Beta Cell Heterogeneity in the Interferon Alpha Response

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1 PROJECT SUMMARY 2 Type 1 Diabetes (T1D) is an autoimmune disease characterized by destruction of insulin producing β-cells due 3 to a combination of genetic risk and an unknown environmental trigger. A leading hypothesis for the 4 environmental trigger is viral infection, during which the innate immune system releases various cytokines and 5 interferons. Interferon alpha (IFN-α) has been long implicated in disease pathogenesis, with its presence 6 observed in islets of donors with early-onset T1D. It has also been shown that IFN-α induces ER stress, MHC 7 class 1 overexpression, and islet apoptosis, classical hallmarks of T1D development. For many years it was 8 thought that all β-cells were destroyed in individuals with T1D. Recently, this dogma has been challenged with 9 the discovery of residual insulin positive β-cells in donors with long-standing T1D. This suggests that β-cells are 10 heterogeneous, with one population of β-cells able to survive conditions of high stress. With these observations 11 in mind, the central goal of this proposal is to understand mechanisms behind heterogeneity of human β-cell 12 ROS response following IFN-α insult. I hypothesize that ROS accumulating β-cells, termed ‘ROSponders’ 13 contain a unique molecular signature that promotes this heterogeneity in ROS accumulation, causing this subset 14 of cells to be more susceptible to oxidative stress and apoptosis. I will test this hypothesis through three specific 15 aims. Experiments in aim 1 are designed to characterize the molecular signature of ROSponders, with the goal 16 of identifying what makes them more susceptible to this ROS accumulation. In aim 2, I will determine the origin 17 of accumulating ROS. In aim 3, I will determine the fate of ROSponders through longitudinal intravital imaging. 18 With completion of these aims, the goal is to determine the mechanism and consequence of this observed 19 heterogeneity in ROS response. Importantly, through transcriptomics, this work will aim to identify novel targets 20 to prevent β-cell dysfunction under diabetogenic conditions, allowing for the development of future therapeutics 21 for disease prevention and/or treatment. A comprehensive understanding of islet function in early diabetes 22 pathogenesis and the use of cutting-edge techniques proposed in this grant will enable me to develop as a 23 scientist and set me on a trajectory to make real and lasting impacts in the field of diabetes. This F31 award 24 includes a 2-year training plan designed to achieve 4 main objectives: 1) develop a strong comprehension of 25 techniques and concepts used in diabetes research, 2) train in the use of different microscopy techniques, 3) 26 enhance written and oral scientific communication, and 4) train in the use and handling of mouse models for 27 diabetes research. In addition, I will benefit from the collaborative research environment provided by the Center 28 for Diabetes and Metabolic Diseases at the Indiana University School of Medicine. I will also benefit from an 29 advisory committee consisting of a diverse team of carefully selected and established NIH funded investigators 30 and a supportive research environment in the laboratory. 31 32 33 34