Skip Navigation LinksHome > December 2008 - Volume 122 - Issue 6 > Transforming Growth Factor-β1 Stimulates Chondrogenic Differ...
Plastic & Reconstructive Surgery:
doi: 10.1097/PRS.0b013e31818cbf44
Experimental: Original Articles

Transforming Growth Factor-β1 Stimulates Chondrogenic Differentiation of Posterofrontal Suture–Derived Mesenchymal Cells In Vitro

Xu, Yue M.D., Ph.D.; James, Aaron W. B.A.; Longaker, Michael T. M.D., M.B.A.

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Abstract

Background: Evidence from animal studies has associated transforming growth factor (TGF)-β signaling with both normal and premature cranial suture fusion. However, the mechanisms whereby this pleiotropic cytokine mediates suture fusion remain uncertain. The authors established cultures of suture-derived mesenchymal cells from normally fusing (posterofrontal) and patent (sagittal) sutures and examined the in vitro effects of TGF-β1 on these distinct cell populations.

Methods: Skulls were harvested from 80 5-day-old mice. Posterofrontal and sagittal sutures were dissected, and cultures of suture-derived mesenchymal cells were established. The mitogenic, osteogenic, and chondrogenic effects of recombinant TGF-β1 were then assessed on posterofrontal and sagittal suture–derived mesenchymal cells (1 to 10 ng/ml). Quantitative real-time polymerase chain reaction was used to examine the effects of TGF-β1 on gene expression.

Results: TGF-β1 significantly decreased proliferation of both posterofrontal and sagittal suture–derived mesenchymal cells, by bromodeoxyuridine incorporation assays (n = 6). TGF-β1 also inhibited osteogenesis in both suture-derived mesenchymal cells determined by alkaline phosphatase activity and mineralization (n = 3 for all assays). During chondrogenic differentiation, TGF-β1 markedly increased expression of chondrocyte-specific gene markers in posterofrontal suture–derived mesenchymal cells (Sox9, Col II, Aggrecan, and Col X) (p ≤ 0.05). In contrast, TGF-β1 did not increase chondrocyte-specific gene expression in sagittal suture–derived mesenchymal cells (n = 3).

Conclusions: Posterofrontal suture–derived mesenchymal cells retain significant capability for both osteogenic and chondrogenic differentiation in vitro. TGF-β1 induces in vitro chondrogenesis in posterofrontal but not sagittal suture–derived mesenchymal cells. Future studies will focus on elucidating the mechanisms whereby TGF-β signaling mediates chondrogenesis in posterofrontal suture–derived mesenchymal cells.

©2008American Society of Plastic Surgeons

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