disease susceptibilities or responsiveness to drug therapy. Received: July 24, 2002 / Accepted: July 25, 2002 Correspondence to:Y. Nakamura     

Age and origin of the G774A mutation in SLC22A12 causing renal hypouricemia in Japanese

Renal hypouricemia is an inherited disorder characterized by impaired tubular uric acid transport. Impairment of the function of URAT1, the main transporter for the reabsorption of uric acid at the apical membrane of the renal tubules, causes renal hypouricemia. The G774A mutation in the SLC22A12 gene encoding URAT1 predominates in Japanese renal hypouricemia. From data on linkage disequilibrium between the G774 locus and the 13 markers flanking it (12 single nucleotide polymorphisms and 1 dinucleotide insertion/deletion locus), we here estimate the age of this mutation at approximately 6820 years [95% confidence interval (CI) 1860–11,760 years; median = 2460 years]. This indicates that the origin of the G774A mutation dates back from between the time when the Jomon people predominated in Japan and the time when the Yayoi people started to migrate to Japan from the Korean peninsula. These data are consistent with a recent finding that this G774A mutation was also predominant in Koreans with hypouricemia and indicate that the mutation originated on the Asian continent. Thus, this mutation found in Japanese patients was originally brought by immigrant(s) from the continent and thereafter expanded in the Japanese population either by founder effects or by genetic drift (or both).     

Haplotype analysis of single nucleotide polymorphisms in VEGF gene for vascular dementia.

A case-control study was performed to identify single nucleotide variants of vascular endothelial growth factor (VEGF) gene associated with vascular dementia. Seven SNPs in promoter, 5'-UTR, 3'-UTR, and introns of VEGF gene were identified in 24 Koreans. Three of them, -1154G/A, -7C/T, and 13553C/T, were selected based on allele frequency and linkage disequilibrium (LD), and genotyped in 207 vascular dementia patients and 207 control subjects. Significant association with vascular dementia was not shown (P > 0.05) in the alleles and genotypes of single locus. Subsequent analysis of composing VEGF risk haplotypes associated with vascular dementia was performed with maximum likelihood estimates of their possible haplotypes employing the expectation-maximization (EM) algorithm. Of three-locus haplotypes, only GTC was significantly associated with vascular dementia, conferring a risk of 1.87 (P < 0.05). Of two-locus haplotypes, the risk was observed with the nested forms of the risk haplotype GTC, that is, GT at the loci -1154G/A and -7C/T and TC at the loci -7C/T and 13553C/T (P < 0.05). Our findings suggested some interaction among -1154G/A, -7C/T, and 13553C/T variants in the determination of risk for vascular dementia.     

乳腺癌中印记基因SLC22A18/TSSC5/BWR1A启动子区甲基化及mRNA表达的研究

目的： 研究印记基因SLC22A18启动子区甲基化对乳腺侵润性导管癌组织中的SLC22A18 mRNA表达的影响，探讨其与临床病理特征之间的关系。方法：实时荧光定量逆转录聚合酶链反应（real-time quantitative RT-PCR）方法检测40例乳腺侵润性导管癌及其癌旁组织中SLC22A18 mRNA的表达，甲基化特异性聚合酶链反应(MSP)检测SLC22A18基因启动子区的甲基化状态。检测DNA甲基转移酶抑制剂5-氮杂-2′-脱氧胞苷（5-aza-2′-deoxycytidine，5-aza-dc）和组蛋白去乙酰化酶抑制剂曲古霉素A（TSA）作用于乳腺癌细胞株MDA-MB-231后，对SLC22A18基因启动子区DNA甲基化和mRNA表达的影响。结果：SLC22A18在40例乳腺侵润性导管癌中mRNA表达量低于癌旁组织（0.12±0.10 vs 0.69±1.05，P＜0.01）；40例乳腺侵润性导管癌及对应癌旁组织中，SLC22A18启动子区的甲基化发生率分别为75％和37.5%，差异有统计学意义（P＜0.01）；在40例乳腺侵润性导管癌组织中，甲基化组SLC22A18 mRNA表达量低于非甲基化组（0.11±0.08 vs 0.24±0.18，P＜0.01）。5-aza-dc和5-aza-dc/TSA能不同程度逆转乳腺癌细胞株MDA-MB-231中SLC22A18基因的甲基化状态，并上调SLC22A18基因表达。结论：SLC22A18基因甲基化与乳腺癌发生有一定的关联，SLC22A18基因表达下调与其启动子区CpG岛异常甲基化相关。     

Association of SLC11A1 (NRAMP1) polymorphisms with pulmonary Mycobacterium avium complex infection

Although genetic variants in SLC11A1 (NRAMP1) have been associated with mycobacterial diseases, these findings have not been extensively validated in pulmonary Mycobacterium avium complex (MAC) infection. This study investigated the genomic structure of SLC11A1 and its association with MAC infection. Nineteen polymorphic loci were genotyped in European descendents and the Japanese population. Linkage disequilibrium (LD) structures and frequencies of major haplotypes differed between these 2 populations. Tag single nucleotide polymorphisms (SNPs) were chosen from the data set, and 6 polymorphic sites were genotyped in 122 pulmonary MAC cases and 211 controls from Japan. We observed that the T allele of rs2279014 in the 3' untranslated region was associated with protection from MAC disease when comparing allele frequencies with an odds ratio of 0.582 (95% confidence interval 0.379-0.894, p = 0.013). The frequencies of haplotypes constructed with the above 6 variants did not differ between cases and controls. Allele-specific expression imbalance of SLC11A1 mRNA was evaluated in peripheral blood cells from heterozygous individuals, but no difference was observed among haplotypes. Although the significance was modest, rs2279014 is in strong LD with nearby SNPs and further studies are required for conclusive validation.     

Novel SLC5A2 Variants Contribute to Renal Glucosuria in Chinese Families: Abnormal Expression and Dysfunction of Variant SLC5A2

Familial renal glucosuria (FRG) is characterized by persistent glucosuria despite normal serum glucose and the absence of overt tubular dysfunction. Variants in solute carrier family 5 (sodium–glucose cotransporter), member 2 (SLC5A2) have been reported in FRG patients. However, the functional and expression‐related consequences of such variants have been scarcely investigated. In the current study, we studied five FRG families and identified six missense mutations, including four novel variants (c.1051T>C/.(C351R), c.1400T>C/p.(V467A), c.1420G>C/p.(A474P), c.1691G>A/p.(R564Q); RNA not analyzed) and two variants that had been previously reported (c.294C>A/p.(F98L), c.736C>T/p.(P246S); RNA not analyzed). The probands were either heterozygous or compound heterozygous for SLC5A2 variants and had glucosuria of 5.9%–19.6 g/day. Human 293 cells were transfected with plasmid constructs to study the expression and function of SLC5A2 variants in vitro. Western blotting revealed that the expression levels of SLC5A2–351R‐GFP, SLC5A2–467A‐GFP, SLC5A2–474P‐GFP, and SLC5A2–564Q‐GFP were significantly decreased compared with wild‐type SLC5A2‐GFP (37%–55%). Confocal microscopy revealed that three variants (c.1400T>C, c.1420G>C, c.1691G>A) resulted in a loss of the punctate membrane pattern typical of wild‐type SLC5A2. All variants had a significantly lower transport capacity in than the wild‐type control. The current study provides a starting point to further investigate the molecular mechanism of SLC5A2 in FRG families and provides functional clues for antidiabetes drugs.     

SLC22A12基因第8外显子和第8内含子多态与中国汉族人原发性高尿酸血症关联研究

目的 研究原发性高尿酸血症患者SLC22AI2基因第8内含子和第8外显子单核苷酸多态(single nucleotide polymorphism,SNP)位点与原发性高尿酸血症遗传易感性的关系.方法 选择山东沿海地区原发性高尿酸血症患者215例,正常对照人群323名.提取基因组DNA,PCR扩增SLC22A12基因第8内含子和第8外显子,对PCR扩增产物进行测序.结果 序列分析发现:(1)SLC22AI2基因第8外显子存在T1309C单核苷酸多态,第8内含子存在-103A＞G单核苷酸多态,这2个多态位点完全连锁.(2)高尿酸血症组-103A＞G G等位基因频率和T1309C C等位基因频率明显高于正常对照组(均为51.9%vs.42.4%,P＜0.01);(3)高尿酸血症组GG+GA基因型频率和CC+CT基因型频率显著高于正常对照组(均为80.0%vs.69.0%,P＜0.01).(4)-103 A＞G和T1309C基因多态中,含有等位基因G的基因型GG+GA及含有等位基因C的基因型CC+CT均使高尿酸血症的发病危险性上升了1.79倍(OR=1.79,95%CI:1.19～2.70).结论 SLC22A12基因第8外显子T130gC及第8内含子-103A＞G SNP与原发性高尿酸血症密切相关.     

Mutations in the mitochondrial glutamate carrier SLC25A22 in neonatal epileptic encephalopathy with suppression bursts

Neonatal epileptic encephalopathies with suppression bursts (SBs) are very severe and relatively rare diseases characterized by neonatal onset of seizures, interictal electroencephalogram (EEG) with SB pattern and very poor neurological outcome or death. Their etiology remains elusive but they are occasionally caused by metabolic diseases or malformations. Studying an Arab Muslim Israeli consanguineous family, with four affected children presenting a severe neonatal epileptic encephalopathy, we have previously identified a mutation in the SLC25A22 gene encoding a mitochondrial glutamate transporter. In this report, we describe a novel SLC25A22 mutation in an unrelated patient born from first cousin Algerian parents and presenting severe epileptic encephalopathy characterized by an EEG with SB, hypotonia, microcephaly and abnormal electroretinogram. We showed that this patient carried a homozygous p.G236W SLC25A22 mutation which alters a highly conserved amino acid and completely abolishes the glutamate carrier's activity in vitro . Comparison of the clinical features of patients from both families suggests that SLC25A22 mutations are responsible for a novel clinically recognizable epileptic encephalopathy with SB.     

Immunohistochemical detection of a specific receptor for lipocalin2 (solute carrier family 22 member 17, SLC22A17) and its prognostic significance in endometrial carcinoma

Background

We previously reported the overexpression of lipocalin2 (LCN2), a 25 kDa secretory protein involved in iron-transportation, in endometrial carcinoma and its possible contribution to endometrial carcinogenesis. Recently, a specific receptor for LCN2, solute carrier family 22 member 17 (SLC22A17), was identified. The present study was undertaken to investigate the expression of SLC22A17 in endometrial carcinoma.

Methods

The expression of the SLC22A17 and LCN2 proteins was examined immunohistochemically using 69 cases of endometrial carcinoma and adjacent normal endometrial tissues. Immunoreactivity was evaluated according to the percentage of positive cells and described as a positivity index (PI, full score 100).

Results

The expression of SLC22A17 was negligible in normal endometria, but positive staining for SLC22A17 (PI ≧ 1) was observed in 35 cases of endometrial carcinoma. The PI for SLC22A17 was significantly higher in cases with histological grade 3 (P < 0.0005), advanced FIGO stage (P = 0.002), deep myometrial invasion (P = 0.029), positive lymph-vascular space invasion (P = 0.029), positive intraperitoneal cytology (P = 0.020) and adnexal metastasis (P = 0.029). The expression of SLC22A17 and LCN2 was positively correlated with a significant difference (P = 0.002), and the patients who overexpressed both SLC22A17 and LCN2 showed poorer survival than those without the expression of SLC22A17 or LCN2 (P = 0.002). Moreover, the overexpression of both SLC22A17 and LCN2 was indicated to be an independent prognostic factor by multivariable analysis.

Conclusions

These results suggested that SLC22A17, in cooperation with LCN2, to be involved in the acquisition of aggressive behavior among endometrial carcinoma cells.     

A novel, putative gain-of-function haplotype at SLC6A4 associates with obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is a disabling neuropsychiatric illness with strong segregation data indicative of major genetic contributions. Association analyses of common functional variants of the serotonin transporter gene (SLC6A4), a long-standing OCD candidate, have so far been inconsistent. Here, we set out to investigate the role of additional functional SLC6A4 loci in OCD. We describe a common, functional C > T single nucleotide polymorphism, rs25532, located less than 150 nucleotides centromeric of the serotonin transporter-linked polymorphic region indel known as 5-HTTLPR. The minor allele of rs25532 significantly decreased luciferase reporter gene expression levels by 15-80%, depending on 5-HTTLPR allele background and cell type. Haplotype-based testing of rs25532 and all other known non-coding functional SLC6A4 variants revealed a highly significant omnibus association with OCD in a large case-control sample. Remarkably, the haplotype significantly overrepresented in probands contained the higher-expressing allele at each locus, supporting the notion of increased serotonin transporter functioning being pathogenetically involved in OCD. Conditional haplotype analyses with the software WHAP revealed that this association is primarily driven by 5-HTTLPR, rs25532 and rs16965628. Our results contribute to a better understanding of SLC6A4 expression genetics and provide a functional haplotype framework for future serotonin-related studies.     

Screening of genetic variations of SLC15A2, SLC22A1, SLC22A2 and SLC22A6 genes

A growing list of membrane-spanning proteins involved in the transport of a large variety of drugs has been recognized and characterized to include peptide and organic anion/cation transporters. Given such an important role of transporter genes in drug disposition process, the role of single-nucleotide polymorphisms (SNPs) in such transporters as potential determinants of interindividual variability in drug disposition and pharmacological response has been investigated. To define the distribution of transporter gene SNPs across ethnic groups, we screened 450 DNAs in cohorts of 250 Korean, 50 Han Chinese, 50 Japanese, 50 African-American and 50 European-American ancestries for 64 SNPs in four transporter genes encoding proteins of the solute carrier family (SLC15A2, SLC22A1, SLC22A2 and SLC22A6). Of the 64 SNPs, 19 were core pharmacogenetic variants and 45 were HapMap tagging SNPs. Polymorphisms were genotyped using the golden gate genotyping assay. After genetic variability, haplotype structures and ethnic diversity were analyzed, we observed that the distributions of SNPs in a Korean population were similar to other Asian groups (Chinese and Japanese), and significantly different from African-American and European-American cohorts. Findings from this study would be valuable for further researches, including pharmacogenetic studies for drug responses.