Abstract
BackgroundThe midgut is the first barrier to dengue virus (DENV) infections of mosquitoes and therefore is a major bottleneck for the subsequent development of vector competence. However, the molecular mechanisms responsible for this barrier are unknown.ResultsWe constructed three small RNA libraries from the midguts of adult Aedes albopictus females that had been fed on either sugar solution, an uninfected blood meal, or a blood meal infected with DENV-2, and112 conserved microRNAs represented by 173 miRNA sequences were identified, with 34 novel microRNAs predicted by Mireap, RNAfold and Sfold software. In addition, the expression of aal-miR-1174, aal-miR-2951 and aal-miR-956 was confirmed via stem-loop quantitative real-time PCR (qRT-PCR). Compared with microRNA expression profiles of mosquitoes that had ingested a regular blood meal, 43 microRNAs were upregulated and 4were downregulated in mosquitoes that had ingested a DENV-2-infected blood meal. Among the differentially expressed microRNAs, miR-1767, miR-276-3p, miR-4448 and miR-4728-5p were verified via stem-loop qRT-PCR.ConclusionsAnalyses indicated that the changing patterns in miRNA expression during DENV-2 infection were significant and varied at different time points post infection. Most miRNA were upregulated at 24 h but were downregulated at 48 h post DENV-2 intake. The aal-miR-4728-5p was chosen for an in vitro transient transfection assay, and the results show that this miRNA enhances DENV replication in C6/36 cells. This study provides the first information on microRNAs expressed in the midgut of Ae. albopictus and describes species-specific changes in their expression levels following infection by DENV-2.
Highlights
The midgut is the first barrier to dengue virus (DENV) infections of mosquitoes and is a major bottleneck for the subsequent development of vector competence
Group C was fed on sugar solutiononly; Group B was fed on uninfected blood meal; and Group D was fed on an artificial Dengue virus 2 (DENV-2) blood meal
Overview of the dataset To identify miRNAs expressed in the midgut of Ae. albopictus and to explore their functions following the ingestion of DENV-infected blood, three small libraries of Ae. albopictus midgut RNAs were constructed, one from mosquitoes that had been fed on sugar solution (C), one from those that had been fed on uninfected blood (B) and one from those that had been fed on blood
Summary
The midgut is the first barrier to dengue virus (DENV) infections of mosquitoes and is a major bottleneck for the subsequent development of vector competence. The molecular mechanisms underlying the specific binding between viral pathogens and midgut epithelial cells that regulate viral replication are still unclear. This in turn has been an obstacle to research on the molecular mechanisms responsible for the susceptibility of mosquito vectors to DENV. Understanding the molecular mechanisms underlying these differences in vector competence is important in assessing the risks posed by any particular arbovirus, assessing mosquito vector combinations and indeveloping novel strategies to mitigate or block the transmission of mosquito-borne arboviruses
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