Bioinformatics and Genomics Programme Roberto Castro

31/03/202310:00MARIE CURIEBioinformatics and Genomics ProgrammeRoberto CastroUniverstity of Florida Diabetes Institute. Holger Russ Lab."Modeling human autoimmune diabetes using stem cells and genetic engineering"Host: Ferrer, JorgeAbstract:Modeling human autoimmune diabetes using stem cells and genetic engineering

ß cell replacement therapy holds the promise of reversing Type 1 Diabetes (T1D) in patients. However, key challenges such as ß cell scarcity, donor incompatibility, and recurrent autoimmunity remain. In this work, we describe the optimization of a 3D directed differentiation protocol to generate an abundant source of stem-cell-derived insulin-producing ß cells (sBC). These sBC generated in the lab are functional and release insulin in response to glucose, a hallmark of ß cell function. These cells effectively address the problem of ß cell scarcity. Nonetheless, here we showed that sBC are indeed immunogenic and can be subjected to immune mediated destruction. We found that sBC presents key autoimmune antigens, such as preproinsulin (PPI) peptides, through HLA class I molecules. Furthermore, we show that T cells targeting these PPI peptides are stimulated after co-culture with sBC. This represents a potentially risk for immune destruction after transplantation into patients with T1D. We then hypothesized that genetically engineering of sBC can offer localized protection from immune destruction. Our data shows that PD-L1 expression and HLA class I deletion on sBC inhibits self-reactive T cell activation. However, these genetic modifications are not sufficient to prevent complete sBC graft rejection in a humanized mouse model for autoimmune diabetes. Potential reasons and alternatives to overcome the remaining challenges are discuss in this work. We also present an in vitro system to recapitulate key aspects of human autoimmune diabetes in a precise manner. Our assays can be used to model the specific autoimmune interaction between T1D patient derived sBC and self-reactive T cells in an autologous setting. In sum, we present a stem cell platform to model and eventually overcome the key remaining challenges of ß cell replacement therapy and provide novel insights into a potential cure for T1D.