Introduction and Objective: Senescence of β cells occurs in type 1 diabetes (T1D); however, how senescence-associated β cell identity and inflammatory programs evolve across disease progression, inflammatory niches, and immunomodulatory treatments is unknown. In this study, we defined the temporal and spatial transcriptional dynamics of β cell senescence, identity, and inflammation during T1D progression and following anti-CD3 (aCD3) therapy. Methods: scRNA-seq data of islets from 4-14-week-old female NOD mice were analyzed to quantify β cell senescence, identity, and inflammatory transcriptional programs using curated gene modules. We performed GeoMx Digital Spatial Profiling of islet regions stratified by insulitis severity in aCD3- or IgG-treated NOD mice and differential gene expression and pathway enrichment analyses. Results: scRNA-seq revealed gradual increases in β cell senescence and inflammatory signature genes with disease progression. Despite rising senescence, β cell identity gene programs remained preserved at early stages. Senescence intensity stratification showed that senescence was associated with a decline in β cell identity at later stages. Spatial profiling showed that β cells within severe-insulitis islets exhibited elevated senescence and inflammatory signaling with reduced β cell identity genes, whereas non-insulitis islets maintained intact transcriptional profiles. aCD3 treatment reduced severe-insulitis regions, increased β cell numbers, decreased senescence and inflammatory gene programs in β cells, and shifted transcriptional profiles toward metabolic and homeostatic pathways. Conclusion: These studies indicate that β cell senescence is a dynamic process shaped by disease stage, inflammatory context, and immune pressure. aCD3 therapy reduces senescence-associated inflammatory and identity alterations, supporting coordinated temporal, spatial, and immune regulation of β cell states in T1D. Disclosure J. Lee: None. R.B. Kang: None. A. Garcia-Ocana: Advisory Panel; Current; Paulex Bio. G. Lu: None. Funding NIH-NIDDK (DK105015)
LEE et al. (Fri,) studied this question.