Generation of Functional Patient-Specific Thymus Organoids From Human Pluripotent Stem Cells (hPSCs) Using Air-Liquid...

Area of Science:

• Immunology
• Regenerative Medicine
• Developmental Biology

Background:

• The thymus is essential for adaptive immunity but declines with age, impacting T-cell production.
• Current methods for generating functional thymic tissue from human pluripotent stem cells (hPSCs) have limitations, including reliance on external tissues and lack of patient specificity.
• Previous work demonstrated differentiation of thymic epithelial progenitors (TEPs) but required in vivo maturation for functional thymic epithelial cells (TECs).

Purpose of the Study:

• To develop a reproducible protocol for generating functional, isogenic, patient-specific stem cell-derived thymic organoids (sTOs) in vitro.
• To create a system that supports the development and maturation of human thymic epithelial cells and T-cells from hPSCs.
• To enable in vitro studies of human thymic function, including T-cell development and selection.

Main Methods:

• Directed differentiation of hPSCs to generate thymic epithelial progenitors (TEPs), hematopoietic progenitor cells (HPCs), and mesenchymal cells from the same hPSC line.
• Generation of multicellular stem cell-derived thymic organoids (sTOs) by combining these differentiated cell types.
• Culture of sTOs at the air-liquid interface to support in vitro development.

Main Results:

• A revised protocol successfully generated functional, isogenic stem cell-derived thymic organoids (sTOs).
• The generated sTOs supported in vitro development and maturation of human thymic epithelial cells in a patient-specific manner.
• sTOs facilitated human T-cell development from co-cultured stem cell-derived hematopoietic progenitor cells.
• The organoids showed potential for supporting both positive and negative selection of developing T-cells in vitro.

Conclusions:

• Functional, multicellular stem cell-derived thymic organoids (sTOs) can be reproducibly generated from hPSCs.
• These patient-specific sTOs provide a valuable in vitro model for studying human thymic epithelial cell and T-cell development.
• sTOs hold promise for advancing regenerative medicine strategies and understanding thymic selection processes.