1269-OR: Elevated Interferon-Gamma Response Signatures Observed at Single-Cell Resolution in Islet Beta Cells from Donors with Type 1 Diabetes

Introduction and Objective: Inflammatory cytokine signaling contributes to beta-cell autoimmunity in type 1 diabetes (T1D), but the contribution of interferon-gamma (IFNγ) versus other inflammatory pathways remains unclear. We hypothesized that beta-cells from donors with T1D display elevated IFNγ response relevant to autoimmunity. Methods: We identified differentially expressed genes from two publicly available human islet bulk RNA-seq datasets from donors with T1D and compared these data sets to IFNγ and other cytokine-treated beta-cell models (human islets, EndoC-βH1, rat 832/13, etc.). Overlapping genes were scored as module signatures in single-cell RNA-seq from human pancreatic islets (control, autoantibody-positive, T1D donors). Chromatin immunoprecipitation identified STAT1 and NF-κB/p65 binding sites within key genes present across multiple species. Results: We observed 162 genes increased in expression when comparing T1D datasets and cytokine signaling models, enriching for interferon response, antigen presentation, and viral defense pathways. Single-cell analysis revealed beta cells in T1D had significantly elevated IFNγ/cytokine module scores versus controls (p<0.001), with progressive increases from control to autoantibody-positive to T1D. ChIP-seq analysis revealed 44 genes with cooperative STAT1/p65 binding, while 57 genes lacked direct transcription factor binding but were enriched for interferon-stimulated genes (ISG15, MX2, RSAD2), indicating distinct regulatory mechanisms. Conclusion: Islet beta-cells in human T1D display elevated IFNγ response signatures detectable at single-cell resolution, with progressive activation correlating with disease stage. Transcriptional responses reflect both direct STAT1-mediated pathways and discrete mRNA regulation, supporting IFNγ signaling as a key component of autoimmunity in T1D.