| Summary: | 碩士 === 國立陽明大學 === 微生物及免疫學研究所 === 102 === Dengue fever (DF) is presently one of the most important aborviral disease that affects human health. The major vector of DF is Aedes aegypti and Aedes albopictus is the secondary vector. Results of the previous studies demonstrated that infection of dengue 2 virus (DENV2) in both mammalian cells and Ae. aegypti induced autophagy machinery and autophagy enhanced the replication of DENV2. In mammalian cells, autophagy is induced by mTOR-dependent and mTOR-independent autophagy induction pathways. However, which autophagy induction pathway participates in DENV2-infected Ae. aegypti remains unknown. In the present study, we used double-stranded RNA (dsRNA) silencing analysis and chemicals to elucidate the autophagy induction pathway in DENV-infected mosquitoes. It was found the induction of autophagy by silencing of IMPase, an important factor in mTOR-independent autophagy induction pathway, did not significantly affect the replication of DENV2 in Ae. aegypti. On the other hand, the induction of autophagy by feeding the mosquitoes with 10% sucrose containing 1000 nM A-769662 to activate AMPK, an important factor in AMPK/TSC/mTOR pathway, significantly enhanced the replication of DENV2 in Ae. aegypti. In addition, we also found the inhibition of autophagy by feeding mosquitoes with 10% sucrose containing 800nM SC-79 to activate Akt, an important factor in PI3KC1/Akt/TSC/mTOR autophagy induction pathway, did not significantly affect the replication of DENV. Bioinformatic analysis revealed that Ae. aegypti AAEL000608 could be the ortholog of FIP200, which is a mammalian ortholog of yeast Atg17. The expression of AAEL000608 was significantly enhanced in Ae. aegypti after the infection of DENV2. And knockdown of AAEL000608 significantly reduced the replication of DENV2 in Ae. aegypti. Our results also demonstrated knockdown of Atg9 significantly reduced the replication of DENV2 in Ae. aegypti In conclusion, our results indicated that autophagy was induced through AMPK/TSC/mTOR pathway in DENV2-infected Ae. aegypti. In addition, we also found both AAEL000608, which is the ortholog of FIP200, and Atg9 are essential components in autophagy induced by the infection of DENV2 in Ae. aegypti.
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