Stem cell-derived tissue-associated regulatory T cells suppress autoimmune diabetes

Abstract

Abstract CD4+ regulatory T cells (Tregs) are essential for normal immune surveillance, and their dysfunction can lead the development of autoimmune diseases, such as type-1 diabetes. Pluripotent stem cells (PSCs) can be utilized to obtain a renewable source of healthy Tregs to treat autoimmune diabetes as they have the ability to produce almost all cell types in the body, including Tregs. However, the right conditions for the development of antigen (Ag)-specific Tregs from PSCs (i.e., PSC-Tregs) have not been fully defined. In this study, we developed a new approach to generate functional Ag-specific Tregs from induced PSC (iPSCs), i.e., iPSC-Tregs, which have the ability to suppress autoimmunity in a murine model of autoimmune diabetes in Ag-associated fashion. We retrovirally transduced murine iPSCs with a DsRed reporter construct containing genes of major histocompatibility complex (MHC) II (I-Ab)-restricted ovalbumin (OVA)-specific T cell receptor (TCR) and the transcriptional factor FoxP3. We in vitro differentiated the DsRed+ iPSC into OVA-specific iPSC-Tregs with an OP9 stromal cell line expressing Notch ligands DL1, DL4 and I-Ab in the presence of recombinant cytokines of rIL-7 and rFlt3L. We visualized the expression of CD3, TCR, CD4, CD25, and CTLA-4 on OVA-specific iPSC-Tregs. Moreover, adoptive transfer of such Tregs dramatically suppressed autoimmunity in a well-established OVA-induced model of autoimmune diabetes (RIP-OVA × OT-I double transgenic mice), including the inflammation and prevents the insulin secreting pancreatic beta cells from destruction. Our results indicate that PSCs can be used to develop Ag-specific Tregs, which have a therapeutic potential for autoimmune diabetes.