- 學位論文
Triterpenoids抑制Epstein-Barr virus進入溶裂循環
Inhibition of Epstein-Barr virus lytic cycle by triterpenoids
摘要
Epstein-Barr virus (EBV)是人類皰疹病毒，具有潛伏期和溶裂期兩種生活型態。EBV的感染途徑是透過唾液感染上皮細胞和淋巴B細胞，與傳染性單核血球增多症、伯基特淋巴瘤、T細胞淋巴癌、何杰金氏症、胃癌及鼻咽癌等疾病有密切關係。BRLF1和BZLF1是EBV的極早期基因，會轉譯Rta和Zta這兩個轉錄因子進而活化EBV溶裂期的基因表現。目前的抗EBV藥物如acyclovir、ganciclovir及indolocarbazole等主要作用於病毒的DNA聚合酶以抑制病毒的溶裂複製。然而病毒常常會突變而產生抗藥性的突變株，因此需要更新穎的藥物及治療方法。Triterpenoids (三萜類)是由三十個碳元素為骨架之天然化合物，普遍存在於植物或真菌中，具有抗發炎、抗腫瘤、抑制細胞增生及誘導細胞凋亡機制的調節作用。本篇研究的目的是探討triterpenoids的衍生物JYK-MA-37對抑制EBV溶裂期的效果。首先將P3HR1細胞以不同濃度的JYK-MA-37處理，接著並以sodium butyrate (SB)及12-O-tetradecanoylphorbol-13-acetate (TPA)誘導EBV進入溶裂循環，利用西方點墨法與流式細胞分析，結果顯示10 μM的JYK-MA-37有效地抑制EBV的溶裂期蛋白質Rta、Zta及EA-D的表現，其EC50-Rta為11.32 μM，CC50為55 μM。接著，以冷光酵素活性分析測試JYK-MA-37對活化BRLF1與BZLF1啟動子Rp及Zp的影響，結果發現EBV溶裂期極早期基因BRLF1及BZLF1的轉錄活性會被抑制。利用即時聚合酶連鎖分析JYK-MA-37對EBV顆粒產生的影響，結果發現JYK-MA-37會抑制EBV顆粒的產生。綜合以上實驗結果，證明JYK-MA-37具有抑制EBV溶裂循環的能力。
並列摘要
Epstein-Barr virus (EBV) is a human herpesvirus, which has two different life cycles: latent and lytic. EBV infects lymphoid and epithelial cells. Infection by this virus causes infectious mononucleosis and is closely related to several malignant diseases, including Burkitt’s lymphoma, T-cell lymphoma, Hodgkin’s disease，gastric cancer and nasopharyngeal carcinoma. At the onset of the EBV lytic cycle, the virus expresses two immediate-early genes, BRLF1 and BZLF1, which encode transcription factors, Rta and Zta, respectively. These two transcription factors are required to activate the EBV early genes and lytic cascade. Clinically effective anti-EBV drugs that target EBV-encoded DNA polymerase, including acyclovir, ganciclovir and indolocarbazole, are commonly used for inhibiting the lytic cycle of EBV. However, viruses are potentially mutagenic for resistance to drugs. In light of this, it is necessary to identify new targets for antivirus chemotherapy and to develop new treatment strategies. Triterpenoids are formed from six isoprene units with 30 carbons. As it is generally known, triterpenoids are major constituents in several herbal remedies or fungi that are reported to have the capacity of anti-inflammatory, anticancer, repressing cell proliferation, inducing cell apotosis program, etc. The purpose of this study is to demonstrate the effect of JYKMA-37, one of the derivatives of triterpenoids, on repressing the EBV lytic cycle. First of all, P3HR1 cells were treated with different concentrations of JYK-MA-37, and then induced the EBV lytic cycle by sodium butyrate (SB) and 12-O-tetradecanoylphorbol-13-acetate (TPA). Immunoblot analysis and flow cytometry analysis were performed, the results showed that JYK-MA-37 at 10 μM effectively inhibits the expression of EBV lytic protein, including Rta、Zta and EA-D, after lytic induction in P3HR1 cells (EC50 = 22.083 μM，CC50 = 11.32 μM). Moreover, transient transfection analysis revealed that transactivation of BRLF1 promoter (Rp) and BZLF1 promoter (Zp) were inhibited by JYK-MA-37 in a dose-dependent manner. Finally, real-time PCR showed that JYK-MA-37 substantially reduces the numbers of EBV particles produced by the cells after lytic induction. Taken together, this study demonstrated that JYK-MA-37 poccess the capacity of inhibiting the progression of EBV lytic cycle.
參考文獻
延伸閱讀
- 謝宜君（2007）。Moronic acid抑制Epstein-Barr病毒進入溶裂循環〔碩士論文，高雄醫學大學〕。華藝線上圖書館。https://doi.org/10.6832/KMU.2007.00113
- Jiang, Y. W. (2009). 腫瘤壞死因子TNFα誘發基因表現之機轉Part I: 組蛋白去乙醯化酵素抑制劑trichostatin A對環氧化酵素COX-2基因表現的抑制作用Part II: RNA結合蛋白tristetraprolin的後轉錄調節 [master's thesis, National Taiwan University]. Airiti Library. https://doi.org/10.6342/NTU.2009.02101
- 周廷光、簡錦忠（1972）。抗生物質Polyoxin B對Pyricularia oryzae及Alternaria spp.菌絲與胞子之抑制作用。中華農業研究，21(1)，47-54。https://doi.org/10.29951/JARC.197203.0007
- 陳心慧（2011）。Pheophytin b抑制LPS刺激之巨噬細胞Nitric Oxide Synthase-2及cyclooxygenase-2合成〔碩士論文，高雄醫學大學〕。華藝線上圖書館。https://doi.org/10.6832/KMU.2011.00061
- 張式欣（2004）。Inhibition of Epstein-Barr Virus Lytic Cycle by RNA Interference〔碩士論文，國立臺灣大學〕。華藝線上圖書館。https://doi.org/10.6342/NTU.2004.01380