埃及斑蚊熱休克蛋白90與茲卡病毒非結構性蛋白NS3之交互關係研究

Study of the Zika virus NS3 protein and Hsp90 interaction on virus replication in the mosquito Aedes aegypti

徐慧真(Hui-Zhen Xu)

指導教授 ： 蕭信宏

共同指導教授 ： 洪健清(Chien-Ching Hung)

國立臺灣大學/醫學院/微生物學研究所/碩士(2020年)

https://doi.org/10.6342/NTU202002280

摘要

蚊子是許多傳染病的主要病媒，舉凡瘧疾、絲蟲病、日本腦炎、登革熱、屈躬病，乃至近年爆發的茲卡病毒感染症 (Zika virus infection)，皆是經由不同種類的病媒蚊感染人類。目前茲卡病毒的防治多利用噴灑殺蟲劑控制病媒蚊數量作為主要降低病毒傳播的方式，並無有效之疫苗及藥物可供預防及治療。而針對突變率較高之RNA病毒設計藥物也易有抗藥性的產生，因此積極開發新穎替代性策略是首要之務。過去的文獻指出，茲卡病毒的非結構性蛋白 (nonstructural proteins, NSs) 會參與病毒自身的複製與組裝，並透過活化螺旋酶 (helicase) 與蛋白酶 (protease) 進行病毒蛋白的修飾。而在哺乳動物及昆蟲的模式研究中，宿主細胞的熱休克蛋白90 (Heat shock protein 90, Hsp90) 不僅會與茲卡病毒NS3蛋白有交互作用，當Hsp90被降解，也會使病毒複製能力下降。因此本研究將利用埃及斑蚊為研究模式，探討病媒蚊體內Hsp90與茲卡病毒NS3作為抑制病毒複製標的蛋白的可能性。從初步的實驗結果中，我們發現Hsp90與NS3不僅有形成複合物的現象，且Hsp90的表現受到抑制時，也會影響茲卡病毒的感染率。此外我們利用病毒蛋白抑制劑 (Hydroxychloroquine) 抑制NS3被後會影響Hsp90蛋白的表現。因此，我們推測茲卡病毒可能透過NS3蛋白切割的方式，改變宿主體內Hsp90表現，藉此進行調控病毒複製與增殖的能力。我們預期透過抑制Hsp90能干擾NS3發揮正常功能，因此降低病毒數量及感染率。未來我們也會經由調控Hsp90的表現，更進一步去了解茲卡病毒與埃及斑蚊體內蛋白間調控的分子機制，期許能為研發抗病毒藥物提供一個可能的方向。

關鍵字

茲卡病毒 ； 埃及斑蚊 ； 非結構性蛋白3 ； 熱休克蛋白90 ； 蟲媒疾病

並列摘要

The mosquito is the main vector of several important arthropod-borne diseases, such as malaria, filariasis, Japanese encephalitis, dengue fever, chikungunya and Zika. These diseases are transmitted from human to human by different mosquito vectors. However, no effective vaccine and medication are available for Zika virus infection until now. Currently, vector control through insecticide treatment become the main approach to reduce the transmission of Zika virus. However, the fast modification on RNA viral genome might neutralize the effect of inhibition. Therefore, development of alternative strategies for mosquito-borne disease control is urgently required. Previous reports indicated that ZIKV nonstructural proteins (NSs) participated in the viral replication and protein assembly, whereas the viral protein processing was mediated by non-structure protein 3 (NS3) through helicase and protease activity. In addition, NS3 has been shown to interact with heat shock protein 90 (Hsp90) in mammalian model. When hsp90 be silenced in insect cell, the virus replication be suppressed. Our preliminary results showed that Hsp90 interacted with NS3, and viral infectivity was reduced by inhibition of Hsp90 through reverse genetic approach. We also showed that inhibition of NS3 by hydroxychloroquine resulted in the inhibition of Hsp90 expression. We hypothesize that NS3 might play important role of modulating Hsp90 function through its protease activity. In the future, we will further investigate the detail mechanism underlying the regulation between ZIKV protein and host heat shock proteins. Information gathered in this study will pave the way toward the drug development by using molecular engineering approaches.

並列關鍵字

Aedes aegypti ； zika virus ； NS3 ； Hsp90 ； arthropod-borne diseases

參考文獻

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