TNF-α及IL-1α基因啟動子多型性與台灣帕金森氏症感受性的分子遺傳學研究

Molecular genetic study of TNF-α and IL-1α promoter polymorphisms in Parkinson's disease in Taiwan

馮宜欣(I-Hsin Feng)

指導教授 ： 李桂楨

國立臺灣師範大學/理學院/生命科學研究所/碩士(2005年)

摘要

帕金森氏症(Parkinson's disease； PD)是常見的漸行性神經退化性症病之一，其臨床病症主要表現於運動失調上，患者中腦黑質的緻密區(substantia nigra pars compacta)會有多巴胺神經元死亡的現象，部分檢體的神經元突起處或是細胞核周圍會出現嗜伊紅性的細胞質內蛋白質包涵體，包含環境毒素、氧化壓力、細胞發炎反應、遺傳因素等都是可能造成PD發病的原因
本研究主要在著重在tumor necrosis factor-α (TNF-α)啟動子T-1031C、C-863A、C-857T、G-308A及interleukin-1α (IL-1α)啟動子C-889T多型性與PD易感受性的相關研究。在遺傳層面上發現T-1031C、C-857T在PD病患與控制組間有顯著的差異(P = 0.0062及0.0035)，但只有-1031CC基因型與PD的易感受性有關(Odds ratio: 2.96，95% CI: 1.38-7.09，P=0.0085)。利用SNPSpD分析發現-1031與-863有強力聯鎖情形(D'=0.93，Δ2=0.80)，且-1031C/-863A的單套型也與PD的易感受性有關(Odds ratio=2.18，95% CI: 1.33-3.69，P=0.0028)。在基因功能性層面上的研究發現Raji細胞中-1031C會有較高的轉錄活性，-308A則有偏低的活性，使用ConA處理可誘發-1031C更高轉錄活性的表現，淋巴細胞株的研究則顯示帶有-1031CC/-863AA基因型其TNF-α mRNA表現量有些微增加的現象。
IL-1α啟動子的研究上發現C-889T多型性在整體PD病患及控制組間並無顯著差異，但以發病年齡做區分可發現具-889 CT基因型的人其老年罹患PD的危險性會有顯著下降的情形(Odds ratio=0.31，95% CI: 0.13-0.71，P=0.0071)，且TNF-α -1031T、-863C、-857C對偶基因對-889 CT基因型有顯著的加成效應。
總結本研究發現無論在基因層面上TNF-α啟動子-1031CC的基因型具有較高罹患PD的危險性，且因強力聯鎖緣故，所以-1031C/-863A的單套型也具有較高罹患PD的危險性。功能性的研究也證實在Raji細胞系統中-1031C帶有較高的轉錄活性，ConA的處理則可增加-1031C高轉錄活性的效應。IL-1α -889 CT的基因型在大於70歲發病的PD族群中與控制組間有顯著的差異，顯示具有CT基因型的人老年時會有較低罹患PD的危險性，且TNF-α啟動子常見的多型性對偶基因對CT基因型有顯著的加成效果，其組合也會減少老年時罹患PD的危險性

關鍵字

帕金森氏症 ； 腫瘤壞死因子 ； 間白素-1 ； 啟動子多型性

並列摘要

Parkinson’s disease (PD) is one of the most common neurodegenerative movement disorder. The hallmarks of PD are death of dopamine neurons in substantia nigra pars compacta and eosinophilic inclusions around the nucleus of neuron from PD patients. The etiology of PD is still not fully understood, but environmental toxicants, oxidative stress, inflammation, and gene dysfunction have thought to evoke PD.
The focus of the study is to investigate the association of tumor necrosis factor-α (TNF-α) and interleukin-1α (IL-1α) promoter polymorphisms with the risk of PD. The overall genotype distribution at T-1031C and C-857T sites showed significant difference between PD cases and controls (P=0.0062 and 0.0035, respectively). However, only the more frequent -1031 CC genotype was evidently associated with PD (Odds ratio: 2.96, 95% CI: 1.38-7.09, P=0.0085). Using SNPSpD method showed that -1031 and -863 are in strong linkage disequilibrium (D'=0.93, Δ2=0.80). Pairwise Haplotype analysis among the four sites showed that -1031C-863A may act as a risk haplotype among PD cases (Odds ratio=2.18, 95% CI: 1.33-3.69, P=0.0028). Functional study revealed that -1031C allele drove greater transcriptional activity than common allele in Raji cell line. After stimulation with Concanavalin A (ConA), -1031C promoter activity was promoted to a significantly higher level than that of no stimulation. Using lymphoblastoid cells carrying -1031 CC/-863 AA genotype resulted in higher expression of TNF-α compared to cells carrying -1031 TT/-863 CC genotype.
For IL-1α gene, the overall genotype distribution was not significantly different at C-889T site. However, when PD and control groups were stratified into >70 years subgroup the CT genotype frequency in PD was significantly less than controls (Odds ratio: 0.31, 95% CI: 0.13-0.71, P=0.0071). It suggested that people carrying -889 CT genotype reduced the probability of PD emergence, even aged. Multivariate analysis demonstrated the possible synergistic effect of the TNF-α promoter common alleles (-1031T, -863C, -857C) to IL-1α CT genotype in control group.
In summary, the study demonstrated the association between the TNF-α -1301CC genotype, -1031C/-863A haplotype and susceptibility to PD. In Raji cell line, after stimulation with ConA -1031C allele drove significantly higher transcriptional activity than common allele, even before stimulation. In the onset age > 70 years subgroup, PD carrying IL-1α promoter CT genotype frequency was significantly less than controls, and the synergistic effect of the TNF-α promoter common alleles (-1031T, -863C, -857C) to IL-1α CT genotype in control group.

並列關鍵字

Parkinson's disease ； TNF-α ； IL-1α ； promoter SNP