Project Summary/Abstract The Cellular Aging Core (Core C) will isolate and distribute bone marrow-derived mesenchymal stem/progenitor cells (MSCs) from C57BL/6 mice, a common aging model for the Program Project, to the investigators of the individual projects. Core C will also isolate and provide MSCs and myoblasts from project-specific genetically altered (transgenic or knockout) mouse models. Furthermore, Core C will provide services for hypoxic cell culture, multiplex cytokine assay and Seahorse mitochondrial function assays, as well as Cre-expressing adenovirus production and infection. A key component essential to the success of the proposed Program Project is the availability of MSCs because all projects require these cells. Thus, a centralized Core facility for the production of quality cells, as well as providing standardized assays, are essential to the success of each individual project, and the Program as a whole. This Core will benefit the research efforts of individual investigator by reducing costs, providing quality control for study procedures, and enhancing collaborations among multiple disciplines to achieve greater scientific gain through an integrated approach. In addition, production and distribution of cells and service from a centralized facility will ensure that all studies start with cells of the same lineages and background. By serving as a centralized resource for musculoskeletal progenitor cells and various cellular assays, Core C will facilitate the collection of reproducible, accurate data concerning the role of tryptophan (Trp) and kynurenine (Kyn) and their metabolites on bone and muscle in health and disease.