CAREER: Understanding the persistent effects of the food environment on taste sensation

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Life experiences like trauma and abuse can have lasting effects on the brain, altering the behavior of animals for a lifetime. This occurs because a memory of the event is written and persists beyond the environmental circumstances' change. These memories limit the range of possible behavioral responses to future stimuli and may lock animals into maladaptive patterns of behavior. How these memories are written, how they influence behaviors, and how they become etched in the brain has been hard to study. Here the investigators will implement a research and educational platform to understand the enduring effects of the dietary environment on the brain. Specifically, they will use the genetically tractable model organism Drosophila melanogaster (fruit fly) to study how high dietary sugar, which is prevalent in society, permanently changes taste sensation and feeding behavior. The broad impact goal is to develop an outreach platform to disseminate accurate and accessible knowledge on the lasting effects of environmental influences on the brain. The target audience of that platform are people of all ages and challenges traditional campus boundaries. Together, the intellectual and the broader impact this project have implications for the field of public health by uncovering and communicating the mechanisms through which the environment, and especially diet, has a lasting effect on brain and behavior. Diet composition alters the peripheral processing of sensory information, and this, in turn, influences food choice and food intake. The principal investigator recently showed that high dietary sugar decreases the responses of the sensory neurons to sweetness in D. melanogaster. Furthermore, the investigator established a causal link between changes in sweet sensation to the action of the Hexosamine Biosynthesis Pathway (HPB), a metabolic signaling pathway activated by high levels of sugar. Preliminary experiments show that the HPB requires the gene silencing activity of the Polycomb Repressive Complex 2 (PRC2) to decrease sweet taste, which provides a mechanism to link food environment and behavior. This project uncovers the molecular mechanisms through which PRC2 leads to persistent changes in the physiology of the sweet sensing cells by (1) determining the effect of PRC2 manipulations on the activity of the sweet sensing neurons; (2) establishing how PRC2 targets affect the physiology of the sensory neurons to decrease sweet taste function; and (3) identifying how sweet taste deficits persist beyond exposure to the high sugar environment. These aims are pursued using a combination of genetic, molecular, and behavioral approaches.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.