Abstract
IntroductionIt is essential to determine the interactions between viruses and mosquitoes to diminish dengue viral transmission. These interactions constitute a very complex system of highly regulated pathways known as the innate immune system of the mosquito, which produces antimicrobial peptides that act as effector molecules against bacterial and fungal infections. There is less information about such effects on virus infections.ObjectiveTo determine the expression of two antimicrobial peptide genes, defensin A and cecropin A, in Aedes aegypti mosquitoes infected with DENV-1.Materials and methodsWe used the F1 generation of mosquitoes orally infected with DENV-1 and real-time PCR analysis to determine whether the defensin A and cecropin A genes played a role in controlling DENV-1 replication in Ae. aegypti. As a reference, we conducted similar experiments with the bacteria Escherichia coli.ResultsBasal levels of defensin A and cecropin A mRNA were expressed in uninfected mosquitoes at different times post-blood feeding. The infected mosquitoes experienced reduced expression of these mRNA by at least eightfold when compared to uninfected control mosquitoes at all times post-infection. In contrast with the behavior of DENV-1, results showed that bacterial infection produced up-regulation of defensin and cecropin genes; however, the induction of transcripts occurred at later times (15 days). Conclusion: DENV-1 virus inhibited the expression of defensin A and cecropin A genes in a wild Ae. aegypti population from Venezuela.
Highlights
It is essential to determine the interactions between viruses and mosquitoes to diminish dengue viral transmission
We found that the expression of defensin A and cecropin A genes, two antimicrobial peptide genes mediated by the toll pathway, was significantly reduced in Ae. aegypti mosquitoes infected with DENV-1 suggesting that the infection progresses by suppressing the toll pathway
We determined whether the DENV-1 was stable at early post-infection times (5 and 24 hours) and replicated at later ones (10 and 15 days) in the mosquitoes using RT-PCR amplification followed by agarose gel electrophoresis analysis of the products
Summary
It is essential to determine the interactions between viruses and mosquitoes to diminish dengue viral transmission. These interactions constitute a very complex system of highly regulated pathways known as the innate immune system of the mosquito, which produces antimicrobial peptides that act as effector molecules against bacterial and fungal infections. Objective: To determine the expression of two antimicrobial peptide genes, defensin A and cecropin A, in Aedes aegypti mosquitoes infected with DENV-1. Results: Basal levels of defensin A and cecropin A mRNA were expressed in uninfected mosquitoes at different times post-blood feeding. Conclusion: DENV-1 virus inhibited the expression of defensin A and cecropin A genes in a wild Ae. aegypti population from Venezuela
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