SUMMARY This Cell and Tissue Imaging and Analysis Core seeks provides a centralized and integrated resource for in situ proteomic analysis and imaging of the cellular and antigenic bioarchitecture of skin stem cells as a function of chronologic age and in the context of age-related deficiency in wound healing. It also provides translational validation through comparative examination of experimental murine and human skin selected as matched pairs by expert dermatopathologists to ensure cross-relevance. The Core thus combines highly skilled professional dermatopathology analysis and cutting-edge multiplex imaging technologies that permit sequential assessment of how cells and molecules behave in healing wounds, and how this behavior is compromised in the setting of age-related skin stem cell depletion/dysfunction. Specific Aim 1 provides PPG investigators with conventional histology of formalin-fixed, paraffin-embedded (FFPE) biospecimens, multiplex labeling for 3-4 epitopes, image quantification, and a variety of optional specialized technologies on an as-needed basis. This aim is essential to assess the cellular constituents and efficiency of wound healing responses in the context of various experimental models proposed in Projects 1-3 and in a manner that permits comparisons across projects. It also provides key data that will interface with the Bioinformatics Core (Core B), and assists in developing strategies to enhance wound healing through understanding potential utility of targeted therapeutic approaches directed at defective stem cell-driven repair pathways. Importantly, it offers standardized and uniform expertise and experience not available through simultaneous use of multiple institutional pathology resources. Specific Aim 2 takes multiplex labeling to the level of high-resolution, highly-plexed imaging, whereby cellular and proteomic intricacies can for the first time be visually unraveled at the level of 20 or more simultaneously identifiable antibody probes. This approach leverages in-house technology involving NanoZoomer scanning technology and QuPath data analysis in order to provide state-of-the art quantitative and spatial analysis of multiple epitopes expressed in situ by cells and their microenvironments relevant to skin aging and stem cell involvement in the wound healing process. It is fortified by collaborative interactions with Dr. Peter Sorger and application of related CyCIF labeling technology, as well as the availability of GeoMx technology for digital spatial proteomic and genomic profiling. Aim 3 provides an extensive human skin biobank whereby data generated by Core analyses of murine models may be readily compared and contrasted with relevant age-matched and co-morbidity-controlled wound healing responses in the human integument, as well as accessing and prospectively accumulating a wealth of relevant biospecimens for PPG analyses. Core C thus provides an essential, centralized, and highly integrated analytical com...