Architecture and interactions of Granzyme K+ CD8 T cells in inflamed synovium in rheumatoid arthritis

Project Summary/Abstract This proposal is a five-year research and training plan with a scientific focus on interactions between CD8 T cells and fibroblasts in synovial tissue from patients with rheumatoid arthritis (RA). We have found that the majority of CD8 T cells in RA synovium have an unusual phenotype characterized by low expression of classic cytotoxic proteins such as granzyme B, perforin, and granulysin. Instead, these cells express high amounts of granzyme K, which induces synovial fibroblasts to produce pro-inflammatory factors such as IL-6. Based on our preliminary data, we believe that granzyme K does more than simply activate synovial fibroblasts. We believe that granzyme K activates the complement system to induce so-called inflammatory priming of synovial fibroblasts, characterized by metabolic reprogramming and augmented activation to stimuli. The specific aims proposed here will investigate the interactions of CD8 T cells and synovial fibroblasts in three complementary ways. Aim 1 interrogates whether human granzyme K induces the metabolic reprograming associated with inflammatory priming and whether complement mediates the downstream effects of granzyme K. Aim 2 uses imaging mass cytometry, traditional immunofluorescence, and spatial transcriptomics to evaluate granzyme K+ CD8 T cells and their relationship with fibroblast subsets and complement deposition within the context of human synovial tissues. Aim 3 uses mouse models of inflammatory arthritis to determine the effects of granzyme K on clinical and cellular measures in inflammatory arthritis. This study combines mechanistic studies, patient-derived samples, mouse models, and cutting-edge transcriptomic technologies to provide the candidate new training in several key aspects of translational immunology. The candidates immediate career development goals are to gain experience with microscopy techniques, spatial transcriptomics, cellular metabolism, mouse models of autoimmune diseases, and bioinformatic analysis. A specific career development plan is described by both the candidate and her mentor Dr. Michael Brenner, MD, an expert in lymphocyte biologic and synovial inflammation. She also has the support of an Advisory Committee of experts in the areas in which she will build her skills. The candidate’s long-term goal is to attain a tenure-track faculty position pursuing research that integrates high-dimensional analysis of patient samples with detailed mechanistic studies to characterize cellular interactions within tissues in rheumatologic diseases, with the ultimate goal of identifying new cellular and molecular candidates for diagnosis and treatment of autoimmune diseases.