MicroRNA levels are modulated in Aedes aegypti after exposure to Dengue‐2

Abstract

To define microRNA (miRNA) involvement during arbovirus infection of Aedes aegypti, we mined deep sequencing libraries of Dengue type 2 (DENV2) -exposed mosquitoes. Three biological replicates for each timepoint (2, 4, and 9 days post-exposure (dpe)) and treatment group allowed us to remove outliers associated with sample-to-sample variability. Using edgeR (R Bioconductor), designed for use with replicate deep sequencing data, we determined the log fold-change (logFC) of miRNA levels (18–23 nts). The number of significantly modulated miRNAs increased from 5 or fewer at 2 and 4 dpe to 23 unique miRNAs by 9 dpe. Putative miRNA targets were predicted by aligning miRNAs to the transcriptome, and the list was reduced to include the intersection of hits found using the Miranda, PITA, and TargetScan algorithms. To further reduce false positives, putative targets were validated by cross-checking them to mRNAs reported in recent DENV2 host response transcriptome reports; 4076 targets were identified. Of these, 464 gene targets have predicted miRNA binding sites in 3′UTRs. Context-specific target functional groups include proteins involved in transport, transcriptional regulation, mitochondrial function, chromatin modification and signal transduction processes known to be required for viral replication and dissemination. The miRNA response is placed in context with other vector host response studies by comparing the predicted targets to those of transcriptome studies. Together, these data are consistent with the hypothesis that profound and persistent changes to gene expression occur in DENV2-exposed mosquitoes.

Expression of Mosquito MicroRNA Aae-miR-2940-5p Is Downregulated in Response to West Nile Virus Infection To Restrict Viral Replication

“…A number of differentially expressed miRNAs have been identified in DENV-infected A. aegypti cells (48). Targets of these miRNAs include genes responsible for transcription regulation, mitochondrial function, intracellular transport, chromatin modification, and signal transduction that are known to be required for viral replication and dissemination (48). In the present study, we identified a novel mechanism of antiviral response in insects that is dependent on a host miRNA.…”

“…Specifically, WNV infection of human cells was shown to induce the expression of miRNA hsa-miR-154, which downregulates the expression of antiapoptotic proteins CCCTCbinding factor and EGFR-coamplified and overexpressed protein, thus inducing apoptosis in infected cells (30). A number of differentially expressed miRNAs have been identified in DENV-infected A. aegypti cells (48). Targets of these miRNAs include genes responsible for transcription regulation, mitochondrial function, intracellular transport, chromatin modification, and signal transduction that are known to be required for viral replication and dissemination (48).…”

“…On the other hand, it is intriguing that aae-miR-2940 has different effects on replication of different flaviviruses. However, taking into account that no changes in aae-miR-2940 expression were found in DENV-infected mosquito cells examined using a deep-sequencing approach (48), it is likely that aae-miR-2940 is not involved in DENV-mosquito host interactions in the absence of coinfection with Wolbachia. Therefore, the downregulation of aae-miR-2940 expression observed in our experiments is likely to be attributed to a specific antiviral response against WNV.…”

Human MicroRNA miR-532-5p Exhibits Antiviral Activity against West Nile Virus via Suppression of Host Genes SESTD1 and TAB3 Required for Virus Replication

“…Dengue virus (DENV) infection was shown to alter the expression of numerous miRNAs in mosquito (18) and human (19) cells. In particular, DENV strongly induced the expression of miR-146a in human monocytes, with significant benefit to virus replication (20).…”

Regulatory role of cellular and viral microRNAs in insect–virus interactions

“…Differential expression of host miRNAs has been shown for baculoviruses [28,29,30 ], an ascovirus [31], a cytoplasmic polyhedrosis virus [32], West Nile virus (WNV) [33 ], chikungunya virus [42] and dengue virus (DENV) [34]. These changes, detected by microarray or deep sequencing analyses, could be either due to host response to viral infection or host manipulation by the virus, including virusencoded miRNAs (see below).…”