Project Summary Alcoholic liver disease is a major clinical challenge because it is associated with severe complications like liver cirrhosis and alcoholic hepatitis, which carry a high mortality. Our understanding of the mechanisms underlying alcoholic liver disease is still evolving; however, previous research has identified cells critically involved in the liver's response to alcohol-induced injury, including myofibroblasts, macrophage subsets and oval cells, which are referred to as ductular reaction in humans. Because of their unique and important functions in alcoholic liver disease, efficient and specific gene delivery to these cell types would have many applications in research and therapy of alcoholic liver disease, particularly if nonintegrating nontoxic adenoassociated viral (AAV) vectors could be used. The research scope of the proposed diversity supplement is the same as that of the parent R01 AA026578, that is, to establish efficient and specific transduction of myofibroblasts, macrophage subsets and oval cells with AAV vectors in mouse models of alcoholic liver disease. The supplement is complementary to R01 AA026578 because it uses a different approach: First, instead of selecting over a million newly generated capsids with unknown tropism in the cell types of interest as done in R01 AA026578, the supplement will identify among almost two hundred capsids previously successfully tested in other settings, including in the liver at the organ but not at the cell level, those that transduce the cell types of interest. Thus, the supplement maximizes the likelihood of successful targeting of the cell types of interest by including promising existing candidate capsids in the analysis. Second, because of the smaller scale of the candidate capsid cohort, the supplement will be able to employ single-cell RNA sequencing as an efficient method to identify capsids affording functional transduction of the cell types of interest. The use of essential and innovative technologies in the supplement, including mouse models of alcoholic liver disease, precise isolation of the principal liver cell populations by FACS, AAV production and single-cell RNA sequencing in combination with formal training in bioinformatic analysis of sequencing data provides a profound state-of-the-art research training opportunity that will serve as the foundation for the trainee's career plan of becoming a physician- scientist. As an essential part of the research training, the trainee will be able to practice and refine his newfound research skills in close collaboration with experienced junior scientists. A milestone-based structured mentoring plan developed by the experienced PI will further equip the trainee with the critical thinking, creativity, resourcefulness and oral and written presentations skills needed to succeed as an independent researcher and make impactful contributions to research and medicine.