3111-LB: Activated Stellate Cell-Mediated Decrease in ß-Cell Insulin Content in an In Vitro Model of Type 3c Diabetes

Introduction and Objective: Type 3c diabetes (T3cD) is characterised by relative maintenance of islet mass, decreased β:α cell ratio and loss of β-cell end-differentiation. Activated stellate cells in close proximity to islets have been circumstantially implicated in diabetes pathogenesis. We aimed to determine if stellate cell activation leads to changes in β-cell phenotype and function. Methods: Islet stellate cells (ISCs) established by outgrowth from human islets in adherent culture. Activation status was determined by α-SMA / SMAD2/3 staining and collagen (Col1a1 ELISA) / cytokine (MSD) secretion. Impact of ISC secretome on β-cells was determined by RNAseq (EndoC-βH1) and insulin content (Ins1E). Results: ISC cultures became 100% α-SMA positive with activation confirmed by positive SMAD2/3 staining; secretion of collagen (Col1a1) and proinflammatory cytokines (highest fold increase over 7 day culture: IL6 (13x), IL1β (5x), and TNFα (7x)). Incubation of EndoC-βH1 cells with ISC secretome led to upregulation of stress markers, downregulation of key transcription factors (Figure 1). Insulin content was decreased in INS1E treated with ISC secretome (control: 292.9±25.1 µg/100mg protein; treated: 270.9±12.1 µg/100mg protein; p<0.05). Conclusion: In vitro ISC activation led to proinflammatory cytokine secretion, β-cell stress, altered phenotype and decreased insulin content supporting stellate cell-mediated β-cell dysfunction in T3cD. Disclosure C. Brack: None. N. Kattner: None. Y. Al-Selwi: None. E. Westholm: None. A. Wendt: None. L. Eliasson: None. J. Shaw: None. Funding Diabetes UK - 24/0006697, Cystic Fibrosis Trust - SRC019Newcastle University