FGF2 SUPPRESSED CCL11 EXPRESSION IN HUMAN DENTAL PULP-DERIVED MSCs

The regulation of the mesenchymal stem cell (MSC) programming mechanism promises great success in regenerative medicine. Tissue regeneration has been associated not only with the differentiation of MSCs, but also with the microenvironment of the stem cell niche that involves various cytokines and immune cells in the tissue regeneration site. In the present study, fibroblast growth factor 2 (FGF2), the principal growth factor for tooth development, dental pulp homeostasis and dentin repair, was reported to affect the expression of cytokines in human dental pulp‑derived MSCs. FGF2 significantly inhibited the expression of chemokine C‑C motif ligand 11 (CCL11) in a time‑ and dose‑dependent manner in the SDP11 human dental pulp‑derived MSC line. This inhibition was diminished following treatment with the AZD4547 FGF receptor (FGFR) inhibitor, indicating that FGF2 negatively regulated the expression of CCL11 in SDP11 cells. Furthermore, FGF2 activated the phosphorylation of p38 mitogen‑activated protein kinase (p38 MAPK), extracellular signal‑regulated kinase 1/2 (ERK1/2) and c‑Jun N‑terminal kinases (JNK) in SDP11 cells. The mechanism of the FGFR‑downstream signaling pathway was then studied using the SB203580, U0126 and SP600125 inhibitors for p38 MAPK, ERK1/2, and JNK, respectively. Interestingly, only treatment with SP600125 blocked the FGF2‑mediated suppression of CCL11. The present results suggested that FGF2 regulated the expression of cytokines and suppressed the expression of CCL11 via the JNK signaling pathway in human dental pulp‑derived MSCs. The present findings could provide important insights into the association of FGF2 and CCL11 in dental tissue regeneration therapy

ピエゾ型機械受容チャネル1による歯の発生過程におけるWNTシグナルと一次繊毛発現の調整

Signal transmission from the mechanical forces to the various intracellular activities is a fundamental process during tissue development. Despite their critical role, the mechanism of mechanical forces in the biological process is poorly understood. In this study, we demonstrated that in the response to hydrostatic pressure (HP), the piezo type mechanosensitive ion channel component 1 (PIEZO1) is a primary mechanosensing receptor for odontoblast differentiation through coordination of the WNT expression and ciliogenesis. In stem cells from human exfoliated deciduous teeth (SHED), HP significantly promoted calcium deposition as well as the expression of odontogenic marker genes, PANX3 and DSPP, and WNT related-genes including WNT5b and WNT16, whereas HP inhibited cell proliferation and enhanced primary cilia expression. WNT signaling inhibitor XAV939 and primary cilia inhibitor chloral hydrate blocked the HP-induced calcium deposition. The PIEZO1 activator Yoda1 inhibited cell proliferation but induced ciliogenesis and WNT16 expression. Interestingly, HP and Yoda1 promoted nuclear translocation of RUNX2, whereas siRNA-mediated silencing of PIEZO1 decreased HP-induced nuclear translocation of RUNX2. Taken together, these results suggest that PIEZO1 functions as a mechanotransducer that connects HP signal to the intracellular signalings during odontoblast differentiation

Therapeutic benefits of factors derived from stem cells from human exfoliated deciduous teeth for radiation-induced mouse xerostomia

Radiation therapy for head and neck cancers is frequently associated with adverse effects on the surrounding normal tissue. Irreversible damage to radiation-sensitive acinar cells in the salivary gland (SG) causes severe radiation-induced xerostomia (RIX). Currently, there are no effective drugs for treating RIX. We investigated the efficacy of treatment with conditioned medium derived from stem cells from human exfoliated deciduous teeth (SHED-CM) in a mouse RIX model. Intravenous administration of SHED-CM, but not fibroblast-CM (Fibro-CM), prevented radiation-induced cutaneous ulcer formation (p < 0.0001) and maintained SG function (p < 0.0001). SHED-CM treatment enhanced the expression of multiple antioxidant genes in mouse RIX and human acinar cells and strongly suppressed radiation-induced oxidative stress. The therapeutic effects of SHED-CM were abolished by the superoxide dismutase inhibitor diethyldithiocarbamate (p < 0.0001). Notably, quantitative liquid chromatography-tandem mass spectrometry shotgun proteomics of SHED-CM and Fibro-CM identified eight proteins activating the endogenous antioxidant system, which were more abundant in SHED-CM than in Fibro-CM (p < 0.0001). Neutralizing antibodies against those activators reduced antioxidant activity of SHED-CM (anti-PDGF-D; p = 0.0001, anti-HGF; p = 0.003). Our results suggest that SHED-CM may provide substantial therapeutic benefits for RIX primarily through the activation of multiple antioxidant enzyme genes in the target tissue

ピエゾ型機械受容イオンチャネル1は間葉系幹細胞の分化運命決定の調節因子として機能する

The extracellular environment regulates the dynamic behaviors of cells. However, the effects of hydrostatic pressure (HP) on cell fate determination of mesenchymal stem cells (MSCs) are not clearly understood. Here, we established a cell culture chamber to control HP. Using this system, we found that the promotion of osteogenic differentiation by HP is depend on bone morphogenetic protein 2 (BMP2) expression regulated by Piezo type mechanosensitive ion channel component 1 (PIEZO1) in MSCs. The PIEZO1 was expressed and induced after HP loading in primary MSCs and MSC lines, UE7T-13 and SDP11. HP and Yoda1, an activator of PIEZO1, promoted BMP2 expression and osteoblast differentiation, whereas inhibits adipocyte differentiation. Conversely, PIEZO1 inhibition reduced osteoblast differentiation and BMP2 expression. Furthermore, Blocking of BMP2 function by noggin inhibits HP induced osteogenic maker genes expression. In addition, in an in vivo model of medaka with HP loading, HP promoted caudal fin ray development whereas inhibition of piezo1 using GsMTx4 suppressed its development. Thus, our results suggested that PIEZO1 is responsible for HP and could functions as a factor for cell fate determination of MSCs by regulating BMP2 expression

COMBINATION OF IONS PROMOTES GINGIVAL FIBROBLAST MIGRATION

Wound healing is a dynamic process that involves highly coordinated cellular events, including proliferation and migration. Oral gingival fibroblasts serve a central role in maintaining oral mucosa homeostasis, and their functions include the coordination of physiological tissue repair. Recently, surface pre‑reacted glass‑ionomer (S‑PRG) fillers have been widely applied in the field of dental materials for the prevention of dental caries, due to an excellent ability to release fluoride (F). In addition to F, S‑PRG fillers are known to release several types of ions, including aluminum (Al), boron (B), sodium (Na), silicon (Si) and strontium (Sr). However, the influence of these ions on gingival fibroblasts remains unknown. The aim of the present study was to examine the effect of various concentrations of an S‑PRG filler eluate on the growth and migration of gingival fibroblasts. The human gingival fibroblast cell line HGF‑1 was treated with various dilutions of an eluent solution of S‑PRG, which contained 32.0 ppm Al, 1,488.6 ppm B, 505.0 ppm Na, 12.9 ppm Si, 156.5 ppm Sr and 136.5 ppm F. Treatment with eluate at a dilution of 1:10,000 was observed to significantly promote the migration of HGF‑1 cells. In addition, the current study evaluated the mechanism underlying the mediated cell migration by the S‑PRG solution and revealed that it activated the phosphorylation of extracellular signal‑regulated kinase 1/2 (ERK1/2), but not of p38. Furthermore, treatment with a MEK inhibitor blocked the cell migration induced by the solution. Taken together, these results suggest that S‑PRG fillers can stimulate HGF‑1 cell migration via the ERK1/2 signaling pathway, indicating that a dental material containing this type of filler is useful for oral mucosa homeostasis and wound healing

Path-Planning System for Radioisotope Identification Devices Using 4π Gamma Imaging Based on Random Forest Analysis

We developed a path-planning system for radiation source identification devices using 4π gamma imaging. The estimated source location and activity were calculated by an integrated simulation model by using 4π gamma images at multiple measurement positions. Using these calculated values, a prediction model to estimate the probability of identification at the next measurement position was created by via random forest analysis. The path-planning system based on the prediction model was verified by integrated simulation and experiment for a 137Cs point source. The results showed that 137Cs point sources were identified using the few measurement positions suggested by the path-planning system