Microorganisms located in the gut interact and may influence the function of neurochemical systems that alter behavior in their hosts. The gut microbiota may communicate with the brain to ensure that food intake and energy expenditure are adequately maintained by influencing foraging activity/behavior and food choices. It is possible that the relationship between the gut, its microbial community and the brain is bidirectional, and one possible neuropeptide system in the brain that may contribute to this communication is the orexin system. The orexin system has been associated with many processes, such as activity and feeding. The goal of this project is to investigate how gut microbiota influence host fitness after foraging and food choice, orexin system antagonism, and disturbances of the gut microbiota (via long-term exposure to probiotics or antibiotics). This project will use a rodent behavioral model to identify males and females with high or low-preference for a particular diet and then use pharmacological manipulations of the orexin system to analyze shifts in structure and diversity of microbial communities as analyzed from fecal and colon samples. In addition, probiotic and antibiotic administrations will be employed to examine how these regimens control feeding behavior, affect orexin neuronal activity, and microbial structure and diversity. These data will enhance society's understanding of how the brain communicates with microbial communities and how this interaction can impact fundamental food seeking behaviors that are required for survival and maintain fundamental homeostatic processes involved in maintenance of energy balance.
Delineating the relationship between the gastrointestinal system, its microbial community, and the brain is critical to our understanding of the bidirectional communication of the microbiota-gut-brain axis and signaling pathways that drive foraging behavior and food choice. The goal of this project is to investigate the ability of gut microbiota to influence foraging and food choice and determine whether neuropeptide regulation (via orexins) plays a role in microbial fitness. Orexins are neuropeptides that regulate energy balance, by increasing food intake and contribute to increased energy expenditure. Food choice testing and competitive foraging tests will be used to assess the impact of varying energy-dense diets and sex on feeding behavior, host fitness, orexin neuronal activity, and microbiome dynamics. It will also be determined whether microbiome alterations via a panel of probiotics and antibiotics impacts behavioral, physiological, and/or neurochemical activity. It is hypothesized that gut microbiota participate in gut-brain signaling by influencing foraging and food choice and that the orexin system contributes to the mechanisms that drive these behaviors. In addition to providing valuable data for the general populace about dietary choices and their impacts across multiple scales this work will provide research and educational opportunities for students at an HBCU and help in developing stronger educational programs at the investigator's home university.
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.
