Role of p38 and TAK1 on TGF-β-induced effect on human dental pulp cells

• Main Authors: Wei-Ling Huang, 黃韋綾
• Other Authors: 鄭景暉
• Format: Others
• Language: en_US
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/35868524612497937206

碩士 === 國立臺灣大學 === 臨床牙醫學研究所 === 100 === Aim: Transforming growth factor β1 (TGF-β1) plays a role in repair and dentinogenesis in dental pulp cells. The purpose of this study is to investigate whether TGF-β1 stimulates the signaling pathways, TAK1 and p38, thereby influence the morphological changes, cell proliferation, collagen turnover and alkaline phosphatase in human dental pulp cells in vitro. Materials and Methods: Primary-cultured human dental pulp cells were pre-treated with SB203580 (p38 inhibitor) or 5Z-7-oxozeaenol(TAK1 inhibitor) 30 minutes before adding TGF-β1. Morphology of pulp cells was observed under light microscopy (100X). Cell proliferation was evaluated by MTT assay. Cell differentiation and mineralization were evaluated by alkaline phosphatase (ALP) staining and quantitative assay. Changes in mRNA expression (ALP and collagen) were determined by reverse-transcriptase polymerase chain reaction (RT-PCR). Collagen content was determined by Sircol Collagen assay. Result : In the dental pulp cells, TGF-β1 (10ng/ml) showed little effect on cell number and cell size under light microscopy (100X) and MTT assay. 5Z-7-oxozeaenol(TAK1 inhibitor) showed decrease in the number of dental pulp cells markedly but SB203580 (p38 inhibitor) did not. TGF-β1 (10ng/ml) decreased the ALP activity but SB203580 and 5Z-7-oxozeaenol could not reverse the effect. TGF-β1 (0.1 ng/ml) mildly increased the ALP expression and TGF-β1 (5 ng/ml) increased the collagen formation. These effects could be reversed by SB203580 and 5Z-7-oxozeaenol. According to the RT-PCR, SB203580 and 5Z-7-oxozeaenol could reverse the up-regulatory of collagen expression by TGF-β1 (10ng/ml). However, down-regulatory of ALP gene expression caused by TGF-β1 (10ng/ml) could not be reversed by SB203580 and 5Z-7-oxozeaenol. Conclusion: TAK1 may increase proliferation of human dental pulp cells. TGF-β1 (0.1 ng/ml) can increase ALP activity and TGF-β1 (5 or 10 ng/ml) can induce collagen formation in dental pulp cells via TAK1-p38 pathway. TAK1-p38 pathway may have no influence in down-regulatory of ALP activity in TGF-β1 (10 ng/ml).