Cyclic Tensile Stress During Physiological Occlusal Force Enhances Osteogenic Differentiation of Human Periodontal Ligament Cells via ERK1/2-Elk1 MAPK Pathway

Li, Lü; Han, Minxuan; Sheng, Li; Wang, Lin; Xu, Yan

doi:10.1089/dna.2013.2070

Cited by 42 publications

(55 citation statements)

References 53 publications

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“…We also detected osteogenesis‐related gene expression and ALP activity as well as Alizarin red staining, to verify the promotion of osteogenic differentiation of hPDLCs after LIPUS stimulation during LPS‐induced inflammation. RUNX2 played a crucial role in the regulation of osteogenesis differentiation, and the osteogenic capacity was enhanced by upregulating the expression of RUNX2 . OPN is regarded as a specific marker in the stage of matrix formation and maturity of osteoblast, and its expression increase is consistent with the maturity of osteoblasts .…”

Section: Discussionmentioning

confidence: 99%

LIPUS inhibited the expression of inflammatory factors and promoted the osteogenic differentiation capacity of hPDLCs by inhibiting the NF‐κB signaling pathway

Liu

Zhou

et al. 2019

J of Periodontal Research

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Background and Objectives As a chronic infectious disease, periodontitis could lead to tooth and bone loss. Low‐intensity pulsed ultrasound (LIPUS) is a safe, noninvasive treatment method to effectively inhibit inflammation and promote bone differentiation. However, the application of LIPUS in curing periodontitis is still rare. Our study aimed to explore the ability of LIPUS to inhibit inflammatory factors and promote the osteogenic differentiation capacity of human periodontal ligament cells (hPDLCs), and its underlying mechanism. Material and Methods Human periodontal ligament cells were obtained and cultured from the premolar tissue samples for experiments. First, hPDLCs were treated for 24 hours using lipopolysaccharide (LPS) and then exposed to LIPUS (10 mW/cm2, 30 mW/cm2, 60 mW/cm2, and 90 mW/cm2) to determine the appropriate intensity to inhibit expression of the inflammatory factors interleukin‐6 (IL‐6) and interleukin‐8 (IL‐8) expression. The expression of IL‐6 and IL‐8 was detected by real‐time PCR and enzyme‐linked immunosorbent assay. The safety of the most appropriate intensity of LIPUS was tested by a cell counting kit 8 test and an apoptosis assay. Then, LPS‐induced hPDLCs were treated in osteogenic medium for 7‐21 days with or without LIPUS (90 mW/cm2, 30 min/d) stimulation. The osteogenic genes RUNX2, OPN, OSX, and OCN were measured by real‐time PCR. Additionally, osteogenic differentiation capacity was determined using alkaline phosphatase (ALP) staining, ALP activity analysis, and Alizarin red staining. The activity of the nuclear factor‐kappa B (NF‐κB) signaling pathway was determined by western blotting, real‐time PCR, immunofluorescence, and pathway blockade assays. Results Lipopolysaccharide significantly upregulated the production and gene expression of IL‐6 and IL‐8, while LIPUS stimulation significantly inhibited IL‐6 and IL‐8 expression in an intensity‐dependent manner. LIPUS (90 mW/cm2) was chosen as the most appropriate intensity, and there was no detrimental influence on cell proliferation and status with or without osteogenic medium. In addition, consecutive stimulation with LIPUS (90 mW/cm2) for 30 min/d for 7 days could also inhibit IL‐6 and IL‐8 gene expression, upregulate the expression of the osteogenesis‐related genes RUNX2, OPN, OSX, and OCN, and promote osteogenic differentiation capacity in osteogenic medium in inflamed hPDLCs. The NF‐κB signaling pathway was inhibited with LIPUS (90 mW/cm2) via inhibition of the phosphorylation of IκBα and the translocation of p65 into the nucleus in inflamed hPDLCs. Additional investigations of the NF‐κB inhibitor, BAY 11‐7082, revealed that LIPUS (90 mW/cm2) acted similarly to BAY 11‐7802 to inhibit the NF‐κB signaling pathway and increase osteogenesis‐related genes and promote the osteogenic differentiation capacity of inflamed hPDLCs. Conclusion Low‐intensity pulsed ultrasound (90 mW/cm2) stimulation could be a safe method to inhibit IL‐6 and IL‐8 in hPDLCs by inhibiting the NF‐κB signaling pathway. The effect of LIPUS (90 mW...

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Section: Discussionmentioning

confidence: 99%

LIPUS inhibited the expression of inflammatory factors and promoted the osteogenic differentiation capacity of hPDLCs by inhibiting the NF‐κB signaling pathway

Liu

Zhou

et al. 2019

J of Periodontal Research

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“…Cyclic tensile strain on PDL cells in vitro is used to model the occlusal force during mastication in vivo (Li et al, 2013; Pinkerton et al, 2008), which is considerably different from the continuous tensile strain. The difference was clearly demonstrated in the gene expression of inflammatory cytokines, such as IL-6.…”

Section: Discussionmentioning

confidence: 99%

Novel device for application of continuous mechanical tensile strain to mammalian cells

et al. 2017

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During orthodontic tooth movement, the periodontal ligament (PDL) is exposed to continuous mechanical strain. However, many researchers have applied cyclic tensile strain, not continuous tensile strain, to PDL cells in vitro because there has been no adequate device to apply continuous tensile strain to cultured cells. In this study, we contrived a novel device designed to apply continuous tensile strain to cells in culture. The continuous tensile strain was applied to human immortalized periodontal ligament cell line (HPL cells) and the cytoskeletal structures of HPL cells were examined by immunohistochemistry. The expression of both inflammatory and osteogenic markers was also examined by real-time reverse transcription polymerase chain reaction. The osteogenic protein, Osteopontin (OPN), was also detected by western blot analysis. The actin filaments of HPL cells showed uniform arrangement under continuous tensile strain. The continuous tensile strain increased the expression of inflammatory genes such as IL-1β, IL-6, COX-2 and TNF-α, and osteogenic genes such as RUNX2 and OPN in HPL cells. It also elevated the expression of OPN protein in HPL cells. These results suggest that our new simple device is useful for exploring the responses to continuous tensile strain applied to the cells.

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“…In the tension side of the OTM, new bone forms as a result of tensile strain on the PDLCs. Accordingly, the expressions of osteogenic markers in PDLCs, such as core‐binding factor α1 (Cbfα1, also known as RUNX2), osterix (OSX), osteocalcin (OCN), collagen type I (COL I), and alkaline phosphatase (ALP), are found to be elevated under tensile strain, suggesting an osteoblastic phenotype of PDLCs …”

Section: Introductionmentioning

confidence: 99%

TAZ contributes to osteogenic differentiation of periodontal ligament cells under tensile stress

Wang

et al. 2019

J of Periodontal Research

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Background and objective Bone remodeling during orthodontic treatment is achieved by the osteogenesis of human periodontal ligament cells (PDLCs) subjected to mechanical loadings. Transcriptional co‐activator with PDZ‐binding motif (TAZ) mediates bone remodeling in response to extracellular mechanical signals. This study aims to investigate the role of TAZ in osteogenesis of PDLCs under tensile strain. Materials and methods A uniaxial cyclic tensile stress (CTS) at 12% elongation and 6 cycles/min (5 s on and 5 s off) was applied to PDLCs. The osteogenic differentiation was determined by the protein and gene expressions of osteogenic markers using qRT‐PCR and Western blot, respectively, and further by alkaline phosphatase (ALP) activity and Alizarin Red S staining. The interaction of TAZ with core‐binding factor α1 (Cbfα1) was examined by co‐immunoprecipitation. The immunofluorescence histochemistry was used to examine the nucleus aggregation of TAZ and the reorganization of actin filaments. Moreover, small interfering RNA‐targeting TAZ (TAZsiRNA) was used for TAZ inhibition and Y‐27632 was employed for Ras homologue‐associated coiled‐coil protein kinase (ROCK) signaling blockage. Results CTS clearly stimulated the nucleus accumulation of TAZ and its interaction with Cbfα1. CTS‐induced osteogenesis in PDLCs was significantly abrogated by the infection with TAZsiRNA, as shown by the decreased stained nodules and protein expressions of Cbfα1, collagen type I, osterix, and osteocalcin, along with the inhibition of β‐catenin signaling. Moreover, ROCK inhibition by Y‐27632 hindered TAZ nucleus aggregation and its binding with Cbfα1, which subsequently lead to the decreased osteoblastic differentiation of PDLCs. Conclusions Taken together, we propose that TAZ nucleus localization and its interaction with Cbfα1 are essential for the CTS‐induced osteogenic differentiation in PDLCs. And such TAZ activation by CTS could be mediated by ROCK signaling, indicating the pivot role of ROCK‐TAZ pathway for PDLCs differentiation.

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Cyclic Tensile Stress During Physiological Occlusal Force Enhances Osteogenic Differentiation of Human Periodontal Ligament Cells via ERK1/2-Elk1 MAPK Pathway

Cited by 42 publications

References 53 publications

LIPUS inhibited the expression of inflammatory factors and promoted the osteogenic differentiation capacity of hPDLCs by inhibiting the NF‐κB signaling pathway

LIPUS inhibited the expression of inflammatory factors and promoted the osteogenic differentiation capacity of hPDLCs by inhibiting the NF‐κB signaling pathway

Novel device for application of continuous mechanical tensile strain to mammalian cells

TAZ contributes to osteogenic differentiation of periodontal ligament cells under tensile stress

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