*Purpose: Pluripotent stem cell (PSC) is a potential source of generating functional therapeutic cells for transplantation. Embryonic stem cells are of absolutely allogeneic origin. Induced PSC (iPSCs) can be generated from auto-somatic cells but lacking cost effectiveness. So, even in case of the iPSC-based therapy, pre-stocked safety validated allogeneic iPSC can have a great advantage. Eventually, allogeneic PSC-derived cells elicit the problem of rejection and long-term immunosuppression. Various attempts showed that transferring a certain type of donor cells is beneficial for allograft survival, however, obtaining such effective cells from each PSC donor is not feasible. Previous studies have revealed that thymus transplantation can regulate recipient immune response against allografts. This study aims to efficiently generate thymic epithelial-like tissue from PSC by gene transduction of Foxn1, and investigate its potential to regulate recipient immune reaction.

*Methods: We established a mouse iPSC line which expressed exogenous Foxn1 driven by human EF1α-promoter. We examined the effect of Foxn1 expression during in vitro differentiation of thymic epithelial cells (TECs). We performed iPSC-derived TECs transplantation into athymic nude mice to evaluate in vivo function. To examine their contribution to allograft survival, we transplanted iPSC-TECs to immunocompetent mice followed by skin transplantation.

*Results: Forced expression of Foxn1 during in vitro differentiation enhanced the induction efficiency of cells expressing TEC-related cell surface molecules. We observed CD3⁺TCRβ⁺ cells in recipient peripheral blood and CD4⁺CD8⁺ population within the cells recovered from grafts. T-cell receptor Vβ of CD4 and CD8 single positive T cells in recipient nude mice showed comparable complexity with wild-type mice and fetal thymus recipient nude mice. Following T cell-depleting regimen, iPSC-TECs transplantation to immunocompetent recipients significantly prolonged the survival of allogeneic skin from the same MHC background donor.

*Conclusions: Our data show that iPSC-derived TECs can be efficiently generated by gene transduction of Foxn1. In vivo experiment of mouse skin transplantation indicates the therapeutic potential of iPSC-TECs to prolong allograft engraftment.

« Back to 2019 American Transplant Congress