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(definition) and develop a senescence-associated secretory phenotype (SASP) that can lead to senescence and dysfunction of neighboring cells through paracrine actions, contributing to β-cell failure. In this study, 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 β-cells and its potential implication in health and disease.