The Effect of Uniaxial Mechanical Stretch on Wnt/β-Catenin... : Journal of Craniofacial Surgery (original) (raw)

Original Articles

The Effect of Uniaxial Mechanical Stretch on Wnt/β-Catenin Pathway in Bone Mesenchymal Stem Cells

Zhao, Chuang MD; Li, Yunfeng DDS, MD; Wang, Xuemei MD; Zou, Shujuan DDS, MD; Hu, Jing DDS, MD; Luo, En DDS, MD

*State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu

†Department of Oral and Maxillofacial Surgery, The Second Hospital of Dalian Medical University, Dalian, China.

Address correspondence and reprint requests to En Luo, DDS, MD and Jing Hu, DDS, MD, State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China; E-mail: [email protected] (EL) and [email protected] (JH)

Received 22 May, 2016

Accepted 3 September, 2016

This study was supported by grants from National Nature Science Foundation of China (No 81271106 and 30973346).

The authors report no conflicts of interest.

Abstract

Wnt/β-catenin signal is required in bone formation and remodling, but little is known about whether Wnt/β-catenin signal could promote osteogenic differentiation of rat bone marrow mesenchymal stem cells (BMSCs) after uniaxial mechanical stretch. In this study, rat BMSCs were identified by flow cytometry and used for mechanical stretch. A custom-made uniaxial dynamic stretch apparatus was applied for rat BMSCs stretch. There were 2 groups in the study: the mechanical stretch group and the nonstretch control group. Cell morphology, alkaline phosphatase (ALP) activity, mRNA levels (Wnt3a, Lrp5, β-catenin, as well as Runx2 were evaluated using quantitative real-time reverse transcription-polymerase chain reaction) and protein levels (β-catenin and Runx2 were examined using western blot) were observed in both groups. The authors finally found that not only the cell proliferation, ALP activity, but also mRNA expression of Wnt3a, Lrp5, β-catenin, and Runx2 in BMSCs were markedly elevated by mechanical stretch than the controls. Protein levels of β-catenin and Runx2 were significantly higher than that of control as well. Activation of mechanical stretch was partially reversed by DKK-1, a classical inhibitor of Wnt/β-catenin signal. These results demonstrate that uniaxial mechanical stretch could stimulate osteogenic differentiation and proliferation of BMSCs by activating the Wnt/β-catenin signaling.