SASP signature of beta-cells includes pro-inflammatory and stress response proteins

To define the senescence-associated secretory phenotype (SASP) of beta-cells, we used conditioned media (CM) generated from bleomycin-treated MIN6 cells and from senescent (beta-Gal-positive) primary beta-cells. In order to culture senescent beta-cells, we isolated islet, FACS-sorted them into beta-Gal-positive and negative populations, excluding immune cells through negative selection of CD45-positive and CD11beta-positive cells. For both the MIN6 and primary beta-cell models, we cultured cells in serum-free media to generate CM for proteomic analysis using the aptamer-based SomaScan platform. After FACS-sorting, beta-Gal-positive and negative primary beta-cells were plated separately in chamber slides or 96-well plates and incubated overnight at 37C and 7% CO2 in serum-free islet media to generate CM. Bleomycin-treated and control MIN6 cells were cultured for 24 hours in serum-free MIN6 media to generate CM. CM was analyzed using SomaScan at the Genomics Proteomics Core at Beth Israel Deaconess Medical Center.