• Title/Summary/Keyword: Tissue inhibitor of matrix metalloproteinase-1

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Baicalein Inhibits the Migration and Invasion of B16F10 Mouse Melanoma Cells through Inactivation of the PI3K/Akt Signaling Pathway

  • Choi, Eun-Ok;Cho, Eun-Ju;Jeong, Jin-Woo;Park, Cheol;Hong, Su-Hyun;Hwang, Hye-Jin;Moon, Sung-Kwon;Son, Chang Gue;Kim, Wun-Jae;Choi, Yung Hyun
    • Biomolecules & Therapeutics
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    • v.25 no.2
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    • pp.213-221
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    • 2017
  • Baicalein, a natural flavonoid obtained from the rhizome of Scutellaria baicalensis Georgi, has been reported to have anticancer activities in several human cancer cell lines. However, its antimetastatic effects and associated mechanisms in melanoma cells have not been extensively studied. The current study examined the effects of baicalein on cell motility and anti-invasive activity using mouse melanoma B16F10 cells. Within the noncytotoxic concentration range, baicalein significantly inhibited the cell motility and invasiveness of B16F10 cells in a concentration-dependent manner. Baicalein also reduced the activity and expression of matrix metalloproteinase (MMP)-2 and -9; however, the levels of tissue inhibitor of metalloproteinase-1 and -2 were concomitantly increased. The inhibitory effects of baicalein on cell motility and invasiveness were found to be associated with its tightening of tight junction (TJ), which was demonstrated by an increase in transepithelial electrical resistance and downregulation of the claudin family of proteins. Additionally, treatment with baicalein markedly reduced the expression levels of lipopolysaccharide-induced phosphorylated Akt and the invasive activity in B16F10 cells. Taken together, these results suggest that baicalein inhibits B16F10 melanoma cell migration and invasion by reducing the expression of MMPs and tightening TJ through the suppression of claudin expression, possibly in association with a suppression of the phosphoinositide 3-kinase/Akt signaling pathway.

Effects of Kyejiinsam-tang in MIA-Induced Osteoarthritis Rats (계지인삼탕(桂枝人蔘湯)이 MIA로 유도된 골관절염 유발 Rat에 미치는 영향)

  • An, Soon-Sun;Heo, Dong-Seok
    • The Journal of Korean Medicine
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    • v.34 no.3
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    • pp.69-85
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    • 2013
  • Objectives: This study investigated the anti-osteoarthritic effects of Kyejiinsam-tang (hereinafter referred to KIT) on the monosodium iodoacetate (MIA)-induced osteoarthritis rats. Methods: Anti-oxidative effects of KIT were measured by scavenging activities of DPPH, reactive oxygen species (ROS) and nitric oxide (NO). Scavenging activities of anti-oxidation in lipopolysaccharide (LPS)-treated RAW 264.7 cells were also measured for inhibitory effects against the production of inflammatory mediators (tumor necrosis factor-${\alpha}$, interleukin-$1{\beta}$, interleukin-6). Osteoarthritis was induced in rats by injecting MIA in the knee joint. Rats were divided into a total of 4 groups (n=6). The normal group were not treated at all without inducing osteoarthritis whereas the control group were induced for osteoarthritis by MIA and oral medicated physiological saline per day. The positive comparison group was injected with MIA and after 7 days, 2 mg/kg of Indomethacin. The experimental group was injected with MIA and after 7 days was medicated with 34 mg/kg of KIT. Indomethacin and KIT were orally-medicated for each substance a total of 4 weeks, once per day. Weight-bearing on hind legs was measured every week after MIA injection. At the end of the experiment (5 weeks after MIA injection), micro CT (computed tomography)-arthrography and histopathological examinations on the articular structures of knee joint were performed. The effect on inflammatory cytokines and immunological cells in synovial fluid was measured. Volume of cartilage was measured by micro CT-arthrography. Injury to synovial tissue was measured by H & E (hematoxylin and eosin), Safranin-O immunofluorescence. Results: 1. Cytotoxicity against hFCs was insignificant. 2. KIT showed the potent full term for DPPH. 1. NO was significantly reduced by KIT (at 100, $200{\mu}g/m{\ell}$) and ROS was also reduced, but not significantly, by KIT (at $200{\mu}g/m{\ell}$). 2. IL-6 and IL-$1{\beta}$ were significantly reduced by KIT (at 100, $200{\mu}g/m{\ell}$) and TNF-${\alpha}$ was also reduced, but not significantly, by KIT (at $200{\mu}g/m{\ell}$). 1. In hind legs weight-bearing measurement, level of weight increased. 2. Functions of liver and kidney were not affected. 3. IL-$1{\beta}$ was significantly reduced and TNF-${\alpha}$, IL-6 were also reduced but not significantly. 4. PGE2 (prostaglandin E2), LTB4 (leukotriene B4) were significantly reduced in the KIT group. 5. MMP-9 (matrix metalloproteinase-9), TIMP-1 (tissue inhibitor of metalloproteinases-1) and Osteocalcin were significantly reduced in the KIT group. 6. Destruction of cartilage on micro CT arthrography was reduced but had no significant differences. 7. Histopathologically, injury to synovial membrane of the KIT group was decreased and proteoglycan content of KIT group was increased. Conclusions: According to this study, Kyejiinsam-tang has inhibiting effect on the progression of arthritis in MIA-induced osteoarthritis rat. Kyejiinsam-tang has anti-oxidants and anti-inflammation effects, and is related to inhibiting the activity of inflammatory cytokine and injury of volume in cartilage.

Immunohistochemical Studies for TIMP-1 and TIMP-2 Expression after Irradiation in Lung, Liver and Kidney of C57BL/6 Mouse (C57BL/96 Mouse의 폐, 간, 신장에서 방사선조사 후 TIMP-1, TIMP-2의 발현에 대한 면역조직화학적 연구)

  • Noh, Young-Ju;Ahn, Seung-Do;Kim, Jong-Hoon;Choi, Eun-Kyung;Chang, Hye-Sook
    • Radiation Oncology Journal
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    • v.19 no.2
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    • pp.181-189
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    • 2001
  • Purpose : Changes in the balance between MMP and TIMP can have a profound effect on the composition in the extracellular matrix (ECM) and affect various cellular functions including adhesion, migration, differentiation of cells, and fibrosis and invasion and metastasis of cancer cells. Radiation therapy is a popular treatment modality for benign and malignant tumor, but the study for radiation effect on MMP and TIMP is scarce. In the current study, we have examined the expression of TIMP in fibrosis-prone (C57BL/6) mice after radiation. Methods and Materials : Adult female mice of $10\~12$ weeks were used. The whole body were irradiated using a Varian CL-4/100 with 2 and 10 Gy. Immunohistochemical staining was peformed according to Avidin Biotin complex method and evaluated by observing high power field. For TIMP-1, TIMP-2 antibodies, reactivity was assessed in the parenchymal cell and in the stromal cell. The scale of staining was assessed by combining the quantitative and qualiative intensity of staining. Results : TIMP-1 immunoreactivity did not change in lung. But, in liver, TIMP-1 immunoreactivity was localized in cytoplasm of hepatocyte and Kupffer cell. in kidney, TIMP-1 immunoreactivity was localized in cytoplasm of some tubular cell. Temporal variations were not seen. Dose-response relationship was not seen except kidney. TIMP-2 immunoreactivity in lung was a score (++) at 0 Gy and elevated to a score (+++) at 2 Gy. TIMP-2 immunoreactivity was a score (++) in liver at 0 Gy. TIMP-2 immunoreactivity was localized in cytoplasm of hepatocyte and Kupffer cell as same as patterns of TIMP-1 immunoreactivity. The TIMP-2 immunoreactivity in liver was elevated to (+++) at 2 Gy. Immunoreactivity to TIMP-2 in kidney was a score (+++) at 0 Gy and was not changed at 10 Gy. The score of TIMP-2 immunoreactivity was reduced to (++) at 2 Gy. TIMP-2 immunoreactivity was confined to tubules in kidney. Temporal variation of TIMP-2 immunoreactivity was irregular. Dose-response relationship of TIMP-2 immunoreactivity was not seen. Conclusions : Differences between intensity of expression of TIMP-1 and TIMP-2 in each organ was present. Expression of TIMP was localized to specific cell in each organ. Irradiation increased TIMP-1 immunoreactivity in the liver and the kidney. Irradiation increased TIMP-2 immunoreactivity in the lung. But, in the liver and the kidney, TIMP-2 expression to radiation was irregular. Temporal variation of TIMP-2 immunoreactivity was irregular. Dose-response relationship of TIHP-2 immunoreactivity was not seen. In the future, we expect that the study of immunohistochemical staining of longer period of postirradiation and quantitative analysis using western blotting and northern blotting could define the role of TIMP in the radiation induced tissue fibrosis.

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Cordycepin Inhibits Migration and Invasion of HCT116 Human Colorectal Carcinoma Cells by Tightening of Tight Junctions and Inhibition of Matrix Metalloproteinase Activity (Cordycepin의 치밀결합 강화 및 MMPs의 활성 억제를 통한 HCT116 인체대장암세포의 이동성 및 침윤성의 억제)

  • Jeong, Jin Woo;Choi, Yung Hyun
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.43 no.1
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    • pp.86-92
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    • 2014
  • Cordycepin is the major functional component of Cordyceps species and is widely used in traditional oriental medicine. Cordycepin has been shown to possess many pharmacological properties, such as enhancement of immune function along with anti-inflammatory, antioxidant, anti-aging, and anti-cancer effects. Here, we investigated the inhibitory effects of cordycepin on cell migration and invasion, which are two critical cellular processes that are often deregulated during metastasis, using HCT116 human colorectal carcinoma cells. According to our data, cordycepin at non-cytotoxic concentrations markedly inhibited the motility and invasiveness of HCT116 cells in a time-dependent manner. RT-PCR and Western blotting results indicated that cordycepin reduced the levels of claudin proteins, which are major components of tight junctions (TJs), and induced tightening of TJs. Cordycepin also attenuated the expression and activities of matrix metalloproteinases (MMPs)-2 and -9, whereas levels of tissue inhibitor of metalloproteinases (TIMPs)-1 and -2 were simultaneously elevated. These findings suggest that cordycepin reduces the migration and invasion of HCT116 cells by modulating the activities of TJs and MMPs.

Inhibition of Migration and Invasion of Human Bladder Cancer 5637 cells by Hwangheuk-san (5637 인체 방광암세포의 이동성과 침윤성에 미치는 황흑산(黃黑散)의 영향)

  • Shim, Won-suk;Kim, Min-serh;Park, Sang-eun;Choi, Yung-hyun;Hong, Sang-hoon
    • The Journal of Internal Korean Medicine
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    • v.37 no.1
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    • pp.65-76
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    • 2016
  • Objectives: The purpose of this study was to identify the inhibitory effects of Hwangheuk-san (HHS), a Korean multi-herb formula comprising four medicinal herbs, on cell migration and invasion, two critical cellular processes that are often deregulated during metastasis, using the human bladder cancer 5637 cell line.Methods: Cell viability, motility, and invasion were assessed by 3-(4,5-dimethyl-2 thiazolyl)-2,5-diphnyl-2H-tetrazolium bromide (MTT), wound healing migration, and Transwell assays, respectively. Gene expression was detected by Western blot analysis. In addition, the activities of matrix metalloproteinases (MMPs) and the values for transepithelial electrical resistance (TER) were analyzed using a Gelatinase Activity Assay Kit and an Epithelial Tissue Voltohmmeter, respectively.Results: Our data indicated that within the concentration range that was not cytotoxic, HHS effectively inhibited the cell motility and invasiveness of 5637 cells. HHS markedly decreased the expression and activity of MMP-2 and MMP-9, which was associated with unregulation of tissue inhibitors of metalloproteinase (TIMP)-1 and TIMP-2. Further investigation revealed that phosphorylation of phosphatidylinositol 3-kinase (PI3K) and AKT was decreased in HHS-treated 5637 cells, and a PI3K/AKT inhibitor synergistically reduced the inhibition of migration and invasion and also inactivated MMP-2 and MMP-9. Moreover, HHS increased the tightening of tight junctions (TJs), which was demonstrated by an increase in the TER, and reduced the expression the levels of claudin family members (claudin-3 and -4), which are major components involved in the tightening of TJs.Conclusions: The present findings demonstrated that HHS attenuated the migration and invasion of bladder cancer 5637 cells by modulating the activity of the PI3K/Akt signaling pathway and also through TJ tightening.

Matrix metalloproteinases and Tissue inhibitors of matrix metalloproteinases in gingival crevicular fluids of periodontitis patients (치주염 환자의 치은열구액에서 MMPs와 TIMPs의 양의 변화)

  • Lee, Sun-Yun;Jung, Yeoun-Ho;Kim, Kyoung-Hwa;Yang, Byung-Keun;Han, Soo-Boo;Chung, Chong-Pyoung;Kim, Tae-Il;Ku, Young;Lee, Yong-Moo;Ko, Jae-Seung;Rhyu, In-Chul
    • Journal of Periodontal and Implant Science
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    • v.34 no.1
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    • pp.139-148
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    • 2004
  • MMPs(Matrix metalloproteinases)는 치주질환에서 주된 조직파괴단백분해효소인 것은 알려져 있고 TIMPs(Tissue inhibitor of Matrix metalloproteinase)는 MMPs의 작용을 억제한다라고 알려져 있다. 이 둘간의 불균형으로 인해서 조직파괴가 더 가속화될 수 있다. 이 두 연구의 목적은 ELISA kit를 사용하여 특정 MMPs(1,2,3,8,9,13)과 TIMPs(1,2)의 양이 건강한 환자와 비교하여서 치주염 환자에서 달라지는지 알아보고 MMPs(1,2,3,8,9,13), TIMPs(1,2)와 치은열구깊이와 GI score와의 관계를 알아보기로 한다. 8명의 만성 치주염 환자와 4명의 급속진행형 치주염 환자가 실험군으로 참여하였고 5명의 건강한 치주조직을 환자가 대조군으로 참여하였다. 임상적인 측정은 GI score와 치주낭측정을 통하여 이루어졌다. 8명의 만성 치주염을 가진 환자와 4명의 급속진행형 치주염을 가진 환자에서 각각 치주낭 깊이가 3mm이하인 부위에서 6개의 치은열구액 표본과 치주낭 깊이가 6mm 이상인 곳에서 6개의 치은열구액 표본을 채취하였다. 건강한 치주조직을 가진 5명의 환자는 단지 치주낭깊이가 3mm 이하인 건강한 부위에서만 치은열구액 표본을 제공하였다. MMPs(1,2,3,8,9,13)과 MIMPs(1,2)의 측정은 Human Biotrack ELISA kit를 사용하여서 측정하였다. 통계처리는 MMPs, MIMPs의 실험군과 대조군의 차이는 Kruskal-Wallis test를 사용하였고 MMPs, TIMPs와 치주낭 깊이와 GI score의 관계정도는 Pearson's correlation coefficient를 사용하였다. 실험결과 대조군과 비교하여 만성 치주염 환자에서 치주낭 깊이가 6mm 이상인 부위에서 MMP9의 수치가 통계적으로 유의할만하게 높았으며(p=0.04) MIMP2의 수치가 대조군과 비교하여 치주낭 깊이가 3mm 이하인 부위를 가진 만성치주염 환자에서 통계적으로 유의할만하게 높았다(=0.049). MMPs(1,2,3,8,9,13), MIMPs(1,2)의 활동성과 치주낭 깊이의 관계에서 둘간의 통계적으로 유의할만한 관계는 존재하지 않았으나 MMP1(r=0.35)과 MMP2(r=0.31)가 상대적으로 높은 관계를 보였다. 또한 MMPs(1,2,3,8,9,13), MIMPs(1,2)의 활동성과 GI score의 관계에서도 둘간의 통계학적으로 유의할만한 관계는 존재하지 않으나 MMP1(r=0.4), MMP2(r=0.29), MMP9(r=0.26)가 상대적으로 높은 관계를 보였다. 이 실험의 결과로 볼 때 MMP9가 만성치주염 환자의 질환이 있는 부위에서만 염증의 지표가 될 수 있으며 MIMP2가 만성치주염 환자의 염증이 없는 부위에서 높은 농도로 존재하는 것으로 보아서 MIMP2가 MMPs에 대한 억제작용을 하여서 염증의 진행을 방해하는 역할을 한다라고 볼 수 있다.

Improvement Effect of Corni Fructus 30% Ethanol Extract by MIA-Induced Osteoarthritis Animal Model (MIA로 골관절염 유발된 동물모델에서 산수유(山茱萸) 30% Ethanol 추출물의 개선 효과)

  • Kim, Min Ju;Lee, Jin A;Shin, Mi-Rae;Park, Hae-Jin;Roh, Seong-Soo
    • The Korea Journal of Herbology
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    • v.35 no.1
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    • pp.35-44
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    • 2020
  • Objectives : The objective of this study was to investigate the therapeutic effect of Corni Fructus 30% ethanol extract (CFE) on the monosodium iodoacetate (MIA)-induced osteoarthritis rats. Methods : The subjects were divided into 4 groups ; Normal group (N, n=10), MIA-induced osteoarthritis control group (Con, n=10), indomethacin 5 mg/kg treated group (INDO, n=10), CFE 200 mg/kg treated group (CFE, n=10). Blood and articulation tissues were collected after two weeks of drug administration. Oxidative stress was analyzed with reactive oxygen species (ROS), peroxynitrite (ONOO-). And the Nuclear factor erythroid-2 (Nrf2), heme oxygenase-1 (HO-1), superoxide dismutase (SOD), catalase, glutathione peroxidase-1/2 (GPx-1/2), Nuclear Factor Kappa B p65 (NF-κBp65), cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), tumor necrosis factor-alpha (TNFα), interleukin-6 (IL-6), Interleukin 1β (IL-1β), matrix metalloproteinase-1 (MMP-1), and tissue inhibitor of metalloproteinases-1 (TIMP-1) were investigated by western blot. Results : The administration of CFE showed a significant reduction of changes in relative hind paw weight distribution. Reactive oxygen species (ROS) and peroxy nitrite (ONOO-) levels of articulation tissues were significantly decreased in CFE compared to the control group. Western blot measurements of Nrf2, HO-1, SOD, catalase, GPx-1/2 showed that the CFE group was increased compared to the Con group. And western blot measurements of NF-κBp65, COX-2, iNOS, TNFα, IL-6, IL-1β showed that the CFE group was reduced compared to the Con group. Also CFE group decreased MMP-1 and increased TIMP-1. Conclusion : Based on the above results, it can be seen that osteoarthritis is improved when Corni Fructus 30% ethanol extract treated.

Expression of TIMP1, TIMP2 Genes by Ionizing Radiation (이온화 방사선에 의한 TIMP1, TIMP2 유전자 발현 측정)

  • Park Kun-Koo;Jin Jung Sun;Park Ki Yong;Lee Yun Hee;Kim Sang Yoon;Noh Young Ju;Ahn Seung Do;Kim Jong Hoon;Choi Eun Kyung;Chang Hyesook
    • Radiation Oncology Journal
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    • v.19 no.2
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    • pp.171-180
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    • 2001
  • Purpose : Expression of TIMP, intrinsic inhibitor of MMP, is regulated by signal transduction in response to genotoxins and is likely to be an important step in metastasis, angiogenesis and wound healing after ionizing radiation. Therefore, we studied radiation mediated TIMP expression and its mechanism in head and neck cancer cell lines. Materials and Methods : Human head and neck cancer cell lines established at Asan Medical Center were used and radiosensitivity $(D_0)$, radiation cytotoxicity and metastatic potential were measured by clonogenic assay, n assay and invasion assay, respectively. The conditioned medium was prepared at 24 hours and 48 hours after 2 Gy and 10 Gy irradiation and expression of TIMP protein was measured by Elisa assay with specific antibodies against human TIMP. hTIMP1 promoter region was cloned and TIMP1 luciferase reporter vector was constructed. The reporter vector was transfected to AMC-HN-1 and -HN-9 cells with or without expression vector Ras, then the cells were exposed to radiation or PMA, PKC activator. EMSA was peformed with oligonucleotide (-59/-53 element and SP1) of TIMP1 promoter. Results : $D_0$ of HN-1, -2, -3, -5 and -9 cell lines were 1.55 Gy, 1.8 Gy, 1.5 Gt, 1.55 Gy and 2.45 Gy respectively. n assay confirmed cell viability, over $94\%$ at 24hrs, 48hrs after 2 Gy irradiation and over 73% after 10 Gy irradiation. Elisa assay confirmed that cells secreted TIMP1, 2 proteins continuously. After 2 Gy irradiation, TIMP2 secretion was decreased at 24hrs in HN-1 and HN-9 cell lines but after 10 Gy irradiation, it was increased in all cell lines. At 48hrs after irradiation, it was increased in HN-1 but decreased in HN-9 cells. But the change in TIMP secretion by RT was mild. The transcription of TIMP1 gene in HN-1 was induced by PMA but in HN-9 cell lines, it was suppressed. Wild type Ras induced the TIMP-1 transcription by 20 fold and 4 fold in HN-1 and HN-9 respectively. The binding activity to -59/-53, AP1 motif was increased by RT, but not to SP1 motif in both cell lines. Conclusions : We observed the difference of expression and activity of TIMPs between radiosensitive and radioresistant cell line and the different signal transduction pathway between in these cell lines may contribute the different radiosensitivity. Further research to investigate the radiation response and its signal pathway of TIMPs is needed.

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Gene Expression of Metalloproteinases, Tissue Inhibitors of Metalloproteinases and Cytokines in Adriamycin-induced Cardiomyopathy (아드리아마이신으로 유도된 심근증에서 Metalloproteinase, Metalloproteinase 조직억제자, Cytokine 유전자 발현에 대한 연구)

  • Hong, Young Mi
    • Clinical and Experimental Pediatrics
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    • v.48 no.2
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    • pp.197-203
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    • 2005
  • Purpose : Changes in metalloproteinases(MMP) activity have been demonstrated in several disease states, including rheumatoid arthritis and tumor metastasis. More importantly, increased myocardial MMP activity has been reported to occur in both clinical and experimental forms of dilated cardiomyopathy. There was no report about MMP in adriamycin(ADR)-induced cardiomyopathy. The purpose of this study was to investigate gene expression of MMP and tissue inhibitor of metalloproteinases(TIMP) in ADR-induced cardiomyopathy and clarify the relationship between MMP and cytokines. Methods : Male Sprague-Dawley rats were divided into two groups. The first group was control. The second group was given intraperitoneal injections of ADR(5 mg/kg) twice a week over two weeks. Serum concentrations of MMP, TIMP, interleukin(IL)-6 and tumor necrosis factor(TNF)-${\alpha}$ were measured. RNA extraction was performed from frozen rat hearts. Reverse transcription polymerase chain reaction(RT-PCR) was employed. cDNA Microarray analysis was performed by using a set of 5,184 sequence-verified rat cDNA clones. Results : Serum MMP and TIMP levels were not significantly different between the two groups. IL-6 was $36.8{\pm}2.8pg/mL$ and TNF-${\alpha}$ $2.2{\pm}2.7pg/mL$ in the ADR group. They were significantly higher than in the control group. Serum MMP correlated significantly with TNF-${\alpha}$(r=0.41, P<0.05). There was no gene expression of MMP, IL-6 or TNF-${\alpha}$ in the hearts of both groups. Gene expression of TIMP was significantly depressed in the hearts of the ADR group. Conclusion : These results suggested a potential role for TNF-${\alpha}$ in the regulation of extracellular matrix remodeling in ADR induced cardiomyopathy. Rapid screening of multiple decreased gene expression by DNA chip may be a useful diagnostic test to detect early cardiac injury before developing ADR induced cardiomyopathy.

MMP-1 and TIMP-1 production in MG-63 cells stimulated with Prevotella nigrescens Lipopolysaccharide (Prevotella nigrescens lipopolysaccharides로 자극된 MG63 세포에서 분비되는 기질금속단백질 MMP-1과 TIMP-1의 수준에 관한 연구)

  • Yang Won-Kyung;Kim Mi-Ri;Shon Won-Jun;Lee In-Bog;Cho Byeong-Hoon;Um Chung-Moon;Son Ho-Hyun
    • Restorative Dentistry and Endodontics
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    • v.29 no.5
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    • pp.470-478
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    • 2004
  • The purpose of this study is to monitor the secretion of matrix metalloproteinase-1 (MMP-1) and tissue inhibitor of metalloproteinase-1 (TIMP-1) produced by human osteosarcoma cell line (MG63) stimulated with Prevotella nigrescens lipopolysaccharides (LPS). and to compare the level of secretion before and after the treatment of calcium hydroxide on P. nigrescens LPS. LPS was extracted and purified from anaerobically cultured P. nigrescens. MG63 cells were stimulated by the LPS (0, 1, $10{\;}\mu\textrm{g}/ml$) or LPS($10{\;}\mu\textrm{g}/ml$) pretreated with 12.5 mg/ml of $Ca(OH)_2$ for 3 days. Total RNA was isolated from the cell. and real-time quantitative polymerase chain reaction (PCR) was performed for quantification of MMP-1 and TIMP-1. The results were as follows. 1. MMP-1 mRNA expression at 48 hr was highly increased by stimulation with P. nigrescens LPS. The increase was dose-dependent. 2. When stimulated with ($1{\;}\mu\textrm{g}/ml$ of LPS. TIMP-1 mRNA expression was highly increased at 24 hr and 48 hr. However. TIMP-1 expression was suppressed at higher concentration ($10{\;}\mu\textrm{g}/ml$). 3. When P. nigrescens LPS was pretreated with $Ca(OH)_2$. MMP-1 and TIMP-1 gene expression was downregulated. The results of this study suggest that transcriptional regulation of MMP-1 and TIMP-1 by P. nigrescens LPS could be one of the important mechanisms in bone resorption of periapical inflammation. The result of calcium hydroxide on MMP-1 and TIMP-1 gene expression suppression shows that calcium hydroxide detoxified bacterial LPS and thus should be used the medication of choice for intracanal dressings in root canal infected with black-pigmented bacteria.