title: Mechanical stretch increases the proliferation while inhibiting the osteogenic differentiation in dental pulp stem cells.
abstract: Dental pulp stem cells (DPSCs), which can differentiate into several types of cells, are subjected to mechanical stress by jaw movement and occlusal forces. In this study, we evaluated how the uniaxial mechanical stretch influences proliferation and differentiation of DPSCs. DPSCs were isolated and cultured from male Sprague-Dawley rats. Cultured DPSCs were identified by surface markers and the differentiation capabilities as adipocytes or osteoblasts. To examine the response to mechanical stress, uniaxial stretch was exposed to cultured DPSCs. We evaluated the impact of stretch on the intracellular signaling, proliferation, osteogenic differentiation, and gene expressions of DPSCs. Stretch increased the phosphorylation of Akt, ERK1/2, and p38 MAP kinase as well as the proliferation of DPSCs. The stretch-induced proliferation of DPSCs was abolished by the inhibition of the ERK pathway. On the other hand, stretch significantly decreased the osteogenic differentiation of DPSCs, but did not affect the adipogenic differentiation. We also confirmed mRNA expressions of osteocalcin and osteopontin were significantly suppressed by stretch. In conclusion, uniaxial stretch increased the proliferation of DPSCs, while suppressing osteogenic differentiation. These results suggest a crucial role of mechanical stretch in the preservation of DPSCs in dentin. Furthermore, mechanical stretch may be a useful tool for increasing the quantity of DPSCs in vitro for regenerative medicine.
authors.affiliation: Department of Removable Prosthodontics, School of Dentistry, Aichi-Gakuin University, Nagoya, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Hata
authors.forename: Keiko
authors.initials: K
authors.lastname: Naruse
authors.forename: Shogo
authors.initials: S
authors.lastname: Ozawa
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: Nobuhisa
authors.initials: N
authors.lastname: Nakamura
authors.forename: Norinaga
authors.initials: N
authors.lastname: Kojima
authors.forename: Maiko
authors.initials: M
authors.lastname: Omi
authors.forename: Yuki
authors.initials: Y
authors.lastname: Katanosaka
authors.forename: Toru
authors.initials: T
authors.lastname: Nishikawa
authors.forename: Keiji
authors.initials: K
authors.lastname: Naruse
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Tatsuaki
authors.initials: T
authors.lastname: Matsubara
mesh_terms: D017667:Adipocytes / Q000166:cytology / Q000378:metabolism; D050156:Adipogenesis; D000818:Animals; D002454:Cell Differentiation; D049109:Cell Proliferation; D002478:Cells, Cultured; D003782:Dental Pulp / Q000166:cytology*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005786:Gene Expression Regulation; D008297:Male; D010006:Osteoblasts / Q000166:cytology / Q000378:metabolism; D015675:Osteocalcin / Q000235:genetics / Q000378:metabolism; D010012:Osteogenesis; D053495:Osteopontin / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013234:Stem Cells / Q000166:cytology* / Q000201:enzymology; D013314:Stress, Mechanical; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D015675:Osteocalcin; D053495:Osteopontin; D051057:Proto-Oncogene Proteins c-akt; D048049:Extracellular Signal-Regulated MAP Kinases; D048051:p38 Mitogen-Activated Protein Kinases