** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** IN A SERIES OF STUDIES WE HAVE DEMONSTRATED THAT MICE FED A DIET FORMULATED TO MIMIC AVERAGE AMERICAN MACRO AND MICRONUTRIENT INTAKES (TOTAL WESTERN DIET, TWD) HAVE INCREASED INFLAMMATORY GENE EXPRESSION, GUT INFLAMMATION, COLITIS SEVERITY, AND CHANGES TO THE GUT MICROBIOME COMPARED TO MICE FED HEALTHY CONTROL DIETS. RECENTLY, OTHERS HAVE SHOWN THAT PSYCHOLOGICAL STRESS (PS) HAS SIMILAR DETRIMENTAL GUT HEALTH EFFECTS INCLUDING INCREASED INFLAMMATORY GENE EXPRESSION, DECREASED MUCIN THICKNESS, AND CHANGES TO THE GUT MICROBIOME AND METABOLOME. CONSIDERING THAT POOR DIET AND PS ARE COMMON IN CONTEMPORARY SOCIETY AND CAN OCCUR SIMULTANEOUSLY, WE HAVE A KEEN INTEREST IN DETERMINING INTERACTIONS BETWEEN DIET, PS, AND GUT HEALTH. THE WORK PROPOSED IN THIS SEED GRANT WOULD EXTEND OUR WELL-ESTABLISHED DIET/COLITIS MODEL TO INCLUDE ANOTHER ENVIRONMENTAL STRESSOR, PS. MOREOVER, WE PROPOSE TO USE RAMAN SPECTROSCOPY (RS) COUPLED WITH MACHINE LEARNING TO DEVELOP A NOVEL GUT INFLAMMATION MEASURE THAT WILL BE FASTER AND LESS EXPENSIVE THAN TRADITIONAL HISTOPATHOLOGY MEASURES. BASED ON OUR PREVIOUS STUDIES, WE HYPOTHESIZE THAT TWD-FED MICE SUBJECTED TO PS WILL HAVE INCREASED INFLAMMATORY GENE EXPRESSION, GUT INFLAMMATION, AND COLITIS DISEASE ACTIVITY RELATIVE TO MICE FED CONTROL DIETS. THIS NOVEL DATA WILL INCREASE OUR UNDERSTANDING OF HOW DIET AND PS INTERACT TO MODIFY GUT HEALTH. THE PROPOSAL ADDRESSES THE PROGRAM AREA, FOOD AND HUMAN HEALTH PRIORITY AREA (A1343) AND SPECIFICALLY ADDRESSES THE STATED PRIORITY: INVESTIGATE THE ROLE OF THE FOOD COMPONENTS OR CONTAMINANTS ON THE HUMAN GUT MICROBIOME AND ITS METABOLITES, AND THE SUBSEQUENT IMPACT ON HUMAN HEALTH.