• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.28 no.1
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• pp.42-45
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• 2002

Cultures of primary human alveolar bone-derived cells were established from alveolar bone chips obtained from normal individuals undergoing tooth extraction. These cells were expanded in vitro until passage 3 and used for the in vivo assays. Cells were loaded into transplantation vehicles, and transplanted subcutaneously into immunodeficient mice to study the capacities of human alveolar bone-derived cells to form bone in vivo. Transplants were harvested 12 weeks after transplantation and evaluated histologically. Of 10 human alveolar bone-derived cell transplants, two formed a bone-like tissue that featured osteocytes and mineral. Eight of the ten formed no osseous tissue. These results show that cells from normal human alveolar bone are capable of forming bone-like tissue when transplanted into immunodeficient mice.

• CELLMED
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• v.3 no.1
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• pp.3.1-3.3
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• 2013

The receptor activator of NF-${\kappa}B$ ligand (RANKL), a member of the tumor necrosis factor ligand family, has extensive functions beyond osteoclast development. RANKL is expressed in many immune cells such as osteoblasts, osteocytes, marrow stromal cells, activated T cells, synovial cells, keratinocytes, and mammary gland epithelial cells as well as in various tissues. The ligation of RANK by RANKL promotes dendritic cells (DCs) survival through prosurvival signals and the up-regulation of the anti-apoptotic proteins Bcl-2 and Bcl-$x_L$ and plays a crucial role in DCs-mediated Th1 differentiation. Therefore, RANKL plays an important role in the regulation of DCs/T cells-mediated specific immunity. This review will briefly inform our current understanding of the role of RANKL signaling in T cells-DCs communication in the immune system.

• Journal of Yeungnam Medical Science
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• v.26 no.1
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• pp.1-14
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• 2009

Human bone marrow-derived mesenchymal stem cells (MSCs) are a rare population of undifferentiated cells that have the capacity of self renewal and the ability to differentiate into mesodermal phenotypes, including osteocytes, chondrocytes, and adipocytes in vitro. Recently, MSCs have been shown to reside within the connective tissue of most organs, and their surface phenotype has been well analyzed. Many reports showed that transplanted MSCs enhanced regeneration as well as functional improvement of damaged organs and tissues. The wide differentiation plasticity of MSCs was expected to contribute to their demonstrated efficacy in a wide variety of experimental animal models and in human clinical trials. However, new findings suggest that the ability of MSCs to alter the tissue microenvironment via secretion of soluble factors may contribute more significantly than their capacity for differentiation in tissue repair. This review describes what is known about the cellular characteristics and differentiation potential of MSCs, which represent a promising stem cell population for further applications in regenerative medicine.

• Journal of Life Science
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• v.28 no.9
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• pp.1042-1047
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• 2018

The red algae Gracilaria vermiculophylla is widespread on seashores worldwide and has been used as food in Asian countries. Previous studies have reported that extracts of Gracilaria red algae have beneficial anti-oxidant and anti-inflammatory effects. The present study examined the anti-senescence effects of Gracilaria vermiculophylla extracts (GV-Ex) in replicatively senescent human bone marrow mesenchymal stem cells (hBM-MSCs). GV-Ex pretreatment improved the cellular viability of hBM-MSCs that had been injured by oxidative stress. These effects of GV-Ex were confirmed by MTT assay and immunoblot analysis using the apoptotic proteins p53 and cleaved caspase-3. The reactive oxygen species (ROS) levels were examined in long-term cultured Passages 17 (P-17) mesenchymal stem cells (MSC) and compared to P-7 MSC. The ROS accumulation was greater in the P-17 than in the P-7. However, these increased ROS levels in the P-17 were decreased significantly after treatment with GV-Ex, and restoration of the levels of the anti-oxidant enzymes SOD1, SOD2, and CAT was also observed under these conditions. In addition, P-17 hBM-MSC treated with GV-Ex had decreased levels of the senescence proteins p53, p21, and p16. The results show that the ability of P-17 hBM-MSC to differentiate into osteocytes and adipocytes was improved by GV-Ex treatment, suggesting that GV-Ex ameliorates the functional decline of senescent stem cells.

• Journal of Periodontal and Implant Science
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• v.32 no.1
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• pp.1-12
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• 2002

The periodontal ligament(PDL) is a unique tissue that is crucial for tooth function. However, little is known of the molecular mechanisms controlling PDL function. PDL-specific protein;PDLs22 had been previously identified as a novel protein isolated from cultured human PDL fibroblasts using subtraction hybridization between human gingival fibroblasts and PDL fibroblasts. The aim of this study was to examine the expression pattern and tissue localization of PDLs22 protein in embryonic and various postnatal stages of developing mouse using immunohistochemical staining. Embryos (E18) and postnatal (P1, P4, P5, P15, P18) were decapitated and the heads were fixed overnight in a freshly prepared solution of 4% paraformaldehyde. Some specimens were decalcified for $2{\sim}4$ weeks in a solution containing 10% of the disodium salt of ethylenediamine-tetraacetic acid (EDTA). Next, tissues were dehydrated, embedded in paraffin and sectioned serially at $6{\mu}m$ in thickness. Polyclonal antiserum raised against PDLs22 peptides, ISNKYLVKRQSRD, were made. The localization of PDLs22 in tissues was detected by polyclonal antibody against PDLs22 by means of immunohistochemical staining. The results were as follows; 1. Expression of PDLs22 protein was not detected in the tooth germ of bud and cap stage. 2. At the late bell stage and root formation stage, strong expression of PDLs22 protein was observed in developing tooth follicle, osteoblast-like cells, and subodontoblastic cells in the tooth pulp, but not in gingival fibroblasts, ameloblasts and odontoblasts of tooth germ 3. In erupted tooth, PDLs22 protein was intensely expressed in PDL and osteoblast-like cells of alveolar bone, but not in gingival fibroblasts, mature osteocytes and adjacent salivary glands. 4. In the developing alveolar bone and mid-palatal suture, expression of PDLs22 protein was seen in undifferentiated mesenchymal cells and osteoblast-like cells of developing mid-palatal suture, but not in mature osteocytes and chondrocytes. These results suggest that PDLs22 protein may play an important role in the differentiation of undifferentiated mesenchymal cells in the bone marrow and PDL cells, which can differentiate into multiple cell types including osteoblasts, cementoblasts, and PDL fibroblasts. However, more researches should be performed to gain a better understanding of the exact function of PDLs22 protein which related to the PDL cell differentiation.

• Korean Journal of Clinical Laboratory Science
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• v.55 no.4
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• pp.284-290
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• 2023

Adefovir dipivoxil (ADV) is used for the treatment of hepatitis and acquired immunodeficiency syndrome, but long-term use can cause osteoporosis. In this study, the effect of ADV on the osteocyte maturation process was evaluated at the level of undifferentiated cells using mesenchymal stem cells (MSCs) and osteoblasts (MG63). First, MSCs and MG63 cells were treated with ADV at different concentrations, and then a Cell Counting Kit-8 analysis was performed to determine the effect on the proliferation of each cell. Additionally, crystal violet and Hoechst staining were performed for the morphological analysis of each cell and nucleus. To determine the cause of cell hypertrophy, the transforming growth factor-beta (TGF-β) expression was investigated, and alkaline phosphatase (ALP) staining and activity were measured to determine the degree of differentiation of the MSCs and MG63 cells into mature osteocytes. The results confirmed that the ADV increases the expression of TGF-β in MSCs and MG63 cells, causing cellular and nuclear hypertrophy, and can cause osteoporosis by inhibiting cell proliferation and affecting the differentiation of mature osteocytes. Therefore, it is believed that these results can be used as a basis for understanding the adverse effects of ADV at a cytological level in basic medicine and clinical research.

• Archives of Reconstructive Microsurgery
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• v.24 no.2
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• pp.41-49
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• 2015

Free or pedicled vascularized fibular grafts (VFG) are useful for the reconstruction of large skeletal defects, particularly in cases of scarred or avascular beds, or in patients with combined bone and soft tissue defects. Compared to non-VFG, VEG, which contains living osteocytes and osteoblasts, maintains its own viability and serves as good osteoconductive and osteoinductive graft. Due to its many structural and biological advantages, the free fibular osteo- or osteocutaneous graft is considered the most suitable autograft for the reconstruction of long bone defects in the injured extremity. The traditional indication of VFG is the long bone and soft tissue defect, which cannot be reconstructed using a conventional operative method. Recently, the indications have been widely expanded not only for defects of midtibia, humerus, forearm, distal femur, and proximal tibia, but also for the arthrodesis of shoulder and knee joints. Because of its potential to allow further bone growth, free fibular epiphyseal transfer can be used for the hip or for distal radius defects caused by the radical resection of a tumor. The basic anatomy and surgical techniques for harvesting the VFG are well known; however, the condition of the recipient site is different in each case. Therefore, careful preoperative surgical planning should be customized in every patient. In this review, recently expanded surgical indications of VFG and surgical tips based on the author's experiences in the issues of fixation method, one or two staged reconstruction, size mismatching, overcoming the stress fracture, and arthrodesis of shoulder and knee joint using VFG are discussed with the review of literature.

• International Journal of Oral Biology
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• v.45 no.3
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• pp.92-98
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• 2020

Periodontitis is a bacteria-induced inflammatory disease associated with alveolar bone loss. Osteoclast is a macrophage-lineage cell that exhibits phagocytic activity; however, osteoclast phagocytic activity has not been demonstrated under pathological conditions. Diabetes is a pathological condition that exacerbates alveolar bone loss via periodontitis; therefore, we examined phagocytic osteoclasts in diabetic rats that had periodontitis. The rats were divided into the control (C), periodontitis (P), and diabetes with periodontitis (DP) groups. Diabetes and periodontitis were induced by streptozotocin injection and ligature of the mandibular first molars, respectively. On days 3 and 20 after the ligature, the rats were sacrificed, and osteoclasts containing inclusions were quantified by tartrate-resistant acid phosphatase staining. On day 3, there were more osteoclasts containing inclusions in the DP group than in the C group. Among inclusions, osteocyte-like cells and dense bodies were more frequently observed in the DP group than in the C group. Cytoplasm-like structures were elevated more in the DP group than in the C and P groups. However, no differences were observed on day 20. Interestingly, some osteoclasts were in contact with the osteocytes within the exposed lacunae and contained several inclusions within a large vacuole. Thus, the elevation of phagocytic osteoclasts in rats with diabetes and periodontitis provides insight into the role of osteoclast phagocytic activity under pathological conditions.

• Molecules and Cells
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• v.40 no.8
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• pp.598-605
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• 2017

Human mesenchymal stem cells (MSCs) are currently being evaluated as a cell-based therapy for tissue injury and degenerative diseases. Recently, several methods have been suggested to further enhance the therapeutic functions of MSCs, including genetic modifications with tissue- and/or diseasespecific genes. The objective of this study was to examine the efficiency and stability of transduction using an adenoviral vector in human MSCs. Additionally, we aimed to assess the effects of transduction on the proliferation and multipotency of MSCs. The results indicate that MSCs can be transduced by adenoviruses in vitro, but high viral titers are necessary to achieve high efficiency. In addition, transduction at a higher multiplicity of infection (MOI) was associated with attenuated proliferation and senescence-like morphology. Furthermore, transduced MSCs showed a diminished capacity for adipogenic differentiation while retaining their potential to differentiate into osteocytes and chondrocytes. This work could contribute significantly to clinical trials of MSCs modified with therapeutic genes.

• Biomolecules & Therapeutics
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• v.29 no.5
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• pp.527-535
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• 2021

Sclerostin (SOST), a regulator of bone formation in osteocytes, inhibits the canonical Wnt signaling by interacting with low-density lipoprotein receptor-related protein 5/6 (LRP5/6) to prevent Wnt binding. Loss-of-function mutations of the SOST gene caused massive bone outgrowth and SOST-null mouse exhibited a high bone density phenotype. Therefore, SOST has been suggested as a promising therapeutic target for osteoporosis. A few previous studies with X-ray crystallography identified the binding interfaces between LRP6 and SOST, but there are limitations in these studies as they used truncated SOST protein or SOST peptide. Here, we analyzed the conformational dynamics of SOST-LRP6 E1E2 complex using hydrogen/deuterium exchange mass spectrometry (HDX-MS). We examined the effect of the C-terminal tail of SOST on LRP6 conformation upon complex formation. HDX-MS analysis suggested a new potential binding interface for the C-terminal region of SOST that was missing from the previous crystal structure of the SOST-LRP6 E1E2 complex.