A human pluripotent stem cell based in vitro model for autoimmune Type-1 diabetes

Type-1 diabetes (T1D) is an autoimmune disorder characterized by destruction of pancreatic insulin-producing β-cells. Despite recent scientific advances, questions remain regarding the initial trigger and the mechanisms of disease. Development of human induced pluripotent stem cells (hiPSCs) opens new opportunities for cell replacement therapy and hiPSCs-derived β-cells (iPSC-β) can be attained in vitro following a stepwise differentiation protocol. Yet, preventing immune rejection of grafted cells without the use of immunosuppressant drugs remains a major challenge. To date, only murine systems exist for modeling T1D and no human model has been developed to sufficiently capture autoimmune responses, selectively triggered by β-cells. In the current research, we have developed a human in vitro platform in an autologous setting that recapitulates the effector/target interactions in an autoimmune response. To create target cells for in vitro autoimmune assays, hiPSCs were reprogrammed from T1D patients, expanded in 3D suspension cultures and differentiated to human pancreatic β and α-cells. A donor-matched response against target hiPSC-derived β-cells (iPSC- β) was achieved by co-cultures with perihelial blood mononuclear cells (PBMCs) derived from the same donor’s blood. When quantified by means of T-cell effector activation signatures, both CD4⁺ and CD8⁺ T-cells exhibit a stronger activation phenotype when stimulated against iPSC-β compared to iPSC-α. β-cell selectivity was also manifested by iPSC-β increased susceptibility to immune-mediated killing. Furthermore, T-cell responses were found to be T-cell receptor mediated. The in vitro model designed in this research can serve to study mechanisms of T1D autoimmunity in the absence of accessible biomaterial from patients.