ABSTRACT Adverse childhood experiences (ACEs) result in enduring changes to the body’s endocrine, metabolic, immune, and nervous systems that contribute to dysregulated stress responses and health-harming coping behaviors (smoking, alcohol, and illicit substance abuse, overeating and obesity), ultimately leading to the mental and physical illnesses observed in large-scale epidemiological studies of ACEs (e.g., cardiovascular disease, autoimmune diseases, depression, and suicide). As a result, achieving CIRCA’s Phase 2 aims will require building a robust physical infrastructure and intellectual support for the collection, storage, analysis, and interpretation of data from across diverse biological systems. The mission of the CIRCA Biological Systems Core is thus to support phase 2 CIRCA investigators as they incorporate into their projects a broad range of biological research methods, including genetics and gene expression (e.g., sequencing and RT-PCR), epigenetics (e.g., pyrosequencing), protein measurements (e.g., MSD and ELISAs), immunophenotyping (e.g., flow cytometry and ELISPOT), brain structural and functional imaging (e.g., MRI, fMRI, and functional near- infrared spectroscopy), and psychophysiology (e.g., electromyography, heart rate variability, etc.), as well as remote biosensors and sample collection technologies (e.g., Oura rings, Cyto-Chex cell stabilization tubes, etc.). The first Aim of the phase 2 CIRCA Biological Systems Core will be to provide Research Project Leaders (RPLs) with access to the laboratory space to collect the biosamples and biological data required to complete their project goals, the equipment to store and analyze those samples and data, and the domain expertise and training necessary for valid interpretation and scientific inference from the analytical results. The second Aim of the Biological Systems Core will be to provide phase 2 CIRCA RPLs and pilot project scientists with common biological data elements, a biosample repository, and clinical registry that will provide training opportunities and pilot data for papers and grant proposals by faculty across the OSU system focused on advancing adversity and resilience science. The Biological Systems Core will standardize across all participants in phase 2 CIRCA projects the collection, storage, and analysis of common biological data elements related to the endocrine, metabolic, immune, and neural consequences of ACEs. The resulting databank of ACEs-related biological data in a large number of participants will be an invaluable resource to all current and future phase 2 CIRCA scientists. In addition to common biological data elements, the Core will create a long-term repository of biological samples that will be available to future CIRCA pilot-project scientists with novel hypotheses about the biological consequences of ACEs. The Core will also contribute to the creation of a clinical registry that will marry clinical and biosample data with assessments of ACEs a...