Effect of bFGF on the growth and differentiation of human apical papilla cells: Role of MEK/ERK signaling pathway
Date Issued
2015
Date
2015
Author(s)
Chen, Chih-Yu
Abstract
Aim : Basic fibroblast growth factor (bFGF) owns multiple biological functions in various tissues, and plays important roles in cell proliferation and differentiation. Human apical papilla cells have been reported to show characteristics of stem cells and are known as stem cells from apical papilla (SCAP). The purpose of this study is to investigate the effects of bFGF on apical papilla cells and the roles of MEK/ERK signaling. We hypothesize that bFGF regulates cell proliferation and differentiation through MEK/ERK. Materials and Methods : Primary-cultured human apical papilla cells were treated under different concentration with or without U0126 (an inhibitor of MEK/ERK). Cell proliferation was measured by MTT assay. The expressions of cell cycle-related and differentiation-related genes and proteins were examined by reverse transcription polymerase chain reaction (RT-PCR) and western blot, respectively. Phosphorylation of signaling molecules was examined by western blot. ALP activity was determined by ALP staining. FGF receptors (FGFRs) were detected by immunofluorescent (IF). Results : In human apical papilla cells, treatment of bFGF (10~500 ng/ml) enhanced the proliferation and the expression of cell cycle-related genes and proteins including cyclin B1, cdc2, and cdc25c. In osteogenic/ dentinogenic differentiation, bFGF promoted the expression of Runx2 and osteocalcin, but ALP activity was suppressed by treatment of bFGF for 5 days. FGFR1, 2, 3 and 4 were expressed abundantly in apical papilla cells. Using U0126 solely decreased the inherent proliferative ability in apical papilla cells, and combined with bFGF inhibited the bFGF-induced enhancement of proliferation and expression of cell cycle-related genes and proteins. The increase of osteocalcin and TIMP1 induced by bFGF was repressed by U0126, while Runx2 and ALP were not changed. Besides, ALP activity attenuated by bFGF could not be reversed by U0126. Conclusion : The effect of bFGF on apical papilla cells is complicated and might be divergent depending on the duration of treatment. MEK/ERK pathway plays important roles in miscellaneous cell functions. These results would be useful for clinical therapies in the future, including apexogenesis and pulp-dentin complex regeneration.
Subjects
apical papilla cells
bFGF
FGFR
alkaline phosphatase
Type
thesis
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