WOX1調控神經細胞死亡的機制研究

Studies on the Role of WOX1 in Regulating Neurooal Death

蔡明世(Ming-Shih Tsai)

《中南盟研究年刊》 3卷1期 (2010/03) Pp. 17-26

https://doi.org/10.6850/JCSMA.201003_3(1).0002

摘要

目的：WOX1是一個在玻尿酸酶、紫外光或毒物刺激之下，會大量表現的蛋白質。研究指出，WOX1可以增加癌症細胞對於腫瘤壞死因子(Tumor necrosis factor)的敏感性，增強毒殺效果。在外來的刺激之下，WOX1的酪氨酸33會磷酸化，並且與抑癌因子p53或轉錄因子c-Jun N-terminal protein Kinase 1 (JNK1)結合。腦中風是國人十大死因之一，由於腦內血管出血或阻塞，局部的缺血及缺氧性傷害，引發神經細胞死亡。缺氧誘發因子(HIF-1α)在細胞缺氧的時候，會調控多種訊息傳遞路徑。由於缺氧誘發因子HIF-1α和p53共同作用，使神經細胞死亡的進程得以延後，而且WOX1可以與p53結合而調控細胞凋亡，於是推測WOX1亦與缺血性傷害引發之神經凋亡。方法，利用神經瘤細胞SK-N-SH，結合基因轉殖的技術，我們將建立WOX1過量或缺失表現的模式，研究WOX1表現量的改變，對於缺血性傷害的影響，並釐清WOX1的活化，與缺氧相關因子的調控關係，期望基礎研究應用於臨床藥物的開發與治療。結果：透過缺氧的刺激，我們發現細胞走向典型的凋亡路徑。西方點墨法的分析顯示，缺氧誘發因子HIF-1α快速的增加，反應細胞正受到缺氧的刺激。同時WOX1的表現與磷酸化與缺氧的刺激有關，而且發生的時間點較早。利用免疫沉澱法，我們觀察到WOX1會與JNK1結合。結論：WOX1與JNK1的結合，是導致JNK1活化，或抑制其活化仍無法確定。後續的研究，仍可朝WOX1如何調控JNK1活化作探討。初期缺氧時結合比率的上升與後期時比率的下降，可能與改變JNK1調控路徑有關，值得深入研究。

關鍵字

WOX1 ； 腦中風 ； 神經 ； 細胞凋亡

並列摘要

Objectives. WOX1 is over-expressed under administration of hyaluronidase, UV irradiation or toxic drugs. In previous studies, WOX1 increased the cytotoxicity of tumor necrosis factor (TNF) in several cancer cell lines. Under stress damage, WOX1 is phosphorylated at its tyrosine (T33) and interacted with tumor suppressor p53 or transcription factor c-Jun-N-terminal kinase 1 (JNK1). WOX1 is known to involve in regulating cell apoptosis, but the detail molecular mechanism remains unknown. Stroke is one of the top ten causes of death. It is caused by cerebral arteries bleeding or occlusion. Ischemic or hypoxic damage may contribute to neuronal cell death. Hypoxic induced factor 1 (HIF-1α) modulates several signal transduction pathway under hypoxia. It protects p53 from degrading by MDM2. Under hypoxic condition, p53 activity is conserved by HIF-1α, and able to regulate hypoxia-associated gene transcription. Apoptosis of neuron cells is delayed under HIF-1α and p53 co-activation.
Methods. We set up a WOX1-overexpression/knock out cell model by using transfection technology. Thus, we may be able to study that if high/low expression of WOX1 affects neuronal cell death during ischemic/hypoxic damage. This may provide basic mechanism in clinical therapy.
Results. Typical cells apoptotsis was observed after hypoxic damage. HIF-1α expression was increased which indicated hypoxic condition. Expression and phosphorylation of WOX1 was associated with hypoxic stimulus. By immuno-precipitation, the interaction of WOX1 and JNK1 was detected.
Conclusions. Does the interaction of WOX1 and JNK1 affect JNK1 phosphorylation remains unknown. It is worthy to investigate the possible mechanism of WOX1-induced JNK1 phosphorylation. The interaction intensity of WOX1 and JNK1 was decreased after hypoxic damage, might be an interesting issue on WOX1-mediated hypoxic cell death.

並列關鍵字

neuronal cell death ； WOX1 ； hypoxic/ischemic damage