Amino acid metabolism as drug target in autoimmune diseases

In mammals, amino acid metabolism has evolved to control immune responses. Autoimmune diseases are heterogeneous conditions that involve the breakdown of tolerogenic circuitries and consequent activation of autoreactive immune cells. Therefore, critical enzymes along amino acid degradative pathways may be hijacked to keep in check autoimmunity. We examined here current knowledge of indoleamine 2,3-dioxygenase 1 (IDO1) and arginase 1 (ARG1), the main enzymes catabolizing tryptophan and arginine, respectively, in organ-specific and systemic autoimmune diseases as well as in the development of autoantibodies to therapeutic proteins. At variance with neoplastic contexts, in which it is known to act as a pure immunosuppressive molecule, ARG1 exhibited a protective or pathogenetic profile, depending on the disease. In contrast, in several autoimmune conditions, the bulk of data indicated that drugs capable of potentiating IDO1 expression and activity may represent valuable therapeutic tools and that IDO1-based immunotherapeutic protocols could be more effective if tailored to the genetic profile of individual patients.     

应用RFLP-VNTR分型进行父权鉴定1例

爱父树鉴定委托,经常规血清学方法鉴定,相对父树概率为95.55%为慎重起见又应用限制性片段长度多态性(RFLP)技术检测D2S44、D10S28、D4S163、D4S139、D17S79可变数量串联重复顺序单位(VNT),结果有3个位点可以排队与涉嫌人胎儿与的父子关系,现报告如下:     

MLVA用于新疆部分地区结核分枝杆菌基因分型的初步研究

目的探讨结核菌株进行多位点可变数目串联重复序列分析(the multiple locus VNTR analysis,MLVA)。方法选择2010年至2011年新疆维吾尔自治区第五次结核病流行病学抽样调查资料,采用经典24位点方法进行基因分型。并采用Bio Numerics5.0数据库进行基因聚类分析。将结核分枝杆菌原始株,取一菌环溶于400μl TE中悬菌,80℃1 h灭活,12 000 r/min离心10 min,弃上清,600μl TE重新悬菌,进行多位点串联重复序列分析。结果新疆99株结核分枝杆菌分为2个基因群:分别为基因群Ⅰ和基因群Ⅱ,基因群Ⅰ66株(66.7%),基因株Ⅱ33株(33.3%);基因群Ⅰ是北京家族,基因群Ⅰ的66株结核分枝杆菌有65种不同的基因型,有2株结核分枝杆菌属于同一簇,成簇率为1.5%,基因群II33株结核分枝杆菌菌株的MLVA图谱不同,成簇率为0。结论新疆结核分枝杆菌菌株存在明显的基因多态性,以北京基因型菌株为主,同时还存在一定比例的非北京基因型,应加强对主要流行菌株流行的监控及管理。     

Association between the dopamine transporter gene and the inattentive subtype of attention deficit hyperactivity disorder in Taiwan

Attention deficit hyperactivity disorder (ADHD) is a common heritable childhood psychiatric disorder. Since methylphenidate, one of the main drugs used to treat ADHD, targets the dopamine transporter, this study examined the linkage disequilibrium (LD) structure of the dopamine transporter gene (DAT1) and investigated whether the DAT1 gene was associated with ADHD. This Chinese family-based association sample consisted of 273 DSM-IV diagnosed ADHD probands and their family members (n = 906). We screened 15 polymorphisms across the DAT1 gene, including 14 single nucleotide polymorphism (SNP) markers and the variable number of tandem repeat (VNTR) polymorphism in 3′-untranslated region (3′UTR). Calculations of pairwise LD revealed three main haplotype blocks (HBs): HB1 (intron 2 through intron 6), HB2 (intron 8 through intron 11), and HB3 (3′UTR). Family-Based Association Tests showed that no allele was significantly more transmitted than expected to the ADHD children for these 15 markers. Haplotype-Based Association Tests showed that a haplotype rs27048 (C)/rs429699 (T) was significantly associated with the inattentive subtype (P = 0.008). In quantitative analyses, this haplotype also demonstrated significant association with the inattention severity (P = 0.012). Our finding of the haplotype rs27048 (C)/rs429699 (T) as a novel genetic marker in the inattentive ADHD subtype suggests that variation in the DAT1 gene may primarily affect the inattentive subtype of ADHD.     

Role of gene-gene/gene-environment interaction in the etiology of eastern Indian ADHD probands

Associations between attention deficit hyperactivity disorder (ADHD) and genetic polymorphisms in the dopamine receptors, transporter and metabolizing enzymes have been reported in different ethnic groups. Gene variants may affect disease outcome by acting synergistically or antagonistically and thus their combined effect becomes an important aspect to study in the disease etiology. In the present investigation, interaction between ten functional polymorphisms in DRD4, DAT1, MAOA, COMT, and DBH genes were explored in the Indo-Caucasoid population. ADHD cases were recruited based on DSM-IV criteria. Peripheral blood samples were collected from ADHD probands (N = 126), their parents (N = 233) and controls (N = 96) after obtaining informed written consent for participation. Genomic DNA was subjected to PCR based analysis of single nucleotide polymorphisms and variable number of tandem repeats (VNTRs). Data obtained was examined for population as well as family-based association analyses. While case-control analysis revealed higher occurrence of DAT1 intron 8 VNTR 5R allele (P = 0.02) in cases, significant preferential transmission of the 7R-T (DRD4 exon3 VNTR-rs1800955) and 3R-T (MAOA-u VNTR-rs6323) haplotypes were noticed from parents to probands (P = 0.02 and 0.002 respectively). Gene-gene interaction analysis revealed significant additive effect of DBH rs1108580 and DRD4 rs1800955 with significant main effects of DRD4 exon3 VNTR, DAT1 3′UTR and intron 8 VNTR, MAOA u-VNTR, rs6323, COMT rs4680, rs362204, DBH rs1611115 and rs1108580 thereby pointing towards a strong association of these markers with ADHD. Correlation between gene variants, high ADHD score and low DBH enzymatic activity was also noticed, especially in male probands. From these observations, an impact of the studied sites on the disease etiology could be speculated in this ethnic group.     

1个多发性椎间盘退行性变疾病家系的Aggrecan基因串联重复多态性的分析

  目的 分析1个多发性椎间盘退行性变疾病（DDD)家系的聚合蛋白聚糖（Aggrecan）基因串联重复多态性(VNTR)。方法 应用PCR技术检测家系成员血液中Aggrecan VNTR的分布情况。结果 被检测的家系成员中未发现超过25次重复的等位基因者,家系患DDD成员基因Aggrecan VNTR分布：均为杂合子,且有1个等位基因≤20个重复序列。结论 本家系中遗传因素是DDD的主要诱发因素,且可能与相对较小重复序列Aggrecan VNTR有关。     

Direct application of variable number tandem repeats polymerase chain reaction in clinical samples obtained from patients with meningococcal disease

A nested variable number tandem repeats (VNTR) polymerase chain reaction (PCR) technique was developed for the direct typing of meningococcal PCR-positive clinical samples. The system was evaluated on a panel of 43 clinical samples and isolates positive for Neisseria meningitidis. The results revealed that VNTR-PCR can be used directly in clinical samples, allowing fine typing of N. meningitidis.     

CTLA4 gene polymorphism contributes to the mode of onset of diabetes with antiglutamic acid decarboxylase antibody in Japanese patients: genetic analysis of diabetic patients with antiglutamic acid decarboxylase antibody.

AIM: The mode of onset is occasionally similar in Type 1 and Type 2 diabetes mellitus, and some patients with Type 2 diabetes are positive for antiglutamic acid decarboxylase antibody (GAD Ab). We investigated the contribution of Type 1 diabetes susceptibility genes to the progression of the insulin-deficient state and mode of onset of Type 2 diabetes in GAD Ab-positive (GAD-Ab+) patients. We examined the variable number of tandem repeats in the promoter region of the insulin gene (INS-VNTR, insulin-dependent diabetes mellitus (IDDM) 2) and cytotoxic T lymphocyte antigen 4 (CTLA4, IDDM12) as representative of Type 1 diabetes susceptibility genes. METHODS: Patients with Type 2 diabetes who were GAD-Ab+ (n = 51) were selected for this study. In INS-VNTR, the class I allele was classified according to length (1S, 25-38 repeat units; 1M, 39-41 repeat units; 1L, 42-44 repeat units) and the exact class I allele length was analysed by specific polymerase chain reaction (PCR) amplifications. Analyses of classes II and III were performed by Southern blot. CTLA4 gene polymorphism (exon 1 position 49, G/A) was analysed by PCR-restriction fragment length polymorphism. RESULTS: The distribution of INS-VNTR was no different between Type 1 diabetes and Type 2 diabetes with GAD Ab. The allele frequencies of CTLA4 gene polymorphism G and A in Type 2 diabetes/GAD-Ab+ were significantly different from those of Type 1 diabetes/GAD-Ab+ (G: 53%, A: 47% vs. G: 84%, A: 16%; P < 0.0001). CONCLUSIONS: Our data showed that GAD-Ab+ Japanese patients presenting with Type 2 diabetes have shifted A allele while patients with abrupt onset have shifted G allele of CTLA4 gene polymorphism. Our results suggest that immunological function and polymorphism of the CTLA4 gene may contribute to the pathogenesis and progression of Type 1 diabetes.