• 대한전기학회논문지:전력기술부문A
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• 제54권2호
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• pp.88-96
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• 2005

At present, the Korean electricity industry is undergoing restructuring and the Cost Based-generation Pool(CBP) market is being operated preparing for Two Way Bidding Pool(TWBP) market open. As the circumstance of the traditional system is changed according to power system deregulation, the simulation tool which should reflect market code providing market operating mechanism is needed to analyze an electricity market. This paper presents the development of an unique market simulator, Market Modeling and Price Simulator(MMPS) that is designed to imitate the Korean electricity market considering uniform price. The MMPS is developed in VB.NET and is composed of two modules that consist of market modeling and price simulation interfacing access database program. To evidence the features and the performance of MMPS, a small two way bidding market with 12-bus system and one way bidding market for generator competition will be presented for the electricity market simulations using MMPS.

• Asian Pacific Journal of Cancer Prevention
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• 제17권7호
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• pp.3043-3051
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• 2016

Controlled remodeling of the extracellular matrix (ECM) is essential for cell growth, invasion and metastasis. Matrix metalloproteinases (MMPs) are a family of secreted, zinc-dependent endopeptidases capable of degradation of ECM components. The expression and activity of MMPs in a variety of human cancers have been intensively studied. They play important roles at different steps of malignant tumor formation and have central significance in embryogenesis, tissue remodeling, inflammation, angiogenesis and metastasis. However, increasing evidence demonstrates that MMPs are involved earlier in tumorigenesis. Recent studies also suggest that MMPs play complex roles in tumor progression. MMPs and membrane type (MT)-MMPs are potentially significant therapeutic targets in many cancers, so that designing of specific MMP inhibitors would be helpful for clinical trials. Here, we review the pleiotropic roles of the MMP system in hematological malignancies in-vitro and in-vivo models.

• 한국동물생명공학회지
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• 제34권3호
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• pp.247-252
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• 2019

We observed MMPs expression in all sperm groups, with pro-MMP showing lower expression than active MMPs. According to the results from each freezing extender, the sperm membrane integrity (HOST: Hypoosmotic Swelling Test) analysis in TCGGD (Tris 250 mM, Citric acid 88 mM, Glucose 47 mM, Glycerol 3%, Dimethylsulpoxide 3.5 M) is 59.8 ± 0.7, TCGSD (Tris 250 mM, Citric acid 88 mM, Glucose 47 mM, Sucrose 0.1 M, Dimethylsulpoxide 3.5 M) is 59.3 ± 0.5 were significantly higher (p < 0.05) among the experimental groups. And MMPs analysis result, we observed MMPs expression in all sperm groups, with pro-MMP showing lower expression than active MMPs. The expression of active MMP-2 was the highest in sperms frozen in TCGSD and TCGD (Tris 250 mM, Citric acid 88 mM, Glucose 47 mM, Dimethylsulpoxide 3.5 M), Meanwhile, sperms from the TCGGD and TCGED (Tris 250 mM, Citric acid 88 mM, Glucose 47 mM, Ethylene glycol 3%, Dimethylsulpoxide 3.5 M) group showed lower level of active MMP-2 expression. Together, these results indicate that adding glycerol or sucrose to the sperm freezing buffer would not only suppress MMPs expression but also minimize DNA fragmentation, providing a mean to improve the success rate in the in vitro manipulation of rabbit sperms. Therefore, these results suggest that TCGGD or TCGSD extender method for freezing-thawing of rabbit sperm increased the viability after thawing.

• BMB Reports
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• 제36권1호
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• pp.128-137
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• 2003

Matrix metalloproteinases (MMPs), zinc dependent proteolytic enzymes, cleave extracellular matrix (ECM: collagen, laminin, firbronectin, etc) as well as non-matrix substrates (growth factors, cell surface receptors, etc). The deregulation of MMPs is involved in many diseases, such as tumor metastasis, rheumatoid arthritis, and periodontal disease. Metastasis is the major cause of death among cancer patients. In this review, we will focus on the roles of MMPs in tumor metastasis. The process of metastasis involves a cascade of linked, sequential steps that involve multiple host-tumor interactions. Specifically, MMPs are involved in many steps of tumor metastasis. These include tumor invasion, migration, host immune escape, extravasation, angiogenesis, and tumor growth. Therefore, without MMPs, the tumor cell cannot perform successful metastasis. The activities of MMPs are tightly regulated at the gene transcription levels, zymogen activation by proteolysis, and inhibition of active forms by endogenous inhibitors, tissue inhibitor of metalloproteinase (TIMP), and RECK. The detailed regulations of MMPs are described in this review.

• Journal of Plant Biotechnology
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• 제31권4호
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• pp.313-317
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• 2004

MMPs는 $Zn^{2+}$-의존성 endopeptidase로서 세포외 기질을 분해하는 능력을 갖고 있다. 본 연구에서는 담배식물체에서 잎의 발생단계별로 분비되는 MMPs의 활성과 환경 스트레스에 의한 MMPs의 활성을 조사하였다. 그 결과 MMPs의 활성은 기부 부위의 완전히 성숙한 잎보다 엽신의 확장이 일어나고 있는 어린잎에서 높았다. 이는 식물체에서 잎 신장을 위한 세포내 공간 형성 및 조직재구성에 MMPs가 중요한 단백질분해효소로 작용함을 시사하였다. 또한 환경 스트레스에 대한 반응으로서 MMPs의 활성을 조사한 결과 염처리와 병원균 감염에 의해 각각 1.2배와 1.5배의 증가를 보였다. 이러한 결과는 식물체가 발생단계 외에도 불리한 환경에 대한 방어 수단으로 MMPs가 생성 분비함을 알 수 있었다.

• Molecules and Cells
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• 제20권2호
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• pp.263-270
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• 2005

Transactivation of EGF-receptor (EGFR) by G-protein coupled receptors (GPCRs) is emerging as an important pathway in cell proliferation, which plays a crucial role in the development of atherosclerotic lesion. Angiotensin II (Ang II) has been identified to have a major role in the formation of atherosclerotic lesions, although the underlying mechanisms remain largely unclear. We hypothesize that Ang II promotes the proliferation and migration of smooth muscle cells through the release of heparin-binding epidermal growth factor like growth factor (HB-EGF), transactivation of EGFR and activation of Akt and Erk 1/2, with matrix metalloproteases (MMPs) playing a dispensable role. Primary rat aortic smooth muscle cells were used in this study. Smooth muscle cells rendered quiescent by serum deprivation for 12 h were treated with Ang II (100 nM) in the presence of either GM6001 ($20{\mu}M$), a specific inhibitor of MMPs or AG1478 ($10{\mu}M$), an inhibitor of EGFR. The levels of phosphorylation of EGFR, Akt and Erk 1/2 were assessed in the cell lysates. Inhibition of MMPs by GM6001 significantly attenuated Ang II-stimulated phosphorylation of EGFR, suggesting that MMPs may be involved in the transactivation of EGFR by Ang II receptor. Furthermore Ang II-stimulated proliferation and migration of smooth muscle cells were significantly blunted by inhibiting MMPs and EGFR and applying HB-EGF neutralization antibody, indicating that MMPs, HB-EGF and EGFR activation is necessary for Ang-II stimulated migration and proliferation of smooth muscle cells. Our results suggest that inhibition of MMPs may represent one of the strategies to counter the mitogenic and motogenic effects of Ang II on smooth muscle cells and thereby prevent the formation and development of atherosclerotic lesions.

• Restorative Dentistry and Endodontics
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• 제45권3호
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• pp.31.1-31.20
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• 2020

Matrix metalloproteinases (MMPs) are enzymes that can degrade collagen in hybrid layer and reduce the longevity of adhesive restorations. As scientific understanding of the MMPs has advanced, useful strategies focusing on preventing these enzymes' actions by MMP inhibitors have quickly developed in many medical fields. However, in restorative dentistry, it is still not well established. This paper is an overview of the strategies to inhibit MMPs that can achieve a long-lasting material-tooth adhesion. Literature search was performed comprehensively using the electronic databases: PubMed, ScienceDirect and Scopus including articles from May 2007 to December 2019 and the main search terms were "matrix metalloproteinases", "collagen", and "dentin" and "hybrid layer". MMPs typical structure consists of several distinct domains. MMP inhibitors can be divided into 2 main groups: synthetic (synthetic-peptides, non-peptide molecules and compounds, tetracyclines, metallic ions, and others) and natural bioactive inhibitors mainly flavonoids. Selective inhibitors of MMPs promise to be the future for specific targeting of preventing dentin proteolysis. The knowledge about MMPs functionality should be considered to synthesize drugs capable to efficiently and selectively block MMPs chemical routes targeting their inactivation in order to overcome the current limitations of the therapeutic use of MMPs inhibitors, i.e., easy clinical application and long-lasting effect.

• Clinical and Experimental Reproductive Medicine
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• 제25권2호
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• pp.161-170
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• 1998

Protein expression patterns of matrix metalloproteinases (MMPs) were examined in mouse reproductive organs during estrous cycle. Estrous cycle was classified into diestrus, proestrus, estrus or metestus and MMP expression was analyzed by zymography using gelatin as a substrate. Uterine fluid (UF) obtained both at diestrus and proestrus exhibited 4 major MMPs including 106kDa, 64kDa, 62kDa and 59kDa gelatinases. However, in UF at estrus, the gelatinolytic activity of 64kDa MMP disappeared and that of 106kDa and 62kDa MMPs dramatically decreased. At metestrus, 64kDa MMP activity reappeared and 106kDa and 62kDa MMP exhibited increased activities such that the band intensity of 106kDa was comparable to that in UF at diestrus. Gelatinolytic activity of 59kDa MMP was not changed throughout the cycle. Both ovarian and oviductal tissue homogenate revealed 4 MMPs which corresponded to the 4 MMPs of UF. However, unlike UF MMPs, gelatinolytic activity of these MMPs did not show distinct changes throughout the cycle. Either an inhibitor of MMP, 1,10-phenanthroline, or a metal chelator, EDTA, abolished the appearance of the above MMP activities in gelatinated gel whereas a serine proteinase inhibitor, phcnylmethylsulfonyl fluoride, failed to inhibit the appearance of MMP activities, proving that gelatinolytic activity of the above reproductive tissues were due to the enzymatic activity of MMP. When gclatinolytic activity of mouse serum was examined, it revealed 5 MMPs (131kDa, 106kDa, 89kDa, 64kDa and 62kDa bands) and one gelatinase (84kDa) band. From these results, it is concluded that the protein expression of MMPs of mouse reproductive organs, particularly uterus, is temporally regulated during estrous cycle and uterine 106kDa, 64kDa and 62kDa MMPs are suggested to play an important role in cyclic tissue remodeling of mouse uterus.

• Asian-Australasian Journal of Animal Sciences
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• 제26권3호
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• pp.334-342
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• 2013

Proteases and protease inhibitors play key roles in most physiological processes, including cell migration, cell signaling, and cell surface and tissue remodeling. Among these, the matrix metalloproteinase (MMPs) pathway is one of the most efficient biosynthetic pathways for controlling the activation of enzymes responsible for protein degradation. This also indicates the association of MMPs with the maturation of spermatozoa. In an attempt to investigate the effect of MMP activation and inhibitors in cultures with various hormones during sperm capacitation, we examined and monitored the localization and expression of MMPs (MMP-2 and MMP-9), tissue inhibitors of metalloproteinases (TIMP-2 and TIMP-3), as well as their expression profiles. Matured spermatozoa were collected from cultures with follicle-stimulating hormone (FSH), luteinizing hormone (LH), and Lutalyse at 1 h, 6 h, 18 h, and 24 h. ELISA detected the expression of MMP-2, MMP-9, TIMP-2, and TIMP-3 in all culture media, regardless of medium type (FSH-supplemented fertilization Brackett-Oliphant medium (FFBO), LH-supplemented FBO (LFBO), or Lutalyse-supplemented FBO (LuFBO)). TIMP-2 and TIMP-3 expression patterns decreased in LFBO and LuFBO. MMP-2 and MMP-9 activity in FBO and FFBO progressively increased from 1 h to 24 h but was not detected in LFBO and LuFBO. The localization and expression of TIMP-2 and TIMP-3 in sperm heads was also measured by immunofluorescence analysis. However, MMPs were not detected in the sperm heads. MMP and TIMP expression patterns differed according to the effect of various hormones. These findings suggest that MMPs have a role in sperm viability during capacitation. In conjunction with hormones, MMPs play a role in maintaining capacitation and fertilization by controlling extracellular matrix inhibitors of sperm.

• 대한의생명과학회지
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• 제18권2호
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• pp.104-111
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• 2012

Matrix metalloproteinases (MMPs) are zinc-dependent endopeptidases which degrade extracellular matrix (ECM) during embryogenesis, wound healing, and tissue remodeling. Dysregulation of MMP activity is also associated with various pathological inflammatory conditions. In this study, we examined the expression pattern of MMPs during PMA-induced differentiation of THP-1 monocytic cells into macrophages. We found that MMP1, MMP8, MMP3, MMP10, MMP12, MMP19, MMP9, and MMP7 were upregulated during differentiation whereas MMP2 remained unchanged. Expression of MMPs increased in a time-dependent manner; MMP1, MMP8, MMP3, MMP10, and MMP12 increased beginning at 60 hr post PMA treatment whereas MMP19, MMP9, and MMP7 increased beginning at 24 hr post PMA treatment. To identify signal transduction pathways involved in PMA-induced upregulation of MMPs, we treated PMA-differentiated THP-1 cells with specific inhibitors for PKC, MEK1, NF-${\kappa}B$, PI3K, p38 MAPK and PLC. We found that inhibition of the MEK1 pathway blocked PMA-induced upregulation of all MMPs to varying degrees except for MMP-2. In addition, expression of select MMPs was inhibited by PI3K, p38 MAPK and PLC inhibitors. In conclusion, we show that of the MMPs examined, most MMPs were up-regulated during differentiation of monocyte into macrophage via the MEK1 pathway. These results provide basic information for studying MMPs expression during macrophage differentiation.