PROJECT SUMMARY: Cellular Imaging Core Advanced cellular microscopy is a powerful tool for biological research and has an important role to play in the study of disease pathogenesis, which may translate eventually to novel treatment approaches for rheumatic diseases. Imaging technology has evolved rapidly over the last decade leading to improvements in resolution, sensitivity and speed which have created fundamentally new opportunities for studying processes across many orders of magnitude and in real-time in living cells and animals. At the same time, the costs of increasingly sophisticated equipment are substantial and the expertise to efficiently use, maintain, and develop this equipment is not common in most labs. There is therefore a significant gap between the availability of these powerful tools and the ability of investigators to access and use them efficiently. The Cellular Imaging Core (CIC) was originally created in response to feedback from Washington University Rheumatic Diseases Research Resource-based Center (WU-RDRRC) members to leverage the significant institutional investment in the newly created Washington University Center for Cellular Imaging (WUCCI) and provide an integrated approach to investigate the structure and dynamic behavior of cells and tissues in rheumatic disease-related model systems. The overall objective of the core is to provide access to and technical support in using advanced cellular microscopy tools to accelerate the pace, expand the scope, and improve efficiency of rheumatic diseases research. The core services meet the unique requirements of numerous investigators over a wide range of basic and translational research, attracting new investigators into rheumatic diseases research areas. Importantly the users benefit from the in-depth technical expertise of the Core Director and technical staff in the time spent in consultation for experimental design and interpretation of data. During the past funding cycle, the core served 28 WU-RDRRC investigator research laboratories, who expensed $520,699 in core recharges, which represented approximately 12% of all WUCCI activity. Fourteen WU-RDRRC investigator laboratories received micro-grant funding through the WU- RDRRC Imaging Core Scholarship program, 5 of which were junior faculty members. Given the broad usage of core over the past funding cycle, and the establishment of new imaging technologies (e.g. cryoEM and lattice lightsheet), sample preparation services (e.g. tissue clearing), and analysis approaches (e.g. AI-based IHC and IF image analysis), it is anticipated that requests for CIC services will continue to be robust given the overwhelming need for advanced microscopic imaging and image analysis approaches, thus accelerating the research endeavors of WU-RDRRC members throughout the next funding cycle.