Mosquito extracellular vesicles in malaria parasite killing and immune priming

Malaria has had devastating impacts on human health and economic development throughout the world. Caused by Plasmodium parasites, the transmission of malaria requires the bite of an infected Anopheles mosquito. This essential requirement of the mosquito vector to spread disease also creates unique opportunities to interrupt malaria transmission, where the mosquito immune system is an important determinant of vector competence. For this reason, the mosquito immune system has garnered significant attention to better understand the immune mechanisms that limit malaria parasites, with the goal that this knowledge can be applied to strategies to interrupt the malaria life cycle in its intrinsic mosquito host. Towards this goal, considerable research efforts have increased our understanding of the mosquito immune system, yet despite these advances, the immune mechanisms that promote Plasmodium recognition and killing in the mosquito host remain poorly understood. Herein, we describe novel roles of mosquito extracellular vesicles (EVs) in mosquito immune function, providing evidence that mosquito EVs have essential roles in the complement-mediated recognition of Plasmodium ookinetes (Aim 1) and the activation/priming of mosquito immune cells (hemocytes) (Aim 2). Therefore, the overall objective of this application is to obtain a mechanistic understanding of EV function in the context of the mosquito immune system by defining the roles of EVs in malaria parasite killing and immune cell activation/priming. Our outlined experiments will examine the influence of distinct EV (exosome or microvesicle) biogenesis pathways, define the molecular contents of EVs, and perform single-cell experiments to respectively delineate the mechanisms by which EVs promote pathogen recognition and cellular immune function in mosquitoes. The expected outcomes of this proposal will provide fundamental new insights into the previously unexplored roles of EVs in pathogen recognition and immune cell activation in mosquitoes, such that our results will have broad impacts on the study of innate immunity and host-pathogen interactions across invertebrate systems that may inform novel strategies to manipulate mosquito vector competence. Project Number: 1R01AI182256-01A1 | Fiscal Year: 2025 | NIH Institute/Center: National Institute of Allergy and Infectious Diseases (NIAID) | Principal Investigator: Ryan Smith | Institution: IOWA STATE UNIVERSITY, AMES, IA | Award Amount: $648,924 | Activity Code: R01 | Study Section: Transmission of Vector-Borne and Zoonotic Diseases Study Section [TVZ] View on NIH RePORTER: https://reporter.nih.gov/project-details/1R01AI18225601A1