MicroRNA expression dynamics in Culicoides sonorensis biting midges following blood-feeding

Authors: MILLS, MARY - Medical University Of South Carolina; ROZO-LOPEZ, PAULA - University Of Tennessee; BRYANT, WILLIAM - Medical College Georgia; Drolet, Barbara

Submitted to: Insects
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/2/2023
Publication Date: 7/6/2023
Citation: Mills, M.K., Rozo-Lopez, P., Bryant, W.B., Drolet, B.S. 2023. MicroRNA expression dynamics in Culicoides sonorensis biting midges following blood-feeding. Insects. 14:611-625. https://doi.org/10.3390/insects14070611.
DOI: https://doi.org/10.3390/insects14070611

Interpretive Summary: Culicoides sonorensis are tiny insects that can transmit diseases to livestock, causing significant economic losses worldwide. In order to limit the spread of disease, it's important to understand how these insects function. Previous research has shown that small molecules called microRNAs (miRNAs) play an important role in insect biology, including the development of eggs and the immune system. MiRNAs control how genes are expressed in insects and can change in response to infections. However, little is known about the specific miRNAs present in Culicoides sonorensis. In this study, the researchers used a technique called small RNA-Seq to identify the miRNAs present in whole female insects and in their midgut tissues in response to blood feeding. They discovered 76 miRNAs in Culicoides sonorensis, including some that were similar to those found in other insects, as well as some unique miRNAs. They also found that certain miRNAs were more abundant in specific tissues, including tissues involved in digestion and reproduction. The researchers also looked at publicly available data to identify miRNAs that were associated with viral infections. This information could be used to develop new strategies to control disease transmission by Culicoides sonorensis. Overall, this study provides a foundation for future research into the role of miRNAs in Culicoides sonorensis biology and the transmission of diseases to livestock.

Technical Abstract: Culicoides sonorensis midges vector multiple livestock arboviruses, resulting in significant economic losses worldwide. Due to the tight association between virus transmission, blood feeding, and egg development, understanding midge physiology is paramount to limiting pathogen transmission. Previous studies have demonstrated the importance of small non-coding RNAs (ncRNAs), specifically microRNAs (miRNAs), in multiple aspects of vector physiology, such as egg development and immunology. These small ncRNAs regulate gene expression at the post-transcriptional level and display differential expression during pathogen infection. Due to the lack of annotated miRNAs in the biting midge and associated expression profiles, we used small RNA-Seq and miRDeep2 analyses to determine the Culicoides miRNAs in whole females and midgut tissues in response to blood feeding. Our analyses revealed 76 miRNAs within C. sonorensis composed of 73 orthologous and three candidate novel miRNAs, as well as conserved miRNA clusters. miRNA conservation suggest an interesting evolutionary relationship between miRNA expression and hematophagy in the infraorder Culicomorpha. We also identified multiple blood meal-regulated and tissue-enriched miRNAs. Lastly, we further identified miRNAs with expression patterns associated with virus infection by probing publicly available datasets. Together, our data provides a foundation for future ncRNA work to untangle the dynamics of gene regulation associated with midge physiology and virus transmission.