microRNA profiles and functions in mosquitoes

Mosquitoes are incriminated as vectors for many crippling diseases, including malaria, West Nile fever, Dengue fever, and other neglected tropical diseases (NTDs). microRNAs (miRNAs) can interact with multiple target genes to elicit biological functions in the mosquitoes. However, characterization and function of individual miRNAs and their potential targets have not been fully determined to date. We conducted a systematic review of published literature following PRISMA guidelines. We summarize the information about miRNAs in mosquitoes to better understand their metabolism, development, and responses to microorganisms. Depending on the study, we found that miRNAs were dysregulated in a species-, sex-, stage-, and tissue/organ-specific manner. Aberrant miRNA expressions were observed in development, metabolism, host-pathogen interactions, and insecticide resistance. Of note, many miRNAs were down-regulated upon pathogen infection. The experimental studies have expanded the identification of miRNA target from the 3′ untranslated regions (UTRs) of mRNAs of mosquitoes to the 5′ UTRs of mRNAs of the virus. In addition, we discuss current trends in mosquito miRNA research and offer suggestions for future studies.
Author summary Millions of human infections are caused by mosquito-borne diseases, so understanding the molecular and genetic mechanisms that determine variability in transmission efficiency and insect susceptibility may assist with novel vector control strategies. Recently, microRNAs (miRNAs) have been studied as post-transcriptional regulators of gene expression in vertebrates, invertebrates, and viruses. Because interactions between vectors and parasites are the keys to malarial transmission dynamics, identifying miRNAs involved in the developmental cycles of the mosquito and interactions between the mosquito and pathogens that allow the survival, proliferation, and disease transmission may help with disease control. In this review, we summarize the research on mosquito miRNAs regarding their expression and function in various physiological and pathological processes, and explore future research in this area.