探討血管收縮素轉化酶抑制劑對於神經細胞中ACE基因與tau蛋白質表現

Effect of ACE inhibitor on ACE gene and tau protein expression in neurons.

簡薏(I Chien)

指導教授 ： 吳世忠

高雄醫學大學/健康科學院/醫學檢驗生物技術學研究所/碩士(2014年)

摘要

阿茲海默症是一種神經退化性疾病，神經細胞的功能會漸進式的喪失，導致記憶和認知功能的障礙。在人口老化的社會，阿茲海默症的患者也隨之增加，但是到目前為止，並沒有一個方法可以有效的治療。有研究指出ACE(angiotensin-converting enzyme)抑制劑可以減緩認知功能障礙，但其中的機制還不清楚。
在我們先前的研究指出，ACE基因中的Alu 片段會調控ACE啟動子的轉錄活性，由於有研究顯示ACE抑制劑會促進ACE基因表現，我們將探討ACE抑制劑對於ACE I/D型基因的ACE啟動子轉錄活性調控。使用同步轉染的方式在神經細胞SH-SY5Y內，置入含有ACE I/D型基因質體。我們證實了加入ACE抑制劑後，神經細胞內ACE基因啟動子轉錄活性增加，並且ACE I基因型比ACE D基因型啟動子轉錄活性較高。
Tau蛋白的過度磷酸化是阿茲海默症的病理特徵之一，而ACE抑制劑會活化細胞內的ACE訊息傳導，因此我們將探討ACE抑制劑是否會調控神經細胞內tau蛋白的磷酸化，與觀察訊息傳遞分子GSK3β (glycogen synthase kinase 3 beta)、PP2A(protein phosphatases 2A)、CK2(casein kinase 2)與AKT(protein kinase B)表現。在我們利用okadaic acid導致的tau蛋白過度磷酸化的細胞模式，結果顯示ACE抑制劑可以使tau 蛋白磷酸化表現量下降。我們的結果證明了在ACE抑制劑刺激下，ACE I/D基因型的ACE啟動子活性不同，並且ACE抑制劑可以減緩神經細胞內tau蛋白的磷酸化，ACE抑制劑或許對於阿茲海默症有保護的效果。

關鍵字

阿茲海默症 ； 血管收縮素轉換酶抑制劑 ； tau蛋白

並列摘要

Alzheimer's disease (AD) is a neurodegenerative disease with progressive loss of neuronal functions, which in turn results in memory deficits, cognitive deterioration, and impaired motor coordination. The growing aged population has led to an increased prevalence of AD. However, there is no effective treatment to halt the progression or prevent the onset of AD. Previous studies have indicated angiotensin-converting enzyme (ACE) () inhibitor improved the cognitive impairment, but the mechanisms are still unclear.
Our previous finding indicated that Alu sequence in human ACE gene possesses a regulatory function on the ACE promoter activity in neurons. Moreover, a previous study indicated that ACE inhibitor enhanced ACE gene expression. We aimed to investigate the pharmacogenetic effect of ACE inhibitors on ACE I/D polymorphism. We used transient transfection and reporter assay to examine the intracellular ACE signaling pathway in SH-SY5Y cells. We find that lisinopril , a ACE inhibitor, enhances ACE promoter transcriptional activity and that the ACE I/D polymorphism differently responds to lisinopril in regulating ACE promoter activity in neurons.
The hyper-phosphorylated tau protein has been one of hallmarks for AD. In this study, we also aimed to investigate whether ACE inhibitors regulate hyper-phosphorylated tau protein in neuron and to observe whether the regulators of phosphorylated tau are affected by ACE inhibitors, including GSK3β (glycogen synthase kinase 3 beta), AKT(protein kinase B), PP2A(protein phosphatase 2A). We find that lisinoplril could decrease the hyper-phosphorylation of tau protein induced by okadaic acid. Our results show ACE inhibitors have pharmacogentic effect on ACE gene and might protect neurodegeneration from hyperphosphorlated of tau protein.

並列關鍵字

ACE inhibitor ； tau protein

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