Mechanical Tensional Force Regulates Expression of Periostin in Human Periodontal Ligament Cells
Date Issued
2015
Date
2015
Author(s)
Hsu, Yu-Jen
Abstract
Periostin was classified as one of the matricellular proteins predominantly expressed in collagen-rich connective tissues, including heart valves, tendons, perichondrium, periosteum, and periodontal ligament. The periostin knock-out mice showed loss of the tissue integrity of the periodontium in response to mechanical loading, and developed an early-onset periodontal disease-like phenotype. Previous studies suggest that periostin is essential for connective tissue homeostasis and important to maintain the integrity and function of periodontal ligament in respond to mechanical stress. Mechanical strain regulates periostin expression involved of multiple signaling pathways. In the present study, we hypothesized that low-level and high-level tensional force differentially regulates TGF-β1 and periostin expression in human PDL cells. We investigated the TGF-β1 signaling and periostin expression in human PDL cells subjected to low- and high- level cyclic tensional force (3% versus 10% elongation) for 4, 8, 24, and 48 hours in a Flexercell Strain Unit. Our results revealed that application of 3% or 10% cyclic tensional force activated TGF-β1 signaling pathway and the protein level of periostin in human PDL cells. The stimulatory effect of 10% tensional force was more intensive than that of 3%. However, the high-level tensional force (10%) with long duration (48 hours) inhibited the expression of periostin. Although mechanical stimulation of cyclic tensional force for 4 hours induced an increase in the protein level of periostin, there was no significant change in the mRNA level. The mechanically-induced periostin expression was significantly decreased after the treatment of an inhibitor of TGF-β type I receptor (SB431542) for 24 hours, but not for 4 hours. Furthermore, the inhibitors of actin polymerization (Cytochalasin D), actin depolymerization (Jasplakinolide), or FAK autophosphorylation (Y15), which disrupting cytoskeletal dynamics, decreased mechanically-induced periostin expression at 4 hours. It implied that cytoskeletal dynamics for reorganization of actin filaments preceded the TGF-β1 signaling pathway in the process of mechanotransduction. In conclusion, the results of our study suggest that different levels of mechanical stress differentially regulate the expression of periostin in PDL cells to ensure the integrity of the periodontium in response to occlusal load. An intact cytoskeletal dynamics and activation of TGF-β1 signaling pathway are essential for mechanically-induced periostin expression in human PDL cells.
Subjects
periostin
cyclic tensional force
cytoskeletal dynamics
TGF-β1 signaling pathway
SDGs
Type
thesis
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