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Search Results: 1 - 10 of 27586 matches for " Min-Kyoung Park "
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Fucoidan from Marine Brown Algae Inhibits Lipid Accumulation
Min-Kyoung Park,Uhee Jung,Changhyun Roh
Marine Drugs , 2011, DOI: 10.3390/md9081359
Abstract: In this study, we elucidated the inhibitory effect of fucoidan from marine brown algae on the lipid accumulation in differentiated 3T3-L1 adipocytes and its mechanism. The treatment of fucoidan in a dose-dependent manner was examined on lipid inhibition in 3T3-L1 cells by using Oil Red O staining. Fucoidan showed high lipid inhibition activity at 200 μg/mL concentration ( P < 0.001). Lipolytic activity in adipocytes is highly dependent on hormone sensitive lipase (HSL), which is one of the most important targets of lipolytic regulation. Here, we examined the biological response of fucoidan on the protein level of lipolysis pathway. The expressed protein levels of total hormone sensitive lipase (HSL) and its activated form, phosphorylated-HSL were significantly increased at concentration of 200 μg/mL fucoidan. Furthermore, insulin-induced 2-deoxy-D-[ 3H] glucose uptake was decreased up to 51% in fucoidan-treated cells as compared to control. Since increase of HSL and p-HSL expression and decrease of glucose uptake into adipocytes are known to lead to stimulation of lipolysis, our results suggest that fucoidan reduces lipid accumulation by stimulating lipolysis. Therefore, these results suggest that fucoidan can be useful for the prevention or treatment of obesity due to its stimulatory lipolysis.
Buddleja officinalis Maximowicz Extract Inhibits Lipid Accumulation on Adipocyte Differentiation in 3T3-L1 Cells and High-Fat Mice
Changhyun Roh,Min-Kyoung Park,Hee-June Shin,Uhee Jung,Jin-Kyu Kim
Molecules , 2012, DOI: 10.3390/molecules17078687
Abstract: Obesity is a global health problem. It is also known to be a risk factor for the development of metabolic disorders, type 2 diabetes, systemic hypertension, cardiovascular disease, dyslipidemia, and atherosclerosis. In this study, we elucidated that Buddleja officinalis Maximowicz extract significantly inhibited lipid accumulation during 3T3-L1 adipocyte differentiation. Furthermore, Buddleja officinalis Maximowicz extract reduced the body weight gain induced through feeding a high-fat diet to C57BL/6 mice. The treatment of Buddleja officinalis Maximowicz extract significantly reduced the adipose tissue weight to 2.7/100 g of body weight in high-fat mice. When their adipose tissue morphology was investigated for histochemical staining, the distribution of cell size in the high-fat diet groups was hypertrophied compared with those from Buddleja officinalis Maximowicz extract-treated mice. In addition, in Buddleja officinalis Maximowicz extract-treated mice, a significant reduction of serum triglyceride and T-cholesterol was observed at to 21% and 17%, respectively. The discovery of bioactive compounds from diet or dietary supplementation is one of possible ways to control obesity and to prevent or reduce the risks of various obesity-related diseases. These results support that Buddleja officinalis Maximowicz extract is expected to create the therapeutic interest with respect to the treatment of obesity.
Effect of Acute and Fractionated Irradiation on Hippocampal Neurogenesis
Min-Kyoung Park,Seolhwa Kim,Uhee Jung,Insub Kim,Jin Kyu Kim,Changhyun Roh
Molecules , 2012, DOI: 10.3390/molecules17089462
Abstract: Ionizing radiation has become an inevitable health concern emanating from natural sources like space travel and from artificial sources like medical therapies. In general, exposure to ionizing radiation such as γ-rays is one of the methods currently used to stress specific model systems. In this study, we elucidated the long-term effect of acute and fractionated irradiation on DCX-positive cells in hippocampal neurogenesis. Groups of two-month-old C57BL/6 female mice were exposed to whole-body irradiation at acute dose (5 Gy) or fractional doses (1 Gy × 5 times and 0.5 Gy × 10 times). Six months after exposure to γ-irradiation, the hippocampus was analyzed. Doublecortin (DCX) immunohistochemistry was used to measure changes of neurogenesis in the subgranular zone (SGZ) of the hippocampal dentate gyrus (DG). The number of DCX-positive cells was significantly decreased in all acute and fractionally irradiation groups. The long-term changes in DCX-positive cells triggered by radiation exposure showed a very different pattern to the short-term changes which tended to return to the control level in previous studies. Furthermore, the number of DCX-positive cells was relatively lower in the acute irradiation group than the fractional irradiation groups (approximately 3.6-fold), suggesting the biological change on hippocampal neurogenesis was more susceptible to being damaged by acute than fractional irradiation. These results suggest that the exposure to γ-irradiation as a long-term effect can trigger biological responses resulting in the inhibition of hippocampal neurogenesis.
Anti-Obesity Effect of Nepetae spica Extract in High-Fat Mice
Changhyun Roh,Min-Kyoung Park,Hee-June Shin,Insub Kim,Jin Kyu Kim,Uhee Jung
Agriculture , 2012, DOI: 10.3390/agriculture2030204
Abstract: In recent years, obesity is the most common metabolic disease emerging as a global problem especially in developed nations. The discovery of bioactive compounds from natural plant extracts is one possible way to control obesity and prevent or reduce the risks of getting various obesity-related diseases. In this study, we elucidated that Nepetae spica extract significantly reduced the body weight gain induced through feeding a high-fat diet to C57BL/6 mice. The treatment of Nepetae spica extract significantly reduced the adipose tissue weight to 1.5/100 g of body weight in high-fat mice. When their adipose tissue morphology was investigated for histochemical staining, the distribution of cell size in the high-fat diet groups was hypertrophied compared with those from Nepetae spica extract-treated mice. In addition, in Nepetae spica extract-treated mice, a significant reduction of serum triglyceride and T-cholesterol was observed at to 13% and 16%, respectively. These results suggest that Nepetae spica extract could be useful for prevention or treatment of obesity.
Exosomes Derived from Mesenchymal Stem Cells Suppress Angiogenesis by Down-Regulating VEGF Expression in Breast Cancer Cells
Jong-Kuen Lee, Sae-Ra Park, Bong-Kwang Jung, Yoon-Kyung Jeon, Yeong-Shin Lee, Min-Kyoung Kim, Yong-Goo Kim, Ji-Young Jang, Chul-Woo Kim
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0084256
Abstract: Exosomes are small membrane vesicles released by a variety of cell types. Exosomes contain genetic materials, such as mRNAs and microRNAs (miRNAs), implying that they may play a pivotal role in cell-to-cell communication. Mesenchymal stem cells (MSCs), which potentially differentiate into multiple cell types, can migrate to the tumor sites and have been reported to exert complex effects on tumor progression. To elucidate the role of MSCs within the tumor microenvironment, previous studies have suggested various mechanisms such as immune modulation and secreted factors of MSCs. However, the paracrine effects of MSC-derived exosomes on the tumor microenvironment remain to be explored. The hypothesis of this study was that MSC-derived exosomes might reprogram tumor behavior by transferring their molecular contents. To test this hypothesis, exosomes from MSCs were isolated and characterized. MSC-derived exosomes exhibited different protein and RNA profiles compared with their donor cells and these vesicles could be internalized by breast cancer cells. The results demonstrated that MSC-derived exosomes significantly down-regulated the expression of vascular endothelial growth factor (VEGF) in tumor cells, which lead to inhibition of angiogenesis in vitro and in vivo. Additionally, miR-16, a miRNA known to target VEGF, was enriched in MSC-derived exosomes and it was partially responsible for the anti-angiogenic effect of MSC-derived exosomes. The collective results suggest that MSC-derived exosomes may serve as a significant mediator of cell-to-cell communication within the tumor microenvironment and suppress angiogenesis by transferring anti-angiogenic molecules.
The Role of p300 Histone Acetyltransferase in UV-Induced Histone Modifications and MMP-1 Gene Transcription
Min-Kyoung Kim, Jung-Min Shin, Hee Chul Eun, Jin Ho Chung
PLOS ONE , 2009, DOI: 10.1371/journal.pone.0004864
Abstract: Matrix metalloproteinase (MMP)-1 promotes ultraviolet (UV)-triggered long-term detrimental effects such as cancer formation and premature skin aging. Although histone modifications may play a crucial role in the transcriptional regulation of MMP-1, the relationship between UV-induced histone modification and MMP-1 expression is not completely understood. Here, we identify regulators of histone acetylation that may link UV-mediated DNA damage and MMP-1 induction by UV in cultured human dermal fibroblasts (HDFs) in vitro. UV irradiation of HDFs induced MMP-1 expression and increased the level of phosphorylation of H2AX (γ-H2AX), p53 and the acetylation of histone H3 (acetyl-H3). Total histone deacetylase (HDAC) enzymatic activity was decreased by UV irradiation, while histone acetyltransferase (HAT) activity was increased. Suppression of p300 histone acetyltransferase (p300HAT) activity by the p300HAT inhibitor anacardic acid (AA) or by down-regulation of p300 by siRNA prevented UV-induced MMP-1 expression and inhibited UV-enhanced γ-H2AX, p53 level, and acetyl-H3. Using chromatin immunoprecipitation assays, we observed that γ-H2AX, p53, acetyl-H3, p300 and c-Jun were consistently recruited by UV to a distinct region (?2067/?1768) adjacent to the p300 binding site (?1858/?1845) in the MMP-1 promoter. In addition, these recruitments of γ-H2AX, p53, acetyl-H3, p300 and c-Jun to the p300-2 site were significantly abrogated by post-treatment with AA. Furthermore, overexpression of p300 increased the basal and UV-induced MMP-1 promoter activity. Our results suggest that p300HAT plays a critical role in the transcriptional regulation of MMP-1 by UV.
Gliclazide Does Not Fully Prevent 2-Deoxy-D-Ribose-Induced Oxidative Damage Because It Does Not Restore Glutathione Content in a Pancreatic β-Cell Line
Gwanpyo Koh,Min-Kyoung Kim,Eun-Jin Yang,Dae-Ho Lee
Oxidative Medicine and Cellular Longevity , 2012, DOI: 10.1155/2012/390678
Abstract: We compared the effects of gliclazide, an antidiabetic agent with antioxidant properties, and N-acetyl-L-cysteine (NAC), a glutathione precursor, in protecting against 2-deoxy-D-ribose- (dRib-) induced oxidative damage in HIT-T15 cells. Using trypan blue staining and flow cytometry with annexin V/PI staining, gliclazide treatment slightly reversed dRib-induced cell death and apoptosis, and NAC treatment markedly reduced both measures. Likewise, flow cytometry using DHR 123 staining showed that the levels of dRib-induced reactive oxygen species (ROS) were partially suppressed by gliclazide and completely inhibited by NAC. Using electron spin resonance spectrometry, gliclazide and NAC scavenged hydroxyl radicals generated by Fenton reaction to a similar degree in a cell-free system. NAC, but not gliclazide, completely restored the intracellular glutathione depleted by dRib using monochlorobimane fluorescence and glutathione assays. Thus, gliclazide treatment suppressed dRib-induced oxidative damage in HIT-T15 cells less than NAC did because gliclazide did not restore the intracellular glutathione content as effectively as NAC. In addition, the elevation of intracellular glutathione rather than free radical scavenging might be an important mechanism for protecting against dRib-induced oxidative damage in a β-cell line.
Polarization Dependence Suppression of Optical Fiber Grating Sensor in a π-Shifted Sagnac Loop Interferometer
Jaebum Son,Min-Kyoung Lee,Myung Yung Jeong,Chang-Seok Kim
Sensors , 2010, DOI: 10.3390/s100504373
Abstract: In the sensing applications of optical fiber grating, it is necessary to reduce the transmission-type polarization dependence to isolate the sensing parameter. It is experimentally shown that the polarization-dependent spectrum of acousto-optic long-period fiber grating sensors can be suppressed in the transmission port of a π-shifted Sagnac loop interferometer. General expressions for the transmittance and reflectance are derived for transmission-type, reflection-type, and partially reflecting/transmitting-type polarization-dependent optical devices. The compensation of polarization dependence through the counter propagation in the Sagnac loop interferometer is quantitatively measured for a commercial in-line polarizer and an acousto-optic long-period fiber grating sensor.
The C-terminal region of Bfl-1 sensitizes non-small cell lung cancer to gemcitabine-induced apoptosis by suppressing NF-κB activity and down-regulating Bfl-1
Min-Kyoung Kim, Yoon-Kyung Jeon, Jong-Kyu Woo, Yun Choi, Dae-Han Choi, Yeul-Hong Kim, Chul-Woo Kim
Molecular Cancer , 2011, DOI: 10.1186/1476-4598-10-98
Abstract: Lung cancer remains a leading cause of cancer-related death [1] despite the introduction of several types of cytotoxic agents. In non-small cell lung cancer (NSCLC), chemotherapy often achieves limited clinical improvements due to acquired drug resistance and intolerable toxicities. Gemcitabine (difluorodeoxycytidine hydrochloride, dFdC) is a deoxycytidine analogue that is converted in vivo into the active metabolites, difluorodeoxycytidine di- and triphosphate (dFdCDP, dFdCTP). DFdCDP acts by inhibiting ribonucleotide reductase, whereas dFdCTP is incorporated into DNA and prevents DNA synthesis, thereby inducing apoptosis. Gemcitabine has been approved by the Food and Drug Administration (FDA) as a treatment for advanced and metastatic pancreatic cancer, ovarian cancer, breast cancer, and NSCLC, alone or in combination with other drugs http://www.cancer.gov/cancertopics/druginfo/gemcitabinehydrochloride webcite. Clinical trials have demonstrated that gemcitabine prolongs survival and improves the quality of life of advanced NSCLC patients [2]. In fact, gemcitabine is considered to be one of the most effective agents for treating NSCLC. Previous studies have concluded that when used as a single agent, gemcitabine consistently yields response rates exceeding 20%. Furthermore, preclinical data indicate that when used with platinum compounds, such as, cisplatin or carboplatin, gemcitabine has synergistic anti-tumor effects [3,4].However, gemcitabine often fails to achieve adequate disease control due to intrinsic or acquired resistance of tumor cells. The following are representative examples of putative resistance mechanisms; NF-κB and PI3K/Akt pathway activation in pancreatic and breast cancer [5,6] the up-regulation of anti-apoptotic Bcl-2 protein in pancreatic cancer [7,8] the deficiency of human equilibrate nucleoside transporter 1 in NSCLC [9]and alterations of gemcitabine metabolizing enzymes [10-13]. Many of these chemo-resistant mechanisms involve interrupting
Frontal White Matter Alterations in Short-Term Medicated Panic Disorder Patients without Comorbid Conditions: A Diffusion Tensor Imaging Study
Borah Kim, Jeong Hoon Kim, Min-Kyoung Kim, Kang Soo Lee, Youngki Kim, Tai Kiu Choi, Yun Tai Kim, Sang-Hyuk Lee
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0095279
Abstract: The frontal cortex might play an important role in the fear network, and white matter (WM) integrity could be related to the pathophysiology of panic disorder (PD). A few studies have investigated alterations of WM integrity in PD. The aim of this study was to determine frontal WM integrity differences between patients with PD without comorbid conditions and healthy control (HC) subjects by using diffusion tensor imaging. Thirty-six patients with PD who had used medication within 1 week and 27 age- and sex-matched HC subjects participated in this study. Structural brain magnetic resonance imaging was performed on all participants. Panic Disorder Severity Scale and Beck Anxiety Inventory (BAI) scores were assessed. Tract-based spatial statistics (TBSS) was used for image analysis. TBSS analysis showed decreased fractional anisotropy (FA) in frontal WM and WM around the frontal lobe, including the corpus callosum of both hemispheres, in patients with PD compared to HC subjects. Moreover, voxel-wise correlation analysis revealed that the BAI scores for patients with PD were positively correlated with their FA values for regions showing group differences in the FA of frontal WM of both hemispheres. Altered integrity in frontal WM of patients with PD without comorbid conditions might represent the structural pathophysiology in these patients, and these changes could be related to clinical symptoms of PD.
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