僵直性脊椎炎及貝賽特氏病與IκBα promoter之相關性及其功能性研究

IκBα promoter polymorphisms and functional significance in patients with Ankylosing Spondylitis and Behcet’s disease

洪毓鴻(Yu-Hung Hung)

指導教授 ： 顏正賢

高雄醫學大學/醫學院/醫學研究所/碩士(2010年)

https://doi.org/10.6832/KMU.2010.00027

摘要

僵直性脊椎炎為一種慢性發炎的風濕性疾病，主要侵犯脊柱與薦腸關節等 中軸骨骼。貝賽特氏病是以細小血管炎為病理基礎的全身性疾病。兩者皆屬 於自體免疫疾病，雖至目前尚無確切原因解釋疾病的發生，但普遍認為 與 遺傳及環境共同誘導之免疫異常有關。NF-κB 是促使發炎基因表現最重要的 轉錄因子，當 NF-κB 的抑制者，IκBα因各種原因無法對其產生作用時，很可 能 NF-κB 會不受控制的大量活化而導致許多發炎基因過量且持續表現，最後引 發疾病。Promoter 是調控下游基因最重要的位置，本實驗針對 IκBα promoter -881A/G、-826C/T、-550A/T、-519C/T 及-297C/T 以 PCR-RFLP 進行分析來討論此些 SNP 與上述兩種疾病的相關性，接著再利用 Luciferase reporter assay 更深入研究不同 Haplotype 的 IκBα promoter 之活性差異。結果發現，在台灣，-826T allele 及 TT、CT genotypes 皆與僵直性脊椎炎和貝賽特氏病的發病有關係，尤其-826 TT genotype 更在貝賽特氏病人的皮膚病變上佔有重要的地位。而 haplotype -881A -826T -550A -519C -297C、-881A -826C -550A -519T -297C 以及-881A -826T -550A -519C -297C、-881A -826T -550A -519T -297C 則分別提高僵直性脊椎炎和貝賽特氏病的易感性，但-881A -826C -550A -519C -297C haplotype 卻皆是有意義的下降。另外，-826C -550A -519T、-826T -550A -519T 的 IκBα promoter 活性較其他組別為低，其正符合上述兩種疾病易感性之結果，而-826C -550A -519C 造成下游基因的高表現也如同預期。本研究結果證實，IκBα promoter 基因多形性與僵直性脊椎炎及貝賽特氏病之疾病易感性與臨床表徵有很大的相關性。

關鍵字

僵直性脊椎炎 ； 貝賽特氏病

並列摘要

Ankylosing spondylitis (AS) is a chronic inflammatory rheumatic disease characterized primarily by involvement of the axial skeleton including sacroiliac joint and spine. Behcet’s disease (BD) is a systemic disease based on vasculitis of small vessels. Both AS and BD belong to autoimmune diseases, but the etiology of this two diseases are unclear. It is believed to be due to an abnormal immune response triggered by environmental agents in a genetically predisposed individual. NF-κB is the most important regulator in the expression of the pro-inflammatory cytokine genes. If IκBα, the inhibitor of NF-κB, cannot retain NF-κB in cytoplasm, the diseases might be developed. Out of control on NF-κB will induce overexpressions of the immune associated genes. Promoter is the most important site to regulate the gene expression. In this study, we investigate the association of IκBα promoter polymorphisms with AS and BD, the IκBα −881 A/G, −826 C/T, −550 A/T, −519 C/T and −297 C/T polymorphisms were determined by the polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP)method. Furthermore, Luciferase reporter assays were used to measure the activities of different haplotypes of IκBα promoter. This study demonstrated that IκBα -826T allele and CT, TT genotypes were associated with AS and BD in Taiwan. Especially, the -826TT genotype was associated with the development of skin lesion in BD. In addition, IκBα -881A -826T -550A -519C -297C, -881A -826C -550A -519T -297C and -881A -826T -550A -519C -297C, -881A -826T -550A -519T -297C haplotypes might be related to susceptibility to AS and BD, respectively. In contrast, -881A -826C -550A -519C -297C haplotype frequency was significantly lower in these two diseases. On the other hand, IκBα promoter activity in frequencies of haplotype of -826C -550A -519T and -826T -550A -519T were lower than that of the others. In conclusion, IκBα promoter polymorphisms are related to the sustability and clinical manifestation of AS and BD.

並列關鍵字

IκBα ； NF-κB ； promoter

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