A Novel Islet-Peripheral Blood Mononuclear Cell Coculture Model for Studying Type 1 Diabetes

Type 1 diabetes is a heterogeneous group of disorders majorly characterized by autoimmune destruction of pancreatic β-cells, resulting in absolute insulin deficiency. Current research models lack many functions critical for understanding the onset and progression of this disease in humans. Although isolated primary islets are considered the standard tool for diabetes research, their experimental use is challenging due to inherent heterogeneity in size, cellular composition and purity, as well as rapid decline in their functionality and viability ex vivo. Here we investigate a novel co-culture platform of peripheral blood mononuclear cells (PBMCs) and a uniform 3D islet model. Human islet microtissues, produced by optimized dissociation and controlled reaggregation of primary islet cells, were cultured in a one-islet per well format in 96-well plates. They displayed uniform, long-term (>28 days), and robust viability and function enabling high-throughput and longitudinal study of immune cell-endocrine cell interactions and β-cell function. PBMCs in their naïve form or following T-cell specific activation, were combined in various ratios with healthy or stressed islets - preconditioned with a mild cytokine cocktail. Co-culturing of naïve PBMCs and islet microtissues had only a minor impact on β-cell function. Whereas, combination of activated PBMCs and islet microtissues resulted in a PBMC-number dependent decline in islet health shown by increased basal insulin release and decreased glucose-stimulated insulin secretion, insulin content and PDX-1 positive nuclei within each microtissue. The observed destruction correlated with the amount of CD3+ cells infiltrating the microtissues and was significantly augmented by cytokine preconditioning. The established islet-PBMC co-culture platform represents a novel in vitro model to study the autoimmune component of T1D and to screen for compounds that could prevent immune-cell mediated destruction of pancreatic islets. Disclosure B. Yesildag: None. N. Perdue: None. J. Mir-Coll: Employee; Self; InSphero. Employee; Spouse/Partner; Roche Pharma. A. Biernath: None. A. Neelakandhan: None. F. Forschler: Employee; Self; InSphero. M.G. von Herrath: None. J.D. Wesley: Employee; Self; Novo Nordisk A/S.