17beta-estradiol promotes the odonto/osteogenic differentiation of stem cells from apical papilla via mitogen-activated protein kinase pathway

Introduction

Estrogen plays an important role in the osteogenic differentiation of mesenchymal stem cells, while stem cells from apical papilla (SCAP) can contribute to the formation of dentin/bone-like tissues. To date, the effects of estrogen on the differentiation of SCAP remain unclear.

Methods

SCAP was isolated and treated with 10^-7 M 17beta-estradiol (E2). The odonto/osteogenic potency and the involvement of mitogen-activated protein kinase (MAPK) signaling pathway were subsequently investigated by using methyl-thiazolyl-tetrazolium (MTT) assay, and other methods.

Results

MTT and flow cytometry results demonstrated that E2 treatment had no effect on the proliferation of SCAP in vitro, while alkaline phosphatase (ALP) assay and alizarin red staining showed that E2 can significantly promote ALP activity and mineralization ability in SCAP. Real-time reverse transcription polymerase chain reaction (RT-PCR) and western blot assay revealed that the odonto/osteogenic markers (ALP, DMP1/DMP1, DSPP/DSP, RUNX2/RUNX2, OSX/OSX and OCN/OCN) were significantly upregulated in E2-treated SCAP. In addition, the expression of phosphor-p38 and phosphor-JNK in these stem cells was enhanced by E2 treatment, as was the expression of the nuclear downstream transcription factors including phosphor-Sp1, phosphor-Elk-1, phosphor-c-Jun and phosphor-c-Fos, indicating the activation of MAPK signaling pathway during the odonto/osteogenic differentiation of E2-treated SCAP. Conversely, the differentiation of E2-treated SCAP was inhibited in the presence of MAPK specific inhibitors.

Conclusions

The ondonto/osteogenic differentiation of SCAP is enhanced by 10^-7 M 17beta-estradiol via the activation of MAPK signaling pathway.

The influence of β-tricalcium phosphate blocks containing extracellular matrix on osteogenic differentiation of rat bone marrow stromal cells

BACKGROUND

The aim of the present study is to assess the osteogenic differentiation of rat bone marrow stromal cells (RBMCs) in β-tricalcium phosphate (β-TCP) blocks containing extracellular matrix (ECM) produced by human alveolar bone periosteal cells (HABPCs).

METHODS

HABPCs were cultured in β-TCP blocks for 1 week (group 1) and 2 weeks (group 2). β-TCP blocks containing ECM were then created by drying the blocks for 3 days. RBMCs were cultured in the blocks containing ECM for 2 weeks. In the control group, RBMCs were cultured in β-TCP blocks alone for 2 weeks. HABPCs and RBMCs in the blocks were examined by histologic and immunohistochemical analyses.

RESULTS

Histology revealed a significantly higher number of HABPCs in the group 2 blocks than in the group 1 blocks. HABPCs produced several bone matrix proteins in the blocks, and these positive reactions in group 2 were significantly higher than in group 1. Both groups showed a significantly higher number of RBMCs than the control group. RBMCs produced osteopontin and osteocalcin in the blocks, and these positive reactions were significantly higher in both test groups than in the control group. The number of osteocalcin-positive reactions was higher in group 2 than in group 1.

CONCLUSION

Osteogenic differentiation of RBMCs cultured for 2 weeks in β-TCP blocks containing ECM was significantly higher than that of cells cultured for 1 week or without ECM.

Sequential induction of marrow stromal cells by FGF2 and BMP2 improves their growth and differentiation potential in vivo

BACKGROUND

repairing bone loss by autologous grafting requires that a patient's marrow stromal cells (MSCs) be collected and cultured until the number of cells is adequate for implantation. Currently used techniques allow a slow proliferation rate and produce a culture that contains only small amounts of pluripotent stem cells that will become osteoblasts in culture.

OBJECTIVE

to develop culture conditions that permit a rapid increase in the number of MSCs while retaining or improving their potential for complete differentiation in vivo.

RESULTS

sequential applications of low doses of basic fibroblast growth factor 2 (FGF2) and bone morphogenetic protein 2 (BMP2) improved the growth and differentiation potential of MSCs. FGF2 also elevated sensitivity of the cells to BMP2. BMP2 increased the syntheses of alkaline phosphatase (ALP), collagen type I and bone sialoprotein, while FGF2 increased the expression of osteocalcin (OC). Full induction as determined by the formation of mineralised nodules in vitro was observed within 7 days. Seeding the induced cells onto scaffolds and then implanting them into nude mice resulted in newly formed bone 4 weeks later. The results of real-time polymerase chain reaction (PCR) and Western blotting suggested that FGF2 increased the pool of committed osteoblasts by up-regulating the Cbfa1/Runx2 gene. The later stages of bone formation seemed to be induced by Cbfa1/Runx2-downstream factors such as BMP2, ALP, collagen type I, bone sialoprotein and OC.

CONCLUSION

the culture system that was developed increased both the proliferation of MSC and the proportion that developed into pre-osteoblasts.