【作者】 丁虎；

【导师】 汪道文；

【作者基本信息】 华中科技大学 ， 分子生物学与生物化学， 2010， 博士

【摘要】 [研究目的]对白种人缺血性脑卒中的第一个全基因组关联研究(GWAS)确定了多个易感性基因座位。我们在中国汉族人中重复验证了这些位点和缺血性脑卒中的关联性。[研究方法]采用TaqMan-MGB探针法,在包括1123个缺血性脑卒中病例(血栓性卒中716例,腔隙性脑梗塞407例)和557个正常对照的样本中,对上述报道的25个常见阳性位点进行了基因分型。并在单核甘酸多态性和单体型水平进行了关联分析,还使用了错误发现率(FDR)q值来进行多重检验的校正。[实验结果]rs11052413,一个位于基因之间的单核甘酸多态性,在加性模型(OR=1.51,95%CI=1.19-1.92,p=7.4×10-4,q=0.018)和显性模型(OR=1.59,95%CI=1.20-2.08,p=9.2×10-4,q=0.023)中独立于传统的心脑血管病危险因素与缺血性脑卒中显著关联。位于ZNF650基因内含子的rs10204475和基因间的单核甘酸多态性rs10486776都在显性模型中均独立于传统的心血管危险因素与缺血性脑卒中相关联(OR=1.47,95%CI=1.12-1.96,p=0.005,q=0.040和OR=1.53,95%CI=1.15-2.02,p=0.003,q=0.036)。卒中亚型分析在多重校正后未发现有统计学意义的阳性结果。[实验结论]我们在中国汉族人中证实了之前报道的缺血性脑卒中和rs11052413、rs10486776、和ZNF650基因的rs10204475之间的关联。然而,这些遗传变异在脑卒中发挥作用的机制有待进一步阐明。中文摘要[研究目的]非对称甲基精氨酸(ADMA),一种内源性的精氨酸的类似物,通过抑制一氧化氮的生成在内皮功能失调中发挥着非常重要的作用。在本研究中,我们考察了位于非对称甲基精氨酸水解酶(DDAH1)基因启动子区一个新的多态性位点是否改变了脑卒中与冠心病的遗传易感性。[研究方法和实验结果]通过对DDAH1基因再测序,在该基因的启动子区我们发现了一个4个碱基插入／缺失的新的多态性位点。其中插入型等位基因破坏了金属调节转录因子1(MTF1)与多态性位点结合,能引起体外DDAH1基因体外转录活性和体内mRNA水平的显著降低,并造成血浆ADMA水平和ADMA/L-精氨酸比值升高。我们首先用TaqMan探针法,在包括1388个脑卒中和1027个对照的样本中以及576个冠心病和557个对照样本中进行基因分型,然后在在包括961个脑卒中和822个对照的样本中以及482个冠心病和1072个对照样本中重复验证上述关联性。我们发现DDAH1基因的启动子区-396位的4个碱基插入等位基因独立于传统的心脑血管病危险因素与血栓性脑卒中和冠心病显著关联。(血栓性脑卒中发现人群：OR=1.35,p=0.032；重复人群：和OR=1.51,p=0.006；冠心病发现人群,OR=1.45,p=0.035；重复人群：和OR=1.47,p=0.003)。[实验结论]我们的研究提示DDAH1基因功能失活的多态性与血栓性脑卒中和冠心病的遗传易感性相关。更多还原

【Abstract】 Background and Purpose—The first genome-wide association (GWA) study of ischemic stroke on Caucasians has identified multiple susceptibility loci. Here we confirmed this study by examining associations with ischemic stroke in Chinese Han population.Methods—Twenty five common variants were genotyped in a relatively large sample size including 1123 subjects with ischemic stroke cases (thrombosis stroke=716, lacunar infarction=407) and 557 normal controls. The association analyses were performed at both SNP and haplotype levels. FDR q value method was applied for multiple testing corrections.Results—Rsl1052413, a intergenic SNP, was most significantly associated with ischemic stroke independent of traditional cardiovascular risk factors in additive (OR=1.51,95% CI: 1.19-1.92, P=7.4×10-4, q=0.018) and dominant model (OR=1.59,95% CI:1.20-2.08, P= 9.2×10-4, q=0.023). In addition, both ZNF650 rs10204475 and intergenic SNP rs10486776 were associated with ischemic stroke as well independent of traditional cardiovascular risk factors in dominant models (OR=1.47,95% CI:1.12-1.96, P=0.005, q=0.040; OR=1.53, 95% CI:1.15-2.02, P=0.003, q-0.036; respectively). No significant results were found in stroke subtype analysis after multiple corrections.Conclusion—Our study confirmed previously reported associations between ischemic stroke and rs11052413, rs10486776 and ZNF 650 rs10204475 in Chinese Han population. The mechanism whereby the genetic variants exert their effects on ischemic stroke remains to be further elucidated. Background and Purpose—Asymmetrical dimethylarginine (ADMA), an endogenous arginine analogue, inhibits nitric oxide synthases and plays an important role in endothelial dysfunction. In the present study, we tested whether a novel genetic variant in dimethylarginine dimethylaminohydrolasel (DDAH1), an important ADMA hydrolyzing gene, was associated with stroke and coronary heart disease (CHD) susceptibility in the Chinese Han population.Methods and Results—By resequencing, we identified a novel 4-nucleotide deletion/insertion variant in the DDAHl promoter. The insertion allele disrupted binding of metal-regulatory transcription factor 1 (MTF1), which resulted insignificant reduction of in vitro DDAH1 transcriptional activity and in vivo DDAH1 mRNA level, and in turn, increased plasma ADMA level and the ratio of ADMA to L-arginine. We initially genotyped the polymorphism in 1388 stroke patients and 1027 controls as well as 576 CHD patients and 557 controls and then replicated our study in additional independent case-control cohorts comprising 961 stroke patients and 822 controls and 482 CHD patients and 1072 controls. We identified that the-396 4N ins allele was significantly associated with increased risk of thrombosis stroke and CHD after adjusting for environmental factors in both samples for both diseases (thrombosis stroke discovery set:odds ratio [OR]=1.35, P=0.032; replication set:OR=1.51, P=0.006; CHD discovery set:OR=1.45,P=0.035; replication set:OR=1.47, P=0.003).Conclusion—Our results suggest that the DDAH1 loss-of-function polymorphism is associated with both increased risk of thrombosis stroke and CHD.更多还原