Publications by authors named "Myung-Hee Moon"

Sphingosine 1-phosphate (S1P) is a bioactive lipid mediator that regulates multiple signals through S1P receptors responsible for biological responses. In particular, the S1P2 receptor has distinct roles in the S1P‑mediated differentiation of certain cell types. The present study was the first, to the best of our knowledge, to report the role of the S1P2 receptor in the adipocyte differentiation of 3T3‑L1 pre‑adipocytes.

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Sphingosine 1‑phosphate (S1P) belongs to a significant group of signaling sphingolipids and exerts most of its activity as a ligand of G‑protein‑coupled receptors. In our previous study, S1P demonstrated a novel biological activity with the anti‑adipogenesis of 3T3‑L1 preadipocytes. In the present study, we identified a possible mechanism of S1P‑mediated anti‑adipogenic effects, particularly in target pathways of the S1P receptors, including S1P1 and S1P2.

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Sphingosine-1-phosphate (S1P) is a pluripotent lipid mediator that transmits signals through G-protein-coupled receptors to control diverse biological processes. The novel biological activity of S1P in the adipogenesis of 3T3-L1 preadipocytes was identified in the present study. S1P significantly decreased lipid accumulation in maturing preadipocytes in a dose‑dependent manner.

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Prion diseases affect the central nervous system (CNS) in humans and animals, and are associated with the conversion of the cellular prion protein (PrPC) to the misfolded isoform (PrPSc). FTY720, an immune modulator and synthetic analogue of sphingosine-1-phosphate (S1P), activates S1P receptors and has been shown to be effective in experimental models of transplantation and autoimmunity, including multiple sclerosis. Whereas the immune modulatory functions of FTY720 have been extensively investigated, the other functions of FTY720 are not yet well understood.

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Prion diseases are a family member of neurodegenerative disorders caused by the accumulation of misfolded-prion proteins (scrapie form of PrP, PrP(Sc)). The accumulation of PrP(Sc) in the brain leads to neurotoxicity by the induction of mitochondrial-apoptotic pathways. Recent studies implicated gingerol in protection against neurodegeneration.

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Sphingosine-1-phosphate (S1P) is a pluripotent lipid mediator that transmits signals through a family of G-protein-coupled receptors (GPCRs) to control diverse biological processes including inflammation and wound-healing. In this study, a novel biological activity of S1P in articular chondrocytes was identified. Human primary chondrocytes were cultured in a monolayer.

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Sulforaphane, an aliphatic isothiocyanate derived from cruciferous vegetables, is known for its antidiabetic properties. The effects of sulforaphane on lipid metabolism in adipocytes are not clearly understood. Here, we investigated whether sulforaphane stimulates lipolysis.

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Insulin-like growth factor-1 (IGF-1) is one of the most important components of bovine colostrum. It exhibits antiapoptotic and antioxidative activities. Prion diseases are neurodegenerative disorders caused by cell death through mitochondrial dysfunction and increasing generation of reactive oxygen species (ROS).

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Higher levels of body fat are associated with an increased risk for development numerous adverse health conditions. FTY720 is an immune modulator and a synthetic analogue of sphingosine 1-phosphate (S1P), activated S1P receptors and is effective in experimental models of transplantation and autoimmunity. Whereas immune modulation by FTY720 has been extensively studied, other actions of FTY720 are not well understood.

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Sirtuin 1 (Sirt1) is a class III histone deacetylase that mediates the protective effects of neurons in neurodegenerative disorders, including Alzheimer's and prion disease. However, the mechanism directly involved in neuroprotection is still poorly understood. Recent evidence has demonstrated that activating Sirt1 induces autophagy, and that activating autophagy protects neurons against neurodegenerative disorders by regulating mitochondrial homeostasis.

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Our previous study revealed that resveratrol blocks prion protein peptide PrP(106-126)-induced neurotoxicity. However, the mechanism of resveratrol-mediated neuroprotection in prion diseases is not clear. Resveratrol initiates neuroprotective effects via the activation of autophagy, which protects organelles, cells, and organisms against misfolded protein-disorders, including Alzheimer's disease and Parkinson's disease via regulation of mitochondrial homeostasis.

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18β-Glycyrrhetinic acid (18β-GA) obtained from the herb liquorice has various pharmacological properties including anti-inflammatory and anti-bacterial activities. However, potential biological anti-obesity activities are unclear. In this study, novel biological activities of 18β-GA in the adipogenesis of 3T3-L1 preadipocytes and in lipolysis of differentiated adipocytes were identified.

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  Melatonin has neuroprotective effects in the models of neurodegenerative disease including Alzheimer's and Parkinson's disease. Several studies have shown that melatonin prevents neurodegeneration by regulation of mitochondrial function. However, the protective action of melatonin has not been reported in prion disease.

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Prions are the causative agents of transmissible spongiform encephalopathies, such as variant Creutzfeldt-Jakob disease in humans. Cellular prion proteins (PrPC) connect with cholesterol- and glycosphingolipid-rich lipid rafts through association of their glycosyl-phosphatidylinositol (GPI) anchor with saturated raft lipids and interaction of their N-terminal regions. Our previous study showed that cellular cholesterol enrichment prevented PrP(106-126)-induced neuronal death.

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The human prion protein fragment, PrP (106-126), may contain a majority of the pathological features associated with the infectious scrapie isoform of PrP, known as PrP(Sc). Based on our previous findings that hypoxia protects neuronal cells from PrP (106-126)-induced apoptosis and increases cellular prion protein (PrP(C)) expression, we hypothesized that hypoxia-related genes, including hypoxia-inducible factor-1 alpha (HIF-1α), may regulate PrP(C) expression and that these genes may be involved in prion-related neurodegenerative diseases. Hypoxic conditions are known to elicit cellular responses designed to improve cell survival through adaptive processes.

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Culture pH change has some important roles in signal transduction and secondary metabolism. We have already reported that acidic pH shock enhanced actinorhodin production in Streptomyces coelicolor. Among many potential governing factors on pH variation, the putative Na(+)/H(+) antiporter (sha) genes in S.

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Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a type II transmembrane cytokine and a potent inducer of apoptosis in cancer cells. However, some cancer cells, particularly prostate cancer cells, such as LNCaP cells, were found to be resistant to TRAIL. In the present study, we demonstrate that the proteasome inhibitor ALLN significantly enhanced TRAIL-induced apoptosis by up-regulating TRAIL/Apo2L death receptor 5 expression in LNCaP cells.

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Bee venom phospholipase A2 (bvPLA2) is a prototypic group III enzyme which consists of unique N-terminal and C-terminal domains and a central secretory PLA2 (sPLA2) domain. This sPLA2 domain is highly homologous with human group III sPLA2. Current evidence suggests that group III sPLA2 may affect some neuronal functions, such as neuritogenesis, neurotransmitter release and neuronal survival.

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Bisphosphonates (BPs) are widely used for the prevention and treatment of osteoporosis. However, there have been numerous reports of side effects of BPs, including osteonecrosis of the jaw. In the present study, we investigated whether hypoxia inhibits BP-induced apoptosis, and examined the mechanisms of this inhibition.

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Hypoxia occurs frequently in various solid tumors and elicits a cellular response designed to improve cell survival through adaptive processes, thereby accelerating cancer progression and the development of chemotherapy resistance. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), a member of the TNF superfamily, leads to tumor cell death via both intrinsic and extrinsic apoptotic signaling pathways. Hypoxia inhibits TRAIL-mediated apoptosis and attenuates the therapeutic activity of TRAIL in cancer management.

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Prion diseases are infectious neurodegenerative disorders characterized by the conversion of the cellular prion protein (PrPc) to the misfolded isoform (PrPsc). Prion peptide PrP 106-126 [PrP (106-126)] shares many physiological properties with PrPsc; it is neurotoxic in vitro and in vivo. PrP (106-126) induces neurotoxicity by the overexpression of PrPc and activation of the mitogen-activated protein (ERK1/2).

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Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), a member of the TNF superfamily of cytokines, is one of the most promising candidates for cancer therapeutics. However, many osteosarcomas are resistant to TRAIL. Bisphosphonates are very effective in the treatment of bone problems associated with malignancies; the antitumor effects are due to the inhibition of protein prenylation that is essential for cell function and survival.

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Prion diseases associated with the conversion of the cellular prion protein (PrP(C)) to the misfolded isoform (PrP(Sc)), affect the central nervous system (CNS) of humans and animals. Resveratrol, an activator of class III histone deacetylase SIRT1, is important in attenuating cellular injury and oxidative stress. The present study investigated the effects of SIRT1 activation on prion protein-mediated neuronal cell death and examined its possible signals in intracellular apoptotic pathways.

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The prion diseases are neurodegenerative disorders characterized by the conversion of the PrPc (normal cellular prion) to the PrPsc (misfolded isoform). The accumulation of PrPsc within the central nervous system (CNS) leads to neurocytotoxicity by increasing oxidative stress. In addition, many neurodegenerative disorders including prion, Parkinson's and Alzheimer's diseases may be regulated by cholesterol homeostasis.

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