Differentiation of nerve-derived adult pluripotent stem cells into osteoblastic and endothelial cells

Abstract

BACKGROUND CONTEXT: Stem cell-involved tissue engineering has gained dramatic attention as a therapeutic strategy for tissue regeneration including bone repair. However, the currently available possibilities to use embryonic stem cells and induced pluripotent stem cells (iPCs) face potential ethical issues, as well as risks of malignant transformation and immune rejection. Recently identified peripheral nerve-derived adult pluripotent stem cells (NEDAPS) that quickly proliferate after exposure to bone morphogenetic protein-2 (BMP-2) or nerve trauma and exhibit many embryonic stem cell characteristics may provide an attractive source cells for a variety of regenerative therapies.

PURPOSE: The study aimed to examine the differentiation potential of the NEDAPS cells into osteoblastic cells and endothelial cells.

STUDY DESIGN/SETTING: An in vitro investigation was undertaken to induce mouse NEDAPS cells into the phenotypes of osteoblastic and endothelial cells.

METHODS: NEDAPS cells were isolated from low-dose BMP-2-exposed mouse sciatic nerves by collagenase and trypsin extraction. The cells were cultured in a stem cell maintenance medium, and the expression of KLF4, Sox2, c-Myc, and Oct4 before differentiation was confirmed. The cells were then subcultured in a complete osteogenic cell induction medium or endothelial cell growth medium, respectively, at 37 degrees C and 5% CO2 atmosphere. Histologic, morphologic, and molecular assessments were performed 7 days later.

RESULTS: The cells propagated in complete osteogenic medium for 7 days showed strong staining for type I collagen and alkaline phosphatase, suggesting the structural and functional properties of the osteoblastic cells. Further, real-time polymerase chain reaction (RT-PCR) revealed a significant expression of the osteoblast markers osteocalcin, osteopontin, and type I collagen. Similarly, the cells in endothelial growth medium were successfully differentiated into cobblestone-shaped endothelial cells expressing vascular endothelial growth factor (VEGF) receptors Flk-1 and Flt-1 demonstrated by RT-PCR.

CONCLUSIONS: NEDAPS cells are readily induced to osteoblastic and endothelial cells, suggesting therapeutic potential for bone repair and other regenerative therapies.