West China Journal of Stomatology ›› 2017, Vol. 35 ›› Issue (5): 520-526.doi: 10.7518/hxkq.2017.05.015

• Orginal Article • Previous Articles     Next Articles

The role of extracellular signal regulated kinase 1/2 in mediating osteodifferentiation of human periodontal ligament cells induced by cyclic stretch

Jing Song1(), Dapeng Ren2, Shiguo Yan1, Jing Lan1, Xiao Yuan2,3, Qingyuan Guo3, Xiang-min Qi1()   

  1. 1. Stomatology Hospital of Shandong University, Shandong Provincial Key Laboratory of Oral Biomedicine, Jinan 250012, China
    2. Stomatology College of Qingdao University; Dept. of Orthodontics, The Affiliated Hospital of Qingdao University Medical College, Qingdao 266003, China
    3. Dept. of Orthodontics, Stomatological Center, The Affiliated Qingdao Municipal Hospital, Qingdao 266075, China
  • Received:2016-08-11 Revised:2016-12-09 Online:2017-10-01 Published:2017-10-01
  • Supported by:
    National Natural Science Foundation of China (31170891);Key Fund of Shandong Provincial Health Bureau (2011HD001)

Abstract:

Objective This study aimed to investigate the mechanism of cyclic stretch that promotesthe osteogenic diffe-rentiation of human periodontal ligament cells (hPDLCs) through the mediation of extracellular-signal-regulated kinase 1/2 (ERK1/2). Methods hPDLCs were isolated throughthe explant method and cultured in vitro. hPDLCs were mechanically stimulated by a multi-channel cell-stress-loading system for 1, 3, 6, 12, and 24 h. The magnitude of stretch was 10% defor-mation, and the frequency was 0.5 Hz. Nonloaded cells were used as control group. ERK1/2 activation was blocked by U0126, a specific ERK1/2 pathway inhibitor. Additionally, hPDLCs were transfected with adenoviral vector encoding dominant negative ERK1/2 (DN-ERK1/2) to continuouslyinhibit ERK1/2 activation. The mRNA and protein levels of target geneswere detected through real-time polymerase chain reaction and Western blot. Results Cyclic stretching promoted the expression of ERK1/2, osteocalcin (OCN) mRNA, and bone sialoprotein (BSP) mRNA. The expression of runt-related transcription factor (Runx) 2 protein and mRNA also increased at 3 and 6 h of cyclic stretching. The inhibition of ERK1/2 by U0126 and DN-ERK1/2 suppressed the expressionof Runx2 mRNA, OCN mRNA, BSP mRNA, Runx 2 protein, and p-ERK1/2 protein relative to that in stretched cells without the ERK1/2 inhibitor. Conclusion ERK1/2 is a critical molecule in the mediation ofthe osteogenic differentiation of hPDLCs under mechanical stimulation. ERK1/2 activation induced the elevation of Runx2 protein levels, which may be involved in the stretch-induced expressions of OCN and BSP.

Key words: periodontal ligament cells, osteogenic differentiation, cyclic stretch, extracellular signal regulated kinase 1/2

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