• Archives of Plastic Surgery
• /
• v.34 no.2
• /
• pp.141-148
• /
• 2007

Purpose: The object of this study was to evaluate the development of continuous osteogenic differentiation and bone formation after the subcutaneous implantation of the tissue-engineered bone, in vitro. Methods: Human adipose-derived stem cells were obtained by proteolytic digestion of liposuction aspirates. Adipose-derived stem cells were seeded in PLGA scaffolds after being labeled with PKH26 and cultured in osteogenic differentiation media for 1 month. The PLGA scaffolds with osteogenic stimulated adipose-derived stem cells were implanted in subcutaneous layer of four nude mice. Osteogenesis was assessed by RT-PCR for mRNA of osteopontin and bone sialoprotein(BSP), and immunohistochemistry for osteocalcin, and von Kossa staining for calcification of extracellular matrix at 1 and 2 months. Results: Implanted PLGA scaffold with adipose-derived stem cells were well vascularized, and PLGA scaffolds degraded and were substituted by host tissues. The mRNA of osteopontin and BSP was detected by RT-PCR in both osteogenic stimulation group and also osteocalcin was detected by immunohistochemistry at osteogenic stimulation 1 and 2 months, but no calcified extracellular deposit in von Kossa stain was found in all groups. Conclusion: In vivo, it could also maintain the characteristics of osteogenic differentiation that adipose-derived stem cells within PLGA scaffold after stimulation of osteogenic differentiation in vitro, but there were not normal bone formation in subcutaneous area. Another important factor to consider is in vivo, heterologous environment would have negative effect on bone formation as.[p1]

• Nutrition Research and Practice
• /
• v.15 no.4
• /
• pp.444-455
• /
• 2021

BACKGROUND/OBJECTIVES: Adipocytes undergo angiogenesis to receive nutrients and oxygen needed for adipocyte' growth and differentiation. No study relating quercetin with angiogenesis in adipocytes exists. Therefore, this study investigated the role of quercetin on adipogenesis in 3T3-L1 cells, acting through matrix metalloproteinases (MMPs). MATERIALS/METHODS: After proliferating preadipocytes into adipocytes, various quercetin concentrations were added to adipocytes, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays were performed to evaluate cell proliferation. Glycerol-3-phosphate dehydrogenase (GPDH) activity was investigated as an indicator of fat accumulation. The mRNA expressions of transcription factors related to adipocyte differentiation, CCAAT/enhancer-binding proteins (C/EBPs), peroxisomal proliferatoractivated receptors (PPAR)-γ, and adipocyte protein 2 (aP2), were investigated. The mRNA expressions of proteins related to angiogenesis, vascular endothelial growth factor (VEGF)-α, vascular endothelial growth factor receptor (VEGFR)-2, MMP-2, and MMP-9, were investigated. Enzyme activities and concentrations of MMP-2 and MMP-9 were also measured. RESULTS: Quercetin treatment suppressed fat accumulation and the expressions of adipocyte differentiation-related genes (C/EBPα, C/EBPβ, PPAR-γ, and aP2) in a concentration-dependent manner in 3T3-L1 cells. Quercetin treatments reduced the mRNA expressions of VEGF-α, VEGFR-2, MMP-2, and MMP-9 in 3T3-L1 cells. The activities and concentrations of MMP-2 and MMP-9 were also decreased significantly as the concentration of quercetin increased. CONCLUSIONS: The results confirm that quercetin inhibits adipose tissue differentiation and fat accumulation in 3T3-L1 cells, which could occur through inhibition of the angiogenesis process related to MMPs.

• The Journal of Korean Academy of Prosthodontics
• /
• v.44 no.1
• /
• pp.73-84
• /
• 2006

The importance of soft tissue response to implant abutments has become one of the major issues in current implant dentistry. To date, numerous studies have emphasized on maintaining connective tissue barriers in quantity, as well as in quality fir the long term success of dental implants. The cells mainly consisting the soft tissue around dental implants are fibroblasts and epithelial cells. The mechanism of the fibroblasts adhesions to certain substrata can be explained by the 'focal adhesion' theory. On the other hand, epithelial cells adhere tn the substratum via hemidesmosomes. The typical integrin-mediated adhesions of cells to certain matrix are called 'cell-matrix adhsions'. The focal adhesion complex of fibroblasts, in relation to the cell-matrix adhsions, consists of the extracellular matrix(ECM) such as fibronectin, the transmembrane proteins such as integrins, the intracellular cytoplasmic proteins such as vinculin, talin, and more, and the cytoskeletal structures such as filamentous actin and microtubules. The mechanosensory function of integrins and focal adhesion complexes are considered to play a major role in the cells adhesion, migration, proliferation, differentiation, division, and even apoptosis. The '3-D matrix adhesions' defined by Cukierman et al. makes a promising future for the verification of the actual process of the cell-matrix adhesions in vivo and can be applied to the field of implant dentistry in relation to obtaining strong soft tissue attachment to the implant abutments.

• International Journal of Oral Biology
• /
• v.47 no.4
• /
• pp.55-62
• /
• 2022

Bioactive flavonoids have been shown to improve the biological activity of stem cells derived from different sources in tissue regeneration. The goal of this study was to see how naringin, a natural flavonoid discovered in citrus fruits, affected the biological properties of human dental pulp stem cells (HDPSCs). In this study, we found that naringin increases the migratory ability of HDPSCs. Naringin increased matrix metalloproteinase-2 (MMP-2) and C-X-C chemokine receptor type 4 (CXCR4) mRNA and protein expression in HDPSCs. ARP100, a selective MMP-2 inhibitor, and AMD3100, a CXCR4 antagonist, both inhibited the naringin-induced migration of HDPSCs. Furthermore, naringin increased osteogenic differentiation of HDPSCs and the expression of the osteogenic-related marker, alkaline phosphatase in HDPSCs. Taken together, our findings suggest that naringin may be beneficial on dental tissue or bone regeneration by increasing the biological activities of HDPSCs.

• Journal of Animal Reproduction and Biotechnology
• /
• v.38 no.3
• /
• pp.121-130
• /
• 2023

Background: Coating a culture plate with molecules that aid in cell adhesion is a technique widely used to produce animal cell cultures. Extracellular matrix (ECM) is known for its efficiency in promoting adhesion, survival, and proliferation of adherent cells. Gelatin, a cost-effective type of ECM, is widely used in animal cell cultures including feeder-free embryonic stem (ES) cells. However, the optimal concentration of gelatin is a point of debate among researchers, with no studies having established the optimal gelatin concentration. Methods: In this study, we coated plastic plates with gelatin in a concentration-dependent manner and assessed Young's modulus using atomic force microscopy (AFM) to investigate the microstructure of the surface of each plastic plate. The adhesion, proliferation, and differentiation of the ESCs were compared and analyzed revealing differences in surface microstructure dependent on coating concentration. Results: According to AFM analysis, there was a clear difference in the microstructure of the surface according to the presence or absence of the gelatin coating, and it was confirmed that there was no difference at a concentration of 0.5% or more. ES cell also confirmed the difference in cell adhesion, proliferation, and differentiation according to the presence or absence of gelatin coating, and also it showed no difference over the concentration of 0.5%. Conclusions: The optimum gelatin-coating for the maintenance and differentiation of ES cells is 0.5%, and the gelatin concentration-mediated microenvironment and ES cell signaling are closely correlated.

• IMMUNE NETWORK
• /
• v.22 no.5
• /
• pp.43.1-43.12
• /
• 2022

Osteoclasts (OCs) are clinically important cells that resorb bone matrix. Accelerated bone destruction by OCs is closely linked to the development of metabolic bone diseases. In this study, we screened novel chemical inhibitors targeting OC differentiation to identify drug candidates for metabolic bone diseases. We identified that 1,3-dibenzyl-5-fluorouracil, also named OCI-101, is a novel inhibitor of osteoclastogenesis. The formation of multinucleated OCs is reduced by treatment with OCI-101 in a dose-dependent manner. OCI-101 inhibited the expression of OC markers via downregulation of receptor activator of NF-κB ligand and M-CSF signaling pathways. Finally, we showed that OCI-101 prevents ovariectomy-induced bone loss by suppressing OC differentiation in mice. Hence, these results demonstrated that OCI-101 is a good drug candidate for treating metabolic bone diseases.

• Toxicological Research
• /
• v.22 no.3
• /
• pp.283-291
• /
• 2006

The survival and growth of epithelial cells depends on adhesion to the extracellular matrix. An adhesion signal may regulate the initiation of differentiation, since epidermal keratinocytes differentiate as they leave the basement membrane. A metabolically dead cornified cell envelope is the end point of epidermal differentiation so that this process may be viewed as a specialized form of programmed cell death. In order to investigate the precise cellular signaling events loading to terminal differentiation of keratinocytes, we have utilized HaCaT cells to monitor the biological consequences of $Ca^{2+}$ stimulation and numerous downstream signaling pathways, including activation of the extracellular signal-regulated protein kinase(ERK) pathway and activation of phosphatidylinositol 3-kinase(PI3K). The results presented in this study show that $Ca^{2+}$ function as potent agents for the differentiation of HaCaT keratinocytes, and this differentiation depends or the activation of ERK, Protein kinase B(PKB) and p70 ribosomal protein S6 kinase(p70S6K). Finally, the results show that the expression of Activator protein 1(AP-1; c-Jun and c-Fos) increased following $Ca^{2+}$-mediated differentiation of HaCaT cells, suggesting that ERK-mediated AP-1 expression is critical for initiating the terminal differentiation of keratinocytes.

• BMB Reports
• /
• v.49 no.12
• /
• pp.655-661
• /
• 2016

Polymer brush is a soft material unit tethered covalently on the surface of scaffolds. It can induce functional and structural modification of a substrate's properties. Such surface coating approach has attracted special attentions in the fields of stem cell biology, tissue engineering, and regenerative medicine due to facile fabrication, usability of various polymers, extracellular matrix (ECM)-like structural features, and in vivo stability. Here, we summarized polymer brush-based grafting approaches comparing self-assembled monolayer (SAM)-based coating method, in addition to physico-chemical characterization techniques for surfaces such as wettability, stiffness/elasticity, roughness, and chemical composition that can affect cell adhesion, differentiation, and proliferation. We also reviewed recent advancements in cell biological applications of polymer brushes by focusing on stem cell differentiation and 3D supports/implants for tissue formation. Understanding cell behaviors on polymer brushes in the scale of nanometer length can contribute to systematic understandings of cellular responses at the interface of polymers and scaffolds and their simultaneous effects on cell behaviors for promising platform designs.

• Proceedings of the KIEE Conference
• /
• 1992.07b
• /
• pp.567-569
• /
• 1992

Design sensitivity analysis is proposed for the optimal shape design of three dimensional magnetostatic problems. The direct differentiation method is introduced for design sensitivity analysis and the boundary element method with reduced magnetic scalar potential as the state variable is used to analyze the magnetic characteristics. In the direct differentiation method, the design sensitivity, defined as the total derivative of the objective function with respect to the design variables, is calculated based on the variation of the state variable with respect to the design variable. And the variation of He state variable is calculated by differentiating the both sides of the system matrix equation obtained by applying boundary element method. Through the numerical example with simple electromagnet, the usefullness is proved.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.29 no.2 s.43
• /
• pp.105-130
• /
• 2003

Human skin equivalents, also designated as cultured skin substitute (Boyce and Warden, 2002) or organotypic co-cultures (Maas-Szabowski et al., 1999, 2000, 2003), are three-dimensional systems that are engineered by seeding fibroblasts into a three-dimensional dermal matrix. Such a dermal equivalent is then subsequently seeded with human keratinocytes. After cell attachment, the culture is kept first under submerged condition to allow keratinocyte proliferation. Thereafter, the culture is lifted the air-liquid interface (A/L) to expose the epidermal compartment to the air, and to further induce keratinocyte differentiation. During the air-exposure, nutrients from the medium will diffuse through the underlying dermal substrate towards the epidermal compartment and support keratinocyte proliferation and differentiation. Under these conditions, a HSE is formed that shows high similarity with the native tissue from which it was derived (Figure 1) (Bell et at., 1981; Boyce et al., 1988; Ponec et al., 1997;El Ghalbzouri et al.., 2002).