PROJECT SUMMARY This is an application for a Research Supplement to Promote Diversity in Health-Related Research to support the graduate training of an outstanding Ph.D. student, Diego Ruiz, who meets multiple NIH criteria for an underrepresented minority. Diego has shown extensive commitment to a career in the biomedical sciences and has previous undergraduate research prior to starting his graduate studies at the University of New Mexico. His long-term career goal is to conduct environmental research while devoting substantial effort to encouraging others of underrepresented groups to consider careers in science. Doctoral training is the logical next step to achieving his career goal. Diego and I established a mentoring team to help guide his individual scientific development and position his for short-term success as a Ph.D. student that is competitive for NIH F31 award. A key part of Diego’s career development plan is successful completion of a research project that will result in two first-author publications and a submission of a F31 award. Diego’s research project is an outgrowth of my R01 (R01ES032037; funded through 2027). The purpose of the R01 seeks to bridge the gap in environmental health knowledge and provide insight into how MP pose a significant health risk to the general population as well as susceptible individuals. We have found the in vivo exposure of mice to MP results in intestinal cell lineage changes (as determined by gene expression) and can cross the intestinal barrier and transverse to other tissues in the body; however, there appears no signs of intestinal inflammation. These two findings suggest i) MP may influence intestinal stem cell differentiation, specifically, increasing enteroendocrine cells and ii) the epithelial barrier is sterilizing the MP before reaching the lamina propria. Addressing these findings is the overall goal of Diego’s project. His first aim involves performing single cell RNA sequencing and performing bioinformatics. Aim two will be examining the lysosomal response from a molecular and biochemical approach. Both aims require the use of intestinal organoids and co-mentor Dr. Julie In, an expert in organoid biology, will provide training in this area. These studies will yield important understanding on how microplastics can impact gut health. At the conclusion of his research-training period, Diego will be a well- trained cell biologist with extensive experience in designing and conducting research and in science communication.