Generation of Functional Thymic Epithelium from Human Embryonic Stem Cells that Supports Host T Cell Development

• hESCs are differentiated into TEPs in vitro
• TEP specification requires regulation of TGFβ, BMP4, RA, Wnt, Shh, and FGF signaling
• hESC-derived TEPs mature into functional TECs upon transplantation into athymic mice
• TECs support the generation of new T cells that are functional in vitro and in vivo

SummaryInducing immune tolerance to prevent rejection is a key step toward successful engraftment of stem-cell-derived tissue in a clinical setting. Using human pluripotent stem cells to generate thymic epithelial cells (TECs) capable of supporting T cell development represents a promising approach to reach this goal; however, progress toward generating functional TECs has been limited. Here, we describe a robust in vitro method to direct differentiation of human embryonic stem cells (hESCs) into thymic epithelial progenitors (TEPs) by precise regulation of TGFβ, BMP4, RA, Wnt, Shh, and FGF signaling. The hESC-derived TEPs further mature into functional TECs that support T cell development upon transplantation into thymus-deficient mice. Importantly, the engrafted TEPs produce T cells capable of in vitro proliferation as well as in vivo immune responses. Thus, hESC-derived TEP grafts may have broad applications for enhancing engraftment in cell-based therapies as well as restoring age- and stress-related thymic decline.

Graphical AbstractFigure optionsDownload high-quality image (306 K)Download as PowerPoint slide