HSCI Retreat 2019 Abstract 2

ABSTRACT

Our understanding of the causes and possible treatments for Type 1 Diabetes (T1D) has been profoundly limited by a lack of in vitro models that recapitulate human T1D disease progression. As the foundation for such a model, we have successfully differentiated human induced pluripotent stem cells into functional β cells (hiPSC-β cells) that can reverse diabetes in mice. Herein, we propose that an in vitro platform can model human T1D using hiPSC-β cells and hypothesize that the complex immune features of human T1D can be reproduced in vitro using the hiPSC-β cells and donor-matched immune cells. In our experiments, a cell-type specific, donor-matched response against the hiPSC-β cells but not the hiPSC-α cells was achieved in vitro. Specifically, co-culturing donor-matched hiPSC-β cells and PBMCs resulted in activation of the effector cells, as assayed through cytokine secretion, induction of activation surface markers in T cells and specific killing of the hiPSC-β cells. Most importantly, we sought to determine whether the β cell killing was mediated by specific T cell receptor (TCR) engagement. We performed two experiments to test the requirement for direct TCR recognition of hiPSC-β cells in stimulating T cell activation. First, we incubated the targets β cells with an HLA-class I blocking antibody to prevent binding of T cells with the target cells and second, we used a transwell co-culture system that eliminated direct contact between the immune cells and hiPSC-β cells. Both experiment approaches prevented T cell activation, thereby confirming the TCR engagement hypothesis. The developed T1D in vitro platform to measure immune responses will be used in future experiments aimed to test the ability of protecting hiPSC-β cells from autoimmune attack. Collectively these data suggest that we developed a novel tool for patient-specific testing of immunoprotection strategies of the hiPSC-β cells in vitro before autologous transplantation.