Unique Human and Mouse β-Cell Senescence-Associated Secretory Phenotype (SASP) Reveal Conserved Signaling Pathways and Heterogeneous Factors.

The aging of pancreatic -cells may undermine their ability to compensate for insulin resistance, leading to the development of type 2 diabetes (T2D). Aging -cells acquire markers of cellular senescence and develop a senescence-associated secretory phenotype (SASP) that can lead to senescence and dysfunction of neighboring cells through paracrine actions, contributing to -cell failure. In this study, we defined the -cell SASP signature based on unbiased proteomic analysis of conditioned media of cells obtained from mouse and human senescent -cells and a chemically induced mouse model of DNA damage capable of inducing SASP. These experiments revealed that the -cell SASP is enriched for factors associated with inflammation, cellular stress response, and extracellular matrix remodeling across species. Multiple SASP factors were transcriptionally upregulated in models of -cell senescence, aging, insulin resistance, and T2D. Single-cell transcriptomic analysis of islets from an in vivo mouse model of reversible insulin resistance indicated unique and partly reversible changes in -cell subpopulations associated with senescence. Collectively, these results demonstrate the unique secretory profile of senescent -cells and its potential implication in health and disease.