• Journal of Periodontal and Implant Science
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• v.36 no.3
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• pp.783-796
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• 2006

The periodontium is a topographically complex organ consisting of epithelial tissue, soft and mineralized tissues. Structures comprising the periodontium include the gingiva, periodontal ligament (PDL) , cementum and the alveolar bone. The molecular mechanism of differentiation in PDL fibroblast cells remain unclear. Amino acid transporters play an important role in supplying nutrition to normal and cancer cells and for cell proliferation. Amino acid transport system L is a major nutrient transport system responsible for the Na+-independent transport of neutral amino acids including several essential amino acids. The system L is divided into two major subgroups, the L-type amino acid transporter 1 (LAT1) and the L-type amino acid transporter 2 (LAT2). In this study, the expression pattern of amino acid transport system L was, therefore, investigated in the differentiation of PDL fibroblast cells. To determine the expression level of amino acid transport system L participating in intracellular transport of amino acids in the differentiation of PDL fibroblast cells, it was examined by RT-PCR, observation of cell morphology, Alizaline red-S staining and uptake analysis after inducing experimental differentiation in PDL fibroblast cells isolated from mouse molar teeth. The results are as follows. 1. The LAT1 mRNA was expressed in the early stage of PDL fibroblast cell differentiation. This expression level was gradually reduced by differentiation- inducing time and it was not observed after the late stage. 2. The expression level of LAT2 mRNA was increased in time-dependent manner during differentiation induction of PDL fibroblast cells. 3. There was no changes in. the expression level of 4F2hc mRNA, the cofactor of LAT1 and LAT2, during differentiation of PDL fibroblast cells. 4. The expression level of ALP mRNA was gradually increased and the expression level of Col I mRNA was decreased during differentiation of PDL fibroblast cells. 5. The L-leucine transport was reduced by time from the early stage to the late stage in PDL fibroblast cell differentiation. As the results, it is considered that among neutral ammo acid transport system L in differentiation of PDL fibroblast cells, the LATl has a key role in cell proliferation in the early stage of cell differentiation and the LAT2 has an important role in the late stage of cell differentiation for providing cells with neutral amino acids including several essential amino acids.

• Archives of Pharmacal Research
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• v.21 no.4
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• pp.398-405
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• 1998

We investigated the effects of triterpene acids (TAs), ursolic acid (UA) and oleanolic acid (OA), on the induction of proliferation and differentiation of normal rat mammary epithelial cells (RMEC) or organoids cultured in Matrigel or primary culture system. To elucidate the effects, we tested their differentiation inducing activities with intercellular communication ability, cell cycle patterns, induction of apoptosis, and morphological differentiation in the three dimensional extracellular culture system. To study the changes of RMEC subpopulation in culture, the cultured cells were isolated, immunostained with peanut lectin (PNA) and anti-Thy-1.1 antibody and then analyzed with flow cytometry. Four different subpopulations, such as PNA and Thy-1.1 negative cells (B-), PNA positive cells (PNA+), Thy-1.1 positive cells (Thy-1.1+), PNA and Thy-1.1 positive cells (B+), were obtained and the size of each subpopulation was changed in culture with time in the presence of TAs. Intercellular communication was observed in culture for 7 days in TAs-treated cells, but not in culture for 4 days with scrape-loading dye transfer technique. $G_2$/M phase cells and the number of apoptotic population were increased in TAs-treated groups in cell cycle analyses. S phase fractions were reduced and the change of $G_1$ phase cells was not observed. The colonies with distinct multicelfular structures, such as stellate, ductal, webbed, squamous, lobulo-ductal colonies, were observed in Matrigel culture and the frequencies of each colony were changed in the presence of TAs. These results suggest that UA and OA have differentiation inducing effects on rat mammary epithelial cells in primary or in Matrigel culture.

• Molecules and Cells
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• v.43 no.1
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• pp.58-65
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• 2020

Fat mass and obesity-associated (FTO) gene helps to regulate energy homeostasis in mammals by controlling energy expenditure. In addition, FTO functions in the regulation of obesity and adipogenic differentiation; however, a role in osteogenic differentiation is unknown. This study investigated the effects of FTO on osteogenic differentiation of C3H10T1/2 cells and the underlying mechanism. Expression of osteogenic and endoplasmic reticulum (ER) stress markers were characterized by reverse-transcriptase polymerase chain reaction and western blotting. Alkaline phosphatase (ALP) staining was performed to assess ALP activity. BMP2 treatment increased mRNA expression of osteogenic genes and FTO. Overexpression of FTO increased expression of the osteogenic genes distal-less homeobox5 (Dlx5) and runt-related transcription factor 2 (Runx2). Activation of adenosine monophosphate-activated protein kinase (AMPK) increased FTO expression, and there was a positive feedback loop between FTO and p-AMPK. p-AMPK and FTO induced mild ER stress; however, tunicamycin-induced severe ER stress suppressed FTO expression and AMPK activation. In summary, FTO induces osteogenic differentiation of C3H10T1/2 cells upon BMP2 treatment by inducing mild ER stress via a positive feedback loop with p-AMPK. FTO expression and AMPK activation induce mild ER stress. By contrast, severe ER stress inhibits osteogenic differentiation by suppressing FTO expression and AMPK activation.

• International journal of thyroidology
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• v.10 no.2
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• pp.71-76
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• 2017

Background and Objectives: The role of thyroid-stimulating hormone (TSH) signaling on osteoblastic differentiation is still undetermined. The aim of this study was to investigate the effects of 5-aza-2'-deoxycytidine (5-azacytidine) on TSH-mediated regulations of osteoblasts. Materials and Methods: MG63, a human osteoblastic cell-line, was treated with 5-azacytidine before inducing osteogenic differentiation using osteogenic medium (OM) containing L-ascorbic acid and ${\beta}$-glyceophosphate. Bovine TSH or monoclonal TSH receptor stimulating antibody (TSAb) was treated. Quantitative real-time PCR analyses or measurement of alkaline phosphatase activities were performed for evaluating osteoblastic differentiation. Results: Studies for osteogenic-related genes or alkaline phosphatase activity demonstrated that treatment of TSH or TSAb alone had no effects on osteoblastic differentiation in MG63 cells. However, treatment of 5-azacytidine, per se, significantly increased osteoblastic differentiation and combination treatment of 5-azacytidine and TSH or TSAb in the condition of OM showed further significant increase of osteoblastic differentiation. Conclusion: Stimulating TSH signaling has little effects on osteoblastic differentiation in vitro. However, in the condition of epigenetic modification using inhibitor of DNA methylation, TSH signaling positively affects osteoblastic differentiation in human osteoblasts.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.169.2-170
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• 2003

Erythropietin (EPO), a hematopoietic factor is also required for normal brain development, and its receptor is localized in brain. Therefore, it is possible that EPO could act as a neurotropic factor inducing differentiation of neurons. The present study, we therefore investigated whether EPO can increase differentiation of undifferentiated cortical neuron isolated from postneonatal (Day 1) rat brains and PC12 cell, undifferentiated dopaminagic cell line. EPO dose (1-100 U/ml) dependently increased cell differentiation and expression of differentiation marker gene (neurofilament and tyrosine hydroxylase) in both cells. (omitted)

• Biomedical Science Letters
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• v.23 no.4
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• pp.295-302
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• 2017

Mononuclear osteoclast precursors derived from hematopoietic progenitors fuse together and then become multinucleated mature osteoclasts by macrophage-colony stimulating factor (M-CSF) and receptor activator of nuclear factor-${\kappa}B$ ligand (RANKL). Especially, the binding of RANKL to its receptor RANK provides key signals for osteoclast differentiation and bone-resorbing function. RANK transduces intracellular signals by recruiting adaptor molecules such as TNFR-associated factors (TRAFs), which then activate mitogen activated protein kinases (MAPKs), Src/PI3K/Akt pathway, nuclear factor-${\kappa}B$ (NF-${\kappa}B$) and finally amplify NFATc1 activation for the transcription and activation of osteoclast marker genes. This review will briefly describe RANKL-RANK signaling pathways and key molecules critical for osteoclast differentiation.

• YAKHAK HOEJI
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• v.37 no.5
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• pp.532-537
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• 1993

Angiogenesis refers to the formation of new capillary blood vessels, or neovascularization occurring under various physical conditions, such as development of the embryo, formation of corpus luteum, wound healing and pathological conditions including tumor growth and metastases, hemangiomas, diabetic retinopathy, rheumatoid arthritis. There are many evidences that angiogenesis is important for the progressive growth of solid tumors and also permits the shedding of metastatic tumors from the primary site. Thus, treatment of angiogenesis inhibitors might be a novel strategy for tumor growth inhibition. Normal vascular endothelial cells are in a state of differentiation and angiogenic endothelial cells migrate and proliferate, and they subsequently differentiate into vessel-forming quiescent phenotype cells, Therfore, it was speculated that a modifier of cell differentiation could also affect angiogenesis. In order to identify new antiangiogenic factors, the research was conducted to estimate the inhibitory activities of cell differentiation agents by means of chick embryo chorioallantoic membrane(CAM) assay. Hence, we have established the CAM assay for the screening of antiangiogenic agents. Using the CAM assay, we found that ursolic acid, a tumor cell differentiation-inducing agent, showed a markedly inhibitory effect on chick embryonic angiogenesis.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.9
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• pp.5379-5383
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• 2013

Therapeutic effects of zoledronic acid (ZOL) on giant cell tumour of bone (GCT) have been proven. Apoptosis induction was considered to be one of the mechanisms of ZOL tumour inhibition. In this study, we presented the possibility of an osteogenic differentiation stimulation mechanism of ZOL and further investigated dosage and time effects. We treated stromal cells of GCT (GCTSC) with ZOL for 48 hours at different concentrations ($0{\mu}M$, $0.01{\mu}M$, $0.1{\mu}M$, $1{\mu}M$, 5${\mu}M$, $30{\mu}M$) and assessed apoptotic and osteogenic differentiation markers with immunohistochemical techniques and real-time quantitative RT-PCR. Our results suggested that ZOL enhanced mRNA expression of Cbfa-1, osterix and osteocalcin genes with a maximum effect at $1{\mu}M$ in GCTSC. Time course experiments indicated a time dependent osteogenic differentiation effect. In conclusion, ZOL may be considered as an adjuvant in the treatment of GCT not only by inducing apoptosis but also by stimulating osteogenic differentiation of remaining tumor stromal cells after surgery.

• Journal of Microbiology and Biotechnology
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• v.22 no.12
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• pp.1790-1794
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• 2012

Recently, it has been suggested that $p27^{Kip1}$, the cell cycle regulatory protein, plays a pivotal role in the progression of normal differentiation in murine embryonic stem (mES) cells. In the current study, we investigated the role of $p27^{Kip1}$ in the regulation of differentiation and apoptotic induction using Western blotting, quantitative real-time RT-PCR, and small interfering RNA (siRNA) assays and confocal laser scanning microscopic analysis of H9 human ES (hES) cells and H9-derived embryoid bodies (EBs) grown for 10 ($EB_{10}$) and 20 days ($EB_{20}$). Our results demonstrate that the proteins $p27^{Kip1}$ and cyclin D3 are strongly associated with cellular differentiation, and, for the first time, show that up-regulation of $p27^{Kip1}$ protects hES cells from inducing differentiation-associated and caspase 3-dependent apoptosis.

• Journal of Microbiology and Biotechnology
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• v.17 no.7
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• pp.1113-1119
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• 2007

Human bone marrow-derived mesenchymal stem cells (hBMMSCs) must differentiate into osteogenic cells to allow for successful bone regeneration. In this study, we investigated the effects of different combinations of three soluble osteogenic differentiation-inducing factors [L-ascorbic acid (AC), ${\beta}$-glycerophosphate (${\beta}G$), and bone morphogenic protein-2 (BMP-2)] and the presence of a hydroxyapatite (HA) substrate on hBMMSC osteogenic differentiation in vitro. hBMMSCs were cultured in medium containing various combinations of the soluble factors on culture plates with or without HA coating. After 7 days of culture, alkaline phosphatase (ALP) activity, calcium deposition, and osteoprotegerin (OPG) and osteopontin (OPN) expression were measured. The effects of individual and combined factors were evaluated using a factorial analysis method. BMP-2 predominantly affected expression of early markers of osteogenic differentiation (ALP and OPG). HA had the highest positive effect on OPN expression and calcium deposition. The interaction between AC, ${\beta}G$, and HA had the second highest positive effect on ALP activity.