| 摘要: | 研究背景：活化轉錄因子3(ATF3)為一種壓力誘導基因，屬於哺乳類ATF/CREB鹼性區域白胺酸夾鏈(bZip)蛋白轉錄因子家族的一員，當細胞暴露於壓力訊號時，ATF3 mRNA表現會隨之增加。研究也指出心臟中缺血-再灌輸(ischemia/reperfusion)、阿黴素(doxorubicin)與神經荷爾蒙(neurohormonal)會促進心肌細胞中ATF3之表現。由主動脈縮窄術之壓力過荷模式的小鼠中文獻中發現，ATF3的缺失促使心臟肥大；此外，於體外ATF3剃除鼠實驗模式中也發現內皮素誘導心肌細胞肥大的不良反應，顯示出ATF於心臟中可能扮演一個正向的角色。相反地，轉基因小鼠中，ATF3的表現造成心房肥大、心臟纖維化、心臟傳導障礙以及猝死，顯示出ATF3反向的影響。
研究目的：為探討ATF3在人類心血管疾病之病理生理學中所扮演的角色，聚焦於心臟傳導的部分，評估ATF3單一核苷酸多型性(Single Nucleotide Polymorphism, SNP)基因變異和台灣人族群心電圖參數之間的相關性分析。
研究方法：本研究使用來自2004年台北長庚紀念醫院健康檢查中心之臺灣民眾去連結檢體作為分析樣本，共520位，其中包含264位男性及256位女性受試者。基因多型性鑑定採用的方法為聚合酶連鎖反應限制酶長度片段多形性(Polymerase Chain Reaction- Restriction fragment length polymorphism，PCR-RFLP)和TaqMan SNP Genotyping Assay得到活化轉錄因子3基因型的結果(SNP genotyping data)，接著使用Statistical Product and Service Solutions (SPSS) 統計軟體分析基因型與心電圖參數之間的關係，再者利用Golden helix軟體演算活化轉錄因子3之單倍型與心電圖參數間之關係性。
結果：觀察樣本共520位，其中排除年齡十八歲以下、C反應蛋白(CRP)高於10mg/L與服用降血糖、血壓、血脂藥物。本篇研究共分析ATF3基因上五個單一核苷酸多型性變異點(SNP)，藉由聚合酶連鎖反應限制性片段長度多型性(PCR-RFLP)方法檢測出rs12070345、rs2229346與rs10475三個SNP，也藉由TaqMan SNP Genotyping Assay分析出rs1126700與rs9729889兩個SNP。藉由SPSS與軟體計算，經調整臨床共變量過後，我們發現ATF3基因型與單倍型與心電圖參數，包括QTd、Tpe與Tpe/QT之波值具有相關性。在男性族群累加性模式分析中，SNP rs12070345次要對偶基因與Tpe及Tpe/QT波值的增加相關，Bonferroni P值分別為0.005 與 0.01；在顯性模式中也發現Bonferroni P分別為0.005與0.015。藉由Golden helix軟體預測五個ATF3 SNP單倍型之結果發現，在男性族群中，單倍型ACCGC與Tpe及Tpe/QT波值增加具有相關性，Bonferroni P值分別為0.0015與0.0035，但在女性族群中並未發現此關連性。於交互作用分析結果中，發現在Tpe波在性別與ATF3單倍型ACCGC具有相關性，Interaction P值為0.033。
結論：台灣人族群中，活化轉錄因子3之單一核苷酸多型性與心電圖參數QTd與Tpe/QT具有相關性，再者活化轉錄因子3單倍型分析中發現心電圖參數Tpe在性別間具有交互作用。這些發現在日後將可應用做為心室心律失常之預測，期望能作為心臟疾病之預防。
OBJECTIVES：The mammalian ATF/CREB family of transcription factors represents a large group of basic region-leucine zipper (bZip) proteins. ATF3 is a stress-inducible gene with its mRNA level greatly increases upon the exposure of cells to stress signals.
Recently, many insults and signals have been shown to up-regulate cardiac ATF3, including ischemia/reperfusion, doxorubicin, and neurohormonal signals in the heart. ATF3 deficiency has been shown to promote cardiac hypertrophy in an aortic banding pressure overload model. In addition, an ATF3 knock down experiment also showed in an improper response to endothelin-induced cardiomyocyte hypertrophy in an in vitro model suggesting a beneficial effect of ATF3. Conversely, transgenic mice with cardiac ATF3 expression resulted in enlarged atria, fibrosis, conduction defects, and sudden death, suggesting a deleterious effect of ATF3. To further understanding of the novel role of ATF3 in pathophysiology of cardiovascular diseases, focus on heart conduction, we aim to evaluate the association between variations in the ATF3 gene and parameters of electrocardiogram in a Taiwanese population with exclusion criteria of age≧18, CRP≦10mg/L and any drugs for decreasing blood sugar, blood pressure and lipids.
SUBJECTS AND METHODS：A total of 520 Han Chinese subjects (including 264 men, 256 women) from the health center of Chang Gung Memorial Hospital, Taiwan. The genotyping data were determined by polymerase chain reaction followed by restriction fragment length polymorphism (PCR-RFLP) and TaqMan SNP Genotyping Assays, and then used Statistical Product and Service Solutions (SPSS) and Golden helix software to analyze the potential association of genetic variance and parameters of electrocardiogram.
RESULTS：With adjustment for clinical covariates, ATF3 genotypes/haplotypes were found to be associated with parameters of electrocardiogram, including QTd, Tpe and Tpe/QT. For additive model, minor alleles of SNP rs12070345 were associated with increased Tpe and Tpe/QT levels predominantly in male subjects (Bonferroni P=0.005, and P=0.01, respectively). The positive association also existed in dominant model (Bonferroni P=0.005, and P=0.015, respectively). One haplotypes inferred from the 5 SNPs, ACCGC was also associated with increased Tpe and Tpe/QT, respectively, in male subjects (Bonferroni P=0.0015 and P=0.0035, respectively) but not in female subjects. Interaction analysis revealed interaction of gender with an ATF3 haplotype associated with a high Tpe (interaction P=0.033 for haplotype ACCGC).
CONCLUSIONS: ATF3 polymorphisms are associated with parameters of electrocardiogram, including QTd, and Tpe/QT in Taiwanese subjects. Further, ATF3 haplotypes interact with gender to set Tpe. These findings may have implications for the prediction of ventricular arrhythmias. |
