PROJECT SUMMARY Over-nutrition with calorically dense diets high in fat (high fat diets, HFD) during adolescence may result in long-lasting changes in mechanisms regulating adult physiology. These changes may be further influenced by adult alcohol (EtOH) intake leading to increased risk of metabolic disorders, such as insulin and glucose dysregulation typically seen in Type II Diabetes. Additionally, over-nutrition with HFD and chronic EtOH intake are both known to influence hypothalamic neuroimmune function; however, the mechanisms of this interaction are not yet known. The overarching hypothesis of this project is that over-nutrition during adolescence promotes long-lasting perturbations in hypothalamic neuroimmune and insulin signaling leading to enhancement of EtOH-induced metabolic disruptions during adulthood. In Aim 1, researchers will utilize a combination of molecular and whole-animal physiology techniques to test the hypothesis that hypothalamic neuroimmune activity regulates the interaction of adolescent over-nutrition and adult EtOH exposure on whole-body insulin and glucose homeostasis. This aim will also determine if reducing neuroimmune activity during adolescent HFD exposure will result in a normalization of heightened hypothalamic neuroinflammation in adulthood. Aim 2 will test the hypothesis that hypothalamic insulin receptor function is a target of adolescent over-nutrition and adult EtOH interactions on metabolic function. This aim will directly assess hypothalamic insulin receptor function of mice by injecting insulin in the mediobasal hypothalamus and measuring insulin receptor phosphorylation and activity of downstream signaling cascades by Western blot analysis. This Aim will also further determine if inhibiting expression of protein-tyrosine phosphatase 1B, a known negative regulator of insulin receptor function that may be induced by neuroimmune activity, will improve metabolic function in these mice. Collectively, these findings will provide a comprehensive examination of the central mechanisms mediating the interaction of over-nutrition in adolescence with adult EtOH on peripheral metabolic function. Additionally, these studies will determine if hypothalamic neuroimmune and insulin receptor signaling may provide a novel target set to normalize this interaction.