Aedes aegypti Immune Response and Its Potential Impact on Dengue Virus Transmission

Mosquito CYP4C21 knockout reduces dengue virus and Zika virus replication in Aedes aegypti cells

Aedes aegypti (Ae. aegypti) is a major vector of dengue virus (DENV) and Zika virus (ZIKV). Understanding the complex interaction mechanisms between mosquito vectors and arboviruses is essential to interrupt virus transmission. This study constructed CYP4C21 knockout (KO) Aag2 cells (Ae. aegypti cells) and confirmed that CYP4C21 KO reduced DENV2 and ZIKV copies in Aag2 cells, which suggests that CYP4C21 may play an important role in mosquito infection with arboviruses. Furthermore, it is the first report of the CYP4 family related to viral infection, which lays the foundation for exploring the role of the CYP4C21 in the interaction of Ae. aegypti and arbovirus and provides novel insights into the function of cytochrome family proteins.

N6-methyladenosine modification of the Aedes aegypti transcriptome and its alteration upon dengue virus infection in Aag2 cell line

The N⁶-methyladenosine (m⁶A) modification of RNA has been reported to affect viral infections. Studies have confirmed the role of m⁶A in replication of several vector-borne flaviviruses, including dengue virus (DENV), in mammalian cells. Here, we explored the role of m⁶A in DENV replication in the mosquito Aedes aegypti Aag2 cell line. We first determined the presence of m⁶A on the RNAs from mosquito cells and using methylated RNA immunoprecipitation and sequencing (MeRIP-Seq) identified m⁶A modification of the mosquito transcriptome and those that changed upon DENV infection. Depletion of m⁶A methyltransferases and the m⁶A binding protein YTHDF3 RNAs decreased the replication of DENV. In particular, we found that the Ae. aegypti ubiquitin carrier protein 9 (Ubc9) is m⁶A modified and its expression increases after DENV infection. Silencing of the gene and ectopic expression of Ubc9 led to reduced and increased DENV replication, respectively. The abundance of Ubc9 mRNA and its stability were reduced with the inhibition of m⁶A modification, implying that m⁶A modification of Ubc9 might enhance expression of the gene. We also show that the genome of DENV is m⁶A modified at five sites in mosquito cells. Altogether, this work reveals the involvement of m⁶A modification in Ae. aegypti-DENV interaction.

Analysis of m⁶A RNA modifications in the mosquito transcriptome and their changes upon dengue virus infection provides insight into the role of epigenetics in regulating viral replication in mosquitoes.

Production, Transmission, Pathogenesis, and Control of Dengue Virus: A Literature-Based Undivided Perspective

Dengue remains one of the most serious and widespread mosquito-borne viral infections in human beings, with serious health problems or even death. About 50 to 100 million people are newly infected annually, with almost 2.5 billion people living at risk and resulting in 20,000 deaths. Dengue virus infection is especially transmitted through bites of Aedes mosquitos, hugely spread in tropical and subtropical environments, mostly found in urban and semiurban areas. Unfortunately, there is no particular therapeutic approach, but prevention, adequate consciousness, detection at earlier stage of viral infection, and appropriate medical care can lower the fatality rates. This review offers a comprehensive view of production, transmission, pathogenesis, and control measures of the dengue virus and its vectors.