Senescent beta-cells exhibit a unique secretory phenotype that promotes inflammation and remodeling of the extracellular environment

Type 2 Diabetes (T2D) patients have higher proportions of senescent beta-cells than their non-diabetic counterparts (Aguayo-Mazzucato et al., 2019). Senescent beta-cells may propagate dysfunction in neighboring cells through the paracrine effects of the senescence-associated secretory phenotype (SASP). To address the heterogeneity in beta-cell SASP expression and its role in T2D, we measured expression levels of beta-cell SASP signature genes in a mouse model of acute insulin resistance using the insulin receptor antagonist, S961. We have previously shown that this model induces hyperglycemia and accelerates beta-cell senescence (Aguayo-Mazzucato et al., 2019). Pancreatic islets were isolated from 3 groups of mice: a control group, a treated group of mice with surgically installed osmotic pumps secreting S961 for 2 weeks, and a third group in which mice recovered from S961 treatment for two weeks. During treatment, mice developed marked hyperglycemia and hyperinsulinemia which was completely reversed during the two-week recovery period. Islets were dispersed into single cells and scRNASeq was performed using the 10x Genomics Chromium Single Cell Gene Expression Assay. Overall design: C57Bl6/J male mice (7- to 8-month-old retired breeders) from the Jackson Laboratory were used. Pumps with the insulin receptor antagonist S961 were surgically installed in mice for two weeks as described previously (Aguayo-Mazzucato et al., 2019). Three groups of mice were used: control (pumps with no S961), S961, and recovered (mice with pumps removed). Treated mice received 20nM of S961 per week. Islets were isolated from mice belonging to each group for single-cell RNA-seq and cultured overnight. Islets were treated with 1 mL of TrypLE Express for 10 minutes at 37C,with vortexing every 3 minutes. Digestion was stopped with media with serum. After filtering, transcriptomic analysis was performed using the 10x Genomics Chromium Single Cell Gene Expression Assay core at BWH.