The incidence of obesity worldwide continues to escalate with the spread of the Western diet and with it there has been a corresponding increase in cardiovascular disease, diabetes, end-stage renal disease and other obesity-related disorders. Of all the causes for obesity, the predominant one seems to be choice - the choice to eat more and exercise less. One of the choices that has been linked with obesity has been the selection of a high fat, calorically dense diet. Despite much research on the link between fat intake and obesity, relatively little is known about the chemosensory mechanisms that underlie the taste of fat and how these mechanisms might contribute to dietary fat intake. Our previous research has identified differences in how the taste systems in obesity-prone and -resistant rodents respond to fatty acids, a cue for dietary fat, and how this was correlated to differences in gene expression and receptor function. Moreover, we have demonstrated that these chemosensory mechanisms are modulated by diet and the development of obesity. The revised proposal focuses on pursuing a more focused, single remaining specific aim that seek to explore how the gustatory response to fat is modulated by dietary experience. There is new and emerging data that argues to the plasticity of the peripheral taste system, yet our understanding of how the system changes in relation to experience is poor at best. Specifically, we will use an approach including a multidisciplinary approach to answer the following question: 1. Is the fatty acid transduction pathway modulated by diet? Our multidisciplinary approach analyzing genes through behavior will be used to test the hypothesis that fat receptor expression in taste cells is altered during high fat feeding in a manner that results in an increased responsiveness to fatty acids. Following high fat dietary regimens, molecular, cell-based and behavioral assays will be performed to measure changes in four primary receptive elements in the fatty acid signaling pathway, including CD36, GPR 120, GPR 84 and fatty acid-sensitive DRK channels. Our extensive preliminary data generated in the previous period would argue that these are the primary components of the pathway that underlies the ability of the gustatory system to recognize and respond to free fatty acids.
This project will identify how the gustatory mechanisms the body uses to recognize dietary fat are modulated by diet and the development of obesity. The contribution of the taste system to individual variability in fat intake and preference will be assessed. Understanding these mechanisms and their regulation may lead to the development of novel fat substitutes and help our understanding of how the intake of high fat diets may contribute to the epidemic of obesity.
