A Novel Population of Mesenchymal Progenitors with Hematopoietic Potential Originated from CD14- Peripheral Blood Mononuclear Cells

Hemopoietic system derived progenitor cells with mesenchymal features have been identified including CD14(+) monocyte-derived progenitors. However, it is unclear whether there are mesenchyme derived progenitors with hematopoietic potential. Herein, we identified a novel CD14(-) cell-derived population with both mesenchymal and hematopoietic features in rat peripheral blood, and this cell population is different from the CD14(+) monocyte-derived progenitors but designated peripheral blood multipotential mesenchymal progenitors (PBMMPs). Phenotype analysis demonstrated expression of mesenchymal markers in PBMMPs including BMPRs, Endoglin/CD105, Fibronectin (Fn), Vimentin (Vim), Collagen (Col) I/II/III along with hematopoietic marker CD34. CD14(+) cell-derived population shared the same characteristics with CFs. In mixed culture of CD14(+) and CD14(-) cells, PBMMPs were a predominant component and expressed CD29(high), CD73(high), CD34(high), CD45(low) and CD90. Except for the value of mixed T lymphocytes and CD14(+) cell-derived population, hematopoietic characters of cultured PBMMPs were indicated by CD14(-)/CD34(+)/CD45(-)/CD90(+). The mesenchymal origin was further confirmed by comparing PBMMPs with bone marrow stromal cells. Finally, we transplanted PBMMPs into a skin wound model, and results showed the specific potential of PBMMPs in not only extracellular matrix secretion but epidermal regeneration. This study provides evidence that peripheral blood contains common hematopoietic-mesenchymal progenitors from both hematopoietic and mesenchymal lineages, and CD34(+) mesenchymal progenitors are a possible alternative source of epidermal cells in wound healing.