Stem cell-based modeling of type 1 diabetes to accelerate translation of therapies - ABSTRACT Type 1 diabetes (T1D) is an autoimmune disease with complex underlying genetics and environmental triggers that results in immune-mediated destruction of insulin-producing beta cells. While animal models of spontaneous autoimmune diabetes have provided substantial insights into the pathogenesis of the disease, translating this information into efficient therapies for human T1D has been extremely challenging. Improved preclinical research models are thus needed to accelerate the development of therapeutic interventions for T1D patients. In our previous work, we have built in vitro assays and humanized mouse models that enable rejection of human stem cell-derived beta cells by allogeneic T cells and genetically engineered CD8+ T cells. In this project, we propose to improve current models by creating a stem cell-based multi- cellular platform that integrates diverse types of immune cells with stem cell-derived islets (SC- islets). We will combine complementary approaches developed by our multi-PI team of immunologists, beta cell biologists, and stem cell biologists, and will build upon them to refine our ability to recapitulate autoimmune pathogenesis. In the initial development period, we will focus on three critical aspects of our model: 1) optimizing differentiation of islets and macrophages from the same cell line; 2) identifying the right TCRs to engineer T cells; 3) selecting the mouse strain to be used for assembling all components in vivo. We have selected two T1D iPSC lines with high-risk human leukocyte antigen (HLA) alleles that will be used to generate the relevant cell types. Aim 1 will focus on generating SC-islets, Aim 2 on SC-macrophages, and Aim 3 on engineering islet-reactive T cells. During the UH3 phase, we aim to complete assembly of the model (Aim 4) and begin pre-clinical testing of candidate strategies designed to protect SC-islets from immune destruction (Aim 5). Given the critical role of T cells in the development and progression of T1D, we will focus on agents that target effector T cells. Aside from T cell-mediated rejection, beta cells are vulnerable to inflammatory cytokines secreted by immune cells. These cytokines can also shape the inflammatory response, which ultimately influences the recruitment and activation of autoreactive T cells in the islets. We will thus test if immune destruction of beta cells can be prevented using T cell targeting strategies and agents that reduce inflammation in islets. Successful optimization of this platform will accelerate translation of new therapies by enabling their preclinical testing in an autoimmune setting.
