Novel insights into a well-studied steroid hormone: the impacts of 20-hydroxyecdysone (20E) on mosquito immunity.

Monday, February 3, 2020 - 4:10pm
Event Type: 

Rebekah Reynolds, Iowa State University, Department of Entomology

Ph.D. defense seminar.

Abstract. Blood-feeding is an integral behavior of mosquitoes to acquire nutritional resources for reproduction. This requirement also enables mosquitoes to serve as efficient vectors of mosquito-borne diseases, most notably malaria. Recent studies suggest that mosquito immunity is stimulated following a blood meal, independent of infection status. Since blood-feeding results in the increased production of the hormone 20-hydroxyecdysone (20E), I hypothesized that 20E may play an important role in priming the immune response for pathogen challenge. In this study, I examined the immunological effects of priming in Anopheles gambiae with 20E prior to pathogen infection, demonstrating a significant reduction in bacteria and Plasmodium berghei survival in the mosquito host. RNA-seq analysis following 20E treatment identified several known 20E-regulated genes, and several immunological genes with previously reported function in anti-pathogen defense. These immunological genes included the anti-microbial peptide cecropin 3, which I confirm as an antagonist of bacteria and Plasmodium in An. gambiae, suggesting that these responses are under temporal regulation. Together, my data demonstrate that 20E influences cellular immune function and anti-pathogen immunity following mosquito blood-feeding, emphasizing the importance of hormones in the regulation of mosquito innate immune function.