Han Bok Kwak

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RANKL, a member of tumor necrosis factor (TNF) superfamily, regulates the differentiation, activation, and survival of osteoclasts through binding to its cognate receptor, RANK. RANK can interact with several TNF-receptor-associated factors (TRAFs) and activates signaling molecules including Akt, NF-kappaB, and MAPKs. Although the transient elevation of(More)
Bone is a dynamic tissue that is regulated by the activity of bone-resorbing osteoclasts and bone-forming osteoblasts. Excessive osteoclast formation causes diseases such as osteoporosis and rheumatoid arthritis. Natural substances may be useful as therapeutic drugs to prevent many diseases in humans because they avoid the many side effects of treatment(More)
OBJECTIVE Interferon-gamma-inducible protein 10 (IP-10; also called CXCL10), a chemokine important in the migration and proliferation of T cells, is induced in a wide variety of cell types. However, the role of IP-10 in rheumatoid arthritis (RA) remains largely unknown. The purpose of this study was to examine the potential role of IP-10 in bone resorption(More)
Osteoclasts are responsible for bone erosion in diseases as diverse as osteoporosis, periodontitis, and rheumatoid arthritis. Natural plant-derived products have received recent attention as potential therapeutic and preventative drugs in human disease. The effect of rotenone in RANKL-induced osteoclast differentiation was examined in this study. Rotenone(More)
Osteoclasts, multinuclear cells specialized for bone resorption, differentiate from the monocyte/macrophage lineage of hematopoietic cells. Intervention in osteoclast differentiation is considered an effective therapeutic approach to the treatment of bone diseases involving osteoclasts. In this study, we found that tanshinone IIA, originating from Salvia(More)
Bone remodeling is accompanied by the differentiation of osteoclasts from the monocyte/macrophage lineage of hematopoietic cells. The osteoclast differentiation process requires receptor activator of nuclear factor kappa B (NF-kappa B) ligand (RANKL), which causes complex changes in the expression of various genes. In a cDNA microarray study to identify(More)
Tanshinone IIA isolated from Danshen is widely used in Oriental medicine. However, the action of tanshinone IIA in inflammatory bone-resorptive diseases remains unknown. Here we examined the effect of tanshinone IIA in inflammation-mediated osteoclastic bone resorption. Tanshinone IIA inhibited osteoclast differentiation in cocultures of bone marrow cells(More)
Osteoclasts are multinucleated cells with the unique ability to resorb bone. Elevated activity of these cells under pathologic conditions leads to the progression of bone erosion that occurs in osteoporosis, periodontal disease, and rheumatoid arthritis. Thus, the regulation of osteoclast apoptosis is important for bone homeostasis. In this study, we(More)
Osteoclasts are multinucleated cells that are formed by the fusion of mononuclear osteoclasts, which is an essential process in bone resorption leading to bone remodeling. Herein we show that GM-CSF promoted the fusion of prefusion osteoclasts (pOCs). The expression of GM-CSF receptor-alpha was significantly up-regulated at the fusion stage of pOCs induced(More)
In the field of osteoporosis, there has been growing interest in anabolic agents that enhance bone mass and improve bone architecture. In this study, we demonstrated that the ubiquitous plant triterpenoid, ursolic acid, enhances differentiation and mineralization of osteoblasts in vitro. We found that ursolic acid induced the expression of(More)