Uncovering the Sensory Mechanisms of Blood Detection by Mosquitoes Using Innovative Genetic Approaches - PROJECT SUMMARY/ABSTRACT Vector mosquitoes, such as Aedes aegypti, drink human blood to nourish their developing eggs, transmitting devastating human diseases that result in over half a million annual deaths in the process. A comprehensive understanding of the cellular and molecular mechanisms that underlie mosquito blood-feeding behaviors is critical for identifying new strategies to control mosquito populations and mitigate disease transmission. To drink blood, a mosquito inserts a flexible needle-like structure called the labrum into the host’s skin to probe for blood vessels. Although it is clear that different groups of sensory neurons in the tip of the labrum respond to phagostimulant compounds like ATP and other blood components, the molecular receptors mosquitoes use to detect blood are unknown. The sensory processing and behavioral impact of individual classes of labral sensory neurons are also unclear. Gene editing technologies like CRIPSR/Cas9 are powerful tools for probing gene function. However, these techniques remain time consuming and laborious to implement in non-standard genetic model systems, making it a high-risk endeavor to study neofunctionalized or potentially species- specific genes involved in blood detection and other specialized mosquito abilities and behaviors. This project seeks to combine emerging technologies for single-nuclei RNA sequencing with my recently-developed high- throughput genetic analysis approaches to perform a deep mechanistic analysis of the mosquito blood- detection system. We will characterize the diversity of sensory neurons present in the labrum, gaining genetic access to each cell type in order to characterize the anatomical location, functional sensitivity, and behavioral impact of each class. Our high-resolution transcriptomics data will be merged with our new higher-throughput screening approaches to facilitate rapid, unbiased testing of candidate molecular receptors that control blood feeding. Though the gustatory system represents one of the most poorly understood mosquito sensory systems, cutting-edge techniques and recent discoveries in mosquitoes have set the stage for a research program on contact chemosensation that is exciting and feasible. This project is poised to open the labral chemosensory system to molecular study and transform it into an accessible model of mosquito taste. This award will be the first to fully map the inputs to the neural circuits for blood feeding in Ae. aegypti while examining the functional significance of each cell type and their underlying molecular mechanisms. Finally, the approach developed here will provide a blueprint and genetic tools that can be readily ported to facilitate future molecular discovery efforts aimed at addressing other pressing questions in mosquito biology.
