Isolation and Characterization of Human Suture Mesenchymal Stem Cells In Vitro

Background and Objectives: Cranial sutures play a critical role in adjustment of skull development and brain growth. Premature fusion of cranial sutures leads to craniosynostosis. The aim of the current study was to culture and characterize human cranial suture mesenchymal cells in vitro. Methods: The residual skull tissues, containing synostosed or contralateral suture from three boys with right coronal suture synostosis, were used to isolate the suture mesenchymal cells. Then, flow cytometry and multilineage differentiation were performed to identify the typical mesenchymal stern cell (MSC) properties. Finally, we used quantitative real-time polymerase chain reaction (RT-PCR) to detect the mRNA expression of osteogenesis and sternness related genes. Results: After 3 to 5 days in culture, the cells migrated from the tissue explants and proliferated parallelly or spirally. These cells expressed typical MSC markers, CD73, CD90, CD10.5, and could give rises to osteocytes, adipocytes and chondrocytes. RT PCR showed relatively higher levels of Runx2, osteocalcin and FGF2 in the fused suture MSCs than in the normal cells. However, BMP3, the only protein of BMP family that inhibits osteogenesis, reduced in synostoscd suture derived cells. The expression of effector genes remaining cell sternness, including Bmi1, Gli1 and Axin2, decreased in the cells migrated from the affected cranial sutures. Conclusions: The MSCs from prematurely occlusive sutures overexpressed osteogenic related genes and down-regulated sternness-related genes, which may further accelerate the osteogenic differentiation and suppress the self-renewal of stem cells leading to craniosynostosis.