• Biomedical Science Letters
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• v.13 no.4
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• pp.355-360
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• 2007

In order to evaluate on the cytotoxicity of methyl mercury (MM) and antioxidant effect of phenolic compound, poncirin against MM-induced cytotoxicity, XTT assay was performed to determine the cell viability after human skin fibroblasts (Detroit 51) were grown in the media containing various concentrations of methylmercuric chloride (MMC). And also, the antioxidant effect of poncirin on the cytotoxicity induced by MMC was examined by cell viability and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity in these cultures. MMC decreased cell viability in dose-dependent manner in these cultures and the midcytotoxicity value was determined at concentration of 30 ${\mu}M$ MMC after human skin fibroblasts were treated with $10\sim50{\mu}M$ MMC for 72 hours, respectively. MMC was highly toxic on cultured human skin fibroblasts by toxic criteria. MMC-mediated cytotoxicity was related with oxidative stress by the diminution of toxic effect according to the treatment of vitamin E. In the antioxidant effect of poncirin, it showed vitamin E-like DPPH radical scavenging activity at 90 ${\mu}g/ml$ poncirin and also, remarkably increased cell viability compared with MMC-treated group. From these results, it is suggested that MMC-mediated cytoxicity was highly toxic and was related with oxidative stress in cultured human skin fibroblasts, and also phenolic compound such as poncirin showed the protection on MMC-induced cytotoxicity by antioxidant effect in these cultures.

• Journal of Life Science
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• v.24 no.12
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• pp.1301-1307
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• 2014

Adipose-derived stem cells (ADSCs) are considered promising tools for tissue regeneration. However, ADSCs have very poor proliferation capacity. Therefore, fetal bovine serum (FBS) is generally added to the culture media of ADSCs. As FBS contains many uncharacterized components that may affect cellular functions, methods for serum-free cultures of ADSCs have been widely investigated. In this study, to develop an efficient method for a serum-free culture of ADSC-T, we used an ADSC line established by introducing the simian virus 40 (SV40) T gene into primary ADSCs. We then investigated the effect of amino acids, vitamins, and other components on the growth of ADSC-T. When the ADSC-T cells were plated with DMEM/F12 serum-free medium, the cells did not proliferate, and the mixture of amino acids, vitamins, and B27 supplement did not increase the growth of the cells. However, when the ADSC-T cells were provided with serum-free DMEM/F12 after they had been cultured with serum-supplemented DMEM for 24 h, the cells proliferated, and the vitamins and B27 supplement increased the cell growth. Stem-Pro serum-free medium also appeared to be useful as a suspension culture for the ADSC-T cells. The ADSC-T cells secreted large amounts of proteins of around 70 kDa. Insulin-like growth factor (IGF) and fibroblast growth factor basic (FGF basic) were secreted by ADSC-T in larger amounts in the serum-free culture than in the serum-supplemented culture.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.38 no.6
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• pp.343-353
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• 2012

Objectives: This aim of this study was to effectively isolate mesenchymal stem cells (hSMSCs) from human submandibular skin tissues (termed hSMSCs) and evaluate their characteristics. These hSMSCs were then chemically induced to the neuronal lineage and analyzed for their neurogenic characteristics in vitro. Materials and Methods: Submandibular skin tissues were harvested from four adult patients and cultured in stem cell media. Isolated hSMSCs were evaluated for their multipotency and other stem cell characteristics. These cells were differentiated into neuronal cells with a chemical induction protocol. During the neuronal induction of hSMSCs, morphological changes and the expression of neuron-specific proteins (by fluorescence-activated cell sorting [FACS]) were evaluated. Results: The hSMSCs showed plate-adherence, fibroblast-like growth, expression of the stem-cell transcription factors Oct 4 and Nanog, and positive staining for mesenchymal stem cell (MSC) marker proteins (CD29, CD44, CD90, CD105, and vimentin) and a neural precursor marker (nestin). Moreover, the hSMSCs in this study were successfully differentiated into multiple mesenchymal lineages, including osteocytes, adipocytes, and chondrocytes. Neuron-like cell morphology and various neural markers were highly visible six hours after the neuronal induction of hSMSCs, but their neuron-like characteristics disappeared over time (24-48 hrs). Interestingly, when the chemical induction medium was changed to Dulbecco's Modified Eagle Medium (DMEM) supplemented with fetal bovine serum (FBS), the differentiated cells returned to their hSMSC morphology, and their cell number increased. These results indicate that chemically induced neuron-like cells should not be considered true nerve cells. Conclusion: Isolated hSMSCs have MSC characteristics and express a neural precursor marker, suggesting that human skin is a source of stem cells. However, the in vitro chemical neuronal induction of hSMSC does not produce long-lasting nerve cells and more studies are required before their use in nerve-tissue transplants.

• Applied Microscopy
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• v.43 no.1
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• pp.27-33
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• 2013

Inflammatory cells express the inflammatory cytokines and growth factors induced by lipopolysaccharide (LPS). Odontoblasts are located at the pulp-dentin interface and extend their cell processes far into the dentin where they are the first cells to encounter microorganisms or their products. Therefore, this study examined the expression of some growth factors related to the signal pathway, such as growth factor receptor binding protein 2 (Grb2)-Ras in odontoblast-like dental pulp cells, after a treatment with LPS. After 60 minutes, the mRNA and protein expression levels of Grb2 and Ras were higher in the LPS-treated cells than in the control cells. The level of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) mRNA expression was increased significantly to a level similar to that of Grb2 and Ras at 60 minutes. The platelet-derived growth factor-AA (PDGF-AA) mRNA level was expressed strongly in the odontoblast like dental pulp cells without an association with LPS stimulation. Scanning electron microscopy revealed many extensions of the cytoplasmic processes and the number of processes increased gradually at 30, 60 and 90 minutes after LPS stimulation. From these results VEGF and bFGF expression might be induced through the Grb2-Ras signal transduction pathway in LPS treated odontoblasts.

• Journal of Microbiology and Biotechnology
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• v.30 no.1
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• pp.31-37
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• 2020

We previously identified a new heparinase inhibitor fungal metabolite, named CRM646-A, which showed inhibition of heparinase and telomerase activities in an in vitro enzyme assay and antimetastatic activity in a cell-based assay. In this study, we elucidated the mechanism by which CRM646-A rapidly induced nucleus condensation, plasma membrane disruption and morphological changes by increasing intracellular Ca²⁺ levels. Furthermore, PD98059, a mitogen-activated protein kinase (MEK) inhibitor, inhibited CRM646-A-induced nucleus condensation through ERK1/2 activation in rat 3Y1 fibroblast cells. We identified CRM646-A as a Ca²⁺ ionophore-like agent with a distinctly different chemical structure from that of previously reported Ca²⁺ ionophores. These results indicate that CRM646-A has the potential to be used as a new and effective antimetastatic drug.

• Journal of Periodontal and Implant Science
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• v.33 no.2
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• pp.225-246
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• 2003

Recent study on the enamel matrix derivatives explained on the effects of new bone and new attachment formation in infrabony pocket of periodontal defects. The purpose of this study was to investigate on the biological effects of enamel matrix derivatives to attachment, proliferation and activation of periodontal ligament and osteoblast cells, After treatment of osteoblast and PDL cells with various Emdogain concentration level(0.03${\mu}g$/ml, 3${\mu}g$/ml, 300${\mu}g$/ml), activation of osteogenetic factor, calcified nodule formation and measuring alkaline phosphatase activity(ALP) were performed. 1. Both osteoblast and PDL cell showed increasing initial cell attachment with 300${\mu}g$/ml Emdogain concentration. 2. At the level of 300${\mu}g$/ml, accelerated proliferation of oseoblast and PDL cell was appeared. 3. As Emdogain's concentration increased, increased ALP activation of osteoblast was shown. In case of PDL cell, Emdogain increased ALP activation prominently at the level of 300${\mu}g$/ml. 4. No statistically significant activating change were founded at all of the concentrations of Emdogain on the activating of transcript factor Runx2 for differentiating osteoblast. 5. At the level of 300${\mu}g$/ml, calcified nodule formation was increased prominently to compare with other concentration. These results indicated that Emdogain should activate initial attachment, proliferation and activation, but not on Runx2 activation and can be used for useful tool of the treatment of periodontal tissue regeneration.

• Journal of Life Science
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• v.17 no.5 s.85
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• pp.687-693
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• 2007

Insulin-like growth factor-I(IGF-I) has significant insulin-like anabolic effects which include the stimulation of glucose and amino acid uptake, as well as protein and glycogen synthesis. IGFs exist in serum and other biological fluids as complexes bound to a family of structurally related insulin-like growth factor binding proteins(IGFBPs). Six human IGFBPs can modulate the effects of IGFs on target tissues by several mechanisms, including altering the serum's half-life and the transcapillary transport of IGFs, as well as changing the availability of IGFs to specific cell surface receptors. Human fibroblasts secrete IGFBPs that can modify IGF-I action. Previous to our study using either Northern blotting, and Western blotting have shown that fibroblasts express mRNA IGFBP-3, -4, and -5, and synthesize these proteins. In addition, fibroblast cell lysates revealed that the IGFBP-3 was most abundant. For these reasons, we undertook to gain further insight into the effects of high and low glucose incubation condition on metabolism and IGFBP-3 expression. In results of metabolites and IGFBP-3 expression in GM10 cells cultivated with various glucose concentration, the consumption of glucose and accumulation of triglyceride were increased in condition of high glucose, and total protein level was decreased. in the course of time. After 5 days incubation, levels of free amino acid in medium containing glucose of high concentration glucose were higher than in conditions of low glucose. Although the levels of IGFBP-3 protein and mRNA levels were increased in low glucose, and IGFBP-3 was not affected by any pretense. Taken together, we suggest that the study of growth factors, like IGFs, might be a possible model of diabetes militus in cell, although the results in cell models were not in accord with in vivo.

• Reproductive and Developmental Biology
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• v.32 no.2
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• pp.105-110
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• 2008

The endogenous retrovirus-like elements (HERVs) found on several human chromosomes are somehow involved in gene regulation, especially during the transcription level. HERV-H, located on chromosome Xp22, may regulate gastrin-releasing peptide receptor (GRPR) in connection with diverse diseases. By suppression subtractive hybridization screen on SV40-immortalized lung fibroblast (WI-38 VA-13), we discovered that expression of HERV-HX2, a clustered HERV-H sequence on chromosome X, was upregulated in immortalized lung cells, compared to that of normal cells. Expression of HERV-HX2 was then analyzed in various cell lines, including normal somatic cells, cancer cells, SV40-immortalized cells, and undifferentiated and differentiated human embryonic stem cells. Expression of HERV-HX2 was specifically upregulated in continuously-dividing cells, such as cancer cells and SV40-immortalized cells. Especially, HERV-HX2 in HeLa cells was highly upregulated during the S phase of the cell cycle. Similar results were obtained in hES cells, in which undifferentiated cells expressed more HERV-HX2 mRNA than differentiated hES cells, including neural precursor and endothelial progenitor cells. Taken together, our results suggest that HERV-HX2 is upregulated in cancer cells and undifferentiated hES cells, whereas downregulated as differentiation progress. Therefore, we assume that HERV-HX2 may playa role on proliferation of cancer cells as well as differentiation of hES cells in the transcriptional level.

• The Journal of Korean Academy of Prosthodontics
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• v.43 no.3
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• pp.363-378
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• 2005

Statement of problem. Hydroxyapatite(HA) coated titanium surfaces have not yet showed the reliable osseointegration in various conditions. Purpose. This study was aimed to investigate microstructures, chemical composition, and surface roughness of the surface coated by the hydrothermal method and to evaluate the effect of hydrothermal coating on the cell attachment, as well as cell proliferation. Material and Methods. Commercially pure(c.p.) titanium discs were used as substrates. The HA coating on c.p. titanium discs by hydrothermal method was performed in 0.12M HCl solution mixed with HA(group I) and 0.1M NaOH solution mixed with HA(group II). GroupⅠ was heated at 180 $^{\circ}C$ for 24, 48, and 72 hours. GroupⅡ was heated at 180 $^{\circ}C$ for 12, 24, and 36 hours. And the treated surfaces were evaluated by Scanning electron microscopy(SEM), Energy dispersive X-ray spectroscopy(EDS), X-ray photoelectron spectroscopy(XPS), X-ray diffraction method(XRD), Confocal laser scanning microscopy(CLSM). And SEM of fibroblast and 3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide(MTT) assay were used for cellular responses of the treated surfaces. Results. The color of surface changed in both groups after the hydrothermal process. SEM images showed that coating pattern was homogeneous in group II, while inhomogeneous in group I. H72 had rosette-like precipitates. The crystalline structure grew gradually in group II, according to extending treatment period. The long needle-like crystals were prominent in N36. Calcium(Ca) and phosphorus(P) were not detected in H24 and H48 in EDS. In all specimens of group II and H72, Ca was found. Ca and P were identified in all treated groups through the analysis of XPS, but they were amorphous. Surface roughness did not increase in both groups after hydrothermal treatment. The values of surface roughness were not significantly different between groups I and II. According to the SEM images of fibroblasts, cell attachments were oriented and spread well in both treated groups, while they were not in the control group. However, no substantial amount of difference was found between groups I and II. Conclusions. In this study during the hydrothermal process procedure, coating characteristics, including the HA precipitates, crystal growth, and crystalline phases, were more satisfactory in NaOH treated group than in HCl treated group. Still, the biological responses of the modified surface by this method were not fully understood for the two tested groups did not differ significantly. Therefore, more continuous research on the relationship between the surface features and cellular responses seems to be in need.

• The Journal of Korean Academy of Prosthodontics
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• v.43 no.3
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• pp.393-408
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• 2005

Statement of problem. In the process of bone formation, titanium (Ti) surface roughness is an important factor modulating osteoblastic function. Purpose. This study was carried out to determine the effect of different Ti surface on biologic responses of a human osteoblast-like cell line (MG63). Materials and methods. MG63 cells were cultured on S (smooth), SLA (sandblasted largegrit & acid etching), HA (hydroxyapatite) Ti. The morphology and attachment of the cells were examined by SEM. The cDNAs prepared from total RNAs of MG63 were hybridized to a human cDNA microarray (1,152 elements). Results. The appearances of the surfaces observed with SEM were different in the three types of dental substrates. The surface of SLA and HA were shown to be rougher than S. MG63 cells cultured on SLA and HA were cell-matrix interaction. In the expression of genes involved in osseointegration, upregulated genes were bone morphogenetic protein, Villin, Integrin, Insulin-like growth factors in different surfaces. Downregulated genes were fibroblast growth factor receptor 4, Bcl 2-related protein, collagen, CD4 in different surfaces. Conclusion. The attachment and expression of key osteogenic regulatory genes were enhanced by surface roughness of the dental materials.