Aalpi18529 regulates vitellogenesis of Aedes albopictus via the Gadd45a-mediated JNK-dependent nurse cell apoptosis pathway {RNA-seq]

Aedes albopictus shows a rapid global expansion and dramatic vectorial capacity for various arboviruses. Mosquitoes display distinct sexual dimorphisms,only adult females consume blood meals to complete ovarian follicle development. Therefore, cyclic reproduction in female mosquitoes serves as a foundation for the transmission of numerous disease-causing pathogens. Aedes have an expansion of the piRNA biogenesis genes, indicated that piRNA may play multiple functional roles in mosquitoes. Although the antiviral function of piRNA pathway in mosquitoes has been extensively studied, the role of piRNAs in mosquito reproduction remain to be further understood. In the present study, we first profiled the characteristics of sex-biased piRNAs in adult Ae.albopictus. Then, we identified a female biased piRNA (Aalpi18529) in adult females, that was highly expressed in ovaries at blood feeding-dependent termination, and depended on PIWI5 and ago3 mediated biogenesis. Aalpi18529 overexpression suppressed ovarian development, and reduced fertility and fecundity in adult females post-bloodmeal. Furthermore, we demonstrated that Aalpi18529 can effectively repress its direct target, growth arrest and DNA-damage-inducible protein 45a (GADD45A), and eventually regulates ovarian development via the Gadd45a-mediated JNK-dependent nurse cell apoptosis pathway. Our study is the first to report an endogenous piRNA, which trigger silencing of an important protein-coding gene by posttranscriptional regulation in mosquitoes, expanding our current understanding of the important and multiple roles of piRNAs in biological processes in Ae. albopictus. Overall design: To better understand the effect of Aalpi-18529 on ovarian development post blood meal, we performed genome-wide transcriptional profiling analysis of ovaries that were treated with Aalpi-18529 mimics.