Song Jing1, Ren Dapeng2, Yan Shiguo1, Lan Jing1, Yuan Xiao3, Guo Qingyuan4, Qi Xiangmin1. 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. 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. 4. Dept. of Orthodontics, Stomatological Center, The Affiliated Qingdao Municipal Hospital, Qingdao 266075, China.
Abstract
OBJECTIVE: This study aimed to investigate the mechanism of cyclic stretch that promotesthe osteogenic differentiation of human periodontal ligament cells (hPDLCs) through the mediation of extracellular-signal-regulated kinase 1/2 (ERK1/2). METHODS: hPDLCs were isolated through the 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% deformation, 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. CONCLUSIONS: 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.
OBJECTIVE: This study aimed to investigate the mechanism of cyclic stretch that promotesthe osteogenic differentiation of human periodontal ligament cells (hPDLCs) through the mediation of extracellular-signal-regulated kinase 1/2 (ERK1/2). METHODS: hPDLCs were isolated through the 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% deformation, 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. CONCLUSIONS: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.
Authors: Xian Fan; Jill A Rahnert; Tamara C Murphy; Mark S Nanes; Edward M Greenfield; Janet Rubin Journal: J Cell Physiol Date: 2006-05 Impact factor: 6.384
Authors: G Pagès; P Lenormand; G L'Allemain; J C Chambard; S Meloche; J Pouysségur Journal: Proc Natl Acad Sci U S A Date: 1993-09-15 Impact factor: 11.205
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