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

The aging of pancreatic β-cells may undermine their ability to compensate for insulin resistance, leading to the development of type 2 diabetes (T2D). Aging β-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 b-cell failure. Herein, we defined the β-cell SASP signature based on unbiased proteomic analysis of conditioned media of cells obtained from mouse and human senescent β-cells and a chemically-induced mouse model of DNA damage capable of inducing SASP. These experiments revealed that the β-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 β-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 β-cell subpopulations associated with senescence. Collectively, these results demonstrate the unique secretory profile of senescent b-cells and its potential implication in health and disease.