轉錄活化因子3在登革病毒複製中所扮演的角色

登革病毒(dengue virus)分為四種血清型 (type I、II、III、IV)，而感染不同血清型的登革病毒，會導致登革出血熱和登革熱休克綜合症，這是高死亡率的主要原因。迄今為止，也未有治療藥物及有效疫苗可以預防，故研究抗登革病毒藥物標靶為首要之急。根據次世代定序結果，觀察到登革病毒感染提升轉錄活化因子 3(Activating transcription factor 3, ATF3)之 mRNA 生成量。過去研究報導 ATF3 對 IFN-β的調節機制對於免疫反應非常重要，由於至今登革病毒躲避宿主先天免疫反應機轉仍尚未研究透徹，故本研究為進一步證實登革病毒複製與 ATF3 的關係，在登革病毒感染下，以 ATF3 shRNA (small-hairpin RNA; shATF3) 靜默 ATF3 基因的表現，發現能有效抑制登革病毒複製。進一步發現靜默 ATF3 會誘導干擾素(interferon)的生成，接著再使其下游 STAT1 和 STA2 的磷酸化，進而介導下游的抗病毒基因的表現（包括 OAS1，OAS2，OAS3 和 PKR），達到抗登革病毒之效果。使用活體小鼠動物實驗分析，發現攜帶 ATF3 shRNA 的腺病毒(Adenovirus-ATF3 shRNA) 可以保護 ICR 小鼠免於危及生命的登革病毒感染並減少登革病毒的子代複製。總體來說，我們的研究結果提供了一種新的抗病毒標靶基因，通過負調控 ATF3 基因表達及其調控之下游路徑來抑制登革病毒複製。

關鍵字

轉錄活化因子3 ；登革病毒；干擾素

並列摘要

Dengue virus is divided into four serotypes (type I, II, III, IV). Infection of more than one serotype of dengue virus highly corresponds to dengue shock syndrome and dengue hemorrhagic fever, which are the leading causes of high mortality. So far, there are no therapeutic drugs and effective vaccines that can prevent it. Therefore, research on anti-dengue virus drug targets is the first priority. According to the results of Next Generation Sequencing, it was observed that dengue virus infection increased Activating transcription factor 3 (ATF3) mRNA production. Past studies have reported that the regulatory mechanism of ATF3 on IFN-β is very important for the immune response. As the mechanism of dengue virus avoiding the host of innate immune response has not yet been thoroughly studied. This study aims to further confirm the relationship between dengue virus replication and ATF3. Under dengue virus infection, the expression of silent ATF3 gene with ATF3 shRNA (small-hairpin RNA; shATF3) was found to effectively inhibit dengue virus replication. We further found that silent ATF3 induces the production of interferon, and then phosphorylates downstream STAT1 and STA2, which in turn mediates the performance of downstream antiviral genes (including OAS1, OAS2, OAS3 and PKR), and achieves anti-dengue virus effect. In vivo animal experiment analysis found that adenovirus carrying ATF3 shRNA (Adenovirus-ATF3 shRNA) can protect ICR mice from life-threatening dengue virus infection and reduce dengue virus progeny replication. As a whole, our research results provide a new antiviral target gene that inhibits dengue virus replication by negatively regulating the expression of ATF3 gene and its downstream pathways.