Label Retention Identifies a Multipotent Mesenchymal Stem Cell-Like Population in the Postnatal Thymus

The study identified a population of K5-expressing thymic stromal cells in the postnatal thymus that exhibited characteristics of mesenchymal stem cells (MSCs), such as the ability to differentiate into adipocytes, chondrocytes, and osteoblasts. These cells, identified through label-retention techniques, expressed markers similar to MSCs, including Sca1, PDGFRα, PDGFRβ, CD29, CD44, CD49F, and CD90. When cultured and transplanted, these cells contributed to thymic architecture, suggesting their role in maintaining functional thymic microenvironments. This indicated that the postnatal thymus contained a multipotent mesenchymal stem cell-like population that could be sustained in culture.